Minimization of power consumption during charging of superconducting accelerating cavities

NASA Astrophysics Data System (ADS)

Bhattacharyya, Anirban Krishna; Ziemann, Volker; Ruber, Roger; Goryashko, Vitaliy

2015-11-01

The radio frequency cavities, used to accelerate charged particle beams, need to be charged to their nominal voltage after which the beam can be injected into them. The standard procedure for such cavity filling is to use a step charging profile. However, during initial stages of such a filling process a substantial amount of the total energy is wasted in reflection for superconducting cavities because of their extremely narrow bandwidth. The paper presents a novel strategy to charge cavities, which reduces total energy reflection. We use variational calculus to obtain analytical expression for the optimal charging profile. Energies, reflected and required, and generator peak power are also compared between the charging schemes and practical aspects (saturation, efficiency and gain characteristics) of power sources (tetrodes, IOTs and solid state power amplifiers) are also considered and analysed. The paper presents a methodology to successfully identify the optimal charging scheme for different power sources to minimize total energy requirement.

Megawatt solar power systems for lunar surface operations

NASA Technical Reports Server (NTRS)

Adams, B.; Alhadeff, S.; Beard, S.; Carlile, D.; Cook, D.; Douglas, C.; Garcia, D.; Gillespie, D.; Golingo, R.; Gonzalez, D.

1990-01-01

The work presented here shows that a solar power system can provide power on the order of one megawatt to a lunar base with a fairly high specific power. The main drawback to using solar power is still the high mass, and therefore, cost of supplying energy storage through the solar night. The use of cryogenic reactant storage in a fuel cell system, however, greatly reduces the total system mass over conventional energy storage schemes.

Way-Scaling to Reduce Power of Cache with Delay Variation

NASA Astrophysics Data System (ADS)

Goudarzi, Maziar; Matsumura, Tadayuki; Ishihara, Tohru

The share of leakage in cache power consumption increases with technology scaling. Choosing a higher threshold voltage (Vth) and/or gate-oxide thickness (Tox) for cache transistors improves leakage, but impacts cell delay. We show that due to uncorrelated random within-die delay variation, only some (not all) of cells actually violate the cache delay after the above change. We propose to add a spare cache way to replace delay-violating cache-lines separately in each cache-set. By SPICE and gate-level simulations in a commercial 90nm process, we show that choosing higher Vth, Tox and adding one spare way to a 4-way 16KB cache reduces leakage power by 42%, which depending on the share of leakage in total cache power, gives up to 22.59% and 41.37% reduction of total energy respectively in L1 instruction- and L2 unified-cache with a negligible delay penalty, but without sacrificing cache capacity or timing-yield.

Antioxidant activity of honey supplemented with bee products.

PubMed

Juszczak, Lesław; Gałkowska, Dorota; Ostrowska, Małgorzata; Socha, Robert

2016-06-01

The aim of this work was to evaluate the influence of supplementation of multiflower honey with bee products on the phenolic compound content and on antioxidant activity. Average total phenolic and flavonoids contents in the multiflower honeys were 36.06 ± 10.18 mg GAE/100 g and 4.48 ± 1.69 mg QE/100 g, respectively. The addition of royal jelly did not affect significantly the phenolic compound content and antioxidant activity. Supplementation of honey with other bee products, i.e. beebread, propolis, pollen, resulted in significant increase in the total phenolic and flavonoids contents, and in antiradical activity and reducing power, with the largest effect found for addition of beebread. Significant linear correlations between the total phenolic and flavonoids contents and antiradical activity and reducing power were found.

Influence of conventional and ultrasonic-assisted extraction on phenolic contents, betacyanin contents, and antioxidant capacity of red dragon fruit (Hylocereus polyrhizus).

PubMed

Ramli, Nurul Shazini; Ismail, Patimah; Rahmat, Asmah

2014-01-01

The aim of this study was to examine the effects of extraction methods on antioxidant capacities of red dragon fruit peel and flesh. Antioxidant capacities were measured using ethylenebenzothiozoline-6-sulfonic acid (ABTS) radical cation assay and ferric reducing antioxidant power assay (FRAP). Total phenolic content (TPC) was determined using Folin-Ciocalteu reagent while quantitative determination of total flavonoid content (TFC) was conducted using aluminium trichloride colorimetric method. Betacyanin content (BC) was measured by spectrophotometer. Red dragon fruit was extracted using conventional (CV) and ultrasonic-assisted extraction (UE) technique to determine the most efficient way of extracting its antioxidant components. Results indicated that UE increased TFC, reduced the extraction yield, BC, and TPC, but exhibited the strongest scavenging activity for the peel of red dragon fruit. In contrast, UE reduced BC, TFC, and scavenging activity but increased the yield for the flesh. Nonetheless, UE slightly increases TPC in flesh. Scavenging activity and reducing power were highly correlated with phenolic and flavonoid compounds. Conversely, the scavenging activity and reducing power were weakly correlated with betacyanin content. This work gives scientific evidences for the consideration of the type of extraction techniques for the peel and flesh of red dragon fruit in applied research and food industry.

Influence of Conventional and Ultrasonic-Assisted Extraction on Phenolic Contents, Betacyanin Contents, and Antioxidant Capacity of Red Dragon Fruit (Hylocereus polyrhizus)

PubMed Central

Ramli, Nurul Shazini; Ismail, Patimah; Rahmat, Asmah

2014-01-01

The aim of this study was to examine the effects of extraction methods on antioxidant capacities of red dragon fruit peel and flesh. Antioxidant capacities were measured using ethylenebenzothiozoline-6-sulfonic acid (ABTS) radical cation assay and ferric reducing antioxidant power assay (FRAP). Total phenolic content (TPC) was determined using Folin-Ciocalteu reagent while quantitative determination of total flavonoid content (TFC) was conducted using aluminium trichloride colorimetric method. Betacyanin content (BC) was measured by spectrophotometer. Red dragon fruit was extracted using conventional (CV) and ultrasonic-assisted extraction (UE) technique to determine the most efficient way of extracting its antioxidant components. Results indicated that UE increased TFC, reduced the extraction yield, BC, and TPC, but exhibited the strongest scavenging activity for the peel of red dragon fruit. In contrast, UE reduced BC, TFC, and scavenging activity but increased the yield for the flesh. Nonetheless, UE slightly increases TPC in flesh. Scavenging activity and reducing power were highly correlated with phenolic and flavonoid compounds. Conversely, the scavenging activity and reducing power were weakly correlated with betacyanin content. This work gives scientific evidences for the consideration of the type of extraction techniques for the peel and flesh of red dragon fruit in applied research and food industry. PMID:25379555

Operating results of a KU30 diesel cogeneration plant

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

Shioda, Kiyoshi; Kakinuma, Takashi; Nishido, Takashi

1995-11-01

Diesel cogeneration plants provide high generation ratios, the ability to operate on heavy fuel oil, small space requirements, short delivery terms and easy starting and stopping. The Mitsubishi type KU30 diesel engine is well-suited for meeting the demands of these applications. The KU30 engine (bore 300 x stroke 380 mm) covers an output range from 3500 to 5000 kW at 720 or 750 r/min. Performance results show that total power failures have completely disappeared, thanks to improvements in stable power supply and the reliability of the power source. They also show that the rate of private power generation has accountedmore » for more than 90% of total power consumption in the plant, and that the unit cost of electric power could be reduced by three yen (per kilowatt hour) compared with that of purchased power. This paper describes the design and operating results from a typical plant.« less

White Nail Radio Transmitter: Billion Dollar Savings through Energy Efficiency

DTIC Science & Technology

2011-05-10

increase efficiency and reduce overall energy consumption ashore by 50 percent CNO, Navy Energy Vision, P 10 White Nail Vision Your Cell Phone Cell...Estimated Total Number of transmitters 3,000,000 Estimated total power saved Watt 1,250,000,000 Cell Phone Transmitter Efficiency 1.25 Gigawatts saved...Greenhouse Gas Power 4 1 Energy Navy Use 7.3 Billion kWh White Nail Cell Phone Savings 11 Billion kWh One and a half times!!! Saves the output of four of

Total phenolic contents and free-radical scavenging activities of grape (Vitis vinifera L.) and grape products.

PubMed

Keser, Serhat; Celik, Sait; Turkoglu, Semra

2013-03-01

Grape is one of the world's largest fruit crops, with an approximate annual production of 58 million metric tons, and it is well known that the grape skins, seeds and stems, waste products generated during wine and grape juice processing, are rich sources of polyphenols. It contains flavonoids, phenolic acids and stilbenes. In this study, we tried to determine antioxidant properties and phenolic contents of grape and grape products (fresh fruit, seed, dried fruit, molasses, pestil, vinegar) of ethanol and water extracts. Antioxidant properties of extracts were investigated by DPPH(√), ABTS(√+), superoxide, H(2)O(2) scavenging, reducing power, metal chelating activity and determination of total phenolic contents. The seed extracts revealed highest ABTS(√+), DPPH(√), H(2)O(2) scavenging and reducing power activities. Furthermore, these extracts showed higher total phenolic contents than other grape product extracts.

Antioxidant capacity and phenolic acids of virgin coconut oil.

PubMed

Marina, A M; Man, Y B Che; Nazimah, S A H; Amin, I

2009-01-01

The antioxidant properties of virgin coconut oil produced through chilling and fermentation were investigated and compared with refined, bleached and deodorized coconut oil. Virgin coconut oil showed better antioxidant capacity than refined, bleached and deodorized coconut oil. The virgin coconut oil produced through the fermentation method had the strongest scavenging effect on 1,1-diphenyl-2-picrylhydrazyl and the highest antioxidant activity based on the beta-carotene-linoleate bleaching method. However, virgin coconut oil obtained through the chilling method had the highest reducing power. The major phenolic acids detected were ferulic acid and p-coumaric acid. Very high correlations were found between the total phenolic content and scavenging activity (r=0.91), and between the total phenolic content and reducing power (r=0.96). There was also a high correlation between total phenolic acids and beta-carotene bleaching activity. The study indicated that the contribution of antioxidant capacity in virgin coconut oil could be due to phenolic compounds.

Antioxidant and Anti-Fatigue Constituents of Okra

PubMed Central

Xia, Fangbo; Zhong, Yu; Li, Mengqiu; Chang, Qi; Liao, Yonghong; Liu, Xinmin; Pan, Ruile

2015-01-01

Okra (Abelmoschus esculentus (L.) Moench), a healthy vegetable, is widely spread in tropical and subtropical areas. Previous studies have proven that okra pods possess anti-fatigue activity, and the aim of this research is to clarify the anti-fatigue constituents. To achieve this, we divided okra pods (OPD) into seeds (OSD) and skins (OSK), and compared the contents of total polysaccharides, total polyphenols, total flavonoids, isoquercitrin, and quercetin-3-O-gentiobiose and the antioxidant activity in vitro and anti-fatigue activity in vivo between OSD and OSK. The contents of total polyphenols and total polysaccharides were 29.5% and 14.8% in OSD and 1.25% and 43.1% in OSK, respectively. Total flavonoids, isoquercitrin and quercetin-3-O-gentiobiose (5.35%, 2.067% and 2.741%, respectively) were only detected in OSD. Antioxidant assays, including 1-diphenyl-2-picrylhydrazyl (DPPH) scavenging, ferric reducing antioxidant power (FRAP) and reducing power test, and weight-loaded swimming test showed OSD possessed significant antioxidant and anti-fatigue effects. Moreover, biochemical determination revealed that that anti-fatigue activity of OSD is caused by reducing the levels of blood lactic acid (BLA) and urea nitrogen (BUN), enhancing hepatic glycogen storage and promoting antioxidant ability by lowering malondialdehyde (MDA) level and increasing superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) levels. These results proved okra seeds were the anti-fatigue part of okra pods and polyphenols and flavonoids were active constituents. PMID:26516905

Reducing ultrafine particle emissions using air injection in wood-burning cookstoves

DOE PAGES

Rapp, Vi H.; Caubel, Julien J.; Wilson, Daniel L.; ...

2016-06-27

In order to address the health risks and climate impacts associated with pollution from cooking on biomass fires, researchers have focused on designing new cookstoves that improve cooking performance and reduce harmful emissions, specifically particulate matter (PM). One method for improving cooking performance and reducing emissions is using air injection to increase turbulence of unburned gases in the combustion zone. Although air injection reduces total PM mass emissions, the effect on PM size-distribution and number concentration has not been thoroughly investigated. Using two new wood-burning cookstove designs from Lawrence Berkeley National Laboratory, this research explores the effect of air injectionmore » on cooking performance, PM and gaseous emissions, and PM size distribution and number concentration. Both cookstoves were created using the Berkeley-Darfur Stove as the base platform to isolate the effects of air injection. The thermal performance, gaseous emissions, PM mass emissions, and particle concentrations (ranging from 5 nm to 10 μm in diameter) of the cookstoves were measured during multiple high-power cooking tests. Finally, the results indicate that air injection improves cookstove performance and reduces total PM mass but increases total ultrafine (less than 100 nm in diameter) PM concentration over the course of high-power cooking.« less

Reducing ultrafine particle emissions using air injection in wood-burning cookstoves

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

Rapp, Vi H.; Caubel, Julien J.; Wilson, Daniel L.

In order to address the health risks and climate impacts associated with pollution from cooking on biomass fires, researchers have focused on designing new cookstoves that improve cooking performance and reduce harmful emissions, specifically particulate matter (PM). One method for improving cooking performance and reducing emissions is using air injection to increase turbulence of unburned gases in the combustion zone. Although air injection reduces total PM mass emissions, the effect on PM size-distribution and number concentration has not been thoroughly investigated. Using two new wood-burning cookstove designs from Lawrence Berkeley National Laboratory, this research explores the effect of air injectionmore » on cooking performance, PM and gaseous emissions, and PM size distribution and number concentration. Both cookstoves were created using the Berkeley-Darfur Stove as the base platform to isolate the effects of air injection. The thermal performance, gaseous emissions, PM mass emissions, and particle concentrations (ranging from 5 nm to 10 μm in diameter) of the cookstoves were measured during multiple high-power cooking tests. Finally, the results indicate that air injection improves cookstove performance and reduces total PM mass but increases total ultrafine (less than 100 nm in diameter) PM concentration over the course of high-power cooking.« less

Pedalium murex Linn (Pedaliaceae) fruits: a comparative antioxidant activity of its different fractions

PubMed Central

Patel, DK; Kumar, R; Prasad, SK; Hemalatha, S

2011-01-01

Objective To examine the antioxidant activity and total phenolic content of different solvent fractions of Pedalium murex (P. murex) Linn fruits (Family: Pedaliaceae) as well as the correlation between the total antioxidant capacity and total phenolic content. Methods In the present study, the antioxidant activities of P. murex were evaluated using six in-vitro assays, namely total antioxidant assay, DPPH assay, reducing power, nitric oxide scavenging, hydrogen peroxide scavenging and deoxyribose scavenging assays, and total phenol contents were also investigated. Results The ethyl acetate (EA) fraction was found to have high levels of phenolic content (298.72±2.09 mg GAE/g). The EA fraction exhibit higher total antioxidant capacity, higher percentage of DPPH radical scavenging activity (135.11±2.95µg/mL), nitric oxide (200.57±4.51µg/mL), hydrogen peroxide (217.91±6.12 µg/mL), deoxyribose (250.01±4.68µg/mL) and higher reducing power. Correlation coefficient (r2=0.914) was found to be significant between total phenolic content and total antioxidant activity. Conclusions In general, the results indicate that the EA fractions are rich in phenolic antioxidants with potent free radical scavenging activity implying their importance to human health. PMID:23569800

Comparison of sound power radiation from isolated airfoils and cascades in a turbulent flow.

PubMed

Blandeau, Vincent P; Joseph, Phillip F; Jenkins, Gareth; Powles, Christopher J

2011-06-01

An analytical model of the sound power radiated from a flat plate airfoil of infinite span in a 2D turbulent flow is presented. The effects of stagger angle on the radiated sound power are included so that the sound power radiated upstream and downstream relative to the fan axis can be predicted. Closed-form asymptotic expressions, valid at low and high frequencies, are provided for the upstream, downstream, and total sound power. A study of the effects of chord length on the total sound power at all reduced frequencies is presented. Excellent agreement for frequencies above a critical frequency is shown between the fast analytical isolated airfoil model presented in this paper and an existing, computationally demanding, cascade model, in which the unsteady loading of the cascade is computed numerically. Reasonable agreement is also observed at low frequencies for low solidity cascade configurations. © 2011 Acoustical Society of America

Evaluation of the antioxidant activity of four edible mushrooms from the Central Anatolia, Eskisehir - Turkey: Lactarius deterrimus, Suillus collitinus, Boletus edulis, Xerocomus chrysenteron.

PubMed

Sarikurkcu, Cengiz; Tepe, Bektas; Yamac, Mustafa

2008-09-01

The methanolic extracts of Lactarius deterrimus, Suillus collitinus, Boletus edulis, Xerocomus chrysenteron were analyzed for their antioxidant activities in different test systems namely beta-carotene/linoleic acid, DPPH free radical scavenging, reducing power and metal chelating activities in addition to their total phenolic and flavonoid contents. In beta-carotene/linoleic acid and DPPH systems, L. deterrimus and B. edulis showed the strongest activity patterns. Their activities were as strong as the positive controls. The reducing power of the species was excellent. Chelating capacity of the extracts was increased with the increasing concentration. On the other hand, B. edulis found to have the highest phenolic content. Total flavonoid content of S. collitinus found the superior to the other mushrooms.

Experimental Investigation on Design Enhancement of Axial Fan Using Fixed Guide Vane

NASA Astrophysics Data System (ADS)

Munisamy, K. M.; Govindasamy, R.; Thangaraju, S. K.

2015-09-01

Airflow passes through the rotating blade in an axial flow fan will experience a helical flow pattern. This swirling effect leads the system to experience swirl energy losses or pressure drop yet reducing the total efficiency of the fan system. A robust tool to encounter this air spin past the blade is by introducing guide vane to the system. Owing to its importance, a new approach in designing outlet guide vane design for a commercial usage 1250mm diameter axial fan with a 30° pitch angle impeller has been introduced in this paper. A single line metal of proper curvature guide vane design technique has been adopted for this study. By choosing fan total efficiency as a target variable to be improved, the total and static pressure on the design point were set to be constraints. Therefore, the guide vane design was done based on the improvement target on the static pressure in system. The research shows that, with the improvement in static pressure by 29.63% through guide vane installation, the total fan efficiency is increased by 5.12%, thus reduces the fan power by 5.32%. Good agreement were found, that when the fan total efficiency increases, the power consumption of the fan is reduced. Therefore, this new approach of guide vane design can be applied to improve axial fan performance.

CHALLENGES AND OPPORTUNITIES FOR EMISSION REDUCTIONS FROM THE COAL-FIRED POWER SECTOR IN GROWING ECONOMIES: THE CASE OF COAL-FIRED ELECTRIC UTILITY PLANTS IN RUSSIA

EPA Science Inventory

China, Russia and India together contribute over one-fourth of the total global greenhouse gas emissions from the combustion of fossil-fuels. This paper focuses on the Russian coal-fired power sector, and identifies potential opportunities for reducing emissions. The Russian powe...

Antioxidant activity of selected plant species; potential new sources of natural antioxidants.

PubMed

Nićiforović, N; Mihailović, V; Masković, P; Solujić, S; Stojković, A; Pavlović Muratspahić, D

2010-11-01

The aim of this study was to examine six plants from Serbia for their potential antioxidant activity. Therefore, six antioxidant activity assays were carried out, including: total antioxidant capacity, DPPH free-radical scavenging, the inhibitory activity toward lipid peroxidation, Fe(3+)- reducing power, Fe(2+)- chelating ability and hydroxyl radical scavenging activity. Total phenolic and flavonoid contents were also determined for each alcoholic extract. Cotinus coggygria extract contained the highest amount of total phenols (413mg GAE /g dry extract), while the highest proportion of flavonoids was found in the Echium vulgare methanol extract (105 mg RU/g). Cotinus coggygria and Halacsya sendtneri alcoholic extracts showed the highest total antioxidant capacity (313 and 231 mg AA/g dry extract), as well as DPPH free-radical scavenging (IC(50)=9 and 99 μg/ml), inhibitory activity toward lipid peroxidation (IC(50)=3 and 17 μg/ml) and reducing power. Whereas, the greatest hydroxyl radical scavenging activity, as well as ferrous ion chelating ability showed Echium vulgare, Echium rubrum and Halacsya sendtneri. Copyright © 2010 Elsevier Ltd. All rights reserved.

Evidences of Reduced Antioxidant Activity in Patients With Chronic Migraine and Medication-Overuse Headache.

PubMed

Lucchesi, Cinzia; Baldacci, Filippo; Cafalli, Martina; Chico, Lucia; Lo Gerfo, Annalisa; Bonuccelli, Ubaldo; Siciliano, Gabriele; Gori, Sara

2015-01-01

Migraine is a complex multifactorial, neurobiological disorder, whose pathogenesis is not fully understood, nor are the mechanisms associated with migraine transformation from episodic to chronic pattern. A possible role of impaired oxidative mitochondrial metabolism in migraine pathogenesis has been hypothesized, and increased levels of peripheral markers of oxidative stress have been reported in migraine patients, although the literature data are limited and heterogeneous. The aim of this cross-sectional study was to determine plasmatic levels of advanced oxidation protein products, ferric-reducing antioxidant power and total plasmatic thiol groups, all plasmatic markers related to oxidative stress, in a sample of chronic migraine patients and medication-overuse headache, compared to a control group of healthy subjects. Thirty-three patients with a diagnosis of both chronic migraine and medication-overuse headache (International Classification of Headache Disorders,3rd edition, beta version) and 33 healthy, headache-free subjects were enrolled. Patients with comorbid/coexisting conditions were excluded, as well as patients in treatment with migraine preventive drugs. Plasmatic levels of advanced oxidation protein products, ferric-reducing antioxidant power, and total thiol groups were determined in migraine patients and controls; moreover, oxidative stress biomarkers were compared in migraine patients with triptan compared to non-steroidal anti-inflammatory drug overuse. The statistical analysis showed significantly lower levels of ferric-reducing antioxidant power and total plasmatic thiol groups, both expression of antioxidant power, in patients with chronic migraine and medication-overuse headache compared to controls (respectively, ferric antioxidant power median [interquartile range] 0.53 [0.22] vs 0.82 [0.11] mmol/L, P < .001; total thiol groups 0.25 [0.08] vs 0.51 [0.11] μmol/L, P < .001). Moreover, no statistically significant differences in oxidative stress biomarkers were detected between patients with triptan and nonsteroidal anti-inflammatory drug overuse. The data from the present study suggest that antioxidant capacity is lower in chronic migraine patients and medication-overuse headache compared to healthy headache-free subjects, with no differences between patients with triptan or nonsteroidal anti-inflammatory drug overuse. Further investigation is certainly necessary in order to define the causal or consequential role of an imbalance between pro-oxidants and antioxidant defenses in migraine pathogenesis and "chronification" and the possible therapeutic implications in clinical practice. © 2015 American Headache Society.

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

NASA Astrophysics Data System (ADS)

Tanaka, Suiki; Niitsu, Kiichi; Nakazato, Kazuo

2016-03-01

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

Totally Implantable Wireless Ultrasonic Doppler Blood Flowmeters: Toward Accurate Miniaturized Chronic Monitors.

PubMed

Rothfuss, Michael A; Unadkat, Jignesh V; Gimbel, Michael L; Mickle, Marlin H; Sejdić, Ervin

2017-03-01

Totally implantable wireless ultrasonic blood flowmeters provide direct-access chronic vessel monitoring in hard-to-reach places without using wired bedside monitors or imaging equipment. Although wireless implantable Doppler devices are accurate for most applications, device size and implant lifetime remain vastly underdeveloped. We review past and current approaches to miniaturization and implant lifetime extension for wireless implantable Doppler devices and propose approaches to reduce device size and maximize implant lifetime for the next generation of devices. Additionally, we review current and past approaches to accurate blood flow measurements. This review points toward relying on increased levels of monolithic customization and integration to reduce size. Meanwhile, recommendations to maximize implant lifetime should include alternative sources of power, such as transcutaneous wireless power, that stand to extend lifetime indefinitely. Coupling together the results will pave the way for ultra-miniaturized totally implantable wireless blood flow monitors for truly chronic implantation. Copyright © 2016 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Solar ultraviolet-B radiation increases phenolic content and ferric reducing antioxidant power in Avena sativa.

PubMed

Ruhland, Christopher T; Fogal, Mitchell J; Buyarski, Christopher R; Krna, Matthew A

2007-06-29

We examined the influence of solar ultraviolet-B radiation (UV-B; 280-320 nm) on the maximum photochemical efficiency of photosystem II (F(v)/F(m)), bulk-soluble phenolic concentrations, ferric-reducing antioxidant power (FRAP) and growth of Avena sativa. Treatments involved placing filters on frames over potted plants that reduced levels of biologically effective UV-B by either 71% (reduced UV-B) or by 19% (near-ambient UV-B) over the 52 day experiment (04 July-25 August 2002). Plants growing under near-ambient UV-B had 38% less total biomass than those under reduced UV-B. The reduction in biomass was mainly the result of a 24% lower leaf elongation rate, resulting in shorter leaves and less total leaf area than plants under reduced UV-B. In addition, plants growing under near-ambient UV-B had up to 17% lower F(v)/F(m) values early in the experiment, and this effect declined with plant age. Concentrations of bulk-soluble phenolics and FRAP values were 17 and 24% higher under near-ambient UV-B than under reduced UV-B, respectively. There was a positive relationship between bulk-soluble phenolic concentrations and FRAP values. There were no UV-B effects on concentrations of carotenoids (carotenes + xanthophylls).

Randomized controlled trial of toothbrushing to reduce ventilator-associated pneumonia pathogens and dental plaque in a critical care unit.

PubMed

Needleman, Ian G; Hirsch, Nicholas P; Leemans, Michele; Moles, David R; Wilson, Michael; Ready, Derren R; Ismail, Salim; Ciric, Lena; Shaw, Michael J; Smith, Martin; Garner, Anne; Wilson, Sally

2011-03-01

To investigate the effect of a powered toothbrush on colonization of dental plaque by ventilator-associated pneumonia (VAP)-associated organisms and dental plaque removal. Parallel-arm, single-centre, examiner- and analyst-masked randomized controlled trial. Forty-six adults were recruited within 48 h of admission. Test intervention: powered toothbrush, control intervention: sponge toothette, both used four times per day for 2 min. Groups received 20 ml, 0.2% chlorhexidine mouthwash at each time point. The results showed a low prevalence of respiratory pathogens throughout with no statistically significant differences between groups. A highly statistically significantly greater reduction in dental plaque was produced by the powered toothbrush compared with the control treatment; mean plaque index at day 5, powered toothbrush 0.75 [95% confidence interval (CI) 0.53, 1.00], sponge toothette 1.35 (95% CI 0.95, 1.74), p=0.006. Total bacterial viable count was also highly statistically significantly lower in the test group at day 5; Log(10) mean total bacterial counts: powered toothbrush 5.12 (95% CI 4.60, 5.63), sponge toothette 6.61 (95% CI 5.93, 7.28), p=0.002. Powered toothbrushes are highly effective for plaque removal in intubated patients in a critical unit and should be tested for their potential to reduce VAP incidence and health complications. © 2011 John Wiley & Sons A/S.

Influence of TCSC Devices on Congestion Management in a Deregulated Power System Using Evolutionary Programming Technique

NASA Astrophysics Data System (ADS)

Ananthichristy, A., Dr.; Elanthirayan, R.; Brindha, R., Dr.; Siddhiq, M. S.; Venkatesh, N.; Harshit, M. V.; Nikhilreddy, M.

2018-04-01

Congestion management is one of the technical challenges in power system deregulation. In deregulated electricity market it may always not be possible to dispatch all of the contracted power transactions due to congestion of the transmission corridors. Transmission congestion occurs when there is insufficient transmission capacity to simultaneously accommodate all constraints for transmission of a line. Flexible Alternative Current Transmission System (FACTS) devices can be an alternative to reduce the flows in the heavily loaded lines, resulting in an increased loadability, low system loss, improved stability of the network, reduced cost of production and fulfilled contractual requirement by controlling the power flow in the network. A method to determine the optimal location of FACTS has been suggested based on reduction of total system VAR power losses. The simulation was done on IEEE 14 bus system and results were obtained.

Power Allocation and Outage Probability Analysis for SDN-based Radio Access Networks

NASA Astrophysics Data System (ADS)

Zhao, Yongxu; Chen, Yueyun; Mai, Zhiyuan

2018-01-01

In this paper, performance of Access network Architecture based SDN (Software Defined Network) is analyzed with respect to the power allocation issue. A power allocation scheme PSO-PA (Particle Swarm Optimization-power allocation) algorithm is proposed, the proposed scheme is subjected to constant total power with the objective of minimizing system outage probability. The entire access network resource configuration is controlled by the SDN controller, then it sends the optimized power distribution factor to the base station source node (SN) and the relay node (RN). Simulation results show that the proposed scheme reduces the system outage probability at a low complexity.

In vitro free radical scavenging activity of ethanolic extract of the whole plant of Evolvulus alsinoides (L.) L.

PubMed

Gomathi, Duraisamy; Ravikumar, Ganesan; Kalaiselvi, Manokaran; Vidya, Balasubramaniam; Uma, Chandrasekar

2015-06-01

To identify the free radical scavenging activity of ethanolic extract of Evolvulus alsinoides. The free radical scavenging activity was evaluated by in vitro methods like reducing power assay, total antioxidant activity, 2,2-diphenyl-1-picrylhydrazyl (DPPH) reduction, superoxide radical scavenging activity, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS(+)) scavenging activity, hydroxyl radical scavenging assay, and nitric oxide radical scavenging assay, which were studied by using ascorbic acid as standard. The extract showed significant activities in all antioxidant assays compared with the reference antioxidant ascorbic acid. The total antioxidant activity as well as the reducing power was also found to increase in a dose-dependent manner. Evolvulus alsinoides may act as a chemopreventive agent, providing antioxidant properties and offering effective protection from free radicals.

[Polyphenol content and antioxidant activity of several seeds and nuts].

PubMed

Padilla, F C; Rincón, A M; Bou-Rached, L

2008-09-01

Foods from plant origin not only provide human diet with certain antioxidant vitamins (C, E and beta-carotene), but also a complex mixture of polyphenols, with antioxidant activity. Numerous studies have been focused on the protective and preventing effect of this antioxidant activity on certain degenerative illnesses such as cardiovascular, cancer, and neurological diseases, cataracts and oxidative stress dysfunctions. The objective of this work was to evaluate total polyphenol content and antioxidant activity of several seeds, nuts, or grains such as Theobroma cacao, Canpsiandra comosa Benth (chiga), Sorghum bicolor, L. Moench, Melicoccus bijugatus (genip). Total polyphenol content was assessed by the Folin-Ciocalteau method and the antioxidant activity by the beta carotene/linoleate, reducing power, and the anti-radical activity methods. Results showed genip pericarp with the lowest polyphenol content (1.40 gGAE/100 g), and cacao beans with the highest (6.66 gGAE/100 g). Reducing power of cacao beans was also the highest and similar to the reducing power of 5.80 g ascorbic acid/100 g, followed by Campsiandra comosa. Moreover, Campsiandra comosa and cacao seeds presented an antioxidant activity comparable to that of the butylhydroxianisol, a synthetic antioxidant. The highest anti-radical activity was shown by Campsiandra comosa with an EC50 of 2.67 g/gDPPH. Total polyphenol content shows a good correlation with the antioxidant activity. Moreover, these seeds might have the same health beneficial effects attributed to other fruits and vegetables.

Leg exoskeleton reduces the metabolic cost of human hopping.

PubMed

Grabowski, Alena M; Herr, Hugh M

2009-09-01

During bouncing gaits such as hopping and running, leg muscles generate force to enable elastic energy storage and return primarily from tendons and, thus, demand metabolic energy. In an effort to reduce metabolic demand, we designed two elastic leg exoskeletons that act in parallel with the wearer's legs; one exoskeleton consisted of a multiple leaf (MLE) and the other of a single leaf (SLE) set of fiberglass springs. We hypothesized that hoppers, hopping on both legs, would adjust their leg stiffness while wearing an exoskeleton so that the combination of the hopper and exoskeleton would behave as a linear spring-mass system with the same total stiffness as during normal hopping. We also hypothesized that decreased leg force generation while wearing an exoskeleton would reduce the metabolic power required for hopping. Nine subjects hopped in place at 2.0, 2.2, 2.4, and 2.6 Hz with and without an exoskeleton while we measured ground reaction forces, exoskeletal compression, and metabolic rates. While wearing an exoskeleton, hoppers adjusted their leg stiffness to maintain linear spring-mass mechanics and a total stiffness similar to normal hopping. Without accounting for the added weight of each exoskeleton, wearing the MLE reduced net metabolic power by an average of 6% and wearing the SLE reduced net metabolic power by an average of 24% compared with hopping normally at frequencies between 2.0 and 2.6 Hz. Thus, when hoppers used external parallel springs, they likely decreased the mechanical work performed by the legs and substantially reduced metabolic demand compared with hopping without wearing an exoskeleton.

Seasonal thermoregulatory responses in mammals.

PubMed

Lovegrove, Barry G

2005-05-01

This study examined the proportional seasonal winter adjustments of total and mass-specific basal power (watts and watts g-1, respectively), thermal conductance (watts g-1 degrees C-1), non-shivering thermogenesis capacity (ratio of NST/basal power), body temperature ( degrees C), and body mass (g) of mammals. The responses are best summarized for three different body size classes; small mammals (<100 g), intermediate-sized mammals (0.1-10 kg), and large mammals (>10 kg). The principal adjustments of the small mammals center on energy conservation, especially the Dehnel Effect, the winter reduction in body size of as much as 50%, accompanied by reductions in mass-specific basal power. On average, these reductions reduce the total basal power approximately in direct proportion to the mass reductions. Reductions in mass-specific basal power are matched by concomitant reductions in conductance to maintain the setpoint body temperature during winter. The overall thermoregulatory adjustments in small mammals serve to (a) lower overall winter power consumption, (b) maintain the setpoint body temperature, and (c) lower the lower critical limit of thermoneutrality and hence thermoregulatory costs. In intermediate-size mammals, the seasonal response is centered more on increasing thermogenic capacity by increasing basal power and NST capacity, accompanied by predictable and large reductions in conductance. The Dehnel effect is negligible. Very large mammals undergo the largest reductions in total and mass-specific basal power and conductance. However, there are too few data to resolve whether the reductions in total basal power can be attributed to the Dehnel effect, because the moderate decreases in body mass may also be caused by nutritional stress. Apart from the seasonal changes in basal power, these observations are consistent with the predictions of Heldmaier's seasonal acclimatization model.

Research on Stabilization Properties of Inductive-Capacitive Transducers Based on Hybrid Electromagnetic Elements

NASA Astrophysics Data System (ADS)

Konesev, S. G.; Khazieva, R. T.; Kirllov, R. V.; Konev, A. A.

2017-01-01

Some electrical consumers (the charge system of storage capacitor, powerful pulse generators, electrothermal systems, gas-discharge lamps, electric ovens, plasma torches) require constant power consumption, while their resistance changes in the limited range. Current stabilization systems (CSS) with inductive-capacitive transducers (ICT) provide constant power, when the load resistance changes over a wide range and increaseы the efficiency of high-power loads’ power supplies. ICT elements are selected according to the maximum load, which leads to exceeding a predetermined value of capacity. The paper suggests carrying load power by the ICT based on multifunction integrated electromagnetic components (MIEC) to reduce the predetermined capacity of ICT elements and CSS weights and dimensions. The authors developed and patented ICT based on MIEC that reduces the CSS weights and dimensions by reducing components number with the possibility of device’s electric energy transformation and resonance frequency changing. An ICT mathematical model was produced. The model determines the width of the load stabilization range. Electromagnetic processes study model was built with the MIEC integral parameters (full inductance of the electrical lead, total capacity, current of electrical lead). It shows independence of the load current from the load resistance for different ways of MIEC connection.

Development of Advanced Technologies to Reduce Design, Fabrication and Construction Costs for Future Nuclear Power Plants

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

DiNunzio, Camillo A.; Gupta, Abhinav; Golay, Michael

2002-11-30

This report presents a summation of the third and final year of a three-year investigation into methods and technologies for substantially reducing the capital costs and total schedule for future nuclear plants. In addition, this is the final technical report for the three-year period of studies.

NASA Growth Space Station missions and candidate nuclear/solar power systems

NASA Technical Reports Server (NTRS)

Heller, Jack A.; Nainiger, Joseph J.

1987-01-01

A brief summary is presented of a NASA study contract and in-house investigation on Growth Space Station missions and appropriate nuclear and solar space electric power systems. By the year 2000 some 300 kWe will be needed for missions and housekeeping power for a 12 to 18 person Station crew. Several Space Station configurations employing nuclear reactor power systems are discussed, including shielding requirements and power transmission schemes. Advantages of reactor power include a greatly simplified Station orientation procedure, greatly reduced occultation of views of the earth and deep space, near elimination of energy storage requirements, and significantly reduced station-keeping propellant mass due to very low drag of the reactor power system. The in-house studies of viable alternative Growth Space Station power systems showed that at 300 kWe a rigid silicon solar cell array with NiCd batteries had the highest specific mass at 275 kg/kWe, with solar Stirling the lowest at 40 kg/kWe. However, when 10 year propellant mass requirements are factored in, the 300 kWe nuclear Stirling exhibits the lowest total mass.

Antioxidant activities of Lampaya medicinalis extracts and their main chemical constituents

PubMed Central

2014-01-01

Background Lampaya medicinalis Phil. (Verbenaceae) is a plant used by Aymara and Quechua ethnic groups from Northern Chile as folk medicine in the treatment and cure of various diseases. The aim of this study was to investigate the in vitro antioxidant activity, total phenols content, total flavonoids content, total antioxidant activity, reducing power, brine shrimp cytotoxicity and identify the principal chemical constituents. Methods The crude hydroethanolic extract (HEE) and its partitioned fraction: hexane (HF), dichloromethane (DF), ethyl acetate (EAF), n-butanol (BF) and soluble residual aqueous fraction (RWF) were evaluated for their antioxidant activity using different assays namely, DPPH, ABTS, FRAP, β-carotene bleaching assay. The content of total phenolics and total flavonoids were measured by Folin-Ciocalteau and by the AlCl3 colorimetric method, respectively. Reducing power was determined by phosphomolybdate and hexacyanoferrate (III) methods. Biotoxicity assays were performed on shrimps of Artemia salina. The EAF was fractionated using chromatographic methods. Results Considerable amount of phenolic and flavonoid contents were recorded in the hydroethanolic extract (HEE) and its derived fractions. Although HEE and all its derived fractions exhibited good antioxidant activities, the most distinguished radical scavenging potential was observed for ethyl acetate fraction (EAF). EAF showed the higher radical scavenging activity by DPPH (95%) and by ABTS (98%), antioxidant activity by FRAP (158.18 ± 5.79 mg equivalent Trolox/g fraction), β-carotene bleaching assay (86.8%), the highest total phenols content (101.26 ± 1.07 mg GAE/g fraction), the highest total flavonoids content (66.26 ± 3.31 μg quercetin/g fraction). The EAF extract showed an reducing power of 78% and 65% using the phosphomolybdate and hexacyanoferrate (III) assays, respectively. Four flavonoids, two p-hydroxyacetophenone derivatives and one iridoid were isolated from Lampaya medicinalis for the first time. Conclusion EtOAc soluble fraction (EAF) shows the strongest antioxidant activity, and it can be attributed to its high content in phenolic and flavonoid compounds. It can be concluded that L.medicinalis can be used as an effective natural source of antioxidant, as ethnomedicine and as a commercial basis for the development of nutraceuticals. PMID:25047047

Energy conservation strategy in Hydraulic Power Packs using Variable Frequency Drive IOP Conference Series: Materials Science and Engineering

NASA Astrophysics Data System (ADS)

Ramesh, S.; Ashok, S. Denis; Nagaraj, Shanmukha; Reddy, M. Lohith Kumar; Naulakha, Niranjan Kumar; Adithyakumar, C. R.

2018-02-01

At present, energy consumption is to such an extent that if the same trend goes on then in the future at some point of time, the energy sources will all be exploited. Energy conservation in a hydraulic power pack refers to the reduction in the energy consumed by the power pack. Many experiments have been conducted to reduce the energy consumption and one of those methods is by introducing a variable frequency drive. The main objective of the present work is to reduce the energy consumed by the hydraulic power pack using variable frequency drive. Variable Frequency drive is used to vary the speed of the motor by receiving electrical signals from the pressure switch which acts as the feedback system. Using this concept, the speed of the motor can be varied between the specified limits. In the present work, a basic hydraulic power pack and a variable frequency drive based hydraulic power pack were designed and compared both of them with the results obtained. The comparison was based on the power consumed, rise in temperature, noise levels, and flow of oil through pressure relief valve, total oil flow during loading cycle. By comparing both the circuits, it is found that for the proposed system, consumption of power reduces by 78.4% and is as powerful as the present system.

Changes in antioxidant and biochemical activities in castor oil-coated Capsicum annuum L. during postharvest storage.

PubMed

Panigrahi, Jitendriya; Patel, Mansi; Patel, Niyati; Gheewala, Bhumi; Gantait, Saikat

2018-06-01

This study, for the first time, evaluates the efficiency of castor oil when used as an external coating on Capsicum annuum L., to increase postharvest storage-life at 4 ± 1 °C. The castor oil-coated fruits were successfully stored for 36 days, while the non-coated fruits could only sustain for 18 days. Throughout the storage period (at 9-day intervals), different antioxidants and biochemical assays (allied with storage) such as titratable acidity, ascorbic acid content, ferrous ion chelating activity, reducing power, DPPH scavenging activity, hydroxyl radical scavenging activity, total phenolic content, total sugar estimation, and enzymatic study of polyphenol oxidase and pectate lyase, were assessed. During storage, the castor oil-coated fruits showed a substantial decrease in titratable acidity, ascorbic acid content, total phenolic content, including antioxidant activities such as reducing power and DPPH activity; however, an increase in ferrous ion chelating activity, total soluble sugar content, polyphenol oxidase activity and initial pectate lyase activity was observed, in contrast to that of the non-coated fruits. The application of castor oil proved to be effective in delaying the ripening process of fruits during storage.

Automated selective disruption of slow wave sleep.

PubMed

Ooms, Sharon J; Zempel, John M; Holtzman, David M; Ju, Yo-El S

2017-04-01

Slow wave sleep (SWS) plays an important role in neurophysiologic restoration. Experimentally testing the effect of SWS disruption previously required highly time-intensive and subjective methods. Our goal was to develop an automated and objective protocol to reduce SWS without affecting sleep architecture. We developed a custom Matlab™ protocol to calculate electroencephalogram spectral power every 10s live during a polysomnogram, exclude artifact, and, if measurements met criteria for SWS, deliver increasingly louder tones through earphones. Middle-aged healthy volunteers (n=10) each underwent 2 polysomnograms, one with the SWS disruption protocol and one with sham condition. The SWS disruption protocol reduced SWS compared to sham condition, as measured by spectral power in the delta (0.5-4Hz) band, particularly in the 0.5-2Hz range (mean 20% decrease). A compensatory increase in the proportion of total spectral power in the theta (4-8Hz) and alpha (8-12Hz) bands was seen, but otherwise normal sleep features were preserved. N3 sleep decreased from 20±34 to 3±6min, otherwise there were no significant changes in total sleep time, sleep efficiency, or other macrostructural sleep characteristics. This novel SWS disruption protocol produces specific reductions in delta band power similar to existing methods, but has the advantage of being automated, such that SWS disruption can be performed easily in a highly standardized and operator-independent manner. This automated SWS disruption protocol effectively reduces SWS without impacting overall sleep architecture. Copyright © 2017 Elsevier B.V. All rights reserved.

Power Management in Regenerative Life Support Systems

NASA Technical Reports Server (NTRS)

Crawford, Sekou; Pawlowski, Christopher; Finn, Cory; Mead, Susan C. (Technical Monitor)

1999-01-01

Effective management of power can reduce the cost of launch and operation of regenerative life support systems. Variations in power may be quite severe and may manifest as surges or spikes, While the power plant may have some ability to deal with these variations, with batteries for example, over-capacity is expensive and does nothing to address the fundamental issue of excessive demand. Because the power unit must be sized to accommodate the largest demand, avoiding power spikes has the potential to reduce the required size of the power plant while at the same time increasing the dependability of the system. Scheduling of processors can help to reduce potential power spikes. However, not all power-consuming equipment is easily scheduled. Therefore, active power management is needed to further decrease the risk of surges or spikes. We investigate the use of a hierarchical scheme to actively manage power for a model of a regenerative life support system. Local level controllers individually determine subsystem power usage. A higher level controller monitors overall system power and detects surges or spikes. When a surge condition is detected, the higher level controller conducts an 'auction' and describes subsystem power usage to re-allocate power. The result is an overall reduction in total power during a power surge. The auction involves each subsystem making a 'bid' to buy or sell power based on local needs. However, this re-allocation cannot come at the expense of life support function. To this end, participation in the auction is restricted to those processes meeting certain tolerance constraints. These tolerances represent acceptable limits within which system processes can be operated. We present a simulation model and discuss some of our results.

A New Approach to Design of an optimized Grid Tied Smart Solar Photovoltaic (PV) System

NASA Astrophysics Data System (ADS)

Farhad, M. Mehedi; Ali, M. Mohammad; Iqbal, M. Asif; Islam, N. Nahar; Ashraf, N.

2012-11-01

Energy is the key element for the economical development of a country. With the increasing concern about the global demand for Renewable Energy (RE) energy, it is very much important to reduce the cost of the whole solar photovoltaic (PV) system. Still now most of the solar photovoltaic (PV) system is highly expensive. In this paper we have shown that grid tied solar system can be developed by omitting the energy storage device like large capacity battery bank. It will not only reduce the internallosses for charging and discharging of battery bank but also at the same time a large amount of cost of the battery will be reduced. So, the system maintenance cost will be reduced also. We have proposed a new approach to design a photovoltaic (PV) solar power system which can be operated by feeding the solar power to the national grid along with the residential load. Again if there is an extra power demand for residential load along with the solar power then this system can also provide an opportunity to consume the power from the national grid. The total system is controlled with the help of some the sensors and a microcontroller. As a whole a significant reduction in the system costs and efficient system performance can be realized.

Nutraceutical composition of Zizyphus mauritiana Lamk (Indian ber): effect of enzyme-assisted processing.

PubMed

Koley, Tanmay Kumar; Walia, Shweta; Nath, Prerna; Awasthi, O P; Kaur, Charanjit

2011-05-01

Zizyphus (Indian ber) is an excellent source of several phenolic compounds. The effect of two cell wall degrading enzymes, namely pectinase and viscozyme, on the nutraceutical composition of Zizyphus juice was investigated in the present study. Enzyme assisted processing significantly (P < 0.05) improved the juice yield, total soluble solids, total phenolics and total antioxidant activity (AOX). There was significant increase in recovery of antioxidants, to the tune of 70.51%, 66%, and 45% respectively in ascorbic acid, total phenolics and total flavonoids through viscozyme. The in-vitro total AOX of juice extracted via enzyme-assisted processing was 20.9 and 15.59 μmol Trolox/ml in ferric-reducing antioxidant power and cupric-reducing antioxidant capacity assays, respectively. There was 41% increase in AOX of juice extracted with enzyme over straight pressed juice. Results indicate that enzyme-assisted processing can significantly improve the functional properties of the Zizyphus juice.

Engineering innovation to reduce wind power COE

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

Ammerman, Curtt Nelson

There are enough wind resources in the US to provide 10 times the electric power we currently use, however wind power only accounts for 2% of our total electricity production. One of the main limitations to wind use is cost. Wind power currently costs 5-to-8 cents per kilowatt-hour, which is more than twice the cost of electricity generated by burning coal. Our Intelligent Wind Turbine LDRD Project is applying LANL's leading-edge engineering expertise in modeling and simulation, experimental validation, and advanced sensing technologies to challenges faced in the design and operation of modern wind turbines.

Optimal Dynamic Sub-Threshold Technique for Extreme Low Power Consumption for VLSI

NASA Technical Reports Server (NTRS)

Duong, Tuan A.

2012-01-01

For miniaturization of electronics systems, power consumption plays a key role in the realm of constraints. Considering the very large scale integration (VLSI) design aspect, as transistor feature size is decreased to 50 nm and below, there is sizable increase in the number of transistors as more functional building blocks are embedded in the same chip. However, the consequent increase in power consumption (dynamic and leakage) will serve as a key constraint to inhibit the advantages of transistor feature size reduction. Power consumption can be reduced by minimizing the voltage supply (for dynamic power consumption) and/or increasing threshold voltage (V(sub th), for reducing leakage power). When the feature size of the transistor is reduced, supply voltage (V(sub dd)) and threshold voltage (V(sub th)) are also reduced accordingly; then, the leakage current becomes a bigger factor of the total power consumption. To maintain low power consumption, operation of electronics at sub-threshold levels can be a potentially strong contender; however, there are two obstacles to be faced: more leakage current per transistor will cause more leakage power consumption, and slow response time when the transistor is operated in weak inversion region. To enable low power consumption and yet obtain high performance, the CMOS (complementary metal oxide semiconductor) transistor as a basic element is viewed and controlled as a four-terminal device: source, drain, gate, and body, as differentiated from the traditional approach with three terminals: i.e., source and body, drain, and gate. This technique features multiple voltage sources to supply the dynamic control, and uses dynamic control to enable low-threshold voltage when the channel (N or P) is active, for speed response enhancement and high threshold voltage, and when the transistor channel (N or P) is inactive, to reduce the leakage current for low-leakage power consumption.

Transient thermal characteristics of high-temperature SiC power module enhanced with Al-bump technology

NASA Astrophysics Data System (ADS)

Tanisawa, Hidekazu; Kato, Fumiki; Koui, Kenichi; Sato, Shinji; Watanabe, Kinuyo; Takahashi, Hiroki; Murakami, Yoshinori; Sato, Hiroshi

2018-04-01

In this paper, we demonstrate a mounting technology that improves the tolerance to transient power loss by adding a heat capacity near the device. Silicon carbide (SiC) power devices can operate at high temperatures, up to 250 °C, at which silicon (Si) power devices cannot. Therefore, it is possible to allow a large temperature difference between the device and ambient air. Thus, the size of a power converter equipped with an SiC power module is reduced by simplifying the cooling system. The temperature of the power module is important not only in the steady state, but in transient loads as well. Therefore, we developed the Al-bump flip-chip mounting technology to increase heat capacity near the device. With this proposed structure, the heat capacity per device increased by 1.7% compared with the total heat capacity of the conventional structure using wire bonding. The reduction in transient thermal impedance is observed from 0.003 to 3 s, and we confirmed that the transient thermal impedance is reduced very efficiently by 15% at the maximum, compared with the conventional structure.

Economic analysis of the design and fabrication of a space qualified power system

NASA Technical Reports Server (NTRS)

Ruselowski, G.

1980-01-01

An economic analysis was performed to determine the cost of the design and fabrication of a low Earth orbit, 2 kW photovoltaic/battery, space qualified power system. A commercially available computer program called PRICE (programmed review of information for costing and evaluation) was used to conduct the analysis. The sensitivity of the various cost factors to the assumptions used is discussed. Total cost of the power system was found to be $2.46 million with the solar array accounting for 70.5%. Using the assumption that the prototype becomes the flight system, 77.3% of the total cost is associated with manufacturing. Results will be used to establish whether the cost of space qualified hardware can be reduced by the incorporation of commercial design, fabrication, and quality assurance methods.

Life cycle assessment of coal-fired power plants and sensitivity analysis of CO2 emissions from power generation side

NASA Astrophysics Data System (ADS)

Yin, Libao; Liao, Yanfen; Zhou, Lianjie; Wang, Zhao; Ma, Xiaoqian

2017-05-01

The life cycle assessment and environmental impacts of a 1000MW coal-fired power plant were carried out in this paper. The results showed that the operation energy consumption and pollutant emission of the power plant are the highest in all sub-process, which accounts for 93.93% of the total energy consumption and 92.20% of the total emission. Compared to other pollutant emissions from the coal-fired power plant, CO2 reached up to 99.28%. Therefore, the control of CO2 emission from the coal-fired power plants was very important. Based on the BP neural network, the amount of CO2 emission from the generation side of coal-fired power plants was calculated via carbon balance method. The results showed that unit capacity, coal quality and unit operation load had great influence on the CO2 emission from coal-fired power plants in Guangdong Province. The use of high volatile and high heat value of coal also can reduce the CO2 emissions. What’s more, under higher operation load condition, the CO2 emissions of 1 kWh electric energy was less.

A Total Cost of Ownership Model for Low Temperature PEM Fuel Cells in Combined Heat and Power and Backup Power Applications

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

University of California, Berkeley; Wei, Max; Lipman, Timothy

2014-06-23

A total cost of ownership model is described for low temperature proton exchange membrane stationary fuel cell systems for combined heat and power (CHP) applications from 1-250kW and backup power applications from 1-50kW. System designs and functional specifications for these two applications were developed across the range of system power levels. Bottom-up cost estimates were made for balance of plant costs, and detailed direct cost estimates for key fuel cell stack components were derived using design-for-manufacturing-and-assembly techniques. The development of high throughput, automated processes achieving high yield are projected to reduce the cost for fuel cell stacks to the $300/kWmore » level at an annual production volume of 100 MW. Several promising combinations of building types and geographical location in the U.S. were identified for installation of fuel cell CHP systems based on the LBNL modelling tool DER CAM. Life-cycle modelling and externality assessment were done for hotels and hospitals. Reduced electricity demand charges, heating credits and carbon credits can reduce the effective cost of electricity ($/kWhe) by 26-44percent in locations such as Minneapolis, where high carbon intensity electricity from the grid is displaces by a fuel cell system operating on reformate fuel. This project extends the scope of existing cost studies to include externalities and ancillary financial benefits and thus provides a more comprehensive picture of fuel cell system benefits, consistent with a policy and incentive environment that increasingly values these ancillary benefits. The project provides a critical, new modelling capacity and should aid a broad range of policy makers in assessing the integrated costs and benefits of fuel cell systems versus other distributed generation technologies.« less

High-temperature superconductors for space power transmission lines

NASA Astrophysics Data System (ADS)

Hull, John R.; Myers, Ira T.

1989-08-01

Analysis of high temperature superconductors (HTS) for space power transmission lines shows that they have the potential to provide low weight alternatives to conventional power distribution systems, especially for line lengths greater than 100 m. The use of directional radiators, combined with the natural vacuum of space, offers the possibility of reducing or eliminating the heat flux from the environment that dominates loss in terrestrial systems. This leads to scaling laws that favor flat conductor geometries. From a total launch weight viewpoint, HTS transmission lines appear superior, even with presently attainable values of current density.

Antioxidant, analgesic and anti-inflammatory activities of the methanolic extract of Piper betle leaves.

PubMed

Alam, Badrul; Akter, Fahima; Parvin, Nahida; Sharmin Pia, Rashna; Akter, Sharmin; Chowdhury, Jesmin; Sifath-E-Jahan, Kazi; Haque, Ekramul

2013-01-01

The present study was designed to evaluate the antioxidant, analgesic, and anti-inflammatory activities of the methanolic extract of Piper betle leaves (MPBL). MPBL was evaluated for anti-inflammatory activity using carrageenan-induced hind paw edema model. Analgesic activity of MPBL was evaluated by hot plate, writhing, and formalin tests. Total phenolic and flavonoids content, total antioxidant activity, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, peroxynitrate (ONOO) as well as inhibition of total ROS generation, and assessment of reducing power were used to evaluate antioxidant potential of MPBL. The extract of MPBL, at the dose of 100 and 200 mg/kg, produced a significant (p<0.05) increase in pain threshold in hot plate method whereas significantly (p<0.05) reduced the writhing caused by acetic acid and the number of licks induced by formalin in a dose-dependent manner. The same ranges of doses of MPBL caused significant (p<0.05) inhibition of carrageenan-induced paw edema after 4 h in a dose-dependent manner. In DPPH, ONOO(-), and total ROS scavenging method, MPBL showed good antioxidant potentiality with the IC50 value of 16.33±1.02, 25.16±0.61 , and 41.72±0.48 µg/ml, respectively with a significant (p<0.05) good reducing power. The findings of the study suggested that MPBL has strong analgesic, anti-inflammatory, and antioxidant effects, conforming the traditional use of this plant for inflammatory pain alleviation to its antioxidant potentiality.

Evaluation of parasitic consumption for a CSP plant

NASA Astrophysics Data System (ADS)

Ramorakane, Relebohile John; Dinter, Frank

2016-05-01

With the continuous development and desire to build alternative effective and efficient power plants, Concentrated Solar Power (CSP) plants (and more specifically the Parabolic Trough CSP Plants) have proven to be one of the alternative energy resources for the future. On this regard more emphasis and research is being employed to better this power plant technology, where one of the main challenges to these plants is to improve their efficiency by optimizing the parasitic load, wherein one of the major causes of the power plants' reduced overall efficiency arises from their parasitic load consumption. This project is therefore aimed at evaluating the parasitic load on Andasol 3 Power Plant, which is a 50 MW Parabolic Trough Power Plant with a 7.5 hours of full load storage system. It was hence determined that the total power plant's parasitic load consumption is about 12% in summer season and between 16% and 24% in winter season. In an effort to improve the power plant's efficiency, a couple of measures to reduce the parasitic load consumption were recommended, and also an alternative and cheaper source of parasitic load feeding plant, during the day (when the parasitic load consumption is highest) was proposed/recommended.

Space transportation system options for extended duration and power

NASA Technical Reports Server (NTRS)

Loftus, J. P., Jr.

1979-01-01

A modification kit for the Space Transportation System (STS) Orbiter is proposed to provide more power and mission duration for payloads. The power extension package (PEP) - a flexible-substrate solar array deployed on the Space Shuttle Orbiter remote manipulator system - can provide as much as 29 kW total power for durations of 10 to 48 days. The kit is installed only for those flights which require enhanced power or duration. Modifications to the Orbiter thermal control and life support systems to improve heat balance and to reduce consumables are proposed. The changes consist of repositioning the Orbiter forward radiators and replacing the lithium hydroxide scrubber with a regenerable solid amine.

The antioxidant activitives of mango peel among different cultivars

NASA Astrophysics Data System (ADS)

Liu, Yu-Ge; Zhang, Xiu-Mei; Ma, Fei-Yue; Fu, Qiong

2017-04-01

In this paper, the contents of total phenol and total flavonoid of 8 mango cultivars were determined. Their antioxidant abilities were also evaluated by 1,1-diphenyl-2-pireyhydrazyl (DPPH) radical scavenging, trolox equivalent antioxidant capacity (TEAC) and ferric reducing antioxidant power (FRAP). Correlations between total phenol, total flavonoid and FRAP as well as TEAC were also analyzed. Results showed that mango peels were rich in natural antioxidant compounds the antioxidant abilities were different among different cultivars. The correlations between total phenol, total flavonoid and FRAP indicated phenolics represent a major part of antioxidant capacity in mango peels. This was also useful in the utilization of mango processing waste.

Variation in contents of total phenolics and flavonoids and antioxidant activities in the leaves of 11 Eriobotrya species.

PubMed

Hong, Yanping; Lin, Shunquan; Jiang, Yueming; Ashraf, Muhammad

2008-12-01

Eriobotrya plants are known to have significant amounts of phenolics and flavonoids, and exhibit a strong antioxidant activity. Experiments were conducted to examine variation in the contents of total phenolics and flavonoids, and antioxidant activities in the leaves of 11 Eriobotrya species (Tibet loquat, Daduhe loquat, Hengchun loquat, Taiwan loquat, Oak leaf loquat, Bengal loquat, Fragrant loquat, Guangxi loquat, Obovate loquat, Big flower loquat, and common loquat, the last species include two materials, one is a cultivar 'Zaozhong 6', another is a wild tree). In these species, 'Zaozhong 6' loquat is a cultivar. The leaf extracts of 'Tibet', 'Obovate', 'Taiwan', 'Bengal' and 'Hengchun' loquats exhibited significantly higher contents of total flavonoids and total phenolics, compared with those of other species. Of these 11 species, the highest contents of total phenolics and total flavonoids were observed in 'Tibet' and 'Obovatae' loquats, respectively. The significantly stronger antioxidant abilities assessed by the DPPH radical scavenging activity and reducing power were obtained in the leaf extracts of 'Taiwan', 'Tibet', 'Bengal', 'Oak leaf', 'Hengchun' and 'Obovate' loquats, compared with the other species. In addition, significant correlations were found between the contents of total phenolics or flavonoids and DPPH radical scavenging activity/reducing power. This work indicates that the leaf extracts of the wild Eriobotrya species, 'Tibet', 'Obovatae', 'Taiwan', 'Bengal', 'Oak leaf' and 'Hengchun' loquats, exhibited significantly higher levels of total phenolics and flavonoids, and significantly stronger antioxidant activities, compared with the cultivated species, 'Zaozhong 6' loquat, which suggests that these wild species have a better utilization value.

Optimal Congestion Management in Electricity Market Using Particle Swarm Optimization with Time Varying Acceleration Coefficients

NASA Astrophysics Data System (ADS)

Boonyaritdachochai, Panida; Boonchuay, Chanwit; Ongsakul, Weerakorn

2010-06-01

This paper proposes an optimal power redispatching approach for congestion management in deregulated electricity market. Generator sensitivity is considered to indicate the redispatched generators. It can reduce the number of participating generators. The power adjustment cost and total redispatched power are minimized by particle swarm optimization with time varying acceleration coefficients (PSO-TVAC). The IEEE 30-bus and IEEE 118-bus systems are used to illustrate the proposed approach. Test results show that the proposed optimization scheme provides the lowest adjustment cost and redispatched power compared to the other schemes. The proposed approach is useful for the system operator to manage the transmission congestion.

Remotely Powered Reconfigurable Receiver for Extreme Environment Sensing Platforms

NASA Technical Reports Server (NTRS)

Sheldon, Douglas J.

2012-01-01

Wireless sensors connected in a local network offer revolutionary exploration capabilities, but the current solutions do not work in extreme environments of low temperatures (200K) and low to moderate radiation levels (<50 krad). These sensors (temperature, radiation, infrared, etc.) would need to operate outside the spacecraft/ lander and be totally independent of power from the spacecraft/lander. Flash memory field-programmable gate arrays (FPGAs) are being used as the main signal processing and protocol generation platform in a new receiver. Flash-based FPGAs have been shown to have at least 100 reduced standby power and 10 reduction operating power when compared to normal SRAM-based FPGA technology.

Antioxidant and analgesic activities of turpentine of Pinus nigra Arn. subsp. pallsiana (Lamb.) Holmboe.

PubMed

Gülçin, Ilhami; Büyükokuroglu, M Emin; Oktay, Münir; Küfrevioglu, O Irfan

2003-05-01

The aim of this study is to examine possible antioxidant and analgesic activities of turpentine exudes from Pinus nigra Arn. subsp. pallsiana (Lamb.) Holmboe (TPN). Total antioxidant activity, reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities were studied. The total antioxidant activity increased with the increasing amount of extracts (100, 300, and 500 microg) added to linoleic acid emulsion. All of the doses of TPN showed higher antioxidant activity than alpha-tocopherol. The samples showed 49, 70, and 91% inhibition on peroxidation of linoleic acid emulsion, respectively. On the other hand, the 300 microg of alpha-tocopherol showed 40% inhibition on peroxidation of linoleic acid emulsion. There is correlation between antioxidant activity and the reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities. Like antioxidant activity, the reducing power, superoxide anion radical scavenging, free radical scavenging, metal chelating, and hydrogen peroxide scavenging activities of TPN depending on concentration and increasing with increased concentration of TPN. These properties may be the major reasons for the inhibition of lipid peroxidation. The results obtained in the present study indicate that the TPN has a potential source of natural antioxidant. In addition, analgesic effect of TPN was investigated in present study and TPN had strong analgesic effect. The analgesic effect of TPN compared with metamizol as a standard analgesic compound.

Comparative assessment on in vitro antioxidant activities of ethanol extracts of Averrhoa bilimbi, Gymnema sylvestre and Capsicum frutescens.

PubMed

Rahman, Md Mominur; Habib, Md Razibul; Hasan, Md Anayet; Al Amin, Mohammad; Saha, Ayan; Mannan, Adnan

2014-01-01

Averrhoa bilimbi, Gymnema sylvestre and Capsicum frutescens are medicinal plants commonly used as traditional medicine for the treatment of various diseases. The present study was designed to investigate the antioxidant activities of Ethanolic extract of A. bilimbi, G. sylvestre and C. frutescens. The antioxidant activity of the extracts were evaluated using total phenolic and flavonoid contents, ferric reducing power and the free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH). Total phenolic and flavonoid contents were higher in G. sylvestre (53.63636 ± 0.454545 mg/g gallic acid equivalent) and C. frutescens (26.66667 ± 2.081666 mg/g quercetin equivalent) respectively. Reducing power of the crude ethanol extracts increased with the concentrations of the extracts and all the extracts showed moderate free radical scavenging activity against DPPH. The plant extract displayed moderate phenolic and flavonoid contents compared to gallic acid and quercetin equivalent respectively, whereas also exhibited significant scavenging of DPPH radical and reducing power compared with ascorbic acid as standard. Our study suggests that G. sylvestre has significant antioxidant activity. The antioxidant compound of this plant might be a therapeutic candidate against oxidative stress related diseases. Different sub-fraction of A. bilimbi and C. frutescens should be studied further to assess the effect. Further study is necessary for isolation and characterization of the active antioxidant agents for better treatment.

The independent effects of speed and propulsive force on joint power generation in walking

PubMed Central

Browne, Michael G.; Franz, Jason R.

2017-01-01

Walking speed is modulated using propulsive forces (FP) during push-off and both preferred speed and FP decrease with aging. However, even prior to walking slower, reduced FP may be accompanied by potentially unfavorable changes in joint power generation. For example, compared to young adults, older adults exhibit a redistribution of mechanical power generation from the propulsive plantarflexor muscles to more proximal muscles acting across the knee and hip. Here, we used visual biofeedback based on real-time FP measurements to decouple and investigate the interaction between joint-level coordination, whole-body FP, and walking speed. 12 healthy young subjects walked on a dual-belt instrumented treadmill at a range of speeds (0.9 – 1.3 m/s). We immediately calculated the average FP from each speed. Subjects then walked at 1.3 m/s while completing a series of biofeedback trials with instructions to match their instantaneous FP to their averaged FP from slower speeds. Walking slower decreased FP and total positive joint work with little effect on relative joint-level contributions. Conversely, subjects walked at a constant speed with reduced FP, not by reducing total positive joint work, but by redistributing the mechanical demands of each step from the plantarflexor muscles during push-off to more proximal leg muscles during single support. Interestingly, these naturally emergent joint- and limb-level biomechanical changes, in the absence of neuromuscular constraints, resemble those due to aging. Our findings provide important reference data to understand the presumably complex interactions between joint power generation, whole-body FP, and walking speed in our aging population. PMID:28262285

Automated selective disruption of slow wave sleep

PubMed Central

Ooms, Sharon J.; Zempel, John M.; Holtzman, David M.; Ju, Yo-El S.

2017-01-01

Background Slow wave sleep (SWS) plays an important role in neurophysiologic restoration. Experimentally testing the effect of SWS disruption previously required highly time-intensive and subjective methods. Our goal was to develop an automated and objective protocol to reduce SWS without affecting sleep architecture. New Method We developed a custom Matlab™ protocol to calculate electroencephalogram spectral power every 10 seconds live during a polysomnogram, exclude artifact, and, if measurements met criteria for SWS, deliver increasingly louder tones through earphones. Middle-aged healthy volunteers (n=10) each underwent 2 polysomnograms, one with the SWS disruption protocol and one with sham condition. Results The SWS disruption protocol reduced SWS compared to sham condition, as measured by spectral power in the delta (0.5–4 Hz) band, particularly in the 0.5–2 Hz range (mean 20% decrease). A compensatory increase in the proportion of total spectral power in the theta (4–8 Hz) and alpha (8–12 Hz) bands was seen, but otherwise normal sleep features were preserved. N3 sleep decreased from 20±34 to 3±6 minutes, otherwise there were no significant changes in total sleep time, sleep efficiency, or other macrostructural sleep characteristics. Comparison with existing method This novel SWS disruption protocol produces specific reductions in delta band power similar to existing methods, but has the advantage of being automated, such that SWS disruption can be performed easily in a highly standardized and operator-independent manner. Conclusion This automated SWS disruption protocol effectively reduces SWS without impacting overall sleep architecture. PMID:28238859

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

Komiyama, Ryoichi; Marnay, Chris; Stadler, Michael

In this analysis, the authors projected Japan's energy demand/supply and energy-related CO{sub 2} emissions to 2050. Their analysis of various scenarios indicated that Japan's CO{sub 2} emissions in 2050 could be potentially reduced by 26-58% from the current level (FY 2005). These results suggest that Japan could set a CO{sub 2} emission reduction target for 2050 at between 30% and 60%. In order to reduce CO{sub 2} emissions by 60% in 2050 from the present level, Japan will have to strongly promote energy conservation at the same pace as an annual rate of 1.9% after the oil crises (to cutmore » primary energy demand per GDP (TPES/GDP) in 2050 by 60% from 2005) and expand the share of non-fossil energy sources in total primary energy supply in 2050 to 50% (to reduce CO{sub 2} emissions per primary energy demand (CO{sub 2}/TPES) in 2050 by 40% from 2005). Concerning power generation mix in 2050, nuclear power will account for 60%, solar and other renewable energy sources for 20%, hydro power for 10% and fossil-fired generation for 10%, indicating substantial shift away from fossil fuel in electric power supply. Among the mitigation measures in the case of reducing CO{sub 2} emissions by 60% in 2050, energy conservation will make the greatest contribution to the emission reduction, being followed by solar power, nuclear power and other renewable energy sources. In order to realize this massive CO{sub 2} abatement, however, Japan will have to overcome technological and economic challenges including the large-scale deployment of nuclear power and renewable technologies.« less

How Virtual Technology Can Impact Total Ownership Costs on a USN Vessel

DTIC Science & Technology

2012-03-01

Clients (After Lam, 2010) Alternative Solutions Labor $M Hardware $M Software $M Transport $M Power & Cooling $M Virtualization $M...and will hold contractors accountable to ensure energy efficiency targets of new equipment are as advertised . 2. Total Cost of Ownership...automatically placed into Standby by the VMware software and reduced energy consumption by 230 watts. Even though there were 12 virtual desktops online and in

Advanced Hydrogen Liquefaction Process

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

Schwartz, Joseph; Kromer, Brian; Neu, Ben

2011-09-28

The project identified and quantified ways to reduce the cost of hydrogen liquefaction, and reduce the cost of hydrogen distribution. The goal was to reduce the power consumption by 20% and then to reduce the capital cost. Optimizing the process, improving process equipment, and improving ortho-para conversion significantly reduced the power consumption of liquefaction, but by less than 20%. Because the efficiency improvement was less than the target, the program was stopped before the capital cost was addressed. These efficiency improvements could provide a benefit to the public to improve the design of future hydrogen liquefiers. The project increased themore » understanding of hydrogen liquefaction by modeling different processes and thoroughly examining ortho-para separation and conversion. The process modeling provided a benefit to the public because the project incorporated para hydrogen into the process modeling software, so liquefaction processes can be modeled more accurately than using only normal hydrogen. Adding catalyst to the first heat exchanger, a simple method to reduce liquefaction power, was identified, analyzed, and quantified. The demonstrated performance of ortho-para separation is sufficient for at least one identified process concept to show reduced power cost when compared to hydrogen liquefaction processes using conventional ortho-para conversion. The impact of improved ortho-para conversion can be significant because ortho para conversion uses about 20-25% of the total liquefaction power, but performance improvement is necessary to realize a substantial benefit. Most of the energy used in liquefaction is for gas compression. Improvements in hydrogen compression will have a significant impact on overall liquefier efficiency. Improvements to turbines, heat exchangers, and other process equipment will have less impact.« less

Development of an Agent Based Model to Estimate and Reduce Time to Restoration of Storm Induced Power Outages

NASA Astrophysics Data System (ADS)

Walsh, T.; Layton, T.; Mellor, J. E.

2017-12-01

Storm damage to the electric grid impacts 23 million electric utility customers and costs US consumers $119 billion annually. Current restoration techniques rely on the past experiences of emergency managers. There are few analytical simulation and prediction tools available for utility managers to optimize storm recovery and decrease consumer cost, lost revenue and restoration time. We developed an agent based model (ABM) for storm recovery in Connecticut. An ABM is a computer modeling technique comprised of agents who are given certain behavioral rules and operate in a given environment. It allows the user to simulate complex systems by varying user-defined parameters to study emergent, unpredicted behavior. The ABM incorporates the road network and electric utility grid for the state, is validated using actual storm event recoveries and utilizes the Dijkstra routing algorithm to determine the best path for repair crews to travel between outages. The ABM has benefits for both researchers and utility managers. It can simulate complex system dynamics, rank variable importance, find tipping points that could significantly reduce restoration time or costs and test a broad range of scenarios. It is a modular, scalable and adaptable technique that can simulate scenarios in silico to inform emergency managers before and during storm events to optimize restoration strategies and better manage expectations of when power will be restored. Results indicate that total restoration time is strongly dependent on the number of crews. However, there is a threshold whereby more crews will not decrease the restoration time, which depends on the total number of outages. The addition of outside crews is more beneficial for storms with a higher number of outages. The time to restoration increases linearly with increasing repair time, while the travel speed has little overall effect on total restoration time. Crews traveling to the nearest outage reduces the total restoration time, while crews going to the outage with most customers affected increases the overall restoration time but more quickly decreases the customers remaining without power. This model can give utility company managers the ability to optimize their restoration strategies before or during a storm event to reduce restoration times and costs.

Relevance of Clean Coal Technology for India’s Energy Security: A Policy Perspective

NASA Astrophysics Data System (ADS)

Garg, Amit; Tiwari, Vineet; Vishwanathan, Saritha

2017-07-01

Climate change mitigation regimes are expected to impose constraints on the future use of fossil fuels in order to reduce greenhouse gas (GHG) emissions. In 2015, 41% of total final energy consumption and 64% of power generation in India came from coal. Although almost a sixth of the total coal based thermal power generation is now super critical pulverized coal technology, the average CO2 emissions from the Indian power sector are 0.82 kg-CO2/kWh, mainly driven by coal. India has large domestic coal reserves which give it adequate energy security. There is a need to find options that allow the continued use of coal while considering the need for GHG mitigation. This paper explores options of linking GHG emission mitigation and energy security from 2000 to 2050 using the AIM/Enduse model under Business-as-Usual scenario. Our simulation analysis suggests that advanced clean coal technologies options could provide promising solutions for reducing CO2 emissions by improving energy efficiencies. This paper concludes that integrating climate change security and energy security for India is possible with a large scale deployment of advanced coal combustion technologies in Indian energy systems along with other measures.

Screening of Bioactive Compounds of Medicinal Mushrooms Collected on Tunisian Territory.

PubMed

Khadhri, Ayda; Aouadhi, Chedia; Aschi-Smiti, Samira

2017-01-01

This study is, to our knowledge, the first to investigate the pharmacological importance of wild Tunisian mushrooms. Ethanolic extracts of 5 Tunisian mushrooms-Phellinus torulosus, Fomes fomentarius, Trametes versicolor, Pisolithus albus, and Fomitopsis pinicola-were collected from the Kroumirie Region (North Tunisia). The dry basidomes of mushrooms were extracted using ethanol and evaluated for total polyphenol, flavonoid, flavonol, tannin, proanthocyanidin, and anthocyanin content. In addition, their antioxidant activities were determined using 3 assays (testing 2,2-diphenyl-1-picrylhydrazyl [DPPH] radical scavenging, the reducing power of iron, and the iron-chelating power). Their antimicrobial activities were assessed against 8 bacterial species. The results revealed the presence of significant differences between the secondary metabolites and biological activities of the different tested extracts. In addition, significant correlations were observed between antioxidant activities and phenolic contents. Crude ethanol extracts prepared from basidomes of F. fomentarius and Ph. torulosus have higher total phenolic content and antioxidant activity per the DPPH and metal-chelating activity assays. The reducing power assay showed that the ethanolic extract of F. pinicola had the highest activity. Ethanolic extracts of the 5 mushrooms have antibacterial activity against the evaluated strains.

Air pollution may alter efforts to mitigate climate change

NASA Astrophysics Data System (ADS)

Yassaa, Noureddine

2016-02-01

Renewable energy, considered in the past as a mitigation option to climate change by reducing carbon emission, is now becoming a source of energy security and competing fossil fuels in many areas of the world. According to recent reports (e.g., IEA, IRENA, REN21), renewable energy has reached in 2014 a historical record of power generation capacity. With 1712 GW installed capacity in 2014, renewable energy represents 27.7% of the world's power generating capacity. Solar photovoltaic (PV) energy, conversion of solar light to electricity through solar panels, has increased to reach 177 GW mostly due to the political engagement for the deployment of renewable through targeted programs and the decrease of PV panels prize in the market (roughly 80% decrease since 2008 according to IRENA's report). Concentrated Solar Power (CSP), reaching a total capacity of 4.4 GW in 2014 (REN21 Report), is also demonstrating a clear growth and progresses have been made with regards to the efficiency, the storage capacity and the cost. In order to reduce the energy consumption and carbon emissions, water solar heaters are being installed in the rooftop of households and a total capacity of 406 GW thermal was recorded in 2014 (REN21 Report).

A sensor-less LED dimming system based on daylight harvesting with BIPV systems.

PubMed

Yoo, Seunghwan; Kim, Jonghun; Jang, Cheol-Yong; Jeong, Hakgeun

2014-01-13

Artificial lighting in office buildings typically requires 30% of the total energy consumption of the building, providing a substantial opportunity for energy savings. To reduce the energy consumed by indoor lighting, we propose a sensor-less light-emitting diode (LED) dimming system using daylight harvesting. In this study, we used light simulation software to quantify and visualize daylight, and analyzed the correlation between photovoltaic (PV) power generation and indoor illumination in an office with an integrated PV system. In addition, we calculated the distribution of daylight illumination into the office and dimming ratios for the individual control of LED lights. Also, we were able directly to use the electric power generated by PV system. As a result, power consumption for electric lighting was reduced by 40 - 70% depending on the season and the weather conditions. Thus, the dimming system proposed in this study can be used to control electric lighting to reduce energy use cost-effectively and simply.

The generation of pollution-free electrical power from solar energy.

NASA Technical Reports Server (NTRS)

Cherry, W. R.

1971-01-01

Projections of the U.S. electrical power demands over the next 30 years indicate that the U.S. could be in grave danger from power shortages, undesirable effluence, and thermal pollution. An appraisal of nonconventional methods of producing electrical power is conducted, giving particular attention to the conversion of solar energy into commercial quantities of electrical power by solar cells. It is found that 1% of the land area of the 48 states could provide the total electrical power requirements of the U.S. in the year 1990. The ultimate method of generating vast quantities of electrical power would be from a series of synchronous satellites which beam microwave power back to earth to be used wherever needed. Present high manufacturing costs of solar cells could be substantially reduced by using massive automated techniques employing abundant low cost materials.

Minimal RED cell pairs markedly improve electrode kinetics and power production in microbial reverse electrodialysis cells.

PubMed

Cusick, Roland D; Hatzell, Marta; Zhang, Fang; Logan, Bruce E

2013-12-17

Power production from microbial reverse electrodialysis cell (MRC) electrodes is substantially improved compared to microbial fuel cells (MFCs) by using ammonium bicarbonate (AmB) solutions in multiple RED cell pair stacks and the cathode chamber. Reducing the number of RED membranes pairs while maintaining enhanced electrode performance could help to reduce capital costs. We show here that using only a single RED cell pair (CP), created by operating the cathode in concentrated AmB, dramatically increased power production normalized to cathode area from both acetate (Acetate: from 0.9 to 3.1 W/m(2)-cat) and wastewater (WW: 0.3 to 1.7 W/m(2)), by reducing solution and charge transfer resistances at the cathode. A second RED cell pair increased RED stack potential and reduced anode charge transfer resistance, further increasing power production (Acetate: 4.2 W/m(2); WW: 1.9 W/m(2)). By maintaining near optimal electrode power production with fewer membranes, power densities normalized to total membrane area for the 1-CP (Acetate: 3.1 W/m(2)-mem; WW: 1.7 W/m(2)) and 2-CP (Acetate: 1.3 W/m(2)-mem; WW: 0.6 W/m(2)) reactors were much higher than previous MRCs (0.3-0.5 W/m(2)-mem with acetate). While operating at peak power, the rate of wastewater COD removal, normalized to reactor volume, was 30-50 times higher in 1-CP and 2-CP MRCs than that in a single chamber MFC. These findings show that even a single cell pair AmB RED stack can significantly enhance electrical power production and wastewater treatment.

Autonomous exoskeleton reduces metabolic cost of walking.

PubMed

Mooney, Luke M; Rouse, Elliott J; Herr, Hugh M

2014-01-01

We developed an autonomous powered leg exoskeleton capable of providing large amounts of positive mechanical power to the wearer during powered plantarflexion phase of walking. The autonomous exoskeleton consisted of a winch actuator fasted to the shin which pulled on fiberglass struts attached to a boot. The fiberglass struts formed a rigid extension of the foot when the proximal end of the strut was pulled in forward by the winch actuator. This lightweight, geometric transmission allowed the electric winch actuator to efficiently produce biological levels of power at the ankle joint. The exoskeleton was powered and controlled by lithium polymer batteries and motor controller worn around the waist. Preliminary testing on two subjects walking at 1.4 m/s resulted in the exoskeleton reducing the metabolic cost of walking by 6-11% as compared to not wearing the device. The exoskeleton provided a peak mechanical power of over 180 W at each ankle (mean standard ± deviation) and an average positive mechanical power of 27 ± 1 W total to both ankles, while electrically using 75-89 W of electricity. The batteries (800 g) used in this experiment are estimated to be capable of providing this level of assistance for up to 7 km of walking.

Greening the Grid: Pathways to Integrate 175 Gigawatts of Renewable Energy into India’s Electric Grid, Vol. 1. National Study

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

Palchak, David; Cochran, Jaquelin; Deshmukh, Ranjit

The use of renewable energy (RE) sources, primarily wind and solar generation, is poised to grow significantly within the Indian power system. The Government of India has established a target of 175 gigawatts (GW) of installed RE capacity by 2022, including 60 GW of wind and 100 GW of solar, up from 29 GW wind and 9 GW solar at the beginning of 2017. Using advanced weather and power system modeling made for this project, the study team is able to explore operational impacts of meeting India’s RE targets and identify actions that may be favorable for integration. Our primarymore » tool is a detailed production cost model, which simulates optimal scheduling and dispatch of available generation in a future year (2022) by minimizing total production costs subject to physical, operational, and market constraints. Our team comprises a core group from the Power System Operation Corporation, Ltd. (POSOCO), which is the national grid operator (with representation from the National, Southern, and Western Regional Load Dispatch Centers) under Ministry of Power, National Renewable Energy Laboratory (NREL), and Lawrence Berkeley National Laboratory (Berkeley Lab), and a broader modeling team that includes Central Electricity Authority (CEA), POWERGRID (the central transmission utility, CTU), and State Load Dispatch Centers in Maharashtra, Gujarat, Tamil Nadu, Karnataka, Rajasthan, and Andhra Pradesh. Our model includes high-resolution wind and solar data (forecasts and actuals), unique properties for each generator, CEA/CTU’s anticipated buildout of the power system, and enforced state-to-state transmission flows. Assuming the fulfillment of current efforts to provide better access to the physical flexibility of the power system, we find that power system balancing with 100 GW of solar and 60 GW of wind is achievable at 15-minute operational timescales with minimal RE curtailment. This RE capacity meets 22% of total projected 2022 electricity consumption in India with annual RE curtailment of 1.4%, in line with experiences in other countries with significant RE penetrations (Bird et al. 2016). Changes to operational practice can further reduce the cost of operating the power system and reduce RE curtailment. Coordinating scheduling and dispatch over a broader area is the largest driver to reduce costs, saving INR 6300 crore (USD 980 million) annually when optimized regionally. Lowering minimum operating levels of coal plants (from 70% to 40%) is the biggest driver to reduce RE curtailment—from 3.5% down to 0.76%. In fact, this operating property is more influential than faster thermal generation ramp rates in lowering the projected levels of curtailment. While this study does not answer every question relevant to planning for India’s 2022 RE targets, it is an important step toward analyzing operational challenges and cost saving opportunities using state-of-the-art power system planning tools. Further analysis can build upon this basis to explore optimal renewable resource and intrastate transmission siting, system stability during contingencies, and the influence of total power system investment costs on customer tariffs.« less

Greening the Grid: Pathways to Integrate 175 Gigawatts of Renewable Energy into India's Electric Grid, Vol. I -- National Study

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

Palchak, David; Cochran, Jaquelin; Ehlen, Ali

The use of renewable energy (RE) sources, primarily wind and solar generation, is poised to grow significantly within the Indian power system. The Government of India has established a target of 175 gigawatts (GW) of installed RE capacity by 2022, including 60 GW of wind and 100 GW of solar, up from 29 GW wind and 9 GW solar at the beginning of 2017. Thanks to advanced weather and power system modeling made for this project, the study team is able to explore operational impacts of meeting India's RE targets and identify actions that may be favorable for integration. Ourmore » primary tool is a detailed production cost model, which simulates optimal scheduling and dispatch of available generation in a future year (2022) by minimizing total production costs subject to physical, operational, and market constraints. Our team comprises a core group from the Power System Operation Corporation, Ltd. (POSOCO), which is the national grid operator (with representation from the National, Southern, and Western Regional Load Dispatch Centers) under Ministry of Power, National Renewable Energy Laboratory (NREL), and Lawrence Berkeley National Laboratory (LBNL), and a broader modeling team that includes Central Electricity Authority (CEA), POWERGRID (the central transmission utility, CTU), and State Load Dispatch Centers in Maharashtra, Gujarat, Tamil Nadu, Karnataka, Rajasthan, and Andhra Pradesh. Our model includes high-resolution wind and solar data (forecasts and actuals), unique properties for each generator, CEA/CTU's anticipated buildout of the power system, and enforced state-to-state transmission flows. Assuming the fulfillment of current efforts to provide better access to the physical flexibility of the power system, we find that power system balancing with 100 GW of solar and 60 GW of wind is achievable at 15-minute operational timescales with minimal RE curtailment. This RE capacity meets 22% of total projected 2022 electricity consumption in India with annual RE curtailment of 1.4%, in line with experiences in other countries with significant RE penetrations (Bird et al. 2016). Changes to operational practice can further reduce the cost of operating the power system and reduce RE curtailment. Coordinating scheduling and dispatch over a broader area is the largest driver to reduce costs, saving INR 6300 crore (USD $920 million) annually when optimized regionally. Lowering minimum operating levels of coal plants (from 70% to 40%) is the biggest driver to reduce RE curtailment - from 3.5% down to 0.76%. In fact, this operating property is more influential than faster thermal generation ramp rates in lowering the projected levels of curtailment. While this study does not answer every question relevant to planning for India's 2022 RE targets, it is an important step toward analyzing operational challenges and cost saving opportunities using state-of-the-art power system planning tools. Further analysis can build upon this basis to explore optimal renewable resource and intrastate transmission siting, system stability during contingencies, and the influence of total power system investment costs on customer tariffs.« less

New Approach to Optimize the Apfs Placement Based on Instantaneous Reactive Power Theory by Genetic Algorithm

NASA Astrophysics Data System (ADS)

Hashemi-Dezaki, Hamed; Mohammadalizadeh-Shabestary, Masoud; Askarian-Abyaneh, Hossein; Rezaei-Jegarluei, Mohammad

2014-01-01

In electrical distribution systems, a great amount of power are wasting across the lines, also nowadays power factors, voltage profiles and total harmonic distortions (THDs) of most loads are not as would be desired. So these important parameters of a system play highly important role in wasting money and energy, and besides both consumers and sources are suffering from a high rate of distortions and even instabilities. Active power filters (APFs) are innovative ideas for solving of this adversity which have recently used instantaneous reactive power theory. In this paper, a novel method is proposed to optimize the allocation of APFs. The introduced method is based on the instantaneous reactive power theory in vectorial representation. By use of this representation, it is possible to asses different compensation strategies. Also, APFs proper placement in the system plays a crucial role in either reducing the losses costs and power quality improvement. To optimize the APFs placement, a new objective function has been defined on the basis of five terms: total losses, power factor, voltage profile, THD and cost. Genetic algorithm has been used to solve the optimization problem. The results of applying this method to a distribution network illustrate the method advantages.

Quality Control of Gamma Irradiated Dwarf Mallow (Malva neglecta Wallr.) Based on Color, Organic Acids, Total Phenolics and Antioxidant Parameters.

PubMed

Pinela, José; Barros, Lillian; Antonio, Amilcar L; Carvalho, Ana Maria; Oliveira, M Beatriz P P; Ferreira, Isabel C F R

2016-04-08

This study addresses the effects of gamma irradiation (1, 5 and 8 kGy) on color, organic acids, total phenolics, total flavonoids, and antioxidant activity of dwarf mallow (Malva neglecta Wallr.). Organic acids were analyzed by ultra fast liquid chromatography (UFLC) coupled to a photodiode array (PDA) detector. Total phenolics and flavonoids were measured by the Folin-Ciocalteu and aluminium chloride colorimetric methods, respectively. The antioxidant activity was evaluated based on the DPPH(•) scavenging activity, reducing power, β-carotene bleaching inhibition and thiobarbituric acid reactive substances (TBARS) formation inhibition. Analyses were performed in the non-irradiated and irradiated plant material, as well as in decoctions obtained from the same samples. The total amounts of organic acids and phenolics recorded in decocted extracts were always higher than those found in the plant material or hydromethanolic extracts, respectively. The DPPH(•) scavenging activity and reducing power were also higher in decocted extracts. The assayed irradiation doses affected differently the organic acids profile. The levels of total phenolics and flavonoids were lower in the hydromethanolic extracts prepared from samples irradiated at 1 kGy (dose that induced color changes) and in decocted extracts prepared from those irradiated at 8 kGy. The last samples also showed a lower antioxidant activity. In turn, irradiation at 5 kGy favored the amounts of total phenolics and flavonoids. Overall, this study contributes to the understanding of the effects of irradiation in indicators of dwarf mallow quality, and highlighted the decoctions for its antioxidant properties.

Phenolic content and antioxidant activity of Pereskia grandifolia Haw. (Cactaceae) extracts

PubMed Central

Sim, K. S.; Nurestri, A. M. Sri; Norhanom, A. W.

2010-01-01

The leaves of Pereskia grandifolia Haw. (Cactaceae), commonly known as “Jarum Tujuh Bilah” in Malaysia, have been traditionally used as natural remedy in folk medicine by the locals. In the present study, the antioxidant potential of P. grandifolia crude methanol and its fractionated extracts (hexane, ethyl acetate and water) have been investigated, employing three different established testing systems, such as scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, reducing power assay and β-carotene method. The total phenolic content of the P. grandifolia extracts was also assessed by the Folin-Ciocalteau’s method. The ethyl acetate extract showed significantly the highest total phenolic content, DPPH scavenging ability and antioxidant activity in β-carotene bleaching assay while the hexane extract possessed significantly strongest reducing power. The data obtained in these testing systems clearly establish the antioxidant potency of P. grandifolia. As such, this is the first report on the antioxidant activities of P. grandifolia. PMID:20931088

A study of extraction process and in vitro antioxidant activity of total phenols from Rhizoma Imperatae.

PubMed

Zhou, Xian-rong; Wang, Jian-hua; Jiang, Bo; Shang, Jin; Zhao, Chang-qiong

2013-01-01

The study investigated the extraction method of Rhizoma Imperatae and its antioxidant activity, and provided a basis for its rational development. The extraction method of Rhizoma Imperatae was determined using orthogonal design test and by total phenol content, its hydroxyl radical scavenging ability was measured by Fenton reaction, and potassium ferricyanide reduction method was used to determine its reducing power. The results showed that the optimum extraction process of Rhizoma Imperatae was a 50-fold volume of water, 30 °C, three times of extraction with 2 h each. Its IC50 for scavenging of hydroxyl radicals was 0.0948 mg/mL, while IC50 of ascorbic acid was 0.1096 mg/mL; in the ferricyanide considerable reduction method, the extract exhibited reducing power comparable to that of the ascorbic acid. The study concluded that Rhizoma Imperatae extract contains relatively large amount of polyphenols, and has a good anti-oxidation ability.

Charging power optimization for nonlinear vibration energy harvesting systems subjected to arbitrary, persistent base excitations

NASA Astrophysics Data System (ADS)

Dai, Quanqi; Harne, Ryan L.

2018-01-01

The vibrations of mechanical systems and structures are often a combination of periodic and random motions. Emerging interest to exploit nonlinearities in vibration energy harvesting systems for charging microelectronics may be challenged by such reality due to the potential to transition between favorable and unfavorable dynamic regimes for DC power delivery. Therefore, a need exists to devise an optimization method whereby charging power from nonlinear energy harvesters remains maximized when excitation conditions are neither purely harmonic nor purely random, which have been the attention of past research. This study meets the need by building from an analytical approach that characterizes the dynamic response of nonlinear energy harvesting platforms subjected to combined harmonic and stochastic base accelerations. Here, analytical expressions are formulated and validated to optimize charging power while the influences of the relative proportions of excitation types are concurrently assessed. It is found that about a 2 times deviation in optimal resistive loads can reduce the charging power by 20% when the system is more prominently driven by harmonic base accelerations, whereas a greater proportion of stochastic excitation results in a 11% reduction in power for the same resistance deviation. In addition, the results reveal that when the frequency of a predominantly harmonic excitation deviates by 50% from optimal conditions the charging power reduces by 70%, whereas the same frequency deviation for a more stochastically dominated excitation reduce total DC power by only 20%. These results underscore the need for maximizing direct current power delivery for nonlinear energy harvesting systems in practical operating environments.

Polyphenolic content, in vitro antioxidant activity and chemical composition of extract from Nephelium lappaceum L. (Mexican rambutan) husk.

PubMed

Hernández, Cristian; Ascacio-Valdés, Juan; De la Garza, Heliodoro; Wong-Paz, Jorge; Aguilar, Cristóbal Noé; Martínez-Ávila, Guillermo Cristian; Castro-López, Cecilia; Aguilera-Carbó, Antonio

2017-12-01

To determinate the recovery of total polyphenolic compounds content, in vitro antioxidant activity and HPLC/ESI/MS characterization of extract from Nephelium lappaceum L. (Mexican rambutan). The rambutan husk extract was obtained by aqueous extraction and a polyphenolic fraction was recovered using Amberlite XAD-16. The total polyphenolic compounds content was determined by the Folin Ciocalteu and butanol-HCI methods. In vitro antioxidant activity was performed using ABTS and ferric reducing antioxidant power methods. Mexican rambutan husk showed a total polyphenolic content of 582 mg/g and an evident antioxidant activity by ABTS and ferric reducing antioxidant power analysis. The HPLC/ESI/MS assay allowed the identification of 13 compounds, most of which belong to ellagitannins. Geraniin, corilagin and ellagic acid were present in the sample; the mineral composition was also evaluated. Rambutan husk cultivated in Mexico is a promising source for the recovery of added value bioactive compounds with antioxidant activity, which have potential applications as bioactive antioxidant agents for the treatment of diseases. Copyright © 2017 Hainan Medical University. Production and hosting by Elsevier B.V. All rights reserved.

In vitro evaluation of free radical scavenging activity of Codariocalyx motorius root extract.

PubMed

Chidambaram, Uma; Pachamuthu, Vanitha; Natarajan, Suganya; Elango, Bhakkiyalakshmi; Suriyanarayanan; Ramkumar, Kunga Mohan

2013-03-01

To determine the phenolic content in Codariocalyx motorius root extract and to evaluate its antioxidant properties using various in vitro assay systems. The antioxidant activity was evaluated based on scavenging of 1,1-diphenyl-2-picrylhydrazyl, hydroxyl radicals, superoxide anions, nitric oxide, hydrogen peroxide, peroxynitrite, reducing power and by inhibition of lipid peroxidation which was estimated in terms of thiobarbituric acid reactive substances. The root extract of the Codariocalyx motorius (C. motorius) exhibited potent total antioxidant activity that increased with increasing amount of extract concentration, which was compared with standard drug such as quercetin, butylated hydroxytoluene, tocopherol at different concentrations. The different concentrations of the extracts showed inhibition on lipid peroxidation. In addition, the extracts had effective reducing power, free radical scavenging, super oxide anion scavenging, nitric oxide scavenging, lipid peroxidation, and total phenolic content depending on concentration. High correlation between total phenolic contents and scavenging potential of different reactive oxygen species (r(2)=0.831-0.978) indicated the polyphenols as the main antioxidants. Codariocalyx motorius (C. motorius) root possess the highly active antioxidant substance which can be used for the treatment of oxidative stress-related diseases. Copyright © 2013 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

10 GHz dual loop opto-electronic oscillator without RF-amplifiers

NASA Astrophysics Data System (ADS)

Zhou, Weimin; Okusaga, Olukayode; Nelson, Craig; Howe, David; Carter, Gary

2008-02-01

We report the first demonstration of a 10 GHz dual-fiber-loop Opto-Electronic Oscillator (OEO) without RF-amplifiers. Using a recently developed highly efficient RF-Photonic link with RF-to-RF gain facilitated by a high power laser, highly efficient optical modulator and high power phototectectors, we have built an amplifier-less OEO that eliminates the phase noise produced by the electronic amplifier. The dual-loop approach can provide additional gain and reduce unwanted multi-mode spurs. However, we have observed RF phase noise produced by the high power laser include relative intensity noise (RIN) and noise related to the laser's electronic control system. In addition, stimulated Brillouin scattering limits the fiber loop's length to ~2km at the 40mW laser power needed to provide the RF gain which limits the system's quality factor, Q. We have investigated several different methods for solving these problems. One promising technique is the use of a multi-longitudinal-mode laser to carry the RF signal, maintaining the total optical power but reducing the optical power of each mode to eliminate the Brillouin scattering in a longer fiber thereby reducing the phase noise of the RF signal produced by the OEO. This work shows that improvement in photonic components increases the potential for more RF system applications such as an OEO's with higher performance and new capabilities.

Samarium Diiodide-Mediated Reactions in Total Synthesis

PubMed Central

Nicolaou, K. C.; Ellery, Shelby P.; Chen, Jason S.

2009-01-01

Introduced by Henri Kagan more than three decades ago, samarium diiodide (SmI2) has found increasing applications in chemical synthesis. This single-electron reducing agent has been particularly useful in C–C bond formations, including those found in total synthesis endeavors. This Review highlights selected applications of SmI2 in total synthesis, with special emphasis on novel transformations and mechanistic considerations. The examples discussed are both illustrative of the power of this reagent in complex molecule construction and inspirational for the design of synthetic strategies toward such targets, both natural and designed. PMID:19714695

Human life support during interplanetary travel and domicile. III - Mars expedition system trade study

NASA Technical Reports Server (NTRS)

Seshan, P. K.; Ferrall, Joseph F.; Rohatgi, Naresh K.

1991-01-01

Several alternative configurations of life-support systems (LSSs) for a Mars missions are compared analytically on a quantitative basis in terms of weight, volume, and power. A baseline technology set is utilized for the illustrations of systems including totally open loop, carbon dioxide removal only, partially closed loop, and totally closed loop. The analytical model takes advantage of a modular, top-down hierarchical breakdown of LSS subsystems into functional elements that represent individual processing technologies. The open-loop systems are not competitive in terms of weight for both long-duration orbiters and short-duration lander vehicles, and power demands are lowest with the open loop and highest with the closed loop. The closed-loop system can reduce vehicle weight by over 70,000 lbs and thereby overcome the power penalty of 1600 W; the closed-loop variety is championed as the preferred system for a Mars expedition.

Comparative life cycle assessment of biogas plant configurations for a demand oriented biogas supply for flexible power generation.

PubMed

Hahn, Henning; Hartmann, Kilian; Bühle, Lutz; Wachendorf, Michael

2015-03-01

The environmental performance of biogas plant configurations for a demand - oriented biogas supply for flexible power generation is comparatively assessed in this study. Those configurations indicate an increased energy demand to operate the operational enhancements compared to conventional biogas plants supplying biogas for baseload power generation. However, findings show that in contrast to an alternative supply of power generators with natural gas, biogas supplied on demand by adapted biogas plant configurations saves greenhouse gas emissions by 54-65 g CO(2-eq) MJ(-1) and primary energy by about 1.17 MJ MJ(-1). In this regard, configurations with flexible biogas production profit from reduced biogas storage requirements and achieve higher savings compared to configurations with continuous biogas production. Using thicker biogas storage sheeting material reduces the methane permeability of up to 6m(3) d(-1) which equals a reduction of 8% of the configuration's total methane emissions. Copyright © 2014 Elsevier Ltd. All rights reserved.

LDMOS Channel Thermometer Based on a Thermal Resistance Sensor for Balancing Temperature in Monolithic Power ICs.

PubMed

Lin, Tingyou; Ho, Yingchieh; Su, Chauchin

2017-06-15

This paper presents a method of thermal balancing for monolithic power integrated circuits (ICs). An on-chip temperature monitoring sensor that consists of a poly resistor strip in each of multiple parallel MOSFET banks is developed. A temperature-to-frequency converter (TFC) is proposed to quantize on-chip temperature. A pulse-width-modulation (PWM) methodology is developed to balance the channel temperature based on the quantization. The modulated PWM pulses control the hottest of metal-oxide-semiconductor field-effect transistor (MOSFET) bank to reduce its power dissipation and heat generation. A test chip with eight parallel MOSFET banks is fabricated in TSMC 0.25 μm HV BCD processes, and total area is 900 × 914 μm². The maximal temperature variation among the eight banks can reduce to 2.8 °C by the proposed thermal balancing system from 9.5 °C with 1.5 W dissipation. As a result, our proposed system improves the lifetime of a power MOSFET by 20%.

LDMOS Channel Thermometer Based on a Thermal Resistance Sensor for Balancing Temperature in Monolithic Power ICs

PubMed Central

Lin, Tingyou; Ho, Yingchieh; Su, Chauchin

2017-01-01

This paper presents a method of thermal balancing for monolithic power integrated circuits (ICs). An on-chip temperature monitoring sensor that consists of a poly resistor strip in each of multiple parallel MOSFET banks is developed. A temperature-to-frequency converter (TFC) is proposed to quantize on-chip temperature. A pulse-width-modulation (PWM) methodology is developed to balance the channel temperature based on the quantization. The modulated PWM pulses control the hottest of metal-oxide-semiconductor field-effect transistor (MOSFET) bank to reduce its power dissipation and heat generation. A test chip with eight parallel MOSFET banks is fabricated in TSMC 0.25 μm HV BCD processes, and total area is 900 × 914 μm2. The maximal temperature variation among the eight banks can reduce to 2.8 °C by the proposed thermal balancing system from 9.5 °C with 1.5 W dissipation. As a result, our proposed system improves the lifetime of a power MOSFET by 20%. PMID:28617346

Antioxidant, analgesic and anti-inflammatory activities of the methanolic extract of Piper betle leaves

PubMed Central

Alam, Badrul; Akter, Fahima; Parvin, Nahida; Sharmin Pia, Rashna; Akter, Sharmin; Chowdhury, Jesmin; Sifath-E-Jahan, Kazi; Haque, Ekramul

2013-01-01

Objective: The present study was designed to evaluate the antioxidant, analgesic, and anti-inflammatory activities of the methanolic extract of Piper betle leaves (MPBL). Materials and Methods: MPBL was evaluated for anti-inflammatory activity using carrageenan-induced hind paw edema model. Analgesic activity of MPBL was evaluated by hot plate, writhing, and formalin tests. Total phenolic and flavonoids content, total antioxidant activity, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, peroxynitrate (ONOO) as well as inhibition of total ROS generation, and assessment of reducing power were used to evaluate antioxidant potential of MPBL. Results: The extract of MPBL, at the dose of 100 and 200 mg/kg, produced a significant (p<0.05) increase in pain threshold in hot plate method whereas significantly (p<0.05) reduced the writhing caused by acetic acid and the number of licks induced by formalin in a dose-dependent manner. The same ranges of doses of MPBL caused significant (p<0.05) inhibition of carrageenan-induced paw edema after 4 h in a dose-dependent manner. In DPPH, ONOO-, and total ROS scavenging method, MPBL showed good antioxidant potentiality with the IC50 value of 16.33±1.02, 25.16±0.61 , and 41.72±0.48 µg/ml, respectively with a significant (p<0.05) good reducing power. Conclusion: The findings of the study suggested that MPBL has strong analgesic, anti-inflammatory, and antioxidant effects, conforming the traditional use of this plant for inflammatory pain alleviation to its antioxidant potentiality. PMID:25050265

Desktop Virtualization in Action: Simplicity Is Power

ERIC Educational Resources Information Center

Fennell, Dustin

2010-01-01

Discover how your institution can better manage and increase access to instructional applications and desktops while providing a blended learning environment. Receive practical insight into how academic computing virtualization can be leveraged to enhance education at your institution while lowering Total Cost of Ownership (TCO) and reducing the…

Energy saving in data processing and communication systems.

PubMed

Iazeolla, Giuseppe; Pieroni, Alessandra

2014-01-01

The power management of ICT systems, that is, data processing (Dp) and telecommunication (Tlc) systems, is becoming a relevant problem in economical terms. Dp systems totalize millions of servers and associated subsystems (processors, monitors, storage devices, etc.) all over the world that need to be electrically powered. Dp systems are also used in the government of Tlc systems, which, besides requiring Dp electrical power, also require Tlc-specific power, both for mobile networks (with their cell-phone towers and associated subsystems: base stations, subscriber stations, switching nodes, etc.) and for wired networks (with their routers, gateways, switches, etc.). ICT research is thus expected to investigate into methods to reduce Dp- and Tlc-specific power consumption. However, saving power may turn into waste of performance, in other words, into waste of ICT quality of service (QoS). This paper investigates the Dp and Tlc power management policies that look at compromises between power saving and QoS.

Differential effects of power training versus functional task practice on compensation and restoration of arm function after stroke.

PubMed

Corti, Manuela; McGuirk, Theresa E; Wu, Samuel S; Patten, Carolynn

2012-09-01

Improved upper-extremity (UE) movement with stroke rehabilitation may involve restoration of more normal or development of compensatory movement patterns. The authors investigated the differential effects of functional task practice (FTP) and dynamic resistance training (POWER) on clinical function and reaching kinematics in an effort to distinguish between mechanisms of gains. A total of 14 hemiparetic individuals were randomly assigned to 10 weeks of either FTP or POWER and then crossed over to 10 weeks of the alternate treatment. Treatment order A was FTP followed by POWER, whereas treatment order B was POWER followed by FTP. Evaluation before and after each treatment block included a battery of clinical evaluations and kinematics of paretic UE functional reach to grasp. Both FTP and POWER improved movement accuracy, as revealed by a shift toward normal, including fewer submovements and reduced reach-path ratio. However, active range of motion revealed differential treatment effects. Shoulder flexion and elbow extension decreased with FTP and were associated with increased trunk displacement. In contrast, shoulder flexion and elbow extension excursion increased with POWER and were associated with significantly reduced trunk displacement. Treatment order B (POWER followed by FTP) revealed greater overall improvements. FTP increases compensatory movement patterns to improve UE function. POWER leads to more normal movement patterns. POWER prior to FTP may enhance the benefits of repetitive task practice.

The independent effects of speed and propulsive force on joint power generation in walking.

PubMed

Browne, Michael G; Franz, Jason R

2017-04-11

Walking speed is modulated using propulsive forces (F P ) during push-off and both preferred speed and F P decrease with aging. However, even prior to walking slower, reduced F P may be accompanied by potentially unfavorable changes in joint power generation. For example, compared to young adults, older adults exhibit a redistribution of mechanical power generation from the propulsive plantarflexor muscles to more proximal muscles acting across the knee and hip. Here, we used visual biofeedback based on real-time F P measurements to decouple and investigate the interaction between joint-level coordination, whole-body F P , and walking speed. 12 healthy young subjects walked on a dual-belt instrumented treadmill at a range of speeds (0.9-1.3m/s). We immediately calculated the average F P from each speed. Subjects then walked at 1.3m/s while completing a series of biofeedback trials with instructions to match their instantaneous F P to their averaged F P from slower speeds. Walking slower decreased F P and total positive joint work with little effect on relative joint-level contributions. Conversely, subjects walked at a constant speed with reduced F P , not by reducing total positive joint work, but by redistributing the mechanical demands of each step from the plantarflexor muscles during push-off to more proximal leg muscles during single support. Interestingly, these naturally emergent joint- and limb-level biomechanical changes, in the absence of neuromuscular constraints, resemble those due to aging. Our findings provide important reference data to understand the presumably complex interactions between joint power generation, whole-body F P , and walking speed in our aging population. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative assessment on in vitro antioxidant activities of ethanol extracts of Averrhoa bilimbi, Gymnema sylvestre and Capsicum frutescens

PubMed Central

Rahman, Md. Mominur; Habib, Md. Razibul; Hasan, Md. Anayet; Al Amin, Mohammad; Saha, Ayan; Mannan, Adnan

2014-01-01

Background: Averrhoa bilimbi, Gymnema sylvestre and Capsicum frutescens are medicinal plants commonly used as traditional medicine for the treatment of various diseases. The present study was designed to investigate the antioxidant activities of Ethanolic extract of A. bilimbi, G. sylvestre and C. frutescens. Materials and Methods: The antioxidant activity of the extracts were evaluated using total phenolic and flavonoid contents, ferric reducing power and the free radical scavenging activity against 1,1-diphenyl-2-picrylhydrazyl (DPPH). Results: Total phenolic and flavonoid contents were higher in G. sylvestre (53.63636 ± 0.454545 mg/g gallic acid equivalent) and C. frutescens (26.66667 ± 2.081666 mg/g quercetin equivalent) respectively. Reducing power of the crude ethanol extracts increased with the concentrations of the extracts and all the extracts showed moderate free radical scavenging activity against DPPH. The plant extract displayed moderate phenolic and flavonoid contents compared to gallic acid and quercetin equivalent respectively, whereas also exhibited significant scavenging of DPPH radical and reducing power compared with ascorbic acid as standard. Conclusion: Our study suggests that G. sylvestre has significant antioxidant activity. The antioxidant compound of this plant might be a therapeutic candidate against oxidative stress related diseases. Different sub-fraction of A. bilimbi and C. frutescens should be studied further to assess the effect. Further study is necessary for isolation and characterization of the active antioxidant agents for better treatment. PMID:24497740

Radiation-Tolerant DC-DC Converters

NASA Technical Reports Server (NTRS)

Skutt, Glenn; Sable, Dan; Leslie, Leonard; Graham, Shawn

2012-01-01

A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed. Development and compliance testing of standard hybrid converters suitable for space use were completed for missions with total dose radiation requirements of up to 30 kRad. This innovation provides the same overall performance as standard hybrid converters, but includes assurance of radiation- tolerant design through components and design compliance testing. This availability of design-certified radiation-tolerant converters can significantly reduce total cost and delivery time for power converters for space applications that fit the appropriate DSCC classification (30 kRad).

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%.

Changes in lower extremity movement and power absorption during forefoot striking and barefoot running.

PubMed

Williams, D S Blaise; Green, Douglas H; Wurzinger, Brian

2012-10-01

Both forefoot strike shod (FFS) and barefoot (BF) running styles result in different mechanics when compared to rearfoot strike (RFS) shod running. Additionally, running mechanics of FFS and BF running are similar to one another. Comparing the mechanical changes occurring in each of these patterns is necessary to understand potential benefits and risks of these running styles. The authors hypothesized that FFS and BF conditions would result in increased sagittal plane joint angles at initial contact and that FFS and BF conditions would demonstrate a shift in sagittal plane joint power from the knee to the ankle when compared to the RFS condition. Finally, total lower extremity power absorption will be least in BF and greatest in the RFS shod condition. The study included 10 male and 10 female RFS runners who completed 3-dimensional running analysis in 3 conditions: shod with RFS, shod with FFS, and BF. Variables were the angles of plantarflexion, knee flexion, and hip flexion at initial contact and peak sagittal plane joint power at the hip, knee, and ankle during stance phase. Running with a FFS pattern and BF resulted in significantly greater plantarflexion and significantly less negative knee power (absorption) when compared to shod RFS condition. FFS condition runners landed in the most plantarflexion and demonstrated the most peak ankle power absorption and lowest knee power absorption between the 3 conditions. BF and FFS conditions demonstrated decreased total lower extremity power absorption compared to the shod RFS condition but did not differ from one another. BF and FFS running result in reduced total lower extremity power, hip power and knee power and a shift of power absorption from the knee to the ankle. Alterations associated with BF running patterns are present in a FFS pattern when wearing shoes. Additionally, both patterns result in increased demand at the foot and ankle as compared to the knee.

CHANGES IN LOWER EXTREMITY MOVEMENT AND POWER ABSORPTION DURING FOREFOOT STRIKING AND BAREFOOT RUNNING

PubMed Central

Green, Douglas H.; Wurzinger, Brian

2012-01-01

Purpose/Background: Both forefoot strike shod (FFS) and barefoot (BF) running styles result in different mechanics when compared to rearfoot strike (RFS) shod running. Additionally, running mechanics of FFS and BF running are similar to one another. Comparing the mechanical changes occurring in each of these patterns is necessary to understand potential benefits and risks of these running styles. The authors hypothesized that FFS and BF conditions would result in increased sagittal plane joint angles at initial contact and that FFS and BF conditions would demonstrate a shift in sagittal plane joint power from the knee to the ankle when compared to the RFS condition. Finally, total lower extremity power absorption will be least in BF and greatest in the RFS shod condition. Methods: The study included 10 male and 10 female RFS runners who completed 3‐dimensional running analysis in 3 conditions: shod with RFS, shod with FFS, and BF. Variables were the angles of plantarflexion, knee flexion, and hip flexion at initial contact and peak sagittal plane joint power at the hip, knee, and ankle during stance phase. Results: Running with a FFS pattern and BF resulted in significantly greater plantarflexion and significantly less negative knee power (absorption) when compared to shod RFS condition. FFS condition runners landed in the most plantarflexion and demonstrated the most peak ankle power absorption and lowest knee power absorption between the 3 conditions. BF and FFS conditions demonstrated decreased total lower extremity power absorption compared to the shod RFS condition but did not differ from one another. Conclusions: BF and FFS running result in reduced total lower extremity power, hip power and knee power and a shift of power absorption from the knee to the ankle. Clinical Relevance: Alterations associated with BF running patterns are present in a FFS pattern when wearing shoes. Additionally, both patterns result in increased demand at the foot and ankle as compared to the knee. PMID:23091785

POWER PLANT EVALUATION OF THE EFFECT OF SCR TECHNOLOGY ON MERCURY

EPA Science Inventory

The paper presents results of research on the impact that selective catalytic reduction (SCR) systems have on speciation and total emissions of mercury. Although SCR systems are designed to reduce nitrogen oxides (NOx), they may oxidize elemental mercury (Hg0) to Hg2+, which is m...

Antioxidant Contents and Antioxidant Activities of White and Colored Potatoes (Solanum tuberosum L.).

PubMed

Lee, Sang Hoon; Oh, Seung Hee; Hwang, In Guk; Kim, Hyun Young; Woo, Koan Sik; Woo, Shun Hee; Kim, Hong Sig; Lee, Junsoo; Jeong, Heon Sang

2016-06-01

This study was performed to evaluate and compare the antioxidant substance content and antioxidant activities of white (Superior) and colored (Hongyoung, Jayoung, Jasim, Seohong, and Jaseo) potatoes. The potatoes were extracted with 80% ethanol and were evaluated for the total polyphenol, flavonoid, and anthocyanin contents and for 1,1-diphenyl- 2-picrylhydrazyl (DPPH)/2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging activity, reducing power, and ferrous metal ion chelating effect. The total polyphenol, flavonoid, and anthocyanin contents of Hongyoung and Jayoung were higher than white and other colored potatoes. All colored potato extracts, except for Jaseo and Seohong, showed higher ABTS radical scavenging activities than the general white potato extract. Hongyoung and Jayoung had the highest ABTS and DPPH radical scavenging activities. Optical density values for the reducing power of Jayoung and Jaseo at concentration of 2 mg/mL were 0.148 and 0.090, respectively. All colored potato extracts had lower ferrous metal ion chelating effect than the white potato. A significant (P<0.05) positive correlation was observed between total polyphenol content and total flavonoid content (r=0.919), anthocyanin content (r=0.992), and ABTS radical scavenging activity (r=0.897). Based on these results, this research may be useful in developing the Hongyoung and Jayoung cultivars with high antioxidant activities.

Bio-screening of a few green seaweeds from India for their cytotoxic and antioxidant potential.

PubMed

Vinayak, Rashmi C; Sudha, Sabu Appukuttan; Chatterji, Anil

2011-10-01

It has been evidenced in several epidemiological studies that seaweeds when consumed as diet protect against several chronic oxidative stress-related diseases. Seaweeds, raw, cooked, or dried, are used as food in many cultures, although not very popularly in India. Globally, several studies have indicated that seaweeds are a rich source of phenolic compounds and have antioxidant properties. In the present study, we screened methanolic extracts (MEs) of five species of green seaweeds commonly found in India for their cytotoxic activity by brine shrimp lethality assay and antioxidant properties using various in vitro assays, including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, reducing power and metal ion chelating assays. A markedly variable, dose-dependent activity was observed in all the seaweed extracts relative to their total phenolic content. Statistical analysis indicated a significantly strong correlation between the DPPH radical scavenging activity and total phenolic content (R(2) = 0.88, P < 0.05) as well as reducing power and total phenolic content (R(2) = 0.99, P < 0.01) of the dry MEs. Also, a very poor correlation between total phenolic content and metal chelating activity (R(2) = 0.13, P > 0.05) was noted. None of the seaweed extracts were potently cytotoxic. The underlying results endorse seaweeds as a rich, novel source of antioxidant compounds needing systemic exploration. Copyright © 2011 Society of Chemical Industry.

Application of Superconducting Power Cables to DC Electric Railway Systems

NASA Astrophysics Data System (ADS)

Ohsaki, Hiroyuki; Lv, Zhen; Sekino, Masaki; Tomita, Masaru

For novel design and efficient operation of next-generation DC electric railway systems, especially for their substantial energy saving, we have studied the feasibility of applying superconducting power cables to them. In this paper it is assumed that a superconducting power cable is applied to connect substations supplying electric power to trains. An analysis model line was described by an electric circuit, which was analyzed with MATLAB-Simulink. From the calculated voltages and currents of the circuit, the regenerative brake and the energy losses were estimated. In addition, assuming the heat loads of superconducting power cables and the cryogenic efficiency, the energy saving of the total system was evaluated. The results show that the introduction of superconducting power cables could achieve the improved use of regenerative brake, the loss reduction, the decreased number of substations, the reduced maintenance, etc.

Optimal power flow with optimal placement TCSC device on 500 kV Java-Bali electrical power system using genetic Algorithm-Taguchi method

NASA Astrophysics Data System (ADS)

Apribowo, Chico Hermanu Brillianto; Ibrahim, Muhammad Hamka; Wicaksono, F. X. Rian

2018-02-01

The growing burden of the load and the complexity of the power system has had an impact on the need for optimization of power system operation. Optimal power flow (OPF) with optimal location placement and rating of thyristor controlled series capacitor (TCSC) is an effective solution used to determine the economic cost of operating the plant and regulate the power flow in the power system. The purpose of this study is to minimize the total cost of generation by placing the location and the optimal rating of TCSC using genetic algorithm-design of experiment techniques (GA-DOE). Simulation on Java-Bali system 500 kV with the amount of TCSC used by 5 compensator, the proposed method can reduce the generation cost by 0.89% compared to OPF without using TCSC.

Antioxidant activities of methanol extract of Sambucus ebulus L. flower.

PubMed

Ebrahimzadeh, M A; Nabavi, S F; Nabavi, S M

2009-03-01

In this study antioxidant activity of methanol extract of Sambucus ebulus L. flower was investigated employing various in vitro assay systems, i.e., DPPH and nitric oxide radical scavenging, hydrogen peroxide scavenging, reducing power, iron ion chelating power and linoleic acid. IC50 for DPPH radical-scavenging activity was 228 +/- 12 microg mL(-1). The extract showed very high activity in the reducing power assay that was comparable with positive control, vitamin C. The extract showed good nitric oxide-scavenging activity (IC50 = 309 +/- 14 microg mL(-1). It was found that antioxidant activity was dose dependent i.e., activity was increased with the increase of their concentrations. The extract showed very weak activity in iron ion chelating (IC50 = 1.3 +/- 0.07 mg mL(-1)). It is showed very good activity in scavenging of hydrogen'peroxide. IC50 for scavenging of extract was 59.5 +/- 3.3 mcirog mL(-1). The extracts exhibited no activity in linoleic acid model. The total phenolic content of flower was 56.3 +/- 2.81 mg gallic acid equivalent g(-1) of extract powder and total flavonoid content was 14.5 +/- 0.72 mg quercetin equivalent g(-1) of extract powder by reference to standard curve.

Half-squat or jump squat training under optimum power load conditions to counteract power and speed decrements in Brazilian elite soccer players during the preseason.

PubMed

Loturco, Irineu; Pereira, Lucas A; Kobal, Ronaldo; Zanetti, Vinicius; Gil, Saulo; Kitamura, Katia; Abad, Cesar Cavinato Cal; Nakamura, Fabio Y

2015-01-01

The purpose of this study was to test which specific type of exercise (i.e., jump squat (JS) or half-squat (HS)) is more effective at maintaining speed and power abilities throughout a preseason in soccer players. Twenty-three male soccer players were randomly allocated into two groups: JS and HS. The mean propulsive power, vertical jumping ability, and sprinting performance were evaluated before and after 4 weeks of a preseason period. The optimum power loads for the JS and HS exercises were assessed and were used as load-references. The soccer players performed 10 power oriented training sessions in total. Both JS and HS maintained power in JS and speed abilities (P > 0.05, for main effects and interaction effect) as indicated by ANCOVA. Both groups demonstrated reduced power during HS (ES = -0.76 vs. -0.78, for JS and HS, respectively); both groups improved acceleration (ACC) from 5 to 10 m (ES = 0.52). JS was more effective at reducing the ACC decrements over 0-5 m (ES = -0.38 vs. -0.58, for JS and HS, respectively). The HS group increased squat jump height (ES = 0.76 vs. 0.11, for HS and JS, respectively). In summary, JS is more effective in reducing the ACC capacity over very short sprints while HS is more effective in improving squat jump performance. Both strategies improve ACC over longer distances. New training strategies should be implemented/developed to avoid concurrent training effects between power and endurance adaptations during professional soccer preseasons.

Investigation on the possibility of extracting wave energy from the Texas coast

NASA Astrophysics Data System (ADS)

Haces-Fernandez, Francisco

Due to the great and growing demand of energy consumption in the Texas Coast area, the generation of electricity from ocean waves is considered very important. The combination of the wave energy with offshore wind power is explored as a way to increase power output, obtain synergies, maximize the utilization of assigned marine zones and reduce variability. Previously literature has assessed the wave energy generation, combined with wind in different geographic locations such as California, Ireland and the Azores Island. In this research project, the electric power generation from ocean waves on the Texas Coast was investigated, assessing its potential from the meteorological data provided by five buoys from National Data Buoy Center of the National Oceanic and Atmospheric Administration, considering the Pelamis 750 kW Wave Energy Converter (WEC) and the Vesta V90 3 MW Wind Turbine. The power output from wave energy was calculated for the year 2006 using Matlab, and the results in several locations were considered acceptable in terms of total power output, but with a high temporal variability. To reduce its variability, wave energy was combined with wind energy, obtaining a significant reduction on the coefficient of variation on the power output. A Matlab based interface was created to calculate power output and its variability considering data from longer periods of time.

Comparison of nutritional qualities and antioxidant properties of ready-to-eat fruit-enriched corn based breakfast cereals.

PubMed

Bhavya, S N; Prakash, J

2012-12-01

The study aimed to analyse the nutritional quality, antioxidant components and activity of three varieties of corn based ready-to- eat (RTE) breakfast cereals (BFC) enriched with strawberry, banana and mango. Fruit-enriched corn based breakfast cereals manufactured in India were purchased and ground to obtain homogeneous samples for analysis. The contents of moisture, protein, total fat, dietary fibre, iron, phosphorous, calcium, vitamin C, total carotene, thiamine, riboflavin, in vitro digestible protein, bioaccessible calcium and iron, and digestible starch fractions were determined. The antioxidant components namely, polyphenols, flavonoids and antioxidant activity in different extracts were also determined using total antioxidant, free radical scavenging (2,2-diphenyl-1-picrylhydrazyl) and reducing power assays. The protein and dietary fibre contents in all samples ranged between 4.0-4.6 and 6.4-7.6 g/ 100g respectively. Total iron and vitamin C ranged between 10.7-13.3 mg and 33.2-43.6 mg/100g respectively. Cereals with mango had high total carotene in comparison with other samples. In vitro digestible protein of the processed cereals was low, while bioaccessible calcium (50.2-59.5%) and iron (8.5-15.1%) levels were high due to low oxalates and phytic acid contents. The starch profiles of the breakfast cereals showed high rapidly available glucose and starch digestibility index. Fruit-enriched breakfast cereals showed high polyphenol content in methanol extract (48.6-71.3 mg/100g) and high total antioxidant activity in aqueous extracts. Free radical scavenging and reducing power assay showed high activity in 80% methanol extract. Fruit-enriched breakfast cereals have the potential to be a good source of iron, dietary fibre, vitamin C and total carotene. The fruit-enriched cereals also had high bioaccessible iron and antioxidant activity.

PIC simulation of the vacuum power flow for a 5 terawatt, 5 MV, 1 MA pulsed power system

NASA Astrophysics Data System (ADS)

Liu, Laqun; Zou, Wenkang; Liu, Dagang; Guo, Fan; Wang, Huihui; Chen, Lin

2018-03-01

In this paper, a 5 Terawatt, 5 MV, 1 MA pulsed power system based on vacuum magnetic insulation is simulated by the particle-in-cell (PIC) simulation method. The system consists of 50 100-kV linear transformer drive (LTD) cavities in series, using magnetically insulated induction voltage adder (MIVA) technology for pulsed power addition and transmission. The pulsed power formation and the vacuum power flow are simulated when the system works in self-limited flow and load-limited flow. When the pulsed power system isn't connected to the load, the downstream magnetically insulated transmission line (MITL) works in the self-limited flow, the maximum of output current is 1.14 MA and the amplitude of voltage is 4.63 MV. The ratio of the electron current to the total current is 67.5%, when the output current reached the peak value. When the impedance of the load is 3.0 Ω, the downstream MITL works in the self-limited flow, the maximums of output current and the amplitude of voltage are 1.28 MA and 3.96 MV, and the ratio of the electron current to the total current is 11.7% when the output current reached the peak value. In addition, when the switches are triggered in synchronism with the passage of the pulse power flow, it effectively reduces the rise time of the pulse current.

A Novel Sensor Selection and Power Allocation Algorithm for Multiple-Target Tracking in an LPI Radar Network

PubMed Central

She, Ji; Wang, Fei; Zhou, Jianjiang

2016-01-01

Radar networks are proven to have numerous advantages over traditional monostatic and bistatic radar. With recent developments, radar networks have become an attractive platform due to their low probability of intercept (LPI) performance for target tracking. In this paper, a joint sensor selection and power allocation algorithm for multiple-target tracking in a radar network based on LPI is proposed. It is found that this algorithm can minimize the total transmitted power of a radar network on the basis of a predetermined mutual information (MI) threshold between the target impulse response and the reflected signal. The MI is required by the radar network system to estimate target parameters, and it can be calculated predictively with the estimation of target state. The optimization problem of sensor selection and power allocation, which contains two variables, is non-convex and it can be solved by separating power allocation problem from sensor selection problem. To be specific, the optimization problem of power allocation can be solved by using the bisection method for each sensor selection scheme. Also, the optimization problem of sensor selection can be solved by a lower complexity algorithm based on the allocated powers. According to the simulation results, it can be found that the proposed algorithm can effectively reduce the total transmitted power of a radar network, which can be conducive to improving LPI performance. PMID:28009819

Tannins from Canarium album with potent antioxidant activity*

PubMed Central

Zhang, Liang-liang; Lin, Yi-ming

2008-01-01

The contents of total phenolics and extractable condensed tannins in the leaves, twigs and stem bark of Canarium album were determined. The structural heterogeneity of condensed tannins from stem bark was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance (NMR) analyses. The results show the predominance of signals representative of procyanidins and prodelphinidins. In addition, epicatechin and epigallocatechin polymers with galloylated procyanidin or prodelphinidin were also observed. The tannins were screened for their potential antioxidant activities using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) model systems. Tannins extracted from leaves, twigs and stem bark all showed a very good DPPH radical scavenging activity and ferric reducing power. PMID:18500781

Unattended Sensor System With CLYC Detectors

NASA Astrophysics Data System (ADS)

Myjak, Mitchell J.; Becker, Eric M.; Gilbert, Andrew J.; Hoff, Jonathan E.; Knudson, Christa K.; Landgren, Peter C.; Lee, Samantha F.; McDonald, Benjamin S.; Pfund, David M.; Redding, Rebecca L.; Smart, John E.; Taubman, Matthew S.; Torres-Torres, Carlos R.; Wiseman, Clinton G.

2016-06-01

We have developed an unattended sensor for detecting anomalous radiation sources. The system combines several technologies to reduce size and weight, increase battery lifetime, and improve decision-making capabilities. Sixteen Cs2LiYCl6:Ce (CLYC) scintillators allow for gamma-ray spectroscopy and neutron detection in the same volume. Low-power electronics for readout, high voltage bias, and digital processing reduce the total operating power to 1.7 W. Computationally efficient analysis algorithms perform spectral anomaly detection and isotope identification. When an alarm occurs, the system transmits alarm information over a cellular modem. In this paper, we describe the overall design of the unattended sensor, present characterization results, and compare the performance to stock NaI:Tl and 3He detectors.

Tannins from Canarium album with potent antioxidant activity.

PubMed

Zhang, Liang-liang; Lin, Yi-ming

2008-05-01

The contents of total phenolics and extractable condensed tannins in the leaves, twigs and stem bark of Canarium album were determined. The structural heterogeneity of condensed tannins from stem bark was characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) and nuclear magnetic resonance (NMR) analyses. The results show the predominance of signals representative of procyanidins and prodelphinidins. In addition, epicatechin and epigallocatechin polymers with galloylated procyanidin or prodelphinidin were also observed. The tannins were screened for their potential antioxidant activities using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and ferric reducing/antioxidant power (FRAP) model systems. Tannins extracted from leaves, twigs and stem bark all showed a very good DPPH radical scavenging activity and ferric reducing power.

Unattended Sensor System With CLYC Detectors

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

Myjak, Mitchell J.; Becker, Eric M.; Gilbert, Andrew J.

2016-06-01

We have developed a next-generation unattended sensor for detecting anomalous radiation sources. The system combines several technologies to reduce size and weight, increase battery lifetime, and improve decision-making capabilities. Sixteen Cs2LiYCl6:Ce (CLYC) scintillators allow for gamma-ray spectroscopy and neutron detection in the same volume. Low-power electronics for readout, high voltage bias, and digital processing reduce the total operating power to 1.3 W. Computationally efficient analysis algorithms perform spectral anomaly detection and isotope identification. When an alarm occurs, the system transmits alarm information over a cellular modem. In this paper, we describe the overall design of the unattended sensor, present characterizationmore » results, and compare the performance to stock NaI:Tl and 3He detectors.« less

Effect of five year storage on total phenolic content and antioxidant capacity of almond (Amygdalus communisL.) hull and shell from different genotypes.

PubMed

Moosavi Dolatabadi, Khadijeh Sadat; Dehghan, Gholamreza; Hosseini, Siavash; Jahanban Esfahlan, Ali

2015-01-01

Almond (Prunus amygdalus) hull and shell are agricultural by-products that are a source of phenolic compounds.The processing of almond produce shell and hull, accounts for more than 50% by dry weight of the almond fruits. Recently, more studies have focused on the influence of storage conditions and postharvest handling on the nutritional quality of fruits, especially the antioxidant phenolics. In this study, influence of long-term storage (five years) on the total phenolic and antioxidant capacity of almond hull and shell from different genotypes was evaluated. The fruits of subjected genotypes were collected and their hull and shell were separated. They were dried and reduced to fine powder. This powder stored at room temperature for five years. The total phenolic content (TPC) and bioactivities (antioxidant potential: DPPH and ABTS radical scavenging and reducing power) of extracts were evaluated using spectrophotometric methods. It was found that TPC content and bioactivity levels in the stored almond hull and shell were different, compared to the hulls and shells which were evaluated in 2007. S1-4 genotype had the highest TPC and reducing power in its hull and shell.Low correlation coefficient was observed between phenolic content and the DPPH radical scavenging percentage in hull and shell extract. For the first time, results of this investigation showed that storage can influence the antioxidant and antiradical potential of almond hull and shell.

A Novel Multilevel DC - AC Converter from Green Energy Power Generators Using Step-Square Waving and PWM Technique

NASA Astrophysics Data System (ADS)

Fajingbesi, F. E.; Midi, N. S.; Khan, S.

2017-06-01

Green energy sources or renewable energy system generally utilize modular approach in their design. This sort of power sources are generally in DC form or in single cases AC. Due to high fluctuation in the natural origin of this energy (wind & solar) source they are stored as DC. DC power however are difficult to transfer over long distances hence DC to AC converters and storage system are very important in green energy system design. In this work we have designed a novel multilevel DC to AC converter that takes into account the modular design of green energy systems. A power conversion efficiency of 99% with reduced total harmonic distortion (THD) was recorded from our simulated system design.

Airframe Noise Reduction Studies and Clean-Airframe Noise Investigation

NASA Technical Reports Server (NTRS)

Fink, M. R.; Bailey, D. A.

1980-01-01

Acoustic wind tunnel tests were conducted of a wing model with modified leading edge slat and trailing edge flap. The modifications were intended to reduce the surface pressure response to convected turbulence and thereby reduce the airframe noise without changing the lift at constant incidence. Tests were conducted at 70.7 and 100 m/sec airspeeds, with Reynolds numbers 1.5 x 10 to the 6th power and 2.1 x 10 to the 6th power. Considerable reduction of noise radiation from the side edges of a 40 deflection single slotted flap was achieved by modification to the side edge regions or the leading edge region of the flap panel. Total far field noise was reduced 2 to 3 dB over several octaves of frequency. When these panels were installed as the aft panel of a 40 deg deflection double slotted flap, 2 dB noise reduction was achieved.

Mitigation of cross-beam energy transfer in symmetric implosions on OMEGA using wavelength detuning

DOE PAGES

Edgell, D. H.; Follett, R. K.; Igumenshchev, I. V.; ...

2017-06-13

The effects of frequency detuning laser beams in direct-drive symmetric implosions were investigated with a 3-D cross-beam energy transfer (CBET) model. Our model shows that interactions between beams with relative angles between 45° and 90° are most significant for CBET in OMEGA direct-drive implosions. There is no net exchange in power between beams but there is significant redistribution of power from the ingoing central portion of the beam profile to the outgoing edge as it is exiting the plasma, reducing the total absorbed power. Furthermore, redistribution of laser power because of CBET increases the root-mean-square (rms) absorption nonuniformity by anmore » order of magnitude. CBET mitigation by shifting relative wavelengths of three groups of laser beams fed by each of the different beamlines was modeled. At an on-target wavelength shift of Δλ ~ 10 Å, the total laser absorption was maximized, and the rms absorption nonuniformity was near minimum. In order to completely decouple the three groups of beams from each other requires wavelength shifts Δλ > 30 Å.« less

Mitigation of cross-beam energy transfer in symmetric implosions on OMEGA using wavelength detuning

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

Edgell, D. H.; Follett, R. K.; Igumenshchev, I. V.

The effects of frequency detuning laser beams in direct-drive symmetric implosions were investigated with a 3-D cross-beam energy transfer (CBET) model. Our model shows that interactions between beams with relative angles between 45° and 90° are most significant for CBET in OMEGA direct-drive implosions. There is no net exchange in power between beams but there is significant redistribution of power from the ingoing central portion of the beam profile to the outgoing edge as it is exiting the plasma, reducing the total absorbed power. Furthermore, redistribution of laser power because of CBET increases the root-mean-square (rms) absorption nonuniformity by anmore » order of magnitude. CBET mitigation by shifting relative wavelengths of three groups of laser beams fed by each of the different beamlines was modeled. At an on-target wavelength shift of Δλ ~ 10 Å, the total laser absorption was maximized, and the rms absorption nonuniformity was near minimum. In order to completely decouple the three groups of beams from each other requires wavelength shifts Δλ > 30 Å.« less

Microgrid Analysis Tools Summary

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

Jimenez, Antonio; Haase, Scott G; Mathur, Shivani

2018-03-05

The over-arching goal of the Alaska Microgrid Partnership is to reduce the use of total imported fuel into communities to secure all energy services by at least 50% in Alaska's remote microgrids without increasing system life cycle costs while also improving overall system reliability, security, and resilience. One goal of the Alaska Microgrid Partnership is to investigate whether a combination of energy efficiency and high-contribution (from renewable energy) power systems can reduce total imported energy usage by 50% while reducing life cycle costs and improving reliability and resiliency. This presentation provides an overview of the following four renewable energy optimizationmore » tools. Information is from respective tool websites, tool developers, and author experience. Distributed Energy Resources Customer Adoption Model (DER-CAM) Microgrid Design Toolkit (MDT) Renewable Energy Optimization (REopt) Tool Hybrid Optimization Model for Electric Renewables (HOMER).« less

In-vitro Antioxidant Activities of the Ethanolic Extracts of Some Contained-Allantoin Plants

PubMed Central

Selamoglu, Zeliha; Dusgun, Cihan; Akgul, Hasan; Gulhan, Mehmet Fuat

2017-01-01

It has been investigated the in-vitro antioxidant properties of ethanol extracts of the contained-allantoin plants in this study. Contained-allantoined plant samples Plantago lanceolata, Plantago major, Robinia pseudoacacia, Platanus orientalis and Aesculus hippocastanum were tested at different concentrations. The antioxidant activities of plant samples were analysed by 1,1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method, cupric reducing antioxidant capacity (CUPRAC), reducing power assay and β-carotene bleaching method. Plantago major plant showed the highest antioxidant capacity compared to other plant extracts in results of the in-vitro assays including 1,1- diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method with 90.25 %, cupric reducing antioxidant capacity (CUPRAC) with 1.789 %, reducing power assay (FRAP) with 1.321 % and β-carotene bleaching method with 78.01 % in 1 mg/mL. The lowest antioxidant activity was determined in Robinia pseudoacacia plant. In conclusion, allantoin shows antioxidant properties and it has the positive effect on total antioxidant capacity.

Where is the ideal location for a US East Coast offshore grid?

NASA Astrophysics Data System (ADS)

Dvorak, Michael J.; Stoutenburg, Eric D.; Archer, Cristina L.; Kempton, Willett; Jacobson, Mark Z.

2012-03-01

This paper identifies the location of an “ideal” offshore wind energy (OWE) grid on the U.S. East Coast that would (1) provide the highest overall and peak-time summer capacity factor, (2) use bottom-mounted turbine foundations (depth ≤50 m), (3) connect regional transmissions grids from New England to the Mid-Atlantic, and (4) have a smoothed power output, reduced hourly ramp rates and hours of zero power. Hourly, high-resolution mesoscale weather model data from 2006-2010 were used to approximate wind farm output. The offshore grid was located in the waters from Long Island, New York to the Georges Bank, ≈450 km east. Twelve candidate 500 MW wind farms were located randomly throughout that region. Four wind farms (2000 MW total capacity) were selected for their synergistic meteorological characteristics that reduced offshore grid variability. Sites likely to have sea breezes helped increase the grid capacity factor during peak time in the spring and summer months. Sites far offshore, dominated by powerful synoptic-scale storms, were included for their generally higher but more variable power output. By interconnecting all 4 farms via an offshore grid versus 4 individual interconnections, power was smoothed, the no-power events were reduced from 9% to 4%, and the combined capacity factor was 48% (gross). By interconnecting offshore wind energy farms ≈450 km apart, in regions with offshore wind energy resources driven by both synoptic-scale storms and mesoscale sea breezes, substantial reductions in low/no-power hours and hourly ramp rates can be made.

Posterior corneal astigmatism in refractive lens exchange surgery.

PubMed

Rydström, Elin; Westin, Oscar; Koskela, Timo; Behndig, Anders

2016-05-01

To assess the anterior, posterior and total corneal spherical and astigmatic powers in patients undergoing refractive lens exchange (RLE) surgery. In 402 consecutive patients planned for RLE at Koskelas Eye Clinic, Luleå, Sweden, right eye data from pre- and postoperative subjective refraction, preoperative IOLMaster(®) biometry and Pentacam HR(®) measurements were collected. Postoperative Pentacam HR(®) data were collected for 54 of the patients. The spherical and astigmatic powers of the anterior and posterior corneal surfaces and for the total cornea were assessed and compared, and surgically, induced astigmatism was calculated using vector analysis. The spherical power of the anterior corneal surface was 48.18 ± 1.69D with an astigmatic power of 0.83 ± 0.54D. The corresponding values for the posterior surface were -6.05 ± 2,52D and 0.26 ± 0.15D, respectively. The total corneal spherical power calculated with ray tracing was 42.47 ± 2.89D with a 0.72 ± 0.48D astigmatic power, and the corresponding figures obtained by estimating the posterior corneal surface were 43.25 ± 1.51D (p < 0.001) with a 0.75 ± 0.49D astigmatic power (p = 0.003). In eyes with anterior astigmatism with-the-rule, the total corneal astigmatism is overestimated if the posterior corneal surface is estimated; in eyes, with against-the-rule astigmatism it is underestimated. Had the posterior corneal surface been measured in this material, 14.7% of the patients would have received a spheric instead of a toric IOL, or vice versa. Estimating the posterior corneal surface in RLE patients leads to systematic measurement errors that can be reduced by measuring the posterior surface. Such an approach can potentially increase the refractive outcome accuracy in RLE surgery. © 2016 Acta Ophthalmologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

Active Vibration Control for Helicopter Interior Noise Reduction Using Power Minimization

NASA Technical Reports Server (NTRS)

Mendoza, J.; Chevva, K.; Sun, F.; Blanc, A.; Kim, S. B.

2014-01-01

This report describes work performed by United Technologies Research Center (UTRC) for NASA Langley Research Center (LaRC) under Contract NNL11AA06C. The objective of this program is to develop technology to reduce helicopter interior noise resulting from multiple gear meshing frequencies. A novel active vibration control approach called Minimum Actuation Power (MAP) is developed. MAP is an optimal control strategy that minimizes the total input power into a structure by monitoring and varying the input power of controlling sources. MAP control was implemented without explicit knowledge of the phasing and magnitude of the excitation sources by driving the real part of the input power from the controlling sources to zero. It is shown that this occurs when the total mechanical input power from the excitation and controlling sources is a minimum. MAP theory is developed for multiple excitation sources with arbitrary relative phasing for single or multiple discrete frequencies and controlled by a single or multiple controlling sources. Simulations and experimental results demonstrate the feasibility of MAP for structural vibration reduction of a realistic rotorcraft interior structure. MAP control resulted in significant average global vibration reduction of a single frequency and multiple frequency excitations with one controlling actuator. Simulations also demonstrate the potential effectiveness of the observed vibration reductions on interior radiated noise.

Total Phenol Content and In Vitro Antioxidant Potential of Helicanthus elastica (Desr.) Danser-A Less-explored Indian Mango Mistletoe

PubMed Central

Sunil Kumar, Koppala Narayana; Saraswathy, Ariyamuthu; Amerjothy, Swaminathan; Susan, Thomas; Ravishankar, Basaviah

2014-01-01

Natural products are an important source of antioxidant molecules like tannins, phenolic compounds, flavonoids, etc., Helicanthus elastica (Desr.) Danser (Loranthaceae) is one such plant belonging to the category of mistletoe, and grows commonly on the mango trees in India. In the present study, an attempt has been made to assess the antioxidant properties of the plant. Ethanol extract of H. elastica growing on mango tree was studied using different in vitro models. Shade-dried whole plant material was extracted with ethanol by cold percolation. Fifty milligrams of the alcohol extract of H. elastica was weighed and dissolved in 10 ml of methanol. The resultant 5 mg/ml solution was suitably diluted to obtain different concentrations. Total phenol content, reducing power assay, and scavenging of free radicals like nitric oxide, hydroxyl, hydrogen peroxide, and 1,1-diphenyl-2-picrylhydrazyl were studied by standardized in vitro chemical methods using ascorbic acid as the standard. The total phenol content of the plant was found to be 1.89% w/w. The extract showed good reducing power as well as scavenging of free radicals (nitric oxide, hydroxyl, superoxide anion, and hydrogen peroxide) at concentrations ranging from 5 to 100 μg/ml. The study revealed the antioxidant potential of H. elastica. PMID:25379473

Evaluation of nutritional composition and antioxidant activity of Borage (Echium amoenum) and Valerian (Valerian officinalis).

PubMed

Adel Pilerood, Shirin; Prakash, Jamuna

2014-05-01

The nutritional composition and antioxidant activity (in aqueose and solvent extracts) of two medicinal plants of Iranian origin Borage (Echium amoenum) and Valerian (Valerian officinalis) used as tea were determined. Samples were analyzed for antioxidant components viz. polyphenols, vitamin C, β carotene, flavonoids, anthocyanins and tannins. Antioxidant assays such as free radical scavenging activity, reducing power and total antioxidant activity were carried out for ethanol, methanol, acetone, 80% methanol and 80% ethanolic extracts. In borage highest and least activity was observed in water and acetone extract respectively in all assays. In Valerian, 80% methanolic extract showed highest activity in reducing power and free radical scavenging activity assay. Total polyphenols in borage and valerian were 1,220 and 500 mg in ethanolic extracts and 25 and 130 mg in acetonic extracts respectively. Total carotenoids and vitamin C contents were 31.6 and 133.69 mg and 51.2 and 44.87 mg for borage and valerian respectively. Highest amount of tannins were extracted in 80% methanolic extract. It can be concluded that borage and valerian exhibited antioxidant activity in all extracts. The antioxidant activity could be attributed to their polyphenol and tannin and flavonoids contents. In all assays borage showed higher activity than valerian.

Extraction, characterization and biological studies of phytochemicals from Mammea suriga.

PubMed

Poojary, Mahesha M; Vishnumurthy, Kanivebagilu A; Vasudeva Adhikari, Airody

2015-06-01

The present work involves extraction of phytochemicals from the root bark of a well-known Indian traditional medicinal plant, viz. Mammea suriga , with various solvents and evaluation of their in vitro antimicrobial and antioxidant activities using standard methods. The phytochemical analysis indicates the presence of some interesting secondary metabolites like flavonoids, cardiac glycosides, alkaloids, saponins and tannins in the extracts. Also, the solvent extracts displayed promising antimicrobial activity against Staphylococcus aureus , Bacillus subtilis and Cryptococcus neoformans with inhibition zone in a range of 20-33 mm. Further, results of their antioxidant screening revealed that aqueous extract (with IC 50 values of 111.51±1.03 and 31.05±0.92 μg/mL in total reducing power assay and DPHH radical scavenging assay, respectively) and ethanolic extract (with IC 50 values of 128.00±1.01 and 33.25±0.89 μg/mL in total reducing power assay and DPHH radical scavenging assay, respectively) were better antioxidants than standard ascorbic acid. Interestingly, FT-IR analysis of each extract established the presence of various biologically active functional groups in it.

Enhanced succinic acid production from corncob hydrolysate by microbial electrolysis cells.

PubMed

Zhao, Yan; Cao, Weijia; Wang, Zhen; Zhang, Bowen; Chen, Kequan; Ouyang, Pingkai

2016-02-01

In this study, Actinobacillus succinogenes NJ113 microbial electrolysis cells (MECs) were used to enhance the reducing power responsible for succinic acid production from corncob hydrolysate. During corncob hydrolysate fermentation, electric MECs resulted in a 1.31-fold increase in succinic acid production and a 1.33-fold increase in the reducing power compared with those in non-electric MECs. When the hydrolysate was detoxified by combining Ca(OH)2, NaOH, and activated carbon, succinic acid production increased from 3.47 to 6.95 g/l. Using a constant potential of -1.8 V further increased succinic acid production to 7.18 g/l. A total of 18.09 g/l of succinic acid and a yield of 0.60 g/g total sugar were obtained after a 60-h fermentation when NaOH was used as a pH regulator. The improved succinic acid yield from corncob hydrolysate fermentation using A. succinogenes NJ113 in electric MECs demonstrates the great potential of using biomass as a feedstock to cost-effectively produce succinate. Copyright © 2015 Elsevier Ltd. All rights reserved.

Antioxidant activities, metal contents, total phenolics and flavonoids of seven Morchella species.

PubMed

Gursoy, Nevcihan; Sarikurkcu, Cengiz; Cengiz, Mustafa; Solak, M Halil

2009-09-01

Seven Morchella species were analyzed for their antioxidant activities in different test systems namely beta-carotene/linoleic acid, DPPH, reducing power, chelating effect and scavenging effect (%) on the stable ABTS*(+), in addition to their heavy metals, total phenolic and flavonoid contents. In beta-carotene/linoleic acid system, the most active mushrooms were M. esculenta var. umbrina and M.angusticeps. In the case of DPPH, methanol extract of M. conica showed high antioxidant activity. The reducing power of the methanol extracts of mushrooms increased with concentration. Chelating capacity of the extracts was also increased with the concentration. On the other hand, in 40 microg ml(-1) concentration, methanol extract of M. conica, exhibited the highest radical scavenging activity (78.66+/-2.07%) when reacted with the ABTS*(+) radical. Amounts of seven elements (Cu, Mn, Co, Zn, Fe, Ca, and Mg) and five heavy metals (Ni, Pb, Cd, Cr, and Al) were also determined in all species. M. conica was found to have the highest phenolic content among the samples. Flavonoid content of M. rotunda was also found superior (0.59+/-0.01 microg QEs/mg extract).

Sympathovagal imbalance in hyperthyroidism.

PubMed

Burggraaf, J; Tulen, J H; Lalezari, S; Schoemaker, R C; De Meyer, P H; Meinders, A E; Cohen, A F; Pijl, H

2001-07-01

We assessed sympathovagal balance in thyrotoxicosis. Fourteen patients with Graves' hyperthyroidism were studied before and after 7 days of treatment with propranolol (40 mg 3 times a day) and in the euthyroid state. Data were compared with those obtained in a group of age-, sex-, and weight-matched controls. Autonomic inputs to the heart were assessed by power spectral analysis of heart rate variability. Systemic exposure to sympathetic neurohormones was estimated on the basis of 24-h urinary catecholamine excretion. The spectral power in the high-frequency domain was considerably reduced in hyperthyroid patients, indicating diminished vagal inputs to the heart. Increased heart rate and mid-frequency/high-frequency power ratio in the presence of reduced total spectral power and increased urinary catecholamine excretion strongly suggest enhanced sympathetic inputs in thyrotoxicosis. All abnormal features of autonomic balance were completely restored to normal in the euthyroid state. beta-Adrenoceptor antagonism reduced heart rate in hyperthyroid patients but did not significantly affect heart rate variability or catecholamine excretion. This is in keeping with the concept of a joint disruption of sympathetic and vagal inputs to the heart underlying changes in heart rate variability. Thus thyrotoxicosis is characterized by profound sympathovagal imbalance, brought about by increased sympathetic activity in the presence of diminished vagal tone.

Power Balance and Impurity Studies in TCS

NASA Astrophysics Data System (ADS)

Grossnickle, J. A.; Pietrzyk, Z. A.; Vlases, G. C.

2003-10-01

A "zero-dimension" power balance model was developed based on measurements of absorbed power, radiated power, absolute D_α, temperature, and density for the TCS device. Radiation was determined to be the dominant source of power loss for medium to high density plasmas. The total radiated power was strongly correlated with the Oxygen line radiation. This suggests Oxygen is the dominant radiating species, which was confirmed by doping studies. These also extrapolate to a Carbon content below 1.5%. Determining the source of the impurities is an important question that must be answered for the TCS upgrade. Preliminary indications are that the primary sources of Oxygen are the stainless steel end cones. A Ti gettering system is being installed to reduce this Oxygen source. A field line code has been developed for use in tracking where open field lines terminate on the walls. Output from this code is also used to generate grids for an impurity tracking code.

Gibberellic acid (GA3) induced changes in proanthocyanidins and malt quality of two- and six-row husked barleys.

PubMed

Yadav, S K; Luthra, Y P; Sood, D R; Aggarwal, N K

2000-01-01

Analysis of husked barleys for proanthocyanidins and malt quality attributes has shown that not a single variety is free of proanthocyanidins. The proanthocyanidins in barley grains varied from 3.85 to 4.94 mg/g as catechin equivalent. The concentration of proanthocyanidins decreased, while total soluble sugars, reducing sugars, diastatic power and beta-amylase activity increased during maltings as well as with exogenous gibberellic acid (GA3) application. Alfa 93 (two-row) and RD2560 (six-row) varieties appeared to be superior for malting and brewing purposes on the basis of proanthocyanidins, total phenols, diastatic power and beta-amylase activity. It is suggested that exogenous application of GA3 at 15 ppm may be useful for producing good quality malt from barley grains.

Winnebago Tribe Solar Project

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

Nieman, Autumn

2016-02-26

The strategy of the Solar Project was to reduce fuel use within two years by a roof mounted photovoltaic system. The police/fire building is completely powered by electricity. The renewable energy system we have selected has a power capacity of 23kW and the ability to export 44.3 MWh. We anticipate 32.55% kWh energy savings, an excess of the required 30% reduction, in the building’s total fuel use based on the most current 12 months of data (2012). The solar electric system is a grid-tie, ballast mounted on a flat roof over the police/fire station. The solar electric system includes 280more » Watt modules for a nominal total of 22.80 kW. Approximately 84 modules are ballast mounted to the flat roof facing south.« less

On-Chip Neural Data Compression Based On Compressed Sensing With Sparse Sensing Matrices.

PubMed

Zhao, Wenfeng; Sun, Biao; Wu, Tong; Yang, Zhi

2018-02-01

On-chip neural data compression is an enabling technique for wireless neural interfaces that suffer from insufficient bandwidth and power budgets to transmit the raw data. The data compression algorithm and its implementation should be power and area efficient and functionally reliable over different datasets. Compressed sensing is an emerging technique that has been applied to compress various neurophysiological data. However, the state-of-the-art compressed sensing (CS) encoders leverage random but dense binary measurement matrices, which incur substantial implementation costs on both power and area that could offset the benefits from the reduced wireless data rate. In this paper, we propose two CS encoder designs based on sparse measurement matrices that could lead to efficient hardware implementation. Specifically, two different approaches for the construction of sparse measurement matrices, i.e., the deterministic quasi-cyclic array code (QCAC) matrix and -sparse random binary matrix [-SRBM] are exploited. We demonstrate that the proposed CS encoders lead to comparable recovery performance. And efficient VLSI architecture designs are proposed for QCAC-CS and -SRBM encoders with reduced area and total power consumption.

Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

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

Dubey, P. K., E-mail: premkdubey@gmail.com; Kumar, Yudhisther; Gupta, Reeta

2014-05-15

The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occursmore » at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.« less

Measurement of total ultrasonic power using thermal expansion and change in buoyancy of an absorbing target

NASA Astrophysics Data System (ADS)

Dubey, P. K.; Kumar, Yudhisther; Gupta, Reeta; Jain, Anshul; Gohiya, Chandrashekhar

2014-05-01

The Radiation Force Balance (RFB) technique is well established and most widely used for the measurement of total ultrasonic power radiated by ultrasonic transducer. The technique is used as a primary standard for calibration of ultrasonic transducers with relatively fair uncertainty in the low power (below 1 W) regime. In this technique, uncertainty comparatively increases in the range of few watts wherein the effects such as thermal heating of the target, cavitations, and acoustic streaming dominate. In addition, error in the measurement of ultrasonic power is also caused due to movement of absorber at relatively high radiated force which occurs at high power level. In this article a new technique is proposed which does not measure the balance output during transducer energized state as done in RFB. It utilizes the change in buoyancy of the absorbing target due to local thermal heating. The linear thermal expansion of the target changes the apparent mass in water due to buoyancy change. This forms the basis for the measurement of ultrasonic power particularly in watts range. The proposed method comparatively reduces uncertainty caused by various ultrasonic effects that occur at high power such as overshoot due to momentum of target at higher radiated force. The functionality of the technique has been tested and compared with the existing internationally recommended RFB technique.

Space Shuttle power extension package

NASA Technical Reports Server (NTRS)

Loftus, J. P., Jr.; Craig, J. W.

1980-01-01

A modification kit for the Space Transportation System (STS) Orbiter is proposed to provide more power and mission duration for payloads. The power extension package (PEP), a flexible-substrate solar array deployed on the Space Shuttle Orbiter remote manipulator system, can provide as much as 29 kW total power for durations of 10 to 48 days. The kit is installed only for those flights which require enhanced power or duration. The PEP is made possible by development of the flexible-substrate array technology and, in itself, contributes to the technology base for the use of large area solar cells. Modifications to the Orbiter thermal control and life support systems to improve heat balance and to reduce consumables are proposed. The changes consist of repositioning the Orbiter forward radiators and replacing the lithium hydroxide scrubber with a regenerable solid amine.

Selective harmonic elimination strategy in eleven level inverter for PV system with unbalanced DC sources

NASA Astrophysics Data System (ADS)

Ghoudelbourk, Sihem.; Dib, D.; Meghni, B.; Zouli, M.

2017-02-01

The paper deals with the multilevel converters control strategy for photovoltaic system integrated in distribution grids. The objective of the proposed work is to design multilevel inverters for solar energy applications so as to reduce the Total Harmonic Distortion (THD) and to improve the power quality. The multilevel inverter power structure plays a vital role in every aspect of the power system. It is easier to produce a high-power, high-voltage inverter with the multilevel structure. The topologies of multilevel inverter have several advantages such as high output voltage, lower total harmonic distortion (THD) and reduction of voltage ratings of the power semiconductor switching devices. The proposed control strategy ensures an implementation of selective harmonic elimination (SHE) modulation for eleven levels. SHE is a very important and efficient strategy of eliminating selected harmonics by judicious selection of the firing angles of the inverter. Harmonics elimination technique eliminates the need of the expensive low pass filters in the system. Previous research considered that constant and equal DC sources with invariant behavior; however, this research extends earlier work to include variant DC sources, which are typical of lead-acid batteries when used in system PV. This Study also investigates methods to minimize the total harmonic distortion of the synthesized multilevel waveform and to help balance the battery voltage. The harmonic elimination method was used to eliminate selected lower dominant harmonics resulting from the inverter switching action.

Optimizing Data Centre Energy and Environmental Costs

NASA Astrophysics Data System (ADS)

Aikema, David Hendrik

Data centres use an estimated 2% of US electrical power which accounts for much of their total cost of ownership. This consumption continues to grow, further straining power grids attempting to integrate more renewable energy. This dissertation focuses on assessing and reducing data centre environmental and financial costs. Emissions of projects undertaken to lower the data centre environmental footprints can be assessed and the emission reduction projects compared using an ISO-14064-2-compliant greenhouse gas reduction protocol outlined herein. I was closely involved with the development of the protocol. Full lifecycle analysis and verifying that projects exceed business-as-usual expectations are addressed, and a test project is described. Consuming power when it is low cost or when renewable energy is available can be used to reduce the financial and environmental costs of computing. Adaptation based on the power price showed 10--50% potential savings in typical cases, and local renewable energy use could be increased by 10--80%. Allowing a fraction of high-priority tasks to proceed unimpeded still allows significant savings. Power grid operators use mechanisms called ancillary services to address variation and system failures, paying organizations to alter power consumption on request. By bidding to offer these services, data centres may be able to lower their energy costs while reducing their environmental impact. If providing contingency reserves which require only infrequent action, savings of up to 12% were seen in simulations. Greater power cost savings are possible for those ceding more control to the power grid operator. Coordinating multiple data centres adds overhead, and altering at which data centre requests are processed based on changes in the financial or environmental costs of power is likely to increase this overhead. Tests of virtual machine migrations showed that in some cases there was no visible increase in power use while in others power use rose by 20--30W. Estimates of how migration was likely to impact other services used in current cloud environments were derived.

An experimental study of ultrasonic vibration and the penetration of granular material

PubMed Central

Firstbrook, David; Worrall, Kevin; Timoney, Ryan; Suñol, Francesc; Gao, Yang

2017-01-01

This work investigates the potential use of direct ultrasonic vibration as an aid to penetration of granular material. Compared with non-ultrasonic penetration, required forces have been observed to reduce by an order of magnitude. Similarly, total consumed power can be reduced by up to 27%, depending on the substrate and ultrasonic amplitude used. Tests were also carried out in high-gravity conditions, displaying a trend that suggests these benefits could be leveraged in lower gravity regimes. PMID:28293134

A new alternative fuel for reduction of polycyclic aromatic hydrocarbon and particulate matter emissions from diesel engines.

PubMed

Yuan, Chung-Shin; Lin, Hsun-Yu; Lee, Wen-Jhy; Lin, Yuan-Chung; Wu, Tser-Son; Chen, Kung-Fu

2007-04-01

This study investigated the emissions of polycyclic aromatic hydrocarbons (PAHs), carcinogenic potential of PAH and particulate matter (PM), brake-specific fuel consumption (BSFC), and power from diesel engines under transient cycle testing of six test fuels: premium diesel fuel (PDF), B100 (100% palm biodiesel), B20 (20% palm biodiesel + 80% PDF), BP9505 (95% paraffinic fuel + 5% palm biodiesel), BP8020 (80% paraffinic fuel + 20% palm biodiesel), and BP100 (100% paraffinic fuel; Table 1). Experimental results indicated that B100, BP9505, BP8020, and BP100 were much safer when stored than PDF. However, we must use additives so that B100 and BP100 will not gel as quickly in a cold zone. Using B100, BP9505, and BP8020 instead of PDF reduced PM, THC, and CO emissions dramatically but increased CO2 slightly because of more complete combustion. The CO2-increased fraction of BP9505 was the lowest among test blends. Furthermore, using B100, B20, BP9505, and BP8020 as alternative fuels reduced total PAHs and total benzo[a]pyrene equivalent concentration (total BaPeq) emissions significantly. BP9505 had the lowest decreased fractions of power and torque and increased fraction of BSFC. These experimental results implied that BP9505 is feasible for traveling diesel vehicles. Moreover, paraffinic fuel will likely be a new alternative fuel in the future. Using BP9505 instead of PDF decreased PM (22.8%), THC (13.4%), CO (25.3%), total PAHs (88.9%), and total BaPeq (88.1%) emissions significantly.

OVERMODED HIGH-POWER RF MAGNETIC SWITCHES AND CIRCULATORS

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

Tantawi, Sami

2002-08-20

We present design methodology for active rf magnetic components which are suitable for pulse compression systems of future X-band linear colliders. These components comprise an array of active elements arranged together so that the total electromagnetic field is reduced and the power handling capabilities are increased. The active element of choice is a magnetic material (garnet), which can be switched by changing a biasing magnetic field. A novel design allows these components to operate in the low loss circular waveguide mode TE{sub 01}. We describe the design methodology, the switching elements and circuits.

Accelerating an Ordered-Subset Low-Dose X-Ray Cone Beam Computed Tomography Image Reconstruction with a Power Factor and Total Variation Minimization.

PubMed

Huang, Hsuan-Ming; Hsiao, Ing-Tsung

2016-01-01

In recent years, there has been increased interest in low-dose X-ray cone beam computed tomography (CBCT) in many fields, including dentistry, guided radiotherapy and small animal imaging. Despite reducing the radiation dose, low-dose CBCT has not gained widespread acceptance in routine clinical practice. In addition to performing more evaluation studies, developing a fast and high-quality reconstruction algorithm is required. In this work, we propose an iterative reconstruction method that accelerates ordered-subsets (OS) reconstruction using a power factor. Furthermore, we combine it with the total-variation (TV) minimization method. Both simulation and phantom studies were conducted to evaluate the performance of the proposed method. Results show that the proposed method can accelerate conventional OS methods, greatly increase the convergence speed in early iterations. Moreover, applying the TV minimization to the power acceleration scheme can further improve the image quality while preserving the fast convergence rate.

Advanced combined iodine dispenser and detector. [for microorganism annihilation in potable water

NASA Technical Reports Server (NTRS)

Lantz, J. B.; Schubert, F. H.; Jensen, F. C.; Powell, J. D.

1977-01-01

A total weight of 1.23 kg (2.7 lb), a total volume of 1213 cu m (74 cu in), and an average power consumption of 5.5W was achieved in the advanced combined iodine dispenser/detector by integrating the detector with the iodine source, arranging all iodinator components within a compact package and lowering the parasitic power to the detector and electronics circuits. These achievements surpassed the design goals of 1.36 kg (3.0 lb), 1671 cu m (102 cu in) and 8W. The reliability and maintainability were improved by reducing the detector lamp power, using an interchangeable lamp concept, making the electronic circuit boards easily accessible, providing redundant water seals and improving the accessibility to the iodine accumulator for refilling. The system was designed to iodinate (to 5 ppm iodine) the fuel cell water generated during 27 seven-day orbiter missions (equivalent to 18,500 kg (40,700 lb) of water) before the unit must be recharged with iodine crystals.

Analysis of automatic repeat request methods for deep-space downlinks

NASA Technical Reports Server (NTRS)

Pollara, F.; Ekroot, L.

1995-01-01

Automatic repeat request (ARQ) methods cannot increase the capacity of a memoryless channel. However, they can be used to decrease the complexity of the channel-coding system to achieve essentially error-free transmission and to reduce link margins when the channel characteristics are poorly predictable. This article considers ARQ methods on a power-limited channel (e.g., the deep-space channel), where it is important to minimize the total power needed to transmit the data, as opposed to a bandwidth-limited channel (e.g., terrestrial data links), where the spectral efficiency or the total required transmission time is the most relevant performance measure. In the analysis, we compare the performance of three reference concatenated coded systems used in actual deep-space missions to that obtainable by ARQ methods using the same codes, in terms of required power, time to transmit with a given number of retransmissions, and achievable probability of word error. The ultimate limits of ARQ with an arbitrary number of retransmissions are also derived.

Accelerating an Ordered-Subset Low-Dose X-Ray Cone Beam Computed Tomography Image Reconstruction with a Power Factor and Total Variation Minimization

PubMed Central

Huang, Hsuan-Ming; Hsiao, Ing-Tsung

2016-01-01

In recent years, there has been increased interest in low-dose X-ray cone beam computed tomography (CBCT) in many fields, including dentistry, guided radiotherapy and small animal imaging. Despite reducing the radiation dose, low-dose CBCT has not gained widespread acceptance in routine clinical practice. In addition to performing more evaluation studies, developing a fast and high-quality reconstruction algorithm is required. In this work, we propose an iterative reconstruction method that accelerates ordered-subsets (OS) reconstruction using a power factor. Furthermore, we combine it with the total-variation (TV) minimization method. Both simulation and phantom studies were conducted to evaluate the performance of the proposed method. Results show that the proposed method can accelerate conventional OS methods, greatly increase the convergence speed in early iterations. Moreover, applying the TV minimization to the power acceleration scheme can further improve the image quality while preserving the fast convergence rate. PMID:27073853

Drought Resilience of Water Supplies for Shale Gas Extraction and Related Power Generation in Texas

NASA Astrophysics Data System (ADS)

Reedy, R. C.; Scanlon, B. R.; Nicot, J. P.; Uhlman, K.

2014-12-01

There is considerable concern about water availability to support energy production in Texas, particularly considering that many of the shale plays are in semiarid areas of Texas and the state experienced the most extreme drought on record in 2011. The Eagle Ford shale play provides an excellent case study. Hydraulic fracturing water use for shale gas extraction in the play totaled ~ 12 billion gallons (bgal) in 2012, representing ~7 - 10% of total water use in the 16 county play area. The dominant source of water is groundwater which is not highly vulnerable to drought from a recharge perspective because water is primarily stored in the confined portion of aquifers that were recharged thousands of years ago. Water supply drought vulnerability results primarily from increased water use for irrigation. Irrigation water use in the Eagle Ford play was 30 billion gallons higher in the 2011 drought year relative to 2010. Recent trends toward increased use of brackish groundwater for shale gas extraction in the Eagle Ford also reduce pressure on fresh water resources. Evaluating the impacts of natural gas development on water resources should consider the use of natural gas in power generation, which now represents 50% of power generation in Texas. Water consumed in extracting the natural gas required for power generation is equivalent to ~7% of the water consumed in cooling these power plants in the state. However, natural gas production from shale plays can be overall beneficial in terms of water resources in the state because natural gas combined cycle power generation decreases water consumption by ~60% relative to traditional coal, nuclear, and natural gas plants that use steam turbine generation. This reduced water consumption enhances drought resilience of power generation in the state. In addition, natural gas combined cycle plants provide peaking capacity that complements increasing renewable wind generation which has no cooling water requirement. However, water savings related to power generation is not collocated with water used for shale gas extraction. Analysis of drought impacts on water energy interdependence should consider both water for energy extraction and power generation to assess net impacts.

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Spectral and energy parameters of multiband barrier-discharge KrBr excilamps

NASA Astrophysics Data System (ADS)

Avdeev, S. M.; Erofeev, M. V.; Skakun, V. S.; Sosnin, E. A.; Suslov, A. I.; Tarasenko, V. F.; Schitz, D. V.

2008-07-01

The spectral and energy characteristics of multiband barrier-discharge coaxial KrBr excilamps are studied experimentally at pressures from a few tens of Torr to 0.4 atm. It is shown that an increase in the Br2 concentration reduces the emission intensity of KrBr* molecules with respect to the emission intensity of Br2* molecules and reduces the total emission power of the excilamp. This can be explained by the nonradiative decay of exciplex KrBr* molecules caused by their quenching by molecular bromine. The emission power and efficiency in the Kr:Br2 = 400:1 mixture at a pressure of ≈230 Torr and a discharge gap of 8.5 mm were 4.8 W and 2.4%, respectively.

Orbital transfer of large space structures with nuclear electric rockets

NASA Technical Reports Server (NTRS)

Silva, T. H.; Byers, D. C.

1980-01-01

This paper discusses the potential application of electric propulsion for orbit transfer of a large spacecraft structure from low earth orbit to geosynchronous altitude in a deployed configuration. The electric power was provided by the spacecraft nuclear reactor space power system on a shared basis during transfer operations. Factors considered with respect to system effectiveness included nuclear power source sizing, electric propulsion thruster concept, spacecraft deployment constraints, and orbital operations and safety. It is shown that the favorable total impulse capability inherent in electric propulsion provides a potential economic advantage over chemical propulsion orbit transfer vehicles by reducing the number of Space Shuttle flights in ground-to-orbit transportation requirements.

A power-efficient analog integrated circuit for amplification and detection of neural signals.

PubMed

Borghi, T; Bonfanti, A; Gusmeroli, R; Zambra, G; Spinelli, A S

2008-01-01

We present a neural amplifier that optimizes the trade-off between power consumption and noise performance down to the best so far reported. In the perspective of realizing a fully autonomous implantable system we also address the problem of spike detection by using a new simple algorithm and we discuss the implementation with analog integrated circuits. Implemented in 0.35-microm CMOS technology and with total current consumption of about 20 microA, the whole circuit occupies an area of 0.18 mm(2). Reduced power consumption and small area make it suited to be used in chronic multichannel recording systems for neural prosthetics and neuroscience experiments.

A Low-Power Instruction Issue Queue for Microprocessors

NASA Astrophysics Data System (ADS)

Watanabe, Shingo; Chiyonobu, Akihiro; Sato, Toshinori

Instruction issue queue is a key component which extracts instruction level parallelism (ILP) in modern out-of-order microprocessors. In order to exploit ILP for improving processor performance, instruction queue size should be increased. However, it is difficult to increase the size, since instruction queue is implemented by a content addressable memory (CAM) whose power and delay are much large. This paper introduces a low power and scalable instruction queue that replaces the CAM with a RAM. In this queue, instructions are explicitly woken up. Evaluation results show that the proposed instruction queue decreases processor performance by only 1.9% on average. Furthermore, the total energy consumption is reduced by 54% on average.

Impact of Radiation Hardness and Operating Temperatures of Silicon Carbide Electronics on Space Power System Mass

NASA Technical Reports Server (NTRS)

Juhasz, Albert J.; Tew, Roy C.; Schwarze, Gene E.

1998-01-01

The effect of silicon carbide (SiC) electronics operating temperatures on Power Management and Distribution (PMAD), or Power Conditioning (PC), subsystem radiator size and mass requirements was evaluated for three power output levels (100 kW(e) , 1 MW(e), and 10 MW(e)) for near term technology ( i.e. 1500 K turbine inlet temperature) Closed Cycle Gas Turbine (CCGT) power systems with a High Temperature Gas Reactor (HTGR) heat source. The study was conducted for assumed PC radiator temperatures ranging from 370 to 845 K and for three scenarios of electrical energy to heat conversion levels which needed to be rejected to space by means of the PC radiator. In addition, during part of the study the radiation hardness of the PC electronics was varied at a fixed separation distance to estimate its effect on the mass of the instrument rated reactor shadow shield. With both the PC radiator and the conical shadow shield representing major components of the overall power system the influence of the above on total power system mass was also determined. As expected, results show that the greatest actual mass savings achieved by the use of SiC electronics occur with high capacity power systems. Moreover, raising the PC radiator temperature above 600 K yields only small additional system mass savings. The effect of increased radiation hardness on total system mass is to reduce system mass by virtue of lowering the shield mass.

Antioxidant activity of commonly consumed cereals, millets, pulses and legumes in India.

PubMed

Sreeramulu, D; Reddy, C Vijaya Kumar; Raghunath, M

2009-02-01

Plant foods are important due to their antioxidant activity (AOA) attributed to the phenolics which are known to protect organisms against harmful effects of oxygen radicals. However, information on antioxidant activity of Indian plant foods is scanty. Therefore, the present study evaluated the AOA of cereals, millets, pulses and legumes, commonly consumed in India and assessed the relationship with their total phenolic content (TPC). AOA was assessed by DPPH (2,2-Diphenyl-1-picryl hydrazyl) radical scavenging assay, ferric reducing antioxidant power (FRAP) assay and reducing power. DPPH scavenging activity ranged from 0.24 and 1.73 mg/g, whereas FRAP ranged from 16.21 to 471.71 micromoles/g. Finger millet (Eleusine cora cana) and Rajmah (Phaseolus vulgaris) had the highest FRAP 471.71, 372.76 and DPPH scavenging activity 1.73, 1.07. Similar trends were observed with reducing power. Among cereals and legumes, Finger millet (Ragi) and black gram dhal (Phaseolus mungo Roxb) had the highest TPC, the values being 373 and 418 mg/100 g respectively, while rice (Oryza sativa) and green gram dhal (Phaseolus aureus Roxb) showed the least (47.6 and 62.4 mg/100 g). In the present study, FRAP (r = 0.91) and reducing power (r = 0.90) showed significant correlation with TPC in cereals and millets, but not in pulses and legumes. The results suggest that TPC contributes significantly to the AOA of Indian cereals and millets.

Morphological and biochemical changes in Azadirachta indica from coal combustion fly ash dumping site from a thermal power plant in Delhi, India.

PubMed

Qadir, Sami Ullah; Raja, Vaseem; Siddiqui, Weqar A

2016-07-01

The foliar and biochemical traits of Azadirachta indica A. Juss from fly ash (FA) dumping site in Badarpur thermal power plant (BTPP) New Delhi, India was studied. Three different experimental sites were selected at different distances from the thermal power plant. Ambient suspended particulate matter (SPM) and plant responses such as leaf pigments (chlorophyll a, chlorophyll b, and carotenoids), total chlorophyll, net photosynthetic rate, stomatal index (SI), stomatal conductance (SC), intercellular carbon dioxide concentration [CO2]i, net photosynthetic rate (NPR), nitrogen, nitrate, nitrate reductase activity, proline, protein, reducing sugar and sulphur content were measured. Considerable reduction in pigments (chlorophyll a, chlorophyll b and carotenoids), and total chlorophyll was observed at fly ash dumping site. Fly ash stress revealed the inhibitory effect on Nitrate reductase activity (NRA), Nitrate, soluble protein, and reducing sugar content, whereas stimulatory effect was found for the stomatal index, nitrogen, proline, antioxidants and sulphur content in the leaves. Under fly ash stress, stomatal conductance was low, leading to declining in photosynthetic rate and increase in the internal CO2 concentration of leaf. Single leaf area (SLA), leaf length and leaf width also showed a declining trend from control to the polluted site. Antioxidant enzymes increased in leaves reflecting stress and extenuation of reactive oxygen species (ROS). Copyright © 2016 Elsevier Inc. All rights reserved.

Low-complexity peak-to-average power ratio reduction scheme for flip-orthogonal frequency division multiplexing visible light communication system based on μ-law mapping

NASA Astrophysics Data System (ADS)

Wang, Jianping; Zhang, Peiran; Lu, Huimin; Feng, LiFang

2017-06-01

An orthogonal frequency division multiplexing (OFDM) technique called flipped OFDM (flip-OFDM) is apposite for a visible light communication system that needs the transmitted signal to be real and positive. Flip-OFDM uses two consecutive OFDM subframes to transmit the positive and negative parts of the signal. However, peak-to-average power ratio (PAPR) for flip-OFDM is increased tremendously due to the low value of total average power that arises from many zero values in both the positive and flipped frames. We first analyze the performance of flip-OFDM and perform a comparison with the conventional DC-biased OFDM (DCO-OFDM); then we propose a flip-OFDM scheme combined with μ-law mapping to reduce the high PAPR. The simulation results show that the PAPR of the system is reduced about 17.2 and 5.9 dB when compared with the normal flip-OFDM and DCO-OFDM signals, respectively.

Antioxidant capacity of cornelian cherry (Cornus mas L.) - comparison between permanganate reducing antioxidant capacity and other antioxidant methods.

PubMed

Popović, Boris M; Stajner, Dubravka; Slavko, Kevrešan; Sandra, Bijelić

2012-09-15

Ethanol extracts (80% in water) of 10 cornelian cherry (Cornus mas L.) genotypes were studied for antioxidant properties, using methods including DPPH(), ()NO, O(2)(-) and ()OH antiradical powers, FRAP, total phenolic and anthocyanin content (TPC and ACC) and also one relatively new, permanganate method (permanganate reducing antioxidant capacity-PRAC). Lipid peroxidation (LP) was also determined as an indicator of oxidative stress. The data from different procedures were compared and analysed by multivariate techniques (correlation matrix calculation and principal component analysis (PCA)). Significant positive correlations were obtained between TPC, ACC and DPPH(), ()NO, O(2)(-), and ()OH antiradical powers, and also between PRAC and TPC, ACC and FRAP. PCA found two major clusters of cornelian cherry, based on antiradical power, FRAP and PRAC and also on chemical composition. Chemometric evaluation showed close interdependence between PRAC method and FRAP and ACC. There was a huge variation between C. mas genotypes in terms of antioxidant activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

An Analysis of Costs and Health Co-Benefits for a U.S. Power Plant Carbon Standard

PubMed Central

Buonocore, Jonathan J.; Lambert, Kathleen F.; Burtraw, Dallas; Sekar, Samantha; Driscoll, Charles T.

2016-01-01

Reducing carbon dioxide (CO2) emissions from power plants can have important “co-benefits” for public health by reducing emissions of air pollutants. Here, we examine the costs and health co-benefits, in monetary terms, for a policy that resembles the U.S. Environmental Protection Agency’s Clean Power Plan. We then examine the spatial distribution of the co-benefits and costs, and the implications of a range of cost assumptions in the implementation year of 2020. Nationwide, the total health co-benefits were $29 billion 2010 USD (95% CI: $2.3 to $68 billion), and net co-benefits under our central cost case were $12 billion (95% CI: -$15 billion to $51 billion). Net co-benefits for this case in the implementation year were positive in 10 of the 14 regions studied. The results for our central case suggest that all but one region should experience positive net benefits within 5 years after implementation. PMID:27270222

An Analysis of Costs and Health Co-Benefits for a U.S. Power Plant Carbon Standard.

PubMed

Buonocore, Jonathan J; Lambert, Kathleen F; Burtraw, Dallas; Sekar, Samantha; Driscoll, Charles T

2016-01-01

Reducing carbon dioxide (CO2) emissions from power plants can have important "co-benefits" for public health by reducing emissions of air pollutants. Here, we examine the costs and health co-benefits, in monetary terms, for a policy that resembles the U.S. Environmental Protection Agency's Clean Power Plan. We then examine the spatial distribution of the co-benefits and costs, and the implications of a range of cost assumptions in the implementation year of 2020. Nationwide, the total health co-benefits were $29 billion 2010 USD (95% CI: $2.3 to $68 billion), and net co-benefits under our central cost case were $12 billion (95% CI: -$15 billion to $51 billion). Net co-benefits for this case in the implementation year were positive in 10 of the 14 regions studied. The results for our central case suggest that all but one region should experience positive net benefits within 5 years after implementation.

A 20,000-Kilowatt Nuclear Turboelectric Power Supply for Manned Space Vehicles

NASA Technical Reports Server (NTRS)

English, Robert E.; Slone, Henry O.; Bernatowicz, Daniel T.; Davison, Elmer H.; Lieblein, Seymour

1959-01-01

A conceptual design of a nuclear turboelectric powerplant, producing 20,000 kilowatts of power suitable for manned space vehicles is presented. The study indicates that the radiator necessary for rejecting cycle waste heat is the dominant weight, and emphasis is placed on the selection of cycle operating conditions in order to reduce this weight. A thermodynamic cycle using sodium vapor as the working fluid and operating at a turbine-inlet temperature of 2500 R was selected. The total powerplant weight was calculated to be approximately 6 pounds per kilowatt. The radiator contributes approximately 2.1 pounds per kilowatt to the total weight and the reactor and reactor shield contribute approximately 0.24 and 1.2 pounds per kilowatt, respectively. The generator, turbine, and piping add significantly to the total weight (between 0.5 and 0.6 lb/kw), but the heat exchanger, pumps, and so on are less important. Several important research areas associated with the development of a reliable nuclear turboelectric powerplant of the type analyzed are discussed.

Future CO2 emissions and electricity generation from proposed coal-fired power plants in India

NASA Astrophysics Data System (ADS)

Fofrich, R.; Shearer, C.; Davis, S. J.

2017-12-01

India represents a critical unknown in global projections of future CO2 emissions due to its growing population, industrializing economy, and large coal reserves. In this study, we assess existing and proposed construction of coal-fired power plants in India and evaluate their implications for future energy production and emissions in the country. In 2016, India had 369 coal-fired power plants under development totaling 243 gigawatts (GW) of generating capacity. These coal-fired power plants would increase India's coal-fired generating capacity by 123% and would exceed India's projected electricity demand. Therefore, India's current proposals for new coal-fired power plants would be forced to retire early or operate at very low capacity factors and/or would prevent India from meeting its goal of producing at least 40% of its power from renewable sources by 2030. In addition, future emissions from proposed coal-fired power plants would exceed India's climate commitment to reduce its 2005 emissions intensity 33% - 35% by 2030.

Polyphenolic content and antioxidant activity of some wild Saudi Arabian Asteraceae plants.

PubMed

Shahat, Abdelaaty A; Ibrahim, Abeer Y; Elsaid, Mansour S

2014-07-01

To study the antioxidant properties of crude extract of different Asteraceae plants. The antioxidant properties of six extracts were evaluated using different antioxidant tests, including free radical scavenging, reducing power, metal chelation, superoxide anion radical scavenging, total antioxidant capacity and inhibition of lipid peroxidation activities. Picris cyanocarpa (P. cyanocarpa) and Anthemis deserti (A. deserti) had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger while Achillia fragrantissima (A. fragrantissima) and Artemissia monosperma (A. monosperma) were the most efficient as ion chelator (100% at 100, 200 and 400 μg/mL) A. fragrantissima and Rhantarium appoposum (R. appoposum) showed 100% inhibition on peroxidation of linoleic acid emulsion at 200 and 400 μg/mL, while butylatedhydroxy toluene and ascorbic acid showed 100 and 95% inhibition percentage at 400 μg/mL, respectively. Those various antioxidant activities were compared to standard antioxidants such as butylated hydroxyl toluene and ascorbic acid. In most tests P. cyanocarpa and A. deserti had powerful antioxidant properties as radical scavenger, reducing agent and superoxide anion radical scavenger. Copyright © 2014 Hainan Medical College. Published by Elsevier B.V. All rights reserved.

Development of a valved non-lubricated linear compressor for compact 2K Gifford-McMahon cryocoolers

NASA Astrophysics Data System (ADS)

Hiratsuka, Y.; Bao, Q.; Xu, M.

2017-02-01

Recently, a new, compact Gifford-McMahon (GM) cryocooler for cooling superconducting single photon detectors (SSPD) has been developed and reported by Sumitomo Heavy Industries, Ltd. (SHI) [1]. It was reported that National Institute of Information and Communications Technology (NICT) developed a multi-channel SSPD system in which two or more channels were mounted on a GM cryocooler, and achieved a world-top-class performance [2]. However, the applications of such SSPD system were restricted due to its relatively large size and power consumption compared with a semiconductor system. Owing to the development of an SSPD system with a portable cryocooler system which can be installed in a vehicle, it is possible to apply such system to the optical communication of AdHoc [3], and to flexibly construct a large capacity optical line in a time of disaster. For such system, the size and power consumption reduction becomes indispensable. The objective is to reduce the total height of the expander by 33% relative to the existing RDK-101 GM expander and to reduce the total volume of the compressor unit by 50% relative to the existing CNA-11 compressor. In addition, considering the targeted cooling application, we set the design temperature targets of the first and the second stages to 1 W and 20 mW of heat load at 60 K and 2.3 K, respectively. In 2015, Hiratsuka reported that a new valved non-lubricated compressor was developed for a 2K GM cryocooler [4]. The cooling performance of a 2K GM expander operated by an experimental unit of the linear compressor was measured, and preliminary experiments were conducted. No-load temperature was 2.19 K, with 1 W and 14 mW heat load, the temperature was 48 K at the first stage and 2.3 K at the second stage, with an input power of about 1.2 kW. After that, the compressor efficiency has been improved by reducing losses, and the compressor input power has been reduced by 25%. The detailed experimental results are discussed in this paper.

Life Cycle Assessment of Coal-fired Power Production

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

Spath, P. L.; Mann, M. K.; Kerr, D. R.

1999-09-01

Coal has the largest share of utility power generation in the US, accounting for approximately 56% of all utility-produced electricity (US DOE, 1998). Therefore, understanding the environmental implications of producing electricity from coal is an important component of any plan to reduce total emissions and resource consumption. A life cycle assessment (LCA) on the production of electricity from coal was performed in order to examine the environmental aspects of current and future pulverized coal boiler systems. Three systems were examined: (1) a plant that represents the average emissions and efficiency of currently operating coal-fired power plants in the US (thismore » tells us about the status quo), (2) a new coal-fired power plant that meets the New Source Performance Standards (NSPS), and (3) a highly advanced coal-fired power plant utilizing a low emission boiler system (LEBS).« less

CO2 Mitigation Measures of Power Sector and Its Integrated Optimization in China

PubMed Central

Dai, Pan; Chen, Guang; Zhou, Hao; Su, Meirong; Bao, Haixia

2012-01-01

Power sector is responsible for about 40% of the total CO2 emissions in the world and plays a leading role in climate change mitigation. In this study, measures that lower CO2 emissions from the supply side, demand side, and power grid are discussed, based on which, an integrated optimization model of CO2 mitigation (IOCM) is proposed. Virtual energy, referring to energy saving capacity in both demand side and the power grid, together with conventional energy in supply side, is unified planning for IOCM. Consequently, the optimal plan of energy distribution, considering both economic benefits and mitigation benefits, is figured out through the application of IOCM. The results indicate that development of demand side management (DSM) and smart grid can make great contributions to CO2 mitigation of power sector in China by reducing the CO2 emissions by 10.02% and 12.59%, respectively, in 2015, and in 2020. PMID:23213305

Electrocortical effects of MDMA are potentiated by acoustic stimulation in rats.

PubMed

Iannone, Michelangelo; Bulotta, Stefania; Paolino, Donatella; Zito, Maria Cristina; Gratteri, Santo; Costanzo, Francesco S; Rotiroti, Domenicantonio

2006-02-16

3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is known for its toxicological, psychopathological and abuse potential. Some environmental conditions, e.g. acoustic stimulation typical of the "rave scene" can influence the toxicity of this drug. We investigated the effects of low doses of MDMA in vivo using Wistar rats in the absence of acoustic stimulation (white noise; 95 Db) demonstrating that ecstasy is able to induce a significant activation (reduction of Electrocortical total power) of the telencephalic cortex that spontaneously reverts in the absence of sensorial stimuli, whereas it persists for several days if, in addition to MDMA, the animals are exposed to acoustic stimulation. Our data demonstrate that low doses of MDMA are able to reduce electrocortical total power, and that this effect is potentiated by sensorial stimuli commonly present in certain environments, such as rave parties.

Climate change impacts on thermoelectric-power generation in the United States

NASA Astrophysics Data System (ADS)

Liu, L.

2015-12-01

Thermoelectric-power generation accounts for more than 70% of the total electricity generation in the United States, which requires large amounts of water for cooling purposes. Water withdrawals for thermoelectric-power generation accounted for 45% of total water use in the United States in 2010. Across the country, water demand from power plants is increasing due to pressures from growing populations and other needs, and is straining existing water resources. Moreover, temperature exceedance in receiving waters has increasingly caused power plants shut downs across parts of the country. Thermoelectric power is vulnerable to climate change owing to the combined effects of lower summer river flows and higher receiving water temperatures. In addition, the efficiency of production is reduced as air temperature rises, which propagates to more unfulfilled power demand during peak seasons. Therefore, a holistic modeling framework of water-energy-climate for the contiguous U.S. is presented here to quantify thermal output from power plants and estimate water use and energy production fluctuations due to ambient climate as well as environmental regulations. The model is calibrated on a plant-by-plant basis for year 2010 and 2011 using the available power plant inventory from the Energy Information Administration (EIA). Simulations were carried out for years 2012 and 2013, and results show moderate improvements in capturing thermal output variabilities after calibration. Future power plant operations under scenarios featuring different climate and regulatory settings were investigated. Results demonstrate the interplay among water, energy and climate, and that future changes in climate and socioeconomics significantly affect power plant operations, which may provide insights to climate change mitigation considerations and energy decisions.

Mercury emission and speciation of coal-fired power plants in China

NASA Astrophysics Data System (ADS)

Wang, S. X.; Zhang, L.; Li, G. H.; Wu, Y.; Hao, J. M.; Pirrone, N.; Sprovieri, F.; Ancora, M. P.

2010-02-01

Comprehensive field measurements are needed to understand the mercury emissions from Chinese power plants and to improve the accuracy of emission inventories. Characterization of mercury emissions and their behavior were measured in six typical coal-fired power plants in China. During the tests, the flue gas was sampled simultaneously at inlet and outlet of Selective Catalytic Reduction (SCR), electrostatic precipitators (ESP), and flue gas desulfurization (FGD) using the Ontario Hydro Method (OHM). The pulverized coal, bottom ash, fly ash and gypsum were also sampled in the field. Mercury concentrations in coal burned in the measured power plants ranged from 17 to 385 μg/kg. The mercury mass balances for the six power plants varied from 87 to 116% of the input coal mercury for the whole system. The total mercury concentrations in the flue gas from boilers were at the range of 1.92-27.15 μg/m3, which were significantly related to the mercury contents in burned coal. The mercury speciation in flue gas right after the boiler is influenced by the contents of halogen, mercury, and ash in the burned coal. The average mercury removal efficiencies of ESP, ESP plus wet FGD, and ESP plus dry FGD-FF systems were 24%, 73% and 66%, respectively, which were similar to the average removal efficiencies of pollution control device systems in other countries such as US, Japan and South Korea. The SCR system oxidized 16% elemental mercury and reduced about 32% of total mercury. Elemental mercury, accounting for 66-94% of total mercury, was the dominant species emitted to the atmosphere. The mercury emission factor was also calculated for each power plant.

Mercury emission and speciation of coal-fired power plants in China

NASA Astrophysics Data System (ADS)

Wang, S.; Zhang, L.; Li, G.; Wu, Y.; Hao, J.; Pirrone, N.; Sprovieri, F.; Ancora, M. P.

2009-11-01

Comprehensive field measurements are needed to understand the mercury emissions from Chinese power plants and to improve the accuracy of emission inventories. Characterization of mercury emissions and their behavior were measured in six typical coal-fired power plants in China. During the tests, the flue gas was sampled simultaneously at inlet and outlet of selective catalyst reduction (SCR), electrostatic precipitators (ESP), and flue gas desulfurization (FGD) using the Ontario Hydro Method (OHM). The pulverized coal, bottom ash, fly ash and gypsum were also sampled in the field. Mercury concentrations in coal burned in the measured power plants ranged from 17 to 385 μg/kg. The mercury mass balances for the six power plants varied from 87 to 116% of the input coal mercury for the whole system. The total mercury concentrations in the flue gas from boilers were at the range of 1.92-27.15 μg/m3, which were significantly related to the mercury contents in burned coal. The mercury speciation in flue gas right after the boiler is influenced by the contents of halogen, mercury, and ash in the burned coal. The average mercury removal efficiencies of ESP, ESP plus wet FGD, and ESP plus dry FGD-FF systems were 24%, 73% and 66%, respectively, which were similar to the average removal efficiencies of pollution control device systems in other countries such as US, Japan and South Korea. The SCR system oxidized 16% elemental mercury and reduced about 32% of total mercury. Elemental mercury, accounting for 66-94% of total mercury, was the dominant species emitted to the atmosphere. The mercury emission factor was also calculated for each power plant.

Development of novel high power-short time (HPST) microwave assisted commercial decontamination process for dried turmeric powder (Curcuma Longa L.).

PubMed

Behera, G; Sutar, P P; Aditya, S

2017-11-01

The commercially available dry turmeric powder at 10.34% d.b. moisture content was decontaminated using microwaves at high power density for short time. To avoid the loss of moisture from turmeric due to high microwave power, the drying kinetics were modelled and considered during optimization of microwave decontamination process. The effect of microwave power density (10, 33.5 and 57 W g -1 ), exposure time (10, 20 and 30 s) and thickness of turmeric layer (1, 2 and 3 mm) on total plate, total yeast and mold (YMC) counts, color change (∆E), average final temperature of the product (T af ), water activity (a w ), Page model rate constant (k) and total moisture loss (ML) was studied. The perturbation analysis was carried out for all variables. It was found that to achieve more than one log reduction in yeast and mold count, a substantial reduction in moisture content takes place leading to the reduced output. The microwave power density significantly affected the YMC, T af and a w of turmeric powder. But the thickness of sample and microwave exposure time showed effect only on T af , a w and ML. The colour of turmeric and Page model rate constant were not significantly changed during the process as anticipated. The numerical optimization was done at 57.00 W g -1 power density, 1.64 mm thickness of sample layer and 30 s exposure time. It resulted into 1.6 × 10 7 CFU g -1 YMC, 82.71 °C T af , 0.383 a w and 8.41% (d.b.) final moisture content.

An inter-lighting interference cancellation scheme for MISO-VLC systems

NASA Astrophysics Data System (ADS)

Kim, Kyuntak; Lee, Kyujin; Lee, Kyesan

2017-08-01

In this paper, we propose an inter-lighting interference cancellation (ILIC) scheme to reduce the interference between adjacent light-emitting diodes (LEDs) and enhance the transmission capacity of multiple-input-single-output (MISO)-visible light communication (VLC) systems. In indoor environments, multiple LEDs have normally been used as lighting sources, allowing the design of MISO-VLC systems. To enhance the transmission capacity, different data should be simultaneously transmitted from each LED; however, that can lead to interference between adjacent LEDs. In that case, relatively low-received power signals are subjected to large interference because wireless optical systems generally use intensity modulation and direct detection. Thus, only the signal with the highest received power can be detected, while the other received signals cannot be detected. To solve this problem, we propose the ILIC scheme for MISO-VLC systems. The proposed scheme preferentially detects the highest received power signal, and this signal is referred as interference signal by an interference component generator. Then, relatively low-received power signal can be detected by cancelling the interference signal from the total received signals. Therefore, the performance of the proposed scheme can improve the total average bit error rate and throughput of a MISO-VLC system.

Analysis of the effects of boundary-layer control in the take-off and power-off landing performance characteristics of a liaison type of airplane

NASA Technical Reports Server (NTRS)

Horton, Elmer A; Loftin, Laurence K; Racisz, Stanley F; Quinn, John

1951-01-01

A performance analysis has been made to determine whether boundary-layer control by suction might reduce the minimum take-off and landing distances of a four-place or five-place airplane or a liaison type of airplane below those obtainable with conventional high-lift devices. The airplane was assumed to have a cruise duration of 5 hours at 60-percent power and to be operating from airstrips having a ground friction coefficient of 0.2 or a combined ground and braking coefficient of 0.4. The payload was fixed at 1500 pounds, the wing span was varied from 25 to 100 feet, the aspect ratio was varied from 5 to 15, and the power was varied from 300 to 1300 horsepower. Maximum lift coefficients of 5.0 and 2.8 were assumed for the airplanes with and without boundary-layer-control --equipment weight was included. The effects of the boundary-layer control on total take-off distance, total power-off landing distance, landing and take-off ground run, stalling speed, sinking speed, and gliding speed were determined.

Vernonia condensata Baker (Asteraceae): A Promising Source of Antioxidants

PubMed Central

da Silva, Jucélia Barbosa; Temponi, Vanessa dos Santos; Gasparetto, Carolina Miranda; Fabri, Rodrigo Luiz; Aragão, Danielle Maria de Oliveira; Pinto, Nícolas de Castro Campos; Ribeiro, Antônia; Scio, Elita; Del-Vechio-Vieira, Glauciemar; de Sousa, Orlando Vieira

2013-01-01

The present study evaluated the antioxidant potential of Vernonia condensata Baker (Asteraceae). Dried and powdered leaves were exhaustively extracted with ethanol by static maceration followed by partition to obtain the hexane, dichloromethane, ethyl acetate, and butanol fractions. Total phenols and flavonoids contents were determined through spectrophotometry and flavonoids were identified by HPLC-DAD system. The antioxidant activity was assessed by DPPH radical scavenging activity, TLC-bioautography, reducing power of Fe+3, phosphomolybdenum, and TBA assays. The total phenolic content and total flavonoids ranged from 0.19 to 23.11 g/100 g and from 0.13 to 4.10 g/100 g, respectively. The flavonoids apigenin and luteolin were identified in the ethyl acetate fraction. The IC50 of DPPH assay varied from 4.28 to 75.10 µg/mL and TLC-bioautography detected the antioxidant compounds. The reducing power of Fe+3 was 19.98 to 336.48 μg/mL, while the reaction with phosphomolybdenum ranged from 13.54% to 32.63% and 56.02% to 135.00% considering ascorbic acid and rutin as reference, respectively. At 30 mg/mL, the ethanolic extract and fractions revealed significant effect against lipid peroxidation. All these data sustain that V. condensata is an important and promising source of bioactive substances with antioxidant activity. PMID:24489987

Bioactive screening and in vitro antioxidant assessment of Nauclea latifolia leaf decoction

NASA Astrophysics Data System (ADS)

Iheagwam, Franklyn Nonso; Nsedu, Emmanuel Israel; Kayode, Kazeem Oyindamola; Emiloju, Opeyemi Christianah; Ogunlana, Olubanke Olujoke; Chinedu, Shalom Nwodo

2018-04-01

The phytochemical constituents and antioxidant properties of Nauclea latifolia leaf decoction were investigated. Dried leaves were extracted in ethanol. Qualitative and quantitative phytochemical analysis was determined spectrometrically. The antioxidant activities were examined in vitro using 2,2-diphenyl-1-picrylhydrazyl radical, total antioxidant capacity and ferric reducing antioxidant power assays. Phytochemical screening confirmed the presence of flavonoids, alkaloids, anthocyanins, betacyanins, phenols, saponins, terpenoids, cardiac glycosides and quinones. The total lycopene, β-carotene, phenolics, flavonoid and alkaloid content were found to be 0.038 ± 0.01 mg CAE/g, 0.120 ± 0.04 mg CAE/g, 58.08 ± 0.58 mg GAE/g, 10.75 ± 0.17 mg RE/g and 0.32 ± 0.08% respectively. N. latifolia ethanol leaf extract demonstrated effective antioxidant activity against 2,2-diphenyl-1-picrylhydrazyl with an IC50 of 2.58 ± 0.08 mg/mL compared to 0.86 ± 0.02 mg/mL and < 0.01 ± 0.01 mg/mL for butylated hydroxytoluene and ascorbic acid respectively. Total antioxidant capacity and ferric reducing antioxidant power of the extract were 73.81 ± 2.27 and 1314.45 ± 197.64 mg AAE/g respectively. Excellent positive correlations between the phenolic content and antioxidant activities of the extract were observed. The leaf of N. latifolia is of therapeutic value and may be exploited for its rich antioxidant components.

C-fiber-related EEG-oscillations induced by laser radiant heat stimulation of capsaicin-treated skin

PubMed Central

Domnick, Claudia; Hauck, Michael; Casey, Kenneth L; Engel, Andreas K; Lorenz, Jürgen

2009-01-01

Nociceptive input reaches the brain via two different types of nerve fibers, moderately fast A-delta and slowly conducting C-fibers, respectively. To explore their distinct roles in normal and inflammatory pain we used laser stimulation of normal and capsaicin treated skin at proximal and distal arm sites in combination with time frequency transformation of electroencephalography (EEG) data. Comparison of phase-locked (evoked) and non-phase-locked (total) EEG to laser stimuli revealed three significant pain-related oscillatory responses. First, an evoked response in the delta-theta band, mediated by A-fibers, was reduced by topical capsaicin treatment. Second, a decrease of total power in the alpha-to-gamma band reflected both an A- and C-nociceptor-mediated response with only the latter being reduced by capsaicin treatment. Finally, an enhancement of total power in the upper beta band was mediated exclusively by C-nociceptors and appeared strongly augmented by capsaicin treatment. These findings suggest that phase-locking of brain activity to stimulus onset is a critical feature of A-delta nociceptive input, allowing rapid orientation to salient and potentially threatening events. In contrast, the subsequent C-nociceptive input exhibits clearly less phase coupling to the stimulus. It may primarily signal the tissue status allowing more long-term behavioral adaptations during ongoing inflammatory events that accompany tissue damage. PMID:21197293

H2 arcjet performance mapping program

NASA Astrophysics Data System (ADS)

1992-01-01

Work performed during the period of Mar. 1991 to Jan. 1992 is reviewed. High power H2 arcjets are being considered for electric powered orbit transfer vehicles (EOTV). Mission analyses indicate that the overall arcjet thrust efficiency is very important since increasing the efficiency increases the thrust, and thereby reduces the total trip time for the same power. For example, increasing the thrust efficiency at the same specific impulse from 30 to 40 percent will reduce the trip time by 25 percent. For a 200 day mission, this equates to 50 days, which results in lower ground costs and less time during which the payload is dormant. Arcjet performance levels of 1200 seconds specific impulse (lsp) at 35 to 40 percent efficiency with lifetimes over 1000 hours are needed to support EOTV missions. Because of the potential very high efficiency levels, the objective of this program was to evaluate the ability of a scaled Giannini-style thruster to achieve the performance levels while operating at a reduced nominal power of 10 kW. To meet this objective, a review of past literature was conducted; scaling relationships were developed and applied to establish critical dimensions; a development thruster was designed with the aid of the plasma analysis model KARNAC and finite element thermal modeling; test hardware was fabricated; and a series of performance tests were conducted in RRC's Cell 11 vacuum chamber with its null-balance thrust stand.

Ultrathin zoom telescopic objective.

PubMed

Li, Lei; Wang, Di; Liu, Chao; Wang, Qiong-Hua

2016-08-08

We report an ultrathin zoom telescopic objective that can achieve continuous zoom change and has reduced compact volume. The objective consists of an annular folded lens and three electrowetting liquid lenses. The annular folded lens undertakes the main part of the focal power of the lens system. Due to a multiple-fold design, the optical path is folded in a lens with the thickness of ~1.98mm. The electrowetting liquid lenses constitute a zoom part. Based on the proposed objective, an ultrathin zoom telescopic camera is demonstrated. We analyze the properties of the proposed objective. The aperture of the proposed objective is ~15mm. The total length of the system is ~18mm with a tunable focal length ~48mm to ~65mm. Compared with the conventional zoom telescopic objective, the total length has been largely reduced.

Antioxidant activity of spice extracts in a liposome system and in cooked pork patties and the possible mode of action.

PubMed

Kong, Baohua; Zhang, Huiyun; Xiong, Youling L

2010-08-01

Three experiments were conducted to assess the antioxidant efficacy of spice extracts in cooked meat. In experiment 1, antioxidant activity of 13 common spice extracts was screened in a liposome system. Six of the extracts (clove, rosemary, cassia bark, liquorice, nutmeg, and round cardamom), identified to have the greatest total phenolic contents, were strongly inhibitory of TBARS formation. In experiment 2, 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, ferric-reducing power, and metal chelation of these six spice extracts were evaluated. Clove exhibited the greatest reducing power, and all had strong DPPH scavenging activity. In experiment 3, clove, rosemary, and cassia bark extracts were further tested for in situ antioxidant efficacy. Cooked pork patties containing these spice extracts had markedly reduced TBARS formation and off-flavour scores but a more stable red colour, during storage. The results demonstrated strong potential of spice extracts as natural antioxidants in cooked pork products. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

Status of Technological Advancements for Reducing Aircraft Gas Turbine Engine Pollutant Emissions

NASA Technical Reports Server (NTRS)

Rudey, R. A.

1975-01-01

Combustor test rig results indicate that substantial reductions from current emission levels of carbon monoxide (CO), total unburned hydrocarbons (THC), oxides of nitrogen (NOx), and smoke are achievable by employing varying degrees of technological advancements in combustion systems. Minor to moderate modifications to existing conventional combustors produced significant reductions in CO and THC emissions at engine low power (idle/taxi) operating conditions but did not effectively reduce NOx at engine full power (takeoff) operating conditions. Staged combusiton techniques were needed to simultaneously reduce the levels of all the emissions over the entire engine operating range (from idle to takeoff). Emission levels that approached or were below the requirements of the 1979 EPA standards were achieved with the staged combustion systems and in some cases with the minor to moderate modifications to existing conventional combustion systems. Results from research programs indicate that an entire new generation of combustor technology with extremely low emission levels may be possible in the future.

The right place for the right job in the photovoltaic life cycle.

PubMed

Kawajiri, Kotaro; Genchi, Yutaka

2012-07-03

The potential for photovoltaic power generation (PV) to reduce primary energy consumption (PEC) and CO(2) emissions depends on the physical locations of each stage of its life cycle. When stages are optimally located, CO(2) emissions are reduced nearly ten times as much as when each stage is located in the country having the largest current market share. The usage stage contributes the most to reducing CO(2) emissions and PEC, and total CO(2) emissions actually increase when PV is installed in countries having small CO(2) emissions from electricity generation. Global maps of CO(2) reduction potential indicate that Botswana and Gobi in Mongolia are the optimal locations to install PV due to favorable conditions for PV power generation and high CO(2) emissions from current electricity generation. However, the small electricity demand in those countries limits the contribution to global CO(2) reduction. The type of PVs has a small but significant effect on life cycle PEC and CO(2) emissions.

Flight investigation of the effect of tail boom strakes on helicopter directional control

NASA Technical Reports Server (NTRS)

Kelly, Henry L.; Crowell, Cynthia A.; Yenni, Kenneth R.; Lance, Michael B.

1993-01-01

A joint U.S. Army/NASA flight investigation was conducted utilizing a single-rotor helicopter to determine the effectiveness of horizontally mounted tail boom strakes on directional controllability and tail rotor power during low-speed, crosswind operating conditions. Three configurations were investigated: (1) baseline (strakes off), (2) single strake (strake at upper shoulder on port side of boom), and (3) double strake (upper strake plus a lower strake on same side of boom). The strakes were employed as a means to separate airflow over the tail boom and change fuselage yawing moments in a direction to improve the yaw control margin and reduce tail rotor power. Crosswind data were obtained in 5-knot increments of airspeed from 0 to 35 knots and in 30 deg increments of wind azimuth from 0 deg to 330 deg. At the most critical wind azimuth and airspeed in terms of tail rotor power, the strakes improved the pedal margin by 6 percent of total travel and reduced tail rotor power required by 17 percent. The increase in yaw control and reduction in tail rotor power offered by the strakes can expand the helicopter operating envelope in terms of gross weight and altitude capability. The strakes did not affect the flying qualities of the vehicle at airspeeds between 35 and 100 knots.

Design, Control, and Modeling of a New Voltage Source Converter for HVDC System

NASA Astrophysics Data System (ADS)

Mohan, Madhan; Singh, Bhim; Ketan Panigrahi, Bijaya

2013-05-01

Abstract: A New Voltage Source Converter (VSC) based on neutral clamped three-level circuit is proposed for High Voltage DC (HVDC) system. The proposed VSC is designed in a multipulse configuration. The converter is operated by Fundamental Frequency Switching (FFS). A new control method is developed for achieving all the necessary control aspects of HVDC system such as independent real and reactive power control, bidirectional real and reactive power control. The basic of the control method is varying the pulse width and by keeping the dc link voltage constant. The steady state and dynamic performances of HVDC system interconnecting two different frequencies network are demonstrated for active and reactive power control. Total number of transformers used in this system are reduced to half in comparison with the two-level VSCs for both active and reactive power control. The performance of the HVDC system is improved in terms of reduced harmonics level even at fundamental frequency switching. The harmonic performance of the designed converter is also studied for different value of the dead angle (β), and the optimized range of the dead angle is achieved for varying reactive power requirement. Simulation results are presented for the designed three level multipulse voltage source converters with the proposed control algorithm.

Design of an Input-Parallel Output-Parallel LLC Resonant DC-DC Converter System for DC Microgrids

NASA Astrophysics Data System (ADS)

Juan, Y. L.; Chen, T. R.; Chang, H. M.; Wei, S. E.

2017-11-01

Compared with the centralized power system, the distributed modularized power system is composed of several power modules with lower power capacity to provide a totally enough power capacity for the load demand. Therefore, the current stress of the power components in each module can then be reduced, and the flexibility of system setup is also enhanced. However, the parallel-connected power modules in the conventional system are usually controlled to equally share the power flow which would result in lower efficiency in low loading condition. In this study, a modular power conversion system for DC micro grid is developed with 48 V dc low voltage input and 380 V dc high voltage output. However, in the developed system control strategy, the numbers of power modules enabled to share the power flow is decided according to the output power at lower load demand. Finally, three 350 W power modules are constructed and parallel-connected to setup a modular power conversion system. From the experimental results, compared with the conventional system, the efficiency of the developed power system in the light loading condition is greatly improved. The modularized design of the power system can also decrease the power loss ratio to the system capacity.

Creating Brain Lesions by Low Intensity Focused Ultrasound with Microbubbles: A Rat Study at Half MHz

PubMed Central

Huang, Yuexi; Vykhodtseva, Natalia I.; Hynynen, Kullervo

2014-01-01

Low intensity focused ultrasound was applied with microbubbles (Definity, 0.02 mL/kg) to produce brain lesions in 50 rats at 558 kHz. Burst sonications (burst length: 10 ms; pulse repetition frequency: 1 Hz; total exposure: 5 min; acoustic powers: 0.47-1.3W) generated ischemic or hemorrhagic lesions at the focal volume revealed by both MR imaging and histology. Shorter burst (2 ms) or shorter sonication time (1 min) reduced the probability of lesion production. Longer pulses (200ms, 500ms and continuous wave) caused significant near-field damages. Using microbubbles with focused ultrasound significantly reduced the acoustic power levels, therefore avoided skull heating issues and potentially can extend the treatable volume of transcranial focused ultrasound to the brain tissues close to the skull. PMID:23743099

Armillaria mellea: phenolic content, in vitro antioxidant and antihyperglycemic effects.

PubMed

Zavastin, Daniela Elena; Mircea, Cornelia; Aprotosoaie, Ana Clara; Gherman, Simona; Hancianu, Monica; Miron, Anca

2015-01-01

Armillaria mellea, known as honey mushroom, has been used both as food and medicine. In this work, the ethanolic and hydromethanolic extracts from Armillaria mellea fruiting bodies were investigated for their phenolic content, antioxidant and antihyperglycemic effects (in vitro studies). The total phenolics were quantified using Folin-Ciocalteu assay. The antioxidant activity was evaluated by testing the free radical scavenging capacity, reducing power and ferrous ion chelating ability; in addition, the capacity to inhibit 15-lipoxygenase was also assessed. The antihyperglycemic activity was investigated by α-glucosidase assay. Total phenolic contents of 21.68 ± 0.06 and 5.70 ± 0.28 mg/g were determined in the hydromethanolic and ethanolic extracts, respectively. The hydromethanolic extract showed higher free radical scavenging and reducing abilities (EC50 = 452.6 ± 2.7, 140.57 ± 1.45 and 129.45 ± 0.98 μg/mL in DPPH, ABTS and reducing power assays, respectively). The ethanolic extract proved to be more efficient in the ferrous ion chelation, 15-lipoxygenase and α-glucosidase inhibition assays (EC55 = 67.93 ± 0.35, 290.93 ± 2.05 and 8.54 ± 0.06 μg/mL, respectively). Armillaria mellea extracts showed antioxidant and antihyperglycemic potential in in vitro models and therefore they are promising candidates for the development of dietary supplements and pharmaceutical products.

Are high penetrations of commercial cogeneration good for society?

NASA Astrophysics Data System (ADS)

Keen, Jeremy F.; Apt, Jay

2016-12-01

Low natural gas prices, market reports and evidence from New York State suggest that the number of commercial combined heat and power (CHP) installations in the United States will increase by 2%-9% annually over the next decade. We investigate how increasing commercial CHP penetrations may affect net emissions, the distribution network, and total system energy costs. We constructed an integrated planning and operations model that maximizes owner profit through sizing and operation of CHP on a realistic distribution feeder in New York. We find that a greater penetration of CHP reduces both total system energy costs and network congestion. Commercial buildings often have low and inconsistent heat loads, which can cause low fuel utilization efficiencies, low CHP rates-of-return and diminishing avoided emissions as CHP penetration increases. In the northeast, without policy intervention, a 5% penetration of small commercially owned CHP would increase CO2 emissions by 2% relative to the bulk power grid. Low emission CHP installations can be encouraged with incentives that promote CHP operation only during times of high heat loads. Time-varying rates, such as time-of-day and seasonal rates, are one option and were shown to reduce customer emissions without reducing profits. In contrast, natural gas rate discounts, a common incentive for industrial CHP in some states, can encourage CHP operation during low heat loads and thus increase emissions.

Solar-Diesel Hybrid Power System Optimization and Experimental Validation

NASA Astrophysics Data System (ADS)

Jacobus, Headley Stewart

As of 2008 1.46 billion people, or 22 percent of the World's population, were without electricity. Many of these people live in remote areas where decentralized generation is the only method of electrification. Most mini-grids are powered by diesel generators, but new hybrid power systems are becoming a reliable method to incorporate renewable energy while also reducing total system cost. This thesis quantifies the measurable Operational Costs for an experimental hybrid power system in Sierra Leone. Two software programs, Hybrid2 and HOMER, are used during the system design and subsequent analysis. Experimental data from the installed system is used to validate the two programs and to quantify the savings created by each component within the hybrid system. This thesis bridges the gap between design optimization studies that frequently lack subsequent validation and experimental hybrid system performance studies.

Powering a Home with Just 25 Watts of Solar PV. Super-Efficient Appliances Can Enable Expanded Off-Grid Energy Service Using Small Solar Power Systems

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

Phadke, Amol A.; Jacobson, Arne; Park, Won Young

Highly efficient direct current (DC) appliances have the potential to dramatically increase the affordability of off-grid solar power systems used for rural electrification in developing countries by reducing the size of the systems required. For example, the combined power requirement of a highly efficient color TV, four DC light emitting diode (LED) lamps, a mobile phone charger, and a radio is approximately 18 watts and can be supported by a small solar power system (at 27 watts peak, Wp). Price declines and efficiency advances in LED technology are already enabling rapidly increased use of small off-grid lighting systems in Africamore » and Asia. Similar progress is also possible for larger household-scale solar home systems that power appliances such as lights, TVs, fans, radios, and mobile phones. When super-efficient appliances are used, the total cost of solar home systems and their associated appliances can be reduced by as much as 50%. The results vary according to the appliances used with the system. These findings have critical relevance for efforts to provide modern energy services to the 1.2 billion people worldwide without access to the electrical grid and one billion more with unreliable access. However, policy and market support are needed to realize rapid adoption of super-efficient appliances.« less

Health Cost Containment, Wellness, and the 1990s.

ERIC Educational Resources Information Center

Stasica, Edward R.

Virtually every employer has it in their power to reduce their employee health care costs by 10-20 percent or more. The solution to the rising health care costs problem is a total health care system. Most cost savings potential will be centered in three areas: control of wasteful and often harmful use of the health care system; provider price…

Estimating Energy Consumption of Mobile Fluid Power in the United States

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

Lynch, Lauren; Zigler, Bradley T.

This report estimates the market size and energy consumption of mobile off-road applications utilizing hydraulic fluid power, and summarizes technology gaps and implementation barriers. Mobile fluid power is the use of hydraulic fluids under pressure to transmit power in mobile equipment applications. The mobile off-road fluid power sector includes various uses of hydraulic fluid power equipment with fundamentally diverse end-use application and operational requirements, such as a skid steer loader, a wheel loader or an agriculture tractor. The agriculture and construction segments dominate the mobile off-road fluid power market in component unit sales volume. An estimated range of energy consumedmore » by the mobile off-road fluid power sector is 0.36 - 1.8 quads per year, which was 1.3 percent - 6.5 percent of the total energy consumed in 2016 by the transportation sector. Opportunities for efficiency improvements within the fluid power system result from needs to level and reduce the peak system load requirements and develop new technologies to reduce fluid power system level losses, both of which may be facilitated by characterizing duty cycles to define standardized performance test methods. There are currently no commonly accepted standardized test methods for evaluating equipment level efficiency over a duty cycle. The off-road transportation sector currently meets criteria emissions requirements, and there are no efficiency regulations requiring original equipment manufacturers (OEM) to invest in new architecture development to improve the fuel economy of mobile off-road fluid power systems. In addition, the end-user efficiency interests are outweighed by low equipment purchase or lease price concerns, required payback periods, and reliability and durability requirements of new architecture. Current economics, low market volumes with high product diversity, and regulation compliance challenge OEM investment in commercialization of new architecture development.« less

Total phenolic, total flavonoid content, and antioxidant capacity of the leaves of Meyna spinosa Roxb., an Indian medicinal plant.

PubMed

Sen, Saikat; De, Biplab; Devanna, N; Chakraborty, Raja

2013-03-01

The objective of the present study was to determine the total phenolic and total flavonoid contents, and to evaluate the antioxidant potential of different leaf extracts of Meyna spinosa Roxb. ex Link, a traditional medicinal plant of India. Free radical scavenging and antioxidant potential of the methanol, ethyl acetate, and petroleum ether extracts of Meyna spinosa leaves were investigated using several in vitro and ex vivo assays, including the 2, 2-diphenyl-picrylhydrazyl radical scavenging, superoxide anion scavenging, hydroxyl radical scavenging, nitric oxide radical scavenging, hydrogen peroxide scavenging activity, metal chelating assay, and reducing power ability method. Total antioxidant activity of the extracts was estimated by the ferric thiocyanate method. Inhibition assay of lipid peroxidation and oxidative hemolysis were also performed to confirm the protective effect of the extracts. Total phenolic and total flavonoid contents of the extracts were estimated using standard chemical assay procedures. Methanol extracts showed the highest polyphenolic content and possessed the better antioxidant activity than the other two extracts. Total phenolic and total flavonoid contents in the methanol extract were (90.08 ± 0.44) mg gallic acid equivalents/g and (58.50 ± 0.09) mg quercetin equivalents/g, respectively. The IC50 of the methanol extract in the DPPH(·), superoxide anion, hydroxyl radical, nitric oxide radical, hydrogen peroxide scavenging activity and metal chelating assays were (16.4 ± 0.41), (35.9 ± 0.19), (24.1 ± 0.33), (23.7 ± 0.09), (126.8 ± 2.92), and (117.2 ± 1.01) μg·mL(-1), respectively. The methanol extract showed potent reducing power ability, total antioxidant activity, and significantly inhibit lipid peroxidation and oxidative hemolysis which was similar to that of standards. The results indicated a direct correlation between the antioxidant activity and the polyphenolic content of the extracts, which may the foremost contributors to the antioxidant activity of the plant. The present study confirmed that the methanol extract of Meyna spinosa leaves is a potential source of natural antioxidants. Copyright © 2013 China Pharmaceutical University. Published by Elsevier B.V. All rights reserved.

Development of a solar-powered residential air conditioner: Economic analysis

NASA Technical Reports Server (NTRS)

1975-01-01

The results of investigations aimed at the development of cost models to be used in the economic assessment of Rankine-powered air conditioning systems for residential application are summarized. The rationale used in the development of the cost model was to: (1) collect cost data on complete systems and on the major equipment used in these systems; (2) reduce these data and establish relationships between cost and other engineering parameters such as weight, size, power level, etc; and (3) derive simple correlations from which cost-to-the-user can be calculated from performance requirements. The equipment considered in the survey included heat exchangers, fans, motors, and turbocompressors. This kind of hardware represents more than 2/3 of the total cost of conventional air conditioners.

Air quality and climate benefits of long-distance electricity transmission in China

NASA Astrophysics Data System (ADS)

Peng, Wei; Yuan, Jiahai; Zhao, Yu; Lin, Meiyun; Zhang, Qiang; Victor, David G.; Mauzerall, Denise L.

2017-06-01

China is the world’s top carbon emitter and suffers from severe air pollution. It has recently made commitments to improve air quality and to peak its CO2 emissions by 2030. We examine one strategy that can potentially address both issues—utilizing long-distance electricity transmission to bring renewable power to the polluted eastern provinces. Based on an integrated assessment using state-of-the-science atmospheric modeling and recent epidemiological evidence, we find that transmitting a hybrid of renewable (60%) and coal power (40%) (Hybrid-by-wire) reduces 16% more national air-pollution-associated deaths and decreases three times more carbon emissions than transmitting only coal-based electricity. Moreover, although we find that transmitting coal power (Coal-by-Wire, CbW) is slightly more effective at reducing air pollution impacts than replacing old coal power plants with newer cleaner ones in the east (Coal-by-Rail, CbR) (CbW achieves a 6% greater reduction in national total air-pollution-related mortalities than CbR), both coal scenarios have approximately the same carbon emissions. We thus demonstrate that coordinating transmission planning with renewable energy deployment is critical to maximize both local air quality benefits and global climate benefits.

Results of closed cycle MHD power generation test with a helium-cesium working fluid

NASA Technical Reports Server (NTRS)

Sovie, R. J.

1977-01-01

The cross sectional dimensions of the MHD channel in the NASA Lewis closed loop facility were reduced to 3.8 x 11.4 cm. Tests were run in this channel using a helium-cesium working fluid at stagnation pressures of 160,000 n/M2, stagnation temperatures of 2000-2060 K and an entrance Mach number of 0.36. In these tests Faraday open circuit voltages of 200 V were measured which correspond to a Faraday field of 1750 V/M. Power generation tests were run for different groups of electrode configurations and channel lengths. Hall fields up to 1450 V/M were generated. Power extraction per electrode of 183 W and power densities of 1.7 MW/M3 were obtained. A total power output of 2 kW was generated for tests with 14 electrodes. The power densities obtained in this channel represent a factor of 3 improvement over those previously reported for the M = 0.2 channel.

An Implanted, Stimulated Muscle Powered Piezoelectric Generator

NASA Technical Reports Server (NTRS)

Lewandowski, Beth; Gustafson, Kenneth; Kilgore, Kevin

2007-01-01

A totally implantable piezoelectric generator system able to harness power from electrically activated muscle could be used to augment the power systems of implanted medical devices, such as neural prostheses, by reducing the number of battery replacement surgeries or by allowing periods of untethered functionality. The features of our generator design are no moving parts and the use of a portion of the generated power for system operation and regulation. A software model of the system has been developed and simulations have been performed to predict the output power as the system parameters were varied within their constraints. Mechanical forces that mimic muscle forces have been experimentally applied to a piezoelectric generator to verify the accuracy of the simulations and to explore losses due to mechanical coupling. Depending on the selection of system parameters, software simulations predict that this generator concept can generate up to approximately 700 W of power, which is greater than the power necessary to drive the generator, conservatively estimated to be 50 W. These results suggest that this concept has the potential to be an implantable, self-replenishing power source and further investigation is underway.

Performance of an Active Noise Control System for Fan Tones Using Vane Actuators

NASA Technical Reports Server (NTRS)

Sutliff, Daniel L.; Curtis, Alan R. D.; Heidelberg, Laurence J.; Remington, Paul J.

2000-01-01

An Active Noise Control (ANC) system for ducted fan noise was built that uses actuators located in stator vanes. The custom designed actuators A,ere piezoelectric benders manufactured using THUNDER technology. The ANC system was tested in the NASA Active Noise Control Fan rig. A total of 168 actuators in 28 stator vanes were used (six per vane). Simultaneous inlet and exhaust acoustic power level reductions were demonstrated for a fan modal structure that contained two radial modes in each direction. Total circumferential mode power levels were reduced by up to 9 dB in the inlet and 3 dB in the exhaust. The corresponding total 2BPF tone level reductions were by 6 dB in the inlet and 2 dB in the exhaust. Farfield sound pressure level reductions of up to 17 dB were achieved at the peak mode lobe angle. The performance of the system was limited by the constraints of the power amplifiers and the presence of control spillover. Simpler control/actuator systems using carefully selected subsets of the full system and random simulated failures of up to 7% of the actuators were investigated. (The actuators were robust and none failed during the test). Useful reductions still occurred under these conditions.

New design for inertial piezoelectric motors

NASA Astrophysics Data System (ADS)

Liu, Lige; Ge, Weifeng; Meng, Wenjie; Hou, Yubin; Zhang, Jing; Lu, Qingyou

2018-03-01

We have designed, implemented, and tested a novel inertial piezoelectric motor (IPM) that is the first IPM to have controllable total friction force, which means that it sticks with large total friction forces and slips with severely reduced total friction forces. This allows the IPM to work with greater robustness and produce a larger output force at a lower threshold voltage while also providing higher rigidity. This is a new IPM design that means that the total friction force can be dramatically reduced or even canceled where necessary by pushing the clamping points at the ends of a piezoelectric tube that contains the sliding shaft inside it in the opposite directions during piezoelectric deformation. Therefore, when the shaft is propelled forward by another exterior piezoelectric tube, the inner piezoelectric tube can deform to reduce the total friction force acting on the shaft instantly and cause more effective stepping movement of the shaft. While our new IPM requires the addition of another piezoelectric tube, which leads to an increase in volume of 120% when compared with traditional IPMs, the average step size has increased by more than 400% and the threshold voltage has decreased by more than 50 V. The improvement in performance is far more significant than the increase in volume. This enhanced performance will allow the proposed IPM to work under large load conditions where a simple and powerful piezoelectric motor is needed.

Water use at pulverized coal power plants with postcombustion carbon capture and storage.

PubMed

Zhai, Haibo; Rubin, Edward S; Versteeg, Peter L

2011-03-15

Coal-fired power plants account for nearly 50% of U.S. electricity supply and about a third of U.S. emissions of CO(2), the major greenhouse gas (GHG) associated with global climate change. Thermal power plants also account for 39% of all freshwater withdrawals in the U.S. To reduce GHG emissions from coal-fired plants, postcombustion carbon capture and storage (CCS) systems are receiving considerable attention. Current commercial amine-based capture systems require water for cooling and other operations that add to power plant water requirements. This paper characterizes and quantifies water use at coal-burning power plants with and without CCS and investigates key parameters that influence water consumption. Analytical models are presented to quantify water use for major unit operations. Case study results show that, for power plants with conventional wet cooling towers, approximately 80% of total plant water withdrawals and 86% of plant water consumption is for cooling. The addition of an amine-based CCS system would approximately double the consumptive water use of the plant. Replacing wet towers with air-cooled condensers for dry cooling would reduce plant water use by about 80% (without CCS) to about 40% (with CCS). However, the cooling system capital cost would approximately triple, although costs are highly dependent on site-specific characteristics. The potential for water use reductions with CCS is explored via sensitivity analyses of plant efficiency and other key design parameters that affect water resource management for the electric power industry.

Thickness-self-controlled synthesis of porous transparent polyaniline-reduced graphene oxide composites towards advanced bifacial dye-sensitized solar cells

NASA Astrophysics Data System (ADS)

Wang, Yu-Sheng; Li, Shin-Ming; Hsiao, Sheng-Tsung; Liao, Wei-Hao; Yang, Shin-Yi; Tien, Hsi-Wen; Ma, Chen-Chi M.; Hu, Chi-Chang

2014-08-01

A powerful synthesis strategy is proposed for fabricating porous polyaniline-reduced graphene oxide (PANI-RGO) composites with transparency up to 80% and thickness from 300 to 1000 nm for the counter electrode (CE) of bifacial dye-sensitizing solar cells (DSSCs). The first step is to combine the in-situ positive charge transformation of graphene oxide (GO) through aniline (ANI) prepolymerization and the electrostatic adsorption of ANI oligomer-GO to effectively control the thickness of ultrathin PANI-GO films by adjusting pH of the polymerization media. In the second step, PANI-GO films are reduced with hydroiodic acid to simultaneously enhance the apparent redox activity for the I3-/I- couple and their electronic conductivity. Incorporating the RGO increases the transparency of PANI and facilitates the light-harvesting from the rear side. A DSSC assembled with such a transparent PANI-RGO CE exhibits an excellent efficiency of 7.84%, comparable to 8.19% for a semi-transparent Pt-based DSSC. The high light-harvesting ability of PANI-RGO enhances the efficiency retention between rear- and front-illumination modes to 76.7%, compared with 69.1% for a PANI-based DSSC. The higher retention reduces the power-to-weight ratio and the total cost of bifacial DSSCs, which is also promising in other applications, such as windows, power generators, and panel screens.

High Efficiency Microwave Power Amplifier: From the Lab to Industry

NASA Technical Reports Server (NTRS)

Sims, William Herbert, III; Bell, Joseph L. (Technical Monitor)

2001-01-01

Since the beginnings of space travel, various microwave power amplifier designs have been employed. These included Class-A, -B, and -C bias arrangements. However, shared limitation of these topologies is the inherent high total consumption of input power associated with the generation of radio frequency (RF)/microwave power. The power amplifier has always been the largest drain for the limited available power on the spacecraft. Typically, the conversion efficiency of a microwave power amplifier is 10 to 20%. For a typical microwave power amplifier of 20 watts, input DC power of at least 100 watts is required. Such a large demand for input power suggests that a better method of RF/microwave power generation is required. The price paid for using a linear amplifier where high linearity is unnecessary includes higher initial and operating costs, lower DC-to-RF conversion efficiency, high power consumption, higher power dissipation and the accompanying need for higher capacity heat removal means, and an amplifier that is more prone to parasitic oscillation. The first use of a higher efficiency mode of power generation was described by Baxandall in 1959. This higher efficiency mode, Class-D, is achieved through distinct switching techniques to reduce the power losses associated with switching, conduction, and gate drive losses of a given transistor.

Theoretical analysis of phase locking in an array of globally coupled lasers

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

Vysotskii, D V; Elkin, N N; Napartovich, A P

2013-09-30

A model of an array of globally coupled fibre lasers, with the same fraction of the total output beam power injected into each laser, is considered. Phase self-locking of the laser array makes it possible to increase the brightness of the total output beam without any devices for controlling the phases of output beams, which significantly complicate the laser system. The spread of the laser optical lengths is several hundreds of wavelengths (or even more); within the theory of hollow cavities, this spread should lead to a fast decrease in the total power with an increase in the number ofmore » lasers. The presence of the active medium may reduce this drop to a great extent due to the self-tuning of the laser array radiation wavelength to a value providing a maximum gain for the array lasing mode. The optical length of each element is assumed to be random. The increase in the phase-locking efficiency due to the gain saturation is explained based on the probabilistic approach. An iterative procedure is developed to find the array output power in the presence of steady-state phase locking. Calculations for different values of small-signal gain and the output-power fraction spent on global coupling are performed. It is shown that, when this fraction amounts to ∼20 % – 30 %, phase locking of up to 20 fibre lasers can be implemented with an efficiency as high as 70 %. (control of laser radiation parameters)« less

Ion accelerator system mounting design and operating characteristics for a 5 kW 30-cm xenon ion engine

NASA Technical Reports Server (NTRS)

Aston, Graeme; Brophy, John R.

1987-01-01

Results from a series of experiments to determine the effect of accelerator grid mount geometry on the performance of the J-series ion optics assembly are described. Three mounting schemes, two flexible and one rigid, are compared for their relative ion extraction capability over a range of total accelerating voltages. The largest ion beam current, for the maximum total voltage investigated, is shown to occur using one of the flexible grid mounting geometries. However, at lower total voltages and reduced engine input power levels, the original rigid J-series ion optics accelerator grid mounts result in marginally better grid system performance at the same cold interelectrode gap.

Evaluation of antioxidant capacity and phenol content in jackfruit (Artocarpus heterophyllus Lam.) fruit pulp.

PubMed

Jagtap, Umesh B; Panaskar, Shrimant N; Bapat, V A

2010-06-01

The antioxidant capacity of jackfruit (Artocarpus heterophyllus Lam. Fam. Moracae) fruit pulp (JFP) obtained from Western Ghats India was determined by evaluating the scavenging activity using 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric reducing power assays and N, N-dimethyl-p-phenylendiamine (DMPD) radical cation decolorization assay. JFP was analyzed for total phenolic content (TPC) and total flavonoids content (TFC). The ethanol and water are the best solvents for the extracting phenols and flavonoids from the JFP. The antioxidant activities of JFP extracts were correlated with the total phenolic and flavonoids content. The results indicated that the jackfruit pulp is one natural source of antioxidant compounds.

A low-power high-sensitivity analog front-end for PPG sensor.

PubMed

Binghui Lin; Atef, Mohamed; Guoxing Wang

2017-07-01

This paper presents a low-power analog front-end (AFE) photoplethysmography (PPG) sensor fabricated in 0.35 μm CMOS process. The AFE amplifies the weak photocurrent from the photodiode (PD) and converts it to a strong voltage at the output. In order to decrease the power consumption, the circuits are designed in subthreshold region; so the total biasing current of the AFE is 10 μ A. Since the large input DC photocurrent is a big issue for the PPG sensing circuit, we apply a DC photocurrent rejection technique by adding a DC current-cancellation loop to reject the large DC photocurrent up to 10 μA. In addition, a pseudo resistor is used to reduce the high-pass corner frequency below 0.5 Hz and Gm-C filter is adapted to reject the out-of-band noise higher than 16 Hz. For the whole sensor, the amplifier chain can achieve a total gain of 140 dBμ and an input integrated noise current of 68.87 pA rms up to 16 Hz.

ASSESSMENT OF OXIDATIVE STRESS IN EARLY AND LATE ONSET PRE-ECLAMPSIA AMONG GHANAIAN WOMEN.

PubMed

Tetteh, P W; Adu-Bonsaffoh, K; Antwi-Boasiako, C; Antwi, D A; Gyan, B; Obed, S A

2015-01-01

Pre-eclampsia is a multisystem pregnancy-related disorder with multiple theories regarding its aetiology resulting in lack of reliable screening tests and well-established measures for primary prevention. However, oxidative stress is increasingly being implicated in the pathogenesi of pre-eclampsia although conflicting findings have been reported. To determine and compare the levels of oxidative stress in early and late onset pre-eclampsia by measuring urinary excretion of isoprostane and total antioxidant power (TAP) in a cohort of pre-eclamptic women at Korle Bu Teaching Hospital. This was a cross-sectional study conducted at Korle-Bu Teaching Hospital, Accra, Ghana involving pre-eclamptic women between the ages 18 and 45 years who gave written informed consent. Urinary isoprostane levels were determined using an enzyme-linked immunosorbent assay (ELISA) kit whereas the Total Anti-oxidant Power in urine samples was determined using Total Antioxidant Power Colorimetric Microplate Assay kit. The data obtained were analyzed using MEGASTAT statistical software package. We included 102 pre-eclamptic women comprising 68 (66.7%) and 34 (33.3%) with early-onset and late-onset pre-eclampsia respectively. There were no statistically significant differences between the mean maternal age, haematological indices, serum ALT, AST, ALT, albumin, urea, creatinine uric acid and total protein at the time of diagnosis. The mean gestational age at diagnosis of early and late onset pre-eclampsia were 31.65 ± 0.41 and 38.03 ± 0.21 respectively (p ˂ 0.001). Also, there were statistically significant differences between the diastolic blood pressure (BP), systolic BP and mean arterial pressure (MAP) at diagnosis of pre-eclampsia in the two categories. The mean urinary Isoprostane excretion was significantly higher in the early onset pre-eclamptic group (3.04 ± 0.34 ng/mg Cr) compared to that of the late onset pre-eclamptic group (2.36 ± 0.45 ng/mg Cr), (p=0.019). Urinary total antioxidant power (TAP) in early onset PE (1.64 ± 0.06) was lower but not significantly different from that of late onset PE (1.74 ± 0.09) with p = 0.369. Significantly increased urinary isoprostane excretion was detected in early onset pre-eclampsia compared to late onset pre-eclampsia, suggestive of increased oxidative stress in the former. However, there was no significant difference in total anti-oxidant power between the two categories of pre-eclampsia women although there was a tendency of reduced total antioxidant power in the women with early onset pre-ecalmpsia.

Electrocortical effects of MDMA are potentiated by acoustic stimulation in rats

PubMed Central

Iannone, Michelangelo; Bulotta, Stefania; Paolino, Donatella; Zito, Maria Cristina; Gratteri, Santo; Costanzo, Francesco S; Rotiroti, Domenicantonio

2006-01-01

Background 3,4-Methylenedioxymethamphetamine (MDMA; ecstasy) is known for its toxicological, psychopathological and abuse potential. Some environmental conditions, e.g. acoustic stimulation typical of the "rave scene" can influence the toxicity of this drug. Results We investigated the effects of low doses of MDMA in vivo using Wistar rats in the absence of acoustic stimulation (white noise; 95 Db) demonstrating that ecstasy is able to induce a significant activation (reduction of Electrocortical total power) of the telencephalic cortex that spontaneously reverts in the absence of sensorial stimuli, whereas it persists for several days if, in addition to MDMA, the animals are exposed to acoustic stimulation. Conclusion Our data demonstrate that low doses of MDMA are able to reduce electrocortical total power, and that this effect is potentiated by sensorial stimuli commonly present in certain environments, such as rave parties. PMID:16480519

Insulin-induced hypoglycemia and stress oxidative state in healthy people.

PubMed

Yousefzade, Gholamreza; Nakhaee, Akram

2012-12-01

The purpose of this study is to assess the immediate effects of insulin-induced hypoglycemia on the natural antioxidant superoxide dismutase activity, malondialdehyde concentration, total antioxidative capacity and total thiol group concentration in young healthy subjects. In this clinical trial, 16 healthy men with the mean age of 29.3 ± 5.3 years (range 21-39 years) became volunteers to participate the study. Hypoglycemia was induced by intravenous administration of regular insulin 0.1 U/kg. Before and after inducing hypoglycemia, SOD activity was determined in red blood cells, whereas the MDA concentration was determined by thiobarbituric acid reactive substance method, total thiol groups by high-performance liquid chromatography method and total antioxidant capacity by ferric reducing/antioxidant power. A significant increase was seen in the TBARS levels following insulin-induced hypoglycemia (0.19 ± 0.07 vs. 0.38 ± 0.16 nmol/g, P < 0.001), while a significant decrement occurred in the antioxidant power (FRAP value) (321.4 ± 63.4 vs. 231.4 ± 57.5, P < 0.001), total thiol concentration (2.3 ± 0.8 vs. 1.3 ± 0.5, P = 0.001) and SOD enzyme activity (29.4 ± 8.2 vs. 23.1 ± 6.1, P < 0.001) subsequent the hypoglycemia with insulin.

Ultra-compact high-performance MCT MWIR engine

NASA Astrophysics Data System (ADS)

Lutz, H.; Breiter, R.; Eich, D.; Figgemeier, H.; Oelmaier, R.; Rutzinger, S.; Schenk, H.; Wendler, J.

2017-02-01

Size, weight and power (SWaP) reduction is highly desired by applications such as sights for the dismounted soldier or small gimbals for UAVs. But why have high performance and small size of IR systems inevitably exclude each other? Namely, recent development progress in the fields of miniature cryocoolers, short dewars and high operating temperature (HOT) FPAs combined with pitch size reduction opens the door for very compact MWIR-modules while keeping high electro-optical performance. Now, AIM has realized first prototypes of an ultra-compact high-performance MWIR engine in a total volume of only 18cl (60mm length x 60mm height x 50mm width). Impressive SWaP characteristics are completed by a total weight below 400g and a power consumption < 4W in basic imaging mode. The engine consists of a XGA-format (1024x768) MCT detector array with 10μm pitch and a low power consuming ROIC. It is cooled down to a typical operating temperature of 160K by the miniature linear cryocooler SX020. The dewar uses a short coldfinger and is designed to reduce the heat load as much as possible. The cooler drive electronics is implemented in the CCE layout in order to reduce the required space of the printed boards and to save power. Uncorrected 14bit video data is provided via Camera Link. Optionally, a small image processing board can be stacked on top of the CCE to gain access to basic functions such as BPR, 2- point NUC and dynamic reduction. This paper will present the design, functionalities and performance data of the ultra-compact MCT MWIR engine operated at HOT.

Heuristic approaches for energy-efficient shared restoration in WDM networks

NASA Astrophysics Data System (ADS)

Alilou, Shahab

In recent years, there has been ongoing research on the design of energy-efficient Wavelength Division Multiplexing (WDM) networks. The explosive growth of Internet traffic has led to increased power consumption of network components. Network survivability has also been a relevant research topic, as it plays a crucial role in assuring continuity of service with no disruption, regardless of network component failure. Network survivability mechanisms tend to utilize considerable resources such as spare capacity in order to protect and restore information. This thesis investigates techniques for reducing energy demand and enhancing energy efficiency in the context of network survivability. We propose two novel heuristic energy-efficient shared protection approaches for WDM networks. These approaches intend to save energy by setting on sleep mode devices that are not being used while providing shared backup paths to satisfy network survivability. The first approach exploits properties of a math series in order to assign weight to the network links. It aims at reducing power consumption at the network indirectly by aggregating traffic on a set of nodes and links with high traffic load level. Routing traffic on links and nodes that are already under utilization makes it possible for the links and nodes with no load to be set on sleep mode. The second approach is intended to dynamically route traffic through nodes and links with high traffic load level. Similar to the first approach, this approach computes a pair of paths for every newly arrived demand. It computes these paths for every new demand by comparing the power consumption of nodes and links in the network before the demand arrives with their potential power consumption if they are chosen along the paths of this demand. Simulations of two different networks were used to compare the total network power consumption obtained using the proposed techniques against a standard shared-path restoration scheme. Shared-path restoration is a network survivability method in which a link-disjoint backup path and wavelength is reserved at the time of call setup for a working path. However, in order to reduce spare capacity consumption, this reserved backup path and wavelength may be shared with other backup paths. Pool Sharing Scheme (PSS) is employed to implement shared-path restoration scheme [1]. In an optical network, the failure of a single link leads to the failure of all the lightpaths that pass through that particular link. PSS ensures that the amount of backup bandwidth required on a link to restore the failed connections will not be more than the total amount of reserved backup bandwidth on that link. Simulation results indicate that the proposed approaches lead to up to 35% power savings in WDM networks when traffic load is low. However, power saving decreases to 14% at high traffic load level. Furthermore, in terms of the total capacity consumption for working paths, PSS outperforms the two proposed approaches, as expected. In terms of total capacity consumption all the approaches behave similarly. In general, at low traffic load level, the two proposed approaches behave similar to PSS in terms of average link load, and the ratio of block demands. Nevertheless, at high traffic load, the proposed approaches result in higher ratio of blocked demands than PSS. They also lead to higher average link load than PSS for the equal number of generated demands.

Mushrooms as possible antioxidant and antimicrobial agents.

PubMed

Kosanić, Marijana; Ranković, Branislav; Dašić, Marko

2012-01-01

The aim of the study is to examine in-vitro antioxidant and antimicrobial activity of the acetonic and methanolic extracts of the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini. Antioxidant activity was evaluated by using free radical scavenging activity and reducing power. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. As a result of the study acetonic extracts from Boletus edulis was more powerful antioxidant activity with IC50 value of 4.72 μg/mL which was similar or greater than the standard antioxidants, ascorbic acid (IC50 = 4.22 μg/mL), BHA (IC50 = 6.42 μg/mL) and α-tocopherol (IC50 = 62.43 μg/mL). Moreover, the tested extracts had effective reducing power. A significant relationship between total phenolic and flavonoid contents and their antioxidative activities was significantly observed. The antimicrobial activity of each extract was estimated by determination of the minimum inhibitory concentration by using microdilution plate method against five species of bacteria and five species of fungi. Generally, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi were 1.25 - 10 mg/ mL. The present study shows that tested mushroom species demonstrated a strong antioxidant and antimicrobial activity. It suggests that mushroom may be used as good sources of natural antioxidants and for pharmaceutical purposes in treating of various deseases.

Enhanced reproducibility of L-mode plasma discharges via physics-model-based q-profile feedback control in DIII-D

NASA Astrophysics Data System (ADS)

Schuster, E.; Wehner, W. P.; Barton, J. E.; Boyer, M. D.; Luce, T. C.; Ferron, J. R.; Holcomb, C. T.; Walker, M. L.; Humphreys, D. A.; Solomon, W. M.; Penaflor, B. G.; Johnson, R. D.

2017-11-01

Recent experiments on DIII-D demonstrate the potential of physics-model-based q-profile control to improve reproducibility of plasma discharges. A combined feedforward  +  feedback control scheme is employed to optimize the current ramp-up phase by consistently achieving target q profiles (Target 1: q_min=1.3, q95=4.4 ; Target 2: q_min=1.65, q95=5.0 ; Target 3: q_min=2.1, q95=6.2 ) at prescribed times during the plasma formation phase (Target 1: t=1.5 s; Target 2: t=1.3 s; Target 3: t=1.0 s). At the core of the control scheme is a nonlinear, first-principles-driven, physics-based, control-oriented model of the plasma dynamics valid for low confinement (L-mode) scenarios. To prevent undesired L-H transitions, a constraint on the maximum allowable total auxiliary power is imposed in addition to the maximum powers for the individual heating and current-drive sources. Experimental results are presented to demonstrate the effectiveness of the combined feedforward  +  feedback control scheme to consistently achieve the desired target profiles at the predefined times. These results also show how the addition of feedback control significantly improves upon the feedforward-only control solution by reducing the matching error and also how the feedback controller is able to reduce the matching error as the constraint on the maximum allowable total auxiliary power is relaxed while keeping the plasma in L-mode.

Bioactive components, antioxidant and DNA damage inhibitory activities of honeys from arid regions.

PubMed

Habib, Hosam M; Al Meqbali, Fatima T; Kamal, Hina; Souka, Usama D; Ibrahim, Wissam H

2014-06-15

Honey serves as a good source of natural antioxidants, which are effective in reducing the risk of occurrence of several diseases. This study was undertaken to address the limited knowledge regarding the polyphenolic content, antioxidant and DNA damage inhibitory activities of honeys produced in arid regions and compare them with well-recognized honeys from non-arid regions. Different types of honey were assessed for their contents of total phenolics, total flavonoids, and certain types of phenolic compounds. The antioxidant capacity of honey was evaluated by ferric-reducing/antioxidant power assay (FRAP), free radical-scavenging activity (DPPH), nitric oxide (NO) radical-scavenging assay, total antioxidant activity, and DNA damage. Results clearly showed significant differences among honeys with all the evaluated parameters. Results also showed that one or more types of honey from arid regions contained higher levels of phenolic compounds, free radical-scavenging activities, or DNA damage inhibitory activities compared with the evaluated honeys from non-arid regions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ultra Clean 1.1MW High Efficiency Natural Gas Engine Powered System

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

Zurlo, James; Lueck, Steve

Dresser, Inc. (GE Energy, Waukesha gas engines) will develop, test, demonstrate, and commercialize a 1.1 Megawatt (MW) natural gas fueled combined heat and power reciprocating engine powered package. This package will feature a total efficiency > 75% and ultra low CARB permitting emissions. Our modular design will cover the 1 – 6 MW size range, and this scalable technology can be used in both smaller and larger engine powered CHP packages. To further advance one of the key advantages of reciprocating engines, the engine, generator and CHP package will be optimized for low initial and operating costs. Dresser, Inc. willmore » leverage the knowledge gained in the DOE - ARES program. Dresser, Inc. will work with commercial, regulatory, and government entities to help break down barriers to wider deployment of CHP. The outcome of this project will be a commercially successful 1.1 MW CHP package with high electrical and total efficiency that will significantly reduce emissions compared to the current central power plant paradigm. Principal objectives by phases for Budget Period 1 include: • Phase 1 – market study to determine optimum system performance, target first cost, lifecycle cost, and creation of a detailed product specification. • Phase 2 – Refinement of the Waukesha CHP system design concepts, identification of critical characteristics, initial evaluation of technical solutions, and risk mitigation plans. Background« less

Use of power of attorney in Scotland.

PubMed

Routh, Rajdeep; Mcneill, Catriona; Jackson, Graham A

2016-08-01

Power of Attorney as a form of surrogate decision making was introduced within the Adults with Incapacity, Scotland Act (2000) to help individuals who lack mental capacity due to illnesses like dementia. Even after a decade, little was known if it has been useful. We sought to find out how useful the power of attorney document has been so far in supporting people when they lose their capacity and identify any barriers. We did a survey and approached a random sample of 5000 attorneys in Scotland. A total of 1226 attorneys responded; 59% of the respondents had never used their powers but still considered it useful for 'peace of mind'. For the majority, the costs of arranging a power of attorney ranged in between £150 and £300. The study confirms that power of attorney is useful to safeguard interests of people when they lose capacity. Costs remain a big barrier. Further studies are required to understand the long-term impact of providing financial support to arrange a power of attorney at an early stage on reducing delayed discharges in hospitals. © The Author(s) 2015.

Antioxidant Activity and Total Phenolic and Flavonoid Content of Various Solvent Extracts from In Vivo and In Vitro Grown Trifolium pratense L. (Red Clover)

PubMed Central

Mat Taha, Rosna; Banisalam, Behrooz

2015-01-01

In the present study the extracts of in vivo and in vitro grown plants as well as callus tissue of red clover were tested for their antioxidant activities, using different extraction solvent and different antioxidant assays. The total flavonoid and phenolic contents as well as extraction yield of the extracts were also investigated to determine their correlation with the antioxidant activity of the extracts. Among all the tested extracts the highest amounts of total phenolic and total flavonoids content were found in methanol extract of in vivo grown plants. The antioxidant activity of tested samples followed the order in vivo plant extract > callus extract > in vitro extract. The highest reducing power, 2,2-azino-bis-(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging, and chelating power were found in methanol extracts of in vivo grown red clover, while the chloroform fraction of in vivo grown plants showed the highest 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging, superoxide anion radical scavenging and hydrogen peroxide scavenging compared to the other tested extracts. A significant correlation was found between the antioxidant activity of extracts and their total phenolic and total flavonoid content. According to the findings, the extract of in vitro culture of red clover especially the callus tissue possesses a comparable antioxidant activity to the in vivo cultured plants' extract. PMID:26064936

The Effect of Economic Inflation on Local Public Library Support in Kentucky, 1967-1976.

ERIC Educational Resources Information Center

Smith, Robert C.

This study was developed on the hypothesis that economic inflation reduced the purchasing power of local support for public libraries from 1967 through fiscal 1976. The total local support for public libraries in each county in each year of the study was adjusted from the reported nominal amount to the relative Consumer Price Index value of 1967…

Short-term benefits from central unit commitment and dispatch: Application to the Southern African Power Pool

NASA Astrophysics Data System (ADS)

Bowen, Brian Hugh

1998-12-01

Electricity utilities in the Southern African region are conscious that gains could be made from more economically efficient trading but have had no tools with which to analyze the effects of a change in policy. This research is the first to provide transparent quantitative techniques to quantify the impacts of new trading arrangements in this region. The study poses a model of the recently formed Southern African Power Pool, built with the collaboration of the region's national utilities to represent each country's demand and generation/transmission system. The multi-region model includes commitment and dispatch from diverse hydrothermal sources over a vast area. Economic gains are determined by comparing the total costs under free-trade conditions with those from the existing fixed-trade bilateral arrangements. The objective function minimizes production costs needed to meet total demand, subject to each utility's constraints for thermal and hydro generation, transmission, load balance and losses. Linearized thermal cost functions are used along with linearized input output hydropower plant curves and hydrothermal on/off status variables to formulate a mixed-integer programming problem. Results from the modeling show that moving to optimal trading patterns could save between 70 million and 130 million per year. With free-trade policies the quantity of power flow between utilities is doubled and maximum usage is made of the hydropower stations thus reducing costs and fuel use. In electricity exporting countries such as Zambia and Mozambique gains from increased trade are achieved which equal 16% and 18% respectively of the value of their total manufactured exports. A sensitivity analysis is conducted on the possible effects of derating generation, derating transmission and reducing water inflows but gains remain large. Maximum economic gains from optimal trading patterns can be achieved by each country allowing centralized control through the newly founded SAPP coordination center. Using standard mixed integer programming solvers makes the cost of such modeling activity easily affordable to each utility in the Southern African pool. This research provides the utilities with the modeling tools to quantify the gains from increased trade and thereby furthers a move towards greater efficiency, faster economic growth and reduced use of fossil fuels.

Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

NASA Astrophysics Data System (ADS)

Pak, A.; Dewald, E. L.; Landen, O. L.; Milovich, J.; Strozzi, D. J.; Berzak Hopkins, L. F.; Bradley, D. K.; Divol, L.; Ho, D. D.; MacKinnon, A. J.; Meezan, N. B.; Michel, P.; Moody, J. D.; Moore, A. S.; Schneider, M. B.; Town, R. P. J.; Hsing, W. W.; Edwards, M. J.

2015-12-01

Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are used to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.

Quantitative method for measuring heat flux emitted from a cryogenic object

DOEpatents

Duncan, Robert V.

1993-01-01

The present invention is a quantitative method for measuring the total heat flux, and of deriving the total power dissipation, of a heat-fluxing object which includes the steps of placing an electrical noise-emitting heat-fluxing object in a liquid helium bath and measuring the superfluid transition temperature of the bath. The temperature of the liquid helium bath is thereafter reduced until some measurable parameter, such as the electrical noise, exhibited by the heat-fluxing object or a temperature-dependent resistive thin film in intimate contact with the heat-fluxing object, becomes greatly reduced. The temperature of the liquid helum bath is measured at this point. The difference between the superfluid transition temperature of the liquid helium bath surrounding the heat-fluxing object, and the temperature of the liquid helium bath when the electrical noise emitted by the heat-fluxing object becomes greatly reduced, is determined. The total heat flux from the heat-fluxing object is determined as a function of this difference between these temperatures. In certain applications, the technique can be used to optimize thermal design parameters of cryogenic electronics, for example, Josephson junction and infra-red sensing devices.

Quantitative method for measuring heat flux emitted from a cryogenic object

DOEpatents

Duncan, R.V.

1993-03-16

The present invention is a quantitative method for measuring the total heat flux, and of deriving the total power dissipation, of a heat-fluxing object which includes the steps of placing an electrical noise-emitting heat-fluxing object in a liquid helium bath and measuring the superfluid transition temperature of the bath. The temperature of the liquid helium bath is thereafter reduced until some measurable parameter, such as the electrical noise, exhibited by the heat-fluxing object or a temperature-dependent resistive thin film in intimate contact with the heat-fluxing object, becomes greatly reduced. The temperature of the liquid helum bath is measured at this point. The difference between the superfluid transition temperature of the liquid helium bath surrounding the heat-fluxing object, and the temperature of the liquid helium bath when the electrical noise emitted by the heat-fluxing object becomes greatly reduced, is determined. The total heat flux from the heat-fluxing object is determined as a function of this difference between these temperatures. In certain applications, the technique can be used to optimize thermal design parameters of cryogenic electronics, for example, Josephson junction and infrared sensing devices.

Electricity generation from bio-treatment of sewage sludge with microbial fuel cell.

PubMed

Jiang, Junqiu; Zhao, Qingliang; Zhang, Jinna; Zhang, Guodong; Lee, Duu-Jong

2009-12-01

A two-chambered microbial fuel cell (MFC) with potassium ferricyanide as its electron acceptor was utilized to degrade excess sewage sludge and to generate electricity. Stable electrical power was produced continuously during operation for 250 h. Total chemical oxygen demand (TCOD) of sludge was reduced by 46.4% when an initial TCOD was 10,850 mg/l. The MFC power output did not significantly depend on process parameters such as substrate concentration, cathode catholyte concentration, and anodic pH. However, the MFC produced power was in close correlation with the soluble chemical oxygen demand (SCOD) of sludge. Furthermore, ultrasonic pretreatment of sludge accelerated organic matter dissolution and, hence, TCOD removal rate in the MFC was increased, but power output was insignificantly enhanced. This study demonstrates that this MFC can generate electricity from sewage sludge over a wide range of process parameters.

Performance evaluation of an evaporative pad greenhouse system for utilization of power plant reject heat

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

Olszewski, M.; Trezek, G.J.

1976-01-01

The overall performance of an evaporative pad greenhouse is considered in terms of the pad heat and mass transfer, the energy budget of the vegetation, and the performance of the power plant. An analytical predictive model for the pad performance was developed utilizing the Merkel total heat approximation. Data obtained from actual greenhouse performance provides an experimental verification of the pad model. Energy balance considerations on the vegetation provide a means of viewing optimal plant growth in terms of the power plant energy dissipation. In general, the results indicate that when an evaporative pad greenhouse system is used for wastemore » heat dispersal, the vegetation can be maintained within its thermal requirement zone, crop irrigation requirements are significantly reduced, and the power plant performance is comparable with conventional closed loop heat rejection systems.« less

Oral and Intravenous Tranexamic Acid Are Equivalent at Reducing Blood Loss Following Total Hip Arthroplasty: A Randomized Controlled Trial.

PubMed

Kayupov, Erdan; Fillingham, Yale A; Okroj, Kamil; Plummer, Darren R; Moric, Mario; Gerlinger, Tad L; Della Valle, Craig J

2017-03-01

Tranexamic acid is an antifibrinolytic that has been shown to reduce blood loss and the need for transfusions when administered intravenously in total hip arthroplasty. Oral formulations of the drug are available at a fraction of the cost of the intravenous preparation. The purpose of this randomized controlled trial was to determine if oral and intravenous formulations of tranexamic acid have equivalent blood-sparing properties. In this double-blinded trial, 89 patients undergoing primary total hip arthroplasty were randomized to receive 1.95 g of tranexamic acid orally 2 hours preoperatively or a 1-g tranexamic acid intravenous bolus in the operating room prior to incision; 6 patients were eventually excluded for protocol deviations, leaving 83 patients available for study. The primary outcome was the reduction of hemoglobin concentration. Power analysis determined that 28 patients were required in each group with a ±1.0 g/dL hemoglobin equivalence margin between groups with an alpha of 5% and a power of 80%. Equivalence analysis was performed with a two one-sided test (TOST) in which a p value of <0.05 indicated equivalence between treatments. Forty-three patients received intravenous tranexamic acid, and 40 patients received oral tranexamic acid. Patient demographic characteristics were similar between groups, suggesting successful randomization. The mean reduction of hemoglobin was similar between oral and intravenous groups (3.67 g/dL compared with 3.53 g/dL; p = 0.0008, equivalence). Similarly, the mean total blood loss was equivalent between oral and intravenous administration (1,339 mL compared with 1,301 mL; p = 0.034, equivalence). Three patients (7.5%) in the oral group and one patient (2.3%) in the intravenous group were transfused, but the difference was not significant (p = 0.35). None of the patients in either group experienced a thromboembolic event. Oral tranexamic acid provides equivalent reductions in blood loss in the setting of primary total hip arthroplasty, at a greatly reduced cost, compared with the intravenous formulation. Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Increased heat dissipation with the X-divertor geometry facilitating detachment onset at lower density in DIII-D

NASA Astrophysics Data System (ADS)

Covele, B.; Kotschenreuther, M.; Mahajan, S.; Valanju, P.; Leonard, A.; Watkins, J.; Makowski, M.; Fenstermacher, M.; Si, H.

2017-08-01

The X-divertor geometry on DIII-D has demonstrated reduced particle and heat fluxes to the target, facilitating detachment onset at 10-20% lower upstream density and higher H-mode pedestal pressure than a standard divertor. SOLPS modeling suggests that this effect cannot be explained by an increase in total connection length alone, but rather by the addition of connection length specifically in the power-dissipating volume near the target, via poloidal flux expansion and flaring. However, poloidal flaring must work synergistically with divertor closure to most effectively reduce the detachment density threshold. The model also points to carbon radiation as the primary driver of power dissipation in divertors on the DIII-D floor, which is consistent with experimental observations. Sustainable divertor detachment at lower density has beneficial consequences for energy confinement and current drive efficiency for core operation, while simultaneously satisfying the exhaust requirements of the plasma-facing components.

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

Covele, Brent; Kotschenreuther, M.; Mahajan, S.

The X-Divertor geometry on DIII-D has demonstrated reduced particle and heat fluxes to the target, facilitating detachment onset at ~20% lower upstream density and higher H-mode pedestal pressure than a standard divertor. SOLPS modeling suggests that this effect cannot be explained by an increase in total connection length alone, but rather by the addition of connection length specifically in the power-dissipating volume near the target, via poloidal flux expansion and flaring. But, poloidal flaring must work synergistically with divertor closure to most effectively reduce the detachment density threshold. Furthermore, the model also points to carbon radiation as the primary drivermore » of power dissipation in divertors on the DIII-D floor, which is consistent with experimental observations. Sustainable divertor detachment at lower density has beneficial consequences for energy confinement and current drive efficiency in the core for advanced tokamak (AT) operation, while simultaneously satisfying the exhaust requirements of the plasma-facing components.« less

Antioxidant Activities of Functional Beverage Concentrates Containing Herbal Medicine Extracts.

PubMed

Park, Seon-Joo; Kim, Mi-Ok; Kim, Jung Hoan; Jeong, Sehyun; Kim, Min Hee; Yang, Su-Jin; Lee, Jongsung; Lee, Hae-Jeung

2017-03-01

This study investigated the antioxidant activity of functional beverage concentrates containing herbal medicine extracts (FBCH) using various antioxidant assays, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radical scavenging activity, and reducing power assay. The total polyphenolic content of FBCH (81.45 mg/100 g) was higher than Ssanghwa tea (SHT, 37.56 mg/100 g). The antioxidant activities of FBCH showed 52.92% DPPH and 55.18% ABTS radical scavenging activities at 100 mg/mL, respectively. FBCH showed significantly higher antioxidant activities compared to the SHT (DPPH, 23.43%; ABTS, 22.21%; reducing power optical density; 0.23, P <0.05). In addition, intracellular reactive oxygen species generation significantly decreased in a concentration-dependent manner following FBCH treatment. These results suggest that the addition of herbal medicine extract contributes to the improved functionality of beverage concentrates.

Antioxidant Characterization of Oak Extracts Combining Spectrophotometric Assays and Chemometrics

PubMed Central

Popović, Boris M.; Štajner, Dubravka; Orlović, Saša; Galić, Zoran

2013-01-01

Antioxidant characteristics of leaves, twigs, and acorns from two Serbian oak species Quercus robur L. and Quercus petraea L. from Vojvodina province (northern Serbia) were investigated. 80% ethanol (in water) extracts were used for antiradical power (ARP) determinations against DPPH•, •NO, and O2 •− radicals, ferric reducing antioxidant power (FRAP), total phenol, tannin, flavonoid, and proanthocyanidin contents. Permanganate reducing antioxidant capacity (PRAC) was determined using water extracts. Beside, mentioned parameters, soluble proteins, lipid peroxidation (LP), pigments and proline contents were also determined. The data of different procedures were compared and analyzed by multivariate techniques (correlation matrix calculation and principal component analysis (PCA)). PCA found that investigated organs of two different oak tree species possess similar antioxidant characteristics. The superior antioxidant characteristics showed oak leaves over twigs and acorns and seem to be promising source of antioxidants with possible use in industry and pharmacy. PMID:24453789

Antioxidant properties of some medicinal plants: Prangos ferulacea (Apiaceae), Sedum sempervivoides (Crassulaceae), Malva neglecta (Malvaceae), Cruciata taurica (Rubiaceae), Rosa pimpinellifolia (Rosaceae), Galium verum subsp. verum (Rubiaceae), Urtica dioica (Urticaceae).

PubMed

Mavi, Ahmet; Terzi, Zeynep; Ozgen, Ufuk; Yildirim, Ali; Coşkun, Maksut

2004-05-01

Antioxidant and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities, reducing powers and the amount of total phenolic compounds of aqueous and/or methanolic extracts of some medicinal plants used in Eastern Turkey were studied. These plants are Prangos ferulacea (CASIR), Sedum sempervivoides (HOROZ LELESI), Malva neglecta (EBEMGUMECI), Cruciata taurica (SARILIK OTU), Rosa pimpinellifolia (KOYUN GOZU), Galium verum subsp. verum (MADAVUR OTU), Urtica dioica (ISIRGAN). The highest peroxidation inhibitions were shown by aqueous extracts of C. taurica and R. pimpinellifolia (IC(50): 0.00022 mg/l and IC(50): 23 mg/l, respectively). However, the highest DPPH radical scavenging activity, reducing power and the amount of phenolic compounds were shown by R. pimpinellifolia. The lowest antioxidant properties were shown by aqueous extract of M. neglecta.

Silymarin Ameliorates Oxidative Stress and Enhances Antioxidant Defense System Capacity in Cadmium-Treated Mice.

PubMed

Farjad, Elham; Momeni, Hamid Reza

2018-10-01

Cadmium is an environmental pollutant which induces oxidative stress while silymarin as an antioxidant is able to scavenge free radicals. The aim of the present study was to investigate the effect of silymarin on oxidative stress markers and antioxidant defense system capacity in mice treated with cadmium chloride. In this experimental study, adult mice were divided into four groups as follow: i. Control, ii. Cadmium chloride (5 mg/kg b.w., s.c.), iii. Silymarin+cadmium chloride, and iv. Silymarin (100 mg/kg b.w., i.p.). Mice were treated with cadmium chloride for 24 hours and silymarin was administered 24 hours before the cadmium. Blood samples were then collected from the experimental groups and their sera were prepared. To investigate oxidative stress markers in the serum, the amount of malondialdehyde (MDA) and thiol groups (-SH) were evaluated. To measure the total antioxidant power in the serum, Ferric Reducing/ Antioxidant Power (FRAP) method was used. In addition, the activity of enzymes including catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GPx) was assessed to evaluate serum antioxidant defense power. In the cadmium-treated group, the amount of MDA significantly increased as compared to the control group. In silymarin+cadmium group, silymarin significantly ameliorated the level of MDA compared to the cadmium group. In addition, cadmium significantly reduced serum FRAP, the activity of antioxidant defense system enzymes and thiol groups compared to the control. In silymarin+cadmium group, silymarin could significantly reverse the reduction of these markers compared to the cadmium group. Administration of silymarin alone caused a significant increase in serum FRAP, the activity of antioxidant defense system enzymes and thiol groups compared to the control group. Silymarin as a powerful antioxidant reverses the toxic effect of cadmium on the serum levels of lipid peroxidation, total antioxidant power, antioxidant defense system enzymes activity and thiol groups. Copyright© by Royan Institute. All rights reserved.

On the Path to SunShot. The Environmental and Public Health Benefits of Achieving High Solar Penetrations in the United States

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

Wiser, Ryan; Mai, Trieu; Millstein, Dev

Compared with fossil fuel generators, photovoltaics (PV) and concentrating solar power (CSP) produce far lower lifecycle levels of greenhouse gas (GHG) emissions and harmful pollutants including fine particular matter (PM2.5), sulfur dioxide (SO 2), and nitrogen oxides (NO x). In this report, we monetize the emission reductions from achieving the U.S. Department of Energy's SunShot deployment goals: 14% of U.S. electricity demand met by solar in 2030 and 27% in 2050. We estimate that achieving these goals could reduce cumulative power-sector GHG emissions by 10% between 2015 and 2050, resulting in savings of $238-$252 billion. This is equivalent to 2.0-2.2more » cents per kilowatt-hour of solar installed (cents/kWh-solar). Similarly, realizing these levels of solar deployment could reduce cumulative power-sector emissions of PM2.5 by 8%, SO 2 by 9%, and NOx by 11% between 2015 and 2050. This could produce $167 billion in savings from lower future health and environmental damages, or 1.4 cents/kWh-solar--while also preventing 25,000-59,000 premature deaths. To put this in perspective, this estimated combined benefit of 3.5 cents/kWh-solar due to SunShot-level solar deployment is approximately equal to the additional levelized cost of electricity reduction needed to make unsubsidized utility-scale solar competitive with conventional generators today. In addition, the analysis shows that achieving the SunShot goals could save 4% of total power-sector water withdrawals and 9% of total power-sector water consumption over the 2015-2050 period--a particularly important consideration for arid states where substantial solar will be deployed. These results have potential implications for policy innovation and the economic competitiveness of solar and other generation technologies.« less

Biomechanical walking mechanisms underlying the metabolic reduction caused by an autonomous exoskeleton.

PubMed

Mooney, Luke M; Herr, Hugh M

2016-01-28

Ankle exoskeletons can now reduce the metabolic cost of walking in humans without leg disability, but the biomechanical mechanisms that underlie this augmentation are not fully understood. In this study, we analyze the energetics and lower limb mechanics of human study participants walking with and without an active autonomous ankle exoskeleton previously shown to reduce the metabolic cost of walking. We measured the metabolic, kinetic and kinematic effects of wearing a battery powered bilateral ankle exoskeleton. Six participants walked on a level treadmill at 1.4 m/s under three conditions: exoskeleton not worn, exoskeleton worn in a powered-on state, and exoskeleton worn in a powered-off state. Metabolic rates were measured with a portable pulmonary gas exchange unit, body marker positions with a motion capture system, and ground reaction forces with a force-plate instrumented treadmill. Inverse dynamics were then used to estimate ankle, knee and hip torques and mechanical powers. The active ankle exoskeleton provided a mean positive power of 0.105 ± 0.008 W/kg per leg during the push-off region of stance phase. The net metabolic cost of walking with the active exoskeleton (3.28 ± 0.10 W/kg) was an 11 ± 4 % (p = 0.019) reduction compared to the cost of walking without the exoskeleton (3.71 ± 0.14 W/kg). Wearing the ankle exoskeleton significantly reduced the mean positive power of the ankle joint by 0.033 ± 0.006 W/kg (p = 0.007), the knee joint by 0.042 ± 0.015 W/kg (p = 0.020), and the hip joint by 0.034 ± 0.009 W/kg (p = 0.006). This study shows that the ankle exoskeleton does not exclusively reduce positive mechanical power at the ankle joint, but also mitigates positive power at the knee and hip. Furthermore, the active ankle exoskeleton did not simply replace biological ankle function in walking, but rather augmented the total (biological + exoskeletal) ankle moment and power. This study underscores the need for comprehensive models of human-exoskeleton interaction and global optimization methods for the discovery of new control strategies that optimize the physiological impact of leg exoskeletons.

A model to evaluate 100-year energy mix scenarios to facilitate deep decarbonization in the southeastern United States

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

Adkisson, Mary A.; Qualls, A. L.

The Southeast United States consumes approximately one billion megawatt-hours of electricity annually; roughly two-thirds from carbon dioxide (CO 2) emitting sources. The balance is produced by non-CO 2 emitting sources: nuclear power, hydroelectric power, and other renewables. Approximately 40% of the total CO 2 emissions come from the electric grid. The CO 2 emitting sources, coal, natural gas, and petroleum, produce approximately 372 million metric tons of CO 2 annually. The rest is divided between the transportation sector (36%), the industrial sector (20%), the residential sector (3%), and the commercial sector (2%). An Energy Mix Modeling Analysis (EMMA) tool wasmore » developed to evaluate 100-year energy mix strategies to reduce CO 2 emissions in the southeast. Current energy sector data was gathered and used to establish a 2016 reference baseline. The spreadsheet-based calculation runs 100-year scenarios based on current nuclear plant expiration dates, assumed electrical demand changes from the grid, assumed renewable power increases and efficiency gains, and assumed rates of reducing coal generation and deployment of new nuclear reactors. Within the model, natural gas electrical generation is calculated to meet any demand not met by other sources. Thus, natural gas is viewed as a transitional energy source that produces less CO 2 than coal until non-CO 2 emitting sources can be brought online. The annual production of CO 2 and spent nuclear fuel and the natural gas consumed are calculated and summed. A progression of eight preliminary scenarios show that nuclear power can substantially reduce or eliminate demand for natural gas within 100 years if it is added at a rate of only 1000 MWe per year. Any increases in renewable energy or efficiency gains can offset the need for nuclear power. However, using nuclear power to reduce CO 2 will result in significantly more spent fuel. More efficient advanced reactors can only marginally reduce the amount of spent fuel generated in the next 100 years if they are assumed to be available beginning around 2040. Thus closing the nuclear fuel cycle to reduce nuclear spent fuel inventories should be considered. Future work includes the incorporation of economic features into the model and the extension of the evaluation to the industrial sector. It will also be necessary to identify suitable sites for additional reactors.« less

High-efficiency photovoltaic technology including thermoelectric generation

NASA Astrophysics Data System (ADS)

Fisac, Miguel; Villasevil, Francesc X.; López, Antonio M.

2014-04-01

Nowadays, photovoltaic solar energy is a clean and reliable source for producing electric power. Most photovoltaic systems have been designed and built up for use in applications with low power requirements. The efficiency of solar cells is quite low, obtaining best results in monocrystalline silicon structures, with an efficiency of about 18%. When temperature rises, photovoltaic cell efficiency decreases, given that the short-circuit current is slightly increased, and the open-circuit voltage, fill factor and power output are reduced. To ensure that this does not affect performance, this paper describes how to interconnect photovoltaic and thermoelectric technology into a single structure. The temperature gradient in the solar panel is used to supply thermoelectric cells, which generate electricity, achieving a positive contribution to the total balance of the complete system.

Process development and exergy cost sensitivity analysis of a hybrid molten carbonate fuel cell power plant and carbon dioxide capturing process

NASA Astrophysics Data System (ADS)

Mehrpooya, Mehdi; Ansarinasab, Hojat; Moftakhari Sharifzadeh, Mohammad Mehdi; Rosen, Marc A.

2017-10-01

An integrated power plant with a net electrical power output of 3.71 × 105 kW is developed and investigated. The electrical efficiency of the process is found to be 60.1%. The process includes three main sub-systems: molten carbonate fuel cell system, heat recovery section and cryogenic carbon dioxide capturing process. Conventional and advanced exergoeconomic methods are used for analyzing the process. Advanced exergoeconomic analysis is a comprehensive evaluation tool which combines an exergetic approach with economic analysis procedures. With this method, investment and exergy destruction costs of the process components are divided into endogenous/exogenous and avoidable/unavoidable parts. Results of the conventional exergoeconomic analyses demonstrate that the combustion chamber has the largest exergy destruction rate (182 MW) and cost rate (13,100 /h). Also, the total process cost rate can be decreased by reducing the cost rate of the fuel cell and improving the efficiency of the combustion chamber and heat recovery steam generator. Based on the total avoidable endogenous cost rate, the priority for modification is the heat recovery steam generator, a compressor and a turbine of the power plant, in rank order. A sensitivity analysis is done to investigate the exergoeconomic factor parameters through changing the effective parameter variations.

Particle and Power Exhaust in EAST

NASA Astrophysics Data System (ADS)

Wang, Liang; Ding, Fang; Yu, Yaowei; Gan, Kaifu; Liang, Yunfeng; Xu, Guosheng; Xiao, Bingjia; Sun, Youwen; Luo, Guangnan; Gong, Xianzu; Hu, Jiansheng; Li, Jiangang; Wan, Baonian; Maingi, Rajesh; Guo, Houyang; Garofalo, Andrea; EAST Team

2017-10-01

A total power injection up to 0.3GJ has been achieved in EAST long pulse USN operation with ITER-like water-cooling W-monoblock divertor, which has steady-state power exhaust capability of 10 MWm-2. The peak temperature of W target saturated at t = 12 s to the value T 500oC and a heat flux 3MWm-2was maintained. Great efforts to reduce heat flux and accommodate particle exhaust simultaneously have been made towards long pulse of 102s time scale. By exploiting the observation of Pfirsch-Schlüter flow direction in the SOL, the Bt direction with Bx ∇B away from the W divertor (more particles favor outer target in USN) was adopted along with optimizing the strike point location near the pumping slot, to facilitate particle and impurity exhaust with the top cryo-pump. By tailoring the 3D divertor footprint through edge magnetic topology change, the heat load was dispersed widely and thus peak heat flux and W sputtering was well controlled. Active feedback control of total radiative power with neon seeding was achieved within frad = 17-35%, exhibiting further potential for heat flux reduction with divertor and edge radiation. Other heat flux handling techniques, including quasi snowflake configuration, will also be presented.

Comparative studies on the constituents, antioxidant and anticancer activities of extracts from different varieties of corn silk.

PubMed

Tian, Jingge; Chen, Haixia; Chen, Shuhan; Xing, Lisha; Wang, Yanwei; Wang, Jia

2013-10-01

The purpose of this study was to analyze the influence of varieties on the constituents, antioxidant and anticancer activities of corn silk. The contents of total phenolic and flavonoids and individual flavonoids in six corn silk varieties (Denghai6702, Delinong988, Tunyu808, Zhongdan909, Liangyu208, Jingke968) were comparatively analyzed by colourimetric methods, high performance liquid chromatography (HPLC) methods and antioxidant activities were assessed using a panel of in vitro assays, including 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical-scavenging activity assay, the inhibitory effects on lipid peroxidation (MDA) assay and ferric reducing/antioxidant power (FRAP) assay, and the cytotoxicity against human prostatic carcinoma cells PC3 and breast carcinoma cells MDA-MB-231 and MCF7 were also evaluated. Results showed that Zhongdan909 exhibited the highest total phenolic content while Tunyu808 had the highest flavonoid content among the six species. Zhongdan909 showed the highest DPPH radical scavenging activity, the highest inhibitory effect on lipid peroxidation and the strongest cytotoxicity against breast carcinoma cells MCF7, while Tunyu808 exhibited the highest reducing power. There were good relationships between the total phenolic and flavonoid contents and antioxidant activities (r > 0.78) and the cytotoxicity against breast carcinoma cells MCF7 (r > 0.79). This study suggested that corn silk could be potentially used as a readily accessible source of natural antioxidants and formononetin was one of the main antioxidant constituents in corn silk.

Phytochemical and antimicrobial activities of Himalayan Cordyceps sinensis (Berk.) Sacc.

PubMed

Mamta; Mehrotra, Shubhi; Amitabh; Kirar, Vandana; Vats, Praveen; Nandi, Shoma Paul; Negi, P S; Misra, Kshipra

2015-01-01

This study evaluated the phytochemical and antimicrobial activities and also quantified bioactive nucleoside using high performance thin layer chromatography (HPTLC) of five extracts of Indian Himalayan Cordyceps sinensis prepared with different solvents employing accelerated solvent extraction (ASE) technique. The phytochemical potential of these extracts was quantified in terms of total phenolic and total flavonoid content while antioxidant activities were determined by 1,1-diphenyl-2-pycryl-hydrazyl (DPPH) and 2,2 -azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and ferric-reducing antioxidant power (FRAP) assays. Total reducing power (TRP) was determined by converting iron (III) into iron (II) reduction assay. CS(50%Alc) (15.1 ± 0.67mg/g of dry extract) and CS(100%Alc) (19.3 ± 0.33 mg/g of dry extract) showed highest phenolic and flavonoid content, respectively while CS(Aq) extract showed maximum antioxidant activity and the highest concentration of the three nucleosides (adenine 12.8 ± 0.49 mg/g, adenosine 0.36 ± 0.28 mg/g and uracil 0.14 ± 0.36 mg/g of dry extract) determined by HPTLC. The evaluation of extracts for antimicrobial activity against gram-negative and gram-positive bacterial strains showed CS(25%Alc), CS(75%Alc) and CS(100%Alc) extract to be more effective against E. coli, P. aerugenosa and B. subtilis giving 9, 7 and 6.5 mm of zone of inhibition (ZOI) in 93.75, 93.75 and 45 μg concentration, respectively, whereas CS(Aq) extract showed minimal inhibition against these.

Development of a hybrid battery system for an implantable biomedical device, especially a defibrillator/cardioverter (ICD)

NASA Astrophysics Data System (ADS)

Drews, Jürgen; Wolf, R.; Fehrmann, G.; Staub, R.

An implantable defibrillator battery has to provide pulse power capabilities as well as high energy density. Low self-discharge rates are mandatory and a way to check the remaining available capacity is necessary. These requirements are accomplished by a system consisting of a lithium/manganese dioxide 6 V battery, plus a lithium/iodine-cell. The use of a high rate 6 V double-cell design in combination with a high energy density cell reduces the total volume required by the power source within an implantable defibrillator. The design features and performance data of the hybrid system are described.

Asymptotically zero power charge-recycling bus architecture for battery-operated ultrahigh data rate ULSI's

NASA Astrophysics Data System (ADS)

Yamauchi, Hiroyuki; Akamatsu, Hironori; Fujita, Tsutomu

1995-04-01

An asymptotically zero power charge recycling bus (CRB) architecture, featuring virtual stacking of the individual bus-capacitance into a series configuration between supply voltage and ground, has been proposed. This CRB architecture makes it possible to reduce not only each bus-swing but also a total equivalent bus-capacitance of the ultramultibit buses running in parallel. The voltage swing of each bus is given by the recycled charge-supplying from the upper adjacent bus capacitance, instead of the power line. The dramatical power reduction was verified by the simulated and measured data. According to these data, the ultrahigh data rate of 25.6 Gb/s can be achieved while maintaining the power dissipation to be less than 100 mW, which corresponds to less than 10% that of the previously reported 0.9 V suppressed bus-swing scheme, at V(sub cc) = 3.6 V for the bus width of 512 b with the bus-capacitance of 14 pF per bit operating at 50 MHz.

Bubble Entropy: An Entropy Almost Free of Parameters.

PubMed

Manis, George; Aktaruzzaman, Md; Sassi, Roberto

2017-11-01

Objective : A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy . Bubble Entropy is based on permutation entropy, where the vectors in the embedding space are ranked. We use the bubble sort algorithm for the ordering procedure and count instead the number of swaps performed for each vector. Doing so, we create a more coarse-grained distribution and then compute the entropy of this distribution. Results: Experimental results with both real and synthetic HRV signals showed that bubble entropy presents remarkable stability and exhibits increased descriptive and discriminating power compared to all other definitions, including the most popular ones. Conclusion: The definition proposed is almost free of parameters. The most common ones are the scale factor r and the embedding dimension m . In our definition, the scale factor is totally eliminated and the importance of m is significantly reduced. The proposed method presents increased stability and discriminating power. Significance: After the extensive use of some entropy measures in physiological signals, typical values for their parameters have been suggested, or at least, widely used. However, the parameters are still there, application and dataset dependent, influencing the computed value and affecting the descriptive power. Reducing their significance or eliminating them alleviates the problem, decoupling the method from the data and the application, and eliminating subjective factors. Objective : A critical point in any definition of entropy is the selection of the parameters employed to obtain an estimate in practice. We propose a new definition of entropy aiming to reduce the significance of this selection. Methods: We call the new definition Bubble Entropy . Bubble Entropy is based on permutation entropy, where the vectors in the embedding space are ranked. We use the bubble sort algorithm for the ordering procedure and count instead the number of swaps performed for each vector. Doing so, we create a more coarse-grained distribution and then compute the entropy of this distribution. Results: Experimental results with both real and synthetic HRV signals showed that bubble entropy presents remarkable stability and exhibits increased descriptive and discriminating power compared to all other definitions, including the most popular ones. Conclusion: The definition proposed is almost free of parameters. The most common ones are the scale factor r and the embedding dimension m . In our definition, the scale factor is totally eliminated and the importance of m is significantly reduced. The proposed method presents increased stability and discriminating power. Significance: After the extensive use of some entropy measures in physiological signals, typical values for their parameters have been suggested, or at least, widely used. However, the parameters are still there, application and dataset dependent, influencing the computed value and affecting the descriptive power. Reducing their significance or eliminating them alleviates the problem, decoupling the method from the data and the application, and eliminating subjective factors.

Reduction of CO2 emission by INCAM model in Malaysia biomass power plants during the year 2016.

PubMed

Amin, Nor Aishah Saidina; Talebian-Kiakalaieh, Amin

2018-03-01

As the world's second largest palm oil producer and exporter, Malaysia could capitalize on its oil palm biomass waste for power generation. The emission factors from this renewable energy source are far lower than that of fossil fuels. This study applies an integrated carbon accounting and mitigation (INCAM) model to calculate the amount of CO 2 emissions from two biomass thermal power plants. The CO 2 emissions released from biomass plants utilizing empty fruit bunch (EFB) and palm oil mill effluent (POME), as alternative fuels for powering steam and gas turbines, were determined using the INCAM model. Each section emitting CO 2 in the power plant, known as the carbon accounting center (CAC), was measured for its carbon profile (CP) and carbon index (CI). The carbon performance indicator (CPI) included electricity, fuel and water consumption, solid waste and waste-water generation. The carbon emission index (CEI) and carbon emission profile (CEP), based on the total monthly carbon production, were determined across the CPI. Various innovative strategies resulted in a 20%-90% reduction of CO 2 emissions. The implementation of reduction strategies significantly reduced the CO 2 emission levels. Based on the model, utilization of EFB and POME in the facilities could significantly reduce the CO 2 emissions and increase the potential for waste to energy initiatives. Copyright © 2017 Elsevier Ltd. All rights reserved.

A simplified, low power system for effective vessel sealing

NASA Astrophysics Data System (ADS)

Lyle, Allison B.; Kennedy, Jenifer S.; Schmaltz, Dale F.; Kennedy, Aaron S.

2015-03-01

The first bipolar vessel sealing system was developed nearly 15 years ago and has since become standard of care in surgery. These systems make use of radio frequency current that is delivered between bipolar graspers to permanently seal arteries, veins and tissue bundles. Conventional vessel sealing generators are based off traditional electrosurgery generator architecture and deliver high power (150-300 Watts) and high current using complex control and sense algorithms to adjust the output for vessel sealing applications. In recent years, a need for small-scale surgical vessel sealers has developed as surgeons strive to further reduce their footprint on patients. There are many technical challenges associated with miniaturization of vessel sealing devices including maintaining electrical isolation while delivering high current in a saline environment. Research into creating a small, 3mm diameter vessel sealer revealed that a highly simplified generator system could be used to achieve excellent results and subsequently a low power vessel sealing system was developed. This system delivers 25 Watts constant power while limiting voltage (<= Vrms) and current (<= Amps) until an impedance endpoint is achieved, eliminating the use of complicated control and sensing software. The result is optimized tissue effect, where high seal strength is maintained (> 360mmHg), but seal times (1.7 +/- 0.7s versus 4.1 +/- 0.7s), thermal spread (<1mm vs <=2mm) and total energy delivery are reduced, when compared to an existing high power system.

Refining boat electrofishing equipment to improve consistency and reduce harm to fish

USGS Publications Warehouse

Miranda, L.E.

2005-01-01

A major concern with electrofishing is the standardization of sampling equipment and methods, particularly when collections are used to monitor spatial and temporal changes in fish communities. Standardization can not only ensure that stock assessment is consistent - that is, the data collected over time and space have equal meaning and are not influenced by differences in gear or gear application - but also reduce injury by constraining power to ranges that are likely to immobilize fish but unlikely to harm them. Standardization of electrofishing equipment requires adjusting power output to keep constant the amount of power transferred to fish in diverse water conditions. In this study, the power level thresholds required to immobilize and injure fish under controlled laboratory conditions were identified for various size-species combinations and applied to establish power minima and maxima suitable for successful and safe boat electrofishing. The target settings identified allowed survival of 99.4% of the fish collected and held for 2-3 h during field trials; all the mortalities were small fish (???53 mm long). The standardization procedure described herein may be adapted to single boats or fleets and can promote consistency in electrofishing, although it does not completely avoid harm to fish. Because electrofishing is an active capture method applied to changing microenvironments, complete standardization and total avoidance of harm to individual fish are not feasible with present technology, but standardization of controllable variables is advisable.

Lift and moment coefficients expanded to the seventh power of frequency for oscillating rectangular wings in supersonic flow and applied to a specific flutter problem

NASA Technical Reports Server (NTRS)

Nelson, Herbert C; Rainey, Ruby A; Watkins, Charles E

1954-01-01

Linearized theory for compressible unsteady flow is used to derive the velocity potential and lift and moment coefficients in the form of oscillating rectangular wing moving at a constant supersonic speed. Closed expressions for the velocity potential and lift and moment coefficients associated with pitching and translation are given to seventh power of the frequency. These expressions extend the range of usefulness of NACA report 1028 in which similar expressions were derived to the third power of the frequency of oscillation. For example, at a Mach number of 10/9 the expansion of the potential to the third power is an accurate representation of the potential for values of the reduced frequency only up to about 0.08; whereas the expansion of the potential to the seventh power is an accurate representation for values of the reduced frequency up to about 0.2. The section and total lift and moment coefficients are discussed with the aid of several figures. In addition, flutter speeds obtained in the Mach number range from 10/9 to 10/6 for a rectangular wing of aspect ratio 4.53 by using section coefficients derived on the basis of three-dimensional flow are compared with flutter speeds for this wing obtained by using coefficients derived on the basis of two-dimensional flow.

Impact production of NO and reduced species

NASA Technical Reports Server (NTRS)

Zahnle, K.; Kasting, J.; Sleep, N.

1988-01-01

It has recently been suggested that a reported spike in seawater (87)Sr/(86)Sr at the K-T boundary is the signature of an impact-generated acid deluge. However, the amount of acid required is implausibly large. Some about 3 x 10 to the 15th power moles of Sr must be weathered from silicates to produce the inferred Sr spike. The amount of acid required is at least 100 and probably 1000 times greater. Production of 3 x 10 to the 18th power moles of NO is clearly untenable. The atmosphere presently contains only 1.4 x 10 to the 20th power moles of N-sub 2 and 3.8 x 10 to the 19th power moles of O sub 2 If the entire atmosphere were shocked to 2000 K and cooled within a second, the total NO produced would be about 3 x 10 to the 18th power moles. This is obviously unrealistic. A (still to short) cooling time of 10th to the 3rd power sec reduces NO production by an order of magnitude. In passing, we note that if the entire atmosphere had in fact been shocked to 2000 K, acid rain would have been the least of a dinosaur's problems. Acid rain as a mechanism poses poses other difficulties. Recently deposited carbonates would have been most susceptable to acid attack. The researchers' preferred explanation is simply increased continental erosion following ecological trauma, coupled with enchanced levels of CO-sub 2.

Economic assessment and energy model scenarios of municipal solid waste incineration and gas turbine hybrid dual-fueled cycles in Thailand

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

Udomsri, Seksan, E-mail: seksan.udomsri@energy.kth.s; Martin, Andrew R.; Fransson, Torsten H.

Finding environmentally benign methods related to sound municipal solid waste (MSW) management is of highest priority in Southeast Asia. It is very important to study new approaches which can reduce waste generation and simultaneously enhance energy recovery. One concrete example of particular significance is the concept of hybrid dual-fuel power plants featuring MSW and another high-quality fuel like natural gas. The hybrid dual-fuel cycles provide significantly higher electrical efficiencies than a composite of separate single-fuel power plant (standalone gas turbine combined cycle and MSW incineration). Although hybrid versions are of great importance for energy conversion from MSW, an economic assessmentmore » of these systems must be addressed for a realistic appraisal of these technologies. This paper aims to further examine an economic assessment and energy model analysis of different conversion technologies. Energy models are developed to further refine the expected potential of MSW incineration with regards to energy recovery and environmental issues. Results show that MSW incineration can play role for greenhouse gas reduction, energy recovery and waste management. In Bangkok, the electric power production via conventional incineration and hybrid power plants can cover 2.5% and 8% of total electricity consumption, respectively. The hybrid power plants have a relative short payback period (5 years) and can further reduce the CO{sub 2} levels by 3% in comparison with current thermal power plants.« less

Impact of active and break wind spells on the demand-supply balance in wind energy in India

NASA Astrophysics Data System (ADS)

Kulkarni, Sumeet; Deo, M. C.; Ghosh, Subimal

2018-02-01

With an installed capacity of over 19,000 MW, the wind power currently accounts for almost 70% of the total installed capacity among the renewable energy sector in India. The extraction of wind power mainly depends on prevailing meteorology which is strongly influenced by monsoon variability. The monsoon season is characterized by significant fluctuations in between periods of wet and dry spells. During the dry spells, the demand for power from agriculture and cooling equipment increases, whereas during the wet periods, such demand reduces, although, at the same time, the power supply increases because of strong westerly winds contributing to an enhanced production of wind energy. At this backdrop, we aim to assess the impact of intra-seasonal wind variability on the balance of energy supply and demand during monsoon seasons in India. Further, we explore the probable cause of wind variability by relating it to El Nino events. It is observed that the active and break phases in wind significantly impact the overall wind potential output. Although the dry spells are generally found to reduce the overall wind potential, their impact on the potential seems to have declined after the year 2000. The impact of meteorological changes on variations in wind power studied in this work should find applications typically in taking investment decisions on conventional generation facilities, like thermal, which are currently used to maintain the balance of power supply and demand.

Economic assessment and energy model scenarios of municipal solid waste incineration and gas turbine hybrid dual-fueled cycles in Thailand.

PubMed

Udomsri, Seksan; Martin, Andrew R; Fransson, Torsten H

2010-07-01

Finding environmentally benign methods related to sound municipal solid waste (MSW) management is of highest priority in Southeast Asia. It is very important to study new approaches which can reduce waste generation and simultaneously enhance energy recovery. One concrete example of particular significance is the concept of hybrid dual-fuel power plants featuring MSW and another high-quality fuel like natural gas. The hybrid dual-fuel cycles provide significantly higher electrical efficiencies than a composite of separate single-fuel power plant (standalone gas turbine combined cycle and MSW incineration). Although hybrid versions are of great importance for energy conversion from MSW, an economic assessment of these systems must be addressed for a realistic appraisal of these technologies. This paper aims to further examine an economic assessment and energy model analysis of different conversion technologies. Energy models are developed to further refine the expected potential of MSW incineration with regards to energy recovery and environmental issues. Results show that MSW incineration can play role for greenhouse gas reduction, energy recovery and waste management. In Bangkok, the electric power production via conventional incineration and hybrid power plants can cover 2.5% and 8% of total electricity consumption, respectively. The hybrid power plants have a relative short payback period (5 years) and can further reduce the CO(2) levels by 3% in comparison with current thermal power plants. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

LIFAC Demonstration at Richmond Power and Light Whitewater Valley Unit No. 2 Volume II: Project Performance and Economics

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

None, None

The C1ean Coal Technology (CCT) Program has been recognized in the National Energy Strategy as a major initiative whereby coal will be able to reach its full potential as a source of energy for the nation and the international marketplace. Attainment of this goal depends upon the development of highly efficient, environmentally sound, competitive coal utilization technologies responsive to diverse energy markets and varied consumer needs. The CCT Program is an effort jointly funded by government and industry whereby the most promising of the advanced coal-based technologies are being moved into the marketplace through demonstration. The CCT Program is beingmore » implemented through a total of five competitive solicitations. LIFAC North America, a joint venture partnership of ICF Kaiser Engineers, Inc., and Tampella Power Corporation, is currently demonstrating the LIFAC flue gas desulfurization technology developed by Tampella Power. This technology provides sulfur dioxide emission control for power plants, especially existing facilities with tight space limitations. Sulfur dioxide emissions are expected to be reduced by up to 85% by using limestone as a sorbent. The LIFAC technology is being demonstrated at Whitewater Valley Unit No. 2, a 60-MW coal-fired power plant owned and operated by Richmond Power and Light (RP&L) and located in Richmond, Indiana. The Whitewater plant consumes high-sulfur coals, with sulfur contents ranging from 2.0-2.9 $ZO. The project, co-funded by LIFAC North America and DOE, is being conducted with the participation of Richmond Power and Light, the State of Indiana, the Electric Power Research Institute (EPRI), and the Black Beauty Coal Company. The project has a total cost of $21.4 million and a duration of 48 months from the preliminary design phase through the testing program.« less

Lightweight Damage Tolerant, High-Temperature Radiators for Nuclear Power and Propulsion

NASA Technical Reports Server (NTRS)

Craven, Paul D.; SanSoucie, Michael P.

2015-01-01

NASA is increasingly emphasizing exploration to bodies beyond near-Earth orbit. New propulsion systems and new spacecraft are being built for these missions. As the target bodies get further out from Earth, high energy density systems, e.g., nuclear fusion, for propulsion and power will be advantageous. The mass and size of these systems, including supporting systems such as the heat exchange system, including thermal radiators, will need to be as small as possible. Conventional heat exchange systems are a significant portion of the total thermal management mass and size. Nuclear electric propulsion (NEP) is a promising option for high-speed, in-space travel due to the high energy density of nuclear fission power sources and efficient electric thrusters. Heat from the reactor is converted to power for use in propulsion or for system power. The heat not used in the power conversion is then radiated to space as shown in figure 1. Advanced power conversion technologies will require high operating temperatures and would benefit from lightweight radiator materials. Radiator performance dictates power output for nuclear electric propulsion systems. Pitch-based carbon fiber materials have the potential to offer significant improvements in operating temperature, thermal conductivity, and mass. These properties combine to allow significant decreases in the total mass of the radiators and significant increases in the operating temperature of the fins. A Center-funded project at NASA Marshall Space Flight Center has shown that high thermal conductivity, woven carbon fiber fins with no matrix material, can be used to dissipate waste heat from NEP systems and because of high specific power (kW/kg), will require less mass and possibly less total area than standard metal and composite radiator fins for radiating the same amount of heat. This project uses an innovative approach to reduce the mass and size required for the thermal radiators to the point that in-space NEP and power is enabled. High thermal conductivity carbon fibers are lightweight, damage tolerant, and can be heated to high temperature. Areal densities in the NASA set target range of 2 to 4 kg/m2 (for enabling NEP) are achieved and with specific powers (kW/kg) a factor of about 7 greater than conventional metal fins and about 1.5 greater than carbon composite fins. Figure 2 shows one fin under test. All tests were done under vacuum conditions.

Assessment of air quality benefits from the national pollution control policy of thermal power plants in China: A numerical simulation

NASA Astrophysics Data System (ADS)

Wang, Zhanshan; Pan, Libo; Li, Yunting; Zhang, Dawei; Ma, Jin; Sun, Feng; Xu, Wenshuai; Wang, Xingrun

2015-04-01

In 2010, an emission inventory of air pollutants in China was created using the Chinese Bulletin of the Environment, the INTEX-B program, the First National Pollution Source Census, the National Generator Set Manual, and domestic and international research studies. Two emission scenarios, the standard failed emission scenario (S1) and the standard successful emission scenario (S2), were constructed based upon the Instructions for the Preparation of Emission Standards for Air Pollutants from Thermal Power Plants (second draft). The Fifth-Generation NCAR/Penn State Mesoscale Model (MM5) and the U.S. EPA Models-3 Community Multiscale Air Quality (CMAQ) model were applied to China to study the air quality benefits from Emission Standards for Air Pollutants from Thermal Power Plants GB13223-2011. The performance of MM5 and CMAQ was evaluated with meteorological data from Global Surface Data from the National Climatic Data Center (NCDC) and the daily Air Pollution Index (API) reported by Chinese local governments. The results showed that the implementation of the new standards could reduce the concentration of air pollutants and acid deposition in China by varying degrees. The new standards could reduce NO2 pollution in China. By 2020, for the scenario S2, the area with an NO2 concentration higher than the second-level emission standard, and the average NO2 concentration in 31 selected provinces would be reduced by 55.2% and 24.3%, respectively. The new standards could further reduce the concentration of declining SO2 in China. By 2020, for S2, the area with an SO2 concentration higher than the second-level emission standard and the average SO2 concentration in the 31 selected provinces would be reduced by 40.0% and 31.6%, respectively. The new standards could also reduce PM2.5 pollution in China. By 2020, for S2, the area with a PM2.5 concentration higher than the second-level emission standard and the average concentration of PM2.5 in the 31 selected provinces would be reduced by 17.2% and 14.7%, respectively. The new standard could reduce nitrogen deposition pollution in China. By 2020, for S2, the area with a nitrogen deposition concentration >2.0 tons·km-2 and the total nitrogen deposition in China would be reduced by 28.6% and 16.8%, respectively. The new standards could reduce sulfur deposition pollution in China. By 2020, for S2, the area with a sulfur deposition >1.5 tons·km-2 and the total sulfur deposition in China would be reduced by 55.3% and 21.0%, respectively.

Effect of concentration temperature on some bioactive compounds and antioxidant proprieties of date syrup.

PubMed

Abbès, Fatma; Besbes, Souhail; Brahim, Bchir; Kchaou, Wissal; Attia, Hamadi; Blecker, Christophe

2013-08-01

The effect of the concentration temperature on the antioxidant activity, carotenoid and phenolic compounds of date syrup was investigated. Date juice was concentrated at 100  and at "60  in vacuum". After concentration, total phenolic, tannin, non-tannin, flavonoid and carotenoid content were determined spectrophotometrically and high-performance liquid chromatography was used for determination of 5-Hydroxymethyl-2-furfuraldehyde content. The antioxidant activity of date syrup was evaluated by various antioxidant methods including total antioxidant, 2,2-diphenyl-1-picrylhydrazyl free radical scavenging test, ferric reducing antioxidant power and β-carotene bleaching. All date syrups showed strong antioxidant activity accompanied by high total phenolic contents. Results showed that concentration at 100  significantly enhanced the antioxidant activities and total phenolic contents of date syrups compared to vacuum concentration at 60 . A good correlation between the antioxidant activity and total phenolic content and flavonoid was observed.

Total Phenolic, Phenolic Acid, Anthocyanin, Flavan-3-ol, and Flavonol Profiles and Antioxidant Properties of Pinto and Black Beans ( Phaseolus vulgaris L.) as Affected by Thermal Processing.

PubMed

Xu, Baojun; Chang, Sam K C

2009-06-10

The effects of boiling and steaming processes at atmospheric and high pressures on the phenolic components and antioxidant properties of pinto and black beans were investigated. In comparison to the original raw beans, all processing methods caused significant (p < 0.05) decreases in total phenolic content (TPC), total flavonoid content (TFC), condensed tannin content (CTC), monomeric anthocyanin content (MAC), DPPH free-radical scavenging activity (DPPH), ferric-reducing antioxidant power (FRAP), and oxygen radical absorbing capacity (ORAC) values in both pinto and black beans. Steaming processing resulted in a greater retention of TPC, DPPH, FRAP, and ORAC values than the boiling processes in both pinto and black beans. To further investigate how thermal processing affected phenolic compositions and to elucidate the contribution of individual phenolic compounds to antioxidant properties, phenolic acids, anthocyanins, flavan-3-ols, and flavonols were quantitatively analyzed by high-performance liquid chromatography (HPLC). All thermal processing significantly (p < 0.05) affected individual phenolic acids, anthocyanins, flavan-3-ols, and flavonols, significantly (p < 0.05) reduced total phenolic acid contents in both pinto and black beans and total flavonol contents in pinto beans, and dramatically reduced anthocyanin contents in black beans. Phenolic acids and flavonols may play important roles on the overall antioxidant activities of pinto beans, while anthocyanins, flavan-3-ols, and flavonols may play important roles on the overall antioxidant activities of black beans.

Variation in minerals, phenolics and antioxidant activity of peel and pulp of different varieties of peach (Prunus persica L.) fruit from Pakistan.

PubMed

Manzoor, Maleeha; Anwar, Farooq; Mahmood, Zahed; Rashid, Umer; Ashraf, Muhammad

2012-05-30

Peach (Prunus persica L.), being a potential source of bioactive compounds, has been demonstrated to have medicinal benefits. In this study variation of minerals and antioxidant characteristics (total phenolic contents, total flavonoid contents, reducing power, inhibition of peroxidation using linoleic acid system and DPPH free radical scavenging activity) between peel and pulp parts of different peach varieties, namely Golden, Shireen, and Shahpasand were investigated. The peel and pulp extracts, derived from the varieties analyzed, exhibited an appreciable amount of total phenolics (TP) and total flavonoids (TF), ranging from 1,209.3-1,354.5, 711.7-881.3 mg GAE/100 g and 599.7-785.5, 301.3-499.7 mg CE/100 g on a dry weight basis, respectively. Reducing power of peel and pulp extracts (12.5 mg/mL concentration) ranged from 2.57-2.77 and 1.54-1.99.The inhibition of linoleic acid peroxidation and DPPH scavenging activity of the extracts varied from 70.8-80.9% and 66.8-76.5% in peels, and 51.9-60.1% and 43.4-49.1% in pulps. The mineral analysis revealed that the content of K was highest in both parts of the peach fruit followed by Mg, Ca, Fe, Mn and Zn. The results of our present study indicate that peach peel had significantly higher levels of minerals, antioxidant capacity and phenolics than those of the pulp, suggesting the intake of unpeeled peach as a potential source of high-value components. The peach peel can be a useful as a viable source of natural antioxidants for functional foods and nutraceutical applications.

Investigation of key parameters for the development of reliable ITER baseline operation scenarios using CORSICA

NASA Astrophysics Data System (ADS)

Kim, S. H.; Casper, T. A.; Snipes, J. A.

2018-05-01

ITER will demonstrate the feasibility of burning plasma operation by operating DT plasmas in the ELMy H-mode regime with a high ratio of fusion power gain Q ~ 10. 15 MA ITER baseline operation scenario has been studied using CORSICA, focusing on the entry to burn, flat-top burning plasma operation and exit from burn. The burning plasma operation for about 400 s of the current flat-top was achieved in H-mode within the various engineering constraints imposed by the poloidal field coil and power supply systems. The target fusion gain (Q ~ 10) was achievable in the 15 MA ITER baseline operation with a moderate amount of the total auxiliary heating power (~50 MW). It has been observed that the tungsten (W) concentration needs to be maintained low level (n w/n e up to the order of 1.0  ×  10-5) to avoid the radiative collapse and uncontrolled early termination of the discharge. The dynamic evolution of the density can modify the H-mode access unless the applied auxiliary heating power is significantly higher than the H-mode threshold power. Several qualitative sensitivity studies have been performed to provide guidance for further optimizing the plasma operation and performance. Increasing the density profile peaking factor was quite effective in increasing the alpha particle self-heating power and fusion power multiplication factor. Varying the combination of auxiliary heating power has shown that the fusion power multiplication factor can be reduced along with the increase in the total auxiliary heating power. As the 15 MA ITER baseline operation scenario requires full capacity of the coil and power supply systems, the operation window for H-mode access and shape modification was narrow. The updated ITER baseline operation scenarios developed in this work will become a basis for further optimization studies necessary along with the improvement in understanding the burning plasma physics.

Hydropower assessment of Bolivia—A multisource satellite data and hydrologic modeling approach

USGS Publications Warehouse

Velpuri, Naga Manohar; Pervez, Shahriar; Cushing, W. Matthew

2016-11-28

This study produced a geospatial database for use in a decision support system by the Bolivian authorities to investigate further development and investment potentials in sustainable hydropower in Bolivia. The study assessed theoretical hydropower of all 1-kilometer (km) stream segments in the country using multisource satellite data and a hydrologic modeling approach. With the assessment covering the 2 million square kilometer (km2) region influencing Bolivia’s drainage network, the potential hydropower figures are based on theoretical yield assuming that the systems generating the power are 100 percent efficient. There are several factors to consider when determining the real-world or technical power potential of a hydropower system, and these factors can vary depending on local conditions. Since this assessment covers a large area, it was necessary to reduce these variables to the two that can be modeled consistently throughout the region, streamflow or discharge, and elevation drop or head. First, the Shuttle Radar Topography Mission high-resolution 30-meter (m) digital elevation model was used to identify stream segments with greater than 10 km2 of upstream drainage. We applied several preconditioning processes to the 30-m digital elevation model to reduce errors and improve the accuracy of stream delineation and head height estimation. A total of 316,500 1-km stream segments were identified and used in this study to assess the total theoretical hydropower potential of Bolivia. Precipitation observations from a total of 463 stations obtained from the Bolivian Servicio Nacional de Meteorología e Hidrología (Bolivian National Meteorology and Hydrology Service) and the Brazilian Agência Nacional de Águas (Brazilian National Water Agency) were used to validate six different gridded precipitation estimates for Bolivia obtained from various sources. Validation results indicated that gridded precipitation estimates from the Tropical Rainfall Measuring Mission (TRMM) reanalysis product (3B43) had the highest accuracies. The coarse-resolution (25-km) TRMM data were disaggregated to 5-km pixels using climatology information obtained from the Climate Hazards Group Infrared Precipitation with Stations dataset. About a 17-percent bias was observed in the disaggregated TRMM estimates, which was corrected using the station observations. The bias-corrected, disaggregated TRMM precipitation estimate was used to compute stream discharge using a regionalization approach. In regionalization approach, required homogeneous regions for Bolivia were derived from precipitation patterns and topographic characteristics using a k-means clustering approach. Using the discharge and head height estimates for each 1-km stream segment, we computed hydropower potential for 316,490 stream segments within Bolivia and that share borders with Bolivia. The total theoretical hydropower potential (TTHP) of these stream segments was found to be 212 gigawatts (GW). Out of this total, 77.4 GW was within protected areas where hydropower projects cannot be developed; hence, the remaining total theoretical hydropower in Bolivia (outside the protected areas) was estimated as 135 GW. Nearly 1,000 1-km stream segments, however, were within the boundaries of existing hydropower projects. The TTHP of these stream segments was nearly 1.4 GW, so the residual TTHP of the streams in Bolivia was estimated as 133 GW. Care should be exercised to understand and interpret the TTHP identified in this study because all the stream segments identified and assessed in this study cannot be harnessed to their full capacity; furthermore, factors such as required environmental flows, efficiency, economics, and feasibility need to be considered to better identify a more real-world hydropower potential. If environmental flow requirements of 20–40 percent are considered, the total theoretical power available reduces by 60–80 percent. In addition, a 0.72 efficiency factor further reduces the estimation by another 28 percent. This study provides the base theoretical hydropower potential for Bolivia, the next step is to identify optimal hydropower plant locations and factor in the principles to appraise a real-world power potential in Bolivia.

Mitigating an increase of specific power consumption in a cryogenic air separation unit at reduced oxygen production

NASA Astrophysics Data System (ADS)

Singla, Rohit; Chowdhury, Kanchan

2017-02-01

Specific power consumed in a Linde double column air separation unit (ASU) increases as the quantity of oxygen produced at a given purity is decreased due to the changes of system requirement or market demand. As the plant operates in part load condition, the specific power consumption (SPC) increases as the total power consumption remains the same. In order to mitigate the increase of SPC at lower oxygen production, the operating pressure of high pressure column (HPC) can be lowered by extending the low pressure column (LPC) by a few trays and adding a second reboiler. As the duty of second reboiler in LPC is increased, the recovery of oxygen decreases with a lowering of the HPC pressure. This results in mitigation of the increase of SPC of the plant. A Medium pressure ASU with dual reboiler that produces pressurised gaseous and liquid products of oxygen and nitrogen is simulated in Aspen Hysys 8.6®, a commercial process simulator to determine SPC at varying oxygen production. The effects of reduced pressure of air feed into the cold box on the size of heat exchangers (HX) are analysed. Operation strategy to obtain various oxygen production rates at varying demand is also proposed.

Food and processing residues in California: resource assessment and potential for power generation.

PubMed

Matteson, Gary C; Jenkins, B M

2007-11-01

The California agricultural industry produces more than 350 commodities with a combined yearly value in excess of $28 billion. The processing of many of these crops results in the production of residue streams, and the food processing industry faces increasing regulatory pressure to reduce environmental impacts and provide for sustainable management and use. Surveys of food and other processing and waste management sectors combined with published state data yield a total resource in excess of 4 million metric tons of dry matter, with nearly half of this likely to be available for utilization. About two-thirds of the available resource is produced as high-moisture residues that could support 134 MWe of power generation by anaerobic digestion and other conversion techniques. The other third is generated as low-moisture materials, many of which are already employed as fuel in direct combustion biomass power plants. The cost of energy conversion remains high for biochemical systems, with tipping or disposal fees of the order of $30-50Mg(-1) required to align power costs with current market prices. Identifying ways to reduce capital and operating costs of energy conversion, extending operating seasons to increase capacity factors through centralizing facilities, combining resource streams, and monetizing environmental benefits remain important goals for restructuring food and processing waste management in the state.

Broadband and scalable mobile satellite communication system for future access networks

NASA Astrophysics Data System (ADS)

Ohata, Kohei; Kobayashi, Kiyoshi; Nakahira, Katsuya; Ueba, Masazumi

2005-07-01

Due to the recent market trends, NTT has begun research into next generation satellite communication systems, such as broadband and scalable mobile communication systems. One service application objective is to provide broadband Internet access for transportation systems, temporal broadband access networks and telemetries to remote areas. While these are niche markets the total amount of capacity should be significant. We set a 1-Gb/s total transmission capacity as our goal. Our key concern is the system cost, which means that the system should be unified system with diversified services and not tailored for each application. As satellites account for a large portion of the total system cost, we set the target satellite size as a small, one-ton class dry mass with a 2-kW class payload power. In addition to the payload power and weight, the mobile satellite's frequency band is extremely limited. Therefore, we need to develop innovative technologies that will reduce the weight and maximize spectrum and power efficiency. Another challenge is the need for the system to handle up to 50 dB and a wide data rate range of other applications. This paper describes the key communication system technologies; the frequency reuse strategy, multiplexing scheme, resource allocation scheme, and QoS management algorithm to ensure excellent spectrum efficiency and support a variety of services and quality requirements in the mobile environment.

Detecting seasonal and cyclical trends in agricultural runoff water quality-hypothesis tests and block bootstrap power analysis.

PubMed

Uddameri, Venkatesh; Singaraju, Sreeram; Hernandez, E Annette

2018-02-21

Seasonal and cyclic trends in nutrient concentrations at four agricultural drainage ditches were assessed using a dataset generated from a multivariate, multiscale, multiyear water quality monitoring effort in the agriculturally dominant Lower Rio Grande Valley (LRGV) River Watershed in South Texas. An innovative bootstrap sampling-based power analysis procedure was developed to evaluate the ability of Mann-Whitney and Noether tests to discern trends and to guide future monitoring efforts. The Mann-Whitney U test was able to detect significant changes between summer and winter nutrient concentrations at sites with lower depths and unimpeded flows. Pollutant dilution, non-agricultural loadings, and in-channel flow structures (weirs) masked the effects of seasonality. The detection of cyclical trends using the Noether test was highest in the presence of vegetation mainly for total phosphorus and oxidized nitrogen (nitrite + nitrate) compared to dissolved phosphorus and reduced nitrogen (total Kjeldahl nitrogen-TKN). Prospective power analysis indicated that while increased monitoring can lead to higher statistical power, the effect size (i.e., the total number of trend sequences within a time-series) had a greater influence on the Noether test. Both Mann-Whitney and Noether tests provide complementary information on seasonal and cyclic behavior of pollutant concentrations and are affected by different processes. The results from these statistical tests when evaluated in the context of flow, vegetation, and in-channel hydraulic alterations can help guide future data collection and monitoring efforts. The study highlights the need for long-term monitoring of agricultural drainage ditches to properly discern seasonal and cyclical trends.

Phase-locked loop design with fast-digital-calibration charge pump

NASA Astrophysics Data System (ADS)

Wang, San-Fu; Hwang, Tsuen-Shiau; Wang, Jhen-Ji

2016-02-01

A fast-digital-calibration technique is proposed for reducing current mismatch in the charge pump (CP) of a phase-locked loop (PLL). The current mismatch in the CP generates fluctuations, which is transferred to the input of voltage-controlled oscillator (VCO). Therefore, the current mismatch increases the reference spur in the PLL. Improving current match of CP will reduce the reference spur and decrease the static phase offset of PLLs. Moreover, the settling time, ripple and power consumption of the PLL are also improved by the proposed technique. This study evaluated a 2.27-2.88 GHz frequency synthesiser fabricated in TSMC 0.18 μm CMOS 1.8 V process. The tuning range of proposed VCO is about 26%. By using the fast-digital-calibration technique, current mismatch is reduced to lower than 0.97%, and the operation range of the proposed CP is between 0.2 and 1.6 V. The proposed PLL has a total power consumption of 22.57 mW and a settling time of 10 μs or less.

Antioxidant and antimicrobial properties of phenolic rich fraction of Seabuckthorn (Hippophae rhamnoides L.) leaves in vitro.

PubMed

Yogendra Kumar, M S; Tirpude, R J; Maheshwari, D T; Bansal, Anju; Misra, Ksipra

2013-12-15

Phenolic rich fraction (PRF) from Seabuckthorn leaves was prepared by sequential fractionation. Total phenolic content of PRF estimated as gallic acid equivalent was found to be 319.33±7.02 mg/g of PRF. Its major constituents gallic acid, rutin, quercetin-3-galactoside, quercetin-3-glucoside, myricetin, quercetin, kaempferol and isorhamnetin, were found in the range of 1.551-196.89 mg/g of PRF as determined by RP-HPLC. Antioxidant activity of PRF evaluated using 2,2-diphenyl-2-picrylhydrazyl, superoxide and nitric oxide scavenging assays. Reducing power of PRF increased with increasing amount of PRF; the equation of reducing power (y) and amount of PRF (x) was y=8.004x (r(2)=0.99), indicating that reducing ability correlated well with amount of PRF. Antibacterial activity of PRF, tested against certain medically important bacterial species showed growth inhibiting effect against Escherichia coli, Salmonella typhi, Shigella dysenteriae, Streptococcus pneumoniae and Staphylococcus aureus. In conclusion, PRF has potent antioxidant and broad spectrum antibacterial properties. Copyright © 2013 Elsevier Ltd. All rights reserved.

Evaluation of in vitro antioxidant properties of methanol and aqueous extracts of Parkinsonia aculeata L. leaves.

PubMed

Sharma, Sonia; Vig, Adarsh Pal

2013-01-01

In the present study, methanol and aqueous extracts of Parkinsonia aculeata L. leaves were prepared and analyzed for phytochemical analysis and antioxidant potential in different in vitro assays. Antioxidant activity was studied using DPPH, CUPRAC, reducing power assay, deoxyribose degradation (site and nonsite specific), ferric reducing antioxidant potential (FRAP), ferric thiocyanate (FTC), thiobarbituric acid (TBA), and molybdate ion reduction, respectively. The total phenolic contents of the methanol and aqueous leaf extract were 39 mg GAE/g and 38 mg GAE/g, whereas flavonoid contents of these extracts were found to be 0.013 mg RE/g and 0.006 mg RE/g, respectively. From the two extracts, the methanol extract shows maximum inhibition (%) of 57.82%, 71.23%, 48.26%, 69.85%, and 52.78% in DPPH, nonsite- and site-specific, FTC, and TBA assays and absorbance of 0.669 and 0.241 in reducing power and CUPRAC assays at the highest concentration tested. UPLC analysis was done to determine the presence of various types of polyphenols present in plant extracts.

Evaluation of In Vitro Antioxidant Properties of Methanol and Aqueous Extracts of Parkinsonia aculeata L. Leaves

PubMed Central

Vig, Adarsh Pal

2013-01-01

In the present study, methanol and aqueous extracts of Parkinsonia aculeata L. leaves were prepared and analyzed for phytochemical analysis and antioxidant potential in different in vitro assays. Antioxidant activity was studied using DPPH, CUPRAC, reducing power assay, deoxyribose degradation (site and nonsite specific), ferric reducing antioxidant potential (FRAP), ferric thiocyanate (FTC), thiobarbituric acid (TBA), and molybdate ion reduction, respectively. The total phenolic contents of the methanol and aqueous leaf extract were 39 mg GAE/g and 38 mg GAE/g, whereas flavonoid contents of these extracts were found to be 0.013 mg RE/g and 0.006 mg RE/g, respectively. From the two extracts, the methanol extract shows maximum inhibition (%) of 57.82%, 71.23%, 48.26%, 69.85%, and 52.78% in DPPH, nonsite- and site-specific, FTC, and TBA assays and absorbance of 0.669 and 0.241 in reducing power and CUPRAC assays at the highest concentration tested. UPLC analysis was done to determine the presence of various types of polyphenols present in plant extracts. PMID:24348173

Alpha-Amylase Inhibition and Antioxidative Capacity of Some Antidiabetic Plants Used by the Traditional Healers in Southeastern Nigeria

PubMed Central

Oyedemi, Blessing O.; Ijeh, Ifeoma I.; Ohanyerem, Princemartins E.; Aiyegoro, Olayinka A.

2017-01-01

Oxidative stress plays a significant role in the pathogenesis of metabolic syndrome including diabetes mellitus (DM). The inhibition of alpha-amylase is an important therapeutic target in the regulation of postprandial increase of blood glucose in diabetic patients. The present study investigated the alpha-amylase inhibitory and antioxidant potential of selected herbal drugs used in the treatment of DM by the traditional healers in Isiala Mbano and Ikwuano regions of southeastern Nigeria. Antioxidant activity was evaluated in terms of free radical scavenging, reducing power, and total phenolic (TPC) and flavonoid content (TFC) in consonance with the TLC profiling. The results showed that methanol crude extracts from Anacardium occidentale (AO) and Ceiba pentandra (CP) recorded higher TPC and TFC, potent free radical scavenging, and efficient reducing power (RP) as compared with other plant samples. All the plant extracts exhibited a relative alpha-amylase inhibition apart from Strophanthus hispidus (SH) extract with a negative effect. We discovered a mild to weak correlation between alpha-amylase inhibition or antioxidative capacity and the total phenol or flavonoid content. At least in part, the results obtained in this work support the traditional use of certain plant species in the treatment of patients with DM. PMID:28367491

Variation of antioxidant activity and the levels of bioactive compounds in lipophilic and hydrophilic extracts from hot pepper (Capsicum spp.) cultivars.

PubMed

Bae, Haejin; Jayaprakasha, G K; Jifon, John; Patil, Bhimanagouda S

2012-10-15

Peppers (Capsicum spp.) are a rich source of diverse bioactive compounds with potential health-promoting properties. This study investigated the extraction efficiency of five solvents on antioxidant activities from cayenne (CA408 and Mesilla), jalapeño (Ixtapa) and serrano (Tuxtlas) pepper cultivars. Freeze-dried peppers were extracted using a Soxhlet extractor with five solvents: hexane, ethyl acetate, acetone, methanol, and methanol:water (80:20). The levels of specific bioactive compounds (phenolics, capsaicinoids, carotenoids and flavonoids) were determined by HPLC and antioxidant activities were assayed by three methods. For all pepper cultivars tested, hexane extracts had the highest levels of capsaicinoids and carotenoids, but methanol extracts had the maximum levels of flavonoids. Hexane extracts showed higher 2,2-diphenyl-1-pricrylhydrozyl (DPPH) radical-scavenging activity and higher reducing power, and acetone extracts (from Mesilla pepper) had a high reducing power. All pepper extracts, except hexane, were effective in preventing deoxyribose degradation, and the inhibition was increased by high concentrations of extracts. The results of the present study indicated that, among the different measures of antioxidant activity, DPPH radical-scavenging activity was strongly correlated with total bioactive compounds (capsaicinoids, carotenoids, flavonoids and total phenolics) in pepper cultivars. Copyright © 2012 Elsevier Ltd. All rights reserved.

Results of closed cycle MHD power generation tests with a helium-cesium working fluid

NASA Technical Reports Server (NTRS)

Sovie, R. J.

1977-01-01

The cross-sectional dimensions of the MHD channel in the NASA Lewis closed loop facility have been reduced to 3.8 x 11.4 cm. Tests were run in this channel using a helium-cesium working fluid at stagnation pressures of 1.6 x 10 to the 5th N/sq m, stagnation temperatures of 2000-2060 K and an entrance Mach number of 0.36. In these tests Faraday open circuit voltages of 200 V were measured which correspond to a Faraday field of 1750 V/m. Power generation tests were run for different groups of electrode configurations and channel lengths. Hall fields up to 1450 V/m were generated. Power extraction per electrode of 183 W and power densities of 1.7 MW/cu m have been obtained. A total power output of 2 kW was generated for tests with 14 electrodes. The power densities obtained in this channel represent a factor of 3 improvement over those reported for the m = 0.2 channel at the last EAM Symposium.

Sampling benthic macroinvertebrates in a large flood-plain river: Considerations of study design, sample size, and cost

USGS Publications Warehouse

Bartsch, L.A.; Richardson, W.B.; Naimo, T.J.

1998-01-01

Estimation of benthic macroinvertebrate populations over large spatial scales is difficult due to the high variability in abundance and the cost of sample processing and taxonomic analysis. To determine a cost-effective, statistically powerful sample design, we conducted an exploratory study of the spatial variation of benthic macroinvertebrates in a 37 km reach of the Upper Mississippi River. We sampled benthos at 36 sites within each of two strata, contiguous backwater and channel border. Three standard ponar (525 cm(2)) grab samples were obtained at each site ('Original Design'). Analysis of variance and sampling cost of strata-wide estimates for abundance of Oligochaeta, Chironomidae, and total invertebrates showed that only one ponar sample per site ('Reduced Design') yielded essentially the same abundance estimates as the Original Design, while reducing the overall cost by 63%. A posteriori statistical power analysis (alpha = 0.05, beta = 0.20) on the Reduced Design estimated that at least 18 sites per stratum were needed to detect differences in mean abundance between contiguous backwater and channel border areas for Oligochaeta, Chironomidae, and total invertebrates. Statistical power was nearly identical for the three taxonomic groups. The abundances of several taxa of concern (e.g., Hexagenia mayflies and Musculium fingernail clams) were too spatially variable to estimate power with our method. Resampling simulations indicated that to achieve adequate sampling precision for Oligochaeta, at least 36 sample sites per stratum would be required, whereas a sampling precision of 0.2 would not be attained with any sample size for Hexagenia in channel border areas, or Chironomidae and Musculium in both strata given the variance structure of the original samples. Community-wide diversity indices (Brillouin and 1-Simpsons) increased as sample area per site increased. The backwater area had higher diversity than the channel border area. The number of sampling sites required to sample benthic macroinvertebrates during our sampling period depended on the study objective and ranged from 18 to more than 40 sites per stratum. No single sampling regime would efficiently and adequately sample all components of the macroinvertebrate community.

Effect of Microwave-Assisted Extraction on the Phenolic Compounds and Antioxidant Capacity of Blackthorn Flowers.

PubMed

Lovrić, Vanja; Putnik, Predrag; Kovačević, Danijela Bursać; Jukić, Marijana; Dragović-Uzelac, Verica

2017-06-01

This research was undertaken to investigate the influence of extraction parameters during microwave-assisted extraction on total phenolic content, total flavonoids, total hydroxycinnamic acids and total flavonols of blackthorn flowers as well as to evaluate the antioxidant capacity by two different methods (2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity and ferric reducing antioxidant power assays). The investigated extraction parameters were: solvent type and volume fraction of alcohol in solvent (50 and 70% aqueous solutions of ethanol and methanol), extraction time (5, 15 and 25 min) and extraction temperature (40, 50 and 60 °C) controlled by microwave power of 100, 200 and 300 W. Multivariate analysis of variance (MANOVA) was used to evaluate the differences at a 95% confidence level (p≤0.05). The obtained results show that aqueous solution of ethanol was more appropriate solvent for extraction of phenolic compounds (total flavonoids, total hydroxycinnamic acids and total flavonols) than aqueous solution of methanol. The amount of phenolic compounds was higher in 70% aqueous solution of ethanol or methanol, while higher antioxidant capacity was observed in 50% aqueous solution of methanol. Higher temperature of extraction improved the amount of phenolic compounds and also antioxidant capacity determined by 2,2-diphenyl-1-picrylhydrazyl free radical scavenging capacity assay. Extensive duration of extraction (15- to 25-minute interval) has a significant effect only on the increase of total phenolic content, while specific phenolic compound content and antioxidant capacity were the highest when microwave extraction time of 5 min was applied.

Effects of hot-air and hybrid hot air-microwave drying on drying kinetics and textural quality of nectarine slices

NASA Astrophysics Data System (ADS)

Miraei Ashtiani, Seyed-Hassan; Sturm, Barbara; Nasirahmadi, Abozar

2018-04-01

Drying and physicochemical characteristics of nectarine slices were investigated using hot-air and hybrid hot air-microwave drying methods under fixed air temperature and air speed (50 °C and 0.5 m/s, respectively). Microwave power levels for the combined hot air-microwave method were 80, 160, 240, and 320 W. Drying kinetics were analyzed and compared using six mathematical models. For both drying methods the model with the best fitness in explaining the drying behavior was the Midilli-Kucuk model. The coefficient of determination ( R 2), root mean square error (RMSE) and reduced chi square ( χ 2) for this model have been obtained greater than 0.999 and less than 0.006 and 0.0001 for hybrid hot air-microwave drying while those values for hot-air drying were more than 0.999 and less than 0.003 and 0.0001, respectively. Results showed that the hybrid method reduced the drying time considerably and produced products with higher quality. The range of effective moisture diffusivity ( D eff ) of hybrid and hot-air drying was between 8.15 × 10-8 and 2.83 × 10-7 m2/s and 1.27 × 10-8 m2/s, respectively. The total color difference (ΔE) has also been obtained from 36.68 to 44.27 for hybrid method; however this value for hot-air drying was found 49.64. Although reduced microwave power output led to a lower drying rate, it reduced changes in product parameters i.e. total color change, surface roughness, shrinkage and microstructural change and increased hardness and water uptake.

B-vitamin Supplementation Mitigates Effects of Fine Particles on Cardiac Autonomic Dysfunction and Inflammation: A Pilot Human Intervention Trial

NASA Astrophysics Data System (ADS)

Zhong, Jia; Trevisi, Letizia; Urch, Bruce; Lin, Xinyi; Speck, Mary; Coull, Brent A.; Liss, Gary; Thompson, Aaron; Wu, Shaowei; Wilson, Ander; Koutrakis, Petros; Silverman, Frances; Gold, Diane R.; Baccarelli, Andrea A.

2017-04-01

Ambient fine particle (PM2.5) pollution triggers acute cardiovascular events. Individual-level preventions are proposed to complement regulation in reducing the global burden of PM2.5-induced cardiovascular diseases. We determine whether B vitamin supplementation mitigates PM2.5 effects on cardiac autonomic dysfunction and inflammation in a single-blind placebo-controlled crossover pilot trial. Ten healthy adults received two-hour controlled-exposure-experiment to sham under placebo, PM2.5 (250 μg/m3) under placebo, and PM2.5 (250 μg/m3) under B-vitamin supplementation (2.5 mg/d folic acid, 50 mg/d vitamin B6, and 1 mg/d vitamin B12), respectively. At pre-, post-, 24 h-post-exposure, we measured resting heart rate (HR) and heart rate variability (HRV) with electrocardiogram, and white blood cell (WBC) counts with hematology analyzer. Compared to sham, PM2.5 exposure increased HR (3.8 bpm, 95% CI: 0.3, 7.4; P = 0.04), total WBC count (11.5%, 95% CI: 0.3%, 24.0%; P = 0.04), lymphocyte count (12.9%, 95% CI: 4.4%, 22.1%; P = 0.005), and reduced low-frequency power (57.5%, 95% CI: 2.5%, 81.5%; P = 0.04). B-vitamin supplementation attenuated PM2.5 effect on HR by 150% (P = 0.003), low-frequency power by 90% (P = 0.01), total WBC count by 139% (P = 0.006), and lymphocyte count by 106% (P = 0.02). In healthy adults, two-hour PM2.5 exposure substantially increases HR, reduces HRV, and increases WBC. These effects are reduced by B vitamin supplementation.

Biochemical response of hybrid black poplar tissue culture (Populus × canadensis) on water stress.

PubMed

Popović, B M; Štajner, D; Ždero-Pavlović, R; Tari, I; Csiszár, J; Gallé, Á; Poór, P; Galović, V; Trudić, B; Orlović, S

2017-05-01

In this study, poplar tissue culture (hybrid black poplar, M1 genotype) was subjected to water stress influenced by polyethyleneglycol 6000 (100 and 200 mOsm PEG 6000). The aim of the research was to investigate the biochemical response of poplar tissue culture on water deficit regime. Antioxidant status was analyzed including antioxidant enzymes, superoxide-dismutase (SOD), catalase (CAT), guiacol-peroxidase (GPx), glutathione-peroxidase (GSH-Px), glutathione-reductase, reduced glutathione, total phenol content, Ferric reducing antioxidant power and DPPH radical antioxidant power. Polyphenol oxidase and phenylalanine-ammonium-lyase were determined as enzymatic markers of polyphenol metabolism. Among oxidative stress parameters lipid peroxidation, carbonyl-proteins, hydrogen-peroxide, reactive oxygen species, nitric-oxide and peroxynitrite were determined. Proline, proline-dehydrogenase and glycinebetaine were measured also as parameters of water stress. Cell viability is finally determined as a biological indicator of osmotic stress. It was found that water stress induced reactive oxygen and nitrogen species and lipid peroxidation in leaves of hybrid black poplar and reduced cell viability. Antioxidant enzymes including SOD, GPx, CAT and GSH-Px were induced but total phenol content and antioxidant capacity were reduced by PEG 6000 mediated osmotic stress. The highest biochemical response and adaptive reaction was the increase of proline and GB especially by 200 mOsm PEG. While long term molecular analysis will be necessary to fully address the poplar potentials for water stress adaptation, our results on hybrid black poplar suggest that glycine-betaine, proline and PDH enzyme might be the most important markers of poplar on water stress and that future efforts should be focused on these markers and strategies to enhance their concentration in poplar.

Enhanced reproducibility of L-mode plasma discharges via physics-model-based q-profile feedback control in DIII-D

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

Schuster, Eugenio J.; Wehner, William P.; Barton, Joseph E.

Recent experiments on DIII-D demonstrate the potential of physics-model-based q-profile control to improve reproducibility of plasma discharges. A combined feed forward + feedback control scheme is employed to optimize the current ramp-up phase by consistently achieving target q profiles (Target 1: q min = 1.3,q 95 = 4:4; Target 2: q min = 1.65,q 95 = 5.0; Target 3: q min = 2.1,q 95 = 6:2) at prescribed times during the plasma formation phase (Target 1: t = 1.5 s; Target 2: t = 1:3 s; Target 3: t = 1.0 s). At the core of the control scheme ismore » a nonlinear, first-principles-driven, physics-based, control-oriented model of the plasma dynamics valid for low confinement (L-mode) scenarios. To prevent undesired L-H transitions, a constraint on the maximum allowable total auxiliary power is imposed in addition to the maximum powers for the individual heating and current-drive sources. Experimental results are presented to demonstrate the effectiveness of the combined feed forward + feedback control scheme to consistently achieve the desired target profiles at the predefined times. Here, these results also show how the addition of feedback control significantly improves upon the feed forward only control solution by reducing the matching error and also how the feedback controller is able to reduce the matching error as the constraint on the maximum allowable total auxiliary power is relaxed while keeping the plasma in L-mode.« less

Mushrooms as Possible Antioxidant and Antimicrobial Agents

PubMed Central

Kosanić, Marijana; Ranković, Branislav; Dašić, Marko

2012-01-01

The aim of the study is to examine in-vitro antioxidant and antimicrobial activity of the acetonic and methanolic extracts of the mushrooms Boletus aestivalis, Boletus edulis and Leccinum carpini. Antioxidant activity was evaluated by using free radical scavenging activity and reducing power. In addition, total content of phenol and flavonoid in extracts were determined as pyrocatechol equivalent, and as rutin equivalent, respectively. As a result of the study acetonic extracts from Boletus edulis was more powerful antioxidant activity with IC50 value of 4.72 μg/mL which was similar or greater than the standard antioxidants, ascorbic acid (IC50 = 4.22 μg/mL), BHA (IC50 = 6.42 μg/mL) and α-tocopherol (IC50 = 62.43 μg/mL). Moreover, the tested extracts had effective reducing power. A significant relationship between total phenolic and flavonoid contents and their antioxidative activities was significantly observed. The antimicrobial activity of each extract was estimated by determination of the minimum inhibitory concentration by using microdilution plate method against five species of bacteria and five species of fungi. Generally, the tested mushroom extracts had relatively strong antimicrobial activity against the tested microorganisms. The minimum inhibitory concentration for both extracts related to the tested bacteria and fungi were 1.25 - 10 mg/ mL. The present study shows that tested mushroom species demonstrated a strong antioxidant and antimicrobial activity. It suggests that mushroom may be used as good sources of natural antioxidants and for pharmaceutical purposes in treating of various deseases. PMID:24250542

Ultrasound-Assisted Extraction of Cannabinoids from Cannabis Sativa L. Optimized by Response Surface Methodology.

PubMed

Agarwal, Charu; Máthé, Katalin; Hofmann, Tamás; Csóka, Levente

2018-03-01

Ultrasonication was used to extract bioactive compounds from Cannabis sativa L. such as polyphenols, flavonoids, and cannabinoids. The influence of 3 independent factors (time, input power, and methanol concentration) was evaluated on the extraction of total phenols (TPC), flavonoids (TF), ferric reducing ability of plasma (FRAP) and the overall yield. A face-centered central composite design was used for statistical modelling of the response data, followed by regression and analysis of variance in order to determine the significance of the model and factors. Both the solvent composition and the time significantly affected the extraction while the sonication power had no significant impact on the responses. The response predictions obtained at optimum extraction conditions of 15 min time, 130 W power, and 80% methanol were 314.822 mg GAE/g DW of TPC, 28.173 mg QE/g DW of TF, 18.79 mM AAE/g DW of FRAP, and 10.86% of yield. A good correlation was observed between the predicted and experimental values of the responses, which validated the mathematical model. On comparing the ultrasonic process with the control extraction, noticeably higher values were obtained for each of the responses. Additionally, ultrasound considerably improved the extraction of cannabinoids present in Cannabis. Low frequency ultrasound was employed to extract bioactive compounds from the inflorescence part of Cannabis. The responses evaluated were-total phenols, flavonoids, ferric reducing assay and yield. The solvent composition and time significantly influenced the extraction process. Appreciably higher extraction of cannabinoids was achieved on sonication against control. © 2018 Institute of Food Technologists®.

Enhanced reproducibility of L-mode plasma discharges via physics-model-based q-profile feedback control in DIII-D

DOE PAGES

Schuster, Eugenio J.; Wehner, William P.; Barton, Joseph E.; ...

2017-08-09

Recent experiments on DIII-D demonstrate the potential of physics-model-based q-profile control to improve reproducibility of plasma discharges. A combined feed forward + feedback control scheme is employed to optimize the current ramp-up phase by consistently achieving target q profiles (Target 1: q min = 1.3,q 95 = 4:4; Target 2: q min = 1.65,q 95 = 5.0; Target 3: q min = 2.1,q 95 = 6:2) at prescribed times during the plasma formation phase (Target 1: t = 1.5 s; Target 2: t = 1:3 s; Target 3: t = 1.0 s). At the core of the control scheme ismore » a nonlinear, first-principles-driven, physics-based, control-oriented model of the plasma dynamics valid for low confinement (L-mode) scenarios. To prevent undesired L-H transitions, a constraint on the maximum allowable total auxiliary power is imposed in addition to the maximum powers for the individual heating and current-drive sources. Experimental results are presented to demonstrate the effectiveness of the combined feed forward + feedback control scheme to consistently achieve the desired target profiles at the predefined times. Here, these results also show how the addition of feedback control significantly improves upon the feed forward only control solution by reducing the matching error and also how the feedback controller is able to reduce the matching error as the constraint on the maximum allowable total auxiliary power is relaxed while keeping the plasma in L-mode.« less

Influence of measurement error on Maxwell's demon

NASA Astrophysics Data System (ADS)

Sørdal, Vegard; Bergli, Joakim; Galperin, Y. M.

2017-06-01

In any general cycle of measurement, feedback, and erasure, the measurement will reduce the entropy of the system when information about the state is obtained, while erasure, according to Landauer's principle, is accompanied by a corresponding increase in entropy due to the compression of logical and physical phase space. The total process can in principle be fully reversible. A measurement error reduces the information obtained and the entropy decrease in the system. The erasure still gives the same increase in entropy, and the total process is irreversible. Another consequence of measurement error is that a bad feedback is applied, which further increases the entropy production if the proper protocol adapted to the expected error rate is not applied. We consider the effect of measurement error on a realistic single-electron box Szilard engine, and we find the optimal protocol for the cycle as a function of the desired power P and error ɛ .

Storage quality of walnut oil containing lycopene during accelerated oxidation.

PubMed

Xie, Chaonan; Ma, Zheng Feei; Li, Fang; Zhang, Hongxia; Kong, Lingming; Yang, Zhipan; Xie, Weifeng

2018-04-01

The purpose of investigation was to assess the effect of lycopene on the peroxide value, acid value, fatty acids, total phenolic content and ferric-reducing antioxidant power of walnut oil. Walnut oil was extracted from Xinjiang walnut variety using cold pressing method. Our study reported that after 45 days of accelerated oxidation at 60 °C (Schaal oven test), 0.005% lycopene exhibited the greatest antioxidant effect than other addition levels of lycopene. Therefore, under ambient storage conditions, the shelf-life of walnut oil could be extended up to 16 months by 0.005% lycopene. Moreover, 0.005% lycopene added to walnut oil had a significantly higher content of saturated fatty acid, unsaturated fatty acid, total phenol, reducing ability of the polar and non-polar components than the blank sample (walnut oil without any addition of lycopene). In conclusion, lycopene improved the quality of walnut oil because of its antioxidant effect against lipid oxidation.

A Low-Pressure Oxygen Storage System for Oxygen Supply in Low-Resource Settings.

PubMed

Rassool, Roger P; Sobott, Bryn A; Peake, David J; Mutetire, Bagayana S; Moschovis, Peter P; Black, Jim Fp

2017-12-01

Widespread access to medical oxygen would reduce global pneumonia mortality. Oxygen concentrators are one proposed solution, but they have limitations, in particular vulnerability to electricity fluctuations and failure during blackouts. The low-pressure oxygen storage system addresses these limitations in low-resource settings. This study reports testing of the system in Melbourne, Australia, and nonclinical field testing in Mbarara, Uganda. The system included a power-conditioning unit, a standard oxygen concentrator, and an oxygen store. In Melbourne, pressure and flows were monitored during cycles of filling/emptying, with forced voltage fluctuations. The bladders were tested by increasing pressure until they ruptured. In Mbarara, the system was tested by accelerated cycles of filling/emptying and then run on grid power for 30 d. The low-pressure oxygen storage system performed well, including sustaining a pressure approximately twice the standard working pressure before rupture of the outer bag. Flow of 1.2 L/min was continuously maintained to a simulated patient during 30 d on grid power, despite power failures totaling 2.9% of the total time, with durations of 1-176 min (mean 36.2, median 18.5). The low-pressure oxygen storage system was robust and durable, with accelerated testing equivalent to at least 2 y of operation revealing no visible signs of imminent failure. Despite power cuts, the system continuously provided oxygen, equivalent to the treatment of one child, for 30 d under typical power conditions for sub-Saharan Africa. The low-pressure oxygen storage system is ready for clinical field trials. Copyright © 2017 by Daedalus Enterprises.

Electrified Automotive Powertrain Architecture Using Composite DC–DC Converters

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

Chen, Hua; Kim, Hyeokjin; Erickson, Robert

In a hybrid or electric vehicle powertrain, a boost dc-dc converter enables reduction of the size of the electric machine and optimization of the battery system. Design of the powertrain boost converter is challenging because the converter must be rated at high peak power, while efficiency at medium-to-light load is critical for the vehicle system performance. By addressing only some of the loss mechanisms, previously proposed efficiency improvement approaches offer limited improvements in size, cost, and efficiency tradeoffs. This article shows how all dominant loss mechanisms in automotive powertrain applications can be mitigated using a new boost composite converter approach.more » In the composite dc-dc architecture, the loss mechanisms associated with indirect power conversion are addressed explicitly, resulting in fundamental efficiency improvements over wide ranges of operating conditions. Several composite converter topologies are presented and compared to state-of-the-art boost converter technologies. It is found that the selected boost composite converter results in a decrease in the total loss by a factor of 2-4 for typical drive cycles. Furthermore, the total system capacitor power rating and energy rating are substantially reduced, which implies potentials for significant reductions in system size and cost.« less

Electrified Automotive Powertrain Architecture Using Composite DC–DC Converters

DOE PAGES

Chen, Hua; Kim, Hyeokjin; Erickson, Robert; ...

2017-01-01

In a hybrid or electric vehicle powertrain, a boost dc-dc converter enables reduction of the size of the electric machine and optimization of the battery system. Design of the powertrain boost converter is challenging because the converter must be rated at high peak power, while efficiency at medium-to-light load is critical for the vehicle system performance. By addressing only some of the loss mechanisms, previously proposed efficiency improvement approaches offer limited improvements in size, cost, and efficiency tradeoffs. This article shows how all dominant loss mechanisms in automotive powertrain applications can be mitigated using a new boost composite converter approach.more » In the composite dc-dc architecture, the loss mechanisms associated with indirect power conversion are addressed explicitly, resulting in fundamental efficiency improvements over wide ranges of operating conditions. Several composite converter topologies are presented and compared to state-of-the-art boost converter technologies. It is found that the selected boost composite converter results in a decrease in the total loss by a factor of 2-4 for typical drive cycles. Furthermore, the total system capacitor power rating and energy rating are substantially reduced, which implies potentials for significant reductions in system size and cost.« less

Robust Transceiver Design for Multiuser MIMO Downlink with Channel Uncertainties

NASA Astrophysics Data System (ADS)

Miao, Wei; Li, Yunzhou; Chen, Xiang; Zhou, Shidong; Wang, Jing

This letter addresses the problem of robust transceiver design for the multiuser multiple-input-multiple-output (MIMO) downlink where the channel state information at the base station (BS) is imperfect. A stochastic approach which minimizes the expectation of the total mean square error (MSE) of the downlink conditioned on the channel estimates under a total transmit power constraint is adopted. The iterative algorithm reported in [2] is improved to handle the proposed robust optimization problem. Simulation results show that our proposed robust scheme effectively reduces the performance loss due to channel uncertainties and outperforms existing methods, especially when the channel errors of the users are different.

Efficient dual-wavelength laser at 946 and 1064 nm with compactly combined Nd:YAG and Nd:YVO4 crystals

NASA Astrophysics Data System (ADS)

Cho, C. Y.; Chang, C. C.; Chen, Y. F.

2013-04-01

We originally employ a compact combination of a Nd:YAG crystal and a Nd:YVO4 crystal to develop an efficient dual-wavelength laser operating at 946 and 1064 nm. We exploit a short Nd:YAG crystal to generate 946 nm laser by reducing the reabsorption loss and a follow-up Nd:YVO4 crystal to generate a 1064 nm laser by absorbing the residual pump light. The output power ratio between the 946 and 1064 nm emissions can be flexibly adjusted from 0.3 to 0.9 by varying the separation between the two output couplers. At an incident pump power of 17 W, the total output power is generally higher than 5.2 W, with an overall optical-to-optical efficiency greater than 30%.

A parametric study of the microwave plasma-assisted combustion of premixed ethylene/air mixtures

NASA Astrophysics Data System (ADS)

Fuh, Che A.; Wu, Wei; Wang, Chuji

2017-11-01

A parametric study of microwave argon plasma assisted combustion (PAC) of premixed ethylene/air mixtures was carried out using visual imaging, optical emission spectroscopy and cavity ringdown spectroscopy as diagnostic tools. The parameters investigated included the plasma feed gas flow rate, the plasma power, the fuel equivalence ratio and the total flow rate of the fuel/air mixture. The combustion enhancement effects were characterized by the minimum ignition power, the flame length and the fuel efficiency of the combustor. It was found that: (1) increasing the plasma feed gas flow rate resulted in a decrease in the flame length, an increase in the minimum ignition power for near stoichiometric fuel equivalence ratios and a corresponding decrease in the minimum ignition power for ultra-lean and rich fuel equivalence ratios; (2) at a constant plasma power, increasing the total flow rate of the ethylene/air mixture from 1.0 slm to 1.5 slm resulted in an increase in the flame length and a reduction in the fuel efficiency; (3) increasing the plasma power resulted in a slight increase in flame length as well as improved fuel efficiency with fewer C2(d) and CH(A) radicals present downstream of the flame; (4) increasing the fuel equivalence ratio caused an increase in flame length but at a reduced fuel efficiency when plasma power was kept constant; and (5) the ground state OH(X) number density was on the order of 1015 molecules/cm3 and was observed to drop downstream along the propagation axis of the flame at all parameters investigated. Results suggest that each of the parameters independently influences the PAC processes.

Solar tower enhanced natural draft dry cooling tower

NASA Astrophysics Data System (ADS)

Yang, Huiqiang; Xu, Yan; Acosta-Iborra, Alberto; Santana, Domingo

2017-06-01

Concentrating Solar Power (CSP) plants are located in desert areas where the Direct Normal Irradiance (DNI) value is very high. Since water resource is scarcely available, mechanical draft cooing technology is commonly used, with power consumption of mechanical fans being approximately 2% of the total power generated. Today, there is only one solar power plant (Khi Solar One in South Africa) uses a condenser installed in a Natural Draft Cooling (NDC) tower that avoids the windage loss of water occurring in wet cooling towers. Although, Khi Solar One is a cavity receiver power tower, the receivers can be hung onto the NDC tower. This paper looks at a novel integration of a NDC tower into an external molten salt receiver of a solar power plant, which is one of a largest commercial molten salt tower in China, with 100MWe power capacity. In this configuration study, the NDC tower surrounds the concrete tower of the receiver concentrically. In this way, the receiver concrete tower is the central support of the NDC tower, which consists of cable networks that are fixed to the concrete tower and suspended at a certain height over the floor. The cable networks support the shell of the NDC tower. To perform a preliminary analysis of the behavior of this novel configuration, two cases of numerical simulation in three dimensional (3D) models have been solved using the commercial Computational Fluid Dynamics (CFD) code, ANSYS Fluent 6.3. The results show that the integration of the NDC tower into an external central receiver tower is feasible. Additionally, the total heat transfer rate is not reduced but slightly increases when the molten salt receiver is in operation because of the additional natural draft induced by the high temperature of the receiver.

Total Phenolic and Flavonoid Contents of Aqueous Extract of Stinging Nettle and In Vitro Antiproliferative Effect on Hela and BT-474 Cell Lines.

PubMed

Fattahi, Sadegh; Zabihi, Ebrahim; Abedian, Zeinab; Pourbagher, Roghayeh; Motevalizadeh Ardekani, Ali; Mostafazadeh, Amrollah; Akhavan-Niaki, Haleh

2014-01-01

Phenolic compounds including flavonoids and phenolic acids are plants secondary metabolites. Due to their ability to act as antioxidant agents, there is a growing interest to use those components in traditional medicine for cancer prevention or treatment. The aim of this study was to measure the amounts of total phenolics and flavonoids as well as anti-proliferative effect of aqueous extract of Stinging nettle on BT-474 and Hela cell lines. The amounts of phenolics content and total flavonoids were determined by folin ciocalteu and aluminium chloride methods, respectively. The free radical scavenging activity was measured by using diphenyl - picrylhydrazyl (DPPH). The reducing power of the extract was measured in the presence of potassium hexacyanoferrate and its antiproliferative activity was assessed on BT-474 and Hela cell lines using MTT assay. Total phenolic content was 322.941± 11.811 mg gallic acid/g extract. Total flavonoid content was 133.916±12.006 mg Catechin/g. The IC50 of DPPH radical was 1.2 mg/ ml and the reducing power was 218.9± 15.582 μg ascorbic acid/ g. Cell viability of BT-474 cells decreased to less than half of the control (no added extract) at the presence of 3 mg/ ml extract while no significant changes were detected for Hela cells at similar conditions. There was no significant difference in the percentage of surviving cells between consecutive days (day 1, 2 and 3) for both BT-474 and Hela cells (P>0.05). Although the relatively high amount of phenolic and flavonoid contents of the aqueous extract make this plant a promising candidate for diseases treatment; however, there is not a direct relationship between the amounts of these antioxidant components and the efficiency in in vitro cancer treatment.

Total Phenolic and Flavonoid Contents of Aqueous Extract of Stinging Nettle and In Vitro Antiproliferative Effect on Hela and BT-474 Cell Lines

PubMed Central

Fattahi, Sadegh; Zabihi, Ebrahim; Abedian, Zeinab; Pourbagher, Roghayeh; Motevalizadeh Ardekani, Ali; Mostafazadeh, Amrollah; Akhavan-Niaki, Haleh

2014-01-01

Phenolic compounds including flavonoids and phenolic acids are plants secondary metabolites. Due to their ability to act as antioxidant agents, there is a growing interest to use those components in traditional medicine for cancer prevention or treatment. The aim of this study was to measure the amounts of total phenolics and flavonoids as well as anti-proliferative effect of aqueous extract of Stinging nettle on BT-474 and Hela cell lines. The amounts of phenolics content and total flavonoids were determined by folin ciocalteu and aluminium chloride methods, respectively. The free radical scavenging activity was measured by using diphenyl - picrylhydrazyl (DPPH). The reducing power of the extract was measured in the presence of potassium hexacyanoferrate and its antiproliferative activity was assessed on BT-474 and Hela cell lines using MTT assay. Total phenolic content was 322.941± 11.811 mg gallic acid/g extract. Total flavonoid content was 133.916±12.006 mg Catechin/g. The IC50 of DPPH radical was 1.2 mg/ ml and the reducing power was 218.9± 15.582 μg ascorbic acid/ g. Cell viability of BT-474 cells decreased to less than half of the control (no added extract) at the presence of 3 mg/ ml extract while no significant changes were detected for Hela cells at similar conditions. There was no significant difference in the percentage of surviving cells between consecutive days (day 1, 2 and 3) for both BT-474 and Hela cells (P>0.05). Although the relatively high amount of phenolic and flavonoid contents of the aqueous extract make this plant a promising candidate for diseases treatment; however, there is not a direct relationship between the amounts of these antioxidant components and the efficiency in in vitro cancer treatment. PMID:25035860

Antioxidant Activity of Three Honey Samples in relation with Their Biochemical Components

PubMed Central

Rahaman, Norul Liza A.; Adnan, Nur Ardawati; Eddie Tan, Ti Tjih

2013-01-01

The antioxidant activities based on the free radical scavenging, reducing power, and bleaching inhibition were investigated for the three commonly used honeys in Malaysia, namely, tualang, gelam, and acacia honey. The antioxidant capacity of the honey samples was correlated with their biochemical constituents such as total phenol, total flavonoid content, and total water-soluble vitamins (vitamin B1, B2, B3, B9, B12, and vitamin C). The total flavonoid content of honey samples was strongly correlated with the three antioxidative processes (r = 0.9276–0.9910). In contrast, the total water-soluble vitamins was found to be well correlated with the free radical scavenging activity (r = 0.8226). Vitamin B3 was likely to be in the highest concentration, which covered for 69–80% of the total vitamin content. A number of five phenolic acids, three flavonoids, and two organic acids had also been detected from the honey samples using UPLC-MS/MS, without sugar-removal procedure. PMID:24027653

A solar photovoltaic power system for use in Antarctica

NASA Astrophysics Data System (ADS)

Kohout, Lisa L.; Merolla, Anthony; Colozza, Anthony

1993-12-01

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys, and provided a six-person field team with electrical power for personal computers and printers, lab equipment, lighting, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering a total of 1.5 kWe peak power, three lead-acid gel battery modules supplying 2.4 kWh, and an electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for ease of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both an environmental and cost standpoint, is interested in the use of alternate forms of energy, such as solar power. Such a power system also will provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

A solar photovoltaic power system for use in Antarctica

NASA Technical Reports Server (NTRS)

Kohout, Lisa L.; Merolla, Anthony; Colozza, Anthony

1993-01-01

A solar photovoltaic power system was designed and built at the NASA Lewis Research Center as part of the NASA/NSF Antarctic Space Analog Program. The system was installed at a remote field camp at Lake Hoare in the Dry Valleys, and provided a six-person field team with electrical power for personal computers and printers, lab equipment, lighting, and a small microwave oven. The system consists of three silicon photovoltaic sub-arrays delivering a total of 1.5 kWe peak power, three lead-acid gel battery modules supplying 2.4 kWh, and an electrical distribution system which delivers 120 Vac and 12 Vdc to the user. The system was modularized for ease of deployment and operation. Previously the camp has been powered by diesel generators, which have proven to be both noisy and polluting. The NSF, in an effort to reduce their dependence on diesel fuel from both an environmental and cost standpoint, is interested in the use of alternate forms of energy, such as solar power. Such a power system also will provide NASA with important data on system level deployment and operation in a remote location by a minimally trained crew, as well as validate initial integration concepts.

DC-DC Type High-Frequency Link DC for Improved Power Quality of Cascaded Multilevel Inverter

NASA Astrophysics Data System (ADS)

Sadikin, Muhammad; Senjyu, Tomonobu; Yona, Atsushi

2013-06-01

Multilevel inverters are emerging as a new breed of power converter options for power system applications. Recent advances in power switching devices enabled the suitability of multilevel inverters for high voltage and high power applications because they are connecting several devices in series without the need of component matching. Usually, a transformerless battery energy storage system, based on a cascaded multilevel inverter, is used as a measure for voltage and frequency deviations. System can be reduced in size, weight, and cost of energy storage system. High-frequency link circuit topology is advantageous in realizing compact and light-weight power converters for uninterruptible power supply systems, new energy systems using photovoltaic-cells, fuel-cells and so on. This paper presents a DC-DC type high-frequency link DC (HFLDC) cascaded multilevel inverter. Each converter cell is implemented a control strategy for two H-bridge inverters that are controlled with the same multicarrier pulse width modulation (PWM) technique. The proposed cascaded multilevel inverter generates lower voltage total harmonic distortion (THD) in comparison with conventional cascaded multilevel inverter. Digital simulations are carried out using PSCAD/EMTDC to validate the performance of the proposed cascaded multilevel inverter.

PAH emissions from coal combustion and waste incineration.

PubMed

Hsu, Wei Ting; Liu, Mei Chen; Hung, Pao Chen; Chang, Shu Hao; Chang, Moo Been

2016-11-15

The characteristics of PAHs that are emitted by a municipal waste incinerator (MWI) and coal-fired power plant are examined via intensive sampling. Results of flue gas sampling reveal the potential for PAH formation within the selective catalytic reduction (SCR) system of a coal-fired power plant. In the large-scale MWI, the removal efficiency of PAHs achieved with the pilot-scaled catalytic filter (CF) exceeds that achieved by activated carbon injection with a bag filter (ACI+BF) owing to the effective destruction of gas-phase contaminants by a catalyst. A significantly lower PAH concentration (1640ng/g) was measured in fly ash from a CF module than from an ACI+BF system (5650ng/g). Replacing the ACI+BF system with CF technology would significantly reduce the discharge factor (including emission and fly ash) of PAHs from 251.6 to 77.8mg/ton-waste. The emission factors of PAHs that are obtained using ACI+BF and the CF system in the MWI are 8.05 and 7.13mg/ton, respectively. However, the emission factor of MWI is significantly higher than that of coal-fired power plant (1.56mg/ton). From the perspective of total environmental management to reduce PAH emissions, replacing the original ACI+BF process with a CF system is expected to reduce environmental impact thereof. Copyright © 2016 Elsevier B.V. All rights reserved.

Laser absorption, power transfer, and radiation symmetry during the first shock of inertial confinement fusion gas-filled hohlraum experiments

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

Pak, A.; Dewald, E. L.; Landen, O. L.

2015-12-15

Temporally resolved measurements of the hohlraum radiation flux asymmetry incident onto a bismuth coated surrogate capsule have been made over the first two nanoseconds of ignition relevant laser pulses. Specifically, we study the P2 asymmetry of the incoming flux as a function of cone fraction, defined as the inner-to-total laser beam power ratio, for a variety of hohlraums with different scales and gas fills. This work was performed to understand the relevance of recent experiments, conducted in new reduced-scale neopentane gas filled hohlraums, to full scale helium filled ignition targets. Experimental measurements, matched by 3D view factor calculations, are usedmore » to infer differences in symmetry, relative beam absorption, and cross beam energy transfer (CBET), employing an analytic model. Despite differences in hohlraum dimensions and gas fill, as well as in laser beam pointing and power, we find that laser absorption, CBET, and the cone fraction, at which a symmetric flux is achieved, are similar to within 25% between experiments conducted in the reduced and full scale hohlraums. This work demonstrates a close surrogacy in the dynamics during the first shock between reduced-scale and full scale implosion experiments and is an important step in enabling the increased rate of study for physics associated with inertial confinement fusion.« less

Aircraft of the future

NASA Technical Reports Server (NTRS)

Yeger, S.

1985-01-01

Some basic problems connected with attempts to increase the size and capacity of transport aircraft are discussed. According to the square-cubic law, the increase in structural weight is proportional to the third power of the increase in the linear dimensions of the aircraft when geomettric similarity is maintained, while the surface area of the aircraft increases according to the second power. A consequence is that the fraction of useful weight will decrease as aircraft increase in size. However, in flying-wing designs in which the whole load on the wing is proportional to the distribution of lifting forces, the total bending moment on the wing will be sharply reduced, enabling lighter construction. Flying wings may have an ultimate capacity of 3000 passengers.

Upgrading the fuel-handling machine of the Novovoronezh nuclear power plant unit no. 5

NASA Astrophysics Data System (ADS)

Terekhov, D. V.; Dunaev, V. I.

2014-02-01

The calculation of safety parameters was carried out in the process of upgrading the fuel-handling machine (FHM) of the Novovoronezh nuclear power plant (NPP) unit no. 5 based on the results of quantitative safety analysis of nuclear fuel transfer operations using a dynamic logical-and-probabilistic model of the processing procedure. Specific engineering and design concepts that made it possible to reduce the probability of damaging the fuel assemblies (FAs) when performing various technological operations by an order of magnitude and introduce more flexible algorithms into the modernized FHM control system were developed. The results of pilot operation during two refueling campaigns prove that the total reactor shutdown time is lowered.

Bioactive compounds and antioxidant activity analysis of Malaysian pineapple cultivars

NASA Astrophysics Data System (ADS)

Chiet, Chong Hang; Zulkifli, Razauden Mohamed; Hidayat, Topik; Yaakob, Harisun

2014-03-01

Pineapple industry is one of the important agricultural sectors in Malaysia with 76 cultivars planted throughout the country. This study aims to generate useful nutritional information as well as evaluating antioxidant properties of different pineapple commercial cultivars in Malaysia. The bioactive compound content and antioxidant capacity of `Josapine', `Morris' and `Sarawak' pineapple (Ananas comosus) were studied. The pineapple varieties were collected at commercial maturity stage (20-40% yellowish of fruit peel) and the edible portion of the fruit was used as sample for evaluation. The bioactive compound of the fruit extracts were evaluated by total phenolic and tannin content assay while the antioxidant capacity was determined by ferric reducing antioxidant power (FRAP). From the results obtained, total phenolic and tannin content was highest for `Josapine' followed by `Morris' and `Sarawak'. With respect to FRAP, `Josapine' showed highest reducing capacity, followed by `Morris' and then `Sarawak' having the least value. The bioactive compounds content are positively correlated with the antioxidant capacities of the pineapple extracts. This result indicates that the total phenolics and tannin content present in the pineapples may contribute to the antioxidant capacity of the pineapples.

CO{sub 2} mitigation potential of efficient demand-side technologies: The case of Thailand

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

Shrestha, R.M.; Biswas, W.K.; Timilsina, G.R.

This study assesses the techno-economic potential of selected demand-side efficient appliances to mitigate CO{sub 2} emission from the power sector in Thailand under national, consumer, and utility perspectives. A key finding of this study is that about 5.5--7% of the total annual CO{sub 2} emission from the electricity sector of the country can be reduced during 1996--2011 from the national perspective.

TacSats for Surveillance, Verification and C3I

DTIC Science & Technology

1993-02-01

a single significant fraction of the L.V. payload satellite of an identical total mass. and will reduce, in proportion , the Assuming the availability...power limited proportional to gas pressure; F= frequency lightsats: of the applied RF field. - small ion thrusters for drag At resonance F=Fc, and the...thrusters ir also the collision frequency proportional to required. Full thrust control, over a 30% the operating gas pressure. to 120 % range of the design

Cryogenic reactant storage for lunar base regenerative fuel cells

NASA Technical Reports Server (NTRS)

Kohout, Lisa L.

1989-01-01

There are major advantages to be gained by integrating a cryogenic reactant storage system with a hydrogen-oxygen regenerative fuel cell (RFC) to provide on-site electrical power during the lunar night. Although applicable to any power system using hydrogen-oxygen RFC's for energy storage, cryogenic reactant storage offers a significant benefit whenever the sun/shade cycle and energy storage period approach hundreds of hours. For solar power installations on the moon, cryogenic reactant storage reduces overall specific mass and meteoroid vulnerability of the system. In addition, it offers synergistic benefits to on-site users, such as availability of primary fuel cell reactants for surface rover vehicles and cryogenic propellants for OTV's. The integration involves processing and storing the RFC reactant streams as cryogenic liquids rather than pressurized gases, so that reactant containment (tankage per unit mass of reactants) can be greatly reduced. Hydrogen-oxygen alkaline RFC's, GaAs photovoltaic (PV) arrays, and space cryogenic processing/refrigeration technologies are assumed to be available for the conceptual system design. Advantages are demonstrated by comparing the characteristics of two power system concepts: a conventional lunar surface PV/RFC power system using pressurized gas storage in SOA filament wound pressure vessels and, that same system with gas liquefaction and storage replacing the pressurized storage. Comparisons are made at 20 and 250 kWe. Although cryogenic storage adds a processing plant (drying and liquefaction) to the system plus 30 percent more solar array to provide processing power, the approximate order of magnitude reduction in tankage mass, confirmed by this analysis, results in a reduction in overall total system mass of approximately 50 percent.

ALTERED PHALANX FORCE DIRECTION DURING POWER GRIP FOLLOWING STROKE

PubMed Central

Enders, Leah R.

2015-01-01

Many stroke survivors with severe impairment can grasp only with a power grip. Yet, little knowledge is available on altered power grip after stroke, other than reduced power grip strength. This study characterized stroke survivors’ static power grip during 100% and 50% maximum grip. Each phalanx force’s angular deviation from the normal direction and its contribution to total normal force was compared for 11 stroke survivors and 11 age-matched controls. Muscle activities and skin coefficient of friction (COF) were additionally compared for another 20 stroke and 13 age-matched control subjects. The main finding was that stroke survivors gripped with a 34% greater phalanx force angular deviation of 19±2° compared to controls of 14±1° (p<.05). Stroke survivors’ phalanx force angular deviation was closer to the 23° threshold of slippage between the phalanx and grip surface, which may explain increased likelihood of object dropping in stroke survivors. In addition, this altered phalanx force direction decreases normal grip force by tilting the force vector, indicating a partial role of phalanx force angular deviation in reduced grip strength post stroke. Greater phalanx force angular deviation may biomechanically result from more severe underactivation of stroke survivors’ first dorsal interosseous (FDI) and extensor digitorum communis (EDC) muscles compared to their flexor digitorum superficialis (FDS) or somatosensory deficit. While stroke survivors’ maximum power grip strength was approximately half of the controls’, the distribution of their remaining strength over the fingers and phalanges did not differ, indicating evenly distributed grip force reduction over the entire hand. PMID:25795079

Long pulse acceleration of MeV class high power density negative H{sup −} ion beam for ITER

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

Umeda, N., E-mail: umeda.naotaka@jaea.go.jp; Kojima, A.; Kashiwagi, M.

2015-04-08

R and D of high power density negative ion beam acceleration has been carried out at MeV test facility in JAEA to realize ITER neutral beam accelerator. The main target is H{sup −} ion beam acceleration up to 1 MeV with 200 A/m{sup 2} for 60 s whose pulse length is the present facility limit. For long pulse acceleration at high power density, new extraction grid (EXG) has been developed with high cooling capability, which electron suppression magnet is placed under cooling channel similar to ITER. In addition, aperture size of electron suppression grid (ESG) is enlarged from 14 mmmore » to 16 mm to reduce direct interception on the ESG and emission of secondary electron which leads to high heat load on the upstream acceleration grid. By enlarging ESG aperture, beam current increased 10 % at high current beam and total acceleration grid heat load reduced from 13 % to 10 % of input power at long pulse beam. In addition, heat load by back stream positive ion into the EXG is measured for the first time and is estimated as 0.3 % of beam power, while heat load by back stream ion into the source chamber is estimated as 3.5 ~ 4.0 % of beam power. Beam acceleration up to 60 s which is the facility limit, has achieved at 683 keV, 100 A/m{sup 2} of negative ion beam, whose energy density increases two orders of magnitude since 2011.« less

Anti-Cataract Potential of Heliotropium indicum Linn on Galactose-Induced Cataract in Sprague-Dawley Rats.

PubMed

Kyei, Samuel; Koffuor, George A; Ramkissoon, Paul; Abu, Emmanuel K; Sarpong, Josephine F

2017-03-01

To evaluate the anti-cataract potential of an aqueous whole plant extract of Heliotropium indicum (HIE) on galactose-induced cataract in Sprague-Dawley rats. Cataract scores were recorded in 3-week-old Sprague-Dawley rats in which cataract was being induced by an oral administration of 1500 mgkg -1 galactose twice daily for 4 weeks, and concurrently being treated with 30, 100, or 300 mgkg -1 HIE daily over the induction period. Fasting blood glucose was monitored at weekly intervals. Changes in body weight as well as total lens protein, lens glutathione, and superoxide dismutase (SOD) were determined initially, and at the end of the experimental period. Crystalline lens weight-to-body-weight ratio was also determined for the various treatment groups at the end of the experimental period. Preliminary phytochemical screening, total antioxidant capacity, and reducing power assays were conducted on HIE. The 30 and 100 mgkg -1 HIE-treated rats recorded significantly lower (p ≤ 0.05-0.001) cataract scores (indicating very significant delays in cataractogenesis by the 3 rd and 4 th weeks of treatment) and blood glucose levels. Rats with delayed cataractogenesis also exhibited significant (p ≤ 0.05-0.001) weight gain, and reduction in lens weight. Total lens proteins glutathione and SOD levels in the crystalline lens were also significantly preserved (p ≤ 0.01-0.001). HIE showed substantial antioxidant capacity and reducing power. The aqueous whole plant extract of Heliotropium indicum delays cataractogenesis at an optimum dose of 30 mgkg -1 in Sprague-Dawley rats.

Effect of Pelargonium reniforme roots on alcohol-induced liver damage and oxidative stress.

PubMed

Adewusi, Emmanuel Adekanmi; Afolayan, Anthony Jide

2010-09-01

Ethnobotanical surveys conducted on Pelargonium reniforme Curtis (Geraniaceae) have shown that the aqueous root extracts are used to treat alcohol-induced liver damage. We evaluated the antioxidant properties of the extract and its effects on alcohol-induced hepatotoxicity using Wistar rats. Alcohol-induced hepatotoxicity studies were carried out by observing the effect of the aqueous root extract on some liver marker enzymes, bilirubin, and total protein after liver damage. The levels of some phenolic compounds were determined by standard methods. Also, the reducing power of the plant extract and its ability to scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH*) and 2,2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS*+) radicals were determined to evaluate its antioxidant activity. The results obtained show that the plant extract possessed significant antioxidant activity. It had a significant level of phenolic compounds, scavenged DPPH* and ABTS*+ radicals effectively, and demonstrated good reducing power. This may indicate that the plant contained compounds which can remove toxic metabolites following alcohol abuse. Serum analysis of animals treated with only ethanol showed a significant increase in the levels of liver marker enzymes and total and unconjugated bilirubin, while a significant decrease was observed in the levels of conjugated bilirubin and total proteins. Administration of the plant extract restored the levels of these markers to normal levels, and this indicates the ability of the plant extract to restore normal functioning of a damaged liver. The study shows that P. reniforme is a potential source of antioxidants and compounds which are useful in treating alcoholic liver damage.

Ultra high bypass Nacelle aerodynamics inlet flow-through high angle of attack distortion test

NASA Technical Reports Server (NTRS)

Larkin, Michael J.; Schweiger, Paul S.

1992-01-01

A flow-through inlet test program was conducted to evaluate inlet test methods and determine the impact of the fan on inlet separation when operating at large angles of attack. A total of 16 model configurations of approximately 1/6 scale were tested. A comparison of these flow-through results with powered data indicates the presence of the fan increased separation operation 3 degrees to 4 degrees over the flow through inlet. Rods and screens located at the fan face station, that redistribute the flow, achieved simulation of the powered-fan results for separation angle of attack. Concepts to reduce inlet distortion and increase angle of attack capability were also evaluated. Vortex generators located on the inlet surface increased inlet angle of attack capability up to 2 degrees and reduced inlet distortion in the separated region. Finally, a method of simulating the fan/inlet aerodynamic interaction using blockage sizing method has been defined. With this method, a static blockage device used with a flow-through model will approximate the same inlet onset of separation angle of attack and distortion pattern that would be obtained with an inlet model containing a powered fan.

Developing a Hybrid Solar/Wind Powered Drip Irrigation System for Dragon Fruit Yield

NASA Astrophysics Data System (ADS)

Widiastuti, I.; Wijayanto, D. S.

2017-03-01

Irrigation operations take a large amount of water and energy which impact to total costs of crop production. Development of an efficient irrigation supplying precise amount of water and conserving the use of energy can have benefits not only by reducing the operating costs but also by enhancing the farmland productivity. This article presents an irrigation method that promotes sustainable use of water and energy appropriate for a developing tropical country. It proposes a drip irrigation system supported by a combined solar-wind electric power generation system for efficient use of water in dragon fruit cultivation. The electric power generated is used to drive a water pump filling a storage tank for irrigating a 3000 m2 dragon fruit yield in Nguntoronadi, Wonogiri, Indonesia. In designing the irrigation system, the plant’s water requirement was identified based on the value of reference evapotranspiration of the area. A cost/benefit analysis was performed to evaluate the economic feasibility of the proposed scheme. The installation of this solar and wind drip irrigation helps provide sufficient quantity of water to each plant using renewable energy sources which reduce dependence on fossil fuel.

A Low Power Digital Accumulation Technique for Digital-Domain CMOS TDI Image Sensor.

PubMed

Yu, Changwei; Nie, Kaiming; Xu, Jiangtao; Gao, Jing

2016-09-23

In this paper, an accumulation technique suitable for digital domain CMOS time delay integration (TDI) image sensors is proposed to reduce power consumption without degrading the rate of imaging. In terms of the slight variations of quantization codes among different pixel exposures towards the same object, the pixel array is divided into two groups: one is for coarse quantization of high bits only, and the other one is for fine quantization of low bits. Then, the complete quantization codes are composed of both results from the coarse-and-fine quantization. The equivalent operation comparably reduces the total required bit numbers of the quantization. In the 0.18 µm CMOS process, two versions of 16-stage digital domain CMOS TDI image sensor chains based on a 10-bit successive approximate register (SAR) analog-to-digital converter (ADC), with and without the proposed technique, are designed. The simulation results show that the average power consumption of slices of the two versions are 6 . 47 × 10 - 8 J/line and 7 . 4 × 10 - 8 J/line, respectively. Meanwhile, the linearity of the two versions are 99.74% and 99.99%, respectively.

A Bayesian sequential design with adaptive randomization for 2-sided hypothesis test.

PubMed

Yu, Qingzhao; Zhu, Lin; Zhu, Han

2017-11-01

Bayesian sequential and adaptive randomization designs are gaining popularity in clinical trials thanks to their potentials to reduce the number of required participants and save resources. We propose a Bayesian sequential design with adaptive randomization rates so as to more efficiently attribute newly recruited patients to different treatment arms. In this paper, we consider 2-arm clinical trials. Patients are allocated to the 2 arms with a randomization rate to achieve minimum variance for the test statistic. Algorithms are presented to calculate the optimal randomization rate, critical values, and power for the proposed design. Sensitivity analysis is implemented to check the influence on design by changing the prior distributions. Simulation studies are applied to compare the proposed method and traditional methods in terms of power and actual sample sizes. Simulations show that, when total sample size is fixed, the proposed design can obtain greater power and/or cost smaller actual sample size than the traditional Bayesian sequential design. Finally, we apply the proposed method to a real data set and compare the results with the Bayesian sequential design without adaptive randomization in terms of sample sizes. The proposed method can further reduce required sample size. Copyright © 2017 John Wiley & Sons, Ltd.

Hydrodynamic effects of kinetic power extraction by in-stream tidal turbines

NASA Astrophysics Data System (ADS)

Polagye, Brian L.

The hydrodynamic effects of extracting kinetic power from tidal streams presents unique challenges to the development of in-stream tidal power. In-stream tidal turbines superficially resemble wind turbines and extract kinetic power from the ebb and flood of strong tidal currents. Extraction increases the resistance to flow, leading to changes in tidal range, transport, mixing, and the kinetic resource itself. These far-field changes have environmental, social, and economic implications that must be understood to develop the in-stream resource. This dissertation describes the development of a one-dimensional numerical channel model and its application to the study of these effects. The model is applied to determine the roles played by site geometry, network topology, tidal regime, and device dynamics. A comparison is also made between theoretical and modeled predictions for the maximum amount of power which could be extracted from a tidal energy site. The model is extended to a simulation of kinetic power extraction from Puget Sound, Washington. In general, extracting tidal energy will have a number of far-field effects, in proportion to the level of power extraction. At the theoretical limit, these effects can be very significant (e.g., 50% reduction in transport), but are predicted to be immeasurably small for pilot-scale projects. Depending on the specifics of the site, far-field effects may either augment or reduce the existing tidal regime. Changes to the tide, in particular, have significant spatial variability. Since tidal streams are generally subcritical, effects are felt throughout the estuary, not just at the site of extraction. The one dimensional numerical modeling is supported by a robust theory for predicting the performance characteristics of in-stream devices. The far-field effects of tidal power depend on the total power dissipated by turbines, rather than the power extracted. When the low-speed wake downstream of a turbine mixes with the free-stream, power is lost, such that the total power dissipated by the turbine is significantly greater than the power extracted. This dissertation concludes with a framework for three-dimensional numerical modeling of near-field extraction effects.

Reliable and Affordable Control Systems Active Combustor Pattern Factor Control

NASA Technical Reports Server (NTRS)

McCarty, Bob; Tomondi, Chris; McGinley, Ray

2004-01-01

Active, closed-loop control of combustor pattern factor is a cooperative effort between Honeywell (formerly AlliedSignal) Engines and Systems and the NASA Glenn Research Center to reduce emissions and turbine-stator vane temperature variations, thereby enhancing engine performance and life, and reducing direct operating costs. Total fuel flow supplied to the engine is established by the speed/power control, but the distribution to individual atomizers will be controlled by the Active Combustor Pattern Factor Control (ACPFC). This system consist of three major components: multiple, thin-film sensors located on the turbine-stator vanes; fuel-flow modulators for individual atomizers; and control logic and algorithms within the electronic control.

Development of dielectric barrier discharge for reducing microbial contamination in pepper (Piper nigrum) and sesame (Sesamum indicum Linn.) powder

NASA Astrophysics Data System (ADS)

Promping, J.; Prakongsil, P.; Picha, R.; Traikool, T.

2017-09-01

This research is designed to determine the efficacy of DBD plasma to reduce the microbial contamination of pepper and sesame powder. The AC high voltage power supply was used with voltages of up to 20 kV and the frequency of 5.5 kHz was applied to the DBD. The gap of DBD electrodes was set at 5 mm. In raw initial samples, the total aerobic count of pepper (Piper nigrum) was found at quite a high level at 5.40 × 105 CFU/g. Coliform bacteria was also found in both the sesame (Sesamum indicum Linn.) powder and pepper (Piper nigrum) powder. Both kinds of samples were treated with plasma for 2, 4, 6 and 10 minutes. Results indicated that plasma treatment at 2-10 minutes reduced the total aerobic count of pepper allowed to achieve the acceptable microbial level for spices. The plasma treatment times in this experiment were also effective in reducing faecal coliform bacteria in both pepper and sesame powders (MPN/g <3) as indicated in the standard. Plasma from dielectric barrier charge can reduce Staphylococcus epidermidis in sesame powder which was artificially contaminated with 3.50 × 102 CFU/g resulting in 0.15-0.5 log cycle reductions of microbial load.

Movement Demands and Metabolic Power Comparisons Between Elite and Subelite Australian Footballers.

PubMed

Johnston, Richard J; Watsford, Mark L; Austin, Damien J; Pine, Matthew J; Spurrs, Robert W

2015-10-01

This study examined the differences in movement demands and metabolic power output of elite and subelite Australian football (AF) players and quantified the movement profiles of a subelite AF competition. Movement variables were collected from AF players using Global Positioning System devices over 2 AF League (elite) and North East Australian Football League (NEAFL, subelite) seasons. A total of 500 files were collected from 37 elite and subelite nomadic AF players. NEAFL players covered 13,547 m at an average speed of 124.5 m·min(-1). Elite players performed more high-speed running (5.7-6.3%) and high acceleration and deceleration efforts (1.9-14.7%, p ≤ 0.05). The elite players had a higher mean metabolic power output (3.2%) and time spent at the very high power zone (15.9%, p ≤ 0.05). In contrast, elite players recorded a lower total match duration than the subelite players (4%, p ≤ 0.05). The contrasting amount of high-intensity activities performed by the 2 groups demonstrates the need to alter the training programs of subelite players to ensure they are capable of meeting the demands of elite football. The differences in match duration suggest that reducing subelite players' match time through increasing their rotations would assist the replication of movement profiles of elite players.

When the Test of Mediation is More Powerful than the Test of the Total Effect

PubMed Central

O'Rourke, Holly P.; MacKinnon, David P.

2014-01-01

Although previous research has studied power in mediation models, the extent to which the inclusion of a mediator will increase power has not been investigated. First, a study compared analytical power of the mediated effect to the total effect in a single mediator model to identify the situations in which the inclusion of one mediator increased statistical power. Results from the first study indicated that including a mediator increased statistical power in small samples with large coefficients and in large samples with small coefficients, and when coefficients were non-zero and equal across models. Next, a study identified conditions where power was greater for the test of the total mediated effect compared to the test of the total effect in the parallel two mediator model. Results indicated that including two mediators increased power in small samples with large coefficients and in large samples with small coefficients, the same pattern of results found in the first study. Finally, a study assessed analytical power for a sequential (three-path) two mediator model and compared power to detect the three-path mediated effect to power to detect both the test of the total effect and the test of the mediated effect for the single mediator model. Results indicated that the three-path mediated effect had more power than the mediated effect from the single mediator model and the test of the total effect. Practical implications of these results for researchers are then discussed. PMID:24903690

How effective is group feedback in encouraging occupants of an office building to reduce energy consumption?

NASA Astrophysics Data System (ADS)

Shah, Ushik D.

Lighting contributes to a high percentage of the total energy use in office buildings. The lack of financial incentive often dissuades office workers from trying to save electricity at their work place. This thesis aims at reducing the total power consumed by an office building by using persuasive technologies on the occupants to promote environmentally conscious and energy saving behavior. A three week field study was conducted by providing occupants of an office building feedback about their energy consumption along with messages to encourage them to save energy. Feedback was provided via television screens and flyers placed strategically at the study location, the fourth floor of the Knoy Hall of Technology, Purdue University, West Lafayette campus. The results obtained from the analysis of data showed no change in energy consumption post intervention. Group feedback thus proved to be ineffective in encouraging occupants of this office building to reduce their energy consumption. This thesis presents the findings of the study and discusses recommendations and future scope for similar studies.

Comparison of the Inhibition of Monoamine Oxidase and Butyrylcholinesterase Activities by Infusions from Green Tea and Some Citrus Peels

PubMed Central

Ademosun, Ayokunle O.

2014-01-01

This study sought to investigate the effect of infusions from green tea (Camellia sinensis) and some citrus peels [shaddock (Citrus maxima), grapefruit (Citrus paradisi), and orange (Citrus sinensis)] on key enzymes relevant to the management of neurodegenerative conditions [monoamine oxidase (MAO) and butyrylcholinesterase (BChE)]. The total phenol contents and antioxidant activities as typified by their 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals scavenging abilities, ferric reducing antioxidant properties, and Fe2+ chelating abilities were also investigated. Green tea had the highest total phenol (43.3 mg/g) and total flavonoid (16.4 mg/g) contents, when compared to orange [total phenol (19.6 mg/g), total flavonoid (6.5 mg/g)], shaddock [total phenol (16.3 mg/g), total flavonoid (5.2 mg/g)], and grapefruit [total phenol (17.7 mg/g), total flavonoid (5.9 mg/g)]. Orange (EC50 = 1.78 mg/mL) had the highest MAO inhibitory ability, while green tea had the least MAO inhibitory ability (EC50 = 2.56 mg/mL). Similarly, green tea had the least BChE inhibitory ability (EC50 = 5.43 mg/mL) when compared to the citrus peels' infusions. However, green tea infusions had the strongest highest ABTS radical scavenging ability, reducing power, and Fe2+ chelating ability. The inhibition of MAO and BChE activities by the green tea and citrus peels infusions could make them good dietary means for the prevention/management of neurodegenerative conditions. PMID:25243093

Optimal Power Allocation for Downstream xDSL With Per-Modem Total Power Constraints: Broadcast Channel Optimal Spectrum Balancing (BC-OSB)

NASA Astrophysics Data System (ADS)

Le Nir, Vincent; Moonen, Marc; Verlinden, Jan; Guenach, Mamoun

2009-02-01

Recently, the duality between Multiple Input Multiple Output (MIMO) Multiple Access Channels (MAC) and MIMO Broadcast Channels (BC) has been established under a total power constraint. The same set of rates for MAC can be achieved in BC exploiting the MAC-BC duality formulas while preserving the total power constraint. In this paper, we describe the BC optimal power allo- cation applying this duality in a downstream x-Digital Subscriber Lines (xDSL) context under a total power constraint for all modems over all tones. Then, a new algorithm called BC-Optimal Spectrum Balancing (BC-OSB) is devised for a more realistic power allocation under per-modem total power constraints. The capacity region of the primal BC problem under per-modem total power constraints is found by the dual optimization problem for the BC under per-modem total power constraints which can be rewritten as a dual optimization problem in the MAC by means of a precoder matrix based on the Lagrange multipliers. We show that the duality gap between the two problems is zero. The multi-user power allocation problem has been solved for interference channels and MAC using the OSB algorithm. In this paper we solve the problem of multi-user power allocation for the BC case using the OSB algorithm as well and we derive a computational efficient algorithm that will be referred to as BC-OSB. Simulation results are provided for two VDSL2 scenarios: the first one with Differential-Mode (DM) transmission only and the second one with both DM and Phantom- Mode (PM) transmissions.

A novel wireless power and data transmission AC to DC converter for an implantable device.

PubMed

Liu, Jhao-Yan; Tang, Kea-Tiong

2013-01-01

This article presents a novel AC to DC converter implemented by standard CMOS technology, applied for wireless power transmission. This circuit combines the functions of the rectifier and DC to DC converter, rather than using the rectifier to convert AC to DC and then supplying the required voltage with regulator as in the transitional method. This modification can reduce the power consumption and the area of the circuit. This circuit also transfers the loading condition back to the external circuit by the load shift keying(LSK), determining if the input power is not enough or excessive, which increases the efficiency of the total system. The AC to DC converter is fabricated with the TSMC 90nm CMOS process. The circuit area is 0.071mm(2). The circuit can produce a 1V DC voltage with maximum output current of 10mA from an AC input ranging from 1.5V to 2V, at 1MHz to 10MHz.

Study of the choice of the decoupling layout for the ITER ICRH system

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

Vervier, M., E-mail: michel.vervier@rma.ac.be; Messiaen, A.; Ongena, J.

10 decouplers are used to neutralize the mutual coupling effects and to control the current amplitude of the 24 straps array of the ITER ICRH antenna in the case of current drive phasing. In the case of heating phasing only 4 decouplers are active and the array current control needs to act on the ratio between the power delivered by the 4 generators. This ratio is very sensitive to the precise adjustment of the antenna array phasing. The maximum total radiated power capability is then limited when the power of one generator reaches its maximum value. With the addition ofmore » four switches all 10 installed decouplers are made active and can act on all mutual coupling effects with equal source power from the 4 generators. With four more switches the current drive phasing could work with a reduced poloidal phasing resulting in a 35% increase of its coupling to the plasma.« less

Single-stage three-phase boost power factor correction circuit for AC-DC converter

NASA Astrophysics Data System (ADS)

Azazi, Haitham Z.; Ahmed, Sayed M.; Lashine, Azza E.

2018-01-01

This article presents a single-stage three-phase power factor correction (PFC) circuit for AC-to-DC converter using a single-switch boost regulator, leading to improve the input power factor (PF), reducing the input current harmonics and decreasing the number of required active switches. A novel PFC control strategy which is characterised as a simple and low-cost control circuit was adopted, for achieving a good dynamic performance, unity input PF, and minimising the harmonic contents of the input current, at which it can be applied to low/medium power converters. A detailed analytical, simulation and experimental studies were therefore conducted. The effectiveness of the proposed controller algorithm is validated by the simulation results, which were carried out using MATLAB/SIMULINK environment. The proposed system is built and tested in the laboratory using DSP-DS1104 digital control board for an inductive load. The results revealed that the total harmonic distortion in the supply current was very low. Finally, a good agreement between simulation and experimental results was achieved.

Evaluation of the antioxidant power of honey, propolis and royal jelly by amperometric flow injection analysis.

PubMed

Buratti, S; Benedetti, S; Cosio, M S

2007-02-28

In this paper is described the applicability of a flow injection system, operating with an amperometric detector, for measurement in rapid and simple way the antioxidant power of honey, propolis and royal jelly. The proposed method evaluates the reducing power of selected antioxidant compounds and does not require the use of free radicals or oxidants. Twelve honey, 12 propolis and 4 royal jelly samples of different botanical and geographical origin were evaluated by the electrochemical method and the data were compared with those obtained by the DPPH assay. Since a good correlation was found (R(2)=0.92) the proposed electrochemical method can be successfully employed for the direct, rapid and simple monitoring of the antioxidant power of honeybee products. Furthermore, the total phenolic content of samples was determined by the Folin-Ciocalteau procedure and the characteristic antioxidant activities showed a good correlation with phenolics (R(2)=0.96 for propolis and 0.90 for honey).

An Improved Harmonic Current Detection Method Based on Parallel Active Power Filter

NASA Astrophysics Data System (ADS)

Zeng, Zhiwu; Xie, Yunxiang; Wang, Yingpin; Guan, Yuanpeng; Li, Lanfang; Zhang, Xiaoyu

2017-05-01

Harmonic detection technology plays an important role in the applications of active power filter. The accuracy and real-time performance of harmonic detection are the precondition to ensure the compensation performance of Active Power Filter (APF). This paper proposed an improved instantaneous reactive power harmonic current detection algorithm. The algorithm uses an improved ip -iq algorithm which is combined with the moving average value filter. The proposed ip -iq algorithm can remove the αβ and dq coordinate transformation, decreasing the cost of calculation, simplifying the extraction process of fundamental components of load currents, and improving the detection speed. The traditional low-pass filter is replaced by the moving average filter, detecting the harmonic currents more precisely and quickly. Compared with the traditional algorithm, the THD (Total Harmonic Distortion) of the grid currents is reduced from 4.41% to 3.89% for the simulations and from 8.50% to 4.37% for the experiments after the improvement. The results show the proposed algorithm is more accurate and efficient.

Power efficient, clock gated multiplexer based full adder cell using 28 nm technology

NASA Astrophysics Data System (ADS)

Gupta, Ashutosh; Murgai, Shruti; Gulati, Anmol; Kumar, Pradeep

2016-03-01

Clock gating is a leading technique used for power saving. Full adders is one of the basic circuit that can be found in maximum VLSI circuits. In this paper clock gated multiplexer based full adder cell is implemented on 28 nm technology. We have designed a full adder cell using a multiplexer with a gated clock without degrading its performance of the cell. We have negative latch circuit for generating gated clock. This gated clock is used to control the multiplexer based full adder cell. The circuit has been synthesized on kintex FPGA through Xilinx ISE Design Suite 14.7 using 28 nm technology in Verilog HDL. The circuit has been simulated on Modelsim 10.3c. The design is verified using System Verilog on QuestaSim in UVM environment. The total power of the circuit has been reduced by 7.41% without degrading the performance of original circuit. The power has been calculated using XPower Analyzer tool of XILINX ISE DESIGN SUITE 14.3.

A wind-powered BDD electrochemical oxidation process for the removal of herbicides.

PubMed

Souza, F L; Lanza, M R V; Llanos, J; Sáez, C; Rodrigo, M A; Cañizares, P

2015-08-01

In the search for greener treatment technologies, this work studies the coupling of a wind turbine energy supply with an electrolytic cell (CWTEC device) for the remediation of wastewater polluted with pesticide 2,4-dichlorophenoxyacetic acid (2,4-D). The discontinuous and unforeseeable supply of energy is the main challenge inspiring this new proposal, which aims at reducing the environmental impact of electrolytic treatment by using a green energy supply. The results obtained using the coupled technologies are compared with those obtained by powering the electrolyser with a traditional power supply with a similar current intensity. The mineralisation of wastewater can be accomplished independently of how the electrolytic cell is powered, although differences in performance are clearly observed in the total organic carbon (TOC) and 2,4-D decays. These changes can be explained in terms of the changing profile of the current intensity, which influences the concentrations of the oxidants produced and thereby the mediated electrolytic process. Copyright © 2015 Elsevier Ltd. All rights reserved.

Antidiarrheal, Antioxidant and Antimicrobial Activities of the Musa sapientum Seed.

PubMed

Hossain, M Sarowar; Alam, M Badrul; Asadujjaman, M; Zahan, Ronok; Islam, M Monirul; Mazumder, M Ehsanul H; Haque, Md Ekramul

2011-04-01

Musa sapientum (M.sapientum) commonly known as 'banana' is widely used in Bangladeshi folk medicine for the treatment of various ailments including diarrhea. Hence, the present study was designed to investigate antidiarrheal, antioxidant and antibacterial potential of the methanolic extract of M.sapientum seed (MMSS). The extract was studied for antidiarrheal property using castor oil and magnesium sulfate induced diarrheal model and charcoal induced gastrointestinal motility test in mice. Total phenolic and flavonoids content, total antioxidant activity, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, as well as nitric oxide (NO) and assessment of reducing power were used to evaluate antioxidant potential of MMSS. In addition, disc diffusion methods were used for antibacterial assay using various diarrheal induced bacterial strains. At the doses of 100 and 200 mg/kg body weight, the extract reduced the frequency and severity of diarrhea in test animals throughout the study period. At the same doses, the extracts significantly (p<0.001) delayed the intestinal transit of charcoal meal in test animals as compared to the control. In DPPH and NO scavenging method, MMSS showed good antioxidant potentiality in a dose dependent manner with the IC(50) value of 12.32±0.33 µg/ml and 18.96±1.01 µg/ml, respectively with a significant (p<0.001) good reducing power. The extract also displayed strong anti-bacterial effect against when tested against Escherichia coli, Shigella dysenteriae, and Pseudomonas aeruginosa. Altogether, these results suggest that the MMSS could be used as a potential antidiarrheal agent along with its antioxidant and antibacterial potentiality.

Antidiarrheal, Antioxidant and Antimicrobial Activities of the Musa sapientum Seed

PubMed Central

Hossain, M. Sarowar; Alam, M. Badrul; Asadujjaman, M.; Zahan, Ronok; Islam, M. Monirul; Mazumder, M. Ehsanul H.; Haque, Md. Ekramul

2011-01-01

Musa sapientum (M.sapientum) commonly known as ‘banana’ is widely used in Bangladeshi folk medicine for the treatment of various ailments including diarrhea. Hence, the present study was designed to investigate antidiarrheal, antioxidant and antibacterial potential of the methanolic extract of M.sapientum seed (MMSS). The extract was studied for antidiarrheal property using castor oil and magnesium sulfate induced diarrheal model and charcoal induced gastrointestinal motility test in mice. Total phenolic and flavonoids content, total antioxidant activity, scavenging of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, as well as nitric oxide (NO) and assessment of reducing power were used to evaluate antioxidant potential of MMSS. In addition, disc diffusion methods were used for antibacterial assay using various diarrheal induced bacterial strains. At the doses of 100 and 200 mg/kg body weight, the extract reduced the frequency and severity of diarrhea in test animals throughout the study period. At the same doses, the extracts significantly (p<0.001) delayed the intestinal transit of charcoal meal in test animals as compared to the control. In DPPH and NO scavenging method, MMSS showed good antioxidant potentiality in a dose dependent manner with the IC50 value of 12.32±0.33 µg/ml and 18.96±1.01 µg/ml, respectively with a significant (p<0.001) good reducing power. The extract also displayed strong anti-bacterial effect against when tested against Escherichia coli, Shigella dysenteriae, and Pseudomonas aeruginosa. Altogether, these results suggest that the MMSS could be used as a potential antidiarrheal agent along with its antioxidant and antibacterial potentiality. PMID:23407989

Boosting Power Density of Microbial Fuel Cells with 3D Nitrogen‐Doped Graphene Aerogel Electrode

PubMed Central

Yang, Yang; Liu, Tianyu; Zhang, Feng; Ye, Dingding; Liao, Qiang

2016-01-01

A 3D nitrogen‐doped graphene aerogel (N‐GA) as an anode material for microbial fuel cells (MFCs) is reported. Electron microscopy images reveal that the N‐GA possesses hierarchical porous structure that allows efficient diffusion of both bacterial cells and electron mediators in the interior space of 3D electrode, and thus, the colonization of bacterial communities. Electrochemical impedance spectroscopic measurements further show that nitrogen doping considerably reduces the charge transfer resistance and internal resistance of GA, which helps to enhance the MFC power density. Importantly, the dual‐chamber milliliter‐scale MFC with N‐GA anode yields an outstanding volumetric power density of 225 ± 12 W m−3 normalized to the total volume of the anodic chamber (750 ± 40 W m−3 normalized to the volume of the anode). These power densities are the highest values report for milliliter‐scale MFCs with similar chamber size (25 mL) under the similar measurement conditions. The 3D N‐GA electrode shows great promise for improving the power generation of MFC devices. PMID:27818911

A Techno-Economic Assessment of Hybrid Cooling Systems for Coal- and Natural-Gas-Fired Power Plants with and without Carbon Capture and Storage.

PubMed

Zhai, Haibo; Rubin, Edward S

2016-04-05

Advanced cooling systems can be deployed to enhance the resilience of thermoelectric power generation systems. This study developed and applied a new power plant modeling option for a hybrid cooling system at coal- or natural-gas-fired power plants with and without amine-based carbon capture and storage (CCS) systems. The results of the plant-level analyses show that the performance and cost of hybrid cooling systems are affected by a range of environmental, technical, and economic parameters. In general, when hot periods last the entire summer, the wet unit of a hybrid cooling system needs to share about 30% of the total plant cooling load in order to minimize the overall system cost. CCS deployment can lead to a significant increase in the water use of hybrid cooling systems, depending on the level of CO2 capture. Compared to wet cooling systems, widespread applications of hybrid cooling systems can substantially reduce water use in the electric power sector with only a moderate increase in the plant-level cost of electricity generation.

Joint kinetics in rearfoot versus forefoot running: implications of switching technique.

PubMed

Stearne, Sarah M; Alderson, Jacqueline A; Green, Benjamin A; Donnelly, Cyril J; Rubenson, Jonas

2014-08-01

To better understand the mechanical factors differentiating forefoot and rearfoot strike (RFS) running, as well as the mechanical consequences of switching techniques, we assessed lower limb joint kinetics in habitual and imposed techniques in both groups. All participants performed both RFS and forefoot strike (FFS) techniques on an instrumented treadmill at 4.5 m·s while force and kinematic data were collected. Total (sum of ankle, knee, and hip) lower limb work and average power did not differ between habitual RFS and FFS runners. However, moments, negative work and negative instantaneous and average power during stance were greater at the knee in RFS and at the ankle in FFS techniques. When habitual RFS runners switched to an imposed FFS, they were able to replicate the sagittal plane mechanics of a habitual FFS; however, the ankle internal rotation moment was increased by 33%, whereas the knee abduction moments were not reduced, remaining 48.5% higher than a habitual FFS. In addition, total positive and negative lower limb average power was increased by 17% and 9%, respectively. When habitual FFS runners switched to an imposed RFS, they were able to match the mechanics of habitual RFS runners with the exception of knee abduction moments, which remained 38% lower than a habitual RFS and, surprisingly, a reduction of total lower limb positive average power of 10.5%. There appears to be no clear overall mechanical advantage of a habitual FFS or RFS. Switching techniques may have different injury implications given the altered distribution in loading between joints but should be weighed against the overall effects on limb mechanics; adopting an imposed RFS may prove the most beneficial given the absence of any clear mechanical performance decrements.

Controlling total spot power from holographic laser by superimposing a binary phase grating.

PubMed

Liu, Xiang; Zhang, Jian; Gan, Yu; Wu, Liying

2011-04-25

By superimposing a tunable binary phase grating with a conventional computer-generated hologram, the total power of multiple holographic 3D spots can be easily controlled by changing the phase depth of grating with high accuracy to a random power value for real-time optical manipulation without extra power loss. Simulation and experiment results indicate that a resolution of 0.002 can be achieved at a lower time cost for normalized total spot power.

FDTD simulation of field performance in reverberation chamber excited by two excitation antennas

NASA Astrophysics Data System (ADS)

Wang, Song; Wu, Zhan-cheng; Cui, Yao-zhong

2013-03-01

The excitation source is one of the critical items that determine the electromagnetic fields in a reverberation chamber (RC). In order to optimize the electromagnetic fields performance, a new method of exciting RC with two antennas is proposed based on theoretical analysis. The full 3D simulation of RC is carried out by the finite difference time domain (FDTD) method on two excitation conditions of one antenna and two antennas. The broadband response of RC is obtained by fast Fourier transformation (FFT) after only one simulation. Numerical data show that the field uniformity in the test space is improved on the condition of two transmitting antennas while the normalized electric fields decreased slightly compared to the one antenna condition. It is straightforward to recognize that two antennas excitation can reduce the demands on power amplifier as the total input power is split among the two antennas, and consequently the cost of electromagnetic compatibility (EMC) test in large-scale RC can be reduced.

Increased heat dissipation with the X-divertor geometry facilitating detachment onset at lower density in DIII-D

DOE PAGES

Covele, Brent; Kotschenreuther, M.; Mahajan, S.; ...

2017-06-23

The X-Divertor geometry on DIII-D has demonstrated reduced particle and heat fluxes to the target, facilitating detachment onset at ~20% lower upstream density and higher H-mode pedestal pressure than a standard divertor. SOLPS modeling suggests that this effect cannot be explained by an increase in total connection length alone, but rather by the addition of connection length specifically in the power-dissipating volume near the target, via poloidal flux expansion and flaring. But, poloidal flaring must work synergistically with divertor closure to most effectively reduce the detachment density threshold. Furthermore, the model also points to carbon radiation as the primary drivermore » of power dissipation in divertors on the DIII-D floor, which is consistent with experimental observations. Sustainable divertor detachment at lower density has beneficial consequences for energy confinement and current drive efficiency in the core for advanced tokamak (AT) operation, while simultaneously satisfying the exhaust requirements of the plasma-facing components.« less

Increased heat dissipation with the X-divertor geometry facilitating detachment onset at lower density in DIII-D

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

Covele, Brent; Kotschenreuther, M.; Mahajan, S.

The X-Divertor geometry on DIII-D has demonstrated reduced particle and heat fluxes to the target, facilitating detachment onset at ~20% lower upstream density and higher H-mode pedestal pressure than a standard divertor. SOLPS modeling suggests that this effect cannot be explained by an increase in total connection length alone, but rather by the addition of connection length specifically in the power-dissipating volume near the target, via poloidal flux expansion and flaring. But, poloidal flaring must work synergistically with divertor closure to most effectively reduce the detachment density threshold. Furthermore, the model also points to carbon radiation as the primary drivermore » of power dissipation in divertors on the DIII-D floor, which is consistent with experimental observations. Sustainable divertor detachment at lower density has beneficial consequences for energy confinement and current drive efficiency in the core for advanced tokamak (AT) operation, while simultaneously satisfying the exhaust requirements of the plasma-facing components.« less

One-electron reduced density matrices of strongly correlated harmonium atoms.

PubMed

Cioslowski, Jerzy

2015-03-21

Explicit asymptotic expressions are derived for the reduced one-electron density matrices (the 1-matrices) of strongly correlated two- and three-electron harmonium atoms in the ground and first excited states. These expressions, which are valid at the limit of small confinement strength ω, yield electron densities and kinetic energies in agreement with the published values. In addition, they reveal the ω(5/6) asymptotic scaling of the exchange components of the electron-electron repulsion energies that differs from the ω(2/3) scaling of their Coulomb and correlation counterparts. The natural orbitals of the totally symmetric ground state of the two-electron harmonium atom are found to possess collective occupancies that follow a mixed power/Gaussian dependence on the angular momentum in variance with the simple power-law prediction of Hill's asymptotics. Providing rigorous constraints on energies as functionals of 1-matrices, these results are expected to facilitate development of approximate implementations of the density matrix functional theory and ensure their proper description of strongly correlated systems.

Molecular Characterization and Antioxidant Potential of Three Wild Culinary-Medicinal Mushrooms from Tripura, Northeast India.

PubMed

Das, Aparajita Roy; Borthakur, Madhusmita; Saha, Ajay Krishna; Joshi, Santa Ram; Das, Panna

2017-01-01

The aim of this study was to characterize 3 wild culinary-medicinal mushrooms using molecular tools and to analyze their antioxidant activity. Antioxidant properties were studied by evaluating free radical scavenging, reducing power, and chelating effect. The mushrooms were identified as Lentinus squarrosulus, L. tuber-regium, and Macrocybe gigantean by amplifying internal transcribed spacer regions of ribosomal DNA. The results demonstrated that the methanolic extract of M. gigantean has the highest free radical scavenging effect and chelating effect, whereas the methanolic extract of L. squarrosulus has the highest reducing power. The highest total phenol content and the most ascorbic acid were found in the M. gigantean extracts. Among the 3 mushroom extracts, M. gigantean displayed the most potent antioxidant activity. Molecular characterization using the nuclear ribosomal internal transcribed spacer region as a universal DNA marker was an effective tool in the identification and phylogenetic analysis of the studied mushrooms. The study also indicated that these wild macrofungi are rich sources of natural antioxidants.

Total polyphenolic contents and in vitro antioxidant properties of eight Sida species from Western Ghats, India

PubMed Central

Subramanya, M. D.; Pai, Sandeep R.; Upadhya, Vinayak; Ankad, Gireesh M.; Bhagwat, Shalini S.; Hegde, Harsha V.

2015-01-01

Background: Sida L., is a medicinally important genus, the species of which are widely used in traditional systems of medicine in India. Pharmacologically, roots are known for anti-tumor, anti-HIV, hepatoprotective, and many other properties. Phenolic antioxidants help in reducing oxidative stress occurring during treatment of such diseases. Objective: The study aimed to evaluate and compare polyphenol contents and antioxidant properties of eight selected species of Sida from Western Ghats, India. Materials and Methods: Methanolic root extracts (10% w/v) of Sida species, viz., S. acuta, S. cordata, S. cordifolia, S. indica, S. mysorensis, S. retusa, S. rhombifolia, and S. spinosa were analyzed. Results: Sida cordifolia possessed highest total phenolic content (TPC: 1.92 ± 0.10 mg Caffeic Acid Equivalent/g and 2.13 ± 0.11 mg Tannic Acid Equivalant/g), total flavonoid content (TF: 2.60 ± 0.13 mg Quercetin Equivalent/g) and also possessed highest antioxidant activities in 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging (51.31 ± 2.57% Radical Scavenging Activity, (RSA); Trolox Equivalent Antioxidant Capacity: 566.25 ± 28.31μM; Ascorbic acid Equivalent Antioxidant Capacity: 477.80 ± 23.89 μM) and Ferric Reducing Antioxidant Power assays (TEAC: 590.67 ± 29.53 μM; AEAC: 600.67 ± 30.03 μM). Unlike DPPH and Ferric Reducing Antioxidant Power (FRAP) activity, 2, 2′-Azinobis (3-ethyl Benzo Thiazoline-6-Sulfonic acid) ABTS+ antioxidant activity was highest in S. indica (TEAC: 878.44 ± 43.92 μM; AEAC 968.44 ± 48.42 μM). It was significant to note that values of AEAC (μM) for all the antioxidant activities analyzed were higher than that of TEAC. Conclusion: The high contents of phenolic compounds in the root extracts of selected Sida species have direct correlation with their antioxidant properties. Conclusively, roots of S. cordifolia can be considered as the potential source of polyphenols and antioxidants. PMID:25878460

Total polyphenolic contents and in vitro antioxidant properties of eight Sida species from Western Ghats, India.

PubMed

Subramanya, M D; Pai, Sandeep R; Upadhya, Vinayak; Ankad, Gireesh M; Bhagwat, Shalini S; Hegde, Harsha V

2015-01-01

Sida L., is a medicinally important genus, the species of which are widely used in traditional systems of medicine in India. Pharmacologically, roots are known for anti-tumor, anti-HIV, hepatoprotective, and many other properties. Phenolic antioxidants help in reducing oxidative stress occurring during treatment of such diseases. The study aimed to evaluate and compare polyphenol contents and antioxidant properties of eight selected species of Sida from Western Ghats, India. Methanolic root extracts (10% w/v) of Sida species, viz., S. acuta, S. cordata, S. cordifolia, S. indica, S. mysorensis, S. retusa, S. rhombifolia, and S. spinosa were analyzed. Sida cordifolia possessed highest total phenolic content (TPC: 1.92 ± 0.10 mg Caffeic Acid Equivalent/g and 2.13 ± 0.11 mg Tannic Acid Equivalant/g), total flavonoid content (TF: 2.60 ± 0.13 mg Quercetin Equivalent/g) and also possessed highest antioxidant activities in 2,2-diphenylpicrylhydrazyl (DPPH) radical scavenging (51.31 ± 2.57% Radical Scavenging Activity, (RSA); Trolox Equivalent Antioxidant Capacity: 566.25 ± 28.31μM; Ascorbic acid Equivalent Antioxidant Capacity: 477.80 ± 23.89 μM) and Ferric Reducing Antioxidant Power assays (TEAC: 590.67 ± 29.53 μM; AEAC: 600.67 ± 30.03 μM). Unlike DPPH and Ferric Reducing Antioxidant Power (FRAP) activity, 2, 2'-Azinobis (3-ethyl Benzo Thiazoline-6-Sulfonic acid) ABTS(+) antioxidant activity was highest in S. indica (TEAC: 878.44 ± 43.92 μM; AEAC 968.44 ± 48.42 μM). It was significant to note that values of AEAC (μM) for all the antioxidant activities analyzed were higher than that of TEAC. The high contents of phenolic compounds in the root extracts of selected Sida species have direct correlation with their antioxidant properties. Conclusively, roots of S. cordifolia can be considered as the potential source of polyphenols and antioxidants.

Performance estimation of an oil-free linear compressor unit for a new compact 2K Gifford-McMahon cryocooler

NASA Astrophysics Data System (ADS)

Hiratsuka, Y.; Bao, Q.; Y Xu, M.

2017-12-01

Since 2012, a new, compact Gifford-McMahon (GM) cryocooler for cooling superconducting single photon detectors (SSPD) has been developed and reported by Sumitomo Heavy Industries, Ltd. (SHI). Also, it was reported that National Institute of Information and Communications Technology (NICT) developed a multi-channel, conduction-cooled SSPD system. However, the size and power consumption reduction becomes indispensable to apply such a system to the optical communication of AdHoc for a mobile system installed in a vehicle. The objective is to reduce the total height of the expander by 33% relative to the existing RDK-101 GM expander and to reduce the total volume of the compressor unit by 50% relative to the existing CNA-11 compressor. In addition, considering the targeted cooling application, we set the design cooling capacity targets of the first and the second stages 1 W at 60 K and 20 mW at 2.3 K respectively. In 2016, Hiratsuka et al. reported that an oil-free compressor was developed for a 2K GM cryocooler. The cooling performance of a 2K GM expander driven by an experimental unit of the linear compressor was measured. No-load temperature less than 2.1 K and the cooling capacity of 20 mW at 2.3 K were successfully achieved with an electric input power of only 1.1 kW. After that, the compressor capsule and the heat exchanger, etc. were assembled into one enclosure as a compressor unit. The total volume of the compressor unit and electrical box was significantly reduced to about 38 L, which was close to the target of 35 L. Also, the sound noise, vibration characteristics, the effect of the compressor unit inclination and the ambient temperature on the cooling performance, were evaluated. The detailed experimental results are discussed in this paper.

The role of series ankle elasticity in bipedal walking

PubMed Central

Zelik, Karl E.; Huang, Tzu-Wei P.; Adamczyk, Peter G.; Kuo, Arthur D.

2014-01-01

The elastic stretch-shortening cycle of the Achilles tendon during walking can reduce the active work demands on the plantarflexor muscles in series. However, this does not explain why or when this ankle work, whether by muscle or tendon, needs to be performed during gait. We therefore employ a simple bipedal walking model to investigate how ankle work and series elasticity impact economical locomotion. Our model shows that ankle elasticity can use passive dynamics to aid push-off late in single support, redirecting the body's center-of-mass (COM) motion upward. An appropriately timed, elastic push-off helps to reduce dissipative collision losses at contralateral heelstrike, and therefore the positive work needed to offset those losses and power steady walking. Thus, the model demonstrates how elastic ankle work can reduce the total energetic demands of walking, including work required from more proximal knee and hip muscles. We found that the key requirement for using ankle elasticity to achieve economical gait is the proper ratio of ankle stiffness to foot length. Optimal combination of these parameters ensures proper timing of elastic energy release prior to contralateral heelstrike, and sufficient energy storage to redirect the COM velocity. In fact, there exist parameter combinations that theoretically yield collision-free walking, thus requiring zero active work, albeit with relatively high ankle torques. Ankle elasticity also allows the hip to power economical walking by contributing indirectly to push-off. Whether walking is powered by the ankle or hip, ankle elasticity may aid walking economy by reducing collision losses. PMID:24365635

The role of series ankle elasticity in bipedal walking.

PubMed

Zelik, Karl E; Huang, Tzu-Wei P; Adamczyk, Peter G; Kuo, Arthur D

2014-04-07

The elastic stretch-shortening cycle of the Achilles tendon during walking can reduce the active work demands on the plantarflexor muscles in series. However, this does not explain why or when this ankle work, whether by muscle or tendon, needs to be performed during gait. We therefore employ a simple bipedal walking model to investigate how ankle work and series elasticity impact economical locomotion. Our model shows that ankle elasticity can use passive dynamics to aid push-off late in single support, redirecting the body's center-of-mass (COM) motion upward. An appropriately timed, elastic push-off helps to reduce dissipative collision losses at contralateral heelstrike, and therefore the positive work needed to offset those losses and power steady walking. Thus, the model demonstrates how elastic ankle work can reduce the total energetic demands of walking, including work required from more proximal knee and hip muscles. We found that the key requirement for using ankle elasticity to achieve economical gait is the proper ratio of ankle stiffness to foot length. Optimal combination of these parameters ensures proper timing of elastic energy release prior to contralateral heelstrike, and sufficient energy storage to redirect the COM velocity. In fact, there exist parameter combinations that theoretically yield collision-free walking, thus requiring zero active work, albeit with relatively high ankle torques. Ankle elasticity also allows the hip to power economical walking by contributing indirectly to push-off. Whether walking is powered by the ankle or hip, ankle elasticity may aid walking economy by reducing collision losses. Copyright © 2013 Elsevier Ltd. All rights reserved.

Ankle and Midfoot Power During Walking and Stair Ascent in Healthy Adults.

PubMed

DiLiberto, Frank E; Nawoczenski, Deborah A; Houck, Jeff

2018-02-27

Ankle power dominates forward propulsion of gait, but midfoot power generation is also important for successful push off. However, it is unclear if midfoot power generation increases or stays the same in response to propulsive activities that induce larger external loads and require greater ankle power. The purpose of this study was to examine ankle and midfoot power in healthy adults during progressively more demanding functional tasks. Multi-segment foot motion (tibia, calcaneus, forefoot) and ground reaction forces were recorded as participants (N=12) walked, ascended a standard step, and ascended a high step. Ankle and midfoot positive peak power and total power, and the proportion of midfoot to ankle total power were calculated. One-way repeated measures ANOVAs were conducted to evaluate differences across tasks. Main effects were found for ankle and midfoot peak and total powers (all p < .001), but not for the proportion of midfoot to ankle total power (p = .331). Ankle and midfoot power significantly increased across each task. Midfoot power increased in proportion to ankle power and in congruence to the external load of a task. Study findings may serve to inform multi-segment foot modeling applications and internal mechanistic theories of normal and pathological foot function.

Validation of a high-power, time-resolved, near-infrared spectroscopy system for measurement of superficial and deep muscle deoxygenation during exercise.

PubMed

Koga, Shunsaku; Barstow, Thomas J; Okushima, Dai; Rossiter, Harry B; Kondo, Narihiko; Ohmae, Etsuko; Poole, David C

2015-06-01

Near-infrared assessment of skeletal muscle is restricted to superficial tissues due to power limitations of spectroscopic systems. We reasoned that understanding of muscle deoxygenation may be improved by simultaneously interrogating deeper tissues. To achieve this, we modified a high-power (∼8 mW), time-resolved, near-infrared spectroscopy system to increase depth penetration. Precision was first validated using a homogenous optical phantom over a range of inter-optode spacings (OS). Coefficients of variation from 10 measurements were minimal (0.5-1.9%) for absorption (μa), reduced scattering, simulated total hemoglobin, and simulated O2 saturation. Second, a dual-layer phantom was constructed to assess depth sensitivity, and the thickness of the superficial layer was varied. With a superficial layer thickness of 1, 2, 3, and 4 cm (μa = 0.149 cm(-1)), the proportional contribution of the deep layer (μa = 0.250 cm(-1)) to total μa was 80.1, 26.9, 3.7, and 0.0%, respectively (at 6-cm OS), validating penetration to ∼3 cm. Implementation of an additional superficial phantom to simulate adipose tissue further reduced depth sensitivity. Finally, superficial and deep muscle spectroscopy was performed in six participants during heavy-intensity cycle exercise. Compared with the superficial rectus femoris, peak deoxygenation of the deep rectus femoris (including the superficial intermedius in some) was not significantly different (deoxyhemoglobin and deoxymyoglobin concentration: 81.3 ± 20.8 vs. 78.3 ± 13.6 μM, P > 0.05), but deoxygenation kinetics were significantly slower (mean response time: 37 ± 10 vs. 65 ± 9 s, P ≤ 0.05). These data validate a high-power, time-resolved, near-infrared spectroscopy system with large OS for measuring the deoxygenation of deep tissues and reveal temporal and spatial disparities in muscle deoxygenation responses to exercise. Copyright © 2015 the American Physiological Society.

Maturation of heart rate and blood pressure variability during sleep in term-born infants.

PubMed

Yiallourou, Stephanie R; Sands, Scott A; Walker, Adrian M; Horne, Rosemary S C

2012-02-01

Abnormal blood pressure control is implicated in the sudden infant death syndrome (SIDS). However, no data exist on normal development of blood pressure control during infancy. This study assessed maturation of autonomic control of blood pressure and heart rate during sleep within the first 6 months of life. Term infants (n = 31) were studied longitudinally at 2-4 weeks, 2-3 months, and 5-6 months postnatal age. Infants underwent daytime polysomnography at each age studied. Blood pressure and heart rate were recorded during quiet (QS) and active (AS) sleep in undisturbed baseline and head-up tilt conditions. Autonomic control was assessed using spectral indices of blood pressure and heart rate variability (BPV and HRV) in ranges of low frequency (LF, reflecting sympathetic + parasympathetic activity) and high frequency (HF, parasympathetic activity), total power (LF+HF), and LF/HF ratio (sympathovagal balance). With increasing postnatal age and predominantly during QS, HRV-LF, HRV-HF, and HRV total power increased, while HRV-LF/HF decreased. BPV-LF/HF also decreased with postnatal age. All changes were evident in both baseline and head-up tilt conditions. BPV-LF and BPV total power during tilts were markedly reduced in QS versus AS at each age. In sleeping infants, sympathetic vascular modulation of the circulation decreases with age, while parasympathetic control of heart rate is strengthened. These normative data will aid in the early identification of conditions where autonomic function is impaired, such as in SIDS.

Exploring the meteorological potential for planning a high performance European electricity super-grid: optimal power capacity distribution among countries

NASA Astrophysics Data System (ADS)

Santos-Alamillos, Francisco J.; Brayshaw, David J.; Methven, John; Thomaidis, Nikolaos S.; Ruiz-Arias, José A.; Pozo-Vázquez, David

2017-11-01

The concept of a European super-grid for electricity presents clear advantages for a reliable and affordable renewable power production (photovoltaics and wind). Based on the mean-variance portfolio optimization analysis, we explore optimal scenarios for the allocation of new renewable capacity at national level in order to provide to energy decision-makers guidance about which regions should be mostly targeted to either maximize total production or reduce its day-to-day variability. The results show that the existing distribution of renewable generation capacity across Europe is far from optimal: i.e. a ‘better’ spatial distribution of resources could have been achieved with either a ~31% increase in mean power supply (for the same level of day-to-day variability) or a ~37.5% reduction in day-to-day variability (for the same level of mean productivity). Careful planning of additional increments in renewable capacity at the European level could, however, act to significantly ameliorate this deficiency. The choice of where to deploy resources depends, however, on the objective being pursued—if the goal is to maximize average output, then new capacity is best allocated in the countries with highest resources, whereas investment in additional capacity in a north/south dipole pattern across Europe would act to most reduce daily variations and thus decrease the day-to-day volatility of renewable power supply.

In vitro antioxidant and, α-glucosidase inhibitory activities and comprehensive metabolite profiling of methanol extract and its fractions from Clinacanthus nutans.

PubMed

Alam, Md Ariful; Zaidul, I S M; Ghafoor, Kashif; Sahena, F; Hakim, M A; Rafii, M Y; Abir, H M; Bostanudin, M F; Perumal, V; Khatib, A

2017-03-31

This study was aimed to evaluate antioxidant and α-glucosidase inhibitory activity, with a subsequent analysis of total phenolic and total flavonoid content of methanol extract and its derived fractions from Clinacanthus nutans accompanied by comprehensive phytochemical profiling. Liquid-liquid partition chromatography was used to separate methanolic extract to get hexane, ethyl acetate, butanol and residual aqueous fractions. The total antioxidant activity was determined by 2,2-diphenyl-1-picrylhydrazy (DPPH) radical scavenging and ferric reducing antioxidant power assay (FRAP). The antidiabetic activity of methanol extract and its consequent fractions were examined by α-glucosidase inhibitory bioassay. The chemical profiling was carried out by gas chromatography coupled with quadrupole time-of-flight mass spectrometry (GC Q-TOF MS). The total yield for methanol extraction was (12.63 ± 0.98) % (w/w) and highest fractionated value found for residual aqueous (52.25 ± 1.01) % (w/w) as compared to the other fractions. Significant DPPH free radical scavenging activity was found for methanolic extract (63.07 ± 0.11) % and (79.98 ± 0.31) % for ethyl acetate fraction among all the fractions evaluated. Methanol extract was the most prominent in case of FRAP (141.89 ± 0.87 μg AAE/g) whereas most effective reducing power observed in ethyl acetate fraction (133.6 ± 0.2987 μg AAE/g). The results also indicated a substantial α-glucosidase inhibitory activity for butanol fraction (72.16 ± 1.0) % and ethyl acetate fraction (70.76 ± 0.49) %. The statistical analysis revealed that total phenolic and total flavonoid content of the samples had the significant (p < 0.05) impact on DPPH free radical scavenging and α-glucosidase inhibitory activity. Current results proposed the therapeutic potential of Clinacanthus nutans, especially ethyl acetate and butanol fraction as chemotherapeutic agent against oxidative related cellular damages and control the postprandial hyperglycemia. The phytochemical investigation showed the existence of active constituents in Clinacanthus nutans extract and fractions.

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

Huskey, A.; Bowen, A.; Jager, D.

This test was conducted as part of the U.S. Department of Energy's (DOE) Independent Testing project. This project was established to help reduce the barriers to wind energy expansion by providing independent testing results for small wind turbines (SWT). In total, five turbines were tested at the National Wind Technology Center (NWTC) as a part of this project. Safety and function testing is one of up to five tests performed on the turbines, including power performance, duration, noise, and power-quality tests. NWTC testing results provide manufacturers with reports that may be used to meet part of small wind turbine certificationmore » requirements. The test equipment includes a Mariah Windspire wind turbine mounted on a monopole tower. L&E Machine manufactured the turbine in the United States. The inverter was manufactured separately by Technology Driven Products in the United States. The system was installed by the NWTC site operations group with guidance and assistance from Mariah Power.« less

Honey as an apitherapic product: its inhibitory effect on urease and xanthine oxidase.

PubMed

Sahin, Huseyin

2016-01-01

The aim of this study was to evaluate new natural inhibitor sources for the enzymes urease and xanthine oxidase (XO). Chestnut, oak and polyfloral honey extracts were used to determine inhibition effects of both enzymes. In addition to investigate inhibition, the antioxidant capacities of these honeys were determined using total phenolic content (TPC), ferric reducing antioxidant power (FRAP), and DPPH radical scavenging activity assays. Due to their high phenolic content, chestnut and oak honeys are found to be a powerful source for inhibition of both enzymes. Especially, oak honeys were efficient for urease inhibition with 0.012-0.021 g/mL IC50 values, and also chestnut honeys were powerful for XO inhibition with 0.028-0.039 g/mL IC50 values. Regular daily consumption of these honeys can prevent gastric ulcers deriving from Helicobacter pylori and pathological disorders mediated by reactive oxygen species.

A smart, intermittent driven particle sensor with an airflow change trigger using a lead zirconate titanate (PZT) cantilever

NASA Astrophysics Data System (ADS)

Takahashi, Hidetoshi; Tomimatsu, Yutaka; Kobayashi, Takeshi; Isozaki, Akihiro; Itoh, Toshihiro; Maeda, Ryutaro; Matsumoto, Kiyoshi; Shimoyama, Isao

2014-02-01

This paper reports on a smart, intermittent driven particle sensor with an airflow trigger. A lead zirconate titanate cantilever functions as the trigger, which detects an airflow change without requiring a power supply to drive the sensing element. Because an airflow change indicates that the particle concentration has changed, the trigger switches the optical particle counter from sleep mode to active mode only when the particle concentration surrounding the sensor changes. The sensor power consumption in sleep mode is 100 times less than that in the active mode. Thus, this intermittent driven method significantly reduces the total power consumption of the particle sensor. In this paper, we fabricate a prototype of the particle sensor and demonstrate that the optical particle counter can be switched on by the fabricated trigger and thus that the particle concentration can be measured.

Recent Large Reduction in Sulfur Dioxide Emissions from Chinese Power Plants Observed by the Ozone Monitoring Instrument

NASA Technical Reports Server (NTRS)

Li, Can; Zhang, Qiang; Krotkov, Nickolay A.; Streets, David G.; He, Kebin; Tsay, Si-Chee; Gleason, James F.

2010-01-01

The Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite observed substantial increases in total column SO2 and tropospheric column NO2 from 2005 to 2007, over several areas in northern China where large coal-fired power plants were built during this period. The OMI-observed SO2/NO2 ratio is consistent with the SO2/ NO2, emissions estimated from a bottom-up approach. In 2008 over the same areas, OMI detected little change in NO2, suggesting steady electricity output from the power plants. However, dramatic reductions of S0 2 emissions were observed by OMI at the same time. These reductions confirm the effectiveness of the flue-gas desulfurization (FGD) devices in reducing S02 emissions, which likely became operational between 2007 and 2008. This study further demonstrates that the satellite sensors can monitor and characterize anthropogenic emissions from large point sources.

When the test of mediation is more powerful than the test of the total effect.

PubMed

O'Rourke, Holly P; MacKinnon, David P

2015-06-01

Although previous research has studied power in mediation models, the extent to which the inclusion of a mediator will increase power has not been investigated. To address this deficit, in a first study we compared the analytical power values of the mediated effect and the total effect in a single-mediator model, to identify the situations in which the inclusion of one mediator increased statistical power. The results from this first study indicated that including a mediator increased statistical power in small samples with large coefficients and in large samples with small coefficients, and when coefficients were nonzero and equal across models. Next, we identified conditions under which power was greater for the test of the total mediated effect than for the test of the total effect in the parallel two-mediator model. These results indicated that including two mediators increased power in small samples with large coefficients and in large samples with small coefficients, the same pattern of results that had been found in the first study. Finally, we assessed the analytical power for a sequential (three-path) two-mediator model and compared the power to detect the three-path mediated effect to the power to detect both the test of the total effect and the test of the mediated effect for the single-mediator model. The results indicated that the three-path mediated effect had more power than the mediated effect from the single-mediator model and the test of the total effect. Practical implications of these results for researchers are then discussed.

Enhanced magnetic domain relaxation frequency and low power losses in Zn2+ substituted manganese ferrites potential for high frequency applications

NASA Astrophysics Data System (ADS)

Praveena, K.; Chen, Hsiao-Wen; Liu, Hsiang-Lin; Sadhana, K.; Murthy, S. R.

2016-12-01

Nowadays electronic industries prerequisites magnetic materials, i.e., iron rich materials and their magnetic alloys. However, with the advent of high frequency applications, the standard techniques of reducing eddy current losses, using iron cores, were no longer efficient or cost effective. Current market trends of the switched mode power supplies industries required even low energy losses in power conversion with maintenance of adequate initial permeability. From the above point of view, in the present study we aimed at the production of Manganese-Zinc ferrites prepared via solution combustion method using mixture of fuels and achieved low loss, high saturation magnetization, high permeability, and high magnetic domain relaxation frequency. The as-synthesized Zn2+ substituted MnFe2O4 were characterized by X-ray diffractometer (XRD) and transmission electron microscopy (TEM). The fractions of Mn2+, Zn2+ and Fe2+ cations occupying tetrahedral sites along with Fe occupying octahedral sites within the unit cell of all ferrite samples were estimated by Raman scattering spectroscopy. The magnetic domain relaxation was investigated by inductance spectroscopy (IS) and the observed magnetic domain relaxation frequency (fr) was increased with the increase in grain size. The real and imaginary part of permeability (μ‧ and μ″) increased with frequency and showed a maximum above 100 MHz. This can be explained on the basis of spin rotation and domain wall motion. The saturation magnetization (Ms), remnant magnetization (Mr) and magneton number (μB) decreased gradually with increasing Zn2+ concentration. The decrease in the saturation magnetization was discussed with Yafet-Kittel (Y-K) model. The Zn2+ concentration increases the relative number of ferric ions on the A sites, reduces the A-B interactions. The frequency dependent total power losses decreased as the zinc concentration increased. At 1 MHz, the total power loss (Pt) changed from 358 mW/cm3 for x=0-165 mW/cm3 for x=0.9. Pt for all the Zn doped samples exhibited the temperature stability up to 100 °C.

Alcohol Hits You When It Is Hard: Intoxication, Task Difficulty, and Theta Brain Oscillations.

PubMed

Rosen, Burke Q; Padovan, Nevena; Marinkovic, Ksenija

2016-04-01

Alcohol intoxication is known to impair decision making in a variety of situations. Previous neuroimaging evidence suggests that the neurofunctional system subserving controlled processing is especially vulnerable to alcohol in conflict-evoking tasks. The present study investigated the effects of moderate alcohol intoxication on the spatiotemporal neural dynamics of event-related total theta (4 to 7 Hz) power as a function of task difficulty. Two variants of the Simon task manipulated incongruity via simple spatial stimulus-response mismatch and, in a more difficult version, by combining spatial and semantic interference. Healthy social drinkers participated in both alcohol (0.6 g/kg ethanol for men, 0.55 g/kg for women) and placebo conditions in a counterbalanced design. Whole-head magnetoencephalography (MEG) signals were acquired and event-related total theta power was calculated on each trial with Morlet wavelets. MEG sources were estimated using anatomically constrained, noise-normalized, spectral dynamic statistical parametric mapping. Longer reaction times and lower accuracy confirmed the difficulty manipulation. Response conflict (incongruity) increased and alcohol intoxication decreased event-related theta power overall during both tasks bilaterally in the medial and ventrolateral prefrontal cortices. However, alcohol-induced theta suppression was selective for conflict only in the more difficult task which engaged the dorsal anterior cingulate (dAC) and anterior inferolateral prefrontal cortices. Theta power correlated negatively with drinking levels and disinhibition, suggesting that cognitive control is susceptible in more impulsive individuals with higher alcohol intake. The spatiotemporal theta profile across the 2 tasks supports the concept of a rostrocaudal activity gradient in the medial prefrontal cortex that is modulated by task difficulty, with the dAC as the key node in the network subserving cognitive control. Conflict-related theta power was selectively reduced by alcohol only under the more difficult task which is indicative of the alcohol-induced impairment of conflict monitoring and top-down regulation. Compromised executive control under alcohol may underlie a range of adverse effects including reduced competency in conflict-inducing or complex situations. © 2016 The Authors. Alcoholism: Clinical and Experimental Research published by Wiley Periodicals, Inc. on behalf of Research Society on Alcoholism.

Efficiency enhancement for natural gas liquefaction with CO2 capture and sequestration through cycles innovation and process optimization

NASA Astrophysics Data System (ADS)

Alabdulkarem, Abdullah

Liquefied natural gas (LNG) plants are energy intensive. As a result, the power plants operating these LNG plants emit high amounts of CO2 . To mitigate global warming that is caused by the increase in atmospheric CO2, CO2 capture and sequestration (CCS) using amine absorption is proposed. However, the major challenge of implementing this CCS system is the associated power requirement, increasing power consumption by about 15--25%. Therefore, the main scope of this work is to tackle this challenge by minimizing CCS power consumption as well as that of the entire LNG plant though system integration and rigorous optimization. The power consumption of the LNG plant was reduced through improving the process of liquefaction itself. In this work, a genetic algorithm (GA) was used to optimize a propane pre-cooled mixed-refrigerant (C3-MR) LNG plant modeled using HYSYS software. An optimization platform coupling Matlab with HYSYS was developed. New refrigerant mixtures were found, with savings in power consumption as high as 13%. LNG plants optimization with variable natural gas feed compositions was addressed and the solution was proposed through applying robust optimization techniques, resulting in a robust refrigerant which can liquefy a range of natural gas feeds. The second approach for reducing the power consumption is through process integration and waste heat utilization in the integrated CCS system. Four waste heat sources and six potential uses were uncovered and evaluated using HYSYS software. The developed models were verified against experimental data from the literature with good agreement. Net available power enhancement in one of the proposed CCS configuration is 16% more than the conventional CCS configuration. To reduce the CO2 pressurization power into a well for enhanced oil recovery (EOR) applications, five CO2 pressurization methods were explored. New CO2 liquefaction cycles were developed and modeled using HYSYS software. One of the developed liquefaction cycles using NH3 as a refrigerant resulted in 5% less power consumption than the conventional multi-stage compression cycle. Finally, a new concept of providing the CO2 regeneration heat is proposed. The proposed concept is using a heat pump to provide the regeneration heat as well as process heat and CO2 liquefaction heat. Seven configurations of heat pumps integrated with CCS were developed. One of the heat pumps consumes 24% less power than the conventional system or 59% less total equivalent power demand than the conventional system with steam extraction and CO2 compression.

Efficient data communication protocols for wireless networks

NASA Astrophysics Data System (ADS)

Zeydan, Engin

In this dissertation, efficient decentralized algorithms are investigated for cost minimization problems in wireless networks. For wireless sensor networks, we investigate both the reduction in the energy consumption and throughput maximization problems separately using multi-hop data aggregation for correlated data in wireless sensor networks. The proposed algorithms exploit data redundancy using a game theoretic framework. For energy minimization, routes are chosen to minimize the total energy expended by the network using best response dynamics to local data. The cost function used in routing takes into account distance, interference and in-network data aggregation. The proposed energy-efficient correlation-aware routing algorithm significantly reduces the energy consumption in the network and converges in a finite number of steps iteratively. For throughput maximization, we consider both the interference distribution across the network and correlation between forwarded data when establishing routes. Nodes along each route are chosen to minimize the interference impact in their neighborhood and to maximize the in-network data aggregation. The resulting network topology maximizes the global network throughput and the algorithm is guaranteed to converge with a finite number of steps using best response dynamics. For multiple antenna wireless ad-hoc networks, we present distributed cooperative and regret-matching based learning schemes for joint transmit beanformer and power level selection problem for nodes operating in multi-user interference environment. Total network transmit power is minimized while ensuring a constant received signal-to-interference and noise ratio at each receiver. In cooperative and regret-matching based power minimization algorithms, transmit beanformers are selected from a predefined codebook to minimize the total power. By selecting transmit beamformers judiciously and performing power adaptation, the cooperative algorithm is shown to converge to pure strategy Nash equilibrium with high probability throughout the iterations in the interference impaired network. On the other hand, the regret-matching learning algorithm is noncooperative and requires minimum amount of overhead. The proposed cooperative and regret-matching based distributed algorithms are also compared with centralized solutions through simulation results.

Vulnerability of US and European electricity supply to climate change

NASA Astrophysics Data System (ADS)

van Vliet, Michelle T. H.; Yearsley, John R.; Ludwig, Fulco; Vögele, Stefan; Lettenmaier, Dennis P.; Kabat, Pavel

2012-09-01

In the United States and Europe, at present 91% and 78% (ref. ) of the total electricity is produced by thermoelectric (nuclear and fossil-fuelled) power plants, which directly depend on the availability and temperature of water resources for cooling. During recent warm, dry summers several thermoelectric power plants in Europe and the southeastern United States were forced to reduce production owing to cooling-water scarcity. Here we show that thermoelectric power in Europe and the United States is vulnerable to climate change owing to the combined impacts of lower summer river flows and higher river water temperatures. Using a physically based hydrological and water temperature modelling framework in combination with an electricity production model, we show a summer average decrease in capacity of power plants of 6.3-19% in Europe and 4.4-16% in the United States depending on cooling system type and climate scenario for 2031-2060. In addition, probabilities of extreme (>90%) reductions in thermoelectric power production will on average increase by a factor of three. Considering the increase in future electricity demand, there is a strong need for improved climate adaptation strategies in the thermoelectric power sector to assure futureenergy security.

DOD fuel cell demonstration program

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

Holcomb, F.H.; Binder, M.J.; Taylor, W.R.

The supply of reliable, cost-effective electric power with minimal environmental impact is a constant concern of Department of Defense (DOD) installation energy personnel. Electricity purchased from the local utility is expensive and represents only about 30% of the original energy input at the generating station due to generation and distribution inefficiencies. Because of master metering and large air conditioning loads, the demand portion of the installation`s electric bill can be in excess of 50% of the total bill. While the electric utilities in the United States have a very good record of reliability, there is significant potential for improving themore » security of electrical power supplied by using on-site power generation. On-site, dispersed power generation can reduce power outages due to weather, terrorist activities, or lack of utility generating capacity. In addition, as increased emphasis is placed on global warming, acid rain, and air pollution in general, the development of clean, highly efficient power producing technologies is not only desirable, but mandatory. Since the majority of central heat plants on U.S. military installations are nearing the end of their useful life, there is an opportunity to replace outdated existing equipment with modem technologies.« less

Scavenging capacity of strawberry tree (Arbutus unedo L.) leaves on free radicals.

PubMed

Oliveira, Ivo; Coelho, Valentim; Baltasar, Raquel; Pereira, José Alberto; Baptista, Paula

2009-07-01

Despite strawberry tree (Arbutus unedo L.) leaves had a long use in traditional medicine due to its antiseptic, diuretic, astringent and depurative properties, the potential of their antioxidant activity are still lacking. Our study goals to assess the antioxidant and free radical scavenging potential of water, ethanol, methanol and diethyl ether extracts of A. unedo leaves. Total phenols content was achieved spectrophotometrically using Folin-Ciocalteau reagent with gallic acid as standard. Antioxidant activity was evaluated using three different methods: reducing power of iron (III)/ferricyanide complex assay, scavenging effect on DPPH (2,2-diphenyl-1-picrylhydrazyl) radicals and scavenging effect on superoxide radicals by using the PMS-NADH-nitroblue tetrazolium system. Ethanol extracts of A. unedo leaves were the highest in reducing power (IC(50) 232.7 microg/mL) and DPPH scavenging effect (IC(50) 63.2 microg/mL) followed by water extracts (with IC(50) of 287.7 and 73.7 microg/mL, respectively); whereas diethyl ether extracts were the lowest. In the scavenging on superoxide radical assay, methanol extracts obtained the best results (IC(50) 6.9 microg/mL). For all the methods tested the antioxidant activity was concentration dependent. In accordance with antioxidant activity, highest total phenols content were found in ethanol, followed by water, methanol and diethyl ether extract. The results indicated that A. unedo leaves are a potential source of natural antioxidants.

Content of insoluble bound phenolics in millets and their contribution to antioxidant capacity.

PubMed

Chandrasekara, Anoma; Shahidi, Fereidoon

2010-06-09

Soluble and insoluble-bound phenolic extracts of several varieties of millet (kodo, finger, foxtail, proso, pearl, and little millets) whole grains were evaluated for their phenolic contents and antioxidative efficacy using trolox equivalent antioxidant capacity (TEAC), reducing power (RP), and beta-carotene-linoleate model system as well as ferrous chelating activity. In addition, ferulic and p-coumaric acids were present in soluble and bound phenolic fractions of millets, and their contents were determined using high-performance liquid chromatography (HPLC) and HPLC-mass spectrometry (MS). Kodo millet had the highest total phenolic content, whereas proso millet possessed the least. All millet varieties showed high antioxidant activities, although the order of their efficacy was assay dependent. HPLC analysis of millet phenolic extracts demonstrated that the bound fractions contained more ferulic and p-coumaric acids compared to their soluble counterparts. The results of this study showed that soluble as well as bound fractions of millet grains are rich sources of phenolic compounds with antioxidant, metal chelating, and reducing power. The potential of whole millets as natural sources of antioxidants depends on the variety used. The importance of the insoluble bound fraction of millet as a source of ferulic acid and p-coumaric acid was established, and their contribution to the total phenolic content must be taken into account in the assessment of the antioxidant activity of millets.

Characterization and in vitro antioxidant activity of Albizia stipulata Boiv. gum exudates.

PubMed

Thanzami, K; Malsawmtluangi, C; Lalhlenmawia, H; Seelan, T Veenus; Palanisamy, Selvamani; Kandasamy, Ruckmani; Pachuau, Lalduhsanga

2015-09-01

The objective of the present study is to characterize the physicochemical properties and to determine the in vitro antioxidant activity of Albizia stipulata Boiv. gum exudates collected from Northeast India. The total carbohydrate, uronic acid and protein contents, monosaccharide composition and the molecular weight distribution of the purified gum was determined. The powder flow property and preliminary compressibility test were performed on the dried gum exudates. Fourier transform infrared spectroscopy (FTIR) study was performed to analyze the functional groups present in the structure. Differential scanning calorimetry (DSC) and thermogravimetry (TGA/DTA) analyses were performed to study the thermal stability of the gum. The antioxidant properties of the gum were evaluated by determining 2,2-diphenyl-1-picrylhydrazyl (DPPH), hydroxyl scavenging activities and reducing power. The total carbohydrate and protein contents of the gum were found to be 75.17±3.21% and 2.60±1.05% respectively. The viscosity of 2% aqueous solution of the gum exhibited non-Newtonian type of flow showing pH dependent swelling. Arabinose and galactose were found to be the main monosaccharides present in the gum exudates and the molecular weight distribution of the gum was also found to be polydispersed. Results from DPPH, hydroxyl scavenging and reducing power studies showed the gum possesses antioxidant properties. Copyright © 2015 Elsevier B.V. All rights reserved.

Revisiting galactic black hole binary GX 339-4 by using 2007 – 2014 Swift XRT observations

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

Azizi, Febrie Ahmad; Vierdayanti, Kiki; Putra, Mahasena

2015-09-30

This work aims to study the X-ray properties of the galactic black hole binary GX 339-4. Focus of the study is on exploration of data from Swift-XRT in exclusively photon-counting mode. We use data from 2007 up to August 2014, which contain about 40 pointing observations with level 1 data. The flux of GX 339-4 varies in a factor of 100 during this period of observations. For the purpose of this work, we also try to develop a system to conduct standard SWIFT XRT data reduction automatically, in order to greatly reduce time when working with data bulk, which producesmore » images, lightcurves as well as spectra. We also develop another system to conduct fitting of bulk spectral data with a two-component model, disk blackbody and power-law. The fitting results show that no data have a reduced chi-squared > 2. The fraction of the disk to total flux and the power-law to total flux range from 0.00389 – 0.994 and 0.00605 – 0.996, respectively. From the analysis of the disk component, we obtain the value of the innermost disk radius that does not show any large scale truncation which is in a good agreement with a previous study that used 2007 – 2011 Swift-XRT data, indicating that the systems we developed work properly.« less

Adults with initial metabolic syndrome have altered muscle deoxygenation during incremental exercise.

PubMed

Machado, Alessandro da Costa; Barbosa, Thales Coelho; Kluser Sales, Allan Robson; de Souza, Marcio Nogueira; da Nóbrega, Antonio Claudio Lucas; Silva, Bruno Moreira

2017-02-01

Reduced aerobic power is independently associated with metabolic syndrome (MetS) incidence and prevalence in adults. This study investigated whether muscle deoxygenation (proxy of microvascular O 2 extraction) during incremental exercise is altered in MetS and associated with reduced oxygen consumption ( V˙O 2peak ). Twelve men with initial MetS (no overt diseases and medication-naive; mean ± SD, age 38 ± 7 years) and 12 healthy controls (HCs) (34 ± 7 years) completed an incremental cycling test to exhaustion, in which pulmonary ventilation and gas exchange (metabolic analyzer), as well as vastus lateralis deoxygenation (near infrared spectroscopy), were measured. Subjects with MetS, in contrast to HCs, showed lower V˙O 2peak normalized to total lean mass, similar V˙O 2 response to exercise, and earlier break point (BP) in muscle deoxygenation. Consequently, deoxygenation slope from BP to peak exercise was greater. Furthermore, absolute V˙O 2peak was positively associated with BP in correlations adjusted for total lean mass. MetS, without overt diseases, altered kinetics of muscle deoxygenation during incremental exercise, particularly at high-intensity exercise. Therefore, the balance between utilization and delivery of O 2 within skeletal muscle is impaired early in MetS natural history, which may contribute to the reduction in aerobic power. © 2017 The Obesity Society.

Enhanced antioxidative activity of soybean koji prepared with various filamentous fungi.

PubMed

Lin, Chia-Hung; Wei, Yi-Tien; Chou, Cheng-Chun

2006-10-01

In the present study, soybean koji fermented with various GRAS filamentous fungi, including Aspergillus sojae BCRC 30103, Aspergillus oryzae BCRC 30222, Aspergillus awamori, Actinomucor taiwanensis and Rhizopus sp. These organisms are commonly used as starters in the fermentation of many traditional, oriental food products. The growth of starter organisms, total phenolic content, and antioxidative activities of the methanol extract of these kojis are compared with specific reference to alpha-diphenyl-2-picryl-hydrozyl (DPPH) radicals scavenging effects, Fe2+-chelating ability, and reducing power. Depending on starter organism, various extents of mycelia propagation (35.23-86.29 mg/g koji) were noted after 3 days of fermentation. Total phenolic content increased in soybean after fermentation. Koji also displayed enhanced antioxidative activates in comparison with the non-fermented soybean. Among the five kinds of koji tested, those fermented with Asp. awamori exhibited the highest levels of DPPH-free radicals scavenging activity, Fe2+-chelating ability and reducing power. The DPPH-free radicals scavenging activity and Fe2+-chelating ability of this soybean koji was ca. 8.9 and 6.7 fold that of the control. Analysis of the dose-response effect also revealed that before reaching a threshold point, there is a linear relationship between increases in antioxidative activity and increases in the concentration of the koji extract. These results show the potential for developing a healthy food supplement with soybean fermented by the GRAS filamentous fungi.

Ramalina capitata (Ach.) Nyl. acetone extract: HPLC analysis, genotoxicity, cholinesterase, antioxidant and antibacterial activity.

PubMed

Zrnzevic, Ivana; Stankovic, Miroslava; Stankov Jovanovic, Vesna; Mitic, Violeta; Dordevic, Aleksandra; Zlatanovic, Ivana; Stojanovic, Gordana

2017-01-01

In the present investigation, effects of Ramalina capitata acetone extract on micronucleus distribution on human lymphocytes, on cholinesterase activity and antioxidant activity (by the CUPRAC method) were examined, for the first time as well as its HPLC profile. Additionally, total phenolic compounds (TPC), antioxidant properties (estimated via DPPH, ABTS and TRP assays) and antibacterial activity were determined. The predominant phenolic compounds in this extract were evernic, everninic and obtusatic acids. Acetone extract of R. capitata at concentration of 2 μg mL -1 decreased a frequency of micronuclei (MN) for 14.8 %. The extract reduces the concentration of DPPH and ABTS radicals for 21.2 and 36.1 % (respectively). Values for total reducing power (TRP) and cupric reducing capacity (CUPRAC) were 0.4624 ± 0.1064 μg ascorbic acid equivalents (AAE) per mg of dry extract, and 6.1176 ± 0.2964 μg Trolox equivalents (TE) per mg of dry extract, respectively. The total phenol content was 670.6376 ± 66.554 μg galic acid equivalents (GAE) per mg of dry extract. Tested extract at concentration of 2 mg mL -1 exhibited inhibition effect (5.2 %) on pooled human serum cholinesterase. The antimicrobial assay showed that acetone extract had inhibition effect towards Gram-positive strains. The results of manifested antioxidant activity, reducing the number of micronuclei in human lymphocytes, and antibacterial activity recommends R. capitata extract for further in vivo studies.

Development of a precise controller for an electrohydraulic total artificial heart. Improvement of the motor's dynamic response.

PubMed

Ahn, J M; Masuzawa, T; Taenaka, Y; Tatsumi, E; Ohno, T; Choi, W W; Toda, K; Miyazaki, K; Baba, Y; Nakatani, T; Takano, H; Min, B G

1996-01-01

In an electrohydraulic total artificial heart developed at the National Cardiovascular Center (Osaka, Japan), two blood pumps are pushed alternatively by means of the bidirectional motion of a brushless DC motor for pump systole and diastole. Improvement in the dynamic response of the motor is very important to obtain better pump performance; this was accomplished by using power electronic simulation. For the motor to have the desired dynamic response, it must be commutated properly and the damping ratio (zeta), which represents transient characteristics of the motor, must lie between 0.4 and 0.8. Consequently, all satisfactory specifications with respect to power consumption must be obtained. Based on the simulated results, the design criteria were determined and the precise controller designed to reduce torque ripple and motor vibration, and determine motor stop time at every direction change. In in vitro tests, evaluation of the controller and dynamic response of the motor was justified in terms of zeta, power consumption, and motor stop time. The results indicated that the power consumption of the controller and the input power of the motor were decreased by 1.2 and 2.5 W at zeta = 0.6, respectively, compared to the previous system. An acceptable dynamic response of the motor, necessary for the reduction of torque ripple and motor vibration, was obtained between zeta = 0.5 and zeta = 0.7, with an increase in system efficiency from 10% to 12%. The motor stop time required for stable motor reoperation was determined to be over 10 msec, for a savings in power consumption of approximately 1.5 W. Therefore, the improved dynamic response of the motor can contribute to the stability and reliability of the pump.

Evaluation of antioxidant activity, total phenolics, total flavonoids and LC-MS/MS characterisation of phenolic constituents in Stachys lavandulifolia.

PubMed

Rahimi Khoigani, Soroush; Rajaei, Ahmad; Goli, Sayed Amir Hossein

2017-02-01

The aim of this study was to evaluate phenolics profile and antioxidant activity of Stachys lavandulifolia. Total phenolics (TP), total flavonoids (TF), DPPH• assay (IC50), ferric ion reducing antioxidant power (FRAP) and total antioxidant capacity (TAC) of the methanolic extract were measured. The content of TP, TF, IC50, FRAP and TAC, were obtained as 16.59 gallic acid equiv./g dry matter (DM), 4.48 mg quercetin equiv./g DM, 2.07 (μg/mL), 0.014 (absorbance/mg phenolic) and 14.61 (mg BHT equiv./g DM), respectively. The results showed that S. lavandulifolia, compared to other species of Stachys, had moderate TP content with desirable antioxidant activity. Subsequently, 59 various phenolic compounds were identified and confirmed in the methanolic extract of S. lavandulifolia using high mass accuracy by MS2 experiments. The compounds consisted of 6 hydroxybenzoic acids and hydroxybenzoic aldehydes, 9 hydroxycinnamic acids, 1 coumarin, 32 flavonoids, 3 lignans, 2 stilbenes, 3 tannins and 3 other phenolics.

Assessment on the Benefits from Energy Structure Optimization and Coal-fired Emission Control in Beijing: 1998-2013

NASA Astrophysics Data System (ADS)

Zong, Y.; He, K.; Zhang, Q.; Hong, C.

2016-12-01

Coal has long been an important energy type of Beijing's energy consumption. Since 1998, to improve urban air quality, Beijing has vigorously promoted the structure optimization of energy consumption. Primary measures included the implementation of strict emission standards for coal-fired power plant boilers, subsidized replacement and after-treatment retrofit of coal-fired boilers, the mandatory application of low-sulfur coal, and the accelerated use of natural gas, imported electricity and other clean energy. This work attempts to assess the emission reduction benefits on measures of three sectors, including replacing with clean energy and application of end-of-pipe control technologies in power plants, comprehensive control on coal-fired boilers and residential heating renovation. This study employs the model of Multi-resolution Emission Inventory for China (MEIC) to quantify emission reductions from upfront measures. These control measures have effectively reduced local emissions of major air pollutants in Beijing. The total emissions of PM2.5, PM10, SO2 and NOX from power plants in Beijing are estimated to have reduced 14.5 kt, 23.7 kt, 45.0 kt and 7.6 kt from 1998 to 2013, representing reductions of 86%, 87%, 85% and 16%, respectively. Totally, 14.3 kt, 24.0 kt, 136 kt and 48.7kt of PM2.5, PM10, SO2 and NOX emissions have been mitigated due to the comprehensive control measures on coal-fired boilers from 1998 to 2013. Residential heating renovation projects by replacing coal with electricity in Beijing's conventional old house areas contribute to emission reductions of 630 t, 870 t, 2070 t and 790 t for PM2.5, PM10, SO2 and NOX, respectively.

Methanolic extract of leaves of Jasminum grandiflorum Linn modulates oxidative stress and inflammatory mediators.

PubMed

Chaturvedi, Adya Prasad; Tripathi, Yamini Bhusan

2011-10-01

The leaves of Jasminum grandiflorum (JG) are in clinical use in Ayurveda for wound management. Since, oxidative stress and inflammation are the primary causes in delayed wound healing, so here its antioxidant and anti-inflammatory activities have been investigated using in vitro as well as in vivo models. The solvent-free methanolic extract of dried leaves of JG were tested for its trapping capacity toward pre-generated ABTS•+ radicals, instantly generated superoxide and hydroxyl radicals, along with metal chelation property, reducing power and total phenolic content. Further, it was tested on LPS-induced nitric oxide and cell viability, on primary culture of rat peritoneal macrophages. Its anti-inflammatory property was also tested on carrageenan-induced paw edema in rats. This extract significantly inhibited iron-induced lipid peroxidation and trapped ABTS•+, superoxide and OH radicals. It significantly inhibited nitric oxide (NO) release, without affecting the cell viability at 800 μg/ml concentration and reduced the formation of paw edema in rats. Thus, it could be suggested that the aforesaid anti-inflammatory properties of JG leaves are associated to its high phenolic content (2.25±0.105 mg/l of gallic acid equivalent), reducing power and its free radical-scavenging property.

Influence of template properties and quantum well number on stimulated emission from Al0.7Ga0.3N/Al0.8Ga0.2N quantum wells

NASA Astrophysics Data System (ADS)

Jeschke, J.; Martens, M.; Hagedorn, S.; Knauer, A.; Mogilatenko, A.; Wenzel, H.; Zeimer, U.; Enslin, J.; Wernicke, T.; Kneissl, M.; Weyers, M.

2018-03-01

AlGaN multiple quantum well laser heterostructures for emission around 240 nm have been grown by metalorganic vapor phase epitaxy on epitaxially laterally overgrown (ELO) AlN/sapphire templates. The edge emitting laser structures showed optically pumped lasing with threshold power densities in the range of 2 MW cm-2. The offcut angle of the sapphire substrates as well as the number and the width of the quantum wells were varied while keeping the total thickness of the gain region constant. A larger offcut angle of 0.2° leads to step bunching on the surface as well as Ga accumulation at the steps, but also to an increased inclination of threading dislocations and coalescence boundaries resulting in a reduced dislocation density and thus a reduced laser threshold in comparison to lasers grown on ELO with an offcut of 0.1°. For low losses, samples with fewer QWs exhibited a lower lasing threshold due to a reduced transparency pump power density while for high losses, caused by a higher threading dislocation density, the quadruple quantum well was favorable due to its higher maximum gain.

Modularized multilevel and z-source power converter as renewable energy interface for vehicle and grid-connected applications

NASA Astrophysics Data System (ADS)

Cao, Dong

Due the energy crisis and increased oil price, renewable energy sources such as photovoltaic panel, wind turbine, or thermoelectric generation module, are used more and more widely for vehicle and grid-connected applications. However, the output of these renewable energy sources varies according to different solar radiation, wind speed, or temperature difference, a power converter interface is required for the vehicle or grid-connected applications. Thermoelectric generation (TEG) module as a renewable energy source for automotive industry is becoming very popular recently. Because of the inherent characteristics of TEG modules, a low input voltage, high input current and high voltage gain dc-dc converters are needed for the automotive load. Traditional high voltage gain dc-dc converters are not suitable for automotive application in terms of size and high temperature operation. Switched-capacitor dc-dc converters have to be used for this application. However, high voltage spike and EMI problems exist in traditional switched-capacitor dc-dc converters. Huge capacitor banks have to be utilized to reduce the voltage ripple and achieve high efficiency. A series of zero current switching (ZCS) or zero voltage switching switched-capacitor dc-dc converters have been proposed to overcome the aforementioned problems of the traditional switched-capacitor dc-dc converters. By using the proposed soft-switching strategy, high voltage spike is reduced, high EMI noise is restricted, and the huge capacitor bank is eliminated. High efficiency, high power density and high temperature switched-capacitor dc-dc converters could be made for the TEG interface in vehicle applications. Several prototypes have been made to validate the proposed circuit and confirm the circuit operation. In order to apply PV panel for grid-connected application, a low cost dc-ac inverter interface is required. From the use of transformer and safety concern, two different solutions can be implemented, non-isolated or isolated PV inverter. For the non-isolated transformer-less solution, a semi-Z-source inverter for single phase photovoltaic systems has been proposed. The proposed semi-Z-source inverter utilizes only two switching devices with doubly grounded feature. The total cost have been reduced, the safety and EMI issues caused by the high frequency ground current are solved. For the transformer isolated solution, a boost half-bridge dc-ac micro-inverter has been proposed. The proposed boost half-bridge dc-dc converter utilizes only two switching devices with zero voltage switching features which is able to reduce the total system cost and power loss.

Manuka honey protects middle-aged rats from oxidative damage

PubMed Central

Jubri, Zakiah; Rahim, Noor Baitee Abdul; Aan, Goon Jo

2013-01-01

OBJECTIVE: This study aimed to determine the effect of manuka honey on the oxidative status of middle-aged rats. METHOD: Twenty-four male Sprague-Dawley rats were divided into young (2 months) and middle-aged (9 months) groups. They were further divided into two groups each, which were either fed with plain water (control) or supplemented with 2.5 g/kg body weight of manuka honey for 30 days. The DNA damage level was determined via the comet assay, the plasma malondialdehyde level was determined using high performance liquid chromatography, and the antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, glutathione peroxidase and catalase) were determined spectrophotometrically in the erythrocytes and liver. The antioxidant activities were measured using 1,1-diphenyl-2-picrylhydrazyl and ferric reducing/antioxidant power assays, and the total phenolic content of the manuka was analyzed using UV spectrophotometry and the Folin-Ciocalteu method, respectively. RESULTS: Supplementation with manuka honey reduced the level of DNA damage, the malondialdehyde level and the glutathione peroxidase activity in the liver of both the young and middle-aged groups. However, the glutathione peroxidase activity was increased in the erythrocytes of middle-aged rats given manuka honey supplementation. The catalase activity was reduced in the liver and erythrocytes of both young and middle-aged rats given supplementation. Manuka honey was found to have antioxidant activity and to have a high total phenolic content. These findings showed a strong correlation between the total phenolic content and antioxidant activity. CONCLUSIONS: Manuka honey reduces oxidative damage in young and middle-aged rats; this effect could be mediated through the modulation of its antioxidant enzyme activities and its high total phenolic content. Manuka honey can be used as an alternative supplement at an early age to improve the oxidative status. PMID:24270958

Manuka honey protects middle-aged rats from oxidative damage.

PubMed

Jubri, Zakiah; Rahim, Noor Baitee Abdul; Aan, Goon Jo

2013-11-01

This study aimed to determine the effect of manuka honey on the oxidative status of middle-aged rats. Twenty-four male Sprague-Dawley rats were divided into young (2 months) and middle-aged (9 months) groups. They were further divided into two groups each, which were either fed with plain water (control) or supplemented with 2.5 g/kg body weight of manuka honey for 30 days. The DNA damage level was determined via the comet assay, the plasma malondialdehyde level was determined using high performance liquid chromatography, and the antioxidant enzyme activities (superoxide dismutase, glutathione peroxidase, glutathione peroxidase and catalase) were determined spectrophotometrically in the erythrocytes and liver. The antioxidant activities were measured using 1,1-diphenyl-2-picrylhydrazyl and ferric reducing/antioxidant power assays, and the total phenolic content of the manuka was analyzed using UV spectrophotometry and the Folin-Ciocalteu method, respectively. Supplementation with manuka honey reduced the level of DNA damage, the malondialdehyde level and the glutathione peroxidase activity in the liver of both the young and middle-aged groups. However, the glutathione peroxidase activity was increased in the erythrocytes of middle-aged rats given manuka honey supplementation. The catalase activity was reduced in the liver and erythrocytes of both young and middle-aged rats given supplementation. Manuka honey was found to have antioxidant activity and to have a high total phenolic content. These findings showed a strong correlation between the total phenolic content and antioxidant activity. Manuka honey reduces oxidative damage in young and middle-aged rats; this effect could be mediated through the modulation of its antioxidant enzyme activities and its high total phenolic content. Manuka honey can be used as an alternative supplement at an early age to improve the oxidative status.

Power absorbed during whole-body vertical vibration: Effects of sitting posture, backrest, and footrest

NASA Astrophysics Data System (ADS)

Nawayseh, Naser; Griffin, Michael J.

2010-07-01

Previous studies have quantified the power absorbed in the seated human body during exposure to vibration but have not investigated the effects of body posture or the power absorbed at the back and the feet. This study investigated the effects of support for the feet and back and the magnitude of vibration on the power absorbed during whole-body vertical vibration. Twelve subjects were exposed to four magnitudes (0.125, 0.25, 0.625, and 1.25 m s -2 rms) of random vertical vibration (0.25-20 Hz) while sitting on a rigid seat in four postures (feet hanging, maximum thigh contact, average thigh contact, and minimum thigh contact) both with and without a rigid vertical backrest. Force and acceleration were measured at the seat, the feet, and the backrest to calculate the power absorbed at these three locations. At all three interfaces (seat, feet, and back) the absorbed power increased in proportion to the square of the magnitude of vibration, with most power absorbed from vibration at the seat. Supporting the back with the backrest decreased the power absorbed at the seat at low frequencies but increased the power absorbed at high frequencies. Supporting the feet with the footrest reduced the total absorbed power at the seat, with greater reductions with higher footrests. It is concluded that contact between the thighs and the seat increases the power absorbed at the seat whereas a backrest can either increase or decrease the power absorbed at the seat.

Spring-like Ankle Foot Orthoses reduce the energy cost of walking by taking over ankle work.

PubMed

Bregman, D J J; Harlaar, J; Meskers, C G M; de Groot, V

2012-01-01

In patients with central neurological disorders, gait is often limited by a reduced ability to push off with the ankle. To overcome this reduced ankle push-off, energy-storing, spring-like carbon-composite Ankle Foot Orthoses (AFO) can be prescribed. It is expected that the energy returned by the AFO in late stance will support ankle push-off, and reduce the energy cost of walking. In 10 patients with multiple sclerosis and stroke the energy cost of walking, 3D kinematics, joint power, and joint work were measured during gait, with and without the AFO. The mechanical characteristics of the AFO were measured separately, and used to calculate the contribution of the AFO to the ankle kinetics. We found a significant decrease of 9.8% in energy cost of walking when walking with the AFO. With the AFO, the range of motion of the ankle was reduced by 12.3°, and the net work around the ankle was reduced by 29%. The total net work in the affected leg remained unchanged. The AFO accounted for 60% of the positive ankle work, which reduced the total amount of work performed by the leg by 11.1% when walking with the AFO. The decrease in energy cost when walking with a spring-like energy-storing AFO in central neurological patients is not induced by an augmented net ankle push-off, but by the AFO partially taking over ankle work. Copyright © 2011 Elsevier B.V. All rights reserved.

Space power for space

NASA Technical Reports Server (NTRS)

Mullin, J. P.

1978-01-01

The total energy demanded by space missions of the future is expected to exceed past needs by orders of magnitude. The unit costs of this energy must be reduced from present levels if these missions are to be carried out at projected budget levels. The broad employment of electric propulsion and the capability to utilize novel high power sensors hinge on the availability of systems lighter by factors of ten or more than have flown to date. The NASA program aimed at providing the technological basis to meet these demands is described in this paper. Research and technology efforts in areas of energy conversion, storage and management are covered. In addition, work aimed at evolving the understanding necessary to cope with space environment interactions and at advanced concepts is described.

Logistics, Costs, and GHG Impacts of Utility-Scale Co-Firing with 20% Biomass

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

Nichol, Corrie Ian

This study analyzes the possibility that biopower in the U.S. is a cost-competitive option to significantly reduce greenhouse gas emissions. In 2009, net greenhouse gas (GHG) emitted in the United States was equivalent to 5,618 million metric tons CO 2, up 5.6% from 1990 (EPA 2011). Coal-fired power generation accounted for 1,748 million metric tons of this total. Intuitively, life-cycle CO 2 emissions in the power sector could be reduced by substituting renewable biomass for coal. If just 20% of the coal combusted in 2009 had been replaced with biomass, CO 2 emissions would have been reduced by 350 millionmore » metric tons, or about 6% of net annual GHG emission. This would have required approximately 225 million tons of dry biomass. Such an ambitious fuel substitution would require development of a biomass feedstock production and supply system tantamount to coal. This material would need to meet stringent specifications to ensure reliable conveyance to boiler burners, efficient combustion, and no adverse impact on heat transfer surfaces and flue gas cleanup operations. Therefore, this report addresses the potential cost/benefit tradeoffs of co-firing 20% specification-qualified biomass (on an energy content basis) in large U.S. coal-fired power plants. The dependence and sensitivity of feedstock cost on source of material, location, supply distance, and demand pressure was established. Subsequently, the dependence of levelized cost of electricity (LCOE) on feedstock costs, power plant feed system retrofit, and impact on boiler performance was determined. Overall life-cycle assessment (LCA) of greenhouse gas emissions saving were next evaluated and compared to wind and solar energy to benchmark the leading alternatives for meeting renewable portfolio standards (or RPS).« less

Integrating water use into Southern California's power dispatch: an evaluation of the potential for cost-effective water conservation

NASA Astrophysics Data System (ADS)

Bolorinos, J.; Ajami, N.; Yu, Y.; Rajagopal, R.

2016-12-01

Urban water supply and energy systems in the arid Southwestern United States are closely linked. Freshwater use by the electricity sector in particular represents a sizable portion of total water consumption in the region. Nonetheless, the dispatch of water and energy resources is managed separately, and no research to-date has examined the water conservation potential presented by the electricity sector. This study gauges the potential water savings that could be achieved including water use in the power dispatch process in Southern California by simulating a DC Optimal Power Flow for a simplified model of the region's power network. The simulation uses historical power consumption data, historical power production data and water use data from the US Geological Survey, the California Energy Commission and the US Energy Information Administration to estimate freshwater consumption by the region's thermoelectric power generation fleet. Preliminary results indicate that power system freshwater consumption could be reduced by as much as 20% at a minimal cost penalty, with potential for even greater savings. Model results show that Southern California's power system has the ability to competitively shift the use of some of the region's water resources from electricity to urban consumption, and suggests that water use should be incorporated into the policy-making process to enhance the efficient use of the state's interconnected water and energy resources.

An Inductively Powered Scalable 32-Channel Wireless Neural Recording System-on-a-Chip for Neuroscience Applications

PubMed Central

Lee, Seung Bae; Lee, Hyung-Min; Kiani, Mehdi; Jow, Uei-Ming; Ghovanloo, Maysam

2014-01-01

We present an inductively powered 32-channel wireless integrated neural recording (WINeR) system-on-a-chip (SoC) to be ultimately used for one or more small freely behaving animals. The inductive powering is intended to relieve the animals from carrying bulky batteries used in other wireless systems, and enables long recording sessions. The WINeR system uses time-division multiplexing along with a novel power scheduling method that reduces the current in unused low-noise amplifiers (LNAs) to cut the total SoC power consumption. In addition, an on-chip high-efficiency active rectifier with optimized coils help improve the overall system power efficiency, which is controlled in a closed loop to supply stable power to the WINeR regardless of the coil displacements. The WINeR SoC has been implemented in a 0.5-µm standard complementary metal–oxide semiconductor process, measuring 4.9 × 3.3 mm2 and consuming 5.85 mW at ± 1.5 V when 12 out of 32 LNAs are active at any time by power scheduling. Measured input-referred noise for the entire system, including the receiver located at 1.2 m, is 4.95 µVrms in the 1 Hz~10 kHz range when the system is inductively powered with 7-cm separation between aligned coils. PMID:23850753

Measurement of Fine Particles From Mobile and Stationary Sources, and Reducing the Air Conditioner Power Consumption in Hybrid Electric Vehicles

NASA Astrophysics Data System (ADS)

Brewer, Eli Henry

We study the PM2.5and ultrafine exhaust emissions from a new natural gas-fired turbine power facility to better understand air pollution in California. To characterize the emissions from new natural gas turbines, a series of tests were performed on a GE LMS100 gas turbine. These tests included PM2.5 and wet chemical tests for SO2/SO 3 and NH3, as well as ultrafine (less than 100 nm in diameter) particulate matter measurements. The turbine exhaust had an average particle number concentration that was 2.3x103 times higher than ambient air. The majority of these particles were nanoparticles; at the 100 nm size, stack particle concentrations were about 20 times higher than ambient, and increased to 3.9x104 times higher on average in the 2.5 - 3 nm particle size range. This study also found that ammonia emissions were higher than expected, but in compliance with permit conditions. This was possibly due to an ammonia imbalance entering the catalyst, some flue gas bypassing the catalyst, or not enough catalyst volume. SO3 accounted for an average of 23% of the total sulfur oxides emissions measured. Some of the SO3 is formed in the combustion process, it is likely that the majority formed as the SO2 in the combustion products passed across the oxidizing CO catalyst and SCR catalyst. The 100 MW turbine sampled in this study emitted particle loadings similar to those previously measured from turbines in the SCAQMD area, however, the turbine exhaust contained far more particles than ambient air. The power consumed by an air conditioner accounts for a significant fraction of the total power used by hybrid and electric vehicles especially during summer. This study examined the effect of recirculation of cabin air on power consumption of mobile air conditioners both in-lab and on-road. Real time power consumption and vehicle mileage were recorded by an On Board Diagnostic monitor and carbon balance method. Vehicle mileage improved with increased cabin air recirculation. The recirculation of cabin air also significantly reduced in-cabin particle concentrations. Recirculation of cabin air is an excellent and immediate solution to increase vehicle mileage and improve cabin air quality.

Performance of air-cathode stacked microbial fuel cells systems for wastewater treatment and electricity production.

PubMed

Estrada-Arriaga, Edson Baltazar; Guillen-Alonso, Yvonne; Morales-Morales, Cornelio; García-Sánchez, Liliana; Bahena-Bahena, Erick Obed; Guadarrama-Pérez, Oscar; Loyola-Morales, Félix

2017-07-01

Two different air-cathode stacked microbial fuel cell (MFC) configurations were evaluated under continuous flow during the treatment of municipal wastewater and electricity production at a hydraulic retention time (HRT) of 3, 1, and 0.5 d. Stacked MFC 1 was formed by 20 individual air-cathode MFC units. The second stacked MFC (stacked MFC 2) consisted of 40 air-cathode MFC units placed in a shared reactor. The maximum voltages produced at closed circuit (1,000 Ω) were 170 mV for stacked MFC 1 and 94 mV for stacked MFC 2. Different power densities in each MFC unit were obtained due to a potential drop phenomenon and to a change in chemical oxygen demand (COD) concentrations inside reactors. The maximum power densities from individual MFC units were up to 1,107 mW/m 2 for stacked MFC 1 and up to 472 mW/m 2 for stacked MFC 2. The maximum power densities in stacked MFC 1 and MFC 2 connected in series were 79 mW/m 2 and 4 mW/m 2 , respectively. Electricity generation and COD removal efficiencies were reduced when the HRT was decreased. High removal efficiencies of 84% of COD, 47% of total nitrogen, and 30% of total phosphorus were obtained during municipal wastewater treatment.

Modeling study of radiation characteristics with different impurity species seeding in EAST

NASA Astrophysics Data System (ADS)

Liu, X. J.; Deng, G. Z.; Wang, L.; Liu, S. C.; Zhang, L.; Li, G. Q.; Gao, X.

2017-12-01

A critical issue for EAST and future tokamak machines such as ITER and China Fusion Engineering Testing Reactor is the handling of excessive heat load on the divertor target plates. As an effective means of actively reducing and controlling the power fluxes to the target plates, localized impurity (N, Ne, and Ar) gas puffing from the lower dome is investigated by using SOLPS5.0 for an L-mode discharge on EAST with double null configuration. The radiative efficiency and distribution of different impurities are compared. The effect of N, Ne, and Ar seeding on target power load, the power entering into scrape-off layer (SOL), Psep, and their concentration in SOL along the poloidal length and edge effective ion charge number (Zeff) which are closely related to core plasma performance are presented. The simulation results indicate that N, Ne, and Ar seeding can effectively reduce the peak heat load and electron temperature at divertor targets similarly. N seeding can reach the highest radiative loss fraction and both N and Ar strongly radiate power in the divertor region, while the radiative power inside the separatrix for Ar seeding is also significant. Ne radiates power mainly around the separatrix and X-point. Ne and Ar impurities' puffing results in a faster decrease of Psep than N seeding case; the reduction of Psep can eventually degrade the core performance of fusion plasma. Additionally, seeding with Ne has a totally larger concentration at the outer midplane and edge Zeff than those in N and Ar seeding cases; it suggests that N and Ar impurities are more acceptable than Ne in terms of fuel dilution for this discharge.

Formation, characterization, aggregation, fluorescence and antioxidant properties of novel tetrasubstituted metal-free and metallophthalocyanines bearing (4-(methylthio)phenoxy) moieties

NASA Astrophysics Data System (ADS)

Yıldırım, Nurdan; Bilgiçli, Ahmet T.; Alici, Esma Hande; Arabacı, Gulnur; Yarasir, M. Nilüfer

2017-09-01

The synthesis and characterization of peripherally tetra 4-(methylthio)phenoxy substituted metal-free(2), Zn(II) (3) and Co(II) (4) phthalocyanine derivatives were reported. These newly synthesized phthalocyanine derivatives showed the enhanced solubility in organic solvents and they were characterized by a combination of elemental analysis, FTIR, 1H NMR, 13C NMR, UV-vis and MALDI-TOF/MS spectral data. Their aggregation properties were investigated in THF by UV-vis and fluorescence. These metal-free and metallophthalocyanine compounds were also evaluated for their total antioxidant abilities by using three different antioxidant methods such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging, ferrous ion chelating and reducing power activity. All tested compounds showed radical scavenging activity. The highest radical scavenging activity was found from cobalt phthalocyanine (4) compound respectively. IC50 values of the compounds and standards (BHT and Trolox) were also determined. The results showed that the compound 4 had the highest antioxidant activity among all tested compounds including standards. The tested phthalocyanine compounds had ferrous ion chelating activity. In addition, they showed very high reducing power. All tested compounds had higher reducing power than the standards such as ascorbic acid and BHT. The present study shows that the synthesized tetra phthalocyanine [M: 2H(2), Zn(II)(3), Co(II)(4)] with four peripheral 4-(methylthio) phenoxy compounds have the effective antioxidant properties that can be used as antioxidant agents.

Anti-acetylcholinesterase activity and antioxidant properties of extracts and fractions of Carpolobia lutea.

PubMed

Nwidu, Lucky Legbosi; Elmorsy, Ekramy; Thornton, Jack; Wijamunige, Buddhika; Wijesekara, Anusha; Tarbox, Rebecca; Warren, Averil; Carter, Wayne Grant

2017-12-01

There is an unmet need to discover new treatments for Alzheimer's disease. This study determined the anti-acetylcholinesterase (AChE) activity, DPPH free radical scavenging and antioxidant properties of Carpolobia lutea G. Don (Polygalaceae). The objective of this study is to quantify C. lutea anti-AChE, DPPH free radical scavenging, and antioxidant activities and cell cytotoxicity. Plant stem, leaves and roots were subjected to sequential solvent extractions, and screened for anti-AChE activity across a concentration range of 0.02-200 μg/mL. Plant DPPH radical scavenging activity, reducing power, and total phenolic and flavonoid contents were determined, and cytotoxicity evaluated using human hepatocytes. Carpolobia lutea exhibited concentration-dependent anti-AChE activity. The most potent inhibitory activity for the stem was the crude ethanol extract and hexane stem fraction oil (IC 50  = 140 μg/mL); for the leaves, the chloroform leaf fraction (IC 50  = 60 μg/mL); and for roots, the methanol, ethyl acetate and aqueous root fractions (IC 50  = 0.3-3 μg/mL). Dose-dependent free radical scavenging activity and reducing power were observed with increasing stem, leaf or root concentration. Total phenolic contents were the highest in the stem: ∼632 mg gallic acid equivalents/g for a hexane stem fraction oil. Total flavonoid content was the highest in the leaves: ∼297 mg quercetin equivalents/g for a chloroform leaf fraction. At 1 μg/mL, only the crude ethanol extract oil was significantly cytotoxic to hepatocytes. Carpolobia lutea possesses anti-AChE activity and beneficial antioxidant capacity indicative of its potential development as a treatment of Alzheimer's and other diseases characterized by a cholinergic deficit.

In vitro antioxidant potential of dicliptera roxburghiana

PubMed Central

2013-01-01

Background Stress caused by free radicals accumulation result into many hazardous diseases. A number of investigations are focusing to find out the plant oriented natural antioxidant moieties. The basic aim of this research was to investigate the antioxidant potential, total Phenolic and flavonoids contents and photochemical screening of the crude methanol extract and its derived various fractions Dicliptera roxburghiana of Acanthaceae family. Methods Crude methanol extract of aerial parts of Dicliptera roxburghiana (DRME) was partitioned in to n-hexane (DRHF), chloroform (DRCF), ethyl acetate (DREF), n-butanol (DRBF) and the remaining soluble portion as residual aqueous fraction (DRAF). We evaluated the antioxidant activities of the extract and various fractions through different analytical methods such as DPPH, superoxide anion, ABTS, H2O2, hydroxyl radical and phosphomolybdate radical inhibition. In vitro lipid peroxidation and reducing power of the plant was also analyzed. Total flavonoid and phenolic contents of the extract and all fractions were also quantified. Plant was also subjected for preliminary phytochemical screening to confirm the presence or absence of various constituents in the plant. Results Phytochemical screening confirmed the presence of flavonoids, phenolics, tannins, alkaloids, saponins, terpenoids and coumarines. Quantitative analysis revealed the maximum amount of total phenolic and flavonoid contents in DRME while lowest in DRHF. Methanol extract, DREF, DRCF and DRBF exhibited promising antioxidant potential for DPPH, ABTS, H2O2, phosphomolybdate, superoxide anion and hydroxyl radical scavenging capabilities, while these were not appreciable for DRHF and DRAF. All fractions except DRHF and DRAF possess strong reducing power ability and showed appreciable lipid peroxidation inhibition. Conclusion These research investigations revealed that Dicliptera roxburghiana is a potent source of natural antioxidants. Hence the plant can be used for management of different stress and anxiety related ailments. PMID:23777321

Melilotus albus and Dorycnium herbaceum extracts as source of phenolic compounds and their antimicrobial, antibiofilm, and antioxidant potentials.

PubMed

Stefanović, Olgica D; Tešić, Jelena D; Čomić, Ljiljana R

2015-09-01

Melilotus albus Medic. and Dorycnium herbaceum Vill. (Fabaceae) acetone, ethyl acetate, and ethanol extracts were investigated for their in vitro antimicrobial, antibiofilm, and antioxidant activity with quantification of phenolic compound contents. In general, D. herbaceum extracts showed better antibacterial and antioxidant activity than M. albus extracts. Bacteria Bacillus subtilis, Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa, and Proteus mirabilis were the most susceptible with the minimum inhibitory concentrations (MICs), determined by microdilution method, between 1.25-10 mg/mL. Antifungal activity was lower with the detectable MICs at 10 mg/mL and 20 mg/mL. The plant extracts, using the crystal violet assay, inhibit P. aeruginosa biofilm formation in concentration range from 5 mg/mL to 20 mg/mL whereas the effect on mature bacterial biofilm was lower. The antioxidant activity was evaluated using 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging and reducing power model systems. The intensity of DPPH radicals scavenging activity, expressed as half maximal effective concentration (EC 50 ) values, was from 84.33 μg/mL to >1000 μg/mL. The extracts demonstrated reduced power in a concentration-dependent manner, with ethanol extract as the most active. The total phenols, flavonoids, and proanthocyanidins were determined spectrophotometrically while total extractable tannins were obtained by precipitation method. The phenolic compounds showed differences in their total contents depending on solvents polarities and plant species. Although the plants M. albus and D. herbaceum have not yet been fully explored, these results contribute better understanding of their biotic properties and potential application as antimicrobial and antioxidant agents. Copyright © 2015. Published by Elsevier B.V.

Phenolic composition, antioxidant and anti-acetylcholinesterase activities of the Tunisian Scabiosa arenaria.

PubMed

Besbes Hlila, Malek; Omri, Amel; Ben Jannet, Hichem; Lamari, Ali; Aouni, Mahjoub; Selmi, Boulbaba

2013-05-01

There is a need for the discovery of novel natural antioxidants and acetylcholinesterase inhibitors (AChEIs) that are safe and effective at a global level. This is the first study on antioxidant and anti-acethylcholinesterase activity of Scabiosa arenaria Forssk (Dipsacaceae). The antioxidant potential and anti-acetylcholinesterase (AChE) activity of S. arenaria were investigated. The crude, ethyl acetate (EtOAc), butanol (n-BuOH) and water extracts prepared from flowers, fruits and stems and leaves of S. arenaria were tested to determine their total polyphenol content (TPC), total flavonoid content (TFC), total condensed tannin content (CTC) and their antioxidant activity by using 1,1-diphenyl-2-picrylhydrazyl (DPPH), 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS), reducing power and β-carotene bleaching inhibition activity. Anti-AChE activity was also determined. EtOAc and n-BuOH fractions of fruits had both the highest (TPC) (269.09 mg gallic acid equivalents/g dry weight). The crude extract of stems and leaves had the highest TFC (10.9 mg quercetin equivalent/g dry weight). The n-BuOH fraction of stems and leaves had the highest CTC (489.75 mg catechin equivalents/g dry weight). The EtOAc fraction of flowers exhibit a higher activity in each antioxidant system with a special attention for DPPH assay (IC50 = 0.017 mg/mL) and reducing power (EC50 = 0.02 mg/mL). The EtOAc and n-BuOH fractions of stems and leaves showed strong inhibition of AChE (IC50 = 0.016 and 0.029 mg/mL, respectively). These results suggest the potential of S. arenaria as a possible source of novel compounds and as an alternative antioxidant and AChEIs.

Power distance and mentor-protégé relationship quality as moderators of the relationship between informal mentoring and burnout: evidence from China.

PubMed

Qian, Jing; Han, Zhuo; Wang, Haiwan; Li, Xiaoyan; Wang, Qiuyue

2014-01-01

The topic of how to prevent and reduce burnout has drawn great attention from researchers and practitioners in recent years. However, we know little about how mentoring as a form of social support exerts influence on employee burnout. This study aims to examine the contingency side of the mentoring-burnout relationship by addressing the exploratory question of whether individual differences in power distance and relationship quality play important roles in mentoring effectiveness in terms of reducing a protégé's burnout level. A total of 210 employees from a technology communications company completed the survey questionnaire. (1) A protégés' power distance moderates the negative relationship between mentoring and burnout in such a way that the relationship is stronger for protégés who are lower rather than higher in power distance; (2) mentor-protégé relationship quality moderates the negative relationship between mentoring and burnout in such a way that the relationship is stronger when the relationship quality is higher rather than lower. In sum, our results highlight the importance of studying the contingency side of mentoring effects on protégé burnout. Our findings suggest that the individuals' different cultural values of power distance and mentor-protégé relationship quality are the boundary conditions for the mentoring-burnout relationship. We therefore suggest that research on mentoring-burnout will be advanced by considering the role of the moderating process.

Influence of Forecast Accuracy of Photovoltaic Power Output on Capacity Optimization of Microgrid Composition under 30 min Power Balancing Control

NASA Astrophysics Data System (ADS)

Sone, Akihito; Kato, Takeyoshi; Shimakage, Toyonari; Suzuoki, Yasuo

A microgrid (MG) is one of the measures for enhancing the high penetration of renewable energy (RE)-based distributed generators (DGs). If a number of MGs are controlled to maintain the predetermined electricity demand including RE-based DGs as negative demand, they would contribute to supply-demand balancing of whole electric power system. For constructing a MG economically, the capacity optimization of controllable DGs against RE-based DGs is essential. By using a numerical simulation model developed based on a demonstrative study on a MG using PAFC and NaS battery as controllable DGs and photovoltaic power generation system (PVS) as a RE-based DG, this study discusses the influence of forecast accuracy of PVS output on the capacity optimization. Three forecast cases with different accuracy are compared. The main results are as follows. Even with no forecast error during every 30 min. as the ideal forecast method, the required capacity of NaS battery reaches about 40% of PVS capacity for mitigating the instantaneous forecast error within 30 min. The required capacity to compensate for the forecast error is doubled with the actual forecast method. The influence of forecast error can be reduced by adjusting the scheduled power output of controllable DGs according to the weather forecast. Besides, the required capacity can be reduced significantly if the error of balancing control in a MG is acceptable for a few percentages of periods, because the total periods of large forecast error is not so often.

Depressed mood, positive affect, and heart rate variability in patients with suspected coronary artery disease.

PubMed

Bhattacharyya, Mimi R; Whitehead, Daisy L; Rakhit, Roby; Steptoe, Andrew

2008-11-01

To test associations between heart rate variability (HRV), depressed mood, and positive affect in patients with suspected coronary artery disease (CAD). Depression is associated with impaired HRV post acute cardiac events, but evidence in patients with stable coronary artery disease (CAD) is inconsistent. Seventy-six patients (52 men, 24 women; mean age = 61.1 years) being investigated for suspected CAD on the basis of symptomatology and positive noninvasive tests, completed 24-hour electrocardiograms. The Beck Depression Inventory (BDI) was administered, and positive and depressed affect was measured over the study period with the Day Reconstruction Method (DRM). A total of 46 (60.5%) patients were later found to have definite CAD. HRV was analyzed, using spectral analysis. Typical diurnal profiles of HRV were observed, with greater normalized high frequency (HF) and lower normalized low frequency (LF) power in the night compared with the day. BDI depression scores were not consistently associated with HRV. But positive affect was associated with greater normalized HF power (p = .039) and reduced normalized LF power (p = .007) independently of age, gender, medication with beta blockers, CAD status, body mass index, smoking, and habitual physical activity level. In patients with definite CAD, depressed affect assessed using the DRM was associated with reduced normalized HF power and heightened normalized LF power (p = .007) independently of covariates. Relationships between depression and HRV in patients with CAD may depend on affective experience over the monitoring period. Enhanced parasympathetic cardiac control may be a process through which positive affect protects against cardiovascular disease.

A Distributed Data-Gathering Protocol Using AUV in Underwater Sensor Networks.

PubMed

Khan, Jawaad Ullah; Cho, Ho-Shin

2015-08-06

In this paper, we propose a distributed data-gathering scheme using an autonomous underwater vehicle (AUV) working as a mobile sink to gather data from a randomly distributed underwater sensor network where sensor nodes are clustered around several cluster headers. Unlike conventional data-gathering schemes where the AUV visits either every node or every cluster header, the proposed scheme allows the AUV to visit some selected nodes named path-nodes in a way that reduces the overall transmission power of the sensor nodes. Monte Carlo simulations are performed to investigate the performance of the proposed scheme compared with several preexisting techniques employing the AUV in terms of total amount of energy consumption, standard deviation of each node's energy consumption, latency to gather data at a sink, and controlling overhead. Simulation results show that the proposed scheme not only reduces the total energy consumption but also distributes the energy consumption more uniformly over the network, thereby increasing the lifetime of the network.

A Distributed Data-Gathering Protocol Using AUV in Underwater Sensor Networks

PubMed Central

Khan, Jawaad Ullah; Cho, Ho-Shin

2015-01-01

In this paper, we propose a distributed data-gathering scheme using an autonomous underwater vehicle (AUV) working as a mobile sink to gather data from a randomly distributed underwater sensor network where sensor nodes are clustered around several cluster headers. Unlike conventional data-gathering schemes where the AUV visits either every node or every cluster header, the proposed scheme allows the AUV to visit some selected nodes named path-nodes in a way that reduces the overall transmission power of the sensor nodes. Monte Carlo simulations are performed to investigate the performance of the proposed scheme compared with several preexisting techniques employing the AUV in terms of total amount of energy consumption, standard deviation of each node’s energy consumption, latency to gather data at a sink, and controlling overhead. Simulation results show that the proposed scheme not only reduces the total energy consumption but also distributes the energy consumption more uniformly over the network, thereby increasing the lifetime of the network. PMID:26287189

Evaluation of antioxidant capacity of Chinese five-spice ingredients.

PubMed

Bi, Xinyan; Soong, Yean Yean; Lim, Siang Wee; Henry, Christiani Jeyakumar

2015-05-01

Phenolic compounds in spices were reportedly found to possess high antioxidant capacities (AOCs), which may prevent or reduce risk of human diseases such as cardiovascular disease, cancer and diabetes. The potential AOC of Chinese five-spice powder (consist of Szechuan pepper, fennel seed, cinnamon, star anise and clove) with varying proportion of individual spice ingredients was investigated through four standard methods. Our results suggest that clove is the major contributor to the AOC of the five-spice powder whereas the other four ingredients contribute to the flavour. For example, the total phenolic content as well as ferric reducing antioxidant power (FRAP), Trolox equivalent antioxidant capacity (TEAC) and oxygen radical absorbance capacity (ORAC) values increased linearly with the clove percentage in five-spice powder. This observation opens the door to use clove in other spice mixtures to increase their AOC and flavour. Moreover, linear relationships were also observed between AOC and the total phenolic content of the 32 tested spice samples.

Analysis and characterisation of phytochemicals in mulberry (Morus alba L.) fruits grown in Vojvodina, North Serbia.

PubMed

Natić, Maja M; Dabić, Dragana Č; Papetti, Adele; Fotirić Akšić, Milica M; Ognjanov, Vladislav; Ljubojević, Mirjana; Tešić, Živoslav Lj

2015-03-15

In this study, the polyphenolic profile of 11 Morus alba fruits grown in the Vojvodina region was investigated. Ultra high performance liquid chromatography (UHPLC) coupled with Linear Trap Quadrupole and OrbiTrap mass analyzer, and UHPLC coupled with a diode array detector and a triple-quadrupole mass spectrometer were used for the identification and quantification of the polyphenols, respectively. A total of 14 hydroxycinnamic acid esters, 13 flavonol glycosides, and 14 anthocyanins were identified in the extracts with different distributions and contents according to the sampling. The total phenolic content ranged from 43.84 to 326.29 mg GAE/100g frozen fruit. The radical scavenging capacity (50.18-86.79%), metal chelating ability (0.21-8.15%), ferric ion reducing power (0.03-38.45 μM ascorbic acid) and superoxide anion radical scavenging activity (16.53-62.83%) were assessed. The findings indicated that mulberry polyphenolics may act as potent superoxide anion radical scavengers and reducing agents. Copyright © 2014 Elsevier Ltd. All rights reserved.

A novel source of biofertilizer from feather biomass for banana cultivation.

PubMed

Gurav, Ranjit G; Jadhav, Jyoti P

2013-07-01

Feather waste is a promising protein biomass available as by-product from poultry processing was found to be rich in peptides, amino acids, and minerals like nitrogen, phosphorus, potassium, calcium, magnesium, iron, manganese, zinc, and copper. Soil and foliar application of these products, besides representing a sustainable solution to the problem of feather disposal, may also represent an effective strategy to tackle the environmental effluence. As a consequence, they were also found to be very attractive in elevating the protein, amino acids, reducing sugar, total chlorophyll, and proline content of plants. On the other side, fertilizing effect enhanced the antioxidant potential of banana fruit which was assessed using 2, 2-diphenyl-1-picrylhydrazyl, ferric reducing/antioxidant power, and N, N-dimethyl-p-phenylendiamine. This was associated with considerably higher antioxidant contents like total phenolics and flavonoids. Therefore, the application of this organic amendment could promote and improve the agro-ecosystem, human health; soil biological activities, and at the same time enhance the production of plant or products rich in bioactive substances.

Co-twin control designs for testing behavioral economic theories of child nutrition: methodological note.

PubMed

Faith, M S; Rose, E; Matz, P E; Pietrobelli, A; Epstein, L H

2006-10-01

To illustrate the use and potential efficiency of the co-twin control design for testing behavioral economic theories of child nutrition. Co-twin control design, in which participating twins ate an ad libitum lunch on two laboratory visits. At visit 1, child food choices were not reinforced. On visit 2, twins were randomized to conditions such that one twin was reinforced for each fruit and vegetable serving consumed during lunch ('contingent') while his co-twin was reinforced irrespective of food intake ('non-contingent'). Six male twins, 5 years old, from three monozygotic twin pairs. Ad libitum intake of total energy (kcals), fat (kcals), and fruits and vegetables (servings) from the protocol test meals on the two visits. Compared to twins receiving non-contingent reinforcement, twins receiving contingent reinforcement increased fruit and vegetable intake by 2.0 servings, reduced fat intake 106.3 kcals, and reduced total energy intake by 112.7 kcals. The relative efficiency of the co-twin control design compared to a conventional between-groups design of unrelated children was most powerful for detecting 'substitution effects' (i.e., reduced total energy and fat intake) more so than for detecting increased fruit and vegetable intake. Genetically informative studies, including the co-twin control design, can provide conceptually elegant and efficient strategies for testing environmental theories of child nutrition and obesity.

Effect of extraction solvents on the biomolecules and antioxidant properties of Scorzonera undulata (Asteraceae): Application of factorial design optimization phenolic extraction.

PubMed

Athmouni, Khaled; Belghith, Taheni; Bellassouad, Khaled; Feki, Abdelfattah El; Ayadi, Habib

2015-01-01

Phenolic compounds were extracted and isolated from S. undulata roots. Sample of roots from E. hirta was tested for phenolic compounds, and in vitro antioxidant activity by diphenyl-1-picrylhydrazyl (DPPH) assay, ABTS, FRAP and reducing power was measured using cyano- ferrate method. The methanolic fraction exhibited the highest total phenol content (6.12 ±0.11 mg AGE/g DW). On the other hand, the highest flavonoids concentration was observed in ethyl acetate fraction (2.90 ±0.05 mg CE/g DW) in addition to anthocyanins (28.56 ±3.96 mg/l). Besides, the highest level of tannins content was measured in the polar aprotic solvent ethyl acetate extract (3.25 ±0.06 mg CE/g DW). The different extracts of S. undulata were evaluated for their radical scavenging activities by means of the DPPH assay. The strongest scavenging activity was observed in methanolic fraction scavenged radicals effectively with IC   values of 0.14 ±0.02 mg/ml. Similarly, the potassium ferricyanide reduction (FRAP) and ABTS•+ of methanol extract. On the other hand, the total reducing power of ethyl acetate extract was found higher than of other extracts. This paper presents the application of the design-of experiment method for optimizing the extraction of phenolic content using methanol solvent. The resulting regression model has shown that the effect of temperature is not statistically significant (with >95% certainty), while that of agitation speed is. The two main effects are contributed by the solvent concentration and the maceration period. Our results clearly showed that the extraction of phenolic compounds and their antioxidant capacity is significantly affected by solvent combinations. S. undulata presented the highest total phenolic content, total flavonoids content and antioxidant capacity values. The resulting regression model has shown that the effect of temperature is not statistically significant (with >95% certainty), while that of agitation speed is.

Towards further understanding on the antioxidative activities of Prunus persica fruit: A comparative study with four different fractions

NASA Astrophysics Data System (ADS)

Dhingra, Naveen; Sharma, Rajesh; Kar, Anand

2014-11-01

In the present study we have evaluated the antioxidant activities of different fractions (hexane, ethyl acetate, n-butanol and aqueous fractions) of Prunus persica fruit. For extraction simple warring blender method was employed and total phenolic and flavonoid contents were correlated with different antioxidant activities (total antioxidant, 2,2-diphenyl-1-picrylhydrazyl (DPPH), H2O2 scavenging, superoxide radical scavenging, iron chelating and their reducing power properties). Different in vitro antioxidant studies showed that ethyl acetate and n-butanol fractions had the maximum activities that were well correlated with total phenolic and flavonoid contents. Maximum yield (25.14 ± 2.2%) was obtained in its aqueous fraction. Both ethyl acetate and n-butanol fractions showed significant inhibitory effects on different antioxidant activities. A significantly high correlation coefficient existed between total antioxidant activities and with total phenolic as well as total flavonoid contents. It appears that ethyl acetate and n-butanol fractions of P. persica may serve as new potential sources of natural antioxidants and could be of therapeutic use in treating several diseases.

A quality improvement management model for renal care.

PubMed

Vlchek, D L; Day, L M

1991-04-01

The purpose of this article is to explore the potential for applying the theory and tools of quality improvement (total quality management) in the renal care setting. We believe that the coupling of the statistical techniques used in the Deming method of quality improvement, with modern approaches to outcome and process analysis, will provide the renal care community with powerful tools, not only for improved quality (i.e., reduced morbidity and mortality), but also for technology evaluation and resource allocation.

The position of gas turbine power plants with respect to the emission of nitrogen oxides by fossil-fueled energy installations

NASA Technical Reports Server (NTRS)

Kaiser, E.

1977-01-01

The amount of nitrogen oxides introduced into the atmosphere by gas turbines is very significant in relation to the total amount of nitrogen oxide emissions produced by chemical installations and combustion engines. Turbine manufacturers are therefore working to develop combustion chambers with sufficiently low nitrogen oxide emission concentrations. Attention is given to aspects of nitrogen oxide formation in gas turbines, the parameters which determine this formation, and suitable approaches to reducing nitrogen oxide emissions.

26 CFR 1.423-2 - Employee stock purchase plan defined.

Code of Federal Regulations, 2010 CFR

2010-04-01

... employee owns stock possessing 5 percent or more of the total combined voting power or value of all classes... granted, owns stock possessing 5 percent or more of the total combined voting power or value of all... the percentage of the total combined voting power or value of all classes of stock of the employer...

The power of cross-functional teams in driving total quality

NASA Astrophysics Data System (ADS)

McClung, Tim M.; McMaster, Tom J.

Garrett Canada, a Division of Allied-Signal Aerospace Canada, has been a member of the Canadian aerospace industry for 40 years. Although Garrett Canada has always been a profitable division with a solid market share, the changing and turbulent business environment and globalization of the aerospace industry has created new demands and challenges. The marketplace is demanding faster introduction of new products, as well as shorter leadtimes for repairs and spares. It was recognized that reducing cycle times for new products and for ongoing production would not only satisfy our customers, it would also enhance our business performance through reduced inventories, lower past due, and more responsiveness to change. It was evident that drastic function changes were required if we were to maintain our position as a premier aerospace supplier. The challenge was to convert a stable, somewhat slow-paced work environment with strong functional boundaries into a boundaryless world class team functioning in a total quality environment and focused on customer satisfaction. Complete and uncompromised customer satisfaction has become our driving force, with Total Quality being our engine to continuously improve our processes and increase our speed. The way in which this transition has been brought about is the subject of this presentation.

Impact of optimised cooking on the antioxidant activity in edible mushrooms.

PubMed

Ng, Zhi Xiang; Tan, Wan Chein

2017-11-01

This study aimed to investigate the effect of four cooking methods with different durations on the in vitro antioxidant activities of five edible mushrooms, namely Agaricus bisporus , Flammulina velutipes , Lentinula edodes , Pleurotus ostreatus and Pleurotus eryngii. Among the raw samples, A. bisporus showed the highest total antioxidant activity (reducing power and radical scavenging), total flavonoid, ascorbic acid and water soluble phenolic contents. Short-duration steam cooking (3 min) increased the total flavonoid and ascorbic acid while prolonged pressure cooking (15 min) reduced the water soluble phenolic content in the mushrooms. The retention of antioxidant value in the mushrooms varied with the variety of mushroom after the cooking process. The cooking duration significantly affected the ascorbic acid in the mushrooms regardless of cooking method. To achieve the best antioxidant values, steam cooking was preferred for F. velutipes (1.5 min), P. ostreatus (4.5 min) and L. edodes (4.5 min) while microwave cooking for 1.5 min was a better choice for A. bisporus . Pressure cooked P. eryngii showed the best overall antioxidant value among the cooked samples. Optimised cooking method including pressure cooking could increase the antioxidant values in the edible mushrooms.

Physicochemical and antioxidant properties of black garlic.

PubMed

Choi, Il Sook; Cha, Han Sam; Lee, Young Soon

2014-10-20

Black garlic (BG) is a processed garlic product prepared by heat treatment of whole garlic bulbs (Allium sativum L.) at high temperature under high humidity for several days, resulting in black cloves with a sweet taste. BG has recently been introduced to the Korean market as a product beneficial to health. To clarify how BG changes during the 35 day aging period, the physicochemical characteristics, antioxidant contents, and antioxidant activities were evaluated under controlled conditions of 70 °C and 90% relative humidity. Reducing sugar and total acidity of BG increased during the aging period, whereas pH decreased from pH 6.33 to 3.74. Lightness and yellowness values of BG radically decreased during the aging period, whereas redness values increased significantly. Antioxidant components, including the total polyphenol and total flavonoids contents of BG, increased significantly until the 21st day of aging (p < 0.05) and correspondingly, the antioxidant activities of BG, measured by DPPH, ABTS, FRAP, and reducing power assays, were highest on the 21st day of aging. These results indicate that BG can be considered to not only possess antioxidant properties during the aging period, but also to reach its optimal antioxidant properties at the 21st day of aging.

The power of cross-functional teams in driving total quality

NASA Technical Reports Server (NTRS)

Mcclung, Tim M.; Mcmaster, Tom J.

1992-01-01

Garrett Canada, a Division of Allied-Signal Aerospace Canada, has been a member of the Canadian aerospace industry for 40 years. Although Garrett Canada has always been a profitable division with a solid market share, the changing and turbulent business environment and globalization of the aerospace industry has created new demands and challenges. The marketplace is demanding faster introduction of new products, as well as shorter leadtimes for repairs and spares. It was recognized that reducing cycle times for new products and for ongoing production would not only satisfy our customers, it would also enhance our business performance through reduced inventories, lower past due, and more responsiveness to change. It was evident that drastic function changes were required if we were to maintain our position as a premier aerospace supplier. The challenge was to convert a stable, somewhat slow-paced work environment with strong functional boundaries into a boundaryless world class team functioning in a total quality environment and focused on customer satisfaction. Complete and uncompromised customer satisfaction has become our driving force, with Total Quality being our engine to continuously improve our processes and increase our speed. The way in which this transition has been brought about is the subject of this presentation.

Power management system

DOEpatents

Algrain, Marcelo C.; Johnson, Kris W.; Akasam, Sivaprasad; Hoff, Brian D.

2007-10-02

A method of managing power resources for an electrical system of a vehicle may include identifying enabled power sources from among a plurality of power sources in electrical communication with the electrical system and calculating a threshold power value for the enabled power sources. A total power load placed on the electrical system by one or more power consumers may be measured. If the total power load exceeds the threshold power value, then a determination may be made as to whether one or more additional power sources is available from among the plurality of power sources. At least one of the one or more additional power sources may be enabled, if available.

Device Access Abstractions for Resilient Information Architecture Platform for Smart Grid

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

Dubey, Abhishek; Karsai, Gabor; Volgyesi, Peter

An open application platform distributes the intelligence and control capability to local endpoints (or nodes) reducing total network traffic, improving speed of local actions by avoiding latency, and improving reliability by reducing dependencies on numerous devices and communication interfaces. The platform must be multi-tasking and able to host multiple applications running simultaneously. Given such a system, the core functions of power grid control systems include grid state determination, low level control, fault intelligence and reconfiguration, outage intelligence, power quality measurement, remote asset monitoring, configuration management, power and energy management (including local distributed energy resources, such as wind, solar and energymore » storage) can be eventually distributed. However, making this move requires extensive regression testing of systems to prove out new technologies, such as phasor measurement units (PMU). Additionally, as the complexity of the systems increase with the inclusion of new functionality (especially at the distribution and consumer levels), hidden coupling issues becomes a challenge with possible N-way interactions known and not known by device and application developers. Therefore, it is very important to provide core abstractions that ensure uniform operational semantics across such interactions. Here in this paper, we describe the pattern for abstracting device interactions we have developed for the RIAPS platform in the context of a microgrid control application we have developed.« less

Device Access Abstractions for Resilient Information Architecture Platform for Smart Grid

DOE PAGES

Dubey, Abhishek; Karsai, Gabor; Volgyesi, Peter; ...

2018-06-12

An open application platform distributes the intelligence and control capability to local endpoints (or nodes) reducing total network traffic, improving speed of local actions by avoiding latency, and improving reliability by reducing dependencies on numerous devices and communication interfaces. The platform must be multi-tasking and able to host multiple applications running simultaneously. Given such a system, the core functions of power grid control systems include grid state determination, low level control, fault intelligence and reconfiguration, outage intelligence, power quality measurement, remote asset monitoring, configuration management, power and energy management (including local distributed energy resources, such as wind, solar and energymore » storage) can be eventually distributed. However, making this move requires extensive regression testing of systems to prove out new technologies, such as phasor measurement units (PMU). Additionally, as the complexity of the systems increase with the inclusion of new functionality (especially at the distribution and consumer levels), hidden coupling issues becomes a challenge with possible N-way interactions known and not known by device and application developers. Therefore, it is very important to provide core abstractions that ensure uniform operational semantics across such interactions. Here in this paper, we describe the pattern for abstracting device interactions we have developed for the RIAPS platform in the context of a microgrid control application we have developed.« less

Microwave flow and conventional heating effects on the physicochemical properties, bioactive compounds and enzymatic activity of tomato puree.

PubMed

Arjmandi, Mitra; Otón, Mariano; Artés, Francisco; Artés-Hernández, Francisco; Gómez, Perla A; Aguayo, Encarna

2017-02-01

Thermal processing causes a number of undesirable changes in physicochemical and bioactive properties of tomato products. Microwave (MW) technology is an emergent thermal industrial process that offers a rapid and uniform heating, high energy efficiency and high overall quality of the final product. The main quality changes of tomato puree after pasteurization at 96 ± 2 °C for 35 s, provided by a semi-industrial continuous microwave oven (MWP) under different doses (low power/long time to high power/short time) or by conventional method (CP) were studied. All heat treatments reduced colour quality, total antioxidant capacity and vitamin C, with a greater reduction in CP than in MWP. On the other hand, use of an MWP, in particular high power/short time (1900 W/180 s, 2700 W/160 s and 3150 W/150 s) enhanced the viscosity and lycopene extraction and decreased the enzyme residual activity better than with CP samples. For tomato puree, polygalacturonase was the more thermo-resistant enzyme, and could be used as an indicator of pasteurization efficiency. MWP was an excellent pasteurization technique that provided tomato puree with improved nutritional quality, reducing process times compared to the standard pasteurization process. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Increasing the efficiency of the condensing boiler

NASA Astrophysics Data System (ADS)

Zaytsev, O. N.; Lapina, E. A.

2017-11-01

Analysis of existing designs of boilers with low power consumption showed that the low efficiency of the latter is due to the fact that they work in most cases when the heating period in the power range is significantly less than the nominal power. At the same time, condensing boilers do not work in the most optimal mode (in condensing mode) in the central part of Russia, a significant part of their total operating time during the heating season. This is due to existing methods of equipment selection and joint operation with heating systems with quantitative control of the coolant. It was also revealed that for the efficient operation of the heating system, it is necessary to reduce the inertia of the heat generating equipment. Theoretical patterns of thermal processes in the furnace during combustion gas at different radiating surfaces location schemes considering the influence of the very furnace configuration, characterized in that to reduce the work condensing boiler in conventional gas boiler operation is necessary to maintain a higher temperature in the furnace (in the part where spiral heat exchangers are disposed), which is possible when redistributing heat flow - increase the proportion of radiant heat from the secondary burner emitter allow Perey For the operation of the condensing boiler in the design (condensation) mode practically the entire heating period.

Spaceborne Processor Array

NASA Technical Reports Server (NTRS)

Chow, Edward T.; Schatzel, Donald V.; Whitaker, William D.; Sterling, Thomas

2008-01-01

A Spaceborne Processor Array in Multifunctional Structure (SPAMS) can lower the total mass of the electronic and structural overhead of spacecraft, resulting in reduced launch costs, while increasing the science return through dynamic onboard computing. SPAMS integrates the multifunctional structure (MFS) and the Gilgamesh Memory, Intelligence, and Network Device (MIND) multi-core in-memory computer architecture into a single-system super-architecture. This transforms every inch of a spacecraft into a sharable, interconnected, smart computing element to increase computing performance while simultaneously reducing mass. The MIND in-memory architecture provides a foundation for high-performance, low-power, and fault-tolerant computing. The MIND chip has an internal structure that includes memory, processing, and communication functionality. The Gilgamesh is a scalable system comprising multiple MIND chips interconnected to operate as a single, tightly coupled, parallel computer. The array of MIND components shares a global, virtual name space for program variables and tasks that are allocated at run time to the distributed physical memory and processing resources. Individual processor- memory nodes can be activated or powered down at run time to provide active power management and to configure around faults. A SPAMS system is comprised of a distributed Gilgamesh array built into MFS, interfaces into instrument and communication subsystems, a mass storage interface, and a radiation-hardened flight computer.

Energy-Efficient Data Collection Method for Sensor Networks by Integrating Asymmetric Communication and Wake-Up Radio

PubMed Central

Iwata, Masanari; Tang, Suhua; Obana, Sadao

2018-01-01

In large-scale wireless sensor networks (WSNs), nodes close to sink nodes consume energy more quickly than other nodes due to packet forwarding. A mobile sink is a good solution to this issue, although it causes two new problems to nodes: (i) overhead of updating routing information; and (ii) increased operating time due to aperiodic query. To solve these problems, this paper proposes an energy-efficient data collection method, Sink-based Centralized transmission Scheduling (SC-Sched), by integrating asymmetric communication and wake-up radio. Specifically, each node is equipped with a low-power wake-up receiver. The sink node determines transmission scheduling, and transmits a wake-up message using a large transmission power, directly activating a pair of nodes simultaneously which will communicate with a normal transmission power. This paper further investigates how to deal with frame loss caused by fading and how to mitigate the impact of the wake-up latency of communication modules. Simulation evaluations confirm that using multiple channels effectively reduces data collection time and SC-Sched works well with a mobile sink. Compared with the conventional duty-cycling method, SC-Sched greatly reduces total energy consumption and improves the network lifetime by 7.47 times in a WSN with 4 data collection points and 300 sensor nodes. PMID:29642397

Counterflow Regolith Heat Exchanger

NASA Technical Reports Server (NTRS)

Zubrin, Robert; Jonscher, Peter

2013-01-01

A problem exists in reducing the total heating power required to extract oxygen from lunar regolith. All such processes require heating a great deal of soil, and the heat energy is wasted if it cannot be recycled from processed material back into new material. The counterflow regolith heat exchanger (CoRHE) is a device that transfers heat from hot regolith to cold regolith. The CoRHE is essentially a tube-in-tube heat exchanger with internal and external augers attached to the inner rotating tube to move the regolith. Hot regolith in the outer tube is moved in one direction by a right-hand - ed auger, and the cool regolith in the inner tube is moved in the opposite direction by a left-handed auger attached to the inside of the rotating tube. In this counterflow arrangement, a large fraction of the heat from the expended regolith is transferred to the new regolith. The spent regolith leaves the heat exchanger close to the temperature of the cold new regolith, and the new regolith is pre-heated close to the initial temperature of the spent regolith. Using the CoRHE can reduce the heating requirement of a lunar ISRU system by 80%, reducing the total power consumption by a factor of two. The unique feature of this system is that it allows for counterflow heat exchange to occur between solids, instead of liquids or gases, as is commonly done. In addition, in variants of this concept, the hydrogen reduction can be made to occur within the counterflow heat exchanger itself, enabling a simplified lunar ISRU (in situ resource utilization) system with excellent energy economy and continuous nonbatch mode operation.

Operation of Direct Drive Systems: Experiments in Peak Power Tracking and Multi-Thruster Control

NASA Technical Reports Server (NTRS)

Snyder, John Steven; Brophy, John R.

2013-01-01

Direct-drive power and propulsion systems have the potential to significantly reduce the mass of high-power solar electric propulsion spacecraft, among other advantages. Recent experimental direct-drive work has significantly mitigated or retired the technical risks associated with single-thruster operation, so attention is now moving toward systems-level areas of interest. One of those areas is the use of a Hall thruster system as a peak power tracker to fully use the available power from a solar array. A simple and elegant control based on the incremental conductance method, enhanced by combining it with the unique properties of Hall thruster systems, is derived here and it is shown to track peak solar array power very well. Another area of interest is multi-thruster operation and control. Dualthruster operation was investigated in a parallel electrical configuration, with both thrusters operating from discharge power provided by a single solar array. Startup and shutdown sequences are discussed, and it is shown that multi-thruster operation and control is as simple as for a single thruster. Some system architectures require operation of multiple cathodes while they are electrically connected together. Four different methods to control the discharge current emitted by individual cathodes in this configuration are investigated, with cathode flow rate control appearing to be advantageous. Dual-parallel thruster operation with equal cathode current sharing at total powers up to 10 kW is presented.

A Multi-Resolution Mode CMOS Image Sensor with a Novel Two-Step Single-Slope ADC for Intelligent Surveillance Systems.

PubMed

Kim, Daehyeok; Song, Minkyu; Choe, Byeongseong; Kim, Soo Youn

2017-06-25

In this paper, we present a multi-resolution mode CMOS image sensor (CIS) for intelligent surveillance system (ISS) applications. A low column fixed-pattern noise (CFPN) comparator is proposed in 8-bit two-step single-slope analog-to-digital converter (TSSS ADC) for the CIS that supports normal, 1/2, 1/4, 1/8, 1/16, 1/32, and 1/64 mode of pixel resolution. We show that the scaled-resolution images enable CIS to reduce total power consumption while images hold steady without events. A prototype sensor of 176 × 144 pixels has been fabricated with a 0.18 μm 1-poly 4-metal CMOS process. The area of 4-shared 4T-active pixel sensor (APS) is 4.4 μm × 4.4 μm and the total chip size is 2.35 mm × 2.35 mm. The maximum power consumption is 10 mW (with full resolution) with supply voltages of 3.3 V (analog) and 1.8 V (digital) and 14 frame/s of frame rates.

Electrical load management at the Goldstone DSN Complex

NASA Technical Reports Server (NTRS)

Rayburn, J. C.

1981-01-01

A Power Load Management Plan was deveoped which utilizes the unique power generating capabilities of the stations to reduce the stress on the local utility's reserve capacity and reduce the cost of electrical power at the stations. The plan has greatly reduced the cost of Goldstone electrical power by completely eliminating the use of commercial power during the local utility's high usage periods each day.

Active Noise Control of Low Speed Fan Rotor-Stator Modes

NASA Technical Reports Server (NTRS)

Sutliff, Daniel L.; Hu, Ziqiang; Pla, Frederic G.; Heidelberg, Laurence J.

1996-01-01

This report describes the Active Noise Cancellation System designed by General Electric and tested in the NASA Lewis Research Center's 48 inch Active Noise Control Fan. The goal of this study was to assess the feasibility of using wall mounted secondary acoustic sources and sensors within the duct of a high bypass turbofan aircraft engine for active noise cancellation of fan tones. The control system is based on a modal control approach. A known acoustic mode propagating in the fan duct is cancelled using an array of flush-mounted compact sound sources. Controller inputs are signals from a shaft encoder and a microphone array which senses the residual acoustic mode in the duct. The canceling modal signal is generated by a modal controller. The key results are that the (6,0) mode was completely eliminated at 920 Hz and substantially reduced elsewhere. The total tone power was reduced 9.4 dB. Farfield 2BPF SPL reductions of 13 dB were obtained. The (4,0) and (4,1) modes were reduced simultaneously yielding a 15 dB modal PWL decrease. Global attenuation of PWL was obtained using an actuator and sensor system totally contained within the duct.

High accuracy switched-current circuits using an improved dynamic mirror

NASA Technical Reports Server (NTRS)

Zweigle, G.; Fiez, T.

1991-01-01

The switched-current technique, a recently developed circuit approach to analog signal processing, has emerged as an alternative/compliment to the well established switched-capacitor circuit technique. High speed switched-current circuits offer potential cost and power savings over slower switched-capacitor circuits. Accuracy improvements are a primary concern at this stage in the development of the switched-current technique. Use of the dynamic current mirror has produced circuits that are insensitive to transistor matching errors. The dynamic current mirror has been limited by other sources of error including clock-feedthrough and voltage transient errors. In this paper we present an improved switched-current building block using the dynamic current mirror. Utilizing current feedback the errors due to current imbalance in the dynamic current mirror are reduced. Simulations indicate that this feedback can reduce total harmonic distortion by as much as 9 dB. Additionally, we have developed a clock-feedthrough reduction scheme for which simulations reveal a potential 10 dB total harmonic distortion improvement. The clock-feedthrough reduction scheme also significantly reduces offset errors and allows for cancellation with a constant current source. Experimental results confirm the simulated improvements.

Antioxidant capacity and fatty acid composition of different parts of Adenocarpus complicatus (Fabaceae) from Turkey.

PubMed

Berber, Adnan; Zengin, Gokhan; Aktumsek, Abdurrahman; Sanda, Murad Aydin; Uysal, Tuna

2014-03-01

Adenocarpus complicatus is distributed throughout the Anatolian peninsula and is widely used for human and animal nutrition. The purpose of this work was to study the antioxidant properties and fatty acid composition of different parts of this plant (fruits and mixed materials). The species was collected from Golyuzu village of the Seydisehir district near Konya province, Turkey. Fruit and mixed parts obtained from this species were ground and a 15g sample was used to prepare methanolic extracts. Powdered plant samples were extracted with 100mL methanol in a mechanical shaker. The obtained extracts were filtered and concentrated to dryness under reduced pressure and were subsequently stored at -20 degrees C. Antioxidant components, namely total phenolic and flavonoid content, were detected for each extract using spectrophotometric methods. Antioxidant capacity was evaluated by various assays including phosphomolybdenum, DPPH free radical scavenging capacity, metal chelating activity, and ferric and cupric ion reducing power. The fatty acid profiles of plant parts were also determined by using gas chromatography. The total phenolic content of fruit (36.21mgGAE/g) was higher than that of mixed materials (13.79mgGAE/g). The methanolic extract of mixed material had higher amounts of flavonoid than fruit extract. The free radical scavenging activity of extracts was expressed as IC50 value (microg/mL) (amount required to inhibit DPPH radical formation by 50%). The lower IC50 value reflects better free radical scavenging action. The radical scavenging activity of the samples was compared with BHT, it showed the mixed material to be almost two times more potent than the fruit extract. However, BHT is an excellent free radical scavenger with an IC50 of 34.061 microg/mL. The ferric and cupric reducing power potentials of the extracts were expressed as EC50 value (the effective concentration at which the absorbance was 0.5). Fruit extract exhibited strong ferric reducing power with an EC50 of 871.25 microg/mL. The metal chelating activity of the extracts increased with concentration. Chelating effect was 83.60% for fruit extract at 1mg/mL concentration. Oil content of fruit and mixed parts were detected as 6.71 and 6.14%, respectively. A total of 32 fatty acids were found in the oil. Essential fatty acids (linoleic and a-linolenic acid) were identified as the most abundant fatty acids in the oil. These results demonstrated that this plant species can be considered as an alternative to synthetic antioxidants. Likewise, the oil obtained from the plant can be used as a source of essential fatty acids for food and pharmacological applications.

Power allocation strategies to minimize energy consumption in wireless body area networks.

PubMed

Kailas, Aravind

2011-01-01

The wide scale deployment of wireless body area networks (WBANs) hinges on designing energy efficient communication protocols to support the reliable communication as well as to prolong the network lifetime. Cooperative communications, a relatively new idea in wireless communications, offers the benefits of multi-antenna systems, thereby improving the link reliability and boosting energy efficiency. In this short paper, the advantages of resorting to cooperative communications for WBANs in terms of minimized energy consumption are investigated. Adopting an energy model that encompasses energy consumptions in the transmitter and receiver circuits, and transmitting energy per bit, it is seen that cooperative transmission can improve energy efficiency of the wireless network. In particular, the problem of optimal power allocation is studied with the constraint of targeted outage probability. Two strategies of power allocation are considered: power allocation with and without posture state information. Using analysis and simulation-based results, two key points are demonstrated: (i) allocating power to the on-body sensors making use of the posture information can reduce the total energy consumption of the WBAN; and (ii) when the channel condition is good, it is better to recruit less relays for cooperation to enhance energy efficiency.

Taking SiC Power Devices to the Final Frontier: Addressing Challenges of the Space Radiation Environment

NASA Technical Reports Server (NTRS)

Lauenstein, Jean-Marie; Casey, Megan

2017-01-01

Silicon carbide power device technology has the potential to enable a new generation of aerospace power systems that demand high efficiency, rapid switching, and reduced mass and volume in order to expand space-based capabilities. For this potential to be realized, SiC devices must be capable of withstanding the harsh space radiation environment. Commercial SiC components exhibit high tolerance to total ionizing dose but to date, have not performed well under exposure to heavy ion radiation representative of the on-orbit galactic cosmic rays. Insertion of SiC power device technology into space applications to achieve breakthrough performance gains will require intentional development of components hardened to the effects of these highly-energetic heavy ions. This work presents heavy-ion test data obtained by the authors over the past several years for discrete SiC power MOSFETs, JFETs, and diodes in order to increase the body of knowledge and understanding that will facilitate hardening of this technology to space radiation effects. Specifically, heavy-ion irradiation data taken under different bias, temperature, and ion beam conditions is presented for devices from different manufacturers, and the emerging patterns discussed.

Validation of the Predicted Circumferential and Radial Mode Sound Power Levels in the Inlet and Exhaust Ducts of a Fan Ingesting Distorted Inflow

NASA Technical Reports Server (NTRS)

Koch, L. Danielle

2012-01-01

Fan inflow distortion tone noise has been studied computationally and experimentally. Data from two experiments in the NASA Glenn Advanced Noise Control Fan rig have been used to validate acoustic predictions. The inflow to the fan was distorted by cylindrical rods inserted radially into the inlet duct one rotor chord length upstream of the fan. The rods were arranged in both symmetric and asymmetric circumferential patterns. In-duct and farfield sound pressure level measurements were recorded. It was discovered that for positive circumferential modes, measured circumferential mode sound power levels in the exhaust duct were greater than those in the inlet duct and for negative circumferential modes, measured total circumferential mode sound power levels in the exhaust were less than those in the inlet. Predicted trends in overall sound power level were proven to be useful in identifying circumferentially asymmetric distortion patterns that reduce overall inlet distortion tone noise, as compared to symmetric arrangements of rods. Detailed comparisons between the measured and predicted radial mode sound power in the inlet and exhaust duct indicate limitations of the theory.

Fused-fiber-based 3-dB mode insensitive power splitters for few-mode optical fiber networks

NASA Astrophysics Data System (ADS)

Ren, Fang; Huang, Xiaoshan; Wang, Jianping

2017-11-01

We propose a 3-dB mode insensitive power splitter (MIPS) capable of broadcasting and combining optical signals. It is fabricated with two identical few-mode fibers (FMFs) by a heating and pulling technique. The mode-dependent power transfer characteristic as a function of pulling length is investigated. For exploiting its application, we experimentally demonstrate both FMF-based transmissive and reflective star couplers consisting of multiple 3-dB mode insensitive power splitters, which perform broadcasting and routing signals in few-mode optical fiber networks such as mode-division multiplexing (MDM) local area networks using star topology. For experimental demonstration, optical on-off keying signals at 10 Gb/s carried on three spatial modes are successfully processed with open and clear eye diagrams. Measured bit error ratio results show reasonable power penalties. It is found that a reflective star coupler in MDM networks can reduce half of the total amount of required fibers comparing to that of a transmissive star coupler. This MIPS is more efficient, more reliable, more flexible, and more cost-effective for future expansion and application in few-mode optical fiber networks.

Design of a Telescopic Linear Actuator Based on Hollow Shape Memory Springs

NASA Astrophysics Data System (ADS)

Spaggiari, Andrea; Spinella, Igor; Dragoni, Eugenio

2011-07-01

Shape memory alloys (SMAs) are smart materials exploited in many applications to build actuators with high power to mass ratio. Typical SMA drawbacks are: wires show poor stroke and excessive length, helical springs have limited mechanical bandwidth and high power consumption. This study is focused on the design of a large-scale linear SMA actuator conceived to maximize the stroke while limiting the overall size and the electric consumption. This result is achieved by adopting for the actuator a telescopic multi-stage architecture and using SMA helical springs with hollow cross section to power the stages. The hollow geometry leads to reduced axial size and mass of the actuator and to enhanced working frequency while the telescopic design confers to the actuator an indexable motion, with a number of different displacements being achieved through simple on-off control strategies. An analytical thermo-electro-mechanical model is developed to optimize the device. Output stroke and force are maximized while total size and power consumption are simultaneously minimized. Finally, the optimized actuator, showing good performance from all these points of view, is designed in detail.

Design analysis of levitation facility for space processing applications. [Skylab program, space shuttles

NASA Technical Reports Server (NTRS)

Frost, R. T.; Kornrumpf, W. P.; Napaluch, L. J.; Harden, J. D., Jr.; Walden, J. P.; Stockhoff, E. H.; Wouch, G.; Walker, L. H.

1974-01-01

Containerless processing facilities for the space laboratory and space shuttle are defined. Materials process examples representative of the most severe requirements for the facility in terms of electrical power, radio frequency equipment, and the use of an auxiliary electron beam heater were used to discuss matters having the greatest effect upon the space shuttle pallet payload interfaces and envelopes. Improved weight, volume, and efficiency estimates for the RF generating equipment were derived. Results are particularly significant because of the reduced requirements for heat rejection from electrical equipment, one of the principal envelope problems for shuttle pallet payloads. It is shown that although experiments on containerless melting of high temperature refractory materials make it desirable to consider the highest peak powers which can be made available on the pallet, total energy requirements are kept relatively low by the very fast processing times typical of containerless experiments and allows consideration of heat rejection capabilities lower than peak power demand if energy storage in system heat capacitances is considered. Batteries are considered to avoid a requirement for fuel cells capable of furnishing this brief peak power demand.

An ultra-low power self-timed column-level ADC for a CMOS pixel sensor based vertex detector

NASA Astrophysics Data System (ADS)

Zhang, L.; Wang, M.

2014-11-01

The International Large Detector (ILD) is a detector concept for the future linear collider experiment. The vertex detector is the key tool to achieve high precision measurements for flavor tagging, which puts stringent requirements on the CMOS pixel sensors. Due to the cooling systems which deteriorate the material budget and increase the multiple scattering, it is important to reduce the power consumption. This paper presents an ultra-low power self-timed column-level ADC for the CMOS pixel sensors, aiming to equip the outer layers of the vertex detector. The ADC was designed to operate in two modes (active and idle) adapted to the low hit density in the outer layers. The architecture employs an enhanced sample-and-hold circuit and a self-timed technique. The total power consumption with a 3-V supply is 225μW during idle mode, which is the most frequent situation. This value rises to 425μW in the case of the active mode. It occupies an area of 35 × 590μm2.

Effect of lensing non-Gaussianity on the CMB power spectra

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

Lewis, Antony; Pratten, Geraint, E-mail: antony@cosmologist.info, E-mail: geraint.pratten@gmail.com

2016-12-01

Observed CMB anisotropies are lensed, and the lensed power spectra can be calculated accurately assuming the lensing deflections are Gaussian. However, the lensing deflections are actually slightly non-Gaussian due to both non-linear large-scale structure growth and post-Born corrections. We calculate the leading correction to the lensed CMB power spectra from the non-Gaussianity, which is determined by the lensing bispectrum. Assuming no primordial non-Gaussianity, the lowest-order result gives ∼ 0.3% corrections to the BB and EE polarization spectra on small-scales. However we show that the effect on EE is reduced by about a factor of two by higher-order Gaussian lensing smoothing,more » rendering the total effect safely negligible for the foreseeable future. We give a simple analytic model for the signal expected from skewness of the large-scale lensing field; the effect is similar to a net demagnification and hence a small change in acoustic scale (and therefore out of phase with the dominant lensing smoothing that predominantly affects the peaks and troughs of the power spectrum).« less

A Low Power SOC Architecture for the V2.0+EDR Bluetooth Using a Unified Verification Platform

NASA Astrophysics Data System (ADS)

Kim, Jeonghun; Kim, Suki; Baek, Kwang-Hyun

This paper presents a low-power System on Chip (SOC) architecture for the v2.0+EDR (Enhanced Data Rate) Bluetooth and its applications. Our design includes a link controller, modem, RF transceiver, Sub-Band Codec (SBC), Expanded Instruction Set Computer (ESIC) processor, and peripherals. To decrease power consumption of the proposed SOC, we reduce data transfer using a dual-port memory, including a power management unit, and a clock gated approach. We also address some of issues and benefits of reusable and unified environment on a centralized data structure and SOC verification platform. This includes flexibility in meeting the final requirements using technology-independent tools wherever possible in various processes and for projects. The other aims of this work are to minimize design efforts by avoiding the same work done twice by different people and to reuse the similar environment and platform for different projects. This chip occupies a die size of 30mm2 in 0.18µm CMOS, and the worst-case current of the total chip is 54mA.

A High Performance Delta-Sigma Modulator for Neurosensing

PubMed Central

Xu, Jian; Zhao, Menglian; Wu, Xiaobo; Islam, Md. Kafiul; Yang, Zhi

2015-01-01

Recorded neural data are frequently corrupted by large amplitude artifacts that are triggered by a variety of sources, such as subject movements, organ motions, electromagnetic interferences and discharges at the electrode surface. To prevent the system from saturating and the electronics from malfunctioning due to these large artifacts, a wide dynamic range for data acquisition is demanded, which is quite challenging to achieve and would require excessive circuit area and power for implementation. In this paper, we present a high performance Delta-Sigma modulator along with several design techniques and enabling blocks to reduce circuit area and power. The modulator was fabricated in a 0.18-μm CMOS process. Powered by a 1.0-V supply, the chip can achieve an 85-dB peak signal-to-noise-and-distortion ratio (SNDR) and an 87-dB dynamic range when integrated over a 10-kHz bandwidth. The total power consumption of the modulator is 13 μW, which corresponds to a figure-of-merit (FOM) of 45 fJ/conversion step. These competitive circuit specifications make this design a good candidate for building high precision neurosensors. PMID:26262623

Active Vibration Reduction of the Advanced Stirling Convertor

NASA Technical Reports Server (NTRS)

Wilson, Scott D.; Metscher, Jonathan F.; Schifer, Nicholas A.

2016-01-01

Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint compared to the current state of the art. The Stirling Cycle Technology Development (SCTD) Project is funded by the RPS Program to developing Stirling-based subsystems, including convertors and controller maturation efforts that have resulted in high fidelity hardware like the Advanced Stirling Radioisotope Generator (ASRG), Advanced Stirling Convertor (ASC), and ASC Controller Unit (ACU). The SCTD Project also performs research to develop less mature technologies with a wide variety of objectives, including increasing temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Active vibration reduction systems (AVRS), or "balancers", have historically been developed and characterized to provide fault tolerance for generator designs that incorporate dual-opposed Stirling convertors or enable single convertor, or small RPS, missions. Balancers reduce the dynamic disturbance forces created by the power piston and displacer internal moving components of a single operating convertor to meet spacecraft requirements for induced disturbance force. To improve fault tolerance for dual-opposed configurations and enable single convertor configurations, a breadboard AVRS was implemented on the Advanced Stirling Convertor (ASC). The AVRS included a linear motor, a motor mount, and a closed-loop controller able to balance out the transmitted peak dynamic disturbance using acceleration feedback. Test objectives included quantifying power and mass penalty and reduction in transmitted force over a range of ASC operating parameters and mounting conditions. All tests were performed at three different piston amplitudes, 3.0 mm, 3.75 mm, and 4.5 mm. Overall, the transmitted force was reduced to 2% of the total unbalanced force by actively balancing out only the first fundamental frequency, with balancer motor power remaining under one watt. The test results will be used to guide future balancer designs.

Competing Air Quality and Water Conservation Co-benefits from Power Sector Decarbonization

NASA Astrophysics Data System (ADS)

Peng, W.; Wagner, F.; Mauzerall, D. L.; Ramana, M. V.; Zhai, H.; Small, M.; Zhang, X.; Dalin, C.

2016-12-01

Decarbonizing the power sector can reduce fossil-based generation and associated air pollution and water use. However, power sector configurations that prioritize air quality benefits can be different from those that maximize water conservation benefits. Despite extensive work to optimize the generation mix under an air pollution or water constraint, little research has examined electricity transmission networks and the choice of which fossil fuel units to displace in order to achieve both environmental objectives simultaneously. When air pollution and water stress occur in different regions, the optimal transmission and displacement decisions still depend on priorities placed on air quality and water conservation benefits even if low-carbon generation planning is fixed. Here we use China as a test case, and develop a new optimization framework to study transmission and displacement decisions and the resulting air quality and water use impacts for six power sector decarbonization scenarios in 2030 ( 50% of national generation is low carbon). We fix low-carbon generation in each scenario (e.g. type, location, quantity) and vary technology choices and deployment patterns across scenarios. The objective is to minimize the total physical costs (transmission costs and coal power generation costs) and the estimated environmental costs. Environmental costs are estimated by multiplying effective air pollutant emissions (EMeff, emissions weighted by population density) and effective water use (Weff, water use weighted by a local water stress index) by their unit economic values, Vem and Vw. We are hence able to examine the effect of varying policy priorities by imposing different combinations of Vem and Vw. In all six scenarios, we find that increasing the priority on air quality co-benefits (higher Vem) reduces air pollution impacts (lower EMeff) at the expense of lower water conservation (higher Weff); and vice versa. Such results can largely be explained by differences in optimal transmission decisions due to different locations of air pollution and water stress in China (severe in the east and north respectively). To achieve both co-benefits simultaneously, it is therefore critical to coordinate policies that reduce air pollution (pollution tax) and water use (water pricing) with power sector planning.

Active Vibration Reduction of the Advanced Stirling Convertor

NASA Technical Reports Server (NTRS)

Wilson, Scott D.; Metscher, Jonathan F.; Schifer, Nicholas A.

2016-01-01

Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint compared to the current state of the art. The Stirling Cycle Technology Development (SCTD) Project is funded by the RPS Program to developing Stirling-based subsystems, including convertors and controller maturation efforts that have resulted in high fidelity hardware like the Advanced Stirling Radioisotope Generator (ASRG), Advanced Stirling Convertor (ASC), and ASC Controller Unit (ACU). The SCTD Project also performs research to develop less mature technologies with a wide variety of objectives, including increasing temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Active vibration reduction systems (AVRS), or "balancers", have historically been developed and characterized to provide fault tolerance for generator designs that incorporate dual-opposed Stirling convertors or enable single convertor, or small RPS, missions. Balancers reduce the dynamic disturbance forces created by the power piston and displacer internal moving components of a single operating convertor to meet spacecraft requirements for induced disturbance force. To improve fault tolerance for dual-opposed configurations and enable single convertor configurations, a breadboard AVRS was implemented on the Advanced Stirling Convertor (ASC). The AVRS included a linear motor, a motor mount, and a closed-loop controller able to balance out the transmitted peak dynamic disturbance using acceleration feedback. Test objectives included quantifying power and mass penalty and reduction in transmitted force over a range of ASC operating parameters and mounting conditions. All tests were performed at three different piston amplitudes, 3.0, 3.75, and 4.5 mm. Overall, the transmitted force was reduced to 2 percent of the total unbalanced force by actively balancing out only the first fundamental frequency, with balancer motor power remaining under 1 watt. The test results will be used to guide future balancer designs.

Robotic surgery for lung resections—total port approach: advantages and disadvantages

PubMed Central

Ramadan, Omar I.; Cerfolio, Robert J.

2017-01-01

Minimally invasive thoracic surgery, when compared with open thoracotomy, has been shown to have improved perioperative outcomes as well as comparable long-term survival. Robotic surgery represents a powerful advancement of minimally invasive surgery, with vastly improved visualization and instrument maneuverability, and is increasingly popular for thoracic surgery. However, there remains debate over the best robotic approaches for lung resection, with several different techniques evidenced and described in the literature. We delineate our method for total port approach with four robotic arms and discuss how its advantages outweigh its disadvantages. We conclude that it is preferred to other robotic approaches, such as the robotic assisted approach, due to its enhanced visualization, improved instrument range of motion, and reduced potential for injury. PMID:29078585

Robotic surgery for lung resections-total port approach: advantages and disadvantages.

PubMed

Ramadan, Omar I; Wei, Benjamin; Cerfolio, Robert J

2017-01-01

Minimally invasive thoracic surgery, when compared with open thoracotomy, has been shown to have improved perioperative outcomes as well as comparable long-term survival. Robotic surgery represents a powerful advancement of minimally invasive surgery, with vastly improved visualization and instrument maneuverability, and is increasingly popular for thoracic surgery. However, there remains debate over the best robotic approaches for lung resection, with several different techniques evidenced and described in the literature. We delineate our method for total port approach with four robotic arms and discuss how its advantages outweigh its disadvantages. We conclude that it is preferred to other robotic approaches, such as the robotic assisted approach, due to its enhanced visualization, improved instrument range of motion, and reduced potential for injury.

Separation of curcuminoids enriched fraction from spent turmeric oleoresin and its antioxidant potential.

PubMed

Nagarajan, S; Kubra, I Rahath; Rao, L Jagan Mohan

2010-08-01

The rhizomes of turmeric are processed to obtain oleoresin and subsequently curcuminoids are isolated. The mother liquor, after partial isolation of curcuminoids, known as spent turmeric oleoresin (STO), is considered as industrial waste. Curcuminoids enriched spent turmeric oleoresin (CSTO) is prepared by removal of nonantioxidant constituents, and investigated for its antioxidant potential using in vitro methods, and also the total curcuminoids and phenolic contents were determined. CSTO has a total phenolic content of 267.27 +/- 5.75 mg GAE/g that is almost double the amount present in STO (118.3 +/- 3.0 mg GAE/g). The total amount of curcuminoids in CSTO is found to be 39 +/- 1.2%, whereas STO had 15 +/- 2.0%. CSTO possessed radical scavenging activity of 84% at 50 microg/mL, antioxidant activity of 74% at 25 microg/mL, high antioxidant capacity, and moderate total reducing power. These results provide scope for utilization of CSTO/STO as natural antioxidant/preservative as well as colorant in various foods.

Effect of different cooking methods on total phenolic contents and antioxidant activities of four Boletus mushrooms.

PubMed

Sun, Liping; Bai, Xue; Zhuang, Yongliang

2014-11-01

The influences of cooking methods (steaming, pressure-cooking, microwaving, frying and boiling) on total phenolic contents and antioxidant activities of fruit body of Boletus mushrooms (B. aereus, B. badius, B. pinophilus and B. edulis) have been evaluated. The results showed that microwaving was better in retention of total phenolics than other cooking methods, while boiling significantly decreased the contents of total phenolics in samples under study. Effects of different cooking methods on phenolic acids profiles of Boletus mushrooms showed varieties with both the species of mushroom and the cooking method. Effects of cooking treatments on antioxidant activities of Boletus mushrooms were evaluated by in vitro assays of hydroxyl radical (OH·) -scavenging activity, reducing power and 1, 1-diphenyl-2-picrylhydrazyl radicals (DPPH·) -scavenging activity. Results indicated the changes of antioxidant activities of four Boletus mushrooms were different in five cooking methods. This study could provide some information to encourage food industry to recommend particular cooking methods.

Influence of Cooking Methods on Bioactive Compound Content and Antioxidant Activity of Brussels Sprouts.

PubMed

Hwang, Eun-Sun

2017-12-01

The effects of different cooking methods on total bioactive compound content were determined, and in vitro antioxidant activity in 80% ethanolic extracts of Brussels sprouts was evaluated by spectrophotometric methods. Compared to uncooked, steamed, and microwaved Brussels sprouts extracted with 80% ethanol contained higher amounts of total polyphenols. Uncooked Brussels sprouts contained the highest amounts of total flavonoids. Microwaved Brussels sprouts contained the highest amounts of total carotenoids (0.35 mg/g) and chlorophylls (3.01 mg/g), followed by steamed and uncooked samples. Uncooked fresh Brussels sprouts showed the highest antioxidant activity followed by microwaved and steamed sprouts. Antioxidant activity was measured with the 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and hydroxyl racial scavenging assays as well as the reducing power activity assay, and antioxidant activity was found to increase in a concentration-dependent manner. Based on these results, cooking or heat treatment may decrease antioxidant activities, although their effect on bioactive compound content remains controversial.

Space Station Freedom - Configuration management approach to supporting concurrent engineering and total quality management. [for NASA Space Station Freedom Program

NASA Technical Reports Server (NTRS)

Gavert, Raymond B.

1990-01-01

Some experiences of NASA configuration management in providing concurrent engineering support to the Space Station Freedom program for the achievement of life cycle benefits and total quality are discussed. Three change decision experiences involving tracing requirements and automated information systems of the electrical power system are described. The potential benefits of concurrent engineering and total quality management include improved operational effectiveness, reduced logistics and support requirements, prevention of schedule slippages, and life cycle cost savings. It is shown how configuration management can influence the benefits attained through disciplined approaches and innovations that compel consideration of all the technical elements of engineering and quality factors that apply to the program development, transition to operations and in operations. Configuration management experiences involving the Space Station program's tiered management structure, the work package contractors, international partners, and the participating NASA centers are discussed.

Evaluation of antioxidant potential of Lavandula x intermedia Emeric ex Loisel. 'Budrovka': a comparative study with L. angustifolia Mill.

PubMed

Blazeković, Biljana; Vladimir-Knezević, Sanda; Brantner, Adelheid; Stefan, Maja Bival

2010-08-30

A Croatian indigenous cultivar of lavandin, Lavandula x intermedia 'Budrovka' (Lamiaceae) was studied for the phenolic acids, flavonoids, anthocyanins, procyanidins and total tannins, as well as total polyphenols content, in the flower, inflorescence stalk and leaf ethanolic extracts. Antioxidant potentials on these plant part extracts were assessed by the DPPH free radical scavenging activity, iron chelating activity, reducing power, lipid peroxidation inhibition properties and total antioxidant capacity assays. All results were compared with those of Lavandula angustifolia, the only member of the Lavandula genus officially used in modern phytotherapy. Based on the results of our parallel study, we may suggest that Lavandula x intermedia 'Budrovka' is as potent an antioxidant as Lavandula angustifolia and the antioxidant activity of the Lavandula extracts is mainly due to the presence of rosmarinic acid. A good correlation was found between the polyphenol contents and antioxidant activities of the extracts.

Antioxidant Content, Antioxidant Activity, and Antibacterial Activity of Five Plants from the Commelinaceae Family

PubMed Central

Tan, Joash Ban Lee; Yap, Wei Jin; Tan, Shen Yeng; Lim, Yau Yan; Lee, Sui Mae

2014-01-01

Commelinaceae is a family of herbaceous flowering plants with many species used in ethnobotany, particularly in South America. However, thus far reports of their bioactivity are few and far between. The primary aim of this study was to quantify the antioxidant and antibacterial activity of five Commelinaceae methanolic leaf extracts. The antioxidant content was evaluated by the total phenolic content (TPC), total tannin content (TTC), and total flavonoid content (TFC) assays. The antioxidant activities measured were DPPH free radical scavenging (FRS), ferric reducing power (FRP), and ferrous ion chelating (FIC); of the five plants, the methanolic leaf extract of Tradescantia zebrina showed the highest antioxidant content and activity, and exhibited antibacterial activity against six species of Gram-positive and two species of Gram-negative bacteria in a range of 5–10 mg/mL based on the broth microdilution method. PMID:26785239

The COMMAND trial of cognitive therapy to prevent harmful compliance with command hallucinations: predictors of outcome and mediators of change.

PubMed

Birchwood, Max; Dunn, Graham; Meaden, Alan; Tarrier, Nicholas; Lewis, Shon; Wykes, Til; Davies, Linda; Michail, Maria; Peters, Emmanuelle

2017-12-05

Acting on harmful command hallucinations is a major clinical concern. Our COMMAND CBT trial approximately halved the rate of harmful compliance (OR = 0.45, 95% CI 0.23-0.88, p = 0.021). The focus of the therapy was a single mechanism, the power dimension of voice appraisal, was also significantly reduced. We hypothesised that voice power differential (between voice and voice hearer) was the mediator of the treatment effect. The trial sample (n = 197) was used. A logistic regression model predicting 18-month compliance was used to identify predictors, and an exploratory principal component analysis (PCA) of baseline variables used as potential predictors (confounders) in their own right. Stata's paramed command used to obtain estimates of the direct, indirect and total effects of treatment. Voice omnipotence was the best predictor although the PCA identified a highly predictive cognitive-affective dimension comprising: voices' power, childhood trauma, depression and self-harm. In the mediation analysis, the indirect effect of treatment was fully explained by its effect on the hypothesised mediator: voice power differential. Voice power and treatment allocation were the best predictors of harmful compliance up to 18 months; post-treatment, voice power differential measured at nine months was the mediator of the effect of treatment on compliance at 18 months.

Power consumption of rotary blood pumps: pulsatile versus constant-speed mode.

PubMed

Pirbodaghi, Tohid; Cotter, Chris; Bourque, Kevin

2014-12-01

We investigated the power consumption of a HeartMate III rotary blood pump based on in vitro experiments performed in a cardiovascular simulator. To create artificial-pulse mode, we modulated the pump speed by decreasing the mean speed by 2000 rpm for 200 ms and then increasing speed by 4000 rpm (mean speeds plus 2000 rpm) for another 200 ms, creating a square waveform shape. The HeartMate III was connected to a cardiovascular simulator consisting of a hydraulic pump system to simulate left ventricle pumping action, arterial and venous compliance chambers, and an adjustable valve for peripheral resistance to facilitate the desired aortic pressure. The simulator operated based on Suga's elastance model to mimic the Starling response of the heart, thereby reproducing physiological blood flow and pressure conditions. We measured the instantaneous total electrical current and voltage of the pump to evaluate its power consumption. The aim was to answer these fundamental questions: (i) How does pump speed modulation affect pump power consumption? (ii) How does the power consumption vary in relation to external pulsatile flow? The results indicate that speed modulation and external pulsatile flow both moderately increase the power consumption. Increasing the pump speed reduces the impact of external pulsatile flow. Copyright © 2014 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

Chemical Composition and Bioactivities of Two Common Chaenomeles Fruits in China: Chaenomeles speciosa and Chaenomeles sinensis.

PubMed

Miao, Jing; Zhao, Chengcheng; Li, Xia; Chen, Xuetao; Mao, Xinhui; Huang, Hanhan; Wang, Tingting; Gao, Wenyuan

2016-08-01

Contents of total flavonoids, total phenolics, total triterpenes, total condensed tannin and total saponins in peels, flesh and endocarps of Chaenomeles speciosa (CSP) and Chaenomeles sinensis (CSS) were determined by colorimetric method, while 5 phenolics (vanillic, gallic, chlorogenic, ferulic and p-coumaric acids), 2 triterpenes (oleanolic and ursolic acids), and 3 flavonoids (rutin, catechin and epicatechin) were identified and quantified by high-performance liquid chromatography-mass spectrometry (HPLC-MS) and HPLC, and antioxidant and α-glucosidase inhibitory activities of them also were evaluated as well as their digestive characteristics. In the correlation analysis, total phenolics, vanillic acid, catechin, ursolic acid and oleanolic acid all contribute to DPPH(·) scavenge capacity, gallic acid contributes to total ferric reducing antioxidant power, while total triterpenes, total saponins, chlorogenic acid and ferullic acid contribute to α-glucosidase inhibitory activity. In the principal component analysis, endocarps of CSP and CSS both show better quality than their peels and flesh, respectively. In vitro digestion can increase contents of total flavonoids, total condensed tannin and total saponins, while contents of total phenolics and total triterpenes decreased greatly. Our study would contribute to the full use of discarded parts of the 2 Chaenomeles and be helpful to establish a good foundation for further research of CSP and CSS. © 2016 Institute of Food Technologists®

A standard for test reliability in group research.

PubMed

Ellis, Jules L

2013-03-01

Many authors adhere to the rule that test reliabilities should be at least .70 or .80 in group research. This article introduces a new standard according to which reliabilities can be evaluated. This standard is based on the costs or time of the experiment and of administering the test. For example, if test administration costs are 7 % of the total experimental costs, the efficient value of the reliability is .93. If the actual reliability of a test is equal to this efficient reliability, the test size maximizes the statistical power of the experiment, given the costs. As a standard in experimental research, it is proposed that the reliability of the dependent variable be close to the efficient reliability. Adhering to this standard will enhance the statistical power and reduce the costs of experiments.

Rf system for the NSLS coherent infrared radiation source

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

Broome, W.; Biscardi, R.; Keane, J.

1995-05-01

The existing NSLS X-ray Lithography Source (XLS Phase I) is being considered for a coherent synchrotron radiation source. The existing 211 MHz warm cavity will be replaced with a 5-cell 2856 MHz superconducting RF cavity, driven by a series of 2 kW klystrons. The RF system will provide a total V{sub RF} of 1.5 MV to produce {sigma}{sub L} = 0.3 mm electron bunches at an energy of 150 MeV. Superconducting technology significantly reduces the required space and power needed to achieve the higher voltage. It is the purpose of this paper to describe the superconducting RF system and cavity,more » power requirements, and cavity design parameters such as input coupling, Quality Factor, and Higher Order Modes.« less

An important factor powerfully influencing the Al Ni-based alloys' glass-forming ability

NASA Astrophysics Data System (ADS)

Bo, Zhang; Xiufang, Bian; Chunxia, Fu; Na, Han; Jiankun, Zhou; Weimin, Wang

2005-12-01

In order to get better glass-forming abilities (GFAs), Ni atoms are partially replaced by Cu and Co atoms in Al84Ni12Zr4 alloys. Thermal analysis shows that the reduced crystallization temperature Trx has no direct correlation with the GFA of the alloys. However, it is notable that prepeaks have been found in the total structure factors of the amorphous Al84Ni(12-x)Zr4Cux and Al84Ni(12-x)Zr4Cox alloys. In addition, the results prove that the intensity of the prepeaks influences the GFA powerfully. The amorphous alloys with larger intensity of the prepeak show better GFA. The influence of prepeaks on the GFA can be explained by the atomic configuration difference among the liquid, crystal and glass states.

Current status of radiological protection at nuclear power stations in Japan.

PubMed

Suzuki, Akira; Hori, Shunsuke

2011-07-01

The radiation dose to workers at nuclear power stations (NPSs) in Japan was drastically reduced between the late-1970s and the early-1990s by continuous dose-reduction programmes. The total collective dose of radiation workers in FY 2008 was 84.04 person Sv, while the average collective dose was 1.5 person Sv per reactor. The average annual individual dose was 1.1 mSv and the maximum annual individual dose was 19.5 mSv. These values are sufficiently lower than the regulatory dose limits. Radioactive effluent released from NPSs is already so trivial that additional protective measures will not be necessary. Experience in radiation protection at NPSs has been accumulated over 40 y and will be very useful in establishing a rational radiation control system in the future.

Biomass energy: Sustainable solution for greenhouse gas emission

NASA Astrophysics Data System (ADS)

Sadrul Islam, A. K. M.; Ahiduzzaman, M.

2012-06-01

Biomass is part of the carbon cycle. Carbon dioxide is produced after combustion of biomass. Over a relatively short timescale, carbon dioxide is renewed from atmosphere during next generation of new growth of green vegetation. Contribution of renewable energy including hydropower, solar, biomass and biofuel in total primary energy consumption in world is about 19%. Traditional biomass alone contributes about 13% of total primary energy consumption in the world. The number of traditional biomass energy users expected to rise from 2.5 billion in 2004 to 2.6 billion in 2015 and to 2.7 billion in 2030 for cooking in developing countries. Residential biomass demand in developing countries is projected to rise from 771 Mtoe in 2004 to 818 Mtoe in 2030. The main sources of biomass are wood residues, bagasse, rice husk, agro-residues, animal manure, municipal and industrial waste etc. Dedicated energy crops such as short-rotation coppice, grasses, sugar crops, starch crops and oil crops are gaining importance and market share as source of biomass energy. Global trade in biomass feedstocks and processed bioenergy carriers are growing rapidly. There are some drawbacks of biomass energy utilization compared to fossil fuels viz: heterogeneous and uneven composition, lower calorific value and quality deterioration due to uncontrolled biodegradation. Loose biomass also is not viable for transportation. Pelletization, briquetting, liquefaction and gasification of biomass energy are some options to solve these problems. Wood fuel production is very much steady and little bit increase in trend, however, the forest land is decreasing, means the deforestation is progressive. There is a big challenge for sustainability of biomass resource and environment. Biomass energy can be used to reduce greenhouse emissions. Woody biomass such as briquette and pellet from un-organized biomass waste and residues could be used for alternative to wood fuel, as a result, forest will be saved and sustainable carbon sink will be developed. Clean energy production from biomass (such as ethanol, biodiesel, producer gas, bio-methane) could be viable option to reduce fossil fuel consumption. Electricity generation from biomass is increasing throughout the world. Co-firing of biomass with coal and biomass combustion in power plant and CHP would be a viable option for clean energy development. Biomass can produce less emission in the range of 14% to 90% compared to emission from fossil for electricity generation. Therefore, biomass could play a vital role for generation of clean energy by reducing fossil energy to reduce greenhouse gas emissions. The main barriers to expansion of power generation from biomass are cost, low conversion efficiency and availability of feedstock. Internationalization of external cost in power generation and effective policies to improve energy security and carbon dioxide reduction is important to boost up the bio-power. In the long run, bio-power will depend on technological development and on competition for feedstock with food production and arable land use.

FELERION: a new approach for leakage power reduction

NASA Astrophysics Data System (ADS)

R, Anjana; Somkuwar, Ajay

2014-12-01

The circuit proposed in this paper simultaneously reduces the sub threshold leakage power and saves the state of art aspect of the logic circuits. Sleep transistors and PMOS-only logic are used to further reduce the leakage power. Sleep transistors are used as the keepers to reduce the sub threshold leakage current providing the low resistance path to the output. PMOS-only logic is used between the pull up and pull down devices to mitigate the leakage power further. Our proposed fast efficient leakage reduction circuit not only reduces the leakage current but also reduces the power dissipation. Power and delay are analyzed at the 32 nm BSIM4 model for a chain of four inverters, NAND, NOR and ISCAS-85 c17 benchmark circuits using DSCH3 and the Microwind tool. The simulation results reveal that our proposed approach mitigates leakage power by 90%-94% as compared to the conventional approach.

Research on prediction of agricultural machinery total power based on grey model optimized by genetic algorithm

NASA Astrophysics Data System (ADS)

Xie, Yan; Li, Mu; Zhou, Jin; Zheng, Chang-zheng

2009-07-01

Agricultural machinery total power is an important index to reflex and evaluate the level of agricultural mechanization. It is the power source of agricultural production, and is the main factors to enhance the comprehensive agricultural production capacity expand production scale and increase the income of the farmers. Its demand is affected by natural, economic, technological and social and other "grey" factors. Therefore, grey system theory can be used to analyze the development of agricultural machinery total power. A method based on genetic algorithm optimizing grey modeling process is introduced in this paper. This method makes full use of the advantages of the grey prediction model and characteristics of genetic algorithm to find global optimization. So the prediction model is more accurate. According to data from a province, the GM (1, 1) model for predicting agricultural machinery total power was given based on the grey system theories and genetic algorithm. The result indicates that the model can be used as agricultural machinery total power an effective tool for prediction.

The effect of greenhouse covering materials on phytochemical composition and antioxidant capacity of tomato cultivars.

PubMed

Ahmadi, Latifeh; Hao, Xiuming; Tsao, Rong

2018-02-13

The effect of light transmission (direct and diffuse) on the phenolic compounds of five tomato cultivars was investigated under controlled conditions in greenhouses covered with different covering materials. The type of covering material and type of diffusion of light simultaneously affected the reducing power of cultivars. Two-way analysis of variance showed statistically significant differences in total phenolic content for the different cultivars (P < 0.05) but not for the covering materials. Analysis by ultrahigh-performance liquid chromatography with diode array detection and liquid chromatography/tandem mass spectrometry showed the presence of major phenolic acid compounds such as chlorogenic acid, hydroxycinnamic acid/rutin, caffeic acid, ferulic acid and coumaric acid as well as flavonoid compounds such as myricetin, quercetin and naringenin. Most of the identified compounds showed a significant difference in different treatments due to both cultivar and covering material (P < 0.05). Statistical analysis showed that the type of covering material used influenced the total carotenoid and lycopene content (P < 0.05); however, the amount of lutein was not influenced by the type of covering material (P > 0.05). This study showed that the use of solar energy transmission could positively affect the reducing power of cultivars and alter the biosynthesis of certain phytochemicals that are health-beneficial. Further study could lead to applications for producing greenhouse vegetables with greater health attributes. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Chlorophytum borivilianum as potential terminator of free radicals in various in vitro oxidation systems.

PubMed

Visavadiya, Nishant P; Soni, Badrish; Dalwadi, Nirav; Madamwar, Datta

2010-04-01

Chlorophytum borivilianum is a very popular herb in traditional Indian medicine and used as a potent "Rasayana" drug in "Ayurveda" as a rejuvenator. Currently, a large body of evidence supports the key role of free radicals in diverse pathological conditions such as aging and atherosclerosis. The present investigation essentially focuses on the comprehensive account of in vitro antioxidant activity exerted by C.borivilianum root extracts (i.e., aqueous and ethanolic), to clarify the pharmacological antagonism of chemicals/metals-mediated oxidation. Graded-dose (25 to 1000 microg/ml) of aqueous extract exhibited higher antioxidant potency as evidenced by powerful nitric oxide, superoxide, hydroxyl, DPPH and ABTS(*+) radicals scavenging activity along with reducing capacity (Fe(3+)/ferricyanide complex and FRAP assays), metal chelating ability, as well as markedly suppressed the lipid peroxidation in mitochondrial fractions as compared to ethanolic extract. Further, aqueous extract significantly decreased (P < 0.05) copper-mediated human serum and kinetics of LDL oxidation, as demonstrated by prolongation of lag phase time with decline of oxidation rate, conjugated dienes, lipid hydroperoxides and thiobarbituric acid reactive substances. In addition, the total polyphenol and flavonoid contents of aqueous extract were higher than that of ethanolic extract, which indicated a positive correlation between antioxidant activity and contents of total phenols. The IC(50) values of both extracts were also compared with appropriate antioxidant standards. Overall, aqueous extract of C.borivilianum root has significant powerful antioxidant activity and may favorably affect atherosclerosis risk status by reducing LDL oxidation susceptibility.

Antioxidant and Antiproliferative Activities of Heterofucans from the Seaweed Sargassum filipendula

PubMed Central

Costa, Leandro Silva; Fidelis, Gabriel Pereira; Telles, Cinthia Beatrice Silva; Dantas-Santos, Nednaldo; Camara, Rafael Barros Gomes; Cordeiro, Sara Lima; Pereira Costa, Mariana Santana Santos; Almeida-Lima, Jailma; Melo-Silveira, Raniere Fagundes; Oliveira, Ruth Medeiros; Albuquerque, Ivan Rui Lopes; Andrade, Giulianna Paiva Viana; Rocha, Hugo Alexandre Oliveira

2011-01-01

Fucan is a term used to denominate a type of polysaccharide which contains substantial percentages of l-fucose and sulfate ester groups. We obtained five heterofucans from Sargassum filipendula by proteolytic digestion followed by sequential acetone precipitation. These heterofucans are composed mainly of fucose, glucose, glucuronic acid, galactose and sulfate. These fucans did not show anticoagulant activity in PT and aPTT tests. Their antioxidant activity was evaluated using the follow tests; total antioxidant capacity, scavenging hydroxyl and superoxide radicals, reducing power and ferrous ion [Fe(II)] chelating. All heterofucans displayed considerable activity, especially SF-1.0v which showed the most significant antioxidant potential with 90.7 ascorbic acid equivalents in a total antioxidant capacity test and similar activity when compared with vitamin C in a reducing power assay. The fucan antiproliferative activity was performed with HeLa, PC3 and HepG2 cells using MTT test. In all tested conditions the heterofucans exhibited a dose-dependent effect. The strongest inhibition was observed in HeLa cells, where SF-1.0 and SF-1.5 exhibited considerable activity with an IC50 value of 15.69 and 13.83 μM, respectively. These results clearly indicate the beneficial effect of S. filipendula polysaccharides as antiproliferative and antioxidant. Further purification steps and additional studies on structural features as well as in vivo experiments are needed to test the viability of their use as therapeutic agents. PMID:21747741

Evaluation of Phenolic Compounds and Antioxidant and Antimicrobial Activities of Some Common Herbs.

PubMed

Abdul Qadir, Muhammad; Shahzadi, Syeda Kiran; Bashir, Asad; Munir, Adil; Shahzad, Shabnam

2017-01-01

The study was designed to evaluate the phenolic, flavonoid contents and antioxidant and antimicrobial activities of onion ( Allium cepa ), garlic ( Allium sativum ), mint ( Mentha spicata ), thyme ( Thymus vulgaris ), oak ( Quercus ), aloe vera ( Aloe barbadensis Miller), and ginger ( Zingiber officinale ). All extracts showed a wide range of total phenolic contents, that is, 4.96 to 98.37 mg/100 g gallic acid equivalents, and total flavonoid contents, that is, 0.41 to 17.64 mg/100 g catechin equivalents. Antioxidant activity (AA) was determined by measuring reducing power, inhibition of peroxidation using linoleic acid system, and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity. Different extracts inhibited oxidation of linoleic acid by 16.6-84.2% while DPPH radical scavenging activity (IC 50 values) ranged from 17.8% to 79.1  μ g/mL. Reducing power at 10 mg/mL extract concentration ranged from 0.11 to 0.84 nm. Furthermore the extracts of these medicinal herbs in 80% methanol, 80% ethanol, 80% acetone, and 100% water were screened for antimicrobial activity by disc diffusion method against selected bacterial strains, Staphylococcus aureus , Escherichia coli , Bacillus subtilis , and Pasteurella multocida , and fungal strains, Aspergillus niger , Aspergillus flavus, Rhizopus solani , and Alternaria alternata . The extracts show better antimicrobial activity against bacterial strains as compared to fungal strains. Results of various assays were analyzed statistically by applying appropriate statistical methods.

Evaluation of Phenolic Compounds and Antioxidant and Antimicrobial Activities of Some Common Herbs

PubMed Central

Abdul Qadir, Muhammad; Bashir, Asad; Munir, Adil

2017-01-01

The study was designed to evaluate the phenolic, flavonoid contents and antioxidant and antimicrobial activities of onion (Allium cepa), garlic (Allium sativum), mint (Mentha spicata), thyme (Thymus vulgaris), oak (Quercus), aloe vera (Aloe barbadensis Miller), and ginger (Zingiber officinale). All extracts showed a wide range of total phenolic contents, that is, 4.96 to 98.37 mg/100 g gallic acid equivalents, and total flavonoid contents, that is, 0.41 to 17.64 mg/100 g catechin equivalents. Antioxidant activity (AA) was determined by measuring reducing power, inhibition of peroxidation using linoleic acid system, and 2,2-diphenyl-1-picrylhydrazyl radical (DPPH) scavenging activity. Different extracts inhibited oxidation of linoleic acid by 16.6–84.2% while DPPH radical scavenging activity (IC50 values) ranged from 17.8% to 79.1 μg/mL. Reducing power at 10 mg/mL extract concentration ranged from 0.11 to 0.84 nm. Furthermore the extracts of these medicinal herbs in 80% methanol, 80% ethanol, 80% acetone, and 100% water were screened for antimicrobial activity by disc diffusion method against selected bacterial strains, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pasteurella multocida, and fungal strains, Aspergillus niger, Aspergillus flavus, Rhizopus solani, and Alternaria alternata. The extracts show better antimicrobial activity against bacterial strains as compared to fungal strains. Results of various assays were analyzed statistically by applying appropriate statistical methods. PMID:28316626

Adaptations in single-leg hop biomechanics following anterior cruciate ligament reconstruction.

PubMed

Orishimo, Karl F; Kremenic, Ian J; Mullaney, Michael J; McHugh, Malachy P; Nicholas, Stephen J

2010-11-01

When a patient performs a clinically normal hop test based on distance, it cannot be assumed that the biomechanics are similar between limbs. The objective was to compare takeoff and landing biomechanics between legs in patients who have undergone anterior cruciate ligament reconstruction. Kinematics and ground reaction forces were recorded as 13 patients performed the single-leg hop on each leg. Distance hopped, joint range of motion, peak joint kinetics and the peak total extensor moment were compared between legs during both takeoff and landing. Average hop distance ratio (involved/noninvolved) was 93 ± 4%. Compared to the noninvolved side, knee motion during takeoff on the involved side was significantly reduced (P = 0.008). Peak moments and powers on the involved side were lower at the knee and higher at the ankle and hip compared with the noninvolved side (Side by Joint P = 0.011; P = 0.003, respectively). The peak total extensor moment was not different between legs (P = 0.305) despite a decrease in knee moment and increases in ankle and hip moments (Side by Joint P = 0.015). During landing, knee motion was reduced (P = 0.043), and peak power absorbed was decreased at the knee and hip and increased at the ankle on the involved side compared to the noninvolved side (P = 0.003). The compensations by other joints may indicate protective adaptations to avoid overloading the reconstructed knee.

A strategy for reducing particulate contamination on opening glass ampoules and development of evaluation methods for its application.

PubMed

Lee, Kyeong-Ryoon; Chae, Yoon-Jee; Cho, Sung-Eel; Chung, Suk-Jae

2011-12-01

A single-dose glass ampoule was developed for ease of administration. When glass ampoules are opened, resulting in contamination by particulate matter. Reducing its contamination may minimize the risk in patients due to particulates. This study reports on an attempt to reduce insoluble particulate contamination by developing methods for the precise measurement of this. A vacuum machine (VM) was used to reduce the level of insoluble particulate contamination, and a microscopy, scanning electron microscopy-energy dispersive X-ray spectrometer (SEM-EDS) and inductively coupled plasma-atomic emission spectrometer (ICP-AES) were used to evaluate the level of reduction. The method permitted the insoluble particle content to be reduced by up to 87.8 and 89.3% after opening 1 and 2 mL-ampoules, respectively. The morphology of the glass particulate contaminants was very sharp and rough, a condition that can be harmful to human health. The total weight of glass particles in the opened ampoules was determined to be 104 ± 72.9 μg and 30.5 ± 1.00 μg after opening 1 and 2 mL-ampoules when the VM was operated at highest power. The total weights were reduced to 53.6 and 50.6%, respectively for 1 and 2 mL-ampoules, compared to opening by hand. The loss of ampoule contents on opening by the VM was 6.50 and 4.67% for 1 and 2 mL-ampoules, respectively. As a result, the VM efficiently reduced glass particulate contamination and the evaluation methods used were appropriate for quantifying these levels of contamination.

Physicochemical properties and in vitro antioxidant activities of polysaccharide from Artocarpus heterophyllus Lam. pulp.

PubMed

Zhu, Kexue; Zhang, Yanjun; Nie, Shaoping; Xu, Fei; He, Shuzhen; Gong, Deming; Wu, Gang; Tan, Lehe

2017-01-02

A water-soluble polysaccharide from Artocarpus heterophyllus Lam. (jackfruit) pulp (JFP-Ps) was purified and its physicochemical properties were investigated. The in vitro antioxidant activities of JFP-Ps was evaluated by measuring DPPH and OH radicals scavenging activities, as well as reducing power. The results showed that JFP-Ps contained 79.12% of total sugar, 5.83% of protein, 15.65% of uronic acid, and 15 kinds of amino acids with high levels of Asp, Glu, Val, Leu and Lys. JFP-Ps was mainly composed of Rha, Ara, Gal, Glc, Xyl and GalA, with an average molecular weight of 1668kDa. FT-IR results showed the bands at the range of 1200-850cm -1 suggested the presence of carbohydrates in JFP-Ps. The results of antioxidant activities showed that JFP-Ps exhibited strong DPPH and OH radical scavenging activities, with a relatively lower reducing power, suggesting that JFP-Ps can be exploited as effective natural antioxidant applications in medical and food industries. Copyright © 2016 Elsevier Ltd. All rights reserved.

Insights into cholinesterase inhibitory and antioxidant activities of five Juniperus species.

PubMed

Orhan, Nilufer; Orhan, Ilkay Erdogan; Ergun, Fatma

2011-09-01

In vitro acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibitory and antioxidant activities of the aqueous and ethanol extracts of the leaves, ripe fruits, and unripe fruits of Juniperus communis ssp. nana, Juniperus oxycedrus ssp. oxycedrus, Juniperus sabina, Juniperus foetidissima, and Juniperus excelsa were investigated in the present study. Cholinesterase inhibition of the extracts was screened using ELISA microplate reader. Antioxidant activity of the extracts was tested by 2,2-diphenyl-1-picrylhydrazyl (DPPH) and superoxide radical scavenging, ferrous ion-chelating, and ferric-reducing antioxidant power (FRAP) assays. Total phenol and flavonoid contents of the extracts were determined spectrophotometrically. The extracts had low or no inhibition towards AChE, whereas the leaf aqueous extract of J. foetidissima showed the highest BChE inhibition (93.94 ± 0.01%). The leaf extracts usually exerted higher antioxidant activity. We herein describe the first study on anticholinesterase and antioxidant activity by the methods of ferrous ion-chelating, superoxide radical scavenging, and ferric-reducing antioxidant power (FRAP) assays of the mentioned Juniperus species. Copyright © 2011 Elsevier Ltd. All rights reserved.

Artificial neural network optimization of Althaea rosea seeds polysaccharides and its antioxidant activity.

PubMed

Liu, Feng; Liu, Wenhui; Tian, Shuge

2014-09-01

A combination of an orthogonal L16(4)4 test design and a three-layer artificial neural network (ANN) model was applied to optimize polysaccharides from Althaea rosea seeds extracted by hot water method. The highest optimal experimental yield of A. rosea seed polysaccharides (ARSPs) of 59.85 mg/g was obtained using three extraction numbers, 113 min extraction time, 60.0% ethanol concentration, and 1:41 solid-liquid ratio. Under these optimized conditions, the ARSP experimental yield was very close to the predicted yield of 60.07 mg/g and was higher than the orthogonal test results (40.86 mg/g). Structural characterizations were conducted using physicochemical property and FTIR analysis. In addition, the study of ARSP antioxidant activity demonstrated that polysaccharides exhibited high superoxide dismutase activity, strong reducing power, and positive scavenging activity on superoxide anion, hydroxyl radical, 2,2-diphenyl-1-picrylhydrazyl, and reducing power. Our results indicated that ANNs were efficient quantitative tools for predicting the total ARSP content. Copyright © 2014 Elsevier B.V. All rights reserved.

Chronic ozone exposure alters the secondary metabolite profile, antioxidant potential, anti-inflammatory property, and quality of red pepper fruit from Capsicum baccatum.

PubMed

Bortolin, Rafael Calixto; Caregnato, Fernanda Freitas; Divan Junior, Armando Molina; Zanotto-Filho, Alfeu; Moresco, Karla Suzana; Rios, Alessandro de Oliveira; Salvi, Aguisson de Oliveira; Ortmann, Caroline Flach; de Carvalho, Pâmela; Reginatto, Flávio Henrique; Gelain, Daniel Pens; Moreira, José Cláudio Fonseca

2016-07-01

Tropospheric ozone (O3) background concentrations have increased since pre-industrial times, reaching phytotoxic concentrations in many regions globally. However, the effect of high O3 concentrations on quality of fruit and vegetables remains unknown. Here, we evaluated whether O3 pollution alters the quality of Capsicum baccatum peppers by changing the secondary compound profiles and biological activity of the fruit. C. baccatum pepper plants were exposed to ozone for 62 days in an open-top chamber at a mean O3 concentration of 171.6µg/m(3). Capsaicin levels decreased by 50% in the pericarp, but remained unchanged in the seeds. In contrast, the total carotenoid content increased by 52.8% in the pericarp. The content of total phenolic compounds increased by 17% in the pericarp. The total antioxidant potential decreased by 87% in seeds of O3-treated plants. The seeds contributed more than the pericarp to the total radical-trapping antioxidant potential and total antioxidant reactivity. O3 treatment impaired the ferric-reducing antioxidant power of the seeds and reduced NO(•)-scavenging activity in the pericarp. However, O3 treatment increased ferrous ion-chelating activity and hydroxyl radical-scavenging activity in the pericarp. Our results confirm that O3 alters the secondary metabolite profile of C. baccatum pepper fruits and, consequently, their biological activity profile. Copyright © 2016 Elsevier Inc. All rights reserved.

Influence of high-power nonlinear consumers on electric energy losses in mining high-voltage power line

NASA Astrophysics Data System (ADS)

Averbukh, M. A.; Prasol, D. A.

2018-03-01

The article elucidates the influence of high-power nonlinear consumers on electric energy losses in a mining high-voltage power line. The object of the study was a fragment of a power supply system of a mining enterprise with hoists. The investigation has assessed the electric energy losses conditioned by nonsinusoidal currents and voltages of the power line over a single hoist operation cycle. Also, the total electric energy losses in a high-voltage power line of a mining enterprise was calculated. The energy losses due to nonsinusoidal currents and voltages over single operation cycle of the cage hoist amount to 36.358 kWh. The presence of such losses increases total technological power and energy losses in the mining high-voltage power line by approximately 5-15%. The total energy losses in the components of the mining enterprise high-voltage power line caused by nonsinusoidal voltage are significant and lead to additional expenses of the company.

Water stress induces changes in polyphenol profile and antioxidant capacity in poplar plants (Populus spp.).

PubMed

Popović, B M; Štajner, D; Ždero-Pavlović, R; Tumbas-Šaponjac, V; Čanadanović-Brunet, J; Orlović, S

2016-08-01

This paper is aimed to characterize young poplar plants under the influence of water stress provoked by polyethileneglycol 6000 (PEG 6000). Three polar genotypes (M1, B229, and PE19/66) were grown in hydroponics and subjected to 100 and 200 mOsm PEG 6000 during six days. Polyphenol characterization, two enzymatic markers and antioxidant capacity in leaves and roots were investigated in stressed plants. Total phenol content, ferric reducing antioxidant capacity (FRAP) and DPPH antiradical power (DPPH ARP) were determined for estimating total antioxidant capacity. Polyphenol oxidase (PPO) and phenylalanine ammonia lyase (PAL) were determined as enzymatic markers. Polyphenol characterization of poplar samples was performed by HPLC-PDA analysis. All results were subjected to correlation analysis and principal component analysis (PCA). Inspite of the decrease of total phenol content in investigated genotypes, as well as total antioxidant capacity, some of polyphenols were affected by stress like flavonoids chrysin, myricetine, kaempferol and isoferulic acid in roots of B229 genotype (Populus deltoides). Genotype B229 also showed the increase of antioxidant capacity and PAL activity in root and leaves under stress what could be the indicator of the adaptability of poplar plants to water stress. Significant positive correlations were obtained between PAL, antioxidant capacity as well as phenolic acids among themselves. Chemometric evaluation showed close interdependence between flavonoids, FRAP, DPPH antiradical power and both investigated enzymes of polyphenol metabolism, PAL and PPO. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Bipolar plates for PEM fuel cells

NASA Astrophysics Data System (ADS)

Middelman, E.; Kout, W.; Vogelaar, B.; Lenssen, J.; de Waal, E.

The bipolar plates are in weight and volume the major part of the PEM fuel cell stack, and are also a significant contributor to the stack costs. The bipolar plate is therefore a key component if power density has to increase and costs must come down. Three cell plate technologies are expected to reach targeted cost price levels, all having specific advantages and drawbacks. NedStack has developed a conductive composite materials and a production process for fuel cell plates (bipolar and mono-polar). The material has a high electric and thermal conductivity, and can be processed into bipolar plates by a proprietary molding process. Process cycle time has been reduced to less than 10 s, making the material and process suitable for economical mass production. Other development work to increase material efficiency resulted in thin bipolar plates with integrated cooling channels, and integrated seals, and in two-component bipolar plates. Total thickness of the bipolar plates is now less than 3 mm, and will be reduced to 2 mm in the near future. With these thin integrated plates it is possible to increase power density up to 2 kW/l and 2 kW/kg, while at the same time reducing cost by integrating other functions and less material use.

Strength training in the elderly: effects on risk factors for age-related diseases.

PubMed

Hurley, B F; Roth, S M

2000-10-01

Strength training (ST) is considered a promising intervention for reversing the loss of muscle function and the deterioration of muscle structure that is associated with advanced age. This reversal is thought to result in improvements in functional abilities and health status in the elderly by increasing muscle mass, strength and power and by increasing bone mineral density (BMD). In the past couple of decades, many studies have examined the effects of ST on risk factors for age-related diseases or disabilities. Collectively, these studies indicate that ST in the elderly: (i) is an effective intervention against sarcopenia because it produces substantial increases in the strength, mass, power and quality of skeletal muscle; (ii) can increase endurance performance; (iii) normalises blood pressure in those with high normal values; (iv) reduces insulin resistance; (v) decreases both total and intra-abdominal fat; (vi) increases resting metabolic rate in older men; (vii) prevents the loss of BMD with age; (viii) reduces risk factors for falls; and (ix) may reduce pain and improve function in those with osteoarthritis in the knee region. However, contrary to popular belief, ST does not increase maximal oxygen uptake beyond normal variations, improve lipoprotein or lipid profiles, or improve flexibility in the elderly.

High-Frequency ac Power-Distribution System

NASA Technical Reports Server (NTRS)

Hansen, Irving G.; Mildice, James

1987-01-01

Loads managed automatically under cycle-by-cycle control. 440-V rms, 20-kHz ac power system developed. System flexible, versatile, and "transparent" to user equipment, while maintaining high efficiency and low weight. Electrical source, from dc to 2,200-Hz ac converted to 440-V rms, 20-kHz, single-phase ac. Power distributed through low-inductance cables. Output power either dc or variable ac. Energy transferred per cycle reduced by factor of 50. Number of parts reduced by factor of about 5 and power loss reduced by two-thirds. Factors result in increased reliability and reduced costs. Used in any power-distribution system requiring high efficiency, high reliability, low weight, and flexibility to handle variety of sources and loads.

Application of an EGR system in a direct injection diesel engine to reduce NOx emissions

NASA Astrophysics Data System (ADS)

De Serio, D.; De Oliveira, A.; Sodré, J. R.

2016-09-01

This work presents the application of an exhaust gas recirculation (EGR) system in a direct injection diesel engine operating with diesel oil containing 7% biodiesel (B7). EGR rates of up to 10% were applied with the primary aim to reduce oxides of nitrogen (NOx) emissions. The experiments were conducted in a 44 kW diesel power generator to evaluate engine performance and emissions for different load settings. The use of EGR caused a peak pressure reduction during the combustion process and a decrease in thermal efficiency, mainly at high engine loads. A reduction of NOx emissions of up to 26% was achieved, though penalizing carbon monoxide (CO) and total hydrocarbons (THC) emissions.

A multichannel implantable telemetry system for flow, pressure, and ECG measurements

NASA Technical Reports Server (NTRS)

Fryer, T. B.; Sandler, H.; Freund, W.; Mccutcheon, E. P.; Carlson, E. L.

1975-01-01

The design, principles of operation, and performance of an implantable miniaturized (48 cu cm in volume) multiplex telemetry system for simultaneous measurement of up to eight physiological parameters (including cardiovascular data) are described. Integrated circuits are used to reduce the size, complexity, and cost of fabrication. Power consumption is reduced using recently developed complementary MOS devices. PWM technique is selected as it is relatively easy to implement, lends itself to ICs, and provides an accurate means of transmitting data. The system is totally implantable within the chest of a test animal, with no wire penetrating through the skin. It is shown that the described system permits repeated measurement of the physiological effects of a variety of interventions in awake unanesthetized animals.

Free radical scavenging and total antioxidant capacity of root extracts of Anchomanes difformis Engl. (Araceae).

PubMed

Aliyu, Abubakar B; Ibrahim, Mohammed A; Musa, Aliyu M; Musa, Aisha O; Kiplimo, Joyce J; Oyewale, Adebayo O

2013-01-01

Antioxidants activities from plants sources have attracted a wide range of interest across the world in recent times. This is due to growing concern for safe and alternative sources of antioxidants. The free radical scavenging activity using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH), reducing power assay, total antioxidant capacity of the phosphomolybdenum method and the total phenolics content using the Folin-Ciocalteu reagent were carried out on the acetone, n-butanol and methanol root extracts of Anchomanes difformis. The results of the total phenolics content expressed in mg/100 g of gallic acid equivalent (GAE) showed that the n-butanol extract has significantly (p < 0.05) higher phenolics content (381 +/- 1.13) than the methanol and acetone extracts. All the extracts displayed strong concentration dependent radical scavenging activity. It was also observed that the n-butanol extract showed higher activity of 70.87% and 78.59% at low concentrations of 31.25 microg/mL and 62.5 microg/mL, respectively, than methanol and acetone extracts. The results also showed that the n-butanol extract has strongest reducing ability which is comparable to that of gallic acid at all the concentrations tested. Phytochemical screening on the extracts revealed the presence of flavonoids, saponins, and tannins. The results suggest that n-butanol extract of the plant is very rich in antioxidant compounds worthy of further investigations.

Opportunity for offshore wind to reduce future demand for coal-fired power plants in China with consequent savings in emissions of CO2.

PubMed

Lu, Xi; McElroy, Michael B; Chen, Xinyu; Kang, Chongqing

2014-12-16

Although capacity credits for wind power have been embodied in power systems in the U.S. and Europe, the current planning framework for electricity in China continues to treat wind power as a nondispatchable source with zero contribution to firm capacity. This study adopts a rigorous reliability model for the electric power system evaluating capacity credits that should be recognized for offshore wind resources supplying power demands for Jiangsu, China. Jiangsu is an economic hub located in the Yangtze River delta accounting for 10% of the total electricity consumed in China. Demand for electricity in Jiangsu is projected to increase from 331 TWh in 2009 to 800 TWh by 2030. Given a wind penetration level of 60% for the future additional Jiangsu power supply, wind resources distributed along the offshore region of five coastal provinces in China (Shandong, Jiangsu, Shanghai, Zhejiang, and Fujian) should merit a capacity credit of 12.9%, the fraction of installed wind capacity that should be recognized to displace coal-fired systems without violating the reliability standard. In the high-coal-price scenario, with 60% wind penetration, reductions in CO2 emissions relative to a business as usual reference could be as large as 200.2 million tons of CO2 or 51.8% of the potential addition, with a cost for emissions avoided of $29.0 per ton.

Estimating the total energy demand for supra-maximal exercise using the VO2-power regression from an incremental exercise test.

PubMed

Aisbett, B; Le Rossignol, P

2003-09-01

The VO2-power regression and estimated total energy demand for a 6-minute supra-maximal exercise test was predicted from a continuous incremental exercise test. Sub-maximal VO2-power co-ordinates were established from the last 40 seconds (s) of 150-second exercise stages. The precision of the estimated total energy demand was determined using the 95% confidence interval (95% CI) of the estimated total energy demand. The linearity of the individual VO2-power regression equations was determined using Pearson's correlation coefficient. The mean 95% CI of the estimated total energy demand was 5.9 +/- 2.5 mL O2 Eq x kg(-1) x min(-1), and the mean correlation coefficient was 0.9942 +/- 0.0042. The current study contends that the sub-maximal VO2-power co-ordinates from a continuous incremental exercise test can be used to estimate supra-maximal energy demand without compromising the precision of the accumulated oxygen deficit (AOD) method.

Spatially confined low-power optically pumped ultrafast synchrotron x-ray nanodiffraction

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

Park, Joonkyu; Zhang, Qingteng; Chen, Pice

2015-08-27

The combination of ultrafast optical excitation and time-resolved synchrotron x-ray nanodiffraction provides unique insight into the photoinduced dynamics of materials, with the spatial resolution required to probe individual nanostructures or small volumes within heterogeneous materials. Optically excited x-ray nanobeam experiments are challenging because the high total optical power required for experimentally relevant optical fluences leads to mechanical instability due to heating. For a given fluence, tightly focusing the optical excitation reduces the average optical power by more than three orders of magnitude and thus ensures sufficient thermal stability for x-ray nanobeam studies. Delivering optical pulses via a scannable fiber-coupled opticalmore » objective provides a well-defined excitation geometry during rotation and translation of the sample and allows the selective excitation of isolated areas within the sample. Finally, experimental studies of the photoinduced lattice dynamics of a 35 nm BiFeO 3 thin film on a SrTiO 3 substrate demonstrate the potential to excite and probe nanoscale volumes.« less

The power of brand equity: Exploiting a singular incumbent advantage

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

Almquist, E.; Piotroski, S.A.

The US utility ``brandscape`` resembles feudal Europe: There are numerous adjacent fiefdoms where the brand equity within each falls off precipitously outside territory borders. Those who want to ``go national`` face a protracted, expensive task dislodging local incumbents. With the onset of competition in retail electric power markets, America`s last great deregulation is well under way. Customers are pressing their suppliers to reduce energy bills by opening markets to competition. Deregulation of power generation, which has moved quickly in recent years throughout North America and Europe, is eroding the traditional pillars of value: franchise protection, cost-based pricing, and rate-of-return regulation.more » The stakes are high for incumbent utilities, given that electric sales in the United States alone total more than $200 billion, greater than sales in telecommunications, air transportation, or railroads. Add in natural gas ($5 billion or so) and related energy products and services, and it is clear why upstart entrepreneurs and outsider firms are attracted to the opportunities opened up by deregulation.« less

Ultracompliant Heterogeneous Copper-Tin Nanowire Arrays Making a Supersolder.

PubMed

Gong, Wei; Li, Pengfei; Zhang, Yunheng; Feng, Xuhui; Major, Joshua; DeVoto, Douglas; Paret, Paul; King, Charles; Narumanchi, Sreekant; Shen, Sheng

2018-06-13

Due to the substantial increase in power density, thermal interface resistance that can constitute more than 50% of the total thermal resistance has generally become a bottleneck for thermal management in electronics. However, conventional thermal interface materials (TIMs) such as solder, epoxy, gel, and grease cannot fulfill the requirements of electronics for high-power and long-term operation. Here, we demonstrate a high-performance TIM consisting of a heterogeneous copper-tin nanowire array, which we term "supersolder" to emulate the role of conventional solders in bonding various surfaces. The supersolder is ultracompliant with a shear modulus 2-3 orders of magnitude lower than traditional solders and can reduce the thermal resistance by two times as compared with the state-of-the-art TIMs. This supersolder also exhibits excellent long-term reliability with >1200 thermal cycles over a wide temperature range. By resolving this critical thermal bottleneck, the supersolder enables electronic systems, ranging from microelectronics and portable electronics to massive data centers, to operate at lower temperatures with higher power density and reliability.

Sequential modelling of ICRF wave near RF fields and asymptotic RF sheaths description for AUG ICRF antennas

NASA Astrophysics Data System (ADS)

Jacquot, Jonathan; Tierens, Wouter; Zhang, Wei; Bobkov, Volodymyr; Colas, Laurent; Noterdaeme, Jean-Marie

2017-10-01

A sequence of simulations is performed with RAPLICASOL and SSWICH to compare two AUG ICRF antennas. RAPLICASOL outputs have been used as input to SSWICH-SW for the AUG ICRF antennas. Using parallel electric field maps and the scattering matrix produced by RAPLICASOL, SSWICH-SW, reduced to its asymptotic part, is able to produce a 2D radial/poloidal map of the DC plasma potential accounting for the antenna input settings (total power, power balance, phasing). Two models of antennas are compared: 2-strap antenna vs 3-strap antenna. The 2D DC potential structures are correlated to structures of the parallel electric field map for different phasing and power balance. The overall DC plasma potential on the 3-strap antenna is lower due to better global RF currents compensation. Spatial proximity between regions of high RF electric field and regions where high DC plasma potentials are observed is an important factor for sheath rectification.

Low-Cost Nested-MIMO Array for Large-Scale Wireless Sensor Applications.

PubMed

Zhang, Duo; Wu, Wen; Fang, Dagang; Wang, Wenqin; Cui, Can

2017-05-12

In modern communication and radar applications, large-scale sensor arrays have increasingly been used to improve the performance of a system. However, the hardware cost and circuit power consumption scale linearly with the number of sensors, which makes the whole system expensive and power-hungry. This paper presents a low-cost nested multiple-input multiple-output (MIMO) array, which is capable of providing O ( 2 N 2 ) degrees of freedom (DOF) with O ( N ) physical sensors. The sensor locations of the proposed array have closed-form expressions. Thus, the aperture size and number of DOF can be predicted as a function of the total number of sensors. Additionally, with the help of time-sequence-phase-weighting (TSPW) technology, only one receiver channel is required for sampling the signals received by all of the sensors, which is conducive to reducing the hardware cost and power consumption. Numerical simulation results demonstrate the effectiveness and superiority of the proposed array.

Low-Cost Nested-MIMO Array for Large-Scale Wireless Sensor Applications

PubMed Central

Zhang, Duo; Wu, Wen; Fang, Dagang; Wang, Wenqin; Cui, Can

2017-01-01

In modern communication and radar applications, large-scale sensor arrays have increasingly been used to improve the performance of a system. However, the hardware cost and circuit power consumption scale linearly with the number of sensors, which makes the whole system expensive and power-hungry. This paper presents a low-cost nested multiple-input multiple-output (MIMO) array, which is capable of providing O(2N2) degrees of freedom (DOF) with O(N) physical sensors. The sensor locations of the proposed array have closed-form expressions. Thus, the aperture size and number of DOF can be predicted as a function of the total number of sensors. Additionally, with the help of time-sequence-phase-weighting (TSPW) technology, only one receiver channel is required for sampling the signals received by all of the sensors, which is conducive to reducing the hardware cost and power consumption. Numerical simulation results demonstrate the effectiveness and superiority of the proposed array. PMID:28498329

Antioxidant and antibacterial activity of six edible wild plants (Sonchus spp.) in China.

PubMed

Xia, Dao-Zong; Yu, Xin-Fen; Zhu, Zhuo-Ying; Zou, Zhuang-Dan

2011-12-01

The total phenolic and flavonoid, antioxidant and antibacterial activities of six Sonchus wild vegetables (Sonchus oleraceus L., Sonchus arvensis L., Sonchus asper (L.) Hill., Sonchus uliginosus M.B., Sonchus brachyotus DC. and Sonchus lingianus Shih) in China were investigated. The results revealed that S. arvensis extract and S. oleraceus extract contained the highest amount of phenolic and flavonoid, respectively. Among the methanol extracts of six Sonchus species, S. arvensis extract exhibited the highest radical (DPPH and ABTS+ scavenging power and lipid peroxidation inhibitory power. It also exhibited the highest reducing power at 500 µg mL⁻¹ by A (700) = 0.80. The results of antibacterial test indicated that the S. oleraceus extract showed higher activity than the other five Sonchus wild vegetables extracts, both in Gram-negative bacteria (Escherichia coli, Salmonella enterica and Vibrio parahaemolyticus) and in a Gram-positive bacterium (Staphylococcus aureus). These results indicate that Sonchus wild food plants might be applicable in natural medicine and healthy food.

Quinary excitation method for pulse compression ultrasound measurements.

PubMed

Cowell, D M J; Freear, S

2008-04-01

A novel switched excitation method for linear frequency modulated excitation of ultrasonic transducers in pulse compression systems is presented that is simple to realise, yet provides reduced signal sidelobes at the output of the matched filter compared to bipolar pseudo-chirp excitation. Pulse compression signal sidelobes are reduced through the use of simple amplitude tapering at the beginning and end of the excitation duration. Amplitude tapering using switched excitation is realised through the use of intermediate voltage switching levels, half that of the main excitation voltages. In total five excitation voltages are used creating a quinary excitation system. The absence of analogue signal generation and power amplifiers renders the excitation method attractive for applications with requirements such as a high channel count or low cost per channel. A systematic study of switched linear frequency modulated excitation methods with simulated and laboratory based experimental verification is presented for 2.25 MHz non-destructive testing immersion transducers. The signal to sidelobe noise level of compressed waveforms generated using quinary and bipolar pseudo-chirp excitation are investigated for transmission through a 0.5m water and kaolin slurry channel. Quinary linear frequency modulated excitation consistently reduces signal sidelobe power compared to bipolar excitation methods. Experimental results for transmission between two 2.25 MHz transducers separated by a 0.5m channel of water and 5% kaolin suspension shows improvements in signal to sidelobe noise power in the order of 7-8 dB. The reported quinary switched method for linear frequency modulated excitation provides improved performance compared to pseudo-chirp excitation without the need for high performance excitation amplifiers.

Learning to walk with an adaptive gain proportional myoelectric controller for a robotic ankle exoskeleton.

PubMed

Koller, Jeffrey R; Jacobs, Daniel A; Ferris, Daniel P; Remy, C David

2015-11-04

Robotic ankle exoskeletons can provide assistance to users and reduce metabolic power during walking. Our research group has investigated the use of proportional myoelectric control for controlling robotic ankle exoskeletons. Previously, these controllers have relied on a constant gain to map user's muscle activity to actuation control signals. A constant gain may act as a constraint on the user, so we designed a controller that dynamically adapts the gain to the user's myoelectric amplitude. We hypothesized that an adaptive gain proportional myoelectric controller would reduce metabolic energy expenditure compared to walking with the ankle exoskeleton unpowered because users could choose their preferred control gain. We tested eight healthy subjects walking with the adaptive gain proportional myoelectric controller with bilateral ankle exoskeletons. The adaptive gain was updated each stride such that on average the user's peak muscle activity was mapped to maximal power output of the exoskeleton. All subjects participated in three identical training sessions where they walked on a treadmill for 50 minutes (30 minutes of which the exoskeleton was powered) at 1.2 ms(-1). We calculated and analyzed metabolic energy consumption, muscle recruitment, inverse kinematics, inverse dynamics, and exoskeleton mechanics. Using our controller, subjects achieved a metabolic reduction similar to that seen in previous work in about a third of the training time. The resulting controller gain was lower than that seen in previous work (β=1.50±0.14 versus a constant β=2). The adapted gain allowed users more total ankle joint power than that of unassisted walking, increasing ankle power in exchange for a decrease in hip power. Our findings indicate that humans prefer to walk with greater ankle mechanical power output than their unassisted gait when provided with an ankle exoskeleton using an adaptive controller. This suggests that robotic assistance from an exoskeleton can allow humans to adopt gait patterns different from their normal choices for locomotion. In our specific experiment, subjects increased ankle power and decreased hip power to walk with a reduction in metabolic cost. Future exoskeleton devices that rely on proportional myolectric control are likely to demonstrate improved performance by including an adaptive gain.

Proximal fiber tip damage during Holmium:YAG and thulium fiber laser ablation of kidney stones

NASA Astrophysics Data System (ADS)

Wilson, Christopher R.; Hardy, Luke A.; Irby, Pierce B.; Fried, Nathaniel M.

2016-02-01

The Thulium fiber laser (TFL) is being studied as an alternative to Holmium:YAG laser for lithotripsy. TFL beam originates within an 18-μm-core thulium doped silica fiber, and its near single mode, Gaussian beam profile enables transmission of higher laser power through smaller fibers than possible during Holmium laser lithotripsy. This study examines whether TFL beam profile also reduces proximal fiber tip damage compared to Holmium laser multimodal beam. TFL beam at wavelength of 1908 nm was coupled into 105-μm-core silica fibers, with 35-mJ energy, 500-μs pulse duration, and pulse rates of 50-500 Hz. For each pulse rate, 500,000 pulses were delivered. Magnified images of proximal fiber surfaces were taken before and after each trial. For comparison, 20 single-use, 270-μm-core fibers were collected after clinical Holmium laser lithotripsy procedures using standard settings (600 mJ, 350 μs, 6 Hz). Total laser energy, number of laser pulses, and laser irradiation time were recorded, and fibers were rated for damage. For TFL studies, output power was stable, and no proximal fiber damage was observed after delivery of 500,000 pulses at settings up to 35 mJ, 500 Hz, and 17.5 W average power. In contrast, confocal microscopy images of fiber tips after Holmium lithotripsy showed proximal fiber tip degradation in all 20 fibers. The proximal fiber tip of a 105-μm-core fiber transmitted 17.5 W of TFL power without degradation, compared to degradation of 270-μm-core fibers after transmission of 3.6 W of Holmium laser power. The smaller and more uniform TFL beam profile may improve fiber lifetime, and potentially reduce costs for the surgical disposables as well.

Optimum sample size allocation to minimize cost or maximize power for the two-sample trimmed mean test.

PubMed

Guo, Jiin-Huarng; Luh, Wei-Ming

2009-05-01

When planning a study, sample size determination is one of the most important tasks facing the researcher. The size will depend on the purpose of the study, the cost limitations, and the nature of the data. By specifying the standard deviation ratio and/or the sample size ratio, the present study considers the problem of heterogeneous variances and non-normality for Yuen's two-group test and develops sample size formulas to minimize the total cost or maximize the power of the test. For a given power, the sample size allocation ratio can be manipulated so that the proposed formulas can minimize the total cost, the total sample size, or the sum of total sample size and total cost. On the other hand, for a given total cost, the optimum sample size allocation ratio can maximize the statistical power of the test. After the sample size is determined, the present simulation applies Yuen's test to the sample generated, and then the procedure is validated in terms of Type I errors and power. Simulation results show that the proposed formulas can control Type I errors and achieve the desired power under the various conditions specified. Finally, the implications for determining sample sizes in experimental studies and future research are discussed.

Non-Cooled Power System for Venus Lander

NASA Technical Reports Server (NTRS)

Salazar, Denise; Landis, Geoffrey A.; Colozza, Anthony J.

2014-01-01

The Planetary Science Decadal Survey of 2013-2022 stated that the exploration of Venus is of significant interest. Studying the seismic activity of the planet is of particular importance because the findings can be compared to the seismic activity of Earth. Further, the geological and atmospheric properties of Venus will shed light into the past and future of Earth. This paper presents a radioisotope power system (RPS) design for a small low-power Venus lander. The feasibility of the new power system is then compared to that of primary batteries. A requirement for the power source system is to avoid moving parts in order to not interfere with the primary objective of the mission - to collect data about the seismic activity of Venus using a seismometer. The target mission duration of the lander is 117 days, a significant leap from Venera 13, the longest-lived lander on the surface of Venus, which survived for 2 hours. One major assumption for this mission design is that the power source system will not provide cooling to the other components of the lander. This assumption is based on high-temperature electronics technology that will enable the electronics and components of the lander to operate at Venus surface temperature. For the proposed RPS, a customized General Purpose Heat Source Radioisotope Thermoelectric Generator (GPHSRTG) is designed and analyzed. The GPHS-RTG is chosen primarily because it has no moving parts and it is capable of operating for long duration missions on the order of years. This power system is modeled as a spherical structure for a fundamental thermal analysis. The total mass and electrical output of the system are calculated to be 24 kilograms and 26 Watts, respectively. An alternative design for a battery-based power system uses Sodium Sulfur batteries. To deliver a similar electrical output for 117 days, the battery mass is calculated to be 234 kilograms. Reducing mission duration or power required will reduce the required battery mass. Finally, the advantages and disadvantages of both power systems with regard to science return, risk, and cost are briefly compared. The design of the radioisotope power system is considerably riskier because it is novel and would require additional years of further refinement, manufacturing, safety analysis, and testing that the primary batteries do not need. However, the lifetime of the radioisotope power system makes its science return more promising.

Role of natural gas in meeting an electric sector emissions ...

EPA Pesticide Factsheets

With advances in natural gas extraction technologies, there is an increase in availability of domestic natural gas, and natural gas is gaining a larger share of use as a fuel in electricity production. At the power plant, natural gas is a cleaner burning fuel than coal, but uncertainties exist in the amount of methane leakage occurring upstream in the extraction and production of natural gas. At high leakage levels, these methane emissions could outweigh the benefits of switching from coal to natural gas. This analysis uses the MARKAL linear optimization model to compare the carbon emissions profiles and system-wide global warming potential of the U.S. energy system over a series of model runs in which the power sector is asked to meet a specific CO2 reduction target and the availability of natural gas changes. Scenarios are run with a range of upstream methane emission leakage rates from natural gas production. While the total CO2 emissions are reduced in most scenarios, total greenhouse gas emissions show an increase or no change when both natural gas availability and methane emissions from natural gas production are high. Article presents summary of results from an analyses of natural gas resource availability and power sector emissions reduction strategies under different estimates of methane leakage rates during natural gas extraction and production. This was study was undertaken as part of the Energy Modeling Forum Study #31:

Phytochemical Properties and Antioxidant Activities of Extracts from Wild Blueberries and Lingonberries.

PubMed

Dróżdż, Paulina; Šėžienė, Vaida; Pyrzynska, Krystyna

2017-12-01

Among Vaccinium species, blueberries (Vaccinium myrtillus L.) and lingonberries (Vaccinium vitis-idaea) are popular in the human diet. In this study, total phenolic, total flavonoid and total monomeric anthocyanin contents in the ethanol-water extracts of blueberry and lingonberry fruits grown wild in the forests in the central region of Poland were assayed. Antioxidant activities of the extracts from each plant were also evaluated for scavenging ability on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and reducing power by cupric reducing antioxidant capacity (CUPRAC) method. Total phenolics in the blueberry extracts ranged from 4.58 to 5.28 mg GAE CE/g fw. The extracts from lingonberry fruits contained higher total contents of phenolic compounds (5.82-7.60 mg GAE/g fw) as well as total flavonoids (5.22-6.47 μmol CE/g fw) than those from blueberries (3.74-4.18 μmol CE/g fw). For the total monomeric anthocyanin contents, the blueberry extracts presented significantly higher values (3.01-3.93 mg cyanidin-3-glucoside (C3G) equivalent/g fw) in comparison to the lingonberry extracts (0.32-0.47). Blueberry extracts exhibited higher antioxidant activity measured by both assays in comparison to lingonberry extracts. Water extracts from fresh and dried fruits also exhibited significant antioxidant activities for both types of berries. Considering the health benefits that have been associated with polyphenolic consumption, these fruits could appear as a good source of this group of phytochemical compounds for their direct consumption or their use as ingredients for the design of new food products or food supplements.

Generating Electricity by Harnessing Air That Flows Around a Skyscraper by Using Bernoulli's Principle And The Venturi Effect w/Special Emphasis on Biomimicry

NASA Astrophysics Data System (ADS)

Pizzolato, R.

2017-12-01

Can skyscrapers become carbon neutral using wind that flows around them to power wind turbines? I say YES! To test this idea, I constructed a venturi to capture wind flowing around a skyscraper by applying Bernoulli's Principle and the Venturi Effect to power vertical axis wind turbines (VAWT) to generate electricity. The model was constructed from polycarbonate. Turbine blades (45°&60°) carved from balsa wood with square edges, airfoils, and trailing edge tubercles (Humpback whales-biomimicry) were tested in a wind tunnel. Output was measured using Vernier's Logger Pro 3.12 software, energy and wind sensors. Voltage (mV), current (mA), power (mW) and total energy (mJ) produced at winds speeds of 3.9, 5, 7.5 and 10 m/s were recorded. 10 trials were performed for each blade angle and each blade design for a total of 240 trials. Trials were 100 seconds long and recorded at a rate of 10 measurements/second. The blades that showed the largest %Δ in total average energy output (mJ) were the 60° airfoil blades w/ tubercles on the trailing edge (20,490 mJ) when compared to 60° square edged blades (7,021 mJ). The trend of the data showed that the airfoils w/tubercles (45° & 60°) outperformed all the other blade designs at wind speeds of 7.5 m/s and 10 m/s. Also, the 45° airfoil w/tubercles produced the highest output of 25,136 mJ! This was possibly due to the improved aerodynamics of the tubercle blades which led to improvements in lift and a reduction in drag. The data shows that turbine blades that incorporate biomimicry in their design result in more efficient power output. Through biomimicry, it is possible to efficiently generate electricity with a skyscraper and reduce our dependence upon fossil fuels!

Nitrogen oxide emission calculation for post-Panamax container ships by using engine operation power probability as weighting factor: A slow-steaming case.

PubMed

Cheng, Chih-Wen; Hua, Jian; Hwang, Daw-Shang

2018-06-01

In this study, the nitrogen oxide (NO x ) emission factors and total NO x emissions of two groups of post-Panamax container ships operating on a long-term slow-steaming basis along Euro-Asian routes were calculated using both the probability density function of engine power levels and the NO x emission function. The main engines of the five sister ships in Group I satisfied the Tier I emission limit stipulated in MARPOL (International Convention for the Prevention of Pollution from Ships) Annex VI, and those in Group II satisfied the Tier II limit. The calculated NO x emission factors of the Group I and Group II ships were 14.73 and 17.85 g/kWhr, respectively. The total NO x emissions of the Group II ships were determined to be 4.4% greater than those of the Group I ships. When the Tier II certification value was used to calculate the average total NO x emissions of Group II engines, the result was lower than the actual value by 21.9%. Although fuel consumption and carbon dioxide (CO 2 ) emissions were increased by 1.76% because of slow steaming, the NO x emissions were markedly reduced by 17.2%. The proposed method is more effective and accurate than the NO x Technical Code 2008. Furthermore, it can be more appropriately applied to determine the NO x emissions of international shipping inventory. The usage of operating power probability density function of diesel engines as the weighting factor and the NO x emission function obtained from test bed for calculating NO x emissions is more accurate and practical. The proposed method is suitable for all types and purposes of diesel engines, irrespective of their operating power level. The method can be used to effectively determine the NO x emissions of international shipping and inventory applications and should be considered in determining the carbon tax to be imposed in the future.

Estimated use of water in the United States in 2015

USGS Publications Warehouse

Dieter, Cheryl A.; Maupin, Molly A.; Caldwell, Rodney R.; Harris, Melissa A.; Ivahnenko, Tamara I.; Lovelace, John K.; Barber, Nancy L.; Linsey, Kristin S.

2018-06-19

Water use in the United States in 2015 was estimated to be about 322 billion gallons per day (Bgal/d), which was 9 percent less than in 2010. The 2015 estimates put total withdrawals at the lowest level since before 1970, following the same overall trend of decreasing total withdrawals observed from 2005 to 2010. Freshwater withdrawals were 281 Bgal/d, or 87 percent of total withdrawals, and saline-water withdrawals were 41.0 Bgal/d, or 13 percent of total withdrawals. Fresh surface-water withdrawals (198 Bgal/d) were 14 percent less than in 2010, and fresh groundwater withdrawals (82.3 Bgal/day) were about 8 percent greater than in 2010. Saline surface-water withdrawals were 38.6 Bgal/d, or 14 percent less than in 2010. Total saline groundwater withdrawals in 2015 were 2.34 Bgal/d, mostly for mining use.Thermoelectric power and irrigation remained the two largest uses of water in 2015, and total withdrawals decreased for thermoelectric power but increased for irrigation. With­drawals in 2015 for thermoelectric power were 18 percent less and withdrawals for irrigation were 2 percent greater than in 2010. Similarly, other uses showed reductions compared to 2010, specifically public supply (–7 percent), self-supplied domestic (–8 percent), self-supplied industrial (–9 percent), and aquaculture (–16 percent). In addition to irrigation (2 percent), mining (1 percent) reported larger withdrawals in 2015 than in 2010. Livestock withdrawals remained essentially the same in 2015 compared to 2010 (0 percent change). Thermoelectric power, irrigation, and public-supply withdrawals accounted for 90 percent of total withdrawals in 2015.Withdrawals for thermoelectric power were 133 Bgal/d in 2015 and represented the lowest levels since before 1970. Surface-water withdrawals accounted for more than 99 percent of total thermoelectric-power withdrawals, and 72 percent of those surface-water withdrawals were from freshwater sources. Saline surface-water withdrawals for thermoelectric power accounted for 97 percent of total saline surface-water withdrawals for all uses. Thermoelectric-power withdrawals accounted for 41 percent of total withdrawals for all uses, and freshwater withdrawals for thermoelectric power accounted for 34 percent of the total freshwater withdrawals for all uses. Total consumptive use for thermoelectric power was 4.31 Bgal/d in 2015 or 3 percent of the total thermoelectric-power withdrawals.Irrigation withdrawals were 118 Bgal/d in 2015, an increase of 2 percent from 2010 (116 Bgal/d), but were approximately equal to withdrawals estimated in the 1960s. Irrigation withdrawals, all freshwater, accounted for 42 percent of total freshwater withdrawals for all uses and 64 percent of total freshwater withdrawals for all uses excluding thermoelectric power. Surface-water withdrawals (60.9 Bgal/d) accounted for 52 percent of the total irrigation withdrawals, or about 8 percent less than in 2010. Ground­water withdrawals for irrigation were 57.2 Bgal/d in 2015, about 16 percent more than in 2010. About 63,500 thousand acres (or 63.5 million acres) were irrigated in 2015, an increase from 2010 of about 1,130 thousand acres (2 percent). The number of acres irrigated using sprinkler and microirrigation systems accounted for 63 percent of the total irrigated lands in 2015. Total consumptive use for irrigation was 73.2 Bgal/d in 2015 or 62 percent of the total use (withdrawals and reclaimed wastewater).Public-supply withdrawals in 2015 were 39.0 Bgal/d, or 7 percent less than in 2010, continuing the declines observed from 2005 to 2010. Total population in the United States increased from 312.6 million people in 2010 to 325.0 million people in 2015, an increase of 4 percent. Public-supply withdrawals accounted for 14 percent of the total freshwater withdrawals for all uses and 21 percent of freshwater with­drawals for all uses, excluding thermoelectric power. The number of people that received potable water from public-supply facilities in 2015 was 283 million, or about 87 percent of the total United States population. This percentage is 1 percent greater than in 2010. Self-supplied domestic withdrawals were 3.26 Bgal/d, or 8 percent less than in 2010. More than 98 percent of the self-supplied domestic withdrawals were from groundwater sources.Self-supplied industrial withdrawals were 14.8 Bgal/d in 2015, a 9 percent decline from 2010, continuing the downward trend since the peak of 47 Bgal/d in 1970. Total self-supplied industrial withdrawals were 5 percent of total withdrawals for all uses and 8 percent of total withdrawals for all uses, excluding thermoelectric power. Most of the total self-supplied industrial withdrawals were from surface-water sources (82 percent), and nearly all (94 percent) of those surface-water withdrawals were from freshwater sources. Nearly all of the groundwater withdrawals for self-supplied industrial use (98 percent) were from freshwater sources.Total aquaculture withdrawals were 7.55 Bgal/d in 2015, or 16 percent less than in 2010, and surface water was the primary source (79 percent). Most of the surface-water withdrawals occurred at facilities that operated flow-through raceways, which returned the water to the source directly after use. Aquaculture withdrawals accounted for 2 percent of the total withdrawals for all uses and 4 percent of the total withdrawals for all uses, excluding thermoelectric.Total mining withdrawals in 2015 were 4.00 Bgal/d, or about 1 percent of total withdrawals from all uses and 2 percent of total withdrawals from all uses, excluding thermoelectric. Mining withdrawals increased 1 percent from 2010 to 2015. Groundwater withdrawals accounted for 72 percent of the total mining withdrawals, and most of the groundwater was saline (65 percent). Most (77 percent) of the surface-water withdrawals for mining was freshwater.Livestock withdrawals in 2015 were 2.00 Bgal/d, the same as in 2010. All livestock withdrawals were from freshwater sources, mostly from groundwater (62 percent). Livestock withdrawals accounted for about 1 percent of total freshwater withdrawals for all uses, excluding thermoelectric power.In 2015, more than 50 percent of the total withdrawals in the United States were accounted for by 12 States (California, Texas, Idaho, Florida, Arkansas, New York, Illinois, Colorado, North Carolina, Michigan, Montana, and Nebraska). California accounted for almost 9 percent of the total withdrawals and 9 percent of freshwater withdrawals in the United States, predominantly for irrigation. Texas accounted for almost 7 percent of total withdrawals, predominantly for thermoelectric power, irrigation, and public supply. Florida accounted for 23 percent of the total saline-water withdrawals in the United States, mostly from surface-water sources for thermoelectric power. Texas and California accounted for 59 percent of the total saline groundwater withdrawals in the United States, mostly for mining.

Extracts of Agrimonia eupatoria L. as sources of biologically active compounds and evaluation of their antioxidant, antimicrobial, and antibiofilm activities.

PubMed

Muruzović, Mirjana Ž; Mladenović, Katarina G; Stefanović, Olgica D; Vasić, Sava M; Čomić, Ljiljana R

2016-07-01

In this study, we determined the concentration of total phenols, flavonoids, tannins, and proanthocyanidins in the water, diethyl ether, acetone, and ethanol extracts of Agrimonia eupatoria L. We also investigated the antioxidant activity of these extracts using two methods [2,2-diphenyl-1-picrylhydrazyl (DPPH) and reducing power] and their in vitro antimicrobial (antibacterial and antifungal) activity on some selected species of bacteria and fungi. In addition, the effects of the acetone and water extracts on the inhibition of biofilm formation of Proteus mirabilis and Pseudomonas aeruginosa were investigated using the crystal violet method. The concentration of total phenols was measured according to the Folin-Ciocalteu method and the values obtained ranged from 19.61 mgGA/g to 220.31 mgGA/g. The concentration of flavonoids was examined by the aluminum chloride method and the values obtained ranged from 20.58 mgRU/g to 97.06 mgRU/g. The total tannins concentration was measured by the polyvinylpolypyrrolidone method and the values obtained ranged from 3.06 mgGA/g to 207.27 mgGA/g. The concentration of proanthocyanidins was determined by the butanol-HCl method and the values obtained ranged from 4.15 CChE/g to 103.72 CChE/g. Among the various extracts studied, the acetone extract exhibited good antioxidant activity (97.13%, as determined by the DPPH method). The acetone extract was active in the absorbance value range from 2.2665 to 0.2495 (as determined by the reducing power method). The strongest antimicrobial activity was detected on G + bacteria, especially on probiotic species, and the acetone extract demonstrated the highest activity. Biofilm inhibitory concentration required to reduce biofilm coverage by 50% values for acetone extract was 4315 μg/mL for P. mirabilis and 4469.5 μg/mL for P. aeruginosa. The results provide a basis for further research of this plant species. Copyright © 2016. Published by Elsevier B.V.

On the Path to SunShot - The Environmental and Public Health Benefits of Achieving High Penetrations of Solar Energy in the United States

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

Wiser, Ryan; Mai, Trieu; Millstein, Dev

Monetizing the environmental health benefits of solar could add ~3.5¢/kWh to the value of solar energy (see Wiser et al. 2016). The monetary impacts due to environmental degradation and public health impacts seem far removed from the apparent “sticker price” of electricity. Yet quantifying these impacts is essential to understanding the true costs and benefits of solar and conventional generating technologies. Compared with fossil fuel generators, PV and CSP produce far lower lifecycle levels of greenhouse gas (GHG) emissions and harmful pollutants including fine particular matter (PM2.5), sulfur dioxide (SO2), and nitrogen oxides (NOx). Achieving the SunShot-level solar deployment targets—14%more » of U.S. electricity demand met by solar in 2030 and 27% in 2050—could reduce cumulative power-sector GHG emissions by 10% between 2015 and 2050, resulting in savings of $238–$252 billion. This is equivalent to 2.0–2.2 cents per kilowatt-hour of solar installed (¢/kWh-solar). Similarly, realizing these levels of solar deployment could reduce cumulative power-sector emissions of PM2.5 by 8%, SO2 by 9%, and NOx by 11% between 2015 and 2050. This could produce $167 billion in savings from lower future health and environmental damages, or 1.4¢/kWh-solar—while also preventing 25,000–59,000 premature deaths. To put this in perspective, the estimated 3.5¢/kWh-solar in benefits due to SunShot-level solar deployment is approximately equal to the additional LCOE reduction needed to make unsubsidized utility-scale solar competitive with conventional generators today. In addition, water savings from achieving the SunShot goals, could result in the 2015–2050 cumulative savings of 4% of total power-sector withdrawals and 9% of total power-sector consumption—a particularly important consideration for arid states where substantial solar will be deployed. Improving public health and the environment is but one aspect of solar’s many costs and benefits. Clearly, however, the assignment of value« less