Circuit dependence of the diameter of pulsed positive streamers in air

Energy Technology Data Exchange (ETDEWEB)

Briels, T M P [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600MB Eindhoven (Netherlands); Kos, J [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600MB Eindhoven (Netherlands); Veldhuizen, E M van [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600MB Eindhoven (Netherlands); Ebert, U [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600MB Eindhoven (Netherlands)

2006-12-21

The diameter and branching structure of positive streamers in ambient air are investigated with a fast iCCD camera. We use different pulsed power circuits and find that they generate different spatial streamer structures. The electrodes have a point-plane geometry and a distance of 40 or 80 mm, and the peak voltages over the discharge gap are up to 60 kV. Depending on circuit and peak voltage, we observe streamers with diameters varying gradually between 0.2 and 2.5 mm. The streamer velocity increases with the diameter, ranging from 0.07 to 1.5 mm ns{sup -1}, while the current density within the streamers stays almost constant. The thicker streamers extend much further before they branch than the thinner ones. The pulsed power supplies are a switched capacitor supply with an internal resistance of 1 k{omega} and a transmission line transformer supply with an impedance of 200 {omega}; additional resistors change the impedance as well as the voltage rise time in the case of the capacitor supply. We observe that short rise times and low impedance create thick streamers close to the pointed electrode, while a longer rise time as well as a higher impedance create thinner streamers at the same peak voltage over the discharge.

Circuit dependence of the diameter of pulsed positive streamers in air

International Nuclear Information System (INIS)

Briels, T M P; Kos, J; Veldhuizen, E M van; Ebert, U

2006-01-01

The diameter and branching structure of positive streamers in ambient air are investigated with a fast iCCD camera. We use different pulsed power circuits and find that they generate different spatial streamer structures. The electrodes have a point-plane geometry and a distance of 40 or 80 mm, and the peak voltages over the discharge gap are up to 60 kV. Depending on circuit and peak voltage, we observe streamers with diameters varying gradually between 0.2 and 2.5 mm. The streamer velocity increases with the diameter, ranging from 0.07 to 1.5 mm ns -1 , while the current density within the streamers stays almost constant. The thicker streamers extend much further before they branch than the thinner ones. The pulsed power supplies are a switched capacitor supply with an internal resistance of 1 kΩ and a transmission line transformer supply with an impedance of 200 Ω; additional resistors change the impedance as well as the voltage rise time in the case of the capacitor supply. We observe that short rise times and low impedance create thick streamers close to the pointed electrode, while a longer rise time as well as a higher impedance create thinner streamers at the same peak voltage over the discharge

Hepatocellular carcinomas 2–3 cm in diameter: Transarterial chemoembolization plus radiofrequency ablation vs. radiofrequency ablation alone

International Nuclear Information System (INIS)

Kim, Jong Woo; Kim, Jin Hyoung; Won, Hyung Jin; Shin, Yong Moon; Yoon, Hyun-Ki; Sung, Kyu-Bo; Kim, Pyo Nyun

2012-01-01

Objective: There is debate whether transarterial chemoembolization (TACE) plus radiofrequency ablation (RFA) is more effective than RFA alone in the treatment of patients with small hepatocellular carcinoma (HCC). We therefore retrospectively compared these treatments in patients with HCCs of diameter 2–3 cm. Materials and methods: Outcomes, including tumor progression, survival rates, and major complications, were compared in 83 patients (83 tumors) treated with combined TACE and RFA and in 231 patients (231 tumors) treated with RFA alone. Results: Median follow-up periods were similar in the TACE + RFA and RFA alone groups (37 vs. 38 months). During follow-up, local tumor progression was observed in 16% and 41% of tumors, respectively. The 1, 3, and 5 year local tumor progression-free survival rates were significantly higher in the TACE + RFA group (95%, 86%, and 83%, respectively) than in the RFA-alone group (78%, 61%, and 53%, respectively; P < 0.001). The 1, 3, and 5 year overall survival rates, however, were similar in the TACE + RFA (93%, 72%, and 63%, respectively) and RFA (93%, 73%, and 53%, respectively) groups (P = 0.545), as were the rates of major complications (1.2% vs. 0.4%). Conclusions: Combined TACE and RFA was safe and provided better local tumor control than RFA alone in the treatment of 2- to 3-cm sized HCCs, although survival rates were similar.

Gamma Knife radiosurgery for large vestibular schwannomas greater than 3 cm in diameter.

Science.gov (United States)

Huang, Cheng-Wei; Tu, Hsien-Tang; Chuang, Chun-Yi; Chang, Cheng-Siu; Chou, Hsi-Hsien; Lee, Ming-Tsung; Huang, Chuan-Fu

2018-05-01

OBJECTIVE Stereotactic radiosurgery (SRS) is an important alternative management option for patients with small- and medium-sized vestibular schwannomas (VSs). Its use in the treatment of large tumors, however, is still being debated. The authors reviewed their recent experience to assess the potential role of SRS in larger-sized VSs. METHODS Between 2000 and 2014, 35 patients with large VSs, defined as having both a single dimension > 3 cm and a volume > 10 cm 3 , underwent Gamma Knife radiosurgery (GKRS). Nine patients (25.7%) had previously undergone resection. The median total volume covered in this group of patients was 14.8 cm 3 (range 10.3-24.5 cm 3 ). The median tumor margin dose was 11 Gy (range 10-12 Gy). RESULTS The median follow-up duration was 48 months (range 6-156 months). All 35 patients had regular MRI follow-up examinations. Twenty tumors (57.1%) had a volume reduction of greater than 50%, 5 (14.3%) had a volume reduction of 15%-50%, 5 (14.3%) were stable in size (volume change 3 cm and a volume > 10 cm 3 and tolerable mass effect can be managed satisfactorily with GKRS. Tumor volume ≥ 15 cm 3 is a significant factor predicting poor tumor control following GKRS.

Positive and negative streamers in ambient air: measuring diameter, velocity and dissipated energy

International Nuclear Information System (INIS)

Briels, T M P; Kos, J; Van Veldhuizen, E M; Ebert, U; Winands, G J J

2008-01-01

Positive and negative streamers are studied in ambient air at 1 bar; they emerge from a needle electrode placed 40 mm above a planar electrode. The amplitudes of the applied voltage pulses range from 5 to 96 kV; most pulses have rise times of 30 ns or shorter. Diameters, velocities and energies of the streamers are measured. Two regimes are identified; a low voltage regime where only positive streamers appear and a high voltage regime where both positive and negative streamers exist. Below 5 kV, no streamers emerge. In the range from 5 to 40 kV, positive streamers form, while the negative discharges only form a glowing cloud at the electrode tip, but no streamers. For 5-20 kV, diameters and velocities of the positive streamers have the minimal values of d = 0.2 mm and v ∼ 10 5 m s -1 . For 20-40 kV, their diameters increase by a factor of 6 while the voltage increases only by a factor of 2. Above the transition value of 40 kV, streamers of both polarities form; they strongly resemble each other, though the positive ones propagate further; their diameters continue to increase with applied voltage. For 96 kV, positive streamers attain diameters of 3 mm and velocities of 4 x 10 6 m s -1 ; negative streamers are about 20% slower and thinner. An empirical fit formula for the relation between velocity v and diameter d is v = 0.5d 2 mm -1 ns -1 for both polarities. Streamers of both polarities dissipate energies of the order of several millijoules per streamer while crossing the gap.

Spray cone angle and air core diameter of hollow cone swirl rocket injector

Directory of Open Access Journals (Sweden)

Ahmad Hussein Abdul Hamid

2011-12-01

Full Text Available ABSTRACT : Fuel injector for liquid rocket is a very critical component since that small difference in its design can dramatically affect the combustion efficiency. The primary function of the injector is to break the fuel up into very small droplets. The smaller droplets are necessary for fast quiet ignition and to establish a flame front close to the injector head, thus shorter combustion chamber is possible to be utilized. This paper presents an experimetal investigation of a mono-propellant hollow cone swirl injector. Several injectors with different configuration were investigated under cold flow test, where water is used as simulation fluid. This investigation reveals that higher injection pressure leads to higher spray cone angle. The effect of injection pressure on spray cone angle is more prominent for injector with least number of tangential ports. Furthermore, it was found that injector with the most number of tangential ports and with the smallest tangential port diameter produces the widest resulting spray. Experimental data also tells that the diameter of an air core that forms inside the swirl chamber is largest for the injector with smallest tangential port diameter and least number of tangential ports.ABSTRAK : Injektor bahan api bagi roket cecair merupakan satu komponen yang amat kritikal memandangkan perbezaan kecil dalam reka bentuknya akan secara langsung mempengaruhi kecekapan pembakaran. Fungsi utama injektor adalah untuk memecahkan bahan api kepada titisan yang amat kecil. Titisan kecil penting untuk pembakaran pantas secara senyap dan untuk mewujudkan satu nyalaan di hadapan, berhampiran dengan kepala injektor, maka kebuk pembakaran yang lebih pendek berkemungkinan dapat digunakan. Kertas kerja ini mebentangkan satu penyelidikan eksperimental sebuah injektor ekabahan dorong geronggang kon pusar. Beberapa injektor dengan konfigurasi berbeza telah dikaji di bawah ujian aliran sejuk, di mana air digunakan sebagai bendalir

Positive and negative streamers in ambient air: measuring diameter, velocity and dissipated energy

Energy Technology Data Exchange (ETDEWEB)

Briels, T M P; Kos, J; Van Veldhuizen, E M; Ebert, U [Department of Applied Physics, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands); Winands, G J J [Department of Electrical Engineering, Technische Universiteit Eindhoven, PO Box 513, 5600 MB Eindhoven (Netherlands)], E-mail: e.m.v.veldhuizen@tue.nl, E-mail: ebert@cwi.nl

2008-12-07

Positive and negative streamers are studied in ambient air at 1 bar; they emerge from a needle electrode placed 40 mm above a planar electrode. The amplitudes of the applied voltage pulses range from 5 to 96 kV; most pulses have rise times of 30 ns or shorter. Diameters, velocities and energies of the streamers are measured. Two regimes are identified; a low voltage regime where only positive streamers appear and a high voltage regime where both positive and negative streamers exist. Below 5 kV, no streamers emerge. In the range from 5 to 40 kV, positive streamers form, while the negative discharges only form a glowing cloud at the electrode tip, but no streamers. For 5-20 kV, diameters and velocities of the positive streamers have the minimal values of d = 0.2 mm and v {approx} 10{sup 5} m s{sup -1}. For 20-40 kV, their diameters increase by a factor of 6 while the voltage increases only by a factor of 2. Above the transition value of 40 kV, streamers of both polarities form; they strongly resemble each other, though the positive ones propagate further; their diameters continue to increase with applied voltage. For 96 kV, positive streamers attain diameters of 3 mm and velocities of 4 x 10{sup 6} m s{sup -1}; negative streamers are about 20% slower and thinner. An empirical fit formula for the relation between velocity v and diameter d is v = 0.5d{sup 2} mm{sup -1} ns{sup -1} for both polarities. Streamers of both polarities dissipate energies of the order of several millijoules per streamer while crossing the gap.

The image camera of the 17 m diameter air Cherenkov telescope MAGIC

CERN Document Server

Ostankov, A P

2001-01-01

The image camera of the 17 m diameter MAGIC telescope, an air Cherenkov telescope currently under construction to be installed at the Canary island La Palma, is described. The main goal of the experiment is to cover the unexplored energy window from approx 10 to approx 300 GeV in gamma-ray astrophysics. In its first phase with a classical PMT camera the MAGIC telescope is expected to reach an energy threshold of approx 30 GeV. The operational conditions, the special characteristics of the developed PMTs and their use with light concentrators, the fast signal transfer scheme using analog optical links, the trigger and DAQ organization as well as image reconstruction strategy are described. The different paths being explored towards future camera improvements, in particular the constraints in using silicon avalanche photodiodes and GaAsP hybrid photodetectors in air Cherenkov telescopes are discussed.

Retrograde intrarenal surgery versus percutaneous lithotripsy to treat renal stones 2-3 cm in diameter.

Science.gov (United States)

Zengin, Kursad; Tanik, Serhat; Karakoyunlu, Nihat; Sener, Nevzat Can; Albayrak, Sebahattin; Tuygun, Can; Bakirtas, Hasan; Imamoglu, M Abdurrahim; Gurdal, Mesut

2015-01-01

Retrograde intrarenal surgery (RIRS) performed using a flexible ureterorenoscope marked the beginning of a new era in urology. Today, even staghorn stones are successfully treated via RIRS. The recommended treatment for larger stones is percutaneous nephrolithotomy (PNL). However, the question of whether PNL or RIRS should be the first-line treatment option for larger stones remains controversial. In this study, we contribute to the debate by comparing the success and complication rates of PNL and RIRS that were used to treat renal pelvis stones 2-3 cm in diameter. The medical records of 154 patients (74 PNL, 80 RIRS) were retrospectively evaluated. PNL patients were placed in Group 1 and RIRS patients in Group 2. The complete stone-free rates were 95.5% in the PNL group and 80.6% in the RIRS group 1 month postoperatively (P = 0.061). The respective complication rates (evaluated using the Clavien system) were 13.5% and 8.8% (P = 0.520). RIRS affords a comparable success rate, causes fewer complications than PNL, and seems to be a promising alternative to PNL when larger stones are to be treated. Prospective randomized controlled trials are needed to confirm these findings.

Rapid monitoring of soil, smears, and air dusts by direct large-area alpha spectrometry

International Nuclear Information System (INIS)

Sill, C.W.

1992-01-01

Experimental conditions to permit rapid monitoring of soils, smears, and air dusts for transuranic (TRU) radionuclides under field conditions are described. The monitoring technique involves direct measurement of alpha emitters by alpha spectrometry using a large-area detector to identify and quantify the radionuclides present. The direct alpha spectrometry employs a circular gridded ionization chamber 35 cm in diameter which accommodates either a circular sample holder 25 cm in diameter or a rectangular one 20 by 25 cm (8 by 10 in.). Soils or settled dusts are finely ground, suspended in 30% ethanol, and sprayed onto a 25-cm stainless steel dish. Air dusts are collected with a high-volume sampler onto 20- by 25-cm membrane filters. Removable contamination is collected from surfaces onto a 20- by 25-cm filter using an 18-cm (7-in.) paint roller to hold the large filter in contact with the surface during sample collection. All three types of samples are then counted directly in the alpha spectrometer and no other sample preparation is necessary. Some results obtained are described

Measurement of the aortic diameter in the asymptomatic Korean population: Assessment with multidetector CT

International Nuclear Information System (INIS)

Lee, Sang Hwan; Lee, Whal; Choi, Hyuck Jae; Kim, Dae Jin; Park, Eun Ah; Chung, Jin Wook; Park, Jae Hyung

2013-01-01

To determine normal reference values for aortic diameters in asymptomatic Korean adults. Three hundred adults without signs or symptoms of cardiovascular diseases were enrolled in this study. Aortic diameters were measured at nine predetermined levels on CT images. Aortic diameter measurements were adjusted for body surface area. Analysis of data was performed with regard to age, sex, weight, height and hypertension. Aortic diameters were 2.99 ± 0.57 cm at the ascending aorta, 2.54 ± 0.35 cm at the transverse aortic arch, 2.36 ± 0.35 cm at the proximal descending thoracic aorta (DTA), 2.23 ± 0.37 cm at the mid DTA, 2.17 ± 0.38 cm at the distal DTA, 2.16 ± 0.37 cm at the thoracoabdominal junction, 2.10, 00B1, 0.35 cm at the level of the celiac axis, 1.94, 00B1, 0.36 cm at the suprarenal aorta, 1.58 ± 0.24 cm at the aortic bifurcation. Men had slightly larger diameters than women (p < 0.05). All diameters increased with age and hypertension, with statistical significance (p < 0.01). And all aortic diameters increased with height (p < 0.05) except at the level of the aortic arch (p = 0.056), and increased with weight (p < 0.05) except at the level of the suprarenal aorta (p = 0.067). Male sex, higher weight and height, age and hypertension are associated with larger aortic diameters in asymptomatic Korean adults.

Evaluation of neutronic characteristics of STACY 80-cm-diameter cylindrical core fueled with 6% enriched uranyl nitrate solution

International Nuclear Information System (INIS)

Yanagisawa, Hiroshi; Sono, Hiroki

2003-06-01

For the examination of neutronic safety design of forthcoming experimental core configurations in the Static Experiment Critical Facility (STACY), neutronic characteristics of 80-cm-diameter cylindrical cores fueled with 6% enriched uranyl nitrate solution have been evaluated by computational analyses. In the analyses, the latest nuclear data library, JENDL-3.3, was used as neutron cross section data. The neutron diffusion and transport calculations were performed using a diffusion code, CITATION, in the SRAC code system and a continuous-energy Monte Carlo code, MVP. Critical level heights of the cores were obtained using such parameters as uranium concentration (up to 500 gU/l), free nitric acid concentration (up to 8 mol/l), and concentration of soluble neutron poisons, gadolinium and boron. It has been confirmed from the evaluation that all critical cores comply with safety criteria required in the STACY operation concerning excess reactivity, reactivity addition rates and shutdown margins by safety rods. (author)

Model air-supported drum-type homopolar generator

International Nuclear Information System (INIS)

Kustom, R.L.; Fuja, R.E.; Wehrle, R.B.; Smith, R.P.; Kovarik, T.J.

1977-01-01

A single cylinder, drum-type homopolar generator has been designed and built for the purpose of developing a simple air support system for thin cylinder rotors operated at high surface velocities and significant radial drum growth. The model has an aluminum cylinder which is 0.32 cm thick, 25 cm in diameter, and 12.7 cm long. It is designed to operate at a peak current of 2500 A and to store a total of 40 kJ with a surface velocity of 305 m/sec

Simulation and spatiotemporal pattern of air temperature and precipitation in Eastern Central Asia using RegCM.

Science.gov (United States)

Meng, Xianyong; Long, Aihua; Wu, Yiping; Yin, Gang; Wang, Hao; Ji, Xiaonan

2018-02-26

Central Asia is a region that has a large land mass, yet meteorological stations in this area are relatively scarce. To address this data issues, in this study, we selected two reanalysis datasets (the ERA40 and NCEP/NCAR) and downscaled them to 40 × 40 km using RegCM. Then three gridded datasets (the CRU, APHRO, and WM) that were extrapolated from the observations of Central Asian meteorological stations to evaluate the performance of RegCM and analyze the spatiotemporal distribution of precipitation and air temperature. We found that since the 1960s, the air temperature in Xinjiang shows an increasing trend and the distribution of precipitation in the Tianshan area is quite complex. The precipitation is increasing in the south of the Tianshan Mountains (Southern Xinjiang, SX) and decreasing in the mountainous areas. The CRU and WM data indicate that precipitation in the north of the Tianshan Mountains (Northern Xinjiang, NX) is increasing, while the APHRO data show an opposite trend. The downscaled results from RegCM are generally consistent with the extrapolated gridded datasets in terms of the spatiotemporal patterns. We believe that our results can provide useful information in developing a regional climate model in Central Asia where meteorological stations are scarce.

Retrograde Intrarenal Surgery versus Percutaneous Lithotripsy to Treat Renal Stones 2-3 cm in Diameter

Directory of Open Access Journals (Sweden)

Kursad Zengin

2015-01-01

Full Text Available Objective. Retrograde intrarenal surgery (RIRS performed using a flexible ureterorenoscope marked the beginning of a new era in urology. Today, even staghorn stones are successfully treated via RIRS. The recommended treatment for larger stones is percutaneous nephrolithotomy (PNL. However, the question of whether PNL or RIRS should be the first-line treatment option for larger stones remains controversial. In this study, we contribute to the debate by comparing the success and complication rates of PNL and RIRS that were used to treat renal pelvis stones 2-3 cm in diameter. Materials and Methods. The medical records of 154 patients (74 PNL, 80 RIRS were retrospectively evaluated. PNL patients were placed in Group 1 and RIRS patients in Group 2. Results. The complete stone-free rates were 95.5% in the PNL group and 80.6% in the RIRS group 1 month postoperatively (P=0.061. The respective complication rates (evaluated using the Clavien system were 13.5% and 8.8% (P=0.520. Conclusions. RIRS affords a comparable success rate, causes fewer complications than PNL, and seems to be a promising alternative to PNL when larger stones are to be treated. Prospective randomized controlled trials are needed to confirm these findings.

Small Diameter Bomb Increment II (SDB II)

Science.gov (United States)

2015-12-01

Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-439 Small Diameter Bomb Increment II (SDB II) As of FY 2017 President’s Budget Defense... Bomb Increment II (SDB II) DoD Component Air Force Joint Participants Department of the Navy Responsible Office References SAR Baseline (Production...Mission and Description Small Diameter Bomb Increment II (SDB II) is a joint interest United States Air Force (USAF) and Department of the Navy

Axial variation of basic density of Araucaria angustifolia wood in different diameter classes

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Rômulo Trevisan

Full Text Available ABSTRACT: The study of the wood characteristics is of fundamental importance for the correct use of this raw material and, among its properties, the basic density is a major, being reference in the quality of this material. This study aimed to evaluate the axial variation of basic density of the wood of Araucaria angustifolia (Bertoloni O. Kuntze in different diameter classes. For this, three trees were selected in six diameter classes, called class 1 (20-30cm, class 2 (30.1-40cm, class 3 (40.1-50cm, class 4 (50.1-60cm, class 5 (60.1-70cm and class 6 (70.1-80cm. From each individual sampled was withdrawn a disc at 0.1m (base, 25, 50, 75 and 100% of the height of the first live branch and in the diameter at 1.30m from the ground (DBH, which were used for determining basic density. The weighted average basic density was equal to 0.422g cm-3 and, regardless of the diameter class analyzed, this property decreased in the axial direction. Diameter induced variation of basic density, but has not been verified a positive or negative systematic tendency in relation to the sampled interval.

Empirical equation to let reproducing the temperature field of air around a horizontal isothermal cylinder in natural convection case

International Nuclear Information System (INIS)

Diez Gonzalez, R.; Dolz, M.; Belsa, R.; Herraez, J.V.

1988-01-01

The analysis of 7.000 measured pairs of values, distance-temperature, of air around a horizontal isothermal cylinder has made possible to obtain an empirical simple equation to let reproducing the temperature field of air in the natural convection case. The experimental and calculated results for a cylinder of 1 cm diameter and 10.5 cm length are compared with the same given for other authors. (Author)

Fabrication of Two-Dimensional Arrays of Diameter-Tunable PS-b-P2VP Nanowires at the Air/Water Interface.

Science.gov (United States)

Zhao, Xingjuan; Yu, Xiaoli; Lee, Yong-Ill; Liu, Hong-Guo

2016-11-15

Composite thin films with well-defined and parallel nanowires were fabricated from the binary blends of a diblock copolymer polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) and several homopolystyrenes (h-PSs) at the air/liquid interface through a facile technique, which involves solution self-assembly, interface adsorption, and further self-organization processes. It was confirmed that the nanowires that appeared at the air/water interface came from the cylindrical micelles formed in solution. Interestingly, the diameters of the nanowires are uniform and can be tuned precisely from 45 to 247 nm by incorporating the h-PS molecules into the micellar core. This parallel alignment of the nanowires has potential applications in optical devices and enables the nanowires to be used as templates to prepare functional nanostructures. The extent to which h-PS molecules with different molecular weights are able to influence the diameter control of the nanowires was also systematically investigated.

Empirical equation to let reproducing the temperature field of air around a horizontal isothermal cylinder in natural convection case

Energy Technology Data Exchange (ETDEWEB)

Diez Gonzalez, R.; Dolz, M.; Belsa, R.; Herraez, J.V.

1988-01-01

The analysis of more or 7.000 measured pairs of values, diatance-temperature, of air around a horizontal isothermal cylinder has made it possible to obtain a empirical simple equation to let reproducing the temperature field of air in the natural convection case. The experimental and calculated results for a cylinder of 1 cm diameter and 10.5 cm length are compared with the same fiven for others authors

Tracheid diameter is the key trait determining the extent of freezing-induced embolism in conifers.

Science.gov (United States)

Pittermann, Jarmila; Sperry, John

2003-09-01

We tested the hypotheses that freezing-induced embolism is related to conduit diameter, and that conifers and angiosperms with conduits of equivalent diameter will exhibit similar losses of hydraulic conductivity in response to freezing. We surveyed the freeze-thaw response of conifers with a broad range of tracheid diameters by subjecting wood segments (root, stem and trunk wood) to a freeze-thaw cycle at -0.5 MPa in a centrifuge. Embolism increased as mean tracheid diameter exceeded 30 microm. Tracheids with a critical diameter greater than 43 microm were calculated to embolize in response to freezing and thawing at a xylem pressure of -0.5 MPa. To confirm that freezing-induced embolism is a function of conduit air content, we air-saturated stems of Abies lasiocarpa (Hook.) Nutt. (mean conduit diameter 13.7 +/- 0.7 microm) by pressurizing them 1 to 60 times above atmospheric pressure, prior to freezing and thawing. The air saturation method simulated the effect of increased tracheid size because the degree of super-saturation is proportional to a tracheid volume holding an equivalent amount of dissolved air at ambient pressure. Embolism increased when the dissolved air content was equivalent to a mean tracheid diameter of 30 microm at ambient air pressure. Our centrifuge and air-saturation data show that conifers are as vulnerable to freeze-thaw embolism as angiosperms with equal conduit diameter. We suggest that the hydraulic conductivity of conifer wood is maximized by increasing tracheid diameters in locations where freezing is rare. Conversely, the narrowing of tracheid diameters protects against freezing-induced embolism in cold climates.

Instrumentation development for an array of water Cherenkov detectors for extensive air shower experiments

Science.gov (United States)

Sheidaei, F.; Bahmanabadi, M.; Keivani, A.; Samimi, J.

2009-11-01

A new small array of Cherenkov detectors has been deployed in Tehran, 1200 m above sea level. This array contains four tanks of distilled water with a diameter of 64 cm and a height of 130 cm. The effective area of each tank is about 1382 cm2. They are used to detect air showers and to record the arrival time of the secondary particles. We have collected about 640 000 extensive air showers (EAS) in 8298 h of observation time from November 2006 to October 2007. The distribution of air showers in zenith and azimuth angles has been studied and a cosnθ distribution with n = 6.02 ± 0.01 was obtained for the zenith angle distribution. An asymmetry has been observed in the azimuthal distribution of EAS of cosmic rays due to geomagnetic field. The first and second amplitudes of the asymmetry are AI = 0.183 ± 0.001 and AII = 0.038 ± 0.001. Since the recent results are in good agreement with our previous results of scintillation detectors, and tanks of distilled water are cheaper, we prefer to use them instead of scintillators in a future larger array. By simulation, we have improved the size of the detectors to yield the highest efficiency. The best dimensions for each tank with a photomultiplier tube in the center of its lid are 40 cm in diameter and 60 cm in height.

Real-time precision measuring device of tree diameter growth

Science.gov (United States)

Guo, Mingming; Chen, Aijun; Li, Dongsheng; Liu, Nan; Yao, Jingyuan

2016-01-01

DBH(diameter at breast height) is an important factor to reflect of the quality of plant growth, also an important parameter indispensable in forest resources inventory and forest carbon sink, the accurate measurement of DBH or not is directly related to the research of forest resources inventory and forest carbon sink. In this paper, the principle and the mathematical model of DBH measurement device were introduced, the fixture measuring device and the hardware circuit for this tree diameter were designed, the measurement software programs were compiled, and the precision measuring device of tree diameter growth was developed. Some experiments with Australia fir were conducted. Based on experiment data, the correlations among the DBH variation of Australian fir, the environment temperature, air humility and PAR(photosynthetically active radiation) were obtained. The effects of environmental parameters (environment temperature, air humility and PAR) on tree diameter were analyzed. Experimental results show that there is a positive correlation between DBH variation of Australian fir and environment temperature, a negative correlation between DBH variation of Australian fir and air humility , so is PAR.

Pengaruh Diameter Partikel Terhadap Konsentrasi L-Dopa, Kc Dan De Pada Ekstraksi L-Dopa Dari Biji Kara Benguk (Mucuna Pruriens Dc.

Directory of Open Access Journals (Sweden)

Eni Budiyati

2013-10-01

Full Text Available Mucuna pruriens (biji kara benguk merupakan tanaman penghasil bahan obat-obatan karena mengandung senyawa L-Dopa. Senyawa tersebut dapat digunakan untuk pengobatan penyakit gangguan syaraf, anti bisa ular, meningkatkan bobot dan kekuatan otot, vitalitas seksual pria, zat anti-aging dan obat cacing pada manusia. Penelitian ini bertujuan untuk mengekstraksi L- Dopa dari biji kara benguk dengan menggunakan pelarut air. Di samping itu, penelitian ini juga mengevaluasi pengaruh dari diameter partikel terhadap konsentrasi L- dopa hasil ekstraksi, koefisien transfer massa (kC, dan difusivitas efektif (De. Tahapan yang digunakan pada penelitian ini adalah, persiapan bahan baku, proses ekstraksi, dan analisis L-Dopa. Proses ekstraksi dilakukan dalam tangki yang dilengkapi dengan thermometer. Analisis L-Dopa dilakukan dengan dengan High Performance Liquid Chromatography (HPLC. Hasil penelitian menunjukkan bahwa semakin kecil diameter partikel maka konsentrasi L-Dopa terekstrak semakin besar. Konsentrasi tertinggi diperoleh pada diameter partikel 0,5 mm yaitu 1739,56 ppm. Nilai difusivitas efektif (De untuk variabel diameter partikel (0,5; 0,675; 2,18; dan 2,5 mm hampir sama yaitu 2,99.10–5 sampai 3,07.10–5 cm2/menit. Sedangkan nilai koefisien transfer massa (kC berbanding terbalik dengan diameter partikel. Nilai kC berkisar antara 2,83.10-2 sampai 3,98.10-2 g/cm2.menit. 

A study on the various diameters of the heart and frontal cardiac area

International Nuclear Information System (INIS)

Kim, Byung Soo

1970-01-01

Cardiac measurement by radiographic method is the most accurate procedure by which physicians can obtain data regarding cardiac size in life. In order to determine the standard values among Koreans, cardiac mensuration by the radiographic frontal cardiac area method was carried out on 225 healthy Korean infants, 111 of whom were males and 114 were females. The results were as follows: 1. Transverse diameter at one month of age is 4.56 ± 0.12 cm in male and 5.00 ± 0.19 cm in female and at eleven months of age 7.35 ± 0.12 cm in male, 7.42 ± 0.09 cm in female. 2. Board diameter at one month of age is 3.94 ± 0.15 cm in male and 4.53 ± 0.19 cm in female and at eleven months of age 5.82 ± 0.14 cm in male, 5.94 ± 0.14 cm in female. 3. Long diameter at one month of age is 3.94 ± 0.15 cm in male and 5.30 ± 0.23 cm in female and at eleven months of age 7.67 ± 0.15 cm in male, 7.55 ± 0.11 cm in female. 4. The obliquity of the cardiac axis shows no significant difference in age and sex. The range of the measurements are between 31 .deg and 37 .deg. 5. Frontal cardiac area at one month of age is 14.36 ± 1.11 cm 2 in male and 18.97 ± 0.14 cm 2 in female and at eleven months of age 35.27 ± 1.21 cm 2 in male, 35.43 ± 0.45 cm 2 in female. 6. In every diameter and frontal cardiac area, except the obliquity of the cardiac axis, show greater value in female at the age of 1 month, but show almost same value in male as in female at the age of 11 months

Motion of air bubbles in stagnant water condition

International Nuclear Information System (INIS)

Bezdegumeli, U.; Ozdemir, S.; Yesin, O.

2004-01-01

In this study, air bubble motion in stagnant water condition in a vertical pipe of 4.6 cm diameter is investigated experimentally. For this purpose, a test set-up was designed and constructed. Motions of single bubbles, having different diameters in the range of 3.0-4.8 mm, were recorded by using a monochrome camera, an image capture card and a PC. Recorded video images were processed to analyse bubble motion and to obtain the necessary data. The purpose of the study is to determine the variation of bubble axial velocity and bubble drag coefficient as a function of equivalent bubble diameter and bubble Reynolds number, Re b . Therefore, detailed information for this range of bubble diameters was obtained. The results have shown good consistency with the previous studies found in the literature. (author)

Incidental, small (< 3 cm), unilocular, pancreatic cysts: Factors that predict lesion progression during imaging surveillance

Energy Technology Data Exchange (ETDEWEB)

Kim, Go Eun [Dept. of Radiology, Chonnam National University Hospital, Gwangju (Korea, Republic of); Shin, Sang Soo; Kim, Jin Woong; Heo, Suk Hee; Lim, Hyo Soon; Jun, Chung Hwan; Jeong, Yong Yeon [Chonnam National University Medical School, Gwangju (Korea, Republic of)

2017-11-15

To explore the features that predict size increase and development of potential malignant features in incidentally detected, unilocular cystic pancreatic lesions (CPLs) less than 3 cm in diameter, during subsequent follow-up. We retrieved data of patients diagnosed with unilocular CPLs less than 3 cm in diameter during the period from November 2003 through December 2014, using a computerized search. All serial CT and MR images were analyzed to identify the number, size, and location of CPLs; dilatation of the main pancreatic duct; and occurrence of worrisome features and high-risk stigmata of malignancy in the lesion. The characteristics of CPLs were compared between the increase (i.e., size increase during subsequent follow-up) and no-increase groups. For CPLs in the increase group, subgroup analysis was performed according to the lesion size at the last follow-up (< 3 cm vs. ≥ 3 cm). Among 553 eligible patients, 132 (23.9%) had CPLs that increased in size, and 421 (76.1%) had CPLs that did not, during follow-up. Of the 132, 12 (9.1%) CPLs increased to diameters ≥ 3 cm at the final follow-up. Among the various factors, follow-up duration was a significant independent factor for an interval size increase of CPLs (p < 0.001). In the increase group, initial cyst size was a significant independent factor to predict later size increase to or beyond 3 cm in diameter (p < 0.001), and the initial cyst diameter ≥ 1.5 cm predicted such a growth with a sensitivity and specificity of 83% and 72%, respectively. No significant factors to predict the development of potential malignant features were identified. Follow-up duration was associated with an interval size increase of CPLs. Among the growing CPLs, initial cyst size was associated with future lesion growth to and beyond 3 cm.

Automated estimation of abdominal effective diameter for body size normalization of CT dose.

Science.gov (United States)

Cheng, Phillip M

2013-06-01

Most CT dose data aggregation methods do not currently adjust dose values for patient size. This work proposes a simple heuristic for reliably computing an effective diameter of a patient from an abdominal CT image. Evaluation of this method on 106 patients scanned on Philips Brilliance 64 and Brilliance Big Bore scanners demonstrates close correspondence between computed and manually measured patient effective diameters, with a mean absolute error of 1.0 cm (error range +2.2 to -0.4 cm). This level of correspondence was also demonstrated for 60 patients on Siemens, General Electric, and Toshiba scanners. A calculated effective diameter in the middle slice of an abdominal CT study was found to be a close approximation of the mean calculated effective diameter for the study, with a mean absolute error of approximately 1.0 cm (error range +3.5 to -2.2 cm). Furthermore, the mean absolute error for an adjusted mean volume computed tomography dose index (CTDIvol) using a mid-study calculated effective diameter, versus a mean per-slice adjusted CTDIvol based on the calculated effective diameter of each slice, was 0.59 mGy (error range 1.64 to -3.12 mGy). These results are used to calculate approximate normalized dose length product values in an abdominal CT dose database of 12,506 studies.

On the air coolability of TRIGA reactors following a loss-of-coolant accident

International Nuclear Information System (INIS)

El-Genk, Mohamed S.; Kim, Sung-Ho; Zaki, Galal M.; Foushee, Fabian; Philbin, Jeffrey S.; Schulze, James

1986-01-01

This paper describes the experiments on the air-coolability of a heated rod in a vertical open annulus at near atmospheric pressure. This data can be applied to the coolability of reactor fuel rods that are totally uncovered in a Loss-of-Coolant Accident (LOCA). As a prelude to measuring air coolability of specific core geometries (bundles), heat transfer data was collected for natural convection of atmospheric air in open vertical annuli with an isoflux inner wall and an insulated outer wall (diameter ratios, annulus ratio, of 1.155, 1.33, 1.63, and 12). Although the inner heated tube had the same overall dimensions as the fuel rod in the Annular Core Research Reactor (ACRR) at Sandia National Laboratories (3.81 cm o.d. and 55.5 cm long), the heated length was only 36.0 cm rather than the entire 50.5 cm for the ACRR's rods. The test assembly was operated at heat fluxes up to 1.38 W/cm 2 with a corresponding surface temperature of 852 K. The annulus data was extrapolated to an equilibrium surface temperature of 1200 K (as a coolability limit of TRIGA reactors) to provide a qualitative estimate of the coolability of multirod bundles by free convection of atmospheric air. The results suggest that for a typical pitch-to-diameter ratio of 1.12 in the ACRR the decay heat removal level is about 1.0 kW/m. This corresponds to an initial decay power following sustained operations at about 12.5 kW/m in the ACRR. However, because of the uncertainties in duplicating the actual thermal-hydraulic conditions in a multirod bundle using a single rod annulus, the actual coolability of open pool reactors could be different from those suggested in this paper. (author)

Fabrication of large diameter alumino-silicate K+ sources

International Nuclear Information System (INIS)

Baca, D.; Chacon-Golcher, E.; Kwan, J.W.; Wu, J.K.

2003-01-01

Alumino-silicate K + sources have been used in HIF experiments for many years. For example the Neutralized Transport Expt. (NTX) and the High Current Transport Expt. (HCX) are now using this type of ion source with diameters of 2.54 cm and 10 cm respectively. These sources have demonstrated ion currents of 80 mA and 700 mA, for typical HIF pulse lengths of 5-10 (micro)s. The corresponding current density is ∼ 10-15 mA/cm 2 , but much higher current density has been observed using smaller size sources. Recently we have improved our fabrication techniques and, therefore, are able to reliably produce large diameter ion sources with high quality emitter surface without defects. This note provides a detailed description of the procedures employed in the fabrication process. The variables in the processing steps affecting surface quality, such as substrate porosity, powder size distribution, coating technique on large area concave surfaces, drying, and heat firing temperature have been investigated

SU-F-J-63: Abdominal Diameter Changes in Children During Volumetric Modulated Arc Therapy (VMAT): Is Re-Planning Needed?

Energy Technology Data Exchange (ETDEWEB)

Guerreiro, F; Janssens, G; Seravalli, E; Raaymakers, B [University Medical Center Utrecht, Department of Radiotherapy and Imaging Division, Utrecht (Netherlands)

2016-06-15

Purpose: To investigate the dosimetric impact of daily changes in patient’s diameter, due to weight gain/loss and air in the bowel, based on CBCT information during radiotherapy treatment of pediatric abdominal tumors. Methods: 10 pediatric patients with neuroblastoma (n=6) and Wilms’ (n=4) tumors were included. Available CBCTs were affinely registered to the planning CT for daily set-up variations corrections. A density override approach assigning air-density to the random air pockets and water-density to the remaining anatomy was used to determine the CBCT and CT dose. Clinical VMAT plans, with a PTV prescribed dose ranging between (14.4- 36) Gy, were re-optimized on the density override CT and re-calculated on each CBCT. Dose-volume statistics of the PTV and kidneys, delineated on each CBCT, were used to compare the daily and cumulative CBCT dose with the reference CT dose. Results: The average patient diameter variation was (0.5 ± 0.7) cm (maximum daily difference of 2.3 cm). The average PTV mean dose difference (MDD) between the CT and the cumulative CBCT plans was (0.1 ± 1.1) % (maximum daily MDD of 2%). A reduction in target coverage up to 3% and 7% was observed for the cumulative and daily CBCT plans, respectively. The average kidneys’ cumulative MDD was (−2.7 ± 3.6) % (maximum daily MDD of −12%), corresponding to an overdosage. Conclusion: Due to patient’s diameter changes, a target underdosage was assessed. Given the high local tumor control of neuroblastoma and Wilms’ diseases, the need of re-planning might be discarded. However, the assessed kidneys overdosage could represent a problem when the normal tissue tolerance is reached. The necessity of re-planning should then be considered to reduce the risk of long-term renal complications. Due to the poor softtissue contrast on CBCT, MRI-guidance is required to obtain a better assessment of the accumulated dose on the remaining OARs.

Exposure to Ultrafine Particles from Ambient Air and Oxidative Stress-Induced DNA Damage

DEFF Research Database (Denmark)

Bräuner, Elvira Vaclavik; Forchhammer, Lykke; Møller, Peter

2007-01-01

mononuclear cells (PBMCs) during controlled exposure to urban air particles with assignment of number concentration (NC) to four size modes with average diameters of 12, 23, 57, and 212 nm. DESIGN. Twenty-nine healthy adults participated in a randomized, two-factor cross-over study with or without biking...... exercise for 180 min and with exposure to particles (NC 6169-15362/cm3) or filtered air (NC 91-542/cm3) for 24 hr. METHODS: The levels of DNA strand breaks (SBs), oxidized purines as formamidopyrimidine DNA glycolase (FPG) sites, and activity of 7,8-dihydro-8-oxoguanine-DNA glycosylase (OGG1) in PBMCs were...

Hitungan Diameter Pipa pada Sistem Penyediaan Air Minum sederhana

Directory of Open Access Journals (Sweden)

Wahyu Widiyanto

2010-02-01

Full Text Available Drinking water sector is one of the public services which is connected tightly to poverty decrease. A small community water supply is more suitable if it uses a simple system which does not need sophisticated planning and construction. Nevertheless, hydraulics calculation should be always conducted accurately because it will influence water supply performance. In this case, pipe hydraulics needs more overview because system reliability depends on pipe capacity. This study discusses two methods of pipe diameter calculation at a simple drinking water supply system. For planning assistance, Directorate General Cipta Karya-Public Work Ministry issued Technical Guideline Book for Simple Drinking Water Construction in 2007. One of its chapters discusses about a method to find pipe diameter based on several tables available, but it is not given an explanation about basic theory of the tables so there is a doubt for planners. For the reason, comparison between the use of the tables (Juknis Method and Darcy-Weisbach Formula to calculate pipe diameter will be discussed. Data from 5 villages in Kebumen Regency will be utilized to support analysis. The result of procedure for making comparison shows that there is no significant difference (less than 4% between the result of calculation by Darcy-Weisbach Formula and Juknis Method with accurate interpolation. Both of the methods can be applied with its advantages and disadvantages. It is suggested that Darcy-Weisbach Formula is always implemented to re-check toward pipe diameter which is available in the market and will be used in the system.

Thirty-centimeter-diameter ion milling source

International Nuclear Information System (INIS)

Robinson, R.S.

1978-01-01

A 30 cm beam diameter ion source has been designed and fabricated for micromachining and sputtering applications. An argon ion current density of 1 mA/cm 2 at 500 eV ion energy was selected as a design operating condition. The completed ion source met the design criteria at this operating condition with a uniform and well-collimated beam having an average variation in current density of +- 5% over the center of 20 cm of the beam. This ion source has a multipole magnetic field that employs permanent magnets between permeable pole pieces. Langmuir probe surveys of the source plasma support the design concepts of a multipole field and a circumferential cathode to enhance plasma uniformity

Moisture monitoring in large diameter boreholes

International Nuclear Information System (INIS)

Tyler, S.

1985-01-01

The results of both laboratory and field experiments indicate that the neutron moisture gauge traditionally used in soil physics experiments can be extended for use in large diameter (up to 15 cm) steel-cased boreholes with excellent results. This application will permit existing saturated zone monitoring wells to be used for unsaturated zone monitoring of recharge, redistribution and leak detection from waste disposal facilities. Its applicability to large diameter cased wells also gives the soil physicist and ground-water hydrologist and new set of monitoring points in the unsaturated zone to study recharge and aquifer properties. 6 refs., 6 figs., 2 tabs

Assessing soil hydrological variability at the cm- to dm-scale using air permeameter measurements

Science.gov (United States)

Beerten, K.; Vandersmissen, N.; Rogiers, B.; Mallants, D.

2012-04-01

Soils and surficial sediments are crucial elements in the hydrological cycle since they are the medium through which infiltrating precipitation percolates to the aquifer. At the same time, soil horizons and shallow stratigraphy may act as hydraulic barriers that can promote runoff or interflow and hamper deep infiltration. For most catchments little is known about the small-scale horizontal and vertical variability of soil hydrological properties. Such information is however required to calculate detailed soil water flow paths and estimate small scale spatial variability in recharge and run-off. We present the results from field air permeameter measurements to assess the small-scale variability of saturated hydraulic conductivity in heterogeneous 2-D soil profiles. To this end, several outcrops in the unsaturated zone (sandy soils with podzolisation) of an interfluve in the Kleine Nete river catchment (Campine area, Northern Belgium) were investigated using a hand-held permeameter. Measurements were done each 10 cm on ~ 2 x 1 m or ~ 2 x 0.5 m grids. The initial results of the measurements (air permeability Kair; millidarcy) are recalculated to saturated hydraulic conductivity (Ks; m/s) using specific transfer functions (Loll et al., 1999; Iversen et al., 2003). Validation of the results is done with independent lab-based constant head Ks measurements. The results show that field based Ks values generally range between 10-3 m/s and 10-7 m/s within one profile, but extremely high values (up to 10-1 m/s) have been measured as well. The lowest values are found in the organic- and silt-rich Bh horizon of podzol soils observed within the profiles (~ 10-6-10-7m/s), while the highest values are observed in overlying dune sands less than 40 cm deep (up to 10-3 m/s with outliers to 10-1 m/s). Comparison of field and laboratory based Ks data reveals there is fair agreement between both methods, apart from several outliers. Scatter plots indicate that almost all points

Operation of a Five-Stage 40,000-CM2-Area Insulator Stack at 158 KV/CM

International Nuclear Information System (INIS)

Anderson RA; Clark, Robert E; Corcoran, PA; Douglas, John W; Gilliland, TL; Horry, ML; Hughes, Thomas P; Ives, HC; Long, FW; Martin, TH; McDaniel, DH; Milton, Osborne; Mostrom, Michael A; Seamen, JF; Shoup, RW; Smith, ID; Smith, JW; Spielman, RB; Struve, KW; Stygar, WA; Vogtlin, George E; Wagoner, TC; Yamamoto, Osamu

1999-01-01

We have demonstrated successful operation of a 3.35- m-diameter insulator stack at 158 kV/cm on five consecutive Z-accelerator shots. The stack consisted of five +45 deg;-profile 5.715-cm-thick cross-linked-polystyrene (Rexolite- 1422) insulator rings, and four anodized- aluminum grading rings shaped to reduce the field at cathode triple junctions. The width of the voltage pulse at 89% of peak was 32 ns. We compare this result to a new empirical flashover relation developed from previous small-insulator experiments conducted with flat unanodized electrodes. The relation predicts a 50% flashover probability for a Rexolite insulator during an applied voltage pulse when E max e -0.27/d (t eff C) 1/10 = 224, where E max is the peak mean electric field (kV/cm), d is the insulator thickness (cm), t eff is the effective pulse width (ps), and C is the insulator circumference (cm). We find the Z stack can be operated at a stress at least 19% higher than predicted. This result, and previous experiments conducted by Vogtlin, suggest anodized electrodes with geometries that reduce the field at both anode and cathode triple junctions would improve the flashover strength of +45 deg; insulators

Stress calculations for RTNS-iI 50-cm targets

International Nuclear Information System (INIS)

Schumacher, B.J.; House, P.A.

1981-04-01

Structural calculations made during design of a 50-cm target for the Rotating Target Neutron Source (RTNS-II) are detailed. The limited ability of the current 23-cm diameter target to dissipate the additional beam power required for a yield increase from 2 x 10 13 to 4 x 10 13 neutrons/second has resulted in the need for a larger target. The stresses of several design configurations for a 50-cm target were calculated. The stress contours that would occur in several different target designs with and without various types of structural reinforcement that reduce stress and deflection are presented

Measurements of stem diameter: implications for individual- and stand-level errors.

Science.gov (United States)

Paul, Keryn I; Larmour, John S; Roxburgh, Stephen H; England, Jacqueline R; Davies, Micah J; Luck, Hamish D

2017-08-01

Stem diameter is one of the most common measurements made to assess the growth of woody vegetation, and the commercial and environmental benefits that it provides (e.g. wood or biomass products, carbon sequestration, landscape remediation). Yet inconsistency in its measurement is a continuing source of error in estimates of stand-scale measures such as basal area, biomass, and volume. Here we assessed errors in stem diameter measurement through repeated measurements of individual trees and shrubs of varying size and form (i.e. single- and multi-stemmed) across a range of contrasting stands, from complex mixed-species plantings to commercial single-species plantations. We compared a standard diameter tape with a Stepped Diameter Gauge (SDG) for time efficiency and measurement error. Measurement errors in diameter were slightly (but significantly) influenced by size and form of the tree or shrub, and stem height at which the measurement was made. Compared to standard tape measurement, the mean systematic error with SDG measurement was only -0.17 cm, but varied between -0.10 and -0.52 cm. Similarly, random error was relatively large, with standard deviations (and percentage coefficients of variation) averaging only 0.36 cm (and 3.8%), but varying between 0.14 and 0.61 cm (and 1.9 and 7.1%). However, at the stand scale, sampling errors (i.e. how well individual trees or shrubs selected for measurement of diameter represented the true stand population in terms of the average and distribution of diameter) generally had at least a tenfold greater influence on random errors in basal area estimates than errors in diameter measurements. This supports the use of diameter measurement tools that have high efficiency, such as the SDG. Use of the SDG almost halved the time required for measurements compared to the diameter tape. Based on these findings, recommendations include the following: (i) use of a tape to maximise accuracy when developing allometric models, or when

On-line ultrasonic inside-diameter control system for Zircaloy

International Nuclear Information System (INIS)

Tanaka, Y.; Fujii, N.; Komatsu, M.; Kubota, H.

1984-01-01

An ultrasonic inside-diameter (ID) control system was used during the final etching process for producing Zircaloy nuclear fuel cladding tubes. This results in establishing automatic inside-diameter control during etching with an automatic etching system. In this system, the inside-diameter at the center point in the length of each tube is continuously measured with the ultrasonic inside-diameter measuring equipment during the etching process and the etching is automatically stopped by a signal from the control equipment when the inside-diameter reaches the target value. This made the final etching process economical and suitable for large-scale production, having an equal or better level at the inside-diameter of tubes etched with this system than those made by a process controlled by an air-micrometer

Calculation of conversion coefficients Hp(3)/K air using the PENELOPE Monte Carlo code and comparison with MCNP calculation results

International Nuclear Information System (INIS)

Daures, J.; Gouriou, J.; Bordy, J.M.

2010-01-01

The authors report calculations performed using the MNCP and PENELOPE codes to determine the Hp(3)/K air conversion coefficient which allows the Hp(3) dose equivalent to be determined from the measured value of the kerma in the air. They report the definition of the phantom, a 20 cm diameter and 20 cm high cylinder which is considered as representative of a head. Calculations are performed for an energy range corresponding to interventional radiology or cardiology (20 keV-110 keV). Results obtained with both codes are compared

Growth characteristics of mangrove seedling in silvofishery pond – the allometric relationship of height, diameter and leaf abundance

Science.gov (United States)

Dwi Hastuti, Endah; Budi Hastuti, Rini

2018-03-01

Dynamic environment condition of the silvofishery pond should provide an effect on the growth of mangrove seedling. This research aimed to observe the morphometric growth rate of mangrove seedling of Avicennia marina and Rhizophora mucronata planted in the silvofishery pond and to analyze the morphometric growth relationship of height, diameter and leaf number development of mangrove seedling. The research was conducted through field experiment involving mangrove species of A. marina and R. mucronata for 18 months during March 2015 to September 2016, both single structured and mixed structure. The observation was conducted every 13 weeks including seedling height, diameter and number of leaves. Data analysis was conducted by regression to provide the statistical relation between the growth of diameter – height, diameter – number of leaves and height – number of leaves. The result showed that the growth rate of A. marina in single structured pond was ranged from 0.38 – 3.00 cm.wk-1, 0.0015 – 0.0969 cm.wk‑1 and 0.1 – 13.7 leaves.wk‑1 respectively for height, diameter and number of leaves, while in mixed structure was 0.23 – 1.69 cm.wk‑1, 0.0169 – 0.0731 cm.wk‑1 and 0.5 – 14.0 leaves.wk-. The growth of R. mucronata respectively in single and mixed structure were 0.08 – 2.00 cm.wk‑1 and 0.15 – 2.62 cm.wk‑1, 0.0031 – 0.1369 cm.wk‑1 and 0.0008 – 0.0831 cm.wk‑1 and 0.0 – 1.9 leaves.wk‑1 and 0.0 – 1.6 leaves.wk-1respectively for height, diameter and number of leaves. Data analysis showed that the growth of seedling height of Avicennia in the mixed structure was significantly affected by its diameter growth and the number of leaves of Avicennia in single structured was significantly affected by its diameter. While the height, diameter and number of leaves of R. mucronata both in mixed and single structured silvofishery ponds were independent to each other. This research concluded that mangrove seedling growth is varied among

Los avances de la Metagenómica aplicados a la Microbiología del aire (Programa AIRBIOTA-CM)

OpenAIRE

Nuñez Hernández, Andrés; Rastrojo, Alberto; Garcia Ruiz, Ana Maria; Alcamí, Antonio; Gutiérrez-Bustillo, A. Montserrat; Campoy Cervera, Pascual; Guantes, Raúl; Moreno Gómez, Diego Alejandro

2015-01-01

El proyecto AIRBIOTA-CM nace del interés por conocer y modelizar en profundidad la biodiversidad del aire urbano. Los escasos estudios hasta el momento, a menudo parciales, centrados en un solo grupo taxonómico y abordado mediante técnicas tradicionales, sugieren que la diversidad de este ambiente es mayor de lo pensado, considerándolo como un ecosistema propio y con capacidad de interaccionar e influir sobre los demás presentes en la biosfera.

Absorption spectrum and absorption cross sections of the 2ν1 band of HO2 between 20 and 760 Torr air in the range 6636 and 6639 cm-1

Science.gov (United States)

Assaf, Emmanuel; Liu, Lu; Schoemaecker, Coralie; Fittschen, Christa

2018-05-01

The absorption spectrum of HO2 radicals has been measured in the range 6636-6639 cm-1 at several pressures between 20 and 760 Torr of air. Absolute absorption cross sections of the strongest line at around 6638.2 cm-1 have been determined from kinetic measurements, taking advantage of the well known rate constant of the self-reaction. Peak absorption cross sections of 22.6, 19.5, 14.4, 7.88, 5.12 and 3.23 × 10-20 cm2 were obtained at 20, 50, 100, 200, 400 and 760 Torr, respectively. By fitting these data, an empirical expression has been obtained for the absorption cross section of HO2 in the range 20-760 Torr air: σ6638.2cm-1 = 1.18 × 10-20 + (2.64 × 10-19 × (1-exp (-63.1/p (Torr))) cm2.

Air sampling program at the Portsmouth Gaseous Diffusion Plant

International Nuclear Information System (INIS)

Hulett, S.H.

1975-01-01

An extensive air sampling program has been developed at the Portsmouth Gaseous Diffusion Plant for monitoring the concentrations of radioactive aerosols present in the atmosphere on plantsite as well as in the environs. The program is designed to minimize exposures of employees and the environment to airborne radioactive particulates. Five different air sampling systems, utilizing either filtration or impaction, are employed for measuring airborne alpha and beta-gamma activity produced from 235 U and 234 Th, respectively. Two of the systems have particle selection capabilities: a personal sampler with a 10-mm nylon cyclone eliminates most particles larger than about 10 microns in diameter; and an Annular Kinetic Impactor collects particulates greater than 0.4 microns in diameter which have a density greater than 12-15 gm/cm 3 . A Hi-Volume Air Sampler and an Eberline Model AIM-3 Scintillation Air Monitor are used in collecting short-term samples for assessing compliance with ''ceiling'' standards or peak concentration limits. A film-sort aperture IBM card system is utilized for continuous 8-hour samples. This sampling program has proven to be both practical and effective for assuring accurate monitoring of the airborne activity associated with plant operations

SU-E-T-297: Dosimetric Assessment of An Air-Filled Balloon Applicator in HDR Vaginal Cuff Brachytherapy Using the Monte Carlo Method

International Nuclear Information System (INIS)

Jiang, H; Lee, Y; Pokhrel, D; Badkul, R

2015-01-01

Purpose: As an alternative to cylindrical applicators, air inflated balloon applicators have been introduced into HDR vaginal cuff brachytherapy treatment to achieve sufficient dose to vagina mucosa as well as to spare rectum and bladder. In general, TG43 formulae based treatment planning systems do not take into account tissue inhomogeneity, and air in the balloon applicator can cause higher delivered dose to mucosa than treatment plan reported. We investigated dosimetric effect of air in balloon applicator using the Monte Carlo method. Methods: The thirteen-catheter Capri applicator with a Nucletron Ir-192 seed was modeled for various balloon diameters (2cm to 3.5cm) using the MCNP Monte Carlo code. Ir-192 seed was placed in both central and peripheral catheters to replicate real patient situations. Existence of charged particle equilibrium (CPE) with air balloon was evaluated by comparing kerma and dose at various distances (1mm to 70mm) from surface of air-filled applicator. Also mucosa dose by an air-filled applicator was compared with by a water-filled applicator to evaluate dosimetry accuracy of planning system without tissue inhomogeneity correction. Results: Beyond 1mm from air/tissue interface, the difference between kerma and dose was within 2%. CPE (or transient CPE) condition was deemed existent, and in this region no electron transport was necessary in Monte Carlo simulations. At 1mm or less, the deviation of dose from kerma became more apparent. Increase of dose to mucosa depended on diameter of air balloon. The increment of dose to mucosa was 2.5% and 4.3% on average for 2cm and 3.5cm applicators, respectively. Conclusion: After introduction of air balloon applicator, CPE fails only at the proximity of air/tissue interface. Although dose to mucosa is increased, there is no significant dosimetric difference (<5%) between air and water filled applicators. Tissue inhomogeneity correction is not necessary for air-filled applicators

SU-E-T-297: Dosimetric Assessment of An Air-Filled Balloon Applicator in HDR Vaginal Cuff Brachytherapy Using the Monte Carlo Method

Energy Technology Data Exchange (ETDEWEB)

Jiang, H; Lee, Y; Pokhrel, D; Badkul, R [University of Kansas Hospital, Kansas City, KS (United States)

2015-06-15

Purpose: As an alternative to cylindrical applicators, air inflated balloon applicators have been introduced into HDR vaginal cuff brachytherapy treatment to achieve sufficient dose to vagina mucosa as well as to spare rectum and bladder. In general, TG43 formulae based treatment planning systems do not take into account tissue inhomogeneity, and air in the balloon applicator can cause higher delivered dose to mucosa than treatment plan reported. We investigated dosimetric effect of air in balloon applicator using the Monte Carlo method. Methods: The thirteen-catheter Capri applicator with a Nucletron Ir-192 seed was modeled for various balloon diameters (2cm to 3.5cm) using the MCNP Monte Carlo code. Ir-192 seed was placed in both central and peripheral catheters to replicate real patient situations. Existence of charged particle equilibrium (CPE) with air balloon was evaluated by comparing kerma and dose at various distances (1mm to 70mm) from surface of air-filled applicator. Also mucosa dose by an air-filled applicator was compared with by a water-filled applicator to evaluate dosimetry accuracy of planning system without tissue inhomogeneity correction. Results: Beyond 1mm from air/tissue interface, the difference between kerma and dose was within 2%. CPE (or transient CPE) condition was deemed existent, and in this region no electron transport was necessary in Monte Carlo simulations. At 1mm or less, the deviation of dose from kerma became more apparent. Increase of dose to mucosa depended on diameter of air balloon. The increment of dose to mucosa was 2.5% and 4.3% on average for 2cm and 3.5cm applicators, respectively. Conclusion: After introduction of air balloon applicator, CPE fails only at the proximity of air/tissue interface. Although dose to mucosa is increased, there is no significant dosimetric difference (<5%) between air and water filled applicators. Tissue inhomogeneity correction is not necessary for air-filled applicators.

Experimentally stabilized superconducting magnet with inner diameter of 700 mm

Energy Technology Data Exchange (ETDEWEB)

Vetlitskii, I A; Belonogov, A V; Dobrov, V M; Krylov, V L; Lebedev, A V; Lomkatsi, G S; Nilov, A F; Smolyankin, V T

1974-05-01

An experimental magnet, SPM-70, with the following characteristics was constructed. The inner diameter of the winding was 730 mm; outer diameter of the winding 1000 mm; height of winding 310 mm; magnetic induction at the center of the magnet 1.45 T; maximum magnetic induction 2.4 T; operation current 820 A; ampere-turns 1.07 x 10/sup 6/; design current density 2560 A/cm/sup 2/; stored energy 500 kJ; superconducting alloy Nb+50% Zr; weight of superconductor 23 kg; weight of copper 210 kg; resistivity of the copper in the strips at T = 4.2 K, B = 2.5 T, 2.6 x 10/sup -8/ ..cap omega.. cm.

Diameter measurements of polystyrene particles with atomic force microscopy

International Nuclear Information System (INIS)

Garnaes, J

2011-01-01

The size of (nano) particles is a key parameter used in controlling their function. The particle size is also important in order to understand their physical and chemical properties and regulate their number in health and safety issues. In this work, the geometric diameters of polystyrene spheres of nominal diameter 100 nm are measured using atomic force microscopy. The measurements are based on the apex height and on the average distance between neighbouring spheres when they form a close-packed monolayer on a flat mica substrate. The most important influence parameters for the determination of the geometric diameter are the lateral air gaps and deformation of the spheres. The lateral air gaps are caused by significant size variations of the individual spheres, and a correction is calculated based on the simulation of packing of spheres. The deformation of the spheres is caused mainly by capillary forces acting when they are in contact with each other or with the mica substrate. Based on calculated capillary forces and the literature values of the elastic properties of the polystyrene and mica, the deformation is estimated to be 2 nm with a standard uncertainty of 2 nm. The geometric diameter of the polystyrene spheres was measured with a combined standard uncertainty of ≈3 nm. The measured vertical diameter of 92.3 nm and the certified mobility equivalent diameter measured by differential mobility analysis (DMA) are marginally consistent at a confidence level of 95%. However, the measured lateral geometric diameter was 98.9 nm and is in good agreement with DMA

ANALISIS BEBAN KERJA OPERATOR MESIN PEMOTONG BATU BESAR (SIRKEL 160 CM DENGAN MENGGUNAKAN METODE 10 DENYUT

Directory of Open Access Journals (Sweden)

Andriyanto Andriyanto

2012-12-01

Full Text Available PT. PAH merupakan sebuah industri pemotongan batu magma (magma stone yang terletak di jalan Magelang Km. 15 Yogyakarta. Di perusahaan pemotongan batu ini terdapat 3 ukuran pemotongan yaitu sirkel besar (diameter 160 cm, sirkel sedang (diameter 60 - 90 cm dan sirkel kecil (diameter 30 - 50 cm. Penelitian ini khususnya pada pemotongan batu besar, dimana terdapat keluhan kelelahan operator yang terdiri dari operator utama dan operator pembantu. Penelitian dilakukan dengan tujuan untuk mengetahui tingkat beban kerja fisik operator pemotong batu besar (sirkel 160 dengan metode 10 denyut. Dalam penelitian ini ditentukan lama waktu istirahat yang dibutuhkan operator utama maupun pembantu. Selanjutnya dilakukan implementasi waktu istirahat tersebut dan dilakukan pengukuran kembali untuk mengetahui penurunan denyut nadi kerja operator. Penerapan waktu istirahat tersebut membawa penurunan DNK operator masuk kategori ringan dan % CVL masuk kategori tidak terjadi kelelahan.

Experiments on hydraulically-compensated Compressed Air Energy Storage (CAES) system using large-diameter vertical pipe two-phase flow test facility: test facility and test procedure

International Nuclear Information System (INIS)

Ohtsu, Iwao; Murata, Hideo; Kukita, Yutaka; Kumamaru, Hiroshige.

1996-07-01

JAERI, the University of Tokyo, the Central Research Institute of Electric Power Industry and Shimizu Corporation jointing performed and experimental study on two-phase flow in the hydraulically-compensated Compressed Air Energy Storage (CAES) system with a large-diameter vertical pipe two-phase flow test facility from 1993 to 1995. A hydraulically-compensated CAES system is a proposed, conceptual energy storage system where energy is stored in the form of compressed air in an underground cavern which is sealed by a deep (several hundred meters) water shaft. The shaft water head maintains a constant pressure in the cavern, of several mega Pascals, even during loading or unloading of the cavern with air. The dissolved air in the water, however, may create voids in the shaft when the water rises through the shaft during the loading, being forced by the air flow into the cavern. The voids may reduce the effective head of the shaft, and thus the seal may fail, if significant bubbling should occur in the shaft. This bubbling phenomenon (termed 'Champaign effect') and potential failure of the water seal ('blowout') are simulated in a scaled-height, scaled-diameter facility. Carbon dioxide is used to simulate high solubility of air in the full-height, full-pressure system. This report describes the expected and potential two-phase flow phenomena in a hydraulically-compensated CAES system, the test facility and the test procedure, a method to estimate quantities which are not directly measured by using measured quantities and hydrodynamic basic equations, and desirable additional instrumentation. (author)

Measured Performance of a Varied Airflow Small-Diameter Duct System

Energy Technology Data Exchange (ETDEWEB)

Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

2017-03-01

This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measure of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.

Measured Performance of a Varied Airflow Small-Diameter Duct System

Energy Technology Data Exchange (ETDEWEB)

Poerschke, Andrew [IBACOS, Inc., Pittsburgh, PA (United States)

2017-03-16

This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measure of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.

Properties of aerosol floating in the air in a nuclear power plant workplace environment

International Nuclear Information System (INIS)

Karasawa, H.; Funabashi, M.; Ito, M.

1992-01-01

An investigation was carried out on properties of radioactive aerosol floating in the air at several workplaces in nuclear power plant. The principal results are as follows: the aerosol particle size distributions consisted of two particle groups, whose aerodynamic diameters ranged from 4 to 7 microns and from 0.4 to 0.6 microns; the radioactive aerosol particle size distribution were unimodal. The mean activity median aerodynamic diameter (AMAD) was 6 microns, with geometric standard deviation microns; and, the average density of the aerosol was about 2.2g/cm 3 . (author)

The contribution to surface dose form air scatter in mega voltage photon beams

International Nuclear Information System (INIS)

Carolan, M.G.; Butson, M.; Metcalfe, P.

1996-01-01

Full text: The minimisation of surface dose is an important requirement in radiotherapy in order to avoid undesirable skin reactions. For this reason significant effort has been expended to avoid and understand photon and electron scatter in the heads of linear accelerators which may contribute to surface dose. In this study we have examined the contribution to surface dose which arises due to scatter in the air above the patient. Experimental investigations of air contributions are difficult to design and execute. Therefore we have used Monte Carlo calculations to determine the effect that the presence of air has on surface dose. Methods: The Los Alamos Monte Carlo Neutron and Photon transport code, MCNP4A which incorporates the ETRAN electron transport code from the Integrated TIGER Series of codes was used for our simulations. The geometry used in the model was a 30 cm cube of water. The dose was tallied in cylindrical elements of 7 cm diameter along the axis of the photon beam. For the first millimetre along the beam axis in the phantom, the dose was determined at 0.1 mm increments in 0.1 mm thick volumes. For depths between 1.0 mm and 15.0 mm the dose was determined every 1 mm in 1 mm cylindrical volumes. This yields a depth dose profile with fine spatial resolution near the phantom surface. Dose was also tallied at depths of 5.0, 10.0, 15.0 and 20.0 cm. The simulations were done assuming a 6 MV photon source with a diameter of 1.5 cm, a gaussian intensity profile and a photon energy spectrum based on Mohan et al. (Med. Phys. 12 (1985) 592). No accelerator head geometry was modelled. The field size was defined by virtual collimators which were simply thin regions of zero photon importance and therefore do not contribute to photon or electron scatter. All simulations were run for sufficient particle histories (∼2x10 7 - 5x10 7 source photons) to give statistical uncertainties of ≤ 10% and in most cases ≤ 5%. Fields of size 10, 15, 20 and 25 cm were used

Positive streamers in air and nitrogen of varying density: experiments on similarity laws

International Nuclear Information System (INIS)

Briels, T M P; Van Veldhuizen, E M; Ebert, U

2008-01-01

Positive streamers in ambient air at pressures from 0.013 to 1 bar are investigated experimentally. The voltage applied to the anode needle ranges from 5 to 45 kV, the discharge gap from 1 to 16 cm. Using a 'slow' voltage rise time of 100-180 ns, the streamers are intentionally kept thin. For each pressure p, we find a minimal diameter d min . To test whether streamers at different pressures are similar, the minimal streamer diameter d min is multiplied by its pressure p; we find this product to be well approximated by p · d min = 0.20 ± 0.02 mm bar over two decades of air pressure at room temperature. The value also fits diameters of sprite discharges above thunderclouds at an altitude of 80 km when extrapolated to room temperature (as air density rather than pressure determines the physical behaviour). The minimal velocity of streamers in our measurements is approximately 0.1 mm ns -1 = 10 5 m s -1 . The same minimal velocity has been reported for tendrils in sprites. We also investigate the size of the initial ionization cloud at the electrode tip from which the streamers emerge, and the streamer length between branching events. The same quantities are also measured in nitrogen with a purity of approximately 99.9%. We characterize the essential differences with streamers in air and find a minimal diameter of p · d min = 0.12 ± 0.02 mm bar in our nitrogen.

High-temperature hydrogen-air-steam detonation experiments in the BNL small-scale development apparatus

International Nuclear Information System (INIS)

Ciccarelli, G.; Ginsburg, T.; Boccio, J.; Economos, C.; Finfrock, C.; Gerlach, L.; Sato, K.; Kinoshita, M.

1994-08-01

The Small-Scale Development Apparatus (SSDA) was constructed to provide a preliminary set of experimental data to characterize the effect of temperature on the ability of hydrogen-air-steam mixtures to undergo detonations and, equally important, to support design of the larger scale High-Temperature Combustion Facility (HTCF) by providing a test bed for solution of a number of high-temperature design and operational problems. The SSDA, the central element of which is a 10-cm inside diameter, 6.1-m long tubular test vessel designed to permit detonation experiments at temperatures up to 700K, was employed to study self-sustained detonations in gaseous mixtures of hydrogen, air, and steam at temperatures between 300K and 650K at a fixed initial pressure of 0.1 MPa. Hydrogen-air mixtures with hydrogen composition from 9 to 60 percent by volume and steam fractions up to 35 percent by volume were studied for stoichiometric hydrogen-air-steam mixtures. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air gas mixture temperature, in the range 300K-650K, is to decrease cell size and, hence, to increase the sensitivity of the mixture to undergo detonations. The effect of steam content, at any given temperature, is to increase the cell size and, thereby, to decrease the sensitivity of stoichiometric hydrogen-air mixtures. The hydrogen-air detonability limits for the 10-cm inside diameter SSDA test vessel, based upon the onset of single-head spin, decreased from 15 percent hydrogen at 300K down to between 9 and 10 percent hydrogen at 650K. The one-dimensional ZND model does a very good job at predicting the overall trends in the cell size data over the range of hydrogen-air-steam mixture compositions and temperature studied in the experiments

Detonation cell size measurements and predictions in hydrogen-air-steam mixtures at elevated temperatures

International Nuclear Information System (INIS)

Ciccarelli, G.; Ginsberg, T.; Boccio, J.; Economos, C.

1994-01-01

The present research reports on the effect of initial mixture temperature on the experimentally measured detonation cell size for hydrogen-air-steam mixtures. Experimental and theoretical research related to combustion phenomena in hydrogen-air-steam mixtures has been ongoing for many years. However, detonation cell size data currently exists or hydrogen-air-steam mixtures up to a temperature of only 400K. Sever accident scenarios have been identified for light water reactors (LWRs) where hydrogen-air mixture temperatures in excess of 400K could be generated within containment. The experiments in this report focus on extending the cell size data base for initial mixture temperatures in excess of 400K. The experiments were carried out in a 10-cm inner-diameter, 6.1-m long heated detonation tube with a maximum operating temperature of 700K and spatial temperature uniformity of ±14K. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air initial gas mixture temperature, in the range 300K--650K, is to decrease cell size and, hence, to increase the sensitivity of the mixture to undergo detonations. The effect of steam content, at any given temperature, is to increase the cell size and, thereby, to decrease the sensitivity of stoichiometric hydrogen-air mixtures. The hydrogen-air detonability limits for the 10-cm inside-diameter test vessel, based upon the onset of single-head spin, decreased from 15 percent by hydrogen at 300K down to about 9 percent hydrogen at 650K. The one-dimensional ZND model does a very good job at predicting the overall trends in the cell size data over the range of hydrogen-air-steam mixture compositions and temperature studied in the experiments

Failure Diameter of PBX 9502: Simulations with the SURFplus model

Energy Technology Data Exchange (ETDEWEB)

Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-07-03

SURFplus is a reactive burn model for high explosives aimed at modelling shock initiation and propagation of detonation waves. It utilizes the SURF model for the fast hot-spot reaction plus a slow reaction for the energy released by carbon clustering. A feature of the SURF model is that there is a partially decoupling between burn rate parameters and detonation wave properties. Previously, parameters for PBX 9502 that control shock ini- tiation had been calibrated to Pop plot data (distance-of-run to detonation as a function of shock pressure initiating the detonation). Here burn rate parameters for the high pres- sure regime are adjusted to t the failure diameter and the limiting detonation speed just above the failure diameter. Simulated results are shown for an uncon ned rate stick when the 9502 diameter is slightly above and slightly below the failure diameter. Just above the failure diameter, in the rest frame of the detonation wave, the front is sonic at the PBX/air interface. As a consequence, the lead shock in the neighborhood of the interface is supported by the detonation pressure in the interior of the explosive rather than the reaction immediately behind the front. In the interior, the sonic point occurs near the end of the fast hot-spot reaction. Consequently, the slow carbon clustering reaction can not a ect the failure diameter. Below the failure diameter, the radial extent of the detonation front decreases starting from the PBX/air interface. That is, the failure starts at the PBX boundary and propagates inward to the axis of the rate stick.

Studi Eksperimen Pengaruh Dimensi Pipa Kapiler Pada Sistem Air Conditioning Dengan Pre-Cooling

Directory of Open Access Journals (Sweden)

Awan Satya Darmawan

2017-01-01

Full Text Available Penggunaan air conditioner semakin banyak digunakan pada kehidupan sehari-hari diiringi dengan harga jual energi yang semakin mahal. Pada studi eksperimen kali ini mencoba mengoptimalisasi dan menigkatkan efisiensi energi pada sistem air conditioner dengan cara menambahkan satu buah evaporator dan satu buah pre-cooling, dimana pre-cooling dimanfaatkan untuk memanaskan air yang nantinya akan digunakan untuk keperluan rumah tangga. Pada sistem pengkondisian udara yang telah dimodifikasi tersebut maka dilakukan studi eksperimen dengan variasi panjang pipa kapiler, diameter pipa kapiler d=0,054 in, dengan panjang kapiler 1 = 35 cm, kapiler 2 = 65 cm, kapiler 3 = 95 cm. Hasil yang didapat dari studi eksperimen kali ini adalah semakin bertambahnya panjang pipa kapiler, kapasitas pendinginan evaporator, kerja kompresor dan COP dari sistem juga akan semakin kecil dan juga mengakibatkan temperatur masuk evaporator akan semakin kecil, yang akan mengakibatkan efek pendinginan akan semakin besar. Pada variasi pipa kapiler terpendek 35 cm menghasilkan data kapasitas pendinginan total sebesar 2,25 kW, kerja kompresor 0,433 kW, temperatur masuk evaporator 7,26°C, COP sebesar 5,21 dan HRR sebesar 1,16. Sedangkan pada variasi pipa kapiler terpanjang 95 cm kapasitas pendinginan total sebesar 0,72 kW, kerja kompresor 0,332 kW, temperatur masuk evaporator 1,64°C, COP sebesar 4,35 dan HRR sebesar 1,26.

Determination of vanillin in vanilla perfumes and air by capillary electrophoresis.

Science.gov (United States)

Minematsu, Saaya; Xuan, Guang-Shan; Wu, Xing-Zheng

2013-12-01

The present study investigated capillary electrophoretic detection of vanillin in vanilla perfume and air. An UV-absorbance detector was used in a home-made capillary electrophoretic instrument. A fused silica capillary (outer diameter: 364 μm, inner diameter: 50 μm) was used as a separation capillary, and a high electric voltage (20 kV) was applied across the two ends of the capillary. Total length of the capillary was 70 cm, and the effective length was 55 cm. Experimental results showed that the vanillin peak was detected at about 600, 450, and 500 seconds when pH of running buffers in CE were 7.2, 9.3, and 11.5, respectively. The peak area of vanillin was proportional to its concentration in the range of 0-10(-2) mol/L. The detection limit was about 10(-5) mol/L. Vanillin concentration in a 1% vanilla perfume sample was determined to be about 3×10(-4) mol/L, agreed well with that obtained by a HPLC method. Furthermore, determination of vanillin in air by combination of CE and active carbon adsorption method was investigated. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

[First time revealed small formations of lungs (under 2 cm in diameter). Dynamic follow-up or surgery?

Science.gov (United States)

Pavlov, Yu V; Rybin, V K

To develop the treatment algorithm in patients with first time revealed lung lesions smaller than 2 cm. The study included 110 patients with pathological lung lesions with small dimensions who have been treated in the Burdenko Clinic of Faculty Surgery for the period 1997-2013. All patients underwent surgical removal of lung tissue using different surgical approaches: 44 cases of videothoracoscopic resections, 43 video-assisted minithoracotomies, 23 minithoracotomies. There were 25 patients with lung cancer, 38 cases of benign tumours (hamartoma and tuberculoma) and 10 patients with disseminated tuberculosis thar required special treatment. Small pulmonary formations (from 0.5 to 2 cm) can be removed without morphological verification prior to surgery. Optimal surgical approach should be selected depending on the amount and size of formations. Management of solitary lung formation smaller than 0.5 cm that was newly diagnosed by computed tomography should include dynamic follow-up and performance of computed tomography in 3-6-12 months.

Effects of Specimen Diameters on the Distribution of Corrosion Fatigue Cracks

OpenAIRE

石原, 外美; 塩澤, 和章; 宮尾, 嘉寿

1988-01-01

The distribution of corrosion fatigue cracks observed on the un-notched round specimen surface differs with specimen diameter, especially in the low stress amplitude region. At a constant fatigue life ratio, many long cracks are initiated on the larger specimen, 12 mm (diameter), in comparison with the smaller specimen, 6 mm (diameter). On the other hand, in the high stress amplitude region of corrosion fatigue and fatigue in laboratory air, the distribution of cracks during the fatigue proce...

EFISIENSI CONSTRUCTION WETLAND TYPHA SP. SEBAGAI PENGOLAH AIR LIMPASAN JALAN RAYA SECARA ALAMI

Directory of Open Access Journals (Sweden)

Rudatin Windraswara

2011-02-01

Full Text Available Penelitian ini bersifat desain eksperimental pada skala laboratorium untuk mengetahui kemampuan Typha latifolia. sebagai tanaman wetland dalam mereduksi BOD dan COD yang berasal polutan air limpasan jalan raya sebagai bagian dari sistem drainase yang berkelanjutan. Sampel dalam penelitian ini adalah air limpasan jalan yang berasal dari air hujan yang kemudian masuk ke saluran pengumpul (drainase jalan. Habitat wetland disimulasikan menggunakan kolom dengan tabung yang memiliki volume kosong 20 liter. Susunan tabung adalah sebagai berikut; tanaman wetland, air, pasir dan batu kerikil. Satu tabung lagi akan berlaku sebagai kontrol dengan susunan yang sama tanpa tanaman wetland. Desain tabung memiliki spesifikasi sebagai berikut bahan acrylic dengan ukuran diameter 9,7 cm, tinggi 40 cm, volume 20 liter, media pasir setinggi 10 cm, kerikil 15 cm, kemudian diisi air setinggi 15 cm dari batas kerikil. Nilai BOD dari sampel kontrol setelah hari ke-3 menjadi 87 mg/l dari nilai semula 104 mg/l sedangkan nilai BOD dari sampel uji setelah hari ke-3 menjadi 44 mg/l dari nilai semula 104 mg/l. Hasil ini menunjukkan tanaman tersebut mampu menghilangkan nilai BOD sebesar 65% atau BOD removal sebesar 65%. Nilai COD dari sampel kontrol setelah hari ke-3 menjadi 309 mg/l dari nilai semula 210 mg/l sedangkan nilai COD dari sampel uji setelah hari ke-3 menjadi 87 mg/l dari nilai semula 210 mg/l. Hasil ini menunjukkan tanaman Typha latifolia mampu menghilangkan nilai COD sebesar 58,6% atau COD removal sebesar 58,6%. Kedua parameter tersebut telah sesuai dengan baku mutu Kepmen LH no 112 tahun 2003 dan Kepmen LH no 51 tahun 1999.

A tape-controlled remote automatic diameter measurement machine

International Nuclear Information System (INIS)

Jennison, W.; Salmon, A.M.

1978-01-01

The machine is designed for the automatic measurement of fuel pins after irradiation in the fast reactors and is a modified version of a machine which has been in use for several years. These modifications consist of mechanical improvements and solid state control circuitry but the design criteria are unchanged. Irradiated fuel pins with diameters up to 0.875 in. are measured at fixed axial positions and angular intervals. Axial stepping of either 1 cm or 1 in. with a standard deviation of 5 x 10 -4 in. and angular rotation by multiples of 18 0 with a non-cumulative error of 1 0 can be selected. Data on axial position to 0.1 in. or 0.1 cm and fuel element diameter to 5 x 10 -5 in. are both punched and printed out for computer evaluation. The standard deviation of a single measurement on cylindrical specimens with an eccentricity of up to at least 0.1 in. should be no worse than 1 x 10 -4 in. No operator attention is required after the pin is positioned in the machine and 40 sets of 10 diameter readings at 36 0 intervals can be performed in an hour. Switches can be set between 1 and 99 to terminate an examination when power is switched off with the machine in its rest position. (author)

Measurement of the factor of dispersion in air for a field of 0,8* 8,0 CM 2

International Nuclear Information System (INIS)

Gomez-Tejedor Alonso, S.; Huertas Martinez, C.; Penedo Cobos, J. M.; Garcia Castejon, M. A.; Rincon Perezx, M.

2013-01-01

The measures of this factor of dispersion in air is usually performed with an ionization chamber cover a cap of balance of such thickness that is achieved the electronic balance, and must be covered completely the CAP by the radiation field. This procedure is not applicable for small fields. The need to measure the Sc of a field of 0.8 * 0.8 cm 2 for a new system of planning led us to try another measure procedure proposed in the literature, using detectors of semiconductor with a sheet of cerrobend by way of balance Cap. (Author)

Positive streamers in air and nitrogen of varying density: experiments on similarity laws

Energy Technology Data Exchange (ETDEWEB)

Briels, T M P; Van Veldhuizen, E M; Ebert, U [Department of Applied Physics, Technische Universiteit Eindhoven, P O Box 513, 5600 MB Eindhoven (Netherlands)], E-mail: ebert@cwi.nl, E-mail: e.m.v.veldhuizen@tue.nl

2008-12-07

Positive streamers in ambient air at pressures from 0.013 to 1 bar are investigated experimentally. The voltage applied to the anode needle ranges from 5 to 45 kV, the discharge gap from 1 to 16 cm. Using a 'slow' voltage rise time of 100-180 ns, the streamers are intentionally kept thin. For each pressure p, we find a minimal diameter d{sub min}. To test whether streamers at different pressures are similar, the minimal streamer diameter d{sub min} is multiplied by its pressure p; we find this product to be well approximated by p {center_dot} d{sub min} = 0.20 {+-} 0.02 mm bar over two decades of air pressure at room temperature. The value also fits diameters of sprite discharges above thunderclouds at an altitude of 80 km when extrapolated to room temperature (as air density rather than pressure determines the physical behaviour). The minimal velocity of streamers in our measurements is approximately 0.1 mm ns{sup -1} = 10{sup 5} m s{sup -1}. The same minimal velocity has been reported for tendrils in sprites. We also investigate the size of the initial ionization cloud at the electrode tip from which the streamers emerge, and the streamer length between branching events. The same quantities are also measured in nitrogen with a purity of approximately 99.9%. We characterize the essential differences with streamers in air and find a minimal diameter of p {center_dot} d{sub min} = 0.12 {+-} 0.02 mm bar in our nitrogen.

Influence of bronchial diameter change on the airflow dynamics based on a pressure-controlled ventilation system.

Science.gov (United States)

Ren, Shuai; Cai, Maolin; Shi, Yan; Xu, Weiqing; Zhang, Xiaohua Douglas

2018-03-01

Bronchial diameter is a key parameter that affects the respiratory treatment of mechanically ventilated patients. In this paper, to reveal the influence of bronchial diameter on the airflow dynamics of pressure-controlled mechanically ventilated patients, a new respiratory system model is presented that combines multigeneration airways with lungs. Furthermore, experiments and simulation studies to verify the model are performed. Finally, through the simulation study, it can be determined that in airway generations 2 to 7, when the diameter is reduced to half of the original value, the maximum air pressure (maximum air pressure in lungs) decreases by nearly 16%, the maximum flow decreases by nearly 30%, and the total airway pressure loss (sum of each generation pressure drop) is more than 5 times the original value. Moreover, in airway generations 8 to 16, with increasing diameter, the maximum air pressure, maximum flow, and total airway pressure loss remain almost constant. When the diameter is reduced to half of the original value, the maximum air pressure decreases by 3%, the maximum flow decreases by nearly 5%, and the total airway pressure loss increases by 200%. The study creates a foundation for improvement in respiratory disease diagnosis and treatment. Copyright © 2017 John Wiley & Sons, Ltd.

Propagação de Jabuticabeira por enxertia e alporquia Propagation of jabuticaba tree for grafting and air layering techniques

Directory of Open Access Journals (Sweden)

Simone Aparecida Zolet Sasso

2010-06-01

Full Text Available O objetivo deste trabalho foi investigar a eficiência das técnicas de enxertia e alporquia na produção de mudas de jabuticabeira. Testou-se a pega de enxertia de três espécies de jabuticabeira (Plinia cauliflora, P. trunciflora, P. jaboticaba sobre porta-enxertos de P. cauliflora, em duas épocas (maio e agosto. Avaliaram-se a brotação e o número e tamanho de brotos, após 90 dias da implantação do experimento. Para alporquia, foram testados dois diâmetros de ramos (1,0-1,5 cm e 2,0-2,5 cm e duas larguras do anelamento (1,5 cm e 3,0 cm, na espécie P. cauliflora. Avaliaram-se o enraizamento e o número e tamanho de raízes, após 180 dias da implantação do experimento. A enxertia e a alporquia são técnicas recomendáveis para a propagação da jabuticabeira, pois proporcionam alto percentual de formação de mudas, de até 72,9% e 87,5%, respectivamente. Houve pega de enxertia das três espécies enxertadas sobre P. cauliflora. A utilização de garfos retirados de plantas em frutificação deve ser evitada, pois ocorre inibição da brotação dos enxertos. Na alporquia, ramos de diâmetro de 2,0-2,5 cm proporcionam maior enraizamento e maior número e tamanho de raízes, em relação a ramos de menor diâmetro (1,0 a 1,5 cm.The objective of this work was to test the efficiency of grafting and air layering propagation techniques for jabuticaba tree. Was tested compatibility of grafting of three species of jabuticaba tree (Plinia cauliflora, P. trunciflora and P. jaboticaba on rootstocks of P. cauliflora, and two periods (May and August. The percentage of grafting, number and size of shoots, was evaluated 90 days after the experiment started. Air layering was made in P. cauliflora using two diameters of branches (1.0-1.5 cm and 2.0-2.5 cm and two widths of girdling (1.5 cm and 3.0 cm. It was evaluated the rooting percentage, number and length of roots, 180 days after the experiment started. Both grafting and the air layering are

Ecological Importance of Large-Diameter Trees in a Temperate Mixed-Conifer Forest

Science.gov (United States)

Lutz, James A.; Larson, Andrew J.; Swanson, Mark E.; Freund, James A.

2012-01-01

Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. Although both scaling theory and competition theory make predictions about the relative composition and spatial patterns of large-diameter trees compared to smaller diameter trees, these predictions are rarely tested. We established a 25.6 ha permanent plot within which we tagged and mapped all trees ≥1 cm dbh, all snags ≥10 cm dbh, and all shrub patches ≥2 m2. We sampled downed woody debris, litter, and duff with line intercept transects. Aboveground live biomass of the 23 woody species was 507.9 Mg/ha, of which 503.8 Mg/ha was trees (SD = 114.3 Mg/ha) and 4.1 Mg/ha was shrubs. Aboveground live and dead biomass was 652.0 Mg/ha. Large-diameter trees comprised 1.4% of individuals but 49.4% of biomass, with biomass dominated by Abies concolor and Pinus lambertiana (93.0% of tree biomass). The large-diameter component dominated the biomass of snags (59.5%) and contributed significantly to that of woody debris (36.6%). Traditional scaling theory was not a good model for either the relationship between tree radii and tree abundance or tree biomass. Spatial patterning of large-diameter trees of the three most abundant species differed from that of small-diameter conspecifics. For A. concolor and P. lambertiana, as well as all trees pooled, large-diameter and small-diameter trees were spatially segregated through inter-tree distances trees and spatial relationships between large-diameter and small-diameter trees. Long-term observations may reveal regulation of forest biomass and spatial structure by fire, wind, pathogens, and insects in Sierra Nevada mixed-conifer forests. Sustaining ecosystem functions such as carbon storage or provision of specialist species habitat will likely require different management strategies when the functions are performed primarily by a few large trees as opposed to many smaller trees. PMID:22567132

Scaling law in free walking of mice in circular open fields of various diameters.

Science.gov (United States)

Shoji, Hiroto

2016-03-01

Open-field tests are routinely used to study locomotor activity in rodents. I studied the effects of apparatus size on rodent locomotor activity, specifically with respect to how resting and walking periods are interwoven. I explored the open-field behavior of mice utilizing circular open fields of various diameters. When the diameter of the test apparatus was greater than 75 cm, the durations of the resting and moving periods of free walking behavior obeyed bounded power-law distribution functions. I found that the properties of the scaling exponents and model selection became similar for test apparatus diameters greater than 75 cm. These results can provide a guide for the selection of the size of the test apparatus for use in the study of the open-field behavior of rodents.

Dose and diameter relationships for facial, trigeminal, and acoustic neuropathies following acoustic neuroma radiosurgery

International Nuclear Information System (INIS)

Flickinger, John C.; Kondziolka, Douglas; Lunsford, L. Dade

1996-01-01

Purpose and objective: To define the relationships between dose and tumor diameter for the risks of developing trigeminal, facial, and acoustic neuropathies after acoustic neuroma radiosurgery, a large single-institution experience was analyzed. Materials and methods: Two hundred and thirty-eight patients with unilateral acoustic neuromas who underwent Gamma knife radiosurgery between 1987-1994 with 6-91 months of follow-up (median 30 months) were studied. Minimum tumor doses were 12-20 Gy (median 15 Gy). Transverse tumor diameter varied from 0.3-5.5 cm (median 2.1 cm). The relationships of dose and diameter to the development of cranial neuropathies were delineated by multivariate logistic regression. Results: The development of post-radiosurgery neuropathies affecting cranial nerves V, VII, and VIII were correlated with minimum tumor dose and transverse tumor diameter (P min for VIII where P=0.10). A comparison of the dose-diameter response curves showed the acoustic nerve to be the most sensitive to doses of 12-16 Gy and the facial nerve to be the least sensitive. Conclusion: The risks of developing trigeminal, facial, and acoustic neuropathies following acoustic neuroma radiosurgery can be predicted from the transverse tumor diameter and the minimum tumor dose using models constructed from data presently available

Building America Case Study: High-Velocity Small-Diameter Duct System, Pittsburgh, Pennsylvania

Energy Technology Data Exchange (ETDEWEB)

2017-04-01

This study tests the performance of a variable airflow small-diameter duct heating, ventilation, and air conditioning (HVAC) system in a new construction unoccupied low-load test house in Pittsburgh, Pennsylvania. The duct system was installed entirely in conditioned space and was operated from the winter through summer seasons. Measurements were collected on the in-room temperatures and energy consumed by the air handler and heat pump unit. Operation modes with three different volumes of airflow were compared to determine the ideal airflow scenario that maximizes room-to-room thermal uniformity while minimizing fan energy consumption. Black felt infrared imagery was used as a measure of diffuser throw and in-room air mixing. Measured results indicate the small-diameter, high velocity airflow system can provide comfort under some conditions. Solar heat gains resulted in southern rooms drifting beyond acceptable temperature limits. Insufficient airflow to some bedrooms also resulted in periods of potential discomfort. Homebuilders or HVAC contractors can use these results to assess whether this space conditioning strategy is an attractive alternative to a traditional duct system. The team performed a cost analysis of two duct system configurations: (1) a conventional diameter and velocity duct system, and (2) the small-diameter duct system. This work applies to both new and retrofit homes that have achieved a low heating and cooling density either by energy conservation or by operation in a mild climate with few heating or cooling degree days. Guidance is provided on cost trade-offs between the conventional duct system and the small-diameter duct system.

Safety and Effectiveness of UFE in Fibroids Larger than 10 cm

Energy Technology Data Exchange (ETDEWEB)

Bérczi, Viktor, E-mail: berczi@hotmail.com; Valcseva, Éva, E-mail: evapeneva@gmail.com; Kozics, Dóra, E-mail: dora.kozics@gmail.com; Kalina, Ildikó, E-mail: ilkalina@t-online.hu; Kaposi, Pál, E-mail: kaposipal@gmail.com [Semmelweis University, Department of Radiology and Oncotherapy (Hungary); Sziller, Péter, E-mail: psziller@t-online.hu; Várbíró, Szabolcs, E-mail: varbiroszabolcs@gmail.com [Semmelweis University, 2nd Department of Gynaecology and Obstetrics (Hungary); Botos, Erzsébet Mária, E-mail: erzsebetbotos@gmail.com [Semmelweis University, Department of Radiology and Oncotherapy (Hungary)

2015-10-15

IntroductionEarly literature suggested that the size of the uterus, the size of the dominant fibroid, and the amount of applied embolization particles would be the risk factors for major postprocedural complications, but recent publications have confuted these early results. The purpose of our study was to evaluate whether the size of the dominant fibroid would influence the complication rate and effectiveness in a large single-center cohort.Patients and MethodsFrom 28 April 2008 until 31 December 2012, 303 patients had uterine artery embolization (UAE). 262 patients had small [largest diameter <10 cm (Group 1)], 41 patients had large [largest diameter >10 cm (Group 2)] fibroid. UAE was performed from unilateral femoral access using 500–710 and 355–500 µm polyvinyl alcohol particles. Periprocedural and postprocedural complications and numerical analog quality-of-life scores (0—unbearable symptoms; 100—perfect quality of life) were listed and statistically analyzed.ResultsDuring the mean follow-up time [7.79 ± 5.16 (SD) month], data on 275 patients (275/303 = 90.8 %) were available. Quality-of-life score was 33.3 ± 23.5 and 33.5 ± 24.1 before, whereas 85.6 ± 16.0 and 81.5 ± 23.5 after UAE in Group 1 and Group 2, respectively, (Mann–Whitney U test one-sided, p = 0.365). There were 4 myoma expulsions, 1 acute myomectomy, and 2 acute hysterectomies reported from Group 1, meanwhile 1 myoma expulsion, 1 acute myomectomy, and 2 acute hysterectomies were documented from Group 2 (NS differences).ConclusionThere was no significant difference in the effectiveness and in the number of minor and major complications between fibroids with <10 cm largest diameter compared to those >10 cm.

SU-E-T-454: Impact of Air Gap On PDDs of 6 MV Photon Beam for Various Field Sizes in Inhomogeneous Phantoms

Energy Technology Data Exchange (ETDEWEB)

Oyewale, S [Cancer Centers of Southwest Oklahoma, Lawton, OK (United States); Pokharel [21st Century Oncology, Estero, FL (United States); Singh, H [Procure Proton Therapy Center, Oklahoma City, OK (United States); Islam, M [University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma (United States); Rana, S [ProCure Proton Therapy Center, Oklahoma City, OK (United States)

2015-06-15

Purpose: To investigate how the shape of air gap and its size will impact the percent depth doses (PDDs) of a 6MV photon beam for various field sizes. Methods: Two in-house phantoms were manufactured containing rectangular (phantom A) and circular (phantom B) air gaps. Both phantoms A and B were composed of same top layer (solid-water; 30×30cm{sup 2},5cm thickness) and bottom layer (solid-water; 30×30cm {sup 2},8cm thickness), but middle layer was varied to observe air gap effects and scatter contribution to the measurement point. In phantom A, a rectangular shaped air gap (30×30cm{sup 2},7cm thickness) was created by placing Styrofoam blocks between top and bottom layers of the phantom. In phantom B, middle layer was replaced by “inhomogenous block”, composed of acrylic plate (30×30cm{sup 2}, 4cm thickness) followed by PVC(30×30cm{sup 2},3cm thickness). Additionally, circular air gap was created by drilling a hole (diameter=2.8cm, length=7cm) at the center of “inhomogenous block”. In both phantoms, measurement readings were obtained at 13cm depth (i.e., 1cm after air gap) and depth of maximum dose(6MV energy; 100 MUs; field sizes ranged from 3×3cm{sup 2} to 10×10cm{sup 2}). The PDDs at 13cm depth were compared in both phantoms. Results: The measurements in both phantoms A and B showed an almost linear increase in PDDs with increasing field size, especially for smaller field sizes (from 3×3 to 7×7cm{sup 2}). For each field size, the PDD in phantom A was smaller compared to the one in phantom B. The difference in PDDs between two phantoms decreased with an increase in field size as the PDD difference decreased from 9.0% to 6.4%. Conclusion: The shape and size of air gap affect the PDD measurements in secondary build-up region as 6 MV primary beam traverses through the center of air gap. The scatter contribution due to increase in field size was more noticeable for field sizes ≤7×7cm{sup 2}.

Optic nerve sheath diameter on fat-saturated T2-weighted orbital MR imaging reflects intracranial pressure

International Nuclear Information System (INIS)

Watanabe, Arata; Kinouchi, Hiroyuki; Horikoshi, Toru; Uchida, Mikito; Sakatsume, Satoshi

2009-01-01

Although dilated optic nerve sheath (ONS) is observed in the setting of increased intracranial pressure (ICP) such as idiopathic intracranial hypertension or hydrocephalus, the relationship between ONS diameter and ICP is unclear. We analyzed the relationship between subdural pressure measured during surgery in patients with chronic subdural fluid collections and ONS diameter measured on MR images. Orbital thin slice fat-saturated MR images were obtained within 24 hours before surgery and ONS diameters were measured just behind the optic globe. Subdural pressure was measured using a manometer before opening the dura mater during surgery. Significant correlation was found between the ONS diameter and subdural pressure (y=0.0618x+4.8219. y: ONS diameter (mm), x: subdural pressure (cmH 2 O), correlation coefficient: 0.505). The ONS diameter before surgery (6.1±0.7 mm) was significantly reduced after surgery (4.8±0.9 mm, p=0.003). Increased ONS diameter on MR images is a strong indicator of increased ICP we propose 6 mm as the normal limit of diameter just behind the eyeball because this value corresponds to the upper normal limit of ICP of around 20 cmH 2 O with above mentioned approximate curve. (author)

Workplace performance of a loose-fitting powered air purifying respirator during nanoparticle synthesis

International Nuclear Information System (INIS)

Koivisto, Antti J.; Aromaa, Mikko; Koponen, Ismo K.; Fransman, Wouter; Jensen, Keld A.; Mäkelä, Jyrki M.; Hämeri, Kaarle J.

2015-01-01

Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 10 6 cm −3 . During such conditions, it is essential that the occupants in the room wear highly reliable high-performance respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying respirators, while workers were coating components with TiO 2 or Cu x O y nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 10 6 to 40 × 10 6 cm −3 , and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the respirator varied from 0.7 to 7.2 cm −3 . However, on average, tidal breathing was assumed to increase the respirator concentration by 2.3 cm −3 . The derived PPF exceeded 1.1 × 10 6 , which is more than 40 × 10 3 times the respirator assigned protection factor. We were unable to measure clear differences in the PPF of respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying respirator provides very efficient protection against nanoparticle inhalation exposure if used properly

Critical current density and microwave surface resistance of 5-cm-diameter YBCO films on LaAlO3 substrates prepared by MOD using an infrared image furnace

International Nuclear Information System (INIS)

Manabe, T.; Kondo, W.; Yamaguchi, I.; Sohma, M.; Tsuchiya, T.; Tsukada, K.; Mizuta, S.; Kumagai, T.

2005-01-01

Inductive critical current density (J c ) and microwave surface resistance (R s ) were investigated for 0.7-μm-thick epitaxial YBa 2 Cu 3 O 7-y (YBCO) films on 5-cm-diameter LaAlO 3 substrates prepared by a chemical solution-based metal organic deposition (MOD) process using an infrared image furnace. By varying the heating rate at ramp during the final heat treatment, we obtained various orientations of YBCO; the c- and a-axis orientation at a slower rate, i.e., 20-100 deg C/min while the pure c-axis orientation at a faster rate, 200 deg C/min. The c-axis-oriented YBCO films showed excellent superconducting properties; for example, a high inductive-J c (77 K) of 2.6 MA/cm 2 and low R s (12 GHz)'s of 0.24 and 0.52 mΩ at 50 and 77 K, respectively, by a sapphire rod resonator method. The c- and a-axis-oriented films exhibited a lower J c and a higher R s . It was found that the J c and R s values of MOD-derived YBCO films showed a strong correlation; approximately, R s is inversely proportional to J c . This correlation is in good agreement with a previous report by Ohshima et al. for sputtered-YBCO films on BaSnO 3 -buffered MgO substrates

Design and performances of the 5 cm microtron

International Nuclear Information System (INIS)

Zakharov, M.A.; Melekhin, V.N.; Sukhachev, V.Ya.

1979-01-01

Described is the 5 cm microtron with 14 orbits and the 10 MeV maximum energy of electron beam, the 10 μA pulse current and the 100 W average power. The electromagnet of the armoured type with the external diameter of 680 mm, the height of 260 mm, the pole gap of 62 mm is designed for generation of the 0.32 T magnetic field. The vacuum chamber is made of stainless steel and it is totally separated from the electromagnet. An accelerating resonator is inserted through the connection pipe. An intermetallic thermoemitter of the iridium-cerium alloy is used in the microtron. The acceleration regime of the first type with zero initial phases is used in the microtron. The prospects of utilization of the 5-cm microtron is illustrated

Entrainment and deposition studies in two-phase cross flow: comparison between air-water and steam-water in a square horizontal duct. Technical report (final)

International Nuclear Information System (INIS)

Berryman, R.J.; Ralph, J.C.; Wade, C.D.

1981-03-01

Air-water simulation studies of two phase steam water flow relevant to the upper plenum of a PWR during reflood situations have recently been undertaken at Harwell for the US Nuclear Regulatory Commission. In order to give confidence that the simulation fluids were capable of modelling the important features of the actual system, a relatively basic comparison experiment has been carried out. Water entrainment and deposition tests have been carried out on a pair of 2.5 cm diameter vertical rods mounted in a cross flow of steam or air in a 10.2 cm x 10.2 cm tunnel. The air and steam systems exhibited similar characteristics to one another. A 'critical' film flowrate was identified for the rods which, once reached, either by injection through the sinters or by entrainment from the main two phase stream, was not exceeded with further water addition. The 'critical' film flowrate decreased with increase of cross flow velocity and was lower for air than steam at the same velocity. The results from the air and steam tests were found to be reasonably well correlated on the basis of the cross flow momentum flux of the air or steam

Evaluation and comparison of quantitative and qualitative effects of scattering in air and water media in planar and SPECT imaging

International Nuclear Information System (INIS)

Saeed Sarkar; Akram Abehesht

2004-01-01

In this research the scatter fraction (%SF) in air and water media in both planar and tomographic imaging was evaluated in order to find the differences and assist the nuclear medicine specialists in interpreting the images.Two small Perspex cylinders of equal dimensions, diameter = 5 cm and height = 5 cm, with an angle of 1200 relative to each other was fixed at the bottom of a 22 cm diameter and 26 cm height Perspex cylinder to make a scattering phantom. One of the cylinders was filled with water representing soft tissue while the other one was left empty (air). The big cylinder was filled with water up to the upper level of small cylinders. 2.5 mCi of 99m Tc was mixed uniformly with the water in the big cylinder. Both planar and tomographic images of the phantom were obtained by a single head SPECT system with %20 energy windows. %SF is defined as %SF = (cold/hot) where, cold and hot are the number of counts in ROIs of each small cold cylinder and big hot cylinder respectively. ROIs selected around the image of each cylinder were equal to the exact size of the objects. In planar image the %SF was found to be %3.24±0.03 and % 3.23±0.03 in air and water respectively. On the other hand the %SF in SPECT images were %6.12±0.05 and %4.47±0.04 in air and water respectively. In planar image no difference is seen in %SF between small cylinders containing air and water whereas in SPECT image the %SF in air cylinder is %27 more than the water cylinder. This has caused more blurred edges for the image of air cylinder. Lower %SF in the small water cylinder may be caused by absorption of scattered events in the water medium. The %SF in SPECT is almost twice the planar imaging for water medium, whereas on the average the %SF in planar imaging is almost %60 of the SPECT. These differences account for better contrast and sharper edges of small cold cylinders in planar imaging. (authors)

Pure air-plasma bullets propagating inside microcapillaries and in ambient air

KAUST Repository

Lacoste, Deanna; Bourdon, Anne; Kuribara, Koichi; Urabe, Keiichiro; Stauss, Sven; Terashima, Kazuo

2014-01-01

This paper reports on the characterization of air-plasma bullets in microcapillary tubes and in ambient air, obtained without the use of inert or noble gases. The bullets were produced by nanosecond repetitively pulsed discharges, applied in a dielectric barrier discharge configuration. The anode was a tungsten wire with a diameter of 50 μm, centered in the microcapillary, while the cathode was a silver ring, fixed on the outer surface of the fused silica tube. The effects of the applied voltage and the inner diameter of the microcapillary tube on the plasma behavior were investigated. Inside the tubes, while the topology of the bullets seems to be strongly dependent on the diameter, their velocity is only a function of the amplitude of the applied voltage. In ambient air, the propagation of air bullets with a velocity of about 1.25 ×105 m s-1 is observed.

Pure air-plasma bullets propagating inside microcapillaries and in ambient air

KAUST Repository

Lacoste, Deanna

2014-11-04

This paper reports on the characterization of air-plasma bullets in microcapillary tubes and in ambient air, obtained without the use of inert or noble gases. The bullets were produced by nanosecond repetitively pulsed discharges, applied in a dielectric barrier discharge configuration. The anode was a tungsten wire with a diameter of 50 μm, centered in the microcapillary, while the cathode was a silver ring, fixed on the outer surface of the fused silica tube. The effects of the applied voltage and the inner diameter of the microcapillary tube on the plasma behavior were investigated. Inside the tubes, while the topology of the bullets seems to be strongly dependent on the diameter, their velocity is only a function of the amplitude of the applied voltage. In ambient air, the propagation of air bullets with a velocity of about 1.25 ×105 m s-1 is observed.

Tree height-diameter and yield functions for Gmelina arborea (roxb ...

African Journals Online (AJOL)

Data were analyzed using descriptive statistics and regression analysis. Linear, logarithmic, polynomial, power and exponential height-diameter and stem volume models were fitted to the dataset. The predictor was tree Dbh (cm). The developed models were assessed using coefficient of determination (R2) and root mean ...

The determination of nitrogen dioxide in ambient air with free hanging filters as passive samplers, and a new calibration method using fritted bubblers

NARCIS (Netherlands)

Heeres, P.; Setiawan, R.; Krol, M.C.; Adema, E.H.

2009-01-01

This paper describes two new methods for the determination of NO2 in the ambient air. The first method consists of free hanging filters with a diameter of 2.5 cm as passive samplers. The filters are impregnated with triethanolamine to bind NO2. With standard colorimetrical analysis, the amount of

Correlation of inferior vena cava (ivc) diameter and central venous pressure (cvp) for fluid monitoring in icu

International Nuclear Information System (INIS)

Khalil, A.; Hayat, A.

2015-01-01

To determine intravascular fluid status in critically ill patients using inferior vena cava diameter and correlating it with central venous pressure. Study Design: Cross sectional study. Place and Duration of Study: Intensive care department, Military Hospital Rawalpindi from Jan 2013 to Aug 2013. Material and Methods: We included 115 adult patients of both genders in age range of 18 to 87 years by consecutive sampling admitted in intensive care unit. Ultrasound guided IVC diameter was assessed in supine patients. Data was simultaneously collected from the CVP catheter. Variables included in study were age, gender, CVP, IVC diameter. Results: CVP ranged from -4 to 26 cm H/sub 2/O with mean of 8 cm H/sub 2/O (SD = 6.24). Mean IVC diameters increased with increase in CVP. Correlation between CVP and max IVC diameter was moderate and significant (r = 0.53, p < 0.001). Correlation between CVP and min IVC diameter was also moderate and significant (r = 0.58, p < 0.001). Conclusion: A simple bedside sonography of inferior vena cava diameter correlates well with extremes of CVP values and can be helpful in assessing intravascular fluid status in these patients. (author)

Adimensional temperature field of air around a horizontal heating cylinder empirical equations, for free convection

Energy Technology Data Exchange (ETDEWEB)

Diez, R.; Dolz, M. Belda, R.; Herraez, J.V.

1988-01-01

The analytical process follow to obtain the adimensional temperature field of air around a horizontal isothermal cylinder of 1 cm diameter and 10.5 length is presented. The equations defining the adimensional temperature variation with the adimensional distance are given for each semiplane that the total field was divide. Comparison of experimental results with obtained of that equations are also carried out and the validity in each case discussed.

Studies of flow configurations up to the critical phenomenon at 80 kg/cm2

International Nuclear Information System (INIS)

Raisson, C.

1968-12-01

Tests performed at 80 kg/cm 2 allow to study two-phase flows and their evolution up to the critical heating. Three measurement methods have been used simultaneously: thermocouples, conductivity probe, short length pressure drops after the output. The 282 cm length stainless steel channel has an internal diameter of 0.6 cm and a wall thickness of 0.2 cm. Flow configuration results are comparable to those of the literature with some precision regarding some transition zones. Two critical heating regimes have been highlighted. The results demonstrate the interest of the method and the importance of hydrodynamic parameters on the critical heating phenomenon [fr

Sonographic Measurement of AP Diameter and Wall Thickness of the Gallbladder

International Nuclear Information System (INIS)

Chung, S.K.; Lee, J. S.; Huh, S. J.; Baek, I. S.

1982-01-01

Call bladder size and wall thickness are important in the assessment of the pathologic condition. Authors have measured AP diameter of gallbladder and evaluated the change of all thickness between fasting and postprandial state. The results were as follows: 1. The mean of AP diameter was 2.18+0.49cm 2. The wall thickness was 2.7+0.6mm in fasting state and 3.3+0.8mm after meal. 3. The increase of wall thickness after fat meal was significant statistically(p<.001)

Comparison between air CT and MRI in the detection of small acoustic neurinomas

Energy Technology Data Exchange (ETDEWEB)

Kamei, Tetsuya; Nakashima, Aiko; Seto, Hikaru; Kakishita, Masao

1989-02-01

Air CT proved useful in yielding images of acoustic tumors as an air filling defect in 11 (24%) of 46 patients. Six of the 11 tumors were small ones of less than 1 cm in diameter. Air CT was also able to exclude an intracanalicular tumor in 29 patients (63%). MRI was performed for comparison in eight patients (nine tumors) already diagnosed by air CT as having an acoustic tumor. MRI detected eight (89%) of nine tumors. A false negative result on MRI was obtained only in one intracanalicular tumor (4.3 mm in size). This was considered to be attributable to limitations of spatial resolution including the wide slice thickness. A protocol for radiological investigation and management of patients whose clinical symptoms and/or audiovestibular examination are highly indicative of acoustic tumor is proposed and discussed. (author).

Comparison between air CT and MRI in the detection of small acoustic neurinomas

International Nuclear Information System (INIS)

Kamei, Tetsuya; Nakashima, Aiko; Seto, Hikaru; Kakishita, Masao

1989-01-01

Air CT proved useful in yielding images of acoustic tumors as an air filling defect in 11 (24%) of 46 patients. Six of the 11 tumors were small ones of less than 1 cm in diameter. Air CT was also able to exclude an intracanalicular tumor in 29 patients (63%). MRI was performed for comparison in eight patients (nine tumors) already diagnosed by air CT as having an acoustic tumor. MRI detected eight (89%) of nine tumors. A false negative result on MRI was obtained only in one intracanalicular tumor (4.3 mm in size). This was considered to be attributable to limitations of spatial resolution including the wide slice thickness. A protocol for radiological investigation and management of patients whose clinical symptoms and/or audiovestibular examination are highly indicative of acoustic tumor is proposed and discussed. (author)

Individual tree diameter, height, and volume functions for longleaf pine

Science.gov (United States)

Carlos A. Gonzalez-Benecke; Salvador A. Gezan; Timothy A. Martin; Wendell P. Cropper; Lisa J. Samuelson; Daniel J. Leduc

2014-01-01

Currently, little information is available to estimate individual tree attributes for longleaf pine (Pinus palustris Mill.), an important tree species of the southeastern United States. The majority of available models are local, relying on stem diameter outside bark at breast height (dbh, cm) and not including stand-level parameters. We developed...

Establishment of dosimetric references for high energy X-ray beams of very small field sizes (≤ 1 cm2) used in radiotherapy

International Nuclear Information System (INIS)

Dufreneix, Stephane

2014-01-01

The French primary standard dosimetry laboratory 'Laboratoire National Henri Becquerel' is in charge of the establishment of dosimetric standards for ionizing radiation beams. Absolute dose measurements are thus available for X-Ray beams used in radiotherapy for field sizes between 10 and 2 cm. Since the miniaturization of absolute dosimeters is not possible for smaller field sizes, a dose area product (DAP) has been suggested as a substitute to the absorbed dose at a point.In order to measure a DAP with dosimeters which sensitive surface is larger than the beam, a graphite calorimeter with a sensitive surface of 3 cm diameter was designed, built and tested. An ionization chamber with the same diameter was realized and tested to transfer the dosimetric references to the end users. Its calibration factor in terms of DAP was determined in circular beams of 2, 1 and 0.75 cm diameter with an uncertainty smaller than 0.7 %. The two-Dimension relative dose distribution was measured thanks to a diamond dosimeter, a PinPoint ionization chamber and gafchromic films, using a specific protocol. Both approaches, respectively based on a PDS and an absorbed dose to water at a point, were in good agreement in the 2 cm beam. Correction factors determined from Monte Carlo simulations and measured dose distributions were needed for this comparison. The calibration factor of the large ionization chamber in the 1 and 0.75 cm diameter beams were in good agreement within the uncertainties but a gap of -2.6 % was found with the one established in the 2 cm diameter beam. As a result, the DAP can be used if the sensitive surface is much larger than the beam section. (author) [fr

Workplace performance of a loose-fitting powered air purifying respirator during nanoparticle synthesis

Energy Technology Data Exchange (ETDEWEB)

Koivisto, Antti J., E-mail: jok@nrcwe.dk [National Research Centre for the Working Environment (Denmark); Aromaa, Mikko [Tampere University of Technology, Department of Physics (Finland); Koponen, Ismo K. [National Research Centre for the Working Environment (Denmark); Fransman, Wouter [TNO (Netherlands); Jensen, Keld A. [National Research Centre for the Working Environment (Denmark); Mäkelä, Jyrki M. [Tampere University of Technology, Department of Physics (Finland); Hämeri, Kaarle J. [University of Helsinki, Department of Physics (Finland)

2015-04-15

Nanoparticle (particles with diameter ≤100 nm) exposure is recognized as a potentially harmful size fraction for pulmonary particle exposure. During nanoparticle synthesis, the number concentrations in the process room may exceed 10 × 10{sup 6} cm{sup −3}. During such conditions, it is essential that the occupants in the room wear highly reliable high-performance respirators to prevent inhalation exposure. Here we have studied the in-use program protection factor (PPF) of loose-fitting powered air purifying respirators, while workers were coating components with TiO{sub 2} or Cu{sub x}O{sub y} nanoparticles under a hood using a liquid flame spray process. The PPF was measured using condensation particle counters, an electrical low pressure impactor, and diffusion chargers. The room particle concentrations varied from 4 × 10{sup 6} to 40 × 10{sup 6} cm{sup −3}, and the count median aerodynamic diameter ranged from 32 to 180 nm. Concentrations inside the respirator varied from 0.7 to 7.2 cm{sup −3}. However, on average, tidal breathing was assumed to increase the respirator concentration by 2.3 cm{sup −3}. The derived PPF exceeded 1.1 × 10{sup 6}, which is more than 40 × 10{sup 3} times the respirator assigned protection factor. We were unable to measure clear differences in the PPF of respirators with old and new filters, among two male and one female user, or assess most penetrating particle size. This study shows that the loose-fitting powered air purifying respirator provides very efficient protection against nanoparticle inhalation exposure if used properly.

BIOMASS IN Eucalyptus viminalis Labill. PLANTATIONS IN BUENOS AIRES PROVINCE, ARGENTINA

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Paula Ferrere

2009-10-01

Full Text Available The present work was developed in the West of Buenos Aires Province (Argentina with the objective of adjusting functions of biomass of individual trees, in their different compartments and in the understorey. Stands of Eucalyptus viminalis Labill. were identified, with ages between 4 and 14 years-old. Twenty-one individuals were felled with diameters ranging from 9,2 to 32,5 cm. Simple and multiple regression models were developed and volume, branch leaf and stem biomass were estimated. The best volume equations were based on lineal models and the most adequate behavior was obtained with d2. To estimate leaf, branch and stem, ln-ln models have been suggested, with diameter and h or only diameter. The leaf biomass presented the weakest adjustment. The distribution of trees biomass agrees with the bibliography. The proportion of crown biomass decreases with age; on the other hand, the proportion of stem biomass increases with age.

Evaluation of a xenogeneic acellular collagen matrix as a small-diameter vascular graft in dogs--preliminary observations.

Science.gov (United States)

Nemcova, S; Noel, A A; Jost, C J; Gloviczki, P; Miller, V M; Brockbank, K G

2001-01-01

Autogenous veins are the materials of choice for arterial reconstruction. In the absence of autogenous material, prosthetic materials are used. However, vascular prostheses of less than 0.4 cm in diameter have low long-term patency. This study was designed to determine if cells would infiltrate an engineered xenogeneic biomaterial used as a small diameter arterial graft in dogs and, if so, to determine the phenotype of the infiltrating cells. Nine acellular xenogeneic grafts (0.4 cm in diameter, 5 cm long), composed of porcine collagen derived from the submucosa of the small intestine and type I bovine collagen, were implanted as end to-end interposition grafts in femoral arteries of five male mongrel dogs (total of nine grafts). All dogs received daily aspirin (325 mg). Patency of implanted grafts was monitored weekly by Duplex ultrasonography. After 9 weeks, or earlier in case of blood flow reduction by at least 75%, grafts were explanted and prepared for light or electron microscopy to evaluate cellularization. Eight of nine grafts remained patent up to 9 weeks. At explant, diameters were 0.31 +/- 0.02 cm at the midgraft, and 0.14 +/- 0.01 and 0.19 +/- 0.01 cm at the proximal and distal anastomoses. At explant, cells of mesenchymal origin (endothelial cells, smooth muscle cells, myofibroblasts) were embedded in the extracellular matrix of the graft scaffold. Minimal evidence of cellular inflammatory reaction and no aneurysmal dilatation or thrombus formation was detected. Variable degrees of hyperplasia were present at proximal and distal anastomoses. This preliminary study demonstrates that a collagen-based xenogeneic biomaterial provides a scaffold for cellularization when used for arterial reconstruction in dogs.

Ecological Importance of Small-Diameter Trees to the Structure, Diversity and Biomass of a Tropical Evergreen Forest at Rabi, Gabon.

Science.gov (United States)

Memiaghe, Hervé R; Lutz, James A; Korte, Lisa; Alonso, Alfonso; Kenfack, David

2016-01-01

Tropical forests have long been recognized for their biodiversity and ecosystem services. Despite their importance, tropical forests, and particularly those of central Africa, remain understudied. Until recently, most forest inventories in Central Africa have focused on trees ≥10 cm in diameter, even though several studies have shown that small-diameter tree population may be important to demographic rates and nutrient cycling. To determine the ecological importance of small-diameter trees in central African forests, we used data from a 25-ha permanent plot that we established in the rainforest of Gabon to study the diversity and dynamics of these forests. Within the plot, we censused 175,830 trees ≥1 cm dbh from 54 families, 192 genera, and 345 species. Average tree density was 7,026 trees/ha, basal area 31.64 m2/ha, and above-ground biomass 369.40 Mg/ha. Fabaceae, Ebenaceae and Euphorbiaceae were the most important families by basal area, density and above-ground biomass. Small-diameter trees (1 cm ≥ dbh tree population, 16.5% of basal area, and 4.8% of the above-ground biomass. They also had diversity 18% higher at family level, 34% higher at genus level, and 42% higher at species level than trees ≥10 cm dbh. Although the relative contribution of small-diameter trees to biomass was comparable to other forests globally, their contribution to forest density, and diversity was disproportionately higher. The high levels of diversity within small-diameter classes may give these forests high levels of structural resilience to anthropogenic/natural disturbance and a changing climate.

Ground level cosmic ray pulse height spectrum of a 7. 5 cm diameter spherical NaI(Tl) scintillation detector for energy region below 5 MeV

Energy Technology Data Exchange (ETDEWEB)

Nagaoka, Toshi; Saito, Kimiaki; Moriuchi, Shigeru

1988-09-01

Ground level cosmic ray pulse height spectrum of a 7.5 cm diameter spherical NaI(Tl) scintillation detector was evaluated through stripping operation based on a pulse height spectrum measured on the sea and high precision response functions of the detector for U-series, Th-series and /sup 40/K. The exposure rate calculated from the determined cosmic ray pulse height spectrum was 0.21 R/h eq., which agreed well with that obtained from another method. The shape of the pulse height spectrum showed similarity to that measured at the altitude of 16,000 ft, especially in the energy region of 0 to 3 MeV. The principle of the adopted method is rather plain, however, the reliability of the spectrum is satisfactory. As the pulse height spectrum is a common information to any analytical method for environmental gamma ray using NaI(Tl) scintillation detector, it is expected to be used for simple and precise separation of cosmic ray component involved in the enviromental pulse height spectrum.

Ground level cosmic ray pulse height spectrum of a 7.5 cm diameter spherical NaI(Tl) scintillation detector for energy region below 5 MeV

International Nuclear Information System (INIS)

Nagaoka, Toshi; Saito, Kimiaki; Moriuchi, Shigeru

1988-01-01

Ground level cosmic ray pulse height spectrum of a 7.5 cm diameter spherical NaI(Tl) scintillation detector was evaluated through stripping operation based on a pulse height spectrum measured on the sea and high precision response functions of the detector for U-series, Th-series and 40 K. The exposure rate calculated from the determined cosmic ray pulse height spectrum was 0.21 μR/h eq., which agreed well with that obtained from another method. The shape of the pulse height spectrum showed similarity to that measured at the altitude of 16,000 ft, especially in the energy region of 0 to 3 MeV. The principle of the adopted method is rather plain, however, the reliability of the spectrum is satisfactory. As the pulse height spectrum is a common information to any analytical method for environmental gamma ray using NaI(Tl) scintillation detector, it is expected to be used for simple and precise separation of cosmic ray component involved in the enviromental pulse height spectrum. (author)

A small diameter, flexible, all attitude, self-contained germanium spectrometer. Operator's manual

International Nuclear Information System (INIS)

Bordzindki, R.L.; Lepel, E.A.; Reeves, J.H.; Kohli, R.

1997-05-01

The end of the Cold War has brought about tremendous changes in the nuclear complex of the Department of Energy. One of the many changes has been the shutdown or decommissioning of many facilities that performed nuclear work. One of the steps in the process of decommissioning a facility involves the decontamination or removal of drain lines or pipes that may have carried radioactive materials at one time. The removal of all these pipes and drain lines to a nuclear disposal facility could be quite costly. It was suggested by Pacific Northwest National Laboratory (PNNL) that a germanium spectrometer could be built that could fit through straight pipes with a diameter as small as 5.08 cm (2 inches) and pass through curved pipes with a diameter as small as 7.6 cm (3 inches) such as that of a 3-inch p-trap in a drain line. The germanium spectrometer could then be used to simultaneously determine all gamma-ray emitting radionuclides in or surrounding the pipe. By showing the absence of any gamma-ray emitting radionuclides, the pipes could then be reused in place or disposed of as non-radioactive material, thus saving significantly in disposal costs. A germanium spectrometer system has been designed by PNNL and fabricated by Princeton Gamma Tech (PGT) that consists of three segments, each 4.84 cm in diameter and about 10 cm in length. Flexible stainless steel bellows were used to connect the segments. Segment 1 is a small liquid nitrogen reservoir. The reservoir is filled with a sponge-like material which enables the detector to be used in any orientation. A Stirling cycle refrigerator is under development which can replace the liquid nitrogen reservoir to provide continuous cooling and operation

Smaller Anterior Cruciate Ligament Diameter Is a Predictor of Subjects Prone to Ligament Injuries: An Ultrasound Study

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Parag Suresh Mahajan

2015-01-01

Full Text Available Purpose. To test if diameter of normal anterior cruciate ligament (ACL can be measured by ultrasound (US, to see if there is a relationship between smaller ACL diameter and ACL injury, and to assess agreement between radiologists in measuring ACL diameter in cases and matched controls. Materials and Methods. In this ethics committee-approved study, maximum diameter of ACL near tibial insertion site was measured by static and dynamic US study in 25 normal contralateral knees of subjects who suffered noncontact ACL injury and in 25 matched control subjects. Results. ACL was visualized as a thick linear hypoechoic band inserted approximately 11 mm caudal to the tibial plateau and the intercondylar eminence. Maximum diameter of contralateral ACL near tibial insertion site among injured subjects was significantly smaller than in noninjured subjects (0.62 ± 0.07 cm versus 0.81 ± 0.06 cm; P<0.0001. In the regression analysis, the diameter of ACL near tibial insertion site was found significantly proportional to body weight and not significantly associated to height, gender, and age. Conclusion. Diameter of normal ACL near tibial insertion site can be measured by US and the maximum diameter is significantly smaller among subjects with noncontact ACL injury. US is a promising modality that can be used as an excellent screening test to detect subjects especially aspiring athletes prone to ACL injury. Very strong agreement was observed between radiologists in measuring ACL diameter.

In vitro protocol for validating interface pressure sensors for therapeutic compression garments: Importance of sphygmomanometer placement and initial cuff diameter

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Inhwa Jung

2018-02-01

Full Text Available An optimal protocol is needed to validate the performance of future interface pressure sensors for compression garments when using a sphygmomanometer. PicoPress® was used on a rigid plastic cylinder (r=4 cm. An FDA-cleared aneroid sphygmomanometer was used to apply pressures from 10-60 mmHg with a diameter of 8 cm or 12 cm placed either beneath the sphygmomanometer’s airbag or fabric cuff. A two-tail t-test was performed (P<0.05 for significance for all applied pressures. PicoPress® outputs vary with sensor placement (airbag vs fabric cuff and the initial cuff diameter. Sensor placement overlying the sphygmomanometer’s fabric cuff compared to the airbag led to significantly higher pressures (37%-135% depending on the cuff diameter size. These differences were nearly all statistically significant (P<0.05. Validation of new interface pressure sensors deploying a sphygmomanometer for calibration should specify the location of sensor placement location and initial diameter with a preference for placement under the airbag.

Plasma flame for mass purification of contaminated air with chemical and biological warfare agents

International Nuclear Information System (INIS)

Uhm, Han S.; Shin, Dong H.; Hong, Yong C.

2006-01-01

An elimination of airborne simulated chemical and biological warfare agents was carried out by making use of a plasma flame made of atmospheric plasma and a fuel-burning flame, which can purify the interior air of a large volume in isolated spaces such as buildings, public transportation systems, and military vehicles. The plasma flame generator consists of a microwave plasma torch connected in series to a fuel injector and a reaction chamber. For example, a reaction chamber, with the dimensions of a 22 cm diameter and 30 cm length, purifies an airflow rate of 5000 lpm contaminated with toluene (the simulated chemical agent) and soot from a diesel engine (the simulated aerosol for biological agents). Large volumes of purification by the plasma flame will free mankind from the threat of airborne warfare agents. The plasma flame may also effectively purify air that is contaminated with volatile organic compounds, in addition to eliminating soot from diesel engines as an environmental application

IMPACT TESTING OF MATERIALS USING AN EIGHT-INCH AIR GUN AND COMPUTER REDUCTION OF DATA

Energy Technology Data Exchange (ETDEWEB)

Thorne, L. F.

1973-10-01

A mechanical shock actuator has been converted into an air gun capable of firing 8-inch-·diameter (20.32 cm) projectiles to velocities exceeding 1000 fps (304.8 m/ s). This new capability has been used to study the effect of impact velocity upon the energy.absorbed by crushable materials. Shockpulse data is reduced by computer techniques and test results are displayed in either tabular or graphic format by use of the C DC 6600 Calcomp plotter.

Exploration of the optimal diameter cut-off value in patients with nonfunctional adrenal tumor suitable for surgery

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Dan-dan LIU

2016-12-01

Full Text Available Objective 　To analyze the pathology of the patients with nonfunctional adrenal tumor (NFA, and explore the optimal diameter cut-off value. Methods 　The clinical data of 243 patients with NFA, evaluated in the Department of Endocrinology and operated in the Department of Urology of General Hospital of Chinese PLA from Feb. 1996 to Jan. 2016, were collected. The patients were divided into two groups according to pathology: those in real demand of surgery were classified to the surgery-need group (n=57, while the others were categorized as the surgery-unwanted group (n=186. The general situation, pathological type and tumor diameter of the two groups and the factors affecting the surgery were analyzed, and the ROC curve was used to explore the optimal surgery cut-off value, which represents the maximum value of the sum of sensitivity and specificity. Results 　Of the 57 patients in surgery-need group (27 males and 30 females, the lesions were on the right in 31 cases, on the left in 25 cases, and on bilateral sides in 1 case; the median of lesion diameter was 4.5cm, and the average age was 41.5±12.1 years old. Of the 186 patients in surgery-unwanted group (87 males and 99 females, the lesions were on the right in 99 cases, on the left in 86 cases, and on bilateral sides in 1 case; the median of lesion diameter was 3.0cm, and the average age was 50.6±10.9 years old. Logistic regression revealed that lesion diameter might be a risk factor (OR=1.340, 95%CI 1.266-1.418, P=0.000 and age be a protective factor (OR=0.942, 95%CI 0.929-0.955, P=0.000 for real demand of surgery. The area under the ROC curve (AUC of lesion diameter was 0.757(95%CI 0.681-0.833. The optimal cut-off value was 4.1cm (sensitivity 60.7% and specificity 83.0%. Conclusions 　Younger patients with bigger lesion diameter may have greater possibility for surgery. The optimal surgery cut-off value of the lesion diameter is 4.1cm. DOI: 10.11855/j.issn.0577-7402.2016.11.11

Large diameter interseam boreholes: their usage to improve underground environments

Energy Technology Data Exchange (ETDEWEB)

Pickering, A.J. (Nottingham University, Nottingham (United Kingdom). Dept. of Mineral Resources Engineering)

1993-07-01

Development of drilling techniques for larger diameter holes over the last fifteen years has indicated their considerable potential to assist with quickly improving environmental facilities and services to high output coal faces. In Nottinghamshire, as well as in several other regions, mines have utilised interseam boreholes, fully lined, to improve inbye air flows with subsequent reduction of face temperatures, dust and firedamp levels. Some further holes have additionally been adapted quickly to increase firedamp drainage capacities and also to improve service facilities such as compressed air, electrical power and water, and access. A wide range of borehole sizes are employed, ranging from 0.35 m, with integral steel lining, up to a maximum of 2.5 m in diameter, fully concrete lined. The Nottinghamshire Group Sinking and Tunnelling Engineer provides a full range of drilling facilities. The most popular large diameter holes with a potential of 1.8 m in diameter, over 200 m in vertical depth, employs a Robins, type 23R, raise borer which has been in use up and down the country since 1977. A Fosroc CGR10 type, techgrout is applied after boring is completed to provide the essential smooth lining. The application of this lining utilises a special rubber former developed locally, essentially knitting strata cracks, beddings and any local overbreak of the holes. The former or 'sausage' is used in a similar manner to correct and repair boreholes which have been in use for some time. 4 refs., 6 figs., 1 tab.

Uniform laser ablative acceleration of targets at 1014 W/cm2

International Nuclear Information System (INIS)

Obenschain, S.P.; Whitlock, R.R.; McLean, E.A.; Ripin, B.H.; Price, R.H.; Phillion, D.W.; Campbell, E.M.; Rosen, M.D.

1982-01-01

We present the first detailed investigations of the ablative acceleration of planar targets while simultaneously using high irradiance (10 14 W/cm 2 ), large focal diameters (1 mm) and long laser pulse duration (3 nsec). Included are measurements of target preheat, ablation pressures and uniformity achieved under these conditions. Targets were accelerated to high velocities with velocity profile uniformity approaching that required for high gain pellet implosions

A radioactive aerosols in air monitoring system - 'ASIA'

International Nuclear Information System (INIS)

Belaish, I.; Levinson, S.; Pelled, O.; German, U.; Laichter, Y.; Gonen, E.; Wengrowicz, U.; Tirosh, D.; Barak, D.

1997-01-01

A continuous air monitoring system called 'ASIA' (Aerosols Sampler In Air) was developed at the NRCN for monitoring and measuring the concentration of airborne alpha emitting radionuclides such as Radon or natural Uranium. The 'ASIA' is a stationary multi-channel analyzer based system. The air passes through a 2.5 cm diameter filter and the radioactivity accumulated on it is monitored by a Silicon solid state detector. The sampling unit can be separated from the display and control unit to enable environment sampling close to the workers. The ASIA uses modern hardware and software in order to improve noise and background reduction and to allow friendly and flexible use. Remote communication is also available. The spectrum and additional data are displayed on line. The system was checked according to ANSI N42.17B -1989. The linearity and efficiency were evaluated by using various alpha sources. The Minimum Detectable Activity (MDA) and Decision Limit (Lc) were calculated according to ANSI N13.30. Long time stability measurements were performed using a natural Uranium source. (authors)

EFFECTS OF PLANTING SPACE AND HARVEST TIME ON THE NUMBER, WEIGHT AND DIAMETER OF MARIGOLD (CALENDULA OFFICINALIS L. FLOWERS

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Nada Parađiković

2013-06-01

Full Text Available The study was conducted during 2010 in marigold (Calendula officinalis L. to determine the effects of three plant densities (plant density A - 65 cm x 35 cm; plant density B - 65 cm x 25 cm; plant density C – 55 cm x 25 cm and harvest time on the number, weight and diameter of marigold flowers. The results showed that the plant density significantly influenced the number of flowers per plant and flower weight. The largest number of flowers per plant was recorded in the plant density B (13.2 and the lowest (9.87 in the plant density C. The lowest flower weight was recorded in the plant density C (1.31 g and was statistically lower than the flower weight in the plant densities A (1.42 g and B (1.38 g. The plant density significantly influenced the number of flowers on side branches, being the highest in the plant density B. The diameter of the marigold flower was not significantly influenced by the plant density. During the experiment, a total of 13 harvests were achieved. The greatest number of flowers per plant was harvested in the eighth, ninth and tenth harvest, while the largest flower weight was measured in the fifth and twelfth harvest. On the average, the number of flowers per plant / harvest was 11.63 and the weight of flowers was 1.38 g. Diameter of marigold flowers ranged from 2.89 cm to 3.59 cm in the thirteenth and the third harvest, respectively. The number of flowers on side branches per plant / harvest was 11.61.

Correlations between some physiographic factors and diameter, height and cone characteristics in stone pine (Pinus pinea L. afforestation areas in Balıkesir-Burhaniye region

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Ali Ömer Üçler

2017-11-01

Full Text Available In this study, effects of some physiographic factors (aspect, slope and elevation on breast diameter, height and cone properties (cone weight, number of cones, cone width and cone length in stone pine (Pinus pinea L. afforestation areas in Balıkesir-Burhaniye region were investigated. To determine to effects of physiographic conditions, study area is separated according to aspect, slope and elevation groups. Aspect is separated two groups which are shady aspect (B1 and sunny aspect (B2. Slope is separated two groups which are small from 36 percent (E1 and big from 36 percent (E2. Elevation also is separated two groups which are under 400 meters (Y1 and over 400 meters (Y2. Sample areas were scattering to land classifications by using Stratified Sampling Method. Thus, each aspect, slope and elevation classifications were obtained from sample area where are provided from 32 different areas. Tree heights, the diameter at breast height and cone number were measured on saplings. In addition, in each sample area five Pinus pinea trees were selected. It was measured cone diameter, cone height and air-dries weight values of cones which are picked from selecting trees. According to statistical analysis results, aspect effects to tree heights, cone number and cone weight; slope effects the diameter at breast height, cone number and cone diameter; elevation effects the diameter at breast height, tree height, cone number and cone weight. In terms of tree height and diameter values; the highest average breast height diameter was found in the B1E1Y1 with 13.6 cm, and the highest average height value was found in the B2E2Y2 by interaction. In terms of cone characteristics; with the highest average cone number of 8.5 in B1E1Y1, the highest mean cone weight in B1E1Y1 with 232 gr and the highest cone diameter in B2E2Y1 with 5.4 cm. According to the results of correlation analysis; it was determined that slope and elevation factors have positive effect on breast

5cm aperture dipole studies

International Nuclear Information System (INIS)

McInturff, A.D.; Bossert, R.; Carson, J.; Fisk, H.E.; Hanft, R.; Kuchnir, M.; Lundy, R.; Mantech, P.; Strait, J.

1986-01-01

The results obtained during the evolution of the design, construction, and testing program of the design ''B'' dipole are presented here. Design ''B'' is one of the original three competing designs for the Superconducting Super Collider ''SSC'' arc dipoles. The final design parameters were as follows: air cored (less than a few percent of the magnetic field derived from any iron present), aluminum collared, two layered winding, 5.5T maximum operating field, and a 5 cm cold aperture. There have been fourteen 64 cm long 5 cm aperture model dipoles cold tested (at 4.3K and less) in this program so far. There was a half length full size (6m) mechanical analog (M-10) built and tested to check the cryostat's mechanical design under ramping and quench conditions. Several deviations from the ''Tevatron'' dipole fabrication technique were incorporated, for example the use of aluminum collars instead of stainless steel. The winding technique variations explored were ''dry welding,'' a technique with the cable covered with Kapton insulation only and ''wet winding'' where the Kapton was covered with a light coat of ''B'' stage epoxy. Test data include quench currents, field quality (Fourier multipole co-efficients), coil magnetization, conductor current performance, and coil loading. Quench current, loss per cycle, and harmonics were measured as a function of the magnitude and rate of change of the magnetic field, and helium bath temperature

Bearing capacity of helical pile foundation in peat soil from different, diameter and spacing of helical plates

Science.gov (United States)

Fatnanta, F.; Satibi, S.; Muhardi

2018-03-01

In an area dominated by thick peat soil layers, driven piles foundation is often used. These piles are generally skin friction piles where the pile tips do not reach hard stratum. Since the bearing capacity of the piles rely on the resistance of their smooth skin, the bearing capacity of the piles are generally low. One way to increase the bearing capacity of the piles is by installing helical plates around the pile tips. Many research has been performed on helical pile foundation. However, literature on the use of helical pile foundation on peat soil is still hardly found. This research focus on the study of axial bearing capacity of helical pile foundation in peat soil, especially in Riau Province. These full-scale tests on helical pile foundation were performed in a rectangular box partially embedded into the ground. The box is filled with peat soil, which was taken from Rimbo Panjang area in the district of Kampar, Riau Province. Several helical piles with different number, diameter and spacing of the helical plates have been tested and analysed. The tests result show that helical pile with three helical plates of uniform diameter has better bearing capacity compared to other helical piles with varying diameter and different number of helical plates. The bearing capacity of helical pile foundation is affected by the spacing between helical plates. It is found that the effective helical plates spacing for helical pile foundation with diameter of 15cm to 35cm is between 20cm to 30cm. This behaviour may be considered to apply to other type of helical pile foundations in peat soil.

Interfacial area transport of bubbly flow in a small diameter pipe

International Nuclear Information System (INIS)

Hibiki, Takashi; Takamasa, Tomoji; Ishii, Mamoru

2001-01-01

In relation to the development of the interfacial area transport equation, this study focused on modeling of the interfacial area transport mechanism of vertical adiabatic air-water bubbly flows in a relatively small diameter pipe where the bubble size-to-pipe diameter ratio was relatively high and the radial motion of bubbles was restricted by the presence of the pipe wall. The sink term of the interfacial area concentration was modeled by considering wake entrainment as a possible bubble coalescence mechanism, whereas the source term was neglected by assuming negligibly small bubble breakup for low liquid velocity conditions based on visual observation. One-dimensional interfacial area transport equation with the derived sink term was evaluated by using five datasets of vertical adiabatic air-water bubbly flows measured in a 9.0 mm-diameter pipe (superficial gas velocity: 0.013-0.052 m/s, superficial liquid velocity: 0.58-1.0 m/s). The modeled interfacial area transport equation could reproduce the proper trend of the axial interfacial area transport and predict the measured interfacial area concentrations within an average relative deviation of ±11.1%. It was recognized that the present model would be promising for predicting the interfacial area transport of the examined bubbly flows. (author)

Comparison of Different Height–Diameter Modelling Techniques for Prediction of Site Productivity in Natural Uneven-Aged Pure Stands

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Guangshuang Duan

2018-01-01

Full Text Available Reliable estimates of forest site productivity are a central element of forest management. The model of height-diameter relationship of dominant trees using algebraic difference approach (ADA is a commonly used method to measure site productivity of natural uneven-aged stands. However, the existing models of this method do not recognize site type or sample plot specific variability in height curves; thus, it cannot be effectively used to estimate site type or sample plot-related site productivity for natural uneven-aged stands. Two primary subject-specific approaches, ADA with dummy variable (DV (ADA + DV and ADA with combination of dummy variable and nonlinear mixed-effects modelling (CM (ADA + CM, were proposed for height–diameter modelling. Height–diameter models developed with ADA, ADA + DV and ADA + CM were compared using data from 4161 observations on 349 permanent sample plots of four major natural uneven-aged pure stands (Spruce, Korean Larch, Mongolian Oak, and White Birch in northeastern China. It was found that models developed with ADA + CM provided the best performance, followed by the models with ADA + DV, and the models developed with ADA performed the worst. Random effects at the plot level were substantial, and their inclusion greatly improved the model’s accuracy. More importantly, the models developed with ADA + CM provide an effective method for quantifying site type- and sample plot-specific forest site productivity for uneven-aged pure stands.

Controlling liquid pool depth in VAR of a 21.6 cm diameter ingot of Alloy 718

Science.gov (United States)

Lopez, Felipe; Beaman, Joseph; Williamson, Rodney; Taleff, Eric; Watt, Trevor

It is believed that the final microstructure in vacuum arc remelted (VAR) ingots is strongly influenced by the molten metal pool profile. Thus, if the pool profile was properly controlled during the melt then defect-free microstructures would be obtained. The recent development of a reduced-order model of VAR solidification allowed the design of a pool depth controller to accomplish this task. The controller used a linear quadratic regulator and a Kalman filter to stabilize the melt pool solidification front under the effect of uncertain process dynamics and noisy measurements. Basic Axisymmetric Remelting (BAR), a high-fidelity VAR ingot model, was used in real time to provide pool depth measurements that were incorporated in the control loop. The controller was tested at Los Alamos National Laboratory in a 21.6 diameter Alloy 718 ingot. Details of the controller design will be presented, along with comparisons to experimentally-measured pool depths.

Description and evaluation of the Earth System Regional Climate Model (RegCM-ES)

Science.gov (United States)

Farneti, Riccardo; Sitz, Lina; Di Sante, Fabio; Fuentes-Franco, Ramon; Coppola, Erika; Mariotti, Laura; Reale, Marco; Sannino, Gianmaria; Barreiro, Marcelo; Nogherotto, Rita; Giuliani, Graziano; Graffino, Giorgio; Solidoro, Cosimo; Giorgi, Filippo

2017-04-01

The increasing availability of satellite remote sensing data, of high temporal frequency and spatial resolution, has provided a new and enhanced view of the global ocean and atmosphere, revealing strong air-sea coupling processes throughout the ocean basins. In order to obtain an accurate representation and better understanding of the climate system, its variability and change, the inclusion of all mechanisms of interaction among the different sub-components, at high temporal and spatial resolution, becomes ever more desirable. Recently, global coupled models have been able to progressively refine their horizontal resolution to attempt to resolve smaller-scale processes. However, regional coupled ocean-atmosphere models can achieve even finer resolutions and provide additional information on the mechanisms of air-sea interactions and feedbacks. Here we describe a new, state-of-the-art, Earth System Regional Climate Model (RegCM-ES). RegCM-ES presently includes the coupling between atmosphere, ocean, land surface and sea-ice components, as well as an hydrological and ocean biogeochemistry model. The regional coupled model has been implemented and tested over some of the COordinated Regional climate Downscaling Experiment (CORDEX) domains. RegCM-ES has shown improvements in the representation of precipitation and SST fields over the tested domains, as well as realistic representations of coupled air-sea processes and interactions. The RegCM-ES model, which can be easily implemented over any regional domain of interest, is open source making it suitable for usage by the large scientific community.

Future Projections of Air Temperature and Precipitation for the CORDEX-MENA Domain by Using RegCM4.3.5

Science.gov (United States)

Ozturk, Tugba; Turp, M. Tufan; Türkeş, Murat; Kurnaz, M. Levent

2015-04-01

In this study, the projected changes for the periods of 2016 - 2035, 2046 - 2065, and 2081 - 2100 in the seasonal averages of air temperature and precipitation variables with respect to the reference period of 1981 - 2000 were examined for the Middle East and North Africa region. In this context, Regional Climate Model (RegCM4.3.5) of ICTP (International Centre for Theoretical Physics) was run by using two different global climate models. MPI-ESM-MR global climate model of the Max Planck Institute for Meteorology and HadGEM2 of the Met Office Hadley Centre were dynamically downscaled to 50 km for the CORDEX-MENA domain. The projections were realized according to the RCP4.5 and the RCP8.5 emission scenarios of the IPCC (Intergovernmental Panel of Climate Change).

Effect of hole geometry and Electric-Discharge Machining (EDM) on airflow rates through small diameter holes in turbine blade material

Science.gov (United States)

Hippensteele, S. A.; Cochran, R. P.

1980-01-01

The effects of two design parameters, electrode diameter and hole angle, and two machine parameters, electrode current and current-on time, on air flow rates through small-diameter (0.257 to 0.462 mm) electric-discharge-machined holes were measured. The holes were machined individually in rows of 14 each through 1.6 mm thick IN-100 strips. The data showed linear increase in air flow rate with increases in electrode cross sectional area and current-on time and little change with changes in hole angle and electrode current. The average flow-rate deviation (from the mean flow rate for a given row) decreased linearly with electrode diameter and increased with hole angle. Burn time and finished hole diameter were also measured.

Cost of Czochralski wafers as a function of diameter

Science.gov (United States)

Leipold, M. H.; Radics, C.; Kachare, A.

1980-02-01

The impact of diameter in the range of 10 to 15 cm on the cost of wafers sliced from Czochralski ingots was analyzed. Increasing silicon waste and decreasing ingot cost with increasing ingot size were estimated along with projected costs. Results indicate a small but continuous decrease in sheet cost with increasing ingot size in this size range. Sheet costs including silicon are projected to be $50 to $60/sq m (1980 $) depending upon technique used.

Extraction of Trees Stem Diameters at Breast Height by Terrestrial Laser Sensor for Selective Cutting

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Yili ZHENG

2014-02-01

Full Text Available In order to assist the operators of the logging harvester automatically and quickly select the appropriate trees for selective cutting, using two-dimensional laser scanner and inertial measurement system, the two-dimensional cloud points of the trunks at breast-height are obtained for several trees. After projection, clustering, linear transformation and fitting for the point clouds data, the parameters of the breast-height-diameters and center locations of the trees are obtained. The calculation is implemented in MATLAB by Polak-Ribiere-Polyak (PRP conjugate gradient algorithm and the result is shown in VC++ environment. Using this method, absolute errors of the breast-height- diameters and center locations are 2.3 cm and (12.4, 11.4 cm respectively, and meet the requirements on the automatically selective cutting of the logging harvester.

Equations for predicting diameter, height, crown width, and leaf area of San Joaquin Valley street trees

Science.gov (United States)

P.J. Peper; E.G. McPherson; S.M. Mori

2001-01-01

Although the modeling of energy-use reduction, air pollution uptake, rainfall interception, and microclimate modification associated with urban trees depends on data relating diameter at breast height (dbh) , crown height, crown diameter, and leaf area to tree age or dbh, scant information is available for common municipal tree species . I n this study , tree height ,...

Treatment of ammonia in waste air using packed column coupling with chemical reaction

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Thepchai, R.

2007-05-01

Full Text Available Ammonia is a common chemical used in various industries. Emission of air contaminated with ammonia to the atmosphere without any treatment causes several effects on human health and environment.A high efficiency method for ammonia removal from waste air is then necessary. In this research, an absorption coupling with chemical reaction was investigated for ammonia removal from waste air using a packedcolumn. The packed column of 10 cm diameter and 200 cm height was packed with 1.4x1.4 cm Raschig rings. Three liquids including water, NaOCl and H2SO4 solution were used as an absorbent for the investigation.The objectives of this research were to determine a suitable absorbent and the optimum condition for ammonia removal from waste air. The packed column was operated at room temperature and atmosphericpressure. The tested conditions were as follows: the gas to liquid ratio (G:L ratio was 35-90 m3 gas/m3 liquid, the inlet concentration of ammonia was 150-500 ppm and the air flow rate was 18 m3/h. The results showedthat the ammonia removal efficiency depends on type of the absorbent and the operating condition. The efficiencies increased with decreasing of G:L ratio and with increasing absorbent concentration. They were70%, 80-92%, and 95-100% for pure water, sodium hypochlorite solution and sulphuric acid solution, respectively. The efficiency decreased with time when water was used as an absorbent while it was almostconstant when NaOCl and H2SO4 solution were applied. The ammonia removal efficiency when using H2SO4 as the absorbent was not dependent on G:L ratio and inlet ammonia concentration, in the range used in thisinvestigation. Since H2SO4 solution gave the highest removal efficiency and can reduce ammonia concentration in waste air to levels which meet the TLV-TWA standard, it is recommended as an absorbent solution forammonia removal from waste air.

Generation of longitudinally polarized terahertz pulses with field amplitudes exceeding 2 kV/cm

Science.gov (United States)

Cliffe, M. J.; Rodak, A.; Graham, D. M.; Jamison, S. P.

2014-11-01

We demonstrate the generation of near-single cycle longitudinally polarized terahertz radiation using a large-area radially biased photoconductive antenna with a longitudinal field amplitude in excess of 2 kV/cm. The 76 mm diameter antenna was photo-excited by a 0.5 mJ amplified near-infrared femtosecond laser system and biased with a voltage of up to 100 kV applied over concentric electrodes. Amplitudes for both the transverse and longitudinal field components of the source were measured using a calibrated electro-optic detection scheme. By tightly focusing the radiation emitted from the photoconductive antenna, we obtained a maximum longitudinal field amplitude of 2.22 kV/cm with an applied bias field of 38.5 kV/cm.

Woodland: dynamics of average diameters of coniferous tree stands of the principal forest types

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R. A. Ziganshin

2016-08-01

Full Text Available The analysis of age dynamics of average diameters of deciduous tree stands of different forest types at Highland Khamar-Daban (natural woodland in South-East Baikal Lake region has been done. The aggregate data of average tree, the analysis of age dynamics of average diameters of a deciduous tree stands of stand diameters by age classes, as well as tree stand current periodic and overall average increment are presented and discussed in the paper. Forest management appraisal is done. The most representative forest types have been selected to be analyzed. There were nine of them including three Siberian stone pine Pinus sibirica Du Tour stands, three Siberian fir Abies sibirica Ledeb. stands, one Siberian spruce Picea obovata Ledeb. stand, and two dwarf Siberian pine Pinus pumila (Pallas Regel stands. The whole high-altitude range of mountain taiga has been evaluated. Mathematical and statistic indicators have been calculated for every forest type. Stone pine stands are the largest. Dynamics of mean diameters of forest stands have been examined by dominant species for every forest type. Quite a number of interesting facts have been elicited. Generally, all species have maximal values of periodic annual increment that is typical for young stands, but further decrease of increment is going on differently and connects to the different lifetime of wood species. It is curious that annual increment of the dwarf Siberian pine stands almost does not decrease with aging. As for mean annual increment, it is more stable than periodic annual increment. From the fifth age class (age of stand approaching maturity mean annual increment of cedar stands varies from 0.20 to 0.24 cm per year; from 0.12–0.15 to 0.18–0.21 cm per year – in fir stands; from 0.18 to 0.24 cm per year – in spruce stands; and from 0.02–0.03 to 0.05–0.06 cm per year – in draft pine stands. Mean annual increment of dwarf Siberian pine increases with aging and increment of other

Spatial variability of hailfalls in France: an analysis of air mass retro-trajectories

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Hermida, Lucía; Merino, Andrés; Sánchez, José Luis; Berthet, Claude; Dessens, Jean; López, Laura; Fernández-González, Sergio; Gascón, Estíbaliz; García-Ortega, Eduardo

2014-05-01

Hail is the main meteorological risk in south-west France, with the strongest hailfalls being concentrated in just a few days. Specifically, this phenomenon occurs most often and with the greatest severity in the Midi-Pyrénées area. Previous studies have revealed the high spatial variability of hailfall in this part of France, even leading to different characteristics being recorded on hailpads that were relatively close together. For this reason, an analysis of the air mass trajectories was carried out at ground level and at altitude, which subsequently led to the formation of the hail recorded by these hailpads. It is already known that in the study zone, the trajectories of the storms usually stretch for long distances and are oriented towards the east, leading to hailstones with diameters in excess of 3 cm, and without any change in direction above 3 km. We analysed different days with hail precipitation where there was at least one stone with a diameter of 3 cm or larger. Using the simulations from these days, an analysis of the backward trajectories of the air masses was carried out. We used the HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) to determine the origin of the air masses, and tracked them toward each of the hailpads that were hit during the day studied. The height of the final points was the height of the impacted hailpads. Similarly, the backward trajectories for different heights were also established. Finally, the results show how storms that affect neighbouring hailpads come from very different air masses; and provide a deeper understanding of the high variability that affects the characteristics of hailfalls. Acknowledgements The authors would like to thank the Regional Government of Castile-León for its financial support through the project LE220A11-2. This study was supported by the following grants: GRANIMETRO (CGL2010-15930); MICROMETEO (IPT-310000-2010-22).

Ultrasonographic findings of papillary carcinoma of the thyroid according to the size: Especially less than 0.5 cm

Energy Technology Data Exchange (ETDEWEB)

Park, So Yung; Kim, Yun Min; Lee, Hyun Bok; Cho, Nam Soo [Dept. of Diagonostic Radiology, Samsung Medical Center, Seoul (Korea, Republic of); Yoon, Joon [Dept. of Radiologic Technology, Dongnam Health College, (Korea, Republic of)

2013-06-15

The Korean Thyroid Association recommends fine-needle aspiration biopsy (FNAB) for nodules more than 0.5 cm in diameter. But nodules, smaller than 0.5 cm have been found in papillary carcinomas of the thyroid (PTC) at the health promotion center at SMC. We wanted to evaluate the ultrasonographic findings according to size of nodule in proven PTCs by FNAB, especially less than 0.5 cm. All nodules were classified into three groups by their longest diameter : less than 0.5 cm, more than 0.5 cm but less than 1 cm, and more than 1 cm. Sonographic findings suggesting malignancy were analyzed according to their size groups. Of 288 malignant nodules, 21.5 % (62/288) were less than 0.5 cm , 54.9 % (158/288) were more than 0.5 cm but less than 1 cm, 23.6 % (68/288) exceeded 1 cm. A taller-than-wide shape was observed in 90.3 % (56/62) of nodules less than 0.5 cm, and 48.5 % (33/68) of nodules exceeding 1 cm (p<0.001). There were no well-defined smooth nodules among nodules less than 0.5 cm, and spiculated or irregular margin nodules increased as the size increased (p=0.024). Nodules of size less than 0.5 cm did not showed hyper or isoechogenicity. Hypoechogenicity was greater than the marked hypoechogenicity in each group (p=0.034). Micro- or macro-calcifications were not founded in 77.4 % (48/62) of the nodule group sized less than 0.5 cm. From the small size of the group, micro- or macrocalcifications were observed 21.0 % (13/62), 48.1 % (76/158), 64.7 % (44/68), so the number of nodules containing micro- or macro-calcification increased as size increased (p<0.001). PTCs less than 0.5 cm in size on ultrasonography had taller than-wide shape, spiculated or irregular and ill-defined margins, and exhibited hypo and markedly hypoechogenicity, but microor macro-calcifications were not common. These ultrasonographic features of nodules less than 0.5 cm can be useful in reporting and guiding FNABs or follow-up exams.

Sterilization efficacy of ultraviolet irradiation on microbial aerosols under dynamic airflow by experimental air conditioning systems

International Nuclear Information System (INIS)

Nakamura, Hiroshi

1987-01-01

In order to know the sterilization efficacy of ultraviolet irradiation on microbial aerosols, the size and the weight of the aerosol particles were evaluated, and these were irradiated under dynamic air flow created by an experimental air conditioning system. The experimental apparatus consisted of a high efficiency particulate air (HEPA) filter, an aerosol generator, spiral UV lamps placed around a quart glass tube, an Andersen air sampler and a vacuum pump. They were connected serially by stainless steel ducts (85 mm in diameter, 8 m in length). Six types of microbial aerosols generated from an ultrasonic nebulizer were irradiated by UV rays (wavelength 254 nm, mean density 9400 μW/cm 2 ). Their irradiation time ranged from 1.0 to 0.0625 seconds. The microbial aerosols were collected onto the trypticase soy agar (TSA) medium in the Andersen air sampler. After incubation, the number of colony forming units (CFU) were counted, and converted to particle counts. The diameter of microbial aerosol particles calculated by their log normal distribution were found to match the diameter of a single bacteria cell measured by a microscope. The sterilization efficacy of UV in standard airflow conditions (0.5 sec. irradiation) were found to be over 99.5 % in Staphylococcus aureus, Staphylococcus epidermidis, Serratia marcescens, Bacillus subtilis (vegetative cell) and Bacillus subtilis (spore) and 67 % in Aspergillus niger (conidium). In A. niger, which was the most resistant microbe to UV irradiation, the efficacy rose up to 79 % when irradiated for 1.0 sec., and it was observed that the growth speed of the colonies was slower than that of the controls. It was thought that UV rays caused some damage to the proliferation of A. niger cells. (author)

Aerodynamic effect of a honeycomb rotor tip shroud on a 50.8-centimeter-tip-diameter core turbine

Science.gov (United States)

Moffitt, T. P.; Whitney, W. J.

1983-01-01

A 50.8-cm-tip-diameter turbine equipped with a rotor tip shroud of hexagonal cell (or honeycomb) cross section has been tested in warm air (416 K) for a range of shroud coolant to primary flow rates. Test results were also obtained for the same turbine operated with a solid shroud for comparison. The results showed that the combined effect of the honeycomb shroud and the coolant flow was to cause a reduction of 2.8 points in efficiency at design speed, pressure ratio, and coolant flow rate. With the coolant system inactivated, the honeycomb shroud caused a decrease in efficiency of 2.3 points. These results and those obtained from a small reference turbine indicate that the dominant factor governing honeycomb tip shroud loss is the ratio of honeycomb depth to blade span. The loss results of the two shrouds could be correlated on this basis. The same honeycomb and coolant effects are expected to occur for the hot (2200 K) version of this turbine.

Compact modular BWR (CM-BWR)

International Nuclear Information System (INIS)

Fennern, Larry; Boardman, Charles; Carroll, Douglas G.; Hida, Takahiko

2003-01-01

A preliminary assessment has shown that a small 350 MWe BWR reactor can be placed within a close fitting steel containment vessel that is 7.1 meters inside diameter. This allows the technology and manufacturing capability currently used to fabricate large ABWR reactor vessels to be used to provide a factory fabricated containment vessel for a 350 MWe BWR. When a close fitted steel containment is combined with a passive closed loop isolation condenser system and a natural circulating reactor system that contains a large water inventory, primary system leaks cannot uncover the core. This eliminates many of the safety systems needed in response to a LOCA that are common to large, conventional plant designs including. Emergency Core Flooding, Automatic Depressurization System, Active Residual Heat Removal, Safety Related Auxiliary Cooling, Safety Related Diesel Generators, Hydrogen Re-Combiners, Ex-vessel Core Retention and Cooling. By fabricating the containment in a factory and eliminating most of the conventional safety systems, the construction schedule is shortened and the capital cost reduced to levels that would not otherwise be possible for a relatively small modular BWR. This makes the CM-BWR a candidate for applications where smaller incremental power additions are desired relative to a large ALWR or where the local infrastructure is not able to accommodate a conventional ALWR plant rated at 1350 MWe or more. This paper presents a preliminary design description of a Compact Modular BWR (CM-BWR) whose design features dramatically reduce the size and cost of the reactor building and associated safety systems. (author)

Experimental Line List of Water Vapor Absorption Lines in the Spectral Ranges 1850 - 2280 CM-1 and 2390-4000 CM-1

Science.gov (United States)

Loos, Joep; Birk, Manfred; Wagner, Georg

2017-06-01

A new experimental line parameter list of water vapor absorption lines in the spectral ranges 1850 - 2280 cm-1 and 2390 - 4000 cm-1 is presented. The line list is based on the analysis of several transmittance spectra measured using a Bruker IFS 125 HR high resolution Fourier transform spectrometer. A total of 54 measurements of pure water and water/air-mixtures at 296 K as well as water/air-mixtures at high and low temperatures were performed. A multispectrum fitting approach was used applying a quadratic speed-dependent hard collision line shape model in the Hartmann-Tran implementation extended to account for line mixing in the Rosenkranz approximation in order to retrieve line positions, intensities, self- and air-broadening parameters, their speed-dependence, self- and air-shifts as well as line mixing and in some cases collisional narrowing parameters. Additionally, temperature dependence parameters for widths, shifts and in a few cases line mixing were retrieved. For every parameter an extensive error estimation calculation was performed identifying and specifying systematic error sources. The resulting parameters are compared to the databases HITRAN12 as well as experimental values. For intensities, a detailed comparison to results of recent ab initio calculations performed at University College London was done showing an agreement within 2 % for a majority of the data. However, for some bands there are systematic deviations attributed to ab initio calculation errors. .H. Ngo et al. JQSRT 129, 89-100 (2013) doi:10.1016/j.jqsrt.2013.05.034; JQSRT 134, 105 (2014) doi:10.1016/j.jqsrt.2013.10.016. H. Tran et al. JQSRT 129, 199-203 (2013) doi:10.1016/j.jqsrt.2013.06.015; JQSRT 134, 104 (2014) doi:10.1016/j.jqsrt.2013.10.015. L.S. Rothman et al. JQSRT 130, 4-50 (2013) doi:10.1016/j.jqsrt.2013.07.002. N. Jacquinet-Husson et al. JMS 112, 2395-2445 (2016) doi:10.1016/j.jms.2016.06.007.

DEVELOPMENT OF A NINE INCH DIAMETER, MACH 5.5, MONORAIL, ROCKET SLED.

Science.gov (United States)

A nine inch diameter monorail rocket sled was designed, fabricated and tested at Holloman Air Force Base. The vehicle was designed to allow easy...replacement of appendages which were subject to severe aerodynamic heating and/or high wear rates. The monorail vehicle as described was shown to be

US Intergroup Anal Carcinoma Trial: Tumor Diameter Predicts for Colostomy

Science.gov (United States)

Ajani, Jaffer A.; Winter, Kathryn A.; Gunderson, Leonard L.; Pedersen, John; Benson, Al B.; Thomas, Charles R.; Mayer, Robert J.; Haddock, Michael G.; Rich, Tyvin A.; Willett, Christopher G.

2009-01-01

Purpose The US Gastrointestinal Intergroup Radiation Therapy Oncology Group 98-11 anal carcinoma trial showed that cisplatin-based concurrent chemoradiotherapy resulted in a significantly higher rate of colostomy compared with mitomycin-based therapy. Established prognostic variables for patients with anal carcinoma include tumor diameter, clinical nodal status, and sex, but pretreatment variables that would predict the likelihood of colostomy are unknown. Methods A secondary analysis was performed by combining patients in the two treatment arms to evaluate whether new predictive and prognostic variables would emerge. Univariate and multivariate analyses were carried out to correlate overall survival (OS), disease-free survival, and time to colostomy (TTC) with pretreatment and treatment variables. Results Of 682 patients enrolled, 644 patients were assessable and analyzed. In the multivariate analysis, tumor-related prognosticators for poorer OS included node-positive cancer (P ≤ .0001), large (> 5 cm) tumor diameter (P = .01), and male sex (P = .016). In the treatment-related categories, cisplatin-based therapy was statistically significantly associated with a higher rate of colostomy (P = .03) than was mitomycin-based therapy. In the pretreatment variables category, only large tumor diameter independently predicted for TTC (P = .008). Similarly, the cumulative 5-year colostomy rate was statistically significantly higher for large tumor diameter than for small tumor diameter (Gray's test; P = .0074). Clinical nodal status and sex were not predictive of TTC. Conclusion The combined analysis of the two arms of RTOG 98-11, representing the largest prospective database, reveals that tumor diameter (irrespective of the nodal status) is the only independent pretreatment variable that predicts TTC and 5-year colostomy rate in patients with anal carcinoma. PMID:19139424

Rancang Bangun dan Studi Eksperimen Alat Penukar Panas untuk Memanfaatkan Energi Refrigerant Keluar Kompresor AC sebagai Pemanas Air pada ST/D=8 dengan Variasi Volume Air

Directory of Open Access Journals (Sweden)

Fajri Chairbowo

2017-01-01

Full Text Available Abstrak­- Kebutuhan masyarakat terhadap air hangat semakin meningkat. Hal itu disebabkan air hangat mempunyai berbagai manfaat. Air hangat efektif dalam melarutkan lemak ataupun sabun, serta air hangat dapat melancarkan peredaran darah manusia ketika digunakan. Demi efisiensi dalam penggunaan energi, penelitian yang dilakukan tentang pemanfaatan panas buang dari sistem refrigerasi.. Sebelum panas dibuang ke lingkungan, water heater ditambahkan oleh penulis ke sistem refrigerasi yang peletakkannya sesudah proses kompresi. Dimana water heater akan mengambil kalor dari refrigeran pemanas yang melintas sesudah dari kompresor. Sistem refrigerasi yang digunakan mempunyai daya  1 HP (746 Watt. Dalam penelitian ini sudah ditetapkan diameter tube dari water heater adalah 1 cm dengan jarak transversal setiap tube 8 cm, fluida yang mengalir di dalam tube adalah R-22 dan fluida diam yang berada di dalam tangki adalah air. Langkah awal dari penelitian ini  adalah melakukan pengujian  sistem AC split untuk mendapatkan data-data yang dibutuhkan dalam perancangan water heater. Tahap selanjutnya adalah studi numerik dimana studi numerik dilakukan secara dua dimensi dengan kondisi steady, incompressible, dan laminar dengan prinsip Computational Fluid Dynamics (CFD, menggunakan perangkat lunak GAMBIT 2.4.6 untuk tahap pembuatan domain dan disimulasikan dengan perangkat lunak FLUENT 6.3.26. Tahap terakhir adalah eksperimen yang bertujuan untuk mengetahui water heater yang dibuat sesuai dengan rancangan penulis. Kemudian water heater yang sudah dibuat, dipasang ke sistem AC split. Pada tahap eksperimen, penulis melakukan variasi terhadap volume air di tangki, yaitu 75 liter, 85 liter dan 100 liter. Hasil dari simulasi numerik menunjukkan fenomena perpindahan panas pada water heater, yang berupa kontur temperatur, kontur kecepatan dan velocity vector dalam bentuk dua dimensi tampak samping water heater. Hasil dari studi eksperimen ini menunjukkan nilai

Crown-Stump Diameter Model for Parkia biglobosa Benth. Species in Makurdi, Benue State, Nigeria

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O. Chukwu

2017-07-01

Full Text Available The crown of tree is the centre of physiological activity which gives an indication of the potential photosynthetic capacity on a tree. Though, its measurement remains a challenge in forest inventory task. The ability to predict crown diameter from stump diameter provides an effective technique of obtaining its estimate. This helps in detecting the excessive tree felling than actual requirements and wildlife suitability.The main objective of this study was to develop and test crown diameter prediction models for silvicultural management of naturally grown Parkia biglobosa within the University of Agriculture, Makurdi. Nine 100 m x 100 m temporary sample plots were established using simple random sampling method. Crown diameter and stump diameter were measured in all living P. biglobosa trees with stump diameter ≥10.0 cm. Least square method was used to convert the counted stumps into harvested crown dimension. Three linear and three non-linear models using stump diameter as the exploratory variable were developed and evaluated using the adjusted coefficient of determination (Adj.R2, standard error of estimate (SEE, prediction error sum of squares (PRESS and Akaike information criterion (AIC. The crown-stump diameter relationship was best described by the double logarithmic function with .The result showed that Crown diameter estimation was feasible even when the only information available is stump diameter.The resulting equation was tested for validation with independent data obtained from additional plots and was found to be desirable for estimating the crown diameter for Parkia biglobosa in Makurdi, Benue State, Nigeria.

TEKNIK PENGATURAN AIR PADA INTENSIFIKASI PADI AEROB TERKENDALI-BERBASIS ORGANIK (IPAT-BO UNTUK MENINGKATKAN POPULASI RHIZOBACTERIA, EFISIENSI PENGGUNAAN AIR, PERAKARAN TANAMAN, DAN HASIL TANAMAN PADI

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Hingdri -

2013-03-01

Full Text Available Teknik pengaturan air pada budidaya tanaman padi melalui Intensifikasi Padi Aerob Terkendali-Berbasis Organik (IPAT-BO perlu dilakukan untuk meningkatkan efisiensi penggunaan air. Penelitian ini bertujuan untuk mengtahui aktivitas rhizobacteria, tingkat efisiensi penggunaan air, perkaran tanaman, dan hasil tanaman pada berbagai teknik pengaturan air.Penelitian dilaksanakan di lahan percobaan Fakultas Pertanian Universitas Winaya Mukti, Tanjungsari pada inceptisol pada skala pot plastik. Rancangan percobaan yang digunakan adalah Rancangan Acak Kelompok (RAK faktor tunggal dengan 16 perlakuan dan diulang tiga kali, yaitu terdiri dari kombinasi antara perlakuan air dan empat varietas. Perlakuan air: tinggi muka air + 5cm, 0 cm, – 5 cm dan  – 10 cm. Empat varietas: Ciherang, Sintanur, Inpari 13 dan Fatmawati..Hasil penelitian menunjukkan terdapat pengaruhnyata terhadap populasi Rhizobacteria, perkembangan akar, dan hasil tanaman. Perlakuan tinggi muka air – 10 cm varietas Fatmawati memberikan hasil tertinggi pada volume akar 186,67 ml, populasi bakteri Azotobacter sp. (1,43 x 1010 CFU g-1, bakteri pelarut fosfat (6,07 x 108 CFU g-1, hasil tanaman tertinggi 95,9 g rumpun-1 setara dengan 9,14 ton ha-1 serta meningkatkan efisiensi penggunaan air 47,1 % dibandingkan dengan pengenangan 5 cm.Kata kunci:  Teknik pengaturan air, efisiensi penggunaan air, IPAT-BO, populasi rhizobakteria

Advanced-technology 30-cm-diameter mercury ion thruster

Science.gov (United States)

Beattie, J. R.; Kami, S.

1982-01-01

An advanced-technology mercury ion thruster designed for operation at high thrust and high thrust-to-power ratio is described. The laboratory-model thruster employs a highly efficient discharge-chamber design that uses high-field-strength samarium-cobalt magnets arranged in a ring-cusp configuration. Ion extraction is achieved using an advanced three-grid ion-optics assembly which utilizes flexible mounts for supporting the screen, accel, and decel electrodes. Performance results are presented for operation at beam currents in the range from 1 to 5 A. The baseline specific discharge power is shown to be about 125 eV/ion, and the acceptable range of net-to-total accelerating-voltage ratio is shown to be in the range of 0.2-0.8 for beam currents in the range of 1-5 A.

Multimodal quantitation of the effects of endovascular therapy for vasospasm on cerebral blood flow, transcranial doppler ultrasonographic velocities, and cerebral artery diameters.

Science.gov (United States)

Oskouian, Rod J; Martin, Neil A; Lee, Jae Hong; Glenn, Thomas C; Guthrie, Donald; Gonzalez, Nestor R; Afari, Arash; Viñuela, Fernando

2002-07-01

The goal of this study was to quantify the effects of endovascular therapy on vasospastic cerebral vessels. We reviewed the medical records for 387 patients with ruptured intracranial aneurysms who were treated at a single institution (University of California, Los Angeles) between May 1, 1993, and March 31, 2001. Patients who developed cerebral vasospasm and underwent cerebral arteriographic, transcranial Doppler ultrasonographic, and cerebral blood flow (CBF) studies before and after endovascular therapy for cerebral arterial spasm (vasospasm) were included in this study. Forty-five patients fulfilled the aforementioned criteria and were treated with either papaverine infusion, papaverine infusion with angioplasty, or angioplasty alone. After balloon angioplasty (12 patients), CBF increased from 27.8 +/- 2.8 ml/100 g/min to 28.4 +/- 3.0 ml/100 g/min (P = 0.87); the middle cerebral artery blood flow velocity was 1 57.6 +/- 9.4 cm/s and decreased to 76.3 +/- 9.3 cm/s (P < 0.05), with a mean increase in cerebral artery diameters of 24.4%. Papaverine infusion (20 patients) transiently increased the CBF from 27.5 +/- 2.1 ml/100 g/min to 38.7 +/- 2.8 ml/100 g/min (P < 0.05) and decreased the middle cerebral artery blood flow velocity from 109.9 +/- 9.1 cm/s to 82.8 +/- 8.6 cm/s (P < 0.05). There was a mean increase in vessel diameters of 30.1% after papaverine infusion. Combined treatment (13 patients) significantly increased the CBF from 33.3 +/- 3.2 ml/100 g/min to 41.7 +/- 2.8 ml/100 g/min (P< 0.05) and decreased the transcranial Doppler velocities from 148.9 +/- 12.7 cm/s to 111.4 +/- 10.6 cm/s (P < 0.05), with a mean increase in vessel diameters of 42.2%. Balloon angioplasty increased proximal vessel diameters, whereas papaverine treatment effectively dilated distal cerebral vessels. In our small series, we observed no correlation between early clinical improvement or clinical outcomes and any of our quantitative or physiological data (CBF, transcranial Doppler

Database for Pressure Tube Diameter and Operation Data of Wolsong NPP

International Nuclear Information System (INIS)

Jung, Jong Yeob; Kim, W. Y.; Bae, J. H.; Park, J. H.

2010-12-01

Pressure tube of CANDU reactor which is a long cylindrical shape of its diameter about 10 cm and length of about 6m, can be expanded toward both radial and axial directions due to irradiation under the high pressure and temperature condition. As the irradiation period increases, the radial expansion due to creep of the pressure tube increases. The radial expansion of the pressure tube comes out the reduction of the coolability and it results in the power deration. The objectives of the current work is to establish the database for the measured diametral data of pressure tube and operational data from Wolsong NPP as a preliminary work of developing the prediction model for pressure tube diameter. In order to develop the database, measured data for total 86 channels were collected from Wolsong NPP 1, 2, 3 and 4 and analyzed. Based on the provided data, the operational conditions such as an axial temperature and a pressure of the channel and neutron fluxes were derived. All data were analysed to derive the correlation between the pressure tube diameter and the other operational parameters

High-Speed Measurement of the Internal Diameter of Tubes: A Comparison of Methods

DEFF Research Database (Denmark)

Gundtoft, Hans Erik; Agerup, C.C.; Nielsen, N.

1974-01-01

The authors have compared various methods of tube measurement and have made the striking conclusion that the continuous measurement of the internal diameter of precision tubes with an air gauge is often useless in practice. The methods selected for experiment were all contactless and so included...

A biokinetic model of inhaled Cm compounds in dogs: Application to human exposure data

International Nuclear Information System (INIS)

Guilmette, R.A.; Mewhinney, J.A.

1989-01-01

Curium isotopes are major by-products in irradiated nuclear reactor fuel and comprise a significant fraction of the alpha-emitting radionuclide inventory. Although little use is currently being made of purified Cm sources, such usage is possible if reprocessing of spent fuel becomes feasible. Because little information is available on the biokinetics and dosimetry of inhaled Cm compounds, a study was conducted in which adult beagle dogs received a single inhalation exposure to either a monodisperse aerosol of 244Cm2O3 (1.4 micron activity median aerodynamic diameter [AMAD]; sigma g = 1.16) or a polydisperse aerosol of 244Cm (NO3)3 (1.1 micron AMAD; sigma g = 1.74). At times ranging from 4 h to 2 y after exposure, animals were sacrificed and their tissues analyzed for Cm content. The data describing the uptake and retention of 244Cm in the different organs and tissues and the measured rates of excretion of these dogs formed the basis on which a biokinetic model of Cm metabolism was constructed. This Cm model was based on a previously published model of the biokinetics of 241Am that was shown to be applicable to data from human cases of inhalation exposure to 241Am aerosols. This Cm model was found to be adequate to describe the biological distribution of Cm in dogs and was also applied to the sparse data from humans. Reasonable agreement was found between the model predictions for lung retention of Cm and for urinary excretion patterns in humans

Regional Models of Diameter as a Function of Individual Tree Attributes, Climate and Site Characteristics for Six Major Tree Species in Alberta, Canada

Directory of Open Access Journals (Sweden)

Dan A. MacIsaac

2011-09-01

Full Text Available We investigated the relationship of stem diameter to tree, site and stand characteristics for six major tree species (trembling aspen, white birch, balsam fir, lodgepole pine, black spruce, and white spruce in Alberta (Canada with data from Alberta Sustainable Resource Development Permanent Sample Plots. Using non-linear mixed effects modeling techniques, we developed models to estimate diameter at breast height using height, crown and stand attributes. Mixed effects models (with plot as subject using height, crown area, and basal area of the larger trees explained on average 95% of the variation in diameter at breast height across the six species with a root mean square error of 2.0 cm (13.4% of mean diameter. Fixed effects models (without plot as subject including the Natural Sub-Region (NSR information explained on average 90% of the variation in diameter at breast height across the six species with a root mean square error equal to 2.8 cm (17.9% of mean diameter. Selected climate variables provided similar results to models with NSR information. The inclusion of nutrient regime and moisture regime did not significantly improve the predictive ability of these models.

Generation of longitudinally polarized terahertz pulses with field amplitudes exceeding 2 kV/cm

Energy Technology Data Exchange (ETDEWEB)

Cliffe, M. J., E-mail: Matthew.Cliffe@manchester.ac.uk; Rodak, A.; Graham, D. M. [School of Physics and Astronomy and the Photon Science Institute, The University of Manchester, Manchester M13 9PL (United Kingdom); The Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Daresbury, Warrington WA4 4AD (United Kingdom); Jamison, S. P. [The Cockcroft Institute, Sci-Tech Daresbury, Keckwick Lane, Daresbury, Warrington WA4 4AD (United Kingdom); Accelerator Science and Technology Centre, Science and Technology Facilities Council, Darebsury Laboratory, Keckwick Lane, Daresbury, Warrington WA4 4AD (United Kingdom)

2014-11-10

We demonstrate the generation of near-single cycle longitudinally polarized terahertz radiation using a large-area radially biased photoconductive antenna with a longitudinal field amplitude in excess of 2 kV/cm. The 76 mm diameter antenna was photo-excited by a 0.5 mJ amplified near-infrared femtosecond laser system and biased with a voltage of up to 100 kV applied over concentric electrodes. Amplitudes for both the transverse and longitudinal field components of the source were measured using a calibrated electro-optic detection scheme. By tightly focusing the radiation emitted from the photoconductive antenna, we obtained a maximum longitudinal field amplitude of 2.22 kV/cm with an applied bias field of 38.5 kV/cm.

Generation of longitudinally polarized terahertz pulses with field amplitudes exceeding 2 kV/cm

International Nuclear Information System (INIS)

Cliffe, M. J.; Rodak, A.; Graham, D. M.; Jamison, S. P.

2014-01-01

We demonstrate the generation of near-single cycle longitudinally polarized terahertz radiation using a large-area radially biased photoconductive antenna with a longitudinal field amplitude in excess of 2 kV/cm. The 76 mm diameter antenna was photo-excited by a 0.5 mJ amplified near-infrared femtosecond laser system and biased with a voltage of up to 100 kV applied over concentric electrodes. Amplitudes for both the transverse and longitudinal field components of the source were measured using a calibrated electro-optic detection scheme. By tightly focusing the radiation emitted from the photoconductive antenna, we obtained a maximum longitudinal field amplitude of 2.22 kV/cm with an applied bias field of 38.5 kV/cm

Pratt & Whitney aircraft nuclear J-8 turbojet engine performance variation with radiator diameter

International Nuclear Information System (INIS)

Larson, John W.

1960-01-01

The variation of engine performance with liquid metal radiator diameter and flight altitude has been estimated for both the 1600F NaK and 1800F NaK radiators at Mach 0.6 and hot day atmospheric conditions. The net thrust, air flow and reactor power is presented in 3 figures for the Pratt & Whitney Aircraft J-58 engine with the 1600F NaK radiator. The net thrust, air flow and reactor power for the 1800F NaK radiator are also presented in figures.

Failure Diameter Resolution Study

Energy Technology Data Exchange (ETDEWEB)

Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-12-19

Previously the SURFplus reactive burn model was calibrated for the TATB based explosive PBX 9502. The calibration was based on fitting Pop plot data, the failure diameter and the limiting detonation speed, and curvature effect data for small curvature. The model failure diameter is determined utilizing 2-D simulations of an unconfined rate stick to find the minimum diameter for which a detonation wave propagates. Here we examine the effect of mesh resolution on an unconfined rate stick with a diameter (10mm) slightly greater than the measured failure diameter (8 to 9 mm).

The lasting effect of limonene-induced particle formation on air quality in a genuine indoor environment.

Science.gov (United States)

Rösch, Carolin; Wissenbach, Dirk K; von Bergen, Martin; Franck, Ulrich; Wendisch, Manfred; Schlink, Uwe

2015-09-01

Atmospheric ozone-terpene reactions, which form secondary organic aerosol (SOA) particles, can affect indoor air quality when outdoor air mixes with indoor air during ventilation. This study, conducted in Leipzig, Germany, focused on limonene-induced particle formation in a genuine indoor environment (24 m(3)). Particle number, limonene and ozone concentrations were monitored during the whole experimental period. After manual ventilation for 30 min, during which indoor ozone levels reached up to 22.7 ppb, limonene was introduced into the room at concentrations of approximately 180 to 250 μg m(-3). We observed strong particle formation and growth within a diameter range of 9 to 50 nm under real-room conditions. Larger particles with diameters above 100 nm were less affected by limonene introduction. The total particle number concentrations (TPNCs) after limonene introduction clearly exceed outdoor values by a factor of 4.5 to 41 reaching maximum concentrations of up to 267,000 particles cm(-3). The formation strength was influenced by background particles, which attenuated the formation of new SOA with increasing concentration, and by ozone levels, an increase of which by 10 ppb will result in a six times higher TPNC. This study emphasizes indoor environments to be preferred locations for particle formation and growth after ventilation events. As a consequence, SOA formation can produce significantly higher amounts of particles than transported by ventilation into the indoor air.

Optimization of laser-induced breakdown spectroscopy for coal powder analysis with different particle flow diameters

Energy Technology Data Exchange (ETDEWEB)

Yao, Shunchun, E-mail: epscyao@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); State Key Laboratory of Pulsed Power Laser Technology, Electronic Engineering Institute, Hefei 230037 (China); Xu, Jialong; Dong, Xuan; Zhang, Bo; Zheng, Jianping [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China); Lu, Jidong, E-mail: jdlu@scut.edu.cn [School of Electric Power, South China University of Technology, Guangzhou, Guangdong 510640 (China)

2015-08-01

The on-line measurement of coal is extremely useful for emission control and combustion process optimization in coal-fired plant. Laser-induced breakdown spectroscopy was employed to directly analyze coal particle flow. A set of tapered tubes were proposed for beam-focusing the coal particle flow to different diameters. For optimizing the measurement of coal particle flow, the characteristics of laser-induced plasma, including optical breakdown, the relative standard deviation of repeated measurement, partial breakdown spectra ratio and line intensity, were carefully analyzed. The comparison of the plasma characteristics among coal particle flow with different diameters showed that air breakdown and the random change in plasma position relative to the collection optics could significantly influence on the line intensity and the reproducibility of measurement. It is demonstrated that the tapered tube with a diameter of 5.5 mm was particularly useful to enrich the coal particles in laser focus spot as well as to reduce the influence of air breakdown and random changes of plasma in the experiment. - Highlights: • Tapered tube was designed for beam-focusing the coal particle flow as well as enriching the particles in laser focus spot. • The characteristics of laser-induced plasma of coal particle flow were investigated carefully. • An appropriate diameter of coal particle flow was proven to benefit for improving the performance of LIBS measurement.

Small fan assisted air conditioner for thermal comfort and energy saving in Thailand

International Nuclear Information System (INIS)

Atthajariyakul, Surat; Lertsatittanakorn, Charoenporn

2008-01-01

From the fact that Thai people have a tolerance to high air temperature and are accustomed to high air movement from electric fans in non-air conditioned space, this paper proposes the use of small fan assisted air conditioners for human thermal comfort and energy saving in Thailand. In the study, a total 15 students were tested in a 2.5 x 3.5 x 2.5 m 3 test room equipped with a 12,000 Btu/h split type air conditioner. During the tests, the room air temperature was varied from 25, 26, 27 and 28 deg. C every 1 h. A small fan with 15 cm diameter was placed in front of each subject. In each hour, the small fan was varied to supply a small area with velocity from 0.2, 0.5, 1, 1.5 and 2 m/s. In each condition, the subjects were asked to vote for their thermal sensation. The results showed that the temperature set point could be increased up to 28 deg. C when a small fan was used to supply local air velocity from 0.5 to 2 m/s according to individual preference. This would reduce the electricity consumption of the air conditioning unit. According to the proposed method, this can save energy for office buildings in the commercial sector as high as 1959.51 GWh/year

Study of the Nafion quantity effect in membrane and electrodes assemblies (MEAs) of 50 cm{sup 2} used in type proton exchange membrane (PEM) fuel cell operating with H{sub 2}/Air; Estudo do efeito da quantidade de Nafion em MEAs de 50 cm{sup 2} utilizadas em celula a combustivel tipo PEM operando com H{sub 2}/ar

Energy Technology Data Exchange (ETDEWEB)

Profeti, Demetrius; Colmati, Flavio; Carlindo, Adao A.J.; Paganin, Valdecir A.; Gonzalez, Ernesto R.; Ticianelli, Edson A. [Universidade de Sao Paulo (USP), Sao Carlos, SP (Brazil). Inst. de Quimica]. E-mail: dprofeti@iqsc.usp.br

2008-07-01

The performance of a proton exchange membrane fuel cell (PEMFC) was investigated with the aim at characterizing the effects of the Nafion. content on the scale-up of the electrodes from 5 to 50 cm{sup 2}. It is observed that a diminution of the single cell performance occurred when the electrode area is increased from 5 to 50 cm{sup 2}. The tests carried out with different Nafion. contents, and fuel cell and humidifiers at the same temperature (T{sub cell}=T{sub H2}=T{sub air}=70 deg C) showed a slightly decrease of the fuel cell performance compared to the tests performed at different temperatures (T{sub cell}=70 deg C, T{sub H2}=85 deg C, T{sub air}=75 deg C). In the study of the variation on the Nafion. contents, the higher performance up to a current density of 0.8 A cm-2 is obtained with the 35.5 wt.% Nafion.. On the other hand, at higher current densities values, the performance of the fuel cells is very similar for the 31.0, 35.5 and 39.4 wt.% Nafion contents. (author)

Estimation of radioactive contaminants in Cm242 and Cm244 isotopic fuels

International Nuclear Information System (INIS)

Terent'ev, V.P.; Makarenko, A.I.

1972-01-01

The radiation properties of Cm 242 and Cm 244 preparations and the effect on them of possible contaminants are considered. One of the most important requirements for K alpha active fuels for radioisotope thermoelectric batteries is ensuring a low ionizing radiation background. In determining the effect of impurities on the radiation properties of a preparation, quantitative evaluation of certain factors is sufficient. In a Cm 242 preparation it is possible to show that Am 241 and Cm 243 are undesirable impurities. The presence of Am 241 increases the soft gamma output by 20%. The presence of Cm 243 may double the dose rate from an unshielded preparation and increase the hard gamma output 10-fold. The properties of Cm 242 preparations deteriorate when Am 243 and Cm 243 are present

Attached cavitation at a small diameter ultrasonic horn tip

Science.gov (United States)

Žnidarčič, Anton; Mettin, Robert; Cairós, Carlos; Dular, Matevž

2014-02-01

Ultrasonic horn transducers are frequently used in applications of acoustic cavitation in liquids, for instance, for cell disruption or sonochemical reactions. They are operated typically in the frequency range up to about 50 kHz and have tip diameters from some mm to several cm. It has been observed that if the horn tip is sufficiently small and driven at high amplitude, cavitation is very strong, and the tip can be covered entirely by the gas/vapor phase for longer time intervals. A peculiar dynamics of the attached cavity can emerge with expansion and collapse at a self-generated frequency in the subharmonic range, i.e., below the acoustic driving frequency. Here, we present a systematic study of the cavitation dynamics in water at a 20 kHz horn tip of 3 mm diameter. The system was investigated by high-speed imaging with simultaneous recording of the acoustic emissions. Measurements were performed under variation of acoustic power, air saturation, viscosity, surface tension, and temperature of the liquid. Our findings show that the liquid properties play no significant role in the dynamics of the attached cavitation at the small ultrasonic horn. Also the variation of the experimental geometry, within a certain range, did not change the dynamics. We believe that the main two reasons for the peculiar dynamics of cavitation on a small ultrasonic horn are the higher energy density on a small tip and the inability of the big tip to "wash" away the gaseous bubbles. Calculation of the somewhat adapted Strouhal number revealed that, similar to the hydrodynamic cavitation, values which are relatively low characterize slow cavitation structure dynamics. In cases where the cavitation follows the driving frequency this value lies much higher - probably at Str > 20. In the spirit to distinguish the observed phenomenon with other cavitation dynamics at ultrasonic transducer surfaces, we suggest to term the observed phenomenon of attached cavities partly covering the full horn

Intra-observer and inter-observer agreements for the measurement of dual-input whole tumor computed tomography perfusion in patients with lung cancer: Influences of the size and inner-air density of tumors.

Science.gov (United States)

Wang, Qingle; Zhang, Zhiyong; Shan, Fei; Shi, Yuxin; Xing, Wei; Shi, Liangrong; Zhang, Xingwei

2017-09-01

This study was conducted to assess intra-observer and inter-observer agreements for the measurement of dual-input whole tumor computed tomography perfusion (DCTP) in patients with lung cancer. A total of 88 patients who had undergone DCTP, which had proved a diagnosis of primary lung cancer, were divided into two groups: (i) nodules (diameter ≤3 cm) and masses (diameter >3 cm) by size, and (ii) tumors with and without air density. Pulmonary flow, bronchial flow, and pulmonary index were measured in each group. Intra-observer and inter-observer agreements for measurement were assessed using intraclass correlation coefficient, within-subject coefficient of variation, and Bland-Altman analysis. In all lung cancers, the reproducibility coefficient for intra-observer agreement (range 26.1-38.3%) was superior to inter-observer agreement (range 38.1-81.2%). Further analysis revealed lower agreements for nodules compared to masses. Additionally, inner-air density reduced both agreements for lung cancer. The intra-observer agreement for measuring lung cancer DCTP was satisfied, while the inter-observer agreement was limited. The effects of tumoral size and inner-air density to agreements, especially between two observers, should be emphasized. In future, an automatic computer-aided segment of perfusion value of the tumor should be developed. © 2017 The Authors. Thoracic Cancer published by China Lung Oncology Group and John Wiley & Sons Australia, Ltd.

Oxygen and air nanobubble water solution promote the growth of plants, fishes, and mice.

Directory of Open Access Journals (Sweden)

Kosuke Ebina

Full Text Available Nanobubbles (<200 nm in diameter have several unique properties such as long lifetime in liquid owing to its negatively charged surface, and its high gas solubility into the liquid owing to its high internal pressure. They are used in variety of fields including diagnostic aids and drug delivery, while there are no reports assessing their effects on the growth of lives. Nanobubbles of air or oxygen gas were generated using a nanobubble aerator (BUVITAS; Ligaric Company Limited, Osaka, Japan. Brassica campestris were cultured hydroponically for 4 weeks within air-nanobubble water or within normal water. Sweetfish (for 3 weeks and rainbow trout (for 6 weeks were kept either within air-nanobubble water or within normal water. Finally, 5 week-old male DBA1/J mice were bred with normal free-chaw and free-drinking either of oxygen-nanobubble water or of normal water for 12 weeks. Oxygen-nanobubble significantly increased the dissolved oxygen concentration of water as well as concentration/size of nanobubbles which were relatively stable for 70 days. Air-nanobubble water significantly promoted the height (19.1 vs. 16.7 cm; P<0.05, length of leaves (24.4 vs. 22.4 cm; P<0.01, and aerial fresh weight (27.3 vs. 20.3 g; P<0.01 of Brassica campestris compared to normal water. Total weight of sweetfish increased from 3.0 to 6.4 kg in normal water, whereas it increased from 3.0 to 10.2 kg in air-nanobubble water. In addition, total weight of rainbow trout increased from 50.0 to 129.5 kg in normal water, whereas it increased from 50.0 to 148.0 kg in air-nanobubble water. Free oral intake of oxygen-nanobubble water significantly promoted the weight (23.5 vs. 21.8 g; P<0.01 and the length (17.0 vs. 16.1 cm; P<0.001 of mice compared to that of normal water. We have demonstrated for the first time that oxygen and air-nanobubble water may be potentially effective tools for the growth of lives.

Development of Interfacial Structure in a Confined Air-Water Cap-Turbulent and Churn-Turbulent Flow

International Nuclear Information System (INIS)

Sun, X.; Kim, S.; Cheng, L.; Ishii, M.; Beus, S.G.

2001-01-01

The objective of the present work is to study and model the interfacial structure development of air-water two-phase flow in a confined test section. Experiments of a total of 9 flow conditions in a cap-turbulent and churn-turbulent flow regimes are carried out in a vertical air-water upward two-phase flow experimental loop with a test section of 20-cm in width and 1-cm in gap. The miniaturized four-sensor conductivity probes are used to measure local two-phase parameters at three different elevations for each flow condition. The bubbles captured by the probes are categorized into two groups in view of the two-group interfacial area transport equation, i.e., spherical/distorted bubbles as Group 1 and cap/churn-turbulent bubbles as Group 2. The acquired parameters are time-averaged local void fraction, interfacial velocity, bubble number frequency, interfacial area concentration, and bubble Sauter mean diameter for both groups of bubbles. Also, the line-averaged and area-averaged data are presented and discussed. The comparisons of these parameters at different elevations demonstrate the development of interfacial structure along the flow direction due to bubble interactions

Estimating air drying times of small-diameter ponderosa pine and Douglas-fir logs.

Science.gov (United States)

William T. Simpson; Xiping. Wang

2003-01-01

Because dense stands of softwood trees are causing forest health problems in the western United States, new ways to use this material need to be found. One option is to use this material as logs rather than sawing it into lumber. For many applications, logs require some degree of drying. Even though these logs may be considered small diameter, they are large compared...

Instability of Reference Diameter in the Evaluation of Stenosis After Coronary Angioplasty: Percent Diameter Stenosis Overestimates Dilative Effects Due to Reference Diameter Reduction

International Nuclear Information System (INIS)

Hirami, Ryouichi; Iwasaki, Kohichiro; Kusachi, Shozo; Murakami, Takashi; Hina, Kazuyoshi; Matano, Shigeru; Murakami, Masaaki; Kita, Toshimasa; Sakakibara, Noburu; Tsuji, Takao

2000-01-01

Purpose: To examine changes in the reference segment luminal diameter after coronary angioplasty.Methods: Sixty-one patients with stable angina pectoris or old myocardial infarction were examined. Coronary angiograms were recorded before coronary angioplasty (pre-angioplasty) and immediately after (post-angioplasty), as well as 3 months after. Artery diameters were measured on cine-film using quantitative coronary angiographic analysis.Results: The diameters of the proximal segment not involved in the balloon inflation and segments in the other artery did not change significantly after angioplasty, but the reference segment diameter significantly decreased (4.7%). More than 10% luminal reduction was observed in seven patients (11%) and more than 5% reduction was observed in 25 patients (41%). More than 5% underestimation of the stenosis was observed in 22 patients (36%) when the post-angioplasty reference diameter was used as the reference diameter, compared with when the pre-angioplasty measurement was used and more than 10% underestimation was observed in five patients (8%).Conclusion: This study indicated that evaluation by percent diameter stenosis, with the reference diameter from immediately after angioplasty, overestimates the dilative effects of coronary angioplasty, and that it is thus better to evaluate the efficacy of angioplasty using the absolute diameter in addition to percent luminal stenosis

Previsões climáticas sazonais sobre o Brasil: avaliação do RegCM3 aninhado no modelo global CPTEC/COLA Seasonal climatic forecast over Brazil: evaluation of the RegCM3 model nested to the CPTEC/COLA global model

Directory of Open Access Journals (Sweden)

Rubinei Dorneles Machado

2011-03-01

Full Text Available Este trabalho avalia o desempenho de previsões sazonais do modelo climático regional RegCM3, aninhado ao modelo global CPTEC/COLA. As previsões com o RegCM3 utilizaram 60 km de resolução horizontal num domínio que inclui grande parte da América do Sul. As previsões do RegCM3 e CPTEC/COLA foram avaliadas utilizando as análises de chuva e temperatura do ar do Climate Prediction Center (CPC e National Centers for Enviromental Prediction (NCEP, respectivamente. Entre maio de 2005 e julho de 2007, 27 previsões sazonais de chuva e temperatura do ar (exceto a temperatura do CPTEC/COLA, que possui 26 previsões foram avaliadas em três regiões do Brasil: Nordeste (NDE, Sudeste (SDE e Sul (SUL. As previsões do RegCM3 também foram comparadas com as climatologias das análises. De acordo com os índices estatísticos (bias, coeficiente de correlação, raiz quadrada do erro médio quadrático e coeficiente de eficiência, nas três regiões (NDE, SDE e SUL a chuva sazonal prevista pelo RegCM3 é mais próxima da observada do que a prevista pelo CPTEC/COLA. Além disto, o RegCM3 também é melhor previsor da chuva sazonal do que da média das observações nas três regiões. Para temperatura, as previsões do RegCM3 são superiores às do CPTEC/COLA nas áreas NDE e SUL, enquanto o CPTEC/COLA é superior no SDE. Finalmente, as previsões de chuva e temperatura do RegCM3 são mais próximas das observações do que a climatologia observada. Estes resultados indicam o potencial de utilização do RegCM3 para previsão sazonal, que futuramente deverá ser explorado através de previsão por conjunto.This study presents an assessment of seasonal forecasts from the regional climate model RegCM3 nested to the CPTEC/COLA global model. The used RegCM3 version is 60 km horizontal resolution over an area that includes large part of South America. RegCM3 and CPTEC/COLA forecasts were evaluated using the rainfall and air temperature analyses from Climate

Methane flux across the air-water interface - Air velocity effects

Science.gov (United States)

Sebacher, D. I.; Harriss, R. C.; Bartlett, K. B.

1983-01-01

Methane loss to the atmosphere from flooded wetlands is influenced by the degree of supersaturation and wind stress at the water surface. Measurements in freshwater ponds in the St. Marks Wildlife Refuge, Florida, demonstrated that for the combined variability of CH4 concentrations in surface water and air velocity over the water surface, CH4 flux varied from 0.01 to 1.22 g/sq m/day. The liquid exchange coefficient for a two-layer model of the gas-liquid interface was calculated as 1.7 cm/h for CH4 at air velocity of zero and as 1.1 + 1.2 v to the 1.96th power cm/h for air velocities from 1.4 to 3.5 m/s and water temperatures of 20 C.

SU-E-T-134: Assessing the Capabilities of An MU Model for Fields as Small as 2cm in a Passively Scattered Proton Beam

International Nuclear Information System (INIS)

Simpson, R; Ghebremedhin, A; Gordon, I; Patyal, B

2015-01-01

Purpose: To assess and expand the capabilities of the current MU model for a passively scattered proton beam. The expanded MU model can potentially be used to predict the dose/MU for fields smaller than 2cm in diameter and reduce time needed for physical calibrations. Methods: The current MU model accurately predicted the dose/MU for more than 800 fields when compared to physical patient calibrations. Three different ion chambers were used in a Plastic Water phantom for physical measurements: T1, PIN, and A-16. The original MU model predicted output for fields that were affected by the bolus gap factor (BGF) and nozzle extension factor (NEF). As the system was tested for smaller treatment fields, the mod wheel dependent field size factor (MWDFSF) had to be included to describe the changes observed in treatment fields smaller than 3cm. The expanded model used Clarkson integration to determine the appropriate value for each factor (field size factor (FSF), BGF, NEF, and MWDFSF), to accurately predict the dose/MU for fields smaller than 2.5cm in effective diameter. Results: The expanded MU model demonstrated agreement better than 2% for more than 800 physical calibrations that were tested. The minimum tested fields were 1.7cm effective diameter for 149MeV and 2.4cm effective diameter for 186MeV. The inclusion of Clarkson integration into the MU model enabled accurate prediction of the dose/MU for very small and irregularly shaped treatment fields. Conclusion: The MU model accurately predicted the dose/MU for a wide range of treatment fields used in the clinic. The original MU model has been refined using factors that were problematic to accurately predict the dose/MU: the BGF, NEF, and MWDFSF. The MU model has minimized the time for determining dose/MU and reduced the time needed for physical calibrations, improving the efficiency of the patient treatment process

Slug flooding in air-water countercurrent vertical flow

International Nuclear Information System (INIS)

Lee, Jae Young; Raman, Roger; Chang, Jen-Shih

2000-01-01

This paper is to study slug flooding in the vertical air-water countercurrent flow loop with a porous liquid injector in the upper plenum. More water penetration into the bottom plenum in slug flooding is observed than the annular flooding because the flow regime changes from the slug flow regime or periodic slug/annular flow regime to annular flow regime due to the hysteresis between the onset of flooding and the bridging film. Experiments were made tubes of 0.995 cm, 2.07 cm, and 5.08 cm in diameter. A mechanistic model for the slug flooding with the solitary wave whose height is four time of the mean film thickness is developed to produce relations of the critical liquid flow rate and the mean film thickness. After fitting the critical liquid flow rate with the experimental data as a function of the Bond number, the gas flow rate for the slug flooding is obtained by substituting the critical liquid flow rate to the annular flooding criteria. The present experimental data evaluate the slug flooding condition developed here by substituting the correlations for mean film thickness models in the literature. The best prediction was made by the correlation for the mean film thickness of the present study which is same as Feind's correlation multiplied by 1.35. (author)

[Assessment of the air quality improment of cleaning and disinfection on central air-conditioning ventilation system].

Science.gov (United States)

Liu, Hongliang; Zhang, Lei; Feng, Lihong; Wang, Fei; Xue, Zhiming

2009-09-01

To assess the effect of air quality of cleaning and disinfection on central air-conditioning ventilation systems. 102 air-conditioning ventilation systems in 46 public facilities were sampled and investigated based on Hygienic assessment criterion of cleaning and disinfection of public central air-conditioning systems. Median dust volume decreased from 41.8 g/m2 to 0.4 g/m2, and the percentage of pipes meeting the national standard for dust decreased from 17.3% (13/60) to 100% (62/62). In the dust, median aerobic bacterial count decreased from 14 cfu/cm2 to 1 cfu/cm2. Median aerobic fungus count decreased from 10 cfu/cm2 to 0 cfu/cm2. The percentage of pipes with bacterial and fungus counts meeting the national standard increased from 92.4% (171/185) and 82.2% (152/185) to 99.4% (165/166) and 100% (166/166), respectively. In the ventilation air, median aerobic bacterial count decreased from 756 cfu/m3 to 229 cfu/m3. Median aerobic fungus count decreased from 382 cfu/m3 to 120 cfu/m3. The percentage of pipes meeting the national standard for ventilation air increased from 33.3% (81/243) and 62.1% (151/243) to 79.8% (292/366) and 87.7% (242/276), respectively. But PM10 rose from 0.060 mg/m3 to 0.068 mg/m3, and the percentage of pipes meeting the national standard for PM10 increased from 74.2% (13/60) to 90.2% (46/51). The cleaning and disinfection of central air-conditioning ventilation systems could have a beneficial effect of air quality.

One-pot synthesis of La0.7Sr0.3MnO3 supported on flower-like CeO2 as electrocatalyst for oxygen reduction reaction in aluminum-air batteries

Science.gov (United States)

Xue, Yejian; Huang, Heran; Miao, He; Sun, Shanshan; Wang, Qin; Li, Shihua; Liu, Zhaoping

2017-08-01

A novel La0.7Sr0.3MnO3-CeO2 (LSM-CeO2) hybrid catalyst for oxygen reduction reaction (ORR) has been synthesized by a facile one-pot method. The flower-like CeO2 with the diameter of about 3 μm is formed by the agglomeration of nanosheets with the thickness of about 40 nm. The LSM particles with the diameter of about 150 nm are well distributed on the flower-like CeO2, thus the interaction between LSM and CeO2 is built. Therefore, the LSM-CeO2 composite catalyst exhibits the much higher catalytic activity toward ORR with the direct four-electron transfer mechanism in alkaline solution than LSM or CeO2. Furthermore, the stability of LSM-CeO2 is superior to that of Pt/C, and the current retention is 93% after 100000 s. The maximum power density of the aluminum-air battery using LSM-CeO2 as the ORRC can reach 238 mW cm-2, which is about 29% higher than that with LSM (184 mW cm-2). It indicates that LSM-CeO2 composite material is a promising cathodic electrocatalyst for metal-air batteries.

Development of a Modelling to Correlate Site and Diameter of Brain Metastases with Hippocampal Sparing Using Volumetric Modulated Arc Therapy

Directory of Open Access Journals (Sweden)

Silvia Chiesa

2013-01-01

Full Text Available Purpose. To correlate site and diameter of brain metastases with hippocampal sparing in patients treated by RapidArc (RA technique on whole brain with simultaneously integrated boost (SIB. Methods and Materials. An RA plan was calculated for brain metastases of 1-2-3 cm of diameter. The whole brain dose was 32.25 Gy (15 fractions, and SIB doses to brain metastases were 63 Gy (2 and 3 cm or 70.8 Gy (1 cm. Plans were optimized and evaluated for conformity, target coverage, prescription isodose to target volume, homogeneity index, and hippocampal sparing. Results. Fifteen brain lesions and RA plan were generated. Hippocampal volume was 4.09 cm3, and hippocampal avoidance volume was 17.50 cm3. Related to site of metastases, the mean hippocampal dose was 9.68 Gy2 for occipital lobe, 10.56 Gy2 for frontal lobe, 10.56 Gy2 for parietal lobe, 10.94 Gy2 for deep brain structures, and 40.44 Gy2 for temporal lobe. The mean hippocampal dose was 9.45 Gy2, 10.15 Gy2, and 11.70 Gy2 for diameter’s metastases of 1.2 and 3 cm, respectively, excluding results relative to temporal brain lesions. Conclusions. Location more than size of metastases can adversely influence the hippocampus sparing. Further investigation is necessary to meet definitive considerations.

Sugar maple height-diameter and age-diameter relationships in an uneven-aged northern hardwood stand

Science.gov (United States)

Laura S. Kenefic; R.D. Nyland

1999-01-01

Sugar maple (Acer saccharum Marsh.) height-diameter and age-diameter relationships are explored in a balanced uneven-aged northern hardwood stand in central New York. Results show that although both height and age vary considerably with diameter, these relationships can be described by statistically valid equations. The age-diameter relationship...

Investigation of column flotation process on sulphide ore using 2-electrode capacitance sensor: The effect of air flow rate and solid percentage

Science.gov (United States)

Haryono, Didied; Harjanto, Sri; Wijaya, Rifky; Oediyani, Soesaptri; Nugraha, Harisma; Huda, Mahfudz Al; Taruno, Warsito Purwo

2018-04-01

Investigation of column flotation process on sulphide ore using 2-electrode capacitance sensor is presented in this paper. The effect of air flow rate and solid percentage on column flotation process has been experimentally investigated. The purpose of this paper is to understand the capacitance signal characteristic affected by the air flow rate and the solid percentage which can be used to determine the metallurgical performance. Experiments were performed using a laboratory column flotation cell which has a diameter of 5 cm and the total height of 140 cm. The sintered ceramic sparger and wash water were installed at the bottom and above of the column. Two-electrode concave type capacitance sensor was also installed at a distance of 50 cm from the sparger. The sensor was attached to the outer wall of the column, connected to data acquisition system, manufactured by CTECH Labs Edwar Technology and personal computer for further data processing. Feed consisting ZnS and SiO2 with the ratio of 3:2 was mixed with some reagents to make 1 litre of slurry. The slurry was fed into the aerated column at 100 cm above the sparger with a constant rate and the capacitance signals were captured during the process. In this paper, 7.5 and 10% of solid and 2-4 L/min of air flow rate with 0.5 L/min intervals were used as independent variables. The results show that the capacitance signal characteristics between the 7.5 and 10% of solid are different at any given air flow rate in which the 10% solid produced signals higher than those of 7.5%. Metallurgical performance and capacitance signal exhibit a good correlation.

Fourier transform measurements of water vapor line parameters in the 4200-6600 cm{sup -1} region

Energy Technology Data Exchange (ETDEWEB)

Jenouvrier, Alain [Groupe de Spectrometrie Moleculaire et Atmospherique, UMR CNRS 6089, UFR Sciences, Moulin de la Housse, B.P. 1039, 51067 Reims Cedex 2 (France)]. E-mail: alain.jenouvrier@univ-reims.fr; Daumont, Ludovic [Groupe de Spectrometrie Moleculaire et Atmospherique, UMR CNRS 6089, UFR Sciences, Moulin de la Housse, B.P. 1039, 51067 Reims Cedex 2 (France); Regalia-Jarlot, Laurence [Groupe de Spectrometrie Moleculaire et Atmospherique, UMR CNRS 6089, UFR Sciences, Moulin de la Housse, B.P. 1039, 51067 Reims Cedex 2 (France); Tyuterev, Vladimir G. [Groupe de Spectrometrie Moleculaire et Atmospherique, UMR CNRS 6089, UFR Sciences, Moulin de la Housse, B.P. 1039, 51067 Reims Cedex 2 (France); Carleer, Michel [Service de Chimie Quantique et de Photophysique, CP 160/09, Universite Libre de Bruxelles, 50 Av. F.D. Roosevelt, B-1050 Brussels (Belgium); Vandaele, Ann Carine [Institut d' Aeronomie Spatiale de Belgique, Av. Circulaire 3, B-1180 Brussels (Belgium); Mikhailenko, Semen [Laboratory of Theoretical Spectroscopy, Institute of Atmospheric Optics, Russian Academy of Sciences, 1, Av. Akademichesskii, 634055 Tomsk (Russian Federation); Fally, Sophie [Service de Chimie Quantique et de Photophysique, CP 160/09, Universite Libre de Bruxelles, 50 Av. F.D. Roosevelt, B-1050 Brussels (Belgium)

2007-06-15

New high-resolution water vapor absorption spectra were obtained at room temperature in the 4200-6600 cm{sup -1} spectral region by combining Fourier transform spectrometers (FTS) with single and multiple reflection cells. With absorption paths from 0.3 to 1800 m in pure and air diluted water vapor, accurate measurements of about 10400 lines in an intensity range from 10{sup -29} to 10{sup -19} cm/molecule have been performed. Positions, intensities, self- and air-broadening coefficients and air-induced shifts were determined for the H{sub 2} {sup 16}O, H{sub 2} {sup 17}O, H{sub 2} {sup 18}O and HDO isotopologues. The rovibrational assignment of the observed lines was performed with the use of global variational predictions and allowed the identification of several new energy levels. One major contribution of this work consists of the identification of 3280 new weak lines. A very close agreement between the new measured parameters and those listed in the database is reported as well as between the observations and the most recent variational calculations for the positions and the intensities. The present parameters provide an extended and homogeneous data set for water vapor, which is shown to significantly improve the databases for atmospheric applications, especially in the transmission windows on both sides of the band centered at 5400 cm{sup -1}.

Intercontinental Transport of Aerosols: Implication for Regional Air Quality

Science.gov (United States)

Chin, Mian; Diehl, Thomas; Ginoux, Paul

2006-01-01

Aerosol particles, also known as PM2.5 (particle diameter less than 2.5 microns) and PM10 (particle diameter less than 10 microns), is one of the key atmospheric components that determine ambient air quality. Current US air quality standards for PM10 (particles with diameter air pollution problems, aerosols can be transported on a hemispheric or global scale. In this study, we use the Goddard Chemistry Aerosol Radiation and Transport (GOCART) model to quantify contributions of long-range transport vs. local/regional pollution sources and from natural vs. anthropogenic sources to PM concentrations different regions. In particular, we estimate the hemispheric impact of anthropogenic sulfate aerosols and dust from major source areas on other regions in the world. The GOCART model results are compared with satellite remote sensing and ground-based network measurements of aerosol optical depth and concentrations.

Evaluation of neutron cross sections for 244Cm, 246Cm, and 248Cm

International Nuclear Information System (INIS)

Benjamin, R.W.; McCrosson, F.J.; Gettys, W.E.

1977-01-01

An evaluation of neutron cross sections for 244 246 248 Cm using the ENDF/B format is presented. Primary data input included differential measurements, integral measurements, nuclear model calculations, and reactor production experience

243Cm half-life determinaton

International Nuclear Information System (INIS)

Timofeev, G.A.; Kalygin, V.V.; Privalova, P.A.

1986-01-01

By molar ratios of 243 Cm mixture with 244 Cm and Pu nuclides formed as a result of Cm nuclides α-decay the 243 Cm half-life T α243 is determined. The 244 Cm half-life is measured earlier with high accuracy. The 243 Cm/ 244 Cm ratio measured by means of a mass spectrometer equals 0.989+-0.004. The obtained value T α243 =29.20+-0.14 years

The effect of nozzle diameter, injection pressure and ambient temperature on spray characteristics in diesel engine

Science.gov (United States)

Rhaodah Andsaler, Adiba; Khalid, Amir; Sharifhatul Adila Abdullah, Nor; Sapit, Azwan; Jaat, Norrizam

2017-04-01

Mixture formation of the ignition process is a key element in the diesel combustion as it influences the combustion process and exhaust emission. Aim of this study is to elucidate the effects of nozzle diameter, injection pressure and ambient temperature to the formation of spray. This study investigated diesel formation spray using Computational Fluid Dynamics. Multiphase volume of fluid (VOF) behaviour in the chamber are determined by means of transient simulation, Eulerian of two phases is used for implementation of mixing fuel and air. The detail behaviour of spray droplet diameter, spray penetration and spray breakup length was visualised using the ANSYS 16.1. This simulation was done in different nozzle diameter 0.12 mm and 0.2 mm performed at the ambient temperature 500 K and 700 K with different injection pressure 40 MPa, 70 MPa and 140 MPa. Results show that high pressure influence droplet diameter become smaller and the penetration length longer with the high injection pressure apply. Smaller nozzle diameter gives a shorter length of the breakup. It is necessary for nozzle diameter and ambient temperature condition to improve the formation of spray. High injection pressure is most effective in improvement of formation spray under higher ambient temperature and smaller nozzle diameter.

Experimental analysis of heat transfer between a heated wire and a rarefied gas in an annular gap with high diameter ratio

International Nuclear Information System (INIS)

Chalabi, H; Lorenzini, M; Morini, G L; Buchina, O; Valougeorgis, D; Saraceno, L

2012-01-01

In this paper a first experimental attempt is performed to measure heat conduction through rarefied air at rest contained between two concentric cylinders. The heat transfer between a heated platinum wire having a diameter (d) of 0.15 mm, disposed along the axis of a cylindrical shell in stainless steel having an inner diameter (D) of 100 mm, and a surrounded rarefied gas has been studied experimentally and numerically. The ratio between the outer and inner diameter of the annular region filled by the gas is large (D/d=667). In the annular region filled with air the pressure was varied by using a vacuum pump from atmospheric value down to 10 −3 mbar. Temperature differences between the wire and the external stainless steel wall in the range 50-125 K were imposed and the heat power transferred from the wire to the surround was measured as a function of the gas pressure starting from air at atmospheric conditions down to 10 −3 mbar. The experimental results obtained in these tests were compared with the numerical results obtained by using the linear and nonlinear Shakhov kinetic models.

Inlet Diameter and Flow Volume Effects on Separation and Energy Efficiency of Hydrocyclones

Science.gov (United States)

Erikli, Ş.; Olcay, A. B.

2015-08-01

This study investigates hydrocyclone performance of an oil injected screw compressor. Especially, the oil separation efficiency of a screw compressor plays a significant role for air quality and non-stop working hour of compressors has become an important issue when the efficiency in energy is considered. In this study, two separation efficiency parameters were selected to be hydrocyclone inlet diameter and flow volume height between oil reservoir surface and top of the hydrocyclone. Nine different cases were studied in which cyclone inlet diameter and flow volume height between oil reservoir surface and top were investigated in regards to separation and energy performance aspects and the effect of the parameters on the general performance appears to be causing powerful influence. Flow inside the hydrocyclone geometry was modelled by Reynolds Stress Model (RSM) and hydro particles were tracked by Discrete Phase Model (DPM). Besides, particle break up was modelled by the Taylor Analogy Breakup (TAB) model. The reversed vortex generation was observed at different planes. The upper limit of the inlet diameter of the cyclone yields the centrifugal force on particles to decrease while the flow becomes slower; and the larger diameter implies slower flow. On the contrary, the lower limit is increment in speed causes breakup problems that the particle diameters become smaller; consequently, it is harder to separate them from gas.

Uptake and distribution of Pu, Am, Cm and Np in four plant species

Energy Technology Data Exchange (ETDEWEB)

Schreckhise, R G; Cline, J F [Battelle, Pacific Northwest Laboratories, Richland, WA (United States)

1978-12-01

The relative uptake of the nitrate forms of {sup 238}Pu, {sup 239}Pu, {sup 241}Sm, {sup 244}Cm and {sup 237}Np from soil into selectee parts of four different plant species grown under field conditions were observed. Cheatgrass (Bromus tectorum L.), peas (Pisum sativum, var. Blue Bonnet), barley (Hordeum vulgare, var. U. Cal. Briggs), and alfalfa (Medicago sativa, var. Ranger) were grown outdoors in contaminated soil contained in small weighing lysimeters constructed from 13.2 cm diameter by 1-meter-long polyvinyl chloride pipe. The amended soil, containing 0.1 to 1.0 mCi of each isotope individually per 3.4 kg soil, was situated in a 20 cm band and covered by 10 cm of uncontaminated soil to eliminate chances of windblown contamination to the surrounding environs. The plants were harvested at maturity, divided into selected components and radiochemically analyzed by alpha-energy analysis. There did not appear to be any effect of soil concentration on the plant uptake of {sup 238}Pu, {sup 239}Pu, {sup 241}Am or {sup 244}Cm for the two levels utilized (approximately 0.03 and 0.3 {mu}Ci/g soil). The relative uptake of {sup 238}Pu and {sup 239}Pu were not significantly different. Likewise, {sup 241} Am uptake values were not significantly different from the {sup 244}Cm values. The relative plant uptake of the four different transuranium element was: Np > Cm {approx} Am > Pu. The relative uptake values of Np were 2,200 to 45,000 times greater than for Pu, while Am and Cm values were 10 to 20 times greater. The seeds were significantly lower than the rest of the above ground plant parts for all four transuranics. The legumes accumulated approximately ten times more than the grasses. A hypothetical comparison of the radionuclide content of plants grown in soil contaminated with LMFBR fuels indicate that Am, Cm and Np concentrations would exceed Pu values. (author)

When the diameter of the abdominal aorta should be considered as abnormal? A new ultrasonographic index using the wrist circumference as a body build reference

International Nuclear Information System (INIS)

Sconfienza, Luca Maria; Santagostino, Ilaria; Di Leo, Giovanni; Piazza, Raffaella; Gozzi, Gino; Trimarchi, Santi; Sardanelli, Francesco

2013-01-01

Purpose: To use US to evaluate the normal values of aortic diameter (AD), stratifying the population by age, gender and body build, as measured using wrist circumference (WC). Materials and methods: Between April 2010 and February 2012, consecutive patients ≥ 30 years of age, without history of abdominal aortic aneurysm (AAA) were prospectively enrolled. They underwent an abdominal ultrasonography for reasons other than aorta evaluation. AD was measured at the infrarenal (AD 1 ), intermediate (AD 2 ), and iliac bifurcation (AD 3 ) levels: a diameter ≥ 3 cm was considered as an aneurysm. The maximal aortic diameter (AD max ) was measured for AAA patients. WC was measured; AD/WC ratio was calculated and presented in percentage: the range of normal values was obtained excluding AAA cases and calculated as mean ± 1.96 × standard deviation. Pearson correlation coefficient was used. Results: We recruited 1200 patients, 15 (1.25%; age range = 64–86 years) had AAA. AD ranges of the other patients were: AD 1 = 0.74–1.84 cm, AD 2 = 0.78–1.85 cm, and AD 3 = 0.68–1.76 cm for females; AD 1 = 0.86–2.02 cm, AD 2 = 0.91–2.08 cm, and AD 3 = 0.84–1.95 cm for males. AD 2 /WC ratio of non-AAA patients range was 4–15%, with only one outlier at 18%, while AD max /WC ratio of AAA patients range was 15–35% (p 1 , r = 0.318, p 2 and r = 0.280, p 3 ). Conclusion: The definition of normal AD should consider body build. An AD 2 /WC ratio of 15% may be regarded as a threshold to differentiate AAA- from non-AAA patients. Patients with AD 2 /WC values comprised between 12% and 15% may be at risk for AAA

KOMBINASI INJEKSI sGNRH-a + ad , PADA KETINGGIAN AIR YANG BERBEDA UNTUK PEMIJAHAN SNAKEHEAD , Channa Striata DI WADAH BUDIDAYA

Directory of Open Access Journals (Sweden)

Untung Bijaksana

2016-06-01

Full Text Available Penelitian ini bertujuan untuk melihat efektivitas sGnRH-a+ad dan ketinggian air yang berbeda pada pemijahan ikan snakehead, Channa striata dalam tangki concreat. Penelitian ini dilakukan di Laboratorium Basah Program Studi Budidaya Perairan Fakultas Perikanan Universitas Lambung Mangkurat . Ada dua faktor utama sebagai perlakuan yaitu: Faktor A = dosis sGnRH -a + ad dengan tiga tingkat ( A1 = 0,2 ml / kg , A2 = 0,4 ml / kg , A3 = 0,6 ml / kg dan faktor B = tinggi air dengan tiga tingkat ( B1 = 15 cm; B2 = 20 cm; B3 = 25 cm   diulang 4 kali untuk mendapatkan 36 unit percobaan. Pengamatan dilakukan pada parameter : berat badan, berat gonad, berat hati , estradiol - 17β , diameter telur, IGS, IHS, fekunditas, pemupukan dan derajat penetasan. Terdapat Hubungan yagn sangat erat atara parameter pengamatan IGS dan IHS.  Perlakuan yang diberikan waktu laten diperoleh kisaran  antara 12 jam sampai 25 jam, fekunditas antara 5047-5072 butir, derajat fertilisasi antara 60-60,3 persen dan 76,6 derajat fertilisasi antara 83,9 persen.  Perkembangan setelah menetas mencapai panjang tubuh 3,5 mm dan 45,5 mm pada hari 20 . This study aims to look at the effectiveness of injection of sGnRH-a + ad and height of water on fish spawning snakehead, Channa striata in the concreat tank. The research was conducted at the Wet Laboratory Aguaculture Departement Faculty of Fisheries University of Lambung Mangkurat. There are two main factors as treatment namely: Factor A = dose of sGnRH-a + ad with three levels (A1 = 0.2 ml / kg; A2 = 0.4 ml / kg; A3 = 0.6 ml / kg and factor B = height of water with three levels (B1 = 15 cm; B2 = 20 cm; B3 = 25 cm made repeated 4 times to obtain 36 units of the experiment. Observations made on the parameters: body weight, gonad weight, liver weight, estradiol-17β, egg diameter, IGS, IHS, fecundity, fertilization and hatching degrees. The strongest relationship obtained from the treatment of observational parameter is IGS and IHS. Of

Commuters’ Exposure to Particulate Matter Air Pollution Is Affected by Mode of Transport, Fuel Type, and Route

Science.gov (United States)

Zuurbier, Moniek; Hoek, Gerard; Oldenwening, Marieke; Lenters, Virissa; Meliefste, Kees; van den Hazel, Peter; Brunekreef, Bert

2010-01-01

Background Commuters are exposed to high concentrations of air pollutants, but little quantitative information is currently available on differences in exposure between different modes of transport, routes, and fuel types. Objectives The aim of our study was to assess differences in commuters’ exposure to traffic-related air pollution related to transport mode, route, and fuel type. Methods We measured particle number counts (PNCs) and concentrations of PM2.5 (particulate matter ≤ 2.5 μm in aerodynamic diameter), PM10, and soot between June 2007 and June 2008 on 47 weekdays, from 0800 to 1000 hours, in diesel and electric buses, gasoline- and diesel-fueled cars, and along two bicycle routes with different traffic intensities in Arnhem, the Netherlands. In addition, each-day measurements were taken at an urban background location. Results We found that median PNC exposures were highest in diesel buses (38,500 particles/cm3) and for cyclists along the high-traffic intensity route (46,600 particles/cm3) and lowest in electric buses (29,200 particles/cm3). Median PM10 exposure was highest from diesel buses (47 μg/m3) and lowest along the high- and low-traffic bicycle routes (39 and 37 μg/m3). The median soot exposure was highest in gasoline-fueled cars (9.0 × 10−5/m), diesel cars (7.9 × 10−5/m), and diesel buses (7.4 × 10−5/m) and lowest along the low-traffic bicycle route (4.9 × 10−5/m). Because the minute ventilation (volume of air per minute) of cyclists, which we estimated from measured heart rates, was twice the minute ventilation of car and bus passengers, we calculated that the inhaled air pollution doses were highest for cyclists. With the exception of PM10, we found that inhaled air pollution doses were lowest for electric bus passengers. Conclusions Commuters’ rush hour exposures were significantly influenced by mode of transport, route, and fuel type. PMID:20185385

Implantation technique of the 50-cm3 SynCardia Total Artificial Heart: does size make a difference?

Science.gov (United States)

Spiliopoulos, Sotirios; Guersoy, Dilek; Dimitriou, Alexandros Merkourios; Koerfer, Reiner; Tenderich, Gero

2015-01-01

Despite downsizing, implantation technique of the 50-cm(3) SynCardia Total Artificial Heart and settings of the Companion driver remain unchanged. Owing to the absence of de-airing nipples, de-airing procedure is even more crucial and has to be performed carefully. © The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.

Preparation of 2-in.-diameter (001) β-Ga2O3 homoepitaxial wafers by halide vapor phase epitaxy

Science.gov (United States)

Thieu, Quang Tu; Wakimoto, Daiki; Koishikawa, Yuki; Sasaki, Kohei; Goto, Ken; Konishi, Keita; Murakami, Hisashi; Kuramata, Akito; Kumagai, Yoshinao; Yamakoshi, Shigenobu

2017-11-01

The homoepitaxial growth of thick β-Ga2O3 layers on 2-in.-diameter (001) wafers was demonstrated by halide vapor phase epitaxy. Growth rates of 3 to 4 µm/h were confirmed for growing intentionally Si-doped n-type layers. A homoepitaxial layer with an average thickness and carrier concentration of 10.9 µm and 2.7 × 1016 cm-3 showed standard deviations of 1.8 µm (16.5%) and 0.5 × 1016 cm-3 (19.7%), respectively. Ni Schottky barrier diodes fabricated directly on a 5.3-µm-thick homoepitaxial layer with a carrier concentration of 3.4 × 1016 cm-3 showed reasonable reverse and forward characteristics, i.e., breakdown voltages above 200 V and on-resistances of 3.8-7.7 mΩ cm2 at room temperature.

Prospective comparison of air-contrast barium enema and colonoscopy in patients with fecal occult blood: a pilot study.

Science.gov (United States)

Rockey, Don C; Koch, Johannes; Yee, Judy; McQuaid, Kenneth R; Halvorsen, Robert A

2004-12-01

The utility of air-contrast barium enema and colonoscopy for evaluation of the colon has been debated. Air-contrast barium enema is less expensive and invasive than colonoscopy, but it also is less sensitive and specific. Further, although air-contrast barium enema may be less painful than colonoscopy, it often is poorly tolerated by patients. Thus, this study compared the sensitivity and the specificity of air-contrast barium enema and colonoscopy for detection of colonic lesions in patients with fecal occult blood. Over a 30-month period, patients with fecal occult blood were recruited. Patients underwent standard air-contrast barium enema, followed by colonoscopy 7 to 14 days later. Colonoscopists were blinded to the results of air-contrast barium enema until the colonoscopy was completed, after which the results were disclosed. If the findings were discrepant, colonoscopy was repeated. A total of 100 patients were evaluated. Nine air-contrast barium enemas were reported to be inadequate, and the cecum was not intubated at colonoscopy in two patients. In the remaining patients, 5 cancers were identified (1 each cecum, transverse colon, descending colon, sigmoid colon, and rectum) by both studies. Sixty-six polypoid lesions were identified in 30 patients. Diverticula were identified in 42 patients by air-contrast barium enema and in 18 patients by colonoscopy. Air-contrast barium enema detected 3 of 36 polypoid lesions 5 mm or less in diameter, 5 of 15 adenomas 6 to 9 mm in size, and 4 of 15 adenomas 10 mm or greater in diameter (sensitivity 8%, 33%, and 27%, respectively). After excluding patients with diverticula, air-contrast barium enema detected 3 of 7 adenomas 10 mm or greater in size. Overall, 12 polypoid lesions or filling defects were identified by air-contrast barium enema that could not be verified by colonoscopy. The specificity of air-contrast barium enema for lesions 1.0 cm or greater in size was 100%; for those 6 mm or greater, it was 97%. Air

Controlling the diameters and field emission properties of vertically aligned carbon nanotubes synthesized by thermal chemical vapor deposition

International Nuclear Information System (INIS)

Choi, Sung Yool; Kang, Young Il; Cho, Kyoung Ik; Choi, Kyu Seok; Kim, Do Jin

2001-01-01

We report here the synthesis of vertically well-aligned carbon nanotubes and the effect of catalytic metal layer on the diameter of grown carbon nanotubes and the field emission characteristics of them, The carbon nanotubes were grown by thermal chemical vapor deposition at temperatures below 900 .deg. C on Fe metal catalytic layer, deposited by sputtering process on a Si substrate and pretreated by heat and NH 3 gas. We found that the thickness of metal layers could be an important parameter in controlling the diameters of carbon nanotubes. With varying the thickness of the metal layers the grain sizes of them also vary so that the diameters of the nanotubes could be controlled. Field emission measurement has been made on the carbon nanotube field emitters at room temperature in a vacuum chamber below 10 -6 Torr. Our vertically aligned carbon nanotube field emitter of the smallest diameter emits a current density about 10 mA/cm 2 at 7.2 V/μm. The field emission property of the carbon nanotubes shows strong dependence on the nanotube diameters as expected

Neutron spectra of /sup 242/Cm-Be and /sup 244/Cm-Be neutron sources

Energy Technology Data Exchange (ETDEWEB)

Kumar, A; Nagarajan, P S [Bhabha Atomic Research Centre, Bombay (India). Div. of Radiation Protection

1977-02-15

Neutron spectra of /sup 242/Cm-Be(..cap alpha..,n) and /sup 244/Cm-Be(..cap alpha..,n) sources have been calculated including the spontaneous fission contribution which is negligible for /sup 242/Cm and amounts to about 4% for /sup 244/Cm. The agreement of the present work with experimental results is poor.

Piezo-Operated Shutter Mechanism Moves 1.5 cm

Science.gov (United States)

Glaser, Robert; Bamford, Robert

2005-01-01

The figure shows parts of a shutter mechanism designed to satisfy a number of requirements specific to its original intended application as a component of an atomic clock to be flown in outer space. The mechanism may also be suitable for use in laboratory and industrial vacuum systems on Earth for which there are similar requirements. The requirements include the following: a) To alternately close, then open, a 1.5-cm-diameter optical aperture twice per second, with a stroke time of no more than 15 ms, during a total operational lifetime of at least a year; b) To attenuate light by a factor of at least 1012 when in the closed position; c) To generate little or no magnetic field; d) To be capable of withstanding bakeout at a temperature of 200 C to minimize outgassing during subsequent operation in an ultrahigh vacuum; and e) To fit within a diameter of 12 in. (=305 mm) a size limit dictated by the size of an associated magnetic shield. The light-attenuation requirement is satisfied by use of overlapping shutter blades. The closure of the aperture involves, among other things, insertion of a single shutter blade between a pair of shutter blades. The requirement to minimize the magnetic field is satisfied by use of piezoelectric actuators. Because piezoelectric actuators cannot withstand bakeout, they must be mounted outside the vacuum chamber, and, hence, motion must be transmitted from the actuators to the shutter levers via a vacuum-chamber-wall diaphragm.

Accumulation of logging residue in first thinnings of Scots pine and Norway spruce. Impact of top bucking diameter of roundwood

Energy Technology Data Exchange (ETDEWEB)

Raeisaenen, T.; Nurmi, J. (Finnish Forest Research Inst., Kannus (Finland)), e-mail: tommi.raisanen@metla.fi

2010-07-01

The aim of this study was to examine the impacts of changes in the minimum top diameter of roundwood on the accumulation of logging residue. The aim was also to compare estimates of residue accumulation calculated by tree-specific biomass models with field measurements from thinnings. Felling experiments were performed in first thinnings of pine and spruce to evaluate the model calculations. In the felling, mean relative masses of the tree tops of spruce were nearly doubled with each increment of 2 cm in the top diameter. Respectively in pine, the mean relative tree top mass was increased by 50-60 % when the top diameter was increased by 2 cm. The mass of total residue (tree top and all delimbed branches) was similarly increased, but the differences were not as large. Compared to pine, a lesser variation in the crown mass of the spruce sample resulted in a more accurate model prediction of masses of tree tops and total residue. The results indicate that the residue accumulation from a small group of trees cannot be predicted very reliably, but when a larger tree population or area is considered, the model predictions are enhanced to a more practicable level. (orig.)

Turbulent water flow in a channel at Reτ = 400 laden with 0.25 mm diameter air-bubbles clustered near the wall

Science.gov (United States)

Lakehal, D.; Métrailler, D.; Reboux, S.

2017-06-01

This paper presents Direct Numerical Simulation (DNS) results of a turbulent water flow in a channel at Reτ = 400 laden with 0.25 mm diameter air bubbles clustered near the wall (maximum void fraction of α = 8% at y+ ˜ 20). The bubbles were fully resolved using the level set approach built within the CFD/CMFD code TransAT. The fluid properties (air and water) were kept real, including density, viscosity, and surface tension coefficient. The aim of this work is to understand the effects of the bubbles on near-wall turbulence, paving the way towards convective wall-boiling flow studies. The interactions between the gas bubbles and the water stream were studied through an in-depth analysis of the turbulence statistics. The near-wall flow is overall affected by the bubbles, which act like roughness elements during the early phase, prior to their departure from the wall. The average profiles are clearly altered by the bubbles dynamics near the wall, which somewhat contrasts with the findings from similar studies [J. Lu and G. Tryggvason, "Dynamics of nearly spherical bubbles in a turbulent channel upflow," J. Fluid Mech. 732, 166 (2013)], most probably because the bubbles were introduced uniformly in the flow and not concentrated at the wall. The shape of the bubbles measured as the apparent to initial diameter ratio is found to change by a factor of at least two, in particular at the later stages when the bubbles burst out from the boundary layer. The clustering of the bubbles seems to be primarily localized in the zone populated by high-speed streaks and independent of their size. More importantly, the bubbly flow seems to differ from the single-phase flow in terms of turbulent stress distribution and energy exchange, in which all the stress components seem to be increased in the region very close to the wall, by up to 40%. The decay in the energy spectra near the wall was found to be significantly slower for the bubbly flow than for a single-phase flow, which

Diameter-speed relation of sprite streamers

International Nuclear Information System (INIS)

Kanmae, T; Stenbaek-Nielsen, H C; McHarg, M G; Haaland, R K

2012-01-01

Propagation and splitting of sprite streamers has been observed at high temporal and spatial resolution using two intensified high-speed CMOS cameras recording at 10 000 and 16 000 frames per second. Concurrent video recordings from a remote site provided data for triangulation allowing us to determine accurate altitude scales for the sprites. Diameters and speeds of the sprite streamers were measured from the high-speed images, and the diameters were scaled to the reduced diameters based on the triangulated locations. The sprite streamers with larger reduced diameter move faster than those with smaller diameter; the relation between the reduced diameter and speed is roughly linear. The reduced diameters at ≈65-70 km altitude are larger than streamer diameters measured at ground pressure in laboratory discharges indicating a deviation from the similarity law possibly due to the effects of the photoionization and an expansion of the streamer head along its propagation over a long distance. The reduced diameter and speed of the sprite streamers agree well with the diameter-velocity relation proposed by Naidis (2009 Phys. Rev. E 79 057401), and the peak electric field of the sprite streamers is estimated to be approximately 3-5 times the breakdown threshold field. (paper)

Exposure to nanoscale and microscale particulate air pollution prior to mining development near a northern indigenous community in Québec, Canada.

Science.gov (United States)

Ghoshdastidar, Avik J; Hu, Zhenzhong; Nazarenko, Yevgen; Ariya, Parisa A

2018-03-01

This study serves as a baseline characterization of indoor and outdoor air quality in a remote northern indigenous community prior to the start of a major nearby mining operation, including measurements of nanoparticles, which has never been performed in this context before. We performed aerosol sample collection and real-time aerosol measurements at six different locations at the Cree First Nation of Waswanipi and the Montviel campsite, located 45 km west of the Cree First Nation of Waswanipi, in the south of the Nord-du-Québec region. High concentrations of airborne nanoparticles (up to 3.98 × 10 4  ± 8.9 × 10 3  cm -3 at 64.9-nm midpoint particle diameter) and fine particles (up to 1.99 × 10 3  ± 1.6 × 10 2  cm -3 at 0.3-μm midpoint particle diameter) were measured inside a residential home, where we did not find any ventilation or air filtration systems. The most abundant particle sizes by mass were between 0.19 and 0.55 μm. The maximum concentration of analyzed heavy metals was detected at the d 50 cut-off particle size of 0.31 μm; and the most abundant heavy metals in the aerosol samples were Al, Ba, Zn, Cu, Hg, and Pb. We concluded that the sources of the relatively high indoor particle concentrations were likely laundry machines and cooking emissions in the absence of a sufficient ventilation system. However, the chemical composition of particles resulting from mining activities is expected to be different from that of the aerosol particles from indoor sources. Installation and proper maintenance of sufficient ventilation and air filtration systems may reduce the total burden of disease from outdoor and indoor air pollution and remediate infiltrated indoor particulate pollution from the mining sources as well.

Using a passive air sampler to monitor air-soil exchange of organochlorine pesticides in the pasture of the central Tibetan Plateau.

Science.gov (United States)

Wang, Chuanfei; Wang, Xiaoping; Ren, Jiao; Gong, Ping; Yao, Tandong

2017-02-15

Air-soil exchange is a key process controlling the fate of persistent organic pollutants (POPs). However, the "sink effect" of soil for POPs in Tibetan pasture has not been clear. In NamCo, in the central Tibetan Plateau (TP) where the land is covered by grass, a modified passive air sampler (PAS) (thickness: 2cm) was tested. Using the PAS, the atmospheric gaseous phase organochlorine pesticides (OCPs) at 11 heights from close-to-surface (2cm) to 200cm above ground, in summer and in winter, were measured. Concentrations of OCPs in summer were higher than those in winter. Both in summer and winter, atmospheric concentrations of OCPs decreased with decreasing height from 200 to 2cm, indicating that OCPs were being deposited from air to soil. Air deposition of OCPs was possibly driven by wind speed. Furthermore, based on air OCPs at 0-3cm near the surface, the interface exchange of OCPs between air and soil was studied by the fugacity method. The results showed that pastural soil in the TP was a "sink" of OCPs even in summer. The mean deposition fluxes of α-HCH, γ-HCH and o,p'-DDT were 0.72, 0.24 and 0.54pg/h/m 2 , respectively, and it was estimated that the level of these pollutants in the soil will double every 24, 66 and 206years, respectively. This study will contribute to the further understanding of global cycling of POPs in different land covers. Copyright © 2016 Elsevier B.V. All rights reserved.

Numerical simulation of two-phase slug flow with liquid carryover in different diameter ratio T-junction

Science.gov (United States)

Pao, W.; Hon, L.; Saieed, A.; Ban, S.

2017-10-01

A smaller diameter conduit pointing at 12 o’clock position is typically hot-tapped to a horizontal laying production header in offshore platform to tap produced gas for downstream process train. This geometric feature is commonly known as T-junction. The nature of multiphase fluid splitting at the T-junction is a major operational challenge due to unpredictable production environment. Often, excessive liquid carryover occurs in the T-junction, leading to complete platform trip and halt production. This is because the downstream process train is not designed to handle excessive liquid. The objective of this research is to quantify the effect of different diameter ratio on phase separation efficiency in T-junction. The liquid carryover is modelled as two-phase air-water flow using Eulerian Mixture Model coupled with Volume of Fluid Method to mimic the slug flow in the main pipe. The focus in this paper is 0.0254 m (1 inch) diameter horizontal main arm and vertical branch arm with diameter ratio of 1.0, 0.5 and 0.3. The present research narrowed the investigation to only slug flow regime using Baker’s map as reference. The investigation found that, contrary to common believe, smaller diameter ratio T-junction perform worse than larger diameter ratio T-junction.

Effect of diameter and axial location on upward gas–liquid two-phase flow patterns in intermediate-scale vertical tubes

International Nuclear Information System (INIS)

Ansari, M.R.; Azadi, R.

2016-01-01

Highlights: • A vertical two-phase flow system is manufactured to study flow behavior adiabatically. • Two test sections are studied with inner diameters of 40 mm and 70 mm at two locations. • Flow pattern maps are presented for both tubes. • Effects of tube diameter and heights on pattern transition boundaries are investigated. • Three sub-patterns bubbly flow and two types of slug pattern are recognized. - Abstract: In the present research, a two-phase flow system is designed, manufactured, assembled and adjusted to study two-phase flow behavior isothermally. Test sections are tubes standing in vertical position and are made of transparent acrylic with inner diameters of 40 mm and 70 mm. Two axial locations of 1.73 m and 3.22 m are chosen for data acquisition. Flow pattern maps are presented for both tubes. Effects of tube diameter and axial location on pattern transition boundaries are investigated. Air and water are chosen as working fluids. The range of air and water superficial velocities are 0.054–9.654 m/s and 0.015–0.877 m/s for the 40 mm diameter tube, but these values are 0.038–20.44 m/s and 0.036–1.530 m/s for 70 mm diameter tube. The results show that for both tubes, increasing axial location does not affect flow transition boundaries significantly. However, slug pattern region shrinks considerably by changing tube diameter from 40 mm to 70 mm. Using image processing techniques, recorded high speed movies were investigated accurately. As a result, bubbly flow in the 40 mm tube can be divided into three sub-patterns as dispersed, agitated and agglomerated bubbly. Also, two types of slug pattern are also recognized in the same tube diameter which are called small and large slugs. Semi-annular flow is observed as an independent pattern in the 70 mm tube that does not behave as known churn or annular patterns.

Significant OH production under surface cleaning and air cleaning conditions: Impact on indoor air quality.

Science.gov (United States)

Carslaw, N; Fletcher, L; Heard, D; Ingham, T; Walker, H

2017-11-01

We report measurements of hydroxyl (OH) and hydroperoxy (HO 2 ) radicals made by laser-induced fluorescence spectroscopy in a computer classroom (i) in the absence of indoor activities (ii) during desk cleaning with a limonene-containing cleaner (iii) during operation of a commercially available "air cleaning" device. In the unmanipulated environment, the one-minute averaged OH concentration remained close to or below the limit of detection (6.5×10 5  molecule cm -3 ), whilst that of HO 2 was 1.3×10 7  molecule cm -3 . These concentrations increased to ~4×10 6 and 4×10 8  molecule cm -3 , respectively during desk cleaning. During operation of the air cleaning device, OH and HO 2 concentrations reached ~2×10 7 and ~6×10 8  molecule cm -3 respectively. The potential of these OH concentrations to initiate chemical processing is explored using a detailed chemical model for indoor air (the INDCM). The model can reproduce the measured OH and HO 2 concentrations to within 50% and often within a few % and demonstrates that the resulting secondary chemistry varies with the cleaning activity. Whilst terpene reaction products dominate the product composition following surface cleaning, those from aromatics and other VOCs are much more important during the use of the air cleaning device. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

An alpha particle detector based on a GPS mosaic scintillator plate for continuous air monitoring in plutonium handling facilities

International Nuclear Information System (INIS)

Kaneko, Junichi H.; Izaki, Kenji; Toui, Kouhei; Shimaoka, Takehiro; Morishita, Yuki; Tsubota, Youichi; Higuchi, Mikio

2016-01-01

An alpha particle detector was developed for continuous air monitoring of radioactive contamination in working chambers at plutonium handling facilities. A 5-cm-square Gd 2 Si 2 O 7 :Ce (cerium-doped gadolinium pyro-silicate, GPS:Ce) mosaic scintillator plate for alpha particle measurements was fabricated from GPS single-crystal grains of around 550 μm diameter; the GPS grains were made of a GPS polycrystalline body grown using a top seeded solution method. The scintillator layer thickness was approximately 100 μm. The surface filling rate of the GPS grains was ca. 62%. To suppress the influence of non-uniformity of pulse heights of a photomultiplier tube, a central part of ∅ 40 mm of a 76-mm-diameter photomultiplier tube was used. In addition, 3 mm thick high-transmission glass was used as a substrate of the scintillator plate. The detector achieved energy resolution of 13% for 5.5 MeV alpha particles, detection efficiency of 61% and a radon progeny nuclide reduction ratio of 64.5%. A new alpha particle detector was developed to achieve a high radon progeny nuclide reduction ratio approaching that of a silicon semiconductor detector, with high resistance to electromagnetic noise and corrosion. - Highlights: • An alpha particle detector was developed for continuous air monitoring. • The detector comprises a mosaic scintillator plate and a photomultiplier tube. • A 5-cm-square GPS mosaic scintillator plate was fabricated. • Its respective energy resolution and detection efficiency were 13 and 61%. • The radon progeny nuclide reduction ratio of the developed detector was 64.5%.

Experimental investigation of pressure and blockage effects on combustion limits in H2-air-steam mixtures

International Nuclear Information System (INIS)

Sherman, M.P.; Berman, M.; Beyer, R.F.

1993-06-01

Experiments with hydrogen-air-steam mixtures, such as those found within a containment system following a reactor accident, were conducted in the Heated Detonation Tube (43 cm diameter and 12 m long) to determine the region of benign combustion; i.e., the region between the flammability limits and the deflagration-to-detonation transition limits. Obstacles were used to accelerate the flame; these include 30% blockage ratio annular rings, and alternate rings and disks of 60% blockage ratio. The initial conditions were 110 degree C and one or three atmospheres pressure. A benign burning region exists for rich mixtures, but is generally smaller than for lean mixtures. Effects of the different obstacles and of the different pressures are discussed

Experimental investigation on the performance of an impinging jet solar air heater

Directory of Open Access Journals (Sweden)

T. Rajaseenivasan

2017-03-01

Full Text Available Investigation on an impinging jet solar air heater is performed and reported in this work. The air is supplied through an impinging jet pipe which contains the nozzles to distribute the air in the solar air heater. The air is released from the jet strikes the absorber plate which increases the heat transfer rate by creating turbulent flow in the collector. This study is focused on the parameters that affect the heat transfer characteristics and compared with conventional solar air heater. The system is examined by varying the angle of attack (0°, 10°, 20°, 30°, 60° and 90° and the nozzle diameter (3 mm, 5 mm and 7 mm in the air mass flow rate range of 0.012–0.016 kg/s. The study revealed that the highest performance is achieved with the 30° angle of attack, and the lowest performance is recorded with the 0°. The reduction in jet diameter increases the pressure loss in the collector. The better system performance is observed with the 5 mm diameter hole. The maximum thermal enhancement factor of 2.19 and efficiency of 55.8% are reached with the flow rate of 0.016 kg/s.

The influence of prosthesis diameter in stapes surgery: a meta-analysis and systematic review of the literature.

Science.gov (United States)

Laske, Roman D; Röösli, Christof; Chatzimichalis, Michail Vasileios; Sim, Jae Hoon; Huber, Alexander M

2011-06-01

To analyze the influence of stapes prosthesis diameter on postoperative hearing results after stapedotomy without interposition in otosclerotic patients. PubMed search from 1970 to 2009 using the key words stapedotomy or stapedectomy or otosclerosis or stapesplasty. Inclusion criteria to select articles and patient groups for meta-analysis and statistical analyses were as follows: otosclerosis as diagnosis, clear description of technique and prosthesis size, calibrated stapedotomy, and complete report of functional results. Five controlled studies were found analyzing the influence of prosthesis diameter and reporting the results in a comparable way for meta-analysis (n = 590). Sixty-two studies not analyzing the influence of prosthesis diameter contained comparable subgroups with a total of 9,536 cases. These cases were pooled according to their diameter (0.3, 0.4, 0.5, 0.6,and 0.8 mm). The results of air conduction, bone conduction, air-bone gap (ABG), and success rate (closure of the ABG within 10 dB as percentage of the total cases) for all groups and frequency-specific ABG results were gathered. Furthermore, 12 clinical and experimental studies were reviewed that did not contribute to the statistical analysis. A meta-analysis performed for success rate of the 5 controlled studies showed favorable results for 0.6-mm over 0.4-mm prostheses (success rate, 67% versus 58%, p = 0.05). In the statistical analysis of the pooled data, the 0.6-mm prosthesis showed better results compared with 0.4 mm (p prosthesis in the high frequencies. There was no difference in postoperative change of bone conduction in the 0.6- and 0.4-mm groups. Statistically significant results could not be assessed for other prosthesis diameters because of the small number of cases reported. A 0.6-mm diameter piston prosthesis is associated with significantly better results than a 0.4-mm prosthesis and should be used if the surgical conditions allow it.

Tree diameter at breast height in relation to stump diameter by species group

Science.gov (United States)

Arthur G. Horn; Richard C. Keller

1957-01-01

A stump tally is one method of determining the volume of timber previously removed from an area in a logging operation. To estimate volume of standing timber from stumps, foresters must first know the relationship between stump diameters and tree diameters at breast height (d.b.h.).

Separation and recovery of Cm from Cm-Pu mixed oxide samples containing Am impurity

International Nuclear Information System (INIS)

Hirokazu Hayashi; Hiromichi Hagiya; Mitsuo Akabori; Yasuji Morita; Kazuo Minato

2013-01-01

Curium was separated and recovered as an oxalate from a Cm-Pu mixed oxide which had been a 244 Cm oxide sample prepared more than 40 years ago and the ratio of 244 Cm to 240 Pu was estimated to 0.2:0.8. Radiochemical analyses of the solution prepared by dissolving the Cm-Pu mixed oxide in nitric acid revealed that the oxide contained about 1 at% of 243 Am impurity. To obtain high purity curium solution, plutonium and americium were removed from the solution by an anion exchange method and by chromatographic separation using tertiary pyridine resin embedded in silica beads with nitric acid/methanol mixed solution, respectively. Curium oxalate, a precursor compound of curium oxide, was prepared from the purified curium solution. 11.9 mg of Cm oxalate having some amounts of impurities, which are 243 Am (5.4 at%) and 240 Pu (0.3 at%) was obtained without Am removal procedure. Meanwhile, 12.0 mg of Cm oxalate (99.8 at% over actinides) was obtained with the procedure including Am removals. Both of the obtained Cm oxalate sample were supplied for the syntheses and measurements of the thermochemical properties of curium compounds. (author)

344 cm x 86 cm low mass vacuum window

International Nuclear Information System (INIS)

Reimers, R.M.; Porter, J.; Meneghetti, J.; Wilde, S.; Miller, R.

1983-08-01

The LBL Heavy Ion Spectrometer System (HISS) superconducting magnet contains a 1 m x 3.45 m x 2 m vacuum tank in its gap. A full aperture thin window was needed to minimize background as the products of nuclear collisions move from upstream targets to downstream detectors. Six windows were built and tested in the development process. The final window's unsupported area is 3m 2 with a 25 cm inward deflection. The design consists of a .11 mm Nylon/aluminum/polypropylene laminate as a gas seal and .55 mm woven aramid fiber for strength. Total mass is 80 milligrams per cm 2 . Development depended heavily on past experience and testing. Safety considerations are discussed

Sonographic study about differential diagnosis between acute appendicitis and non-appendicitis in appendices of borderline diameter

International Nuclear Information System (INIS)

Chung, Hwan Hoon; Kim, Yun Hwan; Kim, Hong Won; Park, Seung Cheol; Lee, Eun Jeong; Chung, Kyoo Byung; Suh, Won Hyuck

2000-01-01

To find out the sonographic criteria which can be effectively used to differentiate acute appendicitis from non-appendicitis in patients with appendices with borderline diameter(5-8 mm). Sixteen patients diagnosed as acute appendicitis, another 16 patients diagnosed as non-appendicitis were included in this study. They complained of RLQ pain and their appendices measured 5-8 mm in diameter on sonogram. Features such as appendiceal wall thickness, presence or absence of air in appendiceal lumen, movability of tip of the appendix, compressibility of the appendix were evaluated on gray-scale sonogram and thereafter, presence or absence of color flow in the wall of the appendix was evaluated on color Doppler sonogram. Thickness of appendiceal wall is 2.98 ± 0.77 mm in acute appendicitis group and 1.73 ± 0.44 mm in non-appendicitis group (p<0.05). When 2.5 mm thickness of appendiceal wall is applied for diagnosis of acute appendicitis, sensitivity is 81.3%, specificity is 87.5% and accuracy is 84.4%. With absence of air in appendiceal lumen, sensitivity is 93.8%, specificity is 68.8% and accuracy is 81.3%. With absence of movability of appendiceal tip, sensitivity is 87.5%, specificity is 50% and accuracy is 68.8%. With absence of compressibility of the appendix, sensitivity is 100%, specificity is 31.3% and accuracy is 65.6%. With color flow in appendiceal wall, sensitivity is 81.3%, specificity is 62.5% and accuracy is 71.9%. The above mentioned criteria show statistically significant difference between acute appendicitis and non-appendicitis groups (p<0.05). When the diameter of the appendix measures 5-8 mm on sonogram, evaluation of thickness of appendiceal wall, air in appendiceal lumen, movability of tip, compressibility and color flow in the wall will be helpful to diagnose the acute appendicitis with confidence.

Efektivitas Penambahan Karbon Aktif Cangkang Kelapa Sawit (Elaeis Guineensis dalam Proses Filtrasi Air Sumur

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Muhammad Fadhillah

2016-05-01

Full Text Available Dampak dari pencemaran air dapat menyebabkan terjadinya ketidakseimbangan ekosistem dan dapat sebagai pembawa penyakit menular. Oleh karena itu perlu dilakukan penjernihan terhadap air sebelum digunakan untuk meningkatkan kualitas air.  Salah satu  yang dapat digunakan untuk penjernihan air adalah arang aktif cangkang kelapa sawit (Elaeis guineensis. Tujuan penelitian ini adalah: Untuk mengetahui efektifitas penambahan arang aktif cangkang kelapa sawit  dalam proses  filtrasi terhadap karakter fisik (kekeruhan, Ph, bau dan rasa air sumur. Penelitian ini bersifat eksperimen dengan menggunakan Rancangan Acak Lengkap (RAL. Filtrasi air sumur dilakukan dengan 4 perlakuan  dan 3 kali ulangan yaitu: 1. tanpa melewati saringan pasir (kontrol, 2. melewati saringan pasir tanpa arang aktif cangkang kelapa sawit, 3. melewati saringan pasir dengan penambahan arang aktif cangkang kelapa sawit  dengan ketebalan 10 cm, dan 4. ketebalan 15 cm. One way ANOVA digunakan dalam analisis data. Analisa kekeruhan adalah 100,0; 50,5; 40,4; dan 47,5 berturut-turut untuk kontrol, tanpa arang aktif, dengan arang aktif 10 cm dan dengan arang aktif 15 cm. Hasil uji menunjukkan perbedaan yang bermakna antara kekeruhan air kontrol dengan kekeruhan dari perlakuan lainnya. pH air < 7 menjadi 8,99. Analisa bau dan rasa didapatkan  air yang melewati proses filtrasi dengan penambahan arang aktif menghilangkan bau dan rasa pada air tersebut. Penambahan arang aktif cangkang kelapa sawit dengan ketebalan 10 cm cukup efektif dalam proses filtrasi air sumur dan dapat memperbaiki kualitas fisik air.

A parametric study of microjet assisted methane/air turbulent flames

International Nuclear Information System (INIS)

Chouaieb, Sirine; Kriaa, Wassim; Mhiri, Hatem; Bournot, Philippe

2017-01-01

Highlights: • Microjet assisted methane/air turbulent flames are numerically investigated. • A parametric study concerning the microjet velocity and diameter is carried out. • Previous validation of temperature, mixture fraction and soot is enhanced. • Mixing and soot emission are controlled for higher velocities and lower diameters. • Soot production is reduced by 94% for a microjet velocity equal to 1 m/s. - Abstract: A parametric study of microjet assisted methane/air turbulent flames characteristics is numerically investigated. The Presumed Probability Density Function model and the Discrete Ordinates model are respectively considered for combustion and radiation modeling. The k-epsilon Standard model with Pope Correction is adopted as a turbulence closure model. The two step Tesner model is used to quantify the soot particle production in the flame configuration. Comparison with our previous work using the k-epsilon Realizable model shows that the k-epsilon Standard model with Pope Correction ensures better predictions. The microjet velocity and diameter effects on thermal field, mixing process and soot emission are then discussed. Numerical findings show that the microjet can be used as an efficient tool controlling methane/air turbulent flames. On the one hand, it is shown that the microjet creates an inner flame in the vicinity of the central nozzle exit but does not globally alter the methane/air flame shape. On the other hand, mixing process can be enhanced for high microjet Reynolds number either by increasing the microjet velocity or by decreasing its nozzle diameter for a constant microjet mass flow rate. Soot production can be consequently reduced for low microjet diameter and high velocity values.

Study on the wide-angle Michelson interferometer with large air gap.

Science.gov (United States)

Gao, Haiyang; Tang, Yuanhe; Hua, Dengxin; Liu, Hanchen

2011-10-10

A wide-angle Michelson interferometer with large air gap is proposed to effectively reduce the size of the glass arms and constraint on material. It provides a novel and practical instrument for ground based wind measurement of the upper atmosphere. The field widening conditions for the large air gap are calculated in theory. For the five spectral lines of 557.7 nm, 630.0 nm, 732.0 nm, 834.6 nm, and 865.7 nm, the optimal results under ideal condition are obtained with air gaps of 1.0 cm, 1.5 cm, and 2.0 cm, respectively. With the fixed optical path difference (OPD) of 7.495 cm, three pairs of glass arms are optimized. The pair with length of 1.5 cm for air gap, 5.765 cm for H-ZF12, and 2.956 cm for H-ZLaF54, has better effect of field widening than the other two pairs and its OPD variation is only within 0.30 wavelengths at incident angle of 3°. For developing a more practical wide-angle Michelson interferometer, the H-K9L glass with size of 4.445 cm is employed as the arm material of solid interferometer. The experiment for field of view of 3° is designed and the data processing and analysis for 60 images show the agreement between experimental results and theoretical simulation. The OPD variations are only within 0.27 wavelengths for image edge. The feasibility and practicality of the wide-angle Michelson interferometer with large air gap is proved by means of theory and experiment. © 2011 Optical Society of America

Simulation of 1.5-mm-thick and 15-cm-diameter gated silicon drift X-ray detector operated with a single high-voltage source

Science.gov (United States)

Matsuura, Hideharu

2015-04-01

High-resolution silicon X-ray detectors with a large active area are required for effectively detecting traces of hazardous elements in food and soil through the measurement of the energies and counts of X-ray fluorescence photons radially emitted from these elements. The thicknesses and areas of commercial silicon drift detectors (SDDs) are up to 0.5 mm and 1.5 cm2, respectively. We describe 1.5-mm-thick gated SDDs (GSDDs) that can detect photons with energies up to 50 keV. We simulated the electric potential distributions in GSDDs with a Si thickness of 1.5 mm and areas from 0.18 to 168 cm2 at a single high reverse bias. The area of a GSDD could be enlarged simply by increasing all the gate widths by the same multiple, and the capacitance of the GSDD remained small and its X-ray count rate remained high.

Characteristics of a commercial Hi-pSi detector for dosimetry of stereotactic collimators with very small diameters

International Nuclear Information System (INIS)

Foerster, U.; Grebe, G.; Pfaender, M.

2002-01-01

Background: Conformal stereotactic radiosurgery and radiotherapy with linear accelerators and hole collimators yield a dose concentration in the target volume by rotation of the gantry. For small target volumes collimators with isocentre diameters of 4-45 mm are used. In this paper dosimetric measurements with a commercial high doped p-type silicon detector are demonstrated and compared to measurements with diamond detector and ionisation chamber. Material and Methods: The properties of the silicon detector SFD trademark from Scanditronix were investigated with the radiation of a Gammatron trademark S and a Varian 2100 CD trademark at 6 MV. The results were compared with those of a calibrated ionisation chamber (0.3 cm 3 ) and a diamond detector. Measurements and Results: At the beginning the reproducibility of the registered dose and dose rate and the temperature dependence of the Si-detector were investigated at the Gammatron S. For the comparison the absorbed dose was measured with the ionisation chamber in air. The sensitivity decreases slightly with dose and dose rate. After a period of several days without radiation again higher doses were registered. The temperature dependence causes deviations of 0.25%/K. The signal-to-noise ratio and the spatial resolution were investigated with the linear accelerator. The signal-to-noise ratio is clearly lower compared with that of the diamond detector, whereas the resolution is nearly the same. Conclusions: The Si-detector is qualified for dosimetry of very small fields because of the insignificant dose and dose rate dependence and in spite of some disadvantages regarding dosimetric properties compared with the diamond detector. The advantage is the availability and the cost. Measurement with ionisation chambers are not useful for collimator diameters below 20 mm. (orig.) [de

Variation and balance of positive air ion concentrations in a boreal forest

Directory of Open Access Journals (Sweden)

U. Hõrrak

2008-02-01

hypothesis of the conversion of ions into particles in the process of ion-induced nucleation was not proved. The estimated average ionization rate of the air at the Hyytiälä station in early spring, when the ground was partly covered with snow, was about 6 ion pairs cm⁻³ s⁻¹. The study of the charging state of nanometer aerosol particles (diameter 2.5–8 nm in the atmosphere revealed a strong correlation (correlation coefficient 88% between the concentrations of particles neutralized in the aerosol spectrometer and naturally positively charged particles (air ions during nucleation bursts. The charged fraction of particles varied from 3% to 6% in accordance with the hypothesis that the particles are quasi-steady state charged.

Status of air kerma and absorbed dose standards in India

International Nuclear Information System (INIS)

Vijayam, M.; Ramanathan, G.; Patki, V.S.; Soman, A.T.; Shigwan, J.B.; Vinatha, S.P.; Jadhavgaonkar, P.S.; Kadam, V.D.; Shaha, V.V.; Abani, M.C.

2002-01-01

Full text: The Radiation Safety Systems Division of Bhabha Atomic Research Centre, India maintains Primary and Secondary Standards of various parameters of radiation measurements and provides calibration services to various users of radiation in the country. This is an apex laboratory in India and plays a pivotal role in ensuring accurate radiological measurements. The laboratory coordinates national intercomparisons of radiation measurements to maintain their uniformity and traceability and is linked through various programmes with the other International organizations such as Bureau Internationale des Poids et Mesures (BIPM) Paris, International Atomic Energy Agency (IAEA) Vienna, Asia Pacific Metrology Programme (APMP) Taiwan. It is the recognized Regional Secondary Standards Dosimetry Laboratory (SSDL) of IAEA/WHO (World Health Organisation). This paper brings out the status of various primary and secondary standards for radiological measurements maintained at BARC. 1. Primary Exposure/Air-kerma standard at Co-60 energy (therapy level): The primary standard for exposure/ air-kerma measurements maintained at BARC is a graphite cavity chamber of volume 4.362 cc with an internal diameter of 1.8 cm, internal height of 1.78 cm and wall thickness of 704.3mg/cm 2 . Correction factors for the difference between electron stopping powers, photon mass energy absorption coefficients of air and graphite wall, correction for recombination, radiation field non-uniformity, stem scatter and polarity effect are applied and the maximum overall uncertainty in the realisation of exposure/air-kerma is around ±1%. This standard has been intercompared with IAEA and BIPM through transfer standard and the agreement in the results are better than ±1%. An intercomparison under the APMP programme is to be held during May, 2002. 2. Primary Exposure/Air-kerma standard at protection and brachytherapy level: A set of three spherical graphite-walled cavity chambers of different air

Maximum Diameter Measurements of Aortic Aneurysms on Axial CT Images After Endovascular Aneurysm Repair: Sufficient for Follow-up?

International Nuclear Information System (INIS)

Baumueller, Stephan; Nguyen, Thi Dan Linh; Goetti, Robert Paul; Lachat, Mario; Seifert, Burkhardt; Pfammatter, Thomas; Frauenfelder, Thomas

2011-01-01

Purpose: To assess the accuracy of maximum diameter measurements of aortic aneurysms after endovascular aneurysm repair (EVAR) on axial computed tomographic (CT) images in comparison to maximum diameter measurements perpendicular to the intravascular centerline for follow-up by using three-dimensional (3D) volume measurements as the reference standard. Materials and Methods: Forty-nine consecutive patients (73 ± 7.5 years, range 51–88 years), who underwent EVAR of an infrarenal aortic aneurysm were retrospectively included. Two blinded readers twice independently measured the maximum aneurysm diameter on axial CT images performed at discharge, and at 1 and 2 years after intervention. The maximum diameter perpendicular to the centerline was automatically measured. Volumes of the aortic aneurysms were calculated by dedicated semiautomated 3D segmentation software (3surgery, 3mensio, the Netherlands). Changes in diameter of 0.5 cm and in volume of 10% were considered clinically significant. Intra- and interobserver agreements were calculated by intraclass correlations (ICC) in a random effects analysis of variance. The two unidimensional measurement methods were correlated to the reference standard. Results: Intra- and interobserver agreements for maximum aneurysm diameter measurements were excellent (ICC = 0.98 and ICC = 0.96, respectively). There was an excellent correlation between maximum aneurysm diameters measured on axial CT images and 3D volume measurements (r = 0.93, P < 0.001) as well as between maximum diameter measurements perpendicular to the centerline and 3D volume measurements (r = 0.93, P < 0.001). Conclusion: Measurements of maximum aneurysm diameters on axial CT images are an accurate, reliable, and robust method for follow-up after EVAR and can be used in daily routine.

Petrol contaminated groundwater treatment with air-stripper in Balassagyarmat, Hungary

International Nuclear Information System (INIS)

Szabo, Peter; Bernath, Balazs

2005-01-01

Hydrocarbon contaminated groundwater is a common environmental problem in Hungary. Leakage of underground storage tanks, pipe break or illegal tapping as well as lorry accidents can be mentioned as main reasons. MEGATERRA Ltd. elaborated, adopted and tested several groundwater clean-up methods. These methods are based on detailed survey and investigation, sampling and analysis, delineation of contaminated groundwater, risk assessment, establishment of monitoring wells, pumping tests and remediation action plan. One of these methods was implemented by MEGATERRA Ltd. in Balassagyarmat, Hungary. Contamination source was a 10 m 3 vol. simple wall underground fuel-storage tank, which had been emptied. When the remediation started in April 1998, the petrol had already been accumulated on the ground water table forming a 5-7 m wide and 10-15 m long plume being expanded to SSE-NNW direction. The area of the dissolved hydrocarbon contaminated groundwater-body was 1 000 m 2 and its concentration reached up to 30-40 mg/l TPH. The free-phase hydrocarbon layer was 10 cm thick. For the remediation of contaminated groundwater MEGATERRA Ltd. applied pump and treat method, namely groundwater pumping using extraction well, skimming of free-phase hydrocarbon, stripping of the contaminated ground water in air-stripper tower and draining of the treated groundwater into a drainage ditch. In the centre of the plume we established an extraction well with 300 mm diameter in a 500 mm borehole. Peristaltic skimmer pump was used inside the extraction well to remove the free phase petrol from the ground water surface.Because of the intense volatility of the pollutant we applied aeration (stripping) technology. The extracted contaminated groundwater was cleaned in air-stripper equipment being able to eliminate efficiently the volatile pollutants from the water. The aeration tower is a compact cylindrical shaped column with 650 mm in diameter. Its height depends on the pollutant's type The

Effect of Heating/Hydratation on Compacted Bentonite: Tests in 60-cm Long Cells

Energy Technology Data Exchange (ETDEWEB)

Villar, M. V.; Fernandez, A. M.; Martin, P. L.; Barcala, J. M.; Gomez-Espina, R.; Rivas, P.

2008-07-01

The conditions of the bentonite in an engineered barrier for high-level radioactive waste disposal have been simulated in a series of tests. Cylindrical cells with an inner length of 60 cm and a diameter of 7 cm were constructed. Inside the cells, blocks of compacted FEBEX bentonite were put one on top of the other. the bottom surface of the material was heated at 100 degree centigree and the top surface was injected with granitic water. the duration of the tests was 0.5, 1,2 and 7,6 years. The temperatures and water intake were measured during the tests and, at the end, the cells were dismounted and the dry density, water content, mineralogy, geochemistry and some hydro-mechanical properties of the clay (permeability, swelling) were measured at different positions. the values obtained are compared among them and to those of the untreated FEBEX bentonite. The study has run over for 10 years in the context of the projects FEBEX I and II and NF-PRO. (Author) 50 refs.

Effect of Heating/Hydratation on Compacted Bentonite: Tests in 60-cm Long Cells

International Nuclear Information System (INIS)

Villar, M. V.; Fernandez, A. M.; Martin, P. L.; Barcala, J. M.; Gomez-Espina, R.; Rivas, P.

2008-01-01

The conditions of the bentonite in an engineered barrier for high-level radioactive waste disposal have been simulated in a series of tests. Cylindrical cells with an inner length of 60 cm and a diameter of 7 cm were constructed. Inside the cells, blocks of compacted FEBEX bentonite were put one on top of the other. the bottom surface of the material was heated at 100 degree centigree and the top surface was injected with granitic water. the duration of the tests was 0.5, 1,2 and 7,6 years. The temperatures and water intake were measured during the tests and, at the end, the cells were dismounted and the dry density, water content, mineralogy, geochemistry and some hydro-mechanical properties of the clay (permeability, swelling) were measured at different positions. the values obtained are compared among them and to those of the untreated FEBEX bentonite. The study has run over for 10 years in the context of the projects FEBEX I and II and NF-PRO. (Author) 50 refs

An experimental study on counter current flow limitation in annular narrow gaps with large diameter

Energy Technology Data Exchange (ETDEWEB)

Park, Rae Joon; Jeong, Ji Whan; Lee, Sung Jin; Cho, Young Ro; Ha, Kwang Sun; Kim, Sang Baik; Kim, Hee Dong [Korea Atomic Energy Research Institute, Taejeon (Korea)

2002-04-01

The present study intends to carry out CCFL experiment with the same gap size as the CHFG facility and suggest an empirical correlation in order to provide basic information useful to development of an empirical critical-power correlation. The present facility consists of water accumulator tank, test section, DC pump, air regulator, valves and sensors. Air and water are used as working fluids. The experiments are carried out at the atmospheric pressure. Differential pressure between the gap ends, liquid and gas phase flow rates, temperature, lower plenum pressure are measured.Measured values are expressed in terms of Wallis' parameter using gap size as a characteristic length. There is a big difference between the present experimental results and the Koizumi et al.'s results, but the present experimental results are very similar to the Richter et al.'s results. The present results agree well with the Osakabe and Kawasaki's results. In comparison of present experiments with the Koizumi et al.'s experiments, gap thickness is similar, but the diameter of the present is bigger than that of Koizumi et al.'s experiments. In comparison of present experiments with the Richter et al.'s experiments, diameter is similar, but the gap thickness of the present is smaller than that of Richter et al.'s experiments. It is judged from these results that correlation development on CCFL to consider gap thickness is reasonable at similar condition of diameter.The developed correlation will be used to develop the CHFG model. 36 refs., 26 figs., 7 tabs. (Author)

The Relationship amongst Intervertebral Disc Vertical Diameter, Lateral Foramen Diameter and Nerve Root Impingement in Lumbar Vertebra

Directory of Open Access Journals (Sweden)

Yusof MI

2018-03-01

Full Text Available Introduction: The vertical diameter of the foramen is dependent upon the vertical diameter of the corresponding intervertebral disc. A decrease in disc vertical diameter has direct anatomic consequences to the foraminal diameter and area available for the nerve root passing through it. This study is to establish the relationship amongst the intervertebral disc vertical diameter, lateral foramen diameters and nerve root compression in the lumbar vertebra. Materials and Methods: Measurements of the study parameters were performed using sagittal MRI images. The parameters studied were: intervertebral disc vertical diameter (DVD, foraminal vertical diameter (FVD, foraminal transverse diameter (FTD and nerve root diameter (NRD of both sides. The relationship between the measured parameters were then analyzed. Results: A total of 62 MRI images were available for this study. Statistical analysis showed moderate to strong correlation between DVD and FVD at all the lumbar levels except at left L23 and L5S1 and right L3L4 and L4L5. Correlation between DVD and FTD were not significant at all lumbar levels. Regression analysis showed that a decrease of 1mm of DVD was associated with 1.3, 1.7, 3.3, 3.3 and 1.3mm reduction of FVD at L1L2, L2L3, L3L4, L4L5 and L5S1 respectively. Conclusion: Reduction of DVD was associated with reduction of FVD. However, FVD was relatively wide for the nerve root even with complete loss of DVD. FTD was much narrower than the FVD making it more likely to cause nerve root compression at the exit foramina. These anatomical details should be given consideration in treating patients with lateral canal stenosis.

Validity of using modified capillary column with larger diameter to study the Cs diffusion in local Taiwan laterite

International Nuclear Information System (INIS)

Tsing-Hai Wang; National Tsing Hua University, Hsinchu, Taiwan; Wen-Chun Yeh; Shih-Chin Tsai; Yi-Lin Jan; Shi-Ping Teng

2008-01-01

We have examined the working diameter of capillary columns with diameter of 5, 7, 10 and 20 mm. These modified capillary columns were carefully filled with local Taiwan laterite (LTL). The porosity and density of these packed columns was 0.51±0.02 g/g and 1.27±0.05 g/cm 3 , respectively. The diffusion experiments were then carried out in synthetic groundwater with Cs loading of 0.1mM at room temperature. Experimental results have shown that the diffusion profiles of modified capillary columns fit Fick's second law very well. This result revealed that the working diameter of a capillary column can be expanded to at least to 20 mm without affecting the validity of the derived diffusion coefficients. Among these columns, the ones with 5 mm diameter show the most consistent results of the derived K d , apparent and effective diffusion coefficients. Although the derived distribution and effective diffusion coefficients slightly decrease as the diameter of these columns increases due to the increase of the solid/liquid ratio. These values are still informative of the Cs diffusion in local Taiwan laterite. Moreover, our results clearly demonstrate the potential of using 'modified capillary method' to study the diffusion behaviors of concerned radionuclide because columns with large diameter enable the filling with more versatile geological substances. (author)

acceleration observed in an audio air gas discharge

International Nuclear Information System (INIS)

Ragheb, M.S.

2010-01-01

an audio air gas discharge enclosed in a pyrex glass of 34 mm diameter and 25 cm long , lead to trace the occurrence of an unusual phenomenon. injected relative huge light spots of intense brightness, distributed regularly on the contour and in the center of one of the discharge electrodes, are observed. very high heat is pronounced on both electrodes, while, one of them is higher than the other it attains 660 degree C in 3-4 minutes. series of photographs and registered video films define and clarify the sequence of events that describe the observed phenomenon. the plasma is created by applying an audio power through the electrodes of an air gas discharge of 10 khz and up to 500 watts power supply. the discharge voltage is up to 900 volts: the discharge current flowing through the plasma attains 360 mA. it is found that the discharge system must attain its optimal working conditions in order to produce the amazing phenomena. the obtained plasma is classified as the maximum conditions borders of a γ-discharge type. at these conditions, the corresponding maximum electron temperature and density are 16 eV and 10 15 cm -3 respectively . the observation system succeeded to reveal and to clarify the sequence of the phenomenon events. in addition, by means of the scanning electron microscope and the energy dispersive x- ray systems, the effects on the electrodes surface are investigated and analyzed. the optical observations, in conjunction with the micrograph and surface microanalysis,demonstrate the collision occurrence, of powered agglomerations groups, to the electrode surface. detailed interpretation of that phenomenon suggests a molecular acceleration gaining their energy from the formed plasma due to optimal discharge working conditions. as a consequence, due to the ions agglomerates size this procedure could be considered as a mesoscopic acceleration technique.

EGG QUALITY OF CREOLE HENS REARED IN THE BACKYARD

Directory of Open Access Journals (Sweden)

Aureliano Juárez-Caratachea

2009-09-01

Full Text Available The egg quality from Creole backyard hens was determined by collecting samples from 11 municipalities from the central area of Michoacan State, Mexico. It was measured: egg weight (EW, longitude diameter (LD of the egg, transversal diameter (TD of the egg, shell weight (SW, shell thickness (ST, shell index (SI, white diameter (WD, yolk diameter (YD, white high (WH, yolk high (YH, air chamber high (ACH and Haugh units (HU. The averages obtained were: EW 50.7 g; LD 5.6 cm; TD 4.2 cm; SW 4.5 g.; ST 0.28 mm; SI 8.9 %; WD 10.0 cm; YD 4.5 cm; WH 6.3 mm; YH 1.6 cm; ACH 5.4 mm; HU 73.4, YP 12.1. In conclusion, the eggs of backyard hens were smaller than commercial eggs. However, the internal quality indicators suggested that backyard hen eggs have similar quality to that of commercial hens.

Two-phase fluid flow measurements in small diameter channels using real-time neutron radiography

International Nuclear Information System (INIS)

Carlisle, B.S.; Johns, R.C.; Hassan, Y.A.

2004-01-01

A series of real-time, neutron radiography, experiments are ongoing at the Texas A and M Nuclear Science Center Reactor (NSCR). These tests determine the resolving capabilities for radiographic imaging of two phase water and air flow regimes through small diameter flow channels. Though both film and video radiographic imaging is available, the real-time video imaging was selected to capture the dynamic flow patterns with results that continue to improve. (author)

Effects of Diameter on Initial Stiffness of P-Y Curves for Large-Diameter Piles in Sand

DEFF Research Database (Denmark)

Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Augustesen, Anders Hust

2010-01-01

is developed for slender piles with diameters up to approximately 2.0 m. Hence, the method is not validated for piles with diameters of 4–6 m. The aim of the paper is to extend the p-y curve method to large-diameter non-slender piles in sand by considering the effects of the pile diameter on the soil-pile...... interaction. Hence, a modified expression for the p-y curves for statically loaded piles in sand is proposed in which the initial slope of the p-y curves depends on the depth below the soil surface, the pile diameter and the internal angle of friction. The evaluation is based on three-dimensional numerical...... analyses by means of the commercial program FLAC3D incorporating a Mohr-Coulomb failure criterion. The numerical model is validated with laboratory tests in a pressure tank at Aalborg University....

Air ions and aerosol science

International Nuclear Information System (INIS)

Tammet, H.

1996-01-01

Collaboration between Gas Discharge and Plasma Physics, Atmospheric Electricity, and Aerosol Science is a factor of success in the research of air ions. The concept of air ion as of any carrier of electrical current through the air is inherent to Atmospheric Electricity under which a considerable statistical information about the air ion mobility spectrum is collected. A new model of air ion size-mobility correlation has been developed proceeding from Aerosol Science and joining the methods of neighboring research fields. The predicted temperature variation of the mobility disagrees with the commonly used Langevin rule for the reduction of air ion mobilities to the standard conditions. Concurrent errors are too big to be neglected in applications. The critical diameter distinguishing cluster ions and charged aerosol particles has been estimated to be 1.4 endash 1.8 nm. copyright 1996 American Institute of Physics

Fission tracks diameters in glasses

International Nuclear Information System (INIS)

Garzon Ruiperez, L.; Veiguela, J.

1974-01-01

Standard glass microscope slides have been irradiated with fission fragments from the uranium. The etching track conditions have been the same for the series, having changed the etching time only for each specimen. For each glass, a minimum of 250 measurements of the tracks diameters have been made, the distributions of which are the bimodal type. Diameters-etching dependence with time is roughly lineal. Energy determinations have been made with the help of the diameters-energy relations. The calculated values agree very well with the know ones. (author) [es

Strength of smoke-free air laws and indoor air quality.

Science.gov (United States)

Lee, Kiyoung; Hahn, Ellen J; Robertson, Heather E; Lee, Seongjik; Vogel, Suzann L; Travers, Mark J

2009-04-01

Smoke-free air laws have been implemented in many Kentucky communities to protect the public from the harmful effects of secondhand smoke exposure. The impact of different strengths of smoke-free air laws on indoor air quality was assessed. Indoor air quality in hospitality venues was assessed in seven communities before and after comprehensive smoke-free air laws and in two communities only after partial smoke-free air laws. One community was measured three times: before any smoke-free air law, after the initial partial law, and after the law was strengthened to cover all workplaces and public places with few exemptions. Real-time measurements of particulate matters with 2.5 mum aerodynamic diameter or smaller (PM(2.5)) were obtained. When comprehensive smoke-free air laws were implemented, indoor PM(2.5) concentrations decreased significantly from 161 to 20 microg/m3. In one community that implemented a comprehensive smoke-free law after initially passing a partial law, indoor PM(2.5) concentrations were 304 microg/m3 before the law, 338 microg/m3 after the partial law, and 9 microg/m3 after the comprehensive law. The study clearly demonstrated that partial smoke-free air laws do not improve indoor air quality. A significant linear trend indicated that PM(2.5) levels in the establishments decreased with fewer numbers of burning cigarettes. Only comprehensive smoke-free air laws are effective in reducing indoor air pollution from secondhand tobacco smoke.

Diameter-dependent coloration of silver nanowires

International Nuclear Information System (INIS)

Stewart, Mindy S; Qiu Chao; Jiang Chaoyang; Kattumenu, Ramesh; Singamaneni, Srikanth

2011-01-01

Silver nanowires were synthesized with a green method and characterized with microscopic and diffractometric methods. The correlation between the colors of the nanowires deposited on a solid substrate and their diameters was explored. Silver nanowires that appear similar in color in the optical micrographs have very similar diameters as determined by atomic force microscopy. We have summarized the diameter-dependent coloration for these silver nanowires. An optical interference model was applied to explain such correlation. In addition, microreflectance spectra were obtained from individual nanowires and the observed spectra can be explained with the optical interference theory. This work provides a cheap, quick and simple screening method for studying the diameter distribution of silver nanowires, as well as the diameter variations of individual silver nanowires, without complicated sample preparation.

Investigations on Important Properties of the 10 cm x 10 cm GEM Prototype

CERN Document Server

Saenboonruang, Kiadtisak; Kulasri, Kittipong; Ritthirong, Anawat

2015-01-01

The Gas Electron Multiplier (GEM) detector is one of promising particle and radiation detectors that has been improved greatly from previous gas detectors. The improvement includes better spatial resolutions, higher detection rate capabilities, and flexibilities in designs. In particular, the 10 cm x 10 cm GEM prototype is designed and provided by the Gas Detectors Development group (GDD) at CERN, Switzerland. With its simplicity in operations and designs, while still maintaining high qualities, the GEM prototype is suitable for both start-up and advanced researches. This article aims to report the investigations on some important properties of the 10 cm x 10 cm GEM detector using current measurement and signal counting. Results have shown that gains of the GEM prototype exponentially increase as voltage supplied to the detector increases, while the detector reaches full efficiency (plateau region) when the voltage is greater than 4100 V. In terms of signal sharing between X and Y strips of the readout, X str...

Effects of electron irradiation and temperature on 1 ohm-cm and 10 ohm-cm silicon solar cells

Science.gov (United States)

Nicoletta, C. A.

1973-01-01

One OHM-cm and 10 OHM-cm silicon solar cells were exposed to 1.0 MeV electrons at a fixed flux of 10 to the 11th power e/sq cm/sec and fluences of 10 to the 13th power, 10 to the 14th power and 10 to the 15th power e/sq.cm. 1-V curves of the cells were made at room temperature, - 63 C and + or - 143 C after each irradiation. A value of 139.5 mw/sq cm was used as AMO incident energy rate per unit area. The 10 OHM-cm cells appear more efficient than 1 OHM-cm cells after exposure to a fluence greater than 10 to the 14th power e/sq cm. The 1.0 MeV electron damage coefficients for both 1 OHM-cm and 10 OHM-cm cells are somewhat less than those for previously irradiated cells at room temperature. The values of the damage coefficients increase as the cell temperatures decrease. Efficiencies pertaining to maximum power output are about the same as those of n on p silicon cells evaluated previously.

Isotachophoresis system having larger-diameter channels flowing into channels with reduced diameter and with selectable counter-flow

Energy Technology Data Exchange (ETDEWEB)

Mariella, Jr., Raymond P.

2018-03-06

An isotachophoresis system for separating a sample containing particles into discrete packets including a flow channel, the flow channel having a large diameter section and a small diameter section; a negative electrode operably connected to the flow channel; a positive electrode operably connected to the flow channel; a leading carrier fluid in the flow channel; a trailing carrier fluid in the flow channel; and a control for separating the particles in the sample into discrete packets using the leading carrier fluid, the trailing carrier fluid, the large diameter section, and the small diameter section.

7 CFR 51.320 - Diameter.

Science.gov (United States)

2010-01-01

... Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards, Inspections, Marketing Practices), DEPARTMENT OF AGRICULTURE REGULATIONS AND STANDARDS UNDER THE AGRICULTURAL MARKETING ACT OF 1946... Standards for Grades of Apples Definitions § 51.320 Diameter. When measuring for minimum size, “diameter...

The Study of Tissue Dose Perturbation by Air Cavity with 6MV Photon Beam

International Nuclear Information System (INIS)

Shin, Byung Chul; Yoo, Myung Jin; Moon, Chang Woo; Jeung, Tae Sig; Yum, Ha Yong

1995-01-01

Purpose : To determine the perturbation effect in the tissue downstream from surface layers of lesions located in the air/tumor-tissue interface of larynx using 6MV photon beam. Materials and Methods : Thermoluminescent dosimeters(TLDs). Were embedded at 3 measurement locations in slab no.7 of a humanoid phantom and exposed to forward and backward direction using various field sizes(4 X 4cm 2 - 15 X 15 cm 2 ). Results : At the air/tissue interface, forward dose perturbation factor(FDPF) is about 1.085 with 4 X 4 cm 2 , 1.05 with 7 X 7 cm 2 , 1.048 with 10 X 10 cm 2 , and 1.041 with 15 X 15 cm 2 . Backscatter dose perturbation factor(BDPF) is about 0.99 with 4 X 4 cm 2 , 0.981 with 7 X 7 cm 2 , 0.956 with 10 X 10 cm 2 and 0.97 with 15 X 15 cm 2 . Conclusion : FDPF is greater as field size is smaller. And FDPF is smaller as the distance is further from the air/tissue interface

Effects of proton irradiation and temperature on 1 ohm-cm and 10 ohm-cm silicon solar cells

Science.gov (United States)

Nicoletta, C. A.

1973-01-01

The 1 ohm-cm and 10 ohm-cm silicon solar cells were exposed to 1.0 MeV protons at a fixed flux of 10 to the 9th power P/sq cm-sec and fluences of 10 to the 10th power, 10 to the 11th power, 10 to the 12th power and 3 X 10 to the 12th power P/sq cm. I-V curves of the cells were made at room temperature, 65 C and 165 C after each irradiation. A value of 139.5 mw/sq cm was taken as AMO incident energy rate per unit area. Degradation occurred for both uncovered 1 ohm-cm and 10 ohm-cm cells. Efficiencies are generally higher than those of comparable U.S. cells tested earlier. Damage (loss in maximum power efficiency) with proton fluence is somewhat higher for 10 ohm-cm cells, measured at the three temperatures, for fluences above 2 X 10 to the 11th power P/sq cm. Cell efficiency, as expected, changes drastically with temperature.

40 CFR 91.309 - Engine intake air temperature measurement.

Science.gov (United States)

2010-07-01

... measurement. 91.309 Section 91.309 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR... Provisions § 91.309 Engine intake air temperature measurement. (a) Engine intake air temperature measurement must be made within 100 cm of the air-intake of the engine. The measurement location must be either in...

Ultrasonic determination of interfacial area, void fraction and Sauter mean diameter in bubbly flow

International Nuclear Information System (INIS)

Bensler, Henri-Paul

1990-01-01

In this research thesis, the author shows that it is possible to determine, by means of a single measurement, the interface surface, the vacuum rate, and the Sauter mean diameter in a bubbly water-air flow. The developed technique relies on the measurement of the attenuation of an ultrasound beam by the two-phase medium, and on the use of broadband transducers associated with a multi-frequency screening method. Tests in standing water or in forced convection are performed in ducts with a square cross section with a side of 40, 80, or 120 mm. Values obtained with ultrasounds are compared with those determined by using photographs (interface surfaces, Sauter diameters) or by using a gauge pressure, or by using X rays (vacuum rate). This method based on ultrasound attenuation reveals to be simple and in good agreement with reference methods [fr

When the diameter of the abdominal aorta should be considered as abnormal? A new ultrasonographic index using the wrist circumference as a body build reference

Energy Technology Data Exchange (ETDEWEB)

Sconfienza, Luca Maria, E-mail: io@lucasconfienza.it [Servizio di Radiologia, IRCCS Policlinico San Donato, Piazza Malan 2 – 20097 San Donato Milanese, Milano (Italy); Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Piazza Malan 2 – 20097 San Donato Milanese, Milano (Italy); Santagostino, Ilaria, E-mail: isantagostino@hotmail.it [Scuola di Specializzazione in Radiodiagnostica, Università degli Studi di Milano, Via Festa del Perdono 7, 20100 Milano (Italy); Di Leo, Giovanni, E-mail: gianni.dileo77@gmail.com [Servizio di Radiologia, IRCCS Policlinico San Donato, Piazza Malan 2 – 20097 San Donato Milanese, Milano (Italy); Piazza, Raffaella; Gozzi, Gino, E-mail: radiologia.como@hsacomo.org [Diagnostica per Immagini, Ospedale Sant’Anna, Via Ravona 1, 22020 San Fermo della Battaglia, Como (Italy); Trimarchi, Santi, E-mail: satrimarchi@gmail.com [Chirurgia Vascolare II, IRCCS Policlinico San Donato, Piazza Malan 2 – 20097 San Donato Milanese, Milano (Italy); Sardanelli, Francesco, E-mail: francesco.sardanelli@unimi.it [Servizio di Radiologia, IRCCS Policlinico San Donato, Piazza Malan 2 – 20097 San Donato Milanese, Milano (Italy); Dipartimento di Scienze Biomediche per la Salute, Università degli Studi di Milano, Piazza Malan 2 – 20097 San Donato Milanese, Milano (Italy)

2013-10-01

Purpose: To use US to evaluate the normal values of aortic diameter (AD), stratifying the population by age, gender and body build, as measured using wrist circumference (WC). Materials and methods: Between April 2010 and February 2012, consecutive patients ≥ 30 years of age, without history of abdominal aortic aneurysm (AAA) were prospectively enrolled. They underwent an abdominal ultrasonography for reasons other than aorta evaluation. AD was measured at the infrarenal (AD{sub 1}), intermediate (AD{sub 2}), and iliac bifurcation (AD{sub 3}) levels: a diameter ≥ 3 cm was considered as an aneurysm. The maximal aortic diameter (AD{sub max}) was measured for AAA patients. WC was measured; AD/WC ratio was calculated and presented in percentage: the range of normal values was obtained excluding AAA cases and calculated as mean ± 1.96 × standard deviation. Pearson correlation coefficient was used. Results: We recruited 1200 patients, 15 (1.25%; age range = 64–86 years) had AAA. AD ranges of the other patients were: AD{sub 1} = 0.74–1.84 cm, AD{sub 2} = 0.78–1.85 cm, and AD{sub 3} = 0.68–1.76 cm for females; AD{sub 1} = 0.86–2.02 cm, AD{sub 2} = 0.91–2.08 cm, and AD{sub 3} = 0.84–1.95 cm for males. AD{sub 2}/WC ratio of non-AAA patients range was 4–15%, with only one outlier at 18%, while AD{sub max}/WC ratio of AAA patients range was 15–35% (p < 0.001). ADs were significantly correlated with WC (r = 0.253, p < 0.001 for AD{sub 1}, r = 0.318, p < 0.001 for AD{sub 2} and r = 0.280, p < 0.001 for AD{sub 3}). Conclusion: The definition of normal AD should consider body build. An AD{sub 2}/WC ratio of 15% may be regarded as a threshold to differentiate AAA- from non-AAA patients. Patients with AD{sub 2}/WC values comprised between 12% and 15% may be at risk for AAA.

Turbulent flow in a vessel agitated by side entering inclined blade turbine with different diameter using CFD simulation

Science.gov (United States)

Fathonah, N. N.; Nurtono, T.; Kusdianto; Winardi, S.

2018-03-01

Single phase turbulent flow in a vessel agitated by side entering inclined blade turbine has simulated using CFD. The aim of this work is to identify the hydrodynamic characteristics of a model vessel, which geometrical configuration is adopted at industrial scale. The laboratory scale model vessel is a flat bottomed cylindrical tank agitated by side entering 4-blade inclined blade turbine with impeller rotational speed N=100-400 rpm. The effect of the impeller diameter on fluid flow pattern has been investigated. The fluid flow patterns in a vessel is essentially characterized by the phenomena of macro-instabilities, i.e. the flow patterns change with large scale in space and low frequency. The intensity of fluid flow in the tank increase with the increase of impeller rotational speed from 100, 200, 300, and 400 rpm. It was accompanied by shifting the position of the core of circulation flow away from impeller discharge stream and approached the front of the tank wall. The intensity of fluid flow in the vessel increase with the increase of the impeller diameter from d=3 cm to d=4 cm.

GEJALA INTRUSI AIR LAUT DI DAERAH PESISIR PADELEGAN, PADEMAWU DAN SEKITARNYA

Directory of Open Access Journals (Sweden)

Wisnu Arya Gemilang

2016-11-01

Full Text Available Sebagian wilayah pesisir Pademawu dan sekitarnya, Pamekasan, dijumpai adanya air tanah payau hingga asin dengan pelamparan yang cukup luas. Tujuan penelitian ini adalah untuk memetakan sebaran air tanah asin hingga payau tersebut, baik pada akuifer dangkal maupun akuifer dalam dan juga untuk mengetahui penyebab keasinan air tanah tersebut. Sebaran air tanah asin dipetakan berdasarkan nilai daya hantar listrik (DHL dengan kriteria tingkat keasinan sebagaimana ditetapkan oleh Panitia Ad Hoc Intrusi Air Asin Jakarta. Sedangkan penyebab keasinan air tanah dianalisa berdasarkan fasies hidrokimia dengan diagram Trilinier Piper. Hasil penelitian menunjukkan bahwa pada akuifer dangkal air tanah agak payau hingga asin dengan nilai DHL > 15.000 µS/cm – 50.000 µS/cm dijumpai pada bagian Selatan Pademawu sepanjang pesisir pantai meliputi Padelegan, Jumiang, Tanjung, Manjungan dan Pademawu Timur. Sedangkan untuk air tanah dalam seluruhnya dalam kondisi tawar dengan nilai DHL < 1500 µS/cm, berada pada bagian Utara dari daerah penelitian meliputi kecamatan Tlanakan, Galis, Pamekasan dan  Larangan. Berdasarkan nilai DHL bahwa daerah bagian Utara penelitian tidak terdeteksi adanya proses penyusupan air laut pada air tanah.INDICATION OF SEA WATER INTRUSION IN COASTAL PADELEGAN, PADEMAWU AREAIn the part of Pademawu coastal areas, Pamekasan, was found brackish groundwater that spreading progressively. The purpose of this study was to map the distribution of salt to brackish groundwater, both in the shallow aquifer and the deep aquifer and also to find out the cause of the salinity of the ground water. Salt groundwater distribution was mapped based on the electrical conductivity (EC with a salinity level criteria as established by Panitia Ad Hoc Intrusi Air Asin Jakarta. While the causes of groundwater salinity were analyzed based on hydrochemical facies with Trilinier Piper diagram. The results showed that the shallow groundwater aquifers slightly brackish to

Cleansing technique using high-velocity steam-air micromist jet spray.

Science.gov (United States)

Fukuda, Koichi; Ishihara, Masayuki; Murakami, Kaoru; Nakamura, Shingo; Sato, Yoko; Kuwabara, Masahiro; Fujita, Masanori; Kiyosawa, Tomoharu; Yokoe, Hidetaka

2017-10-01

Application of a high-velocity steam-air micromist jet spray (HVS-AMJS; micromist average diameter: 2.4 μm) for cleansing the skin is proposed. Low-pressure steam is mixed with compressed air (pH 6.5) in a nozzle, and then sprayed at a pressure of ≦0.25 MPa and a velocity of ≧0.34 m/s on the skin or surface of material located approximately 5-10 cm from the nozzle. The temperature on the sprayed surface and water flow rate could be controlled between 42 °C and 46 °C and at approximately 50 mL/min, respectively. Compared with ultrasonic cleansing with tap water and rubbing with only tap water, the HVS-AMJS successfully removed fluorescent lotion covering pieces of wood and significantly reduced both the number of coliforms and the total viable counts on pieces of wood and gauze. Furthermore, the HVS-AMJS effectively removed oily ink from the skin of hairless rats, and temporarily elevated the skin temperature and blood flow, indicating massage effects. The striking characteristics of this cleansing technique using HVS-AMJS are not only its ability to remove microbes and residue without using any chemicals or detergents but also its massage effects.

First phase of small diameter heater experiments in tuff

International Nuclear Information System (INIS)

Zimmerman, R.M.

1983-01-01

As part of the Nevada Nuclear Waste Storage Investigations (NNWSI) project, we have undertaken small diameter heater experiments in the G-Tunnel Underground Facility on the Nevada Test Site (NTS). These experiments are to evaluate the thermal and hydrothermal behavior which might be encountered if heat producing nuclear waste were disposed of in welded and nonwelded tuffs. The two Phase I experiments discussed have focused on vertical borehole emplacements. In each experiment, temperatures were measured along the surface of the 10.2-cm-dia heater and the 12.7-cm-dia boreholes. For each experiment, measurements were compared with computer model representations. Maximum temperatures reached were: 196 0 C for the welded tuff after 21 days of operations at 800W and 173 0 C for the nonwelded tuff after 35 days of operations at 500W. Computed results indicate that the same heat transfer model (includes conduction and radiation only) can describe the behavior of both tuffs using empirical techniques to describe pore water vaporization. Hydrothermal measurements revealed heat-indiced water migration. Results indicated that small amounts of liquid water migrated into the welded tuff borehole early in the heating period. Once the rock-wall temperatures exceeded 94 0 C, in both tuffs, there was mass transport of water vapor as evidence indicated condensation cooler regions. Borehole pressures remained essentially ambient during the thermal periods

Profile Control by Biased Electrodes in Large Diameter RF Produced Pl asma

Science.gov (United States)

Shinohara, Shunjiro; Matsuoka, Norikazu; Yoshinaka, Toshiro

1998-10-01

Control of the plasma profile has been carried out, using the voltage biasing method in the large diameter (45 cm) RF (radio frequency) produced plasma in the presence of the uniform magnetic field (less than 1200 G). Under the low filling pressure condition of 0.16 mTorr, changing the biasing voltages to the three individual end plates with concentric circular ring shapes, the radial electron density (about 10^10 cm-3) profile could be changed from the hollow to the peaked one. On the contrary, the nearly flat electron temperature (several eV) profile did not change appreciably. The azimuthal rotation velocity measured by the Mach probe, i.e. directional probe, showed the different radial profiles (but nearly uniform along the axis) depending on the biasing voltage. This velocity became slower with the low magnetic field (less than 200 G) or in the higher pressure regime up to 20 mTorr with the higher electron density. The experimental results by other biasing methods will also be presented.

Numerical simulation of air- and water-flow experiments in a block of variably saturated, fractured tuff from Yucca Mountain, Nevada

International Nuclear Information System (INIS)

Kwicklis, E.M.; Healy, R.W.; Thamir, F.; Hampson, D.

1998-01-01

Numerical models of water movement through variably saturated, fractured tuff have undergone little testing against experimental data collected from relatively well-controlled and characterized experiments. This report used the results of a multistage experiment on a block of variably saturated, fractured, welded tuff and associated core samples to investigate if those results could be explained using models and concepts currently used to simulate water movement in variably saturated, fractured tuff at Yucca Mountain, Nevada, the potential location of a high-level nuclear-waste repository. Aspects of the experiment were modeled with varying degrees of success. Imbibition experiments performed on cores of various lengths and diameters were adequately described by models using independently measured permeabilities and moisture-characteristic curves, provided that permeability reductions resulting from the presence of entrapped air were considered. Entrapped gas limited maximum water saturations during imbibition to approximately 0.70 to 0,80 of the fillable porosity values determined by vacuum saturation. A numerical simulator developed for application to fluid flow problems in fracture networks was used to analyze the results of air-injection tests conducted within the tuff block through 1.25-cm-diameter boreholes. These analyses produced estimates of transmissivity for selected fractures within the block. Transmissivities of other fractures were assigned on the basis of visual similarity to one of the tested fractures. The calibrated model explained 53% of the observed pressure variance at the monitoring boreholes (with the results for six outliers omitted) and 97% of the overall pressure variance (including monitoring and injection boreholes) in the subset of air-injection tests examined

Appendiceal diameter: CT versus sonographic measurements

Energy Technology Data Exchange (ETDEWEB)

Orscheln, Emily S. [University of Cincinnati Medical Center, Department of Radiology, Cincinnati, OH (United States); Trout, Andrew T. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

2016-03-15

Ultrasound and CT are the dominant imaging modalities for assessment of suspected pediatric appendicitis, and the most commonly applied diagnostic criterion for both modalities is appendiceal diameter. The classically described cut-off diameter for the diagnosis of appendicitis is 6 mm when using either imaging modality. To demonstrate the fallacy of using the same cut-off diameter for both CT and US in the diagnosis of appendicitis. We conducted a retrospective review of patients younger than 18 years who underwent both US and CT of the appendix within 24 h. The shortest transverse dimension of the appendix was measured at the level of the proximal, mid and distal appendix on US and CT images. We compared mean absolute difference in appendiceal diameter between US and CT, using the paired t-test. We reviewed exams of 155 children (58.7% female) with a mean age of 11.3 ± 4.2 years; 38 of the children (24.5%) were diagnosed with appendicitis. The average time interval between US and CT was 7.0 ± 5.4 h. Mean appendiceal diameter measured by CT was significantly larger than that measured by US in cases without appendicitis (5.3 ± 1.0 mm vs. 4.7 ± 1.1 mm, P < 0.0001) and in cases with appendicitis (8.3 ± 2.2 mm vs. 7.0 ± 2.0 mm, P < 0.0001). Mean absolute diameter difference at any location along the appendix was 1.3-1.4 mm in normal appendices and 2 mm in cases of appendicitis. Measured appendiceal diameter differs between US and CT by 1-2 mm, calling into question use of the same diameter cut-off (6 mm) for both modalities for the diagnosis of appendicitis. (orig.)

Appendiceal diameter: CT versus sonographic measurements

International Nuclear Information System (INIS)

Orscheln, Emily S.; Trout, Andrew T.

2016-01-01

Ultrasound and CT are the dominant imaging modalities for assessment of suspected pediatric appendicitis, and the most commonly applied diagnostic criterion for both modalities is appendiceal diameter. The classically described cut-off diameter for the diagnosis of appendicitis is 6 mm when using either imaging modality. To demonstrate the fallacy of using the same cut-off diameter for both CT and US in the diagnosis of appendicitis. We conducted a retrospective review of patients younger than 18 years who underwent both US and CT of the appendix within 24 h. The shortest transverse dimension of the appendix was measured at the level of the proximal, mid and distal appendix on US and CT images. We compared mean absolute difference in appendiceal diameter between US and CT, using the paired t-test. We reviewed exams of 155 children (58.7% female) with a mean age of 11.3 ± 4.2 years; 38 of the children (24.5%) were diagnosed with appendicitis. The average time interval between US and CT was 7.0 ± 5.4 h. Mean appendiceal diameter measured by CT was significantly larger than that measured by US in cases without appendicitis (5.3 ± 1.0 mm vs. 4.7 ± 1.1 mm, P < 0.0001) and in cases with appendicitis (8.3 ± 2.2 mm vs. 7.0 ± 2.0 mm, P < 0.0001). Mean absolute diameter difference at any location along the appendix was 1.3-1.4 mm in normal appendices and 2 mm in cases of appendicitis. Measured appendiceal diameter differs between US and CT by 1-2 mm, calling into question use of the same diameter cut-off (6 mm) for both modalities for the diagnosis of appendicitis. (orig.)

Significance of air humidity and air velocity for fungal spore release into the air

Science.gov (United States)

Pasanen, A.-L.; Pasanen, P.; Jantunen, M. J.; Kalliokoski, P.

Our previous field studies have shown that the presence of molds in buildings does not necessarily mean elevated airborne spore counts. Therefore, we investigated the release of fungal spores from cultures of Aspergillus fumigatus, Penicillium sp. and Cladosporium sp. at different air velocities and air humidities. Spores of A. fumigatus and Penicillium sp. were released from conidiophores already at air velocity of 0.5 ms -1, whereas Cladosporium spores required at least a velocity of 1.0 ms -1. Airborne spore counts of A. fumigatus and Penicillium sp. were usually higher in dry than moist air, being minimal at relative humidities (r.h.) above 70%, while the effect of r.h. on the release of Cladosporium sp. was ambivalent. The geometric mean diameter of released spores increased when the r.h. exceeded a certain level which depends on fungal genus. Thus, spores of all three fungi were hygroscopic but the hygroscopicity of various spores appeared at different r.h.-ranges. This study indicates that spore release is controlled by external factors and depends on fungal genus which can be one reason for considerable variation of airborne spore counts in buildings with mold problems.

Determination of very small activities of radioiodine and plutonium in air

International Nuclear Information System (INIS)

Irlweck, K.; Karg, V.; Schoenfeld, T.; Sorantin, H.; Steger, F.

1982-01-01

A mobile high volume sampler with the following characteristics was developed: air flow rate 5000 m 3 .h - 1 , total cross section of the seven activated charcoal filter units 0.6 m 2 , diameter of each filter unit 33 cm, thickness of charcoal layer 4 - 7 cm. The sorbed radioiodine is eluted from the charcoal in a circulation unit by a circulating solution (sodium hydroxide/hydrazine) and is transfered into a sorbent containing silver (ion exchange resin with colloidal silver), thereby bringing about a reduction in volume by a factor of approximately 1000. The radioiodine activity is then determined by gamma spectrometric measurement of the silver containing sorbent. The overall radioiodine yield measured with 123 I spike (sorption on charcoal and transfer to the silver containing sorbent) is 75 (+- 7)%. A detection limit of 0.02 mBq.m - 3 is achieved for 131 I. If the sampler is operated with the standard throughput of 5000 m 3 .h - 1 , this limit applies to one hour average concentration values. Results of environmental monitorings for the period 1979 - 1982 at the Research Center Seibersdorf for 131 I (up to 2,6 mBq/m 3 ) and for plutonium (up to 4 μBq/m 3 ) are given. (Author)

The effect of the nasopharyngeal air cavity on x-ray interface doses

International Nuclear Information System (INIS)

Kan, W.K.; Wu, P.M.; Leung, H.T.; Lo, T.C.; Chung, C.W.; Kwong, D.L.W.; Sham, S.T.

1998-01-01

We investigated the impact of air cavities in head and neck cancer patients treated by photon beams based on clinical set-ups. The phantom for investigation was constructed with a cubic air cavity of 4x4x4cm 3 located at the centre of a 30x30x16cm 3 solid water slab. The cavity cube was used to resemble an extreme case for the nasal cavity. Apart from measuring the dose profiles and central axis percentage depth dose distribution, the dose values in 0.25x0.25x0.25cm 3 voxels at regions around the air cavity were obtained by Monte Carlo simulations. A mean dose value was taken over the voxels of interest at each depth for evaluation. Single-field results were added to study parallel opposed field effects. For 10x10cm 2 parallel opposed fields at 4, 6 and 8 MV, the mean dose at regions near the lateral interfaces of the cavity cube were decreased by 1 to 2% due to the lack of lateral scatter, while the mean dose near the proximal and distal interfaces was increased by 2 to 4% due to the greater transmission through air. Secondary build-up effects at points immediately beyond the air cavity cube are negligible using field sizes greater than 4x4cm 2 . For most head and neck treatment, the field sizes are usually 6x6cm 2 or greater, and most cavity volumes are smaller than our chosen dimensions. Therefore, the influence of closed air cavities on photon interface doses is not significant in clinical treatment set-ups. (author)

histological changes in the lungs of adult wistar rats following

African Journals Online (AJOL)

Exposure to paint fumes over time is dangerous to the lungs and can cause respiratory distress ... harmful chemicals such as -solvents and volatile ... the death of some factory workers where nanoparticles ... diameter 75cm X 50cm X 30cm hole was bored on the cover of .... and allergic effects in children: A review. Indoor Air ...

Building air exhaustion device

International Nuclear Information System (INIS)

Suzuki, Seijiro.

1995-01-01

An opening is formed on the side wall of a building such as of a nuclear power plant, and a blow out panel is held (supported) by a clip for closing the opening. A large-diameter pipeline is connected at one end to the opening so as to cover the blow out panel, and immersed at the other end in a pool water. When a pipeline such as of main steam pipelines is ruptured in the building, high temperature and high pressure coolants are flown out from the ruptured port, and the pressure in the building is elevated. The blow out panel falls off from the side of the building by the elevation of the pressure in the building. Steams or compressed air discharged from the opening is introduced to the pool through the large diameter pipeline, then the steams are condensed by the pool water and radioactive materials contained in the condensed steams are kept in the pool water. Radioactive materials contained in the released compression air are also removed into the pool water. (I.N.)

An experimental study on two-phase pressure drop in small diameter horizontal, downward inclined and vertical tubes

Directory of Open Access Journals (Sweden)

Autee Arun

2015-01-01

Full Text Available An experimental study of two-phase pressure drop in small diameter tubes orientated horizontally, vertically and at two other downward inclinations of θ= 300 and θ = 600 is described in this paper. Acrylic transparent tubes of internal diameters 4.0, 6.0, and 8.0 mm with lengths of 400 mm were used as the test section. Air-water mixture was used as the working fluid. Two-phase pressure drop was measured and compared with the existing correlations. These correlations are commonly used for calculation of pressure drop in macro and mini-microchannels. It is observed that the existing correlations are inadequate in predicting the two-phase pressure drop in small diameter tubes. Based on the experimental data, a new correlation has been proposed for predicting the two-phase pressure drop. This correlation is developed by modification of Chisholm parameter C by incorporating different parameters. It was found that the proposed correlation predicted two-phase pressure drop at satisfactory level.

MODELING AND DESIGN OF INNOVATIVE SMALL DIAMETER GRAVITY SEWERAGE SYSTEM

Directory of Open Access Journals (Sweden)

Tadeusz Nawrot

2017-05-01

Full Text Available The article presents modern methods of hydraulic design of an innovative small diameter gravity sewerage system. In this system, domestic wastewater is preliminary treated in septic tanks equipped with outlet filters, thus the effluent features are similar to those of clear water. Innovative non-return valves at the outlets eliminate introduction of air to the system and thus the flows can be treated as one-phase ones. Computer codes EPANET 2 and SWMM 5.0 were applied and compared. Two flow schemes typical for the sewerage system were implemented in EPANET 2, and the third - in a slightly modified SWMM 5.0. Simulation results were validated on empirical data obtained on a laboratory physical model, consisting of four tanks of minimum volumes 600 dm3 each, connecting PE pipelines of diameters 25 mm and 36 mm and relevant sanitary fittings. Water inflows, typical for domestic wastewater outflows from single homesteads, were provided by a pump. Water flows were measured using water meters with pulse outputs, and water levels in tanks by pressure transducers. Hydraulic characteristics of filters and non-return valves were provided. Simulation results showed good agreement with the empirical data. Ranges of values of design parameters, needed for successful application of both codes, were established and discussed.

[Comparative study of the effects of sterilized air and perfluoropropane gas tamponades on recovery after idiopathic full-thickness macular hole surgery].

Science.gov (United States)

He, F; Zheng, L; Dong, F T

2017-05-11

Objective: To compare the effects of sterilized air and perfluoropropane (C(3)F(8)) tamponades on recovery after vitrectomy for the treatment of idiopathic full-thickness macular hole (IFTMH). Methods: Case control study. Seventy-three eyes of 69 consecutive cases underwent vitrectomy with air (53 eyes) or 10% C(3)F(8) gas (20 eyes) tamponade. Surgical outcomes were retrospectively analyzed between the two groups, including logarithm of the minimal angle of resolution (logMAR) and optical coherence tomography findings like the size of the macular hole and the photoreceptor layer defect. Results: Preoperatively, the mean best corrected visual acuity (BCVA) was (0.10±0.49), the mean hole diameter was (777.9±320.7) μm, and the mean diameter of the photoreceptor layer defect was (1 709.3±516.0) μm in the sterilized air group, while in the C(3)F(8) group, the mean BCVA was (0.07±0.50), the mean hole diameter was (853.9±355.0) μm, and the mean defect diameter was (1 480.5±429.9) μm. The primary closure rate was 90.6% in the sterilized air group and 95.0% in the C(3)F(8) group. One month after surgery, the mean BCVA was (0.17±0.41), and the mean diameter of the photoreceptor layer defect was (820.5±598.0) μm in the sterilized air group, while in the C(3)F(8) group, the mean BCVA was 0.12±0.49, and the mean defect diameter was (762.5±658.0) μm. There was no statistically significant difference in the closure rate (χ(2)=0.019), BCVA ( t =-1.689), hole diameter ( t =0.837) and diameter of the photoreceptor layer defect ( t =0.338) between the two groups( P >0.05). Conclusions: Vitrectomy with sterilized air tamponade is safe and effective for the treatment of IFTMH and even cases with relatively large diameters. (Chin J Ophthalmol, 2017, 53: 327 - 331) .

Delayed hadrons in air showers observed in Chacaltaya

International Nuclear Information System (INIS)

Kakimoto, Fumio

1984-01-01

Bolivian Air Shower Joint Experiment group has studied high energy interaction by measuring the aspect of vertical growth of air showers of 10 16 eV or more at Mt. Chacaltaya Space Physics Observatory at 5200 m above sea level and atmospheric depth of 550 g/cm 2 . The aspect of vertical growth of electrons from about 100 g/cm 2 to about 400 g/cm 2 of atmospheric depth obtained by the measured results of the time of arrival distribution of air Cherenkov radiation at Mt. Chacaltaya agreed with the one predicted from the enhanced 1/2 power of E model. Since the vertical growth of electrons and muons in about 10 17 eV air showers from the atmospheric apex was difficult to give the unified explanation with known interaction models, the University of Tokyo group has proposed a two-component model for air shower growth. If this second component is formed from heavy particles or heavy quantum state as parents, it should be observed as the component which arrives later in air shower. Thus, the measurement and experiment on the delayed hadrons in air showers have been started. In this paper, the experiment, analysis and results are reported. It is clear that the parent particles which caused such a phenomenon were not pions which were multiply generated by the interaction generally known. Therefore, an exact simulating calculation must be performed and compared with the experimental results to obtain the final conclusion from the measured results of this time. (Wakatsuki, Y.)

Comparison of pressure between barium reduction and air reduction of the intussusception in children

Energy Technology Data Exchange (ETDEWEB)

Lee, Kyung Hwan; Park, Sang Gyu; Park, Choong Ki; Yoon, Jong Sup [Hallym University College of Medicine, Seoul (Korea, Republic of)

1989-08-15

There are many method of treatment of the intussusception in children, including surgery, barium reduction, air reduction, and saline enema under ultrasonographic monitoring. Among them, barium reduction and air reduction have been used widely as nonsurgical method of treatment in radiologic department. During barium reduction, the bottle filled with barium solution must not be elevated over a 3 feet from the operating table. In air reduction, diagnostic pressure is about 60 mmHg and pressure during reduction usually is maintained between 90 mmHg and 130 mmHg. The authors have studied about pressure difference of barium solution by changing height of the bottle filled with barium solution, and have compared with pressure in air reduction. The results are as follows; 1. Pressure of 20 w/v % barium solution at the 60 cm height is 44.4 mmHg, and 69.6 mmHg at the 90 cm height. 2. Pressure of 40 w/v % barium solution at the 60 cm height is 51.4 mmHg, and 80.1 mmHg at the 90 cm height. 3. Pressure of 40 w/v % barium solution at the 90cm height is much lower than the pressure maintained during air reduction, and this difference in pressure may be one of the causes of low reduction rate in barium reduction then air reduction. 4. The pressure gradient per 10 cm height is about 8.45 mmHg in 20 w/v % barium solution, about 9.21 mmHg in 30 w/v % barium solution, and about 9.72 mmHg 40 w/v % barium solution. 5. Intraluminal pressure difference between the barium reduction and the air reduction is probably of the major causes of rapid diagnosis and high reduction rate in the air reduction.

Comparison of pressure between barium reduction and air reduction of the intussusception in children

International Nuclear Information System (INIS)

Lee, Kyung Hwan; Park, Sang Gyu; Park, Choong Ki; Yoon, Jong Sup

1989-01-01

There are many method of treatment of the intussusception in children, including surgery, barium reduction, air reduction, and saline enema under ultrasonographic monitoring. Among them, barium reduction and air reduction have been used widely as nonsurgical method of treatment in radiologic department. During barium reduction, the bottle filled with barium solution must not be elevated over a 3 feet from the operating table. In air reduction, diagnostic pressure is about 60 mmHg and pressure during reduction usually is maintained between 90 mmHg and 130 mmHg. The authors have studied about pressure difference of barium solution by changing height of the bottle filled with barium solution, and have compared with pressure in air reduction. The results are as follows; 1. Pressure of 20 w/v % barium solution at the 60 cm height is 44.4 mmHg, and 69.6 mmHg at the 90 cm height. 2. Pressure of 40 w/v % barium solution at the 60 cm height is 51.4 mmHg, and 80.1 mmHg at the 90 cm height. 3. Pressure of 40 w/v % barium solution at the 90cm height is much lower than the pressure maintained during air reduction, and this difference in pressure may be one of the causes of low reduction rate in barium reduction then air reduction. 4. The pressure gradient per 10 cm height is about 8.45 mmHg in 20 w/v % barium solution, about 9.21 mmHg in 30 w/v % barium solution, and about 9.72 mmHg 40 w/v % barium solution. 5. Intraluminal pressure difference between the barium reduction and the air reduction is probably of the major causes of rapid diagnosis and high reduction rate in the air reduction

Height-diameter allometry and above ground biomass in tropical montane forests: Insights from the Albertine Rift in Africa.

Science.gov (United States)

Imani, Gérard; Boyemba, Faustin; Lewis, Simon; Nabahungu, Nsharwasi Léon; Calders, Kim; Zapfack, Louis; Riera, Bernard; Balegamire, Clarisse; Cuni-Sanchez, Aida

2017-01-01

Tropical montane forests provide an important natural laboratory to test ecological theory. While it is well-known that some aspects of forest structure change with altitude, little is known on the effects of altitude on above ground biomass (AGB), particularly with regard to changing height-diameter allometry. To address this we investigate (1) the effects of altitude on height-diameter allometry, (2) how different height-diameter allometric models affect above ground biomass estimates; and (3) how other forest structural, taxonomic and environmental attributes affect above ground biomass using 30 permanent sample plots (1-ha; all trees ≥ 10 cm diameter measured) established between 1250 and 2600 m asl in Kahuzi Biega National Park in eastern Democratic Republic of Congo. Forest structure and species composition differed with increasing altitude, with four forest types identified. Different height-diameter allometric models performed better with the different forest types, as trees got smaller with increasing altitude. Above ground biomass ranged from 168 to 290 Mg ha-1, but there were no significant differences in AGB between forests types, as tree size decreased but stem density increased with increasing altitude. Forest structure had greater effects on above ground biomass than forest diversity. Soil attributes (K and acidity, pH) also significantly affected above ground biomass. Results show how forest structural, taxonomic and environmental attributes affect above ground biomass in African tropical montane forests. They particularly highlight that the use of regional height-diameter models introduces significant biases in above ground biomass estimates, and that different height-diameter models might be preferred for different forest types, and these should be considered in future studies.

Investigation of air flow in open-throat wind tunnels

Science.gov (United States)

Jacobs, Eastman N

1930-01-01

Tests were conducted on the 6-inch wind tunnel of the National Advisory Committee for Aeronautics to form a part of a research on open-throat wind tunnels. The primary object of this part of the research was to study a type of air pulsation which has been encountered in open-throat tunnels, and to find the most satisfactory means of eliminating such pulsations. In order to do this it was necessary to study the effects of different variable on all of the important characteristics of the tunnel. This paper gives not only the results of the study of air pulsations and methods of eliminating them, but also the effects of changing the exit-cone diameter and flare and the effects of air leakage from the return passage. It was found that the air pulsations in the 6-inch wind tunnel could be practically eliminated by using a moderately large flare on the exit cone in conjunction with leakage introduced by cutting holes in the exit cone somewhat aft of its minimum diameter.

Size distribution of air bubbles entering the brain during cardiac surgery.

Directory of Open Access Journals (Sweden)

Emma M L Chung

Full Text Available Thousands of air bubbles enter the cerebral circulation during cardiac surgery, but whether high numbers of bubbles explain post-operative cognitive decline is currently controversial. This study estimates the size distribution of air bubbles and volume of air entering the cerebral arteries intra-operatively based on analysis of transcranial Doppler ultrasound data.Transcranial Doppler ultrasound recordings from ten patients undergoing heart surgery were analysed for the presence of embolic signals. The backscattered intensity of each embolic signal was modelled based on ultrasound scattering theory to provide an estimate of bubble diameter. The impact of showers of bubbles on cerebral blood-flow was then investigated using patient-specific Monte-Carlo simulations to model the accumulation and clearance of bubbles within a model vasculature.Analysis of Doppler ultrasound recordings revealed a minimum of 371 and maximum of 6476 bubbles entering the middle cerebral artery territories during surgery. This was estimated to correspond to a total volume of air ranging between 0.003 and 0.12 mL. Based on analysis of a total of 18667 embolic signals, the median diameter of bubbles entering the cerebral arteries was 33 μm (IQR: 18 to 69 μm. Although bubble diameters ranged from ~5 μm to 3.5 mm, the majority (85% were less than 100 μm. Numerous small bubbles detected during cardiopulmonary bypass were estimated by Monte-Carlo simulation to be benign. However, during weaning from bypass, showers containing large macro-bubbles were observed, which were estimated to transiently affect up to 2.2% of arterioles.Detailed analysis of Doppler ultrasound data can be used to provide an estimate of bubble diameter, total volume of air, and the likely impact of embolic showers on cerebral blood flow. Although bubbles are alarmingly numerous during surgery, our simulations suggest that the majority of bubbles are too small to be harmful.

Compressibility of air in fibrous materials

DEFF Research Database (Denmark)

Tarnow, Viggo

1996-01-01

The dynamic compressibility of air in fibrous materials has been computed for two assumed configurations of fibers which are close to the geometry of real fiber materials. Models with parallel cylinders placed in a regular square lattice and placed randomly are treated. For these models...... the compressibility is computed approximately from the diameter and mean distances between cylinders. This requires calculation of the air temperature, which is calculated for cylinders in a regular lattive by the Wigner-Seitz cell approximation. In the case of random placement, the calculation is done by a summation...... over thermal waves from all fibers, and by a self-consistent procedure. Figuren of the compressibility in the frequency range 10-100 000 Hz, are given for diameter of the cylinders of 6.8 µm, and mean distances between them from 50 to 110 µm, which corresponds to glass wool with a density of 40 to 16...

Corrections to air kerma rate measurements of 125I brachytherapy sources to free space conditions

International Nuclear Information System (INIS)

Shipley, D.R.; Duane, S.

1994-05-01

Air kerma rate measurements have been made between 40 cm and 100 cm from one of a set of 125 I reference sources within the facilities of Amersham International plc. Monte Carlo techniques have been used to calculate the air kerma rate components over the same range of distances from this source. After comparing the calculated data with measurements, the compliance of the data with the inverse square law was investigated, and corrections were derived to obtain the air kerma rate at 1 m in free space from each source. Simulations of the experimental setup with an isotropic monoenergetic point source close to the effective energy of 125 I were found to reproduce the air kerma rate measurements reasonably accurately, and indicated that the contribution due to scattered photons was significant. The overall correction (which is defined as the product of individual corrections for chamber size effect, air attenuation and radiation scatter) required to the inverse square law to obtain the air kerma rate at 1 m in free space was found to be 0.981, 0.984 and 0.980, respectively, for air kerma rate measurements at 40 cm, 60 cm and 100 cm from the 125 I reference source. The total uncertainty in these corrections was estimated to be 0.88% at the 1σ level. (author)

Experimental determination of kQ factors for cylindrical ionization chambers in 10 cm × 10 cm and 3 cm × 3 cm photon beams from 4 MV to 25 MV.

Science.gov (United States)

Krauss, A; Kapsch, R P

2014-08-07

For the ionometric determination of absorbed dose to water, Dw, in megavoltage photon beams from a linear accelerator, beam-quality-dependent correction factors, kQ, are used for the ionization chambers. By using a water calorimeter, these factors can be determined experimentally and with substantially lower standard uncertainties compared to calculated values of the kQ, which are published in various dosimetry protocols. In this investigation, kQ for different types of cylindrical ionization chambers (NE 2561, NE 2571, FC 65 G) were determined experimentally in 10 cm × 10 cm photon beams from 4 MV to 25 MV (corresponding beam quality index TPR20,10 from 0.64 to 0.80). The measurements were carried out at the linear accelerator facility of the Physikalisch-Technische Bundesanstalt. It is shown that the kQ factors for a single ionization chamber in 10 cm × 10 cm photon beams can be measured with a relative standard uncertainty of 0.31%. In addition to these measurements in 10 cm × 10 cm fields, kQ factors for the NE 2561 chamber were also determined in smaller 3 cm × 3 cm photon beams between 6 MV and 25 MV. In this case, relative standard uncertainties between 0.35 % and 0.38 % are achieved for the kQ factors. It is found for this ionization chamber, that the ratio of the kQ factors in 3 cm × 3 cm and in 10 cm × 10 cm beams increases with increasing TPR20,10 to reach a value of 1.0095 at TPR20,10 = 0.8 with a relative standard uncertainty of 0.4 %.

Potential for large-diameter NTD silicon production in the Advanced Test Reactor

International Nuclear Information System (INIS)

Herring, J.S.; Korenke, R.E.

1984-01-01

The Advanced Test Reactor (ATR) is a 250-MW(t) flux-trap reactor located at the Idaho National Engineering Laboratory (INEL). Within the reflector are four 124-mm-diameter I-holes, which are available for silicon irradiation. Two large irradiation volumes of 0.5 m x 0.4 m x 1.2 m and 0.5 m x 0.2 m x 1.2 m are also available for transmutation doping. Thermal fluxes in these locations range from 0.56 to 23.0 x 10 12 nt/cm 3 -s. Use of the ATR for providing neutron transmutation doping (NTD) services in sizes not available elsewhere in the United States may be feasible

Spectral Longwave Cloud Radiative Forcing as Observed by AIRS

Science.gov (United States)

Blaisdell, John M.; Susskind, Joel; Lee, Jae N.; Iredell, Lena

2016-01-01

AIRS V6 products contain the spectral contributions to Outgoing Longwave Radiation (OLR), clear-sky OLR (OLR(sub CLR)), and Longwave Cloud Radiative Forcing (LWCRF) in 16 bands from 100 cm(exp -1) to 3260 cm(exp -1). We show climatologies of selected spectrally resolved AIRS V6 products over the period of September 2002 through August 2016. Spectrally resolved LWCRF can better describe the response of the Earth system to cloud and cloud feedback processes. The spectral LWCRF enables us to estimate the fraction of each contributing factor to cloud forcing, i.e.: surface temperature, mid to upper tropospheric water vapor, and tropospheric temperature. This presentation also compares the spatial characteristics of LWCRF from AIRS, CERES_EBAF Edition-2.8, and MERRA-2. AIRS and CERES LWCRF products show good agreement. The OLR bias between AIRS and CERES is very close to that of OLR(sub CLR). This implies that both AIRS and CERES OLR products accurately account for the effect of clouds on OLR.

Determination of Am-241, Cm-242 and Cm-244 in environmental samples

International Nuclear Information System (INIS)

Afsar, M.; Schuettelkopf, H.

1988-01-01

An analytical procedure for the determination of Am and Cm in environmental, liquid and gaseous effluent samples was developed. It is based on extraction chromatography with subsequent anion and cation exchange to remove matrix elements and to purify Am and Cm, which are then electrode posited from an oxalate/HCl medium. The mean value of the chemical yield is about 90%. A detection limit of 7 μBq/g is achieved. The decontamination factors for important α emitters are > 10 4 . Four analyses/week can be performed by one technician. (orig./RB) [de

Comparison of air space measurement imaged by CT, small-animal CT, and hyperpolarized Xe MRI

Science.gov (United States)

Madani, Aniseh; White, Steven; Santyr, Giles; Cunningham, Ian

2005-04-01

Lung disease is the third leading cause of death in the western world. Lung air volume measurements are thought to be early indicators of lung disease and markers in pharmaceutical research. The purpose of this work is to develop a lung phantom for assessing and comparing the quantitative accuracy of hyperpolarized xenon 129 magnetic resonance imaging (HP 129Xe MRI), conventional computed tomography (HRCT), and highresolution small-animal CT (μCT) in measuring lung gas volumes. We developed a lung phantom consisting of solid cellulose acetate spheres (1, 2, 3, 4 and 5 mm diameter) uniformly packed in circulated air or HP 129Xe gas. Air volume is estimated based on simple thresholding algorithm. Truth is calculated from the sphere diameters and validated using μCT. While this phantom is not anthropomorphic, it enables us to directly measure air space volume and compare these imaging methods as a function of sphere diameter for the first time. HP 129Xe MRI requires partial volume analysis to distinguish regions with and without 129Xe gas and results are within %5 of truth but settling of the heavy 129Xe gas complicates this analysis. Conventional CT demonstrated partial-volume artifacts for the 1mm spheres. μCT gives the most accurate air-volume results. Conventional CT and HP 129Xe MRI give similar results although non-uniform densities of 129Xe require more sophisticated algorithms than simple thresholding. The threshold required to give the true air volume in both HRCT and μCT, varies with sphere diameters calling into question the validity of thresholding method.

Intussusception reduction: Effect of air vs. liquid enema on radiation dose

Energy Technology Data Exchange (ETDEWEB)

Kaplan, Summer L.; Edgar, J.C.; Anupindi, Sudha A.; Zhu, Xiaowei [The Children' s Hospital of Philadelphia, Department of Radiology, Philadelphia, PA (United States); University of Pennsylvania, Perelman School of Medicine, Philadelphia, PA (United States); Magill, Dennise; Felice, Marc A. [University of Pennsylvania, Environmental Health and Radiation Safety, Philadelphia, PA (United States)

2017-10-15

Both air and radiopaque liquid contrast are used to reduce ileocolic intussusception under fluoroscopy. Some suggest air lowers radiation dose due to shorter procedure times. However, air enema likely lowers radiation dose regardless of fluoroscopy time due to less density over the automatic exposure control cells. We test the hypothesis that air enema reduction of ileocolic intussusception results in lower radiation dose than liquid contrast enema independent of fluoroscopy time. We describe a role for automatic exposure control in this dose difference. We retrospectively evaluated air and liquid intussusception reductions performed on a single digital fluoroscopic unit during a 26-month period. We compared patient age, weight, gender, exam time of day and year, performing radiologist(s), radiographic image acquisitions, grid and magnification use, fluoroscopy time and dose area product. We compared categorical and continuous variables statistically using chi-square and Mann-Whitney U tests, respectively. The mean dose area product was 2.7-fold lower for air enema, 1.3 ± 0.9 dGy.cm{sup 2}, than for liquid, 3.5 ± 2.5 dGy.cm{sup 2} (P<0.005). The mean fluoroscopy time was similar between techniques. The mean dose area product/min was 2.3-fold lower for air, 0.6 ± 0.2 dGy.cm{sup 2}/min, than for liquid, 1.4 ± 0.5 dGy.cm{sup 2}/min (P<0.001). No group differences were identified in other measured dose parameters. Fluoroscopic intussusception reduction using air enema uses less than half the radiation dose of liquid contrast enema. Dose savings are independent of fluoroscopy time and are likely due to automatic exposure control interaction. (orig.)

The effect of the nasopharyngeal air cavity on x-ray interface doses

Energy Technology Data Exchange (ETDEWEB)

Kan, W.K. [Hong Kong Polytechnic University, Department of Optometry and Radiography, Hung Hom, Kowloon (Hong Kong); Hong Kong Baptist Hospital, 222 Waterloo Road, Kowloon (Hong Kong); Wu, P.M.; Leung, H.T.; Lo, T.C.; Chung, C.W.; Kwong, D.L.W.; Sham, S.T. [Queen Mary Hospital, Department of Radiotherapy (Hong Kong)

1998-03-01

We investigated the impact of air cavities in head and neck cancer patients treated by photon beams based on clinical set-ups. The phantom for investigation was constructed with a cubic air cavity of 4x4x4cm{sup 3} located at the centre of a 30x30x16cm{sup 3} solid water slab. The cavity cube was used to resemble an extreme case for the nasal cavity. Apart from measuring the dose profiles and central axis percentage depth dose distribution, the dose values in 0.25x0.25x0.25cm{sup 3} voxels at regions around the air cavity were obtained by Monte Carlo simulations. A mean dose value was taken over the voxels of interest at each depth for evaluation. Single-field results were added to study parallel opposed field effects. For 10x10cm{sup 2} parallel opposed fields at 4, 6 and 8 MV, the mean dose at regions near the lateral interfaces of the cavity cube were decreased by 1 to 2% due to the lack of lateral scatter, while the mean dose near the proximal and distal interfaces was increased by 2 to 4% due to the greater transmission through air. Secondary build-up effects at points immediately beyond the air cavity cube are negligible using field sizes greater than 4x4cm{sup 2}. For most head and neck treatment, the field sizes are usually 6x6cm{sup 2} or greater, and most cavity volumes are smaller than our chosen dimensions. Therefore, the influence of closed air cavities on photon interface doses is not significant in clinical treatment set-ups. (author)

Nineteen-Foot Diameter Explosively Driven Blast Simulator; TOPICAL

International Nuclear Information System (INIS)

VIGIL, MANUEL G.

2001-01-01

This report describes the 19-foot diameter blast tunnel at Sandia National Laboratories. The blast tunnel configuration consists of a 6 foot diameter by 200 foot long shock tube, a 6 foot diameter to 19 foot diameter conical expansion section that is 40 feet long, and a 19 foot diameter test section that is 65 feet long. Therefore, the total blast tunnel length is 305 feet. The development of this 19-foot diameter blast tunnel is presented. The small scale research test results using 4 inch by 8 inch diameter and 2 foot by 6 foot diameter shock tube facilities are included. Analytically predicted parameters are compared to experimentally measured blast tunnel parameters in this report. The blast tunnel parameters include distance, time, static, overpressure, stagnation pressure, dynamic pressure, reflected pressure, shock Mach number, flow Mach number, shock velocity, flow velocity, impulse, flow duration, etc. Shadowgraphs of the shock wave are included for the three different size blast tunnels

Beam depolarization and gain saturation in neodymium rods with a diameter of 85 mm

Energy Technology Data Exchange (ETDEWEB)

Sukhanov, V N; Ugodenko, A A

1990-04-01

Depolarization and gain saturation were investigated in rod amplifiers using phosphate and silicate Nd glasses 85 mm in diameter and 300 mm in length at a pulse duration of 35 ns. Total depolarization losses over the rod cross section were measured for various radial distributions of the small-signal gain. For the phosphate glass the losses amounted to 3-6 percent; for the silicate glass, they amounted to 4-7 percent. Saturation energy densities of 4.5 + or - 0.4 and 8.0 + or - 0.7 J/sq cm were obtained for the phosphate and silicate glass, respectively. 8 refs.

Straw Combustion in a Grate Furnace

DEFF Research Database (Denmark)

Lans, Robert Pieter Van Der

1998-01-01

Fixed-bed combustion of straw has been conducted in a 15 cm diameter and 137 cm long cylindrical reactor. Air, which could be preheated, was introduced through the bottom plate. The straw was ignited at the top with a radiation heater. After ignition, when a self-sustaining reaction front...

On the performance of air conditioner with heat pipe for cooling air in the condenser

Energy Technology Data Exchange (ETDEWEB)

Naphon, Paisarn, E-mail: paisarnn@swu.ac.t [Thermo-Fluids and Heat Transfer Enhancement Laboratory (TFHT), Department of Mechanical Engineering, Faculty of Engineering, Srinakharinwirot University, 63 Rangsit-Nakhornnayok Rd., Ongkharak, Nakhorn-Nayok 26120 (Thailand)

2010-11-15

Improvement of the air conditioning system performance by using the heat pipe for cooling air before entering the condenser is presented. In the experiment, the heat pipe is fabricated from the straight copper tube with the diameter and length of 10, 600 mm, respectively. The arrangements of the heat pipe sets are arranged in the staggered layout with the tube rows of 1, 2, 3. R134a refrigerant is used as working fluid in the heat pipe set for this present study. By comparing with a conventional air conditioning system, the air conditioning system with three rows of heat pipe gives the highest COP and EER with increasing of 6.4%, 17.5%, respectively. On the global warming and environment problems, the results of this study are expected to lead to guidelines that will allow the improved performance of the air conditioning systems which reduce its energy consumption.

On the performance of air conditioner with heat pipe for cooling air in the condenser

International Nuclear Information System (INIS)

Naphon, Paisarn

2010-01-01

Improvement of the air conditioning system performance by using the heat pipe for cooling air before entering the condenser is presented. In the experiment, the heat pipe is fabricated from the straight copper tube with the diameter and length of 10, 600 mm, respectively. The arrangements of the heat pipe sets are arranged in the staggered layout with the tube rows of 1, 2, 3. R134a refrigerant is used as working fluid in the heat pipe set for this present study. By comparing with a conventional air conditioning system, the air conditioning system with three rows of heat pipe gives the highest COP and EER with increasing of 6.4%, 17.5%, respectively. On the global warming and environment problems, the results of this study are expected to lead to guidelines that will allow the improved performance of the air conditioning systems which reduce its energy consumption.

Operation of Small Radio Telescope (SRT) recorded 21 cm spectral line of Hydrogen at VATLY Laboratory

International Nuclear Information System (INIS)

Pham Ngoc Dong; Pham Tuan Anh; Pham Ngoc Diep; Pham Thi Tuyet Nhung; Nguyen Van Hiep

2013-01-01

A small radio telescope (SRT) has been installed on the roof of the Hanoi astrophysics laboratory VATLY. It is equipped with a 2.6 m diameter mobile parabolic dish remotely controlled in elevation and azimuth and with super-heterodyne detection around the 21 cm hydrogen line. They demonstrate the high quality of the telescope performance and are used to evaluate lobe size, signal to noise ratios, anthropogenic interferences and measurement accuracies. Particular attention is given to the measurement of the pointing accuracy. First results of observations of the Sun and of the centre of the Milky Way are presented. (author)

All-solid-state Al-air batteries with polymer alkaline gel electrolyte

Science.gov (United States)

Zhang, Zhao; Zuo, Chuncheng; Liu, Zihui; Yu, Ying; Zuo, Yuxin; Song, Yu

2014-04-01

Aluminum-air (Al-air) battery is one of the most promising candidates for next-generation energy storage systems because of its high capacity and energy density, and abundance. The polyacrylic acid (PAA)-based alkaline gel electrolyte is used in all-solid-state Al-air batteries instead of aqueous electrolytes to prevent leakage. The optimal gel electrolyte exhibits an ionic conductivity of 460 mS cm-1, which is close to that of aqueous electrolytes. The Al-air battery peak capacity and energy density considering only Al can reach 1166 mAh g-1-Al and 1230 mWh g-1-Al, respectively, during constant current discharge. The battery prototype also exhibits a high power density of 91.13 mW cm-2. For the battery is a laminated structure, area densities of 29.2 mAh cm-2 and 30.8 mWh cm-2 are presented to appraise the performance of the whole cell. A novel design to inhibit anodic corrosion is proposed by separating the Al anode from the gel electrolyte when not in use, thereby effectively maintaining the available capacity of the battery.

Comparison of dose measurements in water versus in air for therapy

International Nuclear Information System (INIS)

Nasukha

1987-01-01

Comparison of dose measurements in water versus in air for therapy. Dose measurements in water and in the air had been done by teletherapy unit Co-60 Picker Model V 4m/60 with Farmer dosimeter. The result of inverse square law, TAR, PDD, and PSF compared to BJR No. 17 produced a difference of more than 4,65% with SSD 80 cm. Doses in water calculated from the result of dose measurement in air using BJR tables given, was compared with direct dose measurement in water. Values of 0,9850 to 1,0302 were obtained if using inverse square law, PDD and PSF formula. Using inverse square law and TAR, values of 0,9474 to 1,0197 were obtained for 4 depths and 5 field sizes. Measurements done in 5 cm depth and 10 cm x 10 cm field size using both methods, were still good. (author). 7 figs, 8 refs

Fast separation of enantiomers by capillary electrophoresis using a combination of two capillaries with different internal diameters.

Science.gov (United States)

Šebestová, Andrea; Petr, Jan

2017-12-01

The combination of capillaries with different internal diameters was used to accelerate the separation of enantiomers in capillary electrophoresis. Separation of R,S-1,1'-binaphthalene-2,2'-diyl hydrogen phosphate using isopropyl derivative of cyclofructan 6 was studied as a model system. The best separation conditions included 500 mM sodium borate pH 9.5 with 60 mM concentration of the chiral selector. Separation lasted approx. 1.5 min using the combination of 50 and 100 μm id capillaries of 9.7 cm and 22.9 cm, respectively. It allowed approx. 12-fold acceleration in comparison to the traditional long-end separation mainly due to the higher electroosmotic flow generated in the connected capillaries. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Numerical modeling of aerosol particles scavenging by drops as a process of air depollution

OpenAIRE

Cherrier , Gaël

2017-01-01

This PhD-Thesis is dedicated to the numerical modeling of aerosol particles scavenging by drops. Investigated situations are about aerosol particles of aerodynamic diameter ranging from 1 nm to 100 µm captured in the air by water drops of diameter varying between 80 µm and 600 µm, with corresponding droplet Reynolds number ranging between 1 and 100. This air depollution modeling is achieved in two steps. The first step consists in obtaining a scavenging kernel predicting the flow rate of aero...

Propagação do marmeleiro 'Japonês' por estaquia e alporquia realizadas em diferentes épocas Propagation of 'Japonês' quince for cutting and air layering technique in different periods

Directory of Open Access Journals (Sweden)

Rafael Pio

2007-04-01

Full Text Available O presente trabalho teve como objetivo avaliar diferentes épocas de realização da estaquia e alporquia em plantas do marmeleiro 'Japonês' (Chaenomelis sinensis L.. Foram coletadas estacas lenhosas de 25 cm de comprimento, sem folhas e diâmetro de 0,8 cm. Uma parte das estacas foi estratificada a frio por 30 dias (estacas embrulhadas em jornal umedecido e protegidas com saco plástico à temperatura de 4ºC e outra parte colocada diretamente para enraizar em leito de areia umedecido, em telado constituído por sombrite 50% de luminosidade. As coletas das estacas foram efetuadas nos meses de abril, maio, junho e julho. Foram realizados alporques (mergulhia aérea nas mesmas plantas do marmeleiro em iguais períodos, realizando-se anéis de 2 cm de largura, envolvidos com esfagno umedecido, cobertos e amarrados nas extremidades com plástico transparente. Após 90 dias do estaqueamento e da alporquia, coletaram-se os seguintes dados biométricos: porcentagem de estacas vivas, enraizadas, calejadas, brotadas e número médio de raízes por estaca; porcentagem de alporques vivos, enraizados, calejados e número médio de raízes por alporque. Concluiu-se que estacas coletadas em junho sem estratificação e alporques realizados em julho promoveram melhores resultados.The objective of present work was to verify the different periods of accomplishment of the cutting and air layering in 'Japonês' quince (Chaenomelis sinensis L.. Woody cutting with 25 cm of length, without leaves and diameter of 0.8 cm was collected. A part of the cutting was submitted to cold stratificated for 30 days (cuttings in humidified newspaper and protected with plastic sack in 4ºC of temperature and other part placed directly to rooting, in nursery conditions with 50% of brightness. The collections of cutting were made in the months of April, May, June and July. Air layering was accomplished (air layering in the same plants of quince in the same periods, taking place

Diameter 2 properties and convexity

Czech Academy of Sciences Publication Activity Database

Abrahamsen, T. A.; Hájek, Petr Pavel; Nygaard, O.; Talponen, J.; Troyanski, S.

2016-01-01

Roč. 232, č. 3 (2016), s. 227-242 ISSN 0039-3223 R&D Projects: GA ČR GA16-07378S Institutional support: RVO:67985840 Keywords : diameter 2 property * midpoint locally uniformly rotund * Daugavet property Subject RIV: BA - General Mathematics Impact factor: 0.535, year: 2016 https://www.impan.pl/pl/wydawnictwa/czasopisma-i-serie-wydawnicze/studia- mathematica /all/232/3/91534/diameter-2-properties-and-convexity

Diameter characterization of timber species in primary forests of Cerro Murrucucu

International Nuclear Information System (INIS)

Villa G, Ana Maria

2006-01-01

This study in Cerro Murrucucu forests establishes the minimum fell diameter (DMC) and its fell cycle (C). It classifies the forest in 1 (Iess damaged) and 2 (severely damaged). Ten species were selected by means of the importance Value Index (IVI) and the DMC was determined. C was estimated through the times of step method. Pentaclethra macroloba showed the highest IVI (21.5% and 21.09% for forests 1 and 2, respectively). In spite of the deterioration of forest 2 the species still showed highest importance. In forest 1 an equilibrium can be deduced, whereas in forest 2 most of the considered species show instability. The DMC for forests 1 and 2 were 30 and 20 cm respectively, indicating extractive activities are deteriorating the latest. C was 51.8 years

Ambient air pollution and years of life lost in Ningbo, China

Science.gov (United States)

He, Tianfeng; Yang, Zuyao; Liu, Tao; Shen, Yueping; Fu, Xiaohong; Qian, Xujun; Zhang, Yuelun; Wang, Yong; Xu, Zhiwei; Zhu, Shankuan; Mao, Chen; Xu, Guozhang; Tang, Jinling

2016-03-01

To evaluate the burden of air pollution on years of life lost (YLL) in addition to mortality, we conducted a time series analysis based on the data on air pollution, meteorological conditions and 163,704 non-accidental deaths of Ningbo, China, 2009-2013. The mean concentrations of particulate matter with aerodynamic diameter population for both outcomes. These findings clarify the burden of air pollution on YLL and highlight the importance and urgency of air pollution control in China.

Novel device (AirWave) to assess endotracheal tube migration: a pilot study.

Science.gov (United States)

Nacheli, Gustavo Cumbo; Sharma, Manish; Wang, Xiaofeng; Gupta, Amit; Guzman, Jorge A; Tonelli, Adriano R

2013-08-01

Little is known about endotracheal tube (ETT) migration during routine care among critically ill patients. AirWave is a novel device that uses sonar waves to measure ETT migration and obstructions in real time. The aim of the present study is to assess the accuracy of the AirWave to evaluate ETT migration. In addition, we determined the degree of variation in ETT position and tested whether more pronounced migration occurs in specific clinical scenarios. After institutional review board approval, we included mechanically ventilated patients from February 2012 to May 2012. A chest radiography (CXR) was obtained at baseline and 24 hours when clinically indicated. The ETT distance at the lips was recorded at baseline and every 4 hours. The AirWave system continuously recorded ETT position changes from baseline, and luminal obstructions. A total of 42 patients (age: 61 [SD ±13] years, men: 52%) were recruited. A total of 19 patients had measurements of ETT migration at 24 hours by the 3 methodologies used in this study. The mean (SD) of the ETT migration at 24 hours was +0.04 (1.2), -0.42 (0.7) and +0.34 (1.81) cm when measured by portable CXR, ETT distance at the teeth and AirWave device, respectively. Bland-Altman analysis of tube migration at 24 hours comparing the AirWave with CXR readings showed a bias of 0.1 cm with 95% limit of agreement of -3.8 and +4.3 cm. Comparison of tube migration at 24 hours determined by AirWave with ETT distance at the lips revealed a bias of -0.4 with 95% limit of agreement -3.7 to +3 cm, similar to the values observed between CXR and ETT distance at the lips (bias of -0.3 cm, 95% limit of agreement of -3.4 to +2.8 cm). Factors associated with ETT migration at 24 hours were ETT size and initial measurement from ETT tip to carina by portable CXR. AirWave detected in eight patients some degree of ETT obstruction (30% ± 9.6%) that resolved with prompt ETT catheter suction. The AirWave may provide useful information regarding ETT

Displacer Diameter Effect in Displacer Pulse Tube Refrigerator

Science.gov (United States)

Zhu, Shaowei

2017-12-01

Gas driving displacer pulse tube refrigerators are one of the work recovery type of pulse tube refrigerators whose theoretical efficiency is the same as Stirling refrigerators'. Its cooling power is from the displacement of the displacer. Displace diameter, rod diameter and pressure drop of the regenerator influence the displacement, which are investigated by numerical simulation. It is shown that the displacement ratio of the displacer over the piston is almost not affected by the displacer diameter at the same rod diameter ratio, or displacer with different diameters almost has the same performance.

CM : becoming a technology firm

NARCIS (Netherlands)

Burg, van J.C.; Reymen, I.M.M.J.; Dolmans, S.A.M.

2011-01-01

Founded in 2000 as a Short Message Service (SMS) marketing company for discos (clubs), CM evolved into a technology provider for SMS services. By 2008, CM was market leader in The Netherlands, a position won by offering high quality services at low prices. In 2010, the founders of the company were

Experimental verification of air flow rate measurement for representative isokinetic air sampling in ventilation stacks

International Nuclear Information System (INIS)

Okruhlica, P.; Mrtvy, M.; Kopecky, Z.

2009-01-01

Nuclear facilities are obliged to monitor their discharge's influence on environment. Main monitored factions in NPP's ventilation stacks are usually noble gasses, particulates and iodine. These factions are monitored in air sampled from ventilation stack by means of sampling rosette and bypass followed with on-line measuring monitors and balance sampling devices with laboratory evaluations. Correct air flow rate measurement and representative iso-kinetic air sampling system is essential for physical correct and metrological accurate evaluation of discharge influence on environment. Pairs of measuring sensors (Anemometer, pressure gauge, thermometer and humidity meter) are symmetrically placed in horizontal projection of stack on positions based on measured air flow velocity distribution characteristic, Analogically diameter of sampling rosette nozzles and their placement in the middle of 6 - 7 annuluses are calculated for assurance of representative iso-kinetic sampling. (authors)

Experimental verification of air flow rate measurement for representative isokinetic air sampling in ventilation stacks

International Nuclear Information System (INIS)

Okruhlica, P.; Mrtvy, M.; Kopecky, Z.

2008-01-01

Nuclear facilities are obliged to monitor their discharge's influence on environment. Main monitored factions in NPP's ventilation stacks are usually noble gasses, particulates and iodine. These factions are monitored in air sampled from ventilation stack by means of sampling rosette and bypass followed with on-line measuring monitors and balance sampling devices with laboratory evaluations. Correct air flow rate measurement and representative iso-kinetic air sampling system is essential for physical correct and metrological accurate evaluation of discharge influence on environment. Pairs of measuring sensors (Anemometer, pressure gauge, thermometer and humidity meter) are symmetrically placed in horizontal projection of stack on positions based on measured air flow velocity distribution characteristic, Analogically diameter of sampling rosette nozzles and their placement in the middle of 6- 7 annuluses are calculated for assurance of representative iso-kinetic sampling. (authors)

Planar array stack design aided by rapid prototyping in development of air-breathing PEMFC

Science.gov (United States)

Chen, Chen-Yu; Lai, Wei-Hsiang; Weng, Biing-Jyh; Chuang, Huey-Jan; Hsieh, Ching-Yuan; Kung, Chien-Chih

The polymer electrolyte membrane fuel cell (PEMFC) is one of the most important research topics in the new and clean energy area. The middle or high power PEMFCs can be applied to the transportation or the distributed power system. But for the small power application, it is needed to match the power requirement of the product generally. On the other hand, the direct methanol fuel cell (DMFC) is one of the most common type that researchers are interested in, but recently the miniature or the micro-PEMFCs attract more attention due to their advantages of high open circuit voltage and high power density. The objective of this study is to develop a new air-breathing planar array fuel cell stacked from 10 cells made by rapid prototyping technology which has potential for fast commercial design, low cost manufacturing, and even without converters/inverters for the system. In this paper, the main material of flow field plates is acrylonitrile-butadiene-styrene (ABS) which allows the fuel cell be mass-manufactured by plastic injection molding technology. The rapid prototyping technology is applied to construct the prototype and verify the practicability of the proposed stack design. A 10-cell air-breathing miniature PEMFC stack with a volume of 6 cm × 6 cm × 0.9 cm is developed and tested. Its segmented membrane electrode assembly (MEA) is designed with the active surface area of 1.3 cm × 1.3 cm in each individual MEA. The platinum loading at anode and cathode are 0.2 mg cm -2 and 0.4 mg cm -2, respectively. Results show that the peak power densities of the parallel connected and serial connected stack are 99 mW cm -2 at 0.425 V and 92 mW cm -2 at 4.25 V, respectively under the conditions of 70 °C relative saturated humidity (i.e., dew point temperature), ambient temperature and free convection air. Besides, the stack performance is increased under forced convection. If the cell surface air is blown by an electric fan, the peak power densities of parallel connected and

Air pollutant penetration through airflow leaks into buildings

Energy Technology Data Exchange (ETDEWEB)

Liu, De-Ling [Univ. of California, Berkeley, CA (United States)

2002-01-01

The penetration of ambient air pollutants into the indoor environment is of concern owing to several factors: (1) epidemiological studies have shown a strong association between ambient fine particulate pollution and elevated risk of human mortality; (2) people spend most of their time in indoor environments; and (3) most information about air pollutant concentration is only available from ambient routine monitoring networks. A good understanding of ambient air pollutant transport from source to receptor requires knowledge about pollutant penetration across building envelopes. Therefore, it is essential to gain insight into particle penetration in infiltrating air and the factors that affect it in order to assess human exposure more accurately, and to further prevent adverse human health effects from ambient particulate pollution. In this dissertation, the understanding of air pollutant infiltration across leaks in the building envelope was advanced by performing modeling predictions as well as experimental investigations. The modeling analyses quantified the extent of airborne particle and reactive gas (e.g., ozone) penetration through building cracks and wall cavities using engineering analysis that incorporates existing information on building leakage characteristics, knowledge of pollutant transport processes, as well as pollutant-surface interactions. Particle penetration is primarily governed by particle diameter and by the smallest dimension of the building cracks. Particles of 0.1-1 μm are predicted to have the highest penetration efficiency, nearly unity for crack heights of 0.25 mm or higher, assuming a pressure differential of 4 Pa or greater and a flow path length of 3 cm or less. Supermicron and ultrafine particles (less than 0.1 μm) are readily deposited on crack surfaces by means of gravitational settling and Brownian diffusion, respectively. The fraction of ozone penetration through building leaks could vary widely, depending significantly on its

An experimental study of the exergetic performance of an underground air tunnel system for greenhouse cooling

International Nuclear Information System (INIS)

Ozgener, Leyla; Ozgener, Onder

2010-01-01

The present study highlights the exergetic performance characteristics of an underground air tunnel for greenhouse cooling with a 47 m horizontal, 56 cm nominal diameter U-bend buried galvanized ground heat exchanger. This system was designed and installed in the Solar Energy Institute, Ege University, Izmir, Turkey. Underground air tunnel systems, also known as earth-to-air heat exchangers, are recognized to be outstanding heating, cooling and air heating systems. On the other hand, they have not been used yet in the Turkish market. Greenhouses also have important economical potential in Turkey's agricultural sector. Greenhouses should be cooled during the summer or hot days. In order to establish optimum growth conditions in greenhouses, renewable energy sources should be utilized as much as possible. It is expected that effective use of underground air tunnels with a suitable technology in the modern greenhouses will play a leading role in Turkey in the foreseeable future. The exergy transports between the components and the destructions in each of the components of the system are determined for the average measured parameters obtained from the experimental results. Exergetic efficiencies of the system components are determined in an attempt to assess their individual performances and the potential for improvements is also presented. The daily maximum cooling coefficient of performances (COP) values for the system are also obtained to be 15.8. The total average COP in the experimental period is found to be 10.09. The system COP was calculated based on the amount of cooling produced by the air tunnel and the amount of power required to move the air through the tunnel, while the exergetic efficiency of the air tunnel is found to be in a range among 57.8-63.2%. The overall exergy efficiency value for the system on a product/fuel basis is found to be 60.7%. (author)

Gas-chromatographic quantitative determination of argon in air samples, by elimination of oxigen

International Nuclear Information System (INIS)

Sofronie, E.

1982-08-01

A method of gas-chromatographic quantitative determination of argon in air samples, by elimination of oxygen, is presented. Experiments were carried out in a static system. Conditions for the application of the method in dynamic systems are specified. Sensibility of the method: 5 10 -4 cm 3 Ar per cm 3 of air. (author)

Bifunctional electrode performance for zinc-air flow cells with pulse charging

International Nuclear Information System (INIS)

Pichler, Birgit; Weinberger, Stephan; Reščec, Lucas; Grimmer, Ilena; Gebetsroither, Florian; Bitschnau, Brigitte; Hacker, Viktor

2017-01-01

Highlights: •Manufacture of bi-catalyzed bifunctional air electrodes via scalable process. •Direct synthesis of NiCo 2 O 4 on carbon nanofibers or nickel powder support. •450 charge and discharge cycles over 1000 h at 50 mA cm −2 demonstrated. •Pulse charging with 150 mA cm −2 is successfully applied on air electrodes. •Charge and discharge ΔV of <0.8 V at 50 mA cm −2 when supplied with O 2. -- Abstract: Bifunctional air electrodes with tuned composition consisting of two precious metal-free oxide catalysts are manufactured for application in rechargeable zinc-air flow batteries and electrochemically tested via long-term pulse charge and discharge cycling experiments at 50 mA cm −2 (mean). NiCo 2 O 4 spinel, synthesized via direct impregnation on carbon nanofibers or nickel powder and characterized by energy dispersive X-ray spectroscopy and X-ray diffraction experiments, shows high activity toward oxygen evolution reaction with low charge potentials of < 2.0 V vs. Zn/Zn 2+ . La 0.6 Sr 0.4 Co 0.2 Fe 0.8 O 3 perovskite exhibits bifunctional activity and outperforms the NiCo 2 O 4 spinel in long-term stability tenfold. By combining the catalysts in one bi-catalyzed bifunctional air electrode, stable performances of more than 1000 h and 450 cycles are achieved when supplied with oxygen and over 650 h and 300 cycles when supplied with synthetic air. In addition, the pulse charging method, which is beneficial for compact zinc deposition, is successfully tested on air electrodes during long-term operation. The oxygen evolution potentials during pulse, i.e. at tripled charge current density of 150 mA cm −2 , are only 0.06–0.08 V higher compared to constant charging current densities. Scanning electron microscopy confirms that mechanical degradation caused by bubble formation during oxygen evolution results in slowly decreasing discharge potentials.

Oxygen reduction reaction catalysts of manganese oxide decorated by silver nanoparticles for aluminum-air batteries

International Nuclear Information System (INIS)

Sun, Shanshan; Miao, He; Xue, Yejian; Wang, Qin; Li, Shihua; Liu, Zhaoping

2016-01-01

In this paper, the hybrid catalysts of manganese oxide decorated by silver nanoparticles (Ag-MnO x ) are fully investigated and show the excellent oxygen reduction reaction (ORR) activity. The Ag-MnO 2 is synthesized by a facile strategy of the electroless plating of silver on the manganese oxide. The catalysts are characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Then, the ORR activities of the catalysts are systematically investigated by the rotating disk electrode (RDE) and aluminum-air battery technologies. The Ag nanoparticles with the diameters at about 10 nm are anchored on the surface of α-MnO 2 and a strong interaction between Ag and MnO 2 components in the hybrid catalyst are confirmed. The electrochemical tests show that the activity and stability of the 50%Ag-MnO 2 composite catalyst (the mass ratio of Ag/MnO 2 is 1:1) toward ORR are greatly enhanced comparing with single Ag or MnO 2 catalyst. Moreover, the peak power density of the aluminum-air battery with 50%Ag-MnO 2 can reach 204 mW cm −2 .

Evaluation of the effect of media velocity on filter efficiency and most penetrating particle size of nuclear grade high-efficiency particulate air filters.

Science.gov (United States)

Alderman, Steven L; Parsons, Michael S; Hogancamp, Kristina U; Waggoner, Charles A

2008-11-01

High-efficiency particulate air (HEPA) filters are widely used to control particulate matter emissions from processes that involve management or treatment of radioactive materials. Section FC of the American Society of Mechanical Engineers AG-1 Code on Nuclear Air and Gas Treatment currently restricts media velocity to a maximum of 2.5 cm/sec in any application where this standard is invoked. There is some desire to eliminate or increase this media velocity limit. A concern is that increasing media velocity will result in higher emissions of ultrafine particles; thus, it is unlikely that higher media velocities will be allowed without data to demonstrate the effect of media velocity on removal of ultrafine particles. In this study, the performance of nuclear grade HEPA filters, with respect to filter efficiency and most penetrating particle size, was evaluated as a function of media velocity. Deep-pleat nuclear grade HEPA filters (31 cm x 31 cm x 29 cm) were evaluated at media velocities ranging from 2.0 to 4.5 cm/sec using a potassium chloride aerosol challenge having a particle size distribution centered near the HEPA filter most penetrating particle size. Filters were challenged under two distinct mass loading rate regimes through the use of or exclusion of a 3 microm aerodynamic diameter cut point cyclone. Filter efficiency and most penetrating particle size measurements were made throughout the duration of filter testing. Filter efficiency measured at the onset of aerosol challenge was noted to decrease with increasing media velocity, with values ranging from 99.999 to 99.977%. The filter most penetrating particle size recorded at the onset of testing was noted to decrease slightly as media velocity was increased and was typically in the range of 110-130 nm. Although additional testing is needed, these findings indicate that filters operating at media velocities up to 4.5 cm/sec will meet or exceed current filter efficiency requirements. Additionally

Single and double long pulse laser ablation of aluminum induced in air and water ambient

International Nuclear Information System (INIS)

Akbari Jafarabadi, Marzieh; Mahdieh, Mohammad Hossein

2017-01-01

Highlights: • Laser ablation of aluminum target by single and double pulse (∼ 5 ns delay) in ambient air and distilled water • Comparing with air, in ambient water, plasma confinement results in higher crater depth. • In comparison with single pulse laser ablation, the absorption of the laser pulse energy is higher for double pulse regime. • As a result of ablated material expansion, the crater depth is decreased if the target is placed at lower depth. - Abstract: In this paper, single pulse and double pulse laser ablation of an aluminum target in two interaction ambient was investigated experimentally. The interaction was performed by nanosecond Nd:YAG laser beam in air and four depths (i.e. 9, 13, 17, and 21 mm) of distilled water ambient. The irradiation was carried out in single and collinear double pulse configurations in both air and liquid ambient. Crater geometry (depth and diameter) was measured by an optical microscope. The results indicated that the crater geometry strongly depends on both single pulse and double pulse configurations and interaction ambient. In single pulse regime, the crater diameter is higher for all water depths compared to that of air. However, the crater depth, depend on water depth, is higher or lower than the crater depth in air. In double pulse laser ablation, there are greater values for both crater diameters and crater depths in the water.

Project W420 Air Sampler Probe Placement Qualification Tests for Four 6-Inch Diameter Stacks: 296-A-25, 296-B-28, 296-S-22, and 296-T-18

International Nuclear Information System (INIS)

Maughan, A.D.; Glissmeyer, J.A.

1998-01-01

The W420 project covers the upgrading of effluent monitoring systems at six ventilation exhaust stacks in tank-farm facilities at the U.S. Department of Energy's Hanford Site. The discharge stacks of five of the six systems will be completely replaced. Four of these (296-A-25, 296-B-28, 296-S-22, and 296-T-18) will be of the same size, 6-inches in diameter and about 12-ft high. This report documents tests that were conducted to verify that these four stacks meet the applicable regulatory criteria regarding the placement of the air sampling probe. These criteria ensure that the contaminants in the stack are well mixed with the airflow at the location of the probe such that the extracted sample represents the whole. There are also criteria addressing the transport of the sample to the collection device. These are not covered in this report, but will need to be addressed later. These tests were conducted by Pacific Northwest National Laboratory on a full-scale model of the 6-inch stick. The sequence of tests addresses the acceptability of the flow angle relative to the probe and the uniformity of air velocity and gaseous and particle tracers in the cross section of the stack. All tests were successful, and all acceptance criteria were met

The Fogging Method with Variable of Nozle Diameter as the Mitigation Alternative for Spreading the Dust of Cement

Science.gov (United States)

Purwanta, J.; Marnoto, T.; Setyono, P.; Ramelan, A. H.

2018-03-01

The cement plant impacts on the lives of people around the factory site, one of them on the air quality, especially dust. Cement plant has made various efforts to mitigate dust generated, but the reality on the ground is still a lot of dust flying around either of the cement factory chimneys and transportation. The purpose of this study was to find the optimum condition of nozle diameter from the cement dust catcher, for mitigation the dust spread to around the cement plant. This study uses research methods such as collecting secondary data which includes data intensity rainfall, the average long rains, wind speed and direction as well as data quality monitoring dust around PT. Semen Gresik (Persero) Tbk. Tuban plant. To determine the wind direction propensity models, use a soft Windrose file. To determine the impact on the spread of dust into the environment using secondary data monitoring air quality. Results of the study is that the mitigation of dust around the cement plant is influenced by natural factors, namely the tendency of wind direction, rainfall and rainy days, and the rate of dust emission from the chimney. I try for operate the cement dust catcher with variable of nozle diameter. Finally, I find the optimum condition of nozle diameter for cement dust catcher is 1.40 mm, with line equation is y = 149.09.e 1.6237.x and error 5%. In that condition, nozle can make the fog with a good quality and it can catch the cement dust well.

Free-air ionization intensity in the lower atmosphere due to cosmic-ray

International Nuclear Information System (INIS)

Urabe, Itsumasa; Katsurayama, Kousuke

1979-01-01

Being able to be determined by subtracting the gamma-ray ionization intensity from that obtained with ionization chamber, cosmic-ray ionization intensity in free air was estimated by using with 15l air-filled ionization chamber and 3''diameter spherical NaI(Tl) scintillation spectrometer. Optimum applied voltage to 15l air-filled ionization chamber was determined in accordance with Scott and Greening's formula to obtain the ionization intensity caused by gamma-rays and cosmic-rays. Pulse-height distribution of cosmic-rays created in 3''diameter spherical NaI(Tl) scintillation spectrometer was investigated for the precise determination of gamma-ray ionization intensity. Field measurements were carried out by using with these two instruments at about 1.5 meter above the ground in the several locations around Research Reactor Institute of Kyoto University. Cosmic-ray ionization intensity in free air was estimated from the results obtained with air-filled ionization chamber and was 3.33 +- 0.15 μR/hr equivalent in natural environment near Research Reactor Institute of Kyoto University. (author)

Comparison of Colour Duplex Ultrasound with Computed Tomography to Measure the Maximum Abdominal Aortic Aneurysmal Diameter

Directory of Open Access Journals (Sweden)

C. Gray

2014-01-01

Full Text Available Introduction. Maximum diameter of an abdominal aortic aneurysm (AAA is the main indication for surgery. This study compared colour duplex ultrasound (CDU and computed tomography (CT in assessing AAA diameter. Patients and Methods. Patients were included if they had both scans performed within 90 days. Pearson’s correlation coefficient, paired t-test, and limits of agreement (LOA were calculated for the whole group. Subgroup analysis of small (6.5 cm aneurysms was performed. A P value of <0.05 was considered statistically significant. Results. 389 patients were included, giving 130 pairs of tests for comparison. Excellent correlation was in the whole group (r = 0.95 and in the subgroups (r = 0.94; 0.69; 0.96, resp.. Small LOA between the two imaging modalities was found in all subgroups. Conclusion. Small aneurysms can be accurately measured using CDU. CDU is preferable for small AAAs, but cannot supplant CT for planning aortic intervention.

Regional climate projection based on RCP scenarios in the CORDEX East Asia Domain Using RegCM4

Science.gov (United States)

Suh, M. S.; Oh, S. G.; Cha, D. H.; Kang, H. S.

2012-04-01

Regional climate projection data is essential to the adaptation and risk management for the expected climate change. In this stduy, we reproduced regional climate over CORDEX East Asia for 72 years from 1979 to 2050 with 50-km resolution using the latest regional climate model version 4, RegCM4, driven by HadGEM2-AO with about 135-km resolution under Intergovernmental Panel on Climate Change (IPCC) Representative Concentration Pathway (RCP) 8.5/4.5. Simulation skills of RegCM4 for the present climate (1980-2005, spin up time: 1979) over CORDEX East Asia are evaluated with CRU-TS (Climate Research Unit Time-Series) 3.0 and GPCP (Global Precipitation Climatology Project). And KMA ground observation data are also used for the detailed assessment of RegCM4 over South Korea. The evaluation results showed that RegCM4 reasonalbly simulated the spatial distribution, and inter-annual and seasonal variations of surface air temperature. However, it showed a non-negligible systemartic biases in the precipitation. In particular, the rainband accompanied by the seasonal march of East Asian summer monsoon was simulated too southward, below 30° N comparing to the GPCP. As a reulst, summer precipitation over South Korea and Japan island was significantly underestimated. Under RCP8.5 (RCP4.5) scenario, annual mean temperature over the CORDEX East Asia is expected to increase by + 1.6 oC(+1.4oC) above the present level (1980-2005) by the end of the future simulation period. Most of the regions (South-Korea, South-China, North-China, India, Japan, Mongolia) show the increaseing trend of surface air temperature. On the other hand, the future changes of precipitation are not systemaic at the most of regions and seasons. More detailed results including projected regional climate change will be discussed in the presentation.

Experience in the fabrication of 224 cm diameter electromagnet and coil for the Variable Energy Cyclotron Centre (Paper No. 005)

International Nuclear Information System (INIS)

Chaudhuri, J.; Das, S.K.; Bhattacharjee, B.B.

1987-02-01

The largest and vital component of a cyclotron is the D.C. magnet. The magnet core of cyclotron of the Variable Energy Cyclotron, Calcutta, is of H-shaped and made from low carbon steel casting and weighs nearly 262 tonnes. In length, width and height, the magnet is 6096mm x 2235mm x 2896mm respectively. The pole piece diameter is 2235mm with pole gap of 190.5±0.127. For convenient of handling and transportation, the upper and lower yoke of the magnet is in five pieces each. Apart from this, magnet has two numbers of legs and two numbers of pole pieces. The pole pieces are again splitted in two pieces for the convenience of fabrication assembly. The dimensions of the castings in the finished machined condition are 6096±1.5 x 889 x 447±0.026 for yoke slabs and 1117.6±0.8 (H) x 1092±1.5 (L) x 2235±1.5 (Max.) x 1422 (Min.) mm for the magnet legs. The weight of each casting of yoke slab is 19000 kg and that of leg casting is 17420 Kg each. The castings are required to have required magnetic saturation value and soundness of casting to the rolled steel standard. (author). 7 figs

Desain Pembangkit Listrik Tenaga Mikrohidro di Air Terjun Kedung Kayang

Directory of Open Access Journals (Sweden)

Dedi Nugroho

2017-12-01

Full Text Available Kedung Kayang waterfall is located on the border of  Magelang and Boyolali regency of Central Java.  The waterfall is 38 meters high, so it has the potential to be used as a micro hydro power plant (MHP. In designing the MHP, it requires some studies including hydrology, civil, mechanical, and electrical. The purpose of this research is to predict the water discharge, determine the potential of hydro power, selection of MHP sites, design of hydro turbine and electric generator. This research uses Penman Modification method to calculate evapotranspiration, Mock method to calculate water discharge, geographical mapping for MHP sites selection and cross-flow turbine design calculation. This paper presents the results of MHP design consist of MHP capacity, selection of MHP sites, penstock design, cross-flow turbine design and electric generator selection.   The  result showed that  dependable water discharge is 0.143 m3 / sec, effective head is 19.5 meters, hydro potential is 27.33 kW, and electric power that can be produced is 18 kW, length and diameter penstock are 81,74 m and 26,77 m, hydro turbine used cross flow type with outer diameter of the runner is 17,17 cm,  inner diameter is 11,45 cm and width is 59,16 cm. MHP site is located in Klakah village,  Selo Sub-district, Boyolali District.

Accuracy of free energies of hydration using CM1 and CM3 atomic charges.

Science.gov (United States)

Udier-Blagović, Marina; Morales De Tirado, Patricia; Pearlman, Shoshannah A; Jorgensen, William L

2004-08-01

Absolute free energies of hydration (DeltaGhyd) have been computed for 25 diverse organic molecules using partial atomic charges derived from AM1 and PM3 wave functions via the CM1 and CM3 procedures of Cramer, Truhlar, and coworkers. Comparisons are made with results using charges fit to the electrostatic potential surface (EPS) from ab initio 6-31G* wave functions and from the OPLS-AA force field. OPLS Lennard-Jones parameters for the organic molecules were used together with the TIP4P water model in Monte Carlo simulations with free energy perturbation theory. Absolute free energies of hydration were computed for OPLS united-atom and all-atom methane by annihilating the solutes in water and in the gas phase, and absolute DeltaGhyd values for all other molecules were computed via transformation to one of these references. Optimal charge scaling factors were determined by minimizing the unsigned average error between experimental and calculated hydration free energies. The PM3-based charge models do not lead to lower average errors than obtained with the EPS charges for the subset of 13 molecules in the original study. However, improvement is obtained by scaling the CM1A partial charges by 1.14 and the CM3A charges by 1.15, which leads to average errors of 1.0 and 1.1 kcal/mol for the full set of 25 molecules. The scaled CM1A charges also yield the best results for the hydration of amides including the E/Z free-energy difference for N-methylacetamide in water. Copyright 2004 Wiley Periodicals, Inc.

Compatible above-ground biomass equations and carbon stock estimation for small diameter Turkish pine (Pinus brutia Ten.).

Science.gov (United States)

Sakici, Oytun Emre; Kucuk, Omer; Ashraf, Muhammad Irfan

2018-04-15

Small trees and saplings are important for forest management, carbon stock estimation, ecological modeling, and fire management planning. Turkish pine (Pinus brutia Ten.) is a common coniferous species and comprises 25.1% of total forest area of Turkey. Turkish pine is also important due to its flammable fuel characteristics. In this study, compatible above-ground biomass equations were developed to predict needle, branch, stem wood, and above-ground total biomass, and carbon stock assessment was also described for Turkish pine which is smaller than 8 cm diameter at breast height or shorter than breast height. Compatible biomass equations are useful for biomass prediction of small diameter individuals of Turkish pine. These equations will also be helpful in determining fire behavior characteristics and calculating their carbon stock. Overall, present study will be useful for developing ecological models, forest management plans, silvicultural plans, and fire management plans.

Diameter effect on critical heat flux

International Nuclear Information System (INIS)

Tanase, A.; Cheng, S.C.; Groeneveld, D.C.; Shan, J.Q.

2009-01-01

The critical heat flux look-up table (CHF LUT) is widely used to predict CHF for various applications, including design and safety analysis of nuclear reactors. Using the CHF LUT for round tubes having inside diameters different from the reference 8 mm involves conversion of CHF to 8 mm. Different authors [Becker, K.M., 1965. An Analytical and Experimental Study of Burnout Conditions in Vertical Round Ducts, Aktiebolaget Atomenergie Report AE 177, Sweden; Boltenko, E.A., et al., 1989. Effect of tube diameter on CHF at various two phase flow regimes, Report IPE-1989; Biasi, L., Clerici, G.C., Garriba, S., Sala, R., Tozzi, A., 1967. Studies on Burnout, Part 3, Energia Nucleare, vol. 14, pp. 530-536; Groeneveld, D.C., Cheng, S.C., Doan, T., 1986. AECL-UO critical heat flux look-up table. Heat Transfer Eng., 7, 46-62; Groeneveld et al., 1996; Hall, D.D., Mudawar, I., 2000. Critical heat flux for water flow in tubes - II subcooled CHF correlations. Int. J. Heat Mass Transfer, 43, 2605-2640; Wong, W.C., 1996. Effect of tube diameter on critical heat flux, MaSC dissertation, Ottawa Carleton Institute for Mechanical and Aeronautical Engineering, University of Ottawa] have proposed several types of correlations or factors to describe the diameter effect on CHF. The present work describes the derivation of new diameter correction factor and compares it with several existing prediction methods

Optimization of solid state fermentation of sugar cane by Aspergillus niger considering particles size effect

Energy Technology Data Exchange (ETDEWEB)

Echevarria, J.; Rodriguez, L.J.A.; Delgado, G. (Instituto Cubano de Investigaciones de los Derivados de la Cana de Azucar (ICIDCA), La Habana (Cuba)); Espinosa, M.E. (Centro Nacional de Investigaciones Cientificas, La Habana (Cuba))

1991-01-01

The protein enrichment of sugar cane by solid state fermentation employing Aspergillus niger was optimized in a packed bed column using a two Factor Central Composit Design {alpha} = 2, considering as independent factors the particle diameter corresponding to different times of grinding for a sample and the air flow rate. It was significative for the air flow rate (optimum 4.34 VKgM) and the particle diameter (optimum 0.136 cm). The average particle size distribution, shape factor, specific surface, volume-surface mean diameter, number of particles, real and apparent density and holloweness for the different times of grinding were determined, in order to characterize the samples. (orig.).

Abnormal splenic artery diameter/hepatic artery diameter ratio in cirrhosis-induced portal hypertension

Science.gov (United States)

Zeng, Dao-Bing; Dai, Chuan-Zhou; Lu, Shi-Chun; He, Ning; Wang, Wei; Li, Hong-Jun

2013-01-01

AIM: To determine an optimal cutoff value for abnormal splenic artery diameter/proper hepatic artery diameter (S/P) ratio in cirrhosis-induced portal hypertension. METHODS: Patients with cirrhosis and portal hypertension (n = 770) and healthy volunteers (n = 31) underwent volumetric computed tomography three-dimensional vascular reconstruction to measure the internal diameters of the splenic artery and proper hepatic artery to calculate the S/P ratio. The cutoff value for abnormal S/P ratio was determined using receiver operating characteristic curve analysis, and the prevalence of abnormal S/P ratio and associations between abnormal S/P ratio and major complications of portal hypertension were studied using logistic regression. RESULTS: The receiver operating characteristic analysis showed that the cutoff points for abnormal splenic artery internal diameter and S/P ratio were > 5.19 mm and > 1.40, respectively. The sensitivity, specificity, positive predictive value, and negative predictive value were 74.2%, 45.2%, 97.1%, and 6.6%, respectively. The prevalence of an abnormal S/P ratio in the patients with cirrhosis and portal hypertension was 83.4%. Patients with a higher S/P ratio had a lower risk of developing ascites [odds ratio (OR) = 0.708, 95%CI: 0.508-0.986, P = 0.041] and a higher risk of developing esophageal and gastric varices (OR = 1.483, 95%CI: 1.010-2.175, P = 0.044) and forming collateral circulation (OR = 1.518, 95%CI: 1.033-2.230, P = 0.034). After splenectomy, the portal venous pressure and maximum and mean portal venous flow velocities were reduced, while the flow rate and maximum and minimum flow velocities of the hepatic artery were increased (P portal hypertension, and it can be used as an important marker of splanchnic hemodynamic disturbances. PMID:23483462

New host record of avian tuberculosis in an American white pelican, Pelecanus erythrorhynchos

Science.gov (United States)

Nol, P.; Brannian, R.E.; Berlowski, B.M.; Wolcott, M.J.; Rocke, T.E.

2003-01-01

An American white pelican (P. erythrorhyncos) was captured in August 1999 in California, USA. The bird was unable to fly away or evade the boat, and showed considerable aggression when captured. Numerous multifocal, 1 mm diameter, yellow masses were observed throughout the lungs and air sacs. The liver was yellow. A 6 cm diameter, firm spherical mass was present in the abdominal cavity, distal to the liver. Aspergillus spp. were cultured from the air sac tissue. Mycobacterium avium was identified from the splenic mass.

Database and prediction model for CANDU pressure tube diameter

Energy Technology Data Exchange (ETDEWEB)

Jung, J.Y.; Park, J.H. [Korea Atomic Energy Research Inst., Daejeon (Korea, Republic of)

2014-07-01

The pressure tube (PT) diameter is basic data in evaluating the CCP (critical channel power) of a CANDU reactor. Since the CCP affects the operational margin directly, an accurate prediction of the PT diameter is important to assess the operational margin. However, the PT diameter increases by creep owing to the effects of irradiation by neutron flux, stress, and reactor operating temperatures during the plant service period. Thus, it has been necessary to collect the measured data of the PT diameter and establish a database (DB) and develop a prediction model of PT diameter. Accordingly, in this study, a DB for the measured PT diameter data was established and a neural network (NN) based diameter prediction model was developed. The established DB included not only the measured diameter data but also operating conditions such as the temperature, pressure, flux, and effective full power date. The currently developed NN based diameter prediction model considers only extrinsic variables such as the operating conditions, and will be enhanced to consider the effect of intrinsic variables such as the micro-structure of the PT material. (author)

Calorimetric determination of kQ factors for NE 2561 and NE 2571 ionization chambers in 5 cm x 5 cm and 10 cm x 10 cm radiotherapy beams of 8 MV and 16 MV photons.

Science.gov (United States)

Krauss, Achim; Kapsch, Ralf-Peter

2007-10-21

The relative uncertainty of the ionometric determination of the absorbed dose to water, D(w), in the reference dosimetry of high-energy photon beams is in the order of 1.5% and is dominated by the uncertainty of the calculated chamber- and energy-dependent correction factors k(Q). In the present investigation, k(Q) values were determined experimentally in 5 cm x 5 cm and 10 cm x 10 cm radiotherapy beams of 8 MV and 16 MV bremsstrahlung by means of a water calorimeter operated at 4 degrees C. Ionization chambers of the types NE 2561 and NE 2571 were calibrated directly in the water phantom of the calorimeter. The measurements were carried out at the linear accelerator of the Physikalisch-Technische Bundesanstalt. It is shown that the k(Q) factor of a single ionization chamber can be measured with a standard uncertainty of less than 0.3%. No significant variations of k(Q) were found for the different lateral sizes of the radiation fields used in this investigation.

Effects of air temperature and velocity on the drying kinetics and product particle size of starch from arrowroot (Maranta arundinacae)

Science.gov (United States)

Caparanga, Alvin R.; Reyes, Rachael Anne L.; Rivas, Reiner L.; De Vera, Flordeliza C.; Retnasamy, Vithyacharan; Aris, Hasnizah

2017-11-01

This study utilized the 3k factorial design with k as the two varying factors namely, temperature and air velocity. The effects of temperature and air velocity on the drying rate curves and on the average particle diameter of the arrowroot starch were investigated. Extracted arrowroot starch samples were dried based on the designed parameters until constant weight was obtained. The resulting initial moisture content of the arrowroot starch was 49.4%. Higher temperatures correspond to higher drying rates and faster drying time while air velocity effects were approximately negligible or had little effect. Drying rate is a function of temperature and time. The constant rate period was not observed for the drying rate of arrowroot starch. The drying curves were fitted against five mathematical models: Lewis, Page, Henderson and Pabis, Logarithmic and Midili. The Midili Model was the best fit for the experimental data since it yielded the highest R2 and the lowest RSME values for all runs. Scanning electron microscopy (SEM) was used for qualitative analysis and for determination of average particle diameter of the starch granules. The starch granules average particle diameter had a range of 12.06 - 24.60 μm. The use of ANOVA proved that particle diameters for each run varied significantly with each other. And, the Taguchi Design proved that high temperatures yield lower average particle diameter, while high air velocities yield higher average particle diameter.

Performance of PEM Liquid-Feed Direct Methanol-Air Fuel Cells

Science.gov (United States)

Narayanan, S. R.

1995-01-01

A direct methanol-air fuel cell operating at near atmospheric pressure, low-flow rate air, and at temperatures close to 60oC would tremendously enlarge the scope of potential applications. While earlier studies have reported performance with oxygen, the present study focuses on characterizing the performance of a PEM liquid feed direct methanol-air cell consisting of components developed in house. These cells employ Pt-Ru catalyst in the anode, Pt at the cathode and Nafion 117 as the PEM. The effect of pressure, flow rate of air and temperature on cell performance has been studied. With air, the performance level is as high as 0.437 V at 300 mA/cm2 (90oC, 20 psig, and excess air flow) has been attained. Even more significant is the performance level at 60oC, 1 atm and low flow rates of air (3-5 times stoichiometric), which is 0.4 V at 150 mA/cm2. Individual electrode potentials for the methanol and air electrode have been separated and analyzed. Fuel crossover rates and the impact of fuel crossover on the performance of the air electrode have also been measured. The study identifies issues specific to the methanol-air fuel cell and provides a basis for improvement strategies.

Characterization of Conventional and High-Translucency Y-TZP Dental Ceramics Submitted to Air Abrasion.

Science.gov (United States)

Tostes, Bhenya Ottoni; Guimarães, Renato Bastos; Noronha-Filho, Jaime Dutra; Botelho, Glauco Dos Santos; Guimarães, José Guilherme Antunes; Silva, Eduardo Moreira da

2017-01-01

This study evaluated the effect of air-abrasion on t®m phase transformation, roughness, topography and the elemental composition of three Y-TZP (Yttria-stabilized tetragonal zirconia polycrystal) dental ceramics: two conventional (Lava Frame and IPS ZirCad) and one with high-translucency (Lava Plus). Plates obtained from sintered blocks of each ceramic were divided into four groups: AS (as-sintered); 30 (air-abrasion with 30 mm Si-coated Al2O3 particles); 50 (air-abrasion with 50 mm Al2O3 particles) and 150 (air-abrasion with 150 mm Al2O3 particles). After the treatments, the plates were submitted to X-ray diffractometry; 3-D profilometry and SEM/EDS. The AS surfaces were composed of Zr and t phases. All treatments produced t®m phase transformation in the ceramics. The diameter of air-abrasion particles influenced the roughness (150>50>30>AS) and the topography. SEM analysis showed that the three treatments produced groove-shaped microretentions on the ceramic surfaces, which increased with the diameter of air-abrasion particles. EDS showed a decrease in Zr content along with the emergence of O and Al elements after air-abrasion. Presence of Si was also detected on the plates air-abraded with 30 mm Si-coated Al2O3 particles. It was concluded that irrespective of the type and diameter of the particles, air-abrasion produced t®m phase transformation, increased the roughness and changed the elemental composition of the three Y-TZP dental ceramics. Lava Plus also behaved similarly to the conventional Y-TZP ceramics, indicating that this high translucency ceramic could be more suitable to build monolithic ceramic restorations in the aesthetic restorative dentistry field.

A Study of Performance Output of a Multivane Air Engine Applying Optimal Injection and Vane Angles

Directory of Open Access Journals (Sweden)

Bharat Raj Singh

2012-01-01

Full Text Available This paper presents a new concept of the air engine using compressed air as the potential power source for motorbikes, in place of an internal combustion engine. The motorbike is proposed to be equipped with an air engine, which transforms the energy of the compressed air into mechanical motion energy. A mathematical model is presented here, and performance evaluation is carried out on an air-powered novel air turbine engine. The maximum power output is obtained as 3.977 kW (5.50 HP at the different rotor to casing diameter ratios, optimal injection angle 60°, vane angle 45° for linear expansion (i.e., at minimum air consumption when the casing diameter is kept 100 mm, at injection pressure 6 bar (90 psi and speed of rotation 2500 rpm. A prototype air engine is built and tested in the laboratory. The experimental results are also seen much closer to the analytical values, and the performance efficiencies are recorded around 70% to 95% at the speed of rotation 2500–3000 rpm.

Scalability of pre-packed preparative chromatography columns with different diameters and lengths taking into account extra column effects.

Science.gov (United States)

Schweiger, Susanne; Jungbauer, Alois

2018-02-16

Small pre-packed columns are commonly used to estimate the optimum run parameters for pilot and production scale. The question arises if the experiments obtained with these columns are scalable, because there are substantial changes in extra column volume when going from a very small scale to a benchtop column. In this study we demonstrate the scalability of pre-packed disposable and non-disposable columns of volumes in the range of 0.2-20 ml packed with various media using superficial velocities in the range of 30-500 cm/h. We found that the relative contribution of extra column band broadening to total band broadening was not only high for columns with small diameters, but also for columns with a larger volume due to their wider diameter. The extra column band broadening can be more than 50% for columns with volumes larger than 10 ml. An increase in column diameter leads to high additional extra column band broadening in the filter, frits, and adapters of the columns. We found a linear relationship between intra column band broadening and column length, which increased stepwise with increases in column diameter. This effect was also corroborated by CFD simulation. The intra column band broadening was the same for columns packed with different media. An empirical engineering equation and the data gained from the extra column effects allowed us to predict the intra, extra, and total column band broadening just from column length, diameter, and flow rate. Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.

How Will Air Quality Change in South Asia by 2050?

Science.gov (United States)

Kumar, Rajesh; Barth, Mary C.; Pfister, G. G.; Delle Monache, L.; Lamarque, J. F.; Archer-Nicholls, S.; Tilmes, S.; Ghude, S. D.; Wiedinmyer, C.; Naja, M.; Walters, S.

2018-02-01

Exposure to unhealthy air causes millions of premature deaths and damages crops sufficient to feed a large portion of the South Asian population every year. However, little is known about how future air quality in South Asia will respond to changing human activities. Here we examine the combined effect of changes in climate and air pollutant emissions projected by the Representative Concentration Pathways (RCP) 8.5 and RCP6.0 on air quality of South Asia in 2050 using a state-of-the-science Nested Regional Climate model with Chemistry (NRCM-Chem). RCP8.5 and RCP6.0 are selected to represent scenarios of highest and lowest air pollution in South Asia by 2050. NRCM-Chem shows the ability to capture observed key features of variability in meteorological parameters, ozone and related gases, and aerosols. NRCM-Chem results show that surface ozone and particulate matter of less than 2.5 μm in diameter will increase significantly by midcentury in South Asia under the RCP8.5 but remain similar to present day under RCP6.0. No RCP suggest an improvement in air pollution in South Asia by midcentury. Under RCP8.5, the frequency of air pollution events is predicted to increase by 20-120 days per year in 2050 compared to the present-day conditions, with particulate matter of less than 2.5 μm in diameter predicted to breach the World Health Organization ambient air quality guidelines on an almost daily basis in many parts of South Asia. These results indicate that while the RCP scenarios project a global improvement in air quality, they generally result in degrading air quality in South Asia.

Evaluation of an air spinning process to produce tailored biosynthetic nanofibre scaffolds

International Nuclear Information System (INIS)

Sabbatier, Gad

2014-01-01

We optimised the working parameters of an innovative air spinning device to produce nanofibrous polymer scaffolds for tissue engineering applications. Scanning electron microscopy was performed on the fibre scaffolds which were then used to identify various scaffold morphologies based on the ratio of surface occupied by the polymer fibres on that covered by the entire polymer scaffold assembly. Scaffolds were then produced with the spinning experimental parameters, resulting in 90% of fibres in the overall polymer construct, and were subsequently used to perform a multiple linear regression analysis to highlight the relationship between nanofibre diameter and the air spinning parameters. Polymer solution concentration was deemed as the most significant parameter to control fibre diameter during the spinning process, despite interactions between experimental parameters. Based on these findings, viscosity measurements were performed to clarify the effect of the polymer solution property on scaffold morphology. - Highlights: • An air spinning device for nanofibre scaffold production was optimised. • Relationships between fibre diameter and spinning parameters were established. • Polymer solution concentration was the most significant parameter. • Interactions between experimental parameters also influence the spinning process. • Nanofibres were formed due to polymer chain entanglements

Outer casing of the AA antiproton production target

CERN Multimedia

CERN PhotoLab

1979-01-01

The first version of the antiproton production target was a tungsten rod, 11 cm long (actually a row of 11 rods, each 1 cm long) and 3 mm in diameter. The rod was embedded in graphite, pressure-seated into an outer casing made of stainless steel. The casing had fins for forced-air cooling.

Packing configuration performance for small stem diameters

International Nuclear Information System (INIS)

Aikin, J.A.; Spence, C.G.; Cumming, D.

1997-01-01

The extensive use of graphite packing and its excellent track record for large isolating valves in CANDU, Primary Heat Transfer (PHT) systems has resulted in an increased application of graphite packing on the conventional side. Many of these applications are in air operated valves (AOVs) where the packing sets are used on small stem diameters (<1 inch) with frequent short-cycling strokes (± 10% of full stroke). The direct application of the proven packing configurations for large isolated valves to control valve application has generated problems such as stiction, packing wear and, in isolated cases, stem stall. To address this issue, a test program was conducted at AECL, CRL by MED branch. The testing showed that by reconfiguring the packing sets and using PTFE wafers reductions in stem friction of 50% at ambient conditions, a 3 fold at hot conditions are achievable. The test program also demonstrated benefits gained in packing wear with different stem roughness finishes and the potential need to exercise small stems valves that see less than full stroke cycling. The paper describes the tests results and provides field support experience. (author)

Primary chemotherapy and preoperative-dose irradiation for patients with stage II larger than 3 CM or locally advanced non inflammatory breast cancer

International Nuclear Information System (INIS)

Touboul, E.; Lefranc, J.P.; Blondon, J.; Deniaud, E.; Buffat, L.; Benmiloud, M.; Laugier, A.; Schlienger, M.

1995-01-01

Purpose: The aims of this prospective study were to evaluate the outcome and the possibility of breast conserving treatment for patients with stage II larger than 3 cm or locally advanced non inflammatory breast cancer, after primary chemotherapy followed by external preoperative-dose irradiation. Materials and methods: Between April 1982 and June 1990, 147 consecutive patients with large breast cancer (stage II > 3 cm [n=50], stage IIIA [n=58], stage IIIB [n=35] and stage IV with isolated clinical supraclavicular or sub-clavicular node involvement [n=4] were treated. The median age was 49 years. Mean tumor size was 6 cm (range 1 - 16 cm). Sixty percent (n=88) of the patients were postmenopausal. Histological classification was : 120 infiltrating ductal carcinomas, 21 infiltrating lobular carcinomas, 4 medullary carcinomas and 2 mucosecreting carcinomas. Grade distribution according to Scarff, Bloom and Richardson was : 14 grade 1, 72 grade 2, 30 grade 3 and 31 non classified. Median follow-up was 94 months from the beginning of the treatment. The induction treatment consisted of 4 courses of chemotherapy (doxorubicin, vincristine, cyclophosphamide, 5-fluorouracil) every 4 weeks followed by preoperative irradiation (45 Gy to the breast and nodal areas) using 60Co in 141 patients and 6 MV photons in 6 patients. A fifth course of chemotherapy was given after radiation therapy and three different locoregional approaches were proposed depending on the tumoral response. In 52 patients (35%) with residual tumor larger than 3 cm in diameter or located behind the nipple or with bifocal tumors, mastectomy and axillary dissection were performed. Ninety-five other patients (65%) benefited from conservative treatment : 48 patients (33%) achieved complete remission and received a booster dose of 25 to 30 Gy to the initial tumor bed by external photon beam or by iridium 192 implant ; 47 patients (32%) who had a residual mass less than or equal to 3 cm in diameter were treated by

Induced radioactivity in air and water at medical accelerators

International Nuclear Information System (INIS)

Masumoto, K.; Takahashi, K.; Nakamura, H.; Toyoda, A.; Iijima, K.; Kosako, K.; Oishi, K.; Nobuhara, F.

2013-01-01

Activation of air and water has been evaluated at the 10 and 15 MeV linear electron accelerator facilities. At 15 MeV irradiation, the activity of 10-min-half-life 13 N was observed in the case of the air in the glove box. Air and water samples were also bombarded by 250 MeV protons and 400 MeV/u carbon, and the irradiation dose was 10 Gy at the isocenter. Upon the ion-chamber monitoring of the air sampled from the glove box, 15 O, 13 N, and 11 C activities were mainly observed. At the end of proton and carbon irradiation, the activity of the water was found to be about 10 kBq·cm -3 and several kBq·cm -3 , respectively. From the decay analysis of the induced activity in water, 15 O, 13 N, and 11 C were detected. (author)

Resonance in a Cone-Topped Tube

Directory of Open Access Journals (Sweden)

Angus Cheng-Huan Chia

2011-06-01

Full Text Available The relationship between ratio of the upper opening diameter of a cone-topped cylinder to the cylinder diameter,and the ratio of the length of the air column to resonant period was examined. Plastic cones with upper openings ranging from 1.3 cm to 3.6 cm and tuning forks with frequencies ranging from 261.6 Hz to 523.3 Hz were used. The transition from a standing wave in a cylindrical column to a Helmholtz-type resonance in a resonant cavity with a narrow opening was observed.

Relative dose efficiencies of antiscatter grids and air gaps in pediatric radiography

International Nuclear Information System (INIS)

McDaniel, D.L.; Cohen, G.; Wagner, L.K.; Robinson, L.H.

1984-01-01

The relative dose efficiencies (RDE) of various antiscatter grids and air gaps were determined for conditions simulating those found in pediatric radiography, using phantoms representing a newborn child, a 5-yr-old and a 10-yr-old child. Our data indicate than an air gap is best for the newborn, due to the low levels of scatter. The 8:1 fiber grid or 15.2-cm air gap without a grid can improve dose efficiency (DE) for the 5-yr-old child by 20%--25% relative to the 3.3-cm air gap and no-grid technique, while for the 10-yr-old child, DE can be improved by 40% with an 8:1 fiber grid

Organic matter evolution throughout a 100-cm ombrotrophic profile from an Italian floating mire

Science.gov (United States)

Zaccone, Claudio; D'Orazio, Valeria; Lobianco, Daniela; Miano, Teodoro M.

2015-04-01

The curious sight of an island floating and moving on a lake naturally, already described by Pliny the Elder in his Naturalis historia (AD 77-79), fascinated people from time immemorial. Floating mires are defined by the occurrence of emergent vegetation rooted in highly organic buoyant mats that rise and fall with changes in water level. Peat-forming floating mires could provide an exceptional tool for environmental studies, since much of their evolution, as well as the changes of the surrounding areas, is recorded in their peat deposits. A complete, 4-m deep peat core was collected in July 2012 from the floating island of Posta Fibreno, a relic mire in the Central Italy. This floating island has a diameter of ca. 30 m, a submerged thickness of about 3 m, and the vegetation is organized in concentric belts, from the Carex paniculata palisade to the Sphagnum centre. Here, some of the southernmost Italian populations of Sphagnum palustre occur. The 14C age dating of macrofossils removed from the sample at 360 cm of depth revealed that the island probably formed more than 500 yrs ago (435±20 yr BP). In the present work, we show preliminary results regarding the evolution of the organic matter along the first, ombrotrophic 100 cm of depth, hoping also to provide some insight into the possible mechanism of the evolution of this floating island. The 100 cm monolith was collected using a Wardenaar corer and cut frozen in 1-cm layers. It consists almost exclusively of Sphagnum mosses, often spaced out, in the top 20-30 cm, by leaves of Populus tremula that annually fell off. This section shows a very low bulk density, ranging from 0.017 and 0.059 g cm-3 (avg. value, 0.03±0.01 g cm-3), an average water content of 96.1±1.1%, and a gravimetric water content ranging between 14.3 and 41.5 gwater gdrypeat-1. The pH of porewaters was in the range 5-5.5. The C content along the profile ranged between 35 and 47% (avg., 41±1%), whereas the N between 0.3 and 0.9% (avg., 0.6±0

Air pollution and respiratory illness

Energy Technology Data Exchange (ETDEWEB)

Indra, G. [DIET, Uttamasolapuram, Salem (India)

2005-07-01

This presentation provides an overview of air pollution and impacts on public health. It provides a definition of pollution according to the Oxford English dictionary and categorizes the different types of pollution according to air, water, land and noise. It discusses air pollution and its pollutants (gaseous and particulate pollutants) as well as the diameter of the pollutant (dust, smoke, and gas). The paper also illustrates the formation of acid rain and discusses the amount of pollutants in the atmosphere per year. It presents occupational diseases, discusses radio active pollutants, respiratory illnesses as well as pollution prevention and control. The paper concluded that more research is needed to obtain information on ways to reduce the quantity of pollutants being discharged from special processes. 3 refs., 2 figs., 2 tabs.

Indoor air quality investigation at air-conditioned and non-air-conditioned markets in Hong Kong

International Nuclear Information System (INIS)

Guo, H.; Lee, S.C.; Chan, L.Y.

2004-01-01

To characterize indoor air quality at the markets in Hong Kong, three non-air-conditioned and two air-conditioned markets were selected for this study. The indoor air pollutants measured included PM 10 (particulate matters with aerodynamic diameter less than 10 μm), total bacteria count (TBC), carbon monoxide (CO), nitric oxide (NO), nitrogen dioxide (NO 2 ) and sulfur dioxide (SO 2 ). The indoor and outdoor concentrations of these target air pollutants at these markets were measured and compared. The effects of air conditioning, temperature/relative humidity variation and different stalls on the indoor air quality were also investigated. The results indicated that all of the average indoor concentrations of PM 10 , TBC, CO and NO 2 at the markets were below the Hong Kong Indoor Air Quality Objectives (HKIAQO) standards with a few exceptions for PM 10 and TBC. The elevated PM 10 concentrations at Hung Hom, Ngau Tau Kok and Wan Chai markets were probably due to the air filtration of outdoor airborne particulates emitted from vehicular exhaust, whereas high concentrations of airborne bacteria at Sai Ying Pun and Tin Shing markets were linked to the use of air conditioning. Correlation analysis demonstrated that indoor bacteria concentrations were correlated with temperature and relative humidity. The operation of air conditioning did not significantly reduce the levels of air pollutants at the markets. However, the higher indoor/outdoor ratios demonstrated that the operation of air conditioning had influence on the levels of bacteria at the markets. It was found that average PM 10 concentration at poultry stalls was higher than the HKIAQO standard of 180 μg/m 3 , and was over two times that measured at vegetable, fish and meat stalls. Furthermore, the concentration of airborne bacteria at the poultry stalls was as high as 1031 CFU/m 3 , which was above the HKIAQO standard of 1000 CFU/m 3 . The bacteria levels at other three stalls were all below the HKIAQO standard

Transmission of an overdriven plane detonation in lean hydrogen-air mixtures

International Nuclear Information System (INIS)

Desbordes, D.; Lannoy, A.

1988-01-01

This paper deals with hydrogen-air explosions hazards in nuclear power plants, if PWR Loss Of Coolant Accident occurs. The main objective concerns the determination of the size of the critical diameter of transmission of a detonation propagating in a near stoechiometric H 2 -Air mixture. In such a situation the diffracting detonation is an overdriven wave. Laboratory scale simulations are described which emphasize the importance of a negative step of concentration of combustible in a mixture (stoechio to lean) on plane detonation characteristics of the lean mixture, especially the drastric reduction (i) of the size of its inrinsic tridimensional structure and (ii) correlatively that of the critical diameter of transmission of the mixture

Swirling Combustor Energy Converter: H2/Air Simulations of Separated Chambers

Directory of Open Access Journals (Sweden)

Angelo Minotti

2015-09-01

Full Text Available This work reports results related to the “EU-FP7-HRC-Power” project aiming at developing micro-meso hybrid sources of power. One of the goals of the project is to achieve surface temperatures up to more than 1000 K, with a ∆T ≤ 100 K, in order to be compatible with a thermal/electrical conversion by thermo-photovoltaic cells. The authors investigate how to reach that goal adopting swirling chambers integrated in a thermally-conductive and emitting element. The converter consists of a small parallelepiped brick inside two separated swirling meso-combustion chambers, which heat up the parallelepiped, emitting material by the combustion of H2 and air at ambient pressure. The overall dimension is of the order of cm. Nine combustion simulations have been carried out assuming detailed chemistry, several length/diameter ratios (Z/D = 3, 5 and 11 and equivalence ratios (0.4, 0.7 and 1; all are at 400 W of injected chemical power. Among the most important results are the converter surfaces temperatures, the heat loads, provided to the environment, and the chemical efficiency. The high chemical efficiency, h > 99.9%, is due to the relatively long average gas residence time coupled with the fairly good mixing due to the swirl motion and the impinging air/fuel jets that provide heat and radicals to the flame.

Electronic transport behavior of diameter-graded Ag nanowires

International Nuclear Information System (INIS)

Wang Xuewei; Yuan Zhihao

2010-01-01

Ag nanowires with a graded diameter in anodic aluminum oxide (AAO) membranes were fabricated by the direct-current electrodeposition. The Ag nanowires have a graded-change in diameter from 8 to 32 nm, which is matched with the graded-change of the AAO pore diameter. Electronic transport measurements show that there is a transport behavior similar to that of a metal-semiconductor junction along the axial direction in the diameter-graded Ag nanowires. Such a novel homogeneous nanojunction will be of great fundamental and practical significance.

Electronic transport behavior of diameter-graded Ag nanowires

Science.gov (United States)

Wang, Xue Wei; Yuan, Zhi Hao

2010-05-01

Ag nanowires with a graded diameter in anodic aluminum oxide (AAO) membranes were fabricated by the direct-current electrodeposition. The Ag nanowires have a graded-change in diameter from 8 to 32 nm, which is matched with the graded-change of the AAO pore diameter. Electronic transport measurements show that there is a transport behavior similar to that of a metal-semiconductor junction along the axial direction in the diameter-graded Ag nanowires. Such a novel homogeneous nanojunction will be of great fundamental and practical significance.

Lysosome Transport as a Function of Lysosome Diameter

Science.gov (United States)

Bandyopadhyay, Debjyoti; Cyphersmith, Austin; Zapata, Jairo A.; Kim, Y. Joseph; Payne, Christine K.

2014-01-01

Lysosomes are membrane-bound organelles responsible for the transport and degradation of intracellular and extracellular cargo. The intracellular motion of lysosomes is both diffusive and active, mediated by motor proteins moving lysosomes along microtubules. We sought to determine how lysosome diameter influences lysosome transport. We used osmotic swelling to double the diameter of lysosomes, creating a population of enlarged lysosomes. This allowed us to directly examine the intracellular transport of the same organelle as a function of diameter. Lysosome transport was measured using live cell fluorescence microscopy and single particle tracking. We find, as expected, the diffusive component of intracellular transport is decreased proportional to the increased lysosome diameter. Active transport of the enlarged lysosomes is not affected by the increased lysosome diameter. PMID:24497985

Impact of Dust on Air Quality and Radiative Forcing : AN Episodic Study for the Megacity Istanbul Using RegCM4.1

Science.gov (United States)

Agacayak, T.; Kindap, T.; Unal, A.; Mallet, M.; Pozzoli, L.; Karaca, M.; Solmon, F.

2012-04-01

Istanbul is a megacity (with population over 15 million) that has significant levels of Particulate Matter concentrations. It is suspected that long-range transport of Saharan dust is one of the main contributors. The purpose of this study is to investigate the relationship between high PM concentrations and dust transport using atmospheric modeling, satellite data as well as in-situ observations. Measurements of PM10 concentrations at 10 different stations in Istanbul for the period 2004-2010 were provided by the Turkish Ministry of Environment. Daily mean PM10 concentrations exceeding the European standard of 50 µg/m3 were found to be, on average, 49 days for the Spring period, 45 days for the Winter period, and 41 days for the Fall period. DREAM model output (Nickovic et al. 2001; Perez et al. 2006) suggests that high PM10 concentrations correlate highly with mineral dust transport episodes from Saharan desert (i.e., 23% for winter and 58% for spring). In this study, we have utilized RegCM4.1 model to further investigate the Saharan dust transport in the selected episodes. During the period between March 21st and 24th, 2008, observed daily mean of PM10 concentrations reach up to 140 µg/m3 in Istanbul. Simulations conducted by RegCM4.1 provides AOD (350-640 nm model band) values ranging between 0.04 and 0.98during this episode. Central Anatolia is affected from the dust transport on 21 and 22 March 2008, with a daily mean AOD of 0.9. On 23th March 2008, the dust plume reaches the Marmara Sea and AOD increases about 1.0 over the region according to both DREAM and RegCM4.1 model outputs. On the fourth day of the episode, the dust event stops and AOD decreases to 0.5 over the region. Asymmetry parameters can be seen as 0.62 during the dust episode, while single scattering albedo is about 0.93 during the entire dust episode over Istanbul. The effect of the dust episode on the regional radiative budget over Istanbul was also estimated. Model results indicate a daily

The decay of a lambda particle in the 32 cm hydrogen bubble chamber

CERN Multimedia

1960-01-01

This image from 1960 is of real particle tracks formed in CERN's first liquid hydrogen bubble chamber to be used in experiments. It was a tiny detector by today's standards at only 32 cm in diameter. Negatively charged pions with an energy of 16 GeV enter from the left. One of them interacts with a proton in the liquid hydrogen and creates sprays of new particles, including a neutral particle (a lambda) that decays to produce the "V" of two charged particle tracks at the centre. Lower-energy charged particles produced in the interactions spiral in the magnetic field of the chamber. The invention of bubble chambers in 1952 revolutionized the field of particle physics, allowing real particle tracks to be seen and photographed, after releasing the pressure that had kept a liquid above its normal boiling point.

An experimental study on suspended sodium droplet combustion (3)

International Nuclear Information System (INIS)

Sato, Kenji

2005-03-01

As part of studies for phenomenological investigation of sodium droplet burning behavior, in our previous experimental studies for suspended single sodium droplet, behavior of ignition process and succeeding combustion, ignition delay time, and droplet temperature history had been investigated. In this study, combustion experiments of suspended sodium droplet were performed in upward dry air flow by expanding the range of free-stream velocity U of air flow into 400 cm/s with initial droplet temperature Ti=300, 350, and 400degC and initial droplet diameter 4 mm at first. Then, the combustion experiments were also performed by changing the initial droplet diameter from 2.3 to 4.4 mm with Ti=350 and 400degC and U=100 cm/s. From the experimental results, the effects of free-stream velocity, initial droplet temperature, and initial droplet diameter on the ignition/burning behavior and ignition delay time were examined. The obtained results are as follows: (1) Ignition phenomena of suspended droplet were observed for all examined experimental conditions up to 400 cm/s. The orange emission observed at the moment of ignition occurs simultaneously over whole droplet surface except the top region of it. (2) The feature of the dependence of ignition delay time on the free-stream velocity is independent of the initial droplet temperature. With the increase of the free-stream velocity, up to 300 cm/s the ignition delay time decreases with decreasing dependency, and then the dependency increases more. (3) The ignition delay time increases with the increase of initial droplet diameter. The dependency increases as the initial droplet diameter increases. The ignition delay time extrapolated toward zero diameters from the obtained results becomes to be essentially zero. (author)

Monte Carlo simulation of the effect of miniphantom on in-air output ratio

International Nuclear Information System (INIS)

Li Jun; Zhu, Timothy C.

2010-01-01

Purpose: The aim of the study was to quantify the effect of miniphantoms on in-air output ratio measurements, i.e., to determine correction factors for in-air output ratio. Methods: Monte Carlo (MC) simulations were performed to simulate in-air output ratio measurements by using miniphantoms made of various materials (PMMA, graphite, copper, brass, and lead) and with different longitudinal thicknesses or depths (2-30 g/cm 2 ) in photon beams of 6 and 15 MV, respectively, and with collimator settings ranging from 3x3 to 40x40 cm 2 . EGSnrc and BEAMnrc (2007) software packages were used. Photon energy spectra corresponding to the collimator settings were obtained from BEAMnrc code simulations on a linear accelerator and were used to quantify the components of in-air output ratio correction factors, i.e., attenuation, mass energy absorption, and phantom scatter correction factors. In-air output ratio correction factors as functions of miniphantom material, miniphantom longitudinal thickness, and collimator setting were calculated and compared to a previous experimental study. Results: The in-air output ratio correction factors increase with collimator opening and miniphantom longitudinal thickness for all the materials and for both energies. At small longitudinal thicknesses, the in-air output ratio correction factors for PMMA and graphite are close to 1. The maximum magnitudes of the in-air output ratio correction factors occur at the largest collimator setting (40x40 cm 2 ) and the largest miniphantom longitudinal thickness (30 g/cm 2 ): 1.008±0.001 for 6 MV and 1.012±0.001 for 15 MV, respectively. The MC simulations of the in-air output ratio correction factor confirm the previous experimental study. Conclusions: The study has verified that a correction factor for in-air output ratio can be obtained as a product of attenuation correction factor, mass energy absorption correction factor, and phantom scatter correction factor. The correction factors obtained in the

Tree Height-Diameter Relationships in the Alpine Treeline Ecotone Compared with Those in Closed Forests on Changbai Mountain, Northeastern China

Directory of Open Access Journals (Sweden)

Xiaoyu Wang

2017-04-01

Full Text Available Height-diameter relationship is one of the most important stature characteristics of trees. It will change with climatic conditions because height and diameter growth displays different sensitivities to climatic factors such as temperature. Detecting and understanding changes in the stature of trees growing along altitudinal gradients up to their upper limits can help us to better understand the adaptation strategy of trees under global warming conditions. On Changbai Mountain in northeastern China, height-diameter datasets were collected for 2723 Erman’s birch (Betula ermanii Cham. in the alpine treeline ecotone in 2006 and 2013, and for 888 Erman’s birch, spruce (Picea jezoensis Siebold & Zucc. Carr., larch (Larix olgensis A. Henry, and fir (Abies nephrolepis Trautv. ex Maxim. along an altitudinal gradient below the alpine treeline in 2006. These datasets were utilized to explore both changes in the stature of birch at the alpine treeline over time and variations in tree stature of different tree species across altitudes at a given time point (2006. Results showed that birch saplings (<140 cm in height became stunted while birches with a height of >140 cm became more tapered in the alpine treeline ecotone. The stature of birch along the altitudinal gradient became more tapered from 1700 to 1900 m above see level (a.s.l. and then became more stunted from 1900 to 2050 m a.s.l., with 1900 m a.s.l. being the altitudinal inflection point in this pattern. The treeline birch, due to its great temperature magnitude of distribution, displayed higher stature-plasticity in terms of its height-diameter ratio than the lower elevation species studied. The stature of birch is strongly modulated by altitude-related temperature but also co-influenced by other environmental factors such as soil depth and available water, wind speed, and duration and depth of winter snow cover. The high stature-plasticity of birch makes it fare better than other species to

High-throughput liquid-absorption air-sampling apparatus and methods

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-11

A portable high-throughput liquid-absorption air sampler [PHTLAAS] has an asymmetric air inlet through which air is drawn upward by a small and light-weight centrifugal fan driven by a direct current motor that can be powered by a battery. The air inlet is so configured as to impart both rotational and downward components of motion to the sampled air near said inlet. The PHTLAAS comprises a glass tube of relatively small size through which air passes at a high rate in a swirling, highly turbulent motion, which facilitates rapid transfer of vapors and particulates to a liquid film covering the inner walls of the tube. The pressure drop through the glass tube is < 10 cm of water, usually < 5 cm of water. The sampler's collection efficiency is usually > 20% for vapors or airborne particulates in the 2--3 microns range and > 50% for particles larger than 4 microns. In conjunction with various analyzers, the PHTLAAS can serve to monitor a variety of hazardous or illicit airborne substances, such as lead-containing particulates, tritiated water vapor, biological aerosols, or traces of concealed drugs or explosives.

determination of elemental composition of air particulates and soils

African Journals Online (AJOL)

Mgina

Department of Physics, Faculty of Science. University ... collecting airborne particles with an aerodynamic diameter of 2.5 μm. Energy ... have elevated concentrations compared to the background air levels. ... part of the total mass of street dust,.

Experimental Study of the Slit Spacing and Bed Height on the Thermal Performance of Slit-Glazed Solar Air Heater

Directory of Open Access Journals (Sweden)

Seyyed Mahdi Taheri Mousavi

2017-01-01

Full Text Available The thermal performances of three slit-glazed solar air heaters (SGSAHs were investigated experimentally. Three SGSAHs with different bed heights (7 cm, 5 cm, and 3 cm were fabricated with multiple glass panes used for glazing. The length, width, and thickness of each pane were 154 cm, 6 cm, and 0.4 cm, respectively. Ambient air was continuously withdrawn through the gaps between the glass panes by fans. The experiments were conducted for four different gap distances between the glass panes (0.5 mm, 1 mm, 2 mm, and 3 mm and the air mass flow rate was varied between 0.014 kg/s and 0.057 kg/s. The effects of air mass flux on the outlet temperature and thermal efficiency were studied. For the SGSAH with bed height of 7 cm and glass pane gap distance of 0.5 mm, the highest efficiency was obtained as 82% at a mass flow rate of 0.057 kg/s and the air temperature difference between the inlet and the outlet (∆T was maximum (27°C when the mass flow rate was least. The results demonstrate that for lower mass flow rates and larger gaps, the performance of SGSAH with a bed height of 3 cm was better compared to that of others. However, for higher mass flow rates, the SGSAH with 7 cm bed height performed better.

Experimental study on magnetically insulated transmission line electrode surface evolution process under MA/cm current density

Energy Technology Data Exchange (ETDEWEB)

Zhang, PengFei; Qiu, Aici [State Key Laboratory of Electrical Insulation and Power Equipment, Xi' an Jiaotong University, Xi' an 710049 (China); State Key Laboratory of Intense Pulse Radiation of Simulation and Effect, Northwest Institute of Nuclear Technology, Xi' an 710024 (China); Hu, Yang; Yang, HaiLiang; Sun, Jiang; Wang, Liangping; Cong, Peitian [State Key Laboratory of Intense Pulse Radiation of Simulation and Effect, Northwest Institute of Nuclear Technology, Xi' an 710024 (China)

2016-03-15

The design of high-current density magnetically insulated transmission line (MITL) is a difficult problem of current large-scale Z-pinch device. In particular, a thorough understanding of the MITL electrode surface evolution process under high current density is lacking. On the “QiangGuang-I” accelerator, the load area possesses a low inductance short-circuit structure with a diameter of 2.85 mm at the cathode, and three reflux columns with a diameter of 3 mm and uniformly distributed circumference at the anode. The length of the high density MITL area is 20 mm. A laser interferometer is used to assess and analyze the state of the MITL cathode and anode gap, and their evolution process under high current density. Experimental results indicate that evident current loss is not observed in the current density area at pulse leading edge, and peak when the surface current density reaches MA/cm. Analysis on electrode surface working conditions indicates that when the current leading edge is at 71.5% of the peak, the total evaporation of MITL cathode structure can be realized by energy deposition caused by ohmic heating. The electrode state changes, and diffusion conditions are reflected in the laser interferometer image. The MITL cathode area mainly exists in metal vapor form. The metal vapor density in the cathode central region is higher than the upper limit of laser penetration density (∼4 × 10{sup 21}/cm{sup 3}), with an expansion velocity of ∼0.96 km/s. The metal vapor density in the electrode outer area may lead to evident distortion of fringes, and its expansion velocity is faster than that in the center area (1.53 km/s).

Fabrication and Characterization of Device Pressure Regulation System Orifice of Manufacturing Process Gel Uranium Column Gelation External

International Nuclear Information System (INIS)

Triyono; Sutarni; Indra Suryawan

2009-01-01

The device pressure regulation orifice system of manufacturing process gel uranium on external column gelation has been made and characterized. The device consists : compressor 5.75-6.75 kg / cm 2 , air container tank, power supply 24 volts dc, solenoid valve 24 volts dc, pressure indicator 0-100 mbar, pressure indicator 0-250 mbar, mechanical valve and power electric 380 volts 50 Hz. The activity includes: installation device system and characterization with pressure variation orifice 5-75 mbar on the compressor 5.75-6.5 kg/cm 2 continuously for 1 minute. The method of installation i.e: wiring and piping to first component and support component (compressor and pressure air indicator, air container tank and pressure air indicator, solenoid valve, power supply 220 volts / 24 volts dc and orifice). After apparatus installed has been tested by the characterization without feed under air pressure varied to orifice of 5-75 mbar and device characterization with variation diameter orifice of 0.5-1 mm and orifice pressure of 5-75 mbar. The result in the characterization an every component good function, can be operation by input pressure range of 15-185 mbar orifice pressure range of 5-75 mbar. The characterization result device pressure regulation orifice system showed that: the system can be good operation of air pressure regulation orifice between 5-75 mbar with diameter orifice 0.5 mm to result gelation range of 10-25 piece / minute with variation air pressure input between 15-185 mbar of air pressure compressor 5.75-6.5 kg cm 2 . (author)

Leveraging the NLM map from SNOMED CT to ICD-10-CM to facilitate adoption of ICD-10-CM.

Science.gov (United States)

Cartagena, F Phil; Schaeffer, Molly; Rifai, Dorothy; Doroshenko, Victoria; Goldberg, Howard S

2015-05-01

Develop and test web services to retrieve and identify the most precise ICD-10-CM code(s) for a given clinical encounter. Facilitate creation of user interfaces that 1) provide an initial shortlist of candidate codes, ideally visible on a single screen; and 2) enable code refinement. To satisfy our high-level use cases, the analysis and design process involved reviewing available maps and crosswalks, designing the rule adjudication framework, determining necessary metadata, retrieving related codes, and iteratively improving the code refinement algorithm. The Partners ICD-10-CM Search and Mapping Services (PI-10 Services) are SOAP web services written using Microsoft's.NET 4.0 Framework, Windows Communications Framework, and SQL Server 2012. The services cover 96% of the Partners problem list subset of SNOMED CT codes that map to ICD-10-CM codes and can return up to 76% of the 69,823 billable ICD-10-CM codes prior to creation of custom mapping rules. We consider ways to increase 1) the coverage ratio of the Partners problem list subset of SNOMED CT codes and 2) the upper bound of returnable ICD-10-CM codes by creating custom mapping rules. Future work will investigate the utility of the transitive closure of SNOMED CT codes and other methods to assist in custom rule creation and, ultimately, to provide more complete coverage of ICD-10-CM codes. ICD-10-CM will be easier for clinicians to manage if applications display short lists of candidate codes from which clinicians can subsequently select a code for further refinement. The PI-10 Services support ICD-10 migration by implementing this paradigm and enabling users to consistently and accurately find the best ICD-10-CM code(s) without translation from ICD-9-CM. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Production and Characterization of Femtosecond-Laser-Induced Air Plasma

National Research Council Canada - National Science Library

Armbruster, David R

2008-01-01

.... A beam expander was used to expand the beam to a diameter of approximately 6.5 mm, and the beam was focused through a 25 mm focal length achromatic lens to produce laser-induced plasma in ambient air...

Size and spatial distribution of micropores in SBA-15 using CM-SANS

International Nuclear Information System (INIS)

Pollock, Rachel A.; Walsh, Brenna R.; Fry, Jason A.; Ghampson, Tyrone; Centikol, Ozgul; Melnichenko, Yuri B.; Kaiser, Helmut; Pynn, Roger; Frederick, Brian G.

2011-01-01

Diffraction intensity analysis of small-angle neutron scattering measurements of dry SBA-15 have been combined with nonlocal density functional theory (NLDFT) analysis of nitrogen desorption isotherms to characterize the micropore, secondary mesopore, and primary mesopore structure. The radial dependence of the scattering length density, which is sensitive to isolated surface hydroxyls, can only be modeled if the NLDFT pore size distribution is distributed relatively uniformly throughout the silica framework, not localized in a 'corona' around the primary mesopores. Contrast matching-small angle neutron scattering (CM-SANS) measurements, using water, decane, tributylamine, cyclohexane, and isooctane as direct probes of the size of micropores indicate that the smallest pores in SBA-15 have diameter between 5.7 and 6.2 (angstrom). Correlation of the minimum pore size with the onset of the micropore size distribution provides direct evidence that the shape of the smallest micropores is cylinderlike, which is consistent with their being due to unraveling of the polymer template.

Carbon dioxide degassing in fresh and saline water. II: Degassing performance of an air-lift

DEFF Research Database (Denmark)

Moran, Damian

2010-01-01

A study was undertaken to measure the efficiency with which carbon dioxide was stripped from freshwater (0‰) and saline water (35‰ NaCl) passing through an air-lift at 15 °C. The air-lift was constructed of 50 mm (OD) PVC pipe submerged 95 cm in a tank, had an adjustable air injection rate, and c...... for any water type (i.e. temperature, alkalinity, salinity and influent CO2 concentration).......A study was undertaken to measure the efficiency with which carbon dioxide was stripped from freshwater (0‰) and saline water (35‰ NaCl) passing through an air-lift at 15 °C. The air-lift was constructed of 50 mm (OD) PVC pipe submerged 95 cm in a tank, had an adjustable air injection rate......, and could be adjusted to three lifting heights: 11, 16 and 25 cm. The gas to liquid ratio (G:L) was high (1.9–2.0) at low water discharge rates (Qw) and represented the initial input energy required to raise the water up the vertical riser section to the discharge pipe. The air-lift increased in pumping...

Morphometric study of uninvolved rectal mucosa 10 cm and 20 cm away from the malignant tumor.

Science.gov (United States)

Despotović, Sanja Z; Milićević, Novica M; Milosević, Dragoslav P; Despotović, Nebojsa; Erceg, Predrag; Bojić, Bozidar; Bojić, Danijela; Svorcan, Petar; Mihajlović, Gordana; Dorđević, Jelena; Lalić, Ivana M; Milićević, Zivana

2014-02-01

Recently, many details of the interplay between tumor cells and tumor-associated stromal elements leading to the progression of malignant disease were elucidated. In contrast, little is known about the role of uninvolved stromal tissue in the remote surrounding of the malignant tumor. Therefore, we performed a computer-aided morphometric study of rectal mucosa in samples taken 10 cm and 20 cm away from the malignant tumor during endoscopic examination of 23 patients older than 60 years. The samples of rectal mucosa from 10 healthy persons of corresponding age subjected to diagnostic rectoscopy during active screening for asymptomatic cancer were used as control. All structural elements of the rectal mucosa were studied and the number of nucleated cells in the lamina propria per 0.1 mm² of tissue was assessed. Our study revealed a reduced number of cells in the lamina propria of the rectal mucosa 10 cm and 20 cm away from the tumor lesion in both male and female patients. The decreased mucosal height and increased crypt number were registered in female patients 10 cm away from the tumor. The connective tissue of lamina propria showed a disorderly organization: the collagen fibers were frail, loosely arranged and signs of tissue edema were present. Small blood vessels and capillaries were much more frequently seen than in healthy tissue. Our results demonstrate the complex interactions between the cancer and remote mucosal tissue of the affected organ.

Air Quality in Lanzhou, a Major Industrial City in China: Characteristics of Air Pollution and Review of Existing Evidence from Air Pollution and Health Studies

Science.gov (United States)

Zhang, Yaqun; Li, Min; Bravo, Mercedes A.; Jin, Lan; Nori-Sarma, Amruta; Xu, Yanwen; Guan, Donghong; Wang, Chengyuan; Chen, Mingxia; Wang, Xiao; Tao, Wei; Qiu, Weitao; Zhang, Yawei

2015-01-01

Air pollution contributes substantially to global health burdens; however, less is known about pollution patterns in China and whether they differ from those elsewhere. We evaluated temporal and spatial heterogeneity of air pollution in Lanzhou, an urban Chinese city (April 2009–December 2012), and conducted a systematic review of literature on air pollution and health in Lanzhou. Average levels were 141.5, 42.3, and 47.2 µg/m3 for particulate matter with an aerodynamic diameter ≤10 µm (PM10), NO2, and SO2, respectively. Findings suggest some seasonality, particularly for SO2, with higher concentrations during colder months relative to warmer months, although a longer time frame of data is needed to evaluate seasonality fully. Correlation coefficients generally declined with distance between monitors, while coefficients of divergence increased with distance. However, these trends were not statistically significant. PM10 levels exceeded Chinese and other health-based standards and guidelines. The review identified 13 studies on outdoor air pollution and health. Although limited, the studies indicate that air pollution is associated with increased risk of health outcomes in Lanzhou. These studies and the high air pollution levels suggest potentially serious health consequences. Findings can provide guidance to future epidemiological studies, monitor placement programs, and air quality policies. PMID:25838615

Continuous scanning of the mobility and size distribution of charged clusters and nanometer particles in atmospheric air and the Balanced Scanning Mobility Analyzer BSMA

Science.gov (United States)

Tammet, H.

2006-12-01

Measuring of charged nanometer particles in atmospheric air is a routine task in research on atmospheric electricity, where these particles are called the atmospheric ions. An aspiration condenser is the most popular instrument for measuring atmospheric ions. Continuous scanning of a mobility distribution is possible when the aspiration condenser is connected as an arm of a balanced bridge. Transfer function of an aspiration condenser is calculated according to the measurements of geometric dimensions, air flow rate, driving voltage, and electric current. The most complicated phase of the calibration is the estimation of the inlet loss of ions due to the Brownian deposition. The available models of ion deposition on the protective inlet screen and the inlet control electrofilter have the uncertainty of about 20%. To keep the uncertainty of measurements low the adsorption should not exceed a few tens of percent. The online conversion of the mobility distribution to the size distribution and a correct reduction of inlet losses are possible when air temperature and pressure are measured simultaneously with the mobility distribution. Two instruments called the Balanced Scanning Mobility Analyzers (BSMA) were manufactured and tested in routine atmospheric measurements. The concentration of atmospheric ions of the size of about a few nanometers is very low and a high air flow rate is required to collect enough of ion current. The air flow of 52 l/s exceeds the air flow in usual aerosol instruments by 2-3 orders of magnitude. The high flow rate reduces the time of ion passage to 60 ms and the heating of air in an analyzer to 0.2 K, which suppresses a possible transformation of ions inside the instrument. The mobility range of the BSMA of 0.032-3.2 cm 2 V - 1 s - 1 is logarithmically uniformly divided into 16 fractions. The size distribution is presented by 12 fractions in the diameter range of 0.4-7.5 nm. The measurement noise of a fraction concentration is typically

Study on the role of active radicals on plasma sterilization inside small diameter flexible polymeric tubes

Science.gov (United States)

Mstsuura, Hiroto; Fujiyama, Takatomo; Okuno, Yasuki; Furuta, Masakazu; Okuda, Shuichi; Takemura, Yuichiro

2015-09-01

Recently, atmospheric pressure discharge plasma has gathered attention in various fields. Among them, plasma sterilization with many types of plasma source has studied for decades and its mechanism is still an open question. If active radicals produced in plasma has main contribution of killing bacterias, direct contact of the so-called plasma flame might not be necessary. To confirm this, sterilization inside small diameter flexible polymeric tubes is studied in present work. DBD type plasma jet is produce by flowing helium gas in a glass tube. A long polymeric tube is connected and plasma jet is introduced into it. Plasma flame length depends on helium gas flow rate, but limited to about 10 cm in our experimental condition. E.colis set at the exit plasma source is easily killed during 10 min irradiation. At the tube end (about 20 cm away from plasma source exit), sterilization is possible with 30 min operation. This result shows that active radical is produced with helium plasma and mist contained in sample, and it can be transferred more than 20 cm during it life time. More plasma diagnostic data will also be shown at the conference. This work was partially supported by the ''ZE Research Program, IAE(ZE27B-4).

The microbiological quality of air improves when using air conditioning systems in cars.

Science.gov (United States)

Vonberg, Ralf-Peter; Gastmeier, Petra; Kenneweg, Björn; Holdack-Janssen, Hinrich; Sohr, Dorit; Chaberny, Iris F

2010-06-01

Because of better comfort, air conditioning systems are a common feature in automobiles these days. However, its impact on the number of particles and microorganisms inside the vehicle--and by this its impact on the risk of an allergic reaction--is yet unknown. Over a time period of 30 months, the quality of air was investigated in three different types of cars (VW Passat, VW Polo FSI, Seat Alhambra) that were all equipped with a automatic air conditioning system. Operation modes using fresh air from outside the car as well as circulating air from inside the car were examined. The total number of microorganisms and the number of mold spores were measured by impaction in a high flow air sampler. Particles of 0.5 to 5.0 microm diameter were counted by a laser particle counter device. Overall 32 occasions of sampling were performed. The concentration of microorganisms outside the cars was always higher than it was inside the cars. Few minutes after starting the air conditioning system the total number of microorganisms was reduced by 81.7%, the number of mold spores was reduced by 83.3%, and the number of particles was reduced by 87.8%. There were no significant differences neither between the types of cars nor between the types of operation mode of the air conditioning system (fresh air vs. circulating air). All parameters that were looked for in this study improved during utilization of the car's air conditioning system. We believe that the risk of an allergic reaction will be reduced during use also. Nevertheless, we recommend regular maintenance of the system and replacement of older filters after defined changing intervals.

Laser direct writing using submicron-diameter fibers.

Science.gov (United States)

Tian, Feng; Yang, Guoguang; Bai, Jian; Xu, Jianfeng; Hou, Changlun; Liang, Yiyong; Wang, Kaiwei

2009-10-26

In this paper, a novel direct writing technique using submicron-diameter fibers is presented. The submicron-diameter fiber probe serves as a tightly confined point source and it adopts micro touch mode in the process of writing. The energy distribution of direct writing model is analyzed by Three-Dimension Finite-Difference Time-Domain method. Experiments demonstrate that submicron-diameter fiber direct writing has some advantages: simple process, 350-nm-resolution (lower than 442-nm-wavelength), large writing area, and controllable width of lines. In addition, by altering writing direction of lines, complex submicron patterns can be fabricated.

Angiographic Evaluation of Carotid Artery Grafting with Prefabricated Small-Diameter, Small-Intestinal Submucosa Grafts in Sheep

International Nuclear Information System (INIS)

Pavcnik, Dusan; Obermiller, Josef; Uchida, Barry T.; Van Alstine, William; Edwards, James M.; Landry, Gregory J.; Kaufman, John A.; Keller, Frederick S.; Roesch, Josef

2009-01-01

The purpose of this study was to report the longitudinal angiographic evaluation of prefabricated lyophilized small-intestinal submucosa (SIS) grafts placed in ovine carotid arteries and to demonstrate a variety of complications that developed. A total of 24 grafts, 10 cm long and 6 mm in diameter, were placed surgically as interposition grafts. Graft patency at 1 week was evaluated by Doppler ultrasound, and angiography was used for follow-up at 1 month and at 3 to 4 months. A 90% patency rate was found at 1 week, 65% at 1 month, and 30% at 3 to 4 months. On the patent grafts, angiography demonstrated a variety of changes, such as anastomotic stenoses, graft diffuse dilations and dissections, and aneurysm formation. These findings have not been previously demonstrated angiographically by other investigators reporting results with small-diameter vessel grafts made from fresh small-intestinal submucosa (SIS). The complications found were partially related to the graft construction from four SIS layers. Detailed longitudinal angiographic study should become an essential part of any future evaluation of small-vessel SIS grafting.

High-temperature hydrogen-air-steam detonation experiments in the BNL small-scale development apparatus

International Nuclear Information System (INIS)

Ciccarelli, G.; Ginsberg, T.; Boccio, J.; Economos, C.; Finfrock, C.; Gerlach, L.; Sato, K.

1994-01-01

The Small-Scale Development Apparatus (SSDA) was constructed to provide a preliminary set of experimental data to characterize the effect of temperature on the ability of hydrogen-air-steam-mixtures to undergo detonations and, equally important, to support design of the larger-scale High-Temperature Combustion Facility (HTCF) by providing a test bed for solution of a number of high-temperature design and operational problems. The SSDA, the central element of which is 10-cm inside diameter, 6.1-m long tubular test vessel designed to permit detonation experiments at temperatures up to 700K, was employed to study self-sustained detonations in gaseous mixtures of hydrogen, air, and steam at temperature between 300K and 650K at a fixed pressure of 0.1 MPa. Detonation cell size measurements provide clear evidence that the effect of hydrogen-air gas mixture temperature, in the range 300K to 650K, is to decrease cell size and, hence, to increase the sensitivity of the mixture to undergo detonations. The effect of steam content, at any given temperature, is to increase the cell size and, thereby, to decrease the sensitivity of stoichiometric hydrogen-air mixtures. The one-dimensional ZND model does a very good job at predicting the overall trends in the cell size data over the range of hydrogen-air-steam mixture compositions and temperature studied in the experiments. Experiments were conducted to measure the rate of hydrogen oxidation in the absence of ignition sources at temperatures of 500K and 650K, for hydrogen-air mixtures of 15% and 50%, and for a mixture of equimolar hydrogen-air and 30% steam at 650K. The rate of hydrogen oxidation was found to be significant at 650K. Reduction of hydrogen concentration by chemical reaction from 50 to 44% hydrogen, and from 15 to 11% hydrogen, were observed on a time frame of minutes. The DeSoete rate equation predicts the 50% experiment very well, but greatly underestimates the reaction rate of the lean mixtures

A comparison between the dimensions of positive transtibial residual limb molds prepared by air pressure casting and weight-bearing casting methods.

Science.gov (United States)

Hajiaghaei, Behnam; Ebrahimi, Ismail; Kamyab, Mojtaba; Saeedi, Hassan; Jalali, Maryam

2016-01-01

Creating a socket with proper fit is an important factor to ensure the comfort and control of prosthetic devices. Several techniques are commonly used to cast transtibial stumps but their effect on stump shape deformation is not well understood. This study compares the dimensions, circumferences and volumes of the positive casts and also the socket comfort between two casting methods. Our hypothesis was that the casts prepared by air pressure method have less volume and are more comfortable than those prepared by weight bearing method. Fifteen transtibial unilateral amputees participated in the study. Two weight bearing and air pressure casting methods were utilized for their residual limbs. The diameters and circumferences of various areas of the residual limbs and positive casts were compared. The volumes of two types of casts were measured by a volumeter and compared. Visual Analogue Scale (VAS) was used to measure the sockets fit comfort. Circumferences at 10 and 15 cm below the patella on the casts were significantly smaller in air pressure casting method compared to the weight bearing method (p=0.00 and 0.01 respectively). The volume of the cast in air pressure method was lower than that of the weight bearing method (p=0.006). The amputees found the fit of the sockets prepared by air pressure method more comfortable than the weight bearing sockets (p=0.015). The air pressure casting reduced the circumferences of the distal portion of residual limbs which has more soft tissue and because of its snug fit it provided more comfort for amputees, according to the VAS measurements.

Growth and development of moringa (Moringa oleifera L. stem cuttings as affected by diameter magnitude, growth media, and indole-3-butyric acid

Directory of Open Access Journals (Sweden)

Shamsuddeen Rufai

2016-12-01

Full Text Available The acknowledged status of Moringa oleifera L. in sub-Saharan Africa, especially western Africa, has of recent accorded it the significance of being a good source of income to a large segment of many of its populace. Intensification of research into the realization of its full economic potential will be of utmost value to impoverished societies globally. One way to achieve this is the full exploration of all possible means that will facilitate its successful growth, propagation, and domestication. Even though it can be successfully raised through seeds, the high level outcrossing (64.3% observed is a hindrance to realization of true to type trees. Vegetative propagation can be employed as an option to tackle the noted limitation, ease the cultivation process, and achieve the required realization of its economic potential. Our trial was carried out to study the influence of two growth media and three levels of indole 3-butyric acid (IBA on root and shoot development in cuttings taken from a coppiced moringa tree existent in Universiti Putra Malaysia. Semi-hardwood cuttings of moringa, of between 20 and 30 mm diameter, cut into 25 cm length, were obtained, rinsed with a fungicide, then dipped, through their basal portion, inside varying levels (0, 1000, 2000, and 3000 ppm of indole-3-butyric acid (IBA for between 7 and 10 seconds. The treated cuttings were then transplanted into a polyethylene bags (23 cm × 36 cm, containing two growth media - a munchong series soil (M and a combination of a munchong series soil thoroughly mixed with biochar (MB in a 3:1 ratio sequence. The trial was conducted inside a shade house where the humidity of the experimental area was manipulated through a regular daily manual hand sprinkling. Plant height, percentage of primary branch produced, leaf area, and dry matter (DM were found to be significantly (P<0.05 influenced by variation in stem diameter magnitude, while the diameter of the primary branch and spad

Measurements of higher order modes in a 30 cm long X-band structure

International Nuclear Information System (INIS)

Xiao, L.; Liang, Y.; Tong, D.; Zhang, H.

2001-01-01

The use of a cage of metallic wires as a bead is proposed to measure the higher order modes (HOMs) in an X-band accelerating structure. These long thin wires can isolate the longitudinal electric field component from other field components and produce sufficient frequency shift in bead-pull measurements. In the setup described in this paper, the bead is made by sputtering silver film onto a thin nylon line through a specially designed fixture. The cage has a size of approximately 0.5 mm in diameter, 2 mm in length and more than six metallic wires of less than 0.1 mm in width. The fabrication and calibration of the cage are described. The longitudinal electric fields of the lowest passband dipole mode TM 110 in a 30 cm long X-band structure are measured by bead-pull measurements. Results are compared with the calculated ones obtained from URMELT-code

Water fog inerting of hydrogen-air mixtures

International Nuclear Information System (INIS)

Zalosh, R.G.; Bajpai, S.N.

1982-01-01

Laboratory tests have been conducted to determine the effects of water fog density, droplet diameter and temperature on the lower flammable limit (LFL) of hydrogen-air-steam mixtures. Five different fog nozzles were used to generate dense fogs with volume mean drop diameters ranging from 20 micro-meters to 115 micro-meters. At 20 0 C, these nozzles marginally raised the hydrogen LFL from 4.0 vol.% hydrogen to typically 4.8%, with one exceptional nozzle producing an LFL of 7.2%. At 50 0 C, the LFL in the presence of dense fog ranged from 5.0 to 7.9%, while at 70 0 C, the range was 5.9 to 8.5%. Fog densities required to achieve a given level of partial inerting increased with approximately the second power of average drop diameter, as predicted by a theoretical flame quenching analysis

Sistem Pengolahan Air Laut Menjadi Air Minum Menggunakan Tenaga Matahari

Directory of Open Access Journals (Sweden)

Iswadi Iswadi

2013-07-01

Full Text Available Has done research about the system of purification of sea water into drinking water using solar energy. Utilization of solar energy as power naturally adopts the system of evaporation that occurs in a siklur water. Design and construction of tools created in the shape of a pyramid so that the absorption of thermal energy from the Sun can be maximum. Methods of work of the system is very simple, namely the souls imprisoned in the air that the pyramid would experience an increase in temperature significantly along with the searing Sun. The temperature of the hot air in the space pyramid is causing sea water which is at the bottom (floor pyramid will evaporate and stick on the wall side of the inside of the pyramid. With the help of gravity, the water vapour will fall in the form of green ears water down the wall of the pyramid. The water will flow through the channel leading into the shelter is. This water is not already contain salt and pure water is so that it can be consumed directly. The results showed that the pyramid with size 160 cm x 160 cm 3 mm fiberglass-wall capable of producing fresh water as much as 2,100 mL. These results have been tested in the laboratory with a result salinity = 0,0 at T = 29,4 °C; TDS = 11 mg/L, 22.2 ms/cm conductivity, at T = 29.3 °C, no taste and no smell.

Normal ureteral diameter in infancy and childhood

International Nuclear Information System (INIS)

Hellstroem, M.; Hjaelmaas, K.; Jacobsson, B.; Jodal, U.; Oden, A.; Oestra Sjukhuset, Goeteborg; Oestra Sjukhuset, Goeteborg; Goeteborg Univ.

1985-01-01

Ureteral diameters were estimated on films from intravenous urography in 194 children (100 boys and 94 girls) aged 0-16 years. Children with signs of urinary tract infection, calculi, obstruction, duplication or malformation were excluded. Films obtained without abdominal compression were used for measurements, including only ureters visualized over 50 per cent of their lengths. A good correlation was demonstrated between ureteral diameter and age and between ureteral diameter and the length of a segment of the lumbar spine. The widest part of the ureter was most often located just above the crossing of the iliac vessels. The right ureter was slightly wider than the left one. No difference between boys and girls was noted. The results are in good agreement with those of others obtained at autopsy. Bearing in mind the possible physiologic variations, it would seem that measuring the ureteral diameter can be of value for a more objective differentiation between dilated and non-dilated ureters. (orig.)

UV laser cleaving of air-polymer structured fibre

NARCIS (Netherlands)

Canning, J.; Buckley, E.; Groothoff, N.; Luther-Davies, B.; Zagari, J.

2002-01-01

The demonstration of ultraviolet (UV) laser ablation technique for cleaving of air-polymer structure (APF) fiber was presented. ArF exciplex laser with an unstable resonator cavity with pulse-to-pulse intensity fluctuations was used for the study. The thermal diffusion time across a 200 µm diameter

A phenomenological model of two-phase (air/fuel droplet developing and breakup

Directory of Open Access Journals (Sweden)

Pavlović Radomir R.

2013-01-01

Full Text Available Effervescent atomization namely the air-filled liquid atomization comprehends certain complex two-phase phenomenon that are difficult to be modeled. Just a few researchers have found the mathematical expressions for description of the complex atomization model of the two-phase mixture air/diesel fuel. In the following review, developing model of twophase (air/fuel droplet of Cummins spray pump-injector is shown. The assumption of the same diameters of the droplet and the opening of the atomizer is made, while the air/fuel mass ratio inside the droplet varies.

[Verification of bacteriological safety of PCM 40 air conditioner].

Science.gov (United States)

Dumas, J L; Ducel, G; Rouge, J C

1991-01-01

This study assessed the bacteriological safety of the bedside air conditioner PCM 40 (Howorth Airtech), used for prevention of intraoperative hypothermia, by blowing filtered warm air through a special mattress. The 3 microns bacterial filter of the device released 2,968 +/- 5,618 particles of diameter less than 3 microns per m3 of room air, containing 78,798 +/- 37,243 of such particles per m3. The amount of bacteries in the air pulsed from the mattress was 30 +/- 41 cfu/m3 vs 120 cfu/m3 in the ambient air and in the hot air supply tubing it reached 6 +/- 5 cfu/m3 vs 175 +/- 77 cfu/m3. It is concluded that bacteriological data do not contra-indicate the use of this air conditioner in the operating theater. The only limitations for use are the position (prone or lateral position) and type of surgery (neurosurgery).

Diameter Growth, Biological Rotation Age and Biomass of Chinese Fir in Burning and Clearing Site Preparations in Subtropical China

Directory of Open Access Journals (Sweden)

Hua Zhou

2016-08-01

Full Text Available Sustained forest management of Cunninghamia lanceolata (Chinese fir plantations in subtropical China is restricted by the limited availability of quantitative data. This study combines inventory data and tree-ring analysis of Chinese fir from natural and plantation forests that were subjected to controlled burning or brush clearing site preparations. Inter-annual variation of Chinese fir tree-ring widths were measured for the controlled burning, brush clearing and natural forest sites. The mean annual diametric growth of Chinese fir was 0.56 cm·year−1 for the natural forest, 0.80 cm·year−1 for the brush clearing site and 1.10 cm·year−1 for the controlled burning site. The time needed to reach the minimum cutting/logging diameter of 15 cm was 14 years in the controlled burning site, 19 years in the brush clearing site and >40 years in the natural forest. The biological rotation ages for the burning, cutting and natural forest sites were 15, 26 and >100 years, respectively. The total aboveground biomasses for the burning and clearing sites were 269.8 t·ha−1 and 252 t·ha−1, respectively. These results suggest that the current 25-year cutting cycle greatly underestimates the growth rate of Chinese fir plantations.

Richness and Abundance of Lianas with Different Diameter Classes in Permanent Plots in the Amazon in Mato Grosso

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D. G. Ferraz

2013-11-01

Full Text Available Lianas are an important component of the structure and diversity of tropical forests and the Amazon biome is one of few natural protected areas that still support the highest level of biodiversity in the world. Generally in disturbed forests high densities of lianas are found than mature forests. The aim of this study is to investigate the richness among families and lianas abundance with different diameter classes in permanent plots in the Amazon of Mato Grosso. To the survey were placed 8 plots of 40 x 250 in a forest fragment that has been management for 30 years, where we sampled lianas species with diameter breast height (DBH ≥ 1 cm. There were sampled 3970 stems in the permanent plots, and the two most abundant were 2 and 6 with 594 and 573 individuals respectively. The richest families were Sapindaceae, Dilleniaceae, Menispermaceae and Fabaceae. These results confirm the hypothesis that disturbed areas have more density of lianas with small DBH.

Simulation evaluation of NIST air-kerma rate calibration standard for electronic brachytherapy.

Science.gov (United States)

Hiatt, Jessica R; Rivard, Mark J; Hughes, H Grady

2016-03-01

Dosimetry for the model S700 50 kV electronic brachytherapy (eBT) source (Xoft, Inc., a subsidiary of iCAD, San Jose, CA) was simulated using Monte Carlo (MC) methods by Rivard et al. ["Calculated and measured brachytherapy dosimetry parameters in water for the Xoft Axxent x-ray source: An electronic brachytherapy source," Med. Phys. 33, 4020-4032 (2006)] and recently by Hiatt et al. ["A revised dosimetric characterization of the model S700 electronic brachytherapy source containing an anode-centering plastic insert and other components not included in the 2006 model," Med. Phys. 42, 2764-2776 (2015)] with improved geometric characterization. While these studies examined the dose distribution in water, there have not previously been reports of the eBT source calibration methods beyond that recently reported by Seltzer et al. ["New national air-kerma standard for low-energy electronic brachytherapy sources," J. Res. Natl. Inst. Stand. Technol. 119, 554-574 (2014)]. Therefore, the motivation for the current study was to provide an independent determination of air-kerma rate at 50 cm in air K̇air(d=50 cm) using MC methods for the model S700 eBT source. Using CAD information provided by the vendor and disassembled sources, an MC model was created for the S700 eBT source. Simulations were run using the mcnp6 radiation transport code for the NIST Lamperti air ionization chamber according to specifications by Boutillon et al. ["Comparison of exposure standards in the 10-50 kV x-ray region," Metrologia 5, 1-11 (1969)], in air without the Lamperti chamber, and in vacuum without the Lamperti chamber. K̇air(d=50 cm) was determined using the *F4 tally with NIST values for the mass energy-absorption coefficients for air. Photon spectra were evaluated over 2 π azimuthal sampling for polar angles of 0° ≤ θ ≤ 180° every 1°. Volume averaging was averted through tight radial binning. Photon energy spectra were determined over all polar angles in both air and vacuum using

Preliminary investigation of aluminum combustion in air and steam.

OpenAIRE

Hallenbeck, Amos Edward.

1983-01-01

Approved for public release; distribution in unlimited. The goal of the experiment is to understand the role of metal-steam combustion in the explosion of underwater shaped cnarges. An apparatus was constructed to investigate combustion of aluminum in stes.m. For background information, aluminum wires (1 mm diameter, 50 mm length) were ignited in air by high current (480 amperes) . Tests in air and steam were photographed using 35 mm color slides and 16 mm movies (4300 fr...

Motion of air bubbles in stagnant water condition

International Nuclear Information System (INIS)

Bezdegumeli, U.; Ozdemir, S.; Yesin, O.

2004-01-01

Full text: In this study, air bubble motion in stagnant water condition in a vertical pipe is investigated experimentally. For this purpose, a test set-up was designed and constructed. Motions of single bubbles, having different diameters in the range of 3.0-4.8 mm, were recorded by using a monochrome camera, an image capture card and a PC. Recorded video images were processed to analyse bubble motion and to obtain the necessary data. The purpose of the study is to determine the variation of bubble axial velocity and bubble drag coefficient as a function of equivalent bubble diameter and bubble Reynolds number, Re b . Therefore, detailed information for this range of bubble diameters was obtained. The results have shown good consistency with the previous studies found in the literature

Diâmetro de estacas e substratos na propagação vegetativa de maniçoba, Manihot glaziovii Muell. Arg Diameter of cuttings and substrates in the vegetative propagation of maniçoba Manihot glaziovii Muell. Arg

Directory of Open Access Journals (Sweden)

Leonardo Elias Ferreira

2010-09-01

Full Text Available Objetivou-se com este trabalho estudar a influência do diâmetro das estacas e dos substratos na propagação vegetativa de maniçoba, Manihot glaziovii Muell. Arg. Utilizou-se o delineamento em blocos casualizados em esquema fatorial 10 x 3, sendo 10 substratos e 3 diâmetros de estacas, totalizando 30 tratamentos, oriundos das combinações entre substratos e diâmetros de estacas, com 4 repetições e 8 estacas por parcela. Os diâmetros das estacas corresponderam a: 0,5 a 1,0 cm (D1; 1,1 a 2,0 cm (D2 e 2,1 a 3,0 cm (D3. Foram utilizados 10 substratos: terra (S1; areia (S2; terra+areia: 1:1 (S3; terra+areia: 2:1 (S4; terra+areia: 1:2 (S5; terra+esterco: 1:1 (S6; areia+esterco: 1:1 (S7; terra+esterco: 2:1 (S8; areia+esterco: 2:1 (S9 e terra+areia+esterco: 1:1:1 (S10. As estacas lenhosas foram retiradas de plantas matrizes em repouso vegetativo, com comprimento de 25 cm e base cortada em bisel. Avaliou-se: percentual de estacas enraizadas; número de raízes; número de brotações; diâmetro e comprimento das brotações; número de folhas; massa seca das brotações e massa seca das raízes, obtidos aos 70 dias após instalação do experimento. Os melhores resultados para todas as variáveis estudadas foram obtidos com estacas de diâmetros entre 1,1 a 2,0 cm e entre 2,1 a 3,0 cm, com substratos que incluíram areia + esterco na sua composição. Tais tratamentos proporcionaram percentagens de enraizamento da ordem de 70 a 80%.This study aims to evaluate substrates and cuttings diameter influence in the vegetative propagation of Manihot glaziovii Muell.Arg. A design in randomized blocks using a 10 x 3 factorial scheme was used, being 10 substrates and 3 cuttings diameter, totaling 30 treatments, from the combinations between substrates and cuttings diameter, with 4 replications and 8 cuttings per plot. Diameters corresponded: 0.5 to 1.0 cm (D1; 1.1 to 2.0 cm (D2 and 2.1 to 3.0 cm (D3. Substrates used were: soil (S1; sand (S2; soil + sand: 1

The impact of mass flow and masking on the pressure drop of air filter in heavy-duty diesel engine

Directory of Open Access Journals (Sweden)

Gorji-Bandpy Mofid

2012-04-01

Full Text Available This paper presents a computational fluid dynamics (CFD calculation approach to predict and evaluate the impact of the mass-flow inlet on the pressure drop of turbocharger`s air filtfer in heavy-duty diesel engine. The numerical computations were carried out using a commercial CFD program whereas the inlet area of the air filter consisted of several holes connected to a channel. After entering through the channel, the air passes among the holes and enters the air filter. The effect of masking holes and hydraulic diameter is studied and investigated on pressure drop. The results indicate that pressure drop increase with decreasing of hydraulic diameter and masking of the holes has considerable affect on the pressure drop.

Gasification Performance of a Top-Lit Updraft Cook Stove

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Yogesh Mehta

2017-10-01

Full Text Available This paper reports on an experimental study of a top-lit updraft cook stove with a focus on gasification. The reactor is operated with primary air only. The performance is studied for a variation in the primary airflow, as well as reactor geometry. Temperature in the reactor, air flow rate, fuel consumption rate, and producer gas composition were measured. From the measurements the superficial velocity, pyrolysis front velocity, peak bed temperature, air fuel ratio, heating value of the producer gas, and gasification rate were calculated. The results show that the producer gas energy content was maximized at a superficial velocity of 9 cm/s. The percent char remaining at the end of gasification decreased with increasing combustion chamber diameter. For a fixed superficial velocity, the gasification rate and producer gas energy content were found to scale linearly with diameter. The energy content of the producer gas was maximized at an air fuel (AF ratio of 1.8 regardless of the diameter.

Actinide nuclides in environmental air and precipitation samples after the Chernobyl accident

International Nuclear Information System (INIS)

Rosner, G.; Hoetzl, H.; Winkler, R.

1988-01-01

The present paper describes the analysis of isotopes of uranium, neptunium, plutonium, americium and curium, in air and deposition samples taken at our laboratory site 10 km north of Munich, subsequent to the Chernobyl accident. Uranium-234, 237 U, 238 U, 239 Np, 238 Pu, 239+240 Pu and 242 Cm have been identified and upper limits of detection have been established for 241 Am and 244 Cm. Deposition and air concentration values are discussed. 12 refs., 1 fig., 2 tabs

Hot-film anemometry in air-water flow

International Nuclear Information System (INIS)

Delahaye, J.M.; Galaup, J.P.

1975-01-01

Local measurements of void fraction and liquid velocity in a steady-state air-water bubbly flow at atmospheric pressure are presented. Use was made of a constant temperature anemometer and of a conical hot-film probe. The signal was processed with a multi-channel analyzer. Void fraction and liquid velocities are determined from the amplitude histogram of the signal. The integrated void fraction over a diameter is compared with the average void fraction along the same diameter obtained with a γ-ray absorption method. The liquid volumetric flow-rate is calculated from the void fraction and liquid velocity profiles and compared with the indication given by a turbine flowmeter [fr

Self-assembling nano-diameter needlelike pinning centers in YBCO, utilizing a foreign element dopant

Energy Technology Data Exchange (ETDEWEB)

Sawh, Ravi-Persad [Texas Center for Superconductivity and Physics Department, University of Houston, 632 Science and Research Bldg 1, Houston Texas 77204-5005 (United States); Weinstein, Roy [Texas Center for Superconductivity and Physics Department, University of Houston, 632 Science and Research Bldg 1, Houston Texas 77204-5005 (United States); Obot, Victor [Department of Mathematics, Texas Southern University, 3100 Cleburne St, Houston Texas 77004-4597 (United States); Parks, Drew [Texas Center for Superconductivity and Physics Department, University of Houston, 632 Science and Research Bldg 1, Houston Texas 77204-5005 (United States); Gandini, Alberto [Texas Center for Superconductivity and Physics Department, University of Houston, 632 Science and Research Bldg 1, Houston Texas 77204-5005 (United States); Skorpenske, Harley [Texas Center for Superconductivity and Physics Department, University of Houston, 632 Science and Research Bldg 1, Houston Texas 77204-5005 (United States)

2006-06-01

Although pinning centers created by irradiation presently produce the highest J{sub c}, it is probable that ultimately these will be emulated by chemical pinning centers. The best pinning centers produced by irradiation nevertheless provide guidelines for desirable morphology of chemical pinning structures. The highest J{sub c} produced earlier in textured HTS was obtained using isotropic high-energy ions produced by fission of {sup 235}U. This so-called U/n process produces pinning centers of diameter {<=} 4.5 nm, with an effective length of {approx}2.7 {mu}m. Maximum J{sub c} occurs for pinning center density of {approx}10{sup 10} cm{sup -3}. We use this as a model for desired chemical pinning centers. Our approach to introducing chemical pinning centers has been to produce precipitates within the HTS containing elements not native to the HTS, and to seek needlelike (columnar) deposits of small diameter. We report here on the formation of needlelike or columnar deposits in textured Y123 containing a dopant foreign to Y123. It serves as a demonstration that self-assembling nanometer diameter columns utilizing a dopant foreign to the HTS system are a feasible goal. These deposits, however, do not fully meet the ultimate requirements of pinning centers because the desired deposits should be smaller. The self-assembling columns formed contain titanium, are {approx}500 nm in diameter, and up to 10 {mu}m long. The size and morphology of the deposits vary with the mass of admixed Ti dopant. J{sub c} is decreased for small dopant mass. At larger dopant masses needlelike precipitates form, and J{sub c} increases again. A small range of mass of admixed Ti exists in which J{sub c} is enhanced by pinning. In the range of admixed Ti mass studied in these experiments there is a negligible effect on T{sub c}. Magnetization studies of J{sub c} are also reported.

Diameter Control and Photoluminescence of ZnO Nanorods from Trialkylamines

Directory of Open Access Journals (Sweden)

Tamar Andelman

2007-01-01

Full Text Available A novel solution method to control the diameter of ZnO nanorods is reported. Small diameter (2-3 nm nanorods were synthesized from trihexylamine, and large diameter (50–80 nm nanorods were synthesized by increasing the alkyl chain length to tridodecylamine. The defect (green emission of the photoluminescence (PL spectra of the nanorods varies with diameter, and can thus be controlled by the diameter control. The small ZnO nanorods have strong green emission, while the large diameter nanorods exhibit a remarkably suppressed green band. We show that this observation supports surface oxygen vacancies as the defect that gives rise to the green emission.

Effect of Tube Diameter on The Design of Heat Exchanger in Solar Drying system

Science.gov (United States)

Husham Abdulmalek, Shaymaa; Khalaji Assadi, Morteza; Al-Kayiem, Hussain H.; Gitan, Ali Ahmed

2018-03-01

The drying of agriculture product consumes a huge fossil fuel rates that demand to find an alternative source of sustainable environmental friendly energy such as solar energy. This work presents the difference between using solar heat source and electrical heater in terms of design aspect. A circular-finned tube bank heat exchanger is considered against an electrical heater used as a heat generator to regenerate silica gel in solar assisted desiccant drying system. The impact of tube diameter on the heat transfer area was investigated for both the heat exchanger and the electrical heater. The fin performance was investigated by determining fin effectiveness and fin efficiency. A mathematical model was developed using MATLAB to describe the forced convection heat transfer between hot water supplied by evacuated solar collector with 70 °C and ambient air flow over heat exchanger finned tubes. The results revealed that the increasing of tube diameter augments the heat transfer area of both heat exchanger and electrical heater. The highest of fin efficiency was around 0.745 and the lowest was around 0.687 while the fin effectiveness was found to be around 0.998.

Performance evaluation of an air-breathing high-temperature proton exchange membrane fuel cell

International Nuclear Information System (INIS)

Wu, Qixing; Li, Haiyang; Yuan, Wenxiang; Luo, Zhongkuan; Wang, Fang; Sun, Hongyuan; Zhao, Xuxin; Fu, Huide

2015-01-01

Highlights: • An air-breathing HT-PEMFC was designed and evaluated experimentally. • The peak power density of the air-breathing HT-PEMFC was 220.5 mW cm"−"2 at 200 °C. • Break-in behavior and effects of temperature and anodic stoichiometry were studied. • The effect of cell orientations on the performance was investigated. • The degradation rate of the air-breathing HT-PEMFC was around 58.32 μV h"−"1. - Abstract: The air-breathing proton exchange membrane fuel cell (PEMFC) is of great interest in mobile power sources because of its simple system design and low parasitic power consumption. Different from previous low-temperature air-breathing PEMFCs, a high-temperature PEMFC with a phosphoric acid doped polybenzimidazole (PBI) membrane as the polymer electrolyte is designed and investigated under air-breathing conditions. The preliminary results show that a peak power density of 220.5 mW cm"−"2 at 200 °C can be achieved without employing any water managements, which is comparable to those with conventional Nafion® membranes operated at low temperatures. In addition, it is found that with the present cell design, the limiting current density arising from the oxygen transfer limitation is around 700 mA cm"−"2 even at 200 °C. The short-term durability test at 200 mA cm"−"2 and 180 °C reveals that all the cells exhibit a gradual decrease in the voltage along with a rise in the internal resistance. The degradation rate of continuous operation is around 58.32 μV h"−"1, which is much smaller than those of start/stop cycling operations.

Air quality and passenger comfort in an air-conditioned bus micro-environment.

Science.gov (United States)

Zhu, Xiaoxuan; Lei, Li; Wang, Xingshen; Zhang, Yinghui

2018-04-12

In this study, passenger comfort and the air pollution status of the micro-environmental conditions in an air-conditioned bus were investigated through questionnaires, field measurements, and a numerical simulation. As a subjective analysis, passengers' perceptions of indoor environmental quality and comfort levels were determined from questionnaires. As an objective analysis, a numerical simulation was conducted using a discrete phase model to determine the diffusion and distribution of pollutants, including particulate matter with a diameter air quality and dissatisfactory thermal comfort conditions in Jinan's air-conditioned bus system. To solve these problems, three scenarios (schemes A, B, C) were designed to alter the ventilation parameters. According to the results of an improved simulation of these scenarios, reducing or adding air outputs would shorten the time taken to reach steady-state conditions and weaken the airflow or lower the temperature in the cabin. The airflow pathway was closely related to the layout of the air conditioning. Scheme B lowered the temperature by 0.4 K and reduced the airflow by 0.01 m/s, while scheme C reduced the volume concentration of PM 10 to 150 μg/m 3 . Changing the air supply angle could further improve the airflow and reduce the concentration of PM 10 . With regard to the perception of airflow and thermal comfort, the scheme with an airflow provided by a 60° nozzle was considered better, and the concentration of PM 10 was reduced to 130 μg/m 3 .

Inferring diameters of spheres and cylinders using interstitial water.

Science.gov (United States)

Herrera, Sheryl L; Mercredi, Morgan E; Buist, Richard; Martin, Melanie

2018-06-04

Most early methods to infer axon diameter distributions using magnetic resonance imaging (MRI) used single diffusion encoding sequences such as pulsed gradient spin echo (SE) and are thus sensitive to axons of diameters > 5 μm. We previously simulated oscillating gradient (OG) SE sequences for diffusion spectroscopy to study smaller axons including the majority constituting cortical connections. That study suggested the model of constant extra-axonal diffusion breaks down at OG accessible frequencies. In this study we present data from phantoms to test a time-varying interstitial apparent diffusion coefficient. Diffusion spectra were measured in four samples from water packed around beads of diameters 3, 6 and 10 μm; and 151 μm diameter tubes. Surface-to-volume ratios, and diameters were inferred. The bead pore radii estimates were 0.60±0.08 μm, 0.54±0.06 μm and 1.0±0.1 μm corresponding to bead diameters ranging from 2.9±0.4 μm to 5.3±0.7 μm, 2.6±0.3 μm to 4.8±0.6 μm, and 4.9±0.7 μm to 9±1 μm. The tube surface-to-volume ratio estimate was 0.06±0.02 μm -1 corresponding to a tube diameter of 180±70 μm. Interstitial models with OG inferred 3-10 μm bead diameters from 0.54±0.06 μm to 1.0±0.1 μm pore radii and 151 μm tube diameters from 0.06±0.02 μm -1 surface-to-volume ratios.

Enteroclysis in adult celiac disease: assessment of jejuno-ileal diameter and of number of folds

International Nuclear Information System (INIS)

La Seta, F.; Bucellato, A.; Cabibbo, L.; Cottone, M.; Salerno, G.; Dardanoni, G.

1991-01-01

The authors retrospectively reviewed the radiographic findings (obtained with double-contrast small bowel enema) of 27 patients with adult celiac disease and of 27 healthy control subjects. Two parameters were measurated in two different locations; lumen diameter and number of folds both in proximal jejunum and in the distal ileum. Statistical differences in mean values between cases and controls were calculated, and correlations between the four variables were assessed. Sensitivity, specificity and their 95% confidence limits were calculated for all the variables. The best parameter in discriminating cases from controls seems to be the caliber of distal ileum (>3 cm), with 93% sensitivity and 100% specificity. The value of the obtained results is discussed

Vertical pneumatic conveying in dilute and dense-phase flows: experimental study of the influence of particle density and diameter on fluid dynamic behavior

Directory of Open Access Journals (Sweden)

Narimatsu C.P.

2001-01-01

Full Text Available In this work, the effects of particle size and density on the fluid dynamic behavior of vertical gas-solid transport of Group D particles in a 53.4 mm diameter transport tube were studied. For the conditions tested, the experimental curves of pressure gradient versus air velocity presented a minimum pressure gradient point, which is associated with a change in the flow regime from dense to dilute phase. The increases in particle size from 1.00 to 3.68 mm and in density from 935 to 2500 kg/m³ caused an increase in pressure gradient for the dense-phase transport region, but were not relevant in dilute transport. The transition velocity between dense and dilute flow (Umin also increased with increasing particle density and diameter. An empirical equation was fitted for predicting transition air velocity for the transport of glass spheres. Additional experiments, covering a wider range of conditions and particles properties, are still needed to allow the fitting of a generalized equation for prediction of Umin.

A statistical evaluation of asbestos air concentrations

International Nuclear Information System (INIS)

Lange, J.H.

1999-01-01

Both area and personal air samples collected during an asbestos abatement project were matched and statistically analysed. Among the many parameters studied were fibre concentrations and their variability. Mean values for area and personal samples were 0.005 and 0.024 f cm - - 3 of air, respectively. Summary values for area and personal samples suggest that exposures are low with no single exposure value exceeding the current OSHA TWA value of 0.1 f cm -3 of air. Within- and between-worker analysis suggests that these data are homogeneous. Comparison of within- and between-worker values suggests that the exposure source and variability for abatement are more related to the process than individual practices. This supports the importance of control measures for abatement. Study results also suggest that area and personal samples are not statistically related, that is, there is no association observed for these two sampling methods when data are analysed by correlation or regression analysis. Personal samples were statistically higher in concentration than area samples. Area sampling cannot be used as a surrogate exposure for asbestos abatement workers. (author)

Air conditioning device for reactor buildings

International Nuclear Information System (INIS)

Kikuchi, Shiro.

1982-01-01

Purpose: To decrease the opening areas of pipe lines for an air conditioning device at the portions passing through the shielding walls of a reactor building for a FBR type reactor, as well as reduce the size of the building. Constitution: Airs in the building for containing reactor are liquefied in an air liquefying mechanism. The liquefied airs are sent by way of pipe lines to each of evaporators, wherein each of the chambers are cooled because of latent heat of evaporation and evaporated airs are released to each of the chambers. The airs released to each of the chambers are collected into an exhaust chamber and sent by way of a duct to the air liquefying mechanism and liquefied again. Since the volume of the liquefied airs may be smaller than the amount conventionally required for usual cooled airs, the pipe lines passing through the shielding walls of the building can be of smaller diameter. This can decrease the opening areas of the pipe lines at the portions passing through the walls of the shieldings and, since the opening areas are smaller, the structure of the radiation shieldings can be simplified in these portions. Further, since the space of the pipe lines in the building is reduced extremely, the size of the building can be reduced. (Moriyama, K.)

Measuring Electrospun Nanofibre Diameter: a Novel Approach

International Nuclear Information System (INIS)

Ziabari, M.; Mottaghitalab, V.; Haghi, A. K.; McGovern, S. T.

2008-01-01

A new method based on image analysis for electrospun nanofibre diameter measurement is presented. First, the SEM micrograph of the nanofibre web obtained by electrospinning process is converted to binary image using local thresholding method. In the next step, skeleton and distance transformed image are generated. Then, the intersection points which bring about untrue measurements are identified and removed from the skeleton. Finally, the resulting skeleton and distance transformed image are used to determine fibre diameter. The method is evaluated by a simulated image with known characteristics generated by ?-randomness procedure. The results indicate that this approach is successful in making fast, accurate automated measurements of electrospun fibre diameters. (cross-disciplinary physics and related areas of science and technology)

2-cm versus 4-cm surgical excision margins for primary cutaneous melanoma thicker than 2 mm: a randomised, multicentre trial

DEFF Research Database (Denmark)

Gillgren, Peter; Drzewiecki, Krzysztof T; Niin, Marianne

2011-01-01

Optimum surgical resection margins for patients with clinical stage IIA-C cutaneous melanoma thicker than 2 mm are controversial. The aim of the study was to test whether survival was different for a wide local excision margin of 2 cm compared with a 4-cm excision margin.......Optimum surgical resection margins for patients with clinical stage IIA-C cutaneous melanoma thicker than 2 mm are controversial. The aim of the study was to test whether survival was different for a wide local excision margin of 2 cm compared with a 4-cm excision margin....

Determination of gamma emitting radionuclides in environmental air and precipitation samples with a Ge(Li) detector

International Nuclear Information System (INIS)

Hoetzl, H.; Rosner, G.; Winkler, R.; Sansoni, B.

1977-01-01

The concentrations of the radionuclides 7 Be, 54 Mn, 95 Zr, 95 Nb, 103 Ru, 106 Ru, 125 Sb, 137 Cs, 140 Ba/ 140 La, 141 Ce and 144 Ce in ground level air and of 7 Be, 95 Zr, 137 Cs and 144 Ce in precipitation were determined since 1970 and 1971 respectively at Neuherberg, 10 km north of Munich, by gamma spectrometry using a 60 cm 3 Ge(Li) detector. Dust samples were collected twice a month 1 m above ground from about 40,000 m 3 of air on 46 cm x 28 cm microsorbane filters and pressed to small cylinders of 35 cm 3 in size. Sensitivity of the procedure is of the order of 1 fCi/m 3 for air and of 10 pCi/m 2 per month for precipitation samples at a counting time of 1500 min. (author)

PERENCANAAN SISTEM PENYALURAN AIR LIMBAH DOMESTIK KOTA BOGOR MENGGUNAKAN AIR HUJAN UNTUK DEBIT PENGGELONTORAN (Planning of Domestic Wastewater Sewerage in Bogor City Using Rainwater for Flushing Flowrate

Directory of Open Access Journals (Sweden)

Allen Kurniawan

2015-03-01

Full Text Available ABSTRAK Sistem penyaluran air limbah merupakan bagian penting dalam sistem prasarana perkotaan. Tujuan penelitian ini merancang konfigurasi sistem penyaluran air limbah domestik dan memodifikasi sistem drainase skala mikro di Kota Bogor untuk memenuhi debit penggelontoran. Data penelitian berupa data sekunder dari instansi terkait, studi pustaka, dan hasil beberapa penelitian terdahulu. Perkiraan jumlah penduduk setiap kelurahan pada tahun perencanaan 2035 menggunakan metode geometrik. Instalasi Pengolahan Air Limbah (IPAL dibangun pada dua lokasi yaitu IPAL 1 di Kelurahan Bantarjati dan IPAL 2 di Kelurahan Mekarwangi. Perencanaan blok pelayanan sebanyak 254 buah dan jumlah manhole sebanyak 334 buah. Perhitungan kebutuhan air bersih menghasilkan nilai debit jam puncak air limbah (Qjp rata-rata sebesar 5,75 L/detik. Debit air bersih menghasilkan perkiraan sebesar 80% air limbah. Nilai Qp pada inlet IPAL 1 sebesar 0,59 m3/detik dengan diameter 900 mm, sedangkan nilai Qp pada inlet IPAL 2 sebesar 1,42 m3/detik dengan diameter 1000 mm. Pengaliran air limbah diusahakan secara gravitasi dengan kedalaman galian maksimum sebesar 6 m. Sistem drainase skala mikro dirancang untuk memenuhi debit penggelontoran. Perhitungan intensitas hujan terpilih menggunakan Metode Sherman. Titik penggelontoran sebanyak 53 titik dengan debit penggelontoran rata-rata sebesar 0,03 m3/detik. Debit saluran drainase rata-rata sebesar 0,25 m3/detik. ABSTRACT Sewerage system is an important part of the urban infrastructure. The research objectives were to design a system configuration domestic wastewater sewerage and modify drainage systems in Bogor City for flushing discharge. The research used secondary data from relevant institutions, literature, and the results of previous researches. Estimated of the population of each village in 2035 used geometric method. Wastewater Treatment Plant (WWTP would be constructed in two locations in Bantarjati and Mekarwangi Village. Planning

The distribution of air bubble size in the pneumo-mechanical flotation machine . Rozkład wielkości pęcherzyków powietrza w pneumo-mechanicznej maszynie flotacyjnej

Science.gov (United States)

Brożek, Marian; Młynarczykowska, Anna

2012-12-01

The flotation rate constant is the value characterizing the kinetics of cyclic flotation. In the statistical theory of flotation its value is the function of probabilities of collision, adhesion and detachment of particle from the air bubble. The particle - air bubble collision plays a key role since there must be a prior collision before the particle - air bubble adhesion happens. The probability of such an event to occur is proportional to the ratio of the particle diameter to the bubble diameter. When the particle size is given, it is possible to control the value of collision probability by means of the size of air bubble. Consequently, it is significant to find the effect of physical and physicochemical factors upon the diameter of air bubbles in the form of a mathematical dependence. In the pneumo-mechanical flotation machine the air bubbles are generated by the blades of the rotor. The dispergation rate is affected by, among others, rotational speed of the rotor, the air flow rate and the liquid surface tension, depending on the type and concentration of applied flotation reagents. In the proposed paper the authors will present the distribution of air bubble diameters on the grounds of the above factors, according to the laws of thermodynamics. The correctness of the derived dependences will be verified empirically.

Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

Energy Technology Data Exchange (ETDEWEB)

Mercado-Pagán, Ángel E.; Kang, Yunqing [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Findlay, Michael W. [Department of Plastic and Reconstructive Surgery, Stanford University, Stanford, CA (United States); University of Melbourne Department of Surgery, Royal Melbourne Hospital, Parkville, VIC (Australia); Yang, Yunzhi, E-mail: ypyang@stanford.edu [Department of Orthopedic Surgery, Stanford University, Stanford, CA (United States); Department of Materials Science and Engineering, Stanford University, Stanford, CA (United States)

2015-04-01

Engineering of small diameter (< 6 mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5 × 10{sup −6} cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. - Highlights: • Hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties could be tailored through adjustments to fabrication parameters. • Properties could match or exceed those of blood vessels. • HFM showed excellent compatibility in vitro. • HFMs have the potential to be used for small diameter vascular grafts.

Development and evaluation of elastomeric hollow fiber membranes as small diameter vascular graft substitutes

International Nuclear Information System (INIS)

Mercado-Pagán, Ángel E.; Kang, Yunqing; Findlay, Michael W.; Yang, Yunzhi

2015-01-01

Engineering of small diameter (< 6 mm) vascular grafts (SDVGs) for clinical use remains a significant challenge. Here, elastomeric polyester urethane (PEU)-based hollow fiber membranes (HFMs) are presented as an SDVG candidate to target the limitations of current technologies and improve tissue engineering designs. HFMs are fabricated by a simple phase inversion method. HFM dimensions are tailored through adjustments to fabrication parameters. The walls of HFMs are highly porous. The HFMs are very elastic, with moduli ranging from 1–4 MPa, strengths from 1–5 MPa, and max strains from 300–500%. Permeability of the HFMs varies from 0.5–3.5 × 10 −6 cm/s, while burst pressure varies from 25 to 35 psi. The suture retention forces of HFMs are in the range of 0.8 to 1.2 N. These properties match those of blood vessels. A slow degradation profile is observed for all HFMs, with 71 to 78% of the original mass remaining after 8 weeks, providing a suitable profile for potential cellular incorporation and tissue replacement. Both human endothelial cells and human mesenchymal stem cells proliferate well in the presence of HFMs up to 7 days. These results demonstrate a promising customizable PEU HFMs for small diameter vascular repair and tissue engineering applications. - Highlights: • Hollow fiber membranes (HFMs) were fabricated and evaluated. • HFM properties could be tailored through adjustments to fabrication parameters. • Properties could match or exceed those of blood vessels. • HFM showed excellent compatibility in vitro. • HFMs have the potential to be used for small diameter vascular grafts

Plasmonic Hotspots in Air: An Omnidirectional Three-Dimensional Platform for Stand-Off In-Air SERS Sensing of Airborne Species.

Science.gov (United States)

Phan-Quang, Gia Chuong; Lee, Hiang Kwee; Teng, Hao Wen; Koh, Charlynn Sher Lin; Yim, Barnabas Qinwei; Tan, Eddie Khay Ming; Tok, Wee Lee; Phang, In Yee; Ling, Xing Yi

2018-05-14

Molecular-level airborne sensing is critical for early prevention of disasters, diseases, and terrorism. Currently, most 2D surface-enhanced Raman spectroscopy (SERS) substrates used for air sensing have only one functional surface and exhibit poor SERS-active depth. "Aerosolized plasmonic colloidosomes" (APCs) are introduced as airborne plasmonic hotspots for direct in-air SERS measurements. APCs function as a macroscale 3D and omnidirectional plasmonic cloud that receives laser irradiation and emits signals in all directions. Importantly, it brings about an effective plasmonic hotspot in a length scale of approximately 2.3 cm, which affords 100-fold higher tolerance to laser misalignment along the z-axis compared with 2D SERS substrates. APCs exhibit an extraordinary omnidirectional property and demonstrate consistent SERS performance that is independent of the laser and analyte introductory pathway. Furthermore, the first in-air SERS detection is demonstrated in stand-off conditions at a distance of 200 cm, highlighting the applicability of 3D omnidirectional plasmonic clouds for remote airborne sensing in threatening or inaccessible areas. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Numerical investigation on effect of riser diameter and inclination on system parameters in a two-phase closed loop thermosyphon solar water heater

International Nuclear Information System (INIS)

Aung, Nay Zar; Li, Songjing

2013-01-01

Highlights: • Optimum inclination for maximum heat flux changes with latitude of location. • Optimum inclination for maximum heat flux also changes local solar time. • Maximum flow rate increases with increasing of riser tube size. • Maximum mass flow rate is obtained at different inclinations for different risers. • Length of two-phase region depends on inclination angles but not riser tube size. - Abstract: In this work, the effect of riser diameter and its inclination angle on system parameters in a two-phase closed loop thermosyphon solar water heater has been numerically investigated. Here, receivable heat flux by the collector, circulating mass flow rate, driving pressure, total pressure drop, heat transfer coefficient in risers and collector efficiency are defined as system parameters. For this aim, a model of two-phase thermosyphon solar water heater that is acceptable for various inclinations is presented and variations of riser diameter and inclination are considered. The riser tube size is varied from 1.25 cm to 2.5 cm with inclination range 2–75°. The system absolute pressure is set as 3567 Pa and water is chosen as working fluid. The results show that higher inclination angle is required for higher latitude location to obtain maximum solar heat flux. At local solar noon of 21.996 north latitude, the optimum inclination angle increases in the range of 24–44° with increasing of riser diameter giving maximum circulating mass flow rate from 0.02288 kg/s to 0.03876 kg/s. The longer two-phase heat transfer characteristics can be obtained at smaller inclination angles and mass flow rate for all riser tube sizes. Therefore, it is observed that the optimum inclination angles and diameters for solar heat flux, circulating mass flow rate and heat transfer coefficient in two-phase thermosyphon systemdo not coincide. From this work, better understanding and useful information are provided for constructing two-phase thermosyphon solar heaters

[Working ability between air and trimix breathing gas under 8 ATA air condition].

Science.gov (United States)

Shibayama, M; Kosugi, S; Mohri, M; Yamamura, I; Oda, S; Kimura, A; Takeuchi, J; Mano, Y

1990-04-01

Pneumatic caisson work in Japan has come into operation since 1924. Afterward, this technique of compressed air work has been widely utilized in the construction of foundation basements, shafts of the bottom tunnel shields for subway and so forth. While using this technique of compressed air work means that workers have to be exposed to hyperbaric environment, this technique has risks of not only decompression sickness (DCS) but also toxicity of poisonous gas and/or oxygen deficiency. However, this technique is independent of city construction work and the operation of compressed air work higher than 5ATA (4.0 kg/cm2G) is actually been planning recently. Accordingly unmanned caisson work is considered as a better technique for such higher pressurized work, even though workers must enter into hyperbaric working fields for maintenance or repair of unmanned operated machinery and materials. This research is to establish the safe work under hyperbaric air environment at 8ATA.

Catalytic growth of carbon nanotubes with large inner diameters

Directory of Open Access Journals (Sweden)

WEI REN ZHONG

2005-02-01

Full Text Available Carbon nanotubes (2.4 g/g catalyst, with large inner diameters were successfully synthesized through pyrolysis of methane on a Ni–Cu–Al catalyst by adding sodium carbonate into the carbon nanotubes growth system. The inner diameter of the carbon nanotubes prepared by this method is about 20–60 nm, while their outer diameter is about 40–80 nm. Transmission electron microscopy and X-ray diffraction were employed to investigate the morphology and microstructures of the carbon nanotubes. The analyses showed that these carbon nanotubes have large inner diameters and good graphitization. The addition of sodium carbonate into the reaction system brings about a slight decrease in the methane conversion and the yield of carbon. The experimental results showed that sodium carbonate is a mildly toxic material which influenced the catalytic activity of the Ni–Cu–Al catalyst and resulted in the formation of carbon nanotubes with large inner diameters. The growth mechanism of the carbon nanotubes with large inner diameters is discussed in this paper.

Detonation cell size measurements in high-temperature hydrogen-air-steam mixtures at the BNL high-temperature combustion facility

International Nuclear Information System (INIS)

Ciccarelli, G.; Ginsberg, T.; Boccio, J.L.

1997-11-01

The High-Temperature Combustion Facility (HTCF) was designed and constructed with the objective of studying detonation phenomena in mixtures of hydrogen-air-steam at initially high temperatures. The central element of the HTCF is a 27-cm inner-diameter, 21.3-m long cylindrical test vessel capable of being heating to 700K ± 14K. A unique feature of the HTCF is the 'diaphragmless' acetylene-oxygen gas driver which is used to initiate the detonation in the test gas. Cell size measurements have shown that for any hydrogen-air-steam mixture, increasing the initial mixture temperature, in the range of 300K to 650K, while maintaining the initial pressure of 0.1 MPa, decreases the cell size and thus makes the mixture more detonable. The effect of steam dilution on cell size was tested in stoichiometric and off-stoichiometric (e.g., equivalence ratio of 0.5) hydrogen-air mixtures. Increasing the steam dilution in hydrogen-air mixtures at 0.1 MPa initial pressure increases the cell size, irrespective of initial temperature. It is also observed that the desensitizing effect of steam diminished with increased initial temperature. A 1-dimensional, steady-state Zel'dovich, von Neumann, Doring (ZND) model, with full chemical kinetics, has been used to predict cell size for hydrogen-air-steam mixtures at different initial conditions. Qualitatively the model predicts the overall trends observed in the measured cell size versus mixture composition and initial temperature and pressure. It was found that the proportionality constant used to predict detonation cell size from the calculated ZND model reaction zone varies between 10 and 100 depending on the mixture composition and initial temperature. 32 refs., 35 figs

GUIDE TO CALCULATING TRANSPORT EFFICIENCY OF AEROSOLS IN OCCUPATIONAL AIR SAMPLING SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Hogue, M.; Hadlock, D.; Thompson, M.; Farfan, E.

2013-11-12

This report will present hand calculations for transport efficiency based on aspiration efficiency and particle deposition losses. Because the hand calculations become long and tedious, especially for lognormal distributions of aerosols, an R script (R 2011) will be provided for each element examined. Calculations are provided for the most common elements in a remote air sampling system, including a thin-walled probe in ambient air, straight tubing, bends and a sample housing. One popular alternative approach would be to put such calculations in a spreadsheet, a thorough version of which is shared by Paul Baron via the Aerocalc spreadsheet (Baron 2012). To provide greater transparency and to avoid common spreadsheet vulnerabilities to errors (Burns 2012), this report uses R. The particle size is based on the concept of activity median aerodynamic diameter (AMAD). The AMAD is a particle size in an aerosol where fifty percent of the activity in the aerosol is associated with particles of aerodynamic diameter greater than the AMAD. This concept allows for the simplification of transport efficiency calculations where all particles are treated as spheres with the density of water (1g cm-3). In reality, particle densities depend on the actual material involved. Particle geometries can be very complicated. Dynamic shape factors are provided by Hinds (Hinds 1999). Some example factors are: 1.00 for a sphere, 1.08 for a cube, 1.68 for a long cylinder (10 times as long as it is wide), 1.05 to 1.11 for bituminous coal, 1.57 for sand and 1.88 for talc. Revision 1 is made to correct an error in the original version of this report. The particle distributions are based on activity weighting of particles rather than based on the number of particles of each size. Therefore, the mass correction made in the original version is removed from the text and the calculations. Results affected by the change are updated.

Dose optimization in pelvic radiography by air gap method on CR and DR systems – A phantom study

International Nuclear Information System (INIS)

Chan, C.T.P.; Fung, K.K.L.

2015-01-01

Objectives: This study aimed at investigating the feasibility of replacing the anti-scatter grid with an air gap at a pelvic radiographic examination in order to reduce patient dose while retaining diagnostic image quality. Methods: An anthropomorphic pelvis phantom was placed on a device that allowed the adjustment of different air gap thicknesses introduced between the phantom and the image receptor of Computed Radiography (CR) and Digital Radiography (DR) systems. Grid and non-grid images with different air gap thicknesses of both systems were produced. Ovary and testes doses were measured using thermoluminescent dosimeters. Radiographic quality of all images was rated by 5 experienced radiographers blindly using the Image Quality Score (IQS) and Visual Grading Analysis (VGA) systems. Results: Images of diagnostic quality were produced while the grid was replaced by a range of 0–25 cm air gap thickness in the pelvic radiographic examination. At non-grid examination with 10 cm air gap thickness, a maximum of relative dose reduction by 70.7% and 81.6% at CR; 68.6% and 79.4% at DR were achieved respectively at ovary and testes locations of the phantom as compared with their corresponding grid examinations. Conclusion: 10 cm was found to be the optimal air gap thickness at the tested pelvic examination. Effective dose was found to be reduced by 2 and 2.3 times respectively at the CR and DR examinations while the anti-scatter grid was replaced by 10 cm air gap. However, dose reduction effect by air gap method was found to be more pronounced in CR than in DR. - Highlights: • 10 cm air gap was found to be a substitute to replace grid in pelvic RANDO in CR/DR. • Over 68.6% of dose reduction effect were achieved at the ovary and testes regions. • Over 76.4% of reduction in effective dose were achieved at both the tested regions. • Dose reduction by air gap method was found to be more pronounced in CR than in DR

On the diameter of dot-critical graphs

Directory of Open Access Journals (Sweden)

Doost Ali Mojdeh

2009-01-01

Full Text Available A graph G is \\(k\\-dot-critical (totaly \\(k\\-dot-critical if \\(G\\ is dot-critical (totaly dot-critical and the domination number is \\(k\\. In the paper [T. Burtona, D. P. Sumner, Domination dot-critical graphs, Discrete Math, 306 (2006, 11-18] the following question is posed: What are the best bounds for the diameter of a \\(k\\-dot-critical graph and a totally \\(k\\-dot-critical graph \\(G\\ with no critical vertices for \\(k \\geq 4\\? We find the best bound for the diameter of a \\(k\\-dot-critical graph, where \\(k \\in\\{4,5,6\\}\\ and we give a family of \\(k\\-dot-critical graphs (with no critical vertices with sharp diameter \\(2k-3\\ for even \\(k \\geq 4\\.

On the performance of small diameter gas cyclones

International Nuclear Information System (INIS)

Halasz, Marcos Roberto Teixeira

2002-02-01

Small diameter cyclones represent a potential alternative for the removal of small diameter particles from gaseous mixtures as well as the environmental control of their emission. In order to establish feasible configurations of a small diameter cyclone applied in the separation of solid particles dispersed in a gas and considering a large quantify of experimental data in literature, neural networks were used to estimate the equipment grade efficiency and pressure drop. In order to evaluate a performance of many small diameters configurations and analysis was carried of parametrical sensibility which determines the most important variables on separation efficiency determination. A set of experimental runs was carried out in a lab-scale mini-cyclone in order to obtain the separation efficiency and pressure drop for different configurations, and evaluate the feasibility of coupling a post-cyclone device to improve the equipment overall performance. The cyclones used presented diameters of 0.03 and 0.05 m and the remaining dimensions varied proportionally about those found in Stairmand high-efficiency cyclones. Experimental separation efficiencies up to 99% were obtained in this work. These results confirm the feasibility of the experimental set-up configuration proposed. (author)

Oxygen isotope systematics of chondrules in the Murchison CM2 chondrite and implications for the CO-CM relationship

Science.gov (United States)

Chaumard, Noël; Defouilloy, Céline; Kita, Noriko T.

2018-05-01

High-precision oxygen three-isotope measurements of olivine and pyroxene were performed on 29 chondrules in the Murchison CM2 chondrite by secondary ion mass spectrometry (SIMS). The oxygen isotope ratios of analyzed chondrules all plot very close to the primitive chondrule minerals (PCM) line. In each of 24 chondrules, the olivine and/or pyroxene grains analyzed show indistinguishable oxygen isotope ratios. Exceptions are minor occurrences of isotopically distinguished relict olivine grains, which were found in nine chondrules. The isotope homogeneity of these phenocrysts is consistent with a co-magmatic crystallization of olivine and pyroxene from the final chondrule melts and a significant oxygen isotope exchange between the ambient gas and the melts. Homogeneous type I chondrules with Mg#'s of 98.9-99.5 have host chondrule Δ17O values ranging from -6.0‰ to -4.1‰, with one exception (Δ17O: -1.2‰; Mg#: 99.6). Homogeneous chondrules with Mg#'s poor H2O ice (∼0.3-0.4× the CI dust; Δ17O > 0‰) and at dust enrichments of ∼300-2000×. Regarding the Mg# and oxygen isotope ratios, the chondrule populations sampled by CM and CO chondrites are similar and indistinguishable. The similarity of these 16O-rich components in CO and CM chondrites is also supported by the common Fe/Mn ratio of olivine in type II chondrules. Although they accreted similar high-temperature silicates, CO chondrites are anhydrous compared to CM chondrites, suggesting they derived from different parent bodies formed inside and outside the snow line, respectively. If chondrules in CO and CM chondrites formed at the same disk locations but the CM parent body accreted later than the CO parent body, the snow line might have crossed the common chondrule-forming region towards the Sun between the time of the CO and CM parent bodies accretion.

Slug Flow Analysis in Vertical Large Diameter Pipes

Science.gov (United States)

Roullier, David

The existence of slug flow in vertical co-current two-phase flow is studied experimentally and theoretically. The existence of slug flow in vertical direction implies the presence of Taylor bubbles separated by hydraulically sealed liquid slugs. Previous experimental studies such as Ombere-Ayari and Azzopardi (2007) showed the evidence of the non-existence of Taylor bubbles for extensive experimental conditions. Models developed to predict experimental behavior [Kocamustafaogullari et al. (1984), Jayanti and Hewitt. (1990) and Kjoolas et al. (2017)] suggest that Taylor bubbles may disappear at large diameters and high velocities. A 73-ft tall and 101.6-mm internal diameter test facility was used to conduct the experiments allowing holdup and pressure drop measurements at large L/D. Superficial liquid and gas velocities varied from 0.05-m/s to 0.2 m/s and 0.07 m/s to 7.5 m/s, respectively. Test section pressure varied from 38 psia to 84 psia. Gas compressibility effect was greatly reduced at 84 psia. The experimental program allowed to observe the flow patterns for flowing conditions near critical conditions predicted by previous models (air-water, 1016 mm ID, low mixture velocities). Flow patterns were observed in detail using wire-mesh sensor measurements. Slug-flow was observed for a narrow range of experimental conditions at low velocities. Churn-slug and churn-annular flows were observed for most of the experimental data-points. Cap-bubble flow was observed instead of bubbly flow at low vSg. Wire-mesh measurements showed that the liquid has a tendency to remain near to the walls. The standard deviation of radial holdup profile correlates to the flow pattern observed. For churn-slug flow, the profile is convex with a single maximum near the pipe center while it exhibits a concave shape with two symmetric maxima close to the wall for churn-annular flow. The translational velocity was measured by two consecutive wire-mesh sensor crosscorrelation. The results show

90-year-old firn air from Styx glacier, East Antarctica

Science.gov (United States)

Jang, Y.; Ahn, J.; Buizert, C.; Lee, H. G.; Hong, S.; Han, Y.; Jun, S. J.; Hur, S. D.

2017-12-01

Firn is the upper part of the glacier that has not yet been completely changed to the ice. In this layer, firn air can move through the open pores and be pumped for sampling. We obtained firn air and ice cores from Styx glacier (73°51'95″ S, 163°41'217″ E, 1623m asl.), East Antarctica during 2014-2015. The Styx glacier is located near coast, and has an accumulation rate of 0.13 Mgm-2y-1 with a mean annual temperature of -31.7 °. We found that the lock-in depth (depth where gas diffusion starts to stop, "LID") is 52.4 m and bubble close-off depth (the depth to the snow-ice transition perfectly, "COD") is 65.1 m. Therefore lock-in zone (between LID and COD, "LIZ") is 52.4 - 65.1 m. Concentrations of greenhouse gases (CO2, CH4, n=13) in the firn air were analyzed at US National Oceanic and Atmospheric Administration (NOAA) and 15N of N2 was measured at the Scripps Institution of Oceanography (SIO). We find that the firn air ages are up to about 90 years, the oldest firn air ages observed among coastal glaciers. In order to better understand physical properties and chemical composition, methane concentration and total air content of the closed bubbles in the LIZ (3 cm resolution, n=124) were analyzed by a wet extraction method at Seoul National University. The CH4 concentration and total air content show large variations in cm-scale depth intervals, and they are anti-correlated with each other. The CH4 concentration changes in a few cm corresponds to up to 40 years in CH4 age. We also applied Centre for Ice and Climate (CIC) 1-dimensional diffusion model and simulated greenhouse gas concentration profiles to quantitatively understand how the air moves in the Styx firn column. We hypothesize that density variations in the firn may increase thickness of LIZ and consequently increase of firn gas ages.

Design of an ionization diffusion chamber detector

International Nuclear Information System (INIS)

Sugiarto, S.

1976-01-01

Prototype of an Ionization Diffusion Chamber detector has been made. It is a silindrical glass, 20 cm in diameter, 13,5 cm in height, air gas filled, operated at room pressure and room temperature at the top of this instrument while for the box temperature dry ice (CO 2 solid) temperature is used. This detector is ready for seeing alpha and beta particle tracks. (author)

The value of radiochromic film dosimetry around air cavities: experimental results and Monte Carlo simulations

International Nuclear Information System (INIS)

Paelinck, L; Reynaert, N; Thierens, H; Wagter, C de; Neve, W de

2003-01-01

In this study we investigate radiochromic film dosimetry around air cavities with particular focus on the perturbation of the dose distribution by the film when the film is parallel to the beam axis. We considered a layered polystyrene phantom containing an air cavity as a model for the air-soft tissue geometry that may occur after surgical resection of a paranasal sinus tumour. A radiochromic film type MD-55 was positioned within the phantom so that it intersected the cavity. Two phantom set-ups were examined. In the first case, the air cavity is at the centre of the phantom, thus the film is lying along the central beam axis. In the second case, the cavity and film are located 2 cm offset from the phantom centre and the central beam axis. In order to examine the influence of the film on the dose distribution and to interpret the film-measured results, Monte Carlo simulations were performed. The film was modelled rigorously to incorporate the composition and structure of the film. Two field configurations, a 1 x 10 cm 2 field and a 10 x 10 cm 2 field, were examined. The dose behind the air cavity is reduced by 6 to 7% for both field configurations when a film that intersects the cavity contains the central beam axis. This is due to the attenuation exerted by the film when photons cross the cavity. Offsetting the beam to the cavity and the film by 2 cm removes the dose reduction behind the air cavity completely. Another result was that the rebuild-up behind the cavity for the 10 x 10 cm 2 field, albeit less significant than for the 1 x 10 cm 2 field, could only be measured by the film that was placed offset with respect to the central beam axis. Although radiochromic film is approximately soft-tissue equivalent and energy independent as compared to radiographic films, care should be taken in the case of inhomogeneous phantoms when the film intersects air cavities and contains the beam central axis. Errors in dose measurement can be expected distal to the air cavity

Diameter dependent electron transfer kinetics in semiconductor-enzyme complexes.

Science.gov (United States)

Brown, Katherine A; Song, Qing; Mulder, David W; King, Paul W

2014-10-28

Excited state electron transfer (ET) is a fundamental step for the catalytic conversion of solar energy into chemical energy. To understand the properties controlling ET between photoexcited nanoparticles and catalysts, the ET kinetics were measured for solution-phase complexes of CdTe quantum dots and Clostridium acetobutylicum [FeFe]-hydrogenase I (CaI) using time-resolved photoluminescence spectroscopy. Over a 2.0-3.5 nm diameter range of CdTe nanoparticles, the observed ET rate (kET) was sensitive to CaI concentration. To account for diameter effects on CaI binding, a Langmuir isotherm and two geometric binding models were created to estimate maximal CaI affinities and coverages at saturating concentrations. Normalizing the ET kinetics to CaI surface coverage for each CdTe diameter led to k(ET) values that were insensitive to diameter, despite a decrease in the free energy for photoexcited ET (ΔGET) with increasing diameter. The turnover frequency (TOF) of CaI in CdTe-CaI complexes was measured at several molar ratios. Normalization for diameter-dependent changes in CaI coverage showed an increase in TOF with diameter. These results suggest that k(ET) and H2 production for CdTe-CaI complexes are not strictly controlled by ΔG(ET) and that other factors must be considered.

Effects of ejector geometries on performance of ejector-expansion R410A air conditioner considering cooling seasonal performance factor

International Nuclear Information System (INIS)

Jeon, Yongseok; Jung, Jongho; Kim, Dongwoo; Kim, Sunjae; Kim, Yongchan

2017-01-01

Highlights: •The performance of an ejector-expansion R410A air conditioner is measured. •The effect of ejector geometries on the COP and CSPF is analyzed. •The mixing-section diameter of the ejector is optimized based on the CSPF. •The mixing-section diameter is optimized based on the climatic conditions. -- Abstract: The objective of this study was to investigate the effects of ejector geometries on the performance of an ejector-expansion air conditioner (EEAC) considering the cooling seasonal performance factor (CSPF). The performance of the EEAC using R410A was measured and analyzed by varying the compressor speed, outdoor-bin temperature, operating pressures, nozzle-throat diameter, and mixing-section diameter. The EEAC in the medium-capacity mode exhibited maximum coefficient of performance (COP) improvement, i.e., 7.5%, over the baseline (conventional) cycle. The optimum mixing-section diameter was determined to be 9 mm based on the CSPF. In addition, the optimum mixing-section diameter increased with an increase in the annual average outdoor temperature. The CSPF of the EEAC with the optimized mixing-section diameter improved in the range of 16.0–20.3% over the baseline cycle depending on the climatic conditions.

Pulmonary aspergillosis in immunocompetent patients without air-meniscus sign and underlying lung disease: CT findings and histopathologic features

Energy Technology Data Exchange (ETDEWEB)

Yoon, Soon Ho; Park, Chang Min; Goo, Jin Mo; Lee, Hyun Ju (Dept. of Radiology and Institute of Radiation Medicine, Seoul National Univ. Hospital, Seoul (Korea, Republic of)), email: rosaceci@radiol.snu.ac.kr

2011-09-15

Background: Pulmonary aspergillosis in immunocompetent patients has been described as a saprophytic infection with pre-existing lung lesions showing an air-meniscus sign on chest radiograph or CT scans. There have been rare articles dealing with pulmonary aspergillosis in immunocompetent patients without pre-existing lung lesions. Purpose: To evaluate the CT findings of pulmonary aspergillosis in immunocompetent patients without air-meniscus and underlying lung disease and to correlate the CT findings and pathologic features of pulmonary aspergillosis in these patients. Material and Methods: A total of seven surgically proven pulmonary aspergillosis found in immunocompetent patients without an air-meniscus and underlying lung disease (M:F = 1:6; mean age 63.4 years) were included. On CT, the lesion shape, margin, type, location, diameter, presence of satellite nodules, presence of CT halo sign or hypodense sign, and interval growth were evaluated. Histopathologic features of each lesion were classified as one of the following; primary aspergilloma, chronic necrotizing pulmonary aspergillosis, or invasive pulmonary aspergillosis. Correlation between CT findings and pathological features was performed. Results: All lesions presented as a nodule or mass unable to differentiate from malignancy. Most lesions had well-defined margins (n = 4), appeared as solid lesions (n = 7), and were located in the upper lobe (n = 5). Mean diameter of lesions was 2.3 cm. Satellite nodules (n = 2), CT halo sign (n = 1), and hypodense sign (n = 4) were found. Only one lesion increased in size during follow-up. Lesions were pathologically classified as primary aspergilloma (n = 3) and chronic necrotizing pulmonary aspergillosis (n = 4). The hypodense sign on CT was pathologically proved as dense fungal hyphae filled in bronchus and CT halo sign as parenchymal hemorrhage. Conclusion: Pulmonary aspergillosis predominantly presented as a nodule or mass mimicking malignancy in the upper lobes

Pulmonary aspergillosis in immunocompetent patients without air-meniscus sign and underlying lung disease: CT findings and histopathologic features

International Nuclear Information System (INIS)

Yoon, Soon Ho; Park, Chang Min; Goo, Jin Mo; Lee, Hyun Ju

2011-01-01

Background: Pulmonary aspergillosis in immunocompetent patients has been described as a saprophytic infection with pre-existing lung lesions showing an air-meniscus sign on chest radiograph or CT scans. There have been rare articles dealing with pulmonary aspergillosis in immunocompetent patients without pre-existing lung lesions. Purpose: To evaluate the CT findings of pulmonary aspergillosis in immunocompetent patients without air-meniscus and underlying lung disease and to correlate the CT findings and pathologic features of pulmonary aspergillosis in these patients. Material and Methods: A total of seven surgically proven pulmonary aspergillosis found in immunocompetent patients without an air-meniscus and underlying lung disease (M:F = 1:6; mean age 63.4 years) were included. On CT, the lesion shape, margin, type, location, diameter, presence of satellite nodules, presence of CT halo sign or hypodense sign, and interval growth were evaluated. Histopathologic features of each lesion were classified as one of the following; primary aspergilloma, chronic necrotizing pulmonary aspergillosis, or invasive pulmonary aspergillosis. Correlation between CT findings and pathological features was performed. Results: All lesions presented as a nodule or mass unable to differentiate from malignancy. Most lesions had well-defined margins (n = 4), appeared as solid lesions (n = 7), and were located in the upper lobe (n = 5). Mean diameter of lesions was 2.3 cm. Satellite nodules (n = 2), CT halo sign (n = 1), and hypodense sign (n = 4) were found. Only one lesion increased in size during follow-up. Lesions were pathologically classified as primary aspergilloma (n = 3) and chronic necrotizing pulmonary aspergillosis (n = 4). The hypodense sign on CT was pathologically proved as dense fungal hyphae filled in bronchus and CT halo sign as parenchymal hemorrhage. Conclusion: Pulmonary aspergillosis predominantly presented as a nodule or mass mimicking malignancy in the upper lobes

Modelling of tomato stem diameter growth rate based on physiological responses

International Nuclear Information System (INIS)

Li, L.; Tan, J.; Lv, T.

2017-01-01

The stem diameter is an important parameter describing the growth of tomato plant during vegetative growth stage. A stem diameter growth model was developed to predict the response of plant growth under different conditions. By analyzing the diurnal variations of stem diameter in tomato (Solanum lycopersicum L.), it was found that the stem diameter measured at 3:00 am was the representative value as the daily basis of tomato stem diameter. Based on the responses of growth rate in stem diameter to light and temperature, a linear regression relationship was applied to establish the stem diameter growth rate prediction model for the vegetative growth stage in tomato and which was further validated by experiment. The root mean square error (RMSE) and relative error (RE) were used to test the correlation between measured and modeled stem diameter variations. Results showed that the model can be used in prediction for stem diameter growth rate at vegetative growth stage in tomato. (author)