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Sample records for maximum spreading diameter

  1. Prognostic significance of maximum primary tumor diameter in nasopharyngeal carcinoma

    International Nuclear Information System (INIS)

    Liang, Shao-Bo; Deng, Yan-Ming; Zhang, Ning; Lu, Rui-Liang; Zhao, Hai; Chen, Hai-Yang; Li, Shao-En; Liu, Dong-Sheng; Chen, Yong

    2013-01-01

    To evaluate the prognostic value of maximum primary tumor diameter (MPTD) in nasopharyngeal carcinoma (NPC). Three hundred and thirty-three consecutive, newly-diagnosed NPC patients were retrospectively reviewed. Kaplan-Meier analysis and the log-rank test were used to estimate overall survival (OS), failure-free survival (FFS), distant metastasis-free survival (DMFS) and local relapse-free survival (LRFS). Cox proportional hazards regression analysis was used to assess the prognostic value of MPTD. Median follow-up was 66 months (range, 2–82 months). Median MPTD in stage T1, T2, T3 and T4 was 27.9, 37.5, 45.0 and 61.3 mm, respectively. The proportion of T1 patients with a MPTD ≤ 30 mm was 62.3%; 72% and 62.9% of T2 and T3 patients had a MPTD > 30–50 mm, and 83.5% of T4 patients had a MPTD > 50 mm. For patients with a MPTD ≤ 30 mm, > 30–50 mm and > 50 mm, the 5-year OS, FFS, DMFS and LRFS rates were 85.2%, 74.2% and 56.3% (P < 0.001); 87%, 80.7% and 62.8% (P < 0.001); 88.7%, 86.4% and 72.5% (P = 0.003); and 98.2%, 93.2% and 86.3% (P = 0.012), respectively. In multivariate analysis, MPTD was a prognostic factor for OS, FFS and DMFS, and the only independent prognostic factor for LRFS. For T3-T4 patients with a MPTD ≤ 50 mm and > 50 mm, the 5-year OS, FFS and DMFS rates were 70.4% vs. 58.4% (P = 0.010), 77.5% vs. 65.2% (P = 0.013) and 83.6% vs. 73.6% (P = 0.047), respectively. In patients with a MPTD ≤ 30 mm, 5-year LRFS in T1, T2, T3 and T4 was 100%, 100%, 88.9% and 100% (P = 0.172). Our data suggest that MPTD is an independent prognostic factor in NPC, and incorporation of MPTD might lead to a further refinement of T staging

  2. Maximum spreading of liquid drop on various substrates with different wettabilities

    Science.gov (United States)

    Choudhury, Raihan; Choi, Junho; Yang, Sangsun; Kim, Yong-Jin; Lee, Donggeun

    2017-09-01

    This paper describes a novel model developed for a priori prediction of the maximal spread of a liquid drop on a surface. As a first step, a series of experiments were conducted under precise control of the initial drop diameter, its falling height, roughness, and wettability of dry surfaces. The transient liquid spreading was recorded by a high-speed camera to obtain its maximum spreading under various conditions. Eight preexisting models were tested for accurate prediction of the maximum spread; however, most of the model predictions were not satisfactory except one, in comparison with our experimental data. A comparative scaling analysis of the literature models was conducted to elucidate the condition-dependent prediction characteristics of the models. The conditioned bias in the predictions was mainly attributed to the inappropriate formulations of viscous dissipation or interfacial energy of liquid on the surface. Hence, a novel model based on energy balance during liquid impact was developed to overcome the limitations of the previous models. As a result, the present model was quite successful in predicting the liquid spread in all the conditions.

  3. Maximum tumor diameter is not an independent prognostic factor in high-risk localized prostate cancer

    NARCIS (Netherlands)

    Oort, van I.M.; Witjes, J.A.; Kok, D.E.G.; Kiemeney, L.A.; Hulsbergen-van de Kaa, C.A.

    2008-01-01

    Previous studies suggest that maximum tumor diameter (MTD) is a predictor of recurrence in prostate cancer (PC). This study investigates the prognostic value of MTD for biochemical recurrence (BCR) in patients with PC, after radical prostatectomy (RP), with emphasis on high-risk localized prostate

  4. Influence of Thread Root Radius on Maximum Local Stresses at Large Diameter Bolts under Axial Loading

    Directory of Open Access Journals (Sweden)

    Cojocaru Vasile

    2014-06-01

    Full Text Available In the thread root area of the threaded bolts submitted to axial loading occur local stresses, higher that nominal stresses calculated for the bolts. These local stresses can generate failure and can reduce the fatigue life of the parts. The paper is focused on the study of the influence of the thread root radius on the maximum local stresses. A large diameter trapezoidal bolt was subjected to a static analysis (axial loading using finite element simulation.

  5. 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.

  6. 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.

  7. Maximum Diameter and Number of Tumors as a New Prognostic Indicator of Colorectal Liver Metastases.

    Science.gov (United States)

    Yoshimoto, Toshiaki; Morine, Yuji; Imura, Satoru; Ikemoto, Tetsuya; Iwahashi, Syuichi; Saito, Y U; Yamada, Sinichiro; Ishikawa, Daichi; Teraoku, Hiroki; Yoshikawa, Masato; Higashijima, Jun; Takasu, Chie; Shimada, Mitsuo

    2017-01-01

    Surgical resection is currently considered the only potentially curative option as a treatment strategy of colorectal liver metastases (CRLM). However, the criteria for selection of resectable CRLM are not clear. The aim of this study was to confirm a new prognostic indicator of CRLM after hepatic resection. One hundred thirty nine patients who underwent initial surgical resection from 1994 to 2015 were investigated retrospectively. Prognostic factors of overall survival including the product of maximum diameter and number of metastases (MDN) were analyzed. Primary tumor differentiation, vessel invasion, lymph node (LN) metastasis, non-optimally resectable metastases, H score, grade of liver metastases, resection with non-curative intent and MDN were found to be prognostic factors of overall survival (OS). In multivariate analyses of clinicopathological features associated with OS, MDN and non-curative intent were independent prognostic factors. Patients with MDN ≥30 had shown significantly poorer prognosis than patients with MDN <30 in OS and relapse-free survival (RFS). MDN ≥30 is an independent prognostic factor of survival in patients with CRLM and optimal surgical criterion of hepatectomy for CRLM. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

  8. Novel Maximum-based Timing Acquisition for Spread-Spectrum Communications

    Energy Technology Data Exchange (ETDEWEB)

    Sibbetty, Taylor; Moradiz, Hussein; Farhang-Boroujeny, Behrouz

    2016-12-01

    This paper proposes and analyzes a new packet detection and timing acquisition method for spread spectrum systems. The proposed method provides an enhancement over the typical thresholding techniques that have been proposed for direct sequence spread spectrum (DS-SS). The effective implementation of thresholding methods typically require accurate knowledge of the received signal-to-noise ratio (SNR), which is particularly difficult to estimate in spread spectrum systems. Instead, we propose a method which utilizes a consistency metric of the location of maximum samples at the output of a filter matched to the spread spectrum waveform to achieve acquisition, and does not require knowledge of the received SNR. Through theoretical study, we show that the proposed method offers a low probability of missed detection over a large range of SNR with a corresponding probability of false alarm far lower than other methods. Computer simulations that corroborate our theoretical results are also presented. Although our work here has been motivated by our previous study of a filter bank multicarrier spread-spectrum (FB-MC-SS) system, the proposed method is applicable to DS-SS systems as well.

  9. 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.

  10. Superior Reproducibility of the Leading to Leading Edge and Inner to Inner Edge Methods in the Ultrasound Assessment of Maximum Abdominal Aortic Diameter

    DEFF Research Database (Denmark)

    Borgbjerg, Jens; Bøgsted, Martin; Lindholt, Jes S

    2018-01-01

    Objectives: Controversy exists regarding optimal caliper placement in ultrasound assessment of maximum abdominal aortic diameter. This study aimed primarily to determine reproducibility of caliper placement in relation to the aortic wall with the three principal methods: leading to leading edge...

  11. Sensitivity of C-Band Polarimetric Radar-Based Drop Size Distribution Measurements to Maximum Diameter Assumptions

    Science.gov (United States)

    Carey, Lawrence D.; Petersen, Walter A.

    2011-01-01

    The estimation of rain drop size distribution (DSD) parameters from polarimetric radar observations is accomplished by first establishing a relationship between differential reflectivity (Z(sub dr)) and the central tendency of the rain DSD such as the median volume diameter (D0). Since Z(sub dr) does not provide a direct measurement of DSD central tendency, the relationship is typically derived empirically from rain drop and radar scattering models (e.g., D0 = F[Z (sub dr)] ). Past studies have explored the general sensitivity of these models to temperature, radar wavelength, the drop shape vs. size relation, and DSD variability. Much progress has been made in recent years in measuring the drop shape and DSD variability using surface-based disdrometers, such as the 2D Video disdrometer (2DVD), and documenting their impact on polarimetric radar techniques. In addition to measuring drop shape, another advantage of the 2DVD over earlier impact type disdrometers is its ability to resolve drop diameters in excess of 5 mm. Despite this improvement, the sampling limitations of a disdrometer, including the 2DVD, make it very difficult to adequately measure the maximum drop diameter (D(sub max)) present in a typical radar resolution volume. As a result, D(sub max) must still be assumed in the drop and radar models from which D0 = F[Z(sub dr)] is derived. Since scattering resonance at C-band wavelengths begins to occur in drop diameters larger than about 5 mm, modeled C-band radar parameters, particularly Z(sub dr), can be sensitive to D(sub max) assumptions. In past C-band radar studies, a variety of D(sub max) assumptions have been made, including the actual disdrometer estimate of D(sub max) during a typical sampling period (e.g., 1-3 minutes), D(sub max) = C (where C is constant at values from 5 to 8 mm), and D(sub max) = M*D0 (where the constant multiple, M, is fixed at values ranging from 2.5 to 3.5). The overall objective of this NASA Global Precipitation Measurement

  12. Superior Reproducibility of the Leading to Leading Edge and Inner to Inner Edge Methods in the Ultrasound Assessment of Maximum Abdominal Aortic Diameter.

    Science.gov (United States)

    Borgbjerg, Jens; Bøgsted, Martin; Lindholt, Jes S; Behr-Rasmussen, Carsten; Hørlyck, Arne; Frøkjær, Jens B

    2018-02-01

    Controversy exists regarding optimal caliper placement in ultrasound assessment of maximum abdominal aortic diameter. This study aimed primarily to determine reproducibility of caliper placement in relation to the aortic wall with the three principal methods: leading to leading edge (LTL), inner to inner edge (ITI), and outer to outer edge (OTO). The secondary aim was to assess the mean difference between the OTO, ITI, and LTL diameters and estimate the impact of using either of these methods on abdominal aortic aneurysm (AAA) prevalence in a screening program. Radiologists (n=18) assessed the maximum antero-posterior abdominal aortic diameter by completing repeated caliper placements with the OTO, LTL, and ITI methods on 50 still abdominal aortic images obtained from an AAA screening program. Inter-observer reproducibility was calculated as the limit of agreement with the mean (LoA), which represents expected deviation of a single observer from the mean of all observers. Intra-observer reproducibility was assessed averaging the LoA for each observer with their repeated measurements. Based on data from an AAA screening trial and the estimated mean differences between the three principal methods, AAA prevalence was estimated using each of the methods. The inter-observer LoA of the OTO, ITI, and LTL was 2.6, 1.9, and 1.9 mm, whereas the intra-observer LoA was 2.0, 1.6, and 1.5 mm, respectively. Mean differences of 5.0 mm were found between OTO and ITI measurements, 2.6 mm between OTO and LTL measurements, and 2.4 mm between LTL and ITI measurements. The prevalence of AAA almost doubled using OTO instead of ITI, while the difference between ITI and LTL was minor (3.3% vs. 4.0% AAA). The study shows superior reproducibility of LTL and ITI compared with the OTO method of caliper placement in ultrasound determination of maximum abdominal aortic diameter, and the choice of caliper placement method significantly affects the prevalence of AAAs in screening programs

  13. Radiofrequency Ablation Using a Multiple-Electrode Switching System for Lung Tumors with 2.0-5.0-cm Maximum Diameter: Phase II Clinical Study.

    Science.gov (United States)

    Kodama, Hiroshi; Yamakado, Koichiro; Hasegawa, Takaaki; Fujimori, Masashi; Yamanaka, Takashi; Takaki, Haruyuki; Uraki, Junji; Nakatsuka, Atsuhiro; Sakuma, Hajime

    2015-12-01

    To prospectively evaluate the safety and effectiveness of radiofrequency ablation (RFA) by using a multiple-electrode switching system to treat 2.0-5.0-cm lung tumors. The institutional review board approved this prospective phase II study. Written informed consent was obtained from all patients. Between September 2009 and July 2011, RFA using two or three radiofrequency (RF) electrodes and a multiple-electrode switching system was performed for malignant lung tumors with a maximum tumor diameter of 2.0-5.0 cm in nonsurgical candidates. The primary endpoint was safety, as evaluated using the Common Terminology Criteria for Adverse Events. Patients were observed for at least 1 year. Local tumor progression and overall survival were analyzed with the Kaplan-Meier method. Thirty-three patients (26 men, seven women; mean age, 70.5 years ± 10.0; age range, 46-87 years) with 35 lung tumors with a mean maximum diameter of 3.0 cm ± 0.7 (standard deviation; range, 2.0-4.4 cm) underwent treatment in 35 sessions. No procedure-related death or grade 4 adverse events (AEs) occurred. Grade 3 AEs occurred in four patients (12%), with pleural effusion requiring chest tube placement in two patients, pneumothorax requiring pleural adhesion in one patient, and pulmonary hemorrhage requiring pulmonary artery coil embolization in one patient. Grade 2 AEs were detected in 13 patients (39%). The 1-year local tumor progression and overall survival rates were 12.7% (95% confidence interval [CI]: 1.0, 25.5) and 81.2% (95% CI: 67.6, 94.8). RFA with a multiple-electrode switching system may be a safe therapeutic option with which to treat 2.0-5.0-cm lung cancer tumors.

  14. Larger Maximum Tumor Diameter at Radical Prostatectomy Is Associated With Increased Biochemical Failure, Metastasis, and Death From Prostate Cancer After Salvage Radiation for Prostate Cancer

    International Nuclear Information System (INIS)

    Johnson, Skyler B.; Hamstra, Daniel A.; Jackson, William C.; Zhou, Jessica; Foster, Benjamin; Foster, Corey; Song, Yeohan; Li, Darren; Palapattu, Ganesh S.; Kunju, Lakshmi; Mehra, Rohit; Sandler, Howard; Feng, Felix Y.

    2013-01-01

    Purpose: To investigate the maximum tumor diameter (MTD) of the dominant prostate cancer nodule in the radical prostatectomy specimen as a prognostic factor for outcome in patients treated with salvage external beam radiation therapy (SRT) for a rising prostate-specific antigen (PSA) value after radical prostatectomy. Methods and Materials: From an institutional cohort of 575 patients treated with SRT, data on MTD were retrospectively collected. The impact of MTD on biochemical failure (BF), metastasis, and prostate cancer-specific mortality (PCSM) was assessed on univariate and multivariate analysis using Kaplan-Meier and Cox proportional hazards models. Results: In the 173 patients with MTD data available, median follow-up was 77 months (interquartile range, 47-104 months) after SRT, and median MTD was 18 mm (interquartile range, 13-22 mm). Increasing MTD correlated with increasing pT stage, Gleason score, presence of seminal vesicle invasion, and lymph node invasion. Receiver operating characteristic curve analysis identified MTD of >14 mm to be the optimal cut-point. On univariate analysis, MTD >14 mm was associated with an increased risk of BF (P=.02, hazard ratio [HR] 1.8, 95% confidence interval [CI] 1.2-2.8), metastasis (P=.002, HR 4.0, 95% CI 2.1-7.5), and PCSM (P=.02, HR 8.0, 95% CI 2.9-21.8). On multivariate analysis MTD >14 mm remained associated with increased BF (P=.02, HR 1.9, 95% CI 1.1-3.2), metastasis (P=.02, HR 3.4, 95% CI 1.2-9.2), and PCSM (P=.05, HR 9.7, 95% CI 1.0-92.4), independent of extracapsular extension, seminal vesicle invasion, positive surgical margins, pre-RT PSA value, Gleason score, and pre-RT PSA doubling time. Conclusions: For patients treated with SRT for a rising PSA value after prostatectomy, MTD at time of radical prostatectomy is independently associated with BF, metastasis, and PCSM. Maximum tumor diameter should be incorporated into clinical decision making and future clinical risk assessment tools for those patients

  15. Interference Cancellation Technique Based on Discovery of Spreading Codes of Interference Signals and Maximum Correlation Detection for DS-CDMA System

    Science.gov (United States)

    Hettiarachchi, Ranga; Yokoyama, Mitsuo; Uehara, Hideyuki

    This paper presents a novel interference cancellation (IC) scheme for both synchronous and asynchronous direct-sequence code-division multiple-access (DS-CDMA) wireless channels. In the DS-CDMA system, the multiple access interference (MAI) and the near-far problem (NFP) are the two factors which reduce the capacity of the system. In this paper, we propose a new algorithm that is able to detect all interference signals as an individual MAI signal by maximum correlation detection. It is based on the discovery of all the unknowing spreading codes of the interference signals. Then, all possible MAI patterns so called replicas are generated as a summation of interference signals. And the true MAI pattern is found by taking correlation between the received signal and the replicas. Moreover, the receiver executes MAI cancellation in a successive manner, removing all interference signals by single-stage. Numerical results will show that the proposed IC strategy, which alleviates the detrimental effect of the MAI and the near-far problem, can significantly improve the system performance. Especially, we can obtain almost the same receiving characteristics as in the absense of interference for asynchrnous system when received powers are equal. Also, the same performances can be seen under any received power state for synchronous system.

  16. Determining the maximum diameter for holes in the shoe without compromising shoe integrity when using a multi-segment foot model.

    Science.gov (United States)

    Shultz, Rebecca; Jenkyn, Thomas

    2012-01-01

    Measuring individual foot joint motions requires a multi-segment foot model, even when the subject is wearing a shoe. Each foot segment must be tracked with at least three skin-mounted markers, but for these markers to be visible to an optical motion capture system holes or 'windows' must be cut into the structure of the shoe. The holes must be sufficiently large avoiding interfering with the markers, but small enough that they do not compromise the shoe's structural integrity. The objective of this study was to determine the maximum size of hole that could be cut into a running shoe upper without significantly compromising its structural integrity or changing the kinematics of the foot within the shoe. Three shoe designs were tested: (1) neutral cushioning, (2) motion control and (3) stability shoes. Holes were cut progressively larger, with four sizes tested in all. Foot joint motions were measured: (1) hindfoot with respect to midfoot in the frontal plane, (2) forefoot twist with respect to midfoot in the frontal plane, (3) the height-to-length ratio of the medial longitudinal arch and (4) the hallux angle with respect to first metatarsal in the sagittal plane. A single subject performed level walking at her preferred pace in each of the three shoes with ten repetitions for each hole size. The largest hole that did not disrupt shoe integrity was an oval of 1.7cm×2.5cm. The smallest shoe deformations were seen with the motion control shoe. The least change in foot joint motion was forefoot twist in both the neutral shoe and stability shoe for any size hole. This study demonstrates that for a hole smaller than this size, optical motion capture with a cluster-based multi-segment foot model is feasible for measure foot in shoe kinematics in vivo. Copyright © 2011. Published by Elsevier Ltd.

  17. Concurrent study of bottomside spread F and plasma bubble events in the equatorial ionosphere during solar maximum using digisonde and ROCSAT-1

    Directory of Open Access Journals (Sweden)

    C.-C. Lee

    2005-12-01

    Full Text Available Data from the Jicamarca digisonde and the ROCSAT-1 satellite are employed to study the equatorial ionosphere on the west side of South America during April 1999-March 2000 for the concurrent bottomside spread F (BSSF and plasma bubble events. This study, using digisonde and ROCSAT-1 concurrently, is the first attempt to investigate the equatorial spread F. Results show that BSSF and plasma bubble observations appear frequently respectively in the summer (January, February, November, and December and in the equinoctial (March, April, September, and October months, respectively, but are both rarely observed in the winter (May-August months. The upward drift velocity during the concurrent BSSF and bubble observations has been determined to study the driving mechanism. This analysis shows that large vertical drift velocities favor BSSF and bubble formations in the equinoctial and summer months. Conversely, the smaller upward velocities during the winter months cause fewer BSSF and bubble occurrences. For the geomagnetic effect, the BSSF/bubble occurrence decreases with an increasing Kp value in the equinoctial months, but no such correlation is found for the summer and winter months. Moreover, the anti-correlations between Kp and dh'F/dt are apparent in the equinoctial months, but not in the summer and winter months. These results indicate that in the equinoctial months the BSSF/bubble generations and the pre-reversal drift velocity can be suppressed by geomagnetic activity, because the disturbance dynamo effects could have decreased the eastward electric field near sunset. However, BSSF and bubble occurrences may not be suppressed by the geomagnetic activity in the summer and winter months.

  18. Concurrent study of bottomside spread F and plasma bubble events in the equatorial ionosphere during solar maximum using digisonde and ROCSAT-1

    Directory of Open Access Journals (Sweden)

    C.-C. Lee

    2005-12-01

    Full Text Available Data from the Jicamarca digisonde and the ROCSAT-1 satellite are employed to study the equatorial ionosphere on the west side of South America during April 1999-March 2000 for the concurrent bottomside spread F (BSSF and plasma bubble events. This study, using digisonde and ROCSAT-1 concurrently, is the first attempt to investigate the equatorial spread F. Results show that BSSF and plasma bubble observations appear frequently respectively in the summer (January, February, November, and December and in the equinoctial (March, April, September, and October months, respectively, but are both rarely observed in the winter (May-August months. The upward drift velocity during the concurrent BSSF and bubble observations has been determined to study the driving mechanism. This analysis shows that large vertical drift velocities favor BSSF and bubble formations in the equinoctial and summer months. Conversely, the smaller upward velocities during the winter months cause fewer BSSF and bubble occurrences. For the geomagnetic effect, the BSSF/bubble occurrence decreases with an increasing Kp value in the equinoctial months, but no such correlation is found for the summer and winter months. Moreover, the anti-correlations between Kp and dh'F/dt are apparent in the equinoctial months, but not in the summer and winter months. These results indicate that in the equinoctial months the BSSF/bubble generations and the pre-reversal drift velocity can be suppressed by geomagnetic activity, because the disturbance dynamo effects could have decreased the eastward electric field near sunset. However, BSSF and bubble occurrences may not be suppressed by the geomagnetic activity in the summer and winter months.

  19. The effects of the pre-reversal ExB drift, the EIA asymmetry, and magnetic activity on the equatorial spread F during solar maximum

    Directory of Open Access Journals (Sweden)

    C.-C. Lee

    2005-03-01

    Full Text Available We use a digisonde at Jicamarca and a chain of GPS receivers on the west side of South America to investigate the effects of the pre-reversal enhancement (PRE in ExB drift, the asymmetry (Ia of equatorial ionization anomaly (EIA, and the magnetic activity (Kp on the generation of equatorial spread F (ESF. Results show that the ESF appears frequently in summer (November, December, January, and February and equinoctial (March, April, September, and October months, but rarely in winter (May, June, July, and August months. The seasonal variation in the ESF is associated with those in the PRE ExB drift and Ia. The larger ExB drift (>20m/s and smaller |Ia| (<0.3 in summer and equinoctial months provide a preferable condition to development the ESF. Conversely, the smaller ExB drift and larger |Ia| are responsible for the lower ESF occurrence in winter months. Regarding the effects of magnetic activity, the ESF occurrence decreases with increasing Kp in the equinoctial and winter months, but not in the summer months. Furthermore, the larger and smaller ExB drifts are presented under the quiet (Kp<3 and disturbed (Kp≥3 conditions, respectively. These results indicate that the suppression in ESF and the decrease in ExB drifts are mainly caused by the decrease in the eastward electric field.

  20. The effects of the pre-reversal ExB drift, the EIA asymmetry, and magnetic activity on the equatorial spread F during solar maximum

    Directory of Open Access Journals (Sweden)

    C.-C. Lee

    2005-03-01

    Full Text Available We use a digisonde at Jicamarca and a chain of GPS receivers on the west side of South America to investigate the effects of the pre-reversal enhancement (PRE in ExB drift, the asymmetry (Ia of equatorial ionization anomaly (EIA, and the magnetic activity (Kp on the generation of equatorial spread F (ESF. Results show that the ESF appears frequently in summer (November, December, January, and February and equinoctial (March, April, September, and October months, but rarely in winter (May, June, July, and August months. The seasonal variation in the ESF is associated with those in the PRE ExB drift and Ia. The larger ExB drift (>20m/s and smaller |Ia| (<0.3 in summer and equinoctial months provide a preferable condition to development the ESF. Conversely, the smaller ExB drift and larger |Ia| are responsible for the lower ESF occurrence in winter months. Regarding the effects of magnetic activity, the ESF occurrence decreases with increasing Kp in the equinoctial and winter months, but not in the summer months. Furthermore, the larger and smaller ExB drifts are presented under the quiet (Kp<3 and disturbed (Kp≥3 conditions, respectively. These results indicate that the suppression in ESF and the decrease in ExB drifts are mainly caused by the decrease in the eastward electric field.

  1. Optimizing hybrid spreading in metapopulations.

    Science.gov (United States)

    Zhang, Changwang; Zhou, Shi; Miller, Joel C; Cox, Ingemar J; Chain, Benjamin M

    2015-04-29

    Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemics, and examine the optimum balance between spreading mechanisms in terms of achieving the maximum outbreak size. We show the existence of critically hybrid epidemics where neither spreading mechanism alone can cause a noticeable spread but a combination of the two spreading mechanisms would produce an enormous outbreak. Our results provide new strategies for maximising beneficial epidemics and estimating the worst outcome of damaging hybrid epidemics.

  2. 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).

  3. Determination of Aerosol Particle Diameter Using Cascade Impactor Procedure

    International Nuclear Information System (INIS)

    Bunawas; Ruslanto, P. O

    1998-01-01

    Determination of aerosol particle size distribution has been done using a low pressure Andersen's cascade impactor with 13 stages. The aerosol has been sampled with flow rate of aerosol sampling of 28.3 Ipm. Preliminary study result shows that aerosol in the simulation chamber was spread in monomodal distribution with Mass Median Aerodynamic Diameter of 4.9 μm. The aerosol measurement in Japan Power Demonstration Reactor has been spread in trimodal distribution with Activity Median Aerodynamic Diameter equal to 13.3 μm. The use of mylar as impaction plate instead of aluminum foil gives good result

  4. How Is Mono Spread?

    Science.gov (United States)

    ... How Is Mono Spread? Print My sister has mononucleosis. I drank out of her drink before we ... that I have mono now? – Kyle* Mono, or mononucleosis, is spread through direct contact with saliva. This ...

  5. Vessel diameter measurements in gadolinium contrast-enhanced three-dimensional MRA of peripheral arteries

    NARCIS (Netherlands)

    Westenberg, J.J.M.; Geest, van der R.J.; Wasser, M.N.J.M.; Linden, van der E.L.; Walsum, van T.; Assen, van H.C.; Roos, de A.; Vanderschoot, J.; Reiber, J.H.C.

    2000-01-01

    In this study, the possibilities for quantification of vessel diameters of peripheral arteries in gadolinium contrast-enhanced magnetic resonance angiography (Gd CE MRA) were evaluated. Absolute vessel diameter measurements were assessed objectively and semi-automatically in maximum intensity

  6. DESIGN OF PARTICULATE MATERIAL COMPACTOR ROLLS DIAMETER

    Directory of Open Access Journals (Sweden)

    Peter Peciar

    2017-09-01

    Full Text Available At present, in a period of an industrial expansion great emphasis is placed on the environment. That means aiming for a reduced energy consumption, and also lessening dustiness from very fine powder material. This category also includes particulate material agglomeration processes. Because this process is very energy-intensive, it is necessary to correctly design these devices. The aim of this paper is to focus on a theoretical design of a production compactor with the rolls diameter for an experimental particulate material, based on Johanson’s theory and experimentally measured material properties. The material used for experimental measurements was an NPK-based industrial fertilizer consisting of several components. The results of this paper is the dependence of the ratio of the maximum compression pressure to the initial compression pressure from the rolls diameter of the proposed compactor.

  7. 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

  8. 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

  9. Seasonal variations of equatorial spread-F

    Directory of Open Access Journals (Sweden)

    B. V. Krishna Murthy

    Full Text Available The occurrence of spread-F at Trivandrum (8.5°N, 77°E, dip 0.5°N has been investigated on a seasonal basis in sunspot maximum and minimum years in terms of the growth rate of irregularities by the generalized collisional Rayleigh-Taylor (GRT instability mechanism which includes the gravitational and cross-field instability terms. The occurrence statistics of spread-F at Trivandrum have been obtained using quarter hourly ionograms. The nocturnal variations of the growth rate of irregularities by the GRT mechanism have been estimated for different seasons in sunspot maximum and minimum years at Trivandrum using h'F values and vertical drift velocities obtained from ionograms. It is found that the seasonal variation of spread-F occurrence at Trivandrum can, in general, be accounted for on the basis of the GRT mechanism.

  10. Seasonal variations of equatorial spread-F

    Directory of Open Access Journals (Sweden)

    K. S. V. Subbarao

    1994-01-01

    Full Text Available The occurrence of spread-F at Trivandrum (8.5°N, 77°E, dip 0.5°N has been investigated on a seasonal basis in sunspot maximum and minimum years in terms of the growth rate of irregularities by the generalized collisional Rayleigh-Taylor (GRT instability mechanism which includes the gravitational and cross-field instability terms. The occurrence statistics of spread-F at Trivandrum have been obtained using quarter hourly ionograms. The nocturnal variations of the growth rate of irregularities by the GRT mechanism have been estimated for different seasons in sunspot maximum and minimum years at Trivandrum using h'F values and vertical drift velocities obtained from ionograms. It is found that the seasonal variation of spread-F occurrence at Trivandrum can, in general, be accounted for on the basis of the GRT mechanism.

  11. Optimizing Hybrid Spreading in Metapopulations.

    OpenAIRE

    Zhang, C.; Zhou, S.; Miller, J. C.; Cox, I. J.; Chain, B. M.

    2015-01-01

    Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemic...

  12. Optimizing Hybrid Spreading in Metapopulations

    OpenAIRE

    Zhang, Changwang; Zhou, Shi; Miller, Joel C.; Cox, Ingemar J.; Chain, Benjamin M.

    2014-01-01

    Epidemic spreading phenomena are ubiquitous in nature and society. Examples include the spreading of diseases, information, and computer viruses. Epidemics can spread by local spreading, where infected nodes can only infect a limited set of direct target nodes and global spreading, where an infected node can infect every other node. In reality, many epidemics spread using a hybrid mixture of both types of spreading. In this study we develop a theoretical framework for studying hybrid epidemic...

  13. Spread effects - methodology

    International Nuclear Information System (INIS)

    2004-01-01

    Diffusion of technology, environmental effects and rebound effects are the principal effects from the funding of renewable energy and energy economising. It is difficult to estimate the impact of the spread effects both prior to the measures are implemented and after the measures are carried out. Statistical methods can be used to estimate the spread effects, but they are insecure and always need to be complemented with qualitative and subjective evaluations. It is more adequate to evaluate potential spread effects from market and market data surveillance for a selection of technologies and parties. Based on this information qualitative indicators for spread effects can be constructed and used both ex ante and ex post (ml)

  14. Ocean, Spreading Centre

    Digital Repository Service at National Institute of Oceanography (India)

    Krishna, K.S.

    over the global midoceanic ridges have found some explicit relationships between spreading rate, seismic structure, and ridge-axis morphology. Bibliography Detrick, R. S., Buhl, P., Vera, E., Mutter, J., Orcutt, J., Madsen, J., and Brocher, T., 1987...

  15. The VULCANO spreading programme

    Energy Technology Data Exchange (ETDEWEB)

    Cognet, G.; Laffont, G.; Jegou, C.; Journeau, C.; Sudreau, F.; Pierre, J.; Ramacciotti, M. [CEA (Atomic Energy Commission), DRN/DER - Bat. 212, CEA Cadarache, 13108 St. Paul Lez Durance (France)

    1999-07-01

    Among the currently studied core-catcher projects, some of them suppose corium spreading before cooling, in particular the EPR (European Pressurized Reactor) core-catcher concept is based on mixing the corium with a special concrete, spreading the molten mixture on a large multi-layer surface cooled from the bottom and subsequently cooling by flooding with water. Therefore, melt spreading deserves intensive investigation in order to determine and quantify key phenomena which govern the stopping of spreading. In France, for some years, the Nuclear Reactor Division of the Atomic Energy Commission (CEA/DRN) has undertaken a large program to improve knowledge on corium behaviour and coolability. This program is based on experimental and theoretical investigations which are finally gathered in scenario and mechanistic computer codes. In this framework, the real material experimental programme, VULCANO, conducted within an European frame, is currently devoted to the study of corium spreading. In 1997 and 1998, several tests have been performed on dry corium spreading with various composition of melts. Although all the observed phenomena, in particular the differences between simulant and real material melts have not been yet totally explained, these tests have already provided a lot of information about: The behaviour of complex mixtures including refractory oxides, silica, iron oxides and in one case iron metal; Spreading progression, which was never stopped in any of these tests by a crust formation at the front; The structure of spread melts (porosity, crusts,...); Physico-chemical interaction between melt and the refractory substratum which was composed of zirconia bricks. (authors)

  16. The VULCANO spreading programme

    International Nuclear Information System (INIS)

    Cognet, G.; Laffont, G.; Jegou, C.; Journeau, C.; Sudreau, F.; Pierre, J.; Ramacciotti, M.

    1999-01-01

    Among the currently studied core-catcher projects, some of them suppose corium spreading before cooling, in particular the EPR (European Pressurized Reactor) core-catcher concept is based on mixing the corium with a special concrete, spreading the molten mixture on a large multi-layer surface cooled from the bottom and subsequently cooling by flooding with water. Therefore, melt spreading deserves intensive investigation in order to determine and quantify key phenomena which govern the stopping of spreading. In France, for some years, the Nuclear Reactor Division of the Atomic Energy Commission (CEA/DRN) has undertaken a large program to improve knowledge on corium behaviour and coolability. This program is based on experimental and theoretical investigations which are finally gathered in scenario and mechanistic computer codes. In this framework, the real material experimental programme, VULCANO, conducted within an European frame, is currently devoted to the study of corium spreading. In 1997 and 1998, several tests have been performed on dry corium spreading with various composition of melts. Although all the observed phenomena, in particular the differences between simulant and real material melts have not been yet totally explained, these tests have already provided a lot of information about: The behaviour of complex mixtures including refractory oxides, silica, iron oxides and in one case iron metal; Spreading progression, which was never stopped in any of these tests by a crust formation at the front; The structure of spread melts (porosity, crusts,...); Physico-chemical interaction between melt and the refractory substratum which was composed of zirconia bricks. (authors)

  17. Approximate maximum parsimony and ancestral maximum likelihood.

    Science.gov (United States)

    Alon, Noga; Chor, Benny; Pardi, Fabio; Rapoport, Anat

    2010-01-01

    We explore the maximum parsimony (MP) and ancestral maximum likelihood (AML) criteria in phylogenetic tree reconstruction. Both problems are NP-hard, so we seek approximate solutions. We formulate the two problems as Steiner tree problems under appropriate distances. The gist of our approach is the succinct characterization of Steiner trees for a small number of leaves for the two distances. This enables the use of known Steiner tree approximation algorithms. The approach leads to a 16/9 approximation ratio for AML and asymptotically to a 1.55 approximation ratio for MP.

  18. Maximum permissible dose

    International Nuclear Information System (INIS)

    Anon.

    1979-01-01

    This chapter presents a historic overview of the establishment of radiation guidelines by various national and international agencies. The use of maximum permissible dose and maximum permissible body burden limits to derive working standards is discussed

  19. Diameter dependent failure current density of gold nanowires

    International Nuclear Information System (INIS)

    Karim, S; Maaz, K; Ali, G; Ensinger, W

    2009-01-01

    Failure current density of single gold nanowires is investigated in this paper. Single wires with diameters ranging from 80 to 720 nm and length 30 μm were electrochemically deposited in ion track-etched single-pore polycarbonate membranes. The maximum current density was investigated while keeping the wires embedded in the polymer matrix and ramping up the current until failure occurred. The current density is found to increase with diminishing diameter and the wires with a diameter of 80 nm withstand 1.2 x 10 12 A m -2 before undergoing failure. Possible reasons for these results are discussed in this paper.

  20. Spread of Canine Flu

    Centers for Disease Control (CDC) Podcasts

    2018-04-05

    Dr. Colin Parrish, a Professor of Virology at the College of Veterinary Medicine, Cornell University, discusses the spread of influenza among dogs.  Created: 4/5/2018 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 4/5/2018.

  1. 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

  2. 40 CFR 1042.140 - Maximum engine power, displacement, power density, and maximum in-use engine speed.

    Science.gov (United States)

    2010-07-01

    ... cylinders having an internal diameter of 13.0 cm and a 15.5 cm stroke length, the rounded displacement would... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Maximum engine power, displacement... Maximum engine power, displacement, power density, and maximum in-use engine speed. This section describes...

  3. Combinatorics of spreads and parallelisms

    CERN Document Server

    Johnson, Norman

    2010-01-01

    Partitions of Vector Spaces Quasi-Subgeometry Partitions Finite Focal-SpreadsGeneralizing André SpreadsThe Going Up Construction for Focal-SpreadsSubgeometry Partitions Subgeometry and Quasi-Subgeometry Partitions Subgeometries from Focal-SpreadsExtended André SubgeometriesKantor's Flag-Transitive DesignsMaximal Additive Partial SpreadsSubplane Covered Nets and Baer Groups Partial Desarguesian t-Parallelisms Direct Products of Affine PlanesJha-Johnson SL(2,

  4. Spread spectrum image steganography.

    Science.gov (United States)

    Marvel, L M; Boncelet, C R; Retter, C T

    1999-01-01

    In this paper, we present a new method of digital steganography, entitled spread spectrum image steganography (SSIS). Steganography, which means "covered writing" in Greek, is the science of communicating in a hidden manner. Following a discussion of steganographic communication theory and review of existing techniques, the new method, SSIS, is introduced. This system hides and recovers a message of substantial length within digital imagery while maintaining the original image size and dynamic range. The hidden message can be recovered using appropriate keys without any knowledge of the original image. Image restoration, error-control coding, and techniques similar to spread spectrum are described, and the performance of the system is illustrated. A message embedded by this method can be in the form of text, imagery, or any other digital signal. Applications for such a data-hiding scheme include in-band captioning, covert communication, image tamperproofing, authentication, embedded control, and revision tracking.

  5. Maximum Acceleration Recording Circuit

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

  6. Spreading convulsions, spreading depolarization and epileptogenesis in human cerebral cortex

    DEFF Research Database (Denmark)

    Dreier, Jens P; Major, Sebastian; Pannek, Heinz-Wolfgang

    2012-01-01

    Spreading depolarization of cells in cerebral grey matter is characterized by massive ion translocation, neuronal swelling and large changes in direct current-coupled voltage recording. The near-complete sustained depolarization above the inactivation threshold for action potential generating...... stimulations. Eventually, epileptic field potentials were recorded during the period that had originally seen spreading depression of activity. Such spreading convulsions are characterized by epileptic field potentials on the final shoulder of the large slow potential change of spreading depolarization. We...

  7. Maximum Quantum Entropy Method

    OpenAIRE

    Sim, Jae-Hoon; Han, Myung Joon

    2018-01-01

    Maximum entropy method for analytic continuation is extended by introducing quantum relative entropy. This new method is formulated in terms of matrix-valued functions and therefore invariant under arbitrary unitary transformation of input matrix. As a result, the continuation of off-diagonal elements becomes straightforward. Without introducing any further ambiguity, the Bayesian probabilistic interpretation is maintained just as in the conventional maximum entropy method. The applications o...

  8. Maximum power demand cost

    International Nuclear Information System (INIS)

    Biondi, L.

    1998-01-01

    The charging for a service is a supplier's remuneration for the expenses incurred in providing it. There are currently two charges for electricity: consumption and maximum demand. While no problem arises about the former, the issue is more complicated for the latter and the analysis in this article tends to show that the annual charge for maximum demand arbitrarily discriminates among consumer groups, to the disadvantage of some [it

  9. Estimation of wave directional spreading

    Digital Repository Service at National Institute of Oceanography (India)

    Deo, M.C.; Gondane, D.S.; SanilKumar, V.

    One of the useful measures of waves directional spreading at a given location is the directional spreading parameter. This paper presents a new approach to arrive at its characteristic value using the computational technique of Artificial Neural...

  10. Illusory spreading of watercolor.

    Science.gov (United States)

    Devinck, Frédéric; Hardy, Joseph L; Delahunt, Peter B; Spillmann, Lothar; Werner, John S

    2006-05-04

    The watercolor effect (WCE) is a phenomenon of long-range color assimilation occurring when a dark chromatic contour delineating a figure is flanked on the inside by a brighter chromatic contour; the brighter color spreads into the entire enclosed area. Here, we determined the optimal chromatic parameters and the cone signals supporting the WCE. To that end, we quantified the effect of color assimilation using hue cancellation as a function of hue, colorimetric purity, and cone modulation of inducing contours. When the inner and outer contours had chromaticities that were in opposite directions in color space, a stronger WCE was obtained as compared with other color directions. Additionally, equal colorimetric purity between the outer and inner contours was necessary to obtain a large effect compared with conditions in which the contours differed in colorimetric purity. However, there was no further increase in the magnitude of the effect when the colorimetric purity increased beyond a value corresponding to an equal vector length between the inner and outer contours. Finally, L-M-cone-modulated WCE was perceptually stronger than S-cone-modulated WCE for our conditions. This last result demonstrates that both L-M-cone and S-cone pathways are important for watercolor spreading. Our data suggest that the WCE depends critically upon the particular spatiochromatic arrangement in the display, with the relative chromatic contrast between the inducing contours being particularly important.

  11. Hybrid spread spectrum radio system

    Science.gov (United States)

    Smith, Stephen F [London, TN; Dress, William B [Camas, WA

    2010-02-09

    Systems and methods are described for hybrid spread spectrum radio systems. A method, includes receiving a hybrid spread spectrum signal including: fast frequency hopping demodulating and direct sequence demodulating a direct sequence spread spectrum signal, wherein multiple frequency hops occur within a single data-bit time and each bit is represented by chip transmissions at multiple frequencies.

  12. Fire spread in chaparral -"go or no-go?"

    Science.gov (United States)

    D.R. Weise; Xiangyang Zhou; Lulu Sun; Shankar Mahalingam

    2005-01-01

    Current fire models are designed to model the spread of a linear fire front in dead, small-diameter fuels. Fires in predominantly living vegetation account for a large proportion of annual burned area nationally. Prescribed burning is used to manage living fuels; however, prescribed burning is currently conducted under conditions that result in marginal burning. We do...

  13. Shower maximum detector for SDC calorimetry

    International Nuclear Information System (INIS)

    Ernwein, J.

    1994-01-01

    A prototype for the SDC end-cap (EM) calorimeter complete with a pre-shower and a shower maximum detector was tested in beams of electrons and Π's at CERN by an SDC subsystem group. The prototype was manufactured from scintillator tiles and strips read out with 1 mm diameter wave-length shifting fibers. The design and construction of the shower maximum detector is described, and results of laboratory tests on light yield and performance of the scintillator-fiber system are given. Preliminary results on energy and position measurements with the shower max detector in the test beam are shown. (authors). 4 refs., 5 figs

  14. Maximum likely scale estimation

    DEFF Research Database (Denmark)

    Loog, Marco; Pedersen, Kim Steenstrup; Markussen, Bo

    2005-01-01

    A maximum likelihood local scale estimation principle is presented. An actual implementation of the estimation principle uses second order moments of multiple measurements at a fixed location in the image. These measurements consist of Gaussian derivatives possibly taken at several scales and/or ...

  15. Robust Maximum Association Estimators

    NARCIS (Netherlands)

    A. Alfons (Andreas); C. Croux (Christophe); P. Filzmoser (Peter)

    2017-01-01

    textabstractThe maximum association between two multivariate variables X and Y is defined as the maximal value that a bivariate association measure between one-dimensional projections αX and αY can attain. Taking the Pearson correlation as projection index results in the first canonical correlation

  16. Edge Artifacts in Point Spread Function-based PET Reconstruction in Relation to Object Size and Reconstruction Parameters

    Directory of Open Access Journals (Sweden)

    Yuji Tsutsui

    2017-06-01

    Full Text Available Objective(s: We evaluated edge artifacts in relation to phantom diameter and reconstruction parameters in point spread function (PSF-based positron emission tomography (PET image reconstruction.Methods: PET data were acquired from an original cone-shaped phantom filled with 18F solution (21.9 kBq/mL for 10 min using a Biograph mCT scanner. The images were reconstructed using the baseline ordered subsets expectation maximization (OSEM algorithm and the OSEM with PSF correction model. The reconstruction parameters included a pixel size of 1.0, 2.0, or 3.0 mm, 1-12 iterations, 24 subsets, and a full width at half maximum (FWHM of the post-filter Gaussian filter of 1.0, 2.0, or 3.0 mm. We compared both the maximum recovery coefficient (RCmax and the mean recovery coefficient (RCmean in the phantom at different diameters.Results: The OSEM images had no edge artifacts, but the OSEM with PSF images had a dense edge delineating the hot phantom at diameters 10 mm or more and a dense spot at the center at diameters of 8 mm or less. The dense edge was clearly observed on images with a small pixel size, a Gaussian filter with a small FWHM, and a high number of iterations. At a phantom diameter of 6-7 mm, the RCmax for the OSEM and OSEM with PSF images was 60% and 140%, respectively (pixel size: 1.0 mm; FWHM of the Gaussian filter: 2.0 mm; iterations: 2. The RCmean of the OSEM with PSF images did not exceed 100%.Conclusion: PSF-based image reconstruction resulted in edge artifacts, the degree of which depends on the pixel size, number of iterations, FWHM of the Gaussian filter, and object size.

  17. Maximum power point tracking

    International Nuclear Information System (INIS)

    Enslin, J.H.R.

    1990-01-01

    A well engineered renewable remote energy system, utilizing the principal of Maximum Power Point Tracking can be m ore cost effective, has a higher reliability and can improve the quality of life in remote areas. This paper reports that a high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximum power point of the input source under varying input and output parameters. Maximum power point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of 15% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply systems. The advantages at larger temperature variations and larger power rated systems are much higher. Other advantages include optimal sizing and system monitor and control

  18. Spreading of rock avalanches

    Energy Technology Data Exchange (ETDEWEB)

    Kamis, A.S.; Savage, S.G. [McGill Univ., Dept. of Civil Engineering, Montreal, Quebec (Canada)

    1985-07-01

    Landslides and rockfalls that initiate on a steep slope eventually come to rest after flowing for some runout distance on a flat. Rockfalls of very large masses have been observed to exhibit unexpectedly long runout distances. This problem becomes more significant as the development of resources in mountain regions becomes more intensive. As early as 1881, Albert Heim observed and described the Elm rockfall of Switzerland (quoted by as HsU). This rockfall produced a debris which moved more than 2 Km along a nearly horizontal valley floor and one of its branches surged up the side of the valley to a height of 100 m. From the deposit of the Elm and the eyewitnesses Heim concluded that the debris behaved as a flowing fluid rather than sliding solids. Davies, among others, suggested that the excessive runout distance is volume dependent and the larger the volume of the debris, the longer the relative travel distance. A summary of the numerous hypotheses which have been proposed to explain this puzzling phenomena were also presented by Davies. However, none of these have been completely satisfactory or generally accepted. A simple model of the flow and spreading of a finite mass of cohesionless granular material down incline has been developed as a part of the present preliminary investigation into the mechanics of rockfalls. (author)

  19. Effects of Evaporation/Condensation on Spreading and Contact Angle of a Volatile Liquid Drop

    Science.gov (United States)

    Zhang, Nengli; Chao, David F.; Singh, Bhim S. (Technical Monitor)

    2000-01-01

    Effects of evaporation/condensation on spreading and contact angle were experimentally studied. A sessile drop of R-113 was tested at different vapor environments to determine the effects of evaporation/condensation on the evolution of contact diameter and contact angle of the drop. Condensation on the drop surface occurs at both the saturated and a nonsaturated vapor environments and promotes the spreading. When the drop is placed in the saturated vapor environment it tends to completely wetting and spreads rapidly. In a nonsaturated vapor environment, the evolution of the sessile drop is divided three stages: condensation-spreading stage, evaporation-retracting stage and rapid contracting stage. In the first stage the drop behaves as in the saturated environment. In the evaporation -retracting stage, the competition between spreading and evaporation of the drop determines the evolution characteristics of the contact diameter and the contact angle. A lower evaporation rate struggles against the spreading power to turn the drop from spreading to retracting with a continuous increase of the contact angle. The drop placed in open air has a much higher evaporation rate. The strong evaporation suppresses the spreading and accelerates the retraction of the drop with a linear decrease of the contact diameter. The contraction of the evaporating drops is gradually accelerated when the contact diameter decreases to 3 min and less till drying up, though the evaporation rate is gradually slowing down.

  20. Spreading Depression, Spreading Depolarizations, and the Cerebral Vasculature

    DEFF Research Database (Denmark)

    Ayata, Cenk; Lauritzen, Martin

    2015-01-01

    Spreading depression (SD) is a transient wave of near-complete neuronal and glial depolarization associated with massive transmembrane ionic and water shifts. It is evolutionarily conserved in the central nervous systems of a wide variety of species from locust to human. The depolarization spreads...

  1. Maximum entropy methods

    International Nuclear Information System (INIS)

    Ponman, T.J.

    1984-01-01

    For some years now two different expressions have been in use for maximum entropy image restoration and there has been some controversy over which one is appropriate for a given problem. Here two further entropies are presented and it is argued that there is no single correct algorithm. The properties of the four different methods are compared using simple 1D simulations with a view to showing how they can be used together to gain as much information as possible about the original object. (orig.)

  2. The last glacial maximum

    Science.gov (United States)

    Clark, P.U.; Dyke, A.S.; Shakun, J.D.; Carlson, A.E.; Clark, J.; Wohlfarth, B.; Mitrovica, J.X.; Hostetler, S.W.; McCabe, A.M.

    2009-01-01

    We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ???14.5 ka.

  3. 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)

  4. Heat transfer and fire spread

    Science.gov (United States)

    Hal E. Anderson

    1969-01-01

    Experimental testing of a mathematical model showed that radiant heat transfer accounted for no more than 40% of total heat flux required to maintain rate of spread. A reasonable prediction of spread was possible by assuming a horizontal convective heat transfer coefficient when certain fuel and flame characteristics were known. Fuel particle size had a linear relation...

  5. Information spreading dynamics in hypernetworks

    Science.gov (United States)

    Suo, Qi; Guo, Jin-Li; Shen, Ai-Zhong

    2018-04-01

    Contact pattern and spreading strategy fundamentally influence the spread of information. Current mathematical methods largely assume that contacts between individuals are fixed by networks. In fact, individuals are affected by all his/her neighbors in different social relationships. Here, we develop a mathematical approach to depict the information spreading process in hypernetworks. Each individual is viewed as a node, and each social relationship containing the individual is viewed as a hyperedge. Based on SIS epidemic model, we construct two spreading models. One model is based on global transmission, corresponding to RP strategy. The other is based on local transmission, corresponding to CP strategy. These models can degenerate into complex network models with a special parameter. Thus hypernetwork models extend the traditional models and are more realistic. Further, we discuss the impact of parameters including structure parameters of hypernetwork, spreading rate, recovering rate as well as information seed on the models. Propagation time and density of informed nodes can reveal the overall trend of information dissemination. Comparing these two models, we find out that there is no spreading threshold in RP, while there exists a spreading threshold in CP. The RP strategy induces a broader and faster information spreading process under the same parameters.

  6. Maximum Entropy Fundamentals

    Directory of Open Access Journals (Sweden)

    F. Topsøe

    2001-09-01

    Full Text Available Abstract: In its modern formulation, the Maximum Entropy Principle was promoted by E.T. Jaynes, starting in the mid-fifties. The principle dictates that one should look for a distribution, consistent with available information, which maximizes the entropy. However, this principle focuses only on distributions and it appears advantageous to bring information theoretical thinking more prominently into play by also focusing on the "observer" and on coding. This view was brought forward by the second named author in the late seventies and is the view we will follow-up on here. It leads to the consideration of a certain game, the Code Length Game and, via standard game theoretical thinking, to a principle of Game Theoretical Equilibrium. This principle is more basic than the Maximum Entropy Principle in the sense that the search for one type of optimal strategies in the Code Length Game translates directly into the search for distributions with maximum entropy. In the present paper we offer a self-contained and comprehensive treatment of fundamentals of both principles mentioned, based on a study of the Code Length Game. Though new concepts and results are presented, the reading should be instructional and accessible to a rather wide audience, at least if certain mathematical details are left aside at a rst reading. The most frequently studied instance of entropy maximization pertains to the Mean Energy Model which involves a moment constraint related to a given function, here taken to represent "energy". This type of application is very well known from the literature with hundreds of applications pertaining to several different elds and will also here serve as important illustration of the theory. But our approach reaches further, especially regarding the study of continuity properties of the entropy function, and this leads to new results which allow a discussion of models with so-called entropy loss. These results have tempted us to speculate over

  7. Probable maximum flood control

    International Nuclear Information System (INIS)

    DeGabriele, C.E.; Wu, C.L.

    1991-11-01

    This study proposes preliminary design concepts to protect the waste-handling facilities and all shaft and ramp entries to the underground from the probable maximum flood (PMF) in the current design configuration for the proposed Nevada Nuclear Waste Storage Investigation (NNWSI) repository protection provisions were furnished by the United States Bureau of Reclamation (USSR) or developed from USSR data. Proposed flood protection provisions include site grading, drainage channels, and diversion dikes. Figures are provided to show these proposed flood protection provisions at each area investigated. These areas are the central surface facilities (including the waste-handling building and waste treatment building), tuff ramp portal, waste ramp portal, men-and-materials shaft, emplacement exhaust shaft, and exploratory shafts facility

  8. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1988-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. We review the need for such methods in data analysis and show, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. We conclude with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  9. Solar maximum observatory

    International Nuclear Information System (INIS)

    Rust, D.M.

    1984-01-01

    The successful retrieval and repair of the Solar Maximum Mission (SMM) satellite by Shuttle astronauts in April 1984 permitted continuance of solar flare observations that began in 1980. The SMM carries a soft X ray polychromator, gamma ray, UV and hard X ray imaging spectrometers, a coronagraph/polarimeter and particle counters. The data gathered thus far indicated that electrical potentials of 25 MeV develop in flares within 2 sec of onset. X ray data show that flares are composed of compressed magnetic loops that have come too close together. Other data have been taken on mass ejection, impacts of electron beams and conduction fronts with the chromosphere and changes in the solar radiant flux due to sunspots. 13 references

  10. Introduction to maximum entropy

    International Nuclear Information System (INIS)

    Sivia, D.S.

    1989-01-01

    The maximum entropy (MaxEnt) principle has been successfully used in image reconstruction in a wide variety of fields. The author reviews the need for such methods in data analysis and shows, by use of a very simple example, why MaxEnt is to be preferred over other regularizing functions. This leads to a more general interpretation of the MaxEnt method, and its use is illustrated with several different examples. Practical difficulties with non-linear problems still remain, this being highlighted by the notorious phase problem in crystallography. He concludes with an example from neutron scattering, using data from a filter difference spectrometer to contrast MaxEnt with a conventional deconvolution. 12 refs., 8 figs., 1 tab

  11. Functional Maximum Autocorrelation Factors

    DEFF Research Database (Denmark)

    Larsen, Rasmus; Nielsen, Allan Aasbjerg

    2005-01-01

    MAF outperforms the functional PCA in concentrating the interesting' spectra/shape variation in one end of the eigenvalue spectrum and allows for easier interpretation of effects. Conclusions. Functional MAF analysis is a useful methods for extracting low dimensional models of temporally or spatially......Purpose. We aim at data where samples of an underlying function are observed in a spatial or temporal layout. Examples of underlying functions are reflectance spectra and biological shapes. We apply functional models based on smoothing splines and generalize the functional PCA in......\\verb+~+\\$\\backslash\\$cite{ramsay97} to functional maximum autocorrelation factors (MAF)\\verb+~+\\$\\backslash\\$cite{switzer85,larsen2001d}. We apply the method to biological shapes as well as reflectance spectra. {\\$\\backslash\\$bf Methods}. MAF seeks linear combination of the original variables that maximize autocorrelation between...

  12. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

    2015-01-01

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  13. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan

    2015-02-12

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  14. Determination of the Tapping Part Diameter of the Thread Mill

    Directory of Open Access Journals (Sweden)

    A. E. Dreval'

    2015-01-01

    Full Text Available Currently, there is a tendency to increase the proportion of thread milling operations, among other ways of tapping, which is associated with increasing number of CNC machines, flexibility and versatility of the process.Developments presently existing in the RF and used in the thread mills deal, mainly, with the thread milling cutter designs, to process internal and external thread with straight flutes made from high-speed steel.The paper presents a technique to calculate and select the initial design parameters, i.e. the external diameter of the tapping part of thread milling cutter, which is chosen as a basic computational design. The analysis of directories of tool companies containing foreign de-signs of solid thread end-milling cutters has shown that most of them rep-resent the thread cutter designs made of solid carbide. There are solid and interlocking side milling cutters, which use a tapping part both as a single-disk and as a multi-disk one; chip flutes are made to be both as direct and as screw; solid designs of cutters are made from carbide with a diameter of up to 20 ... 25 mm; thread cutters can be left- and right-hand cutting; Designs of the combined thread mills are proposed; internal channels are used for coolant supply.It is shown that the purpose of the external diameter of the tapping part of the thread mill should take into account the effect of the thread mill diameter on the milling process performance, precision of thread profile received, taper thread, tool strength, and the volume of flutes.The analysis has shown that when choosing the external diameter of the thread mill it worth taking its maximum diameter to improve the char-acteristics of the process under the restrictions imposed on the accuracy of the formed thread.

  15. Solar maximum mission

    International Nuclear Information System (INIS)

    Ryan, J.

    1981-01-01

    By understanding the sun, astrophysicists hope to expand this knowledge to understanding other stars. To study the sun, NASA launched a satellite on February 14, 1980. The project is named the Solar Maximum Mission (SMM). The satellite conducted detailed observations of the sun in collaboration with other satellites and ground-based optical and radio observations until its failure 10 months into the mission. The main objective of the SMM was to investigate one aspect of solar activity: solar flares. A brief description of the flare mechanism is given. The SMM satellite was valuable in providing information on where and how a solar flare occurs. A sequence of photographs of a solar flare taken from SMM satellite shows how a solar flare develops in a particular layer of the solar atmosphere. Two flares especially suitable for detailed observations by a joint effort occurred on April 30 and May 21 of 1980. These flares and observations of the flares are discussed. Also discussed are significant discoveries made by individual experiments

  16. 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...

  17. 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.

  18. 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.

  19. Rumor Spreading Model with Trust Mechanism in Complex Social Networks

    International Nuclear Information System (INIS)

    Wang Ya-Qi; Yang Xiao-Yuan; Han Yi-Liang; Wang Xu-An

    2013-01-01

    In this paper, to study rumor spreading, we propose a novel susceptible-infected-removed (SIR) model by introducing the trust mechanism. We derive mean-field equations that describe the dynamics of the SIR model on homogeneous networks and inhomogeneous networks. Then a steady-state analysis is conducted to investigate the critical threshold and the final size of the rumor spreading. We show that the introduction of trust mechanism reduces the final rumor size and the velocity of rumor spreading, but increases the critical thresholds on both networks. Moreover, the trust mechanism not only greatly reduces the maximum rumor influence, but also postpones the rumor terminal time, which provides us with more time to take measures to control the rumor spreading. The theoretical results are confirmed by sufficient numerical simulations. (interdisciplinary physics and related areas of science and technology)

  20. Rumor Spreading Model with Trust Mechanism in Complex Social Networks

    Science.gov (United States)

    Wang, Ya-Qi; Yang, Xiao-Yuan; Han, Yi-Liang; Wang, Xu-An

    2013-04-01

    In this paper, to study rumor spreading, we propose a novel susceptible-infected-removed (SIR) model by introducing the trust mechanism. We derive mean-field equations that describe the dynamics of the SIR model on homogeneous networks and inhomogeneous networks. Then a steady-state analysis is conducted to investigate the critical threshold and the final size of the rumor spreading. We show that the introduction of trust mechanism reduces the final rumor size and the velocity of rumor spreading, but increases the critical thresholds on both networks. Moreover, the trust mechanism not only greatly reduces the maximum rumor influence, but also postpones the rumor terminal time, which provides us with more time to take measures to control the rumor spreading. The theoretical results are confirmed by sufficient numerical simulations.

  1. Spreading gossip in social networks

    Science.gov (United States)

    Lind, Pedro G.; da Silva, Luciano R.; Andrade, José S., Jr.; Herrmann, Hans J.

    2007-09-01

    We study a simple model of information propagation in social networks, where two quantities are introduced: the spread factor, which measures the average maximal reachability of the neighbors of a given node that interchange information among each other, and the spreading time needed for the information to reach such a fraction of nodes. When the information refers to a particular node at which both quantities are measured, the model can be taken as a model for gossip propagation. In this context, we apply the model to real empirical networks of social acquaintances and compare the underlying spreading dynamics with different types of scale-free and small-world networks. We find that the number of friendship connections strongly influences the probability of being gossiped. Finally, we discuss how the spread factor is able to be applied to other situations.

  2. Spread effects - methodology; Spredningseffekter - metodegrunnlag

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2004-07-01

    Diffusion of technology, environmental effects and rebound effects are the principal effects from the funding of renewable energy and energy economising. It is difficult to estimate the impact of the spread effects both prior to the measures are implemented and after the measures are carried out. Statistical methods can be used to estimate the spread effects, but they are insecure and always need to be complemented with qualitative and subjective evaluations. It is more adequate to evaluate potential spread effects from market and market data surveillance for a selection of technologies and parties. Based on this information qualitative indicators for spread effects can be constructed and used both ex ante and ex post (ml)

  3. Spreading gossip in social networks.

    Science.gov (United States)

    Lind, Pedro G; da Silva, Luciano R; Andrade, José S; Herrmann, Hans J

    2007-09-01

    We study a simple model of information propagation in social networks, where two quantities are introduced: the spread factor, which measures the average maximal reachability of the neighbors of a given node that interchange information among each other, and the spreading time needed for the information to reach such a fraction of nodes. When the information refers to a particular node at which both quantities are measured, the model can be taken as a model for gossip propagation. In this context, we apply the model to real empirical networks of social acquaintances and compare the underlying spreading dynamics with different types of scale-free and small-world networks. We find that the number of friendship connections strongly influences the probability of being gossiped. Finally, we discuss how the spread factor is able to be applied to other situations.

  4. 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.

  5. Colonic motility and enema spreading

    International Nuclear Information System (INIS)

    Hardy, J.G.; Wood, E.; Clark, A.G.; Reynolds, J.R.; Queen's Medical Centre, Nottingham

    1986-01-01

    Radiolabelled enema solution was administered to eight healthy subjects, both in fasted and fed states. Enema spreading was monitored over a 4-h period using gamma scintigraphy and colonic motility was recorded simultaneously using a pressure sensitive radiotelemetry capsule. The rate and extent of enema dispersion were unaffected by eating. Spreading could be correlated with colonic motility and was inhibited by aboral propulsion of the colonic contents. (orig.)

  6. Piezoelectric ultrasonic micromotor with 1.5 mm diameter.

    Science.gov (United States)

    Dong, Shuxiang; Lim, Siak P; Lee, Kwork H; Zhang, Jingdong; Lim, Leong C; Uchino, Kenji

    2003-04-01

    A piezoelectric ultrasonic micromotor has been developed using a lead zirconate titanate (PZT) ceramic/metal composite tube stator that was 1.5 mm in diameter and 7 mm in length. The micromotor was operated in its first bending vibration mode (approximately 70 kHz), producing speeds from hundreds to over 2000 rpm in both rotational directions. The maximum torque-output was 45 microN-m, which is far superior to previous PZT thin film-based micromotors. This micromotor showed good reliability and stability for more than 300 hours of continued operation.

  7. VALUE CHANGE DIAMETERRED BLOOD CELLS ATHLETES IN THE PHYSICAL LOAD

    Directory of Open Access Journals (Sweden)

    Lidiya Yurevna Rubtsova

    2017-05-01

    Full Text Available Background: to study the nature of distribution of erythrocytes on diameter in the circulating blood of skiers-racers during achievement of a threshold of anaerobic threshold (AТ. Materials and methods: Professional Skiers racers (young men and men, girls and women at the age of 17–37 years (n = 33 are еxamined in the conditions of physical activity on the stationary bicycle. The research is conducted according to the protocol approved by local committee on bioethics in case of Institute of Physiology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences. Samples of blood were taken from an elbow vein on an empty stomach, then from finger capillaries to, - on a threshold of anaerobic exchange, after execution of loading “to the full” and in 5 min restoration. On the stained blood smears measured diameter of 50 erythrocytes. Results processed statistically with use of an application program package of Windows (Basic, 2011. Results: At stage AT at 36% of athletes defined increase in average diameter of erythrocytes from 7,46 ± 0,06 to 7,68 ± 0,08 µm (р<0,05, without changes at 12% (7,45 ± 0,04 – 7,43 ± 0,05 µm and reduction of the size of cells at 52% from 7,51± 0,04 to 7,35 ± 0,05 µm (р<0,05. In the conditions of a maximum load (men have 337,1 ± 12,4 W and women have 246,7 ± 10,8 W and during the 5-minute recovery diameter of erythrocytes returned to the original value. Conclusion: Thus, the individual nature of change of average diameter of erythrocytes at athletes is shown during achievement of ANSPs and probably corresponds to selective elimination preferentially macro- or microcytes.

  8. Stand diameter distribution modelling and prediction based on Richards function.

    Directory of Open Access Journals (Sweden)

    Ai-guo Duan

    Full Text Available The objective of this study was to introduce application of the Richards equation on modelling and prediction of stand diameter distribution. The long-term repeated measurement data sets, consisted of 309 diameter frequency distributions from Chinese fir (Cunninghamia lanceolata plantations in the southern China, were used. Also, 150 stands were used as fitting data, the other 159 stands were used for testing. Nonlinear regression method (NRM or maximum likelihood estimates method (MLEM were applied to estimate the parameters of models, and the parameter prediction method (PPM and parameter recovery method (PRM were used to predict the diameter distributions of unknown stands. Four main conclusions were obtained: (1 R distribution presented a more accurate simulation than three-parametric Weibull function; (2 the parameters p, q and r of R distribution proved to be its scale, location and shape parameters, and have a deep relationship with stand characteristics, which means the parameters of R distribution have good theoretical interpretation; (3 the ordinate of inflection point of R distribution has significant relativity with its skewness and kurtosis, and the fitted main distribution range for the cumulative diameter distribution of Chinese fir plantations was 0.4∼0.6; (4 the goodness-of-fit test showed diameter distributions of unknown stands can be well estimated by applying R distribution based on PRM or the combination of PPM and PRM under the condition that only quadratic mean DBH or plus stand age are known, and the non-rejection rates were near 80%, which are higher than the 72.33% non-rejection rate of three-parametric Weibull function based on the combination of PPM and PRM.

  9. 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.)

  10. SEX DETERMINATION FROM FEMORAL HEAD DIAMETERS IN ...

    African Journals Online (AJOL)

    hi-tech

    2000-03-01

    Mar 1, 2000 ... In medico-legal cases where sophisticated methods of sex determination is lacking, these ... scientific methods(3). Using the visual method ... between the sexes and the values of the right and left femoral head diameters.

  11. Effective diameters and corresponding states of fluids

    Science.gov (United States)

    Del Río, Fernando

    Effective hard-sphere diameters of fluids with purely repulsive interactions are derived from a generalized corresponding-states principle of Leland, Rowlinson and coworkers. Various alternative definitions are discussed and related. Virial expansions of the effective diameters and their corresponding volumes are obtained and compared with results of perturbation theory. Applications are made to inverse-power potentials, the repulsive part of the Lennard-Jones potential and hard spherocylinders and dumbells.

  12. 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.)

  13. 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

  14. 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.)

  15. Drop spreading and penetration into pre-wetted powders

    KAUST Repository

    Marston, Jeremy

    2013-05-01

    We present results from an experimental study of the impact of liquid drops onto powder beds which are pre-wetted with the impacting liquid. Using high-speed video imaging, we study both the dynamics of the initial spreading regime and drainage times once the drop has reached its maximum spread on the surface. During the initial spreading stage, we compare our experimental data to a previously developed model which incorporates imbibition into the spreading dynamics and observe reasonable agreement. We find that the maximum spread is a strong function of the moisture content in the powder bed and that the total time from impact to complete drainage is always shorter than that for dry powder. Our results indicate that there is an optimum moisture content (or saturation) which leads to the fastest penetration. We use simple scaling arguments which also identify an optimum moisture content for fastest penetration, which agrees very well with the experimental result. © 2013 Elsevier B.V.

  16. Seasonal spreading of the Persian Gulf water mass in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Prasad, T.G.; Ikeda, M.; PrasannaKumar, S.

    The characteristics of the subsurface salinity maximum associated with the Persian Gulf Water mass (PGW) are used to quantify the spreading and mixing of PGW in the thermocline of the Arabian Sea based on a bimonthly climatology of temperature...

  17. New PN Even Balanced Sequences for Spread-Spectrum Systems

    Directory of Open Access Journals (Sweden)

    Inácio JAL

    2005-01-01

    Full Text Available A new class of pseudonoise even balanced (PN-EB binary spreading sequences is derived from existing classical odd-length families of maximum-length sequences, such as those proposed by Gold, by appending or inserting one extra-zero element (chip to the original sequences. The incentive to generate large families of PN-EB spreading sequences is motivated by analyzing the spreading effect of these sequences from a natural sampling point of view. From this analysis a new definition for PG is established, from which it becomes clear that very high processing gains (PGs can be achieved in band-limited direct-sequence spread-spectrum (DSSS applications by using spreading sequences with zero mean, given that certain conditions regarding spectral aliasing are met. To obtain large families of even balanced (i.e., equal number of ones and zeros sequences, two design criteria are proposed, namely the ranging criterion (RC and the generating ranging criterion (GRC. PN-EB sequences in the polynomial range are derived using these criteria, and it is shown that they exhibit secondary autocorrelation and cross-correlation peaks comparable to the sequences they are derived from. The methods proposed not only facilitate the generation of large numbers of new PN-EB spreading sequences required for CDMA applications, but simultaneously offer high processing gains and good despreading characteristics in multiuser SS scenarios with band-limited noise and interference spectra. Simulation results are presented to confirm the respective claims made.

  18. 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

  19. Spreading dynamics in complex networks

    Science.gov (United States)

    Pei, Sen; Makse, Hernán A.

    2013-12-01

    Searching for influential spreaders in complex networks is an issue of great significance for applications across various domains, ranging from epidemic control, innovation diffusion, viral marketing, and social movement to idea propagation. In this paper, we first display some of the most important theoretical models that describe spreading processes, and then discuss the problem of locating both the individual and multiple influential spreaders respectively. Recent approaches in these two topics are presented. For the identification of privileged single spreaders, we summarize several widely used centralities, such as degree, betweenness centrality, PageRank, k-shell, etc. We investigate the empirical diffusion data in a large scale online social community—LiveJournal. With this extensive dataset, we find that various measures can convey very distinct information of nodes. Of all the users in the LiveJournal social network, only a small fraction of them are involved in spreading. For the spreading processes in LiveJournal, while degree can locate nodes participating in information diffusion with higher probability, k-shell is more effective in finding nodes with a large influence. Our results should provide useful information for designing efficient spreading strategies in reality.

  20. Spreading dynamics in complex networks

    International Nuclear Information System (INIS)

    Pei, Sen; Makse, Hernán A

    2013-01-01

    Searching for influential spreaders in complex networks is an issue of great significance for applications across various domains, ranging from epidemic control, innovation diffusion, viral marketing, and social movement to idea propagation. In this paper, we first display some of the most important theoretical models that describe spreading processes, and then discuss the problem of locating both the individual and multiple influential spreaders respectively. Recent approaches in these two topics are presented. For the identification of privileged single spreaders, we summarize several widely used centralities, such as degree, betweenness centrality, PageRank, k-shell, etc. We investigate the empirical diffusion data in a large scale online social community—LiveJournal. With this extensive dataset, we find that various measures can convey very distinct information of nodes. Of all the users in the LiveJournal social network, only a small fraction of them are involved in spreading. For the spreading processes in LiveJournal, while degree can locate nodes participating in information diffusion with higher probability, k-shell is more effective in finding nodes with a large influence. Our results should provide useful information for designing efficient spreading strategies in reality. (paper)

  1. Dual polarized, heat spreading rectenna

    Science.gov (United States)

    Epp, Larry W. (Inventor); Khan, Abdur R. (Inventor); Smith, R. Peter (Inventor); Smith, Hugh K. (Inventor)

    1999-01-01

    An aperture coupled patch splits energy from two different polarization components to different locations to spread heat. In addition, there is no physical electrical connection between the slot, patch and circuitry. The circuitry is located under a ground plane which shields against harmonic radiation back to the RF source.

  2. 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)

  3. Assessment of lymph node tumour from CT scans: how good is diameter and visual assessment

    International Nuclear Information System (INIS)

    Kumar, Pratik; Rehani, M.M.; Anand, Vikram; Raina, Vinod; Rao, Keshava

    1995-01-01

    The evaluation response of tumours requires quantification of tumour mass in terms of volume or maximum diameter. In normal practice changes in maximum diameter of tumour are assessed visually on follow-up CT films. This may lead to erroneous results. Twenty one patients of testicular cancer in stage II A to II D with retroperitoneal lymphadenopathy were scanned by CT for 3 to 5 times during the course of treatment. Tumour size was assessed in terms of diameter as per practice followed routinely. A very important observation was that actual measurement of diameter instead of visual assessment resulted in change of stage of cancer in 42.8% (9 out of 21) cases. Moreover, in 6 out of these 21 cases (28%) there occurred a change in stage from II C to II D which assumes significance due to change in treatment protocol from BEP (Bleomycin, Etoposide, Cisplatinum) to BOP-VIP (Bleomycin, Vincristin, Cisplatinum , VP-16, Ifosfamide, Cisplatinum). Tumour volume estimated on the basis of visual method differed considerably from the calculated one. In 16 out of 21 scans, the difference was between 6.4% to 42.9%. The acceptable difference of 5% was seen only in 4 out of 21 cases indicating the importance of volume measurement. The method of volume estimation was validated and found to be within ± 5% of actual volume. The correlation between diameter and volume shows that tumours with similar range of diameter have 20% to 100% more volume. Many times increase in diameter was found associated with actually reduced tumour volume, difference being as much as 515%. This has not been documented earlier in clinical situations. Thus, the study underscores the role of measuring the diameter of tumour for staging and highlights the need for actual volume estimation rather than depending on maximum transverse diameter alone in follow-up studies. (author). 9 refs., 4 figs., 4 tabs

  4. 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

  5. Simultaneous spreading and evaporation: recent developments.

    Science.gov (United States)

    Semenov, Sergey; Trybala, Anna; Rubio, Ramon G; Kovalchuk, Nina; Starov, Victor; Velarde, Manuel G

    2014-04-01

    The recent progress in theoretical and experimental studies of simultaneous spreading and evaporation of liquid droplets on solid substrates is discussed for pure liquids including nanodroplets, nanosuspensions of inorganic particles (nanofluids) and surfactant solutions. Evaporation of both complete wetting and partial wetting liquids into a nonsaturated vapour atmosphere are considered. However, the main attention is paid to the case of partial wetting when the hysteresis of static contact angle takes place. In the case of complete wetting the spreading/evaporation process proceeds in two stages. A theory was suggested for this case and a good agreement with available experimental data was achieved. In the case of partial wetting the spreading/evaporation of a sessile droplet of pure liquid goes through four subsequent stages: (i) the initial stage, spreading, is relatively short (1-2 min) and therefore evaporation can be neglected during this stage; during the initial stage the contact angle reaches the value of advancing contact angle and the radius of the droplet base reaches its maximum value, (ii) the first stage of evaporation is characterised by the constant value of the radius of the droplet base; the value of the contact angle during the first stage decreases from static advancing to static receding contact angle; (iii) during the second stage of evaporation the contact angle remains constant and equal to its receding value, while the radius of the droplet base decreases; and (iv) at the third stage of evaporation both the contact angle and the radius of the droplet base decrease until the drop completely disappears. It has been shown theoretically and confirmed experimentally that during the first and second stages of evaporation the volume of droplet to power 2/3 decreases linearly with time. The universal dependence of the contact angle during the first stage and of the radius of the droplet base during the second stage on the reduced time has been

  6. Credal Networks under Maximum Entropy

    OpenAIRE

    Lukasiewicz, Thomas

    2013-01-01

    We apply the principle of maximum entropy to select a unique joint probability distribution from the set of all joint probability distributions specified by a credal network. In detail, we start by showing that the unique joint distribution of a Bayesian tree coincides with the maximum entropy model of its conditional distributions. This result, however, does not hold anymore for general Bayesian networks. We thus present a new kind of maximum entropy models, which are computed sequentially. ...

  7. Wiener Index, Diameter, and Stretch Factor of a Weighted Planar Graph in Subquadratic Time

    DEFF Research Database (Denmark)

    Wulff-Nilsen, Christian

    over all pairs of distinct vertices of the ratio between the graph distance and the Euclidean distance between the two vertices). More specifically, we show that the Wiener index and diameter can be found in O(n^2*(log log n)^4/log n) worst-case time and that the stretch factor can be found in O(n^2......We solve three open problems: the existence of subquadratic time algorithms for computing the Wiener index (sum of APSP distances) and the diameter (maximum distance between any vertex pair) of a planar graph with non-negative edge weights and the stretch factor of a plane geometric graph (maximum...

  8. Hair root diameter measurement as an indicator of protein deficiency in nonhospitalized alcoholics.

    Science.gov (United States)

    Bregar, R R; Gordon, M; Whitney, E N

    1978-02-01

    Protein status of alcoholics admitted to a detoxification center was investigated with a view to adapting a hair root test for use in screening for protein deficiency. Hair root volume and hair root diameter had previously been shown to correlate well with hair root protein and to be sensitive indicators of protein deficiency. Hair root volumes in this study correlated well with mean maximum hair root diameters (n = 35, r = 0.9), which were simpler to measure, so diameter measurements were used. Mean maximum hair root diameters (range 0.02 to 0.19 mm) correlated with plasma RNase concentrations (range 6000 to 14,000 units/ml; n = 17, r = -0.7). Mean hair diameters of 84 alcoholics averaged 0.0864 +/- 0.0366 mm; those of 25 nonalcoholics were significantly greater: 0.100 +/- 0.0254 mm (P less than 0.05). Frequency of occurrence of hair root diameters of 0.06 mm or less was significantly higher in 71 alcoholics (29.5%) than in 23 nonalcoholics (8.6%) matched by age. Mean hair root diameters of 0.06 mm or less therefore can be used to signify protein deficiency where more expensive or technically demanding tests are not feasible. Protein deficiency occurs extensively in non hospitalized alcoholics. This method enables staff to single out those clients most likely to be in need of nutritional counseling and therapy.

  9. Small diameter symmetric networks from linear groups

    Science.gov (United States)

    Campbell, Lowell; Carlsson, Gunnar E.; Dinneen, Michael J.; Faber, Vance; Fellows, Michael R.; Langston, Michael A.; Moore, James W.; Multihaupt, Andrew P.; Sexton, Harlan B.

    1992-01-01

    In this note is reported a collection of constructions of symmetric networks that provide the largest known values for the number of nodes that can be placed in a network of a given degree and diameter. Some of the constructions are in the range of current potential engineering significance. The constructions are Cayley graphs of linear groups obtained by experimental computation.

  10. Changing the Diameter of a Viewing Tube

    Science.gov (United States)

    Obara, Samuel

    2009-01-01

    This article is about the students' investigation about the relationship between the diameter of the view tubes (x) of constant lengths and the viewable vertical distance (y) on the wall while keeping the perpendicular distance from the eyeball to the wall constant. The students collected data and used and represented it in tabular and graphical…

  11. Height - Diameter predictive equations for Rubber (Hevea ...

    African Journals Online (AJOL)

    BUKOLA

    They proffer logistic data for modeling and futuristic prediction for sustainable forest management. Diameter is one of the most ... in various quantitative estimation following the intricacy of time, availability of modern equipments .... growth functions. This trend is shown in Figure 1 where the prediction equations are plotted.

  12. Benefits of Two Turbine Rotor Diameters and Hub Heights in the Same Wind Farm

    Energy Technology Data Exchange (ETDEWEB)

    Dykes, Katherine L [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Stanley, Andrew P. J. [Brigham Young University; Ning, Andrew [Brigham Young University

    2018-01-12

    Significant turbine-wake interactions greatly reduce power output in a wind farm. If different turbine hub heights and rotor diameters are included in the same wind farm, the wake interference in the farm will be reduced, resulting in a lower cost of energy (COE) than a farm with identical turbines. In this paper, we present a method to model wind farm COE in farms with hub heights and rotor diameters that vary across the wind farm. We also demonstrate how to optimize these wind farms to minimize COE. The results show that COE can be greatly reduced in wind farms with non-homogeneous turbines, especially when the turbines are spaced close together. For a unidirectional wind rose, including different turbine design in the wind farm has a similar decrease in COE to spreading the wind turbines farther apart. When the rotor diameter and hub height of the wind turbines in a farm are optimized uniformly, a COE decrease of 4% to 13% (depending on the grid spacing and wind shear exponent) is achieved compared to the baseline. When the rotor diameter and turbine heights are optimized non-uniformly, with two different diameters and heights throughout the farm, there is a COE decrease of 22% to 41% compared to the baseline. For a more spread wind rose with a dominant probability from the west, there is a COE decrease between 3% and 10% for uniformly optimized rotor diameter and height compared to the baseline. With two optimized rotor diameters and heights through the farm, a COE decrease of 3% to 19% is achieved. For a similar wind rose shifted such that the dominant wind direction is from the northwest, a COE decrease between 3% and 10% results from uniformly optimized wind turbines compared to the baseline. A COE decrease of 3% to 17% compared to the baseline occurs with two different turbines are optimized throughout the wind farm.

  13. Spreading of a granular droplet

    Science.gov (United States)

    Clement, Eric; Sanchez, Ivan; Raynaud, Franck; Lanuza, Jose; Andreotti, Bruno; Aranson, Igor

    2008-03-01

    The influence of controlled vibrations on the granular rheology is investigated in a specifically designed experiment in which a granular film spreads under the action of horizontal vibrations. A nonlinear diffusion equation is derived theoretically that describes the evolution of the deposit shape. A self-similar parabolic shape (the``granular droplet'') and a spreading dynamics are predicted that both agree quantitatively with the experimental results. The theoretical analysis is used to extract effective friction coefficients between the base and the granular layer under sustained and controlled vibrations. A shear thickening regime characteristic of dense granular flows is evidenced at low vibration energy, both for glass beads and natural sand. Conversely, shear thinning is observed at high agitation.

  14. Validating automated kidney stone volumetry in computed tomography and mathematical correlation with estimated stone volume based on diameter.

    Science.gov (United States)

    Wilhelm, Konrad; Miernik, Arkadiusz; Hein, Simon; Schlager, Daniel; Adams, Fabian; Benndorf, Matthias; Fritz, Benjamin; Langer, Mathias; Hesse, Albrecht; Schoenthaler, Martin; Neubauer, Jakob

    2018-06-02

    To validate AutoMated UroLithiasis Evaluation Tool (AMULET) software for kidney stone volumetry and compare its performance to standard clinical practice. Maximum diameter and volume of 96 urinary stones were measured as reference standard by three independent urologists. The same stones were positioned in an anthropomorphic phantom and CT scans acquired in standard settings. Three independent radiologists blinded to the reference values took manual measurements of the maximum diameter and automatic measurements of maximum diameter and volume. An "expected volume" was calculated based on manual diameter measurements using the formula: V=4/3 πr³. 96 stones were analyzed in the study. We had initially aimed to assess 100. Nine were replaced during data acquisition due of crumbling and 4 had to be excluded because the automated measurement did not work. Mean reference maximum diameter was 13.3 mm (5.2-32.1 mm). Correlation coefficients among all measured outcomes were compared. The correlation between the manual and automatic diameter measurements to the reference was 0.98 and 0.91, respectively (pvolumetry is possible and significantly more accurate than diameter-based volumetric calculations. To avoid bias in clinical trials, size should be measured as volume. However, automated diameter measurements are not as accurate as manual measurements.

  15. 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.).

  16. Drop Spreading with Random Viscosity

    Science.gov (United States)

    Xu, Feng; Jensen, Oliver

    2016-11-01

    Airway mucus acts as a barrier to protect the lung. However as a biological material, its physical properties are known imperfectly and can be spatially heterogeneous. In this study we assess the impact of these uncertainties on the rate of spreading of a drop (representing an inhaled aerosol) over a mucus film. We model the film as Newtonian, having a viscosity that depends linearly on the concentration of a passive solute (a crude proxy for mucin proteins). Given an initial random solute (and hence viscosity) distribution, described as a Gaussian random field with a given correlation structure, we seek to quantify the uncertainties in outcomes as the drop spreads. Using lubrication theory, we describe the spreading of the drop in terms of a system of coupled nonlinear PDEs governing the evolution of film height and the vertically-averaged solute concentration. We perform Monte Carlo simulations to predict the variability in the drop centre location and width (1D) or area (2D). We show how simulation results are well described (at much lower computational cost) by a low-order model using a weak disorder expansion. Our results show for example how variability in the drop location is a non-monotonic function of the solute correlation length increases. Engineering and Physical Sciences Research Council.

  17. Slip of Spreading Viscoplastic Droplets.

    Science.gov (United States)

    Jalaal, Maziyar; Balmforth, Neil J; Stoeber, Boris

    2015-11-10

    The spreading of axisymmetric viscoplastic droplets extruded slowly on glass surfaces is studied experimentally using shadowgraphy and swept-field confocal microscopy. The microscopy furnishes vertical profiles of the radial velocity using particle image velocimetry (PIV) with neutrally buoyant tracers seeded in the fluid. Experiments were conducted for two complex fluids: aqueous solutions of Carbopol and xanthan gum. On untreated glass surfaces, PIV demonstrates that both fluids experience a significant amount of effective slip. The experiments were repeated on glass that had been treated to feature positive surface charges, thereby promoting adhesion between the negatively charged polymeric constituents of the fluids and the glass surface. The Carbopol and xanthan gum droplets spread more slowly on the treated surface and to a smaller radial distance. PIV demonstrated that this reduced spreading was associated with a substantial reduction in slip. For Carbopol, the effective slip could be eliminated entirely to within the precision of the PIV measurements; the reduction in slip was less effective for xanthan gum, with a weak slip velocity remaining noticeable.

  18. The relationship between diameter and taper of nickel-titanium rotary instruments on the torsional resistance to fracture

    Directory of Open Access Journals (Sweden)

    Erick Miranda Souza

    Full Text Available Objective: To evaluate the resistance to fracture of rotary Ni-Ti files of various diameters and tapers after torsional stress simulation. Methods: Profile (Dentsply Maillerfer, Ballaigues, Suíça instruments sizes 15 to 40, taper 0.04 and 0.06 were used. Ten instruments of each size and taper were tested, totaling 120 files. The maximum torque (Tmax until fracture was determined in accordance with the ANSI / ADA Protocol Nº 28 . The maximum force was converted into maximum torque using the formula: Tmax = Loadmax x RadiusResults: The diameter (p<0.001 and taper (p<0.001 influenced the maximum torque to fracture. With the increase in diameter and taperthere was a gradual increase in the maximum torque. Using the multiple regression method an equation relating the maximum torque to the diameter (D and the taper (T was found: Tmax = -1.4 + 0.08D + 10.5T. Conclusion: The increase in diameter and taper promoted an increase in resistance to torsion. The variation of the taper from 0.04 to 0.06 in instruments with the same diameter increased resistance to fracture by torsion by around 25%.

  19. An empirical model of global spread-f occurrence

    International Nuclear Information System (INIS)

    Singleton, D.G.

    1974-09-01

    A method of combining models of ionospheric F-layer peak electron density and irregularity incremental electron density into a model of the occurrence probability of the frequency spreading component of spread-F is presented. The predictions of the model are compared with spread-F occurrence data obtained under sunspot maximum conditions. Good agreement is obtained for latitudes less than 70 0 geomagnetic. At higher latitudes, the inclusion of a 'blackout factor' in the model allows it to accurately represent the data and, in so doing, resolves an apparent discrepancy in the occurrence statistics at high latitudes. The blackout factor is ascribed to the effect of polar blackout on the spread-F statistics and/or the lack of a definitve incremental electron density model for irregularities at polar latitudes. Ways of isolating these effects and assessing their relative importance in the blackout factor are discussed. The model, besides providing estimates of spread-F occurrence on a worldwide basis, which will be of value in the engineering of HF and VHF communications, also furnishes a means of further checking the irregularity incremental electron density model on which it is based. (author)

  20. Device for guiding various diameter size cable

    Energy Technology Data Exchange (ETDEWEB)

    Litvinov, I.M.; Klauzer, L.P.; Yeganov, L.I.; Zaripov, A.M.

    1982-01-30

    A design is submitted for a device to guide cable of various diameters. This device consists of a profiled multiple-pass roller, and clamps for uniting cut cable. This design is simplified by allowing both the rollers and their supports to rotate on the roller axis thus facilitating interaction with the clamps. The working surface of the supports is evolute while the outside surfaces have screw-channels for transfering the cable from one roller pass to the other.

  1. Reverse preferential spread in complex networks

    Science.gov (United States)

    Toyoizumi, Hiroshi; Tani, Seiichi; Miyoshi, Naoto; Okamoto, Yoshio

    2012-08-01

    Large-degree nodes may have a larger influence on the network, but they can be bottlenecks for spreading information since spreading attempts tend to concentrate on these nodes and become redundant. We discuss that the reverse preferential spread (distributing information inversely proportional to the degree of the receiving node) has an advantage over other spread mechanisms. In large uncorrelated networks, we show that the mean number of nodes that receive information under the reverse preferential spread is an upper bound among any other weight-based spread mechanisms, and this upper bound is indeed a logistic growth independent of the degree distribution.

  2. Stocking and structure for maximum growth in sugar maple selection stands.

    Science.gov (United States)

    Thomas R. Crow; Carl H. Tubbs; Rodney D. Jacobs; Robert R. Oberg

    1981-01-01

    The impacts of stocking, structure, and cutting cycle on basal area, cubic foot volume, board foot volume, and diameter growth are considered. Recommendations are provided for maximum growth in uneven-aged sugar maple stands.

  3. 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.

  4. Plume spread and atmospheric stability

    Energy Technology Data Exchange (ETDEWEB)

    Weber, R O [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1999-08-01

    The horizontal spread of a plume in atmospheric dispersion can be described by the standard deviation of horizontal direction. The widely used Pasquill-Gifford classes of atmospheric stability have assigned typical values of the standard deviation of horizontal wind direction and of the lapse rate. A measured lapse rate can thus be used to estimate the standard deviation of wind direction. It is examined by means of a large dataset of fast wind measurements how good these estimates are. (author) 1 fig., 2 refs.

  5. Epidemic spreading on interconnected networks.

    Science.gov (United States)

    Saumell-Mendiola, Anna; Serrano, M Ángeles; Boguñá, Marián

    2012-08-01

    Many real networks are not isolated from each other but form networks of networks, often interrelated in nontrivial ways. Here, we analyze an epidemic spreading process taking place on top of two interconnected complex networks. We develop a heterogeneous mean-field approach that allows us to calculate the conditions for the emergence of an endemic state. Interestingly, a global endemic state may arise in the coupled system even though the epidemics is not able to propagate on each network separately and even when the number of coupling connections is small. Our analytic results are successfully confronted against large-scale numerical simulations.

  6. Spread of cochlear excitation during stimulation with pulsed infrared radiation: inferior colliculus measurements

    Science.gov (United States)

    Richter, C.-P.; Rajguru, S. M.; Matic, A. I.; Moreno, E. L.; Fishman, A. J.; Robinson, A. M.; Suh, E.; Walsh, J. T., Jr.

    2011-10-01

    Infrared neural stimulation (INS) has received considerable attention over the last few years. It provides an alternative method to artificially stimulate neurons without electrical current or the introduction of exogenous chromophores. One of the primary benefits of INS could be the improved spatial selectivity when compared with electrical stimulation. In the present study, we have evaluated the spatial selectivity of INS in the acutely damaged cochlea of guinea pigs and compared it to stimulation with acoustic tone pips in normal-hearing animals. The radiation was delivered via a 200 µm diameter optical fiber, which was inserted through a cochleostomy into the scala tympani of the basal cochlear turn. The stimulated section along the cochlear spiral ganglion was estimated from the neural responses recorded from the central nucleus of the inferior colliculus (ICC). ICC responses were recorded in response to cochlear INS using a multichannel penetrating electrode array. Spatial tuning curves (STCs) were constructed from the responses. For INS, approximately 55% of the activation profiles showed a single maximum, ~22% had two maxima and ~13% had multiple maxima. The remaining 10% of the profiles occurred at the limits of the electrode array and could not be classified. The majority of ICC STCs indicated that the spread of activation evoked by optical stimuli is comparable to that produced by acoustic tone pips.

  7. Coding-Spreading Tradeoff in CDMA Systems

    National Research Council Canada - National Science Library

    Bolas, Eduardo

    2002-01-01

    .... Comparing different combinations of coding and spreading with a traditional DS-CDMA, as defined in the IS-95 standard, allows the criteria to be defined for the best coding-spreading tradeoff in CDMA systems...

  8. Lexical Ambiguity: Making a Case against Spread

    Science.gov (United States)

    Kaplan, Jennifer J.; Rogness, Neal T.; Fisher, Diane G.

    2012-01-01

    We argue for decreasing the use of the word "spread" when describing the statistical idea of dispersion or variability in introductory statistics courses. In addition, we argue for increasing the use of the word "variability" as a replacement for "spread."

  9. Maximum Entropy in Drug Discovery

    Directory of Open Access Journals (Sweden)

    Chih-Yuan Tseng

    2014-07-01

    Full Text Available Drug discovery applies multidisciplinary approaches either experimentally, computationally or both ways to identify lead compounds to treat various diseases. While conventional approaches have yielded many US Food and Drug Administration (FDA-approved drugs, researchers continue investigating and designing better approaches to increase the success rate in the discovery process. In this article, we provide an overview of the current strategies and point out where and how the method of maximum entropy has been introduced in this area. The maximum entropy principle has its root in thermodynamics, yet since Jaynes’ pioneering work in the 1950s, the maximum entropy principle has not only been used as a physics law, but also as a reasoning tool that allows us to process information in hand with the least bias. Its applicability in various disciplines has been abundantly demonstrated. We give several examples of applications of maximum entropy in different stages of drug discovery. Finally, we discuss a promising new direction in drug discovery that is likely to hinge on the ways of utilizing maximum entropy.

  10. Diameter-dependent hydrophobicity in carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Kyakuno, Haruka, E-mail: h-kyakuno@kanagawa-u.ac.jp [Department of Physics, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Institute of Physics, Faculty of Engineering, Kanagawa University, Yokohama 221-8686 (Japan); Fukasawa, Mamoru; Ichimura, Ryota; Nakai, Yusuke; Maniwa, Yutaka, E-mail: maniwa@phys.se.tmu.ac.jp [Department of Physics, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); Matsuda, Kazuyuki [Institute of Physics, Faculty of Engineering, Kanagawa University, Yokohama 221-8686 (Japan); Miyata, Yasumitsu [Department of Physics, Graduate School of Science and Engineering, Tokyo Metropolitan University, Hachioji 192-0397 (Japan); PRESTO, JST, Kawaguchi 332-0012 (Japan); Saito, Takeshi [Nanotube Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba 305-8565 (Japan)

    2016-08-14

    Single-wall carbon nanotubes (SWCNTs) are a good model system that provides atomically smooth nanocavities. It has been reported that water-SWCNTs exhibit hydrophobicity depending on the temperature T and the SWCNT diameter D. SWCNTs adsorb water molecules spontaneously in their cylindrical pores around room temperature, whereas they exhibit a hydrophilic-hydrophobic transition or wet-dry transition (WDT) at a critical temperature T{sub wd} ≈ 220-230 K and above a critical diameter D{sub c} ≈ 1.4-1.6 nm. However, details of the WDT phenomenon and its mechanism remain unknown. Here, we report a systematic experimental study involving X-ray diffraction, optical microscopy, and differential scanning calorimetry. It is found that water molecules inside thick SWCNTs (D > D{sub c}) evaporate and condense into ice Ih outside the SWCNTs at T{sub wd} upon cooling, and the ice Ih evaporates and condenses inside the SWCNTs upon heating. On the other hand, residual water trapped inside the SWCNTs below T{sub wd} freezes. Molecular dynamics simulations indicate that upon lowering T, the hydrophobicity of thick SWCNTs increases without any structural transition, while the water inside thin SWCNTs (D < D{sub c}) exhibits a structural transition, forming an ordered ice. This ice has a well-developed hydrogen bonding network adapting to the cylindrical pores of the SWCNTs. Thus, the unusual diameter dependence of the WDT is attributed to the adaptability of the structure of water to the pore dimension and shape.

  11. Retrobulbar diameter of optic nerve in glaucoma

    Directory of Open Access Journals (Sweden)

    Stefanović Ivan

    2009-01-01

    Full Text Available Introduction. The ultrasound diagnostics of the optic nerve includes the analysis of the optic nerve disc (PNO and measuring of its retrobulbar diameter. With B-scan, by Schraeder's method, it is possible to measure very precisely the optic nerve, the pial diameter, the normal values for the pial diameter being 2.8-4.1 mm. In glaucoma, the disease that is most frequently associated with higher intraocular pressure, there comes the destruction of nerve fibres, which can be visualized as the excavation of the optic nerve disc. Objective. In this paper, we were interested in finding whether in glaucoma, and in what phase of the disease, the optic nerve starts growing thinner. Aware of many forms of this very complex disease, we were interested in knowing if the visualization of excavation on the optic nerve disc is related to diminishing of the pial diameter of the retrobulbar nerve part. Methods. There were treated the patients who had already had the diagnosis of glaucoma and the visualized excavation of the optic disc of various dimensions. Echographically, there was measured the thickness of the retrobulbar part of the optic nerve and the finding compared in relation to the excavation of the optic disc. Results. In all eyes with glaucoma, a normal size of the retrobulbar part of the optic nerve was measured, ranging from 3.01 to 3.91 mm with the median of 3.36 mm. Also, by testing the correlation between the thickness of the optic nerve and the excavation of the PNO, by Pearson test, we found that there was no correlation between these two parameters (r=0.109; p>0.05. Conclusion. In the patients with glaucoma, the retrobulbar part of the optic nerve is not thinner (it has normal values, even not in the cases with a totally excavated optic disc. There is no connection between the size of the PNO excavation and the thickness of the retrobulbar part of the optic nerve.

  12. 29 mm Diameter Target Test Report

    Energy Technology Data Exchange (ETDEWEB)

    Woloshun, Keith Albert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Olivas, Eric Richard [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dale, Gregory E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Naranjo, Angela Carol [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Romero, Frank Patrick [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Chemerisov, Sergey [Argonne National Lab. (ANL), Argonne, IL (United States); Gromov, Roman [Argonne National Lab. (ANL), Argonne, IL (United States)

    2017-10-23

    After numerous delays, the test of the 29 mm diameter target was conducted on 8/18/2017. The complete target design report, dated 8/15/2016, is reproduced below for completeness. This describes in detail the 10 disk target with varying thickness disks. The report presents and discusses the test results. In brief summary, there appears to have been multiple instrumentation errors. Measured temperatures, pressures and IR camera window temperature measurement are all suspect. All tests were done at 35 MeV, with 171 μA current, or 6 kW of beam power.

  13. Estimation of the diameter-charge distribution in polydisperse electrically charged sprays of electrically insulating liquids

    Science.gov (United States)

    Rigit, A. R. H.; Shrimpton, John S.

    2009-06-01

    The majority of scientific and industrial electrical spray applications make use of sprays that contain a range of drop diameters. Indirect evidence suggests the mean drop diameter and the mean drop charge level are usually correlated. In addition, within each drop diameter class there is every reason to suspect a distribution of charge levels exist for a particular drop diameter class. This paper presents an experimental method that uses the joint PDF of drop velocity and diameter, obtained from phase Doppler anemometry measurements, and directly obtained spatially resolved distributions of the mass and charge flux to obtain a drop diameter and charge frequency distribution. The method is demonstrated using several data-sets obtained from experimental measurements of steady poly-disperse sprays of an electrically insulating liquid produced with the charge injection technique. The space charge repulsion in the spray plume produces a hollow cone spray structure. In addition an approximate self-similarity is observed, with the maximum radial mass and charge flow occurring at r/ d ~ 200. The charge flux profile is slightly offset from the mass flux profile, and this gives direct evidence that the spray specific charge increases from approximately 20% of the bulk mean spray specific charge on the spray axis to approximately 200% of the bulk mean specific charge in the periphery of the spray. The results from the drop charge estimation model suggest a complex picture of the correlation between drop charge and drop diameter, with spray specific charge, injection velocity and orifice diameter all contributing to the shape of the drop diameter-charge distribution. Mean drop charge as a function of the Rayleigh limit is approximately 0.2, and is invariant with drop diameter and also across the spray cases tested.

  14. Estimation of the diameter-charge distribution in polydisperse electrically charged sprays of electrically insulating liquids

    Energy Technology Data Exchange (ETDEWEB)

    Rigit, A.R.H. [University of Sarawak, Faculty of Engineering, Kota Samarahan, Sarawak (Malaysia); Shrimpton, John S. [University of Southampton, Energy Technology Research Group, School of Engineering Sciences, Southampton (United Kingdom)

    2009-06-15

    The majority of scientific and industrial electrical spray applications make use of sprays that contain a range of drop diameters. Indirect evidence suggests the mean drop diameter and the mean drop charge level are usually correlated. In addition, within each drop diameter class there is every reason to suspect a distribution of charge levels exist for a particular drop diameter class. This paper presents an experimental method that uses the joint PDF of drop velocity and diameter, obtained from phase Doppler anemometry measurements, and directly obtained spatially resolved distributions of the mass and charge flux to obtain a drop diameter and charge frequency distribution. The method is demonstrated using several data-sets obtained from experimental measurements of steady poly-disperse sprays of an electrically insulating liquid produced with the charge injection technique. The space charge repulsion in the spray plume produces a hollow cone spray structure. In addition an approximate self-similarity is observed, with the maximum radial mass and charge flow occurring at r/d{proportional_to}200. The charge flux profile is slightly offset from the mass flux profile, and this gives direct evidence that the spray specific charge increases from approximately 20% of the bulk mean spray specific charge on the spray axis to approximately 200% of the bulk mean specific charge in the periphery of the spray. The results from the drop charge estimation model suggest a complex picture of the correlation between drop charge and drop diameter, with spray specific charge, injection velocity and orifice diameter all contributing to the shape of the drop diameter-charge distribution. Mean drop charge as a function of the Rayleigh limit is approximately 0.2, and is invariant with drop diameter and also across the spray cases tested. (orig.)

  15. Corrosion and deposit evaluation in large diameter pipes using radiography

    International Nuclear Information System (INIS)

    Boateng, A.

    2012-01-01

    of misinterpreting the failure of such pipe component. On the whole the TRT method overestimated the degree of penetrated corrosion attack in the tangential position in the neighbourhood of 9% and the Double Wall Technique (DWT) had a maximum underestimation of 1.3% of the corroded surface area of the pipe. The TRT measurement of depth of local corrosion (pitting) was within an accuracy of ±0.37 mm and the measurement of corroded surface area (pit diameter) using DWT was within an accuracy of ± 0.29 mm. These tolerance limits are 5% less than the wall thickness of the pipe. The statistical interpretation of the obtained results from the study can reliably be used to develop a baseline data for the investigated pipe, through which effective monitoring of corrosion and deposit can be executed. (au)

  16. Experimental investigation on motive nozzle throat diameter for an ejector expansion refrigeration system

    International Nuclear Information System (INIS)

    Bilir Sag, Nagihan; Ersoy, H. Kursad

    2016-01-01

    Highlights: • Effects of nozzle throat diameter and its location on performance were investigated. • The nozzle has an optimum throat diameter under the experiment condition. • The maximum performance has been achieved by using optimum nozzle throat diameter. • The variation of nozzle throat diameter with condenser water inlet temperature was examined. • Motive nozzle has no optimum position in the ejector refrigeration system. - Abstract: In this study, ejector was used to reduce throttling losses in a vapour compression refrigeration system. Effects on system performance of throat diameter and position of motive nozzle of ejector were investigated experimentally. An ejector was designed based on the established mathematical model and manufactured. The experiments were carried out by using different primary nozzle throat diameters. The experiments were further conducted by changing condenser water inlet temperature, which is one of the external parameters. The experimental results of the ejector system and those of the classic system were compared under same external operating conditions and for the same cooling capacity. In order to obtain same external operating conditions in both systems, the inlet conditions of the brine supplied to the evaporator and inlet water conditions (flow rate and temperature) to the condenser were kept constant. Maximum performance was obtained when the primary nozzle throat diameter was 2.3 mm within the areas considered in this study. When compared, it was experimentally determined that the ejector system that uses the optimum motive nozzle throat diameter exhibits higher COP than the classic system by 5–13%. Furthermore, it was found that the variation of coefficient of performance based on position of motive nozzle in two-phase ejector expander refrigeration cycle is lower than 1%.

  17. Sagittal Abdominal Diameter: Application in Clinical Practice

    Directory of Open Access Journals (Sweden)

    Thaís Da Silva-Ferreira

    2014-05-01

    Full Text Available Excess visceral fat is associated with cardiovascular risk factors. Sagittal abdominal diameter (SAD has recently been highlighted as an indicator of abdominal obesity, and also may be useful in predicting cardiovascular risk. The purpose of the present study was to review the scientific literature on the use of SAD in adult nutritional assessment. A search was conducted for scientific articles in the following electronic databases: SciELO , MEDLINE (PubMed and Virtual Health Library. SAD is more associated with abdominal fat (especially visceral, and with different cardiovascular risk factors, such as, insulin resistance, blood pressure, and serum lipoproteins than the traditional methods of estimating adiposity, such as body mass index and waist-to-hip ratio. SAD can also be used in association with other anthropometric measures. There are still no cut-off limits established to classify SAD as yet. SAD can be an alternative measure to estimate visceral adiposity. However, the few studies on this diameter, and the lack of consensus on the anatomical site to measure SAD, are obstacles to establish cut-off limits to classify it.

  18. Cooperative spreading processes in multiplex networks.

    Science.gov (United States)

    Wei, Xiang; Chen, Shihua; Wu, Xiaoqun; Ning, Di; Lu, Jun-An

    2016-06-01

    This study is concerned with the dynamic behaviors of epidemic spreading in multiplex networks. A model composed of two interacting complex networks is proposed to describe cooperative spreading processes, wherein the virus spreading in one layer can penetrate into the other to promote the spreading process. The global epidemic threshold of the model is smaller than the epidemic thresholds of the corresponding isolated networks. Thus, global epidemic onset arises in the interacting networks even though an epidemic onset does not arise in each isolated network. Simulations verify the analysis results and indicate that cooperative spreading processes in multiplex networks enhance the final infection fraction.

  19. Bank Lending, Housing and Spreads

    DEFF Research Database (Denmark)

    Aslam, Aqib; Santoro, Emiliano

    The framework presented in this paper takes its cue from recent financial events and attempts to develop a tractable framework for policy analysis of macro-linkages, in particular a first attempt at the integration of an independent profit-maximising banking sector that lends to and borrows from...... agents in the economy, and through which changes in the monetary policy rate by the central bank are transmitted. The inter-linkages between housing and the role of the banking sector in the transmission of monetary policy is emphasized. Two competing effects are highlighted: (i) a financial accelerator...... channel, due to the presence of collateralized borrowers, and (ii) a banking attenuator effect, which crucially arises from the spread in interest rates caused by the introduction of monopolistically competitive financial intermediaries. We show how the classical amplification mechanism explored in models...

  20. Maximum stellar iron core mass

    Indian Academy of Sciences (India)

    60, No. 3. — journal of. March 2003 physics pp. 415–422. Maximum stellar iron core mass. F W GIACOBBE. Chicago Research Center/American Air Liquide ... iron core compression due to the weight of non-ferrous matter overlying the iron cores within large .... thermal equilibrium velocities will tend to be non-relativistic.

  1. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore. 11 refs., 4 figs

  2. Maximum entropy beam diagnostic tomography

    International Nuclear Information System (INIS)

    Mottershead, C.T.

    1985-01-01

    This paper reviews the formalism of maximum entropy beam diagnostic tomography as applied to the Fusion Materials Irradiation Test (FMIT) prototype accelerator. The same formalism has also been used with streak camera data to produce an ultrahigh speed movie of the beam profile of the Experimental Test Accelerator (ETA) at Livermore

  3. A portable storage maximum thermometer

    International Nuclear Information System (INIS)

    Fayart, Gerard.

    1976-01-01

    A clinical thermometer storing the voltage corresponding to the maximum temperature in an analog memory is described. End of the measurement is shown by a lamp switch out. The measurement time is shortened by means of a low thermal inertia platinum probe. This portable thermometer is fitted with cell test and calibration system [fr

  4. Neutron spectra unfolding with maximum entropy and maximum likelihood

    International Nuclear Information System (INIS)

    Itoh, Shikoh; Tsunoda, Toshiharu

    1989-01-01

    A new unfolding theory has been established on the basis of the maximum entropy principle and the maximum likelihood method. This theory correctly embodies the Poisson statistics of neutron detection, and always brings a positive solution over the whole energy range. Moreover, the theory unifies both problems of overdetermined and of underdetermined. For the latter, the ambiguity in assigning a prior probability, i.e. the initial guess in the Bayesian sense, has become extinct by virtue of the principle. An approximate expression of the covariance matrix for the resultant spectra is also presented. An efficient algorithm to solve the nonlinear system, which appears in the present study, has been established. Results of computer simulation showed the effectiveness of the present theory. (author)

  5. Mammographic image restoration using maximum entropy deconvolution

    International Nuclear Information System (INIS)

    Jannetta, A; Jackson, J C; Kotre, C J; Birch, I P; Robson, K J; Padgett, R

    2004-01-01

    An image restoration approach based on a Bayesian maximum entropy method (MEM) has been applied to a radiological image deconvolution problem, that of reduction of geometric blurring in magnification mammography. The aim of the work is to demonstrate an improvement in image spatial resolution in realistic noisy radiological images with no associated penalty in terms of reduction in the signal-to-noise ratio perceived by the observer. Images of the TORMAM mammographic image quality phantom were recorded using the standard magnification settings of 1.8 magnification/fine focus and also at 1.8 magnification/broad focus and 3.0 magnification/fine focus; the latter two arrangements would normally give rise to unacceptable geometric blurring. Measured point-spread functions were used in conjunction with the MEM image processing to de-blur these images. The results are presented as comparative images of phantom test features and as observer scores for the raw and processed images. Visualization of high resolution features and the total image scores for the test phantom were improved by the application of the MEM processing. It is argued that this successful demonstration of image de-blurring in noisy radiological images offers the possibility of weakening the link between focal spot size and geometric blurring in radiology, thus opening up new approaches to system optimization

  6. 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

  7. A reexamination of the spreading center hypothesis for Ovda and Thetis Regiones, Venus

    International Nuclear Information System (INIS)

    Kiefer, W.S.

    1990-01-01

    Ceumpler, Head, and colleagues proposed that Ovda and Thetis Regiones are spreading centers. The strong positive correlation between geoid and topography observed in Ovda and Thetis is unlike that observed for terrestrial spreading centers. The maximum elevation expected for spreading centers on Venus is 1.5 km, and a cooling plate thermal model predicts a maximum geoid anomaly of 8 meters, both much less than observed. Even if a spreading center is operative in Ovda and Thetis, most of the geoid and topography must be due to other mechanisms. Crumpler et al. also proposed the existence of cross-strike discontinuities, interpreted as transform fault zones, but the evidence for these structures is not conclusive

  8. Spreading Dynamics of an Ellipsoidal Drop Impacting on a Heated Substrate

    Energy Technology Data Exchange (ETDEWEB)

    Yun, Sungchan [Korea Nat’l. Univ. of Transportation, Chungju (Korea, Republic of)

    2017-03-15

    Unlike spherical drop impact, ellipsoidal drop impact can control the bouncing height on a heated surface by significantly altering impact behavior. To scrutinize the effect of the aspect ratio (AR) of the drop on the bounce suppression, in this study, non-axisymmetric spreading behaviors are observed from two side views and characterized based on the spreading width of the drop for horizontal principal axes. In addition, the maximum spreading width is investigated for various ARs. The results show that as the AR increases, the maximum spreading width of the minor axis increases, whereas that of the major axis shows no significant variation. In the regime of high AR and high impact velocity, liquid fragmentations by three parts are observed during bouncing. These fragmentations are discussed in this work. The hydrodynamic features of ellipsoidal drop impact will help understand bouncing control on non-wetting surfaces for several applications, such as self-cleaning and spray cooling.

  9. Dimensions of the prostatic and membranous urethra in normal male dogs during maximum distension retrograde urethrocystography

    International Nuclear Information System (INIS)

    Feeney, D.A.; Johnston, G.R.; Osborne, C.A.; Tomlinson, M.J.

    1984-01-01

    Prostatic and membranous urethral diameter was measured in 24 normal mature male Beagle dogs during maximum distension retrograde urethrocystography. This technique involved retrograde urethral distension by infusion with contrast medium until the urinary bladder was distended and the vesicourethral junction remained opened as observed by fluoroscopy. Lateral and ventro-dorsal radiographs were made during subsequent injections of 5–10 ml of contrast medium. The prostatic urethra was consistently greater in diameter than the membranous urethra. However, the numerical ratio between the prostatic urethral diameter and the membranous urethral diameter varied among these dogs by a factor of 2 at the numerical extremes

  10. 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...

  11. On Maximum Entropy and Inference

    Directory of Open Access Journals (Sweden)

    Luigi Gresele

    2017-11-01

    Full Text Available Maximum entropy is a powerful concept that entails a sharp separation between relevant and irrelevant variables. It is typically invoked in inference, once an assumption is made on what the relevant variables are, in order to estimate a model from data, that affords predictions on all other (dependent variables. Conversely, maximum entropy can be invoked to retrieve the relevant variables (sufficient statistics directly from the data, once a model is identified by Bayesian model selection. We explore this approach in the case of spin models with interactions of arbitrary order, and we discuss how relevant interactions can be inferred. In this perspective, the dimensionality of the inference problem is not set by the number of parameters in the model, but by the frequency distribution of the data. We illustrate the method showing its ability to recover the correct model in a few prototype cases and discuss its application on a real dataset.

  12. Spreading of correlations in the Falicov-Kimball model

    Science.gov (United States)

    Herrmann, Andreas J.; Antipov, Andrey E.; Werner, Philipp

    2018-04-01

    We study dynamical properties of the one- and two-dimensional Falicov-Kimball model using lattice Monte Carlo simulations. In particular, we calculate the spreading of charge correlations in the equilibrium model and after an interaction quench. The results show a reduction of the light-cone velocity with interaction strength at low temperature, while the phase velocity increases. At higher temperature, the initial spreading is determined by the Fermi velocity of the noninteracting system and the maximum range of the correlations decreases with increasing interaction strength. Charge order correlations in the disorder potential enhance the range of the correlations. We also use the numerically exact lattice Monte Carlo results to benchmark the accuracy of equilibrium and nonequilibrium dynamical cluster approximation calculations. It is shown that the bias introduced by the mapping to a periodized cluster is substantial, and that from a numerical point of view, it is more efficient to simulate the lattice model directly.

  13. Maximum Water Hammer Sensitivity Analysis

    OpenAIRE

    Jalil Emadi; Abbas Solemani

    2011-01-01

    Pressure waves and Water Hammer occur in a pumping system when valves are closed or opened suddenly or in the case of sudden failure of pumps. Determination of maximum water hammer is considered one of the most important technical and economical items of which engineers and designers of pumping stations and conveyance pipelines should take care. Hammer Software is a recent application used to simulate water hammer. The present study focuses on determining significance of ...

  14. Maximum Gene-Support Tree

    Directory of Open Access Journals (Sweden)

    Yunfeng Shan

    2008-01-01

    Full Text Available Genomes and genes diversify during evolution; however, it is unclear to what extent genes still retain the relationship among species. Model species for molecular phylogenetic studies include yeasts and viruses whose genomes were sequenced as well as plants that have the fossil-supported true phylogenetic trees available. In this study, we generated single gene trees of seven yeast species as well as single gene trees of nine baculovirus species using all the orthologous genes among the species compared. Homologous genes among seven known plants were used for validation of the finding. Four algorithms—maximum parsimony (MP, minimum evolution (ME, maximum likelihood (ML, and neighbor-joining (NJ—were used. Trees were reconstructed before and after weighting the DNA and protein sequence lengths among genes. Rarely a gene can always generate the “true tree” by all the four algorithms. However, the most frequent gene tree, termed “maximum gene-support tree” (MGS tree, or WMGS tree for the weighted one, in yeasts, baculoviruses, or plants was consistently found to be the “true tree” among the species. The results provide insights into the overall degree of divergence of orthologous genes of the genomes analyzed and suggest the following: 1 The true tree relationship among the species studied is still maintained by the largest group of orthologous genes; 2 There are usually more orthologous genes with higher similarities between genetically closer species than between genetically more distant ones; and 3 The maximum gene-support tree reflects the phylogenetic relationship among species in comparison.

  15. LCLS Maximum Credible Beam Power

    International Nuclear Information System (INIS)

    Clendenin, J.

    2005-01-01

    The maximum credible beam power is defined as the highest credible average beam power that the accelerator can deliver to the point in question, given the laws of physics, the beam line design, and assuming all protection devices have failed. For a new accelerator project, the official maximum credible beam power is determined by project staff in consultation with the Radiation Physics Department, after examining the arguments and evidence presented by the appropriate accelerator physicist(s) and beam line engineers. The definitive parameter becomes part of the project's safety envelope. This technical note will first review the studies that were done for the Gun Test Facility (GTF) at SSRL, where a photoinjector similar to the one proposed for the LCLS is being tested. In Section 3 the maximum charge out of the gun for a single rf pulse is calculated. In Section 4, PARMELA simulations are used to track the beam from the gun to the end of the photoinjector. Finally in Section 5 the beam through the matching section and injected into Linac-1 is discussed

  16. The spreading of radiolabelled fatty suppository bases in the human rectum

    International Nuclear Information System (INIS)

    Sugito, Keiko; Ogata, Hiroyasu; Noguchi, Masahiro; Kogure, Takahashi; Takano, Masaaki; Maruyama, Yuzo; Sasaki, Yasuhito

    1988-01-01

    The purpose of this study was to develop a radiolabelling method for assessing the spreading of fatty suppository bases (Witepsol H-5, W-35 and S-55), and to apply this technique to the evaluation of suppository disposition in the human rectum. 99m/Tc was bound chemically to the bases Witepsol H-5 and W-35, and mixed physically with Witepsol S-55. The spreading of each suppository base was monitored by gamma-scintigraphy following rectal administration. The mean radioactivity remaining at the inserted region 4 h after administration was 44.2% of total activity. The mean perpendicular maximum spreading distance from this region was 7.7 cm on the scintigram near to the sigmoid colon. Defecation was suggested to be a factor influencing the spread of suppository bases. However, there was no clear relationship between the type of suppository base used and the extent of its spread within the rectum. 6 refs.; 4 figs.; 1 table

  17. Perineural spread in head and neck tumors.

    Science.gov (United States)

    Brea Álvarez, B; Tuñón Gómez, M

    2014-01-01

    Perineural spread is the dissemination of some types of head and neck tumors along nervous structures. Perineural spread has negative repercussions on treatment because it requires more extensive resection and larger fields of irradiation. Moreover, perineural spread is associated with increased local recurrence, and it is considered an independent indicator of poor prognosis in the TNM classification for tumor staging. However, perineural spread often goes undetected on imaging studies. In this update, we review the concept of perineural spread, its pathogenesis, and the main pathways and connections among the facial nerves, which are essential to understand this process. Furthermore, we discuss the appropriate techniques for imaging studies, and we describe and illustrate the typical imaging signs that help identify perineural spread on CT and MRI. Finally, we discuss the differential diagnosis with other entities. Copyright © 2013 SERAM. Published by Elsevier Espana. All rights reserved.

  18. Waste system optimization - can diameter selection

    International Nuclear Information System (INIS)

    Ashline, R.C.

    1983-08-01

    The purpose of the waste system optimization study is to define in terms of cost incentives the preferred waste package for HLW which has been converted to glass at a commercial reprocessing plant. The Waste Management Economic Model (WMEM) was employed to analyze the effect of varying important design parameters on the overall net present cost of waste handling. The parameters found to have the greatest effect on the calculated overall net present cost were can diameter, repository type (salt, basalt/bentonite, or welded tuff), allowable areal heat loading, and the repository availability date. The overall net present of a waste handling option is calculated over a 20-year operating period. It includes the total capital and operating costs associated with high-level and intermediate-level liquid waste storage, liquid waste solidification, hulls storage and compaction, and general process trash handling. It also includes the cask leasing and transportation costs associated with each waste type and the waste repository disposal costs. The waste repository disposal costs used in WMEM for this analysis were obtained from Battelle Pacific Northwest Laboratories and thir RECON model. 2 figures, 2 tables

  19. 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)

  20. MIMO Based Eigen-Space Spreading

    National Research Council Canada - National Science Library

    Eltawil, Ahmed

    2004-01-01

    .... Combination of this powerful technique with orthogonal frequency division multiplexing (OFDM) based modulation and traditional time and frequency spreading techniques results in a highly secure mode of communications...

  1. COMBINED SURGERY OF SPREAD THYROID CANCER

    Directory of Open Access Journals (Sweden)

    V. Zh. Brzhezovsky

    2014-01-01

    Full Text Available Results of treating of 99 patients with differentiated thyroid cancer spreading beyond the capsule of the organ were analysed. In most cases with spreading the tumor to the tracheal rings performing of organ-preserving operations (from “window-like” tracheal resections to circular tracheal resection with intertracheal anastomosis is possible. Choosing of type of operation to be performed depends on localisation and spread of tumor invasion of trachea, pharynx and esophagus. Using of combined operations in patients with locally-spread thyroid cancer allows to achieve long and stable remission in most of the cases.

  2. Energy Spread Sources in TESLA and TTF

    International Nuclear Information System (INIS)

    Mosnier, A.; Tessier, J.M.

    1995-03-01

    The beam energy spread in the TESLA linac must be small enough to limit the emittance dilution due to the dispersive effects. This report summarizes the major sources of energy spread both for the TESLA linac and the TTF linac, where these estimations will be carefully checked with beam experiments. The first part recalls the intra-bunch energy spread while the second part looks into the bunch-to-bunch energy spread induced by rf field fluctuations within the bunch train and from pulse-to-pulse. (author). 3 refs., 4 figs

  3. Generic maximum likely scale selection

    DEFF Research Database (Denmark)

    Pedersen, Kim Steenstrup; Loog, Marco; Markussen, Bo

    2007-01-01

    in this work is on applying this selection principle under a Brownian image model. This image model provides a simple scale invariant prior for natural images and we provide illustrative examples of the behavior of our scale estimation on such images. In these illustrative examples, estimation is based......The fundamental problem of local scale selection is addressed by means of a novel principle, which is based on maximum likelihood estimation. The principle is generally applicable to a broad variety of image models and descriptors, and provides a generic scale estimation methodology. The focus...

  4. Olive oil in food spreads

    Directory of Open Access Journals (Sweden)

    Blanco Muñoz, Miguel A.

    2004-03-01

    Full Text Available Chemical hydrogenation of unsaturated fatty acids is a commonly applied reaction to food industries. The process may imply the movement of double bonds in their positions on the fatty acid carbon chain, producing positional and geometrical isomers ( trans fatty acids. Through hydrogenation, unsaturated oils are converted to margarines and vegetable shortenings. The presence of trans fatty acids in foods is undesirable, as trans fatty acids raise the plasma levels of total and low-density lipoproteins (LDL, while decrease the plasma level of high-density lipoproteins (HDL, among other effects. The use of olive oil to prepare fat spread opens new insights into the commercial development of healthy novel foods with a positive image in terms of consumer appeal.La hidrogenación química de los ácidos grasos insaturados es una reacción que se utiliza con frecuencia en la industria alimentaria. El proceso implica el movimiento de los dobles enlaces en la cadena hidrocarbonada de los ácidos grasos, y la aparición de isómeros posicionales y geométricos (ácidos grasos trans . La ingesta inadecuada de alimentos que pueden contener cantidades significativas de ácidos grasos trans se asocia con el aumento en sangre de colesterol total y LDL, y la disminución de HDL, entre otros efectos. Por lo tanto, el uso de aceite de oliva en la preparación de grasas para untar constituye un importante avance en el desarrollo comercial de nuevos alimentos saludables con una imagen positiva para el consumidor.

  5. Anomalous diffusion spreads its wings

    Energy Technology Data Exchange (ETDEWEB)

    Klafter, J. [School of Chemistry, Tel Aviv University, Tel-Aviv (Israel)]. E-mail: klafter@post.tau.ac.il; Sokolov, I.M. [Institute of Physics, Humboldt University, Berlin (Germany)]. E-mail: igor.sokolov@physik.hu-berlin.de

    2005-08-01

    An increasing number of natural phenomena do not fit into the relatively simple description of diffusion developed by Einstein a century ago. As all of us are no doubt aware, this year has been declared 'world year of physics' to celebrate the three remarkable breakthroughs made by Albert Einstein in 1905. However, it is not so well known that Einstein's work on Brownian motion - the random motion of tiny particles first observed and investigated by the botanist Robert Brown in 1827 - has been cited more times in the scientific literature than his more famous papers on special relativity and the quantum nature of light. In a series of publications that included his doctoral thesis, Einstein derived an equation for Brownian motion from microscopic principles - a feat that ultimately enabled Jean Perrin and others to prove the existence of atoms (see 'Einstein's random walk' Physics World January pp19-22). Einstein was not the only person thinking about this type of problem. The 27 July 1905 issue of Nature contained a letter with the title 'The problem of the random walk' by the British statistician Karl Pearson, who was interested in the way that mosquitoes spread malaria, which he showed was described by the well-known diffusion equation. As such, the displacement of a mosquito from its initial position is proportional to the square root of time, and the distribution of the positions of many such 'random walkers' starting from the same origin is Gaussian in form. The random walk has since turned out to be intimately linked to Einstein's work on Brownian motion, and has become a major tool for understanding diffusive processes in nature. (U.K.)

  6. Epidemic Spread in Networks Induced by Deactivation Mechanism

    International Nuclear Information System (INIS)

    Yu Xiaoling; Wu Xiao; Zhang Duanming; Li Zhihao; Liang Fang; Wang Xiaoyu

    2008-01-01

    We have studied the topology and epidemic spreading behaviors on the networks in which deactivation mechanism and long-rang connection are coexisted. By means of numerical simulation, we find that the clustering coefficient C and the Pearson correlation coefficient r decrease with increasing long-range connection μ and the topological state of the network changes into that of BA model at the end (when μ = 1). For the Susceptible-Infect-Susceptible model of epidemics, the epidemic threshold can reach maximum value at μ = 0.4 and presents two different variable states around μ = 0.4

  7. Extreme Maximum Land Surface Temperatures.

    Science.gov (United States)

    Garratt, J. R.

    1992-09-01

    There are numerous reports in the literature of observations of land surface temperatures. Some of these, almost all made in situ, reveal maximum values in the 50°-70°C range, with a few, made in desert regions, near 80°C. Consideration of a simplified form of the surface energy balance equation, utilizing likely upper values of absorbed shortwave flux (1000 W m2) and screen air temperature (55°C), that surface temperatures in the vicinity of 90°-100°C may occur for dry, darkish soils of low thermal conductivity (0.1-0.2 W m1 K1). Numerical simulations confirm this and suggest that temperature gradients in the first few centimeters of soil may reach 0.5°-1°C mm1 under these extreme conditions. The study bears upon the intrinsic interest of identifying extreme maximum temperatures and yields interesting information regarding the comfort zone of animals (including man).

  8. Modelling the minislump spread of superplasticized PPC paste using RLS with the application of Random Kitchen sink

    Science.gov (United States)

    Sathyan, Dhanya; Anand, K. B.; Jose, Chinnu; Aravind, N. R.

    2018-02-01

    Super plasticizers(SPs) are added to the concrete to improve its workability with out changing the water cement ratio. Property of fresh concrete is mainly governed by the cement paste which depends on the dispersion of cement particle. Cement dispersive properties of the SP depends up on its dosage and the family. Mini slump spread diameter with different dosages and families of SP is taken as the measure of workability characteristic of cement paste chosen for measuring the rheological properties of cement paste. The main purpose of this study includes measure the dispersive ability of different families of SP by conducting minislump test and model the minislump spread diameter of the super plasticized Portland Pozzolona Cement (PPC)paste using regularized least square (RLS) approach along with the application of Random kitchen sink (RKS) algorithm. For preparing test and training data for the model 287 different mixes were prepared in the laboratory at a water cement ratio of 0.37 using four locally available brand of Portland Pozzolona cement (PPC) and SP belonging to four different families. Water content, cement weight and amount of SP (by considering it as seven separate input based on their family and brand) were the input parameters and mini slump spread diameter was the output parameter for the model. The variation of predicted and measured values of spread diameters were compared and validated. From this study it was observed that, the model could effectively predict the minislump spread of cement paste

  9. Demineralized water flow cancelling experiments with ice plug into high diameter horizontal tube (300 nominal diameter)

    International Nuclear Information System (INIS)

    Gyongyosi, T.; Valeca, S.; Corbescu, B.; Puiu, D.; Panaitescu, V. N.

    2015-01-01

    The isolation with ice plug of a high diameter horizontal pipeline section is a specific technique for repairs activities/ replacements of components owning to thermo-hydraulic installations working with liquid agents. The application of such technique don.t assumes stopping of the entire system. The ice plugging inside of the pipeline assumes using of a special device and of an own specific technology for application. The paper contains a brief description of the experimental technological facilities used, followed by setting off the main moments in evolution of two experimental tests carried out on the test section with 300 mm nominal diameter for demineralized water and, finally, by a brief results analysis and some conclusions. The paper is dedicated to the specialists working in the research and technological engineering. (authors)

  10. Modelling diameter growth, mortality and recruitment of trees in ...

    African Journals Online (AJOL)

    Modelling diameter growth, mortality and recruitment of trees in miombo woodlands of Tanzania. ... Individual tree diameter growth and mortality models, and area-based recruitment models were developed. ... AJOL African Journals Online.

  11. 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

  12. Shiitake mushroom production on small diameter oak logs in Ohio

    Science.gov (United States)

    S.M. Bratkovich

    1991-01-01

    Yields of different strains of shiitake mushrooms (Lentinus edodes) were evaluated when produced on small diameter oak logs in Ohio. Logs averaging between 3-4 inches in diameter were inoculated with four spawn strains in 1985.

  13. 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

  14. Rotated Walsh-Hadamard Spreading with Robust Channel Estimation for a Coded MC-CDMA System

    Directory of Open Access Journals (Sweden)

    Raulefs Ronald

    2004-01-01

    Full Text Available We investigate rotated Walsh-Hadamard spreading matrices for a broadband MC-CDMA system with robust channel estimation in the synchronous downlink. The similarities between rotated spreading and signal space diversity are outlined. In a multiuser MC-CDMA system, possible performance improvements are based on the chosen detector, the channel code, and its Hamming distance. By applying rotated spreading in comparison to a standard Walsh-Hadamard spreading code, a higher throughput can be achieved. As combining the channel code and the spreading code forms a concatenated code, the overall minimum Hamming distance of the concatenated code increases. This asymptotically results in an improvement of the bit error rate for high signal-to-noise ratio. Higher convolutional channel code rates are mostly generated by puncturing good low-rate channel codes. The overall Hamming distance decreases significantly for the punctured channel codes. Higher channel code rates are favorable for MC-CDMA, as MC-CDMA utilizes diversity more efficiently compared to pure OFDMA. The application of rotated spreading in an MC-CDMA system allows exploiting diversity even further. We demonstrate that the rotated spreading gain is still present for a robust pilot-aided channel estimator. In a well-designed system, rotated spreading extends the performance by using a maximum likelihood detector with robust channel estimation at the receiver by about 1 dB.

  15. On entanglement spreading from holography

    Energy Technology Data Exchange (ETDEWEB)

    Mezei, Márk [Princeton Center for Theoretical Science, Princeton University,Princeton, NJ 08544 (United States)

    2017-05-11

    A global quench is an interesting setting where we can study thermalization of subsystems in a pure state. We investigate entanglement entropy (EE) growth in global quenches in holographic field theories and relate some of its aspects to quantities characterizing chaos. More specifically we obtain four key results: We prove holographic bounds on the entanglement velocity v{sub E} and the butterfly effect speed v{sub B} that arises in the study of chaos. We obtain the EE as a function of time for large spherical entangling surfaces analytically. We show that the EE is insensitive to the details of the initial state or quench protocol. In a thermofield double state we determine analytically the two-sided mutual information between two large concentric spheres separated in time. We derive a bound on the rate of growth of EE for arbitrary shapes, and develop an expansion for EE at early times. In a companion paper https://arxiv.org/abs/1608.05101, these results are put in the broader context of EE growth in chaotic systems: we relate EE growth to the chaotic spreading of operators, derive bounds on EE at a given time, and compare the holographic results to spin chain numerics and toy models. In this paper, we perform holographic calculations that provide the basis of arguments presented in that paper. We prove holographic bounds on the entanglement velocity v{sub E} and the butterfly effect speed v{sub B} that arises in the study of chaos. We obtain the EE as a function of time for large spherical entangling surfaces analytically. We show that the EE is insensitive to the details of the initial state or quench protocol. In a thermofield double state we determine analytically the two-sided mutual information between two large concentric spheres separated in time. We derive a bound on the rate of growth of EE for arbitrary shapes, and develop an expansion for EE at early times.

  16. 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

  17. Spreading to localized targets in complex networks

    Science.gov (United States)

    Sun, Ye; Ma, Long; Zeng, An; Wang, Wen-Xu

    2016-12-01

    As an important type of dynamics on complex networks, spreading is widely used to model many real processes such as the epidemic contagion and information propagation. One of the most significant research questions in spreading is to rank the spreading ability of nodes in the network. To this end, substantial effort has been made and a variety of effective methods have been proposed. These methods usually define the spreading ability of a node as the number of finally infected nodes given that the spreading is initialized from the node. However, in many real cases such as advertising and news propagation, the spreading only aims to cover a specific group of nodes. Therefore, it is necessary to study the spreading ability of nodes towards localized targets in complex networks. In this paper, we propose a reversed local path algorithm for this problem. Simulation results show that our method outperforms the existing methods in identifying the influential nodes with respect to these localized targets. Moreover, the influential spreaders identified by our method can effectively avoid infecting the non-target nodes in the spreading process.

  18. Epidemic spreading through direct and indirect interactions.

    Science.gov (United States)

    Ganguly, Niloy; Krueger, Tyll; Mukherjee, Animesh; Saha, Sudipta

    2014-09-01

    In this paper we study the susceptible-infected-susceptible epidemic dynamics, considering a specialized setting where popular places (termed passive entities) are visited by agents (termed active entities). We consider two types of spreading dynamics: direct spreading, where the active entities infect each other while visiting the passive entities, and indirect spreading, where the passive entities act as carriers and the infection is spread via them. We investigate in particular the effect of selection strategy, i.e., the way passive entities are chosen, in the spread of epidemics. We introduce a mathematical framework to study the effect of an arbitrary selection strategy and derive formulas for prevalence, extinction probabilities, and epidemic thresholds for both indirect and direct spreading. We also obtain a very simple relationship between the extinction probability and the prevalence. We pay special attention to preferential selection and derive exact formulas. The analysis reveals that an increase in the diversity in the selection process lowers the epidemic thresholds. Comparing the direct and indirect spreading, we identify regions in the parameter space where the prevalence of the indirect spreading is higher than the direct one.

  19. Fluorescent visualization of a spreading surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Fallest, David W; Lichtenberger, Adele M; Fox, Christopher J; Daniels, Karen E, E-mail: kdaniel@ncsu.ed [Department of Physics, North Carolina State University, Raleigh, NC 27695 (United States)

    2010-07-15

    The spreading of surfactants on thin films is an industrially and medically important phenomenon, but the dynamics are highly nonlinear and visualization of the surfactant dynamics has been a long-standing experimental challenge. We perform the first quantitative, spatiotemporally resolved measurements of the spreading of an insoluble surfactant on a thin fluid layer. During the spreading process, we directly observe both the radial height profile of the spreading droplet and the spatial distribution of the fluorescently tagged surfactant. We find that the leading edge of a spreading circular layer of surfactant forms a Marangoni ridge in the underlying fluid, with a trough trailing the ridge as expected. However, several novel features are observed using the fluorescence technique, including a peak in the surfactant concentration that trails the leading edge, and a flat, monolayer-scale spreading film that differs from concentration profiles predicted by current models. Both the Marangoni ridge and the surfactant leading edge can be described to spread as R{approx}t{sup {delta}}. We find spreading exponents {delta}{sub H}{approx}0.30 and {delta}{sub {Gamma}}{approx}0.22 for the ridge peak and surfactant leading edge, respectively, which are in good agreement with theoretical predictions of {delta}=1/4. In addition, we observe that the surfactant leading edge initially leads the peak of the Marangoni ridge, with the peak later catching up to the leading edge.

  20. Age, spreading rates, and spreading asymmetry of the world's ocean crust

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The authors present four companion digital models of the age, age uncertainty, spreading rates and spreading asymmetries of the world's ocean basins as geographic...

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

    Directory of Open Access Journals (Sweden)

    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.

  2. System for memorizing maximum values

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1992-08-01

    The invention discloses a system capable of memorizing maximum sensed values. The system includes conditioning circuitry which receives the analog output signal from a sensor transducer. The conditioning circuitry rectifies and filters the analog signal and provides an input signal to a digital driver, which may be either linear or logarithmic. The driver converts the analog signal to discrete digital values, which in turn triggers an output signal on one of a plurality of driver output lines n. The particular output lines selected is dependent on the converted digital value. A microfuse memory device connects across the driver output lines, with n segments. Each segment is associated with one driver output line, and includes a microfuse that is blown when a signal appears on the associated driver output line.

  3. Remarks on the maximum luminosity

    Science.gov (United States)

    Cardoso, Vitor; Ikeda, Taishi; Moore, Christopher J.; Yoo, Chul-Moon

    2018-04-01

    The quest for fundamental limitations on physical processes is old and venerable. Here, we investigate the maximum possible power, or luminosity, that any event can produce. We show, via full nonlinear simulations of Einstein's equations, that there exist initial conditions which give rise to arbitrarily large luminosities. However, the requirement that there is no past horizon in the spacetime seems to limit the luminosity to below the Planck value, LP=c5/G . Numerical relativity simulations of critical collapse yield the largest luminosities observed to date, ≈ 0.2 LP . We also present an analytic solution to the Einstein equations which seems to give an unboundedly large luminosity; this will guide future numerical efforts to investigate super-Planckian luminosities.

  4. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-09-07

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  5. Scintillation counter, maximum gamma aspect

    International Nuclear Information System (INIS)

    Thumim, A.D.

    1975-01-01

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

  6. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yi; Zhao, Shiguang; Gao, Xin

    2014-01-01

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  7. Spread and Liquidity Issues: A markets comparison

    Directory of Open Access Journals (Sweden)

    Strašek Sebastjan

    2016-03-01

    Full Text Available The financial crises are closely connected with spread changes and liquidity issues. After defining and addressing spread considerations, we research in this paper the topic of liquidity issues in times of economic crisis. We analyse the liquidity effects as recorded on spreads of securities from different markets. We stipulate that higher international risk aversion in times of financial crises coincides with widening security spreads. The paper then introduces liquidity as a risk factor into the standard value-at-risk framework, using GARCH methodology. The comparison of results of these models suggests that the size of the tested markets does not have a strong effect on the models. Thus, we find that spread analysis is an appropriate tool for analysing liquidity issues during a financial crisis.

  8. Modeling Caribbean tree stem diameters from tree height and crown width measurements

    Science.gov (United States)

    Thomas Brandeis; KaDonna Randolph; Mike Strub

    2009-01-01

    Regression models to predict diameter at breast height (DBH) as a function of tree height and maximum crown radius were developed for Caribbean forests based on data collected by the U.S. Forest Service in the Commonwealth of Puerto Rico and Territory of the U.S. Virgin Islands. The model predicting DBH from tree height fit reasonably well (R2 = 0.7110), with...

  9. The spreading of focal brain edema induced by ultraviolet irradiation

    International Nuclear Information System (INIS)

    Ferszt, R.; Neu, S.; Cervos-Navarro, J.; Sperner, J.

    1978-01-01

    Focal brain edema limited to one cerebral hemisphere was produced by ultraviolet irradiation of the exposed cortex. Tissue water content was determined by the gravimetric method which allows microsampling. Therefore, the spread of edema around the small necrotic area be mapped more precisely than by determination of dry weight which calls for larger samples. As early as 30 min after irradiation, hyperemia and swelling of the brain are observed under the operating microscope. This correlates with venous stasis, hyperemia, and broadened perivascular spaces around venules and large capillaries accompanied by a marked rise in the specific weigth of the tissue. After 4h an edema front can be observed spreading from the perinerotic zone in which there is a marked rise in endothelial cell vesicular activity. Edema reaches maximum levels in the deep white matter at 48h post irradiation with normalisation of the tissue water content after 96h. The velocity at which the edema front spreads from the cortex to the periventricular area lies in the range of 0.25mm/h. Edema reabsorption coincides with signs of retrograde micropinocytosis in endothelial cells. (orig./AJ) [de

  10. Behavior of the Position-Spread Tensor in Diatomic Systems.

    Science.gov (United States)

    Brea, Oriana; El Khatib, Muammar; Angeli, Celestino; Bendazzoli, Gian Luigi; Evangelisti, Stefano; Leininger, Thierry

    2013-12-10

    The behavior of the Position-Spread Tensor (Λ) in a series of light diatomic molecules (either neutral or negative ions) is investigated at a Full Configuration Interaction level. This tensor, which is the second moment cumulant of the total position operator, is invariant with respect to molecular translations, while its trace is also rotationally invariant. Moreover, the tensor is additive in the case of noninteracting subsystems and can be seen as an intrinsic property of a molecule. In the present work, it is shown that the longitudinal component of the tensor, Λ∥, which is small for internuclear distances close to the equilibrium, tends to grow if the bond is stretched. A maximum is reached in the region of the bond breaking, then Λ∥ decreases and converges toward the isolated-atom value. The degenerate transversal components, Λ⊥, on the other hand, usually have a monotonic growth toward the atomic value. The Position Spread is extremely sensitive to reorganization of the molecular wave function, and it becomes larger in the case of an increase of the electron mobility, as illustrated by the neutral-ionic avoided crossing in LiF. For these reasons, the Position Spread can be an extremely useful property that characterizes the nature of the wave function in a molecular system.

  11. Spreading of focal brain edema induced by ultraviolet irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ferszt, R; Neu, S; Cervos-Navarro, J; Sperner, J [Freie Univ. Berlin (Germany, F.R.). Inst. fuer Neuropathologie

    1978-01-01

    Focal brain edema limited to one cerebral hemisphere was produced by ultraviolet irradiation of the exposed cortex. Tissue water content was determined by the gravimetric method which allows microsampling. Therefore, the spread of edema around the small necrotic area be mapped more precisely than by determination of dry weight which calls for larger samples. As early as 30 min after irradiation, hyperemia and swelling of the brain are observed under the operating microscope. This correlates with venous stasis, hyperemia, and broadened perivascular spaces around venules and large capillaries accompanied by a marked rise in the specific weigth of the tissue. After 4h an edema front can be observed spreading from the perinerotic zone in which there is a marked rise in endothelial cell vesicular activity. Edema reaches maximum levels in the deep white matter at 48h post irradiation with normalisation of the tissue water content after 96h. The velocity at which the edema front spreads from the cortex to the periventricular area lies in the range of 0.25mm/h. Edema reabsorption coincides with signs of retrograde micropinocytosis in endothelial cells.

  12. 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.

  13. Analysis of transit time spread on FBK silicon photomultipliers

    International Nuclear Information System (INIS)

    Acerbi, F.; Gola, A.; Ferri, A.; Zorzi, N.; Paternoster, G.; Piemonte, C.

    2015-01-01

    In this paper we studied one of the aspects potentially limiting the single-photon time-resolution (SPTR) of the silicon photomultiplier (SiPM): the transit time spread (TTS). We illuminated the SiPM in different positions with a fast-pulsed laser collimated to a circular spot of 0.2 mm-diameter and acquired bi-dimensional maps of the avalanche-signal arrival time of RGB and RGB-HD SiPMs, produced at FBK. We studied the effect of both the number of bonding wires connecting the device to the package and the layout of the top-metal connection (on the device). We found that the TTS does not simply depend on the trace length between the cell and the bonding pad and it could vary in the range between tens of picoseconds (with 3 bonding connections) to more than one hundred of picoseconds (with one connection)

  14. Development of Pistachio (Pistacia vera L.) spread.

    Science.gov (United States)

    Shakerardekani, Ahmad; Karim, Roselina; Ghazali, Hasanah Mohd; Chin, Nyuk Ling

    2013-03-01

    Pistachio nut (Pistacia vera L.) is one of the most delicious and nutritious nuts in the world. Pistachio spreads were developed using pistachio paste as the main component, icing sugar, soy protein isolate (SPI), and red palm oil (RPO), at different ratios. The highest mean scores of all the sensory attributes were depicted by spreads that were made without addition of SPI. It was found that the work of shear was 0 to 11.0 kg s for an acceptable spread. Sensory spreadability, overall texture, spreadability, and overall acceptability were negatively correlated (R > 0.83) with the work of shear of spreads. The findings indicated that the presence of RPO had a direct effect on the viscoelastic behavior of the pistachio spreads. The a values, which are related to the green color of the pistachio product ranged from 1.7 to 3.9 for spread without addition of RPO, and 4.0 to 5.3 in the presence of RPO. The development of pistachio spread would potentially increase the food uses of pistachio and introduce consumers with a healthier snack food. © 2013 Institute of Food Technologists®

  15. Maximum entropy and Bayesian methods

    International Nuclear Information System (INIS)

    Smith, C.R.; Erickson, G.J.; Neudorfer, P.O.

    1992-01-01

    Bayesian probability theory and Maximum Entropy methods are at the core of a new view of scientific inference. These 'new' ideas, along with the revolution in computational methods afforded by modern computers allow astronomers, electrical engineers, image processors of any type, NMR chemists and physicists, and anyone at all who has to deal with incomplete and noisy data, to take advantage of methods that, in the past, have been applied only in some areas of theoretical physics. The title workshops have been the focus of a group of researchers from many different fields, and this diversity is evident in this book. There are tutorial and theoretical papers, and applications in a very wide variety of fields. Almost any instance of dealing with incomplete and noisy data can be usefully treated by these methods, and many areas of theoretical research are being enhanced by the thoughtful application of Bayes' theorem. Contributions contained in this volume present a state-of-the-art overview that will be influential and useful for many years to come

  16. Biofilm formation on a TiO2 nanotube with controlled pore diameter and surface wettability

    International Nuclear Information System (INIS)

    Anitha, V C; Narayan Banerjee, Arghya; Woo Joo, Sang; Lee, Jin-Hyung; Lee, Jintae; Ki Min, Bong

    2015-01-01

    Titania (TiO 2 ) nanotube arrays (TNAs) with different pore diameters (140 − 20 nm) are fabricated via anodization using hydrofluoric acid (HF) containing ethylene glycol (EG) by changing the HF-to-EG volume ratio and the anodization voltage. To evaluate the effects of different pore diameters of TiO 2 nanotubes on bacterial biofilm formation, Shewanella oneidensis (S. oneidensis) MR-1 cells and a crystal-violet biofilm assay are used. The surface roughness and wettability of the TNA surfaces as a function of pore diameter, measured via the contact angle and AFM techniques, are correlated with the controlled biofilm formation. Biofilm formation increases with the decreasing nanotube pore diameter, and a 20 nm TiO 2 nanotube shows the maximum biofilm formation. The measurements revealed that 20 nm surfaces have the least hydrophilicity with the highest surface roughness of ∼17 nm and that they show almost a 90% increase in the effective surface area relative to the 140 nm TNAs, which stimulate the cells more effectively to produce the pili to attach to the surface for more biofilm formation. The results demonstrate that bacterial cell adhesion (and hence, biofilm formation) can effectively be controlled by tuning the roughness and wettability of TNAs via controlling the pore diameters of TNA surfaces. This biofilm formation as a function of the surface properties of TNAs can be a potential candidate for both medical applications and as electrodes in microbial fuel cells. (paper)

  17. An in-pipe mobile micromachine using fluid power. A mechanism adaptable to pipe diameters

    International Nuclear Information System (INIS)

    Yoshida, Kazuhiro; Yokota, Shinichi; Takahashi, Ken

    2000-01-01

    To realize micro maintenance robots for small diameter pipes of nuclear reactors and so on, high power in-pipe mobile micromachines have been required. The authors have proposed the bellows microactuator using fluid power and have tried to apply the actuators to in-pipe mobile micromachines. In the previous papers, some inchworm mobile machine prototypes with 25 mm in diameter are fabricated and the traveling performances are experimentally investigated. In this paper, to miniaturize the in-pipe mobile machine and to make it adaptable to pipe diameters, firstly, a simple rubber-tube actuator constrained with a coil-spring is proposed and the static characteristics are investigated. Secondly, a supporting mechanism which utilizes a toggle mechanism and is adaptable to pipe diameters is proposed and the supporting forces are investigated. Finally, an in-pipe mobile micromachine for pipe with 4 - 5 mm in diameter is fabricated and the maximum traveling velocity of 7 mm/s in both ahead and astern movements is experimentally verified. (author)

  18. Fire spread simulation of a full scale cable tunnel

    International Nuclear Information System (INIS)

    Huhtanen, R.

    1999-11-01

    A fire simulation of a full scale tunnel was performed by using the commercial code EFFLUENT as the simulation platform. Estimation was made for fire spread on the stacked cable trays, possibility of fire spread to the cable trays on the opposite wall of the tunnel, detection time of smoke detectors in the smouldering phase and response of sprinkler heads in the flaming phase. According to the simulation, the rise of temperature in the smouldering phase is minimal, only of the order 1 deg C. The estimates of optical density of smoke show that normal smoke detectors should give an alarm within 2-4 minutes from the beginning of the smouldering phase, depending on the distance to the detector (in this case it was assumed that the thermal source connected to the smoke source was 50 W). The flow conditions at smoke detectors may be challenging, because the velocity magnitude is rather low at this phase. At 4 minutes the maximum velocity at the detectors is 0.12 m/s. During the flaming phase (beginning from 11 minutes) fire spreads on the stacked cable trays in an expected way, although the ignition criterion seems to perform poorly when ignition of new objects is considered. The Upper cable trays are forced to ignite by boundary condition definitions according to the experience found from ti full scale experiment and an earlier simulation. After 30 minutes the hot layer in the room becomes so hot that it speeds up the fire spread and the rate of heat release of burning objects. Further, the hot layer ignites the cable trays on the opposite wall of the tunnel after 45 minutes. It is estimated that the sprinkler heads would be activated at 20-22 minutes near the fire source and at 24-28 minutes little further from the fire source when fast sprinkler heads are used. The slow heads are activated between 26-32 minutes. (orig.)

  19. Credit Spreads Across the Business Cycle

    DEFF Research Database (Denmark)

    Nielsen, Mads Stenbo

    This paper studies how corporate bond spreads vary with the business cycle. I show that both level and slope of empirical credit spread curves are correlated with the state of the economy, and I link this to variation in idiosyncratic jump risk. I develop a structural credit risk model...... that accounts for both business cycle and jump risk, and show by estimation that the model captures the counter-cyclical level and pro-cyclical slope of empirical credit spread curves. In addition, I provide a new procedure for estimation of idiosyncratic jump risk, which is consistent with observed shocks...

  20. Modelling unidirectional liquid spreading on slanted microposts

    DEFF Research Database (Denmark)

    Cavalli, Andrea; Blow, Matthew L.; Yeomans, Julia M.

    2013-01-01

    A lattice Boltzmann algorithm is used to simulate the slow spreading of drops on a surface patterned with slanted micro-posts. Gibb's pinning of the interface on the sides or top of the posts leads to unidirectional spreading over a wide range of contact angles and inclination angles of the posts....... Regimes for spreading in no, one or two directions are identified, and shown to agree well with a two-dimensional theory proposed in Chu, Xiao and Wang. A more detailed numerical analysis of the contact line shapes allows us to understand deviations from the two dimensional model, and to identify...

  1. Quantitative risk assessment of continuous liquid spill fires based on spread and burning behaviours

    DEFF Research Database (Denmark)

    Zhao, Jinlong; Huang, Hong; Li, Yuntao

    2017-01-01

    Spill fires usually occur during the storage and transportation of hazardous materials, posing a threat to the people and environment in their immediate proximity. In this paper, a classical Quantitative Risk Assessment (QRA) method is used to assess the risk of spill fires. In this method......, the maximum spread area and the steady burning area are introduced as parameters to clearly assess the range of influence of the spill fire. In the calculations, a modified spread model that takes into consideration the burning rate variation is established to calculate the maximum spread area. Furthermore......, large-scale experiments of spill fires on water and a glass sheet were conducted to verify the accuracy and application of the model. The results show that the procedure we developed can be used to quantitatively calculate the risk associated with a continuous spill fire....

  2. Maximum entropy principal for transportation

    International Nuclear Information System (INIS)

    Bilich, F.; Da Silva, R.

    2008-01-01

    In this work we deal with modeling of the transportation phenomenon for use in the transportation planning process and policy-impact studies. The model developed is based on the dependence concept, i.e., the notion that the probability of a trip starting at origin i is dependent on the probability of a trip ending at destination j given that the factors (such as travel time, cost, etc.) which affect travel between origin i and destination j assume some specific values. The derivation of the solution of the model employs the maximum entropy principle combining a priori multinomial distribution with a trip utility concept. This model is utilized to forecast trip distributions under a variety of policy changes and scenarios. The dependence coefficients are obtained from a regression equation where the functional form is derived based on conditional probability and perception of factors from experimental psychology. The dependence coefficients encode all the information that was previously encoded in the form of constraints. In addition, the dependence coefficients encode information that cannot be expressed in the form of constraints for practical reasons, namely, computational tractability. The equivalence between the standard formulation (i.e., objective function with constraints) and the dependence formulation (i.e., without constraints) is demonstrated. The parameters of the dependence-based trip-distribution model are estimated, and the model is also validated using commercial air travel data in the U.S. In addition, policy impact analyses (such as allowance of supersonic flights inside the U.S. and user surcharge at noise-impacted airports) on air travel are performed.

  3. Spread of dwarf mistletoe from discrete seed sources into young stands of ponderosa and Jeffrey pines

    Science.gov (United States)

    J. R. Parmeter Jr.

    1972-01-01

    The maximum distance of spread of dwarf mistletoes from isolated overstory pines into surrounding reproduction averages 120 feet. The rate of infection in young trees declined as distance from the seed source increased and was generally greatest in the direction of prevailing winds. This pattern of infection was similar to the previously reported pattern of seed...

  4. Functional properties of a new spread based on olive oil and honeybees

    Directory of Open Access Journals (Sweden)

    Asma Tekiki

    2018-01-01

    Full Text Available a new alimentary concept has been developed since the 80’s. This one is called “functional food”.  In this context, the olive oil and honey are traditionally used in their initial state as a basic food. They are considered as a potential source of new bioactive products from which we can formulate several functional foods. This work will focus on the elaboration of a new spread of honey and olive oil using beeswax as an emulsifier. Physical-chemical characterization, antioxidant and antibacterial activity were evaluated. As for the phenols content, spreads prepared from thyme honey has the highest content (337 mg GAE/kg compared to other spreads. The antioxidant activity was evaluated by three different methods namely: DPPH test, ABTS + test and the iron reduction method (FRAP which proves that this last has a higher activity than the other spreads (EC50 of 70 mg /L using DPPH, EC50 of 20 mg /L using ABTS. An agar-well diffusion assay was used to assess the activity of honeys against seven bacteria strains. All prepared spreads honey samples showed highest antibacterial activity against all bacterial strains tested (diameter of ZI > 20mm. Hence, we note that our new spread proved by excellence to be a functional food due to the high content of phenols and the important antibacterial and antioxidant activities.

  5. Biomechanical optimization of implant diameter and length for immediate loading: a nonlinear finite element analysis.

    Science.gov (United States)

    Kong, Liang; Gu, Zexu; Li, Tao; Wu, Junjie; Hu, Kaijin; Liu, Yanpu; Zhou, Hongzhi; Liu, Baolin

    2009-01-01

    A nonlinear finite element method was applied to examine the effects of implant diameter and length on the maximum von Mises stresses in the jaw, and to evaluate the maximum displacement of the implant-abutment complex in immediate-loading models. The implant diameter (D) ranged from 3.0 to 5.0 mm and implant length (L) ranged from 6.0 to 16.0 mm. The results showed that the maximum von Mises stress in cortical bone was decreased by 65.8% under a buccolingual load with an increase in D. In cancellous bone, it was decreased by 71.5% under an axial load with an increase in L. The maximum displacement in the implant-abutment complex decreased by 64.8% under a buccolingual load with an increase in D. The implant was found to be more sensitive to L than to D under axial loads, while D played a more important role in enhancing its stability under buccolingual loads. When D exceeded 4.0 mm and L exceeded 11.0 mm, both minimum stress and displacement were obtained. Therefore, these dimensions were the optimal biomechanical selections for immediate-loading implants in type B/2 bone.

  6. Epidemic spreading in a hierarchical social network.

    Science.gov (United States)

    Grabowski, A; Kosiński, R A

    2004-09-01

    A model of epidemic spreading in a population with a hierarchical structure of interpersonal interactions is described and investigated numerically. The structure of interpersonal connections is based on a scale-free network. Spatial localization of individuals belonging to different social groups, and the mobility of a contemporary community, as well as the effectiveness of different interpersonal interactions, are taken into account. Typical relations characterizing the spreading process, like a range of epidemic and epidemic curves, are discussed. The influence of preventive vaccinations on the spreading process is investigated. The critical value of preventively vaccinated individuals that is sufficient for the suppression of an epidemic is calculated. Our results are compared with solutions of the master equation for the spreading process and good agreement of the character of this process is found.

  7. Heterogeneous incidence and propagation of spreading depolarizations

    Science.gov (United States)

    Kaufmann, Dan; Theriot, Jeremy J; Zyuzin, Jekaterina; Service, C Austin; Chang, Joshua C; Tang, Y Tanye; Bogdanov, Vladimir B; Multon, Sylvie; Schoenen, Jean; Ju, Y Sungtaek

    2016-01-01

    Spreading depolarizations are implicated in a diverse set of neurologic diseases. They are unusual forms of nervous system activity in that they propagate very slowly and approximately concentrically, apparently not respecting the anatomic, synaptic, functional, or vascular architecture of the brain. However, there is evidence that spreading depolarizations are not truly concentric, isotropic, or homogeneous, either in space or in time. Here we present evidence from KCl-induced spreading depolarizations, in mouse and rat, in vivo and in vitro, showing the great variability that these depolarizations can exhibit. This variability can help inform the mechanistic understanding of spreading depolarizations, and it has implications for their phenomenology in neurologic disease. PMID:27562866

  8. Interference management using direct sequence spread spectrum ...

    African Journals Online (AJOL)

    Interference management using direct sequence spread spectrum (DSSS) technique ... Journal of Fundamental and Applied Sciences ... Keywords: DSSS, LTE network; Wi-Fi network; SINR; interference management and interference power.

  9. Flame spread along thermally thick horizontal rods

    Science.gov (United States)

    Higuera, F. J.

    2002-06-01

    An analysis is carried out of the spread of a flame along a horizontal solid fuel rod, for which a weak aiding natural convection flow is established in the underside of the rod by the action of the axial gradient of the pressure variation that gravity generates in the warm gas surrounding the flame. The spread rate is determined in the limit of infinitely fast kinetics, taking into account the effect of radiative losses from the solid surface. The effect of a small inclination of the rod is discussed, pointing out a continuous transition between upward and downward flame spread. Flame spread along flat-bottomed solid cylinders, for which the gradient of the hydrostatically generated pressure drives the flow both along and across the direction of flame propagation, is also analysed.

  10. Spreading paths in partially observed social networks

    OpenAIRE

    Onnela, Jukka-Pekka; Christakis, Nicholas A.

    2012-01-01

    Understanding how and how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading paths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using a static, s...

  11. Mapping the Spread of Mounted Warfare

    Directory of Open Access Journals (Sweden)

    Peter Turchin

    2016-12-01

    Full Text Available Military technology is one of the most important factors affecting the evolution of complex societies. In particular, mounted warfare, the use of horse-riders in military operations, revolutionized war as it spread to different parts of Eurasia and Africa during the Ancient and Medieval eras, and to the Americas during the Early Modern period. Here we use a variety of sources to map this spread.

  12. Ignition and spread of electrical wire fires

    OpenAIRE

    Huang, Xinyan

    2012-01-01

    Ignition of electrical wires by external heating is investigated in order to gain a better understanding of the initiation of electrical-wire fires. An ignition-to- spread model is developed to systematically explain ignition and the following transition to spread. The model predicts that for a higher-conductance wire it is more difficult to achieve ignition and the weak flame may extinguish during the transition phase because of a large conductive heat loss along the wire core. Wires with tw...

  13. Spreading characteristics of proprietary rectal steroid preparations

    International Nuclear Information System (INIS)

    Hay, D.J.

    1982-01-01

    Three types of rectal steroid preparation were labelled with Technetium 99 or Indium 111, and the extent of spread of each within the bowel was followed, immediately after administration and at 2hrs, using a gamma camera. Patients with ulcerative colitis were compared with controls. Results indicate that 'Colifoam' enema and 'Predsol' suppository act mainly in the rectum, but 'Predsol retention' enema spreads further into the colon, making it more useful for patients with extensive ulcerative colitis. (U.K.)

  14. 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

  15. Spectral shaping of a randomized PWM DC-DC converter using maximum entropy probability distributions

    CSIR Research Space (South Africa)

    Dove, Albert

    2017-01-01

    Full Text Available maintaining constraints in a DC-DC converter is investigated. A probability distribution whose aim is to ensure maximal harmonic spreading and yet mainaint constraints is presented. The PDFs are determined from a direct application of the method of Maximum...

  16. Last Glacial Maximum Salinity Reconstruction

    Science.gov (United States)

    Homola, K.; Spivack, A. J.

    2016-12-01

    It has been previously demonstrated that salinity can be reconstructed from sediment porewater. The goal of our study is to reconstruct high precision salinity during the Last Glacial Maximum (LGM). Salinity is usually determined at high precision via conductivity, which requires a larger volume of water than can be extracted from a sediment core, or via chloride titration, which yields lower than ideal precision. It has been demonstrated for water column samples that high precision density measurements can be used to determine salinity at the precision of a conductivity measurement using the equation of state of seawater. However, water column seawater has a relatively constant composition, in contrast to porewater, where variations from standard seawater composition occur. These deviations, which affect the equation of state, must be corrected for through precise measurements of each ion's concentration and knowledge of apparent partial molar density in seawater. We have developed a density-based method for determining porewater salinity that requires only 5 mL of sample, achieving density precisions of 10-6 g/mL. We have applied this method to porewater samples extracted from long cores collected along a N-S transect across the western North Atlantic (R/V Knorr cruise KN223). Density was determined to a precision of 2.3x10-6 g/mL, which translates to salinity uncertainty of 0.002 gms/kg if the effect of differences in composition is well constrained. Concentrations of anions (Cl-, and SO4-2) and cations (Na+, Mg+, Ca+2, and K+) were measured. To correct salinities at the precision required to unravel LGM Meridional Overturning Circulation, our ion precisions must be better than 0.1% for SO4-/Cl- and Mg+/Na+, and 0.4% for Ca+/Na+, and K+/Na+. Alkalinity, pH and Dissolved Inorganic Carbon of the porewater were determined to precisions better than 4% when ratioed to Cl-, and used to calculate HCO3-, and CO3-2. Apparent partial molar densities in seawater were

  17. Maximum Parsimony on Phylogenetic networks

    Science.gov (United States)

    2012-01-01

    Background Phylogenetic networks are generalizations of phylogenetic trees, that are used to model evolutionary events in various contexts. Several different methods and criteria have been introduced for reconstructing phylogenetic trees. Maximum Parsimony is a character-based approach that infers a phylogenetic tree by minimizing the total number of evolutionary steps required to explain a given set of data assigned on the leaves. Exact solutions for optimizing parsimony scores on phylogenetic trees have been introduced in the past. Results In this paper, we define the parsimony score on networks as the sum of the substitution costs along all the edges of the network; and show that certain well-known algorithms that calculate the optimum parsimony score on trees, such as Sankoff and Fitch algorithms extend naturally for networks, barring conflicting assignments at the reticulate vertices. We provide heuristics for finding the optimum parsimony scores on networks. Our algorithms can be applied for any cost matrix that may contain unequal substitution costs of transforming between different characters along different edges of the network. We analyzed this for experimental data on 10 leaves or fewer with at most 2 reticulations and found that for almost all networks, the bounds returned by the heuristics matched with the exhaustively determined optimum parsimony scores. Conclusion The parsimony score we define here does not directly reflect the cost of the best tree in the network that displays the evolution of the character. However, when searching for the most parsimonious network that describes a collection of characters, it becomes necessary to add additional cost considerations to prefer simpler structures, such as trees over networks. The parsimony score on a network that we describe here takes into account the substitution costs along the additional edges incident on each reticulate vertex, in addition to the substitution costs along the other edges which are

  18. Dynamical Model about Rumor Spreading with Medium

    Directory of Open Access Journals (Sweden)

    Xiaxia Zhao

    2013-01-01

    Full Text Available Rumor is a kind of social remark, that is untrue, and not be confirmed, and spreads on a large scale in a short time. Usually, it can induce a cloud of pressure, anxiety, and panic. Traditionally, it is propagated by word of mouth. Nowadays, with the emergence of the internet, rumors can be spread by instant messengers, emails, or publishing. With this new pattern of spreading, an ISRW dynamical model considering the medium as a subclass is established. Beside the dynamical analysis of the model, we mainly explore the mechanism of spreading of individuals-to-individuals and medium-to-individual. By numerical simulation, we find that if we want to control the rumor spreading, it will not only need to control the rate of change of the spreader subclass, but also need to control the change of the information about rumor in medium which has larger influence. Moreover, to control the effusion of rumor is more important than deleting existing information about rumor. On the one hand, government should enhance the management of internet. On the other hand, relevant legal institutions for punishing the rumor creator and spreader on internet who can be tracked should be established. Using this way, involved authorities can propose efficient measures to control the rumor spreading to keep the stabilization of society and development of economy.

  19. Gossip spread in social network Models

    Science.gov (United States)

    Johansson, Tobias

    2017-04-01

    Gossip almost inevitably arises in real social networks. In this article we investigate the relationship between the number of friends of a person and limits on how far gossip about that person can spread in the network. How far gossip travels in a network depends on two sets of factors: (a) factors determining gossip transmission from one person to the next and (b) factors determining network topology. For a simple model where gossip is spread among people who know the victim it is known that a standard scale-free network model produces a non-monotonic relationship between number of friends and expected relative spread of gossip, a pattern that is also observed in real networks (Lind et al., 2007). Here, we study gossip spread in two social network models (Toivonen et al., 2006; Vázquez, 2003) by exploring the parameter space of both models and fitting them to a real Facebook data set. Both models can produce the non-monotonic relationship of real networks more accurately than a standard scale-free model while also exhibiting more realistic variability in gossip spread. Of the two models, the one given in Vázquez (2003) best captures both the expected values and variability of gossip spread.

  20. Roles of the spreading scope and effectiveness in spreading dynamics on multiplex networks

    Science.gov (United States)

    Li, Ming; Liu, Run-Ran; Peng, Dan; Jia, Chun-Xiao; Wang, Bing-Hong

    2018-02-01

    Comparing with single networks, the multiplex networks bring two main effects on the spreading process among individuals. First, the pathogen or information can be transmitted to more individuals through different layers at one time, which enlarges the spreading scope. Second, through different layers, an individual can also transmit the pathogen or information to the same individuals more than once at one time, which makes the spreading more effective. To understand the different roles of the spreading scope and effectiveness, we propose an epidemic model on multiplex networks with link overlapping, where the spreading effectiveness of each interaction as well as the variety of channels (spreading scope) can be controlled by the number of overlapping links. We find that for Poisson degree distribution, increasing the epidemic scope (the first effect) is more efficient than enhancing epidemic probability (the second effect) to facilitate the spreading process. However, for power-law degree distribution, the effects of the two factors on the spreading dynamics become complicated. Enhancing epidemic probability makes pathogen or rumor easier to outbreak in a finite system. But after that increasing epidemic scopes is still more effective for a wide spreading. Theoretical results along with reasonable explanation for these phenomena are all given in this paper, which indicates that the epidemic scope could play an important role in the spreading dynamics.

  1. Brain Arterial Diameters as a Risk Factor for Vascular Events

    OpenAIRE

    Gutierrez, Jose; Cheung, Ken; Bagci, Ahmet; Rundek, Tatjana; Alperin, Noam; Sacco, Ralph L; Wright, Clinton B; Elkind, Mitchell S V

    2015-01-01

    Background Arterial luminal diameters are routinely used to assess for vascular disease. Although small diameters are typically considered pathological, arterial dilatation has also been associated with disease. We hypothesize that extreme arterial diameters are biomarkers of the risk of vascular events. Methods and Results Participants in the Northern Manhattan Study who had a time-of-flight magnetic resonance angiography were included in this analysis (N=1034). A global arterial Z-score, ca...

  2. Investigation of debris bed formation, spreading and coolability

    Energy Technology Data Exchange (ETDEWEB)

    Kudinov, P.; Konovalenko, A.; Grishchenko, D.; Yakush, S.; Basso, S.; Lubchenko, N.; Karbojian, A. [Royal Institute of Technology, KTH. Div. of Nuclear Power Safety, Stockholm (Sweden)

    2013-08-15

    The work is motivated by the severe accident management strategy adopted in Nordic type BWRs. It is assumed that core melt ejected from the vessel will fragment, quench and form a coolable debris bed in a deep water pool below the vessel. In this work we consider phenomena relevant to the debris bed formation and coolability. Several DEFOR-A (Debris Bed Formation - Agglomeration) tests have been carried out with new corium melt material and a melt releasing nozzle mockup. The influence of the melt material, melt superheat, jet free fall height on the (i) faction of agglomerated debris, (ii) particle size distribution, (iii) ablation/plugging of the nozzle mockup has been addressed. Results of the DECOSIM (Debris Coolability Simulator) code validation against available COOLOCE data are presented in the report. The dependence of DHF on system pressure from COOLOCE experiments can be reproduced quite accurately if either the effective particle diameter or debris bed porosity is increased. For a cylindrical debris bed, good agreement is achieved in DECOSIM simulations for the particle diameter 0.89 mm and porosity 0.4. The results obtained are consistent with MEWA simulation where larger particle diameters and porosities were found to be necessary to reproduce the experimental data on DHF. It is instructive to note that results of DHF prediction are in better agreement with POMECO-HT data obtained for the same particles. It is concluded that further clarification of the discrepancies between different experiments and model predictions. In total 13 exploratory tests were carried out in PDS (particulate debris spreading) facility to clarify potential influence of the COOLOCE (VTT) facility heaters and TCs on particle self-leveling process. Results of the preliminary analysis suggest that there is no significant influence of the pins on self-leveling, at least for the air superficial velocities ranging from 0.17 up to 0.52 m/s. Further confirmatory tests might be needed

  3. Investigation of debris bed formation, spreading and coolability

    International Nuclear Information System (INIS)

    Kudinov, P.; Konovalenko, A.; Grishchenko, D.; Yakush, S.; Basso, S.; Lubchenko, N.; Karbojian, A.

    2013-08-01

    The work is motivated by the severe accident management strategy adopted in Nordic type BWRs. It is assumed that core melt ejected from the vessel will fragment, quench and form a coolable debris bed in a deep water pool below the vessel. In this work we consider phenomena relevant to the debris bed formation and coolability. Several DEFOR-A (Debris Bed Formation - Agglomeration) tests have been carried out with new corium melt material and a melt releasing nozzle mockup. The influence of the melt material, melt superheat, jet free fall height on the (i) faction of agglomerated debris, (ii) particle size distribution, (iii) ablation/plugging of the nozzle mockup has been addressed. Results of the DECOSIM (Debris Coolability Simulator) code validation against available COOLOCE data are presented in the report. The dependence of DHF on system pressure from COOLOCE experiments can be reproduced quite accurately if either the effective particle diameter or debris bed porosity is increased. For a cylindrical debris bed, good agreement is achieved in DECOSIM simulations for the particle diameter 0.89 mm and porosity 0.4. The results obtained are consistent with MEWA simulation where larger particle diameters and porosities were found to be necessary to reproduce the experimental data on DHF. It is instructive to note that results of DHF prediction are in better agreement with POMECO-HT data obtained for the same particles. It is concluded that further clarification of the discrepancies between different experiments and model predictions. In total 13 exploratory tests were carried out in PDS (particulate debris spreading) facility to clarify potential influence of the COOLOCE (VTT) facility heaters and TCs on particle self-leveling process. Results of the preliminary analysis suggest that there is no significant influence of the pins on self-leveling, at least for the air superficial velocities ranging from 0.17 up to 0.52 m/s. Further confirmatory tests might be needed

  4. Deposition of cellular fibronectin and desorption of human serum albumin during adhesion and spreading of human endothelial cells on polymers

    NARCIS (Netherlands)

    Dekker, A.; Dekker, A.; Beugeling, T.; Beugeling, T.; Wind, H.; Poot, Andreas A.; Bantjes, A.; Bantjes, A.; Feijen, Jan; van Aken, W.G.

    1991-01-01

    More insight into the mechanism of adhesion of human endothelial cells (HEC) on to polymeric surfaces may lead to the development of improved small-diameter vascular grafts. HEC suspended in 20% human serum-containing culture medium adhere and spread well on moderately water-wettable polymers such

  5. 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)

  6. 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.

  7. 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.

  8. Observation of diameter dependent carrier distribution in nanowire-based transistors

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, A; Hantschel, T; Eyben, P; Verhulst, A S; Rooyackers, R; Vandooren, A; Mody, J; Nazir, A; Leonelli, D; Vandervorst, W, E-mail: Andreas.Schulze@imec.be [IMEC, Kapeldreef 75, 3001 Leuven (Belgium)

    2011-05-06

    The successful implementation of nanowire (NW) based field-effect transistors (FET) critically depends on quantitative information about the carrier distribution inside such devices. Therefore, we have developed a method based on high-vacuum scanning spreading resistance microscopy (HV-SSRM) which allows two-dimensional (2D) quantitative carrier profiling of fully integrated silicon NW-based tunnel-FETs (TFETs) with 2 nm spatial resolution. The key elements of our characterization procedure are optimized NW cleaving and polishing steps, the use of in-house fabricated ultra-sharp diamond tips, measurements in high vacuum and a dedicated quantification procedure accounting for the Schottky-like tip-sample contact affected by surface states. In the case of the implanted TFET source regions we find a strong NW diameter dependence of conformality, junction abruptness and gate overlap, quantitatively in agreement with process simulations. In contrast, the arsenic doped drain regions reveal an unexpected NW diameter dependent dopant deactivation. The observed lower drain doping for smaller diameters is reflected in the device characteristics by lower TFET off-currents, as measured experimentally and confirmed by device simulations.

  9. Reduction of nanowire diameter beyond lithography limits by controlled catalyst dewetting

    International Nuclear Information System (INIS)

    Calahorra, Yonatan; Kerlich, Alexander; Gavrilov, Arkady; Cohen, Shimon; Ritter, Dan; Amram, Dor

    2016-01-01

    Catalyst assisted vapour-liquid–solid is the most common method to realize bottom-up nanowire growth; establishing a parallel process for obtaining nanoscale catalysts at pre-defined locations is paramount for further advancement towards commercial nanowire applications. Herein, the effect of a selective area mask on the dewetting of metallic nanowire catalysts, deposited within lithography-defined mask pinholes, is reported. It was found that thin disc-like catalysts, with diameters of 120–450 nm, were transformed through dewetting into hemisphere-like catalysts, having diameters 2–3 fold smaller; the process was optimized to about 95% yield in preventing catalyst splitting, as would otherwise be expected due to their thickness-to-diameter ratio, which was as low as 1/60. The catalysts subsequently facilitated InP and InAs nanowire growth. We suggest that the mask edges prevent surface migration mediated spreading of the dewetted metal, and therefore induce its agglomeration into a single particle. This result presents a general strategy to diminish lithography-set dimensions for NW growth, and may answer a fundamental challenge faced by bottom-up nanowire technology. (paper)

  10. Reduction of nanowire diameter beyond lithography limits by controlled catalyst dewetting

    Science.gov (United States)

    Calahorra, Yonatan; Kerlich, Alexander; Amram, Dor; Gavrilov, Arkady; Cohen, Shimon; Ritter, Dan

    2016-04-01

    Catalyst assisted vapour-liquid-solid is the most common method to realize bottom-up nanowire growth; establishing a parallel process for obtaining nanoscale catalysts at pre-defined locations is paramount for further advancement towards commercial nanowire applications. Herein, the effect of a selective area mask on the dewetting of metallic nanowire catalysts, deposited within lithography-defined mask pinholes, is reported. It was found that thin disc-like catalysts, with diameters of 120-450 nm, were transformed through dewetting into hemisphere-like catalysts, having diameters 2-3 fold smaller; the process was optimized to about 95% yield in preventing catalyst splitting, as would otherwise be expected due to their thickness-to-diameter ratio, which was as low as 1/60. The catalysts subsequently facilitated InP and InAs nanowire growth. We suggest that the mask edges prevent surface migration mediated spreading of the dewetted metal, and therefore induce its agglomeration into a single particle. This result presents a general strategy to diminish lithography-set dimensions for NW growth, and may answer a fundamental challenge faced by bottom-up nanowire technology.

  11. A network model for Ebola spreading.

    Science.gov (United States)

    Rizzo, Alessandro; Pedalino, Biagio; Porfiri, Maurizio

    2016-04-07

    The availability of accurate models for the spreading of infectious diseases has opened a new era in management and containment of epidemics. Models are extensively used to plan for and execute vaccination campaigns, to evaluate the risk of international spreadings and the feasibility of travel bans, and to inform prophylaxis campaigns. Even when no specific therapeutical protocol is available, as for the Ebola Virus Disease (EVD), models of epidemic spreading can provide useful insight to steer interventions in the field and to forecast the trend of the epidemic. Here, we propose a novel mathematical model to describe EVD spreading based on activity driven networks (ADNs). Our approach overcomes the simplifying assumption of homogeneous mixing, which is central to most of the mathematically tractable models of EVD spreading. In our ADN-based model, each individual is not bound to contact every other, and its network of contacts varies in time as a function of an activity potential. Our model contemplates the possibility of non-ideal and time-varying intervention policies, which are critical to accurately describe EVD spreading in afflicted countries. The model is calibrated from field data of the 2014 April-to-December spreading in Liberia. We use the model as a predictive tool, to emulate the dynamics of EVD in Liberia and offer a one-year projection, until December 2015. Our predictions agree with the current vision expressed by professionals in the field, who consider EVD in Liberia at its final stage. The model is also used to perform a what-if analysis to assess the efficacy of timely intervention policies. In particular, we show that an earlier application of the same intervention policy would have greatly reduced the number of EVD cases, the duration of the outbreak, and the infrastructures needed for the implementation of the intervention. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. High-temperature spreading kinetics of metals

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, N.

    2005-05-15

    In this PhD work a drop transfer setup combined with high speed photography has been used to analyze the spreading of Ag on polished polycrystalline Mo and single crystalline Mo (110) and (100) substrates. The objective of this work was to unveil the basic phenomena controlling spreading in metal-metal systems. The observed spreading kinetics were compared with current theories of low and high temperature spreading such as a molecular kinetic model and a fluid flow model. Analyses of the data reveal that the molecular model does describe the fastest velocity data well for all the investigated systems. Therefore, the energy which is dissipated during the spreading process is a dissipation at the triple line rather than dissipation due to the viscosity in the liquid. A comparison of the determined free activation energy for wetting of {delta}G95{approx}145kJ/mol with literature values allows the statement that the rate determining step seems to be a surface diffusion of the Ag atoms along the triple line. In order to investigate possible ridge formation, due to local atomic diffusion of atoms of the substrate at the triple during the spreading process, grooving experiments of the polycrystalline Mo were performed to calculate the surface diffusities that will control ridge evolution. The analyses of this work showed that a ridge formation at the fastest reported wetting velocities was not possible if there is no initial perturbation for a ridge. If there was an initial perturbation for a ridge the ridge had to be much smaller than 1 nm in order to be able to move with the liquid font. Therefore ridge formation does not influence the spreading kinetics for the studied system and the chosen conditions. SEM, AFM and TEM investigations of the triple line showed that ridge formation does also not occur at the end of the wetting experiment when the drop is close to equilibrium and the wetting velocity is slow. (orig.)

  13. Two-dimensional maximum entropy image restoration

    International Nuclear Information System (INIS)

    Brolley, J.E.; Lazarus, R.B.; Suydam, B.R.; Trussell, H.J.

    1977-07-01

    An optical check problem was constructed to test P LOG P maximum entropy restoration of an extremely distorted image. Useful recovery of the original image was obtained. Comparison with maximum a posteriori restoration is made. 7 figures

  14. Terrestrial spreading centers under Venus conditions - Evaluation of a crustal spreading model for Western Aphrodite Terra

    Science.gov (United States)

    Sotin, C.; Senske, D. A.; Head, J. W.; Parmentier, E. M.

    1989-01-01

    The model of Reid and Jackson (1981) for terrestrial spreading centers is applied to Venus conditions. On the basis of spreading rate, mantle temperature, and surface temperature, the model predicts both isostatic topography and crustal thickness. The model and Pioneer Venus altimetry and gravity data are used to test the hypothesis of Head and Crumpler (1987) that Western Aphrodite Terra is the location of crustal spreading on Venus. It is concluded that a spreading center model for Ovda Regio in Western Aphrodite Terra could account for the observed topography and line-of-sight gravity anomalies found in the Pioneer data.

  15. 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.

  16. Free energy analysis of cell spreading.

    Science.gov (United States)

    McEvoy, Eóin; Deshpande, Vikram S; McGarry, Patrick

    2017-10-01

    In this study we present a steady-state adaptation of the thermodynamically motivated stress fiber (SF) model of Vigliotti et al. (2015). We implement this steady-state formulation in a non-local finite element setting where we also consider global conservation of the total number of cytoskeletal proteins within the cell, global conservation of the number of binding integrins on the cell membrane, and adhesion limiting ligand density on the substrate surface. We present a number of simulations of cell spreading in which we consider a limited subset of the possible deformed spread-states assumed by the cell in order to examine the hypothesis that free energy minimization drives the process of cell spreading. Simulations suggest that cell spreading can be viewed as a competition between (i) decreasing cytoskeletal free energy due to strain induced assembly of cytoskeletal proteins into contractile SFs, and (ii) increasing elastic free energy due to stretching of the mechanically passive components of the cell. The computed minimum free energy spread area is shown to be lower for a cell on a compliant substrate than on a rigid substrate. Furthermore, a low substrate ligand density is found to limit cell spreading. The predicted dependence of cell spread area on substrate stiffness and ligand density is in agreement with the experiments of Engler et al. (2003). We also simulate the experiments of Théry et al. (2006), whereby initially circular cells deform and adhere to "V-shaped" and "Y-shaped" ligand patches. Analysis of a number of different spread states reveals that deformed configurations with the lowest free energy exhibit a SF distribution that corresponds to experimental observations, i.e. a high concentration of highly aligned SFs occurs along free edges, with lower SF concentrations in the interior of the cell. In summary, the results of this study suggest that cell spreading is driven by free energy minimization based on a competition between decreasing

  17. Spreading paths in partially observed social networks

    Science.gov (United States)

    Onnela, Jukka-Pekka; Christakis, Nicholas A.

    2012-03-01

    Understanding how and how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading paths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using static, structurally realistic social networks as platforms for simulations, we juxtapose three distinct paths: (1) the stochastic path taken by a simulated spreading process from source to target; (2) the topologically shortest path in the fully observed network, and hence the single most likely stochastic path, between the two nodes; and (3) the topologically shortest path in a partially observed network. In a sampled network, how closely does the partially observed shortest path (3) emulate the unobserved spreading path (1)? Although partial observation inflates the length of the shortest path, the stochastic nature of the spreading process also frequently derails the dynamic path from the shortest path. We find that the partially observed shortest path does not necessarily give an inflated estimate of the length of the process path; in fact, partial observation may, counterintuitively, make the path seem shorter than it actually is.

  18. Spreading paths in partially observed social networks.

    Science.gov (United States)

    Onnela, Jukka-Pekka; Christakis, Nicholas A

    2012-03-01

    Understanding how and how far information, behaviors, or pathogens spread in social networks is an important problem, having implications for both predicting the size of epidemics, as well as for planning effective interventions. There are, however, two main challenges for inferring spreading paths in real-world networks. One is the practical difficulty of observing a dynamic process on a network, and the other is the typical constraint of only partially observing a network. Using static, structurally realistic social networks as platforms for simulations, we juxtapose three distinct paths: (1) the stochastic path taken by a simulated spreading process from source to target; (2) the topologically shortest path in the fully observed network, and hence the single most likely stochastic path, between the two nodes; and (3) the topologically shortest path in a partially observed network. In a sampled network, how closely does the partially observed shortest path (3) emulate the unobserved spreading path (1)? Although partial observation inflates the length of the shortest path, the stochastic nature of the spreading process also frequently derails the dynamic path from the shortest path. We find that the partially observed shortest path does not necessarily give an inflated estimate of the length of the process path; in fact, partial observation may, counterintuitively, make the path seem shorter than it actually is.

  19. Assessment of thema code against spreading experiments

    International Nuclear Information System (INIS)

    Spindler, B.; Veteau, J.M.; Cecco, L. de; Montanelli, P.; Pineau, D.

    2000-01-01

    In the frame work of severe accident research, the spreading code THEMA, developed at CEA/DRN, aims at predicting the spreading extent of molten core after a vessel melt-through. The code solves fluid balance equations integrated over the fluid depth for oxidic and/or metallic phases under the shallow water assumption, using a finite difference scheme. Solidification is taken into account through crust formation on the substrate and at contact with the surroundings, as well as increase of fluid viscosity with solid fraction in the melt. A separate energy equation is solved for the solid substrate, including possible ablation. The assessment of THEMA code against the spreading experiments performed in the framework of the corium spreading and coolability project of the European Union is presented. These experiments use either simulating materials at medium (RIT), or at high temperature (KATS), or corium (VULCANO, FARO), conducted at different mass flow rates and with large or low solidification interval. THEMA appears to be able to simulate the whole set of the experiments investigated. Comparison between experimental and computed spreading lengths and substrate temperatures are quite satisfactory. The results show a rather large sensitivity at mass flow rate and inlet temperature, indicating that, generally, efforts should be made to improve the accuracy of the measurements of such parameters in the experiments. (orig.)

  20. Post-Tanner spreading of nematic droplets

    International Nuclear Information System (INIS)

    Mechkov, S; Oshanin, G; Cazabat, A M

    2009-01-01

    The quasistationary spreading of a circular liquid drop on a solid substrate typically obeys the so-called Tanner law, with the instantaneous base radius R(t) growing with time as R∼t 1/10 -an effect of the dominant role of capillary forces for a small-sized droplet. However, for droplets of nematic liquid crystals, a faster spreading law sets in at long times, so that R∼t α with α significantly larger than the Tanner exponent 1/10. In the framework of the thin film model (or lubrication approximation), we describe this 'acceleration' as a transition to a qualitatively different spreading regime driven by a strong substrate-liquid interaction specific to nematics (antagonistic anchoring at the interfaces). The numerical solution of the thin film equation agrees well with the available experimental data for nematics, even though the non-Newtonian rheology has yet to be taken into account. Thus we complement the theory of spreading with a post-Tanner stage, noting that the spreading process can be expected to cross over from the usual capillarity-dominated stage to a regime where the whole reservoir becomes a diffusive film in the sense of Derjaguin.

  1. Diameter dependence of emission power in MgO-based nano-pillar spin-torque oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Bochong; Kubota, Hitoshi, E-mail: hit-kubota@aist.go.jp; Yakushiji, Kay; Tamaru, Shingo; Arai, Hiroko; Imamura, Hiroshi; Fukushima, Akio; Yuasa, Shinji [Spintronics Research Center, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki 305-8568 (Japan)

    2016-06-20

    The dependence on diameter of the emission power in MgO-based nano-pillar spin torque oscillators (STOs) was systematically investigated. A maximum emission power of over 2.5 μW was obtained around 300 nm in diameter, which is the largest reported to date among the out-of-plane precession STOs. By analyzing physical quantities, precession cone angle of the free-layer magnetization was evaluated. In the diameter range below 300 nm, the increase in power was mainly due to the increase of the injected current. The power decrease above 300 nm is possibly attributed to the decrease in the averaged precession cone angle, suggesting spatial phase difference of magnetization precession. This study provides the method for estimating the optimum STO diameter, which is of great importance in practical use.

  2. Influence of high intensity ultrasound with different probe diameter ...

    African Journals Online (AJOL)

    The main goal of this research is to analyze the influence of ultrasonic probe diameters (7 and 10 mm) of high-intensity ultrasound with constant frequency (30 kHz) on the degree of homogenization (variance) of cow milk. Influence of different probe diameters on the physical properties of cow milk was also tested. Changes ...

  3. Lumbar Vertebral Canal Diameters in Adult Ugandan Skeletons ...

    African Journals Online (AJOL)

    Background: Normal values of lumbar vertebral canal diameters are useful in facilitating diagnosis of lumbar vertebral canal stenosis. Various studies have established variation on values between different populations, gender, age, and ethnic groups. Objectives: To determine the lumbar vertebral canal diameters in adult ...

  4. Relationships between diameter and height of trees in natural ...

    African Journals Online (AJOL)

    Relationships between diameter and height of trees in natural tropical forest in Tanzania. Wilson A Mugasha, Ole M Bollandsås, Tron Eid. Abstract. The relationship between tree height (h) and tree diameter at breast height (dbh) is an important element describing forest stands. In addition, h often is a required variable in ...

  5. Heritability of optic disc diameters: a twin study

    DEFF Research Database (Denmark)

    Drobnjak, Dragana; Taarnhøj, Nina Charlotte; Mitchell, Paul

    2011-01-01

    , additive genetic factors (i.e. heritability) explained 77% (95% CI: 65-85%) of variation of vertical disc diameters, whereas estimated unshared environmental effect was 23% (95% CI: 15-35%). For vertical cup diameters, heritability accounted for 70% (95% CI: 55-80%) and environmental factors 30% (95% CI...

  6. Diameter of the thoracic and abdominal aorta in healthy Japanese

    International Nuclear Information System (INIS)

    Matsunaga, Wakako

    1989-01-01

    In 300 cases, diameter of thoracic and abdominal aorta in healthy Japanese is measured by computed tomography (CT) and the values are analyzed in relation to the age, sex and the level of the aorta on CT scan. Aorta becomes dilated with age. In female diameter of the aorta is correlated with age, on the other hand, diameter of those is not correlated with age in male. Diameter in male is larger than in female. Aorta tapers off and the ratio of tapering of the thoracic aorta is more prominent than that of the abdominal aorta. Therefore the calculations of the landmarks of tapering of the aorta and the ratio of diameter of the aorta to transverse diameter of the vertebral body at the levels of 10th thoracic and 3rd lumber vertebrae on CT scan are useful for judgement of normal range of diameter of the aorta. Calcifications of the wall of the aorta are seen initially at the age of 5th decade in the abdominal aorta and 6th decade in the thoracic aorta in healthy Japanese. They are noted in almost of the persons after the age of seventy years old. The presence of calcification is not correlated with diameter of the aorta at the same level on CT scan. (author)

  7. Generalized height-diameter models for Populus tremula L. stands

    African Journals Online (AJOL)

    USER

    2010-07-12

    Jul 12, 2010 ... and stand density) into the base height-diameter models increased the accuracy of prediction for P. tremula. .... parameter estimates compared with those obtained with ... using coefficient of determination for non-linear regression (. 2. R ), ..... stochastic height-diameter model for maritime pine ecoregions in.

  8. Sex Dimorphism of the Heart Diameters and Cardiothoracic Ratios ...

    African Journals Online (AJOL)

    Objective: To determine gender associated differences in the cardiothoracic ratio (CTR) and heart diameters in a normal Nigerian population. Subject and Method: The normal heart diameters and cardiothoracic ratios were measured from posteroanterior (PA) chest radiographs of healthy 510 male and 508 female ...

  9. 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

  10. Receiver function estimated by maximum entropy deconvolution

    Institute of Scientific and Technical Information of China (English)

    吴庆举; 田小波; 张乃铃; 李卫平; 曾融生

    2003-01-01

    Maximum entropy deconvolution is presented to estimate receiver function, with the maximum entropy as the rule to determine auto-correlation and cross-correlation functions. The Toeplitz equation and Levinson algorithm are used to calculate the iterative formula of error-predicting filter, and receiver function is then estimated. During extrapolation, reflective coefficient is always less than 1, which keeps maximum entropy deconvolution stable. The maximum entropy of the data outside window increases the resolution of receiver function. Both synthetic and real seismograms show that maximum entropy deconvolution is an effective method to measure receiver function in time-domain.

  11. Diffusive spreading in nature, technology and society

    CERN Document Server

    Caro, Jürgen; Kärger, Jörg; Vogl, Gero

    2018-01-01

    This book deals with randomly moving objects and their spreading. The objects considered are particles like atoms and molecules, just as living beings like humans, animals, plants, bacteria and even abstract entities like ideas, rumors, information, innovations and linguistic features. The book explores and communicates the laws behind these movements and reports about astonishing similarities and very specific features typical of the given object under considerations. Leading scientists in disciplines as different as archeology, epidemics, linguistics and sociology, in contact with their colleagues from engineering, natural sciences and mathematics, introduce into the phenomena of spreading as relevant for their fields. An introductory chapter on “Spreading Fundamentals” provides a common basis for all these considerations, with a minimum of mathematics, selected and presented for enjoying rather than frustrating the reader.

  12. Linear theory of equatorial spread F

    International Nuclear Information System (INIS)

    Hudson, M.K.; Kennel, C.F.

    1975-01-01

    A fluid dispersion relation for the drift and interchange (Rayleigh-Taylor) modes in a collisional plasma forms the basis for a linear theory of equatorial spread F. The collisional drift mode growth rate will exceed the growth rate of the Rayleigh-Taylor mode at short perpendicular wavelengths and density gradient scale lengths, and the drift mode can grow on top side as well as on bottom side density gradients. However, below the F peak, where spread F predominates, it is concluded that both the drift and the Rayleigh-Taylor modes contribute to the total spread F spectrum, the Rayleigh-Taylor mode dominating at long and the drift mode at short perpendicular wavelengths above the ion Larmor radius

  13. Does pan diameter influence carbon monoxide levels during heating of water to boiling point with a camping stove?

    Science.gov (United States)

    Leigh-Smith, Simon; Stevenson, Richard; Watt, Martin; Watt, Ian; McFadyen, Angus; Grant, Stan

    2004-01-01

    To determine whether pan diameter influences carbon monoxide (CO) concentration during heating of water to boiling point with a camping stove. The hypothesis was that increasing pan diameter increases CO concentration because of greater flame dispersal and a larger flame. This was a randomized, prospective study. A Coleman Dual Fuel 533 stove was used to heat pans of water to boiling point, with CO concentration monitored every 30 seconds for 5 minutes. The stove was inside a partially ventilated 200-L cardboard box model that was inside an environmental chamber at -6 degrees C. Water temperature, water volume, and flame characteristics were all standardized. Ten trials were performed for each of 2 pan diameters (base diameters of 165 mm [small] and 220 mm [large]). There was a significant difference (P = .002) between the pans for CO levels at each measurement interval from 60 seconds onward. These differences were markedly larger after 90 seconds, with a mean difference of 185 ppm (95% CI 115, 276 ppm) for all the results from 120 seconds onwards. This study has shown that there is significantly higher CO production with a large-diameter pan compared with a small-diameter pan. These findings were evident by using a camping stove to heat water to boiling point when a maximum blue flame was present throughout. Thus, in enclosed environments it is recommended that small-diameter pans be used in an attempt to prevent high CO levels.

  14. Maximum Power from a Solar Panel

    Directory of Open Access Journals (Sweden)

    Michael Miller

    2010-01-01

    Full Text Available Solar energy has become a promising alternative to conventional fossil fuel sources. Solar panels are used to collect solar radiation and convert it into electricity. One of the techniques used to maximize the effectiveness of this energy alternative is to maximize the power output of the solar collector. In this project the maximum power is calculated by determining the voltage and the current of maximum power. These quantities are determined by finding the maximum value for the equation for power using differentiation. After the maximum values are found for each time of day, each individual quantity, voltage of maximum power, current of maximum power, and maximum power is plotted as a function of the time of day.

  15. A model for multiseasonal spread of verticillium wilt of lettuce.

    Science.gov (United States)

    Wu, B M; Subbarao, K V

    2014-09-01

    Verticillium wilt, caused by Verticillium dahliae, is a destructive disease in lettuce, and the pathogen is seedborne. Even though maximum seed infestation rates of lettuce seed lots, it is necessary to establish acceptable contamination thresholds to prevent introduction and establishment of the pathogen in lettuce production fields. However, introduction of inoculum into lettuce fields for experimental purposes to determine its long term effects is undesirable. Therefore, we constructed a simulation model to study the spread of Verticillium wilt following pathogen introduction from seed. The model consists of four components: the first for simulating infection of host plants, the second for simulating reproduction of microsclerotia on diseased plants, the third for simulating the survival of microsclerotia, and the fourth for simulating the dispersal of microsclerotia. The simulation results demonstrated that the inoculum density-disease incidence curve parameters and the dispersal gradients affect disease spread in the field. Although a steep dispersal gradient facilitated the establishment of the disease in a new field with a low inoculum density, a long-tail gradient allowed microsclerotia to be dispersed over greater distances, promoting the disease spread in fields with high inoculum density. The simulation results also revealed the importance of avoiding successive lettuce crops in the same field, reducing survival rate of microsclerotia between crops, and the need for breeding resistance against V. dahliae in lettuce cultivars to lower the number of microsclerotia formed on each diseased plant. The simulation results, however, suggested that, even with a low seed infestation rate, the pathogen would eventually become established if susceptible lettuce cultivars were grown consecutively in the same field for many years. A threshold for seed infestation can be established only when two of the three drivers of the disease-(i) low microsclerotia production per

  16. Residual stress improved by water jet peening using cavitation for small-diameter pipe inner surfaces

    International Nuclear Information System (INIS)

    Yasuo, Nakamura; Toshizo, Ohya; Koji, Okimura

    2001-01-01

    As one of degradation conditions on components used in water, the overlapping effect of environment, material and stress might cause stress corrosion cracking (SCC). Especially, for the tensile residual stress produced by welding, it is particularly effective to reduce the tensile residual stress on the material surface to prevent SCC. In this paper, the residual stress improvement method using cavitation impact generated by a water jet, called Water Jet Peening (WJP), has been developed as the maintenance technology for the inner surfaces of small-diameter Ni-Cr-Fe alloy (Alloy 600) pipes. As the results, by WJP for the inner surface of Alloy 600 pipe (inner diameter; approximately 10-15 mm), we confirmed that the compressive stress generated within the range from the surface to the inner part about 0.5 mm deep and took a maximum value about 350 MPa on the surface. (author)

  17. Design method of large-diameter rock-socketed pile with steel casing

    Science.gov (United States)

    Liu, Ming-wei; Fang, Fang; Liang, Yue

    2018-02-01

    There is a lack of the design and calculation method of large-diameter rock-socketed pile with steel casing. Combined with the “twelfth five-year plan” of the National Science & Technology Pillar Program of China about “Key technologies on the ports and wharfs constructions of the mountain canalization channels”, this paper put forward the structured design requirements of concrete, steel bar distribution and steel casing, and a checking calculation method of the bearing capacity of the normal section of the pile and the maximum crack width at the bottom of the steel casing. The design method will have some degree of guiding significance for the design of large-diameter rock-socketed pile with steel casing.

  18. Turbulent forces within river plumes affect spread

    Science.gov (United States)

    Bhattacharya, Atreyee

    2012-08-01

    When rivers drain into oceans through narrow mouths, hydraulic forces squeeze the river water into buoyant plumes that are clearly visible in satellite images. Worldwide, river plumes not only disperse freshwater, sediments, and nutrients but also spread pollutants and organisms from estuaries into the open ocean. In the United States, the Columbia River—the largest river by volume draining into the Pacific Ocean from North America—generates a plume at its mouth that transports juvenile salmon and other fish into the ocean. Clearly, the behavior and spread of river plumes, such as the Columbia River plume, affect the nation's fishing industry as well as the global economy.

  19. The spread of gossip in American schools

    Science.gov (United States)

    Lind, P. G.; da Silva, L. R.; Andrade, J. S., Jr.; Herrmann, H. J.

    2007-06-01

    Gossip is defined as a rumor which specifically targets one individual and essentially only propagates within its friendship connections. How fast and how far a gossip can spread is for the first time assessed quantitatively in this study. For that purpose we introduce the "spread factor" and study it on empirical networks of school friendships as well as on various models for social connections. We discover that there exists an ideal number of friendship connections an individual should have to minimize the danger of gossip propagation.

  20. Can rewiring strategy control the epidemic spreading?

    Science.gov (United States)

    Dong, Chao; Yin, Qiuju; Liu, Wenyang; Yan, Zhijun; Shi, Tianyu

    2015-11-01

    Relation existed in the social contact network can affect individuals' behaviors greatly. Considering the diversity of relation intimacy among network nodes, an epidemic propagation model is proposed by incorporating the link-breaking threshold, which is normally neglected in the rewiring strategy. The impact of rewiring strategy on the epidemic spreading in the weighted adaptive network is explored. The results show that the rewiring strategy cannot always control the epidemic prevalence, especially when the link-breaking threshold is low. Meanwhile, as well as strong links, weak links also play a significant role on epidemic spreading.

  1. Proper Analytic Point Spread Function for Lateral Modulation

    Science.gov (United States)

    Sumi, Chikayoshi; Shimizu, Kunio; Matsui, Norihiko

    2010-07-01

    For ultrasonic lateral modulation for the imaging and measurement of tissue motion, better envelope shapes of the point spread function (PSF) than of a parabolic function are searched for within analytic functions or windows on the basis of the knowledge of the ideal shape of PSF previously obtained, i.e., having a large full width at half maximum and short feet. Through simulation of displacement vector measurement, better shapes are determined. As a better shape, a new window is obtained from a Turkey window by changing Hanning windows by power functions with an order larger than the second order. The order of measurement accuracies obtained is as follows, the new window > rectangular window > power function with a higher order > parabolic function > Akaike window.

  2. Low energy intense electron beams with extra-low energy spread

    International Nuclear Information System (INIS)

    Aleksandrov, A.V.; Calabrese, R.; Ciullo, G.; Dikansky, N.S.; Guidi, V.; Kot, N.C.; Kudelainen, V.I.; Lamanna, G.; Lebedev, V.A.; Logachov, P.V.; Tecchio, L.; Yang, B.

    1994-01-01

    Maximum achievable intensity for low energy electron beams is a feature that is not very often compatible with low energy spread. We show that a proper choice of the source and the acceleration optics allows one to match them together. In this scheme, a GaAs photocathode excited by a single-mode infrared laser and adiabatic acceleration in fully magnetised optics enables the production of a low-energy-spread electron beam with relatively high intensity. The technological problems associated with the method are discussed together with its limitations. (orig.)

  3. 40 CFR 1054.140 - What is my engine's maximum engine power and displacement?

    Science.gov (United States)

    2010-07-01

    ... internal diameter of 6.00 cm and a 6.25 cm stroke length, the rounded displacement would be: (1) × (6.00/2... power and displacement? 1054.140 Section 1054.140 Protection of Environment ENVIRONMENTAL PROTECTION... engine power and displacement? This section describes how to quantify your engine's maximum engine power...

  4. PROFIT-PC: a program for estimating maximum net revenue from multiproduct harvests in Appalachian hardwoods

    Science.gov (United States)

    Chris B. LeDoux; John E. Baumgras; R. Bryan Selbe

    1989-01-01

    PROFIT-PC is a menu driven, interactive PC (personal computer) program that estimates optimum product mix and maximum net harvesting revenue based on projected product yields and stump-to-mill timber harvesting costs. Required inputs include the number of trees/acre by species and 2 inches diameter at breast-height class, delivered product prices by species and product...

  5. Indirect and direct methods for measuring a dynamic throat diameter in a solid rocket motor

    Science.gov (United States)

    Colbaugh, Lauren

    In a solid rocket motor, nozzle throat erosion is dictated by propellant composition, throat material properties, and operating conditions. Throat erosion has a significant effect on motor performance, so it must be accurately characterized to produce a good motor design. In order to correlate throat erosion rate to other parameters, it is first necessary to know what the throat diameter is throughout a motor burn. Thus, an indirect method and a direct method for determining throat diameter in a solid rocket motor are investigated in this thesis. The indirect method looks at the use of pressure and thrust data to solve for throat diameter as a function of time. The indirect method's proof of concept was shown by the good agreement between the ballistics model and the test data from a static motor firing. The ballistics model was within 10% of all measured and calculated performance parameters (e.g. average pressure, specific impulse, maximum thrust, etc.) for tests with throat erosion and within 6% of all measured and calculated performance parameters for tests without throat erosion. The direct method involves the use of x-rays to directly observe a simulated nozzle throat erode in a dynamic environment; this is achieved with a dynamic calibration standard. An image processing algorithm is developed for extracting the diameter dimensions from the x-ray intensity digital images. Static and dynamic tests were conducted. The measured diameter was compared to the known diameter in the calibration standard. All dynamic test results were within +6% / -7% of the actual diameter. Part of the edge detection method consists of dividing the entire x-ray image by an average pixel value, calculated from a set of pixels in the x-ray image. It was found that the accuracy of the edge detection method depends upon the selection of the average pixel value area and subsequently the average pixel value. An average pixel value sensitivity analysis is presented. Both the indirect

  6. 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....

  7. 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.

  8. 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.

  9. Brain Arterial Diameters as a Risk Factor for Vascular Events.

    Science.gov (United States)

    Gutierrez, Jose; Cheung, Ken; Bagci, Ahmet; Rundek, Tatjana; Alperin, Noam; Sacco, Ralph L; Wright, Clinton B; Elkind, Mitchell S V

    2015-08-06

    Arterial luminal diameters are routinely used to assess for vascular disease. Although small diameters are typically considered pathological, arterial dilatation has also been associated with disease. We hypothesize that extreme arterial diameters are biomarkers of the risk of vascular events. Participants in the Northern Manhattan Study who had a time-of-flight magnetic resonance angiography were included in this analysis (N=1034). A global arterial Z-score, called the brain arterial remodeling (BAR) score, was obtained by averaging the measured diameters within each individual. Individuals with a BAR score -2 and 2 SDs had the largest diameters. All vascular events were recorded prospectively after the brain magnetic resonance imaging. Spline curves and incidence rates were used to test our hypothesis. The association of the BAR score with death (P=0.001), vascular death (P=0.02), any vascular event (P=0.05), and myocardial infarction (P=0.10) was U-shaped except for ischemic stroke (P=0.74). Consequently, incidence rates for death, vascular death, myocardial infarction, and any vascular event were higher in individuals with the largest diameters, whereas individuals with the smallest diameters had a higher incidence of death, vascular death, any vascular event, and ischemic stroke compared with individuals with average diameters. The risk of death, vascular death, and any vascular event increased at both extremes of brain arterial diameters. The pathophysiology linking brain arterial remodeling to systemic vascular events needs further research. © 2015 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

  10. 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.

  11. Production of low axial energy spread ion beams with multicusp sources

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yung -Hee Y. [Univ. of California, Berkeley, CA (United States)

    1998-05-01

    Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution.

  12. Production of low axial energy spread ion beams with multicusp sources

    International Nuclear Information System (INIS)

    Lee, Y.H.Y.

    1998-05-01

    Multicusp ion sources are capable of producing ions with low axial energy spread which are necessary in applications such as: ion projection lithography (IPL) and focused ion beams for the next generation lithographic tools and nuclear science experiments such as radioactive ion beam production. The axial ion energy spread for multicusp source is approximately 6 eV which is too large for IPL and radioactive ion beam applications. The addition of a magnetic filter which consists of a pair of permanent magnets to the multicusp source reduces the energy spread considerably. The reduction is due to the improvement in the uniformity of the axial plasma potential distribution in the discharge region. Axial ion energy spread of the filament driven ion source has been measured using three different techniques. In all cases, it was found to be less than 2 eV. Energy spread of the radio frequency (RF) driven source has also been explored, and it was found to be less than 3 eV with the proper RF-shielding. A new multicusp source configuration has been designed and constructed to further reduce the energy spread. To achieve a more uniform axial plasma potential distribution, a cylindrical magnetic filter has been designed and constructed for a 2-cm-diameter source. This new source configuration, the co-axial source, is new in its kind. The energy spread in this source has been measured to be a record low of 0.6 eV. Because of the novelty of this device, some plasma parameters inside the source have been studied. Langmuir probe has been used to measure the plasma potential, the electron temperature and the density distribution

  13. Evaluating Maximum Wind Energy Exploitation in Active Distribution Networks

    DEFF Research Database (Denmark)

    Siano, Pierluigi; Chen, Peiyuan; Chen, Zhe

    2010-01-01

    The increased spreading of distributed and renewable generation requires moving towards active management of distribution networks. In this paper, in order to evaluate maximum wind energy exploitation in active distribution networks, a method based on a multi-period optimal power flow (OPF......) analysis is proposed. Active network management schemes such as coordinated voltage control, energy curtailment and power factor control are integrated in the method in order to investigate their impacts on the maximization of wind energy exploitation. Some case studies, using real data from a Danish...... distribution system, confirmed the effectiveness of the proposed method in evaluating the optimal applications of active management schemes to increase wind energy harvesting without costly network reinforcement for the connection of wind generation....

  14. Reduced arterial diameter during static exercise in humans

    DEFF Research Database (Denmark)

    Olesen, H L; Mitchell, J H; Friedman, D B

    1995-01-01

    In eight subjects luminal diameter of the resting limb radial and dorsalis pedis arteries was determined by high-resolution ultrasound (20 MHz). This measurement was followed during rest and during 2 min of static handgrip or of one-leg knee extension at 30% of maximal voluntary contraction...... exertion was approximately 15 units after both types of exercise. The dorsalis pedis arterial diameter was 1.50 +/- 0.20 mm (mean and SE) and the radial AD 2.45 +/- 0.12 mm. During both types of contractions the luminal diameters decreased approximately 3.5% within the first 30 s (P

  15. 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.

  16. Experiments on non-isothermal spreading

    International Nuclear Information System (INIS)

    Ehrhard, P.

    1992-09-01

    Experiments are performed on axisymmetric spreading of viscous drops on glass plates. Two liquids are investigated: silicone oil (M-100) spreads to 'infinity' and paraffin oil spreads to a finite-radius steady state. The experiments with silicone oil partly recover the behaviour of previous workers data; those experiments with paraffin oil provide new data. It is found that gravitational forces dominate at long enough times while at shorter times capillary forces dominate. When the plate is heated or cooled with respect to the ambient gas, thermocapillary forces generate flows that alter the spreading dynamics. Heating (cooling) the plate is found to retard (augment) the streading. Moreover, in case of partial wetting, the finally-approached drop radius is smaller (larger) for a heated (cooled) plate. These data are all new. All these observations are in excellent quantitative agreement with the related model predictions of Ehrhard and Davis (1991). A breakdown of the axisymmetric character of the flow is observed only for very long times and/or very thin liquid layers. (orig.) [de

  17. Social Distancing Strategies against Disease Spreading

    Science.gov (United States)

    Valdez, L. D.; Buono, C.; Macri, P. A.; Braunstein, L. A.

    2013-12-01

    The recurrent infectious diseases and their increasing impact on the society has promoted the study of strategies to slow down the epidemic spreading. In this review we outline the applications of percolation theory to describe strategies against epidemic spreading on complex networks. We give a general outlook of the relation between link percolation and the susceptible-infected-recovered model, and introduce the node void percolation process to describe the dilution of the network composed by healthy individual, i.e., the network that sustain the functionality of a society. Then, we survey two strategies: the quenched disorder strategy where an heterogeneous distribution of contact intensities is induced in society, and the intermittent social distancing strategy where health individuals are persuaded to avoid contact with their neighbors for intermittent periods of time. Using percolation tools, we show that both strategies may halt the epidemic spreading. Finally, we discuss the role of the transmissibility, i.e., the effective probability to transmit a disease, on the performance of the strategies to slow down the epidemic spreading.

  18. Disease spreading in real-life networks

    Science.gov (United States)

    Gallos, Lazaros; Argyrakis, Panos

    2002-08-01

    In recent years the scientific community has shown a vivid interest in the network structure and dynamics of real-life organized systems. Many such systems, covering an extremely wide range of applications, have been recently shown to exhibit scale-free character in their connectivity distribution, meaning that they obey a power law. Modeling of epidemics on lattices and small-world networks suffers from the presence of a critical infection threshold, above which the entire population is infected. For scale-free networks, the original assumption was that the formation of a giant cluster would lead to an epidemic spreading in the same way as in simpler networks. Here we show that modeling epidemics on a scale-free network can greatly improve the predictions on the rate and efficiency of spreading, as compared to lattice models and small-world networks. We also show that the dynamics of a disease are greatly influenced by the underlying population structure. The exact same model can describe a plethora of networks, such as social networks, virus spreading in the Web, rumor spreading, signal transmission etc.

  19. Spread of Rare Fungus from Vancouver Island

    Centers for Disease Control (CDC) Podcasts

    2006-12-20

    Cryptococcus gattii, a rare fungus normally found in the tropics, has infected people and animals on Vancouver Island, Canada. Dr. David Warnock, Director, Division of Foodborne, Bacterial, and Mycotic Diseases, CDC, discusses public health concerns about further spread of this organism.  Created: 12/20/2006 by Emerging Infectious Diseases.   Date Released: 12/29/2006.

  20. DataSpread: Unifying Databases and Spreadsheets.

    Science.gov (United States)

    Bendre, Mangesh; Sun, Bofan; Zhang, Ding; Zhou, Xinyan; Chang, Kevin ChenChuan; Parameswaran, Aditya

    2015-08-01

    Spreadsheet software is often the tool of choice for ad-hoc tabular data management, processing, and visualization, especially on tiny data sets. On the other hand, relational database systems offer significant power, expressivity, and efficiency over spreadsheet software for data management, while lacking in the ease of use and ad-hoc analysis capabilities. We demonstrate DataSpread, a data exploration tool that holistically unifies databases and spreadsheets. It continues to offer a Microsoft Excel-based spreadsheet front-end, while in parallel managing all the data in a back-end database, specifically, PostgreSQL. DataSpread retains all the advantages of spreadsheets, including ease of use, ad-hoc analysis and visualization capabilities, and a schema-free nature, while also adding the advantages of traditional relational databases, such as scalability and the ability to use arbitrary SQL to import, filter, or join external or internal tables and have the results appear in the spreadsheet. DataSpread needs to reason about and reconcile differences in the notions of schema, addressing of cells and tuples, and the current "pane" (which exists in spreadsheets but not in traditional databases), and support data modifications at both the front-end and the back-end. Our demonstration will center on our first and early prototype of the DataSpread, and will give the attendees a sense for the enormous data exploration capabilities offered by unifying spreadsheets and databases.

  1. Unidirectional spreading of oil under solid ice

    International Nuclear Information System (INIS)

    Weerasuriya, S.A.; Yapa, P.D.

    1993-01-01

    Equations are presented to describe the unidirectional spreading of oil under solid ice covers floating in calm water. These spreading equations are derived using a simplified form of the Navier-Stokes equations, and cover both the constant discharge and the constant volume modes. An equation for computing final slick length is also given. Laboratory experiments using physical models were conducted to verify the equations. The experiments used oils of different viscosities, ice cover roughnesses varying from smooth to rough, and a variety of discharge conditions. The emphasis of the study was on the dominant spreading mechanism for oil under ice, which is the buoyancy-viscous phase. The laboratory results agree closely with the theoretical predictions. Discrepancies can be attributed to the experimental difficulties and errors introduced from the assumptions made in deriving the theory. The equations presented will be useful in computing spreading rate during an accidental oil spill or in contingency planning. The equations are simple to use, suitable for hand calculations or for incorporation into numerical models for oil spill simulation. 24 refs., 10 figs., 1 tab

  2. Modelling of fire spread in car parks

    NARCIS (Netherlands)

    Noordijk, L.M.; Lemaire, A.D.

    2005-01-01

    Currently, design codes assume that in a car park fire at most 3-4 vehicles are on fire at the same time. Recent incidents in car parks have drawn international attention to such assumptions and have raised questions as to the fire spreading mechanism and the resulting fire load on the structure.

  3. Spread of Rare Fungus from Vancouver Island

    Centers for Disease Control (CDC) Podcasts

    Cryptococcus gattii, a rare fungus normally found in the tropics, has infected people and animals on Vancouver Island, Canada. Dr. David Warnock, Director, Division of Foodborne, Bacterial, and Mycotic Diseases, CDC, discusses public health concerns about further spread of this organism

  4. Energy spread in ion beam analysis

    International Nuclear Information System (INIS)

    Szilagyi, E.

    2000-01-01

    In ion beam analysis (IBA) the depth profiles are extracted from the experimentally determined energy profiles. The spectra, however, are subject to finite energy resolution of both extrinsic and intrinsic origin. Calculation of those effects such as instrumental beam, geometry and detection-related energy and angular spreads as well as energy straggling, multiple scattering and Doppler effects in the sample itself is not trivial, especially since it involves treatment of non-independent random processes. A proper account for energy spread is vital in IBA not only for correct extraction of elemental and isotopic depth profiles from the measured spectra, but already prior to data acquisition, in optimising experimental conditions to reach the required depth resolution at a certain depth. After a short review of the literature on the different energy spread contributions experimental examples are given from resonance, RBS, elastic BS and ERDA practice in which an account for energy spread contributions is essential. Some further examples illustrate extraction of structural information (roughness, pore size, etc.) from elaborated depth resolution calculation for such layer structures

  5. Energy spread in ion beam analysis

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, E. E-mail: szilagyi@rmki.kkfki.hu

    2000-03-01

    In ion beam analysis (IBA) the depth profiles are extracted from the experimentally determined energy profiles. The spectra, however, are subject to finite energy resolution of both extrinsic and intrinsic origin. Calculation of those effects such as instrumental beam, geometry and detection-related energy and angular spreads as well as energy straggling, multiple scattering and Doppler effects in the sample itself is not trivial, especially since it involves treatment of non-independent random processes. A proper account for energy spread is vital in IBA not only for correct extraction of elemental and isotopic depth profiles from the measured spectra, but already prior to data acquisition, in optimising experimental conditions to reach the required depth resolution at a certain depth. After a short review of the literature on the different energy spread contributions experimental examples are given from resonance, RBS, elastic BS and ERDA practice in which an account for energy spread contributions is essential. Some further examples illustrate extraction of structural information (roughness, pore size, etc.) from elaborated depth resolution calculation for such layer structures.

  6. Population Movement and Virus Spreading: HEV Spreading in a Pilgrimage City, Mashhad in Northeast Iran; an Example.

    Science.gov (United States)

    Ahmadi Ghezeldasht, Sanaz; Miri, Rahele; Hedayatimoghadam, Mohamadreza; Shamsian, Aliakbar; Bidkhori, Hamidreza; Fathimoghadam, Fahad; Rezaee, Seyyed Abdorrahim

    2013-01-01

    Hepatitis E Virus (HEV) infection is a significant public health concern and responsible for large outbreaks of acute hepatitis in poor sanitary and living conditions. To investigate the impact of population movements on virus spreading, a large-scale population-based survey was performed in a pilgrimage- tourism area, the great Mashhad, capital city of Khorasan province. A cross-sectional study was carried out among 1582 randomly selected individuals from general population of Mashhad, north east of Iran, between May to September 2009. Serum samples were tested for total anti-HEV antibody using a specific enzyme linked immunoassay (ELISA) kit. The prevalence of HEV infection was 14.2% (225/1582) with a maximum of 25.5 % (14/55) in densely populated areas. The highest prevalence was observed in visitant areas (≥ 20%) near the holly shrine with crowded hotels and inns. The differences between these areas and other districts were statistically significant (P socio-economic status, Illiterate individuals were significantly at higher risk for infection than educated persons (P < 0.001). These findings demonstrated that, high prevalence of HEV is related to populated district, which can reach to the highest rate in hotels and inns close to visitants. Traditional sanitation and water supplying systems are the second important factor for the virus transmission. Therefore, it can be concluded that such areas need efficient surveillance systems to prevent the spreading of infectious diseases.

  7. Scattering and the Point Spread Function of the New Generation Space Telescope

    Science.gov (United States)

    Schreur, Julian J.

    1996-01-01

    Preliminary design work on the New Generation Space Telescope (NGST) is currently under way. This telescope is envisioned as a lightweight, deployable Cassegrain reflector with an aperture of 8 meters, and an effective focal length of 80 meters. It is to be folded into a small-diameter package for launch by an Atlas booster, and unfolded in orbit. The primary is to consist of an octagon with a hole at the center, and with eight segments arranged in a flower petal configuration about the octagon. The comers of the petal-shaped segments are to be trimmed so that the package will fit atop the Atlas booster. This mirror, along with its secondary will focus the light from a point source into an image which is spread from a point by diffraction effects, figure errors, and scattering of light from the surface. The distribution of light in the image of a point source is called a point spread function (PSF). The obstruction of the incident light by the secondary mirror and its support structure, the trimmed corners of the petals, and the grooves between the segments all cause the diffraction pattern characterizing an ideal point spread function to be changed, with the trimmed comers causing the rings of the Airy pattern to become broken up, and the linear grooves causing diffraction spikes running radially away from the central spot, or Airy disk. Any figure errors the mirror segments may have, or any errors in aligning the petals with the central octagon will also spread the light out from the ideal point spread function. A point spread function for a mirror the size of the NGST and having an incident wavelength of 900 nm is considered. Most of the light is confined in a circle with a diameter of 0.05 arc seconds. The ring pattern ranges in intensity from 10(exp -2) near the center to 10(exp -6) near the edge of the plotted field, and can be clearly discerned in a log plot of the intensity. The total fraction of the light scattered from this point spread function is called

  8. Abdominal Aortic Diameter Is Increased in Males with a Family History of Abdominal Aortic Aneurysms

    DEFF Research Database (Denmark)

    Mejnert Jørgensen, Trine; Houlind, K; Green, A

    2014-01-01

    and a half times increased prevalence of AAA compared with +FH with male relatives with AAA with an OR of 2.65. CONCLUSIONS: First-degree male relatives of AAA patients have wider aortas and a twofold higher prevalence of AAA compared with the age adjusted background population. The prevalence of AAA...... measurement of maximum antero-posterior aortic diameter. Family history obtained by questionnaire. Multivariate regression analysis was used to test for confounders: age, sex, smoking, comorbidity and medication. RESULTS: From the screened cohort, 569 participants had at least one first degree relative...

  9. Stress state of main stop valve with 500 mm nominal diameter white thermomechanical loading

    International Nuclear Information System (INIS)

    Koklyuev, G.A.; Plotnikov, V.P.

    1987-01-01

    The method of finite elements was applied to calculate the stress-strain state of the main isolation valve case with 500 mm nominal diameter while thermomechanical loading. Maximum stress takes place in the zone of joining nozzles with a spherical case and it attains the value of 138 MPa at working pressure of 12.5 MPa. The stress level in the point of nozzle-case welding is essentially lower than in zones of stres concentration and when excluding water hitting the slot of the lack of fusion in the route of the weld the weld service life is attained during the calculated service life

  10. Heat transfer with water in forced convection without boiling in small diameter tubes

    International Nuclear Information System (INIS)

    Ricque, Roger; Siboul, Roger

    1969-01-01

    This note presents the measurements performed for the establishment of an empirical heat transfer law for water in forced convection without boiling in small diameter tubes (2 and 4 mm), with high flow velocity and strong heat flux, and for relatively low fluid temperatures. A correlation of experimental points is obtained with a very small maximum dispersion: Nu fl = 0,0092 Re fl 0,88 Pr 0,5 (μ fl /μ p ) 0,14 . A correlation for the fiction coefficient is also presented [fr

  11. Mechanical behaviors of the dispersion nuclear fuel plates induced by fuel particle swelling and thermal effect II: Effects of variations of the fuel particle diameters

    International Nuclear Information System (INIS)

    Ding Shurong; Wang Qiming; Huo Yongzhong

    2010-01-01

    In order to predict the irradiation mechanical behaviors of plate-type dispersion nuclear fuel elements, the total burnup is divided into two stages: the initial stage and the increasing stage. At the initial stage, the thermal effects induced by the high temperature differences between the operation temperatures and the room temperature are mainly considered; and at the increasing stage, the intense mechanical interactions between the fuel particles and the matrix due to the irradiation swelling of fuel particles are focused on. The large-deformation thermo-elasto-plasticity finite element analysis is performed to evaluate the effects of particle diameters on the in-pile mechanical behaviors of fuel elements. The research results indicate that: (1) the maximum Mises stresses and equivalent plastic strains at the matrix increase with the fuel particle diameters; the effects of particle diameters on the maximum first principal stresses vary with burnup, and the considered case with the largest particle diameter holds the maximum values all along; (2) at the cladding near the interface between the fuel meat and the cladding, the Mises stresses and the first principal stresses undergo major changes with increasing burnup, and different variations exist for different particle diameter cases; (3) the maximum Mises stresses at the fuel particles rise with the particle diameters.

  12. Maximum permissible voltage of YBCO coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Wen, J.; Lin, B.; Sheng, J.; Xu, J.; Jin, Z. [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Hong, Z., E-mail: zhiyong.hong@sjtu.edu.cn [Department of Electrical Engineering, Shanghai Jiao Tong University, Shanghai (China); Wang, D.; Zhou, H.; Shen, X.; Shen, C. [Qingpu Power Supply Company, State Grid Shanghai Municipal Electric Power Company, Shanghai (China)

    2014-06-15

    Highlights: • We examine three kinds of tapes’ maximum permissible voltage. • We examine the relationship between quenching duration and maximum permissible voltage. • Continuous I{sub c} degradations under repetitive quenching where tapes reaching maximum permissible voltage. • The relationship between maximum permissible voltage and resistance, temperature. - Abstract: Superconducting fault current limiter (SFCL) could reduce short circuit currents in electrical power system. One of the most important thing in developing SFCL is to find out the maximum permissible voltage of each limiting element. The maximum permissible voltage is defined as the maximum voltage per unit length at which the YBCO coated conductors (CC) do not suffer from critical current (I{sub c}) degradation or burnout. In this research, the time of quenching process is changed and voltage is raised until the I{sub c} degradation or burnout happens. YBCO coated conductors test in the experiment are from American superconductor (AMSC) and Shanghai Jiao Tong University (SJTU). Along with the quenching duration increasing, the maximum permissible voltage of CC decreases. When quenching duration is 100 ms, the maximum permissible of SJTU CC, 12 mm AMSC CC and 4 mm AMSC CC are 0.72 V/cm, 0.52 V/cm and 1.2 V/cm respectively. Based on the results of samples, the whole length of CCs used in the design of a SFCL can be determined.

  13. Observations on placentome diameters in gestating West African ...

    African Journals Online (AJOL)

    ADEYEYE

    2015-09-09

    /10.4314/sokjvs.v13i3.4. Observations on placentome diameters in gestating West. African dwarf does experimentally infected with Trypanosoma brucei. OO Leigh. Department of Veterinary Surgery and Reproduction, ...

  14. Porosity Assessment for Different Diameters of Coir Lignocellulosic Fibers

    Science.gov (United States)

    da Luz, Fernanda Santos; Paciornik, Sidnei; Monteiro, Sergio Neves; da Silva, Luiz Carlos; Tommasini, Flávio James; Candido, Verônica Scarpini

    2017-10-01

    The application of natural lignocellulosic fibers (LCFs) in engineering composites has increased interest in their properties and structural characteristics. In particular, the inherent porosity of an LCF markedly affects its density and the adhesion to polymer matrices. For the first time, both open and closed porosities of a natural LCF, for different diameter ranges, were assessed. Fibers extracted from the mesocarp of the coconut fruit were investigated by nondestructive methods of density measurements and x-ray microtomography (microCT). It was found that, for all diameter ranges, the closed porosity is significantly higher than the open porosity. The total porosity increases with diameter to around 60% for coir fibers with more than 503 μm in diameter. The amount and characteristics of these open and closed porosities were revealed by t test and Weibull statistics as well as by microCT.

  15. Heritability of retinal vessel diameters and blood pressure

    DEFF Research Database (Denmark)

    Taarnhøj, Nina C B B; Larsen, Michael; Sander, Birgit

    2006-01-01

    PURPOSE: To assess the relative influence of genetic and environmental effects on retinal vessel diameters and blood pressure in healthy adults, as well as the possible genetic connection between these two characteristics. METHODS: In 55 monozygotic and 50 dizygotic same-sex healthy twin pairs......%-80%) for CRAE, 83% (95% CI: 73%-89%) for CRVE, and 61% (95% CI: 44%-73%) for mean arterial blood pressure (MABP). Retinal artery diameter decreased with increasing age and increasing arterial blood pressure. Mean vessel diameters in the population were 165.8 +/- 14.9 microm for CRAE, 246.2 +/- 17.7 microm...... for CRVE, and 0.67 +/- 0.05 microm for AVR. No significant influence on artery or vein diameters was found for gender, smoking, body mass index (BMI), total cholesterol, fasting blood glucose, or 2-hour oral glucose tolerance test values. CONCLUSIONS: In healthy young adults with normal blood pressure...

  16. Diameter modulation of vertically aligned single-walled carbon nanotubes.

    Science.gov (United States)

    Xiang, Rong; Einarsson, Erik; Murakami, Yoichi; Shiomi, Junichiro; Chiashi, Shohei; Tang, Zikang; Maruyama, Shigeo

    2012-08-28

    We demonstrate wide-range diameter modulation of vertically aligned single-walled carbon nanotubes (SWNTs) using a wet chemistry prepared catalyst. In order to ensure compatibility to electronic applications, the current minimum mean diameter of 2 nm for vertically aligned SWNTs is challenged. The mean diameter is decreased to about 1.4 nm by reducing Co catalyst concentrations to 1/100 or by increasing Mo catalyst concentrations by five times. We also propose a novel spectral analysis method that allows one to distinguish absorbance contributions from the upper, middle, and lower parts of a nanotube array. We use this method to quantitatively characterize the slight diameter change observed along the array height. On the basis of further investigation of the array and catalyst particles, we conclude that catalyst aggregation-rather than Ostwald ripening-dominates the growth of metal particles.

  17. Deriving muscle fiber diameter from recorded single fiber potential.

    Science.gov (United States)

    Zalewska, Ewa

    2017-12-01

    The aim of the study was to estimate muscle fiber diameters through analysis of single muscle fiber potentials (SFPs) recorded in the frontalis muscle of a healthy subject. Our previously developed analytical and graphic method to derive fiber diameter from the analysis of the negative peak duration and the amplitude of SFP, was applied to a sample of ten SFPs recorded in vivo. Muscle fiber diameters derived from the simulation method for the sample of frontalis muscle SFPs are consistent with anatomical data for this muscle. The results confirm the utility of proposed simulation method. Outlying data could be considered as the result of a contribution of other fibers to the potential recorded using an SFEMG electrode. Our graphic tool provides a rapid estimation of muscle fiber diameter. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  18. Axon diameter mapping in crossing fibers with diffusion MRI

    DEFF Research Database (Denmark)

    Zhang, Hui; Dyrby, Tim B; Alexander, Daniel C

    2011-01-01

    This paper proposes a technique for a previously unaddressed problem, namely, mapping axon diameter in crossing fiber regions, using diffusion MRI. Direct measurement of tissue microstructure of this kind using diffusion MRI offers a new class of biomarkers that give more specific information about...... tissue than measures derived from diffusion tensor imaging. Most existing techniques for axon diameter mapping assume a single axon orientation in the tissue model, which limits their application to only the most coherently oriented brain white matter, such as the corpus callosum, where the single...... model to enable axon diameter mapping in voxels with crossing fibers. We show in simulation that the technique can provide robust axon diameter estimates in a two-fiber crossing with the crossing angle as small as 45 degrees. Using ex vivo imaging data, we further demonstrate the feasibility...

  19. 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.

  20. Lateral spread of P+ ions implanted in silicon through the SiO2 mask window

    International Nuclear Information System (INIS)

    Sakurai, T.; Kawata, H.; Sato, T.; Hisatsugu, T.; Hashimoto, H.; Furuya, T.

    1979-01-01

    The lateral spread of implanted P + ions and the shape of the mask window have been observed simultaneously using the technique of staining the cleaved surface and scanning electron microscopy for the Si samples with the SiO 2 mask window with a tapered edge. The mask edge with a gradient of 45 0 or 78 0 to the Si surface and the implanted n-type region with a carrier concentration higher than 2 x 10 17 /cm 3 are observed in the same photograph. The observed maximum lateral spread when the gradient of the mask edge is 45 0 is about 1.6 times larger than that when the gradient is 78 0 . The calculated results of the lateral spread agree relatively well with the experimental data although the precise analysis based on the definite basis is necessary

  1. Revealing the Maximum Strength in Nanotwinned Copper

    DEFF Research Database (Denmark)

    Lu, L.; Chen, X.; Huang, Xiaoxu

    2009-01-01

    boundary–related processes. We investigated the maximum strength of nanotwinned copper samples with different twin thicknesses. We found that the strength increases with decreasing twin thickness, reaching a maximum at 15 nanometers, followed by a softening at smaller values that is accompanied by enhanced...

  2. Modelling maximum canopy conductance and transpiration in ...

    African Journals Online (AJOL)

    There is much current interest in predicting the maximum amount of water that can be transpired by Eucalyptus trees. It is possible that industrial waste water may be applied as irrigation water to eucalypts and it is important to predict the maximum transpiration rates of these plantations in an attempt to dispose of this ...

  3. Effect Of Low External Flow On Flame Spreading Over ETFE Insulated Wire Under Microgravity

    Science.gov (United States)

    Nishizawa, Katsuhiro; Fujita, Osamu; Ito, Kenichi; Kikuchi, Masao; Olson, Sandra L.; Kashiwagi, Takashi

    2003-01-01

    Fire safety is one of the most important issues for manned space missions. A likely cause of fires in spacecraft is wire insulation combustion in electrical system. Regarding the wire insulation combustion it important to know the effect of low external flow on the combustion because of the presence of ventilation flow in spacecraft. Although, there are many researches on flame spreading over solid material at low external flows under microgravity, research dealing with wire insulation is very limited. An example of wire insulation combustion in microgravity is the Space Shuttle experiments carried out by Greenberg et al. However, the number of experiments was very limited. Therefore, the effect of low flow velocity is still not clear. The authors have reported results on flame spreading over ETFE (ethylene - tetrafluoroetylene) insulated wire in a quiescent atmosphere in microgravity by 10 seconds drop tower. The authors also performed experiments of polyethylene insulated nichrom wire combustion in low flow velocity under microgravity. The results suggested that flame spread rate had maximum value in low flow velocity condition. Another interesting issue is the effect of dilution gas, especially CO2, which is used for fire extinguisher in ISS. There are some researches working on dilution gas effect on flame spreading over solid material in quiescent atmosphere in microgravity. However the research with low external flow is limited and, of course, the research discussing a relation of the appearance of maximum wire flammability in low flow velocity region with different dilution gas cannot be found yet. The present paper, therefore, investigates the effect of opposed flow with different dilution gas on flame spreading over ETFE insulated wire and change in the presence of the maximum flammability depending on the dilution gas type is discussed within the limit of microgravity time given by ground-based facility.

  4. The transverse diameter of the chest on routine radiographs reliably estimates gestational age and weight in premature infants.

    Science.gov (United States)

    Dietz, Kelly R; Zhang, Lei; Seidel, Frank G

    2015-08-01

    Prior to digital radiography it was possible for a radiologist to easily estimate the size of a patient on an analog film. Because variable magnification may be applied at the time of processing an image, it is now more difficult to visually estimate an infant's size on the monitor. Since gestational age and weight significantly impact the differential diagnosis of neonatal diseases and determine the expected size of kidneys or appearance of the brain by MRI or US, this information is useful to a pediatric radiologist. Although this information may be present in the electronic medical record, it is frequently not readily available to the pediatric radiologist at the time of image interpretation. To determine if there was a correlation between gestational age and weight of a premature infant with their transverse chest diameter (rib to rib) on admission chest radiographs. This retrospective study was approved by the institutional review board, which waived informed consent. The maximum transverse chest diameter outer rib to outer rib was measured on admission portable chest radiographs of 464 patients admitted to the neonatal intensive care unit (NICU) during the 2010 calendar year. Regression analysis was used to investigate the association between chest diameter and gestational age/birth weight. Quadratic term of chest diameter was used in the regression model. Chest diameter was statistically significantly associated with both gestational age (P chest diameter on digital chest radiograph with the tables and graphs in our study.

  5. Gamma ray detector for solar maximum mission (SMM) of NASA

    International Nuclear Information System (INIS)

    Brunner, W.; Brichzin, K.; Sach, E.

    1981-06-01

    For NASA's Project Solar Maximum Mission-SMM (launch 14.2.80) a Gamma Ray Detector was developed, manufactured and tested to measure solar high energetic Gamma rays and Neutron fluxes within the energy range 10-160 MeV, 4,43 MeV amd 2,23 MeV. The main components of the sensor are 7 NaI crystals 3 x 3 and a CsI crystal 30 cm diameter x 7,5 cm. The rejection of charged particles is done by two plasitc scintillators and 4 CsI-shields. From the beginning of the mission the experiment is working fully successfull. (orig.) [de

  6. Social networks and spreading of epidemics

    Science.gov (United States)

    Trimper, Steffen; Zheng, Dafang; Brandau, Marian

    2004-05-01

    Epidemiological processes are studied within a recently proposed social network model using the susceptible-infected-refractory dynamics (SIR) of an epidemic. Within the network model, a population of individuals may be characterized by H independent hierarchies or dimensions, each of which consists of groupings of individuals into layers of subgroups. Detailed numerical simulations reveals that for H > 1, the global spreading results regardless of the degree of homophily α of the individuals forming a social circle. For H = 1, a transition from a global to a local spread occurs as the population becomes decomposed into increasingly homophilous groups. Multiple dimensions in classifying individuals (nodes) thus make a society (computer network) highly susceptible to large scale outbreaks of infectious diseases (viruses). The SIR-model can be extended by the inclusion of waiting times resulting in modified distribution function of the recovered.

  7. GENERAL: Epidemic spreading on networks with vaccination

    Science.gov (United States)

    Shi, Hong-Jing; Duan, Zhi-Sheng; Chen, Guan-Rong; Li, Rong

    2009-08-01

    In this paper, a new susceptible-infected-susceptible (SIS) model on complex networks with imperfect vaccination is proposed. Two types of epidemic spreading patterns (the recovered individuals have or have not immunity) on scale-free networks are discussed. Both theoretical and numerical analyses are presented. The epidemic thresholds related to the vaccination rate, the vaccination-invalid rate and the vaccination success rate on scale-free networks are demonstrated, showing different results from the reported observations. This reveals that whether or not the epidemic can spread over a network under vaccination control is determined not only by the network structure but also by the medicine's effective duration. Moreover, for a given infective rate, the proportion of individuals to vaccinate can be calculated theoretically for the case that the recovered nodes have immunity. Finally, simulated results are presented to show how to control the disease prevalence.

  8. Epidemic spreading on weighted complex networks

    International Nuclear Information System (INIS)

    Sun, Ye; Liu, Chuang; Zhang, Chu-Xu; Zhang, Zi-Ke

    2014-01-01

    Nowadays, the emergence of online services provides various multi-relation information to support the comprehensive understanding of the epidemic spreading process. In this Letter, we consider the edge weights to represent such multi-role relations. In addition, we perform detailed analysis of two representative metrics, outbreak threshold and epidemic prevalence, on SIS and SIR models. Both theoretical and simulation results find good agreements with each other. Furthermore, experiments show that, on fully mixed networks, the weight distribution on edges would not affect the epidemic results once the average weight of whole network is fixed. This work may shed some light on the in-depth understanding of epidemic spreading on multi-relation and weighted networks.

  9. Epidemic spreading on weighted complex networks

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Ye [Institute of Information Economy, Hangzhou Normal University, Hangzhou 311121 (China); Alibaba Research Center of Complexity Science, Hangzhou Normal University, Hangzhou 311121 (China); Liu, Chuang, E-mail: liuchuang@hznu.edu.cn [Institute of Information Economy, Hangzhou Normal University, Hangzhou 311121 (China); Alibaba Research Center of Complexity Science, Hangzhou Normal University, Hangzhou 311121 (China); Zhang, Chu-Xu [Institute of Information Economy, Hangzhou Normal University, Hangzhou 311121 (China); Alibaba Research Center of Complexity Science, Hangzhou Normal University, Hangzhou 311121 (China); Zhang, Zi-Ke, E-mail: zhangzike@gmail.com [Institute of Information Economy, Hangzhou Normal University, Hangzhou 311121 (China); Alibaba Research Center of Complexity Science, Hangzhou Normal University, Hangzhou 311121 (China)

    2014-01-31

    Nowadays, the emergence of online services provides various multi-relation information to support the comprehensive understanding of the epidemic spreading process. In this Letter, we consider the edge weights to represent such multi-role relations. In addition, we perform detailed analysis of two representative metrics, outbreak threshold and epidemic prevalence, on SIS and SIR models. Both theoretical and simulation results find good agreements with each other. Furthermore, experiments show that, on fully mixed networks, the weight distribution on edges would not affect the epidemic results once the average weight of whole network is fixed. This work may shed some light on the in-depth understanding of epidemic spreading on multi-relation and weighted networks.

  10. A clustering analysis of lipoprotein diameters in the metabolic syndrome

    Directory of Open Access Journals (Sweden)

    Frazier-Wood Alexis C

    2011-12-01

    Full Text Available Abstract Background The presence of smaller low-density lipoproteins (LDL has been associated with atherosclerosis risk, and the insulin resistance (IR underlying the metabolic syndrome (MetS. In addition, some research has supported the association of very low-, low- and high-density lipoprotein (VLDL HDL particle diameters with components of the metabolic syndrome (MetS, although this has been the focus of less research. We aimed to explore the relationship of VLDL, LDL and HDL diameters to MetS and its features, and by clustering individuals by their diameters of VLDL, LDL and HDL particles, to capture information across all three fractions of lipoprotein into a unified phenotype. Methods We used nuclear magnetic resonance spectroscopy measurements on fasting plasma samples from a general population sample of 1,036 adults (mean ± SD, 48.8 ± 16.2 y of age. Using latent class analysis, the sample was grouped by the diameter of their fasting lipoproteins, and mixed effects models tested whether the distribution of MetS components varied across the groups. Results Eight discrete groups were identified. Two groups (N = 251 were enriched with individuals meeting criteria for the MetS, and were characterized by the smallest LDL/HDL diameters. One of those two groups, one was additionally distinguished by large VLDL, and had significantly higher blood pressure, fasting glucose, triglycerides, and waist circumference (WC; P Conclusions While small LDL diameters remain associated with IR and the MetS, the occurrence of these in conjunction with a shift to overall larger VLDL diameter may identify those with the highest fasting glucose, TG and WC within the MetS. If replicated, the association of this phenotype with more severe IR-features indicated that it may contribute to identifying of those most at risk for incident type II diabetes and cardiometabolic disease.

  11. 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.

  12. 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

  13. Spread of edema with brain tumors

    International Nuclear Information System (INIS)

    Hosoya, Takaaki

    1987-01-01

    Cerebral edema associated with brain tumors is visualized on CT as a hypodensity lesion involving mainly the white matter. The detailed features of its evolution were investigated in a review of CT examinations performed on 56 patients with brain tumors, with the following results. 1. The susceptibility to edema varied according to the types of fibers. Association fibers were more sensitive to edema than projection and commissural fibers. 2. The edema had a characteristic of spreading along not only the association fibers but also the projection and commissural fibers. 3. The spread of edema along the association fibers was interupted in sites of convergence of the fibers such as the external capsule and just beneath the central sulcus in the certrum semiovale. 4. In some cases with intra-axial tumors, the edema extended mainly in the projection and commissural fibers considered to be more resistant to it. For example, in cases with parietal and temporal intra-axial tumors, the posterior limb of the internal capsule was often more edematous than the external capsule. 5. The edema associated with meningioma had a characteristic of spreading mainly along the association fibers. When situated close to the corpus callosum, however, the commissural fibers were also involved. Edema extending mainly in the internal capsule, thus, was rarely observed in meningioma. 6. There was unique pattern of spread of edema in frontal tumors, which differentiated their CT pattern. Therefore, the location of the tumor could be correctly diagnosed by the pattern of the edema extension, even near the central sulcus or in the operculum region. (author)

  14. Spreading of a relativistic wave packet

    International Nuclear Information System (INIS)

    Almeida, C.; Jabs, A.

    1983-01-01

    A simple general proof that the spreading velocity of a relativistic free wave packet of the Broglie waves is limited is presented. For a wide class of packets it is confirmed that the limit is the velocity of light, and it is shown how this limit is approached when the width Δp of the wave packet in momentum space tends to infinity and the minimum width σ(t=o) in ordinary space tends to zero. (Author) [pt

  15. The Equilibrium Spreading Tension of Pulmonary Surfactant

    OpenAIRE

    Dagan, Maayan P.; Hall, Stephen B.

    2015-01-01

    Monomolecular films at an air/water interface coexist at the equilibrium spreading tension (γe) with the bulk phase from which they form. For individual phospholipids, γe is single-valued, and separates conditions at which hydrated vesicles adsorb from tensions at which overcompressed monolayers collapse. With pulmonary surfactant, isotherms show that monolayers compressed on the surface of bubbles coexist with the three-dimensional collapsed phase over a range of surface tensions. γe therefo...

  16. Physical model for membrane protrusions during spreading

    International Nuclear Information System (INIS)

    Chamaraux, F; Ali, O; Fourcade, B; Keller, S; Bruckert, F

    2008-01-01

    During cell spreading onto a substrate, the kinetics of the contact area is an observable quantity. This paper is concerned with a physical approach to modeling this process in the case of ameboid motility where the membrane detaches itself from the underlying cytoskeleton at the leading edge. The physical model we propose is based on previous reports which highlight that membrane tension regulates cell spreading. Using a phenomenological feedback loop to mimic stress-dependent biochemistry, we show that the actin polymerization rate can be coupled to the stress which builds up at the margin of the contact area between the cell and the substrate. In the limit of small variation of membrane tension, we show that the actin polymerization rate can be written in a closed form. Our analysis defines characteristic lengths which depend on elastic properties of the membrane–cytoskeleton complex, such as the membrane–cytoskeleton interaction, and on molecular parameters, the rate of actin polymerization. We discuss our model in the case of axi-symmetric and non-axi-symmetric spreading and we compute the characteristic time scales as a function of fundamental elastic constants such as the strength of membrane–cytoskeleton adherence

  17. Diffusion, spread, and migration of botulinum toxin.

    Science.gov (United States)

    Ramirez-Castaneda, Juan; Jankovic, Joseph; Comella, Cynthia; Dashtipour, Khashayar; Fernandez, Hubert H; Mari, Zoltan

    2013-11-01

    Botulinum toxin (BoNT) is an acetylcholine release inhibitor and a neuromuscular blocking agent used for the treatment of a variety of neurologic and medical conditions. The efficacy and safety of BoNT depends on accurate selection and identification of intended targets but also may be determined by other factors, including physical spread of the molecule from the injection site, passive diffusion, and migration to distal sites via axonal or hematogenous transport. The passive kinetic dispersion of the toxin away from the injection site in a gradient-dependent manner may also play a role in toxin spread. In addition to unique properties of the various BoNT products, volume and dilution may also influence local and systemic distribution of BoNT. Most of the local and remote complications of BoNT injections are thought to be due to unwanted spread or diffusion of the toxin's biologic activity into adjacent and distal muscles. Despite widespread therapeutic and cosmetic use of BoNT over more than three decades, there is a remarkable paucity of published data on the mechanisms of distribution and its effects on clinical outcomes. The primary aim of this article is to critically review the available experimental and clinical literature and place it in the practical context. © 2013 International Parkinson and Movement Disorder Society.

  18. Mechanistic movement models to understand epidemic spread.

    Science.gov (United States)

    Fofana, Abdou Moutalab; Hurford, Amy

    2017-05-05

    An overlooked aspect of disease ecology is considering how and why animals come into contact with one and other resulting in disease transmission. Mathematical models of disease spread frequently assume mass-action transmission, justified by stating that susceptible and infectious hosts mix readily, and foregoing any detailed description of host movement. Numerous recent studies have recorded, analysed and modelled animal movement. These movement models describe how animals move with respect to resources, conspecifics and previous movement directions and have been used to understand the conditions for the occurrence and the spread of infectious diseases when hosts perform a type of movement. Here, we summarize the effect of the different types of movement on the threshold conditions for disease spread. We identify gaps in the literature and suggest several promising directions for future research. The mechanistic inclusion of movement in epidemic models may be beneficial for the following two reasons. Firstly, the estimation of the transmission coefficient in an epidemic model is possible because animal movement data can be used to estimate the rate of contacts between conspecifics. Secondly, unsuccessful transmission events, where a susceptible host contacts an infectious host but does not become infected can be quantified. Following an outbreak, this enables disease ecologists to identify 'near misses' and to explore possible alternative epidemic outcomes given shifts in ecological or immunological parameters.This article is part of the themed issue 'Opening the black box: re-examining the ecology and evolution of parasite transmission'. © 2017 The Author(s).

  19. Inhibited Bacterial Adhesion and Biofilm Formation on Quaternized Chitosan-Loaded Titania Nanotubes with Various Diameters

    Directory of Open Access Journals (Sweden)

    Wen-tao Lin

    2016-03-01

    Full Text Available Titania nanotube-based local drug delivery is an attractive strategy for combating implant-associated infection. In our previous study, we demonstrated that the gentamicin-loaded nanotubes could dramatically inhibit bacterial adhesion and biofilm formation on implant surfaces. Considering the overuse of antibiotics may lead to the evolution of antibiotic-resistant bacteria, we synthesized a new quaternized chitosan derivative (hydroxypropyltrimethyl ammonium chloride chitosan, HACC with a 27% degree of substitution (DS; referred to as 27% HACC that had a strong antibacterial activity and simultaneously good biocompatibility with osteogenic cells. Titania nanotubes with various diameters (80, 120, 160, and 200 nm and 200 nm length were loaded with 2 mg of HACC using a lyophilization method and vacuum drying. Two standard strain, methicillin-resistant Staphylococcus aureus (American Type Culture Collection 43300 and Staphylococcus epidermidis (American Type Culture Collection 35984, and two clinical isolates, S. aureus 376 and S. epidermidis 389, were selected to investigate the bacterial adhesion at 6 h and biofilm formation at 24, 48, and 72 h on the HACC-loaded nanotubes (NT-H using the spread plate method, confocal laser scanning microscopy (CLSM, and scanning electron microscopy (SEM. Smooth titanium (Smooth Ti was also investigated and compared. We found that NT-H could significantly inhibit bacterial adhesion and biofilm formation on its surface compared with Smooth Ti, and the NT-H with 160 nm and 200 nm diameters had stronger antibacterial activity because of the extended HACC release time of NT-H with larger diameters. Therefore, NT-H can significantly improve the antibacterial ability of orthopedic implants and provide a promising strategy to prevent implant-associated infections.

  20. First indirect x-ray imaging tests with an 88-mm diameter single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Lumpkin, A. H. [Fermilab; Macrander, A. T. [Argonne

    2017-02-01

    Using the 1-BM-C beamline at the Advanced Photon Source (APS), we have performed the initial indirect x - ray imaging point-spread-function (PSF) test of a unique 88-mm diameter YAG:Ce single crystal of only 100 - micron thickness. The crystal was bonded to a fiber optic plat e (FOP) for mechanical support and to allow the option for FO coupling to a large format camera. This configuration resolution was compared to that of self - supported 25-mm diameter crystals, with and without an Al reflective coating. An upstream monochromator was used to select 17-keV x-rays from the broadband APS bending magnet source of synchrotron radiation. The upstream , adjustable Mo collimators were then used to provide a series of x-ray source transverse sizes from 200 microns down to about 15-20 microns (FWHM) at the crystal surface. The emitted scintillator radiation was in this case lens coupled to the ANDOR Neo sCMOS camera, and the indirect x-ray images were processed offline by a MATLAB - based image processing program. Based on single Gaussian peak fits to the x-ray image projected profiles, we observed a 10.5 micron PSF. This sample thus exhibited superior spatial resolution to standard P43 polycrystalline phosphors of the same thickness which would have about a 100-micron PSF. Lastly, this single crystal resolution combined with the 88-mm diameter makes it a candidate to support future x-ray diffraction or wafer topography experiments.

  1. A nuclear-medical method applied for determining the choledochus diameter after cholecystectomy

    International Nuclear Information System (INIS)

    Wolf, M.

    1980-01-01

    54 patients (46 of them females, 8 males) who underwent cholecystectomy at least 4 years ago, were followed up roentgenologically by infusion cholangiography and nuclear-medicinally by quantitative hepatobiliary functional scintiscanning (HBFS). The ROI method applied for HBFS permits to record time/activity curves above the liver parenchyma (A) and the porta of the liver (B). By substracting curve A of curve B with the scale in which A is incorporated in B, a curve B' results, indicating the flow volume through the porta of the liver. The quotient Q=maximum pulse A to B/maximum pulse B to B indicates the portion of the liver parenchyma in the porta curve. The quotient represents a measure for the total volume of the large bile ducts included in the region of the porta of the liver. The quantity 1-Q/Q was put in relation with the roentgenologically determined common bile duct diameters. It resulted that both quantities correlated well, with a correlation coefficient of r=-0.860. Thus, the choledochus diameter can be determined in a primarily functional examination with a precision of 2 mm, a degree which permits the detection of clinically relevant discharge malfunctions. It was not possible to detect peristalsis-dependent phenomena with a dosage of 4-5 mCi 99 mTc-diethyl-IDA, an irradiation dose which was sufficient for answering the clinical questions and could be justified for the patients. (orig.) [de

  2. 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)

  3. Parametric Probability Distribution Functions for Axon Diameters of Corpus Callosum

    Directory of Open Access Journals (Sweden)

    Farshid eSepehrband

    2016-05-01

    Full Text Available Axon diameter is an important neuroanatomical characteristic of the nervous system that alters in the course of neurological disorders such as multiple sclerosis. Axon diameters vary, even within a fiber bundle, and are not normally distributed. An accurate distribution function is therefore beneficial, either to describe axon diameters that are obtained from a direct measurement technique (e.g., microscopy, or to infer them indirectly (e.g., using diffusion-weighted MRI. The gamma distribution is a common choice for this purpose (particularly for the inferential approach because it resembles the distribution profile of measured axon diameters which has been consistently shown to be non-negative and right-skewed. In this study we compared a wide range of parametric probability distribution functions against empirical data obtained from electron microscopy images. We observed that the gamma distribution fails to accurately describe the main characteristics of the axon diameter distribution, such as location and scale of the mode and the profile of distribution tails. We also found that the generalized extreme value distribution consistently fitted the measured distribution better than other distribution functions. This suggests that there may be distinct subpopulations of axons in the corpus callosum, each with their own distribution profiles. In addition, we observed that several other distributions outperformed the gamma distribution, yet had the same number of unknown parameters; these were the inverse Gaussian, log normal, log logistic and Birnbaum-Saunders distributions.

  4. Fast and accurate detection of spread source in large complex networks.

    Science.gov (United States)

    Paluch, Robert; Lu, Xiaoyan; Suchecki, Krzysztof; Szymański, Bolesław K; Hołyst, Janusz A

    2018-02-06

    Spread over complex networks is a ubiquitous process with increasingly wide applications. Locating spread sources is often important, e.g. finding the patient one in epidemics, or source of rumor spreading in social network. Pinto, Thiran and Vetterli introduced an algorithm (PTVA) to solve the important case of this problem in which a limited set of nodes act as observers and report times at which the spread reached them. PTVA uses all observers to find a solution. Here we propose a new approach in which observers with low quality information (i.e. with large spread encounter times) are ignored and potential sources are selected based on the likelihood gradient from high quality observers. The original complexity of PTVA is O(N α ), where α ∈ (3,4) depends on the network topology and number of observers (N denotes the number of nodes in the network). Our Gradient Maximum Likelihood Algorithm (GMLA) reduces this complexity to O (N 2 log (N)). Extensive numerical tests performed on synthetic networks and real Gnutella network with limitation that id's of spreaders are unknown to observers demonstrate that for scale-free networks with such limitation GMLA yields higher quality localization results than PTVA does.

  5. Energy spread of different electron beams. Part I: thermoionic electron beams

    International Nuclear Information System (INIS)

    Troyon, M.; Zinzindohoue, P.

    1987-01-01

    Energy spread ΔE and brightness B are the two important parameters for defining electron beam quality. An attempt in this paper for three types of generally used thermionic cathodes (hairpin, pointed and LaB6) and three particular Wehnelt shapes (re-entrant, flat and conical) has been made. It has been demonstrated that the energy spread is much more dependent on brightness than on total emitted current; for a given brightness the best gun is the one that gives smaller total emitted current. One can expect with pointed and LaB6 filaments when compared with hairpin filament at a given constant energy spread, the brightness increases by about 2 to 3 times. Higher brightness is obtained simultaneously with larger energy spread: for example, at 20 kV, the maximum brightness and corresponding energy spread of a pointed and a hairpin filament mounted in a flat Wehnelt are B = 4x10 5 Acm -2 sr -1 , ΔE = 3.3 eV and B = 6 x 10 4 Acm -2 sr -1 , ΔE = 2 eV respectively

  6. A passerine spreads its tail to facilitate a rapid recovery of its body posture during hovering.

    Science.gov (United States)

    Su, Jian-Yuan; Ting, Shang-Chieh; Chang, Yu-Hung; Yang, Jing-Tang

    2012-07-07

    We demonstrate experimentally that a passerine exploits tail spreading to intercept the downward flow induced by its wings to facilitate the recovery of its posture. The periodic spreading of its tail by the White-eye bird exhibits a phase correlation with both wingstroke motion and body oscillation during hovering flight. During a downstroke, a White-eye's body undergoes a remarkable pitch-down motion, with the tail undergoing an upward swing. This pitch-down motion becomes appropriately suppressed at the end of the downstroke; the bird's body posture then recovers gradually to its original status. Employing digital particle-image velocimetry, we show that the strong downward flow induced by downstroking the wings serves as an external jet flow impinging upon the tail, providing a depressing force on the tail to counteract the pitch-down motion of the bird's body. Spreading of the tail enhances a rapid recovery of the body posture because increased forces are experienced. The maximum force experienced by a spread tail is approximately 2.6 times that of a non-spread tail.

  7. MXLKID: a maximum likelihood parameter identifier

    International Nuclear Information System (INIS)

    Gavel, D.T.

    1980-07-01

    MXLKID (MaXimum LiKelihood IDentifier) is a computer program designed to identify unknown parameters in a nonlinear dynamic system. Using noisy measurement data from the system, the maximum likelihood identifier computes a likelihood function (LF). Identification of system parameters is accomplished by maximizing the LF with respect to the parameters. The main body of this report briefly summarizes the maximum likelihood technique and gives instructions and examples for running the MXLKID program. MXLKID is implemented LRLTRAN on the CDC7600 computer at LLNL. A detailed mathematical description of the algorithm is given in the appendices. 24 figures, 6 tables

  8. Estimation of maximum credible atmospheric radioactivity concentrations and dose rates from nuclear tests

    International Nuclear Information System (INIS)

    Telegadas, K.

    1979-01-01

    A simple technique is presented for estimating maximum credible gross beta air concentrations from nuclear detonations in the atmosphere, based on aircraft sampling of radioactivity following each Chinese nuclear test from 1964 to 1976. The calculated concentration is a function of the total yield and fission yield, initial vertical radioactivity distribution, time after detonation, and rate of horizontal spread of the debris with time. calculated maximum credible concentrations are compared with the highest concentrations measured during aircraft sampling. The technique provides a reasonable estimate of maximum air concentrations from 1 to 10 days after a detonation. An estimate of the whole-body external gamma dose rate corresponding to the maximum credible gross beta concentration is also given. (author)

  9. Researches on thermal and rheological properties of cream- and vegetable spread

    Directory of Open Access Journals (Sweden)

    A. N. Ostrikov

    2016-01-01

    Full Text Available Researches of thermal and rheological properties of cream- and vegetable spread are necessary for the scientific substantiation of their obtaining process, namely mixing and crystallization processes. As the object of research, we chose a cream- and vegetable spread, with the following composition: peanut butter 10%; wheat germ oil 10%; linseed oil 20%; butter 59.8%; emulsifier 0.2%. With the data obtained in the course of research of the rheological properties of cream- and vegetable spread, one can subsequently generate recommendations for optimization of technological modes of production. In particular, one can solve problems of intensification of hydro-mechanical and thermal processes by carrying them out at such a temperature and speed when the maximum preservation of the produced product structure will be achieved. Determination of thermal characteristics was carried out in the apparatus for the study of thermal and rheological properties of viscoelastic liquids Coesfeld RT-1394H. Rheological researches of cream- and vegetable spread were carried out on a series of viscometers SV-10 and PB-8m. The graphs of spread dynamic viscosity dependence on the temperature, and the dependence of the effective viscosity of the spread and vegetable oils on the shear rate were built according to experimental data. The data obtained is rational to choose the equipment for processing and production of cream- and vegetable spread, to simulate processes taking place in the production process, to solve problems of intensification of thermal and hydro-mechanical processes reasonably, by conducting the production process at temperatures that do not cause the destruction of the product structure.

  10. Measurement of nanoscale molten polymer droplet spreading using atomic force microscopy

    Science.gov (United States)

    Soleymaniha, Mohammadreza; Felts, Jonathan R.

    2018-03-01

    We present a technique for measuring molten polymer spreading dynamics with nanometer scale spatial resolution at elevated temperatures using atomic force microscopy (AFM). The experimental setup is used to measure the spreading dynamics of polystyrene droplets with 2 μm diameters at 115-175 °C on sapphire, silicon oxide, and mica. Custom image processing algorithms determine the droplet height, radius, volume, and contact angle of each AFM image over time to calculate the droplet spreading dynamics. The contact angle evolution follows a power law with time with experimentally determined values of -0.29 ± 0.01, -0.08 ± 0.02, and -0.21 ± 0.01 for sapphire, silicon oxide, and mica, respectively. The non-zero steady state contact angles result in a slower evolution of contact angle with time consistent with theories combining molecular kinetic and hydrodynamic models. Monitoring the cantilever phase provides additional information about the local mechanics of the droplet surface. We observe local crystallinity on the molten droplet surface, where crystalline structures appear to nucleate at the contact line and migrate toward the top of the droplet. Increasing the temperature from 115 °C to 175 °C reduced surface crystallinity from 35% to 12%, consistent with increasingly energetically favorable amorphous phase as the temperature approaches the melting temperature. This platform provides a way to measure spreading dynamics of extremely small volumes of heterogeneously complex fluids not possible through other means.

  11. The effect of induction motor shaft diameter on motor performance

    Directory of Open Access Journals (Sweden)

    Asım Gökhan Yetgin

    2017-10-01

    Full Text Available Induction motors are used in many areas from the past to the present and in different fields with the development of technology has continued to be used. It is obvious that induction motors as an improvement to the efficiency in terms of energy saving would cause great benefit. In that context, induction motor manufacturers and designers are constantly trying out new methods to improve motor performance and efficiency. In this study, what would be the optimum diameter of the shaft in order to increase the efficiency of the induction motor were investigated. In the study, 5.5 kW, 7.5 kW and 11 kW motors analyzes were also performed. Obtained shaft diameter values were compared with the manufacturer values. In addition, critical points such as the magnetic flux values, weight values and performances of the motors were examined and optimal shaft diameter values for each motor have been determined.

  12. NEOWISE REACTIVATION MISSION YEAR TWO: ASTEROID DIAMETERS AND ALBEDOS

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, C. R.; Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mainzer, A.; Bauer, J.; Kramer, E. A.; Masiero, J.; Sonnett, S. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Wright, E. L., E-mail: cnugent@ipac.caltech.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2016-09-01

    The Near-Earth Object Wide-Field Infrared Survey Explorer (NEOWISE) mission continues to detect, track, and characterize minor planets. We present diameters and albedos calculated from observations taken during the second year since the spacecraft was reactivated in late 2013. These include 207 near-Earth asteroids (NEAs) and 8885 other asteroids. Of the NEAs, 84% NEAs did not have previously measured diameters and albedos by the NEOWISE mission. Comparison of sizes and albedos calculated from NEOWISE measurements with those measured by occultations, spacecraft, and radar-derived shapes shows accuracy consistent with previous NEOWISE publications. Diameters and albedos fall within ±∼20% and ±∼40%, 1-sigma, respectively, of those measured by these alternate techniques. NEOWISE continues to preferentially discover near-Earth objects which are large (>100 m), and have low albedos.

  13. Divergent biparietal diameter growth rates in twin pregnancies.

    Science.gov (United States)

    Houlton, M C

    1977-05-01

    Twenty-eight twin pregnancies were monitored by serial ultrasonic cephalometry from 30 or 31 weeks' gestation. The rates of growth of the individual twins as determined by biparietal diameters were similar in 11 cases (39%) and divergent in 17 (61%). When the rates of growth were divergent, the lesser rate was always below the mean for singleton pregnancies, and the incidence of small-for-gestational-age babies was 18 of 34 (53%). It was apparent that the greater the difference in biparietal diameters within the 2 weeks preceding delivery, the higher the risk of a small-for-gestation-age baby being delivered. No comment could be made on the growth rate prior to 28 weeks except that at diagnosis there was little or no difference in biparietal diameters.

  14. Bubble behaviour and mean diameter in subcooled flow boiling

    Energy Technology Data Exchange (ETDEWEB)

    Zeitoun, O.; Shoukri, M. [McMaster Univ., Hamilton, Ontario (Canada)

    1995-09-01

    Bubble behaviour and mean bubble diameter in subcooled upward flow boiling in a vertical annular channel were investigated under low pressure and mass flux conditions. A high speed video system was used to visualize the subcooled flow boiling phenomenon. The high speed photographic results indicated that, contrary to the common understanding, bubbles tend to detach from the heating surface upstream of the net vapour generation point. Digital image processing technique was used to measure the mean bubble diameter along the subcooled flow boiling region. Data on the axial area-averaged void fraction distributions were also obtained using a single beam gamma densitometer. Effects of the liquid subcooling, applied heat flux and mass flux on the mean bubble size were investigated. A correlation for the mean bubble diameter as a function of the local subcooling, heat flux and mass flux was obtained.

  15. 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\\.

  16. Measurements of the diameter of the supernova SN 1987A

    International Nuclear Information System (INIS)

    Karovska, M.; Nisenson, P.; Standley, C.; Heathcote, S.R.

    1991-01-01

    Speckle interferometric measurements of the angular diameter of SN 1987A in the Large Magellanic Cloud, obtained at 664 days after the outburst are presented. Diameters were estimated with milliarcsec precision at 657 nm and 550 nm by fitting model visibility functions to the data corresponding to different intensity distributions for the supernova disk. Measurements made assuming a uniform intensity distribution were compared to the uniform disk measurements obtained from 30 days after the explosion. Diameter measurements obtained near the center of the H-alpha line are consistent with homologous expansion of the supernova shell with a mean velocity of 2850 km/s. The linear least-squares fit to the measurements obtained at other wavelengths from 260 days after the explosion yielded a somewhat lower mean expansion velocity. 8 refs

  17. Diameter sensitive effect in singlewalled carbon nanotubes upon acid treatment

    International Nuclear Information System (INIS)

    Costa, S.; Borowiak-Palen, E.

    2009-01-01

    Singlewalled carbon nanotubes (SWCNT) exhibit very unique properties. As an electronic system they undergo amphoteric doping effects (n-type and p-type) which can be reversed. These processes affect the optical and vibronic properties of the carbon nanotubes. The most common and widely used procedure which changes the properties of the SWCNT is acid treatment applied as a purification procedure. This effect has been widely studied but not fully understood so far. Here, we present a study, in which a diameter sensitive effect has been observed. Therefore, two kinds of SWCNT samples have been studied: (i) produced via chemical vapour deposition with a broad diameter distribution, and (ii) synthesised by the laser ablation technique which is commonly known to result in narrow diameter distribution bulk SWCNT samples. Resonance Raman spectroscopy, optical absorption spectroscopy, and Fourier transform middle-infrared spectroscopy have been applied for the characterisation of the samples.

  18. Characteristics of two-phase flows in large diameter channels

    Energy Technology Data Exchange (ETDEWEB)

    Schlegel, J.P., E-mail: schlegelj@mst.edu [Department of Mining and Nuclear Engineering, Missouri University of Science and Technology, 301 W 14th St., Rolla, MO 65401 (United States); Hibiki, T.; Ishii, M. [School of Nuclear Engineering, Purdue University, 400 Central Dr., West Lafayette, IN 47907 (United States)

    2016-12-15

    Two-phase flows in large diameter channels have a great deal of importance in a wide variety of industrial applications. Nuclear systems, petroleum refineries, and chemical processes make extensive use of larger systems. Flows in such channels have very different properties from flows in smaller channels which are typically used in experimental research. In this paper, the various differences between flows in large and small channels are highlighted using the results of previous experimental and analytical research. This review is followed by a review of recent experiments in and model development for flows in large diameter channels performed by the authors. The topics of these research efforts range from void fraction and interfacial area concentration measurement to flow regime identification and modeling, drift-flux modeling for high void fraction conditions, and evaluation of interfacial area transport models for large diameter channels.

  19. Dominance of layer-specific microvessel dilation in contrast-enhanced high-resolution fMRI: Comparison between hemodynamic spread and vascular architecture with CLARITY.

    Science.gov (United States)

    Poplawsky, Alexander John; Fukuda, Mitsuhiro; Kang, Bok-Man; Kim, Jae Hwan; Suh, Minah; Kim, Seong-Gi

    2017-08-16

    Contrast-enhanced cerebral blood volume-weighted (CBVw) fMRI response peaks are specific to the layer of evoked synaptic activity (Poplawsky et al., 2015), but the spatial resolution limit of CBVw fMRI is unknown. In this study, we measured the laminar spread of the CBVw fMRI evoked response in the external plexiform layer (EPL, 265 ± 65 μm anatomical thickness, mean ± SD, n = 30 locations from 5 rats) of the rat olfactory bulb during electrical stimulation of the lateral olfactory tract and examined its potential vascular source. First, we obtained the evoked CBVw fMRI responses with a 55 × 55 μm 2 in-plane resolution and a 500-μm thickness at 9.4 T, and found that the fMRI signal peaked predominantly in the inner half of EPL (136 ± 54 μm anatomical thickness). The mean full-width at half-maximum of these fMRI peaks was 347 ± 102 μm and the functional spread was approximately 100 or 200 μm when the effects of the laminar thicknesses of EPL or inner EPL were removed, respectively. Second, we visualized the vascular architecture of EPL from a different rat using a Clear Lipid-exchanged Anatomically Rigid Imaging/immunostaining-compatible Tissue hYdrogel (CLARITY)-based tissue preparation method and confocal microscopy. Microvascular segments with an outer diameter of limit of the fMRI spatial resolution is approximately the average length of 1-2 microvessel segments, which may be sufficient for examining sublaminar circuits. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. 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

  1. The edge artifact in the point-spread function-based PET reconstruction at different sphere-to-background ratios of radioactivity.

    Science.gov (United States)

    Kidera, Daisuke; Kihara, Ken; Akamatsu, Go; Mikasa, Shohei; Taniguchi, Takafumi; Tsutsui, Yuji; Takeshita, Toshiki; Maebatake, Akira; Miwa, Kenta; Sasaki, Masayuki

    2016-02-01

    The aim of this study was to quantitatively evaluate the edge artifacts in PET images reconstructed using the point-spread function (PSF) algorithm at different sphere-to-background ratios of radioactivity (SBRs). We used a NEMA IEC body phantom consisting of six spheres with 37, 28, 22, 17, 13 and 10 mm in inner diameter. The background was filled with (18)F solution with a radioactivity concentration of 2.65 kBq/mL. We prepared three sets of phantoms with SBRs of 16, 8, 4 and 2. The PET data were acquired for 20 min using a Biograph mCT scanner. The images were reconstructed with the baseline ordered subsets expectation maximization (OSEM) algorithm, and with the OSEM + PSF correction model (PSF). For the image reconstruction, the number of iterations ranged from one to 10. The phantom PET image analyses were performed by a visual assessment of the PET images and profiles, a contrast recovery coefficient (CRC), which is the ratio of SBR in the images to the true SBR, and the percent change in the maximum count between the OSEM and PSF images (Δ % counts). In the PSF images, the spheres with a diameter of 17 mm or larger were surrounded by a dense edge in comparison with the OSEM images. In the spheres with a diameter of 22 mm or smaller, an overshoot appeared in the center of the spheres as a sharp peak in the PSF images in low SBR. These edge artifacts were clearly observed in relation to the increase of the SBR. The overestimation of the CRC was observed in 13 mm spheres in the PSF images. In the spheres with a diameter of 17 mm or smaller, the Δ % counts increased with an increasing SBR. The Δ % counts increased to 91 % in the 10-mm sphere at the SBR of 16. The edge artifacts in the PET images reconstructed using the PSF algorithm increased with an increasing SBR. In the small spheres, the edge artifact was observed as a sharp peak at the center of spheres and could result in overestimation.

  2. Maximum neutron flux in thermal reactors

    International Nuclear Information System (INIS)

    Strugar, P.V.

    1968-12-01

    Direct approach to the problem is to calculate spatial distribution of fuel concentration if the reactor core directly using the condition of maximum neutron flux and comply with thermal limitations. This paper proved that the problem can be solved by applying the variational calculus, i.e. by using the maximum principle of Pontryagin. Mathematical model of reactor core is based on the two-group neutron diffusion theory with some simplifications which make it appropriate from maximum principle point of view. Here applied theory of maximum principle are suitable for application. The solution of optimum distribution of fuel concentration in the reactor core is obtained in explicit analytical form. The reactor critical dimensions are roots of a system of nonlinear equations and verification of optimum conditions can be done only for specific examples

  3. Maximum allowable load on wheeled mobile manipulators

    International Nuclear Information System (INIS)

    Habibnejad Korayem, M.; Ghariblu, H.

    2003-01-01

    This paper develops a computational technique for finding the maximum allowable load of mobile manipulator during a given trajectory. The maximum allowable loads which can be achieved by a mobile manipulator during a given trajectory are limited by the number of factors; probably the dynamic properties of mobile base and mounted manipulator, their actuator limitations and additional constraints applied to resolving the redundancy are the most important factors. To resolve extra D.O.F introduced by the base mobility, additional constraint functions are proposed directly in the task space of mobile manipulator. Finally, in two numerical examples involving a two-link planar manipulator mounted on a differentially driven mobile base, application of the method to determining maximum allowable load is verified. The simulation results demonstrates the maximum allowable load on a desired trajectory has not a unique value and directly depends on the additional constraint functions which applies to resolve the motion redundancy

  4. Maximum phytoplankton concentrations in the sea

    DEFF Research Database (Denmark)

    Jackson, G.A.; Kiørboe, Thomas

    2008-01-01

    A simplification of plankton dynamics using coagulation theory provides predictions of the maximum algal concentration sustainable in aquatic systems. These predictions have previously been tested successfully against results from iron fertilization experiments. We extend the test to data collect...

  5. Residual stresses and critical diameter in vitreous matrix materials

    International Nuclear Information System (INIS)

    Mastelaro, Valmor R.; Zanotto, Edgar D.

    1995-01-01

    The present study was undertaken to test the validity of existing models for: i) the residual internal stresses which arise due to thermal and elastic mismatch in duplex systems, and ii) the critical particle diameter for spontaneous cracking. Partially crystallized 1,07 Na 2 O-2 Ca O-3 Si O 2 - 6% P 2 O 5 glasses were studied. The experimental residual stress was in excellent agreement with the calculated value, however, the critical particle diameter, estimated by an energy balance approach, was more than ten times smaller than the experimental value. This discrepancy indicates that the energy model is not applicable in this case. (author)

  6. NEOWISE REACTIVATION MISSION YEAR ONE: PRELIMINARY ASTEROID DIAMETERS AND ALBEDOS

    Energy Technology Data Exchange (ETDEWEB)

    Nugent, C. R.; Cutri, R. M. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Mainzer, A.; Masiero, J.; Bauer, J.; Kramer, E.; Sonnett, S.; Stevenson, R. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Grav, T. [Planetary Science Institute, Tucson, AZ (United States); Wright, E. L., E-mail: cnugent@ipac.caltech.edu [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States)

    2015-12-01

    We present preliminary diameters and albedos for 7956 asteroids detected in the first year of the NEOWISE Reactivation mission. Of those, 201 are near-Earth asteroids and 7755 are Main Belt or Mars-crossing asteroids. 17% of these objects have not been previously characterized using the Near-Earth Object Wide-field Infrared Survey Explorer, or “NEOWISE” thermal measurements. Diameters are determined to an accuracy of ∼20% or better. If good-quality H magnitudes are available, albedos can be determined to within ∼40% or better.

  7. Fitting diameter distribution models to data from forest inventories with concentric plot design

    Energy Technology Data Exchange (ETDEWEB)

    Nanos, N.; Sjöstedt de Luna, S.

    2017-11-01

    Aim: Several national forest inventories use a complex plot design based on multiple concentric subplots where smaller diameter trees are inventoried when lying in the smaller-radius subplots and ignored otherwise. Data from these plots are truncated with threshold (truncation) diameters varying according to the distance from the plot centre. In this paper we designed a maximum likelihood method to fit the Weibull diameter distribution to data from concentric plots. Material and methods: Our method (M1) was based on multiple truncated probability density functions to build the likelihood. In addition, we used an alternative method (M2) presented recently. We used methods M1 and M2 as well as two other reference methods to estimate the Weibull parameters in 40000 simulated plots. The spatial tree pattern of the simulated plots was generated using four models of spatial point patterns. Two error indices were used to assess the relative performance of M1 and M2 in estimating relevant stand-level variables. In addition, we estimated the Quadratic Mean plot Diameter (QMD) using Expansion Factors (EFs). Main results: Methods M1 and M2 produced comparable estimation errors in random and cluster tree spatial patterns. Method M2 produced biased parameter estimates in plots with inhomogeneous Poisson patterns. Estimation of QMD using EFs produced biased results in plots within inhomogeneous intensity Poisson patterns. Research highlights:We designed a new method to fit the Weibull distribution to forest inventory data from concentric plots that achieves high accuracy and precision in parameter estimates regardless of the within-plot spatial tree pattern.

  8. The cost of simplifying air travel when modeling disease spread.

    Directory of Open Access Journals (Sweden)

    Justin Lessler

    Full Text Available BACKGROUND: Air travel plays a key role in the spread of many pathogens. Modeling the long distance spread of infectious disease in these cases requires an air travel model. Highly detailed air transportation models can be over determined and computationally problematic. We compared the predictions of a simplified air transport model with those of a model of all routes and assessed the impact of differences on models of infectious disease. METHODOLOGY/PRINCIPAL FINDINGS: Using U.S. ticket data from 2007, we compared a simplified "pipe" model, in which individuals flow in and out of the air transport system based on the number of arrivals and departures from a given airport, to a fully saturated model where all routes are modeled individually. We also compared the pipe model to a "gravity" model where the probability of travel is scaled by physical distance; the gravity model did not differ significantly from the pipe model. The pipe model roughly approximated actual air travel, but tended to overestimate the number of trips between small airports and underestimate travel between major east and west coast airports. For most routes, the maximum number of false (or missed introductions of disease is small (<1 per day but for a few routes this rate is greatly underestimated by the pipe model. CONCLUSIONS/SIGNIFICANCE: If our interest is in large scale regional and national effects of disease, the simplified pipe model may be adequate. If we are interested in specific effects of interventions on particular air routes or the time for the disease to reach a particular location, a more complex point-to-point model will be more accurate. For many problems a hybrid model that independently models some frequently traveled routes may be the best choice. Regardless of the model used, the effect of simplifications and sensitivity to errors in parameter estimation should be analyzed.

  9. Strain analysis of different diameter Morse taper implants under overloading compressive conditions

    Directory of Open Access Journals (Sweden)

    Carolina Guimarães CASTRO

    2015-01-01

    Full Text Available The aim of this study was to evaluate the amount of deformation from compression caused by different diameters of Morse taper implants and the residual deformation after load removal. Thirty Morse taper implants lacking external threads were divided into 3 groups (n = 10 according to their diameter as follows: 3.5 mm, 4.0 mm and 5.0 mm. Two-piece abutments were fixed into the implants, and the samples were subjected to compressive axial loading up to 1500 N of force. During the test, one strain gauge remained fixed to the cervical portion of each implant to measure the strain variation. The strain values were recorded at two different time points: at the maximum load (1500 N and 60 seconds after load removal. To calculate the strain at the implant/abutment interface, a mathematical formula was applied. Data were analyzed using a one-way Anova and Tukey’s test (α = 0.05. The 5.0 mm diameter implant showed a significantly lower strain (650.5 μS ± 170.0 than the 4.0 mm group (1170.2 μS ± 374.7 and the 3.5 mm group (1388.1 μS ± 326.6 (p < 0.001, regardless of the load presence. The strain values decreased by approximately 50% after removal of the load, regardless of the implant diameter. The 5.0 mm implant showed a significantly lower strain at the implant/abutment interface (943.4 μS ± 504.5 than the 4.0 mm group (1057.4 μS ± 681.3 and the 3.5 mm group (1159.6 μS ± 425.9 (p < 0.001. According to the results of this study, the diameter influenced the strain around the internal and external walls of the cervical region of Morse taper implants; all diameters demonstrated clinically acceptable values of strain.

  10. Maximum-Likelihood Detection Of Noncoherent CPM

    Science.gov (United States)

    Divsalar, Dariush; Simon, Marvin K.

    1993-01-01

    Simplified detectors proposed for use in maximum-likelihood-sequence detection of symbols in alphabet of size M transmitted by uncoded, full-response continuous phase modulation over radio channel with additive white Gaussian noise. Structures of receivers derived from particular interpretation of maximum-likelihood metrics. Receivers include front ends, structures of which depends only on M, analogous to those in receivers of coherent CPM. Parts of receivers following front ends have structures, complexity of which would depend on N.

  11. Influence of shoulder diameter on Temperature and Z-parameter during friction stir welding of Al 6082 alloy

    Science.gov (United States)

    Kishore Mugada, Krishna; Adepu, Kumar

    2018-03-01

    In this research article, the effect of increasing shoulder diameter on temperature and Zener Holloman (Z)-parameter for friction stir butt welded AA6082-T6 was studied. The temperature at the Advancing side (AS) of weld was measured using the K-Type thermocouple at four different equidistant locations. The developed analytical model is utilized to predict the maximum temperature (Tpeak) during the welding. The strain, strain rate, Z- Parameter for all the shoulders at four distinct locations were evaluated. The temperature increases with increase in shoulder diameter and the maximum temperature was recorded for 24mm shoulder diameter. The computed log Z values are compared with the available process map and results shows that the values are in stable flow region and near to stir zone the values are in Dynamic recrystallization region (DRX). The axial load (Fz) and total tool torque (N-m) are found to be higher for shoulder diameter of 21 mm i.e., 6.3 kN and 56.5 N-m respectively.

  12. Default Spread dan Term Spread sebagai Variabel Proxy Siklus Bisnis pada Model Fama-French

    Directory of Open Access Journals (Sweden)

    Edwin Hendra

    2015-08-01

    Full Text Available This research aims to apply the Fama-French models and test the effect of alternative variable of bond yield spread, default spread (RBBB – RAAA and RAAA – RF, and the term spread (RSUN10-RSUN1, as proxy variables of the business cycle, in IDX stock data during 2005-2010. Four types of asset pricing models tested are Sharpe-Lintner CAPM, Fama-French models, Hwang et al.model, and hybrid model. The results showed that the size effect and value effect has an impact on excess stock returns. Slopes of market beta, SMB, and HML are more sensitive to stock big size and high B / M. Default spreads and term spreads in Hwang et al. model can explain the value effect, and weakly explain the size effect, meanwhile the power of explanation disappeared on Hybrid models. Based on the assessment adjusted R2 and the frequency of rejection of non-zero alpha, is found that the hybrid model is the most suitable model.  

  13. Spreading in online social networks: the role of social reinforcement.

    Science.gov (United States)

    Zheng, Muhua; Lü, Linyuan; Zhao, Ming

    2013-07-01

    Some epidemic spreading models are usually applied to analyze the propagation of opinions or news. However, the dynamics of epidemic spreading and information or behavior spreading are essentially different in many aspects. Centola's experiments [Science 329, 1194 (2010)] on behavior spreading in online social networks showed that the spreading is faster and broader in regular networks than in random networks. This result contradicts with the former understanding that random networks are preferable for spreading than regular networks. To describe the spreading in online social networks, a unknown-known-approved-exhausted four-status model was proposed, which emphasizes the effect of social reinforcement and assumes that the redundant signals can improve the probability of approval (i.e., the spreading rate). Performing the model on regular and random networks, it is found that our model can well explain the results of Centola's experiments on behavior spreading and some former studies on information spreading in different parameter space. The effects of average degree and network size on behavior spreading process are further analyzed. The results again show the importance of social reinforcement and are accordant with Centola's anticipation that increasing the network size or decreasing the average degree will enlarge the difference of the density of final approved nodes between regular and random networks. Our work complements the former studies on spreading dynamics, especially the spreading in online social networks where the information usually requires individuals' confirmations before being transmitted to others.

  14. Predictive validation of an influenza spread model.

    Directory of Open Access Journals (Sweden)

    Ayaz Hyder

    Full Text Available BACKGROUND: Modeling plays a critical role in mitigating impacts of seasonal influenza epidemics. Complex simulation models are currently at the forefront of evaluating optimal mitigation strategies at multiple scales and levels of organization. Given their evaluative role, these models remain limited in their ability to predict and forecast future epidemics leading some researchers and public-health practitioners to question their usefulness. The objective of this study is to evaluate the predictive ability of an existing complex simulation model of influenza spread. METHODS AND FINDINGS: We used extensive data on past epidemics to demonstrate the process of predictive validation. This involved generalizing an individual-based model for influenza spread and fitting it to laboratory-confirmed influenza infection data from a single observed epidemic (1998-1999. Next, we used the fitted model and modified two of its parameters based on data on real-world perturbations (vaccination coverage by age group and strain type. Simulating epidemics under these changes allowed us to estimate the deviation/error between the expected epidemic curve under perturbation and observed epidemics taking place from 1999 to 2006. Our model was able to forecast absolute intensity and epidemic peak week several weeks earlier with reasonable reliability and depended on the method of forecasting-static or dynamic. CONCLUSIONS: Good predictive ability of influenza epidemics is critical for implementing mitigation strategies in an effective and timely manner. Through the process of predictive validation applied to a current complex simulation model of influenza spread, we provided users of the model (e.g. public-health officials and policy-makers with quantitative metrics and practical recommendations on mitigating impacts of seasonal influenza epidemics. This methodology may be applied to other models of communicable infectious diseases to test and potentially improve

  15. Vectorised Spreading Activation algorithm for centrality measurement

    Directory of Open Access Journals (Sweden)

    Alexander Troussov

    2011-01-01

    Full Text Available Spreading Activation is a family of graph-based algorithms widely used in areas such as information retrieval, epidemic models, and recommender systems. In this paper we introduce a novel Spreading Activation (SA method that we call Vectorised Spreading Activation (VSA. VSA algorithms, like “traditional” SA algorithms, iteratively propagate the activation from the initially activated set of nodes to the other nodes in a network through outward links. The level of the node’s activation could be used as a centrality measurement in accordance with dynamic model-based view of centrality that focuses on the outcomes for nodes in a network where something is flowing from node to node across the edges. Representing the activation by vectors allows the use of the information about various dimensionalities of the flow and the dynamic of the flow. In this capacity, VSA algorithms can model multitude of complex multidimensional network flows. We present the results of numerical simulations on small synthetic social networks and multi­dimensional network models of folksonomies which show that the results of VSA propagation are more sensitive to the positions of the initial seed and to the community structure of the network than the results produced by traditional SA algorithms. We tentatively conclude that the VSA methods could be instrumental to develop scalable and computationally efficient algorithms which could achieve synergy between computation of centrality indexes with detection of community structures in networks. Based on our preliminary results and on improvements made over previous studies, we foresee advances and applications in the current state of the art of this family of algorithms and their applications to centrality measurement.

  16. Predictive Validation of an Influenza Spread Model

    Science.gov (United States)

    Hyder, Ayaz; Buckeridge, David L.; Leung, Brian

    2013-01-01

    Background Modeling plays a critical role in mitigating impacts of seasonal influenza epidemics. Complex simulation models are currently at the forefront of evaluating optimal mitigation strategies at multiple scales and levels of organization. Given their evaluative role, these models remain limited in their ability to predict and forecast future epidemics leading some researchers and public-health practitioners to question their usefulness. The objective of this study is to evaluate the predictive ability of an existing complex simulation model of influenza spread. Methods and Findings We used extensive data on past epidemics to demonstrate the process of predictive validation. This involved generalizing an individual-based model for influenza spread and fitting it to laboratory-confirmed influenza infection data from a single observed epidemic (1998–1999). Next, we used the fitted model and modified two of its parameters based on data on real-world perturbations (vaccination coverage by age group and strain type). Simulating epidemics under these changes allowed us to estimate the deviation/error between the expected epidemic curve under perturbation and observed epidemics taking place from 1999 to 2006. Our model was able to forecast absolute intensity and epidemic peak week several weeks earlier with reasonable reliability and depended on the method of forecasting-static or dynamic. Conclusions Good predictive ability of influenza epidemics is critical for implementing mitigation strategies in an effective and timely manner. Through the process of predictive validation applied to a current complex simulation model of influenza spread, we provided users of the model (e.g. public-health officials and policy-makers) with quantitative metrics and practical recommendations on mitigating impacts of seasonal influenza epidemics. This methodology may be applied to other models of communicable infectious diseases to test and potentially improve their predictive

  17. Clinical evaluation of whole-body oncologic PET with time-of-flight and point-spread function for the hybrid PET/MR system.

    Science.gov (United States)

    Shang, Kun; Cui, Bixiao; Ma, Jie; Shuai, Dongmei; Liang, Zhigang; Jansen, Floris; Zhou, Yun; Lu, Jie; Zhao, Guoguang

    2017-08-01

    Hybrid positron emission tomography/magnetic resonance (PET/MR) imaging is a new multimodality imaging technology that can provide structural and functional information simultaneously. The aim of this study was to investigate the effects of the time-of-flight (TOF) and point-spread function (PSF) on small lesions observed in PET/MR images from clinical patient image sets. This study evaluated 54 small lesions in 14 patients who had undergone 18 F-fluorodeoxyglucose (FDG) PET/MR. Lesions up to 30mm in diameter were included. The PET data were reconstructed with a baseline ordered-subsets expectation-maximization (OSEM) algorithm, OSEM+PSF, OSEM+TOF and OSEM+TOF+PSF. PET image quality and small lesions were visually evaluated and scored by a 3-point scale. A quantitative analysis was then performed using the mean and maximum standardized uptake value (SUV) of the small lesions (SUV mean and SUV max ). The lesions were divided into two groups according to the long-axis diameter and the location respectively and evaluated with each reconstruction algorithm. We also evaluated the background signal by analyzing the SUV liver . OSEM+TOF+PSF provided the highest value and OSEM+TOF or PSF showed a higher value than OSEM for the visual assessment and quantitative analysis. The combination of TOF and PSF increased the SUV mean by 26.6% and the SUV max by 30.0%. The SUV liver was not influenced by PSF or TOF. For the OSEM+TOF+PSF model, the change in SUV mean and SUV max for lesions PET/MR images, potentially improving small lesion detectability. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Mesoscale eddies in the Gulf of Aden and their impact on the spreading of Red Sea Outflow Water

    Science.gov (United States)

    Bower, Amy S.; Furey, Heather H.

    2012-04-01

    The Gulf of Aden (GOA) in the northwestern Indian Ocean is the receiving basin for Red Sea Outflow Water (RSOW), one of the World’s few high-salinity dense overflows, but relatively little is known about spreading pathways and transformation of RSOW through the gulf. Here we combine historical data, satellite altimetry, new synoptic hydrographic surveys and the first in situ direct observations of subsurface currents in the GOA to identify the most important processes in the spreading of RSOW. The new in situ data sets were collected in 2001-2003 as part of the Red Sea Outflow Experiment (REDSOX) and consist of two CTD/LADCP Surveys and 49 one-year trajectories from acoustically tracked floats released at the depth of RSOW. The results indicate that the prominent positive and negative sea level anomalies frequently observed in the GOA with satellite altimetry are associated with anticyclonic and cyclonic eddies that often reach to at least 1000 m depth, i.e., through the depth range of equilibrated RSOW. The eddies dominate RSOW spreading pathways and help to rapidly mix the outflow water with the background. Eddies in the central and eastern gulf are basin-scale (∼250-km diameter) and have maximum azimuthal speeds of about 30 cm/s at the RSOW level. In the western gulf, smaller eddies not detectable with satellite altimetry appear to form as the larger westward-propagating eddies impale themselves on the high ridges flanking the Tadjura Rift. Both the hydrographic and Lagrangian observations show that eddies originating outside the gulf often transport a core of much cooler, fresher water from the Arabian Sea all the way to the western end of the GOA, where the highest-salinity outflow water is found. This generates large vertical and horizontal gradients of temperature and salinity, setting up favorable conditions for salt fingering and diffusive convection. Both of these mixing processes were observed to be active in the gulf. Two new annually appearing

  19. Directional spread parameter at intermediate water depth

    Digital Repository Service at National Institute of Oceanography (India)

    SanilKumar, V.; Deo, M.C.; Anand, N.M.; AshokKumar, K.

    ’ involves only the significant wave height, zero crossing wave period and water depth, the spreading function based on ‘s 3 ’ can be used for practical appli- cation. In the model based on ‘s 3 ’ the mean wave direction is an input and this has...-linearity parameter can be recommended for practical use as it provides an averaged distribution. Acknowledgements The authors would like to thank the Department of Science and Technology, New Delhi, for funding the project titled “Directional wave modelling...

  20. Trigeminal perineural spread of renal cell carcinoma

    International Nuclear Information System (INIS)

    Hornik, Alejandro; Rosenblum, Jordan; Biller, Jose

    2012-01-01

    A 55-year-old man had a five-day history of “pins and needles” sensation on the left chin. Examination showed decreased pinprick sensation on the territory of the left mandibular branch of the trigeminal nerve. Brain magnetic resonance imaging (MRI) with gadolinium showed enhancement involving the left mandibular branch. Computed tomography (CT) of the chest, abdomen, and pelvis showed a left kidney mass diagnosed as renal carcinoma following nephrectomy. The “numb-chin” syndrome heralds or accompanies systemic malignancies. Trigeminal perineural spread has been well-documented in head and neck neoplasms, however, to our knowledge, it has not been reported in renal neoplasms. (author)

  1. Dynamic Modeling of CDS Index Tranche Spreads

    DEFF Research Database (Denmark)

    Dorn, Jochen

    This paper provides a Market Model which implies a dynamics for standardized CDS index tranche spreads, i.e. tranches which securitise CDS index series and dispose of predefined subordination. This model is useful for pricing options on tranches with future Issue Dates as well as for modeling...... options on structured credit derivatives. With the upcoming regulation of the CDS market in perspective, the model presented here is also an attempt to face the effects on pricing approaches provoked by an eventual Clearing Chamber . It becomes also possible to calibrate Index Tranche Options with bespoke...... tenors/tranche subordination to market data obtained by more liquid Index Tranche Options with standard characteristics....

  2. Prediction and error of baldcypress stem volume from stump diameter

    Science.gov (United States)

    Bernard R. Parresol

    1998-01-01

    The need to estimate the volume of removals occurs for many reasons, such as in trespass cases, severance tax reports, and post-harvest assessments. A logarithmic model is presented for prediction of baldcypress total stem cubic foot volume using stump diameter as the independent variable. Because the error of prediction is as important as the volume estimate, the...

  3. Changes in intraocular pressure and horizontal pupil diameter ...

    African Journals Online (AJOL)

    The objective of this study was to determine the effects of topical 0.5% tropicamide, 1% atropine sulphate and 10% phenylephrine hydrochloride ophthalmic solutions on intraocular pressure (IOP) and horizontal pupil diameter (HPD) in the dog during the first hour after treatment. Forty clinically and ophthalmologically ...

  4. Study of tube diameter effect on the burnout

    International Nuclear Information System (INIS)

    Levitan, L.L.; Lantsman, F.P.; Dedneva, E.I.

    1981-01-01

    Effect of a tube diameter d on boundary steam content Xsub(b) is experimentally investigated during unwashed liquid wall film drying in the disperse-ring flow regime. For this purpose systematical experimental investigations of the burnout of the second kind in tubes with diameters of 4, 6 and 12 mm have been carried out as well as the other data relating to burnout in tubes with diameter from 4 to 40 mm are used. The investigations have been carried out at water and steam pressures of 4.9-13.7 MPa and mass velocities from 750 to 5000 kg/m 2 xs. It is elucidated that increase in the tube diameter results in reducing the ranges of pressures and mass velocities at which Xsub(b) is independent of heat flux. Quantity dependence Xsub(b)=f(d) has been obtained as well. The best agreement with data from different experiments is observed when taking into account the effect of d on Xsub(b) by means of the following relation: Xsub(b) is proportional to dsup(-0.25). In this case divergence, as a rule, does not exceed 10% [ru

  5. Historical perspective on diameter-limit cutting in northeastern forests

    Science.gov (United States)

    Matthew J. Kelty; Anthony W. D' Amato; Anthony W. D' Amato

    2006-01-01

    The use of diameter-limit cutting and high-grading is currently a concern for long-term sustainability of forests in the Northeastern United States and surrounding areas. This paper reviews historical information about the kinds of harvesting used in this region from 1620 to 1950, to provide a context for current discussions. Throughout this period, most timber...

  6. Variations in eyeball diameters of the healthy adults.

    Science.gov (United States)

    Bekerman, Inessa; Gottlieb, Paul; Vaiman, Michael

    2014-01-01

    The purpose of the current research was to reevaluate the normative data on the eyeball diameters. Methods. In a prospective cohort study, the CT data of consecutive 250 adults with healthy eyes were collected and analyzed, and sagittal, transverse, and axial diameters of both eyeballs were measured. The data obtained from the left eye and from the right eye were compared. The correlation analysis was performed with the following variables: orbit size, gender, age, and ethnic background. Results. We did not find statistically significant differences correlated with gender of the patients and their age. The right eyeball was slightly smaller than the left one but this difference was statistically insignificant (P = 0.17). We did not find statistically significant differences of the eyeball sizes among the ethnicities we dealt with. Strong correlation was found between the transverse diameter and the width of the orbit (r = 0.88). Conclusion. The size of a human adult eye is approximately 24.2 mm (transverse) × 23.7 mm (sagittal) × 22.0-24.8 mm (axial) with no significant difference between sexes and age groups. In the transverse diameter, the eyeball size may vary from 21 mm to 27 mm. These data might be useful in ophthalmological, oculoplastic, and neurological practice.

  7. Mountain pine beetle infestations in relation to lodgepole pine diameters

    Science.gov (United States)

    Walter E. Cole; Gene D. Amman

    1969-01-01

    Tree losses resulting from infestation by the mountain pine beetle (Dendroctonus ponderosae Hopkins) were measured in two stands of lodgepole pine (Pinus contorta Dougl.) where the beetle population had previously been epidemic. Measurement data showed that larger diameter trees were infested and killed first. Tree losses...

  8. 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...

  9. Sonographic assessment of the portal vein diameter in apparently ...

    African Journals Online (AJOL)

    the head in Frankfurts' position and weight measured using a weighing scale. ... 1.41mm and that PV diameter positively correlates with anthropometric variables. ... time consuming and involve risk and discomfort to the .... tolic velocity which gives an accurate and a reliable meth- .... a tertiary care centre in North-East India.

  10. Uncertainty budget for optical coordinate measurements of circle diameter

    DEFF Research Database (Denmark)

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

    2004-01-01

    An uncertainty analysis for circle diameter measurements using a coordinate measuring machine (CMM) equipped with an optical probe is presented in this paper. A mathematical model for data evaluation and uncertainty assessment was formulated in accordance with Guide to the Expression of Uncertain...

  11. Arterial diameter during central volume depletion in humans

    DEFF Research Database (Denmark)

    Iversen, Helle Klingenberg; Madsen, P; Matzen, S

    1995-01-01

    The luminal diameter of the radial artery was followed by high frequency ultrasound during 50 degrees head-up tilt-induced central volume depletion in ten healthy subjects of whom six were tilted twice and pretreated with the serotonin receptor antagonist methysergide or placebo following a double...

  12. 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.

  13. Bipartite Diametrical Graphs of Diameter 4 and Extreme Orders

    Directory of Open Access Journals (Sweden)

    Salah Al-Addasi

    2008-01-01

    in which this upper bound is attained, this graph can be viewed as a generalization of the Rhombic Dodecahedron. Then we show that for any ≥2, the graph (2,2 is the unique (up to isomorphism bipartite diametrical graph of diameter 4 and partite sets of cardinalities 2 and 2, and hence in particular, for =3, the graph (6,8 which is just the Rhombic Dodecahedron is the unique (up to isomorphism bipartite diametrical graph of such a diameter and cardinalities of partite sets. Thus we complete a characterization of -graphs of diameter 4 and cardinality of the smaller partite set not exceeding 6. We prove that the neighborhoods of vertices of the larger partite set of (2,2 form a matroid whose basis graph is the hypercube . We prove that any -graph of diameter 4 is bipartite self complementary, thus in particular (2,2. Finally, we study some additional properties of (2,2 concerning the order of its automorphism group, girth, domination number, and when being Eulerian.

  14. NEOWISE Reactivation Mission Year Three: Asteroid Diameters and Albedos

    Energy Technology Data Exchange (ETDEWEB)

    Masiero, Joseph R.; Mainzer, A. K.; Kramer, E. [Jet Propulsion Laboratory/California Institute of Technology, 4800 Oak Grove Drive, MS 183-301, Pasadena, CA 91109 (United States); Nugent, C.; Cutri, R. M. [California Institute of Technology, Infrared Processing and Analysis Center, 1200 California Boulevard, Pasadena, CA 91125 (United States); Wright, E. L. [University of California, Los Angeles, CA 90095 (United States); Bauer, J. M. [University of Maryland, College Park, MD 20742 (United States); Grav, T.; Sonnett, S., E-mail: Joseph.Masiero@jpl.nasa.gov [Planetary Science Institute, 1700 E Fort Lowell Road #106, Tucson, AZ 85719 (United States)

    2017-10-01

    The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) reactivation mission has completed its third year of surveying the sky in the thermal infrared for near-Earth asteroids and comets. NEOWISE collects simultaneous observations at 3.4 and 4.6  μ m of solar system objects passing through its field of regard. These data allow for the determination of total thermal emission from bodies in the inner solar system, and thus the sizes of these objects. In this paper, we present thermal model fits of asteroid diameters for 170 NEOs and 6110 Main Belt asteroids (MBAs) detected during the third year of the survey, as well as the associated optical geometric albedos. We compare our results with previous thermal model results from NEOWISE for overlapping sample sets, as well as diameters determined through other independent methods, and find that our diameter measurements for NEOs agree to within 26% (1 σ ) of previously measured values. Diameters for the MBAs are within 17% (1 σ ). This brings the total number of unique near-Earth objects characterized by the NEOWISE survey to 541, surpassing the number observed during the fully cryogenic mission in 2010.

  15. NEOWISE Reactivation Mission Year Three: Asteroid Diameters and Albedos

    International Nuclear Information System (INIS)

    Masiero, Joseph R.; Mainzer, A. K.; Kramer, E.; Nugent, C.; Cutri, R. M.; Wright, E. L.; Bauer, J. M.; Grav, T.; Sonnett, S.

    2017-01-01

    The Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) reactivation mission has completed its third year of surveying the sky in the thermal infrared for near-Earth asteroids and comets. NEOWISE collects simultaneous observations at 3.4 and 4.6  μ m of solar system objects passing through its field of regard. These data allow for the determination of total thermal emission from bodies in the inner solar system, and thus the sizes of these objects. In this paper, we present thermal model fits of asteroid diameters for 170 NEOs and 6110 Main Belt asteroids (MBAs) detected during the third year of the survey, as well as the associated optical geometric albedos. We compare our results with previous thermal model results from NEOWISE for overlapping sample sets, as well as diameters determined through other independent methods, and find that our diameter measurements for NEOs agree to within 26% (1 σ ) of previously measured values. Diameters for the MBAs are within 17% (1 σ ). This brings the total number of unique near-Earth objects characterized by the NEOWISE survey to 541, surpassing the number observed during the fully cryogenic mission in 2010.

  16. Laser beam diameter for port wine stain treatment

    NARCIS (Netherlands)

    Keijzer, M.; Pickering, J. W.; van Gemert, M. J.

    1991-01-01

    Optimal port wine stain treatment requires the selective absorption of light by the ectatic blood vessels. We investigated whether deeper blood vessels can be coagulated, without damaging other cutaneous structures, by varying the laser beam diameter. The penetration of the light was simulated with

  17. Pupil Center as a Function of Pupil Diameter

    DEFF Research Database (Denmark)

    Ahmed, Zaheer; Mardanbegi, Diako; Hansen, Dan Witzner

    2016-01-01

    We investigate the gaze estimation error induced by pupil size changes using simulated data. We investigate the influence of pupil diameter changes on estimated gaze point error obtained by two gaze estimation models. Simulation data show that at wider viewing angles and at small eye...

  18. Stem diameter and height of chrysanthemum cv Yoko ono as ...

    African Journals Online (AJOL)

    Administrator

    2011-09-26

    Sep 26, 2011 ... Booij R (1989). Effect of growth regulators on curd diameter of cauliflower. Sci. Hortic. 38: 23-32. Castro PRC (1998). Use of plant growth regulators in fruit production of vegetable crops and ornamental plants. Série produtor Rural, Ed. especial, Piracicaba: ESALQ- Divisão de Biblioteca e Documentação.

  19. FACES WITH LARGE DIAMETER ON THE SYMMETRICAL TRAVELING SALESMAN POLYTOPE

    NARCIS (Netherlands)

    SIERKSMA, G; TIJSSEN, GA

    This paper deals with the symmetric traveling salesman polytope and contains three main theorems. The first one gives a new characterization of (non)adjacency. Based on this characterization a new upper bound for the diameter of the symmetric traveling salesman polytope (conjectured to be 2 by M.

  20. Numerical analysis of the bubble detachment diameter in nucleate boiling

    International Nuclear Information System (INIS)

    Lamas, M I; Sáiz Jabardo, J M; Arce, A; Fariñas, P

    2012-01-01

    The present paper presents a tri-dimensional CFD (Computational Fluid Dynamics) model to investigate the fluid flow around bubbles attached to heated walls. Transient solutions of the governing field equations in a domain containing the bubbles and the surrounding liquid have been obtained. The nucleation, growing and detachment processes have been analyzed. Concerning the software, the open source OpenFOAM has been used. Special attention has been given to the bubble detachment diameter. Two mechanisms have been considered as physically related to the detachment: surface tension and buoyancy. As expected, it has been verified that the bubble detachment diameter depends on the contact angle, operating pressure and properties of the fluid. Several fluids have been considered (water, R134a, ammonia and R123), as well as several operating pressures (between 0.1 and 10 bar) and contact angles (between 10 and 80°). It has been concluded that the detachment diameter depends strongly on the contact angle and fluid properties and slightly on the pressure. A correlation for the bubble detachment diameter has been developed based on the obtained numerical results. Data from this expression compare reasonably well with those from other correlations from the literature.

  1. Height-diameter allometry of tropical forest trees

    Science.gov (United States)

    T.R. Feldpausch; L. Banin; O.L. Phillips; T.R. Baker; S.L. Lewis; C.A. Quesada; K. Affum-Baffoe; E.J.M.M. Arets; N.J. Berry; M. Bird; E.S. Brondizio; P de Camargo; J. Chave; G. Djagbletey; T.F. Domingues; M. Drescher; P.M. Fearnside; M.B. Franca; N.M. Fyllas; G. Lopez-Gonzalez; A. Hladik; N. Higuchi; M.O. Hunter; Y. Iida; K.A. Salim; A.R. Kassim; M. Keller; J. Kemp; D.A. King; J.C. Lovett; B.S. Marimon; B.H. Marimon-Junior; E. Lenza; A.R. Marshall; D.J. Metcalfe; E.T.A. Mitchard; E.F. Moran; B.W. Nelson; R. Nilus; E.M. Nogueira; M. Palace; S. Patiño; K.S.-H. Peh; M.T. Raventos; J.M. Reitsma; G. Saiz; F. Schrodt; B. Sonke; H.E. Taedoumg; S. Tan; L. White; H. Woll; J. Lloyd

    2011-01-01

    Tropical tree height-diameter (H:D) relationships may vary by forest type and region making large-scale estimates of above-ground biomass subject to bias if they ignore these differences in stem allometry. We have therefore developed a new global tropical forest database consisting of 39 955 concurrent H and D measurements encompassing 283 sites in 22 tropical...

  2. Definition of Beam Diameter for Electron Beam Welding

    Energy Technology Data Exchange (ETDEWEB)

    Burgardt, Paul [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pierce, Stanley W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Dvornak, Matthew John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-03-11

    It is useful to characterize the dimensions of the electron beam during process development for electron beam welding applications. Analysis of the behavior of electron beam welds is simplest when a single number can be assigned to the beam properties that describes the size of the beam spot; this value we generically call the “beam diameter”. This approach has worked well for most applications and electron beam welding machines with the weld dimensions (width and depth) correlating well with the beam diameter. However, in recent weld development for a refractory alloy, Ta-10W, welded with a low voltage electron beam machine (LVEB), it was found that the weld dimensions (weld penetration and weld width) did not correlate well with the beam diameter and especially with the experimentally determined sharp focus point. These data suggest that the presently used definition of beam diameter may not be optimal for all applications. The possible reasons for this discrepancy and a suggested possible alternative diameter definition is the subject of this paper.

  3. Diameter sensors for tree-length harvesting systems

    Science.gov (United States)

    T.P. McDonald; Robert B. Rummer; T.E. Grift

    2003-01-01

    Most cut-to-length (CTL) harvesters provide sensors for measuring diameter of trees as they are cut and processed. Among other uses, this capability provides a data collection tool for marketing of logs in real time. Logs can be sorted and stacked based on up-to-date market information, then transportation systems optimized to route wood to proper destinations at...

  4. Percentile-based Weibull diameter distribution model for Pinus ...

    African Journals Online (AJOL)

    Using a site index equation and stem volume model developed for Pinus kesiya in the Philippines, a yield prediction system was created to predict the volume per ha (VPH) for each diameter class and, subsequently, the total volume of a stand. To evaluate the yield prediction system, the predicted mean VPH for each ...

  5. Maximum support resistance with steel arch backfilling

    Energy Technology Data Exchange (ETDEWEB)

    1983-01-01

    A system of backfilling for roadway arch supports to replace timber and debris lagging is described. Produced in West Germany, it is known as the Bullflex system and consists of 23 cm diameter woven textile tubing which is inflated with a pumpable hydraulically-setting filler of the type normally used in mines. The tube is placed between the back of the support units and the rock face and creates an early-stage interlocking effect.

  6. Catastrophic Disruption Threshold and Maximum Deflection from Kinetic Impact

    Science.gov (United States)

    Cheng, A. F.

    2017-12-01

    The use of a kinetic impactor to deflect an asteroid on a collision course with Earth was described in the NASA Near-Earth Object Survey and Deflection Analysis of Alternatives (2007) as the most mature approach for asteroid deflection and mitigation. The NASA DART mission will demonstrate asteroid deflection by kinetic impact at the Potentially Hazardous Asteroid 65803 Didymos in October, 2022. The kinetic impactor approach is considered to be applicable with warning times of 10 years or more and with hazardous asteroid diameters of 400 m or less. In principle, a larger kinetic impactor bringing greater kinetic energy could cause a larger deflection, but input of excessive kinetic energy will cause catastrophic disruption of the target, leaving possibly large fragments still on collision course with Earth. Thus the catastrophic disruption threshold limits the maximum deflection from a kinetic impactor. An often-cited rule of thumb states that the maximum deflection is 0.1 times the escape velocity before the target will be disrupted. It turns out this rule of thumb does not work well. A comparison to numerical simulation results shows that a similar rule applies in the gravity limit, for large targets more than 300 m, where the maximum deflection is roughly the escape velocity at momentum enhancement factor β=2. In the gravity limit, the rule of thumb corresponds to pure momentum coupling (μ=1/3), but simulations find a slightly different scaling μ=0.43. In the smaller target size range that kinetic impactors would apply to, the catastrophic disruption limit is strength-controlled. A DART-like impactor won't disrupt any target asteroid down to significantly smaller size than the 50 m below which a hazardous object would not penetrate the atmosphere in any case unless it is unusually strong.

  7. Multi-diameter pigging: factors affecting the design and selection of pigging tools for multi-diameter pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Dawson, Karl [Pipeline Engineering and Supply Co. Ltd., Richmond, NY (United States)

    2009-07-01

    This paper will consider the process involved in pigging tool selection for pipelines with two or more significant internal diameters which require pigging tools capable of negotiating the different internal diameters whilst also carrying out the necessary pipeline cleaning operation. The paper will include an analysis of pipeline features that affect pigging tool selection and then go on to look at other variables that determine the pigging tool design; this will include a step by step guide outlining how the tool is designed, the development of prototype pigs and the importance of testing and validation prior to final deployment in operational pigging programmes. (author)

  8. Corrosion and deposit determination in large diameter pipes by radiography

    International Nuclear Information System (INIS)

    Harara, W.

    2006-08-01

    Two steel reference pipes with outer diameters of 8 and 12 inches were machined to make artificial defects on each of them, such as inside and outside steps of different wall thicknesses, inside and outside flat bottomed holes (FBH) of different diameters and depths on steps, flat area (FA), and ground patch (GP). The artificial defect were made to simulate natural corrosion attack as regular corrosion and pitting. The two reference pipes were tested according to tangential radiography technique and double wall single image technique. Tangential radiography technique had been applied using Co-60 radio-isotope to determine the steps thicknesses, the FBH, the remaining wall thickness under the FA, the remaining wall thickness above the GP, and the minimum detectable thickness of the artificial cement deposit on the two reference pipes, with and without insulation. Double wall single image technique had also been applied on the two reference pipes with and without insulation using Ir-192 radio-isotope to measure the flat bottomed holes depths, GP depth, and FA depth by density measurement. The measurement results obtained from the radiographs confirm that, tangential radiography technique can be applied to detect and evaluate the inside and outside regular corrosion attack in the large diameter pipes. It can also be applied to detect and evaluate the outside FBH with depth equal or greater than 10%. Inside 10% FBH and inside 20% FBH can not be detected if their diameters are not larger than certain value related to diameter and wall thickness of the pipe under test. Increasing the film density up to 5 outside the pipe did not provide any detection improvement of 10% and 20% inside FBH. Tangential radiography technique can also be applied to detect and measure the deposit inside the pipes. Double wall technique can be applied as an alternative method of the tangential radiography technique to detect and to evaluate the shallow and small diameter, 10% and 20% inside FBH

  9. The AKARI IRC asteroid flux catalogue: updated diameters and albedos

    Science.gov (United States)

    Alí-Lagoa, V.; Müller, T. G.; Usui, F.; Hasegawa, S.

    2018-05-01

    The AKARI IRC all-sky survey provided more than twenty thousand thermal infrared observations of over five thousand asteroids. Diameters and albedos were obtained by fitting an empirically calibrated version of the standard thermal model to these data. After the publication of the flux catalogue in October 2016, our aim here is to present the AKARI IRC all-sky survey data and discuss valuable scientific applications in the field of small body physical properties studies. As an example, we update the catalogue of asteroid diameters and albedos based on AKARI using the near-Earth asteroid thermal model (NEATM). We fit the NEATM to derive asteroid diameters and, whenever possible, infrared beaming parameters. We fit groups of observations taken for the same object at different epochs of the survey separately, so we compute more than one diameter for approximately half of the catalogue. We obtained a total of 8097 diameters and albedos for 5170 asteroids, and we fitted the beaming parameter for almost two thousand of them. When it was not possible to fit the beaming parameter, we used a straight line fit to our sample's beaming parameter-versus-phase angle plot to set the default value for each fit individually instead of using a single average value. Our diameters agree with stellar-occultation-based diameters well within the accuracy expected for the model. They also match the previous AKARI-based catalogue at phase angles lower than 50°, but we find a systematic deviation at higher phase angles, at which near-Earth and Mars-crossing asteroids were observed. The AKARI IRC All-sky survey is an essential source of information about asteroids, especially the large ones, since, it provides observations at different observation geometries, rotational coverages and aspect angles. For example, by comparing in more detail a few asteroids for which dimensions were derived from occultations, we discuss how the multiple observations per object may already provide three

  10. Infections Unlikely to be Spread Through Swimming Pools

    Science.gov (United States)

    ... Water Home Infections Unlikely to be Spread Through Swimming Pools Language: English (US) Español (Spanish) Recommend on ... included below. Infections Unlikely to be Spread by Swimming Pools Head Lice Head lice are unlikely to ...

  11. Spreading depolarisations and outcome after traumatic brain injury

    DEFF Research Database (Denmark)

    Hartings, Jed A; Bullock, M Ross; Okonkwo, David O

    2011-01-01

    Pathological waves of spreading mass neuronal depolarisation arise repeatedly in injured, but potentially salvageable, grey matter in 50-60% of patients after traumatic brain injury (TBI). We aimed to ascertain whether spreading depolarisations are independently associated with unfavourable...

  12. Stopping the Spread of Germs at Home, Work and School

    Science.gov (United States)

    ... Pandemic Other Stopping the Spread of Germs at Home, Work & School Language: English (US) Español Recommend on Facebook ... everyone from getting germs or spreading germs at home, work, or school. Clean and disinfect surfaces or objects. ...

  13. Recording, analysis, and interpretation of spreading depolarizations in neurointensive care

    DEFF Research Database (Denmark)

    Dreier, Jens P; Fabricius, Martin; Ayata, Cenk

    2017-01-01

    Spreading depolarizations (SD) are waves of abrupt, near-complete breakdown of neuronal transmembrane ion gradients, are the largest possible pathophysiologic disruption of viable cerebral gray matter, and are a crucial mechanism of lesion development. Spreading depolarizations are increasingly r...

  14. Measurement error in CT assessment of appendix diameter

    Energy Technology Data Exchange (ETDEWEB)

    Trout, Andrew T.; Towbin, Alexander J. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, MLC 5031, Cincinnati, OH (United States); Zhang, Bin [Cincinnati Children' s Hospital Medical Center, Department of Biostatistics and Epidemiology, Cincinnati, OH (United States)

    2016-12-15

    Appendiceal diameter continues to be cited as an important criterion for diagnosis of appendicitis by computed tomography (CT). To assess sources of error and variability in appendiceal diameter measurements by CT. In this institutional review board-approved review of imaging and medical records, we reviewed CTs performed in children <18 years of age between Jan. 1 and Dec. 31, 2010. Appendiceal diameter was measured in the axial and coronal planes by two reviewers (R1, R2). One year later, 10% of cases were remeasured. For patients who had multiple CTs, serial measurements were made to assess within patient variability. Measurement differences between planes, within and between reviewers, within patients and between CT and pathological measurements were assessed using correlation coefficients and paired t-tests. Six hundred thirty-one CTs performed in 519 patients (mean age: 10.9 ± 4.9 years, 50.8% female) were reviewed. Axial and coronal measurements were strongly correlated (r = 0.92-0.94, P < 0.0001) with coronal plane measurements significantly larger (P < 0.0001). Measurements were strongly correlated between reviewers (r = 0.89-0.9, P < 0.0001) but differed significantly in both planes (axial: +0.2 mm, P=0.003; coronal: +0.1 mm, P=0.007). Repeat measurements were significantly different for one reviewer only in the axial plane (0.3 mm difference, P<0.05). Within patients imaged multiple times, measured appendix diameters differed significantly in the axial plane for both reviewers (R1: 0.5 mm, P = 0.031; R2: 0.7 mm, P = 0.022). Multiple potential sources of measurement error raise concern about the use of rigid diameter cutoffs for the diagnosis of acute appendicitis by CT. (orig.)

  15. Nuclear criticality safety calculational analysis for small-diameter containers

    International Nuclear Information System (INIS)

    LeTellier, M.S.; Smallwood, D.J.; Henkel, J.A.

    1995-11-01

    This report documents calculations performed to establish a technical basis for the nuclear criticality safety of favorable geometry containers, sometimes referred to as 5-inch containers, in use at the Portsmouth Gaseous Diffusion Plant. A list of containers currently used in the plant is shown in Table 1.0-1. These containers are currently used throughout the plant with no mass limits. The use of containers with geometries or material types other than those addressed in this evaluation must be bounded by this analysis or have an additional analysis performed. The following five basic container geometries were modeled and bound all container geometries in Table 1.0-1: (1) 4.32-inch-diameter by 50-inch-high polyethylene bottle; (2) 5.0-inch-diameter by 24-inch-high polyethylene bottle; (3) 5.25-inch-diameter by 24-inch-high steel can (open-quotes F-canclose quotes); (4) 5.25-inch-diameter by 15-inch-high steel can (open-quotes Z-canclose quotes); and (5) 5.0-inch-diameter by 9-inch-high polybottle (open-quotes CO-4close quotes). Each container type is evaluated using five basic reflection and interaction models that include single containers and multiple containers in normal and in credible abnormal conditions. The uranium materials evaluated are UO 2 F 2 +H 2 O and UF 4 +oil materials at 100% and 10% enrichments and U 3 O 8 , and H 2 O at 100% enrichment. The design basis safe criticality limit for the Portsmouth facility is k eff + 2σ < 0.95. The KENO study results may be used as the basis for evaluating general use of these containers in the plant

  16. Vertebral Artery Diameter and Flow: Nature or Nurture.

    Science.gov (United States)

    Tarnoki, Adam Domonkos; Fejer, Bence; Tarnoki, David Laszlo; Littvay, Levente; Lucatelli, Pierleone; Cirelli, Carlo; Fanelli, Fabrizio; Sacconi, Beatrice; Fagnani, Corrado; Medda, Emanuela; Farina, Filippo; Meneghetti, Giorgio; Horvath, Tamas; Pucci, Giacomo; Schillaci, Giuseppe; Stazi, Maria Antonietta; Baracchini, Claudio

    2017-09-01

    In contrast with the carotid arteries, the vertebral arteries (VAs) show considerable variation in length, caliber, and vessel course. This study investigated whether the variation in diameter and flow characteristics of the VAs might be inherited. A total of 172 Italian twins from Padua, Perugia, and Terni (54 monozygotic, 32 dizygotic) recruited from the Italian Twin Registry underwent B-mode and pulsed-wave Doppler ultrasound assessment of their VAs. VA diameters, peak systolic velocity (PSV) and end diastolic velocity (EDV) were assessed at the level of a horizontal V2 segment. Univariate quantitative genetic modeling was performed. Fourteen percent of the sample had VA hypoplasia. Within pair correlation in monozygotic twins was higher than in dizygotics (.552 vs. .229) for VA diameter. Age- and sex-adjusted genetic effect, under the most parsimonious model, accounted for 54.7% (95% CI: 42.2-69.1%) of the variance of VA diameter, and unshared environmental effect for 45.3% (95% CI: 30.9-57.8%). No heritability was found for the PSV of VA, but shared (34.1%; 95% CI: 16.7-53.7%) and unshared (65.9%; 95% CI: 45.9-83.1%) environmental factors determined the variance. EDV of VA is moderately genetically influenced (42.4%; 95% CI: 16.1-64.9%) and also determined by the unshared environment (57.6%; 95% CI: 34.7-83.7%). The diameter of the VAs is moderately genetically determined. Different factors influence the PSV and EDV of VAs, which may highlight the complex hemodynamic background of VA flow and help to understand the vertebral flow anomalies found by ultrasound. Copyright © 2017 by the American Society of Neuroimaging.

  17. Preoperative evaluation of locally spreaded pelvic tumors

    International Nuclear Information System (INIS)

    Baramia, M.; Todua, F.; Gotsadze, D.; Khutulashvili, N.; Lashkhi, K.; Nadareishvili, A.

    1998-01-01

    Am of the study: preoperative evaluation of patients with locally advanced pelvic tumors subjected to pelvic exenteration. Determine operability to avoid explorative laparatomies, which cause serious complications in these patients. Evaluate condition of urinary system in case of this pathology. Materials and methods: 34 patients with locally advanced pelvic tumors where pelvic exenteration was attempted were studied. Along with other methods of diagnostic CT and MRI were performed. Results: In all patients secondary involvement of the urinary bladder was noted. In 30 patients CT and MR findings were confirmed (88,2%) intraoperatively and different types of pelvic organs exenteration were performed. In 1 case spread of tomoruos infiltrate to the pelvic wall and common iliac vessels was detected intraoperatively (patient had history of radiation therapy). In 2 cases carcinomatosis of the peritoneum was found. In 1 case involvement of urinary bladder was simulated by close attachment of enlarged uterus. Conclusion: Obtained results show, that CT and MR are highly informative methods of disease spread evaluation and thus determining operability. Radiotherapy performed prior to operation sets difficulties in differentiation for tumourous infiltrate and post-radiotherapy changes in pelvis. (Full text)

  18. A lattice model for influenza spreading.

    Directory of Open Access Journals (Sweden)

    Antonella Liccardo

    Full Text Available We construct a stochastic SIR model for influenza spreading on a D-dimensional lattice, which represents the dynamic contact network of individuals. An age distributed population is placed on the lattice and moves on it. The displacement from a site to a nearest neighbor empty site, allows individuals to change the number and identities of their contacts. The dynamics on the lattice is governed by an attractive interaction between individuals belonging to the same age-class. The parameters, which regulate the pattern dynamics, are fixed fitting the data on the age-dependent daily contact numbers, furnished by the Polymod survey. A simple SIR transmission model with a nearest neighbors interaction and some very basic adaptive mobility restrictions complete the model. The model is validated against the age-distributed Italian epidemiological data for the influenza A(H1N1 during the [Formula: see text] season, with sensible predictions for the epidemiological parameters. For an appropriate topology of the lattice, we find that, whenever the accordance between the contact patterns of the model and the Polymod data is satisfactory, there is a good agreement between the numerical and the experimental epidemiological data. This result shows how rich is the information encoded in the average contact patterns of individuals, with respect to the analysis of the epidemic spreading of an infectious disease.

  19. Principles of spread-spectrum communication systems

    CERN Document Server

    Torrieri, Don

    2015-01-01

    This book provides a concise but lucid explanation of the fundamentals of spread-spectrum systems with an emphasis on theoretical principles. The choice of specific topics is tempered by the author’s judgment of their practical significance and interest to both researchers and system designers. The book contains many improved derivations of the classical theory and presents the latest research results that bring the reader to the frontier of the field. This third edition includes new coverage of topics such as CDMA networks, acquisition and synchronization in DS-CDMA cellular networks, hopsets for FH-CDMA ad hoc networks, implications of information theory, the central limit theorem, the power spectral density of FH/CPM complex envelopes, adaptive filters, and adaptive arrays.   ·         Focuses on the fundamentals of spread-spectrum communication systems and provides current examples of their applications ·         Includes problem sets at the end of each chapter to assist readers in co...

  20. Wave-like spread of Ebola Zaire.

    Directory of Open Access Journals (Sweden)

    2005-11-01

    Full Text Available In the past decade the Zaire strain of Ebola virus (ZEBOV has emerged repeatedly into human populations in central Africa and caused massive die-offs of gorillas and chimpanzees. We tested the view that emergence events are independent and caused by ZEBOV variants that have been long resident at each locality. Phylogenetic analyses place the earliest known outbreak at Yambuku, Democratic Republic of Congo, very near to the root of the ZEBOV tree, suggesting that viruses causing all other known outbreaks evolved from a Yambuku-like virus after 1976. The tendency for earlier outbreaks to be directly ancestral to later outbreaks suggests that outbreaks are epidemiologically linked and may have occurred at the front of an advancing wave. While the ladder-like phylogenetic structure could also bear the signature of positive selection, our statistical power is too weak to reach a conclusion in this regard. Distances among outbreaks indicate a spread rate of about 50 km per year that remains consistent across spatial scales. Viral evolution is clocklike, and sequences show a high level of small-scale spatial structure. Genetic similarity decays with distance at roughly the same rate at all spatial scales. Our analyses suggest that ZEBOV has recently spread across the region rather than being long persistent at each outbreak locality. Controlling the impact of Ebola on wild apes and human populations may be more feasible than previously recognized.

  1. Epidemics spreading in interconnected complex networks

    International Nuclear Information System (INIS)

    Wang, Y.; Xiao, G.

    2012-01-01

    We study epidemic spreading in two interconnected complex networks. It is found that in our model the epidemic threshold of the interconnected network is always lower than that in any of the two component networks. Detailed theoretical analysis is proposed which allows quick and accurate calculations of epidemic threshold and average outbreak/epidemic size. Theoretical analysis and simulation results show that, generally speaking, the epidemic size is not significantly affected by the inter-network correlation. In interdependent networks which can be viewed as a special case of interconnected networks, however, impacts of inter-network correlation on the epidemic threshold and outbreak size are more significant. -- Highlights: ► We study epidemic spreading in two interconnected complex networks. ► The epidemic threshold is lower than that in any of the two networks. And Interconnection correlation has impacts on threshold and average outbreak size. ► Detailed theoretical analysis is proposed which allows quick and accurate calculations of epidemic threshold and average outbreak/epidemic size. ► We demonstrated and proved that Interconnection correlation does not affect epidemic size significantly. ► In interdependent networks, impacts of inter-network correlation on the epidemic threshold and outbreak size are more significant.

  2. Epidemic spreading on preferred degree adaptive networks.

    Science.gov (United States)

    Jolad, Shivakumar; Liu, Wenjia; Schmittmann, B; Zia, R K P

    2012-01-01

    We study the standard SIS model of epidemic spreading on networks where individuals have a fluctuating number of connections around a preferred degree κ. Using very simple rules for forming such preferred degree networks, we find some unusual statistical properties not found in familiar Erdös-Rényi or scale free networks. By letting κ depend on the fraction of infected individuals, we model the behavioral changes in response to how the extent of the epidemic is perceived. In our models, the behavioral adaptations can be either 'blind' or 'selective'--depending on whether a node adapts by cutting or adding links to randomly chosen partners or selectively, based on the state of the partner. For a frozen preferred network, we find that the infection threshold follows the heterogeneous mean field result λ(c)/μ = / and the phase diagram matches the predictions of the annealed adjacency matrix (AAM) approach. With 'blind' adaptations, although the epidemic threshold remains unchanged, the infection level is substantially affected, depending on the details of the adaptation. The 'selective' adaptive SIS models are most interesting. Both the threshold and the level of infection changes, controlled not only by how the adaptations are implemented but also how often the nodes cut/add links (compared to the time scales of the epidemic spreading). A simple mean field theory is presented for the selective adaptations which capture the qualitative and some of the quantitative features of the infection phase diagram.

  3. Epidemics spreading in interconnected complex networks

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Y. [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore); Institute of High Performance Computing, Agency for Science, Technology and Research (A-STAR), Singapore 138632 (Singapore); Xiao, G., E-mail: egxxiao@ntu.edu.sg [School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore 639798 (Singapore)

    2012-09-03

    We study epidemic spreading in two interconnected complex networks. It is found that in our model the epidemic threshold of the interconnected network is always lower than that in any of the two component networks. Detailed theoretical analysis is proposed which allows quick and accurate calculations of epidemic threshold and average outbreak/epidemic size. Theoretical analysis and simulation results show that, generally speaking, the epidemic size is not significantly affected by the inter-network correlation. In interdependent networks which can be viewed as a special case of interconnected networks, however, impacts of inter-network correlation on the epidemic threshold and outbreak size are more significant. -- Highlights: ► We study epidemic spreading in two interconnected complex networks. ► The epidemic threshold is lower than that in any of the two networks. And Interconnection correlation has impacts on threshold and average outbreak size. ► Detailed theoretical analysis is proposed which allows quick and accurate calculations of epidemic threshold and average outbreak/epidemic size. ► We demonstrated and proved that Interconnection correlation does not affect epidemic size significantly. ► In interdependent networks, impacts of inter-network correlation on the epidemic threshold and outbreak size are more significant.

  4. Modelling dengue epidemic spreading with human mobility

    Science.gov (United States)

    Barmak, D. H.; Dorso, C. O.; Otero, M.

    2016-04-01

    We explored the effect of human mobility on the spatio-temporal dynamics of Dengue with a stochastic model that takes into account the epidemiological dynamics of the infected mosquitoes and humans, with different mobility patterns of the human population. We observed that human mobility strongly affects the spread of infection by increasing the final size and by changing the morphology of the epidemic outbreaks. When the spreading of the disease is driven only by mosquito dispersal (flight), a main central focus expands diffusively. On the contrary, when human mobility is taken into account, multiple foci appear throughout the evolution of the outbreaks. These secondary foci generated throughout the outbreaks could be of little importance according to their mass or size compared with the largest main focus. However, the coalescence of these foci with the main one generates an effect, through which the latter develops a size greater than the one obtained in the case driven only by mosquito dispersal. This increase in growth rate due to human mobility and the coalescence of the foci are particularly relevant in temperate cities such as the city of Buenos Aires, since they give more possibilities to the outbreak to grow before the arrival of the low-temperature season. The findings of this work indicate that human mobility could be the main driving force in the dynamics of vector epidemics.

  5. The effect of glenosphere diameter in reverse shoulder arthroplasty on muscle force, joint load, and range of motion.

    Science.gov (United States)

    Langohr, G Daniel G; Giles, Joshua W; Athwal, George S; Johnson, James A

    2015-06-01

    Little is known about the effects of glenosphere diameter on shoulder joint loads. The purpose of this biomechanical study was to investigate the effects of glenosphere diameter on joint load, load angle, and total deltoid force required for active abduction and range of motion in internal/external rotation and abduction. A custom, instrumented reverse shoulder arthroplasty implant system capable of measuring joint load and varying glenosphere diameter (38 and 42 mm) and glenoid offset (neutral and lateral) was implanted in 6 cadaveric shoulders to provide at least 80% power for all variables. A shoulder motion simulator was used to produce active glenohumeral and scapulothoracic motion. All implant configurations were tested with active and passive motion with joint kinematics, loads, and moments recorded. At neutral and lateralized glenosphere positions, increasing diameter significantly increased joint load (+12 ± 21 N and +6 ± 9 N; P  .8). Passive internal rotation was reduced with increased diameter at both neutral and lateralized glenosphere positions (-6° ± 6° and -12° ± 6°; P  .05). At neutral glenosphere position, increasing diameter increased the maximum angles of both adduction (+1° ± 1°; P = .03) and abduction (+8° ± 9°; P < .05). Lateralization also increased abduction range of motion compared with neutral (P < .01). Although increasing glenosphere diameter significantly increased joint load and deltoid force, the clinical impact of these changes is presently unclear. Internal rotation, however, was reduced, which contradicts previous bone modeling studies, which we postulate is due to increased posterior capsular tension as it is forced to wrap around a larger 42 mm implant assembly. Copyright © 2015 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

  6. Effect of implantoplasty on fracture resistance and surface roughness of standard diameter dental implants.

    Science.gov (United States)

    Costa-Berenguer, Xavier; García-García, Marta; Sánchez-Torres, Alba; Sanz-Alonso, Mariano; Figueiredo, Rui; Valmaseda-Castellón, Eduard

    2018-01-01

    To assess the effect of implantoplasty on the fracture resistance, surface roughness, and macroscopic morphology of standard diameter (4.1 mm) external connection dental implants. An in vitro study was conducted in 20 screw-shaped titanium dental implants with an external connection. In 10 implants, the threads and surface were removed and polished with high-speed burs (implantoplasty), while the remaining 10 implants were used as controls. The final implant dimensions were recorded. The newly polished surface quality was assessed by scanning electron microscopy (SEM) and by 3D surface roughness analysis using a confocal laser microscope. Finally, all the implants were subjected to a mechanical pressure resistance test. A descriptive analysis of the data was made. Also, Student's t tests were employed to detect differences regarding the compression tests. Implantoplasty was carried out for a mean time of 10 min and 48 s (standard deviation (SD) of 1 min 22 s). Macroscopically, the resulting surface had a smooth appearance, although small titanium shavings and silicon debris were present. The final surface roughness (S a values 0.1 ± 0.02 μm) was significantly lower than that of the original (0.75 ± 0.08 μm S a ) (p = .005). There was minimal reduction in the implant's inner body diameter (0.19 ± 0.03 mm), and no statistically significant differences were found between the test and control implants regarding the maximum resistance force (896 vs 880 N, respectively). Implantoplasty, although technically demanding and time-consuming, does not seem to significantly alter fracture resistance of standard diameter external connection implants. A smooth surface with S a values below 0.1 μm can be obtained through the use of silicon polishers. A larger sample is required to confirm that implantoplasty does not significantly affect the maximum resistance force of standard diameter external connection implants. © 2017 John Wiley & Sons A/S. Published

  7. A fundamental look at fire spread in California chaparral

    Science.gov (United States)

    David R. Weise; Thomas Fletcher; Larry Baxter; Shankar Mahalingam; Xiangyang Zhou; Patrick Pagni; Rod Linn; Bret Butler

    2004-01-01

    The USDA Forest Service National Fire Plan funded a research program to study fire spread in live fuels of the southwestern United States. In the U.S. current operational fire spread models do not distinguish between live and dead fuels in a sophisticated manner because the study of live fuels has been limited. The program is experimentally examining fire spread at 3...

  8. The joint estimation of term structures and credit spreads

    NARCIS (Netherlands)

    Houweling, P.; Hoek, J.; Kleibergen, F.R.

    1999-01-01

    We present a new framework for the joint estimation of the default-free government term structure and corporate credit spread curves. By using a data set of liquid, German mark denominated bonds, we show that this yields more realistic spreads than traditionally obtained spread curves that result

  9. Forecasting oil price movements with crack spread futures

    International Nuclear Information System (INIS)

    Murat, Atilim; Tokat, Ekin

    2009-01-01

    In oil markets, the crack spread refers to the crude-product price relationship. Refiners are major participants in oil markets and they are primarily exposed to the crack spread. In other words, refiner activity is substantially driven by the objective of protecting the crack spread. Moreover, oil consumers are active participants in the oil hedging market and they are frequently exposed to the crack spread. From another perspective, hedge funds are heavily using crack spread to speculate in oil markets. Based on the high volume of crack spread futures trading in oil markets, the question we want to raise is whether the crack spread futures can be a good predictor of oil price movements. We investigated first whether there is a causal relationship between the crack spread futures and the spot oil markets in a vector error correction framework. We found the causal impact of crack spread futures on spot oil market both in the long- and the short-run after April 2003 where we detected a structural break in the model. To examine the forecasting performance, we use the random walk model (RWM) as a benchmark, and we also evaluate the forecasting power of crack spread futures against the crude oil futures. The results showed that (a) both the crack spread futures and the crude oil futures outperformed the RWM; and (b) the crack spread futures are almost as good as the crude oil futures in predicting the movements in spot oil markets. (author)

  10. Maximum gravitational redshift of white dwarfs

    International Nuclear Information System (INIS)

    Shapiro, S.L.; Teukolsky, S.A.

    1976-01-01

    The stability of uniformly rotating, cold white dwarfs is examined in the framework of the Parametrized Post-Newtonian (PPN) formalism of Will and Nordtvedt. The maximum central density and gravitational redshift of a white dwarf are determined as functions of five of the nine PPN parameters (γ, β, zeta 2 , zeta 3 , and zeta 4 ), the total angular momentum J, and the composition of the star. General relativity predicts that the maximum redshifts is 571 km s -1 for nonrotating carbon and helium dwarfs, but is lower for stars composed of heavier nuclei. Uniform rotation can increase the maximum redshift to 647 km s -1 for carbon stars (the neutronization limit) and to 893 km s -1 for helium stars (the uniform rotation limit). The redshift distribution of a larger sample of white dwarfs may help determine the composition of their cores

  11. Comparison between transcerebellar diameter with biparietal diameter of ultrasound for gestational age measurement in third trimester of pregnancy

    International Nuclear Information System (INIS)

    Naseem, F.; Fatima, N.; Yasmeen, S.; Saleem, S.

    2013-01-01

    To determine the frequency of correct assessment by transcerebeller diameter (TCD) versus biparietal diameter (BPD) for gestational age measurement at 36 weeks of pregnancy using first day of last menstrual period (LMP) for actual period of gestation. Study Design: Quasi experimental. Place and Duration of Study: Department of Obstetrics and Gynaecology, Bahawal Victoria Hospital, Bahawalpur from May to November 2010. Methodology: This study was performed on 228 patients at 36 weeks of pregnancy fulfilling the inclusion criteria. Ultrasound measurements of TCD and BPD was made and compared with LMP. Collected data was analyzed by SPSS version 10. Proportoin of correct diagnosis by each measurement was determined and compared using chi-square test with significance at p < 0.05. Results: Out of 228 patients, TCD was found to give correct assessment in 209 patients (91.7%; p = 0.001) corresponding to the gestational age by LMP i.e 36 weeks. BPD was found to give correct assessment corresponding to the gestational age by LMP in 176 patients (77.2%). Conclusion: Although both BPD and TCD are accurate biometric parameters at 36 weeks of gestation, transcerebellar diameter is more reliable method of gestational age determination in third trimester of pregnancy than biparietal diameter. TCD can be used as a tool to assist in the assessment of gestational age in third trimester. (author)

  12. Simulation of the WWER-440/213 maximum credible accident at the EhNITs stand

    International Nuclear Information System (INIS)

    Blinkov, V.N.; Melikhov, O.I.; Melikhov, V.I.; Davydov, M.V.; Sokolin, A.V.; Shchepetil'nikov, Eh.Yu.

    2000-01-01

    The calculations of thermohydraulic processes through the ATHLET code for determining optimal conditions for modeling the coolant leakage at the EhNITs stand by the maximum credible accident at the NPP with WWER-440/213 reactor are presented. The diameters of the nozzle at the stand, whereby the local criterion of coincidence with the data on the NPP (by the maximum flow) and integral criterion of coincidence (by the mass and energy of the coolant, effluent during 10 s) are determined in the process of parametric calculations [ru

  13. Maximum entropy analysis of EGRET data

    DEFF Research Database (Denmark)

    Pohl, M.; Strong, A.W.

    1997-01-01

    EGRET data are usually analysed on the basis of the Maximum-Likelihood method \\cite{ma96} in a search for point sources in excess to a model for the background radiation (e.g. \\cite{hu97}). This method depends strongly on the quality of the background model, and thus may have high systematic unce...... uncertainties in region of strong and uncertain background like the Galactic Center region. Here we show images of such regions obtained by the quantified Maximum-Entropy method. We also discuss a possible further use of MEM in the analysis of problematic regions of the sky....

  14. The Maximum Resource Bin Packing Problem

    DEFF Research Database (Denmark)

    Boyar, J.; Epstein, L.; Favrholdt, L.M.

    2006-01-01

    Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find...

  15. Topics in Bayesian statistics and maximum entropy

    International Nuclear Information System (INIS)

    Mutihac, R.; Cicuttin, A.; Cerdeira, A.; Stanciulescu, C.

    1998-12-01

    Notions of Bayesian decision theory and maximum entropy methods are reviewed with particular emphasis on probabilistic inference and Bayesian modeling. The axiomatic approach is considered as the best justification of Bayesian analysis and maximum entropy principle applied in natural sciences. Particular emphasis is put on solving the inverse problem in digital image restoration and Bayesian modeling of neural networks. Further topics addressed briefly include language modeling, neutron scattering, multiuser detection and channel equalization in digital communications, genetic information, and Bayesian court decision-making. (author)

  16. Density estimation by maximum quantum entropy

    International Nuclear Information System (INIS)

    Silver, R.N.; Wallstrom, T.; Martz, H.F.

    1993-01-01

    A new Bayesian method for non-parametric density estimation is proposed, based on a mathematical analogy to quantum statistical physics. The mathematical procedure is related to maximum entropy methods for inverse problems and image reconstruction. The information divergence enforces global smoothing toward default models, convexity, positivity, extensivity and normalization. The novel feature is the replacement of classical entropy by quantum entropy, so that local smoothing is enforced by constraints on differential operators. The linear response of the estimate is proportional to the covariance. The hyperparameters are estimated by type-II maximum likelihood (evidence). The method is demonstrated on textbook data sets

  17. Two-phase flow structure in large diameter pipes

    International Nuclear Information System (INIS)

    Smith, T.R.; Schlegel, J.P.; Hibiki, T.; Ishii, M.

    2012-01-01

    Highlights: ► Local profiles of various quantities measured in large diameter pipe. ► Database for interfacial area in large pipes extended to churn-turbulent flow. ► Flow regime map confirms previous models for flow regime transitions. ► Data will be useful in developing interfacial area transport models for large pipes. - Abstract: Flow in large pipes is important in a wide variety of applications. In the nuclear industry in particular, understanding of flow in large diameter pipes is essential in predicting the behavior of reactor systems. This is especially true of natural circulation Boiling Water Reactor (BWR) designs, where a large-diameter chimney above the core provides the gravity head to drive circulation of the coolant through the reactor. The behavior of such reactors during transients and during normal operation will be predicted using advanced thermal–hydraulics analysis codes utilizing the two-fluid model. Essential to accurate two-fluid model calculations is reliable and accurate computation of the interfacial transfer terms. These interfacial transfer terms can be expressed as the product of one term describing the potential driving the transfer and a second term describing the available surface area for transfer, or interfacial area concentration. Currently, the interfacial area is predicted using flow regime dependent empirical correlations; however the interfacial area concentration is best computed through the use of the one-dimensional interfacial area transport equation (IATE). To facilitate the development of IATE source and sink term models in large-diameter pipes a fundamental understanding of the structure of the two-phase flow is essential. This understanding is improved through measurement of the local void fraction, interfacial area concentration and gas velocity profiles in pipes with diameters of 0.102 m and 0.152 m under a wide variety of flow conditions. Additionally, flow regime identification has been performed to

  18. Normal cardiac diameters in cine-MRI of the heart

    International Nuclear Information System (INIS)

    Hergan, K.; Schuster, A.; Mair, M.; Burger, R.; Toepker, M.

    2004-01-01

    Purpose: To measure the normal diameters of cardiac cavities in standard cardiac views using cine MRI. Materials and Methods: Fifty-six volunteers were examined (27 male, 29 female) on a 1.5 T MR unit with ECG-triggered single shot free precision (SSFP) cine MR sequences and parallel image acquisition. Standardized echocardiographic planes were used to depict the heart of all volunteers (short axis, 4-chamber view, left and right 2-chamber views). The different diameters of the cardiac cavities were measured using a fixed protocol. Results: For the estimation of ventricular dilatation, the important female/male cross diameters of the left ventricle are 45.2±3.4/51.6±4.6 mm diastolic and 30.5±3.5/33.8±3.6 mm systolic, and of the right ventricle 30.7±3.8/37.1±5.9 mm diastolic and 22.3±3.8/28.1±4.4 mm systolic. For the determination of a left ventricular hypertrophy, relevant septal wall thickness measured in the short axis of the left ventricle of female/male volunteers are 8.0±1.0/9.9±1.2 mm diastolic and 10.9±1.4/13.6±1.9 mm systolic. The measured normal values of male volunteers were generally higher than those of female volunteers. The thickness of the ventricular septum correlated well when measured in the short axis and 4-chamber view. When measured in the 4-chamber view, the longitudinal diameter of the ventricles had a higher value in diastole and a lower value in systole, compared to the 2-chamber views of the right and left cardiac cavities. The atrial longitudinal diameters were higher in the 4-chamber view compared to the 2-chamber views, without any difference in systole or diastole. Conclusion: Diameters of cardiac cavities are easily and quickly measured. Using the tables with the normal values published here, it is simple to estimate an abnormal size of the heart. (orig.)

  19. Information spread in networks: Games, optimal control, and stabilization

    Science.gov (United States)

    Khanafer, Ali

    This thesis focuses on designing efficient mechanisms for controlling information spread in networks. We consider two models for information spread. The first one is the well-known distributed averaging dynamics. The second model is a nonlinear one that describes virus spread in computer and biological networks. We seek to design optimal, robust, and stabilizing controllers under practical constraints. For distributed averaging networks, we study the interaction between a network designer and an adversary. We consider two types of attacks on the network. In Attack-I, the adversary strategically disconnects a set of links to prevent the nodes from reaching consensus. Meanwhile, the network designer assists the nodes in reaching consensus by changing the weights of a limited number of links in the network. We formulate two problems to describe this competition where the order in which the players act is reversed in the two problems. Although the canonical equations provided by the Pontryagin's Maximum Principle (MP) seem to be intractable, we provide an alternative characterization for the optimal strategies that makes connection to potential theory. Further, we provide a sufficient condition for the existence of a saddle-point equilibrium (SPE) for the underlying zero-sum game. In Attack-II, the designer and the adversary are both capable of altering the measurements of all nodes in the network by injecting global signals. We impose two constraints on both players: a power constraint and an energy constraint. We assume that the available energy to each player is not sufficient to operate at maximum power throughout the horizon of the game. We show the existence of an SPE and derive the optimal strategies in closed form for this attack scenario. As an alternative to the "network designer vs. adversary" framework, we investigate the possibility of stabilizing unknown network diffusion processes using a distributed mechanism, where the uncertainty is due to an attack

  20. Hydroclimatological And Anthropogenic Drivers For Cholera Spreading

    Science.gov (United States)

    Righetto, Lorenzo; Bertuzzo, Enrico; Mari, Lorenzo; Casagrandi, Renato; Gatto, Marino; Rinaldo, Andrea

    2010-05-01

    The nature of waterborne diseases, among which cholera has a prominent importance, calls for a better understanding of the link between epidemic spreading, water and climate. To this end, we have developed a framework which involves a network-based description of a river system, connected with local communities which act as nodes of the network. This has allowed us to produce consistent simulations of real case studies. More recent investigations comprise the evaluation of the spreading velocity of an epidemic wave by means of a reaction-diffusion modeling approach. In particular, we have found that both transport processes and epidemiological quantities, such as the basic reproduction number, have a crucial effect in controlling the spreading of the epidemics. We first developed a description of bacterial movement along the network driven by advection and diffusion; afterward, we have included the movement of human populations. This latter model allowed us to establish the conditions that can trigger epidemic waves that start from the coastal region, where bacteria are autochthonous, and travel inland. In particular, our findings suggest that even relatively low values of human diffusion can have the epidemic propagate upstream. The interaction between climate, hydrology and epidemic events is still much debated, since no clear correlation between climatologic and epidemiological phenomena has emerged so far. However, a spatial assessment of hydrological and epidemiological mechanisms could be crucial to understand the evolution of cholera outbreaks. In particular, a hotly debated topic is the understanding of the mechanisms that can generate patterns of cholera incidence that exhibit an intra-annual double peak, as frequently observed in endemic region such as Bangladesh. One of the possible explanations proposed in the literature is that spring droughts cause bacteria concentration in water to rise dramatically, triggering the first peak. On the other hand

  1. Operator Spreading in Random Unitary Circuits

    Science.gov (United States)

    Nahum, Adam; Vijay, Sagar; Haah, Jeongwan

    2018-04-01

    Random quantum circuits yield minimally structured models for chaotic quantum dynamics, which are able to capture, for example, universal properties of entanglement growth. We provide exact results and coarse-grained models for the spreading of operators by quantum circuits made of Haar-random unitaries. We study both 1 +1 D and higher dimensions and argue that the coarse-grained pictures carry over to operator spreading in generic many-body systems. In 1 +1 D , we demonstrate that the out-of-time-order correlator (OTOC) satisfies a biased diffusion equation, which gives exact results for the spatial profile of the OTOC and determines the butterfly speed vB. We find that in 1 +1 D , the "front" of the OTOC broadens diffusively, with a width scaling in time as t1 /2. We address fluctuations in the OTOC between different realizations of the random circuit, arguing that they are negligible in comparison to the broadening of the front within a realization. Turning to higher dimensions, we show that the averaged OTOC can be understood exactly via a remarkable correspondence with a purely classical droplet growth problem. This implies that the width of the front of the averaged OTOC scales as t1 /3 in 2 +1 D and as t0.240 in 3 +1 D (exponents of the Kardar-Parisi-Zhang universality class). We support our analytic argument with simulations in 2 +1 D . We point out that, in two or higher spatial dimensions, the shape of the spreading operator at late times is affected by underlying lattice symmetries and, in general, is not spherical. However, when full spatial rotational symmetry is present in 2 +1 D , our mapping implies an exact asymptotic form for the OTOC, in terms of the Tracy-Widom distribution. For an alternative perspective on the OTOC in 1 +1 D , we map it to the partition function of an Ising-like statistical mechanics model. As a result of special structure arising from unitarity, this partition function reduces to a random walk calculation which can be

  2. Flame Spread and Group-Combustion Excitation in Randomly Distributed Droplet Clouds with Low-Volatility Fuel near the Excitation Limit: a Percolation Approach Based on Flame-Spread Characteristics in Microgravity

    Science.gov (United States)

    Mikami, Masato; Saputro, Herman; Seo, Takehiko; Oyagi, Hiroshi

    2018-03-01

    Stable operation of liquid-fueled combustors requires the group combustion of fuel spray. Our study employs a percolation approach to describe unsteady group-combustion excitation based on findings obtained from microgravity experiments on the flame spread of fuel droplets. We focus on droplet clouds distributed randomly in three-dimensional square lattices with a low-volatility fuel, such as n-decane in room-temperature air, where the pre-vaporization effect is negligible. We also focus on the flame spread in dilute droplet clouds near the group-combustion-excitation limit, where the droplet interactive effect is assumed negligible. The results show that the occurrence probability of group combustion sharply decreases with the increase in mean droplet spacing around a specific value, which is termed the critical mean droplet spacing. If the lattice size is at smallest about ten times as large as the flame-spread limit distance, the flame-spread characteristics are similar to those over an infinitely large cluster. The number density of unburned droplets remaining after completion of burning attained maximum around the critical mean droplet spacing. Therefore, the critical mean droplet spacing is a good index for stable combustion and unburned hydrocarbon. In the critical condition, the flame spreads through complicated paths, and thus the characteristic time scale of flame spread over droplet clouds has a very large value. The overall flame-spread rate of randomly distributed droplet clouds is almost the same as the flame-spread rate of a linear droplet array except over the flame-spread limit.

  3. Critical Assessment of the Surface Tension determined by the Maximum Pressure Bubble Method

    OpenAIRE

    Benedetto, Franco Emmanuel; Zolotucho, Hector; Prado, Miguel Oscar

    2015-01-01

    The main factors that influence the value of surface tension of a liquid measured with the Maximum Pressure Bubble Method are critically evaluated. We present experimental results showing the effect of capillary diameter, capillary depth, bubble spheroidicity and liquid density at room temperature. We show that the decrease of bubble spheroidicity due to increase of capillary immersion depth is not sufficient to explain the deviations found in the measured surface tension values. Thus, we pro...

  4. Resource Allocation with Adaptive Spread Spectrum OFDM Using 2D Spreading for Power Line Communications

    Directory of Open Access Journals (Sweden)

    Baudais Jean-Yves

    2007-01-01

    Full Text Available Bit-loading techniques based on orthogonal frequency division mutiplexing (OFDM are frequently used over wireline channels. In the power line context, channel state information can reasonably be obtained at both transmitter and receiver sides, and adaptive loading can advantageously be carried out. In this paper, we propose to apply loading principles to an spread spectrum OFDM (SS-OFDM waveform which is a multicarrier system using 2D spreading in the time and frequency domains. The presented algorithm handles the subcarriers, spreading codes, bits and energies assignment in order to maximize the data rate and the range of the communication system. The optimization is realized at a target symbol error rate and under spectral mask constraint as usually imposed. The analytical study shows that the merging principle realized by the spreading code improves the rate and the range of the discrete multitone (DMT system in single and multiuser contexts. Simulations have been run over measured power line communication (PLC channel responses and highlight that the proposed system is all the more interesting than the received signal-to-noise ratio (SNR is low.

  5. Resource Allocation with Adaptive Spread Spectrum OFDM Using 2D Spreading for Power Line Communications

    Science.gov (United States)

    Baudais, Jean-Yves; Crussière, Matthieu

    2007-12-01

    Bit-loading techniques based on orthogonal frequency division mutiplexing (OFDM) are frequently used over wireline channels. In the power line context, channel state information can reasonably be obtained at both transmitter and receiver sides, and adaptive loading can advantageously be carried out. In this paper, we propose to apply loading principles to an spread spectrum OFDM (SS-OFDM) waveform which is a multicarrier system using 2D spreading in the time and frequency domains. The presented algorithm handles the subcarriers, spreading codes, bits and energies assignment in order to maximize the data rate and the range of the communication system. The optimization is realized at a target symbol error rate and under spectral mask constraint as usually imposed. The analytical study shows that the merging principle realized by the spreading code improves the rate and the range of the discrete multitone (DMT) system in single and multiuser contexts. Simulations have been run over measured power line communication (PLC) channel responses and highlight that the proposed system is all the more interesting than the received signal-to-noise ratio (SNR) is low.

  6. Dielectric fluid directional spreading under the action of corona discharge

    Science.gov (United States)

    Zhou, Shangru; Liu, Jie; Hu, Qun; Jiang, Teng; Yang, Jinchu; Liu, Sheng; Zheng, Huai

    2018-01-01

    Liquid spreading is a very common nature phenomenon and of significant importance for a broad range of applications. In this study, a dielectric fluid directional spreading phenomenon is presented. Under the action of corona discharge, a dielectric fluid, here a typical silicone directionally spreads along conductive patterns on conductive/nonconductive substrates. Directional spreading behaviors of silicone were experimentally observed on different conductive patterns in detail. Spreading speeds were analyzed at different driving voltages, which induced the corona discharge. The presented phenomenon may be useful to inspire several techniques of manipulating liquid transportation and fabricating micropatterns.

  7. Angular diameters of Magellanic Cloud plantary nebulae. I. Speckle interferometry

    International Nuclear Information System (INIS)

    Wood, P.R.; Bessell, M.S.; Dopita, M.A.

    1986-01-01

    Speckle interferometric angular diameters of Magellanic Cloud planetary nebulae are presented. The mass of ionized gas in each nebula has been derived from the angular diameter and published H-beta line fluxes; the derives masses range from less than 0.006 to more than 0.19 solar mass. The planetary nebulae observed were the brightest in the Magellanic Clouds; consequently, they are all relatively small, young, bright, and dense. They are almost certainly only partially ionized, so that the masses derived for the ionized parts of the nebula are lower limits to the total nebula mass. The properties of the Magellanic Cloud nebulae are compared with those of planetary nebulae at the galactic center. 27 references

  8. Problems of cleaning the large diameter sections of deep wells

    Energy Technology Data Exchange (ETDEWEB)

    Patsch, F; Gilicz, B

    1966-01-01

    In drilling deep wells, great importance is being given to the problem of cutting removal from the hole bottom of sections drilled by large diameter bits. The length of borehole sections drilled by 12-1/4-in. and larger bits has been more than doubled in Hungary in the course of the past 4 years. When the drilling fluid jet is struck against the borehole bottom, pressure waves are brought about which take on a crossed flow pattern and result in a retardation of cleaning of the well bottom, particularly in the case of larger bottom surfaces. In large diameter boreholes, the cleaning efficiency is being achieved by full utilization of the pump power and increased pump delivery. Friction losses in drill pipes are being reduced by using 6-in. XH pipes.

  9. Improved Design Basis for Laterally Loaded Large Diameter Pile

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    of the diameter, depth and soil strength, and increase of each these will give an increase in stiffness. • Cyclic response of a lateral loaded pile is depended on the characteristics of the cyclic load. Behaviour of a monopile is a classic soil-structure interaction problem depending on the pile stiffness....... The target is to improve the use of monopiles as preferred support structure beyond the current limit at a water depth of 30 m. Design of foundations for wind turbines has a large focus on the stiffness of the combined structure, turbine-tower-foundation, which has an influence on the environmental loads...... initial response and a higher ultimate capacity. The initial stiffness of the soil-structure interaction measured in the centrifuge tests, equivalent to initial stiffness of p-y curves, shows a dependency of depth and diameter. Control issues in relation to cyclic tests have resulted in tests...

  10. Status of the variable diameter centerbody inlet program

    Science.gov (United States)

    Saunders, John D.; Linne, A. A.

    1992-01-01

    The Variable Diameter Centerbody (VDC) inlet is an ongoing research program at LeRC. The VDC inlet is a mixed compression, axisymmetric inlet that has potential application on the next generation supersonic transport. This inlet was identified as one of the most promising axisymmetric concepts for supersonic cruise aircraft during the SCAR program in the late 1970's. Some of its features include high recovery, low bleed, good angle-of-attack tolerance, and excellent engine airflow matching. These features were demonstrated at LeRC in the past by the design and testing of fixed hardware models. A current test program in the LeRC 10' x 10' Supersonic Wind Tunnel (SWT) will attempt to duplicate these features on model hardware that actually incorporates a flight-like variable diameter centerbody mechanism.

  11. Modeling Epidemics Spreading on Social Contact Networks.

    Science.gov (United States)

    Zhang, Zhaoyang; Wang, Honggang; Wang, Chonggang; Fang, Hua

    2015-09-01

    Social contact networks and the way people interact with each other are the key factors that impact on epidemics spreading. However, it is challenging to model the behavior of epidemics based on social contact networks due to their high dynamics. Traditional models such as susceptible-infected-recovered (SIR) model ignore the crowding or protection effect and thus has some unrealistic assumption. In this paper, we consider the crowding or protection effect and develop a novel model called improved SIR model. Then, we use both deterministic and stochastic models to characterize the dynamics of epidemics on social contact networks. The results from both simulations and real data set conclude that the epidemics are more likely to outbreak on social contact networks with higher average degree. We also present some potential immunization strategies, such as random set immunization, dominating set immunization, and high degree set immunization to further prove the conclusion.

  12. Spread of epidemic disease on networks

    Science.gov (United States)

    Newman, M. E.

    2002-07-01

    The study of social networks, and in particular the spread of disease on networks, has attracted considerable recent attention in the physics community. In this paper, we show that a large class of standard epidemiological models, the so-called susceptible/infective/removed (SIR) models can be solved exactly on a wide variety of networks. In addition to the standard but unrealistic case of fixed infectiveness time and fixed and uncorrelated probability of transmission between all pairs of individuals, we solve cases in which times and probabilities are nonuniform and correlated. We also consider one simple case of an epidemic in a structured population, that of a sexually transmitted disease in a population divided into men and women. We confirm the correctness of our exact solutions with numerical simulations of SIR epidemics on networks.

  13. Quarantine generated phase transition in epidemic spreading

    Science.gov (United States)

    Dicksion, Mark; Lagorio, Cecilia; Vazquez, F.; Braunstein, L.; Macri, P. A.; Migueles, M. V.; Havlin, S.; Stanley, H. E.

    2011-03-01

    We study the critical effect of quarantine on the propagation of epidemics on an adaptive network of social contacts. For this purpose, we analyze the susceptible-infected-recovered (SIR) model in the presence of quarantine, where susceptible individuals protect themselves by disconnecting their links to infected neighbors with probability w, and reconnecting them to other susceptible individuals chosen at random. Starting from a single infected individual, we show by an analytical approach and simulations that there is a phase transition at a critical rewiring (quarantine) threshold wc separating a phase (w =wc) where the disease does not spread out. We find that in our model the topology of the network strongly affects the size of the propagation, and that wc increases with the mean degree and heterogeneity of the network. We also find that wc is reduced if we perform a preferential rewiring, in which the rewiring probability is proportional to the degree of infected nodes.

  14. Abnormal cascading failure spreading on complex networks

    International Nuclear Information System (INIS)

    Wang, Jianwei; Sun, Enhui; Xu, Bo; Li, Peng; Ni, Chengzhang

    2016-01-01

    Applying the mechanism of the preferential selection of the flow destination, we develop a new method to quantify the initial load on an edge, of which the flow is transported along the path with the shortest edge weight between two nodes. Considering the node weight, we propose a cascading model on the edge and investigate cascading dynamics induced by the removal of the edge with the largest load. We perform simulated attacks on four types of constructed networks and two actual networks and observe an interesting and counterintuitive phenomenon of the cascading spreading, i.e., gradually improving the capacity of nodes does not lead to the monotonous increase in the robustness of these networks against cascading failures. The non monotonous behavior of cascading dynamics is well explained by the analysis on a simple graph. We additionally study the effect of the parameter of the node weight on cascading dynamics and evaluate the network robustness by a new metric.

  15. Intensity-dependent point spread image processing

    International Nuclear Information System (INIS)

    Cornsweet, T.N.; Yellott, J.I.

    1984-01-01

    There is ample anatomical, physiological and psychophysical evidence that the mammilian retina contains networks that mediate interactions among neighboring receptors, resulting in intersecting transformations between input images and their corresponding neural output patterns. The almost universally accepted view is that the principal form of interaction involves lateral inhibition, resulting in an output pattern that is the convolution of the input with a ''Mexican hat'' or difference-of-Gaussians spread function, having a positive center and a negative surround. A closely related process is widely applied in digital image processing, and in photography as ''unsharp masking''. The authors show that a simple and fundamentally different process, involving no inhibitory or subtractive terms can also account for the physiological and psychophysical findings that have been attributed to lateral inhibition. This process also results in a number of fundamental effects that occur in mammalian vision and that would be of considerable significance in robotic vision, but which cannot be explained by lateral inhibitory interaction

  16. Spread of acid rain over India

    Science.gov (United States)

    Khemani, L. T.; Momin, G. A.; Rao, P. S. Prakasa; Safai, P. D.; Singh, G.; Kapoor, R. K.

    Rain water and aerosol samples were collected at a few locations representative of urban and non-urban regions in India. Also, rain water samples were collected in and around a coal-fired power plant. All the rain water and aerosol samples were analyzed for major chemical components along with pH. The rain water at all the places of measurement, except near the industrial sources, has been found to be alkaline and was characterized by the presence of excess cations, particularly by Ca 2+. The acid rain near the industrial sources was associated with excess anions, especially SO 42-. The atmospheric aerosols at all the places of measurement were found rich with basic components, suggesting that the alkaline soil dust and fly ash are responsible at present for preventing the spread of acid rain in India.

  17. Emergence and spreading potential of Zika virus

    Directory of Open Access Journals (Sweden)

    Alvaro Fajardo

    2016-10-01

    Full Text Available Zika virus (ZIKV is an arthropod-borne Flavivirus (family Flaviviridae closely related to dengue, yellow fever and West Nile viruses. ZIKV remained neglected, confined to enzootic transmission cycles in Africa and Asia, until the first significant outbreak was reported in Micronesia in 2007. Subsequent epidemics of growing incidence occurred in French Polynesia and other South Pacific Islands, and recently, in the Americas. The latter and currently ongoing outbreak of unprecedented incidence revealed the association of ZIKV infection with the occurrence of severe congenital malformations and neurological diseases, leading to a widespread concern about its potential to pose a global public health threat. Serological and molecular data suggest that the genetic and geographic diversification of ZIKV may be greatly underestimated. Here we discuss several ecological and epidemiological aspects, together with the evolutionary processes that may have driven the emergence and abrupt spread of ZIKV in the Americas.

  18. Avian Influenza spread and transmission dynamics

    Science.gov (United States)

    Bourouiba, Lydia; Gourley, Stephen A.; Liu, Rongsong; Takekawa, John Y.; Wu, Jianhong; Chen, Dongmei; Moulin, Bernard; Wu, Jianhong

    2015-01-01

    The spread of highly pathogenic avian influenza (HPAI) viruses of type A of subtype H5N1 has been a serious threat to global public health. Understanding the roles of various (migratory, wild, poultry) bird species in the transmission of these viruses is critical for designing and implementing effective control and intervention measures. Developing appropriate models and mathematical techniques to understand these roles and to evaluate the effectiveness of mitigation strategies have been a challenge. Recent development of the global health surveillance (especially satellite tracking and GIS techniques) and the mathematical theory of dynamical systems combined have gradually shown the promise of some cutting-edge methodologies and techniques in mathematical biology to meet this challenge.

  19. A versatile Czochralski crystal growth system with automatic diameter control

    Science.gov (United States)

    Aggarwal, M. D.; Metzl, R.; Wang, W. S.; Choi, J.

    1995-07-01

    A versatile Czochralski crystal pulling system with automatic diameter control for the growth of nonlinear optical oxide crystals is discussed. Pure and doped bulk single crystals of bismuth silicon oxide (Bi12SiO20) have been successfully grown using this system. The system consists of a regular Czochralski type pulling system with provision for continuous weighing of the growing crystal to provide feedback for power control.

  20. 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.

  1. Developing high coercivity in large diameter cobalt nanowire arrays

    Science.gov (United States)

    Montazer, A. H.; Ramazani, A.; Almasi Kashi, M.; Zavašnik, J.

    2016-11-01

    Regardless of the synthetic method, developing high magnetic coercivity in ferromagnetic nanowires (NWs) with large diameters has been a challenge over the past two decades. Here, we report on the synthesis of highly coercive cobalt NW arrays with diameters of 65 and 80 nm, which are embedded in porous anodic alumina templates with high-aspect-ratio pores. Using a modified electrochemical deposition method enabled us to reach room temperature coercivity and remanent ratio up to 3000 Oe and 0.70, respectively, for highly crystalline as-synthesized hcp cobalt NW arrays with a length of 8 μm. The first-order reversal curve (FORC) analysis showed the presence of both soft and hard magnetic phases along the length of the resulting NWs. To develop higher coercive fields, the length of the NWs was then gradually reduced in order from bottom to top, thereby reaching NW sections governed by the hard phase. Consequently, this resulted in record high coercivities of 4200 and 3850 Oe at NW diameters of 65 and 80 nm, respectively. In this case, the FORC diagrams confirmed a significant reduction in interactions between the magnetic phases of the remaining sections of NWs. At this stage, x-ray diffraction (XRD) and dark-field transmission electron microscopy analyses indicated the formation of highly crystalline bamboo-like sections along the [0 0 2] direction during a progressive pulse-controlled electrochemical growth of NW arrays under optimized parameters. Our results both provide new insights into the growth process, crystalline characteristics and magnetic phases along the length of large diameter NW arrays and, furthermore, develop the performance of pure 3d transition magnetic NWs.

  2. 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.

  3. A study of the heated length to diameter effects

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Ho; Baek, Won Pil; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1997-12-31

    An analytical and experimental investigation has been performed on the heated length-to-diameter effect on critical heat flux exit conditions. A L/D correction factor is developed by applying artificial neural network and conventional regression techniques to the KAIST CHF data base. In addition, experiment is being performed to validate the developed L/D correction factor with independent data. Assessment shows that the developed correction factor is promising for practical applications. 6 refs., 8 figs. (Author)

  4. Conditioning a segmented stem profile model for two diameter measurements

    Science.gov (United States)

    Raymond L. Czaplewski; Joe P. Mcclure

    1988-01-01

    The stem profile model of Max and Burkhart (1976) is conditioned for dbh and a second upper stem measurement. This model was applied to a loblolly pine data set using diameter outside bark at 5.3m (i.e., height of 17.3 foot Girard form class) as the second upper stem measurement, and then compared to the original, unconditioned model. Variance of residuals was reduced...

  5. Relationships between stem diameter at breast height (DBH), tree ...

    African Journals Online (AJOL)

    buba

    amount of light that the tree intercepts for photosynthesis. The tree stem size has its ... the amount of solar radiation intercepted by a tree. (Tanka, 2006). .... 7. Stem Diameter. C ro w n le n g th. Figure 2. Graph of the relationship between stem dbh vs. crown crown length. 0.7. 0.6. 0.5. 0.4. 0.3. 15. 14. 13. 12. 11. 10. 9. 8. 7. 6. 5.

  6. A study of the heated length to diameter effects

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Ho; Baek, Won Pil; Chang, Soon Heung [Korea Advanced Institute of Science and Technology, Taejon (Korea, Republic of)

    1998-12-31

    An analytical and experimental investigation has been performed on the heated length-to-diameter effect on critical heat flux exit conditions. A L/D correction factor is developed by applying artificial neural network and conventional regression techniques to the KAIST CHF data base. In addition, experiment is being performed to validate the developed L/D correction factor with independent data. Assessment shows that the developed correction factor is promising for practical applications. 6 refs., 8 figs. (Author)

  7. Visual function and retinal vessel diameters during hyperthermia in man

    DEFF Research Database (Denmark)

    Jensen, Bettina Hagström; Bram, Thue; Kappelgaard, Per

    2017-01-01

    .01), a 10.6-mmHg mean reduction in diastolic blood pressure (p vein...... laser ophthalmoscopy was used to measure retinal trunk vessel diameters. Assessment was made at baseline, during hyperthermia and after cooling. RESULTS: The induction of a mean increase in core body temperature of 1.02°C was associated with a 7.15-mmHg mean reduction in systolic blood pressure (p

  8. Nonsymmetric entropy and maximum nonsymmetric entropy principle

    International Nuclear Information System (INIS)

    Liu Chengshi

    2009-01-01

    Under the frame of a statistical model, the concept of nonsymmetric entropy which generalizes the concepts of Boltzmann's entropy and Shannon's entropy, is defined. Maximum nonsymmetric entropy principle is proved. Some important distribution laws such as power law, can be derived from this principle naturally. Especially, nonsymmetric entropy is more convenient than other entropy such as Tsallis's entropy in deriving power laws.

  9. Maximum speed of dewetting on a fiber

    NARCIS (Netherlands)

    Chan, Tak Shing; Gueudre, Thomas; Snoeijer, Jacobus Hendrikus

    2011-01-01

    A solid object can be coated by a nonwetting liquid since a receding contact line cannot exceed a critical speed. We theoretically investigate this forced wetting transition for axisymmetric menisci on fibers of varying radii. First, we use a matched asymptotic expansion and derive the maximum speed

  10. Maximum potential preventive effect of hip protectors

    NARCIS (Netherlands)

    van Schoor, N.M.; Smit, J.H.; Bouter, L.M.; Veenings, B.; Asma, G.B.; Lips, P.T.A.M.

    2007-01-01

    OBJECTIVES: To estimate the maximum potential preventive effect of hip protectors in older persons living in the community or homes for the elderly. DESIGN: Observational cohort study. SETTING: Emergency departments in the Netherlands. PARTICIPANTS: Hip fracture patients aged 70 and older who

  11. Maximum gain of Yagi-Uda arrays

    DEFF Research Database (Denmark)

    Bojsen, J.H.; Schjær-Jacobsen, Hans; Nilsson, E.

    1971-01-01

    Numerical optimisation techniques have been used to find the maximum gain of some specific parasitic arrays. The gain of an array of infinitely thin, equispaced dipoles loaded with arbitrary reactances has been optimised. The results show that standard travelling-wave design methods are not optimum....... Yagi–Uda arrays with equal and unequal spacing have also been optimised with experimental verification....

  12. correlation between maximum dry density and cohesion

    African Journals Online (AJOL)

    HOD

    represents maximum dry density, signifies plastic limit and is liquid limit. Researchers [6, 7] estimate compaction parameters. Aside from the correlation existing between compaction parameters and other physical quantities there are some other correlations that have been investigated by other researchers. The well-known.

  13. Weak scale from the maximum entropy principle

    Science.gov (United States)

    Hamada, Yuta; Kawai, Hikaru; Kawana, Kiyoharu

    2015-03-01

    The theory of the multiverse and wormholes suggests that the parameters of the Standard Model (SM) are fixed in such a way that the radiation of the S3 universe at the final stage S_rad becomes maximum, which we call the maximum entropy principle. Although it is difficult to confirm this principle generally, for a few parameters of the SM, we can check whether S_rad actually becomes maximum at the observed values. In this paper, we regard S_rad at the final stage as a function of the weak scale (the Higgs expectation value) vh, and show that it becomes maximum around vh = {{O}} (300 GeV) when the dimensionless couplings in the SM, i.e., the Higgs self-coupling, the gauge couplings, and the Yukawa couplings are fixed. Roughly speaking, we find that the weak scale is given by vh ˜ T_{BBN}2 / (M_{pl}ye5), where ye is the Yukawa coupling of electron, T_BBN is the temperature at which the Big Bang nucleosynthesis starts, and M_pl is the Planck mass.

  14. The maximum-entropy method in superspace

    Czech Academy of Sciences Publication Activity Database

    van Smaalen, S.; Palatinus, Lukáš; Schneider, M.

    2003-01-01

    Roč. 59, - (2003), s. 459-469 ISSN 0108-7673 Grant - others:DFG(DE) XX Institutional research plan: CEZ:AV0Z1010914 Keywords : maximum-entropy method, * aperiodic crystals * electron density Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.558, year: 2003

  15. Achieving maximum sustainable yield in mixed fisheries

    NARCIS (Netherlands)

    Ulrich, Clara; Vermard, Youen; Dolder, Paul J.; Brunel, Thomas; Jardim, Ernesto; Holmes, Steven J.; Kempf, Alexander; Mortensen, Lars O.; Poos, Jan Jaap; Rindorf, Anna

    2017-01-01

    Achieving single species maximum sustainable yield (MSY) in complex and dynamic fisheries targeting multiple species (mixed fisheries) is challenging because achieving the objective for one species may mean missing the objective for another. The North Sea mixed fisheries are a representative example

  16. 5 CFR 534.203 - Maximum stipends.

    Science.gov (United States)

    2010-01-01

    ... maximum stipend established under this section. (e) A trainee at a non-Federal hospital, clinic, or medical or dental laboratory who is assigned to a Federal hospital, clinic, or medical or dental... Administrative Personnel OFFICE OF PERSONNEL MANAGEMENT CIVIL SERVICE REGULATIONS PAY UNDER OTHER SYSTEMS Student...

  17. Minimal length, Friedmann equations and maximum density

    Energy Technology Data Exchange (ETDEWEB)

    Awad, Adel [Center for Theoretical Physics, British University of Egypt,Sherouk City 11837, P.O. Box 43 (Egypt); Department of Physics, Faculty of Science, Ain Shams University,Cairo, 11566 (Egypt); Ali, Ahmed Farag [Centre for Fundamental Physics, Zewail City of Science and Technology,Sheikh Zayed, 12588, Giza (Egypt); Department of Physics, Faculty of Science, Benha University,Benha, 13518 (Egypt)

    2014-06-16

    Inspired by Jacobson’s thermodynamic approach, Cai et al. have shown the emergence of Friedmann equations from the first law of thermodynamics. We extend Akbar-Cai derivation http://dx.doi.org/10.1103/PhysRevD.75.084003 of Friedmann equations to accommodate a general entropy-area law. Studying the resulted Friedmann equations using a specific entropy-area law, which is motivated by the generalized uncertainty principle (GUP), reveals the existence of a maximum energy density closed to Planck density. Allowing for a general continuous pressure p(ρ,a) leads to bounded curvature invariants and a general nonsingular evolution. In this case, the maximum energy density is reached in a finite time and there is no cosmological evolution beyond this point which leaves the big bang singularity inaccessible from a spacetime prospective. The existence of maximum energy density and a general nonsingular evolution is independent of the equation of state and the spacial curvature k. As an example we study the evolution of the equation of state p=ωρ through its phase-space diagram to show the existence of a maximum energy which is reachable in a finite time.

  18. Quantifier spreading: children misled by ostensive cues

    Directory of Open Access Journals (Sweden)

    Katalin É. Kiss

    2017-04-01

    Full Text Available This paper calls attention to a methodological problem of acquisition experiments. It shows that the economy of the stimulus employed in child language experiments may lend an increased ostensive effect to the message communicated to the child. Thus, when the visual stimulus in a sentence-picture matching task is a minimal model abstracting away from the details of the situation, children often regard all the elements of the stimulus as ostensive clues to be represented in the corresponding sentence. The use of such minimal stimuli is mistaken when the experiment aims to test whether or not a certain element of the stimulus is relevant for the linguistic representation or interpretation. The paper illustrates this point by an experiment involving quantifier spreading. It is claimed that children find a universally quantified sentence like 'Every girl is riding a bicycle 'to be a false description of a picture showing three girls riding bicycles and a solo bicycle because they are misled to believe that all the elements in the visual stimulus are relevant, hence all of them are to be represented by the corresponding linguistic description. When the iconic drawings were replaced by photos taken in a natural environment rich in accidental details, the occurrence of quantifier spreading was radically reduced. It is shown that an extra object in the visual stimulus can lead to the rejection of the sentence also in the case of sentences involving no quantification, which gives further support to the claim that the source of the problem is not (or not only the grammatical or cognitive difficulty of quantification but the unintended ostensive effect of the extra object.  This article is part of the special collection: Acquisition of Quantification

  19. Clinical outcome of narrow diameter implants inserted into allografts

    Directory of Open Access Journals (Sweden)

    Maurizio Franco

    2009-08-01

    Full Text Available OBJECTIVE: Narrow diameter implants (NDI (i.e. diameter <3.75 mm are a potential solution for specific clinical situations, such as reduced interradicular bone, thin alveolar crest and replacement of teeth with small cervical diameter. NDI have been available in clinical practice since the 1990s, but only few studies have analyzed their clinical outcome and no study have investigated NDI inserted in fresh-frozen bone (FFB grafts. Thus, a retrospective study on a series of NDI placed in homologue FFB was designed to evaluate their clinical outcome. MATERIAL AND METHODS: In the period between December 2003 and December 2006, 36 patients (22 females and 14 males, mean age 53 years with FFB grafts were selected and 94 different NDI were inserted. The mean follow-up was 25 months. To evaluate the effect of several host-, surgery-, and implant-related factors, marginal bone loss (MBL was considered an indicator of success rate (SCR. The Kaplan Meier algorithm and Cox regression were used. RESULTS: Only 5 out of 94 implants were lost (i.e. survival rate - SVR 95.7% and no differences were detected among the studied variables. On the contrary, the Cox regression showed that the graft site (i.e. maxilla reduced MBL. CONCLUSIONS: NDI inserted in FFB have a high SVR and SCR similar to those reported in previous studies on regular and NDI inserted in non-grafted jaws. Homologue FFB is a valuable material in the insertion of NDI.

  20. 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)

  1. Improved Design Basis for Laterally Loaded Large Diameter Pile

    DEFF Research Database (Denmark)

    Leth, Caspar Thrane

    of up-to-date facilities has been: Equipment for controlling centrifuge tests, data acquisition, preparation of test samples and equipment for and making of lateral load tests. The present research has been narrowed to investigate the static and cyclic behaviour of stiff piles with a diameter of 1-3 m...... in dry sand by use of centrifuge modelling and to compare the findings with the standard p-y curves. It has been chosen to apply piles with an embedment length of 6 to 10 times the diameter of the applied piles. The general static behaviour of monopiles in dry sand has based on centrifuge tests been...... with a capacity of 3.6 MW and placed at water depths beyond 25 m. Different foundation solutions have over the years been applied for offshore turbines, but monopiles are currently the most applied foundation type and are typically with a pile diameter of 4-6 m and applied up to a water depth of 25 m...

  2. Tree height-diameter allometry across the United States.

    Science.gov (United States)

    Hulshof, Catherine M; Swenson, Nathan G; Weiser, Michael D

    2015-03-01

    The relationship between tree height and diameter is fundamental in determining community and ecosystem structure as well as estimates of biomass and carbon storage. Yet our understanding of how tree allometry relates to climate and whole organismal function is limited. We used the Forest Inventory and Analysis National Program database to determine height-diameter allometries of 2,976,937 individuals of 293 tree species across the United States. The shape of the allometric relationship was determined by comparing linear and nonlinear functional forms. Mixed-effects models were used to test for allometric differences due to climate and floristic (between angiosperms and gymnosperms) and functional groups (leaf habit and shade tolerance). Tree allometry significantly differed across the United States largely because of climate. Temperature, and to some extent precipitation, in part explained tree allometric variation. The magnitude of allometric variation due to climate, however, had a phylogenetic signal. Specifically, angiosperm allometry was more sensitive to differences in temperature compared to gymnosperms. Most notably, angiosperm height was more negatively influenced by increasing temperature variability, whereas gymnosperm height was negatively influenced by decreasing precipitation and increasing altitude. There was little evidence to suggest that shade tolerance influenced tree allometry except for very shade-intolerant trees which were taller for any given diameter. Tree allometry is plastic rather than fixed and scaling parameters vary around predicted central tendencies. This allometric variation provides insight into life-history strategies, phylogenetic history, and environmental limitations at biogeographical scales.

  3. Tree height–diameter allometry across the United States

    Science.gov (United States)

    Hulshof, Catherine M; Swenson, Nathan G; Weiser, Michael D

    2015-01-01

    The relationship between tree height and diameter is fundamental in determining community and ecosystem structure as well as estimates of biomass and carbon storage. Yet our understanding of how tree allometry relates to climate and whole organismal function is limited. We used the Forest Inventory and Analysis National Program database to determine height–diameter allometries of 2,976,937 individuals of 293 tree species across the United States. The shape of the allometric relationship was determined by comparing linear and nonlinear functional forms. Mixed-effects models were used to test for allometric differences due to climate and floristic (between angiosperms and gymnosperms) and functional groups (leaf habit and shade tolerance). Tree allometry significantly differed across the United States largely because of climate. Temperature, and to some extent precipitation, in part explained tree allometric variation. The magnitude of allometric variation due to climate, however, had a phylogenetic signal. Specifically, angiosperm allometry was more sensitive to differences in temperature compared to gymnosperms. Most notably, angiosperm height was more negatively influenced by increasing temperature variability, whereas gymnosperm height was negatively influenced by decreasing precipitation and increasing altitude. There was little evidence to suggest that shade tolerance influenced tree allometry except for very shade-intolerant trees which were taller for any given diameter. Tree allometry is plastic rather than fixed and scaling parameters vary around predicted central tendencies. This allometric variation provides insight into life-history strategies, phylogenetic history, and environmental limitations at biogeographical scales. PMID:25859325

  4. Topology dependent epidemic spreading velocity in weighted networks

    International Nuclear Information System (INIS)

    Duan, Wei; Qiu, Xiaogang; Quax, Rick; Lees, Michael; Sloot, Peter M A

    2014-01-01

    Many diffusive processes occur on structured networks with weighted links, such as disease spread by airplane transport or information diffusion in social networks or blogs. Understanding the impact of weight-connectivity correlations on epidemic spreading in weighted networks is crucial to support decision-making on disease control and other diffusive processes. However, a real understanding of epidemic spreading velocity in weighted networks is still lacking. Here we conduct a numerical study of the velocity of a Reed–Frost epidemic spreading process in various weighted network topologies as a function of the correlations between edge weights and node degrees. We find that a positive weight-connectivity correlation leads to a faster epidemic spreading compared to an unweighted network. In contrast, we find that both uncorrelated and negatively correlated weight distributions lead to slower spreading processes. In the case of positive weight-connectivity correlations, the acceleration of spreading velocity is weak when the heterogeneity of weight distribution increases. (paper)

  5. Non-isothermal spreading of liquid drops on horizontal plates

    International Nuclear Information System (INIS)

    Ehrhard, P.; Davis, S.H.

    1990-05-01

    A viscous-liquid drop spreads on a smooth horizontal surface, which is uniformly heated or cooled. Lubrication theory is used to study thin drops subject to capillary, thermocapillary and gravity forces, and a variety of contact-angle-versus-speed conditions. It is found for isothermal drops that gravity is very important at large times and determines the power law for unlimited spreading. Predictions compare well with the experimental data on isothermal spreading for both two-dimensional and axisymmetric configurations. It is found that heating (cooling) retards (augments) the spreading process. When the advancing contact angle is zero, heating will cause the drop to spread only finitely far. For positive advancing contact angles, sufficient cooling will cause unlimited spreading. Thus, the heat transfer serves as a sentitive control on the spreading. (orig.) [de

  6. FACTORS INFLUENCING YIELD SPREADS OF THE MALAYSIAN BONDS

    Directory of Open Access Journals (Sweden)

    Norliza Ahmad

    2009-01-01

    Full Text Available Malaysian bond market is developing rapidly but not much is understood in terms of macroeconomic factors that could influence the yield spread of the Ringgit Malaysian denominated bonds. Based on a multifactor model, this paper examines the impact of four macroeconomic factors namely: Kuala Lumpur Composite Index (KLCI, Industry Production Index (IPI, Consumer Price Index (CPI and interest rates (IR on bond yield spread of the Malaysian Government Securities (MGS and Corporate Bonds (CBs for a period from January 2001 to December 2008. The findings support the expected hypotheses that CPI and IR are the major drivers that influence the changes in MGS yield spreads. However IPI and KLCI have weak and no influence on MGS yield spreads respectively Whilst IR, CPI and IPI have significant influence on the yield spreads of CB1, CB2 and CB3, KLCI has significant influence only on the CB1 yield spread but not on CB2 and CB3 yield spreads.

  7. Two-point method uncertainty during control and measurement of cylindrical element diameters

    Science.gov (United States)

    Glukhov, V. I.; Shalay, V. V.; Radev, H.

    2018-04-01

    The topic of the article is devoted to the urgent problem of the reliability of technical products geometric specifications measurements. The purpose of the article is to improve the quality of parts linear sizes control by the two-point measurement method. The article task is to investigate methodical extended uncertainties in measuring cylindrical element linear sizes. The investigation method is a geometric modeling of the element surfaces shape and location deviations in a rectangular coordinate system. The studies were carried out for elements of various service use, taking into account their informativeness, corresponding to the kinematic pairs classes in theoretical mechanics and the number of constrained degrees of freedom in the datum element function. Cylindrical elements with informativity of 4, 2, 1 and θ (zero) were investigated. The uncertainties estimation of in two-point measurements was made by comparing the results of of linear dimensions measurements with the functional diameters maximum and minimum of the element material. Methodical uncertainty is formed when cylindrical elements with maximum informativeness have shape deviations of the cut and the curvature types. Methodical uncertainty is formed by measuring the element average size for all types of shape deviations. The two-point measurement method cannot take into account the location deviations of a dimensional element, so its use for elements with informativeness less than the maximum creates unacceptable methodical uncertainties in measurements of the maximum, minimum and medium linear dimensions. Similar methodical uncertainties also exist in the arbitration control of the linear dimensions of the cylindrical elements by limiting two-point gauges.

  8. Wiener index and Diameter of a Planar Graph in Subquadratic Time

    DEFF Research Database (Denmark)

    Wulff-Nilsen, Christian

    2009-01-01

    Consider the problem of computing the sum of distances between each pair of vertices of an unweighted graph. This sum is also known as the Wiener index of the graph, a generalization of a definition given by H. Wiener in 1947. A molecular topological index is a value obtained from the graph...... structure of a molecule such that this value (hopefully) correlates with physical and/or chemical properties of the molecule. The Wiener index is perhaps the most studied molecular topological index with more than a thousand publications. It is open whether the Wiener index of a planar graph can be obtained...... in subquadratic time. In my talk, I will solve this open problem by exhibiting an O(n2 log log n / log n) time algorithm, where n is the size of the graph. A simple modification yields an algorithm with the same time bound that computes the diameter (maximum distance between any vertex pair) of a planar graph. I...

  9. Opposed-Flow Flame Spread over Thin Solid Fuels in a Narrow Channel under Different Gravity

    Science.gov (United States)

    Zhang, Xia; Yu, Yong; Wan, Shixin; Wei, Minggang; Hu, Wen-Rui

    microgravity. This showed that the horizontal narrow channel can restrict natural convection effectively. In the vertical narrow channel, flame spread became slower as the forced gas flow speed increased. In low speed gas flows, flame spread was not near quench limit. Instead, the spread rate got its maximum value. This was entirely different from the result of microgravity and showed that the vertical narrow channel can not restrict natural convection. For the horizontal narrow channel, when the channel height lowered to 1 cm (The Grashof number was 149 using the half height as a characteristic length), the natural convection was restricted. For vertical narrow channel, a lower height was needed to restrict natural convection. References 1. NASA Technical Standard, "Flammability, Odor, Offgassing, and Compatibility Require-ments and Test Procedures for Materials in Environments That Support Combustion", NASA STD-6001, 1998. 2. Ivanov, A. V., Balashov, Ye. V., Andreeva, T. V., and et al., "Experimental Verification of Material Flammability in Space", NASA CR-1999-209405, 1999. 3. Melikhov, A. S., Bolodyan, I. A., Potyakin, V. I., and et al., "The study of polymer material combustion in simulated microgravity by physical modeling method", In: Sacksteder K, ed, "Fifth Int Microgravity Comb Workshop", NASA CP-1999-208917, 1999, 361. 4. T'ien, J. S., Shih, H.-Y., Jiang, C.-B., and et al., "Mechanisms of flame spread and smol-der wave propagation", In: Ross, H. D., ed, "Microgravity Combustion: Fire in Free Fall", Academic Press, 2001. 299. 5. Olson, S. L., Comb Sci Tech, 76, 233, 1991.

  10. Ultrasonographic criteria for fine needle aspiration of nonpalpable thyroid nodules 1–2 cm in diameter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Yang, E-mail: j0kim040@louisville.edu [Department of Radiology, University of Louisville, 530 South Jackson Street, Louisville, KY 40242 (United States); Department of Healthcare System Gangnam Center, Department of Radiology, Seoul National University Hospital, 737 Star tower, 40 floor, Yeoksam-dong, Gangnam-gu, Seoul 135-080 (Korea, Republic of); Kim, Soo Young; Yang, Ki Ra [Department of Healthcare System Gangnam Center, Department of Radiology, Seoul National University Hospital, 737 Star tower, 40 floor, Yeoksam-dong, Gangnam-gu, Seoul 135-080 (Korea, Republic of)

    2013-02-15

    Purpose: To investigate the ultrasonographic (US) characteristics for nonpalpable thyroid nodules 1–2 cm in diameter and to evaluate the guideline for fine needle aspiration (FNA) in terms of US findings. Materials and methods: Between June 2005 and November 2006, FNA was performed in 919 thyroid nodules by radiologists. Of these nodules, 51 malignant nodules and 72 benign nodules were finally included. All 123 nodules were analyzed by 3 radiologists if there were the following US characteristics: marked hypoechogenecity, hypoechogenecity, isoechogenecity, hyperechogenecity, microcalcification, coarse calcification, rim calcification, spiculated margin, taller-than-wide shape, irregular shape, hypoechoic rim and honeycomb appearance. The maximum diameters of nodules and thickness of hypoechoic rim were measured. US characteristics relevant as predictors were identified using a Chi-square or Fisher's exact test and odds ratio. We compared the diagnostic efficacy of 3 US criteria for FNA indication. Results: Microcalcification, taller-than-wide shape, marked hypoechogenecity, hypoechogenecity, coarse calcification, irregular shape and spiculated margin were significant characteristics of malignant nodules. Isoechogenecity, hypoechoic rim and honeycomb appearance was significant characteristics of benign nodules. Rim or arc calcification, hyperechogenecity and thickness of hypoechoic rim were insignificant. Among 3 US criteria for FNA indication, NFI showed the highest diagnostic efficacy, 98.0% in sensitivity, 75.0% in specificity and 150.0 in odds ratio. Conclusion: As for nonpalpable thyroid nodules 1–2 cm in diameter, US characteristics are useful for differentiating between malignant and benign nodules. Malignant US characteristics and honeycombing appearance have significant value in selecting nodules for biopsy and reducing the frequency of the FNA procedure.

  11. Experiment on a large-diameter plasma-filled backward-wave oscillator

    International Nuclear Information System (INIS)

    Ogura, K.; Minami, K.; Kurashina, K.I.; Kim, W.; Watanabe, T.; Ishii, K.; Sugito, S.

    1995-01-01

    A large-diameter plasma-filled backward-wave oscillator (BWO) is investigated experimentally. The parameters of slow wave structure are chosen so that the oscillation frequency is about 20GHz at 60keV beam energy. Plasma is produced by the beam and has favorable effects for beam propagation and Cerenkov oscillations. The output power of the BWO with plasma is observed to be three to six times that of vacuum BWO. The power level is several kilowatts and the efficiency is about 0.01%. For Cerenkov oscillations of a large-diameter BWO, the beam energy mainly determines the starting conditions for oscillation. The output power is strongly enhanced when the guiding magnetic field approaches the fundamental electron cyclotron resonance. This mechanism is closely related to the anomalous Doppler cyclotron resonance. The maximum power of 480kW with an efficiency of 5% is achieved even for a relatively low beam energy of 60keV. ((orig.))

  12. Geometric interpretation of the ratio of overall diameter to rim crest diameter for lunar and terrestrial craters.

    Science.gov (United States)

    Siegal, B. S.; Wickman, F. E.

    1973-01-01

    An empirical linear relationship has been established by Pike (1967) between the overall diameter and the rim crest diameter for rimmed, flat-floored as well as bowl-shaped, lunar and terrestrial craters formed by impact and explosion. A similar relationship for experimentally formed fluidization craters has been established by Siegal (1971). This relationship is examined in terms of the geometry of the crater and the slope angles of loose materials. The parameter varies from 1.40 to 1.65 and is found to be dependent on mean interior flat floor radius, exterior and interior rim slope angles, angle of aperture of the crater cone, and the volume fraction of crater void accounted for in the rim. The range of the observed parameter can be understood in terms of simple crater geometry by realistic values of the five parameters.

  13. Maximum concentrations at work and maximum biologically tolerable concentration for working materials 1991

    International Nuclear Information System (INIS)

    1991-01-01

    The meaning of the term 'maximum concentration at work' in regard of various pollutants is discussed. Specifically, a number of dusts and smokes are dealt with. The valuation criteria for maximum biologically tolerable concentrations for working materials are indicated. The working materials in question are corcinogeneous substances or substances liable to cause allergies or mutate the genome. (VT) [de

  14. 75 FR 43840 - Inflation Adjustment of the Ordinary Maximum and Aggravated Maximum Civil Monetary Penalties for...

    Science.gov (United States)

    2010-07-27

    ...-17530; Notice No. 2] RIN 2130-ZA03 Inflation Adjustment of the Ordinary Maximum and Aggravated Maximum... remains at $250. These adjustments are required by the Federal Civil Penalties Inflation Adjustment Act [email protected] . SUPPLEMENTARY INFORMATION: The Federal Civil Penalties Inflation Adjustment Act of 1990...

  15. Zipf's law, power laws and maximum entropy

    International Nuclear Information System (INIS)

    Visser, Matt

    2013-01-01

    Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified. (paper)

  16. Maximum-entropy description of animal movement.

    Science.gov (United States)

    Fleming, Chris H; Subaşı, Yiğit; Calabrese, Justin M

    2015-03-01

    We introduce a class of maximum-entropy states that naturally includes within it all of the major continuous-time stochastic processes that have been applied to animal movement, including Brownian motion, Ornstein-Uhlenbeck motion, integrated Ornstein-Uhlenbeck motion, a recently discovered hybrid of the previous models, and a new model that describes central-place foraging. We are also able to predict a further hierarchy of new models that will emerge as data quality improves to better resolve the underlying continuity of animal movement. Finally, we also show that Langevin equations must obey a fluctuation-dissipation theorem to generate processes that fall from this class of maximum-entropy distributions when the constraints are purely kinematic.

  17. Pareto versus lognormal: a maximum entropy test.

    Science.gov (United States)

    Bee, Marco; Riccaboni, Massimo; Schiavo, Stefano

    2011-08-01

    It is commonly found that distributions that seem to be lognormal over a broad range change to a power-law (Pareto) distribution for the last few percentiles. The distributions of many physical, natural, and social events (earthquake size, species abundance, income and wealth, as well as file, city, and firm sizes) display this structure. We present a test for the occurrence of power-law tails in statistical distributions based on maximum entropy. This methodology allows one to identify the true data-generating processes even in the case when it is neither lognormal nor Pareto. The maximum entropy approach is then compared with other widely used methods and applied to different levels of aggregation of complex systems. Our results provide support for the theory that distributions with lognormal body and Pareto tail can be generated as mixtures of lognormally distributed units.

  18. Maximum likelihood estimation for integrated diffusion processes

    DEFF Research Database (Denmark)

    Baltazar-Larios, Fernando; Sørensen, Michael

    We propose a method for obtaining maximum likelihood estimates of parameters in diffusion models when the data is a discrete time sample of the integral of the process, while no direct observations of the process itself are available. The data are, moreover, assumed to be contaminated...... EM-algorithm to obtain maximum likelihood estimates of the parameters in the diffusion model. As part of the algorithm, we use a recent simple method for approximate simulation of diffusion bridges. In simulation studies for the Ornstein-Uhlenbeck process and the CIR process the proposed method works...... by measurement errors. Integrated volatility is an example of this type of observations. Another example is ice-core data on oxygen isotopes used to investigate paleo-temperatures. The data can be viewed as incomplete observations of a model with a tractable likelihood function. Therefore we propose a simulated...

  19. A Maximum Radius for Habitable Planets.

    Science.gov (United States)

    Alibert, Yann

    2015-09-01

    We compute the maximum radius a planet can have in order to fulfill two constraints that are likely necessary conditions for habitability: 1- surface temperature and pressure compatible with the existence of liquid water, and 2- no ice layer at the bottom of a putative global ocean, that would prevent the operation of the geologic carbon cycle to operate. We demonstrate that, above a given radius, these two constraints cannot be met: in the Super-Earth mass range (1-12 Mearth), the overall maximum that a planet can have varies between 1.8 and 2.3 Rearth. This radius is reduced when considering planets with higher Fe/Si ratios, and taking into account irradiation effects on the structure of the gas envelope.

  20. Maximum parsimony on subsets of taxa.

    Science.gov (United States)

    Fischer, Mareike; Thatte, Bhalchandra D

    2009-09-21

    In this paper we investigate mathematical questions concerning the reliability (reconstruction accuracy) of Fitch's maximum parsimony algorithm for reconstructing the ancestral state given a phylogenetic tree and a character. In particular, we consider the question whether the maximum parsimony method applied to a subset of taxa can reconstruct the ancestral state of the root more accurately than when applied to all taxa, and we give an example showing that this indeed is possible. A surprising feature of our example is that ignoring a taxon closer to the root improves the reliability of the method. On the other hand, in the case of the two-state symmetric substitution model, we answer affirmatively a conjecture of Li, Steel and Zhang which states that under a molecular clock the probability that the state at a single taxon is a correct guess of the ancestral state is a lower bound on the reconstruction accuracy of Fitch's method applied to all taxa.

  1. Maximum entropy analysis of liquid diffraction data

    International Nuclear Information System (INIS)

    Root, J.H.; Egelstaff, P.A.; Nickel, B.G.

    1986-01-01

    A maximum entropy method for reducing truncation effects in the inverse Fourier transform of structure factor, S(q), to pair correlation function, g(r), is described. The advantages and limitations of the method are explored with the PY hard sphere structure factor as model input data. An example using real data on liquid chlorine, is then presented. It is seen that spurious structure is greatly reduced in comparison to traditional Fourier transform methods. (author)

  2. The transverse diameter of the chest on routine radiographs reliably estimates gestational age and weight in premature infants

    Energy Technology Data Exchange (ETDEWEB)

    Dietz, Kelly R. [University of Minnesota, Department of Radiology, Minneapolis, MN (United States); Zhang, Lei [University of Minnesota, Biostatistical Design and Analysis Center, Minneapolis, MN (United States); Seidel, Frank G. [Lucile Packard Children' s Hospital, Department of Radiology, Stanford, CA (United States)

    2015-08-15

    Prior to digital radiography it was possible for a radiologist to easily estimate the size of a patient on an analog film. Because variable magnification may be applied at the time of processing an image, it is now more difficult to visually estimate an infant's size on the monitor. Since gestational age and weight significantly impact the differential diagnosis of neonatal diseases and determine the expected size of kidneys or appearance of the brain by MRI or US, this information is useful to a pediatric radiologist. Although this information may be present in the electronic medical record, it is frequently not readily available to the pediatric radiologist at the time of image interpretation. To determine if there was a correlation between gestational age and weight of a premature infant with their transverse chest diameter (rib to rib) on admission chest radiographs. This retrospective study was approved by the institutional review board, which waived informed consent. The maximum transverse chest diameter outer rib to outer rib was measured on admission portable chest radiographs of 464 patients admitted to the neonatal intensive care unit (NICU) during the 2010 calendar year. Regression analysis was used to investigate the association between chest diameter and gestational age/birth weight. Quadratic term of chest diameter was used in the regression model. Chest diameter was statistically significantly associated with both gestational age (P < 0.0001) and birth weight (P < 0.0001). An infant's gestational age and birth weight can be reliably estimated by comparing a simple measurement of the transverse chest diameter on digital chest radiograph with the tables and graphs in our study. (orig.)

  3. Is the biparietal diameter of fetuses in late gestation too variable to predict readiness for cesarean section in dogs?

    Science.gov (United States)

    De Cramer, K G M; Nöthling, J O

    2018-06-01

    Correct assessment of readiness for cesarean section is essential for timing elective cesarean section during late pregnancy in the bitch. In humans, biparietal diameter is sufficiently precise and accurate and used in a clinical setting daily. The objectives of this study were to determine whether fetal biparietal diameter in late gestation in the dog could be used to predict readiness for cesarean section by having reached a minimum cut-off value and to correlate the biparietal diameter to birth weight. The biparietal diameter of 208 puppies in 34 litters from 31 English bulldog bitches and 660 puppies in 78 litters from 70 Boerboel bitches were measured immediately after delivery by cesarean section, performed at full term, using digital calipers. At the same time the birth weight of the same 208 English bulldog puppies and 494 of the same Boerboel puppies in 59 litters from 54 bitches was measured by means of an electronic scale. With a cesarean section, all the puppies in a litter are delivered simultaneously and readiness for cesarean section must be determined for a litter. The minimum, median and maximum biparietal diameter varied from 21.1 to 47.8, 32.9 to 50.0 and 34.2-58.2 mm, respectively, among English bulldog litters and from 18.4 to 48.7, 35.5 to 49.7 and 39.8-54.3 mm among Boerboel litters. This large variation suggests that biparietal diameter is too variable within and among litters to be useful as a means of determining readiness for cesarean section. Copyright © 2018 Elsevier Inc. All rights reserved.

  4. Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Shariat, Masoud; Schantz, Daryl; Yoo, Shi-Joon; Wintersperger, Bernd J.; Seed, Mike; Alnafisi, Bahiyah; Chu, Leysia; MacGowan, Christopher K.; Amerom, Joshua van; Grosse-Wortmann, Lars

    2014-01-01

    Background: Information about thoracic vascular sizes can crucially affect clinical decision-making in cardiovascular disease. A variety of imaging techniques such as catheter angiography, contrast enhanced computed tomography (CT) and cardiac magnetic resonance imaging (CMR) are routinely used to measure vascular diameters. Traditionally, CMR black blood sequences were the main anatomical tool for visualization of vascular anatomy and still are in many centers. More recently, the vessel diameters are measured on multiplanar reconstructions derived from static magnetic resonance angiography (MRA). This study was performed to investigate the variation of vessel diameter measurements on different CMR techniques with respect to their data acquisition scheme. Methods: We recruited two groups of patients for this prospective study. One group included patients with repaired tetralogy of Fallot (TOF), with at least moderate pulmonary insufficiency and another group of patients who underwent CMR as part of a diagnostic work-up for arrhythmogenic right ventricular cardiomyopathy (ARVC). Additional images of the right pulmonary artery (RPA) were acquired in the double inversion recovery (DIR) black blood, cine steady state free precession (SSFP) and MRA. All images were reviewed by two CMR trained readers using the electronic caliper provided within the picture archiving and communication system package. The maximum diameter of each artery was recorded in millimeters with up to one decimal point. Paired t-tests and Bland–Altman plots were used for comparison of measurements between different sequences. Results: A total of 52 patients were recruited for this study, 26 patients in the TOF group (15 males, age 12.55 ± 2.9) and 26 patients in the ARVC group (15 males, age 15.6 ± 2.3). In both groups, the RPA sizes were not significantly different between the DIR images and diastolic cine SSFP (p > 0.05). Measurements on DIR were significantly smaller than those made on

  5. Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shariat, Masoud, E-mail: masoudshariat@gmail.com [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Schantz, Daryl, E-mail: daryl.schantz@gmail.com [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Yoo, Shi-Joon, E-mail: shi-joon.yoo@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Wintersperger, Bernd J., E-mail: bernd.wintersperger@uhn.ca [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Seed, Mike, E-mail: mike.seed@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Department of Cardiology, Hospital for Sick Children, Toronto, Ontario (Canada); Alnafisi, Bahiyah, E-mail: bahiyah.alnafisi@uhn.ca [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Chu, Leysia, E-mail: leysia_99@yahoo.com [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); MacGowan, Christopher K., E-mail: christopher.macgowan@sickkids.ca [Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario (Canada); Amerom, Joshua van, E-mail: Joshu.vanamerom@sickkids.ca [Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario (Canada); Grosse-Wortmann, Lars, E-mail: lars.grosse-wortmann@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Department of Cardiology, Hospital for Sick Children, Toronto, Ontario (Canada)

    2014-02-15

    Background: Information about thoracic vascular sizes can crucially affect clinical decision-making in cardiovascular disease. A variety of imaging techniques such as catheter angiography, contrast enhanced computed tomography (CT) and cardiac magnetic resonance imaging (CMR) are routinely used to measure vascular diameters. Traditionally, CMR black blood sequences were the main anatomical tool for visualization of vascular anatomy and still are in many centers. More recently, the vessel diameters are measured on multiplanar reconstructions derived from static magnetic resonance angiography (MRA). This study was performed to investigate the variation of vessel diameter measurements on different CMR techniques with respect to their data acquisition scheme. Methods: We recruited two groups of patients for this prospective study. One group included patients with repaired tetralogy of Fallot (TOF), with at least moderate pulmonary insufficiency and another group of patients who underwent CMR as part of a diagnostic work-up for arrhythmogenic right ventricular cardiomyopathy (ARVC). Additional images of the right pulmonary artery (RPA) were acquired in the double inversion recovery (DIR) black blood, cine steady state free precession (SSFP) and MRA. All images were reviewed by two CMR trained readers using the electronic caliper provided within the picture archiving and communication system package. The maximum diameter of each artery was recorded in millimeters with up to one decimal point. Paired t-tests and Bland–Altman plots were used for comparison of measurements between different sequences. Results: A total of 52 patients were recruited for this study, 26 patients in the TOF group (15 males, age 12.55 ± 2.9) and 26 patients in the ARVC group (15 males, age 15.6 ± 2.3). In both groups, the RPA sizes were not significantly different between the DIR images and diastolic cine SSFP (p > 0.05). Measurements on DIR were significantly smaller than those made on

  6. A Maximum Resonant Set of Polyomino Graphs

    Directory of Open Access Journals (Sweden)

    Zhang Heping

    2016-05-01

    Full Text Available A polyomino graph P is a connected finite subgraph of the infinite plane grid such that each finite face is surrounded by a regular square of side length one and each edge belongs to at least one square. A dimer covering of P corresponds to a perfect matching. Different dimer coverings can interact via an alternating cycle (or square with respect to them. A set of disjoint squares of P is a resonant set if P has a perfect matching M so that each one of those squares is M-alternating. In this paper, we show that if K is a maximum resonant set of P, then P − K has a unique perfect matching. We further prove that the maximum forcing number of a polyomino graph is equal to the cardinality of a maximum resonant set. This confirms a conjecture of Xu et al. [26]. We also show that if K is a maximal alternating set of P, then P − K has a unique perfect matching.

  7. Automatic maximum entropy spectral reconstruction in NMR

    International Nuclear Information System (INIS)

    Mobli, Mehdi; Maciejewski, Mark W.; Gryk, Michael R.; Hoch, Jeffrey C.

    2007-01-01

    Developments in superconducting magnets, cryogenic probes, isotope labeling strategies, and sophisticated pulse sequences together have enabled the application, in principle, of high-resolution NMR spectroscopy to biomolecular systems approaching 1 megadalton. In practice, however, conventional approaches to NMR that utilize the fast Fourier transform, which require data collected at uniform time intervals, result in prohibitively lengthy data collection times in order to achieve the full resolution afforded by high field magnets. A variety of approaches that involve nonuniform sampling have been proposed, each utilizing a non-Fourier method of spectrum analysis. A very general non-Fourier method that is capable of utilizing data collected using any of the proposed nonuniform sampling strategies is maximum entropy reconstruction. A limiting factor in the adoption of maximum entropy reconstruction in NMR has been the need to specify non-intuitive parameters. Here we describe a fully automated system for maximum entropy reconstruction that requires no user-specified parameters. A web-accessible script generator provides the user interface to the system

  8. maximum neutron flux at thermal nuclear reactors

    International Nuclear Information System (INIS)

    Strugar, P.

    1968-10-01

    Since actual research reactors are technically complicated and expensive facilities it is important to achieve savings by appropriate reactor lattice configurations. There is a number of papers, and practical examples of reactors with central reflector, dealing with spatial distribution of fuel elements which would result in higher neutron flux. Common disadvantage of all the solutions is that the choice of best solution is done starting from the anticipated spatial distributions of fuel elements. The weakness of these approaches is lack of defined optimization criteria. Direct approach is defined as follows: determine the spatial distribution of fuel concentration starting from the condition of maximum neutron flux by fulfilling the thermal constraints. Thus the problem of determining the maximum neutron flux is solving a variational problem which is beyond the possibilities of classical variational calculation. This variational problem has been successfully solved by applying the maximum principle of Pontrjagin. Optimum distribution of fuel concentration was obtained in explicit analytical form. Thus, spatial distribution of the neutron flux and critical dimensions of quite complex reactor system are calculated in a relatively simple way. In addition to the fact that the results are innovative this approach is interesting because of the optimization procedure itself [sr

  9. Risk spreading, connectivity, and optimal reserve spacing.

    Science.gov (United States)

    Blowes, Shane A; Connolly, Sean R

    2012-01-01

    Two important processes determining the dynamics of spatially structured populations are dispersal and the spatial covariance of demographic fluctuations. Spatially explicit approaches to conservation, such as reserve networks, must consider the tension between these two processes and reach a balance between distances near enough to maintain connectivity, but far enough to benefit from risk spreading. Here, we model this trade-off. We show how two measures of metapopulation persistence depend on the shape of the dispersal kernel and the shape of the distance decay in demographic covariance, and we consider the implications of this trade-off for reserve spacing. The relative rates of distance decay in dispersal and demographic covariance determine whether the long-run metapopulation growth rate, and quasi-extinction risk, peak for adjacent patches or intermediately spaced patches; two local maxima in metapopulation persistence are also possible. When dispersal itself fluctuates over time, the trade-off changes. Temporal variation in mean distance that propagules are dispersed (i.e., propagule advection) decreases metapopulation persistence and decreases the likelihood that persistence will peak for adjacent patches. Conversely, variation in diffusion (the extent of random spread around mean dispersal) increases metapopulation persistence overall and causes it to peak at shorter inter-patch distances. Thus, failure to consider temporal variation in dispersal processes increases the risk that reserve spacings will fail to meet the objective of ensuring metapopulation persistence. This study identifies two phenomena that receive relatively little attention in empirical work on reserve spacing, but that can qualitatively change the effectiveness of reserve spacing strategies: (1) the functional form of the distance decay in covariance among patch-specific demographic rates and (2) temporal variation in the shape of the dispersal kernel. The sensitivity of metapopulation

  10. A comparison of hydraulic architecture in three similarly sized woody species differing in their maximum potential height

    Science.gov (United States)

    Katherine A. McCulloh; Daniel M. Johnson; Joshua Petitmermet; Brandon McNellis; Frederick C. Meinzer; Barbara Lachenbruch; Nathan Phillips

    2015-01-01

    The physiological mechanisms underlying the short maximum height of shrubs are not understood. One possible explanation is that differences in the hydraulic architecture of shrubs compared with co-occurring taller trees prevent the shrubs from growing taller. To explore this hypothesis, we examined various hydraulic parameters, including vessel lumen diameter,...

  11. Fabricated nano-fiber diameter as liquid concentration sensors

    Science.gov (United States)

    Chyad, Radhi M.; Mat Jafri, Mohd Zubir; Ibrahim, Kamarulazizi

    Nanofiber is characterized by thin, long, and very soft silica. Taper fibers are made using an easy and low cost chemical method. Etching is conducted with a HF solution to remove cladding and then a low molarity HF solution to reduce the fiber core diameter. One approach to on-line monitoring of the etching process uses spectrophotometer with a white light source. In the aforementioned technique, this method aims to determine the diameter of the reduced core and show the evolution of the two different processes from the nanofiber regime to the fixed regime in which the mode was remote from the surrounding evanescent field, intensity can propagate outside the segment fiber when the core diameter is less than 500 nm. Manufacturing technologies of nano-fiber sensors offer a number of approved properties of optical fiber sensors utilized in various sensory applications. The nano-fiber sensor is utilized to sense the difference in the concentration of D-glucose in double-distilled deionized water and to measure the refractive index (RI) of a sugar solution. Our proposed method exhibited satisfactory capability based on bimolecular interactions in the biological system. The response of the nano-fiber sensors indicates a different kind of interaction among various groups of AAs. These results can be interpreted in terms of solute-solute and solute-solvent interactions and the structure making or breaking ability of solutes in the given solution. This study utilized spectra photonics to measure the transmission of light through different concentrations of sugar solution, employing cell cumber and nano-optical fibers as sensors.

  12. Forming of Zr-4 alloy guide tube with varied diameters

    International Nuclear Information System (INIS)

    Wei Songyan; Tian Zhenye

    1989-10-01

    A new built-up mould method to manufacture Zr-4 alloy guide tubes with varied diameters at the middle of tube is introduced. The guide tube is used in nuclear power plants for guiding the control rods. This method has many advantages such as simple in forming, low cost of manufacturing, no need of special devices and favour of batch processing. The test results show that the accuracy of size, mechanical properties, resistance to corrosion, grain size and hydrogenate orientation of the end-products can meet the technical needs for nuclear reactor operation

  13. Bubble departure diameter in narrow rectangular channel under rolling condition

    Energy Technology Data Exchange (ETDEWEB)

    Xie, T.; Chen, B.; Yan, X.; Xu, J.; Huang, Y.; Xiao, Z. [Nuclear Power Inst. of China, Chengdu, Sichuan (China)

    2014-07-01

    Forced convective subcooled boiling flow experiments were conducted in a vertical upward narrow rectangular channel under rolling motion. A high-speed digital video camera was used to capture the dynamics of the bubble nucleation process. Bubble departure diameters were obtained from the images. A bubble departure model based on force balance analysis was proposed to predict the bubble departure size under rolling condition by considering the additional centrifugal, tangential and Coriolis force. The proposed model agreed well with the experimental data within the averaged relative deviation of 5%. (author)

  14. Base metal thermocouples drift rate dependence from thermoelement diameter

    International Nuclear Information System (INIS)

    Pavlasek, P; Duris, S; Palencar, R

    2015-01-01

    Temperature measurements are one of the key factors in many industrial applications that directly affect the quality, effectiveness and safety of manufacturing processes. In many industrial applications these temperature measurements are realized by thermocouples. Accuracy of thermocouples directly affects the quality of the final product of manufacturing and their durability determines the safety margins required. One of the significant effects that affect the precision of the thermocouples is short and long term stability of their voltage output. This stability issue occurs in every type of thermocouples and is caused by multiple factors. In general these factors affect the Seebeck coefficient which is a material constant, which determines the level of generated voltage when exposed to a temperature gradient. Changes of this constant result in the change of the thermocouples voltage output thus indicated temperature which can result in production quality issues, safety and health hazards. These alternations can be caused by physical and chemical changes within the thermocouple lead material. Modification of this material constant can be of temporary nature or permanent. This paper concentrates on the permanent, or irreversible changes of the Seebeck coefficient that occur in commonly used swaged MIMS Type N thermocouples. These permanent changes can be seen as systematic change of the EMF of the thermocouple when it is exposed to a high temperature over a period of time. This change of EMF by time is commonly known as the drift of the thermocouple. This work deals with the time instability of thermocouples EMF at temperatures above 1200 °C. Instability of the output voltage was taken into relation with the lead diameter of the tested thermocouples. This paper concentrates in detail on the change of voltage output of thermocouples of different diameters which were tested at high temperatures for the overall period of more than 210 hours. The gather data from this

  15. SERS Raman Sensor Based on Diameter-Modulated Sapphire Fiber

    Energy Technology Data Exchange (ETDEWEB)

    Shimoji, Yutaka

    2010-08-09

    Surface enhanced Raman scattering (SERS) has been observed using a sapphire fiber coated with gold nano-islands for the first time. The effect was found to be much weaker than what was observed with a similar fiber coated with silver nanoparticles. Diameter-modulated sapphire fibers have been successfully fabricated on a laser heated pedestal growth system. Such fibers have been found to give a modest increase in the collection efficiency of induced emission. However, the slow response of the SERS effect makes it unsuitable for process control applications.

  16. Base metal thermocouples drift rate dependence from thermoelement diameter

    Science.gov (United States)

    Pavlasek, P.; Duris, S.; Palencar, R.

    2015-02-01

    Temperature measurements are one of the key factors in many industrial applications that directly affect the quality, effectiveness and safety of manufacturing processes. In many industrial applications these temperature measurements are realized by thermocouples. Accuracy of thermocouples directly affects the quality of the final product of manufacturing and their durability determines the safety margins required. One of the significant effects that affect the precision of the thermocouples is short and long term stability of their voltage output. This stability issue occurs in every type of thermocouples and is caused by multiple factors. In general these factors affect the Seebeck coefficient which is a material constant, which determines the level of generated voltage when exposed to a temperature gradient. Changes of this constant result in the change of the thermocouples voltage output thus indicated temperature which can result in production quality issues, safety and health hazards. These alternations can be caused by physical and chemical changes within the thermocouple lead material. Modification of this material constant can be of temporary nature or permanent. This paper concentrates on the permanent, or irreversible changes of the Seebeck coefficient that occur in commonly used swaged MIMS Type N thermocouples. These permanent changes can be seen as systematic change of the EMF of the thermocouple when it is exposed to a high temperature over a period of time. This change of EMF by time is commonly known as the drift of the thermocouple. This work deals with the time instability of thermocouples EMF at temperatures above 1200 °C. Instability of the output voltage was taken into relation with the lead diameter of the tested thermocouples. This paper concentrates in detail on the change of voltage output of thermocouples of different diameters which were tested at high temperatures for the overall period of more than 210 hours. The gather data from this

  17. Evaluation of right atrium-to-right ventricle diameter ratio on computed tomography pulmonary angiography: Prediction of adverse outcome and 30-day mortality.

    Science.gov (United States)

    Oz, Ibrahim Ilker; Altınsoy, Bülent; Serifoglu, Ismail; Sayın, Rasit; Buyukuysal, Mustafa Cagatay; Erboy, Fatma; Akduman, Ece Isin

    2015-12-01

    The aim of this study was to examine the association between right atrium (RA) and right ventricle (RV) diameters on computed tomography (CT) pulmonary angiography in response to acute pulmonary embolism (APE), in addition to 30-day mortality and adverse outcomes in patients with APE. This retrospective study was accepted by the institutional ethics committee. From January 2013 to March 2014, 79 hospitalized adult patients with symptomatic APE were included. Inclusion criteria were a CT pulmonary angiography positive for pulmonary embolism, availability of patient records, and a follow-up of at least 30 days. A review of patient records and images was performed. The maximum diameters of the heart chambers were measured on a reconstructed four-chamber heart view, and the vascular obstruction index was calculated on CT pulmonary angiography. There were statistically significant relationships in both the RA/RV diameter ratio and the RV/left ventricle (LV) diameter ratio between patients with and without adverse outcomes (prights reserved.

  18. Spreading Optics in the primary school

    International Nuclear Information System (INIS)

    Gargallo, Ana; Gómez-Varela, Ana I; Gónzalez-Nuñez, Héctor; Delgado, Tamara; Almaguer, Citlalli; Cambronero, Ferran; García-Sánchez, Ángel; Pallarés, David; Aymerich, María; Aragón, Ángel L; Flores-Arias, Maria T

    2015-01-01

    The USC-OSA is a student chapter located at the University of Santiago de Compostela (Spain) whose objective is to bring optics and photonics knowledge closer to general public. In order to arouse kids' interest in Optics we developed an activity called Funny Light. This activity consisted on a visit of some USC-OSA members to a several local primary schools where we organized several optics experiments. In this work we present the optics demonstrations and the reaction of the 6 years-old students. The activities with greater acceptance include an explanation of light properties as polarization, refraction or reflection, and the workshop where they learnt how to build their own kaleidoscope and made a chromatic disk. Besides, they also participated in a demonstration and explanation of color properties and some optical illusions. We think that this activity has several benefits including spreading Optics through children meanwhile they have fun and experiment science in real life, as well as helping teachers to explain some complex properties and Physics phenomena of light. Given the broad acceptance of this activity, we are intending to make it a routine event of our student chapter repeating it every year. (paper)

  19. Onset conditions for equatorial spread F

    International Nuclear Information System (INIS)

    Mendillo, M.; Baumgardner, J.; Xiaoqing Pi; Sultan, P.J.; Tsunoda, R.

    1992-01-01

    The problem of day-to-day variability in the occurrence of equatorial spread F (ESF) is addressed using multidiagnostic observations and semiempirical modeling. The observational results are derived from a two-night case study of ESF onset conditions observed at Kwajalein Atoll (Marshall Islands) using the ALTAIR incoherent scatter radar and all-sky optical imaging techniques. The major difference between nights when ESF instabilities did not occur (August 14, 1988) and did occur (August 15, 1988) in the Kwajalein sector was that the northern meridional gradient of 6300-angstrom airglow was reduced on the night of limited ESF activity. Modeling results suggest that this unusual airglow pattern is due to equatorward neutral winds. Previous researchers have shown that transequatorial thermospheric winds can exert a control over ESF seasonal and longitudinal occurrence patterns by inhibiting Rayleigh-Taylor instability growth rates. They present evidence to suggest that this picture can be extended to far shorter time scales, namely, that 'surges' in transequatoral winds acting over characteristic times of a few hours to a day can result in a stabilizing influence upon irregularity growth rates. The seemingly capricious nature of ESF onset may thus be controlled, in part, by the inherent variability of low-latitude thermospheric winds

  20. Spreading continents kick-started plate tectonics.

    Science.gov (United States)

    Rey, Patrice F; Coltice, Nicolas; Flament, Nicolas

    2014-09-18

    Stresses acting on cold, thick and negatively buoyant oceanic lithosphere are thought to be crucial to the initiation of subduction and the operation of plate tectonics, which characterizes the present-day geodynamics of the Earth. Because the Earth's interior was hotter in the Archaean eon, the oceanic crust may have been thicker, thereby making the oceanic lithosphere more buoyant than at present, and whether subduction and plate tectonics occurred during this time is ambiguous, both in the geological record and in geodynamic models. Here we show that because the oceanic crust was thick and buoyant, early continents may have produced intra-lithospheric gravitational stresses large enough to drive their gravitational spreading, to initiate subduction at their margins and to trigger episodes of subduction. Our model predicts the co-occurrence of deep to progressively shallower mafic volcanics and arc magmatism within continents in a self-consistent geodynamic framework, explaining the enigmatic multimodal volcanism and tectonic record of Archaean cratons. Moreover, our model predicts a petrological stratification and tectonic structure of the sub-continental lithospheric mantle, two predictions that are consistent with xenolith and seismic studies, respectively, and consistent with the existence of a mid-lithospheric seismic discontinuity. The slow gravitational collapse of early continents could have kick-started transient episodes of plate tectonics until, as the Earth's interior cooled and oceanic lithosphere became heavier, plate tectonics became self-sustaining.