Laser Welding Control

In laser welding of metallic workpieces, the energetic beam is moved over the workpiece surface to form a pool of molten weld metal that quickly solidifies behind the advance of the laser into a weld nugget. The laser beam produces a keyhole of plasma-containing vapor within the molten pool. Weld nugget porosity, due to entrapment of the vapor, is minimized by continually sensing radiation from the molten metal pool to determine pool depth and width and then controlling laser power and speed to continually produce a weld metal pool wide enough for the liquid to fully expel the vapor and solidify into a pore free nugget

Characterization of the Hamamatsu R11410-10 3-Inch Photomultiplier Tube for Liquid Xenon Dark Matter Direct Detection Experiments

To satisfy the requirements of the next generation of dark matter detectors based on the dual phase TPC, Hamamatsu, in close collaboration with UCLA, has developed the R11410-10 photomultipler tube. In this work, we present the detailed tests performed on this device. High QE (>30%) accompanied by a low dark count rate (50 Hz at 0.3 PE) and high gain (10^7) with good single PE resolution have been observed. A comprehensive screening measurement campaign is ongoing while the manufacturer quotes a radioactivity of 20 mBq/PMT. These characteristics show the R11410-10 to be particularly suitable for the forthcoming zero background liquid xenon detectors.Comment: 19 pages, 18 figure

Prevalence, associated factors, and relationship to quality of life of lower urinary tract symptoms: a cross‐sectional, questionnaire survey of cancer patients

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/98277/1/ijcp12141.pd

Yang's gravitational theory

Yang's pure space equations (C.N. Yang, Phys. Rev. Lett. v.33, p.445 (1974)) generalize Einstein's gravitational equations, while coming from gauge theory. We study these equations from a number of vantage points: summarizing the work done previously, comparing them with the Einstein equations and investigating their properties. In particular, the initial value problem is discussed and a number of results are presented for these equations with common energy-momentum tensors.Comment: 28 pages, to appear in Gen. Rel. Gra

Spanning trees on the Sierpinski gasket

We obtain the numbers of spanning trees on the Sierpinski gasket $SG_d(n)$ with dimension $d$ equal to two, three and four. The general expression for the number of spanning trees on $SG_d(n)$ with arbitrary $d$ is conjectured. The numbers of spanning trees on the generalized Sierpinski gasket $SG_{d,b}(n)$ with $d=2$ and $b=3,4$ are also obtained.Comment: 20 pages, 8 figures, 1 tabl

Dimer coverings on the Sierpinski gasket with possible vacancies on the outmost vertices

We present the number of dimers $N_d(n)$ on the Sierpinski gasket $SG_d(n)$ at stage $n$ with dimension $d$ equal to two, three, four or five, where one of the outmost vertices is not covered when the number of vertices $v(n)$ is an odd number. The entropy of absorption of diatomic molecules per site, defined as $S_{SG_d}=\lim_{n \to \infty} \ln N_d(n)/v(n)$, is calculated to be $\ln(2)/3$ exactly for $SG_2(n)$. The numbers of dimers on the generalized Sierpinski gasket $SG_{d,b}(n)$ with $d=2$ and $b=3,4,5$ are also obtained exactly. Their entropies are equal to $\ln(6)/7$, $\ln(28)/12$, $\ln(200)/18$, respectively. The upper and lower bounds for the entropy are derived in terms of the results at a certain stage for $SG_d(n)$ with $d=3,4,5$. As the difference between these bounds converges quickly to zero as the calculated stage increases, the numerical value of $S_{SG_d}$ with $d=3,4,5$ can be evaluated with more than a hundred significant figures accurate.Comment: 35 pages, 20 figures and 1 tabl

High wintertime particulate matter pollution over an offshore island (Kinmen) off southeastern China: an overview

Both the Yangtze River Delta (YRD) and the Pearl River Delta (PRD), the two most rapidly developing areas in eastern China, have suffered from serious air pollution, and thus, numerous investigations were devoted to studying these problems. Other areas in eastern China have received less attention despite similar rapid development in their industries and economy. In this study, we analyzed air‐quality data from Kinmen Island (24°27′26′′N, 118°19′36′′E) located off Fujian Province and between the two above‐mentioned deltas. Our results clearly show that the study area is experiencing serious air quality deterioration. Particularly, high levels of suspended particulate matter (PM) were observed during winter, when the northeasterly monsoon prevails. For example, concentrations of wintertime PM10 (particles ≤ 10 mm in diameter) frequently exceeded 100 mg/m3 in the last three years. In addition to the air‐quality data analysis, aerosol samples were collected between 22 November 2007 and 6 March 2008 and subjected to chemical analyses of various species. Our findings show that the three principal PM components include organic, mineral, and sulfate species with moderate to minor fractions of nitrate, sea salt, elemental carbon, and trace metal oxides. The high PM levels observed over the island may be partly attributed to the transport from a mixed‐type industrial area located ∼40 km northeast of Kinmen. Our study could partially fill the air quality data gap between the YRD and PRD regions, and highlight the alarming fact that air pollution has gradually expanded along eastern China’s coastal zone

Risk factors for exacerbations and pneumonia in patients with chronic obstructive pulmonary disease: a pooled analysis.

BACKGROUND: Patients with chronic obstructive pulmonary disease (COPD) are at risk of exacerbations and pneumonia; how the risk factors interact is unclear. METHODS: This post-hoc, pooled analysis included studies of COPD patients treated with inhaled corticosteroid (ICS)/long-acting β2 agonist (LABA) combinations and comparator arms of ICS, LABA, and/or placebo. Backward elimination via Cox's proportional hazards regression modelling evaluated which combination of risk factors best predicts time to first (a) pneumonia, and (b) moderate/severe COPD exacerbation. RESULTS: Five studies contributed: NCT01009463, NCT01017952, NCT00144911, NCT00115492, and NCT00268216. Low body mass index (BMI), exacerbation history, worsening lung function (Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage), and ICS treatment were identified as factors increasing pneumonia risk. BMI was the only pneumonia risk factor influenced by ICS treatment, with ICS further increasing risk for those with BMI <25 kg/m2. The modelled probability of pneumonia varied between 3 and 12% during the first year. Higher exacerbation risk was associated with a history of exacerbations, poorer lung function (GOLD stage), female sex and absence of ICS treatment. The influence of the other exacerbation risk factors was not modified by ICS treatment. Modelled probabilities of an exacerbation varied between 31 and 82% during the first year. CONCLUSIONS: The probability of an exacerbation was considerably higher than for pneumonia. ICS reduced exacerbations but did not influence the effect of risks associated with prior exacerbation history, GOLD stage, or female sex. The only identified risk factor for ICS-induced pneumonia was BMI <25 kg/m2. Analyses of this type may help the development of COPD risk equations