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Development and Evaluation of a Novel Inclusion Seeding Methodology for Ti-6Al-4V Castings
( Paul L. Ret ),( Jerald R. Brevick ),( Yong K. Park ) 대한금속재료학회 ( 구 대한금속학회 ) 2007 METALS AND MATERIALS International Vol.13 No.4
Hard alpha inclusions in titanium (Ti) investment castings are generally known to have detrimental effects on the mechanical properties of these castings. However, actual inclusions are infrequent and occur in random locations in castings. As a result, it is difficult to obtain tensile or fatigue test specimens of titanium castings with inclusions in the gage section. Quantifying the adverse influence of inclusions on the mechanical properties of castings is, therefore, extremely challenging. To address this problem, a novel artificial inclusion seeding methodology was developed to emulate actual Ti investment casting inclusions. Prefabricated inclusions were seeded into machined holes in cast Ti-6Al-4V plates, the holes were back-filled with plugs of the same Ti alloy and were then electron-beam (EB) welded closed. Hot isostatic pressing (HIP) was utilized to incorporate the inclusions fully into the cast titanium material. Finally, the plates were machined to create mechanical test specimens with inclusions centered in the gage region. Test specimens created by means of this novel artificial seeding methodology were evaluated and found to be equivalent to Ti casting specimens containing actual cast-in inclusions.
Advancd Treatment by Biological Processes - Biological Nutrient Removal
( Paul F . Greenfield,Kin Man Ho,Linda L . Blackall,Peter R . F . Bell,Andre Krol ) 한국물환경학회 1994 한국물환경학회지 Vol.10 No.3
Biological phosphorus and nitrogen removal and related sludge bulking control in both intermittent cyclic and continuous activated sludge systems are assessed. Experimental results from a laboratory-scale investigation using fermented domestic sewage indicated the advantages of achieving high levels of P ana N removal and good sludge-settling properties using the intermittent cyclic process, as compared to the space-oriented operation of a continuous facility. Accordingly, this cost-effective, simple and reliable technology is receiving wide acceptance as an appropriate technology for not only small treatment applications but in creasingly for large installations. The modified intermittently fed and decanted system incorporating non-mixing sequences produced an effluent quality of NO₃-N$lt;5 ㎎/ℓ, PO₄-P$lt; 1 ㎎/ℓ and NH₃-N$lt;2 ㎎/ℓ, with a nonbulking sludge having a sludge volume index $lt; 120 ㎖/g, despite unfavourable influent characteristics (TCOD:TKN $lt; 7, TKN$gt; 60㎎/ℓ, TP - 7 - 10 ㎎/ℓ and RBCOD $lt;30㎎/ℓ). In contrast, the modified 4-stage Bar-denpho process could not achieve an effluent PO₄-P concentration of $lt; 1 ㎎/ℓ The effluent NO₃-N concentration and sludge volume index (SVI) were always high and occasionally reached 16 ㎎/ℓ and 422 ㎖/g, respectively. The causative filaments were identified to be the low F:M growers - Types 0041/0675.
No retreat from the heat: temperature-related risk of violent assault is increased by being inside
Heather R. Stevens,Petra L. Graham,Paul J. Beggs,Ivan C. Hanigan 서울시립대학교 도시과학연구원 2024 도시과학국제저널 Vol.28 No.1
Studies finding an association between increasing temperature and violent crime have largely overlooked the potential effect modification of crime location. This study analysed 13 years of reported violent crime to investigate if there is a relationship between daily ambient temperature and crime type (domestic, non-domestic and sexual assault), and how this differs by whether the crime occurred inside or out. We found that predicted daily counts of domestic violence increased with temperature, and this association was greater for locations inside. Non-domestic assaults also increased with higher temperature, however when compared by location the incidents that occurred outside rose to around 30°C then plateaued while inside the risk continued to rise. Sexual assault peaked and then declined at around 30°C in inside and outside locations. The findings support the development of prevention and preparedness strategies by considering how the complex drivers behind the temperature–aggression association are modified by the location where it occurred.
N(<sup>2</sup>D) Product Velocity Mapped Imaging in the VUV Photolysis of Nitrous Oxide at 118.2 nm
Cosofret, Bogdan R.,Lambert, H. Mark,Houston, Paul L. Korean Chemical Society 2002 Bulletin of the Korean Chemical Society Vol.23 No.2
Resonance-enhanced multiphoton ionization with time-of-flight product imaging of the $N(^2D)$ atoms has been used to study the $N_2O$ photodissociation at 118.2 nm and the two-photon dissociation at 268.9 nm. These imaging experiments allowed the determination of the total kinetic energy distribution of the $NO(X^2{\prod})$ and $N(^2D_{5/2})$ products. The $NO(X^2{\prod})$ fragments resulting from the photodissociation processes are produced in highly vibrationally excited states. The two-photon photodissociation process yields a broad $NO(X^2{\prod})$ vibrational energy distribution, while the 118.2 nm dissociation appears to produce a vibrational distribution sharply peaked at $NO(X^2{\prod},\;{\nu}=14)$.
DeBono Nathan L.,Daniels Robert D.,Beane Freeman Laura E.,Graber Judith M.,Hansen Johnni,Teras Lauren R.,Driscoll Tim,Kjaerheim Kristina,Demers Paul A.,Glass Deborah C.,Kriebel David,Kirkham Tracy L. 한국산업안전보건공단 산업안전보건연구원 2023 Safety and health at work Vol.14 No.2
Objective: We performed a meta-analysis of epidemiological results for the association between occupational exposure as a firefighter and cancer as part of the broader evidence synthesis work of the IARC Monographs program. Methods: A systematic literature search was conducted to identify cohort studies of firefighters followed for cancer incidence and mortality. Studies were evaluated for the influence of key biases on results. Random-effects meta-analysis models were used to estimate the association between ever-employment and duration of employment as a firefighter and risk of 12 selected cancers. The impact of bias was explored in sensitivity analyses. Results: Among the 16 included cancer incidence studies, the estimated meta-rate ratio, 95% confidence interval (CI), and heterogeneity statistic (I2) for ever-employment as a career firefighter compared mostly to general populations were 1.58 (1.14–2.20, 8%) for mesothelioma, 1.16 (1.08–1.26, 0%) for bladder cancer, 1.21 (1.12–1.32, 81%) for prostate cancer, 1.37 (1.03–1.82, 56%) for testicular cancer, 1.19 (1.07–1.32, 37%) for colon cancer, 1.36 (1.15–1.62, 83%) for melanoma, 1.12 (1.01–1.25, 0%) for non-Hodgkin lymphoma, 1.28 (1.02–1.61, 40%) for thyroid cancer, and 1.09 (0.92–1.29, 55%) for kidney cancer. Ever-employment as a firefighter was not positively associated with lung, nervous system, or stomach cancer. Results for mesothelioma and bladder cancer exhibited low heterogeneity and were largely robust across sensitivity analyses. Conclusions: There is epidemiological evidence to support a causal relationship between occupational exposure as a firefighter and certain cancers. Challenges persist in the body of evidence related to the quality of exposure assessment, confounding, and medical surveillance bias.
SLIDERS FOR THE NEXT GENERATION MAGNETIC HARD DISK DRIVE SYSTEMS - NUMERICAL SIMULATION
Myung S. Jhon,Paul R. Peck,Soo-Choon Kang,Benjamin L. Wang,In-Eung Kim,Ki-Ook Park 한국자기학회 1995 韓國磁氣學會誌 Vol.5 No.5
Fundamental issues and general procedures of modeling the head disk interface (HDI) in order to provide design criteria for future ultra-low flying sliders are given. Intermittent contact and gaseous rarefaction effects are discussed using nonconventional kinetic theory. To illustrate the simulation results, we modeled IBM 3370 taper flat sliders and positive/negative bow tie sliders. Several alternative HDI concepts for future disk drives - viscoelastic bearings, a hybrid system, and contact recording - are also briefly discussed.
Choi, Man Ho,Skipper, Paul L,Wishnok, John S,Tannenbaum, Steven R American Society for Pharmacology and Experimental 2005 Drug metabolism and disposition: the biological fa Vol.33 No.6
<P>A combination of accelerator mass spectrometry (AMS) and liquid chromatography-tandem mass spectrometry has been used to clarify some new aspects of testosterone metabolism. The main pathway of testosterone oxidative metabolism by human liver microsomes is the formation of 1beta-, 2alpha-/beta-, 6beta-, 15beta-, and 16beta-hydroxytestosterones, mainly catalyzed by cytochromes P450 2C9, 2C19, and 3A4. We now report the first determination that 11beta-hydroxytestosterone (11beta-OHT) can also be formed by human liver microsomal fractions. The structures of five hydroxylated metabolites of testosterone (2beta-, 6beta-, 11beta-, 15beta-, and 16beta-OHT) and the C-17 oxidative metabolite androstenedione were determined by liquid chromatography with UV detection at 240 nm and liquid chromatography-tandem mass spectrometry. Corresponding results were obtained by high-performance liquid chromatography-AMS analysis of incubations of [4-14C]testosterone with human liver microsomes. 6beta-Hydroxylation was always the dominant metabolic pathway, but 2beta-, 15beta-, and 16beta-OHT, and androstenedione were also formed. The previously undetected hydroxytestosterone, 11beta-OHT, was found to be a minor metabolite formed by human liver microsomal enzymes. It was formed more readily by CYP3A4 than by either CYP2C9 or CYP2C19. 11beta-Hydroxylation was inhibited by ketoconazole (IC50 = 30 nM) at concentrations similar to the IC50 (36 nM) for 6beta-hydroxylation Therefore, CYP3A4 could be mainly responsible for testosterone 11beta-hydroxylation in the human liver. These findings identify human hepatic biotransformation of testosterone to 11beta-OHT as a previously unrecognized extra-adrenal metabolic pathway.</P>
Background Surface Estimation for Reverse Engineering of Reliefs
Liu, Shenglan,Martin, Ralph R.,Langbein, Frank C.,Rosin, Paul L. Society for Computational Design and Engineering 2007 International Journal of CAD/CAM Vol.7 No.1
Reverse engineering of reliefs aims to turn an existing relief superimposed on an underlying surface into a geometric model which may be applied to a different base surface. Steps in this process include segmenting the relief from the background, and describing it as an offset height field relative to the underlying surface. We have previously considered relief segmentation using a geometric snake. Here, we show how to use this initial segmentation to estimate the background surface lying under the relief, which can be used (i) to refine the segmentation and (ii) to express the relief as an offset field. Our approach fits a B-spline surface patch to the measured background data surrounding the relief, while tension terms ensure this background surface smoothly continues underneath the relief where there are no measured background data points to fit. After making an initial estimate of relief offset height everywhere within the patch, we use a support vector machine to refine the segmentation. Tests demonstrate that this approach can accurately model the background surface where it underlies the relief, providing more accurate segmentation, as well as relief height field estimation. In particular, this approach provides significant improvements for relief concavities with narrow mouths and can segment reliefs with small internal holes.