Application of tuned liquid dampers in controlling the torsional vibration of high rise buildings

Ross, Andrew S.,El Damatty, Ashraf A.,El Ansary, Ayman M. Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.21 No.5

Excessive motions in buildings cause occupants to become uncomfortable and nervous. This is particularly detrimental to the tenants and ultimately the owner of the building, with respect to financial considerations. Serviceability issues, such as excessive accelerations and inter-story drifts, are more prevalent today due to advancements in the structural systems, strength of materials, and design practices. These factors allow buildings to be taller, lighter, and more flexible, thereby exacerbating the impact of dynamic responses. There is a growing need for innovative and effective techniques to reduce the serviceability responses of these tall buildings. The current study considers a case study of a real building to show the effectiveness and robustness of the TLD in reducing the coupled lateral-torsional motion of this high-rise building under wind loading. Three unique multi-modal TLD systems are designed specifically to mitigate the torsional response of the building. A procedure is developed to analyze a structure-TLD system using High Frequency Force Balance (HFFB) test data from the Boundary Layer Wind Tunnel Laboratory (BLWTL) at the University of Western Ontario. The effectiveness of the unique TLD systems is investigated. In addition, a parametric study is conducted to determine the robustness of the systems in reducing the serviceability responses. Three practical parameters are varied to investigate the robustness of the TLD system: the height of water inside the tanks, the amplitude modification factor, and the structural modal frequencies.

Application of tuned liquid dampers in controlling the torsional vibration of high rise buildings

Andrew S. Ross,Ashraf A. El Damatty,Ayman M. El Ansary 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.21 No.5

Excessive motions in buildings cause occupants to become uncomfortable and nervous. This is particularly detrimental to the tenants and ultimately the owner of the building, with respect to financial considerations. Serviceability issues, such as excessive accelerations and inter-story drifts, are more prevalent today due to advancements in the structural systems, strength of materials, and design practices. These factors allow buildings to be taller, lighter, and more flexible, thereby exacerbating the impact of dynamic responses. There is a growing need for innovative and effective techniques to reduce the serviceability responses of these tall buildings. The current study considers a case study of a real building to show the effectiveness and robustness of the TLD in reducing the coupled lateral-torsional motion of this high-rise building under wind loading. Three unique multi-modal TLD systems are designed specifically to mitigate the torsional response of the building. A procedure is developed to analyze a structure-TLD system using High Frequency Force Balance (HFFB) test data from the Boundary Layer Wind Tunnel Laboratory (BLWTL) at the University of Western Ontario. The effectiveness of the unique TLD systems is investigated. In addition, a parametric study is conducted to determine the robustness of the systems in reducing the serviceability responses. Three practical parameters are varied to investigate the robustness of the TLD system: the height of water inside the tanks, the amplitude modification factor, and the structural modal frequencies.

A new physical interpretation of optical and infrared variability in quasars

Ross, Nicholas P,Ford, K E Saavik,Graham, Matthew,McKernan, Barry,Stern, Daniel,Meisner, Aaron M,Assef, Roberto J,Dey, Arjun,Drake, Andrew J,Jun, Hyunsung D,Lang, Dustin Oxford University Press 2018 MONTHLY NOTICES- ROYAL ASTRONOMICAL SOCIETY Vol.480 No.4

Sprint interval training on the vertical treadmill improves aerobic and anaerobic running performance

Alastair Ross Jordan,David Claxton,Alison Purvis,Andrew Barnes,Mary Fysh 한국운동재활학회 2018 JER Vol.14 No.1

The vertical treadmill (VertiRun) is an unresearched mode of exercise where users engage in a “running-like” action whilst body weight is supported by a recumbent bench and overhanging resistance cables are tethered to the user’s ankles. The purpose of this study was to de-termine the effects of training on a VertiRun and any cross-training ef-fect on running performance. Thirty active males (age, 22±4 years; stature, 1.79±0.08 m; body mass, 78.5±12.6 kg) volunteered for this study. Participants’ aerobic and anaerobic running performance were deter-mined by incremental maximum rate of oxygen consumption (VO2max) treadmill test and a maximum anaerobic running test (MART), respec-tively. Participants were matched and then randomly assigned to either a VertiRun group, 20-m shuttle sprint group or control group. The inter-vention consisted of 4–6, 30-sec all-out efforts with 4-min recovery be-tween bouts, 3 days a week for 6 weeks. The pre- and postintervention VO2max and MART were analysed using a mixed repeated measures analysis of variance. MART increased by 4.5% in the VertiRun group (P=0.006) and 4% in the sprint group (P<0.001). VO2max increased by 6.2% in the VertiRun group (P=0.009) and 5.5% in the sprint group (P=0.020). The MART and VO2max of the control group were unchanged (P=0.910 and P=0.915, respectively). These data suggest that the Ver-tiRun could be an effective cross-training mode for running and could supplement training programmes. Also, as VertiRun is a low-impact ex-ercise it might be useful in the physical preparation of athletes returning to sport following lower limb injury.

Incidence and Significance of Biliary Stricture in Chronic Pancreatitis Patients Undergoing Extracorporeal Shock Wave Lithotripsy for Obstructing Pancreatic Duct Stones

( Jong Jin Hyun ),( Shayan S. Irani ),( Andrew S. Ross ),( Michael C. Larsen ),( Michael Gluck ),( Richard A. Kozarek ) 대한소화기학회 2021 Gut and Liver Vol.15 No.1

Background/Aims: This study assessed the significance of biliary stricture in symptomatic chronic pancreatitis patients requiring extracorporeal shock wave lithotripsy (ESWL) and endoscopic retrograde cholangiopancreatography (ERCP) to remove obstructing pancreatic calculi. Methods: A total of 97 patients underwent ESWL followed by ERCP to remove pancreatic calculi between October 2014 and October 2017 at Virginia Mason Medical Center. Significant biliary stricture (SBS) was defined as a stricture with upstream dilation on computed tomography scan or magnetic resonance cholangiopancreatography scans accompanied by cholestasis and/or cholangitis. SBS was initially managed by either a plastic stent or fully covered self-expandable metallic stent (fcSEMS). If the stricture did not resolve, the stent was replaced with either multiple plastic stents or another fcSEMS. Data were collected by retrospectively reviewing the medical records. Results: Biliary strictures were noted in approximately one-third of patients (34/97, 35%) undergoing ESWL for pancreatic calculi. Approximately one-third of the biliary strictures (11/34, 32%) were SBS. Pseudocysts were more frequently found in those with SBS (36% vs 8%, p=0.02), and all pseudocysts in the SBS group were located in the pancreatic head. The initial stricture resolution rates with fcSEMSs and plastic prostheses were 75% and 29%, respectively. The overall success rate for stricture resolution was 73% (8/11), and the recurrence rate after initial stricture resolution was 25% (2/8). Conclusions: Although periductal fibrosis is the main mechanism underlying biliary stricture development in chronic pancreatitis, inflammation induced by obstructing pancreatic calculi, including pseudocysts, is an important contributing factor to SBS formation during the acute phase. (Gut Liver 2021;15:128-134)

Outcomes of Infected versus Symptomatic Sterile Walled-Off Pancreatic Necrosis Treated with a Minimally Invasive Therapy

( Jong Jin Hyun ),( Nadav Sahar ),( Anand Singla ),( Andrew S Ross ),( Shayan S Irani ),( S Ian Gan ),( Michael C Larsen ),( Richard A Kozare ),( Michael Gluck ) 대한소화기학회 2019 Gut and Liver Vol.13 No.2

Background/Aims: Acute pancreatitis complicated by walled-off necrosis (WON) is associated with high morbidity and mortality, and if infected, typically necessitates intervention. Clinical outcomes of infected WON have been described as poorer than those of symptomatic sterile WON. With the evolution of minimally invasive therapy, we sought to compare outcomes of infected to symptomatic sterile WON. Methods: We performed a retrospective cohort study examining patients who were undergoing dual-modality drainage as minimally invasive therapy for WON at a high-volume tertiary pancreatic center. The main outcome measures included mortality with a drain in place, length of hospital stay, admission to intensive care unit, and development of pancreatic fistulae. Results: Of the 211 patients in our analysis, 98 had infected WON. The overall mortality rate was 2.4%. Patients with infected WON trended toward higher mortality although not statistically significant (4.1% vs 0.9%, p=0.19). Patients with infected WON had longer length of hospitalization (29.8 days vs 17.3 days, p<0.01), and developed more spontaneous pancreatic fistulae (23.5% vs 7.8%, p<0.01). Multivariate analysis showed that infected WON was associated with higher odds of spontaneous pancreatic fistula formation (odds ratio, 2.65; 95% confidence interval, 1.20 to 5.85). Conclusions: This study confirms that infected WON has worse outcomes than sterile WON but also demonstrates that WON, once considered a significant cause of death, can be treated with good outcomes using minimally invasive therapy. (Gut Liver 2019;13:215-222)

Double Balloon Enteroscopy in a North American Setting: A Large Single Center 5-year Experience

( Gulseren Seven ),( Richard A. Kozarek ),( Andrew Ross ),( Shayan Irani ),( Michael Gluck ),( Drew Schembre ),( Johannes Koch ),( S. Ian Gan ) 대한장연구학회 2013 Intestinal Research Vol.11 No.1

Background/Aims: Double balloon enteroscopy (DBE) allows both diagnosis and therapeutic maneuvers in the small bowel. Its use was pioneered in Europe and Asia but there remains a relative paucity of literature from North America. Our aim in this study was to determine diagnostic and therapeutic yield in a North American setting. Methods: A five-year retrospective analysis of all patients undergoing DBE at a single tertiary care North American hospital was performed. Results: Four-hundred fifty-seven procedures, 265 anterograde and 192 retrograde, were performed on 335 patients. The most common indications were obscure gastrointestinal bleeding, small bowel obstruction, and suspected masses and mucosal abnormalities. Total enteroscopy was achieved in 19 of the 89 patients who had both anterograde and retrograde procedures. Overall diagnostic yield in the determination of cause of symptoms or previous imaging was 52%. The most common causes of obscure bleeding were small bowel ulcers (10%), vascular lesions (25%) and neoplasms (10%). The most common causes of small bowel obstruction were strictures, some of which underwent dilation. Other therapeutic interventions included polypectomy, retrieval of retained capsules, stent retrievals and percutaneous enteral jejunostomy tube placement. Overall complication rates were very low (0.6%) and included medication reaction (n=1), scope dysfunction (n=1) and perforation (n=1). Conclusions: DBE can be performed safely and with good diagnostic yield in a single referral center in North America. (Intest Res 2013;11:34-40)

Molecular Origins of the High-Performance Nonlinear Optical Susceptibility in a Phenolic Polyene Chromophore: Electron Density Distributions, Hydrogen Bonding, and ab Initio Calculations

Lin, Tze-Chia,Cole, Jacqueline M.,Higginbotham, Andrew P.,Edwards, Alison J.,Piltz, Ross O.,Pé,rez-Moreno, Javier,Seo, Ji-Youn,Lee, Seung-Chul,Clays, Koen,Kwon, O-Pil American Chemical Society 2013 JOURNAL OF PHYSICAL CHEMISTRY C - Vol.117 No.18

<P>The molecular and supramolecular origins of the superior nonlinear optical (NLO) properties observed in the organic phenolic triene material, OH1 (2-(3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene)malononitrile), are presented. The molecular charge-transfer distribution is topographically mapped, demonstrating that a uniformly delocalized passive electronic medium facilitates the charge-transfer between the phenolic electron donor and the cyano electron acceptors which lie at opposite ends of the molecule. Its ability to act as a “push–pull” π-conjugated molecule is quantified, relative to similar materials, by supporting empirical calculations; these include bond-length alternation and harmonic-oscillator stabilization energy (HOSE) tests. Such tests, together with frontier molecular orbital considerations, reveal that OH1 can exist readily in its aromatic (neutral) or quinoidal (charge-separated) state, thereby overcoming the “nonlinearity-thermal stability trade-off”. The HOSE calculation also reveals a correlation between the quinoidal resonance contribution to the overall structure of OH1 and the UV–vis absorption peak wavelength in the wider family of configurationally locked polyene framework materials. Solid-state tensorial coefficients of the molecular dipole, polarizability, and the first hyperpolarizability for OH1 are derived from the first-, second-, and third-order electronic moments of the experimental charge-density distribution. The overall solid-state molecular dipole moment is compared with those from gas-phase calculations, revealing that crystal field effects are very significant in OH1. The solid-state hyperpolarizability derived from this charge-density study affords good agreement with gas-phase calculations as well as optical measurements based on hyper-Rayleigh scattering (HRS) and electric-field-induced second harmonic (EFISH) generation. This lends support to the further use of charge-density studies to calculate solid-state hyperpolarizability coefficients in other organic NLO materials. Finally, this charge-density study is also employed to provide an advanced classification of hydrogen bonds in OH1, which requires more stringent criteria than those from conventional structure analysis. As a result, only the strongest OH···NC interaction is so classified as a true hydrogen bond. Indeed, it is this electrostatic interaction that influences the molecular charge transfer: the other four, weaker, nonbonded contacts nonetheless affect the crystal packing. Overall, the establishment of these structure–property relationships lays a blueprint for designing further, more NLO efficient, materials in this industrially leading organic family of compounds.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2013/jpccck.2013.117.issue-18/jp400648q/production/images/medium/jp-2013-00648q_0007.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/jp400648q'>ACS Electronic Supporting Info</A></P>

A quasi-3D model of the whole lung: airway extension to the tracheobronchial limit using the constrained constructive optimization and alveolar modeling, using a sac–trumpet model

Ravishekar (Ravi) Kannan,Narender Singh,Andrzej Przekwas,Xianlian Alex Zhou,Ross Walenga,Andrew Babiskin 한국CDE학회 2021 Journal of computational design and engineering Vol.8 No.2

Existing computational models used for simulating the flow and species transport in the human airways are zero-dimensional (0D) compartmental, three-dimensional (3D) computational fluid dynamics (CFD), or the recently developed quasi-3D (Q3D) models. Unlike compartmental models, the full CFD and Q3D models are physiologically and anatomically consistent in the mouth and the upper airways, since the starting point of these models is the mouth–lung surface geometry, typically created from computed tomography (CT) scans. However, the current resolution of CT scans limits the airway detection between the 3rd–4th and 7th–9th generations. Consequently, CFD and the Q3D models developed using these scans are generally limited to these generations. In this study, we developed a method to extend the conducting airways from the end of the truncated Q3D lung to the tracheobronchial (TB) limit. We grew the lung generations within the closed lung lobes using the modified constrained constructive optimization, creating an aerodynamically optimized network aiming to produce equal pressure at the distal ends of the terminal segments. This resulted in a TB volume and lateral area of ∼165 cc and ∼2000 cm2, respectively. We created a “sac–trumpet” model at each of the TB outlets to represent the alveoli. The volumes of the airways and the individual alveolar generations match the anatomical values by design: with the functional residual capacity at 2611 cc. Lateral surface areas were scaled to match the physiological values. These generated Q3D whole lung models can be efficiently used for conducting multiple breathing cycles of drug transport and deposition simulations.

Can We Prevent Resistance to Osimertinib? Combination or Sequential

Kim, Min Hwan,Lim, Sun Min,Lee, Kwangho,Soo, Ross Andrew,Cho, Byoung Chul Elsevier 2018 JOURNAL OF THORACIC ONCOLOGY Vol.13 No.7