A three-dimensional simulation of transition and early turbulence in a time-developing mixing layer

The physics of the transition and early turbulence regimes in the time developing mixing layer was investigated. The sensitivity of the mixing layer to the disturbance field of the initial condition is considered. The growth of the momentum thickness, the mean velocity profile, the turbulence kinetic energy, the Reynolds stresses, the anisotropy tensor, and particle track pictures of computations are all examined in an effort to better understand the physics of these regimes. The amplitude, spectrum shape, and random phases of the initial disturbance field were varied. A scheme of generating discrete orthogonal function expansions on some nonuniform grids was developed. All cases address the early or near field of the mixing layer. The most significant result shows that the secondary instability of the mixing layer is produced by spanwise variations in the straining field of the primary vortex structures

Image motion compensation for an electronic imaging system

The design of an image compensation device is given which is capable of minimizing the in-track image disturbances caused by velocity variations in an optical scanning device. Guidelines for the development of this mechanism are based on known optical principles. Acceptable response capabilities for this device are based on subjective and quantitative image quality standards. A first order analysis of the device was conducted to specify the performance required to minimize the distortions mentioned above. The final system specifications take into account actual hardware that is currently available for the typical scanner system presented

Research study for determination of liquid surface profile in a cryogenic tank during gas injection Quarterly progress report no. 9, Jun. 18 - Sep. 17, 1966

Determining liquid surface profiles in cryogenic tank during gas injectio

Cyclin F Is Degraded during G2-M by Mechanisms Fundamentally Different from Other Cyclins

Cyclin F, a cyclin that can form SCF complexes and bind to cyclin B, oscillates in the cell cycle with a pattern similar to cyclin A and cyclin B. Ectopic expression of cyclin F arrests the cell cycle in G2/M. How the level of cyclin F is regulated during the cell cycle is completely obscure. Here we show that, similar to cyclin A, cyclin F is degraded when the spindle assembly checkpoint is activated and accumulates when the DNA damage checkpoint is activated. Cyclin F is a very unstable protein throughout much of the cell cycle. Unlike other cyclins, degradation of cyclin F is independent of ubiquitination and proteasome-mediated pathways. Interestingly, proteolysis of cyclin F is likely to involve metalloproteases. Rapid destruction of cyclin F does not require the N-terminal F-box motif but requires the COOH-terminal PEST sequences. The PEST region alone is sufficient to interfere with the degradation of cyclin F and confer instability when fused to cyclin A. These data show that although cyclin F is degraded at similar time as the mitotic cyclins, the underlying mechanisms are entirely distinct

Automated transition state theory calculations for high-throughput kinetics

A scarcity of known chemical kinetic parameters leads to the use of many reaction rate estimates, which are not always sufficiently accurate, in the construction of detailed kinetic models. To reduce the reliance on these estimates and improve the accuracy of predictive kinetic models, we have developed a high-throughput, fully automated, reaction rate calculation method, AutoTST. The algorithm integrates automated saddle-point geometry search methods and a canonical transition state theory kinetics calculator. The automatically calculated reaction rates compare favorably to existing estimated rates. Comparison against high level theoretical calculations show the new automated method performs better than rate estimates when the estimate is made by a poor analogy. The method will improve by accounting for internal rotor contributions and by improving methods to determine molecular symmetry.Comment: 29 pages, 8 figure

Cost-effectiveness analysis of the management of distal ureteral stones in children

Objective To determine the most cost-effective approach to the management of distal ureteral stones in children given the potential for recurrent renal colic during a trial of passage versus potential stent discomfort and complications of ureteroscopy. Methods We developed a decision tree to project costs and clinical outcomes associated with observation, medical explusive therapy (MET), and ureteroscopy for the management of an index patient with a 4mm distal ureteral stone. We determined which strategy would be least costly and offer the most pain-free days within 30 days of diagnosis. We performed a one-way sensitivity analysis on the probability of successful stone passage with MET. We obtained probabilities from the literature and costs from the 2016 Pediatric Health Information System Database. Results Ureteroscopywas the costliest strategy but maximized the number of pain-free days within 30 days of diagnosis ($5,282/29 pain-free days). MET was less costly than ureteroscopybut also less effective ($615/21.8 pain-free days). Observation cost more than MET and was also less effective ($2,139/15.5 pain-free days). The one-way sensitivity analysis on the probability of successful stone passage with MET demonstrated that ureteroscopyalways has the highest net monetary benefits value and is therefore the recommended strategy given a fixed WTP. Discussion Using a rigorous decision-science approach, we found that ureteroscopy is the recommended strategy in children with small distal ureteral stones. Although it cost more than MET, it resulted in more pain-free days in the first 30 days following diagnosis given the faster resolution of the stone episode

Roadway Incident Emergency Response: Workshop Summary and Detour Maps

Delays associated with incidents and accidents on heavily traveled highways have been recognized as a major inconvenience and a burden on the driving public. Heavy traffic volumes on interstates in Kentucky result in significantly increased probability for delay occurrences. When there is an occurrence which disrupts traffic, the adverse effects are widespread. High volumes of trucks use the north-south corridors in the state and delays can produce significant costs to both shippers and users of products being shipped. Many efforts are underway to address the problems associated with congestion; including improved traffic management techniques and applications of advanced technology. A primary clement of emergency response is the level of communication and coordination when an incident occurs. Considerable attention has been given to the needs of improved interaction between the responsible agencies when there is an incident or accident requiring coordinated response. At-scene coordination can be a positive aspect of emergency response when a comprehensive plan is in place to address the lines of authority and procedures for responding to the emergency. The objectives of this project were the following: 1) to develop and implement an emergency response management review process to document currently used procedures in Kentucky: 2) to recommend alternative procedures for emergency response which focus on the need to improve accident investigation and clearance processes; 3) to identify the responsible agencies and personnel in the line of authority for emergency response; 4) to develop and present workshops for emergency response personnel related to prompt clearance of accident/incident scenes; and 5) to develop a set of detour maps for interstates and parkways. including a directory of emergency response personnel

Reply to discussion by G. Carosi and H. Chanson on "Turbulence characteristics in skimming flows on stepped spillways"

A main technical issue seems to be associated with the structure of the two-phase air–water flow skimming over the pseudo-bottom formed by the step edges. This is a difficult topic. In the air–water skimming flow, the microscopic structure of the gas–liquid mixture is closely linked with the interactions between turbulent vortices and air–water entities (bubbles, droplets, packets) (e.g., Chanson and Toombes 2002; Carosi and Chanson 2008; Gonzalez and Chanson 2008). In the high-velocity free-surface flow, the strong interactions between the turbulent waters and the atmosphere lead to a complete deformation at the interface. Through the free-surface, air is continuously trapped, and the resulting air–water mixture extends through the entire flow (Rao and Kobus 1971; Wood 1991; Chanson 1997). The air–water flow is characterized a complicated two-phase turbulent motion with void fractions ranging from some small, often nonzero values close to the invert to 100% above a pseudo "free-surface" that is usually defined as the location where the void fraction equals 90% (Cain and Wood 1981; Wood 1991; Chanson 1997; Matos 2000). The notion of "effective homogenous flow" contradicts detailed measurements conducted with accurate instrumentations in large-size facilities with well-controlled flow conditions and it is obsolete. Recent findings (Carosi and Chanson 2008) demonstrated in fact a marked changed in flow properties for C ~ 0.95 to 0.97, that is consistent with earlier studies suggesting the use of Y95 or even Y98 as the characteristic air–water flow thickness (Jevdjevich and Levin 1953; Aivazyan 1986)