Practical Aspects of Propulsion Shaft Alignment

2021 ◽  
Author(s):  
Kyriakos Avgouleas ◽  
Emmanouil Sarris ◽  
George Gougoulidis
Keyword(s):  
Cost Effectiveness ◽  
Numerical Model ◽  
High Speed ◽  
The Other ◽  
Technical Literature ◽  
Trade Off ◽  
Fea Model ◽  
Shaft Alignment ◽  
Alignment Strategy ◽  
Potential Damage

The economical and operational implications of poor alignment are indisputable for the propulsion shafting system of a commercial vessel. This holds true for naval vessels as well, although far less documented in the technical literature. This paper addresses some of the challenges associated with the proper alignment of a high-speed naval craft, which has been in service for many years. Laser bore-sighting was performed on a Guided Missile Fast Patrol Boat resting on a docking cradle. The measured bearing offsets were input to a FEA model of the shafting system to calculate bearing reactions and detect potential misalignment issues. Subsequent decisions regarding corrective measures take into account the results computed by the numerical model, experience from sister ships, the available documentation from the building yard and several other factors which are discussed in the paper. The solutions proposed are targeted towards a balanced trade-off between cost effectiveness and out-of-service time on one hand, and the risk of potential damage from misalignment on the other hand, which would seriously disrupt the ship’s operational availability. Practical aspects and lessons identified in the process are also presented, which demonstrate the distinct differences in alignment strategy of a high-speed naval craft compared to a typical commercial vessel.

Parameterized Design of a Supersonic Radome

2001 ◽  
Author(s):  
Michael S. L. Hollis
Keyword(s):  
High Speed ◽  
Extensive Study ◽  
The Other ◽  
Short Term ◽  
Trade Off ◽  
Aerodynamic Shape ◽  
Parameterized Design ◽  
Ballistic Projectiles ◽  
Mach Numbers ◽  
Antenna Location

Abstract Future gun-launched projectiles will have higher muzzle velocities. There currently exists a need for RF transparent radome solutions with muzzle velocities near Mach numbers equal to 3 (M = 3). Future Combat System (FCS) requirements may push these velocities as high as M = 5. Assessments of aerothermal heating requirements for specific radome geometries need to be studied. Trade-off studies involving aerodynamic shape, antenna location, materials, and RF characteristics also need to be made. The final product of this report is twofold. The first is a short-term solution using the extruded/molded plastics to manufacture a radome. The other is a guideline for a more extensive study to find several solutions for high speed, RF transparent radomes for ballistic projectiles.

Effect of initial pressure of oblique-blowing airflow and folding-in airflow on yarn tucked-in in the pneumatic tucked-in selvedge apparatus

2021 ◽  
pp. 004051752110134
Author(s):  
Yisheng Liu ◽  
Xinlei Zhou ◽  
Xiaoying Cheng ◽  
Dandan Liu
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Laboratory Experiments ◽  
Initial Pressure ◽  
The Other ◽  
High Speed Camera ◽  
Simulation Data ◽  
Structure Interaction ◽  
Airflow Field ◽  
The One

In this paper, numerical simulation and laboratory experiments were combined to research the tucked-in behavior of the yarn in the pneumatic tucked-in selvedge apparatus, and explore the effect of initial pressure of oblique-blowing airflow and folding-in airflow on yarn tucked-in. This work focused on the motion of a single yarn of which one end was fixed while the other was free. Initial pressures for oblique-blowing airflow and folding-in airflow were set as parameters. A numerical model was developed to simulate the process based on the one-way fluid–structure interaction. Then a laboratory experiment was carried out with the help of a high-speed camera to record the motion behaviors of yarns. The motions were compared with the simulation data and showed that the proposed numerical model can properly replicate the motion of yarn and its points in the airflow field. Each group of yarns with different initial pressures was able to be tucked-in and had an elongation. Increasing the initial pressures of oblique-blowing airflow from 0.3 MPa to 0.4 MPa and folding-in airflow from 0.35 MPa to 0.4MPa shortened the time for the yarn to complete the entire oblique-blowing and tucked-in process by 0.4625 ms, and extended the yarn elongation by 0.151 mm.

Do individuals consider expected income when valuing health states?

2008 ◽  
Vol 24 (04) ◽  
pp. 488-494 ◽  
Author(s):  
Thomas Davidson ◽  
Lars-Åke Levin
Keyword(s):  
Cost Effectiveness ◽  
Analogue Scale ◽  
Income Group ◽  
The Other ◽  
Health State ◽  
Health States ◽  
Trade Off ◽  
Productivity Costs ◽  
Effectiveness Analysis ◽  
Health State Valuations

Objectives:The purpose of this study was to empirically explore whether individuals take their expected income into consideration when directly valuing predefined health states. This was intended to help determine how to handle productivity costs due to morbidity in a cost-effectiveness analysis.Methods:Two hundred students each valued four hypothetical health states by using time trade-off (TTO) and a visual analogue scale (VAS). The students were randomly assigned to two groups. One group was simply asked, without mentioning income, to value the different health states (the non-income group). The other group was explicitly asked to consider their expected income in relation to the health states in their valuations (the income group).Results:For health states that are usually assumed to have a large effect on income, the valuations made by the income group seemed to be lower than the valuations made by the non-income group. Among the students in the non-income group, 96 percent stated that they had not thought about their expected income when they valued the health states. In the income group, 40 percent believed that their expected income had affected their valuations of the health states.Conclusion:The results show that, as long as income is not mentioned, most individuals do not seem to consider their expected income when they value health states. This indicates that productivity costs due to morbidity are not captured within individuals' health state valuations. These findings, therefore, suggest that productivity costs due to morbidity should be included as a cost in cost-effectiveness analyses.

Numerical Model Updating Technique for Estimating Load Carrying Capacities of High Speed Railway Bridges

2016 ◽  
Vol 106 (8) ◽  
pp. 490-497
Author(s):  
Dong-Uk PARK ◽  
Jae-Bong KIM ◽  
Nam-Sik KIM ◽  
Sung-Il KIM
Keyword(s):  
Numerical Model ◽  
High Speed ◽  
Model Updating ◽  
High Speed Railway ◽  
Railway Bridges ◽  
Load Carrying

Designing for Dissemination in Chronic Disease Prevention and Management

2017 ◽  
Author(s):  
Neville Owen ◽  
Ana Goode ◽  
Takemi Sugiyama ◽  
Mohammad Javad Koohsari ◽  
Genevieve Healy ◽  
...  
Keyword(s):  
Physical Activity ◽  
Chronic Disease ◽  
Cost Effectiveness ◽  
Health Behavior Change ◽  
The Other ◽  
Research Quality ◽  
Policy Initiatives ◽  
Rigorous Study ◽  
Behavior Change Program

This chapter emphasizes the need for research that is designed and implemented explicitly with dissemination in mind. This is illustrated in relation to environmental and policy initiatives to influence physical activity through active transport, and through the example of initiatives to reduce workplace sitting. The other element of this chapter, the broad-reach intervention-dissemination case study of a health behavior-change program, highlights the need to maintain key elements of research quality in designing for dissemination, to the extent that is practically possible: a rigorous study design; the systematic tracking of implementation and related costs; and, the conduct of dose-response, maintenance and cost-effectiveness analyses. These examples of designing for dissemination illustrate not only the exciting opportunities for real-world dissemination research, but also the resourcefulness and commitment required for success.

scholarly journals Black Hole Algorithm for Sustainable Design of Counterfort Retaining Walls

2020 ◽  
Vol 12 (7) ◽  
pp. 2767 ◽  
Author(s):  
Víctor Yepes ◽  
José V. Martí ◽  
José García
Keyword(s):  
Black Hole ◽  
Sustainable Design ◽  
Retaining Walls ◽  
The Other ◽  
Trade Off ◽  
Construction Company ◽  
Geometric Variables ◽  
The Stability ◽  
The Cost ◽  
Black Hole Algorithm

The optimization of the cost and CO 2 emissions in earth-retaining walls is of relevance, since these structures are often used in civil engineering. The optimization of costs is essential for the competitiveness of the construction company, and the optimization of emissions is relevant in the environmental impact of construction. To address the optimization, black hole metaheuristics were used, along with a discretization mechanism based on min–max normalization. The stability of the algorithm was evaluated with respect to the solutions obtained; the steel and concrete values obtained in both optimizations were analyzed. Additionally, the geometric variables of the structure were compared. Finally, the results obtained were compared with another algorithm that solved the problem. The results show that there is a trade-off between the use of steel and concrete. The solutions that minimize CO 2 emissions prefer the use of concrete instead of those that optimize the cost. On the other hand, when comparing the geometric variables, it is seen that most remain similar in both optimizations except for the distance between buttresses. When comparing with another algorithm, the results show a good performance in optimization using the black hole algorithm.

scholarly journals Leader-chasing behavior in negative artificial triggered lightning flashes

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fukun Wang ◽  
Jianguo Wang ◽  
Li Cai ◽  
Rui Su ◽  
Wenhan Ding ◽  
...  
Keyword(s):  
High Speed ◽  
The Other ◽  
Lightning Flash ◽  
High Speed Camera ◽  
Return Stroke ◽  
Catching Up ◽  
Special Cases ◽  
Triggered Lightning

AbstractTwo special cases of dart leader propagation were observed by the high-speed camera in the leader/return stroke sequences of a classical triggered lightning flash and an altitude-triggered lightning flash, respectively. Different from most of the subsequent return strokes preceded by only one leader, the return stroke in each case was preceded by two leaders occurring successively and competing in the same channel, which herein is named leader-chasing behavior. In one case, the polarity of the latter leader was opposite to that of the former leader and these two combined together to form a new leader, which shared the same polarity with the former leader. In the other case, the latter leader shared the same polarity with the former leader and disappeared after catching up with the former leader. The propagation of the former leader in this case seems not to be significantly influenced by the existence of the latter leader.

scholarly journals Industry update for May 2019

2019 ◽  
Vol 10 (9) ◽  
pp. 555-561
Author(s):  
Louise Rosenmayr-Templeton
Keyword(s):  
Gene Therapy ◽  
Cost Effectiveness ◽  
Spinal Muscular Atrophy ◽  
Muscular Atrophy ◽  
Clinical Results ◽  
The Other ◽  
Press Releases ◽  
The Us ◽  
True Meaning ◽  
Genetic Medicine

This industry update features a round-up of pharmaceutical news in May 2019 based on press releases and websites. The month was characterized by the achievement of significant milestones in gene therapy. The biggest of these was the US FDA’s approval of Zolgensma®. This medicine sums up the promise and price of genetic medicine. On one hand the clinical results show Zolgensma can dramatically improve the prognosis for infants with spinal muscular atrophy after just one administration, while on the other, it has been priced at around US$2.1 million. With more such therapies likely to reach the market, the debate on Zolgensma goes beyond cost, to overall affordability, the true meaning of cost–effectiveness and how to reward companies for effective, innovative medicines.

VP39 The Alphabet Lottery? How NICE Outcomes Vary By Appraisal Committee

2019 ◽  
Vol 35 (S1) ◽  
pp. 86-86
Author(s):  
Richard Macaulay ◽  
Lok Wan Liu ◽  
Cornelia Roibu ◽  
Andrea Berardi
Keyword(s):  
Cost Effectiveness ◽  
The Other ◽  
Appraisal Committee ◽  
Technology Appraisal ◽  
The Public ◽  
Chi Squared ◽  
C 50 ◽  
To Receive ◽  
Disciplinary Group ◽  
53 C 55

IntroductionNICE (National Institute for Health and Care Excellence) makes recommendations on the public reimbursement of medicines based on their clinical- and cost-effectiveness. The recommendation is made by an Appraisal Committee (comprising a multi-disciplinary group of independent experts) as part of a technology appraisal. There are four Appraisal Committees (A,B,C,D); this research investigates whether appraisal outcomes vary by committee.MethodsAll publicly-available Final Appraisal Determinations from NICE Single Technology Appraisals (STA) were screened (01/10/2009-14/11/2018) and key data were extracted. Homogeneity in rates of acceptance or rejection across the committees was assessed using Chi-squared tests.ResultsThe Appraisal Committee was identified for 298 technologies, 56% (168/298) of which were ‘recommended’. The number of technologies assessed by each committee was similar (A:79, B:62, C:91, D:66). However, STAs conducted by Committee D were significantly less likely to receive ‘recommended’ outcomes (A:68% [54/79], B:65% [40/62], C:53% [48/91], D:39% [26/66]; p < 0.01). STAs for oncology indications had higher ’not recommended’ outcomes than those for non-oncology indications (25% vs. 9%). The lower ‘recommendation’ rates for committee D persisted across oncology (A:60%, B:83%, C:50%, D:38%; p = 0.01) and non-oncology indications (A:73%, B:53%, C:55%, D:40%; p < 0.01). However, STAs conducted by Committee D were significantly more likely to receive ‘optimized’ recommendations (A:16%, B:21%, C:33%, D: 36%; p < 0.01) and when considering the rates of ‘recommended’ and ‘optimized’ outcomes compared to ‘only in research’ and ‘not recommended’ outcomes, no significant differences were found (A:85%, B: 85%, C:86%, D:76%; p = 0.27).ConclusionsSTAs undertaken by NICE Appraisal Committee D was associated with a significantly lower rate of ‘recommended’ outcomes but tended to an ‘optimized’ recommendation significantly more than the other committees. Further research is needed to determine if this reflects any deviation in uniform implementation of NICE methodology between Committees.

Sign in / Sign up

Export Citation Format

Share Document