Utilizing an application specific integrated circuit (ASIC) with 140 different shift chains, and a wide variety of test modes, a design of experiments (DOE) approach was used to characterize a ...commercial 90 nm CMOS technology for its sensitivity to single event effects (SEE). The variables characterized included: well structure on the wafer, density of well contacts, logic data pattern, angle of indicence, flip-flop redundancy, variation in sensitive node spacing, and the effect of transients as a function of combinatorial logic type. Analysis of the cross section contribution from the clock, flip-flop and SET target circuitry showed that any hardening technique used in a production integrated circuit may be limited in its effectiveness due to other circuits and logic in the integrated circuit.
Research and analysis of braking issues for golf cars and other low speed vehicles (LSVs) are reported in this study. It is shown that many such vehicles only provide braking for their rear wheels, ...which can lead to a driver losing control during travel on typical steep downgrades. The braking performance of a golf car equipped with brakes on two or four wheels was analyzed to determine the effects of two and four wheel brake designs on braking efficiency and vehicle yaw stability. Besides reducing braking efficiency, it is demonstrated that installing brakes on only the rear wheels can lead to directional instability (fishtailing) and rollover when the rear wheels are braked until skidding occurs. The nonexistence of golf course standards and the inadequacy of golf car and LSV standards are noted and a connection between this and the comparatively high level of accidents with such vehicles is inferred. Based on these results, it is advisable to install brakes on all four wheels of golf cars and LSVs. In addition, new safety standards should be considered to reduce the occurrence of golf car accidents on steep downhill slopes.
This paper describes research and parametric analyses of braking effectiveness and directional stability for golf cars, personal transport vehicles (PTVs) and low speed vehicles (LSVs). It is shown ...that current designs, which employ brakes on only the rear wheels, can lead to rollovers if the brakes are applied while traveling downhill. After summarizing the current state of existing safety standards and brake system designs, both of which appear deficient from a safety perspective, a previously developed dynamic simulation model is used to identify which parameters have the greatest influence on the vehicles’ yaw stability. The simulation results are then used to parametrically quantify which combination of these factors can lead to yaw induced rollover during hard braking. Vehicle velocity, steering input, path slope and tire friction are all identified as important parameters in determining braking stability, the effects of which on rollover propensity are presented graphically. The results further show that when vehicles are equipped with front brakes or four-wheel brakes, the probability of a yaw induced rollover is almost entirely eliminated. Furthermore, the parametric charts provided may be used as an aid in developing guidelines for golf car and PTV path design if rear brake vehicles are used.
Current golf carts and LSV's (Low Speed Vehicles) produce a significant number of passenger ejections during sharp turns. These LSV's do not typically possess seatbelts, but do provide outboard bench ...seat hip restraints that also serve as handholds. However, many current restraint designs appear incapable of preventing passenger ejections due to their low height and inefficient handhold position. Alternative handhold and hip restraint designs may improve passenger safety. Accordingly, this paper examines minimum size requirements for hip restraints to prevent passenger ejection during sharp turns and evaluates the effectiveness of a handhold mounted at the center of the bench seat. In this study, a simulation of a turning cart supplies the dynamic input to a biomechanical model of an adult male seated in a golf cart. Various restraint combinations are considered, both with and without the central handhold, to determine the likelihood of passenger ejection. It is shown that only the largest restraint geometries prevent passenger ejection. Adequate hip restraints should be much larger than current designs and a central handhold should be provided. In this way, golf cart and LSV manufacturers could reduce passenger ejections and improve fleet safety by incorporating recommendations provided herein.
The Role of Human Balance in Stepladder Accidents Tichon, Daniel; Baker, Lowell L.; Ojalvo, Irving U.
Proceedings of the Human Factors and Ergonomics Society Annual Meeting,
09/2011, Letnik:
55, Številka:
1
Journal Article
Recenzirano
Ladder accidents account for nearly 200,000 hospital emergency room visits per year in the United States, with a large proportion of these being due to falls from stepladders (CPSC, 2010). This paper ...explores various aspects of human balance that are of particular importance for stepladder users with an eye towards better understanding, and reducing the number of, falls from stepladders. We review and discuss human balance literature that is relevant to stepladder use, as well as current ladder designs and standards, to better understand how and why losses of balance on stepladders occur. Based on these findings, we make recommendations concerning ladder design and user behavior that are expected to improve stepladder safety. Directions for further research in this area are also proposed.
We study the Higgs pair production process at a muon collider using b-pair decays of the Higgs bosons. Efficient identification and good measurement resolution for the b-jet pair invariant mass are ...crucial for unearthing the di-Higgs signal. However, the beam-induced background has potential to drastically degrade the performance. We report on the full simulation studies of the degradation of the reconstructed b-jet pair invariant mass in di-Higgs events, considering only the beam-induced background in the calorimeter. Mitigation strategies for the suppression of the beam-induced background are underway. We also report prospects for the measurement of the Standard Model Higgs pair production at the Muon Colliders at various benchmarks of the collider center of mass energy and integrated luminosity using a fast simulation program.
Accidental falls from stepladders are responsible for tens of thousands of injuries in the US each year. This paper augues recent research concerning excessive stepladder twist flexibility, which can ...lead to ladder falls. Such falls can easily occur when only three of a ladder's four legs are in contact with the ground and an unknowing climber shifts his weight, causing the ladder's raised leg to move suddenly downward and the climber to lose his balance. The static and dynamic test and analysis results presented show a major cause of this hazard, its effect on climbers and the influence of ladder design on the likelihood of its occurrence. The inadequacy of existing stepladder safety standards to protect against such accidents is noted and a call for a new testing standard is outlined. It would be prudent to develop and implement a new racking test and stiffer ladder twist requirements to reduce the likelihood of inadvertent ladder racking.
Muon Collider Forum Report D Li; Maltoni, F; Acosta, D ...
arXiv (Cornell University),
08/2023
Paper, Journal Article
Odprti dostop
A multi-TeV muon collider offers a spectacular opportunity in the direct exploration of the energy frontier. Offering a combination of unprecedented energy collisions in a comparatively clean ...leptonic environment, a high energy muon collider has the unique potential to provide both precision measurements and the highest energy reach in one machine that cannot be paralleled by any currently available technology. The topic generated a lot of excitement in Snowmass meetings and continues to attract a large number of supporters, including many from the early career community. In light of this very strong interest within the US particle physics community, Snowmass Energy, Theory and Accelerator Frontiers created a cross-frontier Muon Collider Forum in November of 2020. The Forum has been meeting on a monthly basis and organized several topical workshops dedicated to physics, accelerator technology, and detector R&D. Findings of the Forum are summarized in this report.
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