The Experts below are selected from a list of 174 Experts worldwide ranked by ideXlab platform
Morton E Okelly - One of the best experts on this subject based on the ideXlab platform.
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fuel burn rates of commercial passenger aircraft variations by Seat Configuration and stage distance
Journal of Transport Geography, 2014Co-Authors: Yongha Park, Morton E OkellyAbstract:Abstract Aircraft fuel consumption is a very large component of airline costs. Fuel burn is also very important because it is highly correlated with emissions and contributes directly to transport externalities. This paper calibrates fuel burn in kilos per Seat per nautical mile for aircraft using the EMEP/EEA aircraft inventory database. We then employ the model with OAG flight schedule data to evaluate fuel burn by flight routes and aircraft types at a global scale. The paper shows comparative fuel use among different distance based markets as well as among a variety of routes in the long-haul market. The results show geographical heterogeneity of fuel burn rates among a variety of routes, while controlling for Seat Configuration and stage distance. The paper finds that stage lengths centered on 1500–2000 NM have the lowest fuel burn rates under current technology, fleet composition, and Seat Configuration. These findings, together with comments on the viability of long range flights provide better understandings not only for the carbon taxation debates but also for operational efficiency of current aviation markets. The lower rates for moderate distance flights seems to favor networks without extreme links, and supports the use of a hub connection scheme.
Mieczysław Wojtkowiak - One of the best experts on this subject based on the ideXlab platform.
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Back pain in Polish military helicopter pilots
International Journal of Occupational Medicine and Environmental Health, 2012Co-Authors: Aleksandra Truszczyńska, Rafał Lewkowicz, Olaf Truszczyński, Kazimierz Rąpała, Mieczysław WojtkowiakAbstract:Objectives Low back pain in pilots of military helicopters is widely discussed in the world literature. Vibrations and improper Seat Configuration cause that cervical, thoracic and lumbar spine might be exposed to overloading. The aim of the study was to determine the incidence and intensity of pain in the spine as well as to identify subjective risk factors of back pain and its effect on the pilot’s actions while flying a helicopter.
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Back pain in Polish military helicopter pilots
International Journal of Occupational Medicine and Environmental Health, 2012Co-Authors: Aleksandra Truszczyńska, Rafał Lewkowicz, Olaf Truszczyński, Kazimierz Rąpała, Mieczysław WojtkowiakAbstract:Objectives Low back pain in pilots of military helicopters is widely discussed in the world literature. Vibrations and improper Seat Configuration cause that cervical, thoracic and lumbar spine might be exposed to overloading. The aim of the study was to determine the incidence and intensity of pain in the spine as well as to identify subjective risk factors of back pain and its effect on the pilot’s actions while flying a helicopter. Materials and Methods 112 pilots, aged 25–56 years (mean age: 34.8±6.3 years), actively flying helicopters, participated in the questionnaire survey. The questionnaire containing five groups of questions, elaborated by the authors, was used. Results 70% of the pilots reported pain complaints. Pain was localized in different parts of the spine. Uncomfortable body posture during prolonged flights resulting from the lack of lumbar support exerted the highest effect on pain provocation. Conclusions This questionnaire survey enabled to determine the prevalence of pain, its type and intensity. Knowledge on low back pain imposes the necessity to eliminate the negative environmental effect on helicopter pilotage. Elimination of risk factors is possible through appropriate physical exercises and adjustment of pilots’ Seats. The authors plan to conduct — in the future — detailed annual examinations among pilots with back pain and, based on the results, to elaborate a prophylactic program containing simple forms of isometric and isotonic training involving paravertebral and deep abdominal muscles designed specifically for pilots of military helicopters.
Chris E. Perry - One of the best experts on this subject based on the ideXlab platform.
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ATD Biodynamics During Lateral Impact for USAF Neck Injury Criteria
Safety, 2019Co-Authors: Chris E. Perry, John R. Buhrman, Casey W. Pirnstill, John McintireAbstract:Research was conducted involving a series of lateral impact tests on a horizontal sled facility by scientists at the Air Force Research Laboratory (AFRL). The purpose of the research was to conduct an assessment of the biodynamic response of an anthropomorphic test device (ATD) to support the development of AFRL neck injury criteria. Impacts were completed using a 50th male Hybrid III aerospace ATD due to this ATD being used by the USAF to qualify and evaluate ejection systems. A test matrix was developed to assess ATD response as a function of various Seat Configurations which were an approximation of the Seat Configurations used by the Medical College of Wisconsin (MCW) for previously conducted lateral impact tests of PMHS subjects (post-mortem human subjects). The specially fabricated Seat Configurations were a rigid Seat fixture with a 5-point harness and a padded rigid Seat with a 3-point harness. The input acceleration pulses were trapezoidal in shape and varied in peak magnitude from 8.5 to 17 G. The rigid and padded Seat Configurations both generated fairly linear ATD responses across the input acceleration range. The ATD’s response with the padded Seat and the 3-point restraint was greater than the ATD’s response with the rigid Seat and the 5-point restraint with the upper neck. The My torque showed the greatest increase from the rigid Seat Configuration to the padded Seat Configuration. This highlights the importance of a proper restraint and the importance of controlling the motion of the torso since it could reduce the loads and torques of the unrestrained head and neck, resulting in a lower probability of injury. The lateral impact program with the ATD provided critical impact data to fill data gaps that support the development of the ATD-to-human transfer functions for AFRL’s Multi-Axial Neck Injury Criteria (MANIC) for lateral impact or MANICy calculation. The program also highlighted gaps in human and PMHS head response data in identical lateral impact Configurations that would not only improve the current MANICy transfer function but would allow the investigation of the efficacy of using the 6F-MANICy to replace the current MANICy.
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Comparative Assessment of Torso and Seat Mounted Restraint Systems using Manikins on the Vertical Deceleration Tower
2017Co-Authors: Chris E. Perry, Chris Burneka, John R. Buhrman, Rachael Christopher, Chris AlberyAbstract:Abstract : An experimental effort involving a series of +z-axis impact tests was conducted on the 711th Human Performance Wings Vertical Deceleration Tower (VDT). The purpose of the tests was to perform a comparative assessment of Seat and torso mounted restraint systems during the simulated catapult phase. Parametric assessment was also conducted with other parameters including catapult acceleration, headrest position relative to Seatback tangent plane, and head supported mass (helmet system). Overall, the series of comparative assessments indicated that a forward headrest of 2.5 in. relative to the Seat back and a heavy helmet of 5 lb with a forward cg shift generate greater biodynamic responses during the catapult phase of ejection for both the LOIS and the LARD manikin . The comparative assessment with the SCH indicated that it provided equivalent control of head and torso motion for each manikin relative to the torso harness except for allowing larger shoulder loads for LARD at the 15 G impact level. Risk of neck injury as determined by the AFRL Neck Injury Criteria (primarily MANICxz or Nij) for those comparative assessments were below establish AFRL risk of injury values. The Nij compression/flexion values were the most critical in all cases. Comparing a baseline ejection Seat Configuration (combined baseline test parameters) and a JSF-styled ejection Seat Configuration (combined non-baseline test parameters) produced similar biodynamic response parameters for the LOIS and the LARD, but the JSF-styled Seat generated a greater risk of neck injury to the occupant at all impact levels. Maximum lumbar loads produced by LARD at 15 G for the harness Configuration comparison and the Seat Configuration comparison were greater for the SCH and the JSF-styled Seat, but still below accepted AFRL lumbar load limits. All the data sets collected for this effort will be used in a future human impact study with similar comparative assessments for prediction of biodynamic response.
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H-60A/L Cargo Compartment Ingress and Egress Evaluation of Current and Prototype Troop Seating
2012Co-Authors: Nathan L Wright, Chris E. Perry, Brian J Grattan, Greg A ThompsonAbstract:Abstract : Ingress and egress evaluation of both current and prototype H-60A/L rotorcraft troop Seating was completed by 711HPW/RHCP and performed at HX-21 Squadron, Naval Air Warfare Center Aircraft Division, Patuxent River, MD on December 2011. The H-60A/L troop Seat, a prototype all-fabric troop Seat by Glatz Aeronautical, and a prototype Seat by Wolf Technical Services were tested. Ten examples of each Seat were installed in a MH-60S rotorcraft per Seat Configuration, and multiple ingress and egress trials were performed by Marines from Marine Corp Base Quantico, VA outfitted in battle gear. Ingress and egress times were averaged and compared using a one-way ANOVA to determine statistical differences between Seats. The H-60A/L Seat had a statistically significant lower ingress time compared to the Glatz and Wolf Seats. The H-60A/L Seat had a statistically lower egress time from the Wolf Seat, though no difference was shown between the H-60A/L and Glatz Seats as well as the Glatz and Wolf Seats. Whether or not these differences are operationally significant is beyond the scope of this study.
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Investigation of Occupant Restraint Improvements to the SIIIS-3 Ejection Seat.
1999Co-Authors: Steven M. Pint, Chris E. PerryAbstract:Abstract : During the Front Line Ejection Equipment Tests (FLEET) program, higher than anticipated radical values were recorded using the 103 lb Lightest Occupant In Service (LOIS) manikin ejecting in the SIIIS-3 ejection Seat with and F-15 forebody. The radical value is calculated using the Seat acceleration in the x and y axes, and the Dynamic Response (DR) in the z axis. It was observed that the LOIS manikin was poorly restrained in the Seat regardless of the tension applied to the harness strap. Three concepts have been identified that can be readily incorporated into the Seat to improve occupant restraint. These concepts are: an improved Seat cushion using a conforming material, inertia reel rollers that are fixed with respect to the headbox, and inflatable elements attached to the lap-belt as pace fillers. Tests with manikins were performed to evaluate the proposed improvements. The large ADAM (218 lb) manikin and the LOIS manikin were subjected to impacts along the +z, -x, and +y axes using the AFRL Vertical Deceleration Tower (VDT) and Horizontal Impulse Accelerator (HIA). Test were conducted with the original Seat Configuration and with the proposed improvements incorporated into the Seat Manikin response characteristics were measured and results were compared to determine the improvements provided by the modifications to the SIIIS ejection Seat.
Peter Vink - One of the best experts on this subject based on the ideXlab platform.
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future vehicles the effect of Seat Configuration on posture and quality of conversation
Ergonomics, 2019Co-Authors: Iolanda Fiorillo, Silvana Piro, Shabila Anjani, Maxim Smulders, Yu Song, Alessandro Naddeo, Peter VinkAbstract:AbstractThe percentage of passengers that prefer travelling in groups is increasing. In most vehicles, passengers sit side by side and need to turn their body to be engaged in the conversation with...
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Posture variation in a car within the restrictions of the driving task.
Work-a Journal of Prevention Assessment & Rehabilitation, 2016Co-Authors: Sigrid Van Veen, Peter VinkAbstract:BACKGROUND: Passive posture variation in vehicles could enable variation in pressure distribution and muscle activity to counter physical fatigue from static Seating resulting in more comfort. The difference in posture, however, should not lead to perceived discomfort and aspects of driving should be considered such as operating the steering wheel, pedals and vision in the mirrors. OBJECTIVE: This study sets out to find out how much postural variation occurs during the driving task and how sensitive is the human body to these changes. METHODS: The first experiment was user evaluation and assessed how and when the changes in Seat Configuration were noticeable to the human body. The second experiment evaluated the influence of varying inclination of the backrest and the Seat pan by the rating of typical aspects of driving. RESULTS: The differences in Seat Configuration during experiment 1, were so small that there was no consistency in the ratings for the same Configuration. The most critical feature that restrains the posture is the location of the rear view mirror. CONCLUSIONS: The range-of-motion is defined as –1 ◦ to +1 ◦ for the Seat pan and 0 ◦ to +1.5 ◦ for the backrest based on the results of experiment 2 because of the restraints of the driving task.
Yongha Park - One of the best experts on this subject based on the ideXlab platform.
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fuel burn rates of commercial passenger aircraft variations by Seat Configuration and stage distance
Journal of Transport Geography, 2014Co-Authors: Yongha Park, Morton E OkellyAbstract:Abstract Aircraft fuel consumption is a very large component of airline costs. Fuel burn is also very important because it is highly correlated with emissions and contributes directly to transport externalities. This paper calibrates fuel burn in kilos per Seat per nautical mile for aircraft using the EMEP/EEA aircraft inventory database. We then employ the model with OAG flight schedule data to evaluate fuel burn by flight routes and aircraft types at a global scale. The paper shows comparative fuel use among different distance based markets as well as among a variety of routes in the long-haul market. The results show geographical heterogeneity of fuel burn rates among a variety of routes, while controlling for Seat Configuration and stage distance. The paper finds that stage lengths centered on 1500–2000 NM have the lowest fuel burn rates under current technology, fleet composition, and Seat Configuration. These findings, together with comments on the viability of long range flights provide better understandings not only for the carbon taxation debates but also for operational efficiency of current aviation markets. The lower rates for moderate distance flights seems to favor networks without extreme links, and supports the use of a hub connection scheme.
