Noise of the Harrier in vertical landing and takeoff

The noise of the Harrier AV8C aircraft in vertical takeoff and landing was measured 100 feet to the side of the aircraft where jet noise dominates. The noise levels were quite high - up to 125 dB overall sound level at 100 feet. The increased noise due to jet impingement on the ground is presented as a function of jet height to diameter ratio. The impingement noise with the aircraft close to the ground was 14 to 17 dB greater than noise from a free jet. Results are compared with small-scale jet impingement data acquired elsewhere. The agreement between small-scale and full-scale noise increase in ground effect is fairly good except with the jet close to the ground. It is proposed that differences in the jet Reynolds numbers and the resultant character of the jets may be partially responsible for the disparity in the full-scale and small-scale jet impingement noise. The difference between single-jet impingement and multiple-jet impingement may also have been responsible for the small-scale and full-scale disagreement

USING NAMING CONVENTIONS TO FACILITATE DATA TRANSFER BETWEEN ASSET MANAGEMENT SYSTEMS AND BUILDING INFORMATION MODELS

An improvement to the workflow developed by Loeh et al. (2021) is proposed using a Revit template with BUILDER SMS naming conventions when creating the Sustainable Facility Management-enhanced BIM Model. The method presented by Loeh et al. (2021) is modified by integrating BUILDER SMS parameters and naming conventions into the BIM model during, as opposed to after, the creation of the model. Four building models created in 2020-21, four from 2021-22, and one building from 2019 were used in this study. Two groups of students were used to evaluate the effect of the building-specific BIM templates. Evaluating the 2020 and 2021 group\u27s progress logs\u27 milestone completion times using the T-test and ANOVA indicated that using the building-specific BIM template did not take significantly more time than allowing model builders complete freedom regarding naming conventions when creating BIM models. The initial time commitment required to create the building-specific template makes it easier to identify the location of elements in the model. Developing the Revit model with the BUILDER SMS naming convention in mind creates a compatible BIM model for transferring data

Assessment of the relationships between myocardial contractility and infarct tissue revealed by serial magnetic resonance imaging in patients with acute myocardial infarction

Imaging changes in left ventricular (LV) volumes during the cardiac cycle and LV ejection fraction do not provide information on regional contractility. Displacement ENcoding with Stimulated Echoes (DENSE) is a strain-encoded cardiac magnetic resonance (CMR) technique that measures strain directly. We investigated the relationships between strain revealed by DENSE and the presence and extent of infarction in patients with recent myocardial infarction (MI). 50 male subjects were invited to undergo serial CMR within 7 days of MI (baseline) and after 6 months (follow-up; n = 47). DENSE and late gadolinium enhancement (LGE) images were acquired to enable localised regional quantification of peak circumferential strain (Ecc) and the extent of infarction, respectively. We assessed: (1) receiver operating characteristic (ROC) analysis for the classification of LGE, (2) strain differences according to LGE status (remote, adjacent, infarcted) and (3) changes in strain revealed between baseline and follow-up. 300 and 258 myocardial segments were available for analysis at baseline and follow-up respectively. LGE was present in 130/300 (43 %) and 97/258 (38 %) segments, respectively. ROC analysis revealed moderately high values for peak Ecc at baseline [threshold 12.8 %; area-under-curve (AUC) 0.88, sensitivity 84 %, specificity 78 %] and at follow-up (threshold 15.8 %; AUC 0.76, sensitivity 85 %, specificity 64 %). Differences were observed between remote, adjacent and infarcted segments. Between baseline and follow-up, increases in peak Ecc were observed in infarcted segments (median difference of 5.6 %) and in adjacent segments (1.5 %). Peak Ecc at baseline was indicative of the change in LGE status between baseline and follow-up. Strain-encoded CMR with DENSE has the potential to provide clinically useful information on contractility and its recovery over time in patients with MI

Possible Subglacial Origin for Minor Moraine Topography

Surface expression of the Cary Age Drift (Des Moines lobe of Iowa) exhibits a pattern of intersecting linear ridges and depressions, known as swell-swale or minor moraine topography. Linear ridges, as mapped from air photos, are aligned either parallel or approximately transverse (45° to 90°) to associated end morainal systems. Both parallel and transverse ridges appear genetically related, range in height from 5-20 feet and are composed predominantly of till. Ridge intersections produce T , offset step and box patterns. The irregular shape and high dip of crossbedding of small sand bodies and the dip of small faults and joints suggest a controlled ice disintegration origin. Alignment of till fabric with glacier flow is indicative of a lodgment till or ground moraine. The current hypothesis that the minor moraines represent annual recessional moraines does not explain the lack of outwash, the origin of transverse ridges, till fabric, the number of moraines and their geographic distribution. Alternate hypotheses for the observed pattern are: 1) crevasse fill 2) ice marginal thrust 3) basal crevasse squeeze and 5) boundary wave phenomenon

Monitoring and assessing land degradation: new approaches

This chapter examines land degradation in southern Africa. The focus is on the major issue of erosion by water at scales ranging from a few square metres to assessments that aim to cover the whole region. Approaches to measure and reconstruct both current and historical erosion rates are considered, focusing on the period since the arrival of Europeans who brought many of their farming and management practices with them. In most parts of the country, the impact of humans on the landscape has been clear for the last 200 years. This is referred to as ’accelerated erosion’, i.e., erosion at rates that are above the natural geological norm for the current climatic conditions. The chapter considers a range of techniques including direct measurement, remote sensing, fingerprinting and modelling as approaches to the monitoring and assess land degradation

Integrated control and display research for transition and vertical flight on the NASA V/STOL Research Aircraft (VSRA)

Results of a substantial body of ground-based simulation experiments indicate that a high degree of precision of operation for recovery aboard small ships in heavy seas and low visibility with acceptable levels of effort by the pilot can be achieved by integrating the aircraft flight and propulsion controls. The availability of digital fly-by-wire controls makes it feasible to implement an integrated control design to achieve and demonstrate in flight the operational benefits promised by the simulation experience. It remains to validate these systems concepts in flight to establish their value for advanced short takeoff vertical landing (STOVL) aircraft designs. This paper summarizes analytical studies and simulation experiments which provide a basis for the flight research program that will develop and validate critical technologies for advanced STOVL aircraft through the development and evaluation of advanced, integrated control and display concepts, and lays out the plan for the flight program that will be conducted on NASA's V/STOL Research Aircraft (VSRA)