Comparison Study of Tensile Strength , Ductility, and Fracture Mode of H11, ARP 2000, and MP35N Connecting Rod Bolts for Use in High Performance Racing Engines

Oliver Racing Parts (ORP) has historically purchased connecting rod bolts made of high strength, high cost, nickel-cobalt alloy, MP35N, and a medium strength, low cost, proprietary tool steel called ARP 2000. ORP has recently acquired capabilities to manufacture their own bolts. To determine the quality of their product as it compares to their previous supplier, ORP produced three different types of ⅜” diameter bolts: one set of bolts made of MP35N, and two sets of H11 bolts, designated H11A and H11B for their respective processing. The H11, ARP 2000, and MP35N bolts were tensile tested using a custom designed test fixture. The ultimate tensile strength, percent elongation, and percent reduction in area were measured. The fracture mode of each bolt was also investigated. 30 bolts from each lot were tested, except the H11A, the strength of which exceeded the limitation of the test fixture. The chief purpose of this investigation was to determine if there were significant differences between the H11 and ARP 2000 bolts, and between the MP35N bolts from the different companies. The data acquired proved that both heat treatments of H11 are both significantly stronger than ARP 2000, and that there is no discernable difference in strength between the MP35N bolts produced by the two different companies

Tandem Fan Applications in Advanced STOVL Fighter Configurations

The series/parallel tandem fan engine is evaluated for application in advanced STOVL supersonic fighter aircraft. Options in engine cycle parameters and design of the front fan flow diverter are examined for their effects on engine weight, dimensions, and other factors in integration of the engine with the aircraft. Operation of the engine in high-bypass flow mode during cruise and loiter flight is considered as a means of minimizizng fuel consumption. Engine thrust augmentation by burning in the front fan exhaust is discussed. Achievement of very sort takeoff with vectored thrust in briefly reviewed for tandem fan engine configurations with vectorable front fan nozzles. Examples are given of two aircraft configuration planforms, a delta-canard, and a forward-swept wing, to illustrate the major features. design considerations, and potential performance of the tandem fan installation in each. Full realization of the advantages of tandem fan propulsion are found to depend on careful selection of the aircraft configuration, since integration requirements can strongly influence the engine performance

An Approach to Overcoming Specific Difficulties with Cardiac Resynchronization Therapy in Children

Cardiac resynchronization therapy (CRT) is now a well established treatment modality for adult patients with drug refractory symptomatic congestive heart failure. Multiple large-scale studies have clearly demonstrated reduction in heart failure-related morbidity with CRT. More recently, a likely independent mortality benefit with CRT has also been shown. Improvement in quality of life, decrease in left ventricular diastolic dimension, improved objective assessment of exercise tolerance, and decreased heart failure-related hospitalizations have all been well demonstrated in the adult population. Whether or not these benefits occur in younger patients is not clear. Since none of the major trials for CRT have included children, much is unknown about the specifics of indication, difficulties with implant, and efficacy in the pediatric populatio

ACUTE EFFECTS OF SURFACE TYPE ON BIOMECHANICAL PARAMETERS OF RUNNING

The purpose of this study was to examine whether an acute bout of exercise on a compliant versus non-compliant surface could reveal biomechanical indicators of injury. Twelve college-aged seasoned cross-country runners performed two bouts of 20 minute runs, one on grass and one on asphalt, one week apart. Changes (pre vs. post) measures in contact time (s), impulse (Ns) and peak vertical force (N) showed no significant differences based on surface type. The results show that an acute bout of exercise on either surface will not be different in terms of potential for injury. However, the chronic effects of running on different surfaces should be examined using fatigue levels to determine

Social media use by community-based organizations conducting health promotion: a content analysis

Background: Community-based organizations (CBOs) are critical channels for the delivery of health promotion programs. Much of their influence comes from the relationships they have with community members and other key stakeholders and they may be able to harness the power of social media tools to develop and maintain these relationships. There are limited data describing if and how CBOs are using social media. This study assesses the extent to which CBOs engaged in health promotion use popular social media channels, the types of content typically shared, and the extent to which the interactive aspects of social media tools are utilized. Methods: We assessed the social media presence and patterns of usage of CBOs engaged in health promotion in Boston, Lawrence, and Worcester, Massachusetts. We coded content on three popular channels: Facebook, Twitter, and YouTube. We used content analysis techniques to quantitatively summarize posts, tweets, and videos on these channels, respectively. For each organization, we coded all content put forth by the CBO on the three channels in a 30-day window. Two coders were trained and conducted the coding. Data were collected between November 2011 and January 2012. Results: A total of 166 organizations were included in our census. We found that 42% of organizations used at least one of the channels of interest. Across the three channels, organization promotion was the most common theme for content (66% of posts, 63% of tweets, and 93% of videos included this content). Most organizations updated Facebook and Twitter content at rates close to recommended frequencies. We found limited interaction/engagement with audience members. Conclusions: Much of the use of social media tools appeared to be uni-directional, a flow of information from the organization to the audience. By better leveraging opportunities for interaction and user engagement, these organizations can reap greater benefits from the non-trivial investment required to use social media well. Future research should assess links between use patterns and organizational characteristics, staff perspectives, and audience engagement

Optimizing the Model of the Viking-400 UAS

This project intends to update and redesign imperfections in the scanned 3D CAD model of the Viking 400 aircraft. This aircraft, similar to the Sierra-B UAS, will carry payloads of scientific instruments for research purposes. The goals of this project are to modify the current scanned model such that it better represents the physical qualities of the aircraft, as well as creating the features that are missing from the model. As the model was imported from a different software, many of the critical surfaces did not accurately reflect the actual aircraft. Those parts of the model were redesigned entirely so that they can be edited for future use, as well as correctly representing the aircraft as it is now. Additionally, parts of the aircraft that did not appear in the scanned model were designed and added to the new model. In order to prioritize ease of use for future missions, the model has been reorganized in a logical fashion that enables modification of specific parts of the aircraft. The organization of this model imitates the drawing tree of the Sierra-B, with the intention of maintaining a functional system of redesign, analysis, and implementation. Ultimately, this project will be a catalyst for making Viking 400 into a functional aircraft and increasing scientific research in airborne vehicles

The effects of competition on fitness depend on the sex of both competitors

In intraspecific competition, the sex of competing individuals is likely to be important in determining the outcome of competitive interactions and the way exposure to conspecifics during development influences adult fitness traits. Previous studies have explored differences between males and females in their response to intraspecific competition. However, few have tested how the sex of the competitors, or any interactions between focal and competitor sex, influences the nature and intensity of competition. We set up larval seed beetles Callosobruchus maculatus to develop either alone or in the presence of a male or female competitor and measured a suite of traits: development time, emergence weight; male ejaculate mass, copulation duration, and lifespan; and female lifetime fecundity, offspring egg-adult survival, and lifespan. We found effects of competition and competitor sex on the development time and emergence weight of both males and females, and also of an interaction between focal and competitor sex: Females emerged lighter when competing with another female, while males did not. There was little effect of larval competition on male and female adult fitness traits, with the exception of the effect of a female competitor on a focal female's offspring survival rate. Our results highlight the importance of directly measuring the effects of competition on fitness traits, rather than distant proxies for fitness, and suggest that competition with the sex with the greater resource requirements (here females) might play a role in driving trait evolution. We also found that male-male competition during development resulted in shorter copulation times than male-female competition, a result that remained when controlling for the weight of competitors. Although it is difficult to definitively tease apart the effects of social environment and access to resources, this result suggests that something about the sex of competitors other than their size is driving this pattern.Funding for this project was provided by the Australian Research Council (FT160100149 to MLH and FT110100453 to LEBK

Cotyledonoid dissecting leiomyoma in pregnancy: a case report

Cotyledonoid dissecting leiomyoma (CDL) is a rare variant of uterine leiomyoma characterized by intramural dissection within the uterine corpus and a distinctive gross appearance resembling the cotyledons of the placenta. Despite their alarming, sarcomatous appearance both macroscopically and radiographically, these tumors are typically associated with bland histologic findings. Approximately 70 cases of CDL have been described in the literature. This case represents the second described case of CDL in pregnancy, the first in which a pregnancy was carried to term. A 28-year-old primigravid was incidentally found to have a massive, exophytic growth of the uterus on ultrasound with concomitant 14-week intrauterine pregnancy. The pregnancy was monitored with serial growth ultrasounds. She was delivered at 37 weeks via Cesarean section. After being lost to follow-up, the patient presented 2.5 years later with worsening abdominal fullness and persistent uterine mass

The dark side of FIRE: predicting the population of dark matter subhaloes around Milky Way-mass galaxies

A variety of observational campaigns seek to test dark-matter models by measuring dark-matter subhaloes at low masses. Despite their predicted lack of stars, these subhaloes may be detectable through gravitational lensing or via their gravitational perturbations on stellar streams. To set measurable expectations for subhalo populations within LambdaCDM, we examine 11 Milky Way (MW)-mass haloes from the FIRE-2 baryonic simulations, quantifying the counts and orbital fluxes for subhaloes with properties relevant to stellar stream interactions: masses down to 10^6 Msun, distances < 50 kpc of the galactic center, across z = 0 - 1 (lookback time 0 - 8 Gyr). We provide fits to our results and their dependence on subhalo mass, distance, and lookback time, for use in (semi)analytic models. A typical MW-mass halo contains ~16 subhaloes >10^7 Msun (~1 subhalo >10^8 Msun) within 50 kpc at z = 0. We compare our results with dark-matter-only versions of the same simulations: because they lack a central galaxy potential, they overpredict subhalo counts by 2-10x, more so at smaller distances. Subhalo counts around a given MW-mass galaxy declined over time, being ~10x higher at z = 1 than at z = 0. Subhaloes have nearly isotropic orbital velocity distributions at z = 0. Across our simulations, we also identified 4 analogs of Large Magellanic Cloud satellite passages; these analogs enhance subhalo counts by 1.4-2.7 times, significantly increasing the expected subhalo population around the MW today. Our results imply an interaction rate of ~5 per Gyr for a stream like GD-1, sufficient to make subhalo-stream interactions a promising method of measuring dark subhaloes.Comment: 13 pages, submitted to MNRA