Assessment of the operating characteristics of the SSME LOX turbopump pump-end bearing

A bearing/shaft model of the SSME LOX turbopump was developed using the SHABERTH bearing/shaft math modeling computer code. A previously developed bearing/shaft thermal model of the SSME LOX turbopump turbine and bearing was used in conjunction with SHABERTH to evaluate the thermomechanical operating characteristics of the LOX turbopump end bearings. Results show that for the two unmounted diametrical clearances evaluated (4.0 mils and 6.3 mils), the inboard pump end bearing supports about 81% of the isolator load for the small clearance and 77% of the isolator load for the larger clearance. Bearing clearance changes due to thermal effects were 40% for the 4.0 mil diametrical clearance case and 19% for the 6.3 mil clearance case evaluated. The thermal analysis included evaluation of bearing temperatures for a subcooled case and a saturated case. Results indicate that no drastic temperature change occurred between the two cases. Since the rolling element and race surfaces of the subcooled case were at temperatures sufficiently high enough to be vapor blanketed, exceeding saturation temperature at the bearing inlet did not increase surface temperatures greatly

Advanced rocket engine cryogenic turbopump bearing thermal model

A lumped node thermal model was developed representing the Space Shuttle Main Engine (SSME) liquid oxygen (LOX) turbopump turbine end bearings operating in a cryogenically cooled bearing tester. Bearing elements, shaft, carrier, housing, cryogen flow characteristics, friction heat, and fluid viscous energy are included in the model. Heat transfer characteristics for the regimes of forced convection boiling are modeled for liquid oxygen (LOX) and liquid nitrogen (LN2). Large temperature differences between the cryogenic fluid and baring contact surfaces require detailed nodal representation in these areas. Internal loads and friction heat are affected by temperature dependent operating clearances requiring iterations between bearing thermal and mechanical models. Analyses indicate a thermal-mechanical coupling resulting in reduced operating clearances, increased loading and heating which can contribute to premature bearing failure. Contact surfaces operate at temperatures above local saturation resulting in vapor rather than liquid in the contacts, precluding possible liquid film lubrication. Elevated temperatures can reduce lubrication, increase friction, and reduce surface hardness supporting a surface failure mode rather than subsurface fatigue

SOUTHERN AGRICULTURE UNDER THE 2002 FARM BILL: A REPRESENTATIVE FARMS APPROACH

The 2002 Farm Bill affects economic activity of farms and ranches in the southern United States. Using stochastic simulation techniques, key financial variables were projected for 39 representative farms and ranches in ten southern states. Results indicate 24 of 39 farms studied have more than a 40 percent likelihood of having annual cash flow deficits during the period 2002 through 2007. Results are largely consistent across commodities and between moderate and large size farms in the same geographic area.Agricultural and Food Policy,

Bearing tester data compilation, analysis and reporting and bearing math modeling, volume 1

Thermal and mechanical models of high speed angular contact ball bearings operating in LOX and LN2 were developed and verified with limited test data in an effort to further understand the parameters that determine or effect the SSME turbopump bearing operational characteristics and service life. The SHABERTH bearing analysis program which was adapted to evaluate shaft bearing systems in cryogenics is not capable of accommodating varying thermal properties and two phase flow. A bearing model with this capability was developed using the SINDA thermal analyzer. Iteration between the SHABERTH and the SINDA models enable the establishment of preliminary bounds for stable operation in LN2. These limits were established in terms of fluid flow, fluid inlet temperature, and axial load for a shaft speed of 30,000 RPM

Women Leaders in Agriculture: Data-Driven Recommendations for Action and Perspectives on Furthering the Conversation

The presence of women in positions of power in the agriculture industry is lacking. This article highlights findings generated from the 2016 Southern Region Women\u27s Agricultural Leadership Summit attended by women from 13 southern states. The research revealed that women working in Extension should (a) formally connect with leadership mentors, (b) envision themselves in leadership roles, and (c) support one another as they work to lead in the agriculture industry. To further the conversation, we provide recommendations that are inherent in the data and intended to assist early-career women professionals as well as middle managers and administrators who desire to advance women\u27s leadership development in Extension

A DOUBLE-BLIND EEG-RESPONSE TEST FOR A SUPPOSED ELECTROMAGNETIC FIELD-NEUTRALIZING DEVICE Part I: Via The Clinician Expertise Procedure

Twenty-seven individuals were evaluated for effects of a clock emitting 50 milligaus of electromagnetic field energy(EMF) upon the computerized EEG(brain map). They were then retested with either an active or placebo pendant(Clarus QLink) on the chest while again receiving 50 milligaus of electromagnetic energy applied within 6 inches of the vertex of the skull and finally retested after wearing the pendant for a month. Both subject and research technician were blinded to the active versus placebo devices. The active pendant showed significantly greater protection from the EEG disturbance induced by the electromagnetically active clock

A clinical evaluation of extended wear contact lenses

A clinical evaluation of extended wear contact lense

A Taste of Learning: A Collaborative Early Childhood Pilot Project at Grocery Stores

A Taste of Learning, a community initiative involving several collaborating agencies, has two primary foci: 1) To encourage healthy food decision-making at grocery stores and 2) to have families of young children engage in fun learning opportunities while grocery shopping. This paper provides an overview of the pilot project, which was implemented at two Remke Market stores, the preliminary findings, and the lessons learned from working with multiple partnering agencies

Psychophysiological effects of music on acute recovery from high-intensity interval training

Numerous studies have examined the multifarious effects of music applied during exercise but few have assessed the efficacy of music as an aid to recovery. Music might facilitate physiological recovery via the entrainment of respiratory rhythms with music tempo. High-intensity exercise training is not typically associated with positive affective responses, and methods of assuaging this warrant further exploration. This study assessed the psychophysiological effects of music on acute recovery and prevalence of entrainment in-between bouts of high-intensity exercise. Thirteen male runners (Mage=20.2±1.9years; BMI=21.7±1.7; V̇O2 max=61.6±6.1ml·kg·min-1) completed three exercise sessions comprising 5×5-min bouts of high-intensity intervals interspersed with a 3-min passive recovery period. During recovery, participants were administered positively-valenced music of a slow-tempo (55-65bpm), fast-tempo (125-135bpm), or a no-music control. A range of measures including affective responses, RPE, cardiorespiratory indices (gas exchange and pulmonary ventilation), and music tempo-respiratory entrainment were recorded during exercise and recovery. Fast-tempo, positively-valenced music resulted in higher Feeling Scale scores throughout recovery periods (p<0.01, ηp2=0.38). There were significant differences in HR during initial recovery periods (p<0.05, ηp2=0.16), but no other music-moderated differences in cardiorespiratory responses. In conclusion, fast-tempo, positively-valenced music applied during recovery periods engenders a more pleasant experience. However, there is limited evidence that music expedites cardiorespiratory recovery in-between bouts of high-intensity exercise. These findings have implications for athletic training strategies and individuals seeking to make high-intensity exercise sessions more pleasant