Patrick C. Kelly

Texas A&M University

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Homer Rahnejat

Loughborough University

Stephanos Theodossiades

Loughborough University

Michael R. Weir

Scott & White Memorial Hospital

Manoranjan Majji

Texas A&M University System

Mahdi Mohammadpour

Islamic Azad University, Science and Research Branch

Eliot Motato

University of Indianapolis

D. Michael McFarland

Zhejiang University of Technology

Lawrence A. Bergman

University of Illinois Urbana-Champaign

Malika Perera

Sri Lanka Institute of Information Technology

Miguel De la Cruz

Instituto Nacional de Enfermedades Neoplásicas

Cooperative Institutions

Agence Nationale de Recherches sur le Sida et les Hépatites Virales

Loughborough University

Madigan Army Medical Center

University of Washington

University of Illinois Urbana-Champaign

Vanderbilt University

William Beaumont Army Medical Center

Walter Reed Army Institute of Research

Maricopa Medical Center

VA Puget Sound Health Care System

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Elasto-Multi-Body Dynamics of Multi-Cylinder Internal Combustion Engine

Sumit Y. Gupta Patrick C. Kelly Homer Rahnejat

Abstract The paper presents a multi-body model of a 4-cylinder, 4-stroke diesel engine, incorporating component flexibility. The model also comprises engine firing order and experimentally measured combustion time history. The paper presents numerical predictions for conical motion of the flywheel due to combined torsion-deflection modes of the flexible crankshaft system. The half-engine order responses induce the complex 3-dimensional whirling motion of the flywheel, which is responsible for repetitive shock loading of the drivetrain system through impact with the clutch system. This leads to an assortment of noise and vibration concerns, one of which is the in-cycle vibration of the clutch system. Numerical prediction of this vibration response conforms well with the experimental findings, both of which are reported in this paper.

Flywheel

Torsional Vibration

10.1115/imece2001/de-23234

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Citations (9)

The Effect of Thermo-Hydrodynamics on Manual Automotive Transmissions Gear Rattle

Miguel De la Cruz Stephanos Theodossiades Homer Rahnejat Patrick C. Kelly

Manual transmission gear rattle is the result of repetitive impacts of gear meshing teeth within their backlash. This NVH phenomenon is a major industrial concern and can occur under various loaded or unloaded conditions. It fundamentally differs from other transient NVH phenomena, such as clonk or thud, which are due to impulsive actions. However, they all have their lowest common denominator in the action of contact/impact forces through lubricated contacts. Various forms of rattle have, therefore, been defined: idle rattle, drive rattle, creep rattle and over-run rattle. This paper presents a dynamic transmission model for creep rattle conditions (engaged gear at low engine RPM). The model takes into account the lubricated impact force between a gear teeth pair during a meshing cycle as well as the friction between their flanks. Hertzian contact conditions are applied to the gear pair along the torque path. Additionally, isoviscous hydrodynamic regime of lubrication is assumed for unselected (loose gear pairs) with lightly loaded impact conditions. The highly non-linear impacts induce a range of system response frequencies. These include engine order harmonics, harmonics of meshing frequency and natural frequencies related to contact stiffness. The last of these are dependent on the contact geometry and lubricant rheology. The analysis includes lubricant viscosity variation due to generated contact pressures as well as temperature. For loose gears, subject to oscillations on their retaining bearings, bearing friction is also considered.

Pinion

Contact Mechanics

Gear train

Worm drive

Non-circular gear

10.1115/detc2009-87226

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Citations (3)

Medical equipment use in children with disabilities: A descriptive survey

Journal of Pediatric Rehabilitation Medicine (2010)

Dawn E. Peredo Beth E. Davis Daniel C. Norvell Patrick C. Kelly

To investigate the use of medical equipment by children with disabilities, the reasons for use, and prescribers of equipment.A convenience sample.Referral clinic for children with developmental conditions.Caregivers of children with motor disabilities completed an interview survey for children 0-21 years.108 parents/caregivers reported 467 (mean=4.3 per patient) pieces of owned equipment. The mean age of children was 7.1 years (± 5.0), and 49% were female. The most common diagnoses were cerebral palsy (45%), 'Other' diagnoses including intellectual disability (19%), genetic abnormality (13%), spina bifida (13%), and neuromuscular diseases (7%). Survey participants described use of the following types of equipment: orthotics (82%), bath chair (37%), seating device (34%), stander (19%), augmentative communication devices (17%), walker (14%), and gait trainer (10%). Reasons for "non-use" of equipment included: outgrown (19%), not useful (14%), and child refusal (15%). Physicians were the sole prescriber for 15% of families, whereas physical or occupational therapists most commonly recommended new equipment (76%).Based on parental report, children with neuromuscular disabilities use most equipment that is medically recommended. The majority of equipment needs are identified by therapists. Pediatricians can benefit from additional expertise in the provision of medical equipment for children.

Trainer

Orthotics

10.3233/prm-2010-0138

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Citations (6)

Practical considerations for digitizing analog signals

Analytical Chemistry (1973)

Patrick C. Kelly Gary Horlick

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPractical considerations for digitizing analog signalsP. C. Kelly and Gary. HorlickCite this: Anal. Chem. 1973, 45, 3, 518–527Publication Date (Print):March 1, 1973Publication History Published online1 May 2002Published inissue 1 March 1973https://pubs.acs.org/doi/10.1021/ac60325a012https://doi.org/10.1021/ac60325a012research-articleACS PublicationsRequest reuse permissionsArticle Views203Altmetric-Citations42LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts

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10.1021/ac60325a012

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Citations (78)

Gear teeth impacts in hydrodynamic conjunctions: Idle rattle

Elsevier eBooks (2006)

O. Tangasawi Stephanos Theodossiades Homer Rahnejat Patrick C. Kelly

Flywheel

Powertrain

Idle

Gear train

10.1533/9781845692032.1.19

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Citations (0)

Exercise-induced fall in insulin: mechanism of action at the liver and effects on muscle glucose metabolism

AJP Endocrinology and Metabolism (1994)

B. A. Zinker Thomas Mohr Patrick C. Kelly K. Namdaran D. P. Bracy

To determine the importance of the fall in insulin on whole body glucose fluxes and muscle glucose metabolism during exercise, dogs ran on a motorized treadmill for 90 min at a moderate work rate with somatostatin (SRIF) infused to suppress insulin and glucagon and basal (B-INS; n = 6 dogs) or exercise-stimulated (S-INS; n = 8 dogs) insulin replacement. The fall in insulin during exercise potently stimulates glucose production at least in part by potentiating the actions of glucagon. To assess the hepatic effects of insulin in the absence of its potentiating effect on glucagon action, glucagon levels were not restored during SRIF infusion. At least 17 days before experimentation, dogs underwent surgery for chronic placement of sampling (carotid artery and femoral vein) and infusion (inferior vena cava and portal vein) catheters. Hindlimb blood flow was assessed by placement of a Doppler flow cuff on the external iliac artery. Whole body glucose production (Ra) and disappearance (Rd) were assessed with [3-3H]glucose, and hindlimb glucose uptake and metabolism were assessed with arterial-venous differences and [U-14C]glucose. Insulin levels were 69 +/- 6 and 61 +/- 7 pM at rest in B-INS and S-INS and 62 +/- 10 and 41 +/- 6 pM at 30 min of exercise. Glucose levels were clamped at euglycemic levels with an exogenous glucose infusion during rest and exercise in both groups. Exercise-induced increases in Ra, Rd, hindlimb glucose uptake, and hindlimb oxidative and nonoxidative glucose metabolism were not affected by maintenance of basil insulin levels during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Hindlimb

Carbohydrate Metabolism

10.1152/ajpendo.1994.266.5.e683

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Citations (16)

Various forms of transmission rattle in automotive powertrains

Elsevier eBooks (2010)

Patrick C. Kelly M. Menday

Powertrain

10.1533/9781845699932.2.839

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Citations (3)

A study on torsional vibration attenuation in automotive drivetrains using absorbers with smooth and non-smooth nonlinearities

Applied Mathematical Modelling (2016)

Ahmed Haris Eliot Motato Stephanos Theodossiades Homer Rahnejat Patrick C. Kelly

The automotive industry is predominantly driven by legislations on stringent emissions. This has led to the introduction of downsized engines, incorporating turbocharging to maintain output power. As downsized engines have higher combustion pressures, the resulting torsional oscillations (engine order vibrations) are of broadband nature with an increasing severity, which affect noise and vibration response of the drive train system. Palliative devices, such as clutch pre-dampers and dual mass flywheel have been used to mitigate the effect of transmitted engine torsional oscillations. Nevertheless, the effectiveness of these palliative measures is confined to a narrow band of response frequencies. The nonlinear targeted energy transfer is a promising approach to study vibration mitigation within a broader range of frequencies, using nonlinear vibration absorbers (or nonlinear energy sinks – NESs). These devices would either redistribute vibration energy within the modal space of the primary structure, thus dissipating the vibrational energy more efficiently through structural damping, or passively absorb and locally dissipate a part of this energy (in a nearly irreversible manner) from the primary structure. The absence of a linear resonance frequency of an NES, enables its broadband operation (in contrast to the narrowband operation of current linear tuned mass dampers). Parametric studies are reported to determine the effectiveness of various smooth or non-smooth nonlinear stiffness characteristics of such absorbers. A reduced drivetrain model, incorporating single and multiple absorber attachments is used and comparison of the predictions to numerical integrations proves its efficacy.

Drivetrain

Tuned mass damper

Flywheel

Chassis

Torsional Vibration

Mistuning

10.1016/j.apm.2016.09.030

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Citations (75)

Helminths of the Cotton Rat in Southern Virginia, with Comments on the Sex Ratios of Parasitic Nematode Populations

The American Midland Naturalist (1974)

Arthur J. Seidenberg Patrick C. Kelly Eileen R. Lubin John D. Buffington

Thirty-eight cotton rats, Sigmodon hispidus, were collected in Virginia and examined for their helminth fauna. The cestodes recovered were: Choanotaenia nebraskensis (8% incidence), Hymenolepis diminuta (18%) and Raillietina bakeri (18%) from the intestine, and larval Taenia taeniaeformis (16%) from the liver. This is the first report of C. nebraskensis from the cotton rat. The nematodes found were Longistriata adunca (76%) from the intestine and Mastophorus muris (42%) from the stomach. The heaviest infections were produced by L. adunca (41 worms per infected host) and R. bakeri (21 worms per infected host). Twenty hosts harbored two or more species of worms. Mastophorus muris and C. nebraskensis were more common in female than male hosts. The sex ratio of the 1201 L. adunca collected was determined. Young cotton rats have a 1: 1 female worm to male worm sex ratio. Older hosts have more female than male worms. INTRODUCTION The helminth fauna of the cotton rat, Sigmodon hispidus, is relatively well known. Baylis (1945) and Melvin and Chandler (1950) published species lists of cotton rat helminths from the southern United States and Florida and Texas, respectively. Harkema and Kartman (1948) compared the helminth fauna and ectoparasites of cotton rats from North Carolina and Georgia. They studied the general incidence and intensity of infection, seasonal variation and other host-parasite relationships. Hugghins (1951) surveyed and compared the helminths and ectoparasites of roof rats and cotton rats in Texas. Lanier (1951) studied the helminths of Sigmodon hispidus in Florida. Recently, Kinsella (1974) compared the helminths of cotton rats from saltwater and freshwater marshes in northern Florida. He also included a checklist of all the helminths known from the cotton

10.2307/2424297

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Citations (15)

Ghrelin levels in young children with Prader-Willi syndrome

The Journal of Pediatrics (2006)

Christine Erdie-Lalena Vanja A. Holm Patrick C. Kelly R. Scott Frayo David E. Cummings

10.1016/j.jpeds.2006.04.011

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Citations (57)