Science.gov

Sample records for locomotive operation

  1. Bioinspired laser-operated molecular locomotive.

    PubMed

    Wang, Zhisong

    2004-09-01

    Biomotors kinesin and dynein show us that robust track-walking is possible down to molecular scale. Here I design a laser-powered molecular locomotive that is able to do that on an easily constructed track. The core of the machine is its work cycle that periodically converts optical energy into mechanical work, which is further rectified into processive, directional motion. Thus the molecular locomotive is essentially beyond the famous design of molecular shuttles. Under automated laser operation, the locomotive can move a few mum per second comparable to its biological counterparts. However, this artificial motor is capable of conveniently switchable, dual directional motion in contrast to common unidirectionality of biomotors. The locomotive is also different from the big category of Brownian motors in the sense that move of the locomotive is not a result of biasing pre-existing fluctuations, rather it is directly and decisively driven by optomechanical strokes of the work cycle, generating a pulling force ten times greater than those of biomotors. Being a novel type of molecular motor as well as a powerful molecular engine, this machine will potentially enable automatic, forceful delivery of molecular building blocks with nanometer accuracy. Well within reach of established techniques, its implementation will be a significant advance in nanoscience and nanotechnology.

  2. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Operation standards (stationary locomotives at 30 meters). 210.31 Section 210.31 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.31 Operation standards (stationary locomotives at 30 meters). (a)...

  3. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Operation standards (stationary locomotives at 30 meters). 210.31 Section 210.31 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.31 Operation standards (stationary locomotives at 30 meters). (a)...

  4. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.29 Operation standards (moving locomotives and rail cars). The operation standards for the noise emission levels of moving locomotives, rail cars, or consists...

  5. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.29 Operation standards (moving locomotives and rail cars). The operation standards for the noise emission levels of moving locomotives, rail cars, or consists...

  6. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.29 Operation standards (moving locomotives and rail cars). The operation standards for the noise emission levels of moving locomotives, rail cars, or consists...

  7. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.29 Operation standards (moving locomotives and rail cars). The operation standards for the noise emission levels of moving locomotives, rail cars, or consists...

  8. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued... REGULATIONS Inspection and Testing § 210.29 Operation standards (moving locomotives and rail cars). The operation standards for the noise emission levels of moving locomotives, rail cars, or consists...

  9. 49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands,...

  10. 49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands,...

  11. 49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands,...

  12. 49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands,...

  13. 49 CFR 210.33 - Operation standards (switcher locomotives, load cell test stands, car coupling operations, and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... cell test stands, car coupling operations, and retarders). 210.33 Section 210.33 Transportation Other... (switcher locomotives, load cell test stands, car coupling operations, and retarders). (a) Measurement on receiving property of the noise emission levels from switcher locomotives, load cell test stands,...

  14. 49 CFR 236.1047 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control Systems § 236.1047 Training specific to locomotive... any locomotive engineer or other person who participates in the operation of a train in train...

  15. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... locomotive has attained the normal cooling water operating temperature as prescribed by the locomotive... prescribed in paragraph (a)(2) of this section, the A-weighted sound level reading in decibels shall be... A-weighted sound level reading in decibels that is observed during the 30-second period of...

  16. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... locomotive has attained the normal cooling water operating temperature as prescribed by the locomotive... prescribed in paragraph (a)(2) of this section, the A-weighted sound level reading in decibels shall be... A-weighted sound level reading in decibels that is observed during the 30-second period of...

  17. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... locomotive has attained the normal cooling water operating temperature as prescribed by the locomotive... prescribed in paragraph (a)(2) of this section, the A-weighted sound level reading in decibels shall be... A-weighted sound level reading in decibels that is observed during the 30-second period of...

  18. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control Systems § 236.1006 Equipping locomotives operating in PTC territory. (a) Except as provided in paragraph (b) of this section, each train operating on any...

  19. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control Systems § 236.1006 Equipping locomotives operating in PTC territory. (a) Except as provided in paragraph (b) of this section, each train operating on any...

  20. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control Systems § 236.1006 Equipping locomotives operating in PTC territory. (a) Except as provided in paragraph (b) of this section, each train operating on any...

  1. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control Systems § 236.1006 Equipping locomotives operating in PTC territory. (a) Except as provided in paragraph (b) of this section, each train operating on any...

  2. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Positive Train Control Systems § 236.1006 Equipping locomotives operating in PTC territory. (a) Except as provided in paragraph (b) of this section, each train operating on any...

  3. 49 CFR 1242.67 - Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 9 2012-10-01 2012-10-01 false Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive power; operating switches...; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive...

  4. 49 CFR 1242.67 - Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive power; operating switches...; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive...

  5. 49 CFR 1242.67 - Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 9 2013-10-01 2013-10-01 false Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive power; operating switches...; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive...

  6. 49 CFR 1242.67 - Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive power; operating switches... SERVICE FOR RAILROADS 1 Operating Expenses-Transportation § 1242.67 Switch crews; controlling...

  7. 49 CFR 1242.67 - Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Switch crews; controlling operations; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive power; operating switches... SERVICE FOR RAILROADS 1 Operating Expenses-Transportation § 1242.67 Switch crews; controlling...

  8. 49 CFR 236.566 - Locomotive of each train operating in train stop, train control or cab signal territory; equipped.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Locomotive of each train operating in train stop... TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control...

  9. 49 CFR 236.566 - Locomotive of each train operating in train stop, train control or cab signal territory; equipped.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive of each train operating in train stop... TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control...

  10. 49 CFR 236.566 - Locomotive of each train operating in train stop, train control or cab signal territory; equipped.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Locomotive of each train operating in train stop... TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control...

  11. 49 CFR 236.566 - Locomotive of each train operating in train stop, train control or cab signal territory; equipped.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Locomotive of each train operating in train stop... TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control...

  12. 49 CFR 236.566 - Locomotive of each train operating in train stop, train control or cab signal territory; equipped.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Locomotive of each train operating in train stop... TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION, INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control...

  13. Feasibility study for SOFC-GT hybrid locomotive power part II. System packaging and operating route simulation

    NASA Astrophysics Data System (ADS)

    Martinez, Andrew S.; Brouwer, Jacob; Samuelsen, G. Scott

    2012-09-01

    This work assesses the feasibility of Solid Oxide Fuel Cell-Gas Turbine (SOFC-GT) hybrid power systems for use as the prime mover in freight locomotives. The available space in a diesel engine-powered locomotive is compared to that required for an SOFC-GT system, inclusive of fuel processing systems necessary for the SOFC-GT. The SOFC-GT space requirement is found to be similar to current diesel engines, without consideration of the electrical balance of plant. Preliminary design of the system layout within the locomotive is carried out for illustration. Recent advances in SOFC technology and implications of future improvements are discussed as well. A previously-developed FORTRAN model of an SOFC-GT system is then augmented to simulate the kinematics and power notching of a train and its locomotives. The operation of the SOFC-GT-powered train is investigated along a representative route in Southern California, with simulations presented for diesel reformate as well as natural gas reformate and hydrogen as fuels. Operational parameters and difficulties are explored as are comparisons of expected system performance to modern diesel engines. It is found that even in the diesel case, the SOFC-GT system provides significant savings in fuel and CO2 emissions, making it an attractive option for the rail industry.

  14. 76 FR 2199 - Locomotive Safety Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-12

    ... analysis for new locomotive electronic systems. FRA believes this proposal will modernize and improve its..., railroad track, signal systems, communications, rolling stock, operating practices, passenger train... requirements for brake, draft, suspension, and electrical systems, and locomotive cabs; and locomotive...

  15. Data on the noise vibrations of modern traction locomotives. [auditory effects on diesel engine operators

    NASA Technical Reports Server (NTRS)

    Paslaru, V.; Popescu, A.; Vrasti, R.

    1974-01-01

    A survey is presented of data on noise and vibration sources in modern locomotives and their influence on engine drivers. An attempt is made hierarchize noise and vibration sources in terms of importance and to correlate the noise level with the influence of noise on the engine drivers' organ of hearing. Some possible recommendations are outlined for reducing the level of these noxae in order to improve the acoustic comfort of engine drivers.

  16. The effects of operating conditions on particulate matter exhaust from diesel locomotive engines.

    PubMed

    Park, Duckshin; Yoon, Younghun; Kwon, Soon-Bark; Jeong, Wootae; Cho, Youngmin; Lee, Kiyoung

    2012-03-01

    Numerous reports have shown that fine particulates threaten human health. Since their health impact is associated with both mass and number concentrations, it is necessary to evaluate the emission standards for particulate mass accordingly. This study examined the particulate matter characteristics of diesel locomotive engine exhaust at various engine ratings. Diesel engine exhaust was collected via a dilution tunnel and the concentration and size distribution of fine particles were measured by a scanning mobility particle sizer. Exhaust gasses were measured simultaneously by a stack sampler. The maximum carbon monoxide emission was reached at 59% of the maximum rating, after which emissions decreased. The particle count median diameter increased with the engine rating, until a maximum was reached at 40% of the maximum rating. Most exhaust particles were nanoparticles with the nuclei mode range, a particle diameter (D(P))<50 nm. The increase in particles with the accumulation mode range, 50

  17. Optimizing Locomotion

    NASA Astrophysics Data System (ADS)

    Hosoi, Anette

    2006-11-01

    In this talk we will discuss two optimization topics related to low Reynolds number locomotion: optimal stroke patterns in linked swimmers and optimal fluid material properties in adhesive locomotion. In contrast to many optimization problems, we do not consider geometry, rather we optimize the swimming kinematics or fluid material properties for a given geometrical configuration. In the first case, we begin by optimizing stroke patterns for Purcell's 3-link swimmer. We model the swimmer as a jointed chain of three slender links moving in an inertialess flow. The swimmer is optimized for both efficiency and speed. In the second case, we analyze the adhesive locomotion used by common gastropods such as snails and slugs. Such organisms crawl on a solid substrate by propagating muscular waves of shear stress on a viscoelastic mucus. Using a simple mechanical model, we derive criteria for favorable fluid material properties to lower the energetic cost of locomotion.

  18. 49 CFR 236.927 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... SYSTEMS, DEVICES, AND APPLIANCES Standards for Processor-Based Signal and Train Control Systems § 236.927... data to, the system, such as consist data, and the role of that function in the safe operation of...

  19. 40 CFR 201.11 - Standard for locomotive operation under stationary conditions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... before December 31, 1979, which produces A-weighted sound levels in excess of 93 dB at any throttle... produces A-weighted sound levels in excess of 87 dB at any throttle setting except idle, when operated... produces A-weighted sound levels in excess of 87 dB at any throttle setting except idle, when...

  20. 40 CFR 201.12 - Standard for locomotive operation under moving conditions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... under moving conditions. 201.12 Section 201.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... moving conditions. (a) Commencing December 31, 1976, no carrier subject to this regulation may operate... 96 dB when moving at any time or under any condition of grade, load, acceleration, or...

  1. 40 CFR 201.12 - Standard for locomotive operation under moving conditions.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... moving conditions. 201.12 Section 201.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... moving conditions. (a) Commencing December 31, 1976, no carrier subject to this regulation may operate... 96 dB when moving at any time or under any condition of grade, load, acceleration, or...

  2. 40 CFR 201.12 - Standard for locomotive operation under moving conditions.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... under moving conditions. 201.12 Section 201.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... moving conditions. (a) Commencing December 31, 1976, no carrier subject to this regulation may operate... 96 dB when moving at any time or under any condition of grade, load, acceleration, or...

  3. 40 CFR 201.12 - Standard for locomotive operation under moving conditions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... under moving conditions. 201.12 Section 201.12 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... moving conditions. (a) Commencing December 31, 1976, no carrier subject to this regulation may operate... 96 dB when moving at any time or under any condition of grade, load, acceleration, or...

  4. Torsional locomotion

    PubMed Central

    Bigoni, D.; Dal Corso, F.; Misseroni, D.; Bosi, F.

    2014-01-01

    One edge of an elastic rod is inserted into a friction-less and fitting socket head, whereas the other edge is subjected to a torque, generating a uniform twisting moment. It is theoretically shown and experimentally proved that, although perfectly smooth, the constraint realizes an expulsive axial force on the elastic rod, which amount is independent of the shape of the socket head. The axial force explains why screwdrivers at high torque have the tendency to disengage from screw heads and demonstrates torsional locomotion along a perfectly smooth channel. This new type of locomotion finds direct evidence in the realization of a ‘torsional gun’, capable of transforming torque into propulsive force. PMID:25383038

  5. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  6. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  7. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  8. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  9. 40 CFR 201.24 - Procedures for measurement at a 30 meter (100 feet) distance of the noise from locomotive and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... meter (100 feet) distance of the noise from locomotive and rail car operations and locomotive load cell... locomotive and rail car operations and locomotive load cell test stands. (a) Microphone positions. (1) The... measured. (b) Stationary locomotive and locomotive load cell test stand tests. (1) For...

  10. Union Pacific Railroad`s LNG locomotive test program

    SciTech Connect

    Grimaila, B.

    1995-12-31

    Union Pacific Railroad is testing LNG in six locomotives through 1997 to determine if the liquefied natural gas technology is right for them. Two of the six LNG test locomotives are switch, or yard, locomotives. These 1,350 horsepower locomotives are the industry`s first locomotives totally fueled by natural gas. They`re being tested in the yard in the Los Angeles area. The other four locomotives are long-haul locomotives fueled by two tenders. These units are duel-fueled, operating on a mixture of LNG and diesel and are being tested primarily on the Los Angeles to North Platte, Nebraska corridor. All the information concerning locomotive emissions, locomotive performance, maintenance requirements, the overall LNG system design and the economic feasibility of the project will be analyzed to determine if UPR should expand, or abandon, the LNG technology.

  11. 77 FR 21311 - Locomotive Safety Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-09

    ... existing locomotive safety needs and recommending consideration of specific actions useful to advance the...-diagnostic technology and advanced computer control, and that the locomotives were designed by the... actions useful to advance the safety of rail operations. The RSAC established the Working Group to...

  12. Operant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans

    PubMed Central

    Makihara, Yukiko; Segal, Richard L.; Wolpaw, Jonathan R.

    2014-01-01

    In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes. In rats and people with incomplete spinal cord injury (SCI), soleus H-reflex operant conditioning can improve locomotion. We studied in normal humans the impact of soleus H-reflex down-conditioning on medial (MG) and lateral gastrocnemius (LG) H-reflexes and on locomotion. Subjects completed 6 baseline and 30 conditioning sessions. During conditioning trials, the subject was encouraged to decrease soleus H-reflex size with the aid of visual feedback. Every sixth session, MG and LG H-reflexes were measured. Locomotion was assessed before and after conditioning. In successfully conditioned subjects, the soleus H-reflex decreased 27.2%. This was the sum of within-session (task dependent) adaptation (13.2%) and across-session (long term) change (14%). The MG H-reflex decreased 14.5%, due mainly to task-dependent adaptation (13.4%). The LG H-reflex showed no task-dependent adaptation or long-term change. No consistent changes were detected across subjects in locomotor H-reflexes, EMG activity, joint angles, or step symmetry. Thus, in normal humans, soleus H-reflex down-conditioning does not induce long-term changes in MG/LG H-reflexes and does not change locomotion. In these subjects, task-dependent adaptation of the soleus H-reflex is greater than it is in people with SCI, whereas long-term change is less. This difference from results in people with SCI is consistent with the fact that long-term change is beneficial in people with SCI, since it improves locomotion. In contrast, in normal subjects, long-term change is not beneficial and may necessitate compensatory plasticity to preserve satisfactory locomotion. PMID:24944216

  13. Operant conditioning of the soleus H-reflex does not induce long-term changes in the gastrocnemius H-reflexes and does not disturb normal locomotion in humans.

    PubMed

    Makihara, Yukiko; Segal, Richard L; Wolpaw, Jonathan R; Thompson, Aiko K

    2014-09-15

    In normal animals, operant conditioning of the spinal stretch reflex or the H-reflex has lesser effects on synergist muscle reflexes. In rats and people with incomplete spinal cord injury (SCI), soleus H-reflex operant conditioning can improve locomotion. We studied in normal humans the impact of soleus H-reflex down-conditioning on medial (MG) and lateral gastrocnemius (LG) H-reflexes and on locomotion. Subjects completed 6 baseline and 30 conditioning sessions. During conditioning trials, the subject was encouraged to decrease soleus H-reflex size with the aid of visual feedback. Every sixth session, MG and LG H-reflexes were measured. Locomotion was assessed before and after conditioning. In successfully conditioned subjects, the soleus H-reflex decreased 27.2%. This was the sum of within-session (task dependent) adaptation (13.2%) and across-session (long term) change (14%). The MG H-reflex decreased 14.5%, due mainly to task-dependent adaptation (13.4%). The LG H-reflex showed no task-dependent adaptation or long-term change. No consistent changes were detected across subjects in locomotor H-reflexes, EMG activity, joint angles, or step symmetry. Thus, in normal humans, soleus H-reflex down-conditioning does not induce long-term changes in MG/LG H-reflexes and does not change locomotion. In these subjects, task-dependent adaptation of the soleus H-reflex is greater than it is in people with SCI, whereas long-term change is less. This difference from results in people with SCI is consistent with the fact that long-term change is beneficial in people with SCI, since it improves locomotion. In contrast, in normal subjects, long-term change is not beneficial and may necessitate compensatory plasticity to preserve satisfactory locomotion.

  14. Electrokinetic Locomotion

    NASA Astrophysics Data System (ADS)

    Moran, Jeffrey Lawrence

    occurring in the interfacial layer near the particle/solution interface, which play a key role in the locomotion. The model enables one to understand how the rods' motion depends on the properties of their environment, such as hydrogen peroxide concentration, solution electrical conductivity, and solution viscosity. The numerical simulations are complemented with a scaling analysis based on the governing equations, which makes definite, verifiable predictions of these dependences. One of the most important trends that has been observed experimentally is the significant decrease in speed induced by adding sub-millimolar concentrations of inert electrolyte. It is important to understand the physical reasons for the electrolyte-induced speed decrease, in order to know whether it is fundamental to this propulsion mechanism, or if there is some feasible means to circumvent it. Successful completion of this research will result in an improved understanding of the capabilities, as well as the risks and limits of applicability, of the bimetallic nanomotors for applications in nanotechnology and nanomedicine. Potential applications of the rods include the targeted delivery of drugs in the human body, sensing of chemical impurities in drinking water, and as engines to drive fabrication of microscale structures.

  15. Railroad and locomotive technology roadmap.

    SciTech Connect

    Stodolsky, F.; Gaines, L.; Energy Systems

    2003-02-24

    Railroads are important to the U.S. economy. They transport freight efficiently, requiring less energy and emitting fewer pollutants than other modes of surface transportation. While the railroad industry has steadily improved its fuel efficiency--by 16% over the last decade--more can, and needs to, be done. The ability of locomotive manufacturers to conduct research into fuel efficiency and emissions reduction is limited by the small number of locomotives manufactured annually. Each year for the last five years, the two North American locomotive manufacturers--General Electric Transportation Systems and the Electro-Motive Division of General Motors--have together sold about 800 locomotives in the United States. With such a small number of units over which research costs can be spread, outside help is needed to investigate all possible ways to reduce fuel usage and emissions. Because fuel costs represent a significant portion of the total operating costs of a railroad, fuel efficiency has always been an important factor in the design of locomotives and in the operations of a railroad. However, fuel efficiency has recently become even more critical with the introduction of strict emission standards by the U.S. Environmental Protection Agency, to be implemented in stages (Tiers 0, 1, and 2) between 2000 and 2005. Some of the technologies that could be employed to meet the emission standards may negatively affect fuel economy--by as much as 10-15% when emissions are reduced to Tier 1 levels. Lowering fuel economy by that magnitude would have a serious impact on the cost to the consumer of goods shipped by rail, on the competitiveness of the railroad industry, and on this country's dependence on foreign oil. Clearly, a joint government/industry R&D program is needed to help catalyze the development of advanced technologies that will substantially reduce locomotive engine emissions while also improving train system energy efficiency. DOE convened an industry

  16. Dynamically Stable Legged Locomotion.

    DTIC Science & Technology

    1983-01-27

    forces to be generated at the foot. A finite state sequencer provides the glue that synchronizes the actions uf the three controllers to the ongoing...V., ’Fittlc,1R. Engineering of locomotion in gorilla and man. In Control ofPosau,e and Locomotion, R.B. Stein, K.G. Pearson, R.S. Smith, J.11. Redford

  17. Job Grading Standard for Locomotive Engineer WG-6004.

    ERIC Educational Resources Information Center

    Civil Service Commission, Washington, DC. Bureau of Policies and Standards.

    The standard is used to grade the nonsupervisory work of operating all types of locomotives and trains to transport supplies, equipment, conveyances, and personnel. The work involves skill in operating locomotives under various conditions, and knowledge of the layout of a track system and the safety, signalling, and track use requirements or…

  18. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  19. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  20. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  1. 40 CFR 1033.650 - Incidental use exemption for Canadian and Mexican locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... and Mexican locomotives. 1033.650 Section 1033.650 Protection of Environment ENVIRONMENTAL PROTECTION... Provisions § 1033.650 Incidental use exemption for Canadian and Mexican locomotives. You may ask us to exempt... exempt locomotives that will not operate more than 25 miles from the border and will operate in...

  2. 40 CFR 1033.650 - Incidental use exemption for Canadian and Mexican locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... and Mexican locomotives. 1033.650 Section 1033.650 Protection of Environment ENVIRONMENTAL PROTECTION... Provisions § 1033.650 Incidental use exemption for Canadian and Mexican locomotives. You may ask us to exempt... exempt locomotives that will not operate more than 25 miles from the border and will operate in...

  3. 40 CFR 1033.650 - Incidental use exemption for Canadian and Mexican locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... and Mexican locomotives. 1033.650 Section 1033.650 Protection of Environment ENVIRONMENTAL PROTECTION... Provisions § 1033.650 Incidental use exemption for Canadian and Mexican locomotives. You may ask us to exempt... exempt locomotives that will not operate more than 25 miles from the border and will operate in...

  4. 40 CFR 1033.650 - Incidental use exemption for Canadian and Mexican locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... and Mexican locomotives. 1033.650 Section 1033.650 Protection of Environment ENVIRONMENTAL PROTECTION... Provisions § 1033.650 Incidental use exemption for Canadian and Mexican locomotives. You may ask us to exempt... exempt locomotives that will not operate more than 25 miles from the border and will operate in...

  5. 40 CFR 1033.650 - Incidental use exemption for Canadian and Mexican locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... and Mexican locomotives. 1033.650 Section 1033.650 Protection of Environment ENVIRONMENTAL PROTECTION... Provisions § 1033.650 Incidental use exemption for Canadian and Mexican locomotives. You may ask us to exempt... exempt locomotives that will not operate more than 25 miles from the border and will operate in...

  6. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  7. 40 CFR 201.16 - Standard for locomotive load cell test stands.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Standard for locomotive load cell test... Interstate Rail Carrier Operations Standards § 201.16 Standard for locomotive load cell test stands. (a) Effective January 15, 1984, no carrier subject to this reguation shall operate locomotive load cell...

  8. Track train dynamics analysis and test program: Locomotive dynamic characterization summary

    NASA Technical Reports Server (NTRS)

    Berry, R. L.

    1982-01-01

    Locomotive mechanical characteristics, track perturbations, and operational characteristics involving experimentally determined suspension system parameters are analyzed. Suspension bearings, shock absorbers, pads, and two- and three- axle trucks are comparatively evaluated with respect to locomotive design.

  9. Track train dynamics analysis and test program: Methodology development for the derailment safety analysis of six-axle locomotives

    NASA Technical Reports Server (NTRS)

    Marcotte, P. P.; Mathewson, K. J. R.

    1982-01-01

    The operational safety of six axle locomotives is analyzed. A locomotive model with corresponding data on suspension characteristics, a method of track defect characterization, and a method of characterizing operational safety are used. A user oriented software package was developed as part of the methodology and was used to study the effect (on operational safety) of various locomotive parameters and operational conditions such as speed, tractive effort, and track curvature. The operational safety of three different locomotive designs was investigated.

  10. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  11. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  12. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  13. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  14. 49 CFR 229.213 - Locomotive manufacturing information.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive manufacturing information. 229.213 Section 229.213 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... Design Requirements § 229.213 Locomotive manufacturing information. (a) Each railroad operating...

  15. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... of the air entering the engine after any charge air cooling to within 5 °C of the typical intake manifold air temperature when the engine is operated in the locomotive under similar ambient conditions....

  16. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... of the air entering the engine after any charge air cooling to within 5 °C of the typical intake manifold air temperature when the engine is operated in the locomotive under similar ambient conditions....

  17. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... of the air entering the engine after any charge air cooling to within 5 °C of the typical intake manifold air temperature when the engine is operated in the locomotive under similar ambient conditions....

  18. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... of the air entering the engine after any charge air cooling to within 5 °C of the typical intake manifold air temperature when the engine is operated in the locomotive under similar ambient conditions....

  19. 40 CFR 1033.515 - Discrete-mode steady-state emission tests of locomotives and locomotive engines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Test... of the air entering the engine after any charge air cooling to within 5 °C of the typical intake manifold air temperature when the engine is operated in the locomotive under similar ambient conditions....

  20. The Human Central Pattern Generator for Locomotion.

    PubMed

    Minassian, Karen; Hofstoetter, Ursula S; Dzeladini, Florin; Guertin, Pierre A; Ijspeert, Auke

    2017-03-01

    The ability of dedicated spinal circuits, referred to as central pattern generators (CPGs), to produce the basic rhythm and neural activation patterns underlying locomotion can be demonstrated under specific experimental conditions in reduced animal preparations. The existence of CPGs in humans is a matter of debate. Equally elusive is the contribution of CPGs to normal bipedal locomotion. To address these points, we focus on human studies that utilized spinal cord stimulation or pharmacological neuromodulation to generate rhythmic activity in individuals with spinal cord injury, and on neuromechanical modeling of human locomotion. In the absence of volitional motor control and step-specific sensory feedback, the human lumbar spinal cord can produce rhythmic muscle activation patterns that closely resemble CPG-induced neural activity of the isolated animal spinal cord. In this sense, CPGs in humans can be defined by the activity they produce. During normal locomotion, CPGs could contribute to the activation patterns during specific phases of the step cycle and simplify supraspinal control of step cycle frequency as a feedforward component to achieve a targeted speed. Determining how the human CPGs operate will be essential to advance the theory of neural control of locomotion and develop new locomotor neurorehabilitation paradigms.

  1. Fuelcell Prototype Locomotive

    SciTech Connect

    David L. Barnes

    2007-09-28

    An international industry-government consortium is developing a fuelcell hybrid switcher locomotive for commercial railway applications and power-to-grid generation applications. The current phase of this on-going project addresses the practicalities of on-board hydrogen storage, fuelcell technology, and hybridity, all with an emphasis on commercially available products. Through practical evaluation using designs from Vehicle Projects’ Fuelcell-Powered Underground Mine Loader Project, the configuration of the fuelcell switcher locomotive changed from using metal-hydride hydrogen storage and a pure fuelcell power plant to using compressed hydrogen storage, a fuelcell-battery hybrid power plant, and fuelcell stack modules from Ballard Power Systems that have been extensively used in the Citaro bus program in Europe. The new overall design will now use a RailPower battery hybrid Green Goat™ as the locomotive platform. Keeping the existing lead-acid batteries, we will replace the 205 kW diesel gen-set with 225 kW of net fuelcell power, remove the diesel fuel tank, and place 14 compressed hydrogen cylinders, capable of storing 70 kg of hydrogen at 350 bar, on the roof. A detailed design with associated CAD models will allow a complete build of the fuelcell-battery hybrid switcher locomotive in the next funded phase.

  2. Locomotive Syndrome: Definition and Management.

    PubMed

    Nakamura, Kozo; Ogata, Toru

    Locomotive syndrome is a condition of reduced mobility due to impairment of locomotive organs. Since upright bipedal walking involves minutely controlled movement patterns, impairment of any aspect of the locomotive organs has the potential to adversely affect it. In addition to trauma, chronic diseases of the locomotive organs, which progress with repeated bouts of acute exacerbations, are common causes of the locomotive syndrome. In Japan's super-aging society, many people are likely to experience locomotive syndrome in the later part of their lives. Exercise intervention is effective in improving motor function, but because the subjects are elderly people with significant degenerative diseases of the locomotor organs, caution should be taken in choosing the type and intensity of exercise. The present review discusses the definition, current burden, diagnosis and interventions pertaining to the locomotive syndrome. The concept and measures are spreading throughout Japan as one of the national health policy targets.

  3. Advanced robot locomotion.

    SciTech Connect

    Neely, Jason C.; Sturgis, Beverly Rainwater; Byrne, Raymond Harry; Feddema, John Todd; Spletzer, Barry Louis; Rose, Scott E.; Novick, David Keith; Wilson, David Gerald; Buerger, Stephen P.

    2007-01-01

    This report contains the results of a research effort on advanced robot locomotion. The majority of this work focuses on walking robots. Walking robot applications include delivery of special payloads to unique locations that require human locomotion to exo-skeleton human assistance applications. A walking robot could step over obstacles and move through narrow openings that a wheeled or tracked vehicle could not overcome. It could pick up and manipulate objects in ways that a standard robot gripper could not. Most importantly, a walking robot would be able to rapidly perform these tasks through an intuitive user interface that mimics natural human motion. The largest obstacle arises in emulating stability and balance control naturally present in humans but needed for bipedal locomotion in a robot. A tracked robot is bulky and limited, but a wide wheel base assures passive stability. Human bipedal motion is so common that it is taken for granted, but bipedal motion requires active balance and stability control for which the analysis is non-trivial. This report contains an extensive literature study on the state-of-the-art of legged robotics, and it additionally provides the analysis, simulation, and hardware verification of two variants of a proto-type leg design.

  4. Compliant Synergies in Locomotion

    NASA Astrophysics Data System (ADS)

    Travers, Matthew; Choset, Howie; Goldman @ Georgia Tech. Physics Department Collaboration

    Biological systems appear to have natural mechanisms that allow them to readily compensate for unexpected environmental variations when compared to their mechanical (i.e., robotic) counterparts. We hypothesize that the basis for this discrepancy is almost innate: what biology appears to be born with, built-in mechanisms for coordinating their many degrees of freedom, we struggle to ``program.'' We therefore look toward biology for inspiration. In particular, we are interested in kinematic synergies, low-dimensional representations that explicitly encode the underlying structure of how systems coordinate their internal degrees of freedom to achieve high-level tasks. In this work, we derive parametric representations of kinematic synergies and present a new compliant locomotion control framework that enables the parameters to be directly controlled in response to external disturbances. We present results of this framework implemented on two separate platforms, a snake-like and hexapod robot. Our results show that, using synergies, the locomotion control of these very different systems can be reduced to simple, extremely capable, and common forms, thus offering new insights into both robotic as well as biological locomotion in complex terrains.

  5. The role of locomotion in psychological development

    PubMed Central

    Anderson, David I.; Campos, Joseph J.; Witherington, David C.; Dahl, Audun; Rivera, Monica; He, Minxuan; Uchiyama, Ichiro; Barbu-Roth, Marianne

    2013-01-01

    The psychological revolution that follows the onset of independent locomotion in the latter half of the infant's first year provides one of the best illustrations of the intimate connection between action and psychological processes. In this paper, we document some of the dramatic changes in perception-action coupling, spatial cognition, memory, and social and emotional development that follow the acquisition of independent locomotion. We highlight the range of converging research operations that have been used to examine the relation between locomotor experience and psychological development, and we describe recent attempts to uncover the processes that underlie this relation. Finally, we address three important questions about the relation that have received scant attention in the research literature. These questions include: (1) What changes in the brain occur when infants acquire experience with locomotion? (2) What role does locomotion play in the maintenance of psychological function? (3) What implications do motor disabilities have for psychological development? Seeking the answers to these questions can provide rich insights into the relation between action and psychological processes and the general processes that underlie human development. PMID:23888146

  6. Locomotion in the decerebrate stingray.

    PubMed

    Leonard, R B; Rudomín, P; Droge, M H; Grossman, A E; Willis, W D

    1979-10-01

    Stingrays swim with an active elevation-depression sequence of the pectoral fin resembling an extension-flexion sequence. During forward locomotion this sequence passes caudally along the pectoral fin. Immediately following high decerebration, stingrays are capable of locomotion, and the pattern of muscle activity closely resembles that of intact animals. Spontaneous and midbrain evoked rhythmic motoneuron discharges can be recorded in paralyzed decerebrated animals. In contrast to dogfish sharks, stringrays with high spinal transections do not locomote.

  7. Locomotion: Dealing with friction

    PubMed Central

    Radhakrishnan, V.

    1998-01-01

    To move on land, in water, or in the air, even at constant speed and at the same level, always requires an expenditure of energy. The resistance to motion that has to be overcome is of many different kinds depending on size, speed, and the characteristics of the medium, and is a fascinating subject in itself. Even more interesting are nature’s stratagems and solutions toward minimizing the effort involved in the locomotion of different types of living creatures, and humans’ imitations and inventions in an attempt to do at least as well. PMID:9576902

  8. Forcing contact inhibition of locomotion.

    PubMed

    Roycroft, Alice; Mayor, Roberto

    2015-07-01

    Contact inhibition of locomotion drives a variety of biological phenomenon, from cell dispersion to collective cell migration and cancer invasion. New imaging techniques have allowed contact inhibition of locomotion to be visualised in vivo for the first time, helping to elucidate some of the molecules and forces involved in this phenomenon.

  9. Locomotion in caterpillars.

    PubMed

    van Griethuijsen, L I; Trimmer, B A

    2014-08-01

    Most species of caterpillar move around by inching or crawling. Their ability to navigate in branching three-dimensional structures makes them particularly interesting biomechanical subjects. The mechanism of inching has not been investigated in detail, but crawling is now well understood from studies on caterpillar neural activity, dynamics and structural mechanics. Early papers describe caterpillar crawling as legged peristalsis, but recent work suggests that caterpillars use a tension-based mechanism that helps them to exploit arboreal niches. Caterpillars are not obligate hydrostats but instead use their strong grip to the substrate to transmit forces, in effect using their environment as a skeleton. In addition, the gut which accounts for a substantial part of the caterpillar's weight, moves independently of the body wall during locomotion and may contribute to crawling dynamics. Work-loop analysis of caterpillar muscles shows that they are likely to act both as actuators and energy dissipaters during crawling. Because caterpillar tissues are pseudo-elastic, and locomotion involves large body deformations, moving is energetically inefficient. Possession of a soft body benefits caterpillars by allowing them to grow quickly and to access remote food sources safely.

  10. Locomotion control of hybrid cockroach robots

    PubMed Central

    Sanchez, Carlos J.; Chiu, Chen-Wei; Zhou, Yan; González, Jorge M.; Vinson, S. Bradleigh; Liang, Hong

    2015-01-01

    Natural systems retain significant advantages over engineered systems in many aspects, including size and versatility. In this research, we develop a hybrid robotic system using American (Periplaneta americana) and discoid (Blaberus discoidalis) cockroaches that uses the natural locomotion and robustness of the insect. A tethered control system was firstly characterized using American cockroaches, wherein implanted electrodes were used to apply an electrical stimulus to the prothoracic ganglia. Using this approach, larger discoid cockroaches were engineered into a remotely controlled hybrid robotic system. Locomotion control was achieved through electrical stimulation of the prothoracic ganglia, via a remotely operated backpack system and implanted electrodes. The backpack consisted of a microcontroller with integrated transceiver protocol, and a rechargeable battery. The hybrid discoid roach was able to walk, and turn in response to an electrical stimulus to its nervous system with high repeatability of 60%. PMID:25740855

  11. Locomotion control of hybrid cockroach robots.

    PubMed

    Sanchez, Carlos J; Chiu, Chen-Wei; Zhou, Yan; González, Jorge M; Vinson, S Bradleigh; Liang, Hong

    2015-04-06

    Natural systems retain significant advantages over engineered systems in many aspects, including size and versatility. In this research, we develop a hybrid robotic system using American (Periplaneta americana) and discoid (Blaberus discoidalis) cockroaches that uses the natural locomotion and robustness of the insect. A tethered control system was firstly characterized using American cockroaches, wherein implanted electrodes were used to apply an electrical stimulus to the prothoracic ganglia. Using this approach, larger discoid cockroaches were engineered into a remotely controlled hybrid robotic system. Locomotion control was achieved through electrical stimulation of the prothoracic ganglia, via a remotely operated backpack system and implanted electrodes. The backpack consisted of a microcontroller with integrated transceiver protocol, and a rechargeable battery. The hybrid discoid roach was able to walk, and turn in response to an electrical stimulus to its nervous system with high repeatability of 60%.

  12. Injection nozzle materials for a coal-fueled diesel locomotive

    SciTech Connect

    Mehan, R.L.; Leonard, G.L.; Johnson, R.N.; Lavigne, R.G.

    1990-12-31

    In order to identify materials resistant to coal water mixture (CWM) erosive wear, a number of materials were evaluated using both orifice slurry and dry air erosion tests. Both erosion tests ranked materials in the same order, and the most erosion resistant material identified was sintered diamond compact. Based on operation using CWM in a single-cylinder locomotive test, superhard nozzle materials such as diamond, cubic boron nitride, and perhaps TiB{sub 2} were found to be necessary in order to obtain a reasonable operating life. An injection nozzle using sintered diamond compacts was designed and built, and has operated successfully in a CWM fired locomotive engine.

  13. Scaling macroscopic aquatic locomotion

    NASA Astrophysics Data System (ADS)

    Gazzola, Mattia; Argentina, Médéric; Mahadevan, L.

    2014-10-01

    Inertial aquatic swimmers that use undulatory gaits range in length L from a few millimetres to 30 metres, across a wide array of biological taxa. Using elementary hydrodynamic arguments, we uncover a unifying mechanistic principle characterizing their locomotion by deriving a scaling relation that links swimming speed U to body kinematics (tail beat amplitude A and frequency ω) and fluid properties (kinematic viscosity ν). This principle can be simply couched as the power law Re ~ Swα, where Re = UL/ν >> 1 and Sw = ωAL/ν, with α = 4/3 for laminar flows, and α = 1 for turbulent flows. Existing data from over 1,000 measurements on fish, amphibians, larvae, reptiles, mammals and birds, as well as direct numerical simulations are consistent with our scaling. We interpret our results as the consequence of the convergence of aquatic gaits to the performance limits imposed by hydrodynamics.

  14. Scaling macroscopic aquatic locomotion

    NASA Astrophysics Data System (ADS)

    Gazzola, Mattia; Argentina, Mederic; Mahadevan, Lakshminarayanan

    2014-11-01

    Inertial aquatic swimmers that use undulatory gaits range in length L from a few millimeters to 30 meters, across a wide array of biological taxa. Using elementary hydrodynamic arguments, we uncover a unifying mechanistic principle characterizing their locomotion by deriving a scaling relation that links swimming speed U to body kinematics (tail beat amplitude A and frequency ω) and fluid properties (kinematic viscosity ν). This principle can be simply couched as the power law Re ~ Swα , where Re = UL / ν >> 1 and Sw = ωAL / ν , with α = 4 / 3 for laminar flows, and α = 1 for turbulent flows. Existing data from over 1000 measurements on fish, amphibians, larvae, reptiles, mammals and birds, as well as direct numerical simulations are consistent with our scaling. We interpret our results as the consequence of the convergence of aquatic gaits to the performance limits imposed by hydrodynamics.

  15. Locomotion speeds of various dinosaurs

    NASA Astrophysics Data System (ADS)

    Dougherty, Mary; Lee, Scott

    2009-03-01

    Most students have a passing curiosity about dinosaurs. Piquing this interest is an excellent tool to engage students. A methodology for estimating the locomotion speed of an animal based upon their footprint tracks is developed. Using this technique, an analysis of the locomotion speeds of various dinosaurs is performed. The tracks studied include 28 theropods (meat-eating dinosaurs), 23 sauropods (the ``long-necked'' herbivores), 28 non-armored, non-sauropod herbivores and 10 armored, non-sauropod herbivores. The theropods show the fastest locomotion speed as well as the greatest variety of speeds while the armored dinosaurs are the slowest.

  16. Locomotion Speeds of Various Dinosaurs

    NASA Astrophysics Data System (ADS)

    Dougherty, M. T.; Lee, S. A.

    2009-04-01

    A methodology for estimating the locomotion speed of an animal based upon their footprint tracks is developed. Using this technique, an analysis of the locomotion speeds of various dinosaurs is performed. The tracks studied include 28 theropods (meat-eating dinosaurs), 23 sauropods (the ``long-necked'' herbivores), 28 non-armored, non-sauropod herbivores and 10 armored, non-sauropod herbivores. The theropods show the fastest locomotion speed as well as the greatest variety of speeds while the armored dinosaurs are the slowest.

  17. Self-improving biped locomotion

    NASA Astrophysics Data System (ADS)

    Teixeira, C.; Costa, L.; Santos, C.

    2013-10-01

    An approach addressing biped locomotion is here introduced. Central Pattern Generators (CPGs) and Dynamic Movement Primitives (DMPs) were combined to easily produce complex trajectories for the joints of a simulated DARwIn-OP. Policy Learning by Weighting Exploration with the Returns (PoWER) was implemented to improve the robot's locomotion through variation of the DMP's parameters. Maximization of the DARwIn-OP's frontal velocity was addressed and results show a velocity improvement of 213%. The results are very promising and demonstrate the approach's flexibility at generating new trajectories for locomotion.

  18. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... cab cars and MU locomotives. 238.209 Section 238.209 Transportation Other Regulations Relating to... locomotives, including cab cars and MU locomotives. (a)(1) The skin covering the forward-facing end of each locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate...

  19. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cab cars and MU locomotives. 238.209 Section 238.209 Transportation Other Regulations Relating to... locomotives, including cab cars and MU locomotives. (a)(1) The skin covering the forward-facing end of each locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate...

  20. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... cab cars and MU locomotives. 238.209 Section 238.209 Transportation Other Regulations Relating to... locomotives, including cab cars and MU locomotives. (a)(1) The skin covering the forward-facing end of each locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate...

  1. Advanced underground Vehicle Power and Control: The locomotive Research Platform

    SciTech Connect

    Vehicle Projects LLC

    2003-01-28

    Develop a fuelcell mine locomotive with metal-hydride hydrogen storage. Test the locomotive for fundamental limitations preventing successful commercialization of hydride fuelcells in underground mining. During Phase 1 of the DOE-EERE sponsored project, FPI and its partner SNL, completed work on the development of a 14.4 kW fuelcell power plant and metal-hydride energy storage. An existing battery-electric locomotive with similar power requirements, minus the battery module, was used as the base vehicle. In March 2001, Atlas Copco Wagner of Portland, OR, installed the fuelcell power plant into the base vehicle and initiated integration of the system into the vehicle. The entire vehicle returned to Sandia in May 2001 for further development and integration. Initial system power-up took place in December 2001. A revision to the original contract, Phase 2, at the request of DOE Golden Field Office, established Vehicle Projects LLC as the new prime contractor,. Phase 2 allowed industry partners to conduct surface tests, incorporate enhancements to the original design by SNL, perform an extensive risk and safety analysis, and test the fuelcell locomotive underground under representative production mine conditions. During the surface tests one of the fuelcell stacks exhibited reduced power output resulting in having to replace both fuelcell stacks. The new stacks were manufactured with new and improved technology resulting in an increase of the gross power output from 14.4 kW to 17 kW. Further work by CANMET and Hatch Associates, an engineering consulting firm specializing in safety analysis for the mining industry, both under subcontract to Vehicle Projects LLC, established minimum requirements for underground testing. CANMET upgraded the Programmable Logic Control (PLC) software used to monitor and control the fuelcell power plant, taking into account locomotive operator's needs. Battery Electric, a South Africa manufacturer, designed and manufactured (at no cost to

  2. Coal-fueled diesel locomotive test

    SciTech Connect

    Hsu, B.D.; McDowell, R.E.; Confer, G.L.; Basic, S.L.

    1993-01-01

    The biggest challenges to the development of a commercially-acceptable coal-fueled diesel-electric locomotive are integrating all systems into a working unit that can be operated in railroad service. This involves mainly the following three systems: (1) the multi-cylinder coal-fueled diesel engine, (2) the locomotive and engine controls, and (3) the CWS fuel supply system. Consequently, a workable 12-cylinder coal-fueled diesel engine was considered necessary at this stage to evolve the required locomotive support systems, in addition to gaining valuable multi-cylinder engine operating experience. The CWS fuel used during this project was obtained from Otisca, Inc. (Syracuse, NY). It was prepared from micronized and deashed Kentucky Blue Gem coal to 49.0% coal loading by weight, with less than 1% ash and 5 micron mean diameter particle size. Its higher heating value was analyzed at approximately 34630 kJ/k. Anti-agglomerating additive Triton X-114 was added to the CWS at GE Transportation Systems at 2% of coal weight. The nature of the Otisca CWS fuel makes it inherently more difficult to store, pump, and inject than diesel fuel, since concepts which govern Newtonian or normally viscous liquids do not apply entirely to CWS. Otisca CWS tends to be unstable and to settle in tanks and lines after a period of time, making it necessary to provide a means of agitation during storage. To avoid long term settling problems and to minimize losses, piping velocities were designed to be in the 60-90 m/min range.

  3. 40 CFR 92.511 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... ENGINES Manufacturer and Remanufacturer Production Line Testing and Audit Programs § 92.511 Remanufactured locomotives: installation audit requirements. (a) Remanufacturers of locomotives or locomotive engines shall..., component settings and component installations on randomly chosen locomotives in an engine family....

  4. 40 CFR 92.511 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... locomotives: installation audit requirements. (a) Remanufacturers of locomotives or locomotive engines shall...: installation audit requirements. 92.511 Section 92.511 Protection of Environment ENVIRONMENTAL PROTECTION..., component settings and component installations on randomly chosen locomotives in an engine family....

  5. Decoding the organization of spinal circuits that control locomotion

    PubMed Central

    Kiehn, Ole

    2016-01-01

    Unravelling the functional operation of neuronal networks and linking cellular activity to specific behavioural outcomes are among the biggest challenges in neuroscience. In this broad field of research, substantial progress has been made in studies of the spinal networks that control locomotion. Through united efforts using electrophysiological and molecular genetic network approaches and behavioural studies in phylogenetically diverse experimental models, the organization of locomotor networks has begun to be decoded. The emergent themes from this research are that the locomotor networks have a modular organization with distinct transmitter and molecular codes and that their organization is reconfigured with changes to the speed of locomotion or changes in gait. PMID:26935168

  6. Current problems: New similiquid lubricant for locomotive gears

    SciTech Connect

    Shibryaev, S.B.; Nesterov, A.V.; Seregina, I.E.

    1995-01-01

    The development of a formula for a new, domestically manufactured, semiliquid lubricant is described. The lubricant is for traction gears of locomotives and motorized cars of multiple-unit trains that will ensure year-round operation. Scientific principles have been used in selecting additives and in increasing the effectiveness of the additives by means of oxygen-containing synthetic oils.

  7. System design of a large fuel cell hybrid locomotive

    NASA Astrophysics Data System (ADS)

    Miller, A. R.; Hess, K. S.; Barnes, D. L.; Erickson, T. L.

    Fuel cell power for locomotives combines the environmental benefits of a catenary-electric locomotive with the higher overall energy efficiency and lower infrastructure costs of a diesel-electric. A North American consortium, a public-private partnership, is developing a prototype hydrogen-fueled fuel cell-battery hybrid switcher locomotive for urban and military-base rail applications. Switcher locomotives are used in rail yards for assembling and disassembling trains and moving trains from one point to another. At 127 tonnes (280,000 lb), continuous power of 250 kW from its (proton exchange membrane) PEM fuel cell prime mover, and transient power well in excess of 1 MW, the hybrid locomotive will be the heaviest and most powerful fuel cell land vehicle yet. This fast-paced project calls for completion of the vehicle itself near the end of 2007. Several technical challenges not found in the development of smaller vehicles arise when designing and developing such a large fuel cell vehicle. Weight, center of gravity, packaging, and safety were design factors leading to, among other features, the roof location of the lightweight 350 bar compressed hydrogen storage system. Harsh operating conditions, especially shock loads during coupling to railcars, require component mounting systems capable of absorbing high energy. Vehicle scale-up by increasing mass, density, or power presents new challenges primarily related to issues of system layout, hydrogen storage, heat transfer, and shock loads.

  8. Locomotion: Control from the Periphery?

    PubMed

    Wyart, Claire

    2017-02-20

    Studies of the neural control of locomotion have tended to focus on the modulation of motoneuron firing by premotor neurons; new work indicates that the regulation of synaptic transmission at the neuromuscular junction can also be important, revealing an inverse relationship between input resistance and synaptic output in motoneurons.

  9. 21st Century Locomotive Technology: 2003 Annual Technical Status Report DOE/AL68284-TSR03

    SciTech Connect

    Lembit Salasoo

    2004-01-09

    The 21st Century Locomotive program objective is to develop 25% more efficient freight locomotives by 2010. Diesel engine-related research addresses advanced fuel injection, electric turbocharger and abradable seals. Assembly of a common rail fuel injection test system is underway, and a CFD combustion model has been validated. An electrically assisted turbocharger has been constructed and operated, meeting the generator mode design rating. System characterization and optimization is ongoing. Candidate abradable seal materials have been identified and test coupons prepared. Locomotive system-related research addresses capturing, storing and utilizing regenerative braking energy in a hybrid locomotive, and fuel optimization control. Hybrid locomotive energy storage requirements have been identified and studies on specific energy storage solutions are in progress. Energy management controls have been defined and testing initiated. Train and track parameter identification necessary for fuel optimization has been demonstrated.

  10. Proprioceptive Actuation Design for Dynamic Legged locomotion

    NASA Astrophysics Data System (ADS)

    Kim, Sangbae; Wensing, Patrick; Biomimetic Robotics Lab Team

    Designing an actuator system for highly-dynamic legged locomotion exhibited by animals has been one of the grand challenges in robotics research. Conventional actuators designed for manufacturing applications have difficulty satisfying challenging requirements for high-speed locomotion, such as the need for high torque density and the ability to manage dynamic physical interactions. It is critical to introduce a new actuator design paradigm and provide guidelines for its incorporation in future mobile robots for research and industry. To this end, we suggest a paradigm called proprioceptive actuation, which enables highly- dynamic operation in legged machines. Proprioceptive actuation uses collocated force control at the joints to effectively control contact interactions at the feet under dynamic conditions. In the realm of legged machines, this paradigm provides a unique combination of high torque density, high-bandwidth force control, and the ability to mitigate impacts through backdrivability. Results show that the proposed design provides an impact mitigation factor that is comparable to other quadruped designs with series springs to handle impact. The paradigm is shown to enable the MIT Cheetah to manage the application of contact forces during dynamic bounding, with results given down to contact times of 85ms and peak forces over 450N. As a result, the MIT Cheetah achieves high-speed 3D running up to 13mph and jumping over an 18-inch high obstacle. The project is sponsored by DARPA M3 program.

  11. Fuel consumption of freight trains hauled by diesel electric locomotives

    SciTech Connect

    Radford, R.W.

    1983-05-01

    The cost of railway diesel fuel has become an increasingly high proportion of railway operating expenses. The paper analyzes the generation and utilization of rail horsepower in freight train operations. The effects on fuel consumption of variations in several parameters including train consist, car weight, gradient, average speed, meet strategy, throttle control, locomotive axle arrangement, and train marshalling are examined. Estimates are made of the value, in terms of fuel cost, of weight reduction of freight cars and of selective train marshalling.

  12. Locomotive assignment problem with train precedence using genetic algorithm

    NASA Astrophysics Data System (ADS)

    Noori, Siamak; Ghannadpour, Seyed Farid

    2012-07-01

    This paper aims to study the locomotive assignment problem which is very important for railway companies, in view of high cost of operating locomotives. This problem is to determine the minimum cost assignment of homogeneous locomotives located in some central depots to a set of pre-scheduled trains in order to provide sufficient power to pull the trains from their origins to their destinations. These trains have different degrees of priority for servicing, and the high class of trains should be serviced earlier than others. This problem is modeled using vehicle routing and scheduling problem where trains representing the customers are supposed to be serviced in pre-specified hard/soft fuzzy time windows. A two-phase approach is used which, in the first phase, the multi-depot locomotive assignment is converted to a set of single depot problems, and after that, each single depot problem is solved heuristically by a hybrid genetic algorithm. In the genetic algorithm, various heuristics and efficient operators are used in the evolutionary search. The suggested algorithm is applied to solve the medium sized numerical example to check capabilities of the model and algorithm. Moreover, some of the results are compared with those solutions produced by branch-and-bound technique to determine validity and quality of the model. Results show that suggested approach is rather effective in respect of quality and time.

  13. Locomotive Emission and Engine Idle Reduction Technology Demonstration Project

    SciTech Connect

    John R. Archer

    2005-03-14

    In response to a United States Department of Energy (DOE) solicitation, the Maryland Energy Administration (MEA), in partnership with CSX Transportation, Inc. (CSXT), submitted a proposal to DOE to support the demonstration of Auxiliary Power Unit (APU) technology on fifty-six CSXT locomotives. The project purpose was to demonstrate the idle fuel savings, the Nitrous Oxide (NOX) emissions reduction and the noise reduction capabilities of the APU. Fifty-six CSXT Baltimore Division locomotives were equipped with APUs, Engine Run Managers (ERM) and communications equipment to permit GPS tracking and data collection from the locomotives. Throughout the report there is mention of the percent time spent in the State of Maryland. The fifty-six locomotives spent most of their time inside the borders of Maryland and some spent all their time inside the state borders. Usually when a locomotive traveled beyond the Maryland State border it was into an adjoining state. They were divided into four groups according to assignment: (1) Power Unit/Switcher Mate units, (2) Remote Control units, (3) SD50 Pusher units and (4) Other units. The primary data of interest were idle data plus the status of the locomotive--stationary or moving. Also collected were main engine off, idling or working. Idle data were collected by county location, by locomotive status (stationary or moving) and type of idle (Idle 1, main engine idling, APU off; Idle 2, main engine off, APU on; Idle 3, main engine off, APU off; Idle 4, main engine idle, APU on). Desirable main engine idle states are main engine off and APU off or main engine off and APU on. Measuring the time the main engine spends in these desirable states versus the total time it could spend in an engine idling state allows the calculation of Percent Idle Management Effectiveness (%IME). IME is the result of the operation of the APU plus the implementation of CSXT's Warm Weather Shutdown Policy. It is difficult to separate the two. The units

  14. [Locomotive syndrome and frailty. Locomotive syndrome due to the underlying disease of degenerative arthritis].

    PubMed

    Chosa, Etsuo

    2012-04-01

    Japan became a superaging society. We have been putting a new focus on locomotive syndrome and frailty. The prevention and treatment of locomotive syndromes, such as osteoarthritis, degenerative spondylosis, lumbar canal stenosis, osteoporosis, upper extremity diseases, rheumatoid arthritis, and many other disorders of the locomotive organs are important. Because, the locomotive syndrome results in deterioration of the exercise function and loss of mental and physical health. The aim of locomotive syndrome exercises are: to reduce pain, to restore and improve joint function. We need to take a comprehensive approach to locomotive syndrome, including lifestyle modification, muscle exercise, stretching and therapeutic exercise.

  15. User Control of Simulated Locomotion

    DTIC Science & Technology

    2001-01-05

    position at the head to generate the virtual reference position in the virtual environment. Head sensor 34 .enables the viewpoint to move...place paces are easily mapped into stride length and cadences of the paces taken by the virtual reference or body. The system can also be tuned to...elements, the apparatus for interfacing locomotive 3D movements of a user 10 to a reference (or reference-point, point-of correspondence, virtual

  16. Emotion through Locomotion: Gender Impact

    PubMed Central

    Krüger, Samuel; Sokolov, Alexander N.; Enck, Paul; Krägeloh-Mann, Ingeborg; Pavlova, Marina A.

    2013-01-01

    Body language reading is of significance for daily life social cognition and successful social interaction, and constitutes a core component of social competence. Yet it is unclear whether our ability for body language reading is gender specific. In the present work, female and male observers had to visually recognize emotions through point-light human locomotion performed by female and male actors with different emotional expressions. For subtle emotional expressions only, males surpass females in recognition accuracy and readiness to respond to happy walking portrayed by female actors, whereas females exhibit a tendency to be better in recognition of hostile angry locomotion expressed by male actors. In contrast to widespread beliefs about female superiority in social cognition, the findings suggest that gender effects in recognition of emotions from human locomotion are modulated by emotional content of actions and opposite actor gender. In a nutshell, the study makes a further step in elucidation of gender impact on body language reading and on neurodevelopmental and psychiatric deficits in visual social cognition. PMID:24278456

  17. Lizard locomotion on weak sand

    NASA Astrophysics Data System (ADS)

    Goldman, Daniel

    2005-03-01

    Terrestrial animal locomotion in the natural world can involve complex foot-ground interaction; for example, running on sand probes the solid and fluid behaviors of the medium. We study locomotion of desert-dwelling lizard Callisaurus draconoides (length 16 cm, mass=20 g) during rapid running on sand. To explore the role of foot-ground interaction on locomotion, we study the impact of flat disks ( 2 cm diameter, 10 grams) into a deep (800 particle diameters) bed of 250 μm glass spheres of fixed volume fraction φ 0.59, and use a vertical flow of air (a fluidized bed) to change the material properties of the medium. A constant flow Q below the onset of bed fluidization weakens the solid: at fixed φ the penetration depth and time of a disk increases with increasing Q. We measure the average speed, foot impact depth, and foot contact time as a function of material strength. The animal maintains constant penetration time (30 msec) and high speed (1.4 m/sec) even when foot penetration depth varies as we manipulate material strength. The animals compensate for decreasing propulsion by increasing stride frequency.

  18. Stability of underwater periodic locomotion

    NASA Astrophysics Data System (ADS)

    Jing, Fangxu; Kanso, Eva

    2013-07-01

    Most aquatic vertebrates swim by lateral flapping of their bodies and caudal fins. While much effort has been devoted to understanding the flapping kinematics and its influence on the swimming efficiency, little is known about the stability (or lack of) of periodic swimming. It is believed that stability limits maneuverability and body designs/flapping motions that are adapted for stable swimming are not suitable for high maneuverability and vice versa. In this paper, we consider a simplified model of a planar elliptic body undergoing prescribed periodic heaving and pitching in potential flow. We show that periodic locomotion can be achieved due to the resulting hydrodynamic forces, and its value depends on several parameters including the aspect ratio of the body, the amplitudes and phases of the prescribed flapping.We obtain closedform solutions for the locomotion and efficiency for small flapping amplitudes, and numerical results for finite flapping amplitudes. This efficiency analysis results in optimal parameter values that are in agreement with values reported for some carangiform fish. We then study the stability of the (finite amplitude flapping) periodic locomotion using Floquet theory. We find that stability depends nonlinearly on all parameters. Interesting trends of switching between stable and unstable motions emerge and evolve as we continuously vary the parameter values. This suggests that, for live organisms that control their flapping motion, maneuverability and stability need not be thought of as disjoint properties, rather the organism may manipulate its motion in favor of one or the other depending on the task at hand.

  19. Lunar Balance and Locomotion

    NASA Technical Reports Server (NTRS)

    Paloski, William H.

    2008-01-01

    Balance control and locomotor patterns were altered in Apollo crewmembers on the lunar surface, owing, presumably, to a combination of sensory-motor adaptation during transit and lunar surface operations, decreased environmental affordances associated with the reduced gravity, and restricted joint mobility as well as altered center-of-gravity caused by the EVA pressure suits. Dr. Paloski will discuss these factors, as well as the potential human and mission impacts of falls and malcoordination during planned lunar sortie and outpost missions. Learning objectives: What are the potential impacts of postural instabilities on the lunar surface? CME question: What factors affect balance control and gait stability on the moon? Answer: Sensory-motor adaptation to the lunar environment, reduced mechanical and visual affordances, and altered biomechanics caused by the EVA suit.

  20. Kinematic Differences Between Motorized and Nonmotorized Treadmill Locomotion

    NASA Technical Reports Server (NTRS)

    DeWitt, John K.; Bentley, Jason R.; Lee, Stuart M. C.; Norcross, Jason; Smith, Cassie; Hagan, R. Donald

    2006-01-01

    There are few scientific publications comparing human locomotion between motorized and nonmotorized treadmills. Lakomy (1987) and Gamble et al (1988) reported that forward lean is greater on a nonmotorized treadmill to aid in the generation of horizontal force necessary for belt propulsion, but there are no data concerning lower limb kinematics. During long-term spaceflight, astronauts use locomotive exercise to mitigate the physiological effects caused by long-term exposure to microgravity. A critical decision for mission planners concerns the requirements for a treadmill to be used during potential trips to the Moon and Mars. Treadmill operation in an un-powered configuration could reduce mission resource demands, but also may impact the efficacy of treadmill exercise countermeasures. To ascertain the most appropriate type of treadmill to be used, it is important to understand biomechanical differences between motorized (M) and nonmotorized (NM) locomotion. The purpose of this evaluation was to test for differences in lower limb kinematics that occur during M and NM treadmill locomotion at two speeds. It was hypothesized that hip and knee joint angle trajectories would differ between the conditions.

  1. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the system... charge of a locomotive or locomotive consist, an engineer must know that the brakes are in...

  2. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the system... charge of a locomotive or locomotive consist, an engineer must know that the brakes are in...

  3. [Locomotive syndrome and metabolic syndrome].

    PubMed

    Fukushi, Jun-ichi; Iwamoto, Yukihide

    2014-10-01

    The Japanese Orthopedic Association coined the term locomotive syndrome (LS) to designate a condition of elderly people in high risk groups of requiring nursing care because of problems with their musculoskeletal diseases. LS is a socioeconomic concept, and closely associated with osteoporosis, osteoarthritis, and sarcopenia. Recent studies have revealed that metabolic syndrome (MS), a clustering of cardiovascular risk factors, has been related with LS. For example, individuals with MS have a greater risk of osteoarthritis and sarcopenia. Secreted factors from adipose tissue and skeletal muscles, namely, adipokines and myokines, are involved in the association of LS and MS.

  4. Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

    NASA Astrophysics Data System (ADS)

    Tang, N. W.; Kirchstetter, T.; Martien, P. T.; Apte, J.

    2015-12-01

    Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate "head-end" power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

  5. Measurement of black carbon emissions from in-use diesel-electric passenger locomotives in California

    NASA Astrophysics Data System (ADS)

    Tang, Nicholas W.; Apte, Joshua S.; Martien, Philip T.; Kirchstetter, Thomas W.

    2015-08-01

    Black carbon (BC) emission factors were measured for a California commuter rail line fleet of diesel-electric passenger locomotives (Caltrain). The emission factors are based on BC and carbon dioxide (CO2) concentrations in the exhaust plumes of passing locomotives, which were measured from pedestrian overpasses using portable analyzers. Each of the 29 locomotives in the fleet was sampled on 4-20 separate occasions at different locations to characterize different driving modes. The average emission factor expressed as g BC emitted per kg diesel consumed was 0.87 ± 0.66 g kg-1 (±1 standard deviation, n = 362 samples). BC emission factors tended to be higher for accelerating locomotives traveling at higher speeds with engines in higher notch settings. Higher fuel-based BC emission factors (g kg-1) were measured for locomotives equipped with separate "head-end" power generators (SEP-HEPs), which power the passenger cars, while higher time-based emission factors (g h-1) were measured for locomotives without SEP-HEPs, whose engines are continuously operated at high speeds to provide both head-end and propulsion power. PM10 emission factors, estimated assuming a BC/PM10 emission ratio of 0.6 and a typical power output-to-fuel consumption ratio, were generally in line with the Environmental Protection Agency's locomotive exhaust emission standards. Per passenger mile, diesel-electric locomotives in this study emit only 20% of the CO2 emitted by typical gasoline-powered light-duty vehicles (i.e., cars). However, the reduction in carbon footprint (expressed in terms of CO2 equivalents) due to CO2 emissions avoidance from a passenger commuting by train rather than car is appreciably offset by the locomotive's higher BC emissions.

  6. Novel locomotion via biological inspiration

    NASA Astrophysics Data System (ADS)

    Quinn, Roger D.; Boxerbaum, Alexander; Palmer, Luther; Chiel, Hillel; Diller, Eric; Hunt, Alexander; Bachmann, Richard

    2011-05-01

    Animal behavioral, physiological and neurobiological studies are providing a wealth of inspirational data for robot design and control. Several very different biologically inspired mobile robots will be reviewed. A robot called DIGbot is being developed that moves independent of the direction of gravity using Distributed Inward Gripping (DIG) as a rapid and robust attachment mechanism observed in climbing animals. DIGbot is an 18 degree of freedom hexapod with onboard power and control systems. Passive compliance in its feet, which is inspired by the flexible tarsus of the cockroach, increases the robustness of the adhesion strategy and enables DIGbot to execute large steps and stationary turns while walking on mesh screens. A Whegs™ robot, inspired by insect locomotion principles, is being developed that can be rapidly reconfigured between tracks and wheel-legs and carry GeoSystems Zipper Mast. The mechanisms that cause it to passively change its gait on irregular terrain have been integrated into its hubs for a compact and modular design. The robot is designed to move smoothly on moderately rugged terrain using its tracks and run on irregular terrain and stairs using its wheel-legs. We are also developing soft bodied robots that use peristalsis, the same method of locomotion earthworms use. We present a technique of using a braided mesh exterior to produce fluid waves of motion along the body of the robot that increase the robot's speed relative to previous designs. The concept is highly scalable, for endoscopes to water, oil or gas line inspection.

  7. Continuum limbed robots for locomotion

    NASA Astrophysics Data System (ADS)

    Mutlu, Alper

    This thesis focuses on continuum robots based on pneumatic muscle technology. We introduce a novel approach to use these muscles as limbs of lightweight legged robots. The flexibility of the continuum legs of these robots offers the potential to perform some duties that are not possible with classical rigid-link robots. Potential applications are as space robots in low gravity, and as cave explorer robots. The thesis covers the fabrication process of continuum pneumatic muscles and limbs. It also provides some new experimental data on this technology. Afterwards, the designs of two different novel continuum robots - one tripod, one quadruped - are introduced. Experimental data from tests using the robots is provided. The experimental results are the first published example of locomotion with tripod and quadruped continuum legged robots. Finally, discussion of the results and how far this technology can go forward is presented.

  8. Unifying Rules for Aquatic Locomotion

    NASA Astrophysics Data System (ADS)

    Saadat, Mehdi; Domel, August; di Santo, Valentina; Lauder, George; Haj-Hariri, Hossein

    2016-11-01

    Strouhal number, St (=fA/U) , a scaling parameter that relates speed, U, to the tail-beat frequency, f, and tail-beat amplitude, A, has been used many times to describe animal locomotion. It has been observed that swimming animals cruise at 0.2 <=St <=0.4. Using simple dimensional and scaling analyses supported by new experimental evidence of a self-propelled fish-like swimmer, we show that when cruising at minimum hydrodynamic input power, St is predetermined, and is only a function of the shape, i.e. drag coefficient and area. The narrow range for St, 0.2-0.4, has been previously associated with optimal propulsive efficiency. However, St alone is insufficient for deciding optimal motion. We show that hydrodynamic input power (energy usage to propel over a unit distance) in fish locomotion is minimized at all cruising speeds when A* (= A/L), a scaling parameter that relates tail-beat amplitude, A, to the length of the swimmer, L, is constrained to a narrow range of 0.15-0.25. Our analysis proposes a constraint on A*, in addition to the previously found constraint on St, to fully describe the optimal swimming gait for fast swimmers. A survey of kinematics for dolphin, as well as new data for trout, show that the range of St and A* for fast swimmers indeed are constrained to 0.2-0.4 and 0.15-0.25, respectively. Our findings provide physical explanation as to why fast aquatic swimmers cruise with relatively constant tail-beat amplitude at approximately 20 percent of body length, while their swimming speed is linearly correlated with their tail-beat frequency.

  9. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Production locomotives and engines. 92... (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Certification Provisions § 92.214 Production locomotives and engines. Any manufacturer or remanufacturer obtaining...

  10. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Production locomotives and engines. 92... (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Certification Provisions § 92.214 Production locomotives and engines. Any manufacturer or remanufacturer obtaining...

  11. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Production locomotives and engines. 92... (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Certification Provisions § 92.214 Production locomotives and engines. Any manufacturer or remanufacturer obtaining...

  12. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Production locomotives and engines. 92... (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Certification Provisions § 92.214 Production locomotives and engines. Any manufacturer or remanufacturer obtaining...

  13. 49 CFR 229.121 - Locomotive cab noise.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Locomotive cab noise. 229.121 Section 229.121... § 229.121 Locomotive cab noise. (a) Performance standards for locomotives. (1) When tested for static noise in accordance with paragraph (a)(3) of this section, all locomotives of each design or model...

  14. 49 CFR 229.121 - Locomotive cab noise.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Locomotive cab noise. 229.121 Section 229.121... § 229.121 Locomotive cab noise. (a) Performance standards for locomotives. (1) When tested for static noise in accordance with paragraph (a)(3) of this section, all locomotives of each design or model...

  15. 49 CFR 229.121 - Locomotive cab noise.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive cab noise. 229.121 Section 229.121... § 229.121 Locomotive cab noise. (a) Performance standards for locomotives. (1) When tested for static noise in accordance with paragraph (a)(3) of this section, all locomotives of each design or model...

  16. 49 CFR 238.223 - Locomotive fuel tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Locomotive fuel tanks. 238.223 Section 238.223... Equipment § 238.223 Locomotive fuel tanks. Locomotive fuel tanks shall comply with either the following or....21: (a) External fuel tanks. External locomotive fuel tanks shall comply with the...

  17. 49 CFR 238.223 - Locomotive fuel tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Locomotive fuel tanks. 238.223 Section 238.223... Equipment § 238.223 Locomotive fuel tanks. Locomotive fuel tanks shall comply with either the following or....21: (a) External fuel tanks. External locomotive fuel tanks shall comply with the...

  18. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  19. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  20. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  1. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  2. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  3. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive frame. 230.106 Section 230.106..., DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance...

  4. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  5. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  6. 49 CFR 230.21 - Steam locomotive number change.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive number change. 230.21 Section 230... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is...

  7. 49 CFR 238.223 - Locomotive fuel tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive fuel tanks. 238.223 Section 238.223... Equipment § 238.223 Locomotive fuel tanks. Locomotive fuel tanks shall comply with either the following or....21: (a) External fuel tanks. External locomotive fuel tanks shall comply with the...

  8. The primate semicircular canal system and locomotion

    PubMed Central

    Spoor, Fred; Garland, Theodore; Krovitz, Gail; Ryan, Timothy M.; Silcox, Mary T.; Walker, Alan

    2007-01-01

    The semicircular canal system of vertebrates helps coordinate body movements, including stabilization of gaze during locomotion. Quantitative phylogenetically informed analysis of the radius of curvature of the three semicircular canals in 91 extant and recently extinct primate species and 119 other mammalian taxa provide support for the hypothesis that canal size varies in relation to the jerkiness of head motion during locomotion. Primate and other mammalian species studied here that are agile and have fast, jerky locomotion have significantly larger canals relative to body mass than those that move more cautiously. PMID:17576932

  9. Warning system against locomotive driving wheel flaccidity

    NASA Astrophysics Data System (ADS)

    Luo, Peng

    2014-09-01

    Causes of locomotive relaxation are discussed. Alarm system against locomotive driving wheel flaccidity is designed by means of techniques of infrared temperature measurement and Hall sensor measurement. The design scheme of the system, the principle of detecting locomotive driving wheel flaccidity with temperature and Hall sensor is introduced, threshold temperature of infrared alarm is determined. The circuit system is designed by microcontroller technology and the software is designed with the assembly language. The experiment of measuring the flaccid displacement with Hall sensor measurement is simulated. The results show that the system runs well with high reliability and low cost, which has a wide prospect of application and popularization.

  10. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... four years of experience in locomotive construction or maintenance. A bachelor's degree in mechanical engineering or a related technical specialization may be substituted for two of the four years of...

  11. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... four years of experience in locomotive construction or maintenance. A bachelor's degree in mechanical engineering or a related technical specialization may be substituted for two of the four years of...

  12. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... four years of experience in locomotive construction or maintenance. A bachelor's degree in mechanical engineering or a related technical specialization may be substituted for two of the four years of...

  13. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... four years of experience in locomotive construction or maintenance. A bachelor's degree in mechanical engineering or a related technical specialization may be substituted for two of the four years of...

  14. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... four years of experience in locomotive construction or maintenance. A bachelor's degree in mechanical engineering or a related technical specialization may be substituted for two of the four years of...

  15. 76 FR 8699 - Locomotive Safety Standards; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF TRANSPORTATION Federal Railroad Administration 49 CFR Parts 229 and 238 RIN 2130-AC16 Locomotive Safety Standards; Correction AGENCY: Federal Railroad Administration (FRA), DOT. ACTION: Proposed rule; correction....

  16. Multi-limbed locomotion systems for space construction and maintenance

    NASA Technical Reports Server (NTRS)

    Waldron, K. J.; Klein, C. A.

    1987-01-01

    A well developed technology of coordination of multi-limbed locomotory systems is now available. Results from a NASA sponsored study of several years ago are presented. This was a simulation study of a three-limbed locomotion/manipulation system. Each limb had six degrees of freedom and could be used either as a locomotory grasping hand-holds, or as a manipulator. The focus of the study was kinematic coordination algorithms. The presentation will also include very recent results from the Adaptive Suspension Vehicle Project. The Adaptive Suspension Vehicle (ASV) is a legged locomotion system designed for terrestrial use which is capable of operating in completely unstructured terrain in either a teleoperated or operator-on-board mode. Future development may include autonomous operation. The ASV features a very advanced coordination and control system which could readily be adapted to operation in space. An inertial package with a vertical gyro, and rate gyros and accelerometers on three orthogonal axes provides body position information at high bandwidth. This is compared to the operator's commands, injected via a joystick to provide a commanded force system on the vehicle's body. This system is, in turn, decomposed by a coordination algorithm into force commands to those legs which are in contact with the ground.

  17. Kinematic determinants of human locomotion.

    PubMed Central

    Borghese, N A; Bianchi, L; Lacquaniti, F

    1996-01-01

    1. The aim of this study was to find kinematic patterns that are invariant across the normal range of locomotion speeds. Subjects walked at different, freely chosen speeds ranging from 0.9 to 2.1 m s-1, while motion and ground reaction forces on the right side of the body were recorded in three-dimensional space. 2. The time course of the anatomical angles of flexion-extension at the hip and ankle was variable not only across subjects, but even from trial to trial in the same subject. By contrast, the time course of the changes in the angles of elevation of each limb segment (pelvis, thigh, shank and foot) relative to the vertical was stereotyped across subjects. 3. To compare the waveforms across speeds, data were scaled in time relative to gait cycle duration. The pattern of ground reaction forces was highly speed dependent. Several distinct families of curves could be recognized in the flexion-extension angles at the hip and ankle. Instead, the waveforms of global length and elevation of the limb, elevation angles of all limb segments and flexion-extension at the knee were invariant with speed. 4. When gait trajectories at all speeds are plotted in the position space defined by the elevation angles of the limb segments, they describe regular loops on a plane. The statistical characteristics of these angular covariations were quantified by means of principal component analysis. The first two principal components accounted together for > 99% of the total experimental variance, and were quantitatively comparable in all subjects. 5. This constraint of planar covariation of the elevation angles is closely reminiscent of that previously described for the control of posture. The existence of laws of intersegmental co-ordination, common to the control of posture and locomotion, presumably assures the maintenance of dynamic equilibrium during forward progression, and the anticipatory adaptation to potentially destabilizing factors by means of co-ordinated kinematic

  18. Characterization of undulatory locomotion in granular media

    NASA Astrophysics Data System (ADS)

    Peng, Zhiwei; Pak, On Shun; Elfring, Gwynn

    2015-11-01

    Undulatory locomotion is ubiquitous in nature, from the swimming of flagellated microorganisms in biological fluids, to the slithering of snakes on land, or the locomotion of sandfish lizards in sand. Analysis of locomotion in granular materials is relatively less developed compared with fluids partially due to a lack of validated force models but a recently proposed resistive force theory (RFT) in granular media has been shown useful in studying the locomotion of a sand-swimming lizard. Here we employ this model to investigate the swimming characteristics of an undulating slender filament of both finite and infinite length. For infinite swimmers, similar to results in viscous fluids, the sawtooth waveform is found to be optimal for propulsion speed at a given power consumption. We also compare the swimming characteristics of sinusoidal and sawtooth swimmers with swimming in viscous fluids. More complex swimming dynamics emerge when the assumption of an infinite swimmer is removed. In particular, we characterize the effects of drifting and pitching in terms of propulsion speed and efficiency for a finite sinusoidal swimmer. The results complement our understanding of undulatory locomotion and provide insights into the effective design of locomotive systems in granular media.

  19. Characteristics of undulatory locomotion in granular media

    NASA Astrophysics Data System (ADS)

    Peng, Zhiwei; Pak, On Shun; Elfring, Gwynn J.

    2016-03-01

    Undulatory locomotion is ubiquitous in nature and observed in different media, from the swimming of flagellated microorganisms in biological fluids, to the slithering of snakes on land, or the locomotion of sandfish lizards in sand. Despite the similarity in the undulating pattern, the swimming characteristics depend on the rheological properties of different media. Analysis of locomotion in granular materials is relatively less developed compared with fluids partially due to a lack of validated force models but recently a resistive force theory in granular media has been proposed and shown useful in studying the locomotion of a sand-swimming lizard. Here we employ the proposed model to investigate the swimming characteristics of a slender filament, of both finite and infinite length, undulating in a granular medium and compare the results with swimming in viscous fluids. In particular, we characterize the effects of drifting and pitching in terms of propulsion speed and efficiency for a finite sinusoidal swimmer. We also find that, similar to Lighthill's results using resistive force theory in viscous fluids, the sawtooth swimmer is the optimal waveform for propulsion speed at a given power consumption in granular media. The results complement our understanding of undulatory locomotion and provide insights into the effective design of locomotive systems in granular media.

  20. Push-Pull Locomotion for Vehicle Extrication

    NASA Technical Reports Server (NTRS)

    Creager, Colin M.; Johnson, Kyle A.; Plant, Mark; Moreland, Scott J.; Skonieczny, Krzysztof

    2014-01-01

    For applications in which unmanned vehicles must traverse unfamiliar terrain, there often exists the risk of vehicle entrapment. Typically, this risk can be reduced by using feedback from on-board sensors that assess the terrain. This work addressed the situations where a vehicle has already become immobilized or the desired route cannot be traversed using conventional rolling. Specifically, the focus was on using push-pull locomotion in high sinkage granular material. Push-pull locomotion is an alternative mode of travel that generates thrust through articulated motion, using vehicle components as anchors to push or pull against. It has been revealed through previous research that push-pull locomotion has the capacity for generating higher net traction forces than rolling, and a unique optical flow technique indicated that this is the result of a more efficient soil shearing method. It has now been found that pushpull locomotion results in less sinkage, lower travel reduction, and better power efficiency in high sinkage material as compared to rolling. Even when starting from an "entrapped" condition, push-pull locomotion was able to extricate the test vehicle. It is the authors' recommendation that push-pull locomotion be considered as a reliable back-up mode of travel for applications where terrain entrapment is a possibility.

  1. Gravitational Effects upon Locomotion Posture

    NASA Technical Reports Server (NTRS)

    DeWitt, John K.; Bentley, Jason R.; Edwards, W. Brent; Perusek, Gail P.; Samorezov, Sergey

    2008-01-01

    Researchers use actual microgravity (AM) during parabolic flight and simulated microgravity (SM) obtained with horizontal suspension analogs to better understand the effect of gravity upon gait. In both environments, the gravitational force is replaced by an external load (EL) that returns the subject to the treadmill. However, when compared to normal gravity (N), researchers consistently find reduced ground reaction forces (GRF) and subtle kinematic differences (Schaffner et al., 2005). On the International Space Station, the EL is applied by elastic bungees attached to a waist and shoulder harness. While bungees can provide EL approaching body weight (BW), their force-length characteristics coupled with vertical oscillations of the body during gait result in a variable load. However, during locomotion in N, the EL is consistently equal to 100% body weight. Comparisons between AM and N have shown that during running, GRF are decreased in AM (Schaffner et al, 2005). Kinematic evaluations in the past have focussed on joint range of motion rather than joint posture at specific instances of the gait cycle. The reduced GRF in microgravity may be a result of differing hip, knee, and ankle positions during contact. The purpose of this investigation was to compare joint angles of the lower extremities during walking and running in AM, SM, and N. We hypothesized that in AM and SM, joints would be more flexed at heel strike (HS), mid-stance (MS) and toe-off (TO) than in N.

  2. Patterned control of human locomotion

    PubMed Central

    Lacquaniti, Francesco; Ivanenko, Yuri P; Zago, Myrka

    2012-01-01

    There is much experimental evidence for the existence of biomechanical constraints which simplify the problem of control of multi-segment movements. In addition, it has been hypothesized that movements are controlled using a small set of basic temporal components or activation patterns, shared by several different muscles and reflecting global kinematic and kinetic goals. Here we review recent studies on human locomotion showing that muscle activity is accounted for by a combination of few basic patterns, each one timed at a different phase of the gait cycle. Similar patterns are involved in walking and running at different speeds, walking forwards or backwards, and walking under different loading conditions. The corresponding weights of distribution to different muscles may change as a function of the condition, allowing highly flexible control. Biomechanical correlates of each activation pattern have been described, leading to the hypothesis that the co-ordination of limb and body segments arises from the coupling of neural oscillators between each other and with limb mechanical oscillators. Muscle activations need only intervene during limited time epochs to force intrinsic oscillations of the system when energy is lost. PMID:22411012

  3. Passive locomotion in unsteady flows

    NASA Astrophysics Data System (ADS)

    Ghaemi Oskouei, Babak; Kanso, Eva

    2010-11-01

    The passive locomotion of a submerged body in unsteady flow is studied. This work is motivated by recent experimental evidence that live and dead trout exploit vortices in the wake of an oscillating cylinder to swim upstream. We consider a simple model of a rigid body interacting dynamically with idealized wake models. The wake models consist of point vortices periodically introduced into the fluid domain to emulate shedding of vortices from an external un-modeled fixed or moving obstacle producing a "drag" or "thrust" wake, respectively. Both symmetric and staggered vortex configurations are considered. The submerged body is free to move in the plane, that is to say, it is not pinned at a given point. We do not prescribe a background flow, we rather consider the two-way coupled dynamics between the body's motion and the advection of ambient vortices. We show that both circular and elliptical bodies could "swim" passively against the flow by extracting energy from the ambient vortices. We obtain periodic trajectories for the body-vortex system and analyze their linear stability. We propose active feedback control strategies to overcome the instabilities.

  4. Bipedal locomotion in granular media

    NASA Astrophysics Data System (ADS)

    Kingsbury, Mark; Zhang, Tingnan; Goldman, Daniel

    Bipedal walking, locomotion characterized by alternating swing and double support phase, is well studied on ground where feet do not penetrate the substrate. On granular media like sand however, intrusion and extrusion phases also occur. In these phases, relative motion of the two feet requires that one or both feet slip through the material, degrading performance. To study walking in these phases, we designed and studied a planarized bipedal robot (1.6 kg, 42 cm) that walked in a fluidized bed of poppy seeds. We also simulated the robot in a multibody software environment (Chrono) using granular resistive force theory (RFT) to calculate foot forces. In experiment and simulation, the robot experienced slip during the intrusion phase, with the experiment presenting additional slip due to motor control error during the double support phase. This exaggerated slip gave insight (through analysis of ground reaction forces in simulation) into how slip occurs when relative motion exists between the two feet in the granular media, where the foot with higher relative drag forces (from its instantaneous orientation, rotation, relative direction of motion, and depth) remains stationary. With this relationship, we generated walking gaits for the robot to walk with minimal slip.

  5. Locomotion in a turbulent world

    NASA Astrophysics Data System (ADS)

    Koehl, M.

    2014-11-01

    When organisms swim or crawl in aquatic habitats, the water through which they travel is usually moving. Therefore, an important part of understanding how aquatic organisms locomote is determining how they interact with the fluctuating turbulent water currents through which they move. The research systems we have been using to address this question are microscopic marine animals swimming in turbulent, wavy water flow or crawling on surfaces in spatially-complex habitats exposed to such flow. Using a combination of field studies, wave-flume experiments, experiments in fluidic devices, and mathematical modeling, we have discovered that small organisms swimming or crawling in turbulent flow are not subjected to steady velocities. The shears, accelerations, and odor concentrations encountered by small swimmers and crawlers fluctuate rapidly, with peaks much higher than mean values. Although microscopic organisms swim slowly relative to ambient water flow, their locomotory behavior in response to the rapidly-fluctuating shears and odors they encounter can affect where they are transported by ambient water movement. Furthermore, the ability of small organisms to walk on surfaces without being dislodged by pulses of rapid flow constrains the microhabitats in which they can forage. Supported by NSF Grant #IOS-0842685.

  6. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... established to protect the public health or welfare from the dangers of air pollution.” (2) A statement that... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Recall...) A description of the adverse effects, if any, that an uncorrected nonconformity would have on...

  7. Limb and Trunk Mechanisms for Balance Control during Locomotion in Quadrupeds

    PubMed Central

    Musienko, Pavel E.; Deliagina, Tatiana G.; Gerasimenko, Yury P.; Orlovsky, Grigori N.

    2014-01-01

    In quadrupeds, the most critical aspect of postural control during locomotion is lateral stability. However, neural mechanisms underlying lateral stability are poorly understood. Here, we studied lateral stability in decerebrate cats walking on a treadmill with their hindlimbs. Two destabilizing factors were used: a brief lateral push of the cat and a sustained lateral tilt of the treadmill. It was found that the push caused considerable trunk bending and twisting, as well as changes in the stepping pattern, but did not lead to falling. Due to postural reactions, locomotion with normal body configuration was restored in a few steps. It was also found that the decerebrate cat could keep balance during locomotion on the laterally tilted treadmill. This postural adaptation was based on the transformation of the symmetrical locomotor pattern into an asymmetrical one, with different functional lengths of the right and left limbs. Then, we analyzed limb and trunk neural mechanisms contributing to postural control during locomotion. It was found that one of the limb mechanisms operates in the transfer phase and secures a standard (relative to the trunk) position for limb landing. Two other limb mechanisms operate in the stance phase; they counteract distortions of the locomotor pattern by regulating the limb stiffness. The trunk configuration mechanism controls the body shape on the basis of sensory information coming from trunk afferents. We suggest that postural reactions generated by these four mechanisms are integrated, thus forming a response of the whole system to perturbation of balance during locomotion. PMID:24741060

  8. Relationship between osteology and aquatic locomotion in birds: determining modes of locomotion in extinct Ornithurae.

    PubMed

    Hinić-Frlog, S; Motani, R

    2010-02-01

    The evolutionary history of aquatic invasion in birds would be incomplete without incorporation of extinct species. We show that aquatic affinities in fossil birds can be inferred by multivariate analysis of skeletal features and locomotion of 245 species of extant birds. Regularized discriminant analyses revealed that measurements of appendicular skeletons successfully separated diving birds from surface swimmers and flyers, while also discriminating among different underwater modes of swimming. The high accuracy of this method allows detection of skeletal characteristics that are indicative of aquatic locomotion and inference of such locomotion in bird species with insufficient behavioural information. Statistical predictions based on the analyses confirm qualitative assessments for both foot-propelled (Hesperornithiformes) and wing-propelled (Copepteryx) underwater locomotion in fossil birds. This is the first quantitative inference of underwater modes of swimming in fossil birds, enabling future studies of locomotion in extinct birds and evolutionary transitions among locomotor modes in avian lineage.

  9. Evolution of neural controllers for salamanderlike locomotion

    NASA Astrophysics Data System (ADS)

    Ijspeert, Auke J.

    1999-08-01

    This paper presents an experiment in which evolutionary algorithms are used for the development of neural controllers for salamander locomotion. The aim of the experiment is to investigate which kind of neural circuitry can produce the typical swimming and trotting gaits of the salamander, and to develop a synthetic approach to neurobiology by using genetic algorithms as design tool. A 2D bio-mechanical simulation of the salamander's body is developed whose muscle contraction is determined by the locomotion controller simulated as continuous-time neural networks. While the connectivity of the neural circuitry underlying locomotion in the salamander has not been decoded for the moment, the general organization of the designed neural circuits corresponds to that hypothesized by neurobiologist for the real animal. In particular, the locomotion controllers are based on a body central pattern generator (CPG) corresponding to a lamprey-like swimming controller as developed by Ekeberg, and are extended with a limb CPG for controlling the salamander's body. A genetic algorithm is used to instantiate synaptic weights of the connections within the limb CPG and from the limb CPG to the body CPG given a high level description of the desired gaits. A set of biologically plausible controllers are thus developed which can produce a neural activity and locomotion gaits very similar to those observed in the real salamander. By simply varying the external excitation applied to the network, the speed, direction and type of gait can be varied.

  10. Testosterone attenuates and the selective estrogen receptor modulator, raloxifene, potentiates amphetamine-induced locomotion in male rats.

    PubMed

    Purves-Tyson, Tertia D; Boerrigter, Danny; Allen, Katherine; Zavitsanou, Katerina; Karl, Tim; Djunaidi, Vanezha; Double, Kay L; Desai, Reena; Handelsman, David J; Weickert, Cynthia Shannon

    2015-04-01

    Although sex steroids are known to modulate brain dopamine, it is still unclear how testosterone modifies locomotor behaviour controlled, at least in part, by striatal dopamine in adolescent males. Our previous work suggests that increasing testosterone during adolescence may bias midbrain neurons to synthesise more dopamine. We hypothesised that baseline and amphetamine-induced locomotion would differ in adult males depending on testosterone exposure during adolescence. We hypothesised that concomitant stimulation of estrogen receptor signaling, through a selective estrogen receptor modulator (SERM), raloxifene, can counter testosterone effects on locomotion. Male Sprague-Dawley rats at postnatal day 45 were gonadectomised (G) or sham-operated (S) prior to the typical adolescent testosterone increase. Gonadectomised rats were either given testosterone replacement (T) or blank implants (B) for six weeks and sham-operated (i.e. intact or endogenous testosterone group) were given blank implants. Subgroups of sham-operated, gonadectomised and gonadectomised/testosterone-replaced rats were treated with raloxifene (R, 5mg/kg) or vehicle (V), daily for the final four weeks. There were six groups (SBV, GBV, GTV, SBR, GBR, GTR). Saline and amphetamine-induced (1.25mg/kg) locomotion in the open field was measured at PND85. Gonadectomy increased amphetamine-induced locomotion compared to rats with endogenous or with exogenous testosterone. Raloxifene increased amphetamine-induced locomotion in rats with either endogenous or exogenous testosterone. Amphetamine-induced locomotion was negatively correlated with testosterone and this relationship was abolished by raloxifene. Lack of testosterone during adolescence potentiates and testosterone exposure during adolescence attenuates amphetamine-induced locomotion. Treatment with raloxifene appears to potentiate amphetamine-induced locomotion and to have an opposite effect to that of testosterone in male rats.

  11. Neural organization of the locomotive oscillator.

    PubMed

    Willner, B E; Miranker, W L; Lu, C P

    1993-01-01

    We study the relation of neural development, organization, and activity to behavior. We provide a model of the locomotive oscillator, a neural system supplying alternating stimulation to extensor and flexor muscles creating an oscillatory motion. We propose a protocol by which this neural system starting from unstructured, unconnected neural populations develops structure and function. The protocol is studied by both computer simulation and mathematical analysis. Our main results are 1. The locomotive oscillator self-organizes and maintains its organization, assuming certain properties of the neural populations. 2. Imperfections disturbing the functional adequacy of the neural populations may lead to the deterioration and disappearance of the oscillatory behavior. 3. The locomotive oscillator may fail to organize if the development is not staged in time.

  12. Locomotion gaits of a rotating cylinder pair

    NASA Astrophysics Data System (ADS)

    van Rees, Wim M.; Novati, Guido; Koumoutsakos, Petros; Mahadevan, L.

    2015-11-01

    Using 2D numerical simulations of the Navier-Stokes equations, we demonstrate that a simple pair of rotating cylinders can display a range of locomotion patterns of biological and engineering interest. Steadily counter-rotating the cylinders causes the pair to move akin to a vortex dipole for low rotation rates, but as the rotational velocity is increased the direction of motion reverses. Unsteady rotations lead to different locomotion gaits that resemble jellyfish (for in-phase rotations) and undulating swimmers (for out-of-phase rotations). The small number of parameters for this simple system allows us to systematically map the phase space of these gaits, and allows us to understand the underlying physical mechanisms using a minimal model with implications for biological locomotion and engineered analogs.

  13. Comparison of kinematic and dynamic leg trajectory optimization techniques for biped robot locomotion

    NASA Astrophysics Data System (ADS)

    Khusainov, R.; Klimchik, A.; Magid, E.

    2017-01-01

    The paper presents comparison analysis of two approaches in defining leg trajectories for biped locomotion. The first one operates only with kinematic limitations of leg joints and finds the maximum possible locomotion speed for given limits. The second approach defines leg trajectories from the dynamic stability point of view and utilizes ZMP criteria. We show that two methods give different trajectories and demonstrate that trajectories based on pure dynamic optimization cannot be realized due to joint limits. Kinematic optimization provides unstable solution which can be balanced by upper body movement.

  14. Locomotion mode identification for lower limbs using neuromuscular and joint kinematic signals.

    PubMed

    Afzal, Taimoor; White, Gannon; Wright, Andrew B; Iqbal, Kamran

    2014-01-01

    Recent development in lower limb prosthetics has seen an emergence of powered prosthesis that have the capability to operate in different locomotion modes. However, these devices cannot transition seamlessly between modes such as level walking, stair ascent and descent and up slope and down slope walking. They require some form of user input that defines the human intent. The purpose of this study was to develop a locomotion mode detection system and evaluate its performance for different sensor configurations and to study the effect of locomotion mode detection with and without electromyography (EMG) signals while using kinematic data from hip joint of non-dominant/impaired limb and an accelerometer. Data was collected from four able bodied subjects that completed two circuits that contained standing, level-walking, ramp ascent and descent and stair ascent and descent. By using only the kinematic data from the hip joint and accelerometer data the system was able to identify the transitions, stance and swing phases with similar performance as compared to using only EMG and accelerometer data. However, significant improvement in classification error was observed when EMG, kinematic and accelerometer data were used together to identify the locomotion modes. The higher recognition rates when using the kinematic data along with EMG shows that the joint kinematics could be beneficial in intent recognition systems of locomotion modes.

  15. 7. Detail of the Grant Locomotive Works Erecting Shop looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. Detail of the Grant Locomotive Works Erecting Shop looking southwest showing ruined wall and entrance of a single story addition. - Grant Locomotive Works, Market & Spruce Streets, Paterson, Passaic County, NJ

  16. 19. AERIAL VIEW LOOKING WEST NORTHWEST SHOWING GRANT LOCOMOTIVE WORKS ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    19. AERIAL VIEW LOOKING WEST NORTHWEST SHOWING GRANT LOCOMOTIVE WORKS -- MACHINE SHOP, DANFORTH (COOKE) LOCOMOTIVE AND MACHINE CO., AND GODWIN (HAMIL) MILL. - Great Falls S. U. M. Historic District, Oliver Street, Paterson, Passaic County, NJ

  17. 40 CFR 92.1005 - In-use locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... railroad to schedule the supply of locomotives for testing in such a manner that it minimizes disruption of... schedule the supply of locomotives for testing in such a manner that it minimizes disruption of...

  18. 49 CFR 229.209 - Alternative locomotive crashworthiness designs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Alternative locomotive crashworthiness designs. 229.209 Section 229.209 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY...

  19. Locomotion of Paramecium in patterned environments

    NASA Astrophysics Data System (ADS)

    Park, Eun-Jik; Eddins, Aja; Kim, Junil; Yang, Sung; Jana, Saikat; Jung, Sunghwan

    2011-10-01

    Ciliary organisms like Paramecium Multimicronucleatum locomote by synchronized beating of cilia that produce metachronal waves over their body. In their natural environments they navigate through a variety of environments especially surfaces with different topology. We study the effects of wavy surfaces patterned on the PDMS channels on the locomotive abilities of Paramecium by characterizing different quantities like velocity amplitude and wavelength of the trajectories traced. We compare this result with the swimming characteristics in straight channels and draw conclusions about the effects of various patterned surfaces.

  20. Optimizing snake locomotion on an inclined plane.

    PubMed

    Wang, Xiaolin; Osborne, Matthew T; Alben, Silas

    2014-01-01

    We develop a model to study the locomotion of snakes on inclined planes. We determine numerically which snake motions are optimal for two retrograde traveling-wave body shapes, triangular and sinusoidal waves, across a wide range of frictional parameters and incline angles. In the regime of large transverse friction coefficients, we find power-law scalings for the optimal wave amplitudes and corresponding costs of locomotion. We give an asymptotic analysis to show that the optimal snake motions are traveling waves with amplitudes given by the same scaling laws found in the numerics.

  1. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  2. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  3. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  4. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  5. 49 CFR 230.101 - Steam locomotive driving journal boxes.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive driving journal boxes. 230.101... Locomotives and Tenders Running Gear § 230.101 Steam locomotive driving journal boxes. (a) Driving journal boxes. Driving journal boxes shall be maintained in a safe and suitable condition for service. Not...

  6. 40 CFR 92.104 - Locomotive and engine testing; overview.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... restriction within 1 inch of water of the upper limit of a typical engine as installed with clean air filters... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Locomotive and engine testing... PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures §...

  7. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Body structure, MU locomotives. 229.141 Section... Cab Equipment § 229.141 Body structure, MU locomotives. (a) MU locomotives built new after April 1... structure. (2) An anti-climbing arrangement shall be applied at each end that is designed so that coupled...

  8. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Body structure, MU locomotives. 229.141 Section... Cab Equipment § 229.141 Body structure, MU locomotives. (a) MU locomotives built new after April 1... structure. (2) An anti-climbing arrangement shall be applied at each end that is designed so that coupled...

  9. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Body structure, MU locomotives. 229.141 Section... Design Requirements § 229.141 Body structure, MU locomotives. (a) MU locomotives built new after April 1... structure. (2) An anti-climbing arrangement shall be applied at each end that is designed so that coupled...

  10. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Body structure, MU locomotives. 229.141 Section... Cab Equipment § 229.141 Body structure, MU locomotives. (a) MU locomotives built new after April 1... structure. (2) An anti-climbing arrangement shall be applied at each end that is designed so that coupled...

  11. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Body structure, MU locomotives. 229.141 Section... Design Requirements § 229.141 Body structure, MU locomotives. (a) MU locomotives built new after April 1... body structure designed to meet or exceed the following minimum specifications: (1) The body...

  12. 40 CFR 92.104 - Locomotive and engine testing; overview.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... restriction within 1 inch of water of the upper limit of a typical engine as installed with clean air filters... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Locomotive and engine testing; overview... PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures §...

  13. 40 CFR 92.104 - Locomotive and engine testing; overview.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... restriction within 1 inch of water of the upper limit of a typical engine as installed with clean air filters... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Locomotive and engine testing... PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures §...

  14. 40 CFR 1074.12 - Scope of preemption-specific provisions for locomotives and locomotive engines

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... period equivalent in length to 133 percent of the useful life, expressed as MW-hrs (or miles where applicable), beginning at the point at which the locomotive or engine becomes new, those standards or...

  15. 40 CFR 1074.12 - Scope of preemption-specific provisions for locomotives and locomotive engines

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... period equivalent in length to 133 percent of the useful life, expressed as MW-hrs (or miles where applicable), beginning at the point at which the locomotive or engine becomes new, those standards or...

  16. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  17. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  18. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  19. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  20. 49 CFR 210.9 - Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Movement of a noise defective locomotive, rail car, or consist of a locomotive and rail cars. 210.9 Section 210.9 Transportation Other Regulations... locomotive, rail car, or consist of a locomotive and rail cars. A locomotive, rail car, or consist of...

  1. Learning in the development of infant locomotion.

    PubMed

    Adolph, K E

    1997-01-01

    Infants master crawling and walking in an environment filled with varied and unfamiliar surfaces. At the same time, infants' bodies and skills continually change. The changing demands of everyday locomotion require infants to adapt locomotion to the properties of the terrain and to their own physical abilities. This Monograph examines how infants acquire adaptive locomotion in a novel task--going up and down slopes. Infants were tested longitudinally from their first week of crawling until several weeks after they began walking. Everyday locomotor experience played a central role in adaptive responding. Over weeks of crawling, infants' judgments became increasingly accurate, and exploration became increasingly efficient. There was no transfer over the transition from crawling to walking. Instead, infants learned, all over again, how to cope with slopes from an upright position. Findings indicate that learning generalized from everyday experience traveling over flat surfaces at home but that learning was specific to infants' typical method of locomotion and vantage point. Moreover, learning was not the result of simple associations between a particular locomotor response and a particular slope. Rather, infants learned to gauge their abilities on-line as they encountered each hill at the start of the trial. Change in locomotor responses and exploratory movements revealed a process of differentiation and selection spurred by changes in infants' everyday experience, body dimensions, and locomotor proficiency on flat ground.

  2. Learning in the Development of Infant Locomotion.

    ERIC Educational Resources Information Center

    Adolph, Karen E.

    1997-01-01

    Examined how infants acquire adaptive locomotion in the novel task of going up and down slopes. Found that infants' judgments became increasingly accurate and exploration became increasingly efficient, with no transfer over the transition from crawling to walking. Infants learned to gauge their abilities on-line as they encountered each hill at…

  3. Passive mechanics in jellyfish-like locomotion

    NASA Astrophysics Data System (ADS)

    Wilson, Megan; Eldredge, Jeff

    2008-11-01

    The aim of this work is to identify possible benefits of passive flexibility in biologically-inspired locomotion. Substantial energy savings are likely achieved in natural locomotion by allowing a mix of actively controlled and passively responsive deformation. The jellyfish is a useful target of study, due to its relatively simple structure and the availability of recent kinematics and flow-field measurements. In this investigation, the jellyfish consists of a two-dimensional articulated system of rigid bodies linked by hinges. The kinematics -- expressed via the hinge angles -- are adapted from experimentally measured motion. The free swimming system is explored via high-fidelity numerical simulation with a viscous vortex particle method with coupled body dynamics. The computational tool allows the arbitrary designation of individual hinges as ``active'' or ``passive,'' to introduce a mix of flexibility into the system. In some cases, replacing an active hinge with a passive spring can enhance the mean swimming speed, thus reducing the power requirements of the system. Varying the stiffness and damping coefficients of the spring yield different locomotive results. The numerical solution is used to compute the finite-time Lyapunov exponents (FTLE) throughout the field. The FTLE fields reveal manifolds in the flow that act as transport barriers, uncovering otherwise unseen geometric characteristics of the flow field that add new insight into the locomotion mechanics.

  4. Dynamic stabilization of rapid hexapedal locomotion.

    PubMed

    Jindrich, Devin L; Full, Robert J

    2002-09-01

    To stabilize locomotion, animals must generate forces appropriate to overcome the effects of perturbations and to maintain a desired speed or direction of movement. We studied the stabilizing mechanism employed by rapidly running insects by using a novel apparatus to perturb running cockroaches (Blaberus discoidalis). The apparatus used chemical propellants to accelerate a small projectile, generating reaction force impulses of less than 10 ms duration. The apparatus was mounted onto the thorax of the insect, oriented to propel the projectile laterally and loaded with propellant sufficient to cause a nearly tenfold increase in lateral velocity relative to maxima observed during unperturbed locomotion. Cockroaches were able to recover from these perturbations in 27+/-12 ms (mean +/- S.D., N=9) when running on a high-friction substratum. Lateral velocity began to decrease 13+/-5 ms (mean +/- S.D., N=11) following the start of a perturbation, a time comparable with the fastest reflexes measured in cockroaches. Cockroaches did not require step transitions to recover from lateral perturbations. Instead, they exhibited viscoelastic behavior in the lateral direction, with spring constants similar to those observed during unperturbed locomotion. The rapid onset of recovery from lateral perturbations supports the possibility that, during fast locomotion, intrinsic properties of the musculoskeletal system augment neural stabilization by reflexes.

  5. 77 FR 23159 - Locomotive Safety Standards; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF TRANSPORTATION Federal Railroad Administration 49 CFR Parts 229 and 238 RIN 2130-AC16 Locomotive Safety Standards; Correction AGENCY: Federal Railroad Administration (FRA), DOT. ACTION: Final rule; correction. SUMMARY:...

  6. 30 CFR 57.6203 - Locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface.... When explosive material is hauled by trolley locomotive, covered, electrically insulated cars shall...

  7. 30 CFR 57.6203 - Locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-UNDERGROUND METAL AND NONMETAL MINES Explosives Transportation-Surface.... When explosive material is hauled by trolley locomotive, covered, electrically insulated cars shall...

  8. 30 CFR 56.6203 - Locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6203... trolley locomotive, covered, electrically insulated cars shall be used....

  9. 30 CFR 56.6203 - Locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND HEALTH SAFETY AND HEALTH STANDARDS-SURFACE METAL AND NONMETAL MINES Explosives Transportation § 56.6203... trolley locomotive, covered, electrically insulated cars shall be used....

  10. Muscle spindle and fusimotor activity in locomotion.

    PubMed

    Ellaway, Peter H; Taylor, Anthony; Durbaba, Rade

    2015-08-01

    Mammals may exhibit different forms of locomotion even within a species. A particular form of locomotion (e.g. walk, run, bound) appears to be selected by supraspinal commands, but the precise pattern, i.e. phasing of limbs and muscles, is generated within the spinal cord by so-called central pattern generators. Peripheral sense organs, particularly the muscle spindle, play a crucial role in modulating the central pattern generator output. In turn, the feedback from muscle spindles is itself modulated by static and dynamic fusimotor (gamma) neurons. The activity of muscle spindle afferents and fusimotor neurons during locomotion in the cat is reviewed here. There is evidence for some alpha-gamma co-activation during locomotion involving static gamma motoneurons. However, both static and dynamic gamma motoneurons show patterns of modulation that are distinct from alpha motoneuron activity. It has been proposed that static gamma activity may drive muscle spindle secondary endings to signal the intended movement to the central nervous system. Dynamic gamma motoneuron drive appears to prime muscle spindle primary endings to signal transitions in phase of the locomotor cycle. These findings come largely from reduced animal preparations (decerebrate) and require confirmation in freely moving intact animals.

  11. Locomotion of C elegans in structured environments

    NASA Astrophysics Data System (ADS)

    Majmudar, Trushant; Keaveny, Eric; Shelley, Michael; Zhang, Jun

    2010-11-01

    Undulatory locomotion of microorganisms like soil-dwelling worms and sperm, in structured environments, is ubiquitous in nature. They navigate complex environments consisting of fluids and obstacles, negotiating hydrodynamic effects and geometrical constraints. Here we report experimental observations on the locomotion of C elegans swimming in arrays of micro-pillars in square lattices, with different lattice spacing. We observe that the worm employs a number of different locomotion strategies depending on the lattice spacing. As observed previously in the literature, we uncover regimes of enhanced locomotion, where the velocity is much higher than the free-swimming velocity. In addition, we also observe changes in frequency, velocity, and the gait of the worm as a function of lattice spacing. We also track the worm over time and find that it exhibits super-diffusive behavior and covers a larger area by utilizing the obstacles. These results may have significant impact on the foraging behavior of the worm in its natural environment. Our experimental approach, in conjunction with modeling and simulations, allows us to disentangle the effects of structure and hydrodynamics for an undulating microorganism.

  12. Energetics and mechanics for partial gravity locomotion.

    PubMed

    Newman, D J; Alexander, H L; Webbon, B W

    1994-09-01

    The role of gravitational acceleration on human locomotion is not clearly understood. It is hypothesized that the mechanics and energetics of locomotion depend upon the prevailing gravity level. A unique human-rated underwater treadmill and an adjustable ballasting harness were used to stimulate partial gravity environments. This study has two research aspects, biomechanics and energetics. Vertical forces which are exerted by subjects on the treadmill-mounted, split-plate force platform show that peak vertical force and stride frequency significantly decrease (p < 0.05) as the gravity level is reduced, while ground contact time is independent of gravity level. A loping gait is employed over a wide range of speeds (approximately 1.5 m/s to approximately 2.3 m/s) suggesting a change in the mechanics for lunar (1/6 G) and Martian (3/8 G) locomotion. As theory predicts, locomotion energy requirements for partial gravity levels are significantly less than at 1 G (p < 0.05).

  13. Evidence for Motor Simulation in Imagined Locomotion

    ERIC Educational Resources Information Center

    Kunz, Benjamin R.; Creem-Regehr, Sarah H.; Thompson, William B.

    2009-01-01

    A series of experiments examined the role of the motor system in imagined movement, finding a strong relationship between imagined walking performance and the biomechanical information available during actual walking. Experiments 1 through 4 established the finding that real and imagined locomotion differ in absolute walking time. We then tested…

  14. Interactions between locomotion and ventilation in tetrapods.

    PubMed

    Boggs, Dona F

    2002-10-01

    Interactions between locomotion and ventilation have now been studied in several species of reptiles, birds and mammals, from a variety of perspectives. Among these perspectives are neural interactions of separate but linked central controllers; mechanical impacts of locomotion upon ventilatory pressures and flows; and the extent to which the latter may affect gas exchange and the energetics of exercise. A synchrony, i.e. 1:1 pattern of coordination, is observed in many running mammals once they achieve galloping speeds, as well as in flying bats, some flying birds and hopping marsupials. Other, non-1:1, patterns of coordination are seen in trotting and walking quadrupeds, as well as running bipedal humans and running and flying birds. There is evidence for an energetic advantage to coordination of locomotor and respiratory cycles for flying birds and running mammals. There is evidence for a mechanical constraint upon ventilation by locomotion for some reptiles (e.g. iguana), but not for others (e.g. varanids and crocodilians). In diving birds the impact of wing flapping or foot paddling on differential air sac pressures enhances gas exchange during the breath hold by improving diffusive and convective movement of air sac oxygen to parabronchi. This paper will review the current state of our knowledge of such influences of locomotion upon respiratory system function.

  15. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... produces a minimum sound level of 96 dB(A) and a maximum sound level of 110 dB(A) at 100 feet forward of...), or (b)(3) of this section, shall not be required to undergo sound level testing when equipped with a... locomotive horn sound level shall be in accordance with the following requirements: (1) A properly...

  16. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... produces a minimum sound level of 96 dB(A) and a maximum sound level of 110 dB(A) at 100 feet forward of...), or (b)(3) of this section, shall not be required to undergo sound level testing when equipped with a... locomotive horn sound level shall be in accordance with the following requirements: (1) A properly...

  17. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... produces a minimum sound level of 96 dB(A) and a maximum sound level of 110 dB(A) at 100 feet forward of...), or (b)(3) of this section, shall not be required to undergo sound level testing when equipped with a... locomotive horn sound level shall be in accordance with the following requirements: (1) A properly...

  18. Lizard locomotion in heterogeneous granular media

    NASA Astrophysics Data System (ADS)

    Schiebel, Perrin; Goldman, Daniel

    2014-03-01

    Locomotion strategies in heterogeneous granular environments (common substrates in deserts), are relatively unexplored. The zebra-tailed lizard (C. draconoides) is a useful model organism for such studies owing to its exceptional ability to navigate a variety of desert habitats at impressive speed (up to 50 body-lengths per second) using both quadrapedal and bidepal gaits. In laboratory experiments, we challenge the lizards to run across a field of boulders (2.54 cm diameter glass spheres or 3.8 cm 3D printed spheres) placed in a lattice pattern and embedded in a loosely packed granular medium of 0.3 mm diameter glass particles. Locomotion kinematics of the lizard are recorded using high speed cameras, with and without the scatterers. The data reveals that unlike the lizard's typical quadrupedal locomotion using a diagonal gait, when scatterers are present the lizard is most successful when using a bipedal gait, with a raised center of mass (CoM). We propose that the kinematics of bipedal running in conjunction with the lizard's long toes and compliant hind foot are the keys to this lizard's successful locomotion in the presence of such obstacles. NSF PoLS

  19. Aerodynamic Design of a Locomotive Fairing

    NASA Astrophysics Data System (ADS)

    Stucki, Chad; Maynes, Daniel

    2016-11-01

    Rising fuel cost has motivated increased fuel efficiency of freight trains. At cruising speed, the largest contributing factor to the fuel consumption is the aerodynamic drag. As a result of air stagnation at the front of the train and substantial flow separation behind, the leading locomotive and trailing railcar experience greater drag than intermediate cars. This work introduces the design of streamlined nose fairings to be attached to freight locomotives as a means of reducing the leading locomotive drag. The aerodynamic performance of each fairing design is modeled using a commercial CFD software package. The K-epsilon turbulence model is used, and fluid properties are equivalent to atmospheric air at standard conditions. A selection of isolated screening studies are performed, and a multidimensional regression is used to predict optimal-performing fairing designs. Between screening studies, careful examination of the flow field is performed to inspire subsequent fairing designs. Results are presented for 250 different nose fairings. The best performing fairing geometry predicts a nominal drag reduction of 17% on the lead locomotive in a train set. This drag reduction is expected to result in nearly 1% fuel savings for the entire train.

  20. 49 CFR 1242.60 - Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives (accounts XX-51-67, XX-51-68 and XX-51-69). 1242.60 Section...-Transportation § 1242.60 Locomotive fuel, electric power purchased/produced for motive power and...

  1. 49 CFR 1242.60 - Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives (accounts XX-51-67, XX-51-68 and XX-51-69). 1242.60 Section...-Transportation § 1242.60 Locomotive fuel, electric power purchased/produced for motive power and...

  2. 49 CFR 1242.60 - Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 9 2013-10-01 2013-10-01 false Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives (accounts XX-51-67, XX-51-68 and XX-51-69). 1242.60 Section...-Transportation § 1242.60 Locomotive fuel, electric power purchased/produced for motive power and...

  3. 49 CFR 1242.60 - Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 9 2012-10-01 2012-10-01 false Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives (accounts XX-51-67, XX-51-68 and XX-51-69). 1242.60 Section...-Transportation § 1242.60 Locomotive fuel, electric power purchased/produced for motive power and...

  4. 49 CFR 1242.60 - Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Locomotive fuel, electric power purchased/produced for motive power and servicing locomotives (accounts XX-51-67, XX-51-68 and XX-51-69). 1242.60 Section...-Transportation § 1242.60 Locomotive fuel, electric power purchased/produced for motive power and...

  5. Fuel-free locomotion of Janus motors: magnetically induced thermophoresis.

    PubMed

    Baraban, Larysa; Streubel, Robert; Makarov, Denys; Han, Luyang; Karnaushenko, Dmitriy; Schmidt, Oliver G; Cuniberti, Gianaurelio

    2013-02-26

    We present fuel-free locomotion of magnetic spherical Janus motors driven by magnetically induced thermophoresis--a self-diffusive propulsion of an object in any liquid media due to a local temperature gradient. Within this approach an ac magnetic field is applied to induce thermophoretic motion of the objects via heating a magnetic cap of the particles, while an additional dc magnetic field is used to orient Janus motors and guide their motion on a long time scale. Full control over the motion is achieved due to specific properties of ultrathin 100-nm-thick Permalloy (Py, Fe₁₉Ni₈₁ alloys) magnetic films resulting in a topologically stable magnetic vortex state in the cap structure of Janus motors. Realized here magnetically induced thermophoretic locomotion does not require catalytic chemical reactions that imply toxic reagents. In this respect, we addressed and successfully solved one of the main shortcomings in the field of artificial motors, namely being fully controlled and remain biocompatible. Therefore, our approach is attractive for biotechnological in vitro assays and even in vivo operations, since the functioning of Janus motors offers low toxicity; it is not dependent on the presence of the fuel molecules in solution. Furthermore, the suggested magnetic ac excitation is superior compared to the previously proposed optically induced heating using lasers as it does not require transparent packaging.

  6. The human vestibulo-ocular reflex during linear locomotion

    NASA Technical Reports Server (NTRS)

    Moore, S. T.; Hirasaki, E.; Raphan, T.; Cohen, B.

    2001-01-01

    During locomotion, there is a translation and compensatory rotation of the head in both the vertical and horizontal planes. During moderate to fast walking (100 m/min), vertical head translation occurs at the frequency of stepping (2 Hz) and generates peak linear acceleration of 0.37 g. Lateral head translation occurs at the stride frequency (1 Hz) and generates peak linear acceleration of 0.1 g. Peak head pitch and yaw angular velocities are approximately 17 degrees/s. The frequency and magnitude of these head movements are within the operational range of both the linear and angular vestibulo-ocular reflex (IVOR and aVOR). Vertical eye movements undergo a phase reversal from near to far targets. When viewing a far (>1 m) target, vertical eye velocity is typical of an aVOR response; that is, it is compensatory for head pitch. At close viewing distances (<1 m), vertical eye velocity is in phase with head pitch and is compensatory for vertical head translation, suggesting that the IVOR predominantly generates the eye movement response. Horizontal head movements during locomotion occur at the stride frequency of 1 Hz, where the IVOR gain is low. Horizontal eye movements are compensatory for head yaw at all viewing distances and are likely generated by the aVOR.

  7. Locomotion and drag in wet and dry granular media

    NASA Astrophysics Data System (ADS)

    Goldman, Daniel; Kuckuk, Robyn; Sharpe, Sarah

    2015-03-01

    Many animals move within substrates such as soil and dry sand; the resistive properties of such granular materials (GM) can depend on water content and compaction, but little is known about how such parameters affect locomotion or the relevant physics of drag and penetration. We developed a system to create homogeneous wet GM of varying moisture content and compaction in quantities sufficient to study the burial and subsurface locomotion of the Ocellated skink (C. ocellatus) a desert-generalist lizard. X-ray imaging revealed that in wet and dry GM the lizard slowly buried (~ 30 seconds) propagating a wave from head to tail, while moving in a start-stop motion. During forward movement, the head oscillated, and the forelimb on the convex side of the body propelled the animal. Although body kinematics (and ``slip'') were similar in both substrates, the burial depth was smaller in wet GM. Penetration and drag force experiments on smooth cylinders revealed that wet GM was ~ 3 × more resistive than dry GM, suggesting that during burial the lizard operated near its maximum force producing capability and was thus constrained by environmental properties. work supported by NSF PoLS.

  8. Locomotion of chemically powered autonomous nanowire motors

    NASA Astrophysics Data System (ADS)

    Wang, Lin; Li, Longqiu; Li, Tianlong; Zhang, Guangyu; Sun, Qian

    2015-08-01

    Physical insights on the hydrodynamics and locomotion of self-propelled nanowire motor under nonequilibrium steady state are investigated using finite element method in accordance with hybrid molecular dynamics/multiparticle collision dynamics and rigid body dynamics. Nanowire motor is discretized into finite segments, and forces of solvent molecule acting on the motor are assumed to be the sum of forces acting on all segments of the motor. We show that the locomotion of nanowire motor is mainly determined by the imbalance forces acting on the catalytic and noncatalytic segments. The average velocity along the axis increases significantly as a function of time prior to reaching equilibrium. The length of nanowire motor shows negligible effect on the velocity of the motor. Preliminary experimental results are provided to validate the current model.

  9. Rehinging biflagellar locomotion in a viscous fluid.

    PubMed

    Spagnolie, Saverio E

    2009-10-01

    A means of swimming in a viscous fluid is presented, in which a swimmer with only two links rotates around a joint and then rehinges in a periodic fashion in what is here termed rehinging locomotion. This two-link rigid swimmer is shown to locomote with an efficiency similar to that of Purcell's well-studied three-link swimmer, but with a simpler morphology. The hydrodynamically optimal stroke of an analogous flexible biflagellated swimmer is also considered. The introduction of flexibility is found to increase the swimming efficiency by up to 520% as the body begins to exhibit wavelike dynamics, with an upper bound on the efficiency determined by a degeneracy in the limit of infinite flexibility.

  10. Using entropy measures to characterize human locomotion.

    PubMed

    Leverick, Graham; Szturm, Tony; Wu, Christine Q

    2014-12-01

    Entropy measures have been widely used to quantify the complexity of theoretical and experimental dynamical systems. In this paper, the value of using entropy measures to characterize human locomotion is demonstrated based on their construct validity, predictive validity in a simple model of human walking and convergent validity in an experimental study. Results show that four of the five considered entropy measures increase meaningfully with the increased probability of falling in a simple passive bipedal walker model. The same four entropy measures also experienced statistically significant increases in response to increasing age and gait impairment caused by cognitive interference in an experimental study. Of the considered entropy measures, the proposed quantized dynamical entropy (QDE) and quantization-based approximation of sample entropy (QASE) offered the best combination of sensitivity to changes in gait dynamics and computational efficiency. Based on these results, entropy appears to be a viable candidate for assessing the stability of human locomotion.

  11. Millipede-inspired locomotion through novel U-shaped piezoelectric motors

    NASA Astrophysics Data System (ADS)

    Avirovik, Dragan; Butenhoff, Bryan; Priya, Shashank

    2014-03-01

    We report a novel piezoelectric motor that operates at a resonance frequency of 144 Hz, much lower than that of conventional ultrasonic motors, and meets the displacement and gait requirements for designing the locomotion mechanism of a millipede-inspired robot (millibot). The motor structure consists of two piezoelectric bimorphs arranged in a U-shaped configuration. Using the first bending mode for both the piezoelectric bimorphs an elliptical motion was obtained at the tip which led to the successful implementation of millipede inspired locomotion. At an input voltage of 70.7 Vrms, the piezoelectric motor operating at resonance frequency was able to generate torque of 0.03 mN m, mechanical power of 0.84 mW and maximum velocity of 62 rad s-1. Detailed discussion is provided about the principle of operation of the millibot.

  12. Different forms of locomotion in the spinal lamprey.

    PubMed

    Hsu, Li-Ju; Orlovsky, Grigori N; Zelenin, Pavel V

    2014-06-01

    Forward locomotion has been extensively studied in different vertebrate animals, and the principal role of spinal mechanisms in the generation of this form of locomotion has been demonstrated. Vertebrate animals, however, are capable of other forms of locomotion, such as backward walking and swimming, sideward walking, and crawling. Do the spinal mechanisms play a principal role in the generation of these forms of locomotion? We addressed this question in lampreys, which are capable of five different forms of locomotion - fast forward swimming, slow forward swimming, backward swimming, forward crawling, and backward crawling. To induce locomotion in lampreys spinalised at the second gill level, we used either electrical stimulation of the spinal cord at different rostrocaudal levels, or tactile stimulation of specific cutaneous receptive fields from which a given form of locomotion could be evoked in intact lampreys. We found that any of the five forms of locomotion could be evoked in the spinal lamprey by electrical stimulation of the spinal cord, and some of them by tactile stimulation. These results suggest that spinal mechanisms in the lamprey, in the absence of phasic supraspinal commands, are capable of generating the basic pattern for all five forms of locomotion observed in intact lampreys. In spinal lampreys, the direction of swimming did not depend on the site of spinal cord stimulation, but on the stimulation strength. The direction of crawling strongly depended on the body configuration. The spinal structures presumably activated by spinal cord stimulation and causing different forms of locomotion are discussed.

  13. Network interneurons underlying ciliary locomotion in Hermissenda.

    PubMed

    Crow, Terry; Jin, Nan Ge; Tian, Lian-Ming

    2013-02-01

    In the nudibranch mollusk Hermissenda, ciliary locomotion contributes to the generation of two tactic behaviors. Light elicits a positive phototaxis, and graviceptive stimulation evokes a negative gravitaxis. Two classes of light-responsive premotor interneurons in the network contributing to ciliary locomotion have been recently identified in the cerebropleural ganglia. Aggregates of type I interneurons receive monosynaptic excitatory (I(e)) or inhibitory (I(i)) input from identified photoreceptors. Type II interneurons receive polysynaptic excitatory (II(e)) or inhibitory (II(i)) input from photoreceptors. The ciliary network also includes type III inhibitory (III(i)) interneurons, which form monosynaptic inhibitory connections with ciliary efferent neurons (CENs). Illumination of the eyes evokes a complex inhibitory postsynaptic potential, a decrease of I(i) spike activity, a complex excitatory postsynaptic potential, and an increase of I(e) spike activity. Here, we characterized the contribution of identified I, II, and III(i) interneurons to the neural network supporting visually guided locomotion. In dark-adapted preparations, light elicited an increase in the tonic spike activity of II(e) interneurons and a decrease in the tonic spike activity of II(i) interneurons. Fluorescent dye-labeled type II interneurons exhibited diverse projections within the circumesophageal nervous system. However, a subclass of type II interneurons, II(e(cp)) and II(i(cp)) interneurons, were shown to terminate within the ipsilateral cerebropleural ganglia and indirectly modulate the activity of CENs. Type II interneurons form monosynaptic or polysynaptic connections with previously identified components of the ciliary network. The identification of a monosynaptic connection between I(e) and III(i) interneurons shown here suggest that they provide a major role in the light-dependent modulation of CEN spike activity underlying ciliary locomotion.

  14. Trackways Produced by Lungfish During Terrestrial Locomotion

    PubMed Central

    Falkingham, Peter L.; Horner, Angela M.

    2016-01-01

    Some primarily aquatic vertebrates make brief forays onto land, creating traces as they do. A lack of studies on aquatic trackmakers raises the possibility that such traces may be ignored or misidentified in the fossil record. Several terrestrial Actinopterygian and Sarcopterygian species have previously been proposed as possible models for ancestral tetrapod locomotion, despite extant fishes being quite distinct from Devonian fishes, both morphologically and phylogenetically. Although locomotion has been well-studied in some of these taxa, trackway production has not. We recorded terrestrial locomotion of a 35 cm African lungfish (Protopterus annectens; Dipnoi: Sarcopterygii) on compliant sediment. Terrestrial movement in the lungfish is accomplished by planting the head and then pivoting the trunk. Impressions are formed where the head impacts the substrate, while the body and fins produce few traces. The head leaves a series of alternating left-right impressions, where each impact can appear as two separate semi-circular impressions created by the upper and lower jaws, bearing some similarity to fossil traces interpreted as footprints. Further studies of trackways of extant terrestrial fishes are necessary to understand the behavioural repertoire that may be represented in the fossil track record. PMID:27670758

  15. Trackways Produced by Lungfish During Terrestrial Locomotion.

    PubMed

    Falkingham, Peter L; Horner, Angela M

    2016-09-27

    Some primarily aquatic vertebrates make brief forays onto land, creating traces as they do. A lack of studies on aquatic trackmakers raises the possibility that such traces may be ignored or misidentified in the fossil record. Several terrestrial Actinopterygian and Sarcopterygian species have previously been proposed as possible models for ancestral tetrapod locomotion, despite extant fishes being quite distinct from Devonian fishes, both morphologically and phylogenetically. Although locomotion has been well-studied in some of these taxa, trackway production has not. We recorded terrestrial locomotion of a 35 cm African lungfish (Protopterus annectens; Dipnoi: Sarcopterygii) on compliant sediment. Terrestrial movement in the lungfish is accomplished by planting the head and then pivoting the trunk. Impressions are formed where the head impacts the substrate, while the body and fins produce few traces. The head leaves a series of alternating left-right impressions, where each impact can appear as two separate semi-circular impressions created by the upper and lower jaws, bearing some similarity to fossil traces interpreted as footprints. Further studies of trackways of extant terrestrial fishes are necessary to understand the behavioural repertoire that may be represented in the fossil track record.

  16. Disparity and convergence in bipedal archosaur locomotion

    PubMed Central

    Bates, K. T.; Schachner, E. R.

    2012-01-01

    This study aims to investigate functional disparity in the locomotor apparatus of bipedal archosaurs. We use reconstructions of hindlimb myology of extant and extinct archosaurs to generate musculoskeletal biomechanical models to test hypothesized convergence between bipedal crocodile-line archosaurs and dinosaurs. Quantitative comparison of muscle leverage supports the inference that bipedal crocodile-line archosaurs and non-avian theropods had highly convergent hindlimb myology, suggesting similar muscular mechanics and neuromuscular control of locomotion. While these groups independently evolved similar musculoskeletal solutions to the challenges of parasagittally erect bipedalism, differences also clearly exist, particularly the distinct hip and crurotarsal ankle morphology characteristic of many pseudosuchian archosaurs. Furthermore, comparative analyses of muscle design in extant archosaurs reveal that muscular parameters such as size and architecture are more highly adapted or optimized for habitual locomotion than moment arms. The importance of these aspects of muscle design, which are not directly retrievable from fossils, warns against over-extrapolating the functional significance of anatomical convergences. Nevertheless, links identified between posture, muscle moments and neural control in archosaur locomotion suggest that functional interpretations of osteological changes in limb anatomy traditionally linked to postural evolution in Late Triassic archosaurs could be constrained through musculoskeletal modelling. PMID:22112652

  17. Stepper motor drive for on load tapchanger in electric locomotive

    SciTech Connect

    Aruna Kumar, G.V.D.; Kumar, S.; Mishra, P.; Wadhonkar, N.K.

    1995-12-31

    Indian Railways have a fleet of 2,200 electrical locomotives running on 25 KV ac traction. An on-load tap changer is used to select voltage for speed control of dc traction motor. A four stroke reciprocating type air motor is used presently to drive the tap changer (GR). Complex gear and camshaft mechanism is used to move tap changer and to generate various logic signals for safe loco operation. The annual failure rate for tap changer and its drive is of the order of 20%. A microprocessor controlled stepper motor drive has been designed and constructed to drive the on-load tap changer. A current controlled chopper is used to drive the motor and control logic has been generated through an optimum hardware and software combination. The assembly has been tested on a prototype tap changer in the laboratory.

  18. Effect of Biodiesel Fuels on Real-World Emissions of Passenger Locomotives.

    PubMed

    Graver, Brandon M; Frey, H Christopher; Hu, Jiangchuan

    2016-11-01

    Few data are available regarding the effect of biodiesel on exhaust emission rates of two-stroke engines used in many passenger locomotives. Using a portable emissions measurement system (PEMS), duty cycle average nitrogen oxides (NOx), hydrocarbons (HC), carbon monoxide (CO), particulate matter (PM), and carbon dioxide (CO2) emission rates were measured for three locomotives operating on ultra-low sulfur diesel (ULSD) and soy-based B10, B20, and B40 biodiesel blends. Measurements were conducted in the rail yard (RY) and over-the-rail (OTR) during passenger service. Compared to ULSD, B20 biodiesel had statistically significant average emission rate reductions in the RY of 58% for CO, 45% for PM, and 6% CO2 and OTR of 59% for HC, 50% for CO, 26% for PM, and 5% for CO2. The average differences in NOx emission rates for both the RY and OTR, and HC in the RY, were not statistically significant. The OTR findings typically agreed qualitatively with the RY findings; however, OTR provides a better basis for estimating the real-world impact of fuel switching. The results indicate substantial potential to reduce in-use locomotive emissions for existing older locomotives, with the exception of NOx.

  19. FIM Imaging and FIMtrack: Two New Tools Allowing High-throughput and Cost Effective Locomotion Analysis

    PubMed Central

    Berh, Dimitri; Jiang, Xiaoyi; Klämbt, Christian

    2014-01-01

    The analysis of neuronal network function requires a reliable measurement of behavioral traits. Since the behavior of freely moving animals is variable to a certain degree, many animals have to be analyzed, to obtain statistically significant data. This in turn requires a computer assisted automated quantification of locomotion patterns. To obtain high contrast images of almost translucent and small moving objects, a novel imaging technique based on frustrated total internal reflection called FIM was developed. In this setup, animals are only illuminated with infrared light at the very specific position of contact with the underlying crawling surface. This methodology results in very high contrast images. Subsequently, these high contrast images are processed using established contour tracking algorithms. Based on this, we developed the FIMTrack software, which serves to extract a number of features needed to quantitatively describe a large variety of locomotion characteristics. During the development of this software package, we focused our efforts on an open source architecture allowing the easy addition of further modules. The program operates platform independent and is accompanied by an intuitive GUI guiding the user through data analysis. All locomotion parameter values are given in form of csv files allowing further data analyses. In addition, a Results Viewer integrated into the tracking software provides the opportunity to interactively review and adjust the output, as might be needed during stimulus integration. The power of FIM and FIMTrack is demonstrated by studying the locomotion of Drosophila larvae. PMID:25591081

  20. Peripheral multidendritic sensory neurons are necessary for rhythmic locomotion behavior in Drosophila larvae

    PubMed Central

    Song, Wei; Onishi, Maika; Jan, Lily Yeh; Jan, Yuh Nung

    2007-01-01

    From breathing to walking, rhythmic movements encompass physiological processes important across the entire animal kingdom. It is thought by many that the generation of rhythmic behavior is operated by a central pattern generator (CPG) and does not require peripheral sensory input. Sensory feedback is, however, required to modify or coordinate the motor activity in response to the circumstances of actual movement. In contrast to this notion, we report here that sensory input is necessary for the generation of Drosophila larval locomotion, a form of rhythmic behavior. Blockage of all peripheral sensory inputs resulted in cessation of larval crawling. By conditionally silencing various subsets of larval peripheral sensory neurons, we identified the multiple dendritic (MD) neurons as the neurons essential for the generation of rhythmic peristaltic locomotion. By recording the locomotive motor activities, we further demonstrate that removal of MD neuron input disrupted rhythmic motor firing pattern in a way that prolonged the stereotyped segmental motor firing duration and prevented the propagation of posterior to anterior segmental motor firing. These findings reveal that MD sensory neuron input is a necessary component in the neural circuitry that generates larval locomotion. PMID:17360325

  1. Neurobiology of Caenorhabditis elegans Locomotion: Where Do We Stand?

    PubMed Central

    Gjorgjieva, Julijana; Biron, David; Haspel, Gal

    2014-01-01

    Animals use a nervous system for locomotion in some stage of their life cycle. The nematode Caenorhabditis elegans, a major animal model for almost all fields of experimental biology, has long been used for detailed studies of genetic and physiological locomotion mechanisms. Of its 959 somatic cells, 302 are neurons that are identifiable by lineage, location, morphology, and neurochemistry in every adult hermaphrodite. Of those, 75 motoneurons innervate body wall muscles that provide the thrust during locomotion. In this Overview, we concentrate on the generation of either forward- or backward-directed motion during crawling and swimming. We describe locomotion behavior, the parts constituting the locomotion system, and the relevant neuronal connectivity. Because it is not yet fully understood how these components combine to generate locomotion, we discuss competing hypotheses and models. PMID:26955070

  2. A contribution about ferrofluid based flow manipulation and locomotion systems

    NASA Astrophysics Data System (ADS)

    Zimmermann, K.; Zeidis, I.; Bohm, V.; Popp, J.

    2009-02-01

    With the background of developing apedal bionic inspired locomotion systems for future application fields like autonomous (swarm) robots, medical engineering and inspection systems, this article presents a selection of locomotion systems with bifluidic flow control using ferrofluid. By controlling the change of shape, position and pressure of the ferrofluid in a secondary low viscous fluid by magnetic fields locomotion of objects or the ferrofluid itself can be realised. The locomotion of an object is caused in the first example by a ferrofluid generated flow of the secondary fluid and in the second and third case by the direct alteration of the ferrofluid position.

  3. Operations

    ERIC Educational Resources Information Center

    Wilkins, Jesse L. M.; Norton, Anderson; Boyce, Steven J.

    2013-01-01

    Previous research has documented schemes and operations that undergird students' understanding of fractions. This prior research was based, in large part, on small-group teaching experiments. However, written assessments are needed in order for teachers and researchers to assess students' ways of operating on a whole-class scale. In this study,…

  4. Authorized Limits for the Release of a 25 Ton Locomotive, Serial Number 21547, at the Area 25 Engine Maintenance, Assembly, and Disassembly Facility, Nevada Test Site, Nevada

    SciTech Connect

    Jeremy Gwin and Douglas Frenette

    2010-04-08

    This document contains process knowledge and radiological data and analysis to support approval for release of the 25-ton locomotive, Serial Number 21547, at the Area 25 Engine Maintenance, Assembly, and Disassembly (EMAD) Facility, located on the Nevada Test Site (NTS). The 25-ton locomotive is a small, one-of-a-kind locomotive used to move railcars in support of the Nuclear Engine for Rocket Vehicle Application project. This locomotive was identified as having significant historical value by the Nevada State Railroad Museum in Boulder City, Nevada, where it will be used as a display piece. A substantial effort to characterize the radiological conditions of the locomotive was undertaken by the NTS Management and Operations Contractor, National Security Technologies, LLC (NSTec). During this characterization process, seven small areas on the locomotive had contamination levels that exceeded the NTS release criteria (limits consistent with U.S. Department of Energy [DOE] Order DOE O 5400.5, “Radiation Protection of the Public and the Environment”). The decision was made to perform radiological decontamination of these known accessible impacted areas to further the release process. On February 9, 2010, NSTec personnel completed decontamination of these seven areas to within the NTS release criteria. Although all accessible areas of the locomotive had been successfully decontaminated to within NTS release criteria, it was plausible that inaccessible areas of the locomotive (i.e., those areas on the locomotive where it was not possible to perform radiological surveys) could potentially have contamination above unrestricted release limits. To access the majority of these inaccessible areas, the locomotive would have to be disassembled. A complete disassembly for a full radiological survey could have permanently destroyed parts and would have ruined the historical value of the locomotive. Complete disassembly would also add an unreasonable financial burden for the

  5. Delayed and lasting effects of deep brain stimulation on locomotion in Parkinson's disease

    NASA Astrophysics Data System (ADS)

    Beuter, Anne; Modolo, Julien

    2009-06-01

    Parkinson's disease (PD) is a neurodegenerative disorder characterized by a variety of motor signs affecting gait, postural stability, and tremor. These symptoms can be improved when electrodes are implanted in deep brain structures and electrical stimulation is delivered chronically at high frequency (>100 Hz). Deep brain stimulation (DBS) onset or cessation affects PD signs with different latencies, and the long-term improvements of symptoms affecting the body axis and those affecting the limbs vary in duration. Interestingly, these effects have not been systematically analyzed and modeled. We compare these timing phenomena in relation to one axial (i.e., locomotion) and one distal (i.e., tremor) signs. We suggest that during DBS, these symptoms are improved by different network mechanisms operating at multiple time scales. Locomotion improvement may involve a delayed plastic reorganization, which takes hours to develop, whereas rest tremor is probably alleviated by an almost instantaneous desynchronization of neural activity in subcortical structures. Even if all PD patients develop both distal and axial symptoms sooner or later, current computational models of locomotion and rest tremor are separate. Furthermore, a few computational models of locomotion focus on PD and none exploring the effect of DBS was found in the literature. We, therefore, discuss a model of a neuronal network during DBS, general enough to explore the subcircuits controlling locomotion and rest tremor simultaneously. This model accounts for synchronization and plasticity, two mechanisms that are believed to underlie the two types of symptoms analyzed. We suggest that a hysteretic effect caused by DBS-induced plasticity and synchronization modulation contributes to the different therapeutic latencies observed. Such a comprehensive, generic computational model of DBS effects, incorporating these timing phenomena, should assist in developing a more efficient, faster, durable treatment of

  6. Optimal locomotion of mechanical rectifier systems

    NASA Astrophysics Data System (ADS)

    Blair, Justin T.

    Vehicles utilizing animal locomotion mechanisms may possess increased performance parameters and the ability to overcome more difficult terrain than conventional wheel or propeller driven vehicles. The essential mechanism underlying animal locomotion can be viewed as mechanical rectification that converts periodic body movements to thrust force through interactions with the environment. This dissertation defines a general class of mechanical rectifiers as multi-body systems equipped with such thrust generation mechanisms. A general model is developed from the Euler-Lagrange equation and simplified by assuming small body oscillations around a given nominal posture. The model reveals that the rectifying dynamics can be captured by a bilinear (but not linear) term of body shape variables. An optimal gait problem is formulated for the bilinear rectifier model as a minimization of a quadratic cost function over the set of periodic functions subject to a constraint on the average locomotion velocity. We prove that a globally optimal solution is given by a harmonic gait that can be found by generalized eigenvalue computation with a line search over cycle frequencies. We verify the solution method through case studies of a two dimensional chain of links for which snake-like undulations and jellyfish-like flapping gaits are found to be optimal, and obtain analytical insights into determinants of optimal gaits from a simple disk-mass rectifier system. Lastly, we develop a dynamic model for batoid swimming featuring a 6 degree-of-freedom main body (position and orientation), with independent wing deformation (described as the motion of many discrete points in the body-fixed coordinate frame), and calculate various gaits. Multiple wing shapes and optimality criteria are considered, such as the maximum thrust to deflection ratio or minimum input power, and the resulting gaits are compared.

  7. Biomedical perspectives on locomotion in null gravity

    NASA Technical Reports Server (NTRS)

    Cavanagh, Peter R.

    1989-01-01

    A number of important features of various locomotor activities are discussed, and approaches to the study of these activities in the context of space flight are suggested. In particular, the magnitude of peak forces and the rates of change of force during terrestrial cycling, walking, and running are compared. It is shown that subtle changes in the conditions and techniques of locomotion can have a major influence on the biomechanical consequences to the skeleton. The various hypotheses that identify locomotor exercise as a countermeasure to bone demineralization during weightlessness deserve to be tested with some degree of biomechanical rigor. Various approaches for achieving such scrutiny are discussed.

  8. Hamiltonian mechanics and planar fishlike locomotion

    NASA Astrophysics Data System (ADS)

    Kelly, Scott; Xiong, Hailong; Burgoyne, Will

    2007-11-01

    A free deformable body interacting with a system of point vortices in the plane constitutes a Hamiltonian system. A free Joukowski foil with variable camber shedding point vortices in an ideal fluid according to a periodically applied Kutta condition provides a model for fishlike locomotion which bridges the gap between inviscid analytical models that sacrifice realism for tractability and viscous computational models inaccessible to tools from nonlinear control theory. We frame such a model in the context of Hamiltonian mechanics and describe its relevance both to the study of hydrodynamic interactions within schools of fish and to the realization of model-based control laws for biomimetic autonomous robotic vehicles.

  9. Enhanced Spatial Resolution During Locomotion and Heightened Attention in Mouse Primary Visual Cortex

    PubMed Central

    Mineault, Patrick J.; Tring, Elaine; Trachtenberg, Joshua T.

    2016-01-01

    We do not fully understand how behavioral state modulates the processing and transmission of sensory signals. Here, we studied the cortical representation of the retinal image in mice that spontaneously switched between a state of rest and a constricted pupil, and one of active locomotion and a dilated pupil, indicative of heightened attention. We measured the selectivity of neurons in primary visual cortex for orientation and spatial frequency, as well as their response gain, in these two behavioral states. Consistent with prior studies, we found that preferred orientation and spatial frequency remained invariant across states, whereas response gain increased during locomotion relative to rest. Surprisingly, relative gain, defined as the ratio between the gain during locomotion and the gain during rest, was not uniform across the population. Cells tuned to high spatial frequencies showed larger relative gain compared with those tuned to lower spatial frequencies. The preferential enhancement of high-spatial-frequency information was also reflected in our ability to decode the stimulus from population activity. Finally, we show that changes in gain originate from shifts in the operating point of neurons along a spiking nonlinearity as a function of behavioral state. Differences in the relative gain experienced by neurons with high and low spatial frequencies are due to corresponding differences in how these cells shift their operating points between behavioral states. SIGNIFICANCE STATEMENT How behavioral state modulates the processing and transmission of sensory signals remains poorly understood. Here, we show that the mean firing rate and neuronal gain increase during locomotion as a result in a shift of the operating point of neurons. We define relative gain as the ratio between the gain of neurons during locomotion and rest. Interestingly, relative gain is higher in cells with preferences for higher spatial frequencies than those with low

  10. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  11. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  12. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 25 2014-07-01 2014-07-01 false Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  13. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  14. 40 CFR Appendix A to Subpart A of... - Switcher Locomotives

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 26 2012-07-01 2011-07-01 true Switcher Locomotives A Appendix A to Subpart A of Part 201 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE... Provisions Pt. 201, Subpt. A, App. A Appendix A to Subpart A of Part 201—Switcher Locomotives Type...

  15. Goal Directed Locomotion and Balance Control in Autistic Children

    ERIC Educational Resources Information Center

    Vernazza-Martin, S.; Martin, N.; Vernazza, A.; Lepellec-Muller, A.; Rufo, M.; Massion, J.; Assaiante, C.

    2005-01-01

    This article focuses on postural anticipation and multi-joint coordination during locomotion in healthy and autistic children. Three questions were addressed: (1) Are gait parameters modified in autistic children? (2) Is equilibrium control affected in autistic children? (3) Is locomotion adjusted to the experimenter-imposed goal? Six healthy…

  16. [Transdisciplinary Approach for Sarcopenia. Sarcopenia and Locomotive syndrome].

    PubMed

    Endo, Naoto

    2014-10-01

    Locomotive syndrome refers to a condition under which the elderly has transfer-difficulties by problems of the locomotive organs. Sarcopenia and osteoporosis are a cause of care requirement and bedridden status. To evaluate and manage these disabled elderly with osteoporosis or sarcopenia, multidisciplinary approach is important.

  17. [Preventive and therapeutic approach to the locomotive syndrome].

    PubMed

    Akune, Toru

    2013-01-01

    The locomotive syndrome is a serious health condition that places the elderly at high risk of requiring support and long-term care caused by common age-related musculoskeletal disorders such as osteoporosis, osteoarthritis and sarcopenia. Accumulation of epidemiological evidence is required for the prevention strategy of the locomotive syndrome. Exercise intervention may be useful for the treatment of this condition.

  18. The relationship between transitional motor skills and locomotion.

    PubMed

    Looper, Julia; Talbot, Sara; Link, Allison; Chandler, Lynette

    2015-02-01

    This study explores whether transitional skills and sitting correlate with locomotion onset. The development of eight infants was followed. Most transitional skills correlated with locomotor skills. Sitting and rolling did not. Transitional skills may resemble the control needed for locomotion more closely than sitting.

  19. Locomotion Induced by Spatial Restriction in Adult Drosophila

    PubMed Central

    Xiao, Chengfeng; Robertson, R. Meldrum

    2015-01-01

    Drosophila adults display an unwillingness to enter confined spaces but the behaviors induced by spatial restriction in Drosophila are largely unknown. We developed a protocol for high-throughput analysis of locomotion and characterized features of locomotion in a restricted space. We observed intense and persistent locomotion of flies in small circular arenas (diameter 1.27 cm), whereas locomotion was greatly reduced in large circular arenas (diameter 3.81 cm). The increased locomotion induced by spatial restriction was seen in male flies but not female flies, indicating sexual dimorphism of the response to spatial restriction. In large arenas, male flies increased locomotion in arenas previously occupied by male but not female individuals. In small arenas, such pre-conditioning had no effect on male flies, which showed intense and persistent locomotion similar to that seen in fresh arenas. During locomotion with spatial restriction, wildtype Canton-S males traveled slower and with less variation in speed than the mutant w1118 carrying a null allele of white gene. In addition, wildtype flies showed a stronger preference for the boundary than the mutant in small arenas. Genetic analysis with a series of crosses revealed that the white gene was not associated with the phenotype of boundary preference in wildtype flies. PMID:26351842

  20. Economic assessment of coal-burning locomotives: Topical report

    SciTech Connect

    Not Available

    1986-02-01

    The General Electric Company embarked upon a study to evaluate various alternatives for the design and manufacture a coal fired locomotive considering various prime movers, but retaining the electric drive transmission. The initial study was supported by the Burlington-Northern and Norfolk-Southern railroads, and included the following alternatives: coal fired diesel locomotive; direct fired gas turbine locomotives; direct fired gas turbine locomotive with steam injection; raw coal gasifier gas turbine locomotive; and raw coal fluid bed steam turbine locomotive. All alternatives use the electric drive transmission and were selected for final evaluation. The first three would use a coal water slurry as a fuel, which must be produced by new processing plants. Therefore, use of a slurry would require a significant plant capital investment. The last two would use classified run-of-the-mine (ROM) coal with much less capital expenditure. Coal fueling stations would be required but are significantly lower in capital cost than a coal slurry plant. For any coal fired locomotive to be commercially viable, it must pass the following criteria: be technically feasible and environmentally acceptable; meet railroads' financial expectations; and offer an attractive return to the locomotive manufacturer. These three criteria are reviewed in the report.

  1. 40 CFR 92.104 - Locomotive and engine testing; overview.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Locomotive and engine testing; overview. 92.104 Section 92.104 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR....104 Locomotive and engine testing; overview. (a) The test procedures described here...

  2. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Tenders Trucks, Frames and Equalizing System § 230.106 Steam locomotive frame. (a) Maintenance and inspection. Frames, decks, plates, tailpieces, pedestals, and braces shall be maintained in a safe and... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive frame. 230.106 Section...

  3. Amoeba proteus displays a walking form of locomotion.

    PubMed

    Cameron, Ivan; Rinaldi, Robert A; Kirby, Gerald; Davidson, David

    2007-08-01

    This report deals with observations on the directional locomotion of amoeba before and after fixation and scanning electron microscopy. The study was aimed at visualization of the stepwise events of directional movements. After the analysis of the data it is proposed that the amoeba undergoes a sequence of movement events that can be defined as a walking form of locomotion.

  4. 49 CFR 229.121 - Locomotive cab noise.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) of this section, a railroad shall not make any alterations that cause the average sound level for that locomotive design or model to exceed: (i) 82 dB(A) if the average sound level for a locomotive design or model is less than 82 dB(A); or (ii) 85 dB(A) if the average sound level for a...

  5. 49 CFR 229.121 - Locomotive cab noise.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) of this section, a railroad shall not make any alterations that cause the average sound level for that locomotive design or model to exceed: (i) 82 dB(A) if the average sound level for a locomotive design or model is less than 82 dB(A); or (ii) 85 dB(A) if the average sound level for a...

  6. Looking north toward Locomotive Shop (2 tracks on left), Car ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Looking north toward Locomotive Shop (2 tracks on left), Car Shop on right, and flat car in foreground. Note locomotive and car tires leaning on stock shed at left - East Broad Top Railroad & Coal Company, State Route 994, West of U.S. Route 522, Rockhill Furnace, Huntingdon County, PA

  7. 77 FR 30047 - Petition for Alternative Locomotive Crashworthiness Design

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ... Federal Railroad Administration Petition for Alternative Locomotive Crashworthiness Design In accordance... design for an electric locomotive, Model ACS-64, built by Siemens Industry, Inc. This request is made in...-0036. The alternative design incorporates crash energy management features, detailed in the...

  8. 40 CFR 1033.230 - Grouping locomotives into engine families.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... families. 1033.230 Section 1033.230 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Certifying Engine Families § 1033.230 Grouping locomotives into engine families. (a) Divide your product line into engine families of...

  9. 49 CFR 223.11 - Requirements for existing locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Requirements for existing locomotives. 223.11 Section 223.11 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION SAFETY GLAZING STANDARDS-LOCOMOTIVES, PASSENGER CARS AND...

  10. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRAKE SYSTEM SAFETY STANDARDS FOR FREIGHT AND OTHER NON-PASSENGER... reservoir on locomotives and related piping shall be zero, unless the system is capable of maintaining the... equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the...

  11. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION BRAKE SYSTEM SAFETY STANDARDS FOR FREIGHT AND OTHER NON-PASSENGER... reservoir on locomotives and related piping shall be zero, unless the system is capable of maintaining the... equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the...

  12. Whole-body vibration and ergonomic study of US railroad locomotives

    NASA Astrophysics Data System (ADS)

    Johanning, Eckardt; Landsbergis, Paul; Fischer, Siegfried; Christ, Eberhard; Göres, Benno; Luhrman, Raymond

    2006-12-01

    US locomotive operators have exposure to multi-axis whole-body vibration (WBV) and shocks while seated. This study assessed operator-related and ergonomic seating design factors that may have confounding or mitigating influence on WBV exposure and its effects. Vibration exposure was measured according to international guidelines (ISO 2631-1; 1997); ergonomic work place factors and vibration effects were studied with a cross-sectional survey instrument distributed to a randomly selected group of railroad engineers ( n=2546) and a control group; and during vehicle inspections. The survey response rate was 47% for the RR engineers ( n=1195) and 41% for the controls ( n=323). Results of the mean basic vibration measurements were for the x, y, z-direction and vector sum 0.14, 0.22, 0.28 and 0.49 m/s 2 respectively; almost all crest factors (CF), MTVV and VDV values were above the critical ratios given in ISO 2631-1. The prevalence of serious neck and lower back disorders among locomotive engineers was found to be nearly double that of the sedentary control group without such exposure. Railroad engineers rated their seats mostly unacceptable regarding different adjustment and comfort aspects (3.02-3.51; scale 1=excellent to 4=unacceptable), while the control group rated their chairs more favorably (1.96-3.44). Existing cab and seat design in locomotives can result in prolonged forced awkward spinal posture of the operator combined with WBV exposure. In a logistic regression analysis, time at work being bothered by vibration (h/day) was significantly associated with an increased risk of low back pain, shoulder and neck pain, and sciatic pain among railroad engineers. Customized vibration attenuation seats and improved cab design of the locomotive controls should be further investigated.

  13. Evolution of microorganism locomotion induced by starvation

    NASA Astrophysics Data System (ADS)

    Sibona, G. J.

    2007-07-01

    The search strategies of many organisms play a fundamental role in their competition to survive in a given environment. In this context, the propulsion systems of microorganisms have evolved during life history, to optimize the suitable use of energy they take from nutrients. Starting from a model for the motion of Brownian objects with internal energy depot, we show that the propulsion system of microorganisms has an optimal regimen while searching for new sources of food. Bacteria with a too low or too high energy expenditure in propulsion, moving in a nutrient-depleted environment, do not reach remote distances. In this sense, the mean square displacement has a maximum for a finite value of the propulsion rate. Species using the most efficient locomotion system have a considerable advantage for survival in hostile environments, a common situation in the ocean. Moreover, we found the existence of a lower size limit for useful locomotion. This suggests that, for organisms whose linear dimensions are below a certain threshold, it is advantageous not to use any propulsion mechanism at all, a result that is in agreement with what is observed in nature.

  14. Locomotion of a flapping flexible plate

    NASA Astrophysics Data System (ADS)

    Hua, Ru-Nan; Zhu, Luoding; Lu, Xi-Yun

    2013-12-01

    The locomotion of a flapping flexible plate in a viscous incompressible stationary fluid is numerically studied by an immersed boundary-lattice Boltzmann method for the fluid and a finite element method for the plate. When the leading-edge of the flexible plate is forced to heave sinusoidally, the entire plate starts to move freely as a result of the fluid-structure interaction. Mechanisms underlying the dynamics of the plate are elucidated. Three distinct states of the plate motion are identified and can be described as forward, backward, and irregular. Which state to occur depends mainly on the heaving amplitude and the bending rigidity of the plate. In the forward motion regime, analysis of the dynamic behaviors of the flapping flexible plate indicates that a suitable degree of flexibility can improve the propulsive performance. Moreover, there exist two kinds of vortex streets in the downstream of the plate which are normal and deflected wake. Further the forward motion is compared with the flapping-based locomotion of swimming and flying animals. The results obtained in the present study are found to be consistent with the relevant observations and measurements and can provide some physical insights into the understanding of the propulsive mechanisms of swimming and flying animals.

  15. Intrathecal application of cyproheptadine impairs locomotion in intact rats.

    PubMed

    Majczyński, Henryk; Cabaj, Anna; Górska, Teresa

    In intact adult rats, cyproheptadine, a 5-HT2 antagonist, administered intrathecally at the midlumbar segments was found to impair hindlimb locomotor movements during overground locomotion. These effects were dose-dependent; they varied from transient complete hindlimb paraplegia seen at doses of 300 microg/20 microl, to short-lasting trunk instability at doses of 100 microg/20 microl. After the return of overground locomotion, transient abduction of one of the hindlimbs was observed in some animals. These findings demonstrate that the blockade of 5-HT2 receptors affects locomotion in intact rats. Our results provide support for the hypothesis of serotonergic involvement in rat locomotion, which, so far, has been based mainly on the effects of 5-HT2 agonists on the recovery of locomotion in spinal rats.

  16. Sensory feedback in cockroach locomotion: current knowledge and open questions.

    PubMed

    Ayali, A; Couzin-Fuchs, E; David, I; Gal, O; Holmes, P; Knebel, D

    2015-09-01

    The American cockroach, Periplaneta americana, provides a successful model for the study of legged locomotion. Sensory regulation and the relative importance of sensory feedback vs. central control in animal locomotion are key aspects in our understanding of locomotive behavior. Here we introduce the cockroach model and describe the basic characteristics of the neural generation and control of walking and running in this insect. We further provide a brief overview of some recent studies, including mathematical modeling, which have contributed to our knowledge of sensory control in cockroach locomotion. We focus on two sensory mechanisms and sense organs, those providing information related to loading and unloading of the body and the legs, and leg-movement-related sensory receptors, and present evidence for the instrumental role of these sensory signals in inter-leg locomotion control. We conclude by identifying important open questions and indicate future perspectives.

  17. 49 CFR 229.207 - New locomotive crashworthiness design standards and changes to existing FRA-approved locomotive...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false New locomotive crashworthiness design standards and changes to existing FRA-approved locomotive crashworthiness design standards. 229.207 Section 229.207 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL...

  18. Development of an Environment-Aware Locomotion Mode Recognition System for Powered Lower Limb Prostheses.

    PubMed

    Liu, Ming; Wang, Ding; Helen Huang, He

    2016-04-01

    This paper aimed to develop and evaluate an environment-aware locomotion mode recognition system for volitional control of powered artificial legs. A portable terrain recognition (TR) module, consisting of an inertia measurement unit and a laser distance meter, was built to identify the type of terrain in front of the wearer while walking. A decision tree was used to classify the terrain types and provide either coarse or refined information about the walking environment. Then, the obtained environmental information was modeled as a priori probability and was integrated with a neuromuscular-mechanical-fusion-based locomotion mode (LM) recognition system. The designed TR module and environmental-aware LM recognition system was evaluated separately on able-bodied subjects and a transfemoral amputee online. The results showed that the TR module provided high quality environmental information: TR accuracy is above 98% and terrain transitions are detected over 500 ms before the time required to switch the prosthesis control mode. This enabled smooth locomotion mode transitions for the wearers. The obtained environmental information further improved the performance of LM recognition system, regardless of whether coarse or refined information was used. In addition, the environment-aware LM recognition system produced reliable online performance when the TR output was relatively noisy, which indicated the potential of this system to operate in unconstructed environment. This paper demonstrated that environmental information should be considered for operating wearable lower limb robotic devices, such as prosthetics and orthotics.

  19. Reactive and anticipatory control of posture and bipedal locomotion in a nonhuman primate.

    PubMed

    Mori, Futoshi; Nakajima, Katsumi; Tachibana, Atsumichi; Takasu, Chijiko; Mori, Masahiro; Tsujimoto, Toru; Tsukada, Hideo; Mori, Shigemi

    2004-01-01

    Bipedal locomotion is a common daily activity. Despite its apparent simplicity, it is a complex set of movements that requires the integrated neural control of multiple body segments. We have recently shown that the juvenile Japanese monkey, M. fuscata, can be operant-trained to walk bipedally on moving treadmill. It can control the body axis and lower limb movements when confronted by a change in treadmill speed. M. fuscata can also walk bipedally on a slanted treadmill. Furthermore, it can learn to clear an obstacle attached to the treadmill's belt. When failing to clear the obstacle, the monkey stumbles but quickly corrects its posture and the associated movements of multiple motor segments to again resume smooth bipedal walking. These results give indication that in learning to walk bipedally, M. fuscata transforms relevant visual, vestibular, proprioceptive, and exteroceptive sensory inputs into commands that engage both anticipatory and reactive motor mechanisms. Both mechanisms are essential for meeting external demands imposed upon posture and locomotion.

  20. Life-Cycle Assessment of the Use of Jatropha Biodiesel in Indian Locomotives (Revised)

    SciTech Connect

    Whitaker, M.; Heath, G.

    2009-03-01

    With India's transportation sector relying heavily on imported petroleum-based fuels, the Planning Commission of India and the Indian government recommended the increased use of blended biodiesel in transportation fleets, identifying Jatropha as a potentially important biomass feedstock. The Indian Oil Corporation and Indian Railways are collaborating to increase the use of biodiesel blends in Indian locomotives with blends of up to B20, aiming to reduce GHG emissions and decrease petroleum consumption. To help evaluate the potential for Jatropha-based biodiesel in achieving sustainability and energy security goals, this study examines the life cycle, net GHG emission, net energy ratio, and petroleum displacement impacts of integrating Jatropha-based biodiesel into locomotive operations in India. In addition, this study identifies the parameters that have the greatest impact on the sustainability of the system.

  1. Fish Locomotion: Recent Advances and New Directions

    NASA Astrophysics Data System (ADS)

    Lauder, George V.

    2015-01-01

    Research on fish locomotion has expanded greatly in recent years as new approaches have been brought to bear on a classical field of study. Detailed analyses of patterns of body and fin motion and the effects of these movements on water flow patterns have helped scientists understand the causes and effects of hydrodynamic patterns produced by swimming fish. Recent developments include the study of the center-of-mass motion of swimming fish and the use of volumetric imaging systems that allow three-dimensional instantaneous snapshots of wake flow patterns. The large numbers of swimming fish in the oceans and the vorticity present in fin and body wakes support the hypothesis that fish contribute significantly to the mixing of ocean waters. New developments in fish robotics have enhanced understanding of the physical principles underlying aquatic propulsion and allowed intriguing biological features, such as the structure of shark skin, to be studied in detail.

  2. Hydrodynamics and control of microbial locomotion

    NASA Astrophysics Data System (ADS)

    Dunkel, Jorn; Kantsler, Vasily; Polin, Marco; Wioland, Hugo; Goldstein, Raymond

    2014-03-01

    Interactions between swimming cells, surfaces and fluid flow are essential to many microbiological processes, from the formation of biofilms to the fertilization of human egg cells. Yet, relatively little remains known quantitatively about the physical mechanisms that govern the response of bacteria, algae and sperm cells to flow velocity gradients and solid surfaces. A better understanding of cell-surface and cell-flow interactions promises new biological insights and may advance microfluidic techniques for controlling microbial and sperm locomotion, with potential applications in diagnostics and therapeutic protein synthesis. Here, we report new experimental measurements that quantify surface interactions of bacteria, unicellular green algae and mammalian spermatozoa. These experiments show that the subtle interplay of hydrodynamics and surface interactions can stabilize collective bacterial motion, that direct ciliary contact interactions dominate surface scattering of eukaryotic biflagellate algae, and that rheotaxis combined with steric surface interactions provides a robust long-range navigation mechanism for sperm cells.

  3. Fish locomotion: recent advances and new directions.

    PubMed

    Lauder, George V

    2015-01-01

    Research on fish locomotion has expanded greatly in recent years as new approaches have been brought to bear on a classical field of study. Detailed analyses of patterns of body and fin motion and the effects of these movements on water flow patterns have helped scientists understand the causes and effects of hydrodynamic patterns produced by swimming fish. Recent developments include the study of the center-of-mass motion of swimming fish and the use of volumetric imaging systems that allow three-dimensional instantaneous snapshots of wake flow patterns. The large numbers of swimming fish in the oceans and the vorticity present in fin and body wakes support the hypothesis that fish contribute significantly to the mixing of ocean waters. New developments in fish robotics have enhanced understanding of the physical principles underlying aquatic propulsion and allowed intriguing biological features, such as the structure of shark skin, to be studied in detail.

  4. Adaptation to suspensory locomotion in Australopithecus sediba.

    PubMed

    Rein, Thomas R; Harrison, Terry; Carlson, Kristian J; Harvati, Katerina

    2017-03-01

    Australopithecus sediba is represented by well-preserved fossilized remains from the locality of Malapa, South Africa. Recent work has shown that the combination of features in the limb skeleton of A. sediba was distinct from that of earlier species of Australopithecus, perhaps indicating that this species moved differently. The bones of the arm and forearm indicate that A. sediba was adapted to suspensory and climbing behaviors. We used a geometric morphometric approach to examine ulnar shape, potentially identifying adaptations to forelimb suspensory locomotion in A. sediba. Results indicated suspensory capabilities in this species and a stronger forelimb suspensory signal than has been documented in Australopithecus afarensis. Our study confirms the adaptive significance of functional morphological traits for arboreal movements in the locomotor repertoire of A. sediba and provides important insight into the diversity and mosaic nature of locomotor adaptations among early hominins.

  5. The Effect of Increasing Mass upon Locomotion

    NASA Technical Reports Server (NTRS)

    DeWitt, John; Hagan, Donald

    2007-01-01

    The purpose of this investigation was to determine if increasing body mass while maintaining bodyweight would affect ground reaction forces and joint kinetics during walking and running. It was hypothesized that performing gait with increased mass while maintaining body weight would result in greater ground reaction forces, and would affect the net joint torques and work at the ankle, knee and hip when compared to gait with normal mass and bodyweight. Vertical ground reaction force was measured for ten subjects (5M/5F) during walking (1.34 m/s) and running (3.13 m/s) on a treadmill. Subjects completed one minute of locomotion at normal mass and bodyweight and at four added mass (AM) conditions (10%, 20%, 30% and 40% of body mass) in random order. Three-dimensional joint position data were collected via videography. Walking and running were analyzed separately. The addition of mass resulted in several effects. Peak impact forces and loading rates increased during walking, but decreased during running. Peak propulsive forces decreased during walking and did not change during running. Stride time increased and hip extensor angular impulse and positive work increased as mass was added for both styles of locomotion. Work increased at a greater rate during running than walking. The adaptations to additional mass that occur during walking are different than during running. Increasing mass during exercise in microgravity may be beneficial to increasing ground reaction forces during walking and strengthening hip musculature during both walking and running. Future study in true microgravity is required to determine if the adaptations found would be similar in a weightless environment.

  6. Dynamic legged locomotion in robots and animals

    NASA Astrophysics Data System (ADS)

    Raibert, Marc; Playter, Robert; Ringrose, Robert; Bailey, Dave; Leeser, Karl

    1995-01-01

    This report documents our study of active legged systems that balance actively and move dynamically. The purpose of this research is to build a foundation of knowledge that can lead both to the construction of useful legged vehicles and to a better understanding of how animal locomotion works. In this report we provide an update on progress during the past year. Here are the topics covered in this report: (1) Is cockroach locomotion dynamic? To address this question we created three models of cockroaches, each abstracted at a different level. We provided each model with a control system and computer simulation. One set of results suggests that 'Groucho Running,' a type of dynamic walking, seems feasible at cockroach scale. (2) How do bipeds shift weight between the legs? We built a simple planar biped robot specifically to explore this question. It shifts its weight from one curved foot to the other, using a toe-off and toe-on strategy, in conjunction with dynamic tipping. (3) 3D biped gymnastics: The 3D biped robot has done front somersaults in the laboratory. The robot changes its leg length in flight to control rotation rate. This in turn provides a mechanism for controlling the landing attitude of the robot once airborne. (4) Passively stabilized layout somersault: We have found that the passive structure of a gymnast, the configuration of masses and compliances, can stabilize inherently unstable maneuvers. This means that body biomechanics could play a larger role in controlling behavior than is generally thought. We used a physical 'doll' model and computer simulation to illustrate the point. (5) Twisting: Some gymnastic maneuvers require twisting. We are studying how to couple the biomechanics of the system to its control to produce efficient, stable twisting maneuvers.

  7. Locomotion in simulated microgravity: gravity replacement loads

    NASA Technical Reports Server (NTRS)

    McCrory, Jean L.; Baron, Heidi A.; Balkin, Sandy; Cavanagh, Peter R.

    2002-01-01

    BACKGROUND: When an astronaut walks or runs on a treadmill in microgravity, a subject load device (SLD) is used to return him or her back to the treadmill belt. The gravity replacement load (GRL) in the SLD is transferred, via a harness, to the pelvis and/or the shoulders. This research compared comfort and ground reaction forces during treadmill running in a microgravity locomotion simulator at GRLs of 60%, 80%, and 100% of body weight (BW). Two harness designs (shoulder springs only (SSO) and waist and shoulder springs (WSS)) were used. HYPOTHESES: 1) The 100% BW gravity replacement load conditions would be comfortably tolerated and would result in larger ground reaction forces and loading rates than the lower load conditions, and 2) the WSS harness would be more comfortable than the SSO harness. METHODS: Using the Penn State Zero Gravity Locomotion Simulator (ZLS), 8 subjects ran at 2.0 m x s(-1) (4.5 mph) for 3 min at each GRL setting in each harness. Subjective ratings of harness comfort, ground reaction forces, and GRL data were collected during the final minute of exercise. RESULTS: The 100% BW loading conditions were comfortably tolerated (2.3 on a scale of 0-10), although discomfort increased as the GRL increased. There were no overall differences in perceived comfort between the two harnesses. The loading rates (27.1, 33.8, 39.1 BW x s(-1)) and the magnitudes of the first (1.0, 1.4, 1.6 BW) and second (1.3, 1.7, 1.9 BW) peaks of the ground reaction force increased with increasing levels (60, 80, 100% BW respectively) of GRL. CONCLUSIONS: Subjects were able to tolerate a GRL of 100% BW well. The magnitude of the ground reaction force peaks and the loading rate is directly related to the magnitude of the GRL.

  8. 49 CFR 229.14 - Non-MU control cab locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Non-MU control cab locomotives. 229.14 Section 229... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS General § 229.14 Non-MU control cab locomotives. On each non-MU control cab locomotive, only those components added to the...

  9. 49 CFR 229.14 - Non-MU control cab locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Non-MU control cab locomotives. 229.14 Section 229... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS General § 229.14 Non-MU control cab locomotives. On each non-MU control cab locomotive, only those components added to the...

  10. 49 CFR 229.14 - Non-MU control cab locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Non-MU control cab locomotives. 229.14 Section 229... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS General § 229.14 Non-MU control cab locomotives. On each non-MU control cab locomotive, only those components added to the...

  11. 49 CFR 229.14 - Non-MU control cab locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Non-MU control cab locomotives. 229.14 Section 229... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS General § 229.14 Non-MU control cab locomotives. On each non-MU control cab locomotive, only those components added to the...

  12. 49 CFR 229.14 - Non-MU control cab locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Non-MU control cab locomotives. 229.14 Section 229... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS General § 229.14 Non-MU control cab locomotives. On each non-MU control cab locomotive, only those components added to the...

  13. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  14. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  15. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  16. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  17. 49 CFR 230.108 - Steam locomotive leading and trailing trucks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Steam locomotive leading and trailing trucks. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS Steam Locomotives and Tenders Trucks, Frames and Equalizing System § 230.108 Steam locomotive...

  18. A study to explore locomotion patterns in partial gravity environments

    NASA Technical Reports Server (NTRS)

    Rajulu, Sudhakar L.; Klute, Glenn K.; Moore, Nathan R.

    1992-01-01

    An effort is made to ascertain the factors affecting stability during locomotion in lunar and Martian gravity environments, as well as to establish criteria for the enhancement of stability and traction. The effects of changing both the speed and the pattern of locomotion under three different gravity conditions were investigated. As gravity level increased, vertical and horizontal forces significantly declined; similarities were noted across gravity levels, however, with respect to locomotion speed and pattern changes, where increasing speed enhanced both vertical and horizontal forces. With decreasing gravity, the ratio of horizontal to vertical forces increased significantly.

  19. [Evaluating influence of Captopril therapy on occupational activity of engine operators with hypertension].

    PubMed

    Serikov, V V; Kolyagin, V Ya; Bogdanova, V E

    2016-01-01

    The article covers results of study concerning influence of Captopril (25 mg) therapy on occupational activity of locomotive crew workers in real night travels model on training complex "EP1M locomotive operator cabin". Findings are that single use of Captopril (25 mg) in modelled railway activity enabled to increase reliability of occupational activity, that manifested in lower number of errors in locomotive operators' actions at night, and in psychophysiologic regulation of various psychic acts.

  20. Introduction to Focus Issue: Bipedal Locomotion-From Robots to Humans

    NASA Astrophysics Data System (ADS)

    Milton, John G.

    2009-06-01

    Running and walking, collectively referred to as bipedal locomotion, represent self-organized behaviors generated by a spatially distributed dynamical system operating under the constraint that a person must be able to move without falling down. The organizing principles involve both forces actively regulated by the nervous system and those generated passively by the biomechanical properties of the musculoskeletal system and the environment in which the movements occur. With the development of modern motion capture and electrophysiological techniques it has become possible to explore the dynamical interplay between the passive and active controllers of locomotion in a manner that directly compares observation to predictions made by relevant mathematical and computer models. Consequently, many of the techniques initially developed to study nonlinear dynamical systems, including stability analyses, phase resetting and entrainment properties of limit cycles, and fractal and multifractal analysis, have come to play major roles in guiding progress. This Focus Issue discusses bipedal locomotion from the point of view of dynamical systems theory with the goal of stimulating discussion between the dynamical systems, physics, biomechanics, and neuroscience communities.

  1. Caterpillar locomotion-inspired valveless pneumatic micropump using a single teardrop-shaped elastomeric membrane.

    PubMed

    So, Hongyun; Pisano, Albert P; Seo, Young Ho

    2014-07-07

    This paper presents a microfluidic pump operated by an asymmetrically deformed membrane, which was inspired by caterpillar locomotion. Almost all mechanical micropumps consist of two major components of fluid halting and fluid pushing parts, whereas the proposed caterpillar locomotion-inspired micropump has only a single, bilaterally symmetric membrane-like teardrop shape. A teardrop-shaped elastomeric membrane was asymmetrically deformed and then consecutively touched down to the bottom of the chamber in response to pneumatic pressure, thus achieving fluid pushing. Consecutive touchdown motions of the teardrop-shaped membrane mimicked the propagation of a caterpillar's hump during its locomotory gait. The initial touchdown motion of the teardrop-shaped membrane at the centroid worked as a valve that blocked the inlet channel, and then, the consecutive touchdown motions pushed fluid in the chamber toward the tail of the chamber connected to the outlet channel. The propagation of the touchdown motion of the teardrop-shaped membrane was investigated using computational analysis as well as experimental studies. This caterpillar locomotion-inspired micropump composed of only a single membrane can provide new opportunities for simple integration of microfluidic systems.

  2. Performance evaluation of the hydrogen-powered prototype locomotive 'Hydrogen Pioneer'

    NASA Astrophysics Data System (ADS)

    Hoffrichter, Andreas; Fisher, Peter; Tutcher, Jonathan; Hillmansen, Stuart; Roberts, Clive

    2014-03-01

    The narrow-gauge locomotive 'Hydrogen Pioneer', which was developed and constructed at the University of Birmingham, was employed to establish the performance of a hydrogen-hybrid railway traction vehicle. To achieve this several empirical tests were conducted. The locomotive utilises hydrogen gas in a Proton Exchange Membrane Fuel Cell power-plant to supply electricity to the traction motors or charge the on-board lead-acid batteries. First, the resistance to motion of the vehicle was determined, then operating tests were conducted for the speeds 2 km h-1, 6 km h-1, 7 km h-1, and 10 km h-1 on a 30 m straight, level alignment resembling light running. The power-plant and vehicle efficiency as well as the performance of the hybrid system were recorded. The observed overall duty cycle efficiency of the power-plant was from 28% to 40% and peak-power demand, such as during acceleration, was provided by the battery-pack, while average power during the duty cycle was met by the fuel cell stack, as designed. The tests establish the proof-of-concept for a hydrogen-hybrid railway traction vehicle and the results indicate that the traction system can be applied to full-scale locomotives.

  3. A bioinspired autonomous swimming robot as a tool for studying goal-directed locomotion.

    PubMed

    Manfredi, L; Assaf, T; Mintchev, S; Marrazza, S; Capantini, L; Orofino, S; Ascari, L; Grillner, S; Wallén, P; Ekeberg, O; Stefanini, C; Dario, P

    2013-10-01

    The bioinspired approach has been key in combining the disciplines of robotics with neuroscience in an effective and promising fashion. Indeed, certain aspects in the field of neuroscience, such as goal-directed locomotion and behaviour selection, can be validated through robotic artefacts. In particular, swimming is a functionally important behaviour where neuromuscular structures, neural control architecture and operation can be replicated artificially following models from biology and neuroscience. In this article, we present a biomimetic system inspired by the lamprey, an early vertebrate that locomotes using anguilliform swimming. The artefact possesses extra- and proprioceptive sensory receptors, muscle-like actuation, distributed embedded control and a vision system. Experiments on optimised swimming and on goal-directed locomotion are reported, as well as the assessment of the performance of the system, which shows high energy efficiency and adaptive behaviour. While the focus is on providing a robotic platform for testing biological models, the reported system can also be of major relevance for the development of engineering system applications.

  4. 49 CFR 229.315 - Operations and maintenance manual.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Operations and maintenance manual. 229.315 Section 229.315 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Electronics §...

  5. 49 CFR 229.319 - Operating Personnel Training.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Operating Personnel Training. 229.319 Section 229.319 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Electronics §...

  6. 49 CFR 229.319 - Operating Personnel Training.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Operating Personnel Training. 229.319 Section 229.319 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Electronics §...

  7. 49 CFR 229.315 - Operations and maintenance manual.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Operations and maintenance manual. 229.315 Section 229.315 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Electronics §...

  8. 49 CFR 229.319 - Operating Personnel Training.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Operating Personnel Training. 229.319 Section 229.319 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Electronics §...

  9. 49 CFR 229.315 - Operations and maintenance manual.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Operations and maintenance manual. 229.315 Section 229.315 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD LOCOMOTIVE SAFETY STANDARDS Locomotive Electronics §...

  10. 10. Locomotive smoke flue coming through Roundhouse roof with gable ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. Locomotive smoke flue coming through Roundhouse roof with gable end of Machine Shop in background. - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Roundhouse, Site Bounded by West Broad, Jones, West Boundary & Hull, Savannah, Chatham County, GA

  11. EXTERIOR VIEW WITH HEART OF DIXIE MUSEUM'S HISTORIC LOCOMOTIVE IN ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    EXTERIOR VIEW WITH HEART OF DIXIE MUSEUM'S HISTORIC LOCOMOTIVE IN MUSEUM'S POWELL AVENUE YARD (BOTTOM) AND SOUTHERN RAILWAY BOXCAR ON ACTIVE TRACKAGE (ABOVE). - Heart of Dixie Railroad, Rolling Stock, 1800 Block Powell Avenue, Birmingham, Jefferson County, AL

  12. "Shower head" water connection for servicing railroad locomotives, perspective view ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    "Shower head" water connection for servicing railroad locomotives, perspective view looking NW across ATSF railyard. - Grand Canyon Village Utilities, Grand Canyon National Park, Grand Canyon Village, Coconino County, AZ

  13. TURNTABLE, WITH ATSF 5021, UNRESTORED 2104 STEAM LOCOMOTIVE, LOOKING EAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    TURNTABLE, WITH ATSF 5021, UNRESTORED 2-10-4 STEAM LOCOMOTIVE, LOOKING EAST. CAR MACHINE SHOP IS IN BACKGROUND AND ERECTING/MACHINE SHOP IS AT RIGHT. - Southern Pacific, Sacramento Shops, Turntable, 111 I Street, Sacramento, Sacramento County, CA

  14. Breathing and locomotion: comparative anatomy, morphology and function.

    PubMed

    Klein, Wilfried; Codd, Jonathan R

    2010-08-31

    Using specialized respiratory structures such as gills, lungs and or a tracheal system, animals take up oxygen and release carbon dioxide. The efficiency of gas exchange, however, may be constrained by the morphology of the respiratory organ itself as well as by other aspects of an animal's physiology such as feeding, circulation or locomotion. Herein we discuss some aspects of the functional link between the respiratory and locomotor systems, such as gill morphology of sharks as a factor limiting maximum aerobic scope, respiratory constraints among legless lizards, lung morphology of testudines, trade-offs between locomotion and respiration among birds, reconstruction of the respiratory system of sauropods, respiration of mice during locomotion as well as some aspects of gas exchange among insects. Data covering such a broad spectrum of interactions between the locomotor and respiratory systems shall allow us to place breathing and locomotion into a wider context of evolution of oxygen.

  15. EXTERIOR VIEW WITH HISTORIC LOCOMOTIVES, COAL AND PASSENGER CARS INCLUDING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    EXTERIOR VIEW WITH HISTORIC LOCOMOTIVES, COAL AND PASSENGER CARS INCLUDING THE WOODWARD IRON COMPANY NO. 38 LOCOMOTIVE AND TENDER LOCATED IN THE HEART OF DIXIE MUSEUM'S POWELL AVENUE YARD AND SOUTHERN RAILROAD BOXCARS ON ACTIVE TRACKS OF BIRMINGHAM'S RAILROAD RESERVATION. IN BACKGROUND AT RIGHT AND CENTER IS THE BIRMINGHAM CITY CENTER. - Heart of Dixie Railroad, Rolling Stock, 1800 Block Powell Avenue, Birmingham, Jefferson County, AL

  16. Locomotion in Lymphocytes is Altered by Differential PKC Isoform Expression

    NASA Technical Reports Server (NTRS)

    Sundaresan, A.; Risin, D.; Pellis, N. R.

    1999-01-01

    Lymphocyte locomotion is critical for proper elicitation of the immune response. Locomotion of immune cells via the interstitium is essential for optimal immune function during wound healing, inflammation and infection. There are conditions which alter lymphocyte locomotion and one of them is spaceflight. Lymphocyte locomotion is severely inhibited in true spaceflight (true microgravity) and in rotating wall vessel culture (modeled microgravity). When lymphocytes are activated prior to culture in modeled microgravity, locomotion is not inhibited and the levels are comparable to those of static cultured lymphocytes. When a phorbol ester (PMA) is used in modeled microgravity, lymphocyte locomotion is restored by 87%. This occurs regardless if PMA is added after culture in the rotating wall vessel or during culture. Inhibition of DNA synthesis also does not alter restoration of lymphocyte locomotion by PMA. PMA is a direct activator of (protein kinase C) PKC . When a calcium ionophore, ionomycin is used it does not possess any restorative properties towards locomotion either alone or collectively with PMA. Since PMA brings about restoration without help from calcium ionophores (ionomycin), it is infer-red that calcium independent PKC isoforms are involved. Changes were perceived in the protein levels of PKC 6 where levels of the protein were downregulated at 24,72 and 96 hours in untreated rotated cultures (modeled microgravity) compared to untreated static (1g) cultures. At 48 hours there is an increase in the levels of PKC & in the same experimental set up. Studies on transcriptional and translational patterns of calcium independent isoforms of PKC such as 8 and E are presented in this study.

  17. The Geometry of Locomotive Behavioral States in C. elegans

    PubMed Central

    Bjorness, Theresa; Greene, Robert; You, Young-Jai

    2013-01-01

    We develop a new hidden Markov model-based method to analyze C elegans locomotive behavior and use this method to quantitatively characterize behavioral states. In agreement with previous work, we find states corresponding to roaming, dwelling, and quiescence. However, we also find evidence for a continuum of intermediate states. We suggest that roaming, dwelling, and quiescence may best be thought of as extremes which, mixed in any proportion, define the locomotive repertoire of C elegans foraging and feeding behavior. PMID:23555813

  18. Serotonin Influences Locomotion in the Nudibranch Mollusc Melibe leonina

    PubMed Central

    LEWIS, STEFANIE L.; LYONS, DEBORAH E.; MEEKINS, TIFFANIE L.; NEWCOMB, JAMES M.

    2015-01-01

    Serotonin (5-HT) influences locomotion in many animals, from flatworms to mammals. This study examined the effects of 5-HT on locomotion in the nudibranch mollusc Melibe leonina (Gould, 1852). M. leonina exhibits two modes of locomotion, crawling and swimming. Animals were bath-immersed in a range of concentrations of 5-HT or injected with various 5-HT solutions into the hemolymph and then monitored for locomotor activity. In contrast to other gastropods studied, M. leonina showed no significant effect of 5-HT on the distance crawled or the speed of crawling. However, the highest concentration (10−3 mol l−1 for bath immersion and 10−5 mol l−1 for injection) significantly increased the time spent swimming and the swimming speed. The 5-HT receptor antagonist methysergide inhibited the influence of 5-HT on the overall amount of swimming but not on swimming speed. These results suggest that 5-HT influences locomotion at the behavioral level in M. leonina. In conjunction with previous studies on the neural basis of locomotion in M. leonina, these results also suggest that this species is an excellent model system for investigating the 5-HT modulation of locomotion. PMID:21712224

  19. The coupling of vision with locomotion in cortical blindness.

    PubMed

    Pelah, Adar; Barbur, John; Thurrell, Adrian; Hock, Howard S

    2015-05-01

    Maintaining or modifying the speed and direction of locomotion requires the coupling of the locomotion with the retinal optic flow that it generates. It is shown that this essential behavioral capability, which requires on-line neural control, is preserved in the cortically blind hemifield of a hemianope. In experiments, optic flow stimuli were presented to either the normal or blind hemifield while the patient was walking on a treadmill. Little difference was found between the hemifields with respect to the coupling (i.e. co-dependency) of optic flow detection with locomotion. Even in the cortically blind hemifield, faster walking resulted in the perceptual slowing of detected optic flow, and self-selected locomotion speeds demonstrated behavioral discrimination between different optic flow speeds. The results indicate that the processing of optic flow, and thereby on-line visuo-locomotor coupling, can take place along neural pathways that function without processing in Area V1, and thus in the absence of conscious intervention. These and earlier findings suggest that optic flow and object motion are processed in parallel along with correlated non-visual locomotion signals. Extrastriate interactions may be responsible for discounting the optical effects of locomotion on the perceived direction of object motion, and maintaining visually guided self-motion.

  20. A subset of interneurons required for Drosophila larval locomotion

    PubMed Central

    Yoshikawa, Shingo; Long, Hong; Thomas, John B.

    2015-01-01

    Efforts to define the neural circuits generating locomotor behavior have produced an initial understanding of some of the components within the spinal cord, as well as a basic understanding of several invertebrate motor pattern generators. However, how these circuits are assembled during development is poorly understood. We are defining the neural circuit that generates larval locomotion in the genetically tractable fruit fly Drosophila melanogaster to study locomotor circuit development. Forward larval locomotion involves a stereotyped posterior-to-anterior segmental translocation of body wall muscle contraction and is generated by a relatively small number of identified muscles, motor and sensory neurons, plus an unknown number of the ~270 bilaterally-paired interneurons per segment of the 1st instar larva. To begin identifying the relevant interneurons, we have conditionally inactivated synaptic transmission of interneuron subsets and assayed for the effects on locomotion. From this screen we have identified a subset of 25 interneurons per hemisegment, called the lateral locomotor neurons (LLNs), that are required for locomotion. Both inactivation and constitutive activation of the LLNs disrupt locomotion, indicating that patterned output of the LLNs is required. By expressing a calcium indicator in the LLNs, we found that they display a posterior-to-anterior wave of activity within the CNS corresponding to the segmental translocation of the muscle contraction wave. Identification of the LLNs represents the first step toward elucidating the circuit generating larval locomotion. PMID:26621406

  1. Visuomotor Control of Human Adaptive Locomotion: Understanding the Anticipatory Nature

    PubMed Central

    Higuchi, Takahiro

    2013-01-01

    To maintain balance during locomotion, the central nervous system (CNS) accommodates changes in the constraints of spatial environment (e.g., existence of an obstacle or changes in the surface properties). Locomotion while modifying the basic movement patterns in response to such constraints is referred to as adaptive locomotion. The most powerful means of ensuring balance during adaptive locomotion is to visually perceive the environmental properties at a distance and modify the movement patterns in an anticipatory manner to avoid perturbation altogether. For this reason, visuomotor control of adaptive locomotion is characterized, at least in part, by its anticipatory nature. The purpose of the present article is to review the relevant studies which revealed the anticipatory nature of the visuomotor control of adaptive locomotion. The anticipatory locomotor adjustments for stationary and changeable environment, as well as the spatio-temporal patterns of gaze behavior to support the anticipatory locomotor adjustments are described. Such description will clearly show that anticipatory locomotor adjustments are initiated when an object of interest (e.g., a goal or obstacle) still exists in far space. This review also show that, as a prerequisite of anticipatory locomotor adjustments, environmental properties are accurately perceived from a distance in relation to individual’s action capabilities. PMID:23720647

  2. How animals move: comparative lessons on animal locomotion.

    PubMed

    Schaeffer, Paul J; Lindstedt, Stan L

    2013-01-01

    Comparative physiology often provides unique insights in animal structure and function. It is specifically through this lens that we discuss the fundamental properties of skeletal muscle and animal locomotion, incorporating variation in body size and evolved difference among species. For example, muscle frequencies in vivo are highly constrained by body size, which apparently tunes muscle use to maximize recovery of elastic recoil potential energy. Secondary to this constraint, there is an expected linking of skeletal muscle structural and functional properties. Muscle is relatively simple structurally, but by changing proportions of the few muscle components, a diverse range of functional outputs is possible. Thus, there is a consistent and predictable relation between muscle function and myocyte composition that illuminates animal locomotion. When animals move, the mechanical properties of muscle diverge from the static textbook force-velocity relations described by A. V. Hill, as recovery of elastic potential energy together with force and power enhancement with activation during stretch combine to modulate performance. These relations are best understood through the tool of work loops. Also, when animals move, locomotion is often conveniently categorized energetically. Burst locomotion is typified by high-power outputs and short durations while sustained, cyclic, locomotion engages a smaller fraction of the muscle tissue, yielding lower force and power. However, closer examination reveals that rather than a dichotomy, energetics of locomotion is a continuum. There is a remarkably predictable relationship between duration of activity and peak sustainable performance.

  3. A subset of interneurons required for Drosophila larval locomotion.

    PubMed

    Yoshikawa, Shingo; Long, Hong; Thomas, John B

    2016-01-01

    Efforts to define the neural circuits generating locomotor behavior have produced an initial understanding of some of the components within the spinal cord, as well as a basic understanding of several invertebrate motor pattern generators. However, how these circuits are assembled during development is poorly understood. We are defining the neural circuit that generates larval locomotion in the genetically tractable fruit fly Drosophila melanogaster to study locomotor circuit development. Forward larval locomotion involves a stereotyped posterior-to-anterior segmental translocation of body wall muscle contraction and is generated by a relatively small number of identified muscles, motor and sensory neurons, plus an unknown number of the ~270 bilaterally-paired interneurons per segment of the 1st instar larva. To begin identifying the relevant interneurons, we have conditionally inactivated synaptic transmission of interneuron subsets and assayed for the effects on locomotion. From this screen we have identified a subset of 25 interneurons per hemisegment, called the lateral locomotor neurons (LLNs), that are required for locomotion. Both inactivation and constitutive activation of the LLNs disrupt locomotion, indicating that patterned output of the LLNs is required. By expressing a calcium indicator in the LLNs, we found that they display a posterior-to-anterior wave of activity within the CNS corresponding to the segmental translocation of the muscle contraction wave. Identification of the LLNs represents the first step toward elucidating the circuit generating larval locomotion.

  4. Intramuscular Pressure Measurement During Locomotion in Humans

    NASA Technical Reports Server (NTRS)

    Ballard, Ricard E.

    1996-01-01

    To assess the usefulness of intramuscular pressure (IMP) measurement for studying muscle function during gait, IMP was recorded in the soleus and tibialis anterior muscles of ten volunteers during, treadmill walking, and running using transducer-tipped catheters. Soleus IMP exhibited single peaks during late-stance phase of walking (181 +/- 69 mmHg, mean +/- S.E.) and running (269 +/- 95 mmHg). Tibialis anterior IMP showed a biphasic response, with the largest peak (90 +/- 15 mmHg during walking and 151 +/- 25 mmHg during running) occurring shortly after heel strike. IMP magnitude increased with gait speed in both muscles. Linear regression of soleus IMP against ankle joint torque obtained by a dynamometer in two subjects produced linear relationships (r = 0.97). Application of these relationships to IMP data yielded estimated peak soleus moment contributions of 0.95-165 Nm/Kg during walking, and 1.43-2.70 Nm/Kg during running. IMP results from local muscle tissue deformations caused by muscle force development and thus, provides a direct, practical index of muscle function during locomotion in humans.

  5. Water surface locomotion in tropical canopy ants.

    PubMed

    Yanoviak, S P; Frederick, D N

    2014-06-15

    Upon falling onto the water surface, most terrestrial arthropods helplessly struggle and are quickly eaten by aquatic predators. Exceptions to this outcome mostly occur among riparian taxa that escape by walking or swimming at the water surface. Here we document sustained, directional, neustonic locomotion (i.e. surface swimming) in tropical arboreal ants. We dropped 35 species of ants into natural and artificial aquatic settings in Peru and Panama to assess their swimming ability. Ten species showed directed surface swimming at speeds >3 body lengths s(-1), with some swimming at absolute speeds >10 cm s(-1). Ten other species exhibited partial swimming ability characterized by relatively slow but directed movement. The remaining species showed no locomotory control at the surface. The phylogenetic distribution of swimming among ant genera indicates parallel evolution and a trend toward negative association with directed aerial descent behavior. Experiments with workers of Odontomachus bauri showed that they escape from the water by directing their swimming toward dark emergent objects (i.e. skototaxis). Analyses of high-speed video images indicate that Pachycondyla spp. and O. bauri use a modified alternating tripod gait when swimming; they generate thrust at the water surface via synchronized treading and rowing motions of the contralateral fore and mid legs, respectively, while the hind legs provide roll stability. These results expand the list of facultatively neustonic terrestrial taxa to include various species of tropical arboreal ants.

  6. Vestibular compensation and orientation during locomotion

    NASA Technical Reports Server (NTRS)

    Raphan, T.; Imai, T.; Moore, S. T.; Cohen, B.

    2001-01-01

    Body, head, and eye movements were studied in three dimensions while walking and turning to determine the role of the vestibular system in directing gaze and maintaining spatial orientation. The body, head, and eyes were represented as three-dimensional coordinate frames, and the movement of these frames was related to a trajectory frame that described the motion of the body on a terrestrial plane. The axis-angle of the body, head, and eye rotation were then compared to the axis-angle of the rotation of the gravitoinertial acceleration (GIA). We inferred the role of the vestibular system during locomotion and the contributions of the VCR and VOR by examining the interrelationship between these coordinate frames. Straight walking induced head and eye rotations in a compensatory manner to the linear accelerations, maintaining head pointing and gaze along the direction of forward motion. Turning generated a combination of compensation and orientation responses. The head leads and steers the turn while the eyes compensate to maintain stable horizontal gaze in space. Saccades shift horizontal gaze as the turn is executed. The head pitches, as during straight walking. It also rolls so that the head tends to align with the orientation of the GIA. Head orientation changes anticipate orientation changes of the GIA. Eye orientation follows the changes in GIA orientation so that the net orientation gaze is closer to the orientation of the GIA. The study indicates that the vestibular system utilizes compensatory and orienting mechanisms to stabilize spatial orientation and gaze during walking and turning.

  7. Legged-locomotion on inclined granular media

    NASA Astrophysics Data System (ADS)

    Rieser, Jennifer; Qian, Feifei; Goldman, Daniel

    Animals traverse a wide variety of complex environments, including situations in which the ground beneath them can yield (e.g. dry granular media in desert dunes). Locomotion strategies that are effective on level granular media can fail when traversing a granular slope. Taking inspiration from successful legged-locomotors in sandy, uneven settings, we explore the ability of a small (15 cm long, 100 g), six-c-shaped legged robot to run uphill in a bed of 1-mm-diameter poppy seeds, using an alternating tripod gait. Our fully automated experiments reveal that locomotor performance can depend sensitively on both environmental parameters such as the inclination angle and volume fraction of the substrate, and robot morphology and control parameters like leg shape, step frequency, and the friction between the feet of the robot and the substrate. We assess performance by measuring the average speed of the robot, and we find that the robot tends to perform better at higher step frequency and lower inclination angles, and that average speed decreases more rapidly with increasing angle for higher step frequency.

  8. Stokesian locomotion in elastic fluids: Experiments

    NASA Astrophysics Data System (ADS)

    Zenit, Roberto; Lauga, Eric

    2010-11-01

    In many instances of biological relevance, self-propelled cells have to swim through non-Newtonian fluids. In order to provide fundamental understanding on the effect of such non-Newtonian stresses on locomotion, we have studied the motion an oscillating magnetic swimmer immersed in both Newtonian and non-Newtonian liquids at small Reynolds numbers. The swimmer is made with a small rare earth (Neodymium-Iron-Boron) magnetic rod (3 mm) to which a flexible tail was glued. This array was immersed in cylindrical container (50 mm diameter) in which the test fluid was contained. A nearly uniform oscillating magnetic field was created with a Helmholtz coil (R=200mm) and a AC power supply. For the Newtonian case, a 30,000 cSt silicon oil was used. In the non-Newtonian case, a fluid with nearly constant viscosity and large first normal stress difference (highly elastic) was used; this fluid was made with Corn syrup with a small amount of polyacrylamide. The swimming speed was measured, for different amplitudes and frequencies, using a digital image analysis. The objective of the present investigation is to determine whether the elastic effects of the fluid improve or not the swimming performance. Some preliminary results will be presented and discussed.

  9. Spinal cord pattern generators for locomotion.

    PubMed

    Dietz, V

    2003-08-01

    It is generally accepted that locomotion in mammals, including humans, is based on the activity of neuronal circuits within the spinal cord (the central pattern generator, CPG). Afferent information from the periphery (i.e. the limbs) influences the central pattern and, conversely, the CPG selects appropriate afferent information according to the external requirement. Both the CPG and the reflexes that mediate afferent input to the spinal cord are under the control of the brainstem. There is increasing evidence that in central motor diseases, a defective utilization of afferent input, in combination with secondary compensatory processes, is involved in typical movement disorders, such as spasticity and Parkinson's disease. Recent studies indicate a plastic behavior of the spinal neuronal circuits following a central motor lesion. This has implications for any rehabilitative therapy that should be directed to take advantage of the plasticity of the central nervous system. The significance of this research is in a better understanding of the pathophysiology underlying movement disorders and the consequences for an appropriate treatment.

  10. Incidental sounds of locomotion in animal cognition.

    PubMed

    Larsson, Matz

    2012-01-01

    The highly synchronized formations that characterize schooling in fish and the flight of certain bird groups have frequently been explained as reducing energy expenditure. I present an alternative, or complimentary, hypothesis that synchronization of group movements may improve hearing perception. Although incidental sounds produced as a by-product of locomotion (ISOL) will be an almost constant presence to most animals, the impact on perception and cognition has been little discussed. A consequence of ISOL may be masking of critical sound signals in the surroundings. Birds in flight may generate significant noise; some produce wing beats that are readily heard on the ground at some distance from the source. Synchronization of group movements might reduce auditory masking through periods of relative silence and facilitate auditory grouping processes. Respiratory locomotor coupling and intermittent flight may be other means of reducing masking and improving hearing perception. A distinct border between ISOL and communicative signals is difficult to delineate. ISOL seems to be used by schooling fish as an aid to staying in formation and avoiding collisions. Bird and bat flocks may use ISOL in an analogous way. ISOL and interaction with animal perception, cognition, and synchronized behavior provide an interesting area for future study.

  11. Leg intramuscular pressures during locomotion in humans

    NASA Technical Reports Server (NTRS)

    Ballard, R. E.; Watenpaugh, D. E.; Breit, G. A.; Murthy, G.; Holley, D. C.; Hargens, A. R.

    1998-01-01

    To assess the usefulness of intramuscular pressure (IMP) measurement for studying muscle function during gait, IMP was recorded in the soleus and tibialis anterior muscles of 10 volunteers during treadmill walking and running by using transducer-tipped catheters. Soleus IMP exhibited single peaks during late-stance phase of walking [181 +/- 69 (SE) mmHg] and running (269 +/- 95 mmHg). Tibialis anterior IMP showed a biphasic response, with the largest peak (90 +/- 15 mmHg during walking and 151 +/- 25 mmHg during running) occurring shortly after heel strike. IMP magnitude increased with gait speed in both muscles. Linear regression of soleus IMP against ankle joint torque obtained by a dynamometer produced linear relationships (n = 2, r = 0.97 for both). Application of these relationships to IMP data yielded estimated peak soleus moment contributions of 0.95-1.65 N . m/kg during walking, and 1.43-2.70 N . m/kg during running. Phasic elevations of IMP during exercise are probably generated by local muscle tissue deformations due to muscle force development. Thus profiles of IMP provide a direct, reproducible index of muscle function during locomotion in humans.

  12. Nematode locomotion in unconfined and confined fluids

    NASA Astrophysics Data System (ADS)

    Bilbao, Alejandro; Wajnryb, Eligiusz; Vanapalli, Siva A.; Blawzdziewicz, Jerzy

    2013-08-01

    The millimeter-long soil-dwelling nematode Caenorhabditis elegans propels itself by producing undulations that propagate along its body and turns by assuming highly curved shapes. According to our recent study [V. Padmanabhan et al., PLoS ONE 7, e40121 (2012), 10.1371/journal.pone.0040121] all these postures can be accurately described by a piecewise-harmonic-curvature model. We combine this curvature-based description with highly accurate hydrodynamic bead models to evaluate the normalized velocity and turning angles for a worm swimming in an unconfined fluid and in a parallel-wall cell. We find that the worm moves twice as fast and navigates more effectively under a strong confinement, due to the large transverse-to-longitudinal resistance-coefficient ratio resulting from the wall-mediated far-field hydrodynamic coupling between body segments. We also note that the optimal swimming gait is similar to the gait observed for nematodes swimming in high-viscosity fluids. Our bead models allow us to determine the effects of confinement and finite thickness of the body of the nematode on its locomotion. These effects are not accounted for by the classical resistive-force and slender-body theories.

  13. Stability versus maneuverability in aquatic locomotion.

    PubMed

    Weihs, Daniel

    2002-02-01

    The dictionary definition of stability as "Firmly established, not easily to be changed" immediately indicates the conflict between stability and maneuverability in aquatic locomotion. The present paper addresses several issues resulting from these opposing requirements. Classical stability theory for bodies moving in fluids is based on developments in submarine and airship motions. These have lateral symmetry, in common with most animals. This enables the separation of the equations of motion into two sets of 3 each. The vertical (longitudinal) set, which includes motions in the axial (surge), normal (heave) and pitching directions, can thus be separated from the lateral-horizontal plane which includes yaw, roll and sideslip motions. This has been found useful in the past for longitudinal stability studies based on coasting configurations but is not applicable to the analysis of turning, fast starts and vigorous swimming, where the lateral symmetry of the fish body is broken by bending motions. The present paper will also examine some of the aspects of the stability vs. maneuverability tradeoff for these asymmetric motions. An analysis of the conditions under which the separation of equations of motions into vertical and horizontal planes is justified, and a definition of the equations to be used in cases where this separation is not accurate enough is presented.

  14. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  15. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  16. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  17. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  18. 40 CFR 201.27 - Procedures for: (1) Determining applicability of the locomotive load cell test stand standard and...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... applicability of the locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a receiving property; (2) measurement of locomotive load cell test stands more than 120 meters... locomotive load cell test stand standard and switcher locomotive standard by noise measurement on a...

  19. Regulated and non-regulated emissions from in-use diesel-electric switching locomotives.

    PubMed

    Sawant, Aniket A; Nigam, Abhilash; Miller, J Wayne; Johnson, Kent C; Cocker, David R

    2007-09-01

    Diesel-electric locomotives are vital to the operation of freight railroads in the United States, and emissions from this source category have generated interest in recent years. They are also gaining attention as an important emission source under the larger set of nonroad sources, both from a regulated emissions and health effects standpoint. The present work analyzes regulated (NOx, PM, THC, CO) and non-regulated emissions from three in-use diesel-electric switching locomotives using standardized sampling and analytical techniques. The engines tested in this work were from 1950, 1960, and 1970 and showed a range of NOx and PM emissions. In general, non-regulated gaseous emissions showed a sharp increase as engines shifted from non-idle to idle operating modes. This is interesting from an emissions perspective since activity data shows that these locomotives spend around 60% of their time idling. In terms of polycyclicaromatic hydrocarbon (PAH) contributions, the dominance of naphthalene and its derivatives over the total PAH emissions was apparent, similar to observations for on-road diesel tractors. Among nonnaphthalenic species, itwas observed that lower molecular weight PAHs and n-alkanes dominated their respective compound classes. Regulated emissions from a newer technology engine used in a back-up generator (BUG) application were also compared againstthe present engines; it was determined that use of the newer engine may lower NOx and PM emissions by up to 30%. Another area of interest to regulators is better estimation of the marine engine inventory for port operations. Toward that end, a comparison of emissions from these engines with engine manufacturer data and the newer technology BUG engine was also performed for a marine duty cycle, another application where these engines are used typically with little modifications.

  20. 49 CFR 240.117 - Criteria for consideration of operating rules compliance data.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) of this section, with railroad rules and practices for the safe operation of trains shall not be... operation of trains shall have his or her certification revoked. (2) A Designated Supervisor of Locomotive... person who is a certified locomotive engineer but is called by a railroad to perform the duty of a...

  1. 49 CFR 240.117 - Criteria for consideration of operating rules compliance data.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) of this section, with railroad rules and practices for the safe operation of trains shall not be... operation of trains shall have his or her certification revoked. (2) A Designated Supervisor of Locomotive... person who is a certified locomotive engineer but is called by a railroad to perform the duty of a...

  2. Computer coordination of limb motion for locomotion of a multiple-armed robot for space assembly

    NASA Technical Reports Server (NTRS)

    Klein, C. A.; Patterson, M. R.

    1982-01-01

    Consideration is given to a possible robotic system for the construction of large space structures, which may be described as a multiple general purpose arm manipulator vehicle that can walk over the structure under construction to a given site for further work. A description is presented of the locomotion of such a vehicle, modeling its arms in terms of a currently available industrial manipulator. It is noted that for whatever maximum speed of operation is chosen, rapid changes in robot velocity create situations in which already-selected handholds are no longer practical. A step is added to the 'free gait' walking algorithm in order to solve this problem.

  3. Stabilization of cat paw trajectory during locomotion

    PubMed Central

    Klishko, Alexander N.; Farrell, Bradley J.; Beloozerova, Irina N.; Latash, Mark L.

    2014-01-01

    We investigated which of cat limb kinematic variables during swing of regular walking and accurate stepping along a horizontal ladder are stabilized by coordinated changes of limb segment angles. Three hypotheses were tested: 1) animals stabilize the entire swing trajectory of specific kinematic variables (performance variables); and 2) the level of trajectory stabilization is similar between regular and ladder walking and 3) is higher for forelimbs compared with hindlimbs. We used the framework of the uncontrolled manifold (UCM) hypothesis to quantify the structure of variance of limb kinematics in the limb segment orientation space across steps. Two components of variance were quantified for each potential performance variable, one of which affected it (“bad variance,” variance orthogonal to the UCM, VORT) while the other one did not (“good variance,” variance within the UCM, VUCM). The analysis of five candidate performance variables revealed that cats during both locomotor behaviors stabilize 1) paw vertical position during the entire swing (VUCM > VORT, except in mid-hindpaw swing of ladder walking) and 2) horizontal paw position in initial and terminal swing (except for the entire forepaw swing of regular walking). We also found that the limb length was typically stabilized in midswing, whereas limb orientation was not (VUCM ≤ VORT) for both limbs and behaviors during entire swing. We conclude that stabilization of paw position in early and terminal swing enables accurate and stable locomotion, while stabilization of vertical paw position in midswing helps paw clearance. This study is the first to demonstrate the applicability of the UCM-based analysis to nonhuman movement. PMID:24899676

  4. Vitamin D receptor signaling enhances locomotive ability in mice.

    PubMed

    Sakai, Sadaoki; Suzuki, Miho; Tashiro, Yoshihito; Tanaka, Keisuke; Takeda, Satoshi; Aizawa, Ken; Hirata, Michinori; Yogo, Kenji; Endo, Koichi

    2015-01-01

    Bone fractures markedly reduce quality of life and life expectancy in elderly people. Although osteoporosis increases bone fragility, fractures frequently occur in patients with normal bone mineral density. Because most fractures occur on falling, preventing falls is another focus for reducing bone fractures. In this study, we investigated the role of vitamin D receptor (VDR) signaling in locomotive ability. In the rotarod test, physical exercise enhanced locomotive ability of wild-type (WT) mice by 1.6-fold, whereas exercise did not enhance locomotive ability of VDR knockout (KO) mice. Compared with WT mice, VDR KO mice had smaller peripheral nerve axonal diameter and disordered AChR morphology on the extensor digitorum longus muscle. Eldecalcitol (ED-71, ELD), an analog of 1,25(OH)2 D3 , administered to rotarod-trained C57BL/6 mice enhanced locomotor performance compared with vehicle-treated nontrained mice. The area of AChR cluster on the extensor digitorum longus was greater in ELD-treated mice than in vehicle-treated mice. ELD and 1,25(OH)2 D3 enhanced expression of IGF-1, myelin basic protein, and VDR in rat primary Schwann cells. VDR signaling regulates neuromuscular maintenance and enhances locomotive ability after physical exercise. Further investigation is required, but Schwann cells and the neuromuscular junction are targets of vitamin D3 signaling in locomotive ability.

  5. Locomotion of neutrally buoyant fish with flexible caudal fin.

    PubMed

    Iosilevskii, Gil

    2016-06-21

    Historically, burst-and-coast locomotion strategies have been given two very different explanations. The first one was based on the assumption that the drag of an actively swimming fish is greater than the drag of the same fish in motionless glide. Fish reduce the cost of locomotion by swimming actively during a part of the swimming interval, and gliding through the remaining part. The second one was based on the assumption that muscles perform efficiently only if their contraction rate exceeds a certain threshold. Fish reduce the cost of locomotion by using an efficient contraction rate during a part of the swimming interval, and gliding through the remaining part. In this paper, we suggest yet a third explanation. It is based on the assumption that propulsion efficiency of a swimmer can increase with thrust. Fish reduce the cost of locomotion by alternating high thrust, and hence more efficient, bursts with passive glides. The paper presents a formal analysis of the respective burst-and-coast strategy, shows that the locomotion efficiency can be practically as high as the propulsion efficiency during burst, and shows that the other two explanations can be considered particular cases of the present one.

  6. Effect of relocation on locomotion and cleanliness in dairy cows.

    PubMed

    Wilkes, Crafton O; Pence, Kristen J; Hurt, Amanda M; Becvar, Ondrej; Knowlton, Katharine F; McGilliard, Michael L; Gwazdauskas, Francis C

    2008-02-01

    This study was conducted to determine the effect that relocation to a new free stall barn had on locomotion and cleanliness of two breeds of dairy cows. The original facility before relocation had cows housed in an 8-row free stall barn. Cows were allocated in a new 4-row free stall facility: cows of two breeds (n=22 Holsteins and 22 Jerseys) were intermixed in the northwest section. Locomotion (scale 1-5) and cleanliness were scored (scale 1-4). Holsteins and Jerseys had no difference in locomotion score throughout 12 weeks following relocation. A lactation number by date interaction showed cows in third and greater lactations had significantly higher locomotion scores (more lameness) by day 86. Locomotion scores increased across breeds during the 86-d observation period, suggesting cows became lamer. Jerseys had cleaner lower legs than Holsteins (2.9+/-0.1 v. 3.5+/-0.1, respectively). Lactation number affected lower leg cleanliness, with scores decreasing as lactation number increased (3.4 v. 3.3 v. 2.9+/-0.10 for first, second and third and greater lactations, respectively; P<0.01). All cows were cleaner (lower scores) after relocation, suggesting that the new facility improved hygiene.

  7. Noninvasive Multimodal Imaging to Predict Recovery of Locomotion after Extended Limb Ischemia.

    PubMed

    Radowsky, Jason S; Caruso, Joseph D; Luthra, Rajiv; Bradley, Matthew J; Elster, Eric A; Forsberg, Jonathan A; Crane, Nicole J

    2015-01-01

    Acute limb ischemia is a common cause of morbidity and mortality following trauma both in civilian centers and in combat related injuries. Rapid determination of tissue viability and surgical restoration of blood flow are desirable, but not always possible. We sought to characterize the response to increasing periods of hind limb ischemia in a porcine model such that we could define a period of critical ischemia (the point after which irreversible neuromuscular injury occurs), evaluate non-invasive methods for characterizing that ischemia, and establish a model by which we could predict whether or not the animal's locomotion would return to baselines levels post-operatively. Ischemia was induced by either application of a pneumatic tourniquet or vessel occlusion (performed by clamping the proximal iliac artery and vein at the level of the inguinal ligament). The limb was monitored for the duration of the procedure with both 3-charge coupled device (3CCD) and infrared (IR) imaging for tissue oxygenation and perfusion, respectively. The experimental arms of this model are effective at inducing histologically evident muscle injury with some evidence of expected secondary organ damage, particularly in animals with longer ischemia times. Noninvasive imaging data shows excellent correlation with post-operative functional outcomes, validating its use as a non-invasive means of viability assessment, and directly monitors post-occlusive reactive hyperemia. A classification model, based on partial-least squares discriminant analysis (PLSDA) of imaging variables only, successfully classified animals as "returned to normal locomotion" or "did not return to normal locomotion" with 87.5% sensitivity and 66.7% specificity after cross-validation. PLSDA models generated from non-imaging data were not as accurate (AUC of 0.53) compared the PLSDA model generated from only imaging data (AUC of 0.76). With some modification, this limb ischemia model could also serve as a means on which

  8. Effect of a fuel activation device (FAD) on particulate matter and black carbon emissions from a diesel locomotive engine.

    PubMed

    Park, Duckshin; Lee, Taejeong; Lee, Yongil; Jeong, Wonseog; Kwon, Soon-Bark; Kim, Dongsool; Lee, Kiyoung

    2017-01-01

    Emission reduction is one of the most efficient control measures in fuel-powered locomotives. The purpose of this study was to determine the reduction in particulate matter (PM) and black carbon (BC) emissions following the installation of a fuel activation device (FAD). The FAD was developed to enhance fuel combustion by atomizing fuel and to increase the surface area per unit volume of injected fuel. Emission reduction by the FAD was evaluated by installing a FAD in an operating diesel locomotive in Mongolia. The test was conducted on a train operating on a round-trip 238-km route between Ulaanbaatar and Choir stations in Mongolia. The fuel consumption rate was slightly reduced following the FAD installation. The FAD installation decreased PM and BC emissions in the diesel locomotive, especially coarse PM. The PM10 reductions achieved after FAD installation were 58.0, 69.7, and 34.2% for the constant velocity, stopping, and acceleration stages of the train's operation, respectively. The BC reduction rates were 29.5, 52.8, and 27.4% for the constant velocity, stopping, and acceleration stages, respectively.

  9. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion II

    NASA Astrophysics Data System (ADS)

    Lee, Scott

    2015-03-01

    In the second paper1 of this series, the effect of transverse femoral stresses due to locomotion in theropod dinosaurs of different sizes was examined for the case of an unchanging leg geometry. Students are invariably thrilled to learn about theropod dinosaurs, and this activity applies the concepts of torque and stress to the issue of theropod locomotion. In this paper, our model calculation of Ref. 1 is extended to incorporate the fact that larger animals run with straighter legs. As in Ref. 1, students use geometric data for the femora of theropod dinosaurs to analyze their locomotion abilities. This can either be an in-class activity or given as a homework problem. Larger theropods are found to be less athletic in their movements than smaller theropods since the stresses in the femora of large theropods are closer to breaking their legs than smaller theropods.

  10. A PHYSIOLOGIST'S PERSPECTIVE ON ROBOTIC EXOSKELETONS FOR HUMAN LOCOMOTION.

    PubMed

    Ferris, Daniel P; Sawicki, Gregory S; Daley, Monica A

    2007-09-01

    Technological advances in robotic hardware and software have enabled powered exoskeletons to move from science fiction to the real world. The objective of this article is to emphasize two main points for future research. First, the design of future devices could be improved by exploiting biomechanical principles of animal locomotion. Two goals in exoskeleton research could particularly benefit from additional physiological perspective: 1) reduction in the metabolic energy expenditure of the user while wearing the device, and 2) minimization of the power requirements for actuating the exoskeleton. Second, a reciprocal potential exists for robotic exoskeletons to advance our understanding of human locomotor physiology. Experimental data from humans walking and running with robotic exoskeletons could provide important insight into the metabolic cost of locomotion that is impossible to gain with other methods. Given the mutual benefits of collaboration, it is imperative that engineers and physiologists work together in future studies on robotic exoskeletons for human locomotion.

  11. Small step or giant leap? Human locomotion on Mars.

    PubMed

    Hawkey, Adam

    2004-01-01

    Human locomotion on Mars will be considerably different from on Earth. Optimum walking speeds will be approximately 30% lower and transitioning from a walk to a run will occur at a speed 25% slower. Peak vertical forces will be reduced by as much as 50%, and although ground contact time will remain constant with locomotion in 1 g, stride length and stride time will increase. During running on Mars airborne time will increase by approximately 80% in comparison to running on the Earth. On Mars, half as much energy will be required to travel the equivalent distance on Earth and it will be 65% more economical to run rather than to walk. Crews will, therefore, find themselves using a loping gait--a running-like action, with a slight upper body lean and an extended aerial phase, an unfamiliar gait in terrestrial locomotion.

  12. Towards a general neural controller for quadrupedal locomotion.

    PubMed

    Maufroy, Christophe; Kimura, Hiroshi; Takase, Kunikatsu

    2008-05-01

    Our study aims at the design and implementation of a general controller for quadruped locomotion, allowing the robot to use the whole range of quadrupedal gaits (i.e. from low speed walking to fast running). A general legged locomotion controller must integrate both posture control and rhythmic motion control and have the ability to shift continuously from one control method to the other according to locomotion speed. We are developing such a general quadrupedal locomotion controller by using a neural model involving a CPG (Central Pattern Generator) utilizing ground reaction force sensory feedback. We used a biologically faithful musculoskeletal model with a spine and hind legs, and computationally simulated stable stepping motion at various speeds using the neuro-mechanical system combining the neural controller and the musculoskeletal model. We compared the changes of the most important locomotion characteristics (stepping period, duty ratio and support length) according to speed in our simulations with the data on real cat walking. We found similar tendencies for all of them. In particular, the swing period was approximately constant while the stance period decreased with speed, resulting in a decreasing stepping period and duty ratio. Moreover, the support length increased with speed due to the posterior extreme position that shifted progressively caudally, while the anterior extreme position was approximately constant. This indicates that we succeeded in reproducing to some extent the motion of a cat from the kinematical point of view, even though we used a 2D bipedal model. We expect that such computational models will become essential tools for legged locomotion neuroscience in the future.

  13. Postural dependence of human locomotion during gait initiation

    PubMed Central

    Mille, Marie-Laure; Simoneau, Martin

    2014-01-01

    The initiation of human walking involves postural motor actions for body orientation and balance stabilization that must be effectively integrated with locomotion to allow safe and efficient transport. Our ability to coordinately adapt these functions to environmental or bodily changes through error-based motor learning is essential to effective performance. Predictive compensations for postural perturbations through anticipatory postural adjustments (APAs) that stabilize mediolateral (ML) standing balance normally precede and accompany stepping. The temporal sequencing between these events may involve neural processes that suppress stepping until the expected stability conditions are achieved. If so, then an unexpected perturbation that disrupts the ML APAs should delay locomotion. This study investigated how the central nervous system (CNS) adapts posture and locomotion to perturbations of ML standing balance. Healthy human adults initiated locomotion while a resistance force was applied at the pelvis to perturb posture. In experiment 1, using random perturbations, step onset timing was delayed relative to the APA onset indicating that locomotion was withheld until expected stability conditions occurred. Furthermore, stepping parameters were adapted with the APAs indicating that motor prediction of the consequences of the postural changes likely modified the step motor command. In experiment 2, repetitive postural perturbations induced sustained locomotor aftereffects in some parameters (i.e., step height), immediate but rapidly readapted aftereffects in others, or had no aftereffects. These results indicated both rapid but transient reactive adaptations in the posture and gait assembly and more durable practice-dependent changes suggesting feedforward adaptation of locomotion in response to the prevailing postural conditions. PMID:25231611

  14. 49 CFR 218.39 - Hump operations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD OPERATING PRACTICES Protection of Trains and Locomotives § 218.39 Hump operations. After June 30, 1984, each railroad that operates a remote control hump yard facility must have...

  15. 49 CFR 218.39 - Hump operations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD OPERATING PRACTICES Protection of Trains and Locomotives § 218.39 Hump operations. After June 30, 1984, each railroad that operates a remote control hump yard facility must have...

  16. Preferred and Energetically Optimal Transition Speeds During Backward Human Locomotion

    PubMed Central

    Hreljac, Alan; Imamura, Rodney; Escamilla, Rafael F.; Casebolt, Jeffrey; Sison, Mitell

    2005-01-01

    Some aspects of backward locomotion are similar to forward locomotion, while other aspects are not related to their forward counterpart. The backward preferred transition speed (BPTS) has never been directly compared to the energetically optimal transition speed (EOTS), nor has it been compared to the preferred transition speed (PTS) during forward locomotion. The purpose of this study was to determine whether the BPTS occurs at the EOTS, and to examine the relationship between the backward and forward preferred gait transition speeds. The preferred backward and forward transition speeds of 12 healthy, young subjects (7 males, 5 females) were determined after subjects were familiarized with forward and backward treadmill locomotion. On a subsequent day, subjects walked backward at speeds of 70, 80, 90, 100, and 110% of the BPTS and ran backward at speeds of 60, 75, 90, 100, and 120% of the BPTS while VO2 and RPE data were collected. After subtracting standing VO2, exercise VO2 was normalized to body mass and speed. For each subject, energy-speed curves for walking and running were fit to the normalized data points. The intersection of these curves was defined as the EOTS which was compared to the BPTS using a paired t-test (p < 0.05). RPE and VO2 at the BPTS were also compared between walking and running conditions, and the correlation between BPTS and PTS was calculated. The EOTS (1.85 ± 0.09 m·s-1) was significantly greater than the BPTS (1.63 ± 0.11 m·s-1). Even though RPE was equal for walking and running at the BPTS, VO2 was significantly greater when running. There was a strong correlation (r = 0.82) between the BPTS and the PTS. Similar to forward locomotion, the determinants of the BPTS must include factors other than metabolic energy. The gait transition during backward locomotion exhibits several similarities to its forward counterpart. Key Points The backward preferred transition speed (1.63 ± 0.11 m·s-1) was significantly less than the

  17. Biorobotics: using robots to emulate and investigate agile locomotion.

    PubMed

    Ijspeert, Auke J

    2014-10-10

    The graceful and agile movements of animals are difficult to analyze and emulate because locomotion is the result of a complex interplay of many components: the central and peripheral nervous systems, the musculoskeletal system, and the environment. The goals of biorobotics are to take inspiration from biological principles to design robots that match the agility of animals, and to use robots as scientific tools to investigate animal adaptive behavior. Used as physical models, biorobots contribute to hypothesis testing in fields such as hydrodynamics, biomechanics, neuroscience, and prosthetics. Their use may contribute to the design of prosthetic devices that more closely take human locomotion principles into account.

  18. Optimization of stable quadruped locomotion using mutual information

    NASA Astrophysics Data System (ADS)

    Silva, Pedro; Santos, Cristina P.; Polani, Daniel

    2013-10-01

    Central Pattern Generators (CPG)s have been widely used in the field of robotics to address the task of legged locomotion generation. The adequate configuration of these structures for a given platform can be accessed through evolutionary strategies, according to task dependent selection pressures. Information driven evolution, accounts for information theoretical measures as selection pressures, as an alternative to a fully task dependent selection pressure. In this work we exploit this concept and evaluate the use of mean Mutual Information, as a selection pressure towards a CPG configuration capable of faster, yet more coordinated and stabler locomotion than when only a task dependent selection pressure is used.

  19. Economic aspects of advanced coal-fired gas turbine locomotives

    NASA Technical Reports Server (NTRS)

    Liddle, S. G.; Bonzo, B. B.; Houser, B. C.

    1983-01-01

    Increases in the price of such conventional fuels as Diesel No. 2, as well as advancements in turbine technology, have prompted the present economic assessment of coal-fired gas turbine locomotive engines. A regenerative open cycle internal combustion gas turbine engine may be used, given the development of ceramic hot section components. Otherwise, an external combustion gas turbine engine appears attractive, since although its thermal efficiency is lower than that of a Diesel engine, its fuel is far less expensive. Attention is given to such a powerplant which will use a fluidized bed coal combustor. A life cycle cost analysis yields figures that are approximately half those typical of present locomotive engines.

  20. A dynamical systems analysis of afferent control in a neuromechanical model of locomotion: I. Rhythm generation

    NASA Astrophysics Data System (ADS)

    Spardy, Lucy E.; Markin, Sergey N.; Shevtsova, Natalia A.; Prilutsky, Boris I.; Rybak, Ilya A.; Rubin, Jonathan E.

    2011-10-01

    Locomotion in mammals is controlled by a spinal central pattern generator (CPG) coupled to a biomechanical limb system, with afferent feedback to the spinal circuits and CPG closing the control loop. We have considered a simplified model of this system, in which the CPG establishes a rhythm when a supra-spinal activating drive is present and afferent signals from a single-joint limb feed back to affect CPG operation. Using dynamical system methods, in a series of two papers we analyze the mechanisms by which this model produces oscillations, and the characteristics of these oscillations, in the closed- and open-loop regimes. In this first paper, we analyze the phase transition mechanisms operating within the CPG and use the results to explain how afferent feedback allows oscillations to occur at a wider range of drive values to the CPG than the range over which oscillations occur in the CPG without feedback, and then to comment on why stronger feedback leads to faster oscillations. Linking these transitions to structures in the phase plane associated with the limb segment clarifies how increased weights of afferent feedback to the CPG can restore locomotion after removal of supra-spinal drive to simulate spinal cord injury.

  1. Performance limits of low-temperature, continuous locomotion are exceeded when locomotion is intermittent in the ghost crab.

    PubMed

    Weinstein, R B; Full, R J

    1998-01-01

    Since a decline in temperature decreases aerobic capacity and slows the kinetics of exercise-to-rest transitions in ectotherms, we manipulated body temperature to better understand the performance limits of intermittent locomotion. Distance capacity (i.e., the total distance traveled before fatigue) of the ghost crab, Ocypode quadrata, was determined during acute exposure to 15 degrees C inside a treadmill-respirometer. Instead of exacerbating the near-paralyzing effects of low body temperature resulting from the frequent transitions, intermittent locomotion allowed animals to exceed the performance limits measured during steady-state locomotion. At low temperature, distance capacity for continuous locomotion at 0.04 m s(-1) (83% maximum aerobic speed) was 60 m. When 30 s of exercise at 0.08 m s(-1) (166% maximum aerobic speed) was alternated with 30 s of rest, distance capacity increased to 271 m, 4.5-fold greater than continuous locomotion at the same average speed (83% maximum aerobic speed). A 30-s pause following a 30-s exercise period was sufficient for maintaining low lactate concentrations in muscle and for partial resynthesis of arginine phosphate. A greater dependency on nonoxidative metabolism due to slowed oxygen uptake kinetics at low temperature resulted in a decreased duration of the critical exercise period, which increased performance relative to that measured at higher temperatures (30 s at 15 degrees C vs. 120 s at 24 degrees C). Despite the ghost crab's limited aerobic capacity at 15 degrees C, distance capacity during intermittent locomotion at low temperature can be comparable to that of a crab moving continuously at a body temperature 10 degrees C warmer. While endurance capacity is generally correlated with maximum aerobic speed, we have demonstrated that both locomotor behavior and body temperature must be considered when characterizing performance limits.

  2. 49 CFR 229.9 - Movement of non-complying locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... lite locomotive or a dead locomotive after the carrier has complied with the following: (1) A qualified... lite or dead within a yard, at speeds not in excess of 10 miles per hour, without meeting the... is responsible to insure that the movement may be safely made. (d) A dead locomotive may not...

  3. 49 CFR 229.9 - Movement of non-complying locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... lite locomotive or a dead locomotive after the carrier has complied with the following: (1) A qualified person shall determine— (i) That it is safe to move the locomotive; and (ii) The maximum speed and other... restrictions, if any; (vi) The destination; and (vii) The signature of the person making the...

  4. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    .... Cars essential to the movement of the steam locomotive and tender(s), including tool cars and a bunk... the engineer in charge of the defective steam locomotive and, if towed, the engineer in charge of the... movement, and notify in writing the engineer in charge of the defective steam locomotive and, if towed,...

  5. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    .... Cars essential to the movement of the steam locomotive and tender(s), including tool cars and a bunk... the engineer in charge of the defective steam locomotive and, if towed, the engineer in charge of the... movement, and notify in writing the engineer in charge of the defective steam locomotive and, if towed,...

  6. 40 CFR 1033.640 - Provisions for repowered and refurbished locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... parts consistent with the specifications of the Federal Railroad Administration. Otherwise, determine... provisions as other remanufactured locomotives, with the following exceptions: (1) Switch locomotives. (i) Prior to January 1, 2015, remanufactured Tier 0 switch locomotives that are deemed to be refurbished...

  7. 40 CFR 1033.640 - Provisions for repowered and refurbished locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... parts consistent with the specifications of the Federal Railroad Administration. Otherwise, determine... provisions as other remanufactured locomotives, with the following exceptions: (1) Switch locomotives. (i) Prior to January 1, 2015, remanufactured Tier 0 switch locomotives that are deemed to be refurbished...

  8. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Movement of non-complying steam locomotives. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a)...

  9. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Movement of non-complying steam locomotives. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a)...

  10. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Movement of non-complying steam locomotives. 230... RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION STEAM LOCOMOTIVE INSPECTION AND MAINTENANCE STANDARDS General General Inspection Requirements § 230.12 Movement of non-complying steam locomotives. (a)...

  11. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Specifications common to all steam locomotives... Specifications common to all steam locomotives. (a) Hand brakes. (1) Hand brakes will not be required on...) Locomotives having headlights which can not be safely and conveniently reached from pilot-beam or steam...

  12. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with...

  13. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with...

  14. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with...

  15. 49 CFR 223.17 - Identification of equipped locomotives, passenger cars and cabooses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... cars and cabooses. 223.17 Section 223.17 Transportation Other Regulations Relating to Transportation...-LOCOMOTIVES, PASSENGER CARS AND CABOOSES Specific Requirements § 223.17 Identification of equipped locomotives, passenger cars and cabooses. Each locomotive, passenger car and caboose that is fully equipped with...

  16. 49 CFR 222.21 - When must a locomotive horn be used?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false When must a locomotive horn be used? 222.21 Section 222.21 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... of Locomotive Horns § 222.21 When must a locomotive horn be used? (a) Except as provided in this...

  17. 49 CFR 222.21 - When must a locomotive horn be used?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false When must a locomotive horn be used? 222.21 Section 222.21 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD... of Locomotive Horns § 222.21 When must a locomotive horn be used? (a) Except as provided in this...

  18. Physiologic Responses to Motorized and Non-Motorized Locomotion Utilizing the International Space Station Treadmill

    NASA Technical Reports Server (NTRS)

    Smith, Cassie; Lee, Stuart MC; Laughlin, Mitzi; Loehr, James; Norcross, Jason; DeWitt, John; Hagan, R. D.

    2006-01-01

    Treadmill locomotion is used onboard the International Space Station (ISS) as a countermeasure to the effects of prolonged weightlessness. The treadmill operates in two modes: motorized (T-M) and non-motorized (T-NM). Little is known about the potential physiologic differences between modes which may affect countermeasure exercise prescription. PURPOSE: To quantify heart rate (HR), oxygen consumption (VO2), perceived exertion (RPE), and blood lactate (BLa) during T-M and T-NM locomotion at 2 and 4 mph in normal ambulatory subjects. METHODS: Twenty subjects (10 men, 10 women; 31+/-5 yr, 172+/-10 cm, 68+/-13 kg, mean SD) with a treadmill peakVO2 of 45.5+/-5.4 ml/kg/min (mean+/-SD) exercised on the ground-based ISS treadmill. Following a familiarization session in each mode, subjects completed two data collection sessions, T-M and T-NM in random order, at 2 and 4 mph. Subjects attempted to complete 5 min of exercise at each speed; if they could not maintain the speed, the trial was discontinued. At least 5 minutes of rest separated each speed trial, and at least 48 hrs separated each session. VO2 was measured continuously (metabolic gas analysis), while HR (HR monitor) and RPE (Borg Chart, 6-20 scale) were recorded each min. Not all subjects completed 5 min during each condition, therefore the mean of the min 3 and 4 was taken as representative of steady-state. BLa was measured (finger stick) within 2 min post-exercise. Paired t-tests were used to test for differences (p<0.05) between treadmill modes within the same speed. RESULTS: All twenty subjects completed at least 4 min of exercise during all conditions, except T-NM 4 mph when only 11 subjects completed the minimum exercise duration. VO2, HR, RPE and BLa were significantly higher during T-NM locomotion at both speeds.

  19. 40 CFR 1033.335 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... settings and component installations on randomly chosen locomotives in an engine family. (a) You must... least five percent of your annual production per model year per installer or ten per engine family per... (combined for all of your engine families). (c) The audit should be completed as soon as is practical...

  20. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion II

    ERIC Educational Resources Information Center

    Lee, Scott

    2015-01-01

    In the second paper of this series, the effect of transverse femoral stresses due to locomotion in theropod dinosaurs of different sizes was examined for the case of an unchanging leg geometry. Students are invariably thrilled to learn about theropod dinosaurs, and this activity applies the concepts of torque and stress to the issue of theropod…

  1. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion

    ERIC Educational Resources Information Center

    Lee, Scott

    2015-01-01

    In our first article on scaling in theropod dinosaurs, the longitudinal stress in the leg bones due to supporting the weight of the animal was studied and found not to control the dimensions of the femur. As a continuation of our study of elasticity in dinosaur bones, we now examine the transverse stress in the femur due to locomotion and find…

  2. Human locomotion and workload for simulated lunar and Martian environments.

    PubMed

    Newman, D J; Alexander, H L

    1993-08-01

    Human locomotion in simulated lunar and Martian environments is investigated. A unique human-rated underwater treadmill and an adjustable ballasting harness simulate partial gravity in order to better understand how gravity determines the biomechanics and energetics of human locomotion. This study has two research aspects, biomechanics and energetics. The fundamental biomechanics measurements are continuously recorded vertical forces as exerted by subjects of the treadmill which is instrumented with a force platform. Experimental results indicate that peak vertical force and stride frequency decrease as the gravity level is reduced. Foot contact time is independent of gravity level. Oxygen uptake measurements, VO2, constitute the energetics, or workload, data for this study. As theory predicts, locomotion energy requirements for lunar (1/6-g) and Martian (3/8-g) gravity levels are significantly less than at 1-g. The observed variation in workload with gravity level is nonmonotonic, however, in over half the subject population. The hypothesis is offered that energy expenditure increases for lunar, as compared with Martian, locomotion due to the subject "wasting energy" for stability and posture control in simulated lunar gravity. Biomechanics data could influence advanced spacesuit design and planetary habitat design, while workload data will help define oxygen requirements for planetary life support systems.

  3. 1. RESTORED GLOVER LOCOMOTIVE #81421 JUST WEST OF MARIETTA SQUARE; ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. RESTORED GLOVER LOCOMOTIVE #81421 JUST WEST OF MARIETTA SQUARE; 36 INCH GAUGE 2-6-0, BUILT 1-3-17. RETURNED FOR REPAIR AND RESALE IN 1923, LAST OFFERED FOR SALE IN 1931 FOR $750. - Glover Machine Works, 651 Butler Street, Marietta, Cobb County, GA

  4. 49 CFR 236.509 - Two or more locomotives coupled.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION... Train Stop, Train Control and Cab Signal Systems Standards § 236.509 Two or more locomotives coupled. The automatic train stop, train control or cab signal apparatus shall be arranged so that when two...

  5. 49 CFR 236.509 - Two or more locomotives coupled.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION... Train Stop, Train Control and Cab Signal Systems Standards § 236.509 Two or more locomotives coupled. The automatic train stop, train control or cab signal apparatus shall be arranged so that when two...

  6. 49 CFR 236.509 - Two or more locomotives coupled.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION... Train Stop, Train Control and Cab Signal Systems Standards § 236.509 Two or more locomotives coupled. The automatic train stop, train control or cab signal apparatus shall be arranged so that when two...

  7. 49 CFR 236.509 - Two or more locomotives coupled.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION... Train Stop, Train Control and Cab Signal Systems Standards § 236.509 Two or more locomotives coupled. The automatic train stop, train control or cab signal apparatus shall be arranged so that when two...

  8. 49 CFR 236.509 - Two or more locomotives coupled.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RULES, STANDARDS, AND INSTRUCTIONS GOVERNING THE INSTALLATION... Train Stop, Train Control and Cab Signal Systems Standards § 236.509 Two or more locomotives coupled. The automatic train stop, train control or cab signal apparatus shall be arranged so that when two...

  9. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... be used to perform any switching service after September 30, 1979 except passenger car switching... classification of cars according to commodity or destination; assembling of cars for train movements; changing the position of cars for purposes of loading, unloading, or weighing, placing of locomotives and...

  10. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... be used to perform any switching service after September 30, 1979 except passenger car switching... classification of cars according to commodity or destination; assembling of cars for train movements; changing the position of cars for purposes of loading, unloading, or weighing, placing of locomotives and...

  11. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... be used to perform any switching service after September 30, 1979 except passenger car switching... classification of cars according to commodity or destination; assembling of cars for train movements; changing the position of cars for purposes of loading, unloading, or weighing, placing of locomotives and...

  12. 21st Century Locomotive Technology: Quarterly Technical Status Report 28

    SciTech Connect

    Lembit Salasoo; Ramu Chandra

    2010-02-19

    Thermal testing of a subscale locomotive sodium battery module was initiated.to validate thermal models. The hybrid trip optimizer problem was formulated. As outcomes of this project, GE has proceeded to commercialize trip optimizer technology, and has initiated work on a state-of-the-art battery manufacturing plant for high energy density, sodium-based batteries.

  13. Optimization of two- and three-link snakelike locomotion

    NASA Astrophysics Data System (ADS)

    Jing, Fangxu; Alben, Silas

    2013-02-01

    We analyze two- and three-link planar snakelike locomotion and optimize the motion for efficiency. The locomoting system consists of two or three identical inextensible links connected via hinge joints, and the angles between the links are actuated as prescribed periodic functions of time. An essential feature of snake locomotion is frictional anisotropy: The forward, backward, and transverse coefficients of friction differ. The dynamics are studied analytically and numerically for small and large amplitudes of the internal angles. Efficiency is defined as the ratio between distance traveled and the energy expended within one period, i.e., the inverse of the cost of locomotion. The optimal set of coefficients of friction to maximize efficiency consists of a large backward coefficient of friction and a small transverse coefficient of friction, compared to the forward coefficient of friction. For the two-link case with a symmetrical motion, efficiency is maximized when the internal angle amplitude is approximately π/2 for a sufficiently large transverse coefficient. For the three-link case, the efficiency-maximizing paths are triangles in the parameter space of internal angles.

  14. Improved Usability of Locomotion Devices Using Human-Centric Taxonomy

    DTIC Science & Technology

    2009-03-01

    2. Internal Structure ................................................................... 39 3. The Payload...usability limitations simply by their location in the taxonomic structure . B. MOTIVATION While studies continue to develop locomotion devices, many do so...insight into the usability of a device simply by the its location within the taxonomic structure . The following list summarizes the taxa of the proposed

  15. More than a locomotive organelle: flagella in Escherichia coli.

    PubMed

    Zhou, Mingxu; Yang, Yang; Chen, Panlin; Hu, Huijie; Hardwidge, Philip R; Zhu, Guoqiang

    2015-11-01

    The flagellum is a locomotive organelle that allows bacteria to respond to chemical gradients. This review summarizes the current knowledge regarding Escherichia coli flagellin variants and the role of flagella in bacterial functions other than motility, including the relationship between flagella and bacterial virulence.

  16. Drosophila melanogaster (fruit fly) locomotion during a sounding rocket flight

    NASA Astrophysics Data System (ADS)

    Miller, Mark S.; Keller, Tony S.

    2008-05-01

    The locomotor activity of young Drosophila melanogaster (fruit fly) was studied during a Nike-Orion sounding rocket flight, which included a short-duration microgravity exposure. An infrared monitoring system was used to determine the activity level, instantaneous velocity, and continuous velocity of 240 (120 male, 120 female) fruit flies. Individual flies were placed in chambers that limit their motion to walking. Chambers were oriented both vertically and horizontally with respect to the rocket's longitudinal axis. Significant changes in Drosophila locomotion patterns were observed throughout the sounding rocket flight, including launch, microgravity exposure, payload re-entry, and after ocean impact. During the microgravity portion of the flight (3.8 min), large increases in all locomotion measurements for both sexes were observed, with some measurements doubling compared to pad (1 G) data. Initial effects of microgravity were probably delayed due to large accelerations from the payload despining immediately before entering microgravity. The results indicate that short-duration microgravity exposure has a large effect on locomotor activity for both males and females, at least for a short period of time. The locomotion increases may explain the increased male aging observed during long-duration exposure to microgravity. Studies focusing on long-duration microgravity exposure are needed to confirm these findings, and the relationship of increased aging and locomotion.

  17. Using Computational and Mechanical Models to Study Animal Locomotion

    PubMed Central

    Miller, Laura A.; Goldman, Daniel I.; Hedrick, Tyson L.; Tytell, Eric D.; Wang, Z. Jane; Yen, Jeannette; Alben, Silas

    2012-01-01

    Recent advances in computational methods have made realistic large-scale simulations of animal locomotion possible. This has resulted in numerous mathematical and computational studies of animal movement through fluids and over substrates with the purpose of better understanding organisms’ performance and improving the design of vehicles moving through air and water and on land. This work has also motivated the development of improved numerical methods and modeling techniques for animal locomotion that is characterized by the interactions of fluids, substrates, and structures. Despite the large body of recent work in this area, the application of mathematical and numerical methods to improve our understanding of organisms in the context of their environment and physiology has remained relatively unexplored. Nature has evolved a wide variety of fascinating mechanisms of locomotion that exploit the properties of complex materials and fluids, but only recently are the mathematical, computational, and robotic tools available to rigorously compare the relative advantages and disadvantages of different methods of locomotion in variable environments. Similarly, advances in computational physiology have only recently allowed investigators to explore how changes at the molecular, cellular, and tissue levels might lead to changes in performance at the organismal level. In this article, we highlight recent examples of how computational, mathematical, and experimental tools can be combined to ultimately answer the questions posed in one of the grand challenges in organismal biology: “Integrating living and physical systems.” PMID:22988026

  18. Moving Without Wheels: Educational Experiments in Robot Design and Locomotion

    DTIC Science & Technology

    2008-01-01

    Novel locomotion Lecture material presented comparative anatomies commenting on joint placement and limb lengths and the resulting effects on the...Figure 4: Six-legged walking robot. Designed for stability and speed. Figure 5: Turtle -like robot, designed for power. Figure 6

  19. Transmembrane channel-like (tmc) gene regulates Drosophila larval locomotion

    PubMed Central

    Guo, Yanmeng; Wang, Yuping; Zhang, Wei; Meltzer, Shan; Zanini, Damiano; Yu, Yue; Li, Jiefu; Cheng, Tong; Guo, Zhenhao; Wang, Qingxiu; Jacobs, Julie S.; Sharma, Yashoda; Eberl, Daniel F.; Göpfert, Martin C.; Jan, Lily Yeh; Jan, Yuh Nung; Wang, Zuoren

    2016-01-01

    Drosophila larval locomotion, which entails rhythmic body contractions, is controlled by sensory feedback from proprioceptors. The molecular mechanisms mediating this feedback are little understood. By using genetic knock-in and immunostaining, we found that the Drosophila melanogaster transmembrane channel-like (tmc) gene is expressed in the larval class I and class II dendritic arborization (da) neurons and bipolar dendrite (bd) neurons, both of which are known to provide sensory feedback for larval locomotion. Larvae with knockdown or loss of tmc function displayed reduced crawling speeds, increased head cast frequencies, and enhanced backward locomotion. Expressing Drosophila TMC or mammalian TMC1 and/or TMC2 in the tmc-positive neurons rescued these mutant phenotypes. Bending of the larval body activated the tmc-positive neurons, and in tmc mutants this bending response was impaired. This implicates TMC’s roles in Drosophila proprioception and the sensory control of larval locomotion. It also provides evidence for a functional conservation between Drosophila and mammalian TMCs. PMID:27298354

  20. 3. DETAIL OF INVERTED MINE LOCOMOTIVE OR "MOTOR," USED FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. DETAIL OF INVERTED MINE LOCOMOTIVE OR "MOTOR," USED FOR SURFACE HAULAGE OF MINE CARS, LOOKING SOUTHWEST; NOTE GEARING - Nuttallburg Mine Complex, Main Mine, North side of New River, 2.7 miles upstream from Fayette Landing, Lookout, Fayette County, WV

  1. Effect of rubber flooring on cow locomotion and gene expression

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to evaluate the effect of 2 dairy cow housing systems on cow locomotion and expression of genes associated with lameness, during the dry and peri-parturient period. Cows were assigned to free-stall housing with either rubber (RUB; n=13) or concrete (CON; n=14) at the feed-f...

  2. Energetic Extremes in Aquatic Locomotion by Coral Reef Fishes

    PubMed Central

    Fulton, Christopher J.; Johansen, Jacob L.; Steffensen, John F.

    2013-01-01

    Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s−1) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed. PMID:23326566

  3. Energetic extremes in aquatic locomotion by coral reef fishes.

    PubMed

    Fulton, Christopher J; Johansen, Jacob L; Steffensen, John F

    2013-01-01

    Underwater locomotion is challenging due to the high friction and resistance imposed on a body moving through water and energy lost in the wake during undulatory propulsion. While aquatic organisms have evolved streamlined shapes to overcome such resistance, underwater locomotion has long been considered a costly exercise. Recent evidence for a range of swimming vertebrates, however, has suggested that flapping paired appendages around a rigid body may be an extremely efficient means of aquatic locomotion. Using intermittent flow-through respirometry, we found exceptional energetic performance in the Bluelined wrasse Stethojulis bandanensis, which maintains tuna-like optimum cruising speeds (up to 1 metre s(-1)) while using 40% less energy than expected for their body size. Displaying an exceptional aerobic scope (22-fold above resting), streamlined rigid-body posture, and wing-like fins that generate lift-based thrust, S. bandanensis literally flies underwater to efficiently maintain high optimum swimming speeds. Extreme energetic performance may be key to the colonization of highly variable environments, such as the wave-swept habitats where S. bandanensis and other wing-finned species tend to occur. Challenging preconceived notions of how best to power aquatic locomotion, biomimicry of such lift-based fin movements could yield dramatic reductions in the power needed to propel underwater vehicles at high speed.

  4. Fish locomotion: insights from both simple and complex mechanical models

    NASA Astrophysics Data System (ADS)

    Lauder, George

    2015-11-01

    Fishes are well-known for their ability to swim and maneuver effectively in the water, and recent years have seen great progress in understanding the hydrodynamics of aquatic locomotion. But studying freely-swimming fishes is challenging due to difficulties in controlling fish behavior. Mechanical models of aquatic locomotion have many advantages over studying live animals, including the ability to manipulate and control individual structural or kinematic factors, easier measurement of forces and torques, and the ability to abstract complex animal designs into simpler components. Such simplifications, while not without their drawbacks, facilitate interpretation of how individual traits alter swimming performance and the discovery of underlying physical principles. In this presentation I will discuss the use of a variety of mechanical models for fish locomotion, ranging from simple flexing panels to complex biomimetic designs incorporating flexible, actively moved, fin rays on multiple fins. Mechanical devices have provided great insight into the dynamics of aquatic propulsion and, integrated with studies of locomotion in freely-swimming fishes, provide new insights into how fishes move through the water.

  5. Locomotion in Stroke Subjects: Interactions between Unaffected and Affected Sides

    ERIC Educational Resources Information Center

    Kloter, Evelyne; Wirz, Markus; Dietz, Volker

    2011-01-01

    The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm…

  6. 13. VIEW OF RAILROAD EXHIBIT AT EL PORTAL. SHAY LOCOMOTIVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    13. VIEW OF RAILROAD EXHIBIT AT EL PORTAL. SHAY LOCOMOTIVE IS FROM THE HETCH HETCHY RAILROAD. CABOOSE IS FROM THE YOSEMITE VALLEY RAILROAD. FOREST ROAD IN FOREGROUND IS THE ALIGNMENT OF THE YOSEMITE VALLEY RAILROAD. LOOKING W. GIS: N-37 40 27.0 / W-119 47 10.5 - Yosemite National Park Roads & Bridges, Yosemite Village, Mariposa County, CA

  7. Locomotion pattern and trunk musculoskeletal architecture among Urodela.

    PubMed

    Omura, Ayano; Ejima, Ken-Ichiro; Honda, Kazuya; Anzai, Wataru; Taguchi, Yuki; Koyabu, Daisuke; Endo, Hideki

    2015-04-01

    We comparatively examined the trunk musculature and prezygapophyseal angle of mid-trunk vertebra in eight urodele species with different locomotive modes (aquatic Siren intermedia, Amphiuma tridactylum, Necturus maculosus and Andrias japonicus; semi-aquatic Cynops pyrrhogaster, Cynops ensicauda; and terrestrial Hynobius nigrescens, Hynobius lichenatus and Ambystoma tigrinum). We found that the more terrestrial species were characterized by larger dorsal and abdominal muscle weight ratios compared with those of the more aquatic species, whereas muscle ratios of the lateral hypaxial musculature were larger in the more aquatic species. The lateral hypaxial muscles were thicker in the more aquatic species, whereas the M. rectus abdominis was more differentiated in the more terrestrial species. Our results suggest that larger lateral hypaxial muscles function for lateral bending during underwater locomotion in aquatic species. Larger dorsalis and abdominal muscles facilitate resistance against sagittal extension of the trunk, stabilization and support of the ventral contour line against gravity in terrestrial species. The more aquatic species possessed a more horizontal prezygapophyseal angle for more flexible lateral locomotion. In contrast, the more terrestrial species have an increasingly vertical prezygapophyseal angle to provide stronger column support against gravity. Thus, we conclude trunk structure in urodeles differs clearly according to their locomotive modes.

  8. 40 CFR 1033.335 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Remanufacturer Production Line Testing and Audit Programs § 1033.335 Remanufactured locomotives: installation... 208 and 213 of the Clean Air Act. Our production-line auditing conformed completely with the... least five percent of your annual production per model year per installer or ten per engine family...

  9. 40 CFR 1033.335 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Remanufacturer Production Line Testing and Audit Programs § 1033.335 Remanufactured locomotives: installation... 208 and 213 of the Clean Air Act. Our production-line auditing conformed completely with the... least five percent of your annual production per model year per installer or ten per engine family...

  10. 40 CFR 1033.335 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Remanufacturer Production Line Testing and Audit Programs § 1033.335 Remanufactured locomotives: installation... 208 and 213 of the Clean Air Act. Our production-line auditing conformed completely with the... least five percent of your annual production per model year per installer or ten per engine family...

  11. 40 CFR 1033.335 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Remanufacturer Production Line Testing and Audit Programs § 1033.335 Remanufactured locomotives: installation... 208 and 213 of the Clean Air Act. Our production-line auditing conformed completely with the... least five percent of your annual production per model year per installer or ten per engine family...

  12. 16. Joe Murphy, Jr., Photographer, circa 190914 LOCOMOTIVE NO. 148 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    16. Joe Murphy, Jr., Photographer, circa 1909-14 LOCOMOTIVE NO. 148 STEAMS UP LITTLE RIVER GORGE, CA. 1909-14. LITTLE RIVER ROAD WAS CONSTRUCTED OVER THIS RIGHT OF WAY IN 1932. - Great Smoky Mountains National Park Roads & Bridges, Gatlinburg, Sevier County, TN

  13. Gaze Stabilization During Locomotion Requires Full Body Coordination

    NASA Technical Reports Server (NTRS)

    Mulavara, A. P.; Miller, C. A.; Houser, J.; Richards, J. T.; Bloomberg, J. J.

    2001-01-01

    Maintaining gaze stabilization during locomotion places substantial demands on multiple sensorimotor subsystems for precise coordination. Gaze stabilization during locomotion requires eye-head-trunk coordination (Bloomberg, et al., 1997) as well as the regulation of energy flow or shock-wave transmission through the body at high impact phases with the support surface (McDonald, et al., 1997). Allowing these excessive transmissions of energy to reach the head may compromise gaze stability. Impairments in these mechanisms may lead to the oscillopsia and decreased dynamic visual acuity seen in crewmembers returning from short and long duration spaceflight, as well as in patients with vestibular disorders (Hillman, et al., 1999). Thus, we hypothesize that stabilized gaze during locomotion results from full-body coordination of the eye-head-trunk system combined with the lower limb apparatus. The goal of this study was to determine how multiple, interdependent full- body sensorimotor subsystems aiding gaze stabilization during locomotion are functionally coordinated, and how they adaptively respond to spaceffight.

  14. A Field Test of Festinger's Substitute Locomotion Theory.

    ERIC Educational Resources Information Center

    Stewart, Lea P.; Gudykunst, William B.

    1986-01-01

    Provides evidence for rejecting Festinger's Substitute Locomotion Theory of organizational communication. Demonstrates a clear difference between formal and informal channels of upward communication. Indicates that high mobility individuals communicate significantly more with their supervisors than low mobility individuals and that males…

  15. 15. Photocopied August 1978. LOCOMOTIVE CRANE IN THE ROCK CUT, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    15. Photocopied August 1978. LOCOMOTIVE CRANE IN THE ROCK CUT, AUGUST 21, 1900. LOADING DUMP CARS. A STEAM SHOVEL LOADING DUMP CARS IS VISIBLE IN THE LEFT BACKGROUND. (61) - Michigan Lake Superior Power Company, Portage Street, Sault Ste. Marie, Chippewa County, MI

  16. The effect of activation level on muscle function during locomotion: are optimal lengths and velocities always used?

    PubMed Central

    Holt, N. C.; Azizi, E.

    2016-01-01

    Skeletal muscle exhibits broad functional diversity, despite its inherent length and velocity constraints. The observed variation in morphology and physiology is assumed to have evolved to allow muscle to operate at its optimal length and velocity during locomotion. Here, we used the variation in optimum lengths and velocities that occurs with muscle activation level to experimentally test this assumption. Muscle ergometry and sonomicrometry were used to characterize force–length and power–velocity relationships, and in vivo operating lengths and velocities, at a range of activation levels. Operating lengths and velocities were mapped onto activation level specific force–length and power–velocity relationships to determine whether they tracked changing optima. Operating velocities decreased in line with decreased optimal velocities, suggesting that optimal velocities are always used. However, operating lengths did not change with changing optima. At high activation levels, fibres used an optimal range of lengths. However, at lower activation levels, fibres appeared to operate on the ascending limb of sub-maximally activated force–length relationships. This suggests that optimal lengths are only used when demand is greatest. This study provides the first mapping of operating lengths to activation level-specific optima, and as such, provides insight into our assumptions about the factors that determine muscle performance during locomotion. PMID:26817770

  17. Changes in gravity inhibit lymphocyte locomotion through type I collagen

    NASA Technical Reports Server (NTRS)

    Pellis, N. R.; Goodwin, T. J.; Risin, D.; McIntyre, B. W.; Pizzini, R. P.; Cooper, D.; Baker, T. L.; Spaulding, G. F.

    1997-01-01

    Immunity relies on the circulation of lymphocytes through many different tissues including blood vessels, lymphatic channels, and lymphoid organs. The ability of lymphocytes to traverse the interstitium in both nonlymphoid and lymphoid tissues can be determined in vitro by assaying their capacity to locomote through Type I collagen. In an attempt to characterize potential causes of microgravity-induced immunosuppression, we investigated the effects of simulated microgravity on human lymphocyte function in vitro using a specialized rotating-wall vessel culture system developed at the Johnson Space Center. This very low shear culture system randomizes gravitational vectors and provides an in vitro approximation of microgravity. In the randomized gravity of the rotating-wall vessel culture system, peripheral blood lymphocytes did not locomote through Type I collagen, whereas static cultures supported normal movement. Although cells remained viable during the entire culture period, peripheral blood lymphocytes transferred to unit gravity (static culture) after 6 h in the rotating-wall vessel culture system were slow to recover and locomote into collagen matrix. After 72 h in the rotating-wall vessel culture system and an additional 72 h in static culture, peripheral blood lymphocytes did not recover their ability to locomote. Loss of locomotory activity in rotating-wall vessel cultures appears to be related to changes in the activation state of the lymphocytes and the expression of adhesion molecules. Culture in the rotating-wall vessel system blunted the ability of peripheral blood lymphocytes to respond to polyclonal activation with phytohemagglutinin. Locomotory response remained intact when peripheral blood lymphocytes were activated by anti-CD3 antibody and interleukin-2 prior to introduction into the rotating-wall vessel culture system. Thus, in addition to the systemic stress factors that may affect immunity, isolated lymphocytes respond to gravitational changes

  18. Separation of Propulsive and Adhesive Traction Stresses in Locomoting Keratocytes

    PubMed Central

    Oliver, Tim; Dembo, Micah; Jacobson, Ken

    1999-01-01

    Strong, actomyosin-dependent, pinching tractions in steadily locomoting (gliding) fish keratocytes revealed by traction imaging present a paradox, since only forces perpendicular to the direction of locomotion are apparent, leaving the actual propulsive forces unresolved. When keratocytes become transiently “stuck” by their trailing edge and adopt a fibroblast-like morphology, the tractions opposing locomotion are concentrated into the tail, leaving the active pinching and propulsive tractions clearly visible under the cell body. Stuck keratocytes can develop ∼1 mdyn (10,000 pN) total propulsive thrust, originating in the wings of the cell. The leading lamella develops no detectable propulsive traction, even when the cell pulls on its transient tail anchorage. The separation of propulsive and adhesive tractions in the stuck phenotype leads to a mechanically consistent hypothesis that resolves the traction paradox for gliding keratocytes: the propulsive tractions driving locomotion are normally canceled by adhesive tractions resisting locomotion, leaving only the pinching tractions as a resultant. The resolution of the traction pattern into its components specifies conditions to be met for models of cytoskeletal force production, such as the dynamic network contraction model (Svitkina, T.M., A.B. Verkhovsky, K.M. McQuade, and G.G. Borisy. 1997. J. Cell Biol. 139:397–415). The traction pattern associated with cells undergoing sharp turns differs markedly from the normal pinching traction pattern, and can be accounted for by postulating an asymmetry in contractile activity of the opposed lateral wings of the cell. PMID:10225959

  19. A proposal for the definition of terms related to locomotion of leukocytes and other cells*

    PubMed Central

    1980-01-01

    There is currently much confusion of terms relating to locomotion of leukocytes and other cells. Standardized and precise use of terms is, however, indispensable for analysis of the basic mechanisms controlling such locomotion. The present proposal is intended to serve as a basis for a standardized system of reporting locomotor behaviour of leukocytes and other cells and their responses to environmental stimuli. Definitions of the terms random locomotion, directional locomotion, chemotaxis, chemokinesis, and intrinsic locomotor capacity are proposed. Examples are given to demonstrate the application of the terms in the experimental and clinical analysis of cell locomotion. PMID:6968255

  20. A Locomotion Intent Prediction System Based on Multi-Sensor Fusion

    PubMed Central

    Chen, Baojun; Zheng, Enhao; Wang, Qining

    2014-01-01

    Locomotion intent prediction is essential for the control of powered lower-limb prostheses to realize smooth locomotion transitions. In this research, we develop a multi-sensor fusion based locomotion intent prediction system, which can recognize current locomotion mode and detect locomotion transitions in advance. Seven able-bodied subjects were recruited for this research. Signals from two foot pressure insoles and three inertial measurement units (one on the thigh, one on the shank and the other on the foot) are measured. A two-level recognition strategy is used for the recognition with linear discriminate classifier. Six kinds of locomotion modes and ten kinds of locomotion transitions are tested in this study. Recognition accuracy during steady locomotion periods (i.e., no locomotion transitions) is 99.71% ± 0.05% for seven able-bodied subjects. During locomotion transition periods, all the transitions are correctly detected and most of them can be detected before transiting to new locomotion modes. No significant deterioration in recognition performance is observed in the following five hours after the system is trained, and small number of experiment trials are required to train reliable classifiers. PMID:25014097

  1. Effective Stimulus Parameters for Directed Locomotion in Madagascar Hissing Cockroach Biobot

    PubMed Central

    Erickson, Jonathan C.; Shingiro, Aristide; Bowen, Thomas

    2015-01-01

    Swarms of insects instrumented with wireless electronic backpacks have previously been proposed for potential use in search and rescue operations. Before deploying such biobot swarms, an effective long-term neural-electric stimulus interface must be established, and the locomotion response to various stimuli quantified. To this end, we studied a variety of pulse types (mono- vs. bipolar; voltage- vs. current-controlled) and shapes (amplitude, frequency, duration) to parameters that are most effective for evoking locomotion along a desired path in the Madagascar hissing cockroach (G. portentosa) in response to antennal and cercal stimulation. We identified bipolar, 2 V, 50 Hz, 0.5 s voltage controlled pulses as being optimal for evoking forward motion and turns in the expected contraversive direction without habituation in ≈50% of test subjects, a substantial increase over ≈10% success rates previously reported. Larger amplitudes for voltage (1–4 V) and current (50–150 μA) pulses generally evoked larger forward walking (15.6–25.6 cm; 3.9–5.6 cm/s) but smaller concomitant turning responses (149 to 80.0 deg; 62.8 to 41.2 deg/s). Thus, the radius of curvature of the initial turn-then-run locomotor response (≈10–25 cm) could be controlled in a graded manner by varying the stimulus amplitude. These findings could be used to help optimize stimulus protocols for swarms of cockroach biobots navigating unknown terrain. PMID:26308337

  2. Development of a robotic endoscope that locomotes in the colon with flexible helical fins.

    PubMed

    Shikanai, M; Murai, N; Itoh, K; Ishii, H; Takanishi, A; Tanoue, K; Ieiri, S; Konishi, K; Hasizume, M

    2009-01-01

    The purpose of this study was to develop a robotic endoscope that is low invasive, easy to operate and capable of locomotion from the rectum to the appendix in the human body. We believe that it would contribute to relieving pain in patients. We therefore developed a robotic endoscope that consists of a front and rear body with clockwise and anticlockwise helical fins, respectively. The front and rear bodies are connected via a DC motor. This robot moves forward in the colon by rotating the front body in the clockwise direction and the rear body in the anticlockwise direction. In addition, the radius of each helical fin can be changed by blowing air into a balloon implemented under each fin using an air compressor. Before experiments with animals, we performed experiments to evaluate the mechanical performance and safety of the robot. We confirmed that the maximum radius of the fins was less than the maximum radius of the colon by blowing air continuously into the balloons. We then confirmed that the robot can locomote in the colon without invasion of scratch and make short hole by performing an in-vivo experiment in live swine.

  3. Locomotive emissions monitoring program annual report, 1995

    SciTech Connect

    1997-12-31

    The report is to include data on the traffic moved and the fuel consumed, estimates of the consequent emissions of certain exhaust gases, and information on any improvements in equipment or operating practices that will lead to reduced emissions. This is the first such annual report.

  4. The neural basis of the locomotion of nematodes

    NASA Astrophysics Data System (ADS)

    Erdös, Paul; Niebur, Ernst

    A model of electrotonic neurons is presented which allows computer simulation of a physiologically realistic neural network, such as that found in nematodes. The undulatory locomotion of Caenorhabditis elegans is investigated by solving the equations of motion of a segmented model of the discretized body taking into account all internal and external forces. The spatio-temporal muscle excitation patterns which produce locomotion are determined, and it is concluded that these are most probably generated by stretch receptor cells and signals which globally turn on or off the neural circuitry governing forward or backward motion. The results are illustrated in the form of a computer generated videotape and compared with the observed motion of a nematode.

  5. Two techniques for measuring locomotion impact forces during zero G

    NASA Technical Reports Server (NTRS)

    Greenisen, Michael C.; Smith, Richard A.; Klute, Glenn K.; Mccaulley, James B.

    1993-01-01

    A load-cell-instrumented treadmill mated to a Kistler force plate was used to investigate two methods of force measurement instrumentation during treadmill ambulation in zero g, created by parabolic flight on NASA's KC-135 aircraft. Current spaceflight treadmills do not have adequate instrumentation to determine the resultant foot impact force applied during restrained ambulation. Accurate measurement of foot-ground reaction forces is critical in attaining proper one-g loading, therefore ensuring proper musculoskeletal conditioning. Treadmill instrumentation and force plate measurements were compared for frequency response and linearity. Locomotion impact data were also collected under one-g laboratory settings and in Keplerian flight. The first resonant frequency for both techniques was found to be well above the primary frequency content of the locomotive forces. Peak impact forces measured by the two systems compared to within 10 percent.

  6. Spinal corollary discharge modulates motion sensing during vertebrate locomotion

    PubMed Central

    Chagnaud, Boris P.; Banchi, Roberto; Simmers, John; Straka, Hans

    2015-01-01

    During active movements, neural replicas of the underlying motor commands may assist in adapting motion-detecting sensory systems to an animal's own behaviour. The transmission of such motor efference copies to the mechanosensory periphery offers a potential predictive substrate for diminishing sensory responsiveness to self-motion during vertebrate locomotion. Here, using semi-isolated in vitro preparations of larval Xenopus, we demonstrate that shared efferent neural pathways to hair cells of vestibular endorgans and lateral line neuromasts express cyclic impulse bursts during swimming that are directly driven by spinal locomotor circuitry. Despite common efferent innervation and discharge patterns, afferent signal encoding at the two mechanosensory peripheries is influenced differentially by efference copy signals, reflecting the different organization of body/water motion-detecting processes in the vestibular and lateral line systems. The resultant overall gain reduction in sensory signal encoding in both cases, which likely prevents overstimulation, constitutes an adjustment to increased stimulus magnitudes during locomotion. PMID:26337184

  7. Principle of Spectral Reciprocity in Biomechanics of Locomotion and Rehabilitation

    PubMed Central

    Pitkin, Mark

    2016-01-01

    Providing the technical means to prevent collapse or falls in patients with different types of pathology in motion and balance control is one of the traditional problems in rehabilitation engineering. A means of addressing the problem using assistive devices, including prostheses, is to restrict the mobility in certain anatomical or artificial joints by applying corsets, braces, brakes and locks. The restriction of mobility in the joints increases local stiffnesses, and in a sense, tunes the spectrum of oscillations in these joints out of resonantly dangerous zones. So far, these efforts for limiting unwanted mobility are mostly empirical within rehabilitation technologies, and we suggest that they can be optimized with algorithms for controlling the spectrum of oscillations used in multi-linked technical systems. Further, we suggest that tuning out of resonance is inseparable from the phenomenon of tuning into resonance that is widely recognized in biomechanics of locomotion. These considerations result in our postulating the principle of spectral reciprocity in locomotion. PMID:27066156

  8. Electrokinetic locomotion due to Reaction Induced Charge Auto-Electrophoresis

    NASA Astrophysics Data System (ADS)

    Moran, Jeffrey; Posner, Jonathan

    2010-11-01

    Synthetic nanomotors, like their biological counterparts, propel themselves through aqueous solutions by harvesting chemical energy from their local environment and converting it to mechanical energy. We study bimetallic rod-shaped particles which move autonomously by catalytically decomposing hydrogen peroxide to oxygen and water. We present a scaling analysis and computational simulations that describe the locomotion of bimetallic rod-shaped motors in hydrogen peroxide solutions due to reaction-induced charge auto-electrophoresis. The model shows that the locomotion results from electrical body forces in the surrounding fluid, which are generated by a coupling of an asymmetric dipolar charge density distribution and the electric field it generates. The simulations make the predictions, in agreement with experiment, that the rods' velocity depends linearly on both the surface charge and reaction rate.

  9. Direct measurements of drag forces in C. elegans crawling locomotion.

    PubMed

    Rabets, Yegor; Backholm, Matilda; Dalnoki-Veress, Kari; Ryu, William S

    2014-10-21

    With a simple and versatile microcantilever-based force measurement technique, we have probed the drag forces involved in Caenorhabditis elegans locomotion. As a worm crawls on an agar surface, we found that substrate viscoelasticity introduces nonlinearities in the force-velocity relationships, yielding nonconstant drag coefficients that are not captured by original resistive force theory. A major contributing factor to these nonlinearities is the formation of a shallow groove on the agar surface. We measured both the adhesion forces that cause the worm's body to settle into the agar and the resulting dynamics of groove formation. Furthermore, we quantified the locomotive forces produced by C. elegans undulatory motions on a wet viscoelastic agar surface. We show that an extension of resistive force theory is able to use the dynamics of a nematode's body shape along with the measured drag coefficients to predict the forces generated by a crawling nematode.

  10. The coal-fired gas turbine locomotive - A new look

    NASA Technical Reports Server (NTRS)

    Liddle, S. G.; Bonzo, B. B.; Purohit, G. P.

    1983-01-01

    Advances in turbomachine technology and novel methods of coal combustion may have made possible the development of a competitive coal fired gas turbine locomotive engine. Of the combustor, thermodynamic cycle, and turbine combinations presently assessed, an external combustion closed cycle regenerative gas turbine with a fluidized bed coal combustor is judged to be the best suited for locomotive requirements. Some merit is also discerned in external combustion open cycle regenerative systems and internal combustion open cycle regenerative gas turbine systems employing a coal gasifier. The choice of an open or closed cycle depends on the selection of a working fluid and the relative advantages of loop pressurization, with air being the most attractive closed cycle working fluid on the basis of cost.

  11. Piezoelectric vibration-driven locomotion systems - Exploiting resonance and bistable dynamics

    NASA Astrophysics Data System (ADS)

    Fang, Hongbin; Wang, K. W.

    2017-03-01

    While a piezoelectric-based vibration-driven system is an excellent candidate for actuating small-size crawling-type locomotion robots, it has the major drawback of limited stroke output that would severely constraint the system's locomotion performance. In this paper, to advance the state of the art, we propose two novel designs of piezoelectric vibration-driven locomotion systems. The first utilizes the resonant amplification concept, and the second explores the design of a bistable device. While these two ideas have been explored for piezoelectric actuation amplification in general, they have never been exploited for crawling-type robotic locomotion. Numerical analyses on both systems reveal that resonance and bistability can substantially increase the systems' average locomotion speed. Moreover, this research shows that with bistability, the system is able to output high average locomotion speed in a wider frequency band, possess multiple locomotion modes, and achieve fast switches among them. Through proof-of-concept prototypes, the predicted locomotion performance improvements brought by resonance and bistability are verified. Finally, the basin stability is evaluated to systematically describe the occurring probability of certain locomotion behavior of the bistable system, which would provide useful guideline to the design and control of bistable vibration-driven locomotion systems.

  12. Locomotion of electrocatalytic nanomotors due to reaction induced charge autoelectrophoresis

    NASA Astrophysics Data System (ADS)

    Moran, J. L.; Wheat, P. M.; Posner, J. D.

    2010-06-01

    Bimetallic rod-shaped nanomotors swim autonomously in hydrogen peroxide solutions. Here, we present a scaling analysis, computational simulations, and experimental data that show that the nanomotor locomotion is driven by fluid slip around the nanomotor surface due to electrical body forces. The body forces are generated by a coupling of charge density and electric fields induced by electrochemical reactions occurring on the nanomotor surface. We describe the dependence of nanomotor motion on the nanomotor surface potential and reaction-driven flux.

  13. Performance analysis of jump-gliding locomotion for miniature robotics.

    PubMed

    Vidyasagar, A; Zufferey, Jean-Christohphe; Floreano, Dario; Kovač, M

    2015-03-26

    Recent work suggests that jumping locomotion in combination with a gliding phase can be used as an effective mobility principle in robotics. Compared to pure jumping without a gliding phase, the potential benefits of hybrid jump-gliding locomotion includes the ability to extend the distance travelled and reduce the potentially damaging impact forces upon landing. This publication evaluates the performance of jump-gliding locomotion and provides models for the analysis of the relevant dynamics of flight. It also defines a jump-gliding envelope that encompasses the range that can be achieved with jump-gliding robots and that can be used to evaluate the performance and improvement potential of jump-gliding robots. We present first a planar dynamic model and then a simplified closed form model, which allow for quantification of the distance travelled and the impact energy on landing. In order to validate the prediction of these models, we validate the model with experiments using a novel jump-gliding robot, named the 'EPFL jump-glider'. It has a mass of 16.5 g and is able to perform jumps from elevated positions, perform steered gliding flight, land safely and traverse on the ground by repetitive jumping. The experiments indicate that the developed jump-gliding model fits very well with the measured flight data using the EPFL jump-glider, confirming the benefits of jump-gliding locomotion to mobile robotics. The jump-glide envelope considerations indicate that the EPFL jump-glider, when traversing from a 2 m height, reaches 74.3% of optimal jump-gliding distance compared to pure jumping without a gliding phase which only reaches 33.4% of the optimal jump-gliding distance. Methods of further improving flight performance based on the models and inspiration from biological systems are presented providing mechanical design pathways to future jump-gliding robot designs.

  14. Locomotion with Loads: Practical Techniques for Predicting Performance Outcomes

    DTIC Science & Technology

    2013-05-01

    and American College of Sports Medicine (ACSM) equations. Both use body weight and walking speed, but not stature to predict metabolic rates...ambulatory monitoring: using foot contact time to estimate the metabolic cost of locomotion. In: Emerging Technologies for Nutrition Research: Potential for...slopes. J Appl Physiol. 93, 1039-1046. American College of Sports Medicine. (2006). American College of Sports Medicine Guidelines for Graded

  15. A Cockroach-Like Hexapod Robot for Natural Terrain Locomotion.

    DTIC Science & Technology

    2007-11-02

    during treadmill running in the cockroach , Blaberus discoidalis: JJ. Fast running. /. Comp. Physiol. A. 182:23- 33. Presentations R. Beer gave an...PERFORMANCE REPORT A Cockroach -Like Hexapod Robot for Natural Terrain Locomotion Grant N00014-96-1-0708 Period of Performance: 3 Years Starting...Date: January 1,1996 June 24, 1998 Randall D. Beer Principal Investigator Department of Computer Engineering and Science Department of Biology

  16. Discharge patterns of hindlimb motoneurons during normal cat locomotion.

    PubMed

    Hoffer, J A; O'Donovan, M J; Pratt, C A; Loeb, G E

    1981-07-24

    Long-term recording from single lumbar motoneurons of intact cats revealed activation patterns fundamentally different from those seen in decerebrate preparations. In intact cats, motoneuron bursts showed marked rate modulation without initial doublets. Each unit's frequencygram generally resembled the envelope of the gross electromyogram simultaneously recorded from the corresponding muscle. Average and peak discharge rates increased for faster gaits. These findings suggest that, in cat locomotion, rate modulation is a more important contributor to force regulation than was previously thought.

  17. Robotic exploration of surfaces and its application to legged locomotion

    NASA Astrophysics Data System (ADS)

    Sinha, Pramath Raj

    1991-02-01

    Material properties like penetrability, compliance, and surface roughness are important in the characterization of the environment. While concentrating on issues of geometry and shape, researchers in perceptual robotics, until recently, have not quite addressed the issue of the extraction of material properties from the environment. The goal of this research is to design and implement a robotic system that will actively explore a surface to extract its material characteristics. Further the relevance of material properties in the legged locomotion of robots is also recognized and our research objectives are extended towards building a robotic system for exploration such that is actively perceives material properties during the process of legged locomotion. The chosen approach to the design and implementation of such a robotic system is to first select an appropriate environment model and then to design exploratory procedures salient to each attribute of interest. These exploratory procedures are then implemented through an experimental setup and the results show that material properties can be reliably measured. The design, implementation, and results of a framework for surface exploration to recover material properties are presented. Further, the exploratory procedures for exploration are integrated into an active perceptual scheme for legged locomotion. The perceptual scheme is designed around creating the ability for the robot to sense variations in terrain properties while it is walking, so that it may be able to avoid sinking, slipping, and falling due to unexpected changes in the terrain properties, and make suitable changes in its foot forces to continue locomotion. Finite element simulations of the foot-terrain interaction are used to justify some of the strategies used in this active perceptual scheme. The active perceptual scheme is implemented by simulating a leg-ankle-foot system with a PUMA arm-complaint wrist-foot system and an accelerometer mounted on

  18. Some historical reflections on the neural control of locomotion.

    PubMed

    Clarac, François

    2008-01-01

    Thought on the neural control of locomotion dates back to antiquity. In this article, however, the focus is more recent by starting with some major 17th century concepts, which were developed by René Descartes, a French philosopher; Thomas Willis, an English anatomist; and Giovanni Borelli, an Italian physiologist and physicist. Each relied on his personal expertise to theorize on the organization and control of movements. The 18th and early 19th centuries saw work on both the central and peripheral control of movement: the former most notably by Johann Unzer, Marie Jean-Pierre Flourens and Julien-Jean-César Legallois, and the latter by Unzer, Jirí Procháska and many others. Next in the 19th century, neurologists used human locomotion as a precise tool for characterizing motor pathologies: e.g., Guillaume Duchenne de Boulogne's description of locomotor ataxia. Jean-Martin Charcot considered motor control to be organized at two levels of the central nervous system: the cerebral cortex and the spinal cord. Maurice Philippson's defined the dog's step cycle and considered that locomotion used both central and reflex mechanisms. Charles Sherrington explained that locomotor control was usually thought to consist of a succession of peripheral reflexes (e.g., the stepping reflexes). Thomas Graham Brown's then contemporary evidence for the spinal origin of locomotor rhythmicity languished in obscurity until the early 1960s. By then the stage was set for an international assault on the neural control of locomotion, which featured research conducted on both invertebrate and vertebrate animal models. These contributions have progressively became more integrated and interactive, with current work emphasizing that locomotor control involves a seamless integration between central locomotor networks and peripheral feedback.

  19. Functions of Intermittent Locomotion in Mustached Tamarins (Saguinus mystax)

    PubMed Central

    Heymann, Eckhard W.

    2010-01-01

    Many animals interrupt their moving with brief pauses, which appear to serve several different functions. We examined the function of such intermittent locomotion in wild living mustached tamarins (Saguinus mystax), small arboreal New World primates that form mixed-species groups with saddleback tamarins (Saguinus fuscicollis). We investigated how different environmental and social factors affect pausing during locomotion and used these data to infer the function of this behavior. As measures of intermittent locomotion, we used percentage of time spent pausing and pause rate. We considered 3 possible functions that are not mutually exclusive: increased endurance, route planning, and antipredator vigilance. Mustached tamarins spent on average (mean ± SE) 55.1 ± 1.0% of time pausing, which makes effective resource exploitation more time consuming and needs to be outweighed by correspondingly large benefits. Percentage of time spent pausing decreased in larger mixed-species groups vs. smaller mixed-species groups and decreased with height and in monkeys carrying infants. It was not affected by sex, age, spatial arrangement, or single-species group size. Pause rate increased in individuals traveling independently compared to those traveling in file, but was not affected by other factors. The group size effect in mixed-species groups lends support to the notion that pausing during locomotion is an antipredator tactic that can be reduced in the increased safety of larger groups, but other results suggest that additional functions, particularly route planning, are also of great importance. Benefits in terms of predator confusion and group movement coordination are also likely to play a role and remain a topic for further research. PMID:20949115

  20. Sustained periodic terrestrial locomotion in air-breathing fishes.

    PubMed

    Pace, C M; Gibb, A C

    2014-03-01

    While emergent behaviours have long been reported for air-breathing osteichthyians, only recently have researchers undertaken quantitative analyses of terrestrial locomotion. This review summarizes studies of sustained periodic terrestrial movements by air-breathing fishes and quantifies the contributions of the paired appendages and the axial body to forward propulsion. Elongate fishes with axial-based locomotion, e.g. the ropefish Erpetoichthys calabaricus, generate an anterior-to-posterior wave of undulation that travels down the axial musculoskeletal system and pushes the body against the substratum at multiple points. In contrast, appendage-based locomotors, e.g. the barred mudskipper Periophthalmus argentilineatus, produce no axial bending during sustained locomotion, but instead use repeated protraction-retraction cycles of the pectoral fins to elevate the centre of mass and propel the entire body anteriorly. Fishes that use an axial-appendage-based mechanism, e.g. walking catfishes Clarias spp., produce side-to-side, whole-body bending in co-ordination with protraction-retraction cycles of the pectoral fins. Once the body is maximally bent to one side, the tail is pressed against the substratum and drawn back through the mid-sagittal plane, which elevates the centre of mass and rotates it about a fulcrum formed by the pectoral fin and the ground. Although appendage-based terrestrial locomotion appears to be rare in osteichthyians, many different species appear to have converged upon functionally similar axial-based and axial-appendage-based movements. Based on common forms observed across divergent taxa, it appears that dorsoventral compression of the body, elongation of the axial skeleton or the presence of robust pectoral fins can facilitate effective terrestrial movement by air-breathing fishes.

  1. Visual Exploration during Locomotion Limited by Fear of Heights

    PubMed Central

    Kugler, Günter; Huppert, Doreen; Eckl, Maria; Schneider, Erich; Brandt, Thomas

    2014-01-01

    Background Visual exploration of the surroundings during locomotion at heights has not yet been investigated in subjects suffering from fear of heights. Methods Eye and head movements were recorded separately in 16 subjects susceptible to fear of heights and in 16 non-susceptible controls while walking on an emergency escape balcony 20 meters above ground level. Participants wore mobile infrared eye-tracking goggles with a head-fixed scene camera and integrated 6-degrees-of-freedom inertial sensors for recording head movements. Video recordings of the subjects were simultaneously made to correlate gaze and gait behavior. Results Susceptibles exhibited a limited visual exploration of the surroundings, particularly the depth. Head movements were significantly reduced in all three planes (yaw, pitch, and roll) with less vertical head oscillations, whereas total eye movements (saccade amplitudes, frequencies, fixation durations) did not differ from those of controls. However, there was an anisotropy, with a preference for the vertical as opposed to the horizontal direction of saccades. Comparison of eye and head movement histograms and the resulting gaze-in-space revealed a smaller total area of visual exploration, which was mainly directed straight ahead and covered vertically an area from the horizon to the ground in front of the feet. This gaze behavior was associated with a slow, cautious gait. Conclusions The visual exploration of the surroundings by susceptibles to fear of heights differs during locomotion at heights from the earlier investigated behavior of standing still and looking from a balcony. During locomotion, anisotropy of gaze-in-space shows a preference for the vertical as opposed to the horizontal direction during stance. Avoiding looking into the abyss may reduce anxiety in both conditions; exploration of the “vertical strip” in the heading direction is beneficial for visual control of balance and avoidance of obstacles during locomotion. PMID

  2. Exposure to diesel exhaust emissions on board locomotives.

    PubMed

    Seshagiri, Baily

    2003-01-01

    Measurements of diesel exhaust emissions (DEEs) were taken in the cabs of leading and trailing locomotives on 48 runs, under winter and summer conditions, on 9 different routes. The cab windows were kept open during the summer runs and closed during the winter runs. The average measurement duration was 9.5 hours. There was virtually no exposure to DEEs in the lead locomotives during winter or summer and very little in the trailing locomotives during winter. The average elemental carbon (EC) concentration in the trailing units of the summer trials was greater than or equal to the proposed American Conference of Governmental Industrial Hygienists' threshold limit value/time-weighted average of 20 microg/m(3) on 26% of the runs, and was greater than or equal to 10 microg/m(3) on 63%. The concentrations of the gaseous components (nitric oxide, nitrogen dioxide, and carbon monoxide) were from 10 to 20 times below their respective threshold limit values. Mean EC concentration was 2.9 microg/m(3) (detection limit 2 microg/m(3)) during the winter runs and 17.1 microg/m(3) during summer. DEEs appeared to be fairly uniformly distributed in the trailing cabs. Configuration of the locomotives had a major impact on EC concentration, with the mean concentration being nearly three times higher in the forward-backward mode than in the forward-forward mode. Descriptive statistics such as means, medians, standard deviations, and so forth, are provided. Various types of statistical comparisons are reported. Recommendations for controlling exposure are made.

  3. A scattering approach for locomotion on heterogeneous granular media

    NASA Astrophysics Data System (ADS)

    Zhang, Tingnan; Qian, Feifei; Kamor, Adam; Cvitanovic, Predrag; Goldman, Daniel

    2014-03-01

    Locomotion on homogeneous particulate media has been recently studied using biological and robotic experiment and modeled using multi-particle discrete element simulation and empirical resistive force theory. Little is known about how locomotion is affected when environments are composed of particles with a large distribution of sizes. We study in experiment and a reduced order model, locomotion dynamics when particle sizes are widely separated. A hexapedal robot (~15 cm, ~100 g) interacts with a single boulder (whose size is comparable to the robot) during runs on a substrate of homogeneous, loosely packed poppy seeds. We vary the perpendicular distance between the center of the boulder and the trajectory of the robot's center of mass (CoM) before collision (the impact parameter), and measure the post-collision direction. For fixed impact parameter, the CoM deflection sensitively depends on the boulder contact point and leg phase. Counterintuitively, the interactions are largely attractive; the robot turns towards the scattering center. To understand the long-time dynamics, in a reduced-order model, we treat the scattering angle as a function of only the impact parameter with other effects modeled as noise; we thereby extend the study to an infinite field of boulders. This work is supported by DARPA.

  4. Using a robot to study the evolution of legged locomotion

    NASA Astrophysics Data System (ADS)

    McInroe, Benjamin; Astley, Henry; Goldman, Daniel I.

    2014-03-01

    Throughout history, many organisms have used flipper-like limbs for both aquatic and terrestrial locomotion. Modern examples include mudskippers and sea turtles; extinct examples include walkers such as the early tetrapodIchthyostega. In the transition from an aquatic to a terrestrial environment, early walkers had to adapt to the challenges of locomotion over flowable media like sand and mud. Previously, we discovered that a flipper with an elbow-like joint that could passively flex and extend toward and away from the body aided crawling on dry granular media [Mazouchova et. al. 2013], a result related to the jamming of material behind and beneath the flipper. To gain insight into how an additional degree of freedom of this joint affects flipper-based locomotors, we have built a robotic model with limb-joint morphology inspired by Ichthyostega. We add to our previous limb design a passive degree of freedom that allows for supination/pronation of the flipper about a variable insertion angle. Springs at the joints restore the flippers to equilibrium positions after interaction with the media. We study the crutching locomotion of the robot performing a symmetric gait, varying flipper-joint degrees of freedom and limb cycle frequency. This work was supported by NSF PoLS.

  5. Sensitization of locomotion following repeated ventral tegmental injections of cytisine.

    PubMed

    Museo, E; Wise, R A

    1994-06-01

    Systemic injections of nicotine increase locomotion, and repeating these injections brings about a sensitization of the locomotor response. Ventral tegmental injections of the nicotinic agonist cytisine also increase locomotion. In the present study cytisine was administered repeatedly into the ventral tegmentum to determine whether sensitization of its locomotor-activating effects would develop. Four groups of animals were tested; each group received a total of six injections at a rate of one injection every 48 h. Two of these groups received injections of cytisine (10 nmol/side): one group received injections into the ventral tegmentum, and, to insure the anatomical specificity of the locomotor effect, a second group received injections dorsal to the ventral tegmentum. The remaining two groups received vehicle injections: one group received injections into the ventral tegmentum, and the other received injections into more dorsal sites. The group of animals that received injections of cytisine into the ventral tegmentum locomoted more than any other group. In addition, only with this group was a progressive increase in the locomotor response evident across test days. These findings raise the possibility that a neural substrate in the ventral tegmentum mediates the locomotor-activating and sensitizing effects associated with the systemic administration of nicotine.

  6. Central Pattern Generator for Locomotion: Anatomical, Physiological, and Pathophysiological Considerations

    PubMed Central

    Guertin, Pierre A.

    2013-01-01

    This article provides a perspective on major innovations over the past century in research on the spinal cord and, specifically, on specialized spinal circuits involved in the control of rhythmic locomotor pattern generation and modulation. Pioneers such as Charles Sherrington and Thomas Graham Brown have conducted experiments in the early twentieth century that changed our views of the neural control of locomotion. Their seminal work supported subsequently by several decades of evidence has led to the conclusion that walking, flying, and swimming are largely controlled by a network of spinal neurons generally referred to as the central pattern generator (CPG) for locomotion. It has been subsequently demonstrated across all vertebrate species examined, from lampreys to humans, that this CPG is capable, under some conditions, to self-produce, even in absence of descending or peripheral inputs, basic rhythmic, and coordinated locomotor movements. Recent evidence suggests, in turn, that plasticity changes of some CPG elements may contribute to the development of specific pathophysiological conditions associated with impaired locomotion or spontaneous locomotor-like movements. This article constitutes a comprehensive review summarizing key findings on the CPG as well as on its potential role in Restless Leg Syndrome, Periodic Leg Movement, and Alternating Leg Muscle Activation. Special attention will be paid to the role of the CPG in a recently identified, and uniquely different neurological disorder, called the Uner Tan Syndrome. PMID:23403923

  7. Breathing and locomotion in patients with Parkinson's disease.

    PubMed

    Schiermeier, S; Schäfer, D; Schäfer, T; Greulich, W; Schläfke, M E

    2001-10-01

    The phase relationship between respiration and locomotion was examined in ten patients with Parkinson's disease (PD, mean age 65, range 51-79 years) and in six healthy subjects (mean age 63, range 58-68 years). Locomotion was measured by means of pressure sensors attached below the subjects' feet. Respiration was measured using respiratory inductive plethysmography. The data were recorded with a battery-driven portable device. We determined the coordination degree as the portion of steps which occurred within 12/50 bins of the respiratory cycle. The mean degree of coordination of PD patients was 45.0%+/-11.9%, for the healthy subjects 85.1%+/-10.8% (P<0.001). Three healthy subjects showed a 2:1 ratio between step and breathing rate, three a 3:2 ratio. Two PD patients showed a coordination of 4:1 and 3:1, respectively, with a larger scatter than in controls. In the other eight patients steps were almost equally distributed over the entire respiratory cycle. We conclude that in patients with PD the coordination between locomotion and breathing is reduced.

  8. Instability-based mechanism for body undulations in centipede locomotion.

    PubMed

    Aoi, Shinya; Egi, Yoshimasa; Tsuchiya, Kazuo

    2013-01-01

    Centipedes have many body segments and legs and they generate body undulations during terrestrial locomotion. Centipede locomotion has the characteristic that body undulations are absent at low speeds but appear at faster speeds; furthermore, their amplitude and wavelength increase with increasing speed. There are conflicting reports regarding whether the muscles along the body axis resist or support these body undulations and the underlying mechanisms responsible for the body undulations remain largely unclear. In the present study, we investigated centipede locomotion dynamics using computer simulation with a body-mechanical model and experiment with a centipede-like robot and then conducted dynamic analysis with a simple model to clarify the mechanism. The results reveal that body undulations in these models occur due to an instability caused by a supercritical Hopf bifurcation. We subsequently compared these results with data obtained using actual centipedes. The model and actual centipedes exhibit similar dynamic properties, despite centipedes being complex, nonlinear dynamic systems. Based on our findings, we propose a possible passive mechanism for body undulations in centipedes, similar to a follower force or jackknife instability. We also discuss the roles of the muscles along the body axis in generating body undulations in terms of our physical model.

  9. Instability-based mechanism for body undulations in centipede locomotion

    NASA Astrophysics Data System (ADS)

    Aoi, Shinya; Egi, Yoshimasa; Tsuchiya, Kazuo

    2013-01-01

    Centipedes have many body segments and legs and they generate body undulations during terrestrial locomotion. Centipede locomotion has the characteristic that body undulations are absent at low speeds but appear at faster speeds; furthermore, their amplitude and wavelength increase with increasing speed. There are conflicting reports regarding whether the muscles along the body axis resist or support these body undulations and the underlying mechanisms responsible for the body undulations remain largely unclear. In the present study, we investigated centipede locomotion dynamics using computer simulation with a body-mechanical model and experiment with a centipede-like robot and then conducted dynamic analysis with a simple model to clarify the mechanism. The results reveal that body undulations in these models occur due to an instability caused by a supercritical Hopf bifurcation. We subsequently compared these results with data obtained using actual centipedes. The model and actual centipedes exhibit similar dynamic properties, despite centipedes being complex, nonlinear dynamic systems. Based on our findings, we propose a possible passive mechanism for body undulations in centipedes, similar to a follower force or jackknife instability. We also discuss the roles of the muscles along the body axis in generating body undulations in terms of our physical model.

  10. Posterior hypothalamic nucleus deep brain stimulation restores locomotion in rats with haloperidol-induced akinesia but not skilled forelimb use in pellet reaching and lever pressing.

    PubMed

    Young, C K; Whishaw, I Q; Bland, B H

    2011-09-29

    Recent studies have shown that electrical stimulation of the posterior hypothalamic nucleus (PH) facilitates locomotion in control rats, and rats were made akinetic by dopaminergic blockade via haloperidol or dopamine depletion by the neurotoxin 6-hydroxydopamine. These findings suggest that PH stimulation might be a promising treatment for akinesia associated with dopamine loss in Parkinson's disease. The present study further examined the positive effects of PH stimulation on behavior by characterizing its potential facilitatory effects on tasks that require skilled movements. Rats were trained to reach for food pellets with a forelimb (skilled reaching) or press a bar in an operant conditioning task for food. PH stimulation in undrugged rats not only facilitated locomotion in each of the tasks, but also impaired performance of the skilled movement components of the tasks. Haloperidol reduced locomotion and skilled movement, and PH stimulation only restored locomotion. The results are discussed in relation to the idea that PH stimulation selectively facilitates locomotor behavior and may have limited use in restoring impairments in skilled movements and consummatory behavior that results from dopaminergic depletion.

  11. Locomotion training of legged robots using hybrid machine learning techniques

    NASA Technical Reports Server (NTRS)

    Simon, William E.; Doerschuk, Peggy I.; Zhang, Wen-Ran; Li, Andrew L.

    1995-01-01

    In this study artificial neural networks and fuzzy logic are used to control the jumping behavior of a three-link uniped robot. The biped locomotion control problem is an increment of the uniped locomotion control. Study of legged locomotion dynamics indicates that a hierarchical controller is required to control the behavior of a legged robot. A structured control strategy is suggested which includes navigator, motion planner, biped coordinator and uniped controllers. A three-link uniped robot simulation is developed to be used as the plant. Neurocontrollers were trained both online and offline. In the case of on-line training, a reinforcement learning technique was used to train the neurocontroller to make the robot jump to a specified height. After several hundred iterations of training, the plant output achieved an accuracy of 7.4%. However, when jump distance and body angular momentum were also included in the control objectives, training time became impractically long. In the case of off-line training, a three-layered backpropagation (BP) network was first used with three inputs, three outputs and 15 to 40 hidden nodes. Pre-generated data were presented to the network with a learning rate as low as 0.003 in order to reach convergence. The low learning rate required for convergence resulted in a very slow training process which took weeks to learn 460 examples. After training, performance of the neurocontroller was rather poor. Consequently, the BP network was replaced by a Cerebeller Model Articulation Controller (CMAC) network. Subsequent experiments described in this document show that the CMAC network is more suitable to the solution of uniped locomotion control problems in terms of both learning efficiency and performance. A new approach is introduced in this report, viz., a self-organizing multiagent cerebeller model for fuzzy-neural control of uniped locomotion is suggested to improve training efficiency. This is currently being evaluated for a possible

  12. Association of Mode of Locomotion and Independence in Locomotion With Long-Term Outcomes After Spinal Cord Injury

    PubMed Central

    Krause, James; Carter, Rickey E; Brotherton, Sandra

    2009-01-01

    Background/Objective: To explore the association of mode of locomotion (ambulation vs wheelchair use) and independence in locomotion (independent vs require assistance) with health, participation, and subjective well-being (SWB) after spinal cord injury (SCI). Research Design: Secondary analysis was conducted on survey data collected from 2 rehabilitation hospitals in the Midwest and a specialty hospital in the southeastern United States. The 1,493 participants were a minimum of 18 years of age and had traumatic SCI of at least 1 year duration at enrollment. Main Outcome Measures: Three sets of outcome measures were used: SWB, participation, and health. SWB was measured by 8 scales and a measure of depressive symptoms, participation by 3 items, health by general health ratings, days in poor health, hospitalizations, and treatments. Results: Small but significant associations were observed between independence in locomotion and every outcome. Ambulation was associated with greater participation but a mixed pattern of favorable and unfavorable health and SWB outcomes. Supplemental analyses were conducted on those who ambulated but who were dependent on others to do so (n = 117), because this group reported poor outcomes in several areas. Individuals who were independent in wheelchair use reported substantially better outcomes than nonwheelchair users and those dependent on others in wheelchair use. Conclusions: Although ambulation is often a recovery goal, individuals with SCI who ambulate do not uniformly report better outcomes than wheelchair users, and those who depend on others for assistance with ambulation may experience a unique set of problems. PMID:19810625

  13. Behavioural toxicity assessment of silver ions and nanoparticles on zebrafish using a locomotion profiling approach.

    PubMed

    Ašmonaitė, Giedrė; Boyer, Scott; Souza, Karine Bresolin de; Wassmur, Britt; Sturve, Joachim

    2016-04-01

    Zebrafish (Danio rerio) is not only a widely used species in the Fish Embryo Toxicity (FET) test but also an emerging model in behavioural ecotoxicology. By using automatic behaviour tracking technology, locomotion of developing zebrafish (ZF) larvae can be accurately recorded and potentially used in an ecotoxicological context to detect toxicant-induced behavioural alterations. In this study, we explored if and how quantitative locomotion data can be used for sub-lethal toxicity testing within the FET framework. We exposed ZF embryos to silver ions and nanoparticles, which previously have been reported to cause neurodevelopmental toxicity and behavioural retardation in early-life stages of ZF. Exposure to a broad range of silver (Ag(+) and AgNPs) concentrations was conducted, and developmental toxicity was assessed using FET criteria. For behavioural toxicity assessment, locomotion of exposed ZF eleutheroembryos (120hpf) was quantified according to a customised behavioural assay in an automatic video tracking system. A set of repeated episodes of dark/light stimulation were used to artificially stress ZF and evoke photo-motor responses, which were consequently utilized for locomotion profiling. Our locomotion-based behaviour profiling approach consisted of (1) dose-response ranking for multiple and single locomotion variables; (2) quantitative assessment of locomotion structure; and (3) analysis of ZF responsiveness to darkness stimulation. We documented that both silver forms caused adverse effects on development and inhibited hatchability and, most importantly, altered locomotion. High Ag(+) and AgNPs exposures significantly suppressed locomotion and a clear shift in locomotion towards inactivity was reported. Additionally, we noted that low, environmentally relevant Ag(+) concentrations may cause subordinate locomotive changes (hyperactivity) in developing fish. Overall, it was concluded that our locomotion-based behaviour-testing scheme can be used jointly

  14. A survey report for the design of biped locomotion robot: The WL-12 (Waseda Leg-12)

    NASA Astrophysics Data System (ADS)

    Takanishi, Atsuo; Kato, Ichiro; Kume, Etsuo

    1991-11-01

    A mechanical design study of biped locomotion robots is going on at JAERI within the scope of the Human Acts Simulation Program (HASP). The design study at JAERI is of an arbitrarily mobile robot for inspection of nuclear facilities. A survey has been performed for collecting useful information from already existing biped locomotion robots. This is a survey report of the biped locomotion robot: the WL-12 designed and developed at Waseda University. This report includes the mechanical model and control system designs.

  15. On designing geometric motion planners to solve regulating and trajectory tracking problems for robotic locomotion systems.

    PubMed

    Asnafi, Alireza; Mahzoon, Mojtaba

    2011-09-01

    Based on a geometric fiber bundle structure, a generalized method to solve both regulation and trajectory tracking problems for locomotion systems is presented. The method is especially applied to two case studies of robotic locomotion systems; a three link articulated fish-like robot as a prototype of locomotion systems with symmetry, and the snakeboard as a prototype of mixed locomotion systems. Our results show that although these motion planners have an open loop structure, due to their generalities, they can steer case studies with negligible errors for almost any complicated path.

  16. Benefit of "Push-pull" Locomotion for Planetary Rover Mobility

    NASA Technical Reports Server (NTRS)

    Creager, Colin M.; Moreland, Scott Jared; Skonieczny, K.; Johnson, K.; Asnani, V.; Gilligan, R.

    2011-01-01

    As NASAs exploration missions on planetary terrains become more aggressive, a focus on alternative modes of locomotion for rovers is necessary. In addition to climbing steep slopes, the terrain in these extreme environments is often unknown and can be extremely hard to traverse, increasing the likelihood of a vehicle or robot becoming damaged or immobilized. The conventional driving mode in which all wheels are either driven or free-rolling is very efficient on flat hard ground, but does not always provide enough traction to propel the vehicle through soft or steep terrain. This paper presents an alternative mode of travel and investigates the fundamental differences between these locomotion modes. The methods of push-pull locomotion discussed can be used with articulated wheeled vehicles and are identified as walking or inchinginch-worming. In both cases, the braked non-rolling wheels provide increased thrust. An in-depth study of how soil reacts under a rolling wheel vs. a braked wheel was performed by visually observing the motion of particles beneath the surface. This novel technique consists of driving or dragging a wheel in a soil bin against a transparent wall while high resolution, high-rate photographs are taken. Optical flow software was then used to determine shearing patterns in the soil. Different failure modes were observed for the rolling and braked wheel cases. A quantitative comparison of inching vs. conventional driving was also performed on a full-scale vehicle through a series of drawbar pull tests in the Lunar terrain strength simulant, GRC-1. The effect of tire stiffness was also compared; typically compliant tires provide better traction when driving in soft soil, however its been observed that rigid wheels may provide better thrust when non-rolling. Initial tests indicate up to a possible 40 increase in pull force capability at high slip when inching vs. rolling.

  17. Sexuality of Disabled Athletes Depending on the Form of Locomotion

    PubMed Central

    Plinta, Ryszard; Sobiecka, Joanna; Drosdzol-Cop, Agnieszka; Nowak-Brzezińska, Agnieszka; Skrzypulec-Plinta, Violetta

    2015-01-01

    The main purpose of this study was to determine sexuality of disabled athletes depending on the form of locomotion. The study included 170 disabled athletes, aged between 18 and 45. The entire population was divided into 3 research groups depending on the form of locomotion: moving on wheelchairs (n=52), on crutches (n=29) and unaided (n=89). The research tool was a questionnaire voluntarily and anonymously completed by the respondents of the research groups. The questionnaire was composed of a general part concerning the socio-demographic conditions, medical history, health problems, a part dedicated to physical disability as well as the Polish version of the International Index of Erectile Function (IIEF) and the Female Sexual Function Index (FSFI) evaluating sexual life. STATISTICA 10.0 for Windows was used in the statistical analysis. Subjects moving on crutches were significantly older than ones moving on wheelchairs and unaided (34.41 ±11.00 vs. 30.49 ±10.44 and 27.99 ±10.51 years, respectively) (p=0.018). Clinically significant erectile dysfunctions were most often diagnosed in athletes moving on wheelchairs (70.27%), followed by athletes moving on crutches and moving unaided (60% and 35.42%, respectively; p=0.048). Clinical sexual dysfunctions were diagnosed on a similar level among all female athletes. It was concluded that the form of locomotion may determine sexuality of disabled men. Males on wheelchair revealed the worst sexual functioning. Female athletes moving on wheelchairs, on crutches and moving unaided were comparable in the aspect of their sexual life. PMID:26834876

  18. Comparative energetics of mammalian locomotion: humans are not different.

    PubMed

    Halsey, L G; White, C R

    2012-11-01

    Debates about the evolution of human bipedality sometimes include discussion on the energy costs of terrestrial locomotion of extinct and extant hominins. However, comparative analyses of hominin transport costs conducted to date have been limited and potentially misinforming, in part because they fail to consider phylogenetic history. In the present study, we compare the measured costs of pedestrian locomotion in humans and the estimated costs for Australopithecus afarensis (an early bipedal hominin), to a database of locomotory costs for mammals. Using data for 81 species of mammal, we demonstrate significant phylogenetic signal in both log-transformed body mass (logMass) and log-transformed net cost of transport (logNCOT), but no phylogenetic signal in residuals of the relationship between logNCOT and logMass. We then used this relationship to generate a prediction line for NCOT based on body mass, and compared this prediction with published measured data for NCOT of running and walking in humans, and estimated NCOT of walking in A. afarensis. The cost of human walking was 25% lower than predicted, while the cost of running was 27% higher. The cost of A. afarensis walking was 32% lower than predicted. However, all of these data points fall within the 95% prediction interval for mammals, indicating that they are not significantly lower or higher than predicted for other mammals of similar mass. Moreover, the difference between humans and our closest living relative the common chimpanzee is comparable to differences between other similarly closely related species. We therefore conclude that there is no evidence from metabolic data that humans, or A. afarensis, have/had a reduced energy cost of pedestrian locomotion compared to other mammals in general.

  19. Locomotion by tangential deformation in a polymeric fluid

    NASA Astrophysics Data System (ADS)

    Zhu, Lailai; Do-Quang, Minh; Lauga, Eric; Brandt, Luca

    2011-01-01

    In several biologically relevant situations, cell locomotion occurs in polymeric fluids with Weissenberg number larger than 1. Here we present results of three-dimensional numerical simulations for the steady locomotion of a self-propelled body in a model polymeric (Giesekus) fluid at low Reynolds number. Locomotion is driven by steady tangential deformation at the surface of the body (the so-called squirming motion). In the case of a spherical squirmer, we show that the swimming velocity is systematically less than that in a Newtonian fluid, with a minimum occurring for Weissenberg numbers of order 1. The rate of work done by the swimmer always goes up compared to that occurring in the Newtonian solvent alone but is always lower than the power necessary to swim in a Newtonian fluid with the same viscosity. The swimming efficiency, defined as the ratio between the rate of work necessary to pull the body at the swimming speed in the same fluid and the rate of work done by swimming, is found to always be increased in a polymeric fluid. Further analysis reveals that polymeric stresses break the Newtonian front-back symmetry in the flow profile around the body. In particular, a strong negative elastic wake is present behind the swimmer, which correlates with strong polymer stretching, and its intensity increases with Weissenberg number and viscosity contrasts. The velocity induced by the squirmer is found to decay in space faster than in a Newtonian flow, with a strong dependence on the polymer relaxation time and viscosity. Our computational results are also extended to prolate spheroidal swimmers and smaller polymer stretching are obtained for slender shapes compared to bluff swimmers. The swimmer with an aspect ratio of two is found to be the most hydrodynamically efficient.

  20. Support afferentation in the posture and locomotion control system

    NASA Astrophysics Data System (ADS)

    Grigoriev, Anatoly; Tomilovskaya, Elena; Kozlovskaya, Inesa

    Mechanisms of support afferentation contribution in posture and locomotion control, which were uncertain up to now, became the point of intensive studies recently. This became possible since the space flights era started which created the conditions for simulated microgravity experiments under conditions of dry immersion and bedrest. The results of neurophysiological studies performed under the conditions of supportlessness have shown that decline or elimination of support loads is followed by deep and fast developing alterations in postural tonic system, including development of postural muscle atonia, changes of recruitment order of motoneurons innervating the shin muscles, spinal hyperreflexia development etc. (Kozlovskaya I.B. et al., 1987). It has been also shown that application of artificial support stimulation in the regimen of natural locomotion under these conditions decreases significantly or even eliminates the development of mentioned changes. The results of these studies laid down the basis for a new hypothesis on the trigger role of support afferentation in postural tonic system and its role in organization and control of postural synergies (Grigoriev A.I. et al., 2004). According to this hypothesis the muscle reception is considered to be the leading afferent input in the control of locomotion. However the data of recent studies pointed out strongly to the participation of support afferentation in definition of cognitive strategies and motor programs of locomotor movements (Chernikova L.A. et al., 2013) and, consequently, in the processes of their initiation (Gerasimenko Yu.P. et al., 2012). The cortical locomotor reflex composes apparently the basis of these processes. The receptive field of this reflex is located in the support zones of the soles and the central part is located in the posterior parietal areas (IPL) of brain cortex. The study is supported by RFBR grant N 13-04-12091 OFI-m.

  1. Emulating constant acceleration locomotion mechanics on a treadmill.

    PubMed

    Farris, Dominic James

    2016-03-21

    Locomotion on an accelerating treadmill belt is not dynamically similar to overground acceleration. The purpose of this study was to test if providing an external force to compensate for inertial forces during locomotion on an accelerating treadmill belt could induce locomotor dynamics similar to real accelerations. Nine males (mean±sd age=26±4 years, mass=81±9kg, height=1.8±0.05m) began walking and transitioned to running on an accelerating instrumented treadmill belt at three accelerations (0.27ms(-2), 0.42ms(-2), 0.76ms(-2)). Half the trials were typical treadmill locomotion (TT) and half were emulated acceleration (EA), where elastic tubing harnessed to the participant provided a horizontal force equal to mass multiplied by acceleration. Net mechanical work (WCOM) and ground reaction force impulses (IGRF) were calculated for individual steps and a linear regression was performed with these experimental measures as independent variables and theoretically derived values of work and impulse as predictor variables. For EA, linear fits were significant for WCOM (y=1.19x+10.5, P<0.001, R(2)=0.41) and IGRF (y=0.95x+8.1, P<0.001, R(2)=0.3). For TT, linear fits were not significant and explained virtually no variance for WCOM (y=0.06x+1.6, P=0.29, R(2)<0.01) and IGRF (y=0.10x+0.4, P=0.06, R(2)=0.01). This suggested that the EA condition was a better representation of real acceleration dynamics than TT. Running steps from EA where work and impulse closely matched theoretical values showed similar adaptations to increasing acceleration as have been previously observed overground (forward reorientation of GRF vector without an increase in magnitude or change in spatio-temporal metrics).

  2. Locomotion speed of the benthic foraminifer Ammonia tepida exposed to different nitrogen and carbon sources

    NASA Astrophysics Data System (ADS)

    Jauffrais, Thierry; Jesus, Bruno; Geslin, Emmanuelle; Briand, Floriane; Jézéquel, Véronique Martin

    2016-12-01

    Ammonia tepida is a dominant benthic foraminifer colonizing intertidal mudflat sediments. Horizontal locomotion speeds were monitored using time-lapse image analysis over 6 and 24 h. Experimental conditions were based on foraminifera exposed to dry sediment re-suspended in artificial sea water (ASW) without any nutrient addition (condition DS), to combusted sediment re-suspended in in ASW also without any nutrient addition (condition CS), or to combusted sediment re-suspended in ASW enriched with either: nitrate, urea, glucose, soil extract (SE), extracellular polymeric substances (EPS), benthic diatoms (Entomoneis paludosa) or natural microphytobenthic assemblages (MPB). Significant differences were already measured after 6 h between A. tepida mean locomotion speeds at the different experimental conditions. However, differences were clearer after 24 h where the slowest A. tepida mean locomotion speed was measured in specimens placed in CS (1.00 ± 0.30 mm h- 1) and the highest mean locomotion speed in DS (2.99 ± 0.22 mm h- 1). Three different groups were defined according to their locomotion speed, (1) foraminifera exposed to DS had a locomotion speed significantly higher than all other conditions, (2) foraminifera placed in conditions enriched in SE, Glucose, Urea and EPS had intermediary locomotion speeds (1.8-2.5 mm h- 1), and (3) conditions with foraminifera showing the lowest locomotion speeds (1-1.6 mm h- 1) were CS, nitrate, MPB and E. paludosa. Thus, foraminifera exposed to organic matter (DS, SE, Glucose and Urea) showed faster locomotion speeds than foraminifera exposed to inorganic matter (CS, nitrate) or live preys (E. paludosa, MPB). Dissolved organic matter enrichment enhanced foraminifera locomotion speed, which might be a behavioural response to satisfy their carbon and/or nitrogen requirements, and the lowest locomotion speed observed when feeding on live preys might be a consequence of longer time required for live prey phagocytosis.

  3. Scaling in Theropod Dinosaurs: Femoral Bone Strength and Locomotion

    NASA Astrophysics Data System (ADS)

    Lee, Scott

    2015-02-01

    In our first article1 on scaling in theropod dinosaurs, the longitudinal stress in the leg bones due to supporting the weight of the animal was studied and found not to control the dimensions of the femur. As a continuation of our study of elasticity in dinosaur bones, we now examine the transverse stress in the femur due to locomotion and find that this effect is important for the geometry of the bone. We find that larger theropods (including Tyrannosaurus rex) were less athletic than smaller theropods.

  4. Locomotion and visually guided behavior in salamander: a neuromechanical study

    NASA Astrophysics Data System (ADS)

    Ijspeert, Auke J.; Arbib, Michael A.

    2000-10-01

    This article investigates the neural mechanisms underlying locomotion and visually-guided behavior in a lower vertebrate: the salamander. We develop connectionist models of the salamander's locomotor circuitry and visual system, and analyze their functioning by embedding them into a biomechanical simulation of the salamander's body. This work is therefore an experiment in computational neuroethology which aims at investigating how behavior results from the coupling of a central nervous system (CNS) and a body, and from the interactions of the CNS-body pair with the environment. We believe that understanding these mechanisms is not only relevant for neurobiology but also for potential applications in robotics.

  5. Improvement of fuel injection system of locomotive diesel engine.

    PubMed

    Li, Minghai; Cui, Hongjiang; Wang, Juan; Guan, Ying

    2009-01-01

    The traditional locomotive diesels are usually designed for the performance of rated condition and much fuel will be consumed. A new plunger piston matching parts of fuel injection pump and injector nozzle matching parts were designed. The experimental results of fuel injection pump test and diesel engine show that the fuel consumption rate can be decreased a lot in the most of the working conditions. The forced lubrication is adopted for the new injector nozzle matching parts, which can reduce failure rate and increase service life. The design has been patented by Chinese State Patent Office.

  6. Biomechanical Analysis of Treadmill Locomotion on the International Space Station

    NASA Technical Reports Server (NTRS)

    De Witt, J. K.; Fincke, R. S.; Guilliams, M. E.; Ploutz-Snyder, L. L.

    2011-01-01

    Treadmill locomotion exercise is an important aspect of ISS exercise countermeasures. It is widely believed that an optimized treadmill exercise protocol could offer benefits to cardiovascular and bone health. If training heart rate is high enough, treadmill exercise is expected to lead to improvements in aerobic fitness. If impact or bone loading forces are high enough, treadmill exercise may be expected to contribute to improved bone outcomes. Ground-based research suggests that joint loads increase with increased running speed. However, it is unknown if increases in locomotion speed results in similar increases in joint loads in microgravity. Although data exist regarding the biomechanics of running and walking in microgravity, a majority were collected during parabolic flight or during investigations utilizing a microgravity analog. The Second Generation Treadmill (T2) has been in use on the International Space Station (ISS) and records the ground reaction forces (GRF) produced by crewmembers during exercise. Biomechanical analyses will aid in understanding potential differences in typical gait motion and allow for modeling of the human body to determine joint and muscle forces during exercise. By understanding these mechanisms, more appropriate exercise prescriptions can be developed that address deficiencies. The objective of this evaluation is to collect biomechanical data from crewmembers during treadmill exercise prior to and during flight. The goal is to determine if locomotive biomechanics differ between normal and microgravity environments and to determine how combinations of subject load and speed influence joint loading during in-flight treadmill exercise. Further, the data will be used to characterize any differences in specific bone and muscle loading during locomotion in these two gravitational conditions. This project maps to the HRP Integrated Research Plan risks including Risk of Bone Fracture (Gap B15), Risk of Early Onset Osteoporosis Due to

  7. Evolution of Patterning Systems and Circuit Elements for Locomotion

    PubMed Central

    Jung, Heekyung; Dasen, Jeremy S.

    2015-01-01

    Summary Evolutionary modifications in nervous systems enabled organisms to adapt to their specific environments and underlie the remarkable diversity of behaviors expressed by animals. Resolving the pathways that shaped and modified neural circuits during evolution remains a significant challenge. Comparative studies have revealed a surprising conservation in the intrinsic signaling systems involved in early patterning of bilaterian nervous systems, but also raise the question of how neural circuit compositions and architectures evolved within specific animal lineages. In this Review we discuss the mechanisms that contributed to the emergence and diversity of animal nervous systems, focusing on the circuits governing vertebrate locomotion. PMID:25710528

  8. Neonatal seizure automatism and human inborn pattern of quadrupedal locomotion.

    PubMed

    Pavlidis, E; Cantalupo, G; Cattani, L; Tassinari, C A; Pisani, F

    2016-09-01

    Seizures in newborns do not always show a clear electro-clinical correlation. The real epileptic nature of some stereotyped rhythmic movements, included in the 'subtle seizures' and considered as brainstem release phenomena, is still debated. We report a brain injured newborn, who displayed several episodes of repetitive limb movements. The ictal EEG discharge, during one of these episodes, was associated with a motor pattern modification, which was endowed with quadrupedal locomotion kinematic features. This might represent an indirect evidence of cervical and lumbar Central Pattern Generators interconnection with in-phase coordination between diagonal limbs since the first hours of life in humans.

  9. Propulsion by sinusoidal locomotion: A motion inspired by Caenorhabditis elegans

    NASA Astrophysics Data System (ADS)

    Ulrich, Xialing

    Sinusoidal locomotion is commonly seen in snakes, fish, nematodes, or even the wings of some birds and insects. This doctoral thesis presents the study of sinusoidal locomotion of the nematode C. elegans in experiments and the application of the state-space airloads theory to the theoretical forces of sinusoidal motion. An original MATLAB program has been developed to analyze the video records of C. elegans' movement in different fluids, including Newtonian and non-Newtonian fluids. The experimental and numerical studies of swimming C. elegans has revealed three conclusions. First, though the amplitude and wavelength are varying with time, the motion of swimming C. elegans can still be viewed as sinusoidal locomotion with slips. The average normalized wavelength is a conserved character of the locomotion for both Newtonian and non-Newtonian fluids. Second, fluid viscosity affects the frequency but not the moving speed of C. elegans, while fluid elasticity affects the moving speed but not the frequency. Third, by the resistive force theory, for more elastic fluids the ratio of resistive coefficients becomes smaller. Inspired by the motion of C. elegans and other animals performing sinusoidal motion, we investigated the sinusoidal motion of a thin flexible wing in theory. Given the equation of the motion, we have derived the closed forms of propulsive force, lift and other generalized forces applying on the wing. We also calculated the power required to perform the motion, the power lost due to the shed vortices and the propulsive efficiency. These forces and powers are given as functions of reduced frequency k, dimensionless wavelength z, dimensionless amplitude A/b, and time. Our results show that a positive, time-averaged propulsive force is produced for all k>k0=pi/ z. At k=k0, which implies the moment when the moving speed of the wing is the same as the wave speed of its undulation, the motion reaches a steady state with all forces being zero. If there were no

  10. Locomotion of an all-terrain mobile robot

    NASA Astrophysics Data System (ADS)

    Iagolnitzer, M.; Richard, F.; Samson, J. F.; Tournassoud, P.

    The authors introduce a framework and prospective solutions for intelligent locomotion, defined as the ability for a mobile robot to cross over obstacles along a path roughly determined either through teleoperation or by a navigation path-finder. Then, they present a simple but efficient control scheme derived from these concepts, taking into account ground clearance, vehicle safety, and possible occlusions in the vision field. This control scheme is applied to Rami, a four tiltable track robot equipped with force sensors, an inertial reference system, a laser-stripe range finder, and extensive real-time computing facilities based on a decentralized architecture.

  11. Ultrasonic manipulation of locomotive microorganisms and evaluation of their activity

    NASA Astrophysics Data System (ADS)

    Saito, Mitsunori; Kitamura, Norio; Terauchi, Masaki

    2002-12-01

    Acoustic manipulation of locomotive microorganisms, i.e., euglena and paramecia, was conducted by using ultrasonic standing waves of ˜3 MHz. Microorganisms were trapped at the intersections of the nodes in the two orthogonal standing waves and were transferred horizontally and vertically by the suitable ultrasonic frequency change. Aggregation of microorganisms was also observed in the process of the cyclic frequency change. The trapping efficiency depended on both ultrasonic power density and the activity of microorganisms. The effects of water temperature and illumination on their activity were evaluated by measuring the ultrasonic trapping efficiency.

  12. The scaling of uphill and downhill locomotion in legged animals.

    PubMed

    Birn-Jeffery, Aleksandra V; Higham, Timothy E

    2014-12-01

    Animals must continually respond dynamically as they move through complex environments, and slopes are a common terrain on which legged animals must move. Despite this, non-level locomotion remains poorly understood. In this study, we first review the literature on locomotor mechanics, metabolic cost, and kinematic strategies on slopes. Using existing literature we then performed scaling analyses of kinematic variables, including speed, duty factor, and stride-length across a range of body sizes from ants to horses. The studies that examined locomotion on inclines vastly outnumbered those focusing on declines. On inclines, animals tend to reduce speed and increase duty factor, but a similar consensus could not be reached for declines. Remarkably, stride-length did not differ between locomotion on inclines and on level terrain, but this may have resulted from data only being available for low slopes (<30°). On declines there appears to be a shift in locomotor strategy that is size-dependent. At masses <1-10 kg, animals tended to use shorter strides than on level terrain, and the opposite occurred at larger body masses. Therefore, possibly due to stability issues, body mass plays a significant role in the locomotor strategy used when traveling downhill. Although we currently lack sufficient data, differential leg function is likely to be critical for locomotion on slopes, with mechanical demands differing on limbs during movement on level, inclined, and declined surfaces. Our scaling analysis not only highlights areas that require future work, but also suggests that body size is important for determining the mechanics and strategies animals use to negotiate non-level terrain. It is clear that selection has resulted in an incredible range of body size among animals, both extant and extinct, and it is likely that the ability to move up and down slopes has constrained or relaxed these mechanical pressures. Given the lack of integration of ecological data with

  13. Application of oxygen-enriched combustion for locomotive diesel engines. Phase 1

    SciTech Connect

    Poola, R.B.; Sekar, R.R.; Assanis, D.N.

    1996-09-01

    A thermodynamic simulation is used to study the effects of oxygen-enriched intake air on the performance and nitrogen oxide (NO) emissions of a locomotive diesel engine. The parasitic power of the air separation membrane required to supply the oxygen-enriched air is also estimated. For a given constraint on peak cylinder pressure, the gross and net power outputs of an engine operating under different levels of oxygen enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in an increase in net engine power of approximately 13% when intake air with an oxygen content of 28% by volume is used and fuel injection timing is retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure improves power by only 4%. If part of the significantly higher exhaust enthalpies available as a result of oxygen enrichment are recovered, the power requirements of the air separator membrane can be met, resulting in substantial net power improvements. Oxygen enrichment reduces particulate and visible smoke emissions but increases NO emissions. However, a combination of retarded fuel injection timing and post-treatment of exhaust gases may be adequate to meet the locomotive diesel engine NO{sub x} standards. Exhaust gas after-treatment and heat recovery would be required to realize the full potential of oxygen enrichment. Economic analysis shows that oxygen-enrichment technology is economically feasible and provides high returns on investment. The study also indicates the strong influence of membrane parasitic requirements and exhaust energy recovery on economic benefits. To obtain an economic advantage while using a membrane with higher parasitic power requirements, it is necessary to recover a part of the exhaust energy.

  14. 19 CFR 123.13 - Foreign repairs to domestic locomotives and other domestic railroad equipment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... domestic railroad equipment. 123.13 Section 123.13 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... International Traffic § 123.13 Foreign repairs to domestic locomotives and other domestic railroad equipment. A report of the first arrival in the United States of a domestic locomotive or other railroad...

  15. 19 CFR 123.13 - Foreign repairs to domestic locomotives and other domestic railroad equipment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... domestic railroad equipment. 123.13 Section 123.13 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... International Traffic § 123.13 Foreign repairs to domestic locomotives and other domestic railroad equipment. A report of the first arrival in the United States of a domestic locomotive or other railroad...

  16. 19 CFR 123.13 - Foreign repairs to domestic locomotives and other domestic railroad equipment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... domestic railroad equipment. 123.13 Section 123.13 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... International Traffic § 123.13 Foreign repairs to domestic locomotives and other domestic railroad equipment. A report of the first arrival in the United States of a domestic locomotive or other railroad...

  17. 49 CFR 229.133 - Interim locomotive conspicuity measures-auxiliary external lights.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Interim locomotive conspicuity measures-auxiliary external lights. 229.133 Section 229.133 Transportation Other Regulations Relating to Transportation... STANDARDS Safety Requirements Cabs and Cab Equipment § 229.133 Interim locomotive conspicuity...

  18. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... boilers. 230.20 Section 230.20 Transportation Other Regulations Relating to Transportation (Continued... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... maintained for the life of the boiler. (See appendix B of this part.) (b) Welded and riveted repairs...

  19. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... boilers. 230.20 Section 230.20 Transportation Other Regulations Relating to Transportation (Continued... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... maintained for the life of the boiler. (See appendix B of this part.) (b) Welded and riveted repairs...

  20. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... boilers. 230.20 Section 230.20 Transportation Other Regulations Relating to Transportation (Continued... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... maintained for the life of the boiler. (See appendix B of this part.) (b) Welded and riveted repairs...

  1. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... boilers. 230.20 Section 230.20 Transportation Other Regulations Relating to Transportation (Continued... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... maintained for the life of the boiler. (See appendix B of this part.) (b) Welded and riveted repairs...

  2. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... boilers. 230.20 Section 230.20 Transportation Other Regulations Relating to Transportation (Continued... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... maintained for the life of the boiler. (See appendix B of this part.) (b) Welded and riveted repairs...

  3. 19 CFR 123.13 - Foreign repairs to domestic locomotives and other domestic railroad equipment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... domestic railroad equipment. 123.13 Section 123.13 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... International Traffic § 123.13 Foreign repairs to domestic locomotives and other domestic railroad equipment. A report of the first arrival in the United States of a domestic locomotive or other railroad...

  4. 19 CFR 123.13 - Foreign repairs to domestic locomotives and other domestic railroad equipment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... domestic railroad equipment. 123.13 Section 123.13 Customs Duties U.S. CUSTOMS AND BORDER PROTECTION... International Traffic § 123.13 Foreign repairs to domestic locomotives and other domestic railroad equipment. A report of the first arrival in the United States of a domestic locomotive or other railroad...

  5. 49 CFR Appendix E to Part 229 - Performance Criteria for Locomotive Crashworthiness

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... length; 65,000 pound minimum weight; and uniform density. The longitudinal axis of the proxy object must be oriented horizontally perpendicular to the longitudinal axis of the locomotive. (3) Impact and... resulting in no more than 24 inches of crush along the longitudinal axis of the locomotive, measured...

  6. 49 CFR 1242.25 - Locomotive servicing facilities (account XX-19-27).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Locomotive servicing facilities (account XX-19-27). 1242.25 Section 1242.25 Transportation Other Regulations Relating to Transportation (Continued) SURFACE... Structures § 1242.25 Locomotive servicing facilities (account XX-19-27). Separate common expenses...

  7. Differential gating of thalamo-cortical signals by reticular nucleus of thalamus during locomotion

    PubMed Central

    Marlinski, Vladimir; Sirota, Mikhail G.; Beloozerova, Irina N.

    2012-01-01

    SUMMARY The thalamic reticular nucleus (RE) provides inhibition to the dorsal thalamus, and forms a crucial interface between thalamo-cortical and cortico-thalamic signals. Whereas there has been significant interest in the role of the RE in organizing thalamo-cortical signaling, information on the activity of the RE in the awake animal is scant. Here we investigated the activity of neurons within the ‘motor’ compartment of the RE in the awake, unrestrained cat during simple locomotion on a flat surface and complex locomotion along a horizontal ladder that required visual control of stepping. The activity of 88% of neurons in this region was modulated during locomotion. Neurons with receptive fields on the shoulder were located dorsally in the nucleus and had regular discharges; during locomotion they had relatively low activity and modest magnitudes of stride-related modulation, and their group activity was distributed over the stride. In contrast, neurons with receptive fields on the wrist/paw were located more ventrally, often discharged sleep-type bursts during locomotion, were very active and profoundly modulated, and their group activity was concentrated in the swing and end of stance. 75% of RE neurons had different activity during the two locomotion tasks. We conclude that during locomotion the RE differentially gates thalamo-cortical signals transmitted during different phases of the stride, in relation to different parts of the limb, and the type of locomotion task. PMID:23136421

  8. 49 CFR 1242.22 - Shop buildings-locomotives (account XX-19-24).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Shop buildings-locomotives (account XX-19-24). 1242.22 Section 1242.22 Transportation Other Regulations Relating to Transportation (Continued) SURFACE... Structures § 1242.22 Shop buildings—locomotives (account XX-19-24). Separate common expenses according...

  9. 49 CFR 1242.22 - Shop buildings-locomotives (account XX-19-24).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Shop buildings-locomotives (account XX-19-24). 1242.22 Section 1242.22 Transportation Other Regulations Relating to Transportation (Continued) SURFACE... Structures § 1242.22 Shop buildings—locomotives (account XX-19-24). Separate common expenses according...

  10. No slip locomotion of hatchling sea turtles on granular media

    NASA Astrophysics Data System (ADS)

    Mazouchova, Nicole; Li, Chen; Gravish, Nick; Savu, Andrei; Goldman, Daniel

    2009-11-01

    Sea turtle locomotion occurs predominantly in aquatic environments. However after hatching from a nest on a beach, the juvenile turtles (hatchlings), must run across several hundred meters of granular media to reach the water. To discover how these organisms use aquatically adapted limbs for effective locomotion on sand, we use high speed infrared video to record hatchling Loggerhead sea turtles (Caretta caretta) kinematics in a field site on Jekyll Island, GA, USA. A portable fluidized bed trackway allows variation of the properties of the granular bed including volume fraction and angle up to the angle of repose. Despite being adapted for life in water, on all treatments the turtles use strategies similar to terrestrial organisms when moving on sand. Speeds up to 3 BL/sec are generated not by paddling in sand, but by limb movement that minimizes slip of the flippers, thus maintaining force below the yield stress of the medium. We predict turtle speed using a model which incorporates the yield stress of the granular medium as a function of surface angle.

  11. The dynamic study of locomotives under saturated adhesion

    NASA Astrophysics Data System (ADS)

    Yuan, Yao; Hong-jun, Zhang; Ye-ming, Li; Shi-hui, Luo

    2011-08-01

    In order to study the dynamic behaviours of locomotives under saturated adhesion, the stability and characteristics of stick-slip vibration are analysed using the concepts of mean and dynamic slip rates. The longitudinal vibration phenomenon of the wheelset when stick-slip occurs is put forward and its formation mechanism is made clear innovatively. The stick-slip vibration is a dynamic process between the stick and the slip states. The decreasing of mean and dynamic slip rates is conducive to its stability, which depends on the W/R adhesion damping. The torsion vibration of the driving system and the longitudinal vibration of the wheelset are coupled through the longitudinal tangential force when the wheelset alternates between the stick and the slip states. The longitudinal oscillation frequencies of the wheelset are integral multiples of the natural frequency of torsion vibration of the driving system. A train dynamic model integrated with an electromechanical and a control system is established to simulate the stick-slip vibration phenomenon under saturated adhesion to verify the theoretical analysis. The results show that increases of the longitudinal axle guidance stiffness and the motor suspension stiffness are beneficial to the stick-slip vibration stability and the locomotive's traction ability. The optimised matching of the longitudinal axle guidance stiffness and the motor suspension stiffness are helpful to avoid longitudinal resonance when the stick-slip vibration occurs.

  12. Snowmobile driving and symptoms of the locomotive organs.

    PubMed

    Näyhä, S; Anttonen, H; Hassi, J

    1994-01-01

    The role of snowmobile driving as a factor in symptoms of the locomotive organs was examined in 1,793 reindeer herding men using a postal questionnaire. Thirty-eight % of the respondents reported troubles in the upper limbs and shoulders which according to their own judgement were caused by snowmobile driving, and 34% reported such symptoms in the knees and 42% in the back. Aching, pain or tenderness upon movement in at least one joint during the current year, inquired by independent questions, were reported by 46% of the men. The prevalence of joint symptoms felt in the elbow (reported by 15% of the subjects), wrist (13%), fingers (10%), shoulder (22%) and knees (20%) increased by a factor of 1.6-2.5 from those driving a snowmobile 1-20 days a year to those driving 150 days or more. The findings confirm earlier reports of increased occurrence of symptoms in the locomotive organs in snowmobile drivers and justify technical and other preventive measures.

  13. Human Locomotion under Reduced Gravity Conditions: Biomechanical and Neurophysiological Considerations

    PubMed Central

    Sylos-Labini, Francesca; Ivanenko, Yuri P.

    2014-01-01

    Reduced gravity offers unique opportunities to study motor behavior. This paper aims at providing a review on current issues of the known tools and techniques used for hypogravity simulation and their effects on human locomotion. Walking and running rely on the limb oscillatory mechanics, and one way to change its dynamic properties is to modify the level of gravity. Gravity has a strong effect on the optimal rate of limb oscillations, optimal walking speed, and muscle activity patterns, and gait transitions occur smoothly and at slower speeds at lower gravity levels. Altered center of mass movements and interplay between stance and swing leg dynamics may challenge new forms of locomotion in a heterogravity environment. Furthermore, observations in the lack of gravity effects help to reveal the intrinsic properties of locomotor pattern generators and make evident facilitation of nonvoluntary limb stepping. In view of that, space neurosciences research has participated in the development of new technologies that can be used as an effective tool for gait rehabilitation. PMID:25247179

  14. Controlling legs for locomotion-insights from robotics and neurobiology.

    PubMed

    Buschmann, Thomas; Ewald, Alexander; von Twickel, Arndt; Büschges, Ansgar

    2015-06-29

    Walking is the most common terrestrial form of locomotion in animals. Its great versatility and flexibility has led to many attempts at building walking machines with similar capabilities. The control of walking is an active research area both in neurobiology and robotics, with a large and growing body of work. This paper gives an overview of the current knowledge on the control of legged locomotion in animals and machines and attempts to give walking control researchers from biology and robotics an overview of the current knowledge in both fields. We try to summarize the knowledge on the neurobiological basis of walking control in animals, emphasizing common principles seen in different species. In a section on walking robots, we review common approaches to walking controller design with a slight emphasis on biped walking control. We show where parallels between robotic and neurobiological walking controllers exist and how robotics and biology may benefit from each other. Finally, we discuss where research in the two fields diverges and suggest ways to bridge these gaps.

  15. Locomotion in stroke subjects: interactions between unaffected and affected sides.

    PubMed

    Kloter, Evelyne; Wirz, Markus; Dietz, Volker

    2011-03-01

    The aim of this study was to evaluate the sensorimotor interactions between unaffected and affected sides of post-stroke subjects during locomotion. In healthy subjects, stimulation of the tibial nerve during the mid-stance phase is followed by electromyography responses not only in the ipsilateral tibialis anterior, but also in the proximal arm muscles of both sides, with larger amplitudes prior to swing over an obstacle compared with normal swing. In post-stroke subjects, the electromyography responses were stronger on both sides when the tibial nerve of the unaffected leg was stimulated compared with stimulation of the affected leg. This difference was more pronounced when stimuli were applied prior to swing over an obstacle than prior to normal swing. This indicates an impaired processing of afferent input from the affected leg resulting in attenuated and little task-modulated reflex responses in the arm muscles on both sides. In contrast, an afferent volley from the unaffected leg resulted in larger electromyography responses, even in the muscles of the affected arm. Arm muscle activations were stronger during swing over an obstacle than during normal swing, with no difference in electromyography amplitudes between the unaffected and affected sides. It is concluded that the deficits of the affected arm are compensated for by influences from the unaffected side. These observations indicate strong mutual influences between unaffected and affected sides during locomotion of post-stroke subjects, which might be used to optimize rehabilitation approaches.

  16. Chronic jet lag impairs startle-induced locomotion in Drosophila.

    PubMed

    Vaccaro, Alexandra; Birman, Serge; Klarsfeld, André

    2016-12-01

    Endogenous circadian clocks with ~24-h periodicity are found in most organisms from cyanobacteria to humans. Daylight synchronizes these clocks to solar time. In humans, shift-work and jet lag perturb clock synchronization, and such perturbations, when repeated or chronic, are strongly suspected to be detrimental to healthspan. Here we investigated locomotor aging and longevity in Drosophila melanogaster with genetically or environmentally disrupted clocks. We compared two mutations in period (per, a gene essential for circadian rhythmicity in Drosophila), after introducing them in a common reference genetic background: the arrhythmic per(01), and per(T) which displays robust short 16-h rhythms. Compared to the wild type, both per mutants showed reduced longevity and decreased startle-induced locomotion in aging flies, while spontaneous locomotor activity was not impaired. The per(01) phenotypes were generally less severe than those of per(T), suggesting that chronic jet lag is more detrimental to aging than arrhythmicity in Drosophila. Interestingly, the adjustment of environmental light-dark cycles to the endogenous rhythms of the per(T) mutant fully suppressed the acceleration in the age-related decline of startle-induced locomotion, while it accelerated this decline in wild-type flies. Overall, our results show that chronic jet lag accelerates a specific form of locomotor aging in Drosophila, and that this effect can be alleviated by environmental changes that ameliorate circadian rhythm synchronization.

  17. The effect of reins on kinetic variables of locomotion.

    PubMed

    Biau, S; Couve, O; Lemaire, S; Barrey, E

    2002-09-01

    The equestrian literature and reports of experienced riders indicated that attitude of a horse's head and neck is related to the equine locomotion characteristics. The purpose of this study was to quantify the effects of 3 types of reins on locomotion at walk and trot. Eight saddle horses were tested in an automatic walker without reins, with rubber bands, Chambons and Back lift, using the same procedure. The rubber bands closed the head-neck angle, whereas the Chambons and the Back lift opened it. The gait characteristics were measured with the Equimetrix gait analysis system. Two accelerometric devices were fixed on the sternum and sacrum to measure the kinetic characteristics of the fore- and hindlimbs at walk and trot. Analysis of variance was used to test the effects of reins on the fore- and hindlimbs. All 3 types of reins significantly (P<0.05) modified walk and trot, with increased forelimb propulsion at the trot (P<0.05). Chambons increased the dorsoventral activity of the hindlimbs at the trot and hindlimb propulsion at the walk (P<0.05). Back lift increased forelimb dorsoventral activity both at the trot and walk (P<0.05). It was concluded that the Chambons increased the activity of the hindlimbs while Back lift increased that of the forelimbs. The use of reins modified the head placement and the fore- and hindlimbs activity. The specific effect of each type of rein can be used for training, rehabilitation or management of locomotor's injury.

  18. Stability may not compromise Maneuverability in Aquatic Periodic Locomotion

    NASA Astrophysics Data System (ADS)

    Kanso, Eva; Jing, Fangxu

    2014-11-01

    Most aquatic vertebrates swim by lateral flapping of their bodies and caudal fins. While much effort has been devoted to understanding the flapping kinematics and its influence on the swimming efficiency, little is known about the stability (or lack of) of periodic swimming. It is believed that stability limits maneuverability and body designs/flapping motions that are adapted for stable swimming are not suitable for high maneuverability and vice versa. Here, we consider an idealized model of a planar elliptic body undergoing prescribed periodic heaving and pitching in a perfect fluid. We show that periodic locomotion depends on several parameters including the aspect ratio of the body and the amplitude and phase of the prescribed flapping. We then study the stability of periodic locomotion using Floquet theory. We find that interesting trends of switching between stable and unstable motions emerge and evolve as we continuously vary the parameter values. This suggests that, when it comes to live organisms, maneuverability and stability need not be thought of as disjoint properties, rather the organism may manipulate its motion in favor of one or the other depending on the task at hand. This work is partially supported by the National Science Foundation through the CAREER Award CMMI 06-44925 and the Grant CCF 08-11480.

  19. Data-driven stochastic modelling of zebrafish locomotion.

    PubMed

    Zienkiewicz, Adam; Barton, David A W; Porfiri, Maurizio; di Bernardo, Mario

    2015-11-01

    In this work, we develop a data-driven modelling framework to reproduce the locomotion of fish in a confined environment. Specifically, we highlight the primary characteristics of the motion of individual zebrafish (Danio rerio), and study how these can be suitably encapsulated within a mathematical framework utilising a limited number of calibrated model parameters. Using data captured from individual zebrafish via automated visual tracking, we develop a model using stochastic differential equations and describe fish as a self propelled particle moving in a plane. Based on recent experimental evidence of the importance of speed regulation in social behaviour, we extend stochastic models of fish locomotion by introducing experimentally-derived processes describing dynamic speed regulation. Salient metrics are defined which are then used to calibrate key parameters of coupled stochastic differential equations, describing both speed and angular speed of swimming fish. The effects of external constraints are also included, based on experimentally observed responses. Understanding the spontaneous dynamics of zebrafish using a bottom-up, purely data-driven approach is expected to yield a modelling framework for quantitative investigation of individual behaviour in the presence of various external constraints or biological assays.

  20. Asymmetric Walkway: A Novel Behavioral Assay for Studying Asymmetric Locomotion

    PubMed Central

    Tuntevski, Kiril; Ellison, Ryan; Yakovenko, Sergiy

    2016-01-01

    Behavioral assays are commonly used for the assessment of sensorimotor impairment in the central nervous system (CNS). The most sophisticated methods for quantifying locomotor deficits in rodents is to measure minute disturbances of unconstrained gait overground (e.g., manual BBB score or automated CatWalk). However, cortical inputs are not required for the generation of basic locomotion produced by the spinal central pattern generator (CPG). Thus, unconstrained walking tasks test locomotor deficits due to motor cortical impairment only indirectly. In this study, we propose a novel, precise foot-placement locomotor task that evaluates cortical inputs to the spinal CPG. An instrumented peg-way was used to impose symmetrical and asymmetrical locomotor tasks mimicking lateralized movement deficits. We demonstrate that shifts from equidistant inter-stride lengths of 20% produce changes in the forelimb stance phase characteristics during locomotion with preferred stride length. Furthermore, we propose that the asymmetric walkway allows for measurements of behavioral outcomes produced by cortical control signals. These measures are relevant for the assessment of impairment after cortical damage. PMID:26863182