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Sample records for locomotive operation

  1. 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...

  2. 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...

  3. 49 CFR 236.505 - Proper operative relation between parts along roadway and parts on locomotive.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... roadway and parts on locomotive. 236.505 Section 236.505 Transportation Other Regulations Relating to... SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.505 Proper operative relation between parts along roadway and parts on locomotive....

  4. 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... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Rules and Instructions; Locomotives § 236.566 Locomotive of each train operating...

  5. 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

    ... coupling operations, and retarders shall be performed in accordance with the requirements of 40 CFR part... 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...

  6. 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

    ... coupling operations, and retarders shall be performed in accordance with the requirements of 40 CFR part... 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...

  7. 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

    ... coupling operations, and retarders shall be performed in accordance with the requirements of 40 CFR part... 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...

  8. 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

    ... coupling operations, and retarders shall be performed in accordance with the requirements of 40 CFR part... 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...

  9. 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

    ... coupling operations, and retarders shall be performed in accordance with the requirements of 40 CFR part... 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...

  10. 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...

  11. 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...

  12. 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...; yard and terminal clerical; locomotive fuel; electric power purchased/produced for motive...

  13. 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...

  14. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Operation standards (stationary locomotives at 30 meters). 210.31 Section 210.31 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION...

  15. 40 CFR 201.11 - Standard for locomotive operation under stationary conditions.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 26 2013-07-01 2013-07-01 false Standard for locomotive operation under stationary conditions. 201.11 Section 201.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS NOISE EMISSION STANDARDS FOR TRANSPORTATION...

  16. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Operation standards (moving locomotives and rail cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Operation standards (stationary locomotives at 30 meters). 210.31 Section 210.31 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION...

  18. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Operation standards (moving locomotives and rail cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION...

  19. 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) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION...

  20. 49 CFR 210.31 - Operation standards (stationary locomotives at 30 meters).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Operation standards (stationary locomotives at 30 meters). 210.31 Section 210.31 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION...

  1. 49 CFR 210.29 - Operation standards (moving locomotives and rail cars).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Operation standards (moving locomotives and rail cars). 210.29 Section 210.29 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION...

  2. 40 CFR 201.11 - Standard for locomotive operation under stationary conditions.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 25 2011-07-01 2011-07-01 false Standard for locomotive operation under stationary conditions. 201.11 Section 201.11 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) NOISE ABATEMENT PROGRAMS NOISE EMISSION STANDARDS FOR TRANSPORTATION...

  3. 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) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION...

  4. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... segment equipped with a PTC system shall be controlled by a locomotive equipped with an onboard PTC... shall include in its PTCIP specific goals for progressive implementation of onboard systems and... operative PTC onboard equipment. The PTCIP shall include a brief but sufficient explanation of how...

  5. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... segment equipped with a PTC system shall be controlled by a locomotive equipped with an onboard PTC... shall include in its PTCIP specific goals for progressive implementation of onboard systems and... operative PTC onboard equipment. The PTCIP shall include a brief but sufficient explanation of how...

  6. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... segment equipped with a PTC system shall be controlled by a locomotive equipped with an onboard PTC... shall include in its PTCIP specific goals for progressive implementation of onboard systems and... operative PTC onboard equipment. The PTCIP shall include a brief but sufficient explanation of how...

  7. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... segment equipped with a PTC system shall be controlled by a locomotive equipped with an onboard PTC... shall include in its PTCIP specific goals for progressive implementation of onboard systems and... operative PTC onboard equipment. The PTCIP shall include a brief but sufficient explanation of how...

  8. 49 CFR 236.1006 - Equipping locomotives operating in PTC territory.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... segment equipped with a PTC system shall be controlled by a locomotive equipped with an onboard PTC... shall include in its PTCIP specific goals for progressive implementation of onboard systems and... operative PTC onboard equipment. The PTCIP shall include a brief but sufficient explanation of how...

  9. 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... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and... train stop, train control or cab signal territory; equipped. The locomotive from which brakes...

  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... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and... train stop, train control or cab signal territory; equipped. The locomotive from which brakes...

  11. 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... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and... train stop, train control or cab signal territory; equipped. The locomotive from which brakes...

  12. 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... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and... train stop, train control or cab signal territory; equipped. The locomotive from which brakes...

  13. 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 signals, retarders, and humps; and servicing locomotives (accounts XX-52-64, XX-52-65, XX-52-66, XX-52-59, XX-52-67, XX-52-68 and...

  14. 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.

  15. 49 CFR 236.927 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... following elements must be addressed: (1) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or...

  16. 49 CFR 236.1047 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or enter data to, the system, such as consist data, and...

  17. 49 CFR 236.1047 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or enter data to, the system, such as consist data, and...

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

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... following elements must be addressed: (1) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or...

  19. 49 CFR 236.927 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... following elements must be addressed: (1) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or...

  20. 49 CFR 236.1047 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or enter data to, the system, such as consist data, and...

  1. 49 CFR 236.1047 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or enter data to, the system, such as consist data, and...

  2. 49 CFR 236.927 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... following elements must be addressed: (1) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or...

  3. 49 CFR 236.927 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... following elements must be addressed: (1) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or...

  4. 49 CFR 236.1047 - Training specific to locomotive engineers and other operating personnel.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Familiarization with train control equipment onboard the locomotive and the functioning of that equipment as part of the system and in relation to other onboard systems under that person's control; (2) Any actions required of the onboard personnel to enable, or enter data to, the system, such as consist data, and...

  5. 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.

  6. 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... Recordkeeping Requirements § 230.21 Steam locomotive number change. When a steam locomotive number is changed, the steam locomotive owner and/or operator must reflect the change in the upper right-hand corner...

  7. 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

  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, 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...

  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, 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...

  10. 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...

  11. 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...

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... steam locomotive boiler, the steam locomotive owner and/or operator shall file with the FRA Regional... the boiler. Whenever welded or riveted repairs are performed on stayed portions of a steam...

  17. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... steam locomotive boiler, the steam locomotive owner and/or operator shall file with the FRA Regional... the boiler. Whenever welded or riveted repairs are performed on stayed portions of a steam...

  18. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... steam locomotive boiler, the steam locomotive owner and/or operator shall file with the FRA Regional... the boiler. Whenever welded or riveted repairs are performed on stayed portions of a steam...

  19. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... steam locomotive boiler, the steam locomotive owner and/or operator shall file with the FRA Regional... the boiler. Whenever welded or riveted repairs are performed on stayed portions of a steam...

  20. 49 CFR 230.20 - Alteration and repair report for steam locomotive boilers.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... boilers. (a) Alterations. When an alteration is made to a steam locomotive boiler, the steam locomotive... steam locomotive boiler, the steam locomotive owner and/or operator shall file with the FRA Regional... the boiler. Whenever welded or riveted repairs are performed on stayed portions of a steam...

  1. 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

  2. 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…

  3. 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...

  4. 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...

  5. 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...

  6. 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...

  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, 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...

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. Forcing contact inhibition of locomotion

    PubMed Central

    Roycroft, Alice; Mayor, Roberto

    2015-01-01

    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. PMID:25981318

  1. 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.

  2. Legless locomotion in lattices

    NASA Astrophysics Data System (ADS)

    Schiebel, Perrin; Dai, Jin; Gong, Chaohui; Serrano, Miguel M.; Mendelson, Joseph R., III; Choset, Howie; Goldman, Daniel I.

    2015-03-01

    By propagating waves from head to tail, limbless organisms like snakes can traverse terrain composed of rocks, foliage, soil and sand. Previous research elucidated how rigid obstacles influence snake locomotion by studying a model terrain-symmetric lattices of pegs placed in hard ground. We want to understand how different substrate-body interaction modes affect performance in desert-adapted snakes during transit of substrates composed of both rigid obstacles and granular media (GM). We tested Chionactis occipitalis, the Mojave shovel-nosed snake, in two laboratory treatments: lattices of 0 . 64 cm diameter obstacles arrayed on both a hard, slick substrate and in a GM of ~ 0 . 3 mm diameter glass particles. For all lattice spacings, d, speed through the hard ground lattices was less than that in GM lattices. However, maximal undulation efficiencies ηu (number of body lengths advanced per undulation cycle) in both treatments were comparable when d was intermediate. For other d, ηu was lower than this maximum in hard ground lattices, while on GM, ηu was insensitive to d. To systematically explore such locomotion, we tested a physical robot model of the snake; performance depended sensitively on base substrate, d and body wave parameters.

  3. 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

  4. Locomotion control of hybrid cockroach robots.

    PubMed

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

    2015-04-01

    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%.

  5. Locomotion control of hybrid cockroach robots.

    PubMed

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

    2015-04-01

    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

  6. Azimut: a multimodal locomotion robotic platform

    NASA Astrophysics Data System (ADS)

    Michaud, Francois; Letourneau, Dominic; Arsenault, Martin; Bergeron, Yann; Cadrin, Richard; Gagnon, Frederic; Legault, Marc-Antoine; Millette, Mathieu; Pare, Jean-Francois; Tremblay, Marie-Christine; Lepage, Pierre; Morin, Yan; Caron, Serge

    2003-09-01

    Other than from its sensing and processing capabilities, a mobile robotic platform can be limited in its use by its ability to move in the environment. A wheeled robot works well on flat surfaces. Tracks are useful over rough terrains, while legs allow a robot to move over obstacles. In this paper we present a new concept of mobile robot with the objective of combining different locomotion mechanisms on the same platform to increase its locomotion capabilities. After presenting a review of multi-modal robotic platforms, we describe the design of our robot called AZIMUT. AZIMUT combines wheels, legs and tracks to move in three-dimensional environments. The robot is symmetrical and is made of four independent leg-track-wheel articulations. It can move with its articulations up, down or straight, or move sideways without changing the robot's orientation. The robot could be used in surveillance and rescue missions, exploration or operation in hazardous environments.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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

  13. [Evolution of tetrapod locomotion].

    PubMed

    Gambarian, P P

    2002-01-01

    Fish-like ancestors of tetrapods did not need strong limb musculature because they inhabited waters and were practically imponderable. In the primitive tetrapods, principal function of the limbs was initially restricted to passive anchoring in the course of animal movements on the substrate by means of lateral bending of the body (undulation). However, progressive development of carrying function of tetrapod limbs lead to clearing the body off the substrate which reduced friction costs and made the tetrapods less dependent on the substrate properties. Along with this, the limbs became more important as the active locomotory organs. But at the beginning, this diminished locomotory speed as the momentum caused by undulation could no longer provide additional forward sliding. Locomotory function of the tetrapod limb could be carried out due to both retraction and pronation at the shoulder joint. Relatively short humerus of the primitive tetrapods made it indifferent which of these two particular actions lead to elongation of the steps. In most of the recent tetrapods with sprawling limbs (Urodela, Lacertilia Sphenodontia, Crocodilia), step elongation was carried out mainly by retraction at the shoulder joint. Contrary to this, in Tachyglossidae (Mammalia: Monotremata) retraction is absent while pronation at the shoulder joint becomes the most important component of step elongation. This made it possible to recognize two principal types, pronatory and retractory, of locomotion on the basis of the main movement in the phase of support. A mathematical model describing changes in step length during the phase of support in both of these types is elaborated. It takes into account relative sizes of stylopodium and zeugopodium, the angles of pronation and retraction at the shoulder joint, the angle of adduction at the elbow joint, and the angle of body undulation arc. It is shown on the basis of this model, varying of which of the above parameters is advantageous and which is

  14. Legless locomotion in lattices

    NASA Astrophysics Data System (ADS)

    Schiebel, Perrin; Goldman, Daniel I.

    2014-11-01

    Little is known about interactions between an animal body and complex terrestrial terrain like sand and boulders during legless, undulatory travel (e.g. snake locomotion). We study the locomotor performance of Mojave shovel-nosed snakes (Chionactisoccipitalis , ~ 35 cm long) using a simplified model of heterogeneous terrain: symmetric lattices of obstacles. To quantify performance we measure mean forward speed and slip angle, βs, defined as the angle between the instantaneous velocity and tangent vectors at each point on the body. We find that below a critical peg density the presence of granular media results in high speed (~ 60 cm/s), low average slip (βs ~6°) snake performance as compared to movement in the same peg densities on hard ground (~ 25 cm/s and βs ~15°). Above this peg density, performance on granular and hard substrates converges. Speed on granular media decreases with increasing peg density to that of the speed on hard ground, while speed on hard ground remains constant. Conversely, βs on hard ground trends toward that on granular media as obstacle density increases.

  15. The mechanics of slithering locomotion

    PubMed Central

    Hu, David L.; Nirody, Jasmine; Scott, Terri; Shelley, Michael J.

    2009-01-01

    In this experimental and theoretical study, we investigate the slithering of snakes on flat surfaces. Previous studies of slithering have rested on the assumption that snakes slither by pushing laterally against rocks and branches. In this study, we develop a theoretical model for slithering locomotion by observing snake motion kinematics and experimentally measuring the friction coefficients of snakeskin. Our predictions of body speed show good agreement with observations, demonstrating that snake propulsion on flat ground, and possibly in general, relies critically on the frictional anisotropy of their scales. We have also highlighted the importance of weight distribution in lateral undulation, previously difficult to visualize and hence assumed uniform. The ability to redistribute weight, clearly of importance when appendages are airborne in limbed locomotion, has a much broader generality, as shown by its role in improving limbless locomotion. PMID:19506255

  16. 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.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Investigation of the impact of locomotive creep control on wear under changing contact conditions

    NASA Astrophysics Data System (ADS)

    Tian, Ye; Liu, Sheng; Daniel, William(Bill) J. T.; Meehan, Paul A.

    2015-05-01

    This paper presents the locomotive traction controller performance with respect to the track wear under different operation conditions. In particular, an investigation into the dynamic response of a locomotive under changing wheel-rail friction conditions is performed with an aim to determine the effect of controller setting on track wear. Simulation using a full-scale longitudinal-vertical locomotive dynamic model shows that the appropriately designed creep threshold, controller, settings can effectively maintain a high tractive effort while avoiding excessive rail damage due to wear, especially during acceleration under low speed.

  4. Undulatory Locomotion of Magnetic Multilink Nanoswimmers.

    PubMed

    Jang, Bumjin; Gutman, Emiliya; Stucki, Nicolai; Seitz, Benedikt F; Wendel-García, Pedro D; Newton, Taylor; Pokki, Juho; Ergeneman, Olgaç; Pané, Salvador; Or, Yizhar; Nelson, Bradley J

    2015-07-01

    Micro- and nanorobots operating in low Reynolds number fluid environments require specialized swimming strategies for efficient locomotion. Prior research has focused on designs mimicking the rotary corkscrew motion of bacterial flagella or the planar beating motion of eukaryotic flagella. These biologically inspired designs are typically of uniform construction along their flagellar axis. This work demonstrates for the first time planar undulations of composite multilink nanowire-based chains (diameter 200 nm) induced by a planar-oscillating magnetic field. Those chains comprise an elastic eukaryote-like polypyrrole tail and rigid magnetic nickel links connected by flexible polymer bilayer hinges. The multilink design exhibits a high swimming efficiency. Furthermore, the manufacturing process enables tuning the geometrical and material properties to specific applications.

  5. 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... Locomotive Crashworthiness Design Requirements § 229.209 Alternative locomotive crashworthiness designs. (a... locomotive crashworthiness designs which are not consistent with any FRA-approved locomotive...

  6. 40 CFR 92.214 - Production locomotives and engines.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... locomotives or locomotive engines shall be representative of the engines, emission control systems, and fuel... 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 §...

  7. 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.

  8. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... locomotives, including cab cars and MU locomotives. (a)(1) The skin covering the forward-facing end of each... “skin” does not include forward-facing windows and doors. (b) The forward end structure of a cab car...

  9. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Forward end structure of locomotives, including... SAFETY STANDARDS Specific Requirements for Tier I Passenger Equipment § 238.209 Forward end structure of... locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate...

  10. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Forward end structure of locomotives, including... SAFETY STANDARDS Specific Requirements for Tier I Passenger Equipment § 238.209 Forward end structure of... locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate...

  11. 49 CFR 238.209 - Forward end structure of locomotives, including cab cars and MU locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Forward end structure of locomotives, including... SAFETY STANDARDS Specific Requirements for Tier I Passenger Equipment § 238.209 Forward end structure of... locomotive, including a cab car and an MU locomotive, shall be: (i) Equivalent to a 1/2-inch steel plate...

  12. 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.

  13. 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.

  14. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... applicable sections of the Safety Glazing Standards (49 CFR part 223), Locomotive Safety Standards (49 CFR part 229), Safety Appliance Standards (49 CFR part 231) and Power Brake Standards (49 CFR part 232), to... four years of experience in locomotive construction or maintenance. A bachelor's degree in...

  15. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... applicable sections of the Safety Glazing Standards (49 CFR part 223), Locomotive Safety Standards (49 CFR part 229), Safety Appliance Standards (49 CFR part 231) and Power Brake Standards (49 CFR part 232), to... four years of experience in locomotive construction or maintenance. A bachelor's degree in...

  16. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... applicable sections of the Safety Glazing Standards (49 CFR part 223), Locomotive Safety Standards (49 CFR part 229), Safety Appliance Standards (49 CFR part 231) and Power Brake Standards (49 CFR part 232), to... four years of experience in locomotive construction or maintenance. A bachelor's degree in...

  17. 77 FR 21311 - Locomotive Safety Standards

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-09

    .... Alerters are currently required on passenger locomotives pursuant to Sec. 238.237 (67 FR 19991), and are..., 2007 (72 FR 59216). FRA continued to utilize the RSAC process to address additional locomotive safety... text for these issues with minor clarifying modifications on January 12, 2011. See 76 FR 2199. The...

  18. 49 CFR 236.770 - Locomotive.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Definitions § 236.770 Locomotive. A self... 49 Transportation 4 2010-10-01 2010-10-01 false Locomotive. 236.770 Section 236.770 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT...

  19. 76 FR 8699 - Locomotive Safety Standards; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... NPRM related to locomotive safety standards. See 76 FR 2200. The NPRM established a public docket to... the proposed rule published January 12, 2011, at 76 FR 2200, remains March 14, 2011. FOR FURTHER... Federal Railroad Administration 49 CFR Parts 229 and 238 RIN 2130-AC16 Locomotive Safety...

  20. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before.... The locomotive shall be positioned on straight, level track. (6) Measurements shall be taken only when... between 20 percent and 95 percent inclusively; wind velocity is not more than 12 miles per hour and...

  1. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before.... The locomotive shall be positioned on straight, level track. (6) Measurements shall be taken only when... between 20 percent and 95 percent inclusively; wind velocity is not more than 12 miles per hour and...

  2. 49 CFR 212.215 - Locomotive inspector.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... applicable sections of the Safety Glazing Standards (49 CFR part 223), Locomotive Safety Standards (49 CFR part 229), Safety Appliance Standards (49 CFR part 231) and Power Brake Standards (49 CFR part 232), to... four years of experience in locomotive construction or maintenance. A bachelor's degree in...

  3. 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.

  4. Simulation of a Hybrid Locomotion Robot Vehicle

    NASA Astrophysics Data System (ADS)

    Aarnio, P.

    2002-10-01

    This study describes a simulation process of a mobile robot. The focus is in kinematic and dynamic behavior simulations of hybrid locomotion robot vehicles. This research is motivated by the development needs of the WorkPartner field service robot. The whole robot system consists of a mobile platform and a two-hand manipulator. The robot platform, called Hybtor, is a hybrid locomotion robot capable of walking and driving by wheels as well as combining these two locomotion modes. This study describes first the general problems and their solutions in the dynamic simulation of mobile robots. A kinematic and dynamic virtual model of the Hybtor robot was built and simulations were carried out using one commercial simulation tool. Walking, wheel driven and rolking mode locomotion, which is a special hybrid locomotion style, has been simulated and analyzed. Position and force control issues during obstacle overrun and climbing were also studied.

  5. A hybrid active/passive exhaust noise control system for locomotives

    NASA Astrophysics Data System (ADS)

    Remington, Paul J.; Knight, J. Scott; Hanna, Doug; Rowley, Craig

    2005-01-01

    A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2-12-in. speakers per enclosure as actuators, eight roof-mounted electret microphones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal. .

  6. A hybrid active/passive exhaust noise control system for locomotives.

    PubMed

    Remington, Paul J; Knight, J Scott; Hanna, Doug; Rowley, Craig

    2005-01-01

    A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2-12-in. speakers per enclosure as actuators, eight roof-mounted electret microphones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal.

  7. A hybrid active/passive exhaust noise control system for locomotives.

    PubMed

    Remington, Paul J; Knight, J Scott; Hanna, Doug; Rowley, Craig

    2005-01-01

    A prototype hybrid system consisting of active and passive components for controlling far-field locomotive exhaust noise has been designed, assembled, and tested on a locomotive. The system consisted of a resistive passive silencer for controlling high-frequency broadband noise and a feedforward multiple-input, multiple-output active control system for suppressing low-frequency tonal noise. The active system used ten roof-mounted bandpass speaker enclosures with 2-12-in. speakers per enclosure as actuators, eight roof-mounted electret microphones as residual sensors, and an optical tachometer that sensed locomotive engine speed as a reference sensor. The system was installed on a passenger locomotive and tested in an operating rail yard. Details of the system are described and the near-field and far-field noise reductions are compared against the design goal. PMID:15704399

  8. Optimizing Locomotion Controllers Using Biologically-Based Actuators and Objectives

    PubMed Central

    Wang, Jack M.; Hamner, Samuel R.; Delp, Scott L.; Koltun, Vladlen

    2015-01-01

    We present a technique for automatically synthesizing walking and running controllers for physically-simulated 3D humanoid characters. The sagittal hip, knee, and ankle degrees-of-freedom are actuated using a set of eight Hill-type musculotendon models in each leg, with biologically-motivated control laws. The parameters of these control laws are set by an optimization procedure that satisfies a number of locomotion task terms while minimizing a biological model of metabolic energy expenditure. We show that the use of biologically-based actuators and objectives measurably increases the realism of gaits generated by locomotion controllers that operate without the use of motion capture data, and that metabolic energy expenditure provides a simple and unifying measurement of effort that can be used for both walking and running control optimization. PMID:26251560

  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 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...

  11. 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...

  12. 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...

  13. 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...

  14. 49 CFR 230.106 - Steam locomotive frame.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 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...

  15. 40 CFR 1033.652 - Special provisions for exported locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Special Compliance Provisions § 1033.652 Special provisions for exported locomotives. (a) Uncertified locomotives. Locomotives covered by an export exemption under 40 CFR 1068.230 may be introduced into U.S. commerce prior to being exported, but may not...

  16. 40 CFR 1033.652 - Special provisions for exported locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Special Compliance Provisions § 1033.652 Special provisions for exported locomotives. (a) Uncertified locomotives. Locomotives covered by an export exemption under 40 CFR 1068.230 may be introduced into U.S. commerce prior to being exported, but may not...

  17. 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...

  18. 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...

  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 230.21 - 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...

  1. 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...

  2. 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...

  3. 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...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. Motoneuronal and muscle synergies involved in cat hindlimb control during fictive and real locomotion: a comparison study.

    PubMed

    Markin, Sergey N; Lemay, Michel A; Prilutsky, Boris I; Rybak, Ilya A

    2012-04-01

    We compared the activity profiles and synergies of spinal motoneurons recorded during fictive locomotion evoked in immobilized decerebrate cat preparations by midbrain stimulation to the activity profiles and synergies of the corresponding hindlimb muscles obtained during forward level walking in cats. The fictive locomotion data were collected in the Spinal Cord Research Centre, University of Manitoba, and provided by Dr. David McCrea; the real locomotion data were obtained in the laboratories of M. A. Lemay and B. I. Prilutsky. Scatterplot representation and minimum spanning tree clustering algorithm were used to identify the possible motoneuronal and muscle synergies operating during both fictive and real locomotion. We found a close similarity between the activity profiles and synergies of motoneurons innervating one-joint muscles during fictive locomotion and the profiles and synergies of the corresponding muscles during real locomotion. However, the activity patterns of proximal nerves controlling two-joint muscles, such as posterior biceps and semitendinosus (PBSt) and rectus femoris (RF), were not uniform in fictive locomotion preparations and differed from the activity profiles of the corresponding two-joint muscles recorded during forward level walking. Moreover, the activity profiles of these nerves and the corresponding muscles were unique and could not be included in the synergies identified in fictive and real locomotion. We suggest that afferent feedback is involved in the regulation of locomotion via motoneuronal synergies controlled by the spinal central pattern generator (CPG) but may also directly affect the activity of motoneuronal pools serving two-joint muscles (e.g., PBSt and RF). These findings provide important insights into the organization of the spinal CPG in mammals, the motoneuronal and muscle synergies engaged during locomotion, and their afferent control.

  9. Vertebral function during tadpole locomotion.

    PubMed

    Azizi, Emanuel; Landberg, Tobias; Wassersug, Richard J

    2007-01-01

    Most anuran larvae show large lateral oscillations at both the tip of the tail and the snout while swimming in a straight line. Although the lateral deflections at the snout have long been considered an inefficient aspect of tadpole locomotion, a recent hydrodynamic model suggests that they may in fact help generate thrust. It is not clear though exactly where this bending takes place. The vertebral column is extremely short and seemingly inflexible in anurans, and any axial flexion that might occur there is hidden within the globose body of the tadpole. Here we test the hypothesis that lateral deflections of the snout correlate with bending of the vertebral column within the torso of tadpoles. To quantify vertebral curvature, three sonomicrometry crystals were surgically implanted along the dorsal midline in locations corresponding to the anterior, middle, and posterior region of the presacral vertebral column. Swimming trials were conducted in a flume where synchronized video recordings were collected in dorsal view. Our results confirm that cyclic lateral bending occurs along the vertebral column during swimming and indicate that vertebral curvature is temporally in phase with lateral oscillation of the snout. Lateral oscillation of the snout increased significantly with increasing vertebral curvature. Similarly, tail beat amplitude also increases significantly with increasing vertebral curvature. Our results suggest that cyclic lateral flexion of the vertebral column, activated by the axial muscle within the torso of tadpoles contributes to snout oscillations and the generation of thrust during undulatory swimming in anuran larvae.

  10. Locomotive wheel 3D reconstruction

    NASA Astrophysics Data System (ADS)

    Guan, Xin; Luo, Zhisheng; Gao, Xiaorong; Wu, Jianle

    2010-08-01

    In the article, a system, which is used to reconstruct locomotive wheels, is described, helping workers detect the condition of a wheel through a direct view. The system consists of a line laser, a 2D camera, and a computer. We use 2D camera to capture the line-laser light reflected by the object, a wheel, and then compute the final coordinates of the structured light. Finally, using Matlab programming language, we transform the coordinate of points to a smooth surface and illustrate the 3D view of the wheel. The article also proposes the system structure, processing steps and methods, and sets up an experimental platform to verify the design proposal. We verify the feasibility of the whole process, and analyze the results comparing to standard date. The test results show that this system can work well, and has a high accuracy on the reconstruction. And because there is still no such application working in railway industries, so that it has practical value in railway inspection system.

  11. Robot locomotion on weak ground

    NASA Astrophysics Data System (ADS)

    Qian, Feifei; Li, Chen; Umbanhowar, Paul; Goldman, Daniel

    2012-11-01

    Natural substrates like sand, soil, and leaf litter vary widely in penetration resistance. Little is known about how animals (and increasingly robots) respond to this variation. To address this deficit, we built an air fluidized bed trackway, in which we control penetration resistance of 1mm granular substrates down to zero by increasing the upward flow rate, Q , to the fluidization transition. Using a 2 . 5 kg bio-inspired hexapedal robot as our model locomotor, we systematically study how locomotion performance (average forward speed, v) varies with penetration resistance, limb kinematics, and foot morphology. Average robot speed decreases with increasing Q, and decreases faster for robots with higher leg frequency or narrower leg width. A previously developed model, which captured the robot's performance on granular media with Q = 0 , also captures the observed performance for weakened states with Q > 0 . A single dimensionless control parameter from the model, which combines gait and ground parameters, determines v for all penetration resistances. Our ground control technique and modeling approach provide a way to probe and understand the limits of locomotor performance on yielding substrates.

  12. 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.

  13. 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.

  14. 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.

  15. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were 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...

  16. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were 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...

  17. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Recall... manufacturer or remanufacturer, which may be used to report difficulty in obtaining recall repairs. (10)...

  18. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Recall... manufacturer or remanufacturer, which may be used to report difficulty in obtaining recall repairs. (10)...

  19. 40 CFR 92.707 - Notification to locomotive or locomotive engine owners.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... defined in 40 CFR part 92. These standards or family emission limits, as defined in 40 CFR part 92 were... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Recall... manufacturer or remanufacturer, which may be used to report difficulty in obtaining recall repairs. (10)...

  20. 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

  1. Circuits controlling vertebrate locomotion: moving in a new direction

    PubMed Central

    Goulding, Martyn

    2010-01-01

    Neurobiologists have long sought to understand how circuits in the nervous system are organized and generate the precise neural outputs that underlie particular behaviors. The motor circuits in the spinal cord that control locomotion and are commonly referred to as central pattern generator (CPG) networks, provide an experimentally tractable model system for investigating how moderately complex ensembles of neurons generate select motor behaviors. The advent of novel molecular genetic techniques coupled with recent advances in our knowledge of spinal cord development means that a comprehensive understanding of how the motor circuitry is organized and operates may now be within our grasp. PMID:19543221

  2. 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.

  3. 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.

  4. Passive appendages aid locomotion through symmetry breaking

    NASA Astrophysics Data System (ADS)

    Bagheri, Shervin; Lacis, Ugis; Mazzino, Andrea; Kellay, Hamid; Brosse, Nicolas; Lundell, Fredrik; Ingremeau, Francois

    2014-11-01

    Plants and animals use plumes, barbs, tails, feathers, hairs, fins, and other types of appendages to aid locomotion. Despite their enormous variation, passive appendages may contribute to locomotion by exploiting the same physical mechanism. We present a new mechanism that applies to body appendages surrounded by a separated flow, which often develops behind moving bodies larger than a few millimeters. We use theory, experiments, and numerical simulations to show that bodies with protrusions turn and drift by exploiting a symmetry-breaking instability similar to the instability of an inverted pendulum. Our model explains why the straight position of an appendage in flowing fluid is unstable and how it stabilizes either to the left or right of the incoming fluid flow direction. The discovery suggests a new mechanism of locomotion that may be relevant for certain organisms; for example, how plumed seeds may drift without wind and how motile animals may passively reorient themselves.

  5. Analysis of fuel cell hybrid locomotives

    NASA Astrophysics Data System (ADS)

    Miller, Arnold R.; Peters, John; Smith, Brian E.; Velev, Omourtag A.

    Led by Vehicle Projects LLC, an international industry-government consortium is developing a 109 t, 1.2 MW road-switcher locomotive for commercial and military railway applications. As part of the feasibility and conceptual-design analysis, a study has been made of the potential benefits of a hybrid power plant in which fuel cells comprise the prime mover and a battery or flywheel provides auxiliary power. The potential benefits of a hybrid power plant are: (i) enhancement of transient power and hence tractive effort; (ii) regenerative braking; (iii) reduction of capital cost. Generally, the tractive effort of a locomotive at low speed is limited by wheel adhesion and not by available power. Enhanced transient power is therefore unlikely to benefit a switcher locomotive, but could assist applications that require high acceleration, e.g. subway trains with all axles powered. In most cases, the value of regeneration in locomotives is minimal. For low-speed applications such as switchers, the available kinetic energy and the effectiveness of traction motors as generators are both minimal. For high-speed heavy applications such as freight, the ability of the auxiliary power device to absorb a significant portion of the available kinetic energy is low. Moreover, the hybrid power plant suffers a double efficiency penalty, namely, losses occur in both absorbing and then releasing energy from the auxiliary device, which result in a net storage efficiency of no more than 50% for present battery technology. Capital cost in some applications may be reduced. Based on an observed locomotive duty cycle, a cost model shows that a hybrid power plant for a switcher may indeed reduce capital cost. Offsetting this potential benefit are the increased complexity, weight and volume of the power plant, as well as 20-40% increased fuel consumption that results from lower efficiency. Based on this analysis, the consortium has decided to develop a pure fuel cell road-switcher locomotive

  6. Energy balance of human locomotion in water.

    PubMed

    Pendergast, D; Zamparo, P; di Prampero, P E; Capelli, C; Cerretelli, P; Termin, A; Craig, A; Bushnell, D; Paschke, D; Mollendorf, J

    2003-10-01

    In this paper a complete energy balance for water locomotion is attempted with the aim of comparing different modes of transport in the aquatic environment (swimming underwater with SCUBA diving equipment, swimming at the surface: leg kicking and front crawl, kayaking and rowing). On the basis of the values of metabolic power (E), of the power needed to overcome water resistance (Wd) and of propelling efficiency (etaP=Wd/Wtot, where Wtot is the total mechanical power) as reported in the literature for each of these forms of locomotion, the energy cost per unit distance (C=E/v, where v is the velocity), the drag (performance) efficiency (etad=Wd/E) and the overall efficiency (etao=Wtot/E=etad/etaP) were calculated. As previously found for human locomotion on land, for a given metabolic power (e.g. 0.5 kW=1.43 l.min(-1) VO2) the decrease in C (from 0.88 kJ.m(-1) in SCUBA diving to 0.22 kJ.m(-1) in rowing) is associated with an increase in the speed of locomotion (from 0.6 m.s(-1) in SCUBA diving to 2.4 m.s(-1) in rowing). At variance with locomotion on land, however, the decrease in C is associated with an increase, rather than a decrease, of the total mechanical work per unit distance (Wtot, kJ.m(-1)). This is made possible by the increase of the overall efficiency of locomotion (etao=Wtot/E=Wtot/C) from the slow speeds (and loads) of swimming to the high speeds (and loads) attainable with hulls and boats (from 0.10 in SCUBA diving to 0.29 in rowing).

  7. Energy balance of human locomotion in water.

    PubMed

    Pendergast, D; Zamparo, P; di Prampero, P E; Capelli, C; Cerretelli, P; Termin, A; Craig, A; Bushnell, D; Paschke, D; Mollendorf, J

    2003-10-01

    In this paper a complete energy balance for water locomotion is attempted with the aim of comparing different modes of transport in the aquatic environment (swimming underwater with SCUBA diving equipment, swimming at the surface: leg kicking and front crawl, kayaking and rowing). On the basis of the values of metabolic power (E), of the power needed to overcome water resistance (Wd) and of propelling efficiency (etaP=Wd/Wtot, where Wtot is the total mechanical power) as reported in the literature for each of these forms of locomotion, the energy cost per unit distance (C=E/v, where v is the velocity), the drag (performance) efficiency (etad=Wd/E) and the overall efficiency (etao=Wtot/E=etad/etaP) were calculated. As previously found for human locomotion on land, for a given metabolic power (e.g. 0.5 kW=1.43 l.min(-1) VO2) the decrease in C (from 0.88 kJ.m(-1) in SCUBA diving to 0.22 kJ.m(-1) in rowing) is associated with an increase in the speed of locomotion (from 0.6 m.s(-1) in SCUBA diving to 2.4 m.s(-1) in rowing). At variance with locomotion on land, however, the decrease in C is associated with an increase, rather than a decrease, of the total mechanical work per unit distance (Wtot, kJ.m(-1)). This is made possible by the increase of the overall efficiency of locomotion (etao=Wtot/E=Wtot/C) from the slow speeds (and loads) of swimming to the high speeds (and loads) attainable with hulls and boats (from 0.10 in SCUBA diving to 0.29 in rowing). PMID:12955519

  8. 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.

  9. 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

  10. 22. AERIAL VIEW LOOKING EAST SHOWING GRANT LOCOMOTIVE WORKS, UNION ...

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

    22. AERIAL VIEW LOOKING EAST SHOWING GRANT LOCOMOTIVE WORKS, UNION WORKS (ROSEN MILL), ROGERS LOCOMOTIVE AND MACHINE COMPANY AND IVANHOE MILL WHEELHOUSE UNDER RESTORATION. - Great Falls S. U. M. Historic District, Oliver Street, Paterson, Passaic County, NJ

  11. CSF-contacting neurons regulate locomotion by relaying mechanical stimuli to spinal circuits.

    PubMed

    Böhm, Urs Lucas; Prendergast, Andrew; Djenoune, Lydia; Nunes Figueiredo, Sophie; Gomez, Johanna; Stokes, Caleb; Kaiser, Sonya; Suster, Maximilliano; Kawakami, Koichi; Charpentier, Marine; Concordet, Jean-Paul; Rio, Jean-Paul; Del Bene, Filippo; Wyart, Claire

    2016-01-01

    Throughout vertebrates, cerebrospinal fluid-contacting neurons (CSF-cNs) are ciliated cells surrounding the central canal in the ventral spinal cord. Their contribution to modulate locomotion remains undetermined. Recently, we have shown CSF-cNs modulate locomotion by directly projecting onto the locomotor central pattern generators (CPGs), but the sensory modality these cells convey to spinal circuits and their relevance to innate locomotion remain elusive. Here, we demonstrate in vivo that CSF-cNs form an intraspinal mechanosensory organ that detects spinal bending. By performing calcium imaging in moving animals, we show that CSF-cNs respond to both passive and active bending of the spinal cord. In mutants for the channel Pkd2l1, CSF-cNs lose their response to bending and animals show a selective reduction of tail beat frequency, confirming the central role of this feedback loop for optimizing locomotion. Altogether, our study reveals that CSF-cNs constitute a mechanosensory organ operating during locomotion to modulate spinal CPGs. PMID:26946992

  12. CSF-contacting neurons regulate locomotion by relaying mechanical stimuli to spinal circuits

    PubMed Central

    Böhm, Urs Lucas; Prendergast, Andrew; Djenoune, Lydia; Nunes Figueiredo, Sophie; Gomez, Johanna; Stokes, Caleb; Kaiser, Sonya; Suster, Maximilliano; Kawakami, Koichi; Charpentier, Marine; Concordet, Jean-Paul; Rio, Jean-Paul; Del Bene, Filippo; Wyart, Claire

    2016-01-01

    Throughout vertebrates, cerebrospinal fluid-contacting neurons (CSF-cNs) are ciliated cells surrounding the central canal in the ventral spinal cord. Their contribution to modulate locomotion remains undetermined. Recently, we have shown CSF-cNs modulate locomotion by directly projecting onto the locomotor central pattern generators (CPGs), but the sensory modality these cells convey to spinal circuits and their relevance to innate locomotion remain elusive. Here, we demonstrate in vivo that CSF-cNs form an intraspinal mechanosensory organ that detects spinal bending. By performing calcium imaging in moving animals, we show that CSF-cNs respond to both passive and active bending of the spinal cord. In mutants for the channel Pkd2l1, CSF-cNs lose their response to bending and animals show a selective reduction of tail beat frequency, confirming the central role of this feedback loop for optimizing locomotion. Altogether, our study reveals that CSF-cNs constitute a mechanosensory organ operating during locomotion to modulate spinal CPGs. PMID:26946992

  13. 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.

  14. 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.

  15. 40 CFR 1033.335 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Manufacturer and... ensure that all emission related components are properly installed on the locomotive and are set to the...,000 miles prior to an audit. (d) A locomotive fails if any emission related components are found to...

  16. 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...

  17. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  18. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  19. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  20. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Road locomotives with corner stairways. 231.29... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must...

  1. 49 CFR 223.11 - Requirements for existing locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Requirements for existing locomotives. 223.11... be equipped with certified glazing in all locomotive cab windows after June 30, 1984. (d) Each... vandalism has a locomotive cab window that is broken or damaged so that the window fails to permit...

  2. 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... be equipped with certified glazing in all locomotive cab windows after June 30, 1984. (d) Each... vandalism has a locomotive cab window that is broken or damaged so that the window fails to permit...

  3. 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... body structure designed to meet or exceed the following minimum specifications: (1) The body...

  4. 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...

  5. 49 CFR 231.29 - Road locomotives with corner stairways.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD SAFETY APPLIANCE STANDARDS § 231.29 Road locomotives with corner stairways. After September 30, 1979, road locomotives with corner stairway openings must be... 49 Transportation 4 2010-10-01 2010-10-01 false Road locomotives with corner stairways....

  6. 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...

  7. 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...

  8. 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...

  9. 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...

  10. 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...

  11. 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...

  12. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before... Electrotechnical Commission (IEC) Standard 61672-1 (2002-05) for a Class 2 instrument. (2) An acoustic calibrator... with the acoustic calibrator immediately before and after compliance tests. Any change in the...

  13. 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

  14. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before... Electrotechnical Commission (IEC) Standard 61672-1 (2002-05) for a Class 2 instrument. (2) An acoustic calibrator... with the acoustic calibrator immediately before and after compliance tests. Any change in the...

  15. 49 CFR 229.129 - Locomotive horn.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... defectives equal to an AQL of 1% or less, as set forth in 7 CFR part 43. (2) Each locomotive built before... Electrotechnical Commission (IEC) Standard 61672-1 (2002-05) for a Class 2 instrument. (2) An acoustic calibrator... with the acoustic calibrator immediately before and after compliance tests. Any change in the...

  16. 77 FR 23159 - Locomotive Safety Standards; Correction

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-18

    ... rule related to locomotive safety standards. See 77 FR 21312. The final rule established a public... safety standards and comments on such petitions. That final rule mistakenly lists FR-2009- 0095... is FRA-2009-0094. The final rule issued on April 9, 2012, incorrectly identified docket number...

  17. 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.

  18. 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…

  19. Judgments of Path, Not Heading, Guide Locomotion

    ERIC Educational Resources Information Center

    Wilkie, Richard M.; Wann, John P.

    2006-01-01

    To steer a course through the world, people are almost entirely dependent on visual information, of which a key component is optic flow. In many models of locomotion, heading is described as the fundamental control variable; however, it has also been shown that fixating points along or near one's future path could be the basis of an efficient…

  20. 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. PMID:26047022

  1. 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.

  2. 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...

  3. 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...

  4. 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...

  5. 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...

  6. Intelligent mobility research for robotic locomotion in complex terrain

    NASA Astrophysics Data System (ADS)

    Trentini, Michael; Beckman, Blake; Digney, Bruce; Vincent, Isabelle; Ricard, Benoit

    2006-05-01

    The objective of the Autonomous Intelligent Systems Section of Defence R&D Canada - Suffield is best described by its mission statement, which is "to augment soldiers and combat systems by developing and demonstrating practical, cost effective, autonomous intelligent systems capable of completing military missions in complex operating environments." The mobility requirement for ground-based mobile systems operating in urban settings must increase significantly if robotic technology is to augment human efforts in these roles and environments. The intelligence required for autonomous systems to operate in complex environments demands advances in many fields of robotics. This has resulted in large bodies of research in areas of perception, world representation, and navigation, but the problem of locomotion in complex terrain has largely been ignored. In order to achieve its objective, the Autonomous Intelligent Systems Section is pursuing research that explores the use of intelligent mobility algorithms designed to improve robot mobility. Intelligent mobility uses sensing, control, and learning algorithms to extract measured variables from the world, control vehicle dynamics, and learn by experience. These algorithms seek to exploit available world representations of the environment and the inherent dexterity of the robot to allow the vehicle to interact with its surroundings and produce locomotion in complex terrain. The primary focus of the paper is to present the intelligent mobility research within the framework of the research methodology, plan and direction defined at Defence R&D Canada - Suffield. It discusses the progress and future direction of intelligent mobility research and presents the research tools, topics, and plans to address this critical research gap. This research will create effective intelligence to improve the mobility of ground-based mobile systems operating in urban settings to assist the Canadian Forces in their future urban operations.

  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. 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.

  9. Intermittent locomotion as an optimal control strategy

    PubMed Central

    Paoletti, P.; Mahadevan, L.

    2014-01-01

    Birds, fish and other animals routinely use unsteady effects to save energy by alternating between phases of active propulsion and passive coasting. Here, we construct a minimal model for such behaviour that can be couched as an optimal control problem via an analogy to travelling with a rechargeable battery. An analytical solution of the optimal control problem proves that intermittent locomotion has lower energy requirements relative to steady-state strategies. Additional realistic hypotheses, such as the assumption that metabolic cost at a given power should be minimal (the fixed gear hypothesis), a nonlinear dependence of the energy storage rate on propulsion and/or a preferred average speed, allow us to generalize the model and demonstrate the flexibility of intermittent locomotion with implications for biological and artificial systems. PMID:24711718

  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. Locomotion in complex fluids: Integral theorems

    NASA Astrophysics Data System (ADS)

    Lauga, Eric

    2014-08-01

    The biological fluids encountered by self-propelled cells display complex microstructures and rheology. We consider here the general problem of low-Reynolds number locomotion in a complex fluid. Building on classical work on the transport of particles in viscoelastic fluids, we demonstrate how to mathematically derive three integral theorems relating the arbitrary motion of an isolated organism to its swimming kinematics in a non-Newtonian fluid. These theorems correspond to three situations of interest, namely, (1) squirming motion in a linear viscoelastic fluid, (2) arbitrary surface deformation in a weakly non-Newtonian fluid, and (3) small-amplitude deformation in an arbitrarily non-Newtonian fluid. Our final results, valid for a wide-class of swimmer geometry, surface kinematics, and constitutive models, at most require mathematical knowledge of a series of Newtonian flow problems, and will be useful to quantity the locomotion of biological and synthetic swimmers in complex environments.

  12. 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.

  13. 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.

  14. 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. PMID:23155173

  15. Exotendons for assistance of human locomotion

    PubMed Central

    van den Bogert, Antonie J

    2003-01-01

    Background Powered robotic exoskeletons for assistance of human locomotion are currently under development for military and medical applications. The energy requirements for such devices are excessive, and this has become a major obstacle for practical applications. Legged locomotion in many animals, however, is very energy efficient. We propose that poly-articular elastic mechanisms are a major contributor to the economy of locomotion in such specialized animals. Consequently, it should be possible to design unpowered assistive devices that make effective use of similar mechanisms. Methods A passive assistive technology is presented, based on long elastic cords attached to an exoskeleton and guided by pulleys placed at the joints. A general optimization procedure is described for finding the best geometrical arrangement of such "exotendons" for assisting a specific movement. Optimality is defined either as minimal residual joint moment or as minimal residual joint power. Four specific exotendon systems with increasing complexity are considered. Representative human gait data were used to optimize each of these four systems to achieve maximal assistance for normal walking. Results The most complex exotendon system, with twelve pulleys per limb, was able to reduce the joint moments required for normal walking by 71% and joint power by 74%. A simpler system, with only three pulleys per limb, could reduce joint moments by 46% and joint power by 47%. Conclusion It is concluded that unpowered passive elastic devices can substantially reduce the muscle forces and the metabolic energy needed for walking, without requiring a change in movement. When optimally designed, such devices may allow independent locomotion in patients with large deficits in muscle function. PMID:14613503

  16. Chaotic exploration and learning of locomotion behaviors.

    PubMed

    Shim, Yoonsik; Husbands, Phil

    2012-08-01

    We present a general and fully dynamic neural system, which exploits intrinsic chaotic dynamics, for the real-time goal-directed exploration and learning of the possible locomotion patterns of an articulated robot of an arbitrary morphology in an unknown environment. The controller is modeled as a network of neural oscillators that are initially coupled only through physical embodiment, and goal-directed exploration of coordinated motor patterns is achieved by chaotic search using adaptive bifurcation. The phase space of the indirectly coupled neural-body-environment system contains multiple transient or permanent self-organized dynamics, each of which is a candidate for a locomotion behavior. The adaptive bifurcation enables the system orbit to wander through various phase-coordinated states, using its intrinsic chaotic dynamics as a driving force, and stabilizes on to one of the states matching the given goal criteria. In order to improve the sustainability of useful transient patterns, sensory homeostasis has been introduced, which results in an increased diversity of motor outputs, thus achieving multiscale exploration. A rhythmic pattern discovered by this process is memorized and sustained by changing the wiring between initially disconnected oscillators using an adaptive synchronization method. Our results show that the novel neurorobotic system is able to create and learn multiple locomotion behaviors for a wide range of body configurations and physical environments and can readapt in realtime after sustaining damage. PMID:22509965

  17. 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

  18. 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

  19. 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.

  20. 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

  1. Axial dynamics during locomotion in vertebrates lesson from the salamander.

    PubMed

    Cabelguen, Jean-Marie; Ijspeert, Auke; Lamarque, Stéphanie; Ryczko, Dimitri

    2010-01-01

    Much of what we know about the flexibility of the locomotor networks in vertebrates is derived from studies examining the adaptation of limb movements during stepping in various conditions. However, the body movements play important roles during locomotion: they produce the thrust during undulatory locomotion and they help to increase the stride length during legged locomotion. In this chapter, we review our current knowledge about the flexibility in the neuronal circuits controlling the body musculature during locomotion. We focus especially on salamander because, as an amphibian, this animal is able to display a rich repertoire of aquatic and terrestrial locomotor modes.

  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. The Need for Speed in Rodent Locomotion Analyses

    PubMed Central

    Batka, Richard J.; Brown, Todd J.; Mcmillan, Kathryn P.; Meadows, Rena M.; Jones, Kathryn J.; Haulcomb, Melissa M.

    2016-01-01

    Locomotion analysis is now widely used across many animal species to understand the motor defects in disease, functional recovery following neural injury, and the effectiveness of various treatments. More recently, rodent locomotion analysis has become an increasingly popular method in a diverse range of research. Speed is an inseparable aspect of locomotion that is still not fully understood, and its effects are often not properly incorporated while analyzing data. In this hybrid manuscript, we accomplish three things: (1) review the interaction between speed and locomotion variables in rodent studies, (2) comprehensively analyze the relationship between speed and 162 locomotion variables in a group of 16 wild-type mice using the CatWalk gait analysis system, and (3) develop and test a statistical method in which locomotion variables are analyzed and reported in the context of speed. Notable results include the following: (1) over 90% of variables, reported by CatWalk, were dependent on speed with an average R2 value of 0.624, (2) most variables were related to speed in a nonlinear manner, (3) current methods of controlling for speed are insufficient, and (4) the linear mixed model is an appropriate and effective statistical method for locomotion analyses that is inclusive of speed-dependent relationships. Given the pervasive dependency of locomotion variables on speed, we maintain that valid conclusions from locomotion analyses cannot be made unless they are analyzed and reported within the context of speed. PMID:24890845

  4. Industry review: Locomotive dynamic characterization test-analysis

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Data are given relative to tests performed on locomotive components. Dynamic characteristics related to safety are described. Suspension systems, shock absorbers, data processing, bearings, and damping are discussed.

  5. Memorial stone (R. Norris and Son Locomotive Works), level 270 ...

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

    Memorial stone (R. Norris and Son Locomotive Works), level 270 - Washington Monument, High ground West of Fifteenth Street, Northwest, between Independence & Constitution Avenues, Washington, District of Columbia, DC

  6. Simulation and robotics studies of salamander locomotion: applying neurobiological principles to the control of locomotion in robots.

    PubMed

    Ijspeert, Auke Jan; Crespi, Alessandro; Cabelguen, Jean-Marie

    2005-01-01

    This article presents a project that aims at understanding the neural circuitry controlling salamander locomotion, and developing an amphibious salamander-like robot capable of replicating its bimodal locomotion, namely swimming and terrestrial walking. The controllers of the robot are central pattern generator models inspired by the salamander's locomotion control network. The goal of the project is twofold: (1) to use robots as tools for gaining a better understanding of locomotion control in vertebrates and (2) to develop new robot and control technologies for developing agile and adaptive outdoor robots. The article has four parts. We first describe the motivations behind the project. We then present neuromechanical simulation studies of locomotion control in salamanders. This is followed by a description of the current stage of the robotic developments. We conclude the article with a discussion on the usefulness of robots in neuroscience research with a special focus on locomotion control.

  7. 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

  8. Guiding locomotion in complex, dynamic environments

    PubMed Central

    Fajen, Brett R.

    2013-01-01

    Locomotion in complex, dynamic environments is an integral part of many daily activities, including walking in crowded spaces, driving on busy roadways, and playing sports. Many of the tasks that humans perform in such environments involve interactions with moving objects—that is, they require people to coordinate their own movement with the movements of other objects. A widely adopted framework for research on the detection, avoidance, and interception of moving objects is the bearing angle model, according to which observers move so as to keep the bearing angle of the object constant for interception and varying for obstacle avoidance. The bearing angle model offers a simple, parsimonious account of visual control but has several significant limitations and does not easily scale up to more complex tasks. In this paper, I introduce an alternative account of how humans choose actions and guide locomotion in the presence of moving objects. I show how the new approach addresses the limitations of the bearing angle model and accounts for a variety of behaviors involving moving objects, including (1) choosing whether to pass in front of or behind a moving obstacle, (2) perceiving whether a gap between a pair of moving obstacles is passable, (3) avoiding a collision while passing through single or multiple lanes of traffic, (4) coordinating speed and direction of locomotion during interception, (5) simultaneously intercepting a moving target while avoiding a stationary or moving obstacle, and (6) knowing whether to abandon the chase of a moving target. I also summarize data from recent studies that support the new approach. PMID:23885238

  9. 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.

  10. Guiding locomotion in complex, dynamic environments.

    PubMed

    Fajen, Brett R

    2013-01-01

    Locomotion in complex, dynamic environments is an integral part of many daily activities, including walking in crowded spaces, driving on busy roadways, and playing sports. Many of the tasks that humans perform in such environments involve interactions with moving objects-that is, they require people to coordinate their own movement with the movements of other objects. A widely adopted framework for research on the detection, avoidance, and interception of moving objects is the bearing angle model, according to which observers move so as to keep the bearing angle of the object constant for interception and varying for obstacle avoidance. The bearing angle model offers a simple, parsimonious account of visual control but has several significant limitations and does not easily scale up to more complex tasks. In this paper, I introduce an alternative account of how humans choose actions and guide locomotion in the presence of moving objects. I show how the new approach addresses the limitations of the bearing angle model and accounts for a variety of behaviors involving moving objects, including (1) choosing whether to pass in front of or behind a moving obstacle, (2) perceiving whether a gap between a pair of moving obstacles is passable, (3) avoiding a collision while passing through single or multiple lanes of traffic, (4) coordinating speed and direction of locomotion during interception, (5) simultaneously intercepting a moving target while avoiding a stationary or moving obstacle, and (6) knowing whether to abandon the chase of a moving target. I also summarize data from recent studies that support the new approach. PMID:23885238

  11. 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

  12. 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.

  13. 49 CFR 229.141 - Body structure, MU locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... structure. (2) An anti-climbing arrangement shall be applied at each end that is designed so that coupled MU locomotives under full compression shall mate in a manner that will resist one locomotive from climbing the.... (2) An anti-climbing arrangement shall be applied at each end that is designed so that...

  14. 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...; overview. 92.104 Section 92.104 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures §...

  15. 40 CFR 92.104 - Locomotive and engine testing; overview.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... restriction within 1 inch of water of the upper limit of a typical engine as installed with clean air filters...; overview. 92.104 Section 92.104 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND LOCOMOTIVE ENGINES Test Procedures §...

  16. 49 CFR 223.11 - Requirements for existing locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of the Secretary of Transportation, 49 CFR 1.49(m)) ... be equipped with certified glazing in all locomotive cab windows after June 30, 1984. (d) Each... vandalism has a locomotive cab window that is broken or damaged so that the window fails to permit...

  17. 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.

  18. 49 CFR 229.121 - Locomotive cab noise.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...) 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...

  19. 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...

  20. 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

  1. 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

  2. 49 CFR 236.509 - Two or more locomotives coupled.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Two or more locomotives coupled. 236.509 Section..., INSPECTION, MAINTENANCE, AND REPAIR OF SIGNAL AND TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.509 Two or more locomotives...

  3. 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...

  4. 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…

  5. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ...-49A or suitably stenciled or tagged on the locomotive. (d) The amount of leakage from the equalizing... leakage is detected en route, the train may be moved only to the nearest forward location where the equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the...

  6. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...-49A or suitably stenciled or tagged on the locomotive. (d) The amount of leakage from the equalizing... leakage is detected en route, the train may be moved only to the nearest forward location where the equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the...

  7. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...-49A or suitably stenciled or tagged on the locomotive. (d) The amount of leakage from the equalizing... leakage is detected en route, the train may be moved only to the nearest forward location where the equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the...

  8. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...-49A or suitably stenciled or tagged on the locomotive. (d) The amount of leakage from the equalizing... leakage is detected en route, the train may be moved only to the nearest forward location where the equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the...

  9. 49 CFR 232.105 - General requirements for locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...-49A or suitably stenciled or tagged on the locomotive. (d) The amount of leakage from the equalizing... leakage is detected en route, the train may be moved only to the nearest forward location where the equalizing-reservoir leakage can be corrected. On locomotives equipped with electronic brakes, if the...

  10. EXTERIOR VIEW, RIGHT SIDE OF LOCOMOTIVE SHOWING WHEEL ASSEMBLY WITH ...

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

    EXTERIOR VIEW, RIGHT SIDE OF LOCOMOTIVE SHOWING WHEEL ASSEMBLY WITH BIG END OF MAIN ROD (TOP), ECCENTRIC CRANK (CENTER), AND BIG END CONCENTRIC ROD (BOTTOM). - Norfolk & Southern Steam Locomotive No. 611, Norris Yards, East of Ruffner Road, Irondale, Jefferson County, AL

  11. Underwater locomotion strategy by a benthic pennate diatom Navicula sp.

    PubMed

    Wang, Jiadao; Cao, Shan; Du, Chuan; Chen, Darong

    2013-10-01

    The mechanism of diatom locomotion has been widely researched but still remains a hypothesis. There are several questionable points on the prevailing model proposed by Edgar, and some of the observed phenomena cannot be completely explained by this model. In this paper, we undertook detailed investigations of cell structures, locomotion, secreted mucilage, and bending deformation for a benthic pennate diatom Navicula species. According to these broad evidences, an updated locomotion model is proposed. For Navicula sp., locomotion is realized via two or more pseudopods or stalks protruded out of the frustules. The adhesion can be produced due to the pull-off of one pseudopod or stalk from the substratum through extracellular polymeric substances. And the positive pressure is generated to balance the adhesion because of the push-down of another pseudopod or stalk onto the substratum. Because of the positive pressure, friction is generated, acting as a driving force of locomotion, and the other pseudopod or stalk can detach from the substratum, resulting in the locomotion. Furthermore, this model is validated by the force evaluation and can better explain observed phenomena. This updated model would provide a novel aspect on underwater locomotion strategy, hence can be useful in terms of artificial underwater locomotion devices.

  12. Instability-induced hierarchy in bipedal locomotion

    NASA Astrophysics Data System (ADS)

    Ohgane, Kunishige; Ueda, Kei-Ichi

    2008-05-01

    One of the important features of human locomotion is its instant adaptability to various unpredictable changes of physical and environmental conditions. This property is known as flexibility. Modeling the bipedal locomotion system, we show that initial-state coordination by a global variable which encodes the attractor basins of the system can yield flexibility. This model is based on the following hypotheses: (i) the walking velocity is a global variable, and (ii) the leg posture at the beginning of the stance phase is the initial state of the gait. Moreover, we confirm these hypotheses. We investigate the regions near the neutral states between walking and falling phases using numerical experiments and demonstrate that global variables can be defined as the dominant unstable directions of the system dynamics near the neutral states. We propose the concept of an “instability-induced hierarchy.” In this hierarchy, global variables govern other variables near neutral states; i.e., they become elements of a higher level.

  13. Reversibility in locomotion in granular media

    NASA Astrophysics Data System (ADS)

    Savoie, William; Goldman, Daniel

    2013-11-01

    A recent study of a self-deforming robot [Hatton et al., PRL, 2013] demonstrated that slow movement in dry granular media resembles locomotion in low Re fluids, in part because inertia is dominated by friction. The study indicated that granular swimming was kinematically reversible, a surprise because yielding in granular flow is irreversible. To investigate if reciprocal motions lead to net displacements in granular swimmers, in laboratory experiments, we study the locomotion of a robotic ``scallop'' consisting of a square body with two flipper-like limbs controlled to flap forward and backward symmetrically (a flap cycle). The body is constrained by linear bearings to allow motion in only one dimension. We vary the the flapping frequency f, the body/flipper burial depth d, and the number of flaps N in a deep bed of 6 mm diameter plastic spheres. Over a range of f and d, the N = 1 cycle produces net translation of the body; however for large N, a cycle produces no net translation. We conclude that symmetric strokes in granular swimming are irreversible at the onset of self-deformation, but become asymptotically reversible. work supported by NSF and ARL.

  14. Turning and maneuverability during sidewinding locomotion

    NASA Astrophysics Data System (ADS)

    Astley, Henry; Goldman, Daniel; Hu, David

    2014-03-01

    Sidewinding is an unusual form of snake locomotion used to move rapidly on yielding substrates such as desert sands. Posteriorly propagating waves alternate between static contact with the substrate and elevated motion, resulting in a ``stepping'' motion of body segments. Unlike lateral undulation, the direction of travel is not collinear with the axis of the body wave, and posterior body segments do not follow the path of anterior segments. Field observations indicate that sidewinding snakes are highly maneuverable, but the mechanisms by which these snakes change direction during this complex movement are unknown. Motion capture data from three Colorado Desert sidewinder rattlesnakes (Crotalus cerastes laterorepens) shows a variety of turn magnitudes and behaviors. Additionally, sidewinders are capable of ``reversals'' in which the snakes halts forward progress and begins locomotion in the opposite direction without rotation of the body. Because the head is re-oriented with respect to the body during these reversals, the snake is able to reverse direction without rotation yet continue moving in the new direction without impediment to perception or mechanics, a rare level of maneuverability in animals.

  15. A Review of Locomotion Systems for Capsule Endoscopy.

    PubMed

    Liu, Lejie; Towfighian, Shahrzad; Hila, Amine

    2015-01-01

    Wireless capsule endoscopy for gastrointestinal (GI) tract is a modern technology that has the potential to replace conventional endoscopy techniques. Capsule endoscopy is a pill-shaped device embedded with a camera, a coin battery, and a data transfer. Without a locomotion system, this capsule endoscopy can only passively travel inside the GI tract via natural peristalsis, thus causing several disadvantages such as inability to control and stop, and risk of capsule retention. Therefore, a locomotion system needs to be added to optimize the current capsule endoscopy. This review summarizes the state-of-the-art locomotion methods along with the desired locomotion features such as size, speed, power, and temperature and compares the properties of different methods. In addition, properties and motility mechanisms of the GI tract are described. The main purpose of this review is to understand the features of GI tract and diverse locomotion methods in order to create a future capsule endoscopy compatible with GI tract properties. PMID:26292162

  16. 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.

  17. Reduction and identification for hybrid dynamical models of terrestrial locomotion

    NASA Astrophysics Data System (ADS)

    Burden, Samuel A.; Sastry, S. Shankar

    2013-06-01

    The study of terrestrial locomotion has compelling applications ranging from design of legged robots to development of novel prosthetic devices. From a first-principles perspective, the dynamics of legged locomotion seem overwhelmingly complex as nonlinear rigid body dynamics couple to a granular substrate through viscoelastic limbs. However, a surfeit of empirical data demonstrates that animals use a small fraction of their available degrees-of-freedom during locomotion on regular terrain, suggesting that a reduced-order model can accurately describe the dynamical variation observed during steady-state locomotion. Exploiting this emergent phenomena has the potential to dramatically simplify design and control of micro-scale legged robots. We propose a paradigm for studying dynamic terrestrial locomotion using empirically-validated reduced{order models.

  18. 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.

  19. 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 1242.60 Transportation Other Regulations Relating to Transportation (Continued) SURFACE TRANSPORTATION BOARD, DEPARTMENT OF TRANSPORTATION...

  20. 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.

  1. 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.

  2. A Capillarity Mechanism for Diatom Gliding Locomotion

    PubMed Central

    Gordon, Richard; Drum, Ryan W.

    1970-01-01

    It is proposed that the diatom raphe is a parallel-plate capillary containing a fluid which reacts at the trailing end, turning into a form which no longer „wets” the raphe walls, and which is left behind as a trail. More unreacted raphe fluid is drawn by capillary pressure from a source near the leading end of the raphe. This fluid sticks out from the raphe along its length, adhering to surfaces, thus causing gliding locomotion. Formulae are given for the maximum velocity and force of a moving diatom in terms of the raphe dimensions and the surface tension and viscosity of the fluid. An a priori estimate of the force exerted by a moving diatom, 1-50 millidynes, agrees with measured values. Five experimental tests of the theory are proposed. PMID:16591861

  3. 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.

  4. 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.

  5. Active control of locomotion facilitates nonvisual navigation.

    PubMed

    Philbeck, J W; Klatzky, R L; Behrmann, M; Loomis, J M; Goodridge, J

    2001-02-01

    In some navigation tasks, participants are more accurate if they view the environment beforehand. To characterize the benefits associated with visual previews, 32 blindfolded participants were guided along simple paths and asked to walk unassisted to a specified destination (e.g., the origin). Paths were completed without vision, with or without a visual preview of the environment. Previews did not necessarily improve nonvisual navigation. When previewed landmarks stood near the origin or at off-path locations, they provided little benefit; by contrast, when they specified intermediate destinations (thereby increasing the degree of active control), performance was greatly enhanced. The results suggest that the benefit of a visual preview stems from the information it supplies for actively controlled locomotion. Accuracy in reaching the final destination, however, is strongly contingent upon the destination's location during the preview.

  6. Intraoperative bowel cleansing tool in active locomotion capsule endoscopy.

    PubMed

    Ciuti, G; Tognarelli, S; Verbeni, A; Menciassi, A; Dario, P

    2013-01-01

    Capsule endoscopy (CE) can be considered an example of "disruptive technology" since it represents a bright alternative to traditional diagnostic methodologies. If compared with traditional endoscopy, bowel cleansing procedure in CE becomes of greater importance, due to the impossibility to intraoperatively operate on unclean gastrointestinal tract areas. Considering the promising results and benefits obtained in the field of CE for gastrointestinal diagnosis and intervention, the authors approached the bowel cleansing issue with the final aim to propose an innovative and easy-to-use intraoperative cleansing system to be applied to an active locomotion softly-tethered capsule device, already developed by the authors. The system, that has to be intended as an additional tool for intraoperatively cleansing procedure of the colonic tract, is composed by a flexible tube with a metallic deflector attached to the distal end; it can be headed to the target area through the capsule operating channel. Performances of the colonoscopic capsule and intraoperative cleansing capabilities were successfully confirmed both in an in-vitro and ex-vivo experimental session. The innovative intraoperative cleansing system demonstrated promising results in terms of water injection, colonic wall cleansing procedure and subsequent water suction, thus guaranteeing to reduce the risk of inadequate visualization of the mucosa in endoscopic procedures. PMID:24110819

  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. 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.

  9. 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.

  10. [Mild cognitive disorders in railway locomotive crew workers (review of literature)].

    PubMed

    Ozhogina, O A; Zakrevskaya, A A; Serikov, V V

    2016-01-01

    Functional reliability of engine operator and engine operator's assistant is one of the most important factors in railway safety. Ability to railway locomotive operation is determined via suitability criteria of occupationally important qualities of operator and operator's assistant, and of nervous system functional state. Lower reliability manifested in worse functional state of engine operator or in lost occupationally important qualities can be connected with various diseases of which most prevalent are cardiovascular disorders. Transitory brain circulatory disorders can cause cognitive disturbances varying in severity. When mild cognitive disorders, precise diagnosis leads to effective prevention of the diseases development and preserved occupationally important qualities in engine operators. Neuropsychologic methods for mild cognitive disorders help not only to diagnose presence and intensity of cognitive defect, but to suggest a mechanism of its development, that eventually increases efficiency of correction. PMID:27396149

  11. [Mild cognitive disorders in railway locomotive crew workers (review of literature)].

    PubMed

    Ozhogina, O A; Zakrevskaya, A A; Serikov, V V

    2016-01-01

    Functional reliability of engine operator and engine operator's assistant is one of the most important factors in railway safety. Ability to railway locomotive operation is determined via suitability criteria of occupationally important qualities of operator and operator's assistant, and of nervous system functional state. Lower reliability manifested in worse functional state of engine operator or in lost occupationally important qualities can be connected with various diseases of which most prevalent are cardiovascular disorders. Transitory brain circulatory disorders can cause cognitive disturbances varying in severity. When mild cognitive disorders, precise diagnosis leads to effective prevention of the diseases development and preserved occupationally important qualities in engine operators. Neuropsychologic methods for mild cognitive disorders help not only to diagnose presence and intensity of cognitive defect, but to suggest a mechanism of its development, that eventually increases efficiency of correction.

  12. 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.

  13. 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...

  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, 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...

  16. 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...

  17. 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...

  18. [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. PMID:27396147

  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. FIM, a Novel FTIR-Based Imaging Method for High Throughput Locomotion Analysis

    PubMed Central

    Otto, Nils; Löpmeier, Tim; Valkov, Dimitar; Jiang, Xiaoyi; Klämbt, Christian

    2013-01-01

    We designed a novel imaging technique based on frustrated total internal reflection (FTIR) to obtain high resolution and high contrast movies. This FTIR-based Imaging Method (FIM) is suitable for a wide range of biological applications and a wide range of organisms. It operates at all wavelengths permitting the in vivo detection of fluorescent proteins. To demonstrate the benefits of FIM, we analyzed large groups of crawling Drosophila larvae. The number of analyzable locomotion tracks was increased by implementing a new software module capable of preserving larval identity during most collision events. This module is integrated in our new tracking program named FIMTrack which subsequently extracts a number of features required for the analysis of complex locomotion phenotypes. FIM enables high throughput screening for even subtle behavioral phenotypes. We tested this newly developed setup by analyzing locomotion deficits caused by the glial knockdown of several genes. Suppression of kinesin heavy chain (khc) or rab30 function led to contraction pattern or head sweeping defects, which escaped in previous analysis. Thus, FIM permits forward genetic screens aimed to unravel the neural basis of behavior. PMID:23349775

  1. 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.

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

    PubMed

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

    2014-07-01

    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. PMID:24812661

  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. PMID:24030051

  4. 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.

  5. Synaptic representation of locomotion in single cerebellar granule cells

    PubMed Central

    Powell, Kate; Mathy, Alexandre; Duguid, Ian; Häusser, Michael

    2015-01-01

    The cerebellum plays a crucial role in the regulation of locomotion, but how movement is represented at the synaptic level is not known. Here, we use in vivo patch-clamp recordings to show that locomotion can be directly read out from mossy fiber synaptic input and spike output in single granule cells. The increase in granule cell spiking during locomotion is enhanced by glutamate spillover currents recruited during movement. Surprisingly, the entire step sequence can be predicted from input EPSCs and output spikes of a single granule cell, suggesting that a robust gait code is present already at the cerebellar input layer and transmitted via the granule cell pathway to downstream Purkinje cells. Thus, synaptic input delivers remarkably rich information to single neurons during locomotion. DOI: http://dx.doi.org/10.7554/eLife.07290.001 PMID:26083712

  6. 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

  7. 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

  8. 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.

  9. 6. Photocopy of drawing, January 28, 1920. LOCOMOTIVE: ELEVATIONS AND ...

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

    6. Photocopy of drawing, January 28, 1920. LOCOMOTIVE: ELEVATIONS AND TYPICAL SECTION. Watertown Arsenal Engineering Division, Drawing Number 10453. (Original: AMTL Engineering Division, Watertown). - Watertown Arsenal, Building No. 97, Wooley Avenue, Watertown, Middlesex County, MA

  10. 7. STRUCTURAL DETAILS AT ENTRANCE OF LOCOMOTIVE ROUNDHOUSE, SHEET NO. ...

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

    7. STRUCTURAL DETAILS AT ENTRANCE OF LOCOMOTIVE ROUNDHOUSE, SHEET NO. 1-9-2/89.1 (DRAWING DATED 1942). - Oakland Army Base, Railroad Engine Shop, Engineer Road & Wake Avenue, Oakland, Alameda County, CA

  11. 49 CFR 229.15 - Remote control locomotives.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...'s having the capability to control more than one RCL shall have a means to lock in one RCL... eliminate tractive effort to the locomotive; (xi) Audio/visual indication of wheel slip, only if an...

  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. 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 §...

  14. 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 §...

  15. 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 §...

  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. 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

  18. 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

  19. Expression of emotion in the kinematics of locomotion.

    PubMed

    Barliya, Avi; Omlor, Lars; Giese, Martin A; Berthoz, Alain; Flash, Tamar

    2013-03-01

    Here, we examine how different emotions-happiness, fear, sadness and anger-affect the kinematics of locomotion. We focus on a compact representation of locomotion properties using the intersegmental law of coordination (Borghese et al. in J Physiol 494(3):863-879, 1996), which states that, during the gait cycle of human locomotion, the elevation angles of the thigh, shank and foot do not evolve independently of each other but form a planar pattern of co-variation. This phenomenon is highly robust and has been extensively studied. The orientation of the plane has been correlated with changes in the speed of locomotion and with reduction in energy expenditure as speed increases. An analytical model explaining the conditions underlying the emergence of this plane and predicting its orientation reveals that it suffices to examine the amplitudes of the elevation angles of the different segments along with the phase shifts between them (Barliya et al. in Exp Brain Res 193:371-385, 2009). We thus investigated the influence of different emotions on the parameters directly determining the orientation of the intersegmental plane and on the angular rotation profiles of the leg segments, examining both the effect of changes in walking speed and effects independent of speed. Subjects were professional actors and naïve subjects with no training in acting. As expected, emotions were found to strongly affect the kinematics of locomotion, particularly walking speed. The intersegmental coordination patterns revealed that emotional expression caused additional modifications to the locomotion patterns that could not be explained solely by a change in speed. For all emotions except sadness, the amplitude of thigh elevation angles changed from those in neutral locomotion. The intersegmental plane was also differently oriented, especially during anger. We suggest that, while speed is the dominant variable allowing discrimination between different emotional gaits, emotion can be

  20. The Kinematics of Treadmill Locomotion in Space

    NASA Technical Reports Server (NTRS)

    Thornton, W. E.; Cavanagh, P. R.; Buczek, F. L.; Burgess-Milliron, M. J.; Davis, B. L.

    1997-01-01

    Locomotion on a treadmill in 0 G will probably remain a centerpiece of NASA's exercise countermeasures programme. This form of physical activity has the potential to cause large bone and muscle forces as well as loading during a period of continuous treadmill exercise. A critical concern is the provision of a treadmill which can approximate 1 G performance in space. At this point, no adequate objective measurements of in-flight treadmill kinetics or of the human response to this activity have been made. Interpretation of the results obtained in the present study is limited by the following: (1) bungee tensions were not measured; (2) ground reaction forces were not measured in parallel with the kinematic measurements; and (3) the instrumentation used to film the astronauts could itself have been affected by microgravity. Despite these shortcomings, what is apparent is that exercise during NASA missions STS 7 and STS 8 resulted in leg motions that were similar to those found during 1 G locomotion on an inclined passive treadmill and on an active treadmill at an even steeper grade. In addition, it was apparent that the majority of the loads were transmitted through the forefoot, and one can surmise that this style of running would result in physiologically significant tensions in the calf musculature and resultant ankle compressive loading. Further speculation regarding limb loading is complicated by the fact that varying amounts of force are transmitted through (1) the treadmill handle and (2) bungee cords that act as a tether. New generations of treadmills are being manufactured that could provide I important information for planners of long-duration space missions. If these types of treadmill are flown on future missions, it will be possible to control bungee tensions more precisely, control for grade and speed, and, most importantly, provide data on the rates and magnitudes of limb loading. These data could then be incorporated into biomechanical models of the

  1. Serotonin influences locomotion in the nudibranch mollusc Melibe leonina.

    PubMed

    Lewis, Stefanie L; Lyons, Deborah E; Meekins, Tiffanie L; Newcomb, James M

    2011-06-01

    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

  2. Mechanics of peristaltic locomotion and role of anchoring

    PubMed Central

    Tanaka, Yoshimi; Ito, Kentaro; Nakagaki, Toshiyuki; Kobayashi, Ryo

    2012-01-01

    Limbless crawling is a fundamental form of biological locomotion adopted by a wide variety of species, including the amoeba, earthworm and snake. An interesting question from a biomechanics perspective is how limbless crawlers control their flexible bodies in order to realize directional migration. In this paper, we discuss the simple but instructive problem of peristalsis-like locomotion driven by elongation–contraction waves that propagate along the body axis, a process frequently observed in slender species such as the earthworm. We show that the basic equation describing this type of locomotion is a linear, one-dimensional diffusion equation with a time–space-dependent diffusion coefficient and a source term, both of which express the biological action that drives the locomotion. A perturbation analysis of the equation reveals that adequate control of friction with the substrate on which locomotion occurs is indispensable in order to translate the internal motion (propagation of the elongation–contraction wave) into directional migration. Both the locomotion speed and its direction (relative to the wave propagation) can be changed by the control of friction. The biological relevance of this mechanism is discussed. PMID:21831891

  3. 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

  4. Activity of motor cortex neurons during backward locomotion.

    PubMed

    Zelenin, P V; Deliagina, T G; Orlovsky, G N; Karayannidou, A; Stout, E E; Sirota, M G; Beloozerova, I N

    2011-06-01

    Forward walking (FW) and backward walking (BW) are two important forms of locomotion in quadrupeds. Participation of the motor cortex in the control of FW has been intensively studied, whereas cortical activity during BW has never been investigated. The aim of this study was to analyze locomotion-related activity of the motor cortex during BW and compare it with that during FW. For this purpose, we recorded activity of individual neurons in the cat during BW and FW. We found that the discharge frequency in almost all neurons was modulated in the rhythm of stepping during both FW and BW. However, the modulation patterns during BW and FW were different in 80% of neurons. To determine the source of modulating influences (forelimb controllers vs. hindlimb controllers), the neurons were recorded not only during quadrupedal locomotion but also during bipedal locomotion (with either forelimbs or hindlimbs walking), and their modulation patterns were compared. We found that during BW (like during FW), modulation in some neurons was determined by inputs from limb controllers of only one girdle, whereas the other neurons received inputs from both girdles. The combinations of inputs could depend on the direction of locomotion. Most often (in 51% of forelimb-related neurons and in 34% of the hindlimb-related neurons), the neurons received inputs only from their own girdle when this girdle was leading and from both girdles when this girdle was trailing. This reconfiguration of inputs suggests flexibility of the functional roles of individual cortical neurons during different forms of locomotion.

  5. 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.

  6. Visualizing the spinal neuronal dynamics of locomotion

    NASA Astrophysics Data System (ADS)

    Subramanian, Kalpathi R.; Bashor, D. P.; Miller, M. T.; Foster, J. A.

    2004-06-01

    Modern imaging and simulation techniques have enhanced system-level understanding of neural function. In this article, we present an application of interactive visualization to understanding neuronal dynamics causing locomotion of a single hip joint, based on pattern generator output of the spinal cord. Our earlier work visualized cell-level responses of multiple neuronal populations. However, the spatial relationships were abstract, making communication with colleagues difficult. We propose two approaches to overcome this: (1) building a 3D anatomical model of the spinal cord with neurons distributed inside, animated by the simulation and (2) adding limb movements predicted by neuronal activity. The new system was tested using a cat walking central pattern generator driving a pair of opposed spinal motoneuron pools. Output of opposing motoneuron pools was combined into a single metric, called "Net Neural Drive", which generated angular limb movement in proportion to its magnitude. Net neural drive constitutes a new description of limb movement control. The combination of spatial and temporal information in the visualizations elegantly conveys the neural activity of the output elements (motoneurons), as well as the resulting movement. The new system encompasses five biological levels of organization from ion channels to observed behavior. The system is easily scalable, and provides an efficient interactive platform for rapid hypothesis testing.

  7. 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. PMID:21748447

  8. 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.

  9. 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.

  10. Locomotion of granulocytes on an inclined plane.

    PubMed

    Doroszewski, J; Lewandowska, K; Wierzbicki, W

    1986-01-01

    The paper presents a quantitative study of the trajectories of rat granulocytes (PMNs) migrating on a glass surface inclined at various angles, i.e. under the action of gravitational force component parallel to the plane. The action of the force of the order of 5 X 10(-13) N (component parallel to the plane inclined at 80 degrees) accompanied by the decrease of a gravitational component perpendicular to the surface does not disrupt the adhesion contact of migrating PMNs with the serum coated glass surface. Under the action of the external force parallel to the surface, the PMNs exhibit a tendency to migrate in the direction of the force vector and the angles between elementary segments (steps) of cell trajectories are smaller in comparison with migration on a horizontal plane (0 degrees inclination). It has been found that the mean velocity of motion of PMNs locomoting on a steep slope (70 degrees and 80 degrees) is greater in comparison with the migration velocity on a horizontal surface. The increase of velocity concerns not only cells migrating in the downward direction, but also those which move upwards. Possible mechanisms of the influence of external force on direction and rate of migration of granulocytes are discussed, namely modification of adhesion force, stimulation of cell motile activity, individual variability of cell adhesive and migration properties, shortening of transient locomotory adhesions.

  11. 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. PMID:21708701

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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...

  17. 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...

  18. 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...

  19. 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...

  20. 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...

  1. 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.

  2. Stabilization of cat paw trajectory during locomotion.

    PubMed

    Klishko, Alexander N; Farrell, Bradley J; Beloozerova, Irina N; Latash, Mark L; Prilutsky, Boris I

    2014-09-15

    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

  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. Cytoskeletal Mechanics Regulating Amoeboid Cell Locomotion

    PubMed Central

    Álvarez-González, Begoña; Meili, Ruedi; Firtel, Richard; Bastounis, Effie; del Álamo, Juan C.; Lasheras, Juan C.

    2014-01-01

    Migrating cells exert traction forces when moving. Amoeboid cell migration is a common type of cell migration that appears in many physiological and pathological processes and is performed by a wide variety of cell types. Understanding the coupling of the biochemistry and mechanics underlying the process of migration has the potential to guide the development of pharmacological treatment or genetic manipulations to treat a wide range of diseases. The measurement of the spatiotemporal evolution of the traction forces that produce the movement is an important aspect for the characterization of the locomotion mechanics. There are several methods to calculate the traction forces exerted by the cells. Currently the most commonly used ones are traction force microscopy methods based on the measurement of the deformation induced by the cells on elastic substrate on which they are moving. Amoeboid cells migrate by implementing a motility cycle based on the sequential repetition of four phases. In this paper we review the role that specific cytoskeletal components play in the regulation of the cell migration mechanics. We investigate the role of specific cytoskeletal components regarding the ability of the cells to perform the motility cycle effectively and the generation of traction forces. The actin nucleation in the leading edge of the cell, carried by the ARP2/3 complex activated through the SCAR/WAVE complex, has shown to be fundamental to the execution of the cyclic movement and to the generation of the traction forces. The protein PIR121, a member of the SCAR/WAVE complex, is essential to the proper regulation of the periodic movement and the protein SCAR, also included in the SCAR/WAVE complex, is necessary for the generation of the traction forces during migration. The protein Myosin II, an important F-actin cross-linker and motor protein, is essential to cytoskeletal contractility and to the generation and proper organization of the traction forces during

  5. Organisational factors and scheduling in locomotive engineers and conductors: Effects on fatigue, health and social well-being.

    PubMed

    Ku, Chia-Hua; Smith, Michael J

    2010-01-01

    This study examines critical organisational factors and work scheduling in railway freight operators to understand how job-related factors are related to fatigue, health and social well-being. A 148-item questionnaire was developed and distributed to a sample of 276 locomotive engineers and conductors working for the U.S. Operations of a North American Railway. One hundred and twenty-five questionnaires were returned, which was a response rate of 45.3%. Structural equation modeling was performed to identify the relationships between the examined factors. The analytical results of this study indicate that organisational factors and the scheduling system could not be distinguished as two separate factors. The scheduling system is not just the practice of assigning locomotive crewmen to trains, but it is a function tightly connected with other organisational factors. Social Well-Being is an important mediator between Scheduling and Fatigue. Finally, the study revealed a strong relationship between fatigue and health complaints.

  6. 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.

  7. Small Step or Giant Leap - Human Locomotion on Mars

    NASA Astrophysics Data System (ADS)

    Hawkey, A.

    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 1g, 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.

  8. 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. PMID:18185840

  9. 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.

  10. Gait transitions during unrestrained locomotion in dogs.

    PubMed

    Blaszczyk, J W

    2001-04-01

    Gait transitions during long distance, unrestrained locomotion were studied in 22 mongrel dogs. Spatial and temporal limb movement parameters were collected and the phase relationships between limb movements based upon a 2-dimensional (2-D) gait diagram were computed. During most of the trials, the dogs trotted within a relatively narrow velocity range. Gait transitions were observed during radical changes of the movement velocity. In most cases the gait switches were abrupt and completed within 2 strides of the gait cycle. The dogs walked, depending on the animal size, within the upper velocity range of 0.93-1.21 m/s. Most of the walk-trot transitions were observed within this range. All of them had a typical pattern that involved changes of the phase shift between diagonal limb movements from 0.31 +/- 0.02 (a typical value for a walking dog) down to 0.02 +/- 0.03. These changes appeared abruptly within one stride cycle for each diagonal pair of limbs; therefore, the transition was completed in 2 strides of the gait cycle. The switch involved momentary shortening of the hindlimb amplitudes. During the next gait cycle, all limb movement amplitudes were reduced with a concomitant increase in limb movement frequencies. In contrast to the clear border between the symmetrical gaits, the dogs switched to gallop at any speed within the trot range (most frequently between 1.5-2.6 m/s). The transitions were usually completed within one stride of the diagonal limbs. In most cases, the switch from trot to gallop had a similar pattern; while maintaining synchronous movement of one diagonal pair of limbs, the other pair movement control was modified accordingly. The typical transition pattern involved the shortening of the swing phase in the front limb with simultaneous lengthening of the swing phase in the diagonal hindlimb. These transient modifications had their equivalent in the analogous limb movement amplitude changes. A mirror-image pattern of phase changes was observed

  11. Quantifying coordination between the head and the trunk during locomotion

    NASA Astrophysics Data System (ADS)

    Mulavara, Ajitkumar P.

    This study developed unique measures of coordination between the head and the trunk during the combined tasks of locomotion and gaze fixation of visual targets. These measures will be used to determine the effects of long-duration space flight on sensorimotor function. This will enable evaluation of the efficacy of countermeasures and postflight rehabilitation programs. Indices were proposed as composite measures reflecting the functional aspects of the control system involved in gaze fixation during locomotion. The stiffness index (Nm/deg) was calculated as the ratio between the change in the magnitude of the net relative moments to the change in magnitude of the relative angular motion. The viscosity index (Nm-sec/deg) was calculated as the ratio between the change in the magnitude of the net relative moments to the change in magnitude of the relative angular velocity. These coordination measures were used to evaluate the normal dynamic pattern of coordination between the head and the trunk with respect to the events occurring in a gait cycle. The indices were evaluated for three discrete speeds of locomotion for the same gaze fixation task and for three discrete gaze fixation tasks at the same speed of locomotion. The indices were found to be repeatable measures reflecting inter-segmental coordination strategies while performing an activity of daily living. These indices showed that the coordination of the head with respect to the trunk was significantly different between the events of heel strike and swing phases during the gait cycle. These indices showed no significant differences between the different gaze fixation tasks. The speed of locomotion had a significant effect on the magnitude of these indices. The results indicate that the CNS dynamically modulates head motion with respect to the trunk dependent on the events occurring during the gait cycle. This modulation is appropriate for stabilizing gaze during locomotion. The results support the hypothesis

  12. Insects Use Two Distinct Classes of Steps during Unrestrained Locomotion

    PubMed Central

    Theunissen, Leslie M.; Dürr, Volker

    2013-01-01

    Background Adaptive, context-dependent control of locomotion requires modulation of centrally generated rhythmic motor patterns through peripheral control loops and postural reflexes. Thus assuming that the modulation of rhythmic motor patterns accounts for much of the behavioural variability observed in legged locomotion, investigating behavioural variability is a key to the understanding of context-dependent control mechanisms in locomotion. To date, the variability of unrestrained locomotion is poorly understood, and virtually nothing is known about the features that characterise the natural statistics of legged locomotion. In this study, we quantify the natural variability of hexapedal walking and climbing in insects, drawing from a database of several thousand steps recorded over two hours of walking time. Results We show that the range of step length used by unrestrained climbing stick insects is large, showing that step length can be changed substantially for adaptive locomotion. Step length distributions were always bimodal, irrespective of leg type and walking condition, suggesting the presence of two distinct classes of steps: short and long steps. Probability density of step length was well-described by a gamma distribution for short steps, and a logistic distribution for long steps. Major coefficients of these distributions remained largely unaffected by walking conditions. Short and long steps differed concerning their spatial occurrence on the walking substrate, their timing within the step sequence, and their prevalent swing direction. Finally, ablation of structures that serve to improve foothold increased the ratio of short to long steps, indicating a corrective function of short steps. Conclusions Statistical and functional differences suggest that short and long steps are physiologically distinct classes of leg movements that likely reflect distinct control mechanisms at work. PMID:24376877

  13. 40 CFR 1033.15 - Other regulation parts that apply for locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... chapter apply to everyone, including anyone who manufactures, remanufactures, imports, maintains, owns, or... and others. (2) Exclusions and exemptions for certain locomotives. (3) Importing locomotives. (4) Selective enforcement audits of your production. (5) Defect reporting and recall. (6) Procedures...

  14. 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.

  15. 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.

  16. Cells can use their transferrin receptors for locomotion.

    PubMed Central

    Bretscher, M S

    1992-01-01

    Cells of the B lymphoblastoid cell line JY attach to substrata made of antibodies to the transferrin receptor. Many of these attached cells migrate considerable distances. JY cells also attach to an anti-integrin substratum (anti LFA-1), but on this surface they do not migrate. These results suggest that a circulating receptor--the transferrin receptor--can be used for locomotory purposes, whereas LFA-1, which is not endocytosed in these cells, cannot be used for locomotion. This indicates that the endocytotic cycle can drive cell locomotion. Images PMID:1537325

  17. Locomotion of the blind controlled by natural sound cues.

    PubMed

    Strelow, E R; Brabyn, J A

    1982-01-01

    Measures of the accuracy of locomotion control were taken with blind and blindfolded sighted subjects using the natural auditory obstacle sense to locate a travel path. These measures were compared with the accuracy of visual guidance. While the blind show a greater skill than blindfolded sighted subjects in using auditory cues for guidance, auditory guidance is notably inferior to visual guidance and deteriorates markedly when smaller targets are used to define the travel path. The natural obstacle sense thus appears to give only a rudimentary perception of the presence of objects and does not provide sufficient spatial information to allow accurate locomotion control.

  18. Development of a locomotive engine condition monitoring system

    SciTech Connect

    Broughton, C.; Holloway, R.; Webster, G.

    1997-12-31

    Outlines test procedures and results of a study of the application of the instantaneous crankshaft angular velocity (ICAV) engine condition monitoring system applied to three freight locomotives. The study involved the assessment of a prototype repair-shop diagnostic tool, based on prior experimental programs and the ICAV technology. Engine testing was carried out at four-month intervals for three separate trials on the locomotives. Experimental data obtained included power output, fuel consumption, cylinder firing pressure waveforms, and the ICAV waveforms. The performance of the ICAV system was judged on its ability to accurately predict the change in indicated mean effective pressure of each cylinder from one test to the next.

  19. 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.

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Special Compliance Provisions § 1033... 3000 hp may not generate emission credits relative to the standards specified in paragraph (e)(1)(i) of...: “REFURBISHED LOCOMOTIVE EMISSION CONTROL INFORMATION.” (ii) The statement identifying when the locomotive...

  2. 40 CFR 1033.420 - Maintenance, procurement and testing of in-use locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES In-use Testing § 1033.420... recommended emission-related maintenance requirements. (1) When procuring locomotives for in-use testing, ask... adjustments. (c) If the locomotive selected for testing is equipped with emission diagnostics meeting...

  3. 49 CFR 222.21 - When must a locomotive horn be used?

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION USE OF LOCOMOTIVE HORNS AT PUBLIC HIGHWAY-RAIL GRADE CROSSINGS Use...-rail grade crossing. Sounding of the locomotive horn with two long blasts, one short blast and one long... shall be repeated or prolonged until the locomotive occupies the crossing. This pattern may be varied...

  4. 49 CFR 222.21 - When must a locomotive horn be used?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION USE OF LOCOMOTIVE HORNS AT PUBLIC HIGHWAY-RAIL GRADE CROSSINGS Use...-rail grade crossing. Sounding of the locomotive horn with two long blasts, one short blast and one long... shall be repeated or prolonged until the locomotive occupies the crossing. This pattern may be varied...

  5. 49 CFR 222.21 - When must a locomotive horn be used?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION USE OF LOCOMOTIVE HORNS AT PUBLIC HIGHWAY-RAIL GRADE CROSSINGS Use...-rail grade crossing. Sounding of the locomotive horn with two long blasts, one short blast and one long... shall be repeated or prolonged until the locomotive occupies the crossing. This pattern may be varied...

  6. 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...

  7. 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...

  8. 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...

  9. 49 CFR 240.105 - Criteria for selection of designated supervisors of locomotive engineers.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... of locomotive engineers. 240.105 Section 240.105 Transportation Other Regulations Relating to... CERTIFICATION OF LOCOMOTIVE ENGINEERS Component Elements of the Certification Process § 240.105 Criteria for selection of designated supervisors of locomotive engineers. (a) Each railroad's program shall...

  10. 49 CFR 240.105 - Criteria for selection of designated supervisors of locomotive engineers.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... of locomotive engineers. 240.105 Section 240.105 Transportation Other Regulations Relating to... CERTIFICATION OF LOCOMOTIVE ENGINEERS Component Elements of the Certification Process § 240.105 Criteria for selection of designated supervisors of locomotive engineers. (a) Each railroad's program shall...

  11. 49 CFR 1242.25 - Locomotive servicing facilities (account XX-19-27).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Locomotive servicing facilities (account XX-19-27... Structures § 1242.25 Locomotive servicing facilities (account XX-19-27). Separate common expenses according to distribution of common expenses in the following accounts: Locomotive Fuel (XX-51-67 and...

  12. 49 CFR 1242.25 - Locomotive servicing facilities (account XX-19-27).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 9 2012-10-01 2012-10-01 false Locomotive servicing facilities (account XX-19-27... Structures § 1242.25 Locomotive servicing facilities (account XX-19-27). Separate common expenses according to distribution of common expenses in the following accounts: Locomotive Fuel (XX-51-67 and...

  13. 49 CFR 1242.25 - Locomotive servicing facilities (account XX-19-27).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 9 2011-10-01 2011-10-01 false Locomotive servicing facilities (account XX-19-27... Structures § 1242.25 Locomotive servicing facilities (account XX-19-27). Separate common expenses according to distribution of common expenses in the following accounts: Locomotive Fuel (XX-51-67 and...

  14. 49 CFR 1242.25 - Locomotive servicing facilities (account XX-19-27).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 9 2013-10-01 2013-10-01 false Locomotive servicing facilities (account XX-19-27... Structures § 1242.25 Locomotive servicing facilities (account XX-19-27). Separate common expenses according to distribution of common expenses in the following accounts: Locomotive Fuel (XX-51-67 and...

  15. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 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...

  16. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 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)...

  17. 49 CFR 230.12 - Movement of non-complying steam locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 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)...

  18. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 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...

  19. 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...

  20. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  1. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  2. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  3. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  4. 40 CFR 1033.750 - Changing a locomotive's FEL at remanufacture.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Changing a locomotive's FEL at... Certification § 1033.750 Changing a locomotive's FEL at remanufacture. Locomotives are generally required to be certified to the previously applicable emission standard or FEL when remanufactured. This section...

  5. 49 CFR 216.13 - Special notice for repairs-locomotive.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Special notice for repairs-locomotive. 216.13..., LOCOMOTIVE AND EQUIPMENT Special Notice for Repairs § 216.13 Special notice for repairs—locomotive. (a) When..., specifying the repairs completed. The carrier officer or employee directly responsible for the repairs...

  6. 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...

  7. 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)...

  8. 49 CFR 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 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...

  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 231.17 - Specifications common to all steam locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 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...

  11. 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)...

  12. 40 CFR 1033.625 - Special certification provisions for non-locomotive-specific engines.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... throughout the locomotive's useful life. (iii) The emission data submitted under 40 CFR part 1039 (or part 89... freshly manufactured or remanufactured locomotives using non-locomotive-specific engines (as defined in... engines included in engine families certified under 40 CFR part 1039 (or part 89) in limited...

  13. 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.

  14. 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

  15. 40 CFR 1033.335 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... least five percent of your annual production per model year per installer or ten per engine family per... during the model year, you determine that the three locomotives audited are found to have had any... the following information: (1) The location and description of your audit facilities which...

  16. 40 CFR 1033.230 - Grouping locomotives into engine families.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... temperature within desired limits (thermostat, on-off radiator fan(s), radiator shutters, etc.). (3) The... temperature within desired limits (thermostat, on-off radiator fan(s), radiator shutters, etc.). (3) The... calculated emission rates differ, such as locomotives with and without energy-saving design features. For...

  17. 40 CFR 1033.230 - Grouping locomotives into engine families.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... temperature within desired limits (thermostat, on-off radiator fan(s), radiator shutters, etc.). (3) The... temperature within desired limits (thermostat, on-off radiator fan(s), radiator shutters, etc.). (3) The... calculated emission rates differ, such as locomotives with and without energy-saving design features. For...

  18. 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

  19. 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.

  20. 49 CFR 210.27 - New locomotive certification.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false New locomotive certification. 210.27 Section 210.27 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION COMPLIANCE REGULATIONS Inspection...

  1. 49 CFR 210.27 - New locomotive certification.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false New locomotive certification. 210.27 Section 210.27 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION COMPLIANCE REGULATIONS Inspection...

  2. 49 CFR 210.27 - New locomotive certification.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false New locomotive certification. 210.27 Section 210.27 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION COMPLIANCE REGULATIONS Inspection...

  3. 49 CFR 210.27 - New locomotive certification.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false New locomotive certification. 210.27 Section 210.27 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION COMPLIANCE REGULATIONS Inspection...

  4. 49 CFR 210.27 - New locomotive certification.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false New locomotive certification. 210.27 Section 210.27 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF TRANSPORTATION RAILROAD NOISE EMISSION COMPLIANCE REGULATIONS Inspection...

  5. 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

  6. 49 CFR 229.121 - Locomotive cab noise.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Locomotive cab noise. 229.121 Section 229.121... include, but are not limited to: defective cab window seals; defective cab door seals; broken or inoperative windows; deteriorated insulation or insulation that has been removed for other reasons; broken...

  7. 40 CFR 1033.230 - Grouping locomotives into engine families.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... temperature within desired limits (thermostat, on-off radiator fan(s), radiator shutters, etc.). (3) The... temperature within desired limits (thermostat, on-off radiator fan(s), radiator shutters, etc.). (3) The... calculated emission rates differ, such as locomotives with and without energy-saving design features. For...

  8. 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.

  9. 29 CFR 1910.180 - Crawler locomotive and truck cranes.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., mounted on a base or car equipped for travel on railroad track. It may be self-propelled or propelled by... on a locomotive crane car, which can be connected to the track. (33) Reeving means a rope system in... pound-feet net stabilizing moment about the rail, which shall be minimum with such booms. (ii)...

  10. 29 CFR 1910.180 - Crawler locomotive and truck cranes.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., mounted on a base or car equipped for travel on railroad track. It may be self-propelled or propelled by... on a locomotive crane car, which can be connected to the track. (33) Reeving means a rope system in... pound-feet net stabilizing moment about the rail, which shall be minimum with such booms. (ii)...

  11. 29 CFR 1910.180 - Crawler locomotive and truck cranes.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., mounted on a base or car equipped for travel on railroad track. It may be self-propelled or propelled by... on a locomotive crane car, which can be connected to the track. (33) Reeving means a rope system in... pound-feet net stabilizing moment about the rail, which shall be minimum with such booms. (ii)...

  12. 29 CFR 1910.180 - Crawler locomotive and truck cranes.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., mounted on a base or car equipped for travel on railroad track. It may be self-propelled or propelled by... on a locomotive crane car, which can be connected to the track. (33) Reeving means a rope system in... pound-feet net stabilizing moment about the rail, which shall be minimum with such booms. (ii)...

  13. 29 CFR 1910.180 - Crawler locomotive and truck cranes.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., mounted on a base or car equipped for travel on railroad track. It may be self-propelled or propelled by... on a locomotive crane car, which can be connected to the track. (33) Reeving means a rope system in... pound-feet net stabilizing moment about the rail, which shall be minimum with such booms. (ii)...

  14. 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

  15. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... accommodate the turning arc of a six-wheel truck and its appurtenances, the inside edge of the switching step... contrasting color. On locomotives built after March 31, 1977, switching steps shall be illuminated; on...) inches; (iv) Be painted in a contrasting color to a height of at least forty-eight (48) inches above...

  16. Effects of roughness and compressibility of flooring on cow locomotion.

    PubMed

    Rushen, J; de Passillé, A M

    2006-08-01

    We examined the effects of roughness and degree of compressibility of flooring on the locomotion of dairy cows. We observed 16 cows walking down specially constructed walkways with materials that differed in surface roughness and degree of compressibility. Use of a commercially available soft rubber flooring material decreased slipping, number of strides, and time to traverse the corridor. These effects were most apparent at difficult sections of the corridor, such as at the start, at a right-angle turn, and across a gutter. Covering the walkway with a thin layer of slurry increased frequency of slipping, number of strides, and time taken to traverse the walkway. Effects of adding slurry were not overcome by increasing surface roughness or compressibility. Placing more compressible materials under a slip-resistant material reduced the time and number of steps needed to traverse the corridor but did not reduce slips, and the effects on cow locomotion varied nonlinearly with the degree of compressibility of the floor. Use of commercially available rubber floors improved cow locomotion compared with concrete floors. However, standard engineering measures of the floor properties may not predict effects of the floor on cow behavior well. Increasing compressibility of the flooring on which cows walk, independently of the roughness of the surface, can improve cow locomotion.

  17. 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.

  18. 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…

  19. Locomotive Crane placing concrete on trestle at coal dock (Pier ...

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

    Locomotive Crane placing concrete on trestle at coal dock (Pier 01) - looking southeast. Taken Jan 4, 1924. 14th Naval District Photo Collection Item No. 4872-B - U.S. Naval Base, Pearl Harbor, Exterior Cranes, Waterfront Crane Track System, Pearl City, Honolulu County, HI

  20. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... step that is not less than seven (7) inches deep by eighteen (18) inches wide on locomotives built prior to April 1, 1977, and of not less than seven (7) inches deep by twenty-four (24) inches wide on... the tread surface as open space must be used. (ii) When the step material creates a second...

  1. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... step that is not less than seven (7) inches deep by eighteen (18) inches wide on locomotives built prior to April 1, 1977, and of not less than seven (7) inches deep by twenty-four (24) inches wide on... the tread surface as open space must be used. (ii) When the step material creates a second...

  2. 6. VIEW OF BORING MILL. Chuck action of locomotive wheel ...

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

    6. VIEW OF BORING MILL. Chuck action of locomotive wheel Wheel weight 1200 pounds, 3'-0' diameter. Table 53' in diameter Wheel is 48'. Largest hole that can be bored is 9-1/2' plus (GE axle is 10'). - Juniata Shops, Erecting Shop & Machine Shop, East of Fourth Avenue, between Fourth & Fifth Streets, Altoona, Blair County, PA

  3. 4. 'OLD NUMBER SIX' STEAM LOCOMOTIVE USED BY SEATTLE ...

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

    4. 'OLD NUMBER SIX' -- STEAM LOCOMOTIVE USED BY SEATTLE CITY LIGHT ON THEIR RAILROAD FROM MARBLEMOUNT TO DIABLE AND NOW A POPULAR TOURIST ATTRACTION IN NEWHALEM, 1989. - Skagit Power Development, Skagit River & Newhalem Creek Hydroelectric Project, On Skagit River, Newhalem, Whatcom County, WA

  4. 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…

  5. 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…

  6. 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

  7. 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.

  8. 49 CFR 231.30 - Locomotives used in switching service.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... means that portion of anti-skid surface of a switching step that actually is contacted by a shoe or boot... locomotives built after March 31, 1977. (5) Material. (i) Steel or other material of equivalent or better strength and deflection characteristics, anti-skid, safety design, having at least fifty percent (50%)...

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

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... means that portion of anti-skid surface of a switching step that actually is contacted by a shoe or boot... locomotives built after March 31, 1977. (5) Material. (i) Steel or other material of equivalent or better strength and deflection characteristics, anti-skid, safety design, having at least fifty percent (50%)...

  10. 40 CFR 92.511 - Remanufactured locomotives: installation audit requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... in complete conformance with all applicable regulations under 40 CFR part 92. No emission-related...: installation audit requirements. 92.511 Section 92.511 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) CONTROL OF AIR POLLUTION FROM LOCOMOTIVES AND...

  11. 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.

  12. 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

  13. Bird terrestrial locomotion as revealed by 3D kinematics.

    PubMed

    Abourachid, Anick; Hackert, Remi; Herbin, Marc; Libourel, Paul A; Lambert, François; Gioanni, Henri; Provini, Pauline; Blazevic, Pierre; Hugel, Vincent

    2011-12-01

    Most birds use at least two modes of locomotion: flying and walking (terrestrial locomotion). Whereas the wings and tail are used for flying, the legs are mainly used for walking. The role of other body segments remains, however, poorly understood. In this study, we examine the kinematics of the head, the trunk, and the legs during terrestrial locomotion in the quail (Coturnix coturnix). Despite the trunk representing about 70% of the total body mass, its function in locomotion has received little scientific interest to date. This prompted us to focus on its role in terrestrial locomotion. We used high-speed video fluoroscopic recordings of quails walking at voluntary speeds on a trackway. Dorso-ventral and lateral views of the motion of the skeletal elements were recorded successively and reconstructed in three dimensions using a novel method based on the temporal synchronisation of both views. An analysis of the trajectories of the body parts and their coordination showed that the trunk plays an important role during walking. Moreover, two sub-systems participate in the gait kinematics: (i) the integrated 3D motion of the trunk and thighs allows for the adjustment of the path of the centre of mass; (ii) the motion of distal limbs transforms the alternating forward motion of the feet into a continuous forward motion at the knee and thus assures propulsion. Finally, head bobbing appears qualitatively synchronised to the movements of the trunk. An important role for the thigh muscles in generating the 3D motion of the trunk is suggested by an analysis of the pelvic anatomy. PMID:21982408

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

    PubMed

    Holt, N C; Azizi, E

    2016-01-27

    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.

  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... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  16. 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... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  17. 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... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  18. 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... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  19. 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... the provisions of 40 CFR part 1065, subpart F for general pre-test procedures (including engine and... way you choose to warm it up prior to beginning the sample preconditioning specified in 40 CFR...

  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. Study of using oxygen-enriched combustion air for locomotive diesel engines

    SciTech Connect

    Poola, R.B.; Sekar, R.; Assanis, D.N.; Cataldi, G.R.

    1996-12-31

    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 output 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 can improve 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 with its attendant higher combustion temperatures, reduces emissions of particulates and visible smoke but increases NO emissions (by up to three times at 26% oxygen content). Therefore, exhaust gas after-treatment and heat recovery would be required if the full potential of oxygen enrichment for improving the performance of locomotive diesel engines is to be realized.

  2. Study of using oxygen-enriched combustion air for locomotive diesel engines

    SciTech Connect

    Poola, R.B.; Sekar, R.; Assanis, D.N.; Cataldi, G.R.

    1996-10-01

    A thermodynamic simulation is used to study effects of O2-enriched intake air on performance and NO emissions of a locomotive diesel engine. Parasitic power of the air separation membrane required to supply the O2-enriched air is also estimated. For a given constraint on peak cylinder pressure, gross and net power output of an engine operating under different levels of O2 enrichment are compared with those obtained when a high-boost turbocharged engine is used. A 4% increase in peak cylinder pressure can result in 13% increase in net engine power when intake air with 28 vol% O2 is used and fuel injection timing retarded by 4 degrees. When the engine is turbocharged to a higher inlet boost, the same increase in peak cylinder pressure can result in only 4% improvement in power. If part of the higher exhaust enthalpies from the O2 enrichment is recovered, the power requirements of the air separator membrane can be met. O2 enrichment with its higher combustion temperatures reduces emissions of particulates and visible smoke but increases NO emissions (by up to 3 times at 26% O2 content). Therefore, exhaust gas after-treatment and heat recovery would be required if the full potential of O2 enrichment for improving the performance of locomotive diesel engines is to be realized.

  3. 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

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

    PubMed

    Erickson, Jonathan C; Herrera, María; Bustamante, Mauricio; 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.

  5. 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.

  6. Spinal corollary discharge modulates motion sensing during vertebrate locomotion.

    PubMed

    Chagnaud, Boris P; Banchi, Roberto; Simmers, John; Straka, Hans

    2015-09-04

    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.

  7. Locomotive consequences of non-axisymmetric flagellar configurations

    NASA Astrophysics Data System (ADS)

    Fu, Henry; Marcos, Marcos; Hyon, Yunkyong; Powers, Thomas; Stocker, Roman

    2011-11-01

    Although peritrichous bacteria can form flagellar bundles at many attachment points and directions relative to the cell body, locomotion of these bacteria is often modeled as arising from a polar bundle oriented along the cell body axis. We discuss the consequences of non-axisymmetric flagellar configurations for bacterial locomotion and implications for bacterial behavior using a boundary element method (BEM) based on the method of regularized Stokeslets. We validate our BEM by comparing to analytic results for spheres and ellipsoids, as well as results in the literature for axisymmetric flagella with spherical and ellipsoidal heads obtained from other boundary element methods and slender body theory. Non-axisymmetric flagellar configurations generically lead to wobbling cell bodies and wiggling helical cell trajectories, both of which have been observed experimentally. We compare experimental and numerically calculated wiggling trajectories to deduce information about flagellar geometries of swimming B. subtilis. We discuss the implications of off-axis flagellar geometries for bacterial rheotaxis and chemotaxis.

  8. 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.

  9. Talking about walking: biomechanics and the language of locomotion.

    PubMed

    Malt, Barbara C; Gennari, Silvia; Imai, Mutsumi; Ameel, Eef; Tsuda, Naoaki; Majid, Asifa

    2008-03-01

    What drives humans around the world to converge in certain ways in their naming while diverging dramatically in others? We studied how naming patterns are constrained by investigating whether labeling of human locomotion reflects the biomechanical discontinuity between walking and running gaits. Similarity judgments of a student locomoting on a treadmill at different slopes and speeds revealed perception of this discontinuity. Naming judgments of the same clips by speakers of English, Japanese, Spanish, and Dutch showed lexical distinctions between walking and running consistent with the perceived discontinuity. Typicality judgments showed that major gait terms of the four languages share goodness-of-example gradients. These data demonstrate that naming reflects the biomechanical discontinuity between walking and running and that shared elements of naming can arise from correlations among stimulus properties that are dynamic and fleeting. The results support the proposal that converging naming patterns reflect structure in the world, not only acts of construction by observers. PMID:18315795

  10. 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

  11. 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 Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF...

  12. 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 Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF...

  13. 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 Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION, DEPARTMENT OF...

  14. Theoretical and experimental study on a compliant flipper-leg during terrestrial locomotion.

    PubMed

    Fang, Tao; Zhou, Youcheng; Li, Shikun; Xu, Min; Liang, Haiyi; Li, Weihua; Zhang, Shiwu

    2016-01-01

    An amphibious robot with straight compliant flipper-legs can conquer various amphibious environments. The robot can rotate its flipper-legs and utilize their large deflection to walk on rough terrain, and it can oscillate the straight flipper-legs to propel itself underwater. This paper focuses on the dynamics of the compliant straight flipper-legs during terrestrial locomotion by modeling its deformation dynamically with large deflection theory and simulating it to investigate the parameters of locomotion such as trajectory, velocity, and propulsion. To validate the theoretical model of dynamic locomotion, a single-leg experimental platform is used to explore the flipper-legs in motion with various structural and kinematic parameters. Furthermore, a robotic platform mounting with four compliant flipper-legs is also developed and used to experiment with locomotion. The trajectories of the rotating axle of the compliant flipper-leg during locomotion were approximately coincidental in simulation and in experiments. The speed of locomotion and cost of transport during locomotion were explored and analyzed. The performance of different types of compliant flipper-legs during locomotion shows that varying the degrees of stiffness will have a significant effect on their locomotion. The dynamic model and analysis of the compliant flipper-leg for terrestrial locomotion facilitates the ability of amphibious robots to conquer complex environments. PMID:27530372

  15. Sensory regulation of network components underlying ciliary locomotion in Hermissenda.

    PubMed

    Crow, Terry; Tian, Lian-Ming

    2008-11-01

    Ciliary locomotion in the nudibranch mollusk Hermissenda is modulated by the visual and graviceptive systems. Components of the neural network mediating ciliary locomotion have been identified including aggregates of polysensory interneurons that receive monosynaptic input from identified photoreceptors and efferent neurons that activate cilia. Illumination produces an inhibition of type I(i) (off-cell) spike activity, excitation of type I(e) (on-cell) spike activity, decreased spike activity in type III(i) inhibitory interneurons, and increased spike activity of ciliary efferent neurons. Here we show that pairs of type I(i) interneurons and pairs of type I(e) interneurons are electrically coupled. Neither electrical coupling or synaptic connections were observed between I(e) and I(i) interneurons. Coupling is effective in synchronizing dark-adapted spontaneous firing between pairs of I(e) and pairs of I(i) interneurons. Out-of-phase burst activity, occasionally observed in dark-adapted and light-adapted pairs of I(e) and I(i) interneurons, suggests that they receive synaptic input from a common presynaptic source or sources. Rhythmic activity is typically not a characteristic of dark-adapted, light-adapted, or light-evoked firing of type I interneurons. However, burst activity in I(e) and I(i) interneurons may be elicited by electrical stimulation of pedal nerves or generated at the offset of light. Our results indicate that type I interneurons can support the generation of both rhythmic activity and changes in tonic firing depending on sensory input. This suggests that the neural network supporting ciliary locomotion may be multifunctional. However, consistent with the nonmuscular and nonrhythmic characteristics of visually modulated ciliary locomotion, type I interneurons exhibit changes in tonic activity evoked by illumination. PMID:18768639

  16. Performance analysis of jump-gliding locomotion for miniature robotics.

    PubMed

    Vidyasagar, A; Zufferey, Jean-Christohphe; Floreano, Dario; Kovač, M

    2015-04-01

    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. PMID:25811417

  17. 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

  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. 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

  20. 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.

  1. Brief anesthesia, but not voluntary locomotion, significantly alters cortical temperature

    PubMed Central

    Shirey, Michael J.; Kudlik, D'Anne E.; Huo, Bing-Xing; Greene, Stephanie E.; Drew, Patrick J.

    2015-01-01

    Changes in brain temperature can alter electrical properties of neurons and cause changes in behavior. However, it is not well understood how behaviors, like locomotion, or experimental manipulations, like anesthesia, alter brain temperature. We implanted thermocouples in sensorimotor cortex of mice to understand how cortical temperature was affected by locomotion, as well as by brief and prolonged anesthesia. Voluntary locomotion induced small (∼0.1°C) but reliable increases in cortical temperature that could be described using a linear convolution model. In contrast, brief (90-s) exposure to isoflurane anesthesia depressed cortical temperature by ∼2°C, which lasted for up to 30 min after the cessation of anesthesia. Cortical temperature decreases were not accompanied by a concomitant decrease in the γ-band local field potential power, multiunit firing rate, or locomotion behavior, which all returned to baseline within a few minutes after the cessation of anesthesia. In anesthetized animals where core body temperature was kept constant, cortical temperature was still >1°C lower than in the awake animal. Thermocouples implanted in the subcortex showed similar temperature changes under anesthesia, suggesting these responses occur throughout the brain. Two-photon microscopy of individual blood vessel dynamics following brief isoflurane exposure revealed a large increase in vessel diameter that ceased before the brain temperature significantly decreased, indicating cerebral heat loss was not due to increased cerebral blood vessel dilation. These data should be considered in experimental designs recording in anesthetized preparations, computational models relating temperature and neural activity, and awake-behaving methods that require brief anesthesia before experimental procedures. PMID:25972579

  2. On the feasibility of life-saving locomotive bumpers.

    PubMed

    Paden, Brad E; Kelly, Paraic M; Hines, Jacob A; Bothman, David; Simms, Ciaran

    2016-04-01

    Motivated by the thousands of pedestrians killed each year in train impacts, this paper investigates the life-saving capability of four high-level locomotive bumper concepts. The head motions produced by the four concepts are modeled as one or two square acceleration pulses and are analyzed using the Head Injury Criterion (HIC). Surprisingly, the analyses show that all four concepts can achieve HIC values of less than 200 for an impact with a locomotive traveling at 100 km/h. Two of the concepts eject the pedestrian trackside with at a velocity of roughly 40 km/h and the risk of ground-impact injury is discussed in the context of related automobile accident data. The computed bumper lengths are a fraction of the overall length of a locomotive and are thus feasible for practical implementation. One concept involves an oblique impact and the potential for rotational head injury is analyzed. This basic feasibility research motivates future investigations into the detailed design of bumper shapes, multi-body pedestrian simulations, and finite-element injury models. PMID:26866281

  3. Enhanced Caenorhabditis elegans Locomotion in a Structured Microfluidic Environment

    PubMed Central

    Park, Sungsu; Hwang, Hyejin; Nam, Seong-Won; Martinez, Fernando; Austin, Robert H.; Ryu, William S.

    2008-01-01

    Background Behavioral studies of Caenorhabditis elegans traditionally are done on the smooth surface of agar plates, but the natural habitat of C. elegans and other nematodes is the soil, a complex and structured environment. In order to investigate how worms move in such environments, we have developed a technique to study C. elegans locomotion in microstructures fabricated from agar. Methodology/Principal Findings When placed in open, liquid-filled, microfluidic chambers containing a square array of posts, we discovered that worms are capable of a novel mode of locomotion, which combines the fast gait of swimming with the more efficient movements of crawling. When the wavelength of the worms matched the periodicity of the post array, the microstructure directed the swimming and increased the speed of C. elegans ten-fold. We found that mutants defective in mechanosensation (mec-4, mec-10) or mutants with abnormal waveforms (unc-29) did not perform this enhanced locomotion and moved much more slowly than wild-type worms in the microstructure. Conclusion/Significance These results show that the microstructure can be used as a behavioral screen for mechanosensory and uncoordinated mutants. It is likely that worms use mechanosensation in the movement and navigation through heterogeneous environments. PMID:18575618

  4. A strategy for identifying locomotion modes using surface electromyography.

    PubMed

    Huang, He; Kuiken, Todd A; Lipschutz, Robert D

    2009-01-01

    This study investigated the use of surface electromyography (EMG) combined with pattern recognition (PR) to identify user locomotion modes. Due to the nonstationary characteristics of leg EMG signals during locomotion, a new phase-dependent EMG PR strategy was proposed for classifying the user's locomotion modes. The variables of the system were studied for accurate classification and timely system response. The developed PR system was tested on EMG data collected from eight able-bodied subjects and two subjects with long transfemoral (TF) amputations while they were walking on different terrains or paths. The results showed reliable classification for the seven tested modes. For eight able-bodied subjects, the average classification errors in the four defined phases using ten electrodes located over the muscles above the knee (simulating EMG from the residual limb of a TF amputee) were 12.4% +/- 5.0%, 6.0% +/- 4.7%, 7.5% +/- 5.1%, and 5.2% +/- 3.7%, respectively. Comparable results were also observed in our pilot study on the subjects with TF amputations. The outcome of this investigation could promote the future design of neural-controlled artificial legs.

  5. Visual analysis and image motion in locomoting cats.

    PubMed

    Sherk, H; Fowler, G A

    2001-03-01

    During locomotion, observers see a characteristic pattern of motion referred to as an optic flow field. To investigate how they make use of this pattern, we have developed a paradigm for testing visual function during locomotion. Foot placement was recorded while cats walked down an alley cluttered with a high density of small objects; the task was to avoid stepping on any object. In the experiments reported here, motion cues were eliminated by the use of low-frequency strobe lighting. In bright continuous light cats performed with great accuracy, and likewise at scotopic light levels. However, in strobe lighting their error rates increased more than threefold. This deterioration could not be attributed to lower acuity, since the cats' performance remained excellent when the light level was reduced well below that afforded by the strobe light. When very dim continuous light was combined with low-frequency strobe lighting, performance was substantially better than under strobe light alone. We conclude that motion-sensitive neurons make a major contribution to visual guidance of foot placement during locomotion. When strobe lighting is combined with very dim continuous light, even the minimal motion information available in the intervals between bright strobe flashes improves performance significantly. Cats were also trained to discriminate between complex patterns, and this discrimination was not affected by strobe lighting, suggesting that motion-sensitive neurons are not critical for this analysis. PMID:11285021

  6. 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.

  7. 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.

  8. Central pattern generator for locomotion: anatomical, physiological, and pathophysiological considerations.

    PubMed

    Guertin, Pierre A

    2012-01-01

    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.

  9. 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.

  10. Kinematics of treadmill locomotion in mice raised in hypergravity.

    PubMed

    Bojados, Mickael; Herbin, Marc; Jamon, Marc

    2013-05-01

    The study compared the motor performance of adult C57Bl/6J mice previously exposed to a 2G gravity environment during different periods of their development. 12 mice were housed in a large diameter centrifuge from the conception to Postnatal day 10 (P10). Another group of 10 mice was centrifuged form P10 to P30, and a third group of 9 mice was centrifuged from conception to P30. Their gait parameters, and kinematics of joint excursions were compared with 11 control mice, at the age of 2 months using a video-radiographic apparatus connected to a motorized treadmill. The mice that returned to Earth gravity level at the age of P10 showed a motor pattern similar to control mice. At variance the two groups that were centrifuged from P10 to P30 showed a different motor pattern with smaller and faster strides to walk at the same velocity as controls. On the other hand all the centrifuged mice showed significant postural changes, particularly with a more extended ankle joint, but the mice centrifuged during the whole experimental period differed even more. Our results showed that the exposure to hypergravity before P10 sufficed to modify the posture, suggesting that postural control starts before the onset of locomotion, whereas the gravity constraint perceived between P10 and P30 conditioned the tuning of quadruped locomotion with long term consequences. These results support the existence of a critical period in the acquisition of locomotion in mice. PMID:23352767

  11. 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

  12. 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.

  13. Cellular and molecular mechanics of gliding locomotion in eukaryotes.

    PubMed

    Heintzelman, Matthew B

    2006-01-01

    Gliding is a form of substrate-dependent cell locomotion exploited by a variety of disparate cell types. Cells may glide at rates well in excess of 1 microm/sec and do so without the gross distortion of cellular form typical of amoeboid crawling. In the absence of a discrete locomotory organelle, gliding depends upon an assemblage of molecules that links cytoplasmic motor proteins to the cell membrane and thence to the appropriate substrate. Gliding has been most thoroughly studied in the apicomplexan parasites, including Plasmodium and Toxoplasma, which employ a unique assortment of proteins dubbed the glideosome, at the heart of which is a class XIV myosin motor. Actin and myosin also drive the gliding locomotion of raphid diatoms (Bacillariophyceae) as well as the intriguing form of gliding displayed by the spindle-shaped cells of the primitive colonial protist Labyrinthula. Chlamydomonas and other flagellated protists are also able to abandon their more familiar swimming locomotion for gliding, during which time they recruit a motility apparatus independent of that driving flagellar beating.

  14. 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.

  15. The influence of drag on human locomotion in water.

    PubMed

    Pendergast, D; Mollendorf, J; Zamparo, P; Termin, A; Bushnell, D; Paschke, D

    2005-01-01

    Propulsion in water requires a propulsive force to overcome drag. Male subjects were measured for cycle frequency, energy cost and drag (D) as a function of velocity (V), up to maximal V, for fin and front crawl swimming, kayaking and rowing. The locomotion with the largest propulsive arms and longest hulls traveled the greatest distance per cycle (d/c) and reached higher maximal V. D while locomotoring increased as a function of V, with lower levels for kayaking and rowing at lower Vs. For Vs below 1 m/s, pressure D dominated, while friction D dominated up to 3 m/s, after which wave D dominated total D. Sport training reduced the D, increased d/c, and thus lowered C and increased maximal V. Maximal powers and responses to training were similar in all types of locomotion. To minimize C or maximize V, D has to be minimized by tailoring D type (friction, pressure or wave) to the form of locomotion and velocity.

  16. Unsteady locomotion: integrating muscle function with whole body dynamics and neuromuscular control.

    PubMed

    Biewener, Andrew A; Daley, Monica A

    2007-09-01

    By integrating studies of muscle function with analysis of whole body and limb dynamics, broader appreciation of neuromuscular function can be achieved. Ultimately, such studies need to address non-steady locomotor behaviors relevant to animals in their natural environments. When animals move slowly they likely rely on voluntary coordination of movement involving higher brain centers. However, when moving fast, their movements depend more strongly on responses controlled at more local levels. Our focus here is on control of fast-running locomotion. A key observation emerging from studies of steady level locomotion is that simple spring-mass dynamics, which help to economize energy expenditure, also apply to stabilization of unsteady running. Spring-mass dynamics apply to conditions that involve lateral impulsive perturbations, sudden changes in terrain height, and sudden changes in substrate stiffness or damping. Experimental investigation of unsteady locomotion is challenging, however, due to the variability inherent in such behaviors. Another emerging principle is that initial conditions associated with postural changes following a perturbation define different context-dependent stabilization responses. Distinct stabilization modes following a perturbation likely result from proximo-distal differences in limb muscle architecture, function and control strategy. Proximal muscles may be less sensitive to sudden perturbations and appear to operate, in such circumstances, under feed-forward control. In contrast, multiarticular distal muscles operate, via their tendons, to distribute energy among limb joints in a manner that also depends on the initial conditions of limb contact with the ground. Intrinsic properties of these distal muscle-tendon elements, in combination with limb and body dynamics, appear to provide rapid initial stabilizing mechanisms that are often consistent with spring-mass dynamics. These intrinsic mechanisms likely help to simplify the neural

  17. Unsteady locomotion: integrating muscle function with whole body dynamics and neuromuscular control

    PubMed Central

    Biewener, Andrew A.; Daley, Monica A.

    2009-01-01

    Summary By integrating studies of muscle function with analysis of whole body and limb dynamics, broader appreciation of neuromuscular function can be achieved. Ultimately, such studies need to address non-steady locomotor behaviors relevant to animals in their natural environments. When animals move slowly they likely rely on voluntary coordination of movement involving higher brain centers. However, when moving fast, their movements depend more strongly on responses controlled at more local levels. Our focus here is on control of fast-running locomotion. A key observation emerging from studies of steady level locomotion is that simple spring-mass dynamics, which help to economize energy expenditure, also apply to stabilization of unsteady running. Spring-mass dynamics apply to conditions that involve lateral impulsive perturbations, sudden changes in terrain height, and sudden changes in substrate stiffness or damping. Experimental investigation of unsteady locomotion is challenging, however, due to the variability inherent in such behaviors. Another emerging principle is that initial conditions associated with postural changes following a perturbation define different context-dependent stabilization responses. Distinct stabilization modes following a perturbation likely result from proximo-distal differences in limb muscle architecture, function and control strategy. Proximal muscles may be less sensitive to sudden perturbations and appear to operate, in such circumstances, under feed-forward control. In contrast, multiarticular distal muscles operate, via their tendons, to distribute energy among limb joints in a manner that also depends on the initial conditions of limb contact with the ground. Intrinsic properties of these distal muscle–tendon elements, in combination with limb and body dynamics, appear to provide rapid initial stabilizing mechanisms that are often consistent with spring-mass dynamics. These intrinsic mechanisms likely help to simplify the

  18. 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

  19. 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

  20. 40 CFR 1033.650 - Incidental use exemption for Canadian and Mexican locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Special Compliance... the United States and that enter the United States temporarily from Canada or Mexico. We will...

  1. 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.

  2. Sexuality of Disabled Athletes Depending on the Form of Locomotion.

    PubMed

    Plinta, Ryszard; Sobiecka, Joanna; Drosdzol-Cop, Agnieszka; Nowak-Brzezińska, Agnieszka; Skrzypulec-Plinta, Violetta

    2015-11-22

    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

  3. 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.

  4. Climbing, falling, and jamming during ant locomotion in confined environments

    PubMed Central

    Gravish, Nick; Monaenkova, Daria; Goodisman, Michael A. D.; Goldman, Daniel I.

    2013-01-01

    Locomotion emerges from effective interactions of an individual with its environment. Principles of biological terrestrial locomotion have been discovered on unconfined vertical and horizontal substrates. However, a diversity of organisms construct, inhabit, and move within confined spaces. Such animals are faced with locomotor challenges including limited limb range of motion, crowding, and visual sensory deprivation. Little is known about how these organisms accomplish their locomotor tasks, and such environments challenge human-made devices. To gain insight into how animals move within confined spaces, we study the locomotion of the fire ant Solenopsis invicta, which constructs subterranean tunnel networks (nests). Laboratory experiments reveal that ants construct tunnels with diameter, D, comparable to body length, L = 3.5 ± 0.5 mm. Ants can move rapidly (> 9 bodylengths per s) within these environments; their tunnels allow for effective limb, body, and antennae interaction with walls, which facilitate rapid slip-recovery during ascending and descending climbs. To examine the limits of slip-recovery in artificial tunnels, we perform perturbations consisting of rapid downward accelerations of the tunnels, which induce falls. Below a critical tunnel diameter, Ds = 1.31 ± 0.02 L, falls are always arrested through rapid interaction of appendages and antennae with tunnel walls to jam the falls. Ds is comparable to the size of incipient nest tunnels (D = 1.06 ± 0.23 L), supporting our hypothesis that fire ants construct environments that simplify their control task when moving through the nest, likely without need for rapid nervous system intervention. PMID:23690589

  5. Extensor motoneurone properties are altered immediately before and during fictive locomotion in the adult decerebrate rat

    PubMed Central

    MacDonell, C W; Power, K E; Chopek, J W; Gardiner, K R; Gardiner, P F

    2015-01-01

    Key points This is the first report, in adult decerebrate rats, to examine intracellular hindlimb motoneurone properties during quiescence, fictive locomotion and a tonic period immediately before fictive locomotion that is characterized by increased peripheral nerve activity. It is shown for the first time during fictive locomotion that motoneurones become more responsive in the tonic period, suggesting that the motoneurone pool becomes primed before patterned motor output commences. Spike frequency adaptation exists in quiescence and during fictive locomotion during constant excitation with injected current but not during centrally driven fictive locomotion. Motoneurones within the extensor motor pool show changes in excitability even when they are not directly involved in locomotion. The data show increased responsiveness of motoneurones during locomotion via a lowered threshold for spike initiation and decreased rheobase. Abstract This study examined motoneurone properties during fictive locomotion in the adult rat for the first time. Fictive locomotion was induced via electrical stimulation of the mesencephalic locomotor region in decerebrate adult rats under neuromuscular blockade to compare basic and rhythmic motoneurone properties in antidromically identified extensor motoneurones during: (1) quiescence, before and after fictive locomotion; (2) the ‘tonic’ period immediately preceding locomotor-like activity, whereby the amplitude of peripheral flexor (peroneal) and extensor (tibial) nerves are increased but alternation has not yet occurred; and (3) locomotor-like episodes. Locomotion was identified by alternating flexor–extensor nerve activity, where the motoneurone either produced membrane oscillations consistent with a locomotor drive potential (LDP) or did not display membrane oscillation during alternating nerve activity. Cells producing LDPs were referred to as such, while those that did not were referred to as ‘idle’ motoneurones. LDP and

  6. 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

  7. 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

  8. 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.

  9. 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

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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

  15. Incorporating compliant elastomers for jumping locomotion in microrobots

    NASA Astrophysics Data System (ADS)

    Gerratt, Aaron P.; Bergbreiter, Sarah

    2013-01-01

    Small insects and other animals use a multitude of materials to realize specific functions, including locomotion. This paper demonstrates application of the first microfabrication process to incorporate high aspect ratio compliant elastomer structures in-plane with traditional silicon microelectromechanical systems (MEMS). By incorporating these new materials, compact energy storage systems based on elastomer springs for small jumping robots have been demonstrated. Results include a 4 mm×4 mm jumping mechanism that has reached heights of 32 cm, × 80 its own height, and an on-chip actuated mechanism that has been used to propel a 1.4 mg projectile over 7 cm.

  16. 40 CFR 1033.815 - Maintenance, operation, and repair.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... a violation of 40 CFR 1068.101(b). ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Maintenance, operation, and repair... Maintenance, operation, and repair. All persons who own, operate, or maintain locomotives are subject to...

  17. 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.

  18. Distinctive patterns of static and dynamic gamma motor activity during locomotion in the decerebrate cat.

    PubMed

    Taylor, A; Ellaway, P H; Durbaba, R; Rawlinson, S

    2000-12-15

    Simultaneous recordings were made from gamma (gamma) motor axons and from muscle spindle afferents of the medial gastrocnemius (MG) muscle during locomotion in decerebrate cats. The gamma-neurons were identified as static or dynamic (gammas or gammad) by correlating their behaviour during midbrain stimulation with changes in muscle spindle afferent responses to muscle stretch. On the basis of their behaviour during locomotion, gammas neurons could be divided into two groups. One group (type-1) showed strongly and smoothly modulated discharge increasing in parallel with the active muscle shortening in ankle extension, but with phase advance. The other group (type-2) also showed a modulated pattern, but with increased firing centred on the flexion phase. The proportions of the two were 13 type-1 and 7 type-2. The type-1 firing pattern accurately predicted the difference in firing frequency for secondary afferents obtained by subtracting from the recordings made during active movements the response of the same units to the movements repeated passively in the absence of fusimotor activity. The type-2 pattern also became consistent with the difference signal, when operated on by a phase lag appropriate to the effects of bag2 intrafusal fibres. These results suggest that there may be some degree of separate control of chain and bag2 intrafusal fibres. The discharge of gammad axons was also found to fluctuate with the locomotor cycle, with a pattern very distinct from that of the gammas records. The gammad firing frequency rose very suddenly from zero to a maximum at the onset of muscle shortening and continued into the beginning of lengthening. The term 'interrupted' discharge is suggested as a useful description. The timing of this discharge was shown to be appropriate for sensitising the primary afferents to detect the onset of stretch.

  19. 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...

  20. 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...

  1. 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...

  2. 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...

  3. 40 CFR 1033.615 - Voluntarily subjecting locomotives to the standards of this part.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... standards and requirements of this part for the remainder of its service life. (a) Equipment excluded from.... If we approve your request, it will be deemed to be a locomotive for the remainder of its service life. (2) In unusual circumstances, we may deem other equipment to be locomotives (at the request...

  4. 40 CFR 1033.615 - Voluntarily subjecting locomotives to the standards of this part.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Voluntarily subjecting locomotives to the standards of this part. 1033.615 Section 1033.615 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM LOCOMOTIVES Special...

  5. 40 CFR 1033.640 - Provisions for repowered and refurbished locomotives.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... COMPLY WITH THE TIER EACH TIME THAT IT IS REMANUFACTURED, EXCEPT AS ALLOWED BY 40 CFR 1033.750...) Prior to January 1, 2015, remanufactured Tier 0 switch locomotives that are deemed to be refurbished are... standards. (ii) Beginning January 1, 2015, remanufactured Tier 3 and earlier switch locomotives that...

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

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... COMPLY WITH THE TIER EACH TIME THAT IT IS REMANUFACTURED, EXCEPT AS ALLOWED BY 40 CFR 1033.750...) Prior to January 1, 2015, remanufactured Tier 0 switch locomotives that are deemed to be refurbished are... standards. (ii) Beginning January 1, 2015, remanufactured Tier 3 and earlier switch locomotives that...

  7. 49 CFR Appendix E to Part 229 - Performance Criteria for Locomotive Crashworthiness

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Performance Criteria for Locomotive Crashworthiness E Appendix E to Part 229 Transportation Other Regulations Relating to Transportation (Continued..., App. E Appendix E to Part 229—Performance Criteria for Locomotive Crashworthiness This...

  8. 49 CFR Appendix E to Part 229 - Performance Criteria for Locomotive Crashworthiness

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Performance Criteria for Locomotive Crashworthiness E Appendix E to Part 229 Transportation Other Regulations Relating to Transportation (Continued..., App. E Appendix E to Part 229—Performance Criteria for Locomotive Crashworthiness This...

  9. 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

  10. 49 CFR Appendix D to Part 238 - Requirements for External Fuel Tanks on Tier I Locomotives

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... properties of the locomotive fuel tank to reduce the risk of fuel spillage to acceptable levels under... 49 Transportation 4 2010-10-01 2010-10-01 false Requirements for External Fuel Tanks on Tier I..., App. D Appendix D to Part 238—Requirements for External Fuel Tanks on Tier I Locomotives...

  11. 49 CFR Appendix D to Part 238 - Requirements for External Fuel Tanks on Tier I Locomotives

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... properties of the locomotive fuel tank to reduce the risk of fuel spillage to acceptable levels under... 49 Transportation 4 2011-10-01 2011-10-01 false Requirements for External Fuel Tanks on Tier I..., App. D Appendix D to Part 238—Requirements for External Fuel Tanks on Tier I Locomotives...

  12. 40 CFR 92.606 - Maintenance, procurement and testing of in-use locomotives.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Maintenance, procurement and testing of in-use locomotives. 92.606 Section 92.606 Protection of Environment ENVIRONMENTAL PROTECTION... test locomotive must have a maintenance history that is representative of actual in-use conditions,...

  13. 49 CFR Appendix E to Part 229 - Performance Criteria for Locomotive Crashworthiness

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Performance Criteria for Locomotive Crashworthiness E Appendix E to Part 229 Transportation Other Regulations Relating to Transportation (Continued..., App. E Appendix E to Part 229—Performance Criteria for Locomotive Crashworthiness This...

  14. 49 CFR 1242.22 - Shop buildings-locomotives (account XX-19-24).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 9 2014-10-01 2014-10-01 false Shop buildings-locomotives (account XX-19-24... Structures § 1242.22 Shop buildings—locomotives (account XX-19-24). Separate common expenses according to distribution of common expenses in the following accounts: Machinery Repair (XX-26-40) Locomotive—Repair...

  15. 49 CFR 1242.22 - Shop buildings-locomotives (account XX-19-24).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 9 2013-10-01 2013-10-01 false Shop buildings-locomotives (account XX-19-24... Structures § 1242.22 Shop buildings—locomotives (account XX-19-24). Separate common expenses according to distribution of common expenses in the following accounts: Machinery Repair (XX-26-40) Locomotive—Repair...

  16. 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... Structures § 1242.22 Shop buildings—locomotives (account XX-19-24). Separate common expenses according to distribution of common expenses in the following accounts: Machinery Repair (XX-26-40) Locomotive—Repair...

  17. 49 CFR 1242.22 - Shop buildings-locomotives (account XX-19-24).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 9 2012-10-01 2012-10-01 false Shop buildings-locomotives (account XX-19-24... Structures § 1242.22 Shop buildings—locomotives (account XX-19-24). Separate common expenses according to distribution of common expenses in the following accounts: Machinery Repair (XX-26-40) Locomotive—Repair...

  18. 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... Structures § 1242.22 Shop buildings—locomotives (account XX-19-24). Separate common expenses according to distribution of common expenses in the following accounts: Machinery Repair (XX-26-40) Locomotive—Repair...

  19. The Role of Visual and Nonvisual Information in the Control of Locomotion

    ERIC Educational Resources Information Center

    Wilkie, Richard M.; Wann, John P.

    2005-01-01

    During locomotion, retinal flow, gaze angle, and vestibular information can contribute to one's perception of self-motion. Their respective roles were investigated during active steering: Retinal flow and gaze angle were biased by altering the visual information during computer-simulated locomotion, and vestibular information was controlled…

  20. 49 CFR 236.512 - Cab signal indication when locomotive enters block where restrictive conditions obtain.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Cab signal indication when locomotive enters block... TRAIN CONTROL SYSTEMS, DEVICES, AND APPLIANCES Automatic Train Stop, Train Control and Cab Signal Systems Standards § 236.512 Cab signal indication when locomotive enters block where...