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Geography and the properties of surfaces. The law of travel and its application to rail traffic
106
ABSTRACTS of two counterrotating rotors which give forward and backward thrust to the vehicle. When both rotors are made to turn in the same direction, the vehicle will move laterally; however, there is no provision for steering when the vehicle is moving laterally. Trafficability tests with the marsh screw were performed to determine its performance on three soil types: sand, clay, and silt. Repetitivepass tests and speed tests were conducted on clay and sand; towing tests on clay, silt, and sand; slope-climbing tests on sand; and obstacle tests on silt, for comparison. Tests with an M29C weasel were conducted and performance curves from previous test programs were utilized. (U.S. Gov. Res. Dev. Dep., 10.8.69, AD-450621.)
49.
J . K . Kouwenhoven. Spring cultivations and wheeltracks. J. agric. Engng Res. 15 (1), 17-26 (1970). During spring cultivations the final part of the increase in pore space resulting from ploughing is often lost by the amount of driving over the soil. In order to prevent heavy compaction of the loose soil and accompanying deep wheeltracks the wheels are often enlarged by the use of cagewheels. This brings on more shallow but much wider tracks, resulting in an increased loss of loose soil. This should be prevented if a large quantity of loose soil is needed (e.g. potatoes) by using rather narrow tyres and dozing the loose soil aside in front of the wheels. For shallow even seedbeds (e.g. sugar-beet) however tyres and cagewheels or preferably wide cagewheels without tyres should be used. (Author's summary.)
50.
K. Kubota and T. Sato. A study on the stress-dilatancy relation of a sand sample. Proc. Sixteenth Japan National Congress for Applied Mechanics, Tokyo, Oct. 19-20, 1966, 173-179 (Dec. 1967). A theoretical and experimental study of the nature of deformation of a sand sample when tested in the triaxial apparatus is presented, and a new stress-dilatancy relation on some assumption also is derived which is comparable with Rowe's stress-dilatancy relation. By test results, the dilatancy plot (cl/~rz) against (1 +Sv/8 ~1) at the point of failure strength lay very close to a straight line. The authors tried to account for this stress-dilatancy relation inducing the factor •. (Appl. Mech. Rev. 1970.)
51.
K . L . Lee and H. Bo Seed. Undrained strength of anisotropically consolidated sand. J. Soil Mech. Fndns Div. ASCE, 96, SM2, Proc. Paper 7136, 411-428 (Mar. 1970). The strength of triaxial test specimens of saturated sand was investigated over a wide range of density, confining pressure, and anisotropic consolidation stress conditions. It was found that for any one initial density, the volume changes which occurred during consolidation were a unique function of the major principal stress, and were independent of the minor principal stress on the sample. The stress-strain curves and strengths determined from the drained tests on initially identical samples consolidated to the same minor principal stress were almost independent of the principal consolidation stress ratio Kc. However, the undrained strength increased with increasing Kc ratio. At low confining pressures the undrained strength followed the same pattern as previously established for isotropically consolidated undrained tests. For high pressures and high Ko conditions, the peak undrained strength was relatively high. However, this condition was unstable and required only a minor increase in load to reduce the strength to a lower residual value which was similar to the strength predicted by previously established methods. (Authors' summary.)
52.
E. Lill. Geography and the properties of surfaces. The law of travel and its application to rail traffic. 127 pp. (10 Jan. 1969). Eduard Lill, writing in Vienna in 1891, presented elements of a "law of travel" and the statistical testing of it with empirical data from the Austro-Hungarian Empire in which he anticipates much in current geographic models of spatial interaction. Because of the increasing importance of Lill's ideas, it was thought that a translation of his "Law of Travel and Its Application to Rail Traffic" would be appropriate. A commentary on the work is also provided. Essentially, Lill has provided one form of gravity model including intervening opportunities. (U.S. Gov. Res. Dev. Rep., 10.8.69, AD-688453.)
53.
V. Malakhov. Tests of Ural 375 K truck under conditions of the far north. Trans. of Automobilnyi Transport (USSR). 9 pp. (17 March 1969). The Ural-375 K is a modification of the basic Ural-375 V motor vehicle, modified for operation in polar climatic conditions. Modifications included motor pre-heaters, polyurethane foam curtain in front of radiator, independent window heaters, heated battery storage compartment, freeze proof tires and other rubber articles, freeze proof electrical insulation, and special oils and lubricants designed to operate at down to - - 6 0 ° C. It was found in tests that the vehicle could be started after 30 minutes of preheating, and that operating temperatures stabilized at normal levels within 35 to 40 minutes of operation. The vehicle performed generally satisfactory. (U.S. Gov. Res. Div. Reo., 10.8.69, AD-688064.)
ABSTRACTS of two counterrotating rotors which give forward and backward thrust to the vehicle. When both rotors are made to turn in the same direction, the vehicle will move laterally; however, there is no provision for steering when the vehicle is moving laterally. Trafficability tests with the marsh screw were performed to determine its performance on three soil types: sand, clay, and silt. Repetitivepass tests and speed tests were conducted on clay and sand; towing tests on clay, silt, and sand; slope-climbing tests on sand; and obstacle tests on silt, for comparison. Tests with an M29C weasel were conducted and performance curves from previous test programs were utilized. (U.S. Gov. Res. Dev. Dep., 10.8.69, AD-450621.)
49.
J . K . Kouwenhoven. Spring cultivations and wheeltracks. J. agric. Engng Res. 15 (1), 17-26 (1970). During spring cultivations the final part of the increase in pore space resulting from ploughing is often lost by the amount of driving over the soil. In order to prevent heavy compaction of the loose soil and accompanying deep wheeltracks the wheels are often enlarged by the use of cagewheels. This brings on more shallow but much wider tracks, resulting in an increased loss of loose soil. This should be prevented if a large quantity of loose soil is needed (e.g. potatoes) by using rather narrow tyres and dozing the loose soil aside in front of the wheels. For shallow even seedbeds (e.g. sugar-beet) however tyres and cagewheels or preferably wide cagewheels without tyres should be used. (Author's summary.)
50.
K. Kubota and T. Sato. A study on the stress-dilatancy relation of a sand sample. Proc. Sixteenth Japan National Congress for Applied Mechanics, Tokyo, Oct. 19-20, 1966, 173-179 (Dec. 1967). A theoretical and experimental study of the nature of deformation of a sand sample when tested in the triaxial apparatus is presented, and a new stress-dilatancy relation on some assumption also is derived which is comparable with Rowe's stress-dilatancy relation. By test results, the dilatancy plot (cl/~rz) against (1 +Sv/8 ~1) at the point of failure strength lay very close to a straight line. The authors tried to account for this stress-dilatancy relation inducing the factor •. (Appl. Mech. Rev. 1970.)
51.
K . L . Lee and H. Bo Seed. Undrained strength of anisotropically consolidated sand. J. Soil Mech. Fndns Div. ASCE, 96, SM2, Proc. Paper 7136, 411-428 (Mar. 1970). The strength of triaxial test specimens of saturated sand was investigated over a wide range of density, confining pressure, and anisotropic consolidation stress conditions. It was found that for any one initial density, the volume changes which occurred during consolidation were a unique function of the major principal stress, and were independent of the minor principal stress on the sample. The stress-strain curves and strengths determined from the drained tests on initially identical samples consolidated to the same minor principal stress were almost independent of the principal consolidation stress ratio Kc. However, the undrained strength increased with increasing Kc ratio. At low confining pressures the undrained strength followed the same pattern as previously established for isotropically consolidated undrained tests. For high pressures and high Ko conditions, the peak undrained strength was relatively high. However, this condition was unstable and required only a minor increase in load to reduce the strength to a lower residual value which was similar to the strength predicted by previously established methods. (Authors' summary.)
52.
E. Lill. Geography and the properties of surfaces. The law of travel and its application to rail traffic. 127 pp. (10 Jan. 1969). Eduard Lill, writing in Vienna in 1891, presented elements of a "law of travel" and the statistical testing of it with empirical data from the Austro-Hungarian Empire in which he anticipates much in current geographic models of spatial interaction. Because of the increasing importance of Lill's ideas, it was thought that a translation of his "Law of Travel and Its Application to Rail Traffic" would be appropriate. A commentary on the work is also provided. Essentially, Lill has provided one form of gravity model including intervening opportunities. (U.S. Gov. Res. Dev. Rep., 10.8.69, AD-688453.)
53.
V. Malakhov. Tests of Ural 375 K truck under conditions of the far north. Trans. of Automobilnyi Transport (USSR). 9 pp. (17 March 1969). The Ural-375 K is a modification of the basic Ural-375 V motor vehicle, modified for operation in polar climatic conditions. Modifications included motor pre-heaters, polyurethane foam curtain in front of radiator, independent window heaters, heated battery storage compartment, freeze proof tires and other rubber articles, freeze proof electrical insulation, and special oils and lubricants designed to operate at down to - - 6 0 ° C. It was found in tests that the vehicle could be started after 30 minutes of preheating, and that operating temperatures stabilized at normal levels within 35 to 40 minutes of operation. The vehicle performed generally satisfactory. (U.S. Gov. Res. Div. Reo., 10.8.69, AD-688064.)