Transformations and Two Way Memory Effect Associated with Solution-treatment Temperature

Effect of solution treatment temperature on transformations and two way memory, effect in a Ti- 55.2 wt-%Ni alloy was investigated. The results show that with increasing the solution treatment temperature (T_s), two way memory effect (TWME) decreases continuously and temperatures of martensite and reverse, martensite transformations (MR) rise, but the temperature of R start trans- formation (parent→R) does not change. The results of the internal friction measurements indicate that when T_s=1073 K, internal friction peaks of MR and P→R transformations are larger than those of the specimens after solution-treatments at 973 and 1173 K. With increasing T_s, the de- crease of TWME can be attributed to that the defect stress field caused by the rolling fades out grad- ually and preferential martensite variants, which fit into the defect stress field, decrease. The changes of transformation temperatures and internal friction peaks with T_s are closely related to the change of defect numbers.

TRANSFORMATION CHARACTERISTIC OF TWO WAY SHAPE MEMORY MATERIAL CONSTRAINED BY STRESS

The snap-acting transition and two way shape memory (TWSM) effect have been obtained in a TWSM spring made of Ni51Ti49 alloy using the constrained effect of stress on driving force of TWSM material.When the snap-acting transition has been realized:M_s= M_f and A_s=A_f;hysteresis is rectangular,the height (TWSM effect) and width (hysteresis) of the rectangle can be readjusted by means of constrained stress.The results of resistance measurments show that,the snap-acting TWSM effect mentioned above was supplied mainly from the transformation of P←→R.The thermodynamic model has also been proposed to ac- count for the snap-acting transformation.

A New Two Way Stop Plate in Loom Equipment

This design offer the two way stop used plate on warp. It is applicable to textile equipment, especially for loom equipment. The characteristics are that there are two similar long grooves in the different sides of the yarn hole, so that it can be used in two way and the life cycle is twice as long as that of the present one.

Safety effectiveness of roadway conversion with a two way left turn lane

In urban or suburban areas with a large number of access points, four-lane undivided highways are prone to crashes due to left-turning and through movements in a single lane. Many studies recommended expensive countermeasures like conversion from undivided to divided road with physical separation. One inexpensive alternative is reconfiguring the existing roadways by either increasing or decreasing the number of lanes. This study investigated the safety impact of converting four lane undivided roadways （4U） to five lane undivided roadways （ST） with a two way left turn lane （TIkrLTL）. This study used Empirical Bayes method to determine the safety impact of this inexpensive countermeasure. In this study, data from eight sites from Louisiana were collected for investigation, and site- specific crash modification factor （CMF） values were calculated. Although ST is usually not preferable due to its exposure of higher number of crashes in the existing literature, the findings of the current study indicated a positive safety impact. The benefit-cost ratio of this conversion ranges from 97 to 379. The current findings indicate that conversion of 4U to 5T is a feasible inexpensive solution for urban roadways with lower volume and a limited number of driveways.

Stress-induced deformation at A_p～M_p and thermal cycling behavior of Cu-Al-Ni single crystals

Stress induced deformation in A p～ M p and concomitant shape recovery behavior of Cu 13.4Al 4.0Ni single crystals were studied. Abnormal high stress induced deformation exists in A p～ M p under the conditions of either heating with load or cooling with load. The recovered deformation is successively composed of four parts, the recoveries from superelasticity, normal reverse transformation, thermally activated reverse transformation of partially stabilized martensite and reverse transformation of stabilized martensite by over heating. With increasing cycling number, the recovery part from normal reverse transformation decreases, while that from reverse transformation of stabilized martensite by over heating increases, which shows a typical stabilization of martensite.

NONHYDROSTATIC NUMERICAL SIMULATION FOR THE“96.8”EXTRAORDINARY RAINSTORM AND THE DEVELOPING STRUCTURE OF MESOSCALE SYSTEM

During the period of 3—5 August 1996(for short “96.8”),an extraordinary rainstorm event occurred in Henan,Hebei and Shanxi Provinces in China,resulting in severe flood catastrophe. Synoptic analyses indicated that the stable gross col field and the interaction between a northward moving typhoon(down into low pressure)and its east lateral Pacific subtropical high were the large-and meso-scale circulation conditions of the “96.8” extraordinary rainstorm.The mesoscale typhoon-low and its specific dynamical and thermodynamical structures were directly related to this rainstorm event.The nonhydrostatic version of mesoscale numerical model MM5 was used to conduct investigation of numerical simulation for this case.The simulation with the full physical processes of nonhydrostatic version MM5 was basically possessed of a capability to reproduce the genesis,development and evolution of the large-scale and meso-α scale synoptic systems.The simulative results using a two-way interactive nesting procedure revealed that the typhoon-low was possessed of an intensive coupled mechanism between the dynamical and thermodynamical fields, namely,the developing typhoon-low was possessed of a structure of the.cyclonic vorticity column with warm center and high humidity,the vorticity column on the lower levels was the moist convective instability and negative moist potential vorticity structure:the intensive ascending vertical motion and the intense divergence on upper levels and intensive convergence on the lower levels as well as the development of the convective cloud cluster were intercoupling:the intense southern wind jet companied by the typhoon-low was not only the interaccompanying and intercoupling condition of the development and maintenance of the typhoon-low and convective cloud cluster,but also was the transportable belt of the moisture source and heat energy of the “96.8”extraordinary rainstorm.The analysis of simulative results of precipitation indicated that the distribution of the rainfall belt and rainfall rate was basically consistent with that of the observation in spite of some rainfall centers less or larger than those of the observation for coarse or fine mesh domain,respectively.