Dynamic force analysis of a six-link planar mechanism

In this paper is studied a vibratory conveyor that is placed on an elastic base. Using the closed contours method it was determined the system that needs to be solved to obtain graphical representation for the generalized coordinates determining the position of the mechanical system elements. The shaking conveyor represents the chase hanged or supported to the fixed section. The chase commits oscillating motions hereupon the cargo which is in the chase, migrates concerning to the chase. The nature of the flow and its parameters are determined by the nature of the oscillating committed by the chase. Installation causes fluctuations fixed tray. Uniformly distributed load on the tray acts in each element of the mechanism. A proper dynamic model has been developed within MSC ADAMS and Maple 18. Simulation tests have been carried out and results are discussed to validate the proposed design solution.

Patrones de emergencia de Odonata (Insecta) en un hábitat lótico de Cuba oriental

The emergence patterns of tropical odonates (dragonflies and damselflies) are scarcely known. We studied the emergence patterns of odonates in a freshwater lotic system in Giro, Northern Santiago de Cuba, between January and December 2008. We visited the locality between 09:00 and 14:00, on a weekly basis, and collected exuviae from a fixed section (8 x 1 m2) offshore, along the riparian vegetation. We collected data on species composition and, for each species, abundance, relative biomass and emergence pattern. We collected 443 exuviae belonging to 22 species: seven Zygoptera and 15 Anisoptera. Half of the annual Odonata emergence took place in the dry season (December to March) with the highest value in February (25 %). For species for which we found seven or more exuviae per month, Enallagma coecum and Macrothemis celeno tended to be a synchronal emergence. We also found temporal segregation of the emergence pattern between M. celeno and Protoneura capillaris, Neoneura maria, Progomphus integer and Scapanea frontalis. These differences were probably related to the highest annual fluctuations of temperature, relative humidity and number of rainy days per month. We concluded that there is an asynchrony and heterogeneity in Odonata emergence times in the studied freshwater lotic system.

A New Continuum Robot With Crossed Elastic Strips: Extensible Sections With Only One Actuator per Section

We propose a new kind of continuum robot based on crossed elastic strips. The actuator-specified location of the crossover point controls the lengths of the sections, enabling a wider range of configurations than would be possible with traditional fixed-section-length robots. Push-pull actuation of the crossed strips controls the curvature of the sections. We provide a model that describes the resulting configurations in terms of tangent circular arcs of varying lengths. Experiments with a prototype yield tip positions that agree with model predictions with an average error of 4.6% of the robot’s length.

Automorphism groups of rational elliptic surfaces with section and constant J-map

In this paper, the automorphism groups of relatively minimal rational elliptic surfaces with section which have constant J-maps are classified. The ground field is ℂ. The automorphism group of such a surface β: B → ℙ1, denoted by Au t(B), consists of all biholomorphic maps on the complex manifold B. The group Au t(B) is isomorphic to the semi-direct product MW(B) ⋊ Aut σ (B) of the Mordell-Weil groupMW(B) (the group of sections of B), and the subgroup Aut σ (B) of the automorphisms preserving a fixed section σ of B which is called the zero section on B. The Mordell-Weil group MW(B) is determined by the configuration of singular fibers on the elliptic surface B due to Oguiso and Shioda [9]. In this work, the subgroup Aut σ (B) is determined with respect to the configuration of singular fibers of B. Together with a previous paper [4] where the case with non-constant J-maps was considered, this completes the classification of automorphism groups of relatively minimal rational elliptic surfaces with section.

Research against the Effect of Inertia Loads on Dynamic Responses of a Simply Supported Beam

In order to quantitative study the loads inertia on the effect of dynamic response on a simply supported beam, a simply supported beam with a fixed section forms and different span has been calculated under two different loading modes including moving load and moving mass by numerical method by MATLAB program. The calculated results shows the exact solution of beam vibration differential equation can be calculated and a quantitative description can be made about the load inertia effects on dynamic responses of the simply supported beam. These results provide guidance to the project practice.

Numerical Simulation of Mechanical Behavior on Landslides Triggered by Heavy Rainfall

Deformation instability of slope due to rain was one of the most common geological disasters. Speaking from the mechanism, the destructive action and triggering action of rainfall affected the stability of slope itself, which made the slope deform and even lead to instability. June 28, 2010, Guanling in Guizhou province a large landslide occurred which triggered by continuous heavy rainfall, it caused that in two village-groups 107 villagers were buried, all the tragedy of houses were completely destroyed. Using finite element software ANSYS to simulate the mechanical behavior of the landslide, to analyze the deformation mechanism, we got that the large landslide deformation mechanism was a complex mechanical geological process. From the analysis of interaction between soil and rock, the landslide showed complex mechanical geological features. As rainfall increased the strength of unsaturated soil and weak intercalation reduced, this strengthened the role of the slope deformation and failure. The lock-fixed section first appeared brittle fracture, then that brought shear failure to the creeping section. The interaction between lock-fixed section and creeping section was the key of slope failure.

Microwave fixation of large tissue

Chemical fixation of large biological tissues in electron microscopy has a disadvantage that fixative doesn’t penetrate well into the deeper part of the tissue. My experience suggests that the poor penetration by chemical fixation can be improved by microwave fixation. Temperature raise caused by microwave irradiation is regulated by the cold bath on the floor of the oven. This paper shows that microwave fixation is readily practicable together with conventional fixation. Well-fixed section with an area as large as 1×5mm is observable and the details of morphological structures are preserved quite well in it.A commercial microwave oven (National Microwave Oven Model NEM-335,2.45GHz 500/180W) was used for the microwave fixation. Irradiation period was controlled by Omuron H5cN-AN. Young mouse kidney and brain were used. The tissue in a glass vial placed in the cold bath was immersed in the mixture of 2% paraformaldehyde and 0.5% glutaraldehyde in phosphate buffer (pH7.4),followed by microwave irradiation for 10 sec. twice.

Stiffness and Friction Force Measurements on a Freight Car Truck from Quasi-Static Tests

A conventional three-piece truck with load sensitive friction snubbing was tested as a complete assembly with its wheels resting on a fixed section of rail and with loads applied through a fixture that duplicated the body bolster at the truck bolster interface. The purpose of the testing was to determine the stiffness and friction forces of the truck under vertical, lateral, and roll moment loading conditions. Loads were varied to cover a range of car gross weight conditions. The test was quasi-static in that load application was varied at sinusoidal rates of 0.1 or 0.2 Hertz to minimize errors in spring rate measurement caused by friction snubber forces. The desired stiffness and friction force data were obtained in terms of system rather than component properties and are consequently more directly usable in mathematical models. The roll test data were particularly useful because separate spring rates were obtained for the different conditions of center plate seated, center plate rocking, and side bearing contact. Because of the sinusoidal method of load application, it was possible to obtain system spring rates with the friction snubbers static and sliding.

AN EVALUATION OF STERNAL ASPIRATION AS AN AID IN DIAGNOSIS OF THE MALIGNANT LYMPHOMATA

Neither diagnostically significant features nor consistent abnormalities of other character were demonstrated in the specimens of sternal marrow obtained in 15 cases of Hodgkin’s disease. With improvements in technic, particularly in patients presenting clinical evidence of bone or bone marrow involvement, the procedure might become more valuable. As an aid in diagnosis in cases of obscure malignant lymphoma, sternal aspiration is likely to prove of greatest value in cases of lymphosarcoma. In 7 of 10 proved cases, abnormal lymphocytic cell types were encountered and in 3 instances bone marrow infiltrations were demonstrated in fixed section preparations. The latter were felt to be diagnostic of lymphosarcoma. In 2 cases of follicular lymphoma the specimens of sternal marrow presented no striking abnormalities. However, because of the apparently close relationship which this disease bears to lymphosarcoma it is felt that study of a larger number of cases may prove the procedure of some diagnostic value.

U.S. Patent Specifications

In an aircraft the combination with an engine and a propeller of streamlining devices comprising a streamlined spinner section rotatably mounted on the engine shaft forward of the propeller, means to inhibit rotation of said spinner with the shaft, a streamlined section movable with the propeller and constituting a continuation of the streamlining of the spinner section, a streamlined fixed section secured to the engine and constituting a continuation of the spinner and rotatable streamlined section and a cowling surrounding and secured to the engine and formed to provide a narrow air inlet slot between said cowling and the fixed section to admit a limited flow of air about the engine and outlets for the exit of said air, said cowling including outlets for the exit of substantially all the air entering said inlet slot.