The classical brittle fracture mechanisms fail to account for the mechanical properties of glasses, but widespread evidence plastic flow in all glass phenomena even at room temperature suggests that this might provide a consistent strength theory. This first paper discusses flow, evaluates stresses by re-interpretation indentation hardness figures, and shows are much lower than theoretical cohesive strengths.

Certain male moths flying upwind toward a scent-producing female appear to be guided anemotactically by optomotor reactions the ground pattern. Loss of odor stimulus changes anemotactic angle from into wind across with left-right reversals.

ABSTRACT. The zigzagging behaviour of male Plodia interpunctella flying up a plume sex pheromone was investigated in horizontal wind tunnel by detailed analysis the moths' ground tracks, groundspeeds, orientations and airspeeds. moths ‘homed in’ on source progressively reducing airspeed turning more into wind, thereby groundspeed distance between track reversals so narrowing down their zigzags (Fig. 16). Track angles times were unaffected. Removing wind‐borne while moth along it confirmed...

It is usual to regard glass as a purely brittle solid and this has been taken for granted in almost all past papers on the mechanical strength, static fatigue, ageing properties of glasses. However, present note approach rejected being incompatible with experimental evidence plastic flow glass, incapable explaining strengths observed. Instead completely new attempted which treated an elastic-plastic complete theory strength developed. The summarizes contents three soon be published develop...

This paper describes a tensile testing machine for microscopic specimens. It can apply loads in the range from 1 mgf to 400 gf specimens having cross-sectional areas down 10-7 mm2. Specimen extensions few angström units 15 mm be measured and, at constant temperature, random errors extension measurement system are less than 5 Å (5 × mm). The employs torsion balance and mirror-autocollimating telescope detect extensions. Since it depends wholly on mechanical optical principles is practically...

ABSTRACT Oviparae of Megoura viciae Buckton release a sex pheromone from numerous plaques on their hind tibiae. Adult males react to this scent in variety ways: inactive are aroused; already walking orient the odour source; and copulatory activity is increased. These responses only evoked within few centimetres stimulus source decline rapidly as diluted. Male responsiveness unchanging throughout light phase (of LD 12 : 12), although they show marked circadian locomotor rhythm. Their...

The strength of glass is known to be very variable and also affected by the condition surface. By improving a technique decoration with sodium, due originally Andrade, elaborate crack systems have been revealed on surface drawn glasses. These are correlated with, may control, mechanical glass. They appear indicate existence tension layer cracks seem 100 200 A wide probably at least 1000 deep. Cracks can initiated local abrasion, but this not only cause. for examination thin films...

The problems of the mechanical testing whiskers and thin films having gauge lengths down to 0.2 mm cross-sections as low 8 × 10-7mm2 are discussed. A machine is described which gives load-strain curves for such specimens with minimum load increments 0.5 mg f extension readings repeatable 0.019 μ. torsion balance applies measures strain obtained by a null method using marker special optical arrangement in projection microscope. number design features incorporated ensure high stability.

Most state-of-the-art bipedal robots are designed to be anthropomorphic and therefore possess legs with knees. Whilst this facilitates more human-like locomotion, there implementation issues that make walking straight or near-straight difficult. have move a constant bend in the avoid singularities at knee joints, keep centre of mass height for control purposes. Furthermore, having on leg increases design complexity as well weight leg, hindering robot's performance agile behaviours such...

In 1978 we reported the results of an analysis zigzagging behaviour male Plodia interpunctella flying up a plume sex pheromone (Marsh et al. , 1978). Since then have discovered that, owing to two technical faults, used incorrect time base in analysing videotape records moths' tracks. The original tapes now been re‐analysed and full revision paper is being prepared which shows that only one important conclusion must be changed. Meanwhile has cited at least twice (Schöne, 1980, p.236; Murlis...

The first part of the paper describes a simple and yet precise clamp for strip hinges which facilitates construction flexure hinges. use this clamping system in various is described it believed that fairly general application. second discusses merits single hinge, becomes especially to construct by method, shown limited rotations often superior performance well-known cross hinge. It suggested more frequent as

This work proposes a new swing controller for semi-powered low impedance transfemoral prostheses that resolves the issue of potentially competing inputs between artificial assistive power and user-sourced power. Rather than add as an exogeneous input, control approach uses to modify homogeneous portion shank dynamics, therefore need not construct or curate input is coordinated with user input. The implemented requires single parameter at given walking speed, where value function determined...