Penetration devices

Development of specific penetration devices, either incorporated into the CPT or individually used, have further expanded the capabilities of penetration tests, resulting in subsequent refinement of soil profiling. They include the dilatometer (DMT [Marchetti, 1975,1980 Marchetti and Crapps, 1981 Lutenegger, 1988]), seismic cone (Campanella and Robertson, 1984 Campanella et al., 1986 Baldi et al., 1988), acoustic cone (Villet et al., 1981, Massarch, 1986), lateral stress cone and lateral stress cell (measurement of lateral stress on the cone shaft—Morrisson, 1984 Huntsman, 1985 Huntsman et al., 1986 Baligh et al., 1988), vibratory cone (evaluation of susceptibility of cohesionless soils to liquefaction— Sasaki et al., 1984), and pressure-cone (Jezequel et al., 1982 Hughes and Robertson, 1985 Whiters et al., 1986). 

The development of a mechanical process for producing felt is dated to 1820 and has been attributed to J.R. Williams (3). The transition from interlocking fibers by working the scales on adjacent fiber surfaces against one another to working the fibers by a scaled external member in the form of a barbed penetrating device took place during the last quarter of the nineteenth century. This transition was made possible by the development of the mechanisms and machinery to produce needled nonwovens in a factory environment. 

Ruoslahti, E., 2012. Peptides as targeting elements and tissue penetration devices for nanoparticles. Adv. Mater. 24, 3747-3756. 

The radiation and temperature dependent mechanical properties of viscoelastic materials (modulus and loss) are of great interest throughout the plastics, polymer, and rubber from initial design to routine production. There are a number of laboratory research instruments are available to determine these properties. All these hardness tests conducted on polymeric materials involve the penetration of the sample under consideration by loaded spheres or other geometric shapes [1]. Most of these tests are to some extent arbitrary because the penetration of an indenter into viscoelastic material increases with time. For example, standard durometer test (the "Shore A") is widely used to measure the static "hardness" or resistance to indentation. However, it does not measure basic material properties, and its results depend on the specimen geometry (it is difficult to make available the identity of the initial position of the devices on cylinder or spherical surfaces while measuring) and test conditions, and some arbitrary time must be selected to compare different materials. 

The limitation to disk constmctions with a laser beam reflected at the disk surface is a large drawback, however. This prevents the insensitivity against dust and dirt, which is well known from current optical storage devices with a laser beam reflected after penetration of the transparent substrate. 

The isotope plutonium-238 [13981 -16-3] Pu, is of technical importance because of the high heat that accompanies its radioactive decay. This isotope has been and is being used as fuel in small terrestrial and space nuclear-powered sources (3,4). Tu-based radioisotope thermal generator systems dehvered 7 W/kg and cost 120,000/W in 1991 (3). For some time, %Pu was considered to be the most promising power source for the radioisotope-powered artificial heart and for cardiovascular pacemakers. Usage of plutonium was discontinued, however, after it was determined that adequate elimination of penetrating radiation was uncertain (5) (see PROSTHETIC AND BIOMEDICAL devices). 

As of the mid-1990s, the market for bradyarrhythmia devices is hiUy penetrated in Western countries. Some growth is expected to result from an aging population but, by and large, the market is mature. The market for tachyrhythmia devices, in contrast, is only beginning. 

When tubes are omitted from the tube layout to provide entrance area about an impingement plate, the need for sealing strips or other devices to cause proper bundle penetration by the shell-side fluid is increased. 

Another major difference between the use of X rays and neutrons used as solid state probes is the difference in their penetration depths. This is illustrated by the thickness of materials required to reduce the intensity of a beam by 50%. For an aluminum absorber and wavelengths of about 1.5 A (a common laboratory X-ray wavelength), the figures are 0.02 mm for X rays and 55 mm for neutrons. An obvious consequence of the difference in absorbance is the depth of analysis of bulk materials. X-ray diffraction analysis of materials thicker than 20—50 pm will yield results that are severely surface weighted unless special conditions are employed, whereas internal characteristics of physically large pieces are routinely probed with neutrons. The greater penetration of neutrons also allows one to use thick ancillary devices, such as furnaces or pressure cells, without seriously affecting the quality of diffraction data. Thick-walled devices will absorb most of the X-ray flux, while neutron fluxes hardly will be affected. For this reason, neutron diffraction is better suited than X-ray diffraction for in-situ studies. 

Another important factor is the corrosiveness of the adhesive. This may be especially important in those cases where the PSA has direct contact with the bare wire, the electronic component, or the silicon wafer in a dicing operation. In those cases where an electrical current is running through the device, electrolytic corrosion processes may occur, especially if moisture can penetrate into the adhesive or bond line. 

An air curtain is to be used in the doorway of an industrial building to prevent the penetration of cold air into the building. The task is to dimension this air curtain device for the following climatic conditions ... 

The plume airflows (q ) are determined as described in Section 7.5. The turbulent mixing iqi,) between zones and the penetration of the plume airflows iq, h,n) through the supply airflow patterns must be determined specially for the air distribution method and devices used as well as the locations of plumes and supply air devices. 

Simple models for louvers and other solar protection devices are based on a statement of constant reduction of the solar radiation flux on the window. A common assumption is that a louver is controlled so that no direct light can penetrate into the room. 

---