Neck-down

Fig. 5. Two-stage light gas gun showing the piston and H projectile where M = propellant charge and 1 = light gas (a), before firing (b), after firing propellant charge (c), as piston nears necked-down mouth of the launch tube (d), after completion of firing cycle. Piston is removed from neck of launch...

In 1606 Gioavanni Battista della Porta of Naples performed two experiments that formed the basis for steam engines. He proved that steam could develop pressure by expelling water from a sealed container. In the next experiment a steam-filled flask was inrmersed neck down in water. As the cooling steam condensed, water flowed upward into the flask, proving that a vacuum had been created. 

Small and long specimens of tensile bar shape specimens have their major change in dimensions in the necked-down section. The specimen is mounted between a pendulum head and crosshead clamp on the pendulum of an impact tester. The pendulum is released and it swings past a fixed anvil that halts the crosshead clamp. The pendulum head continues forward, carrying the forward portion of the ruptured specimen. The energy loss (tensile impact energy) is recorded, as well as whether the failure appeared to be of a brittle or ductile type. 

Necking Also called neck-down or neck-in. 

Apply 0.5% bleach solution gently by blotting or using hands to apply over all areas of the skin starting from the neck down. Do not rub solution too vigorously as this may irritate skin. If bleach solution is not available, go directly to Step 8. 

Scabies Apply thin layer from neck down and wash off after 10 hours. Pediculosis Apply shampoo to hair add water after 4 min. then rinse and towel dry. 

One gram of silver 0-alumina crystals is placed in a Vycor tube with a 1-cm id and 20 cm long and closed at one end. Three grams of gallium and 4 g of iodine are added, and the Vycor tube is necked down near the middle in preparation for sealing off. The tube is evacuated with a mechanical pump to <1 torr pressure and sealed. The sealed tube is placed in a cold furnace and then heated to... 

Poly(ethylene) wrapping, bag film, or other polymer that can be cold drawn without necking down in thin (0.05-0.2 nm) film form. Approximately 5 to 10 cm2 is required. 

It is recommended that permethrin 1% cream rinse (Nix) be applied undiluted to affected areas of pediculosis for 10 minutes and then rinsed off with warm water. For the treatment of scabies, a single application of 5% cream (Elimite) is applied to the body from the neck down, left on for 8-14 hours, and then washed off. Adverse reactions to permethrin include transient burning, stinging, and pruritus. Cross-sensitization to pyrethrins or chrysanthemums has been alleged but inadequately documented. 

Recent concerns about the toxicity of lindane have altered treatment guidelines for its use in scabies the current recommendation calls for a single application to the entire body from the neck down, left on for 8-12 hours, and then washed off. Patients should be retreated only if active mites can be demonstrated, and never within 1 week of initial treatment. 

Lindane (Kwell, etc) is available as a shampoo or lotion. For pediculosis capitis or pubis, one application of 30 mL of shampoo is worked into a lather and left on the scalp or genital area for 5 minutes and then rinsed off. No additional application is indicated unless living lice are present 1 week after treatment. Then reapplication may be required. Recent concerns about the toxicity of lindane have altered treatment guidelines for its use in scabies the current recommendation calls for a single application to the entire body from the neck down, left on for 8-12 hours, and then washed off. Patients should be retreated only if active mites can be demonstrated, and never within 1 week of initial treatment. 

The bottle exits the filler and enters the corker where it is corked with a natural cork that has been exposed to a high SO2 content atmosphere prior to being fed to the corking machine. In the corker, as the bottle is put into place, a vacuum is drawn of approximately twenty-seven inches (680 mm) of mercury on the bottle headspace. The cork then is inserted into the neck of the bottle against this partial vacuum. The bottle leaves the enclosed room, a foil is placed on the neck, it is labeled, cased, and stored neck down until ready for release by the winery. 

Bob sees that Miss Muxdroozol sometimes shivers. If it doesn t get warmer soon, we can try to build a fire. The thin cotton fabric of her shirt barely hides her tiny goose bumps that seem to travel in concentric waves from her neck down. 

Figure 2.19 Failure of a connecting rod bolt in a diesel engine. In (a), the failed bolt is the upper one, having necked down in a nominally larger cross-sectional area. The lower bolt is another removed from the engine in unstretched condition. In (b), the stretched region of the bolt is shown, with cracks that have opened up during bolt tensioning and subsequent operation. (Reprinted with permission from ASM International. All rights reserved www.asminternational.org)...

Tensile strength The pulling stress, in psi, required to break a given specimen. Area used in computing strength is usually the original, rather than the necked-down area. 

In the kitchen, I found Giorgio in the near darkness, asleep with his top half sprawled on the table, and the bench taking his weight. I made enough noise with the ladle to waken him. He sat up, showing no surprise at seeing me clad in black from the neck down. 

Assuming a fixed band structure (the rigid band model), a decrease in the density of states is predicted for an increase in the electron/atom ratio for a Fermi surface that contacts the zone boundary. It will be recalled that electrons are diffracted at a zone boundary into the next zone. This means that A vectors cannot terminate on a zone boundary because the associated energy value is forbidden, that is, the first BZ is a polyhedron whose faces satisfy the Laue condition for diffraction in reciprocal space. Actually, when a k vector terminates very near a BZ boundary the Fermi surface topology is perturbed by NFE effects. For k values just below a face on a zone boundary, the electron energy is lowered so that the Fermi sphere necks outwards towards the face. This happens in monovalent FCC copper, where the Fermi surface necks towards the L-point on the first BZ boundary (Fig. 4.3f ). For k values just above the zone boundary, the electron energy is increased and the Fermi surface necks down towards the face. 

To produce the fine tip of the micropipette necessary for inserting into a cel 1, a microcapillary is put under tension in the axial direction and then the glass is heated near the middle until it becomes red-hot. Remarkably, as the heated glass flows and the microcapillary is thus stretched and necks down to the extremely fine diameter required (much less than the thickness of a human hair), the inside hole is maintained (the microcapillary eventually breaks where it was heated, forming two micropipettes). The inside of the micropipette is filled with oil for a pressure probe or filled with a conducting solution for electrical measurements (e.g., Fig. 3-6). 

Figure 1-2 records some typical stress-strain curves for different polymer types. Some polymers exhibit a yield maximum in the nominal stress, as shown in part (c) of this figure. At stresses lower than the yield value, the sample deforms homogeneously. It begins to neck down at the yield stress, however, as sketched in Fig. 11-20. The necked region in some polymers stabilizes at a particular reduced diameter, and deformation continues at a more or less constant nominal stress until the neck has propagated across the whole gauge length. The cross-section of the necking portion of the specimen decreases with increasing extension, so the true stress may be increasing while the total force and the nominal stress...

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