Quick application/release nut with engagement indicator

A composite nut is shown which permits a fastener to be inserted or removed from either side with an indicator of fastener engagement. The nut has a plurality of segments, preferably at least three segments, which are internally threaded, spring loaded apart by an internal spring, and has detents on opposite sides which force the nut segments into operative engagements with a threaded member when pushed in and release the segments for quick insertion or removal of the nut when moved out. When the nut is installed, end pressure on one of the detents presses the nut segments into operative engagement with a threaded member where continued rotation locks the structure together with the detents depressed to indicate positive locking engagement of the nut. On removal, counterclockwise rotation of the nut relieves the endwise pressure on the detents, permitting internal springs to force the detents outward and allowing the nut segments to move outward and separate to permit quick removal of the fastener

Alignment positioning mechanism

An alignment positioning mechanism for correcting and compensating for misalignment of structures to be coupled is disclosed. The mechanism comprises a power screw with a base portion and a threaded shank portion. A mounting fixture is provided for rigidly coupling said base portion to the mounting interface of a supporting structure with the axis of the screw perpendicular thereto. A traveling ball nut threaded on the power screw is formed with an external annular arcuate surface configured in the form of a spherical segment and enclosed by a ball nut housing with a conforming arcuate surface for permitting gimballed motion thereon. The ball nut housing is provided with a mounting surface which is positionable in cooperable engagement with the mounting interface of a primary structure to be coupled to the supporting structure. Cooperative means are provided on the ball nut and ball nut housing, respectively, for positioning the ball nut and ball nut housing in relative gimballed position within a predetermined range of relative angular relationship whereby severe structural stresses due to unequal loadings and undesirable bending moments on the mechanism are avoided

The Gregory-Laflamme instability and non-uniform generalizations of NUT strings

We explore via linearized perturbation theory the Gregory-Laflamme instability of the NUT string (i.e the D=4 Lorentzian NUT solution uplifted to five dimensions). Our results indicate that the Gregory-Laflamme instability persists in the presence of a NUT charge $n$, the critical length of the extra-dimension increasing with $n$ for the same value of mass. The non-uniform branch of NUT strings is numerically extended into the full nonlinear regime.Comment: 10 pages, 3 figure

Development of an ultra-low-shock separation nut

The technical problems encountered in the development of an advanced separation nut design are described. The nut is capable of sustaining a large preload and releasing that load with a low level of induced pyrotechnic shock, while demonstrating a tolerance for extremely high shock imposed by other pyrotechnic devices. The analysis of the separation nut was performed to acquire additional understanding of the phenomena affecting operation of the nut and to provide quantitative evaluation of design modification for aerospace applications

Tube joint leak repair coupling

Tube joint leak repair coupling consists of 2 split seals, 1 male split nut, 1 female split nut, and two aligning pins. Each split nut consists of 2 half-shell sections which, when engaged, are held together by a dovetail joint and an aligning pin

Prevalence of Oral Cancer in Adolescents Related to Areca (Betel) Nut Chewing, Using Tobacco and Other Additives in Saipan, Northern Marianas Islands: A Review of Literature

Oral cancer can involve the lip, tongue, mouth and pharynx. It is the sixth most prevalent cancer worldwide. One of the leading causes of Oral Cancerin the Commonwealth of the Northern Mariana Islands (CNMI) is chewing betel nut with tobacco and other additives. The International Agency for Research on Cancer (IARC) linked areca nut, betel quid with tobacco and betel quid without tobacco as carcinogenic to humans. Areca nut, also known as betel nut comes from the areca palm tree. The use of areca nut is common throughout the Pacific, and is widespread in Papua New Guinea, Solomon Islands, Guam, the Federated States of Micronesia, Palau, CNMI and the Marshall Islands. The objective of this review is to gather published data related to oral cancer in adolescents as a result of chewing betel nut, using tobacco and other additives; and whether these studies address prevalence in adolescents in Saipan, CNMI. The literature searches were done electronically on World Health Organization, Journal of Dental Research, Center for Pacific Islands Studies/University of Hawai\u27i, IARC websites and Google search using keywords. A cross-sectional survey study (Oakley at el 2005) of 169 students shows 63.4% use areca nut regularly. It was more prevalent among male (73%) than females (54%). The mean age in starting to chew areca nut was 12.0, while some starting at age 10 or younger. The betel quid mixture included powdered lime and pepper betel leaf. Tobacco use was also widely prevalent among schoolchildren. Oral pathological lesions were noted during screening examinations. Areca (betel) nut chewing with the use of tobacco and other additives is increasingly observed among adolescents in Saipan. Further studies are needed on the prevalence of oral cancer in adolescents related to areca nut chewing, using tobacco and other additives and how to decrease oral cancer risk in this age group

Inner-most stable circular orbits in extremal and non-extremal Kerr-Taub-NUT spacetimes

We study causal geodesics in the equatorial plane of the extremal Kerr-Taub-NUT spacetime, focusing on the Innermost Stable Circular Orbit (ISCO),and compare its behaviour with extant results for the ISCO in the extremal Kerr spacetime. Calculation of the radii of the direct ISCO, its Kepler frequency, and rotational velocity show that the ISCO coincides with the horizon in the exactly extremal situation. We also study geodesics in the strong {\it non}-extremal limit, i.e., in the limit of vanishing Kerr parameter (i.e., for Taub-NUT and massless Taub-NUT spacetimes as special cases of this spacetime). It is shown that the radius of the direct ISCO increases with NUT charge in Taub-NUT spacetime. As a corollary, it is shown that there is no stable circular orbit in massless NUT spacetimes for timelike geodesics.Comment: 15 pages, 3 figures, modified version, accepted for publication in Eur. Phys. J.