Nape piercing
Somewhat less common are surface anchors, commonly made from surgical implant-grade titanium. A surface anchor has two parts: a base or foot which is inserted under the dermis during the piercing process and which incorporates a stem exposed to the surface, and a decorative disc or ball of jewelry which typically appears flush with the surface of the skin. Surface anchor nape piercings are most commonly found placed symmetrically on either side of the spine at the nape.
Anchor bolt
The force-transfer mechanism is based on bond stresses provided by binding organic materials. Both Ribbed bars and threaded rods can be used and a change of the local bond mechanism can be appreciated experimentally. In ribbed bars the resistance is prevalently due to shear behavior of concrete between the ribs whereas for threaded rods friction prevails.(see also Anchorage in reinforced concrete). Bonded anchors are also referred as "adhesive anchors". The anchoring material is an adhesive (also called "mortar") usually consisting of epoxy, polyester, or vinylester resins. The performance of this anchor's types in terms of 'load-bearing capacity', especially under tension loads, is strictly related to the cleaning condition of the hole. Experimental results showed that the reduction of the capacity is up to 60%. The same applies also for moisture condition of concrete, for wet concrete the reduction is of 20% using polyester resin. Other issues are represented by high temperature behavior and creep response.