摘要:
Provided is a method of making durable hydrophilic and hierarchical structures containing nano and micro features used as dry adhesives. The method includes introduction of hydrophilic, nanostructured features on the micro-scale tips of fibrillar arrays through UV/Ozone (UVO) and oxygen plasma treatment; the method also includes further coating of the hierarchical structure with a polyelectrolyte via electrostatically-driven self-assembly to improve the hydrophilic stability of the treated fibril tip surfaces.
摘要:
A perching mechanism is developed which comprises shape-memory components capable of undergoing motions that render the perching effect. This mechanism can provide unmanned air vehicles with versatile, bird-like landing capabilities on surfaces of different types and orientations.
摘要:
The present invented mechanism comprises more than two (legs) with phase difference (like polygon-shape, ellipse-shape, and etc) between their rotation angles to produce pre-loading for improved adhesion. Two rigid plates covered with adhesives are attached to each phase difference wheel. Each plate connects to the wheels via a hinge embodying a torsional spring, which forces the plate back to its original position after each contact with surface. The phase difference wheels are made of elastic materials for application of controlled pre-loads at contact surfaces during locomotion. The difference between height and width of each wheel as well as the elastic properties of the materials determine the pre-load pressure applied during locomotion. The pre-load pressure is not strongly dependent on the orientation of locomotion. This enables locomotion in vertical, inclined and even upside-down orientation and also in the non-gravity environment.
摘要:
This invention relates to appliqué film for paint replacement application on aircraft and other surfaces. This system comprises a carrier backing film with patterned hybrid pressure sensitive adhesives (PSAs), with discrete silicone phase within a continuous acrylic phase. The patterned hybrid PSAs exhibit a peel strength between 2 and 8 pound per in (pli) in the temperature range of −65° F. to 285° F. This appliqué film also provides high levels of stability under exposure to weathering effects and fluids applied to exterior aircraft surfaces.
摘要:
Ultra-high-performance cementitious materials are made using suitably functionalized and relatively low-cost carbon nanofibers and graphite platelets. Polyelectrolytes and surfactants are physisorbed upon these graphite nanomaterials in water, and dispersion of nanomaterials in water is achieved by stirring. Stable and well-dispersed suspensions of nanomaterials in water are realized without using energy-intensive and costly methods, and also without the use of materials which could hinder the hydration and strength development of ultra-high-performance cementitious materials. The water incorporating dispersed nanomaterials is then mixed with the cementitious matrix and, optionally, microfibers, and cured following standard concrete mixing and curing practices. The resulting cementitious materials incorporating graphite nanomaterials and optionally microfibers offer a desired balance of strength, toughness, abrasion resistance, moisture barrier attributes, durability and fire resistance.
摘要:
Shaped articles with the inherent capability to evolve in response to at least one of external and internal stimuli are described. These articles comprise at least one solid electrolyte with at least one dissolved salt, and at least one interface which involves a solid electrolytes and a conductive solid. Electric potential gradients, generated within the solid electrolyte by at least one of external and internal stimuli, guide and drive the self-healing and adaptation phenomena. The electric potential gradient is generated by at least one of the following effects: (i) direct application of an electric potential across the solid electrolyte; (ii) introduction of interfaces of different electrode potentials between the solid electrolyte and conductive solids; (iii) introduction of an interface between the solid electrolyte and a conductive solid embodying atoms of lower ionization energy than at least one of the atoms forming the ions of the dissolved salt in solid electrolyte; (iv) application of external load and environmental effects which, either directly or when interacting with defects developed in the article during manufacturing and use, generate stress and temperature gradients which, in turn, produce or magnify the potential gradients between the interfaces with solid electrolyte. The mechanisms through which the electric potential gradient generated by different stimuli bring about changes in article performance involve migration of ions and their electrodeposition within the solid electrolyte and at interfaces.
摘要:
A method of joining two articles using slender nanomaterials is described. Randomly oriented nanomaterial mats or aligned nanomaterial arrays are introduced at the interface between the two articles followed by their energization via at least one of microwave irradiation and heating. The nanomaterial-to-nanomaterial and nanomaterial-to-surface contacts are enhanced by at least one of fusion, embedment and chemical reaction phenomena upon energization. The fusion, embedment and chemical reaction phenomena enhance at least one of the mechanical, electrical, thermal, durability and functional attributes of these contact points, which translate into improved properties of the joined article. The enhanced contact points enable effective use of the distinct qualities of nanomaterials towards development of joints which offer unique balances of strength, ductility, toughness, transport qualities, thermal stability, weathering resistance and other characteristics.
摘要:
A structurally efficient rod-stiffened panel incorporating pretressing benefits is provided, the prestress provided by pultruded rod which is already in the system. The pultruded rods being retained in either tension or compression stresses apply prestressing via interfacial behavior. The new system improves the efficiency of structural composites by tailoring the stress system within structure to fully utilize the structural potential of various components, and to avoid premature local failures within composite structures. A method for producing a prestressed rod stiffened composite structure is also provided.
摘要:
Concrete materials are impregnated with liquids which harden within concrete pores and microcracks, and develop a sharp contrast with the body of concrete in microscopic images. The impregnation process involves vacuum application to remove air from concrete pores and microcracks, followed by the introduction of liquids under pressure. The sharp contrast between the impregnated (and hardened) liquid and the body of concrete facilitates distinction of pores and microcracks in microscopic images for the purpose of automated image analysis.
摘要:
A non-shrink grout including Portland cement, sand and an additive which is a polymer incorporating at least one of a calcium compound and aluminum metal so as to be reactive with the cement. The grout when fresh expands during curing by gas formation and by hydration and expands when hardened. The grout is useful in construction.