Papers by Keyword: Biomimetic

Abstract: With the increasing projects on surveillance and monitoring purposes over the years, the requirement of visual equipment especially in autonomous mobile robot (AMR) has improved. By implementing Computerized Fluid Dynamic (CFD) method, Coanda-effect was introduced to get better flow characteristic (radial and tangential pressure - velocity profiles) on surface particle cleaning in AMR application. To establish this condition, a novel design of particle removal based on human lacrimal system was reconstructed and gradually examined to obtain optimized particle cleaning which carried out in FLUENT and iSIGHT. Throughout the history of mankind, nature has become a source of inspiration towards technical and engineering design. A biomimetic approach was utilized as main concept in providing design process with incorporating both form aspects and functional principles. As design process progressed, the bionic innovation can serve as a prominent role in the development of engineering design. Simultaneous practice - recognition - practice is repeated, in order to make things more consistent with the simulated production needs. Under these circumstances, the growth and structure of surface disturbances by a coaxial airflow in accordance with pressure distribution and shear stresses were numerically investigated. Furthermore, an optimization method for achieving optimal particle cleaning was formulated based on independent variables with the objectives to maximize pressure flow and drag force coefficient while minimizing the dynamic turbulence flow. The influence of pressure distribution, nozzles angle of attack and particle matters have also been explored. Result shows that this design structure qualitatively represents characteristic of the optimum surface cleaning performance in terms of particle drag force and energy efficiency.

Abstract: The influence of employing three different solution temperatures (23, 37 and 50 °C), three soaking times (2, 4 and 6 h) and two solution refreshing methods (Refreshed or Non-refreshed) in rapid biomimetic coating process on phase composition, functional groups, coating content and microstructure of the resulted coating was studied. Increasing soaking times and temperature increased the coating content in all cases regardless of the use of refreshed or non-refreshed accelerated calcium phosphate solution. The use of non-refreshed solution resulted in the lower rate of coating than that of refreshed solution at all coating temperatures. However, all coatings similarly comprised octacalcium phosphate and hydroxyapatite as main phases and the microstructure consisted of sharp and interconnected plate-like crystals vertically grown on the surface of titanium. However, two types of crystal structure were produced. Low solution temperature resulted in isolated spheroids while uniform and distributed crystal structure was produced by using high solution temperature. This could be related to the difference in nucleation and precipitation rate formed in rapid biomimetic coating process as a result of the interplay between temperature and ionic strength of the solutions.

Abstract: Bio-inspired nanogels were prepared by ionically crosslinking sodium tripolyphosphate (TPP) and biomimetic phosphorylcholine-chitosan derivative (PCCs) which was synthesized from chitosan and cell membrane-mimicking phosphorylcholine. The physcochemical properties of PCCs/TPP nanogels were investigated by dynamic laser scattering and transmission electron microscopy, as well as their hemocompatibility were tested. Bovine serum albumin was used as a model protein to study protein adsorption, loading and releasing property of these nanogels in vitro. The results indicated that biomimetic PCCs/TPP nanogels can not only restrain the non-specific protein adsorption, improve the hemocompatibility, but also have good loading and releasing protein efficacy, which will be a promising nanocarrier for protein drug delivery.

Abstract: Hydroxyapatite (HA) is a well known bioactive material in the application of coated orthopaedic and dental implants. Recently, biomimetic technique has been explored to deposit a stable carbonated HA on a metal surface, mimicking the properties of natural bone. The aim of this study is to surface characterize the biomimetic hydroxyapatite (HA) and metallized silver (Ag) functionalized on a polydopamine film grafted titanium alloy (Ti6Al4V). The Ti6Al4V disks were grafted with the polydopamine film to provide catechol/quinone groups for chemical binding process. The grafted surfaces were metallized with Ag in silver nitrate solution. The metallized surfaces were then grafted with the second layer of polydopamine film and further biomineralized with HA in 1.5 simulated body fluid (SBF) solution for 3 and 7 days. The chemical compositions and chemical functionalities of those functionalized surfaces were characterized by XPS, FTIR and EDS. The morphologies of the surfaces were viewed under SEM. Finally, the wettability properties of the surfaces were investigated by water contact angle analysis. The XPS results showed that the polydopamine films were grafted on the Ti6Al4V surfaces. The polydopamine films became the chemical binding medium for functionalization of Ag and HA as the existence of both elements were clarified in XPS and EDS data. The appearance of HA functional groups (phosphate groups) were only noticed on FTIR spectrum when the biomimetic process was performed at 7 days. The formation of biomimetic HA has produced a hydrophilic surface with an appearance of hemispherical lath-like HA structure which is crucial for osseointegration and bone growth stability.

Abstract: In this study, the influence of employing three different sodium hydroxide (NaOH) pretreatment concentration (1, 3 and 5M) and two cleaning methods (Ultrasonic or Rinse) used in rapid biomimetic coating process on phase composition, function groups, thickness, amount and microstructure of the resulted coating was carried out. Regardless of process parameters, x-ray diffraction and Fourier transform infrared spectroscopy revealed that the all coating mainly comprised octacalcium phosphate and hydroxyapatite as main phases while the microstructure similarly consisted of sharp and interconnected plate-like calcium phosphate (CaP) crystals vertically grown on the surface of titanium. However, the change in sodium hydroxide concentration in pretreatment step and cleaning method influenced the weight change after pretreatment, coating continuity and uniformity, but not the weight change after coating. This could be related to amount of the amorphous alkali gel layer formed during pretreatment step which influenced the rate of coating formation in rapid biomimetic coating process.

Abstract: Central nerve system degeneration is a crucial problem for many patients. To use an in situ hydrogel formation is an attractive method to treat that problem. An in situ hydrogel was developed for central nerve system regeneration. An acid soluble collagen (ASC) and pepsin soluble collagen (PSC) from the shark skin of the brownbanded bamboo shark (Chiloscyllium punctatum) were used to produce hybridized hydrogels by the biomimetic approach. Collagen was mixed with methylcellulose and used 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) as a crosslinker. The hydrogels had various ratios of collagen:methylcellulose: 100:0, 70:30, 50:50, 30:70, and 0:100. Structural, molecular, and morphological organization were characterized and observed by differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), and scanning electron microscopy (SEM). The DSC results showed that the peak of denatured collagen fibril shifted higher in a 30:70 ratio of collagen:methylcellulose in both ASC and PSC. The FT-IR results indicated that the structure of hydrogels from both ASC and PSC were organized into complex structures. The SEM results demonstrated that the collagen fibril networks were formed in both ASC and PSC hydrogels. The results indicated that the samples containing collagen promise to be an in situ hydrogel for central nerve regeneration.

Abstract: It has been well-known that butterfly wings possess interesting optic properties. Recently, dendritic micro-nanostructure has been found in the wing scales of butterfly Trogonoptera brookiana, which shows excellent light-trapping effect, especially for the visible light. When light enters such a dendritic micro-nanostructure, it will be trapped and eventually absorbed by multiple reflections to generate heat. It is desirable to prepare a biomimetic structure resembling the micro-nanostructure of the butterfly wing scale, which may lead to a new material that can potentially improve the light utilization rate of solar thermal heater and other similar applications. However, a convenient method to make such a structure in large scale is still lacking. Herein, an easy and handy approach has been developed to prepare biomimetic dendritic structure. The starting material is negative photoresist, a chemical reagent which is widely used in photography. A simple device that can adjust the intensity and interval of ultraviolet illumination has been designed and set up. A periodic structure has been achieved via photo-curing with ultraviolet light and the ratio of illumination time has been optimized.

Abstract: A facile biomimetic method was developed to enhance the interfacial interaction in organic-inorganic hybrid materials. By mimicking mussel adhesive proteins, a monolayer of polydopamine (PD) was constructed on surface of Al (OH)₃ particles through a controllable coating pathway. The modified Al (OH)₃ (PD-Al (OH)₃) was incorporated into an epoxy resin. It is found that the strong interfacial interactions brought by the polydopamine benefits the effective interfacial stress transfer, leading to greatly improved flexural properties of the organic-inorganic hybrid resin.

Abstract: With reference to a certain type of flying drones with imitation airfoil design a seagull flat wings and on the basis of its wing tip winglet in this paper. Through to the numerical simulation of two wings, it is concluded that the bionic wing aerodynamic performance is superior to the conventional airfoil wing, after adding wing tip winglet bionic wings effectively reduced the downwash velocity, reduce the induced drag, makes the wing aerodynamic performance is improved. Provide theoretical reference for the design of the uav wing

Abstract: The two-degree-of-freedom (two-dof) shock isolation system has been presented based on the woodpecker’s head structure. The effect of the system parameters on the performance of the shock isolation system has been studied by using transient responses and shock response spectrum. The results show that appropriate parameters can effectively reduce the maximum acceleration and displacement of the woodpecker’s brain. The discussion provides a new insight to the shock isolation mechanism of woodpecker’s head, and would be useful for the design of shock isolation.