Papers by Keyword: CPC

Abstract: This work focuses on studying the possibility of 3D printing of composite materials composed by cork and a polymer matrix (CPC). Initially the cork was mixed with two types of polymers (HDPE and PP) in different proportions and later processed using extrusion and injection. The composites were tested to study the physical, chemical and mechanical properties. The material was then tested on a large-scale 3D printer to study its feasibility and the ability to produce new products through 3D printing. Attention was focused on the use of pure cork, varying the concentration of cork and coupling agent in thermoplastic matrix composites of PP and HDPE. It was demonstrated that the increase of 5wt.% of coupling agent in the two types of polymers significantly improved the mechanical properties and adhesion between the phases but the increase in cork concentration decreased mechanical properties and crystallinity. The CPCs with PP showed to have better mechanical properties, better aesthetic and internal structural quality, and easier processability than those with HDPE matrix. Nevertheless, the HDPE CPCs showed a high degree of crystallization. Concerning 3D printing, with the filament obtained was demonstrated the possibility of making new products based on natural cork fibers, showing promising results, although additional research is still needed to optimize the process.

Abstract: We designed a lithographic system, which consists of an ultraviolet LED array as the source, a Compound Parabolic Collector (CPC) as the light collection and collimator, a double fly’s eye len and a convergent lens as light energy Homogenization unit. The second fly’s lens as a field lens is placed to the back focal plane of the first one to improve the light energy uniformity as the light rays output from the CPC are not strictly parallel. The simulation based on optical software indicated that the lithographic system is good at collecting and distributing uniformly light energy. It is a better solution as ultraviolet LED is good at space, price, Environmental Protection compared with Ultraviolet (UV) laser and high pressure mercury lamp.

Abstract: In order to enhance the signal intensity of VLC-LED receiver, this paper describes a receiver condenser which is designed based on optimized CPC (compound parabolic concentrator) by using a truncated method, for achieving the aim of boosting receiver’s ability of gathering light and enhancing signal intensity. The Monte Carlo-ray tracing simulation results shows that in the VLC-LED system, the optimized CPC condenser has those advantages, such as higher concentration ratio, larger concentrate light deviation angle.

Abstract: A CPC for LFR system was designed and its mathematical model was established. Maximum acceptance angle and truncation ratio was optimized to 45° and 0.75, which two elements mainly affect the optical performance of CPC. Moreover, the non-uniform of incident angle can considerably improve the CPC concentration ratio. Results show that the CPC with 475.49mm opening width could achieve a high concentrate ratio reach up to 80.15%. This conclusion was further verified by an experimental measurement results.

Abstract: As electro-hydraulic control system of strip steel CPC has some special characteristics, such as strong nonlinear, changes in structural parameters, serious time-delay and the very difficultly of establishing accurate mathematical model, the integral-separate PID improved predictive control algorithm was proposed on the basis of the new mathematical model. Firstly, the integral-separate PID algorithm was used to make system asymptotic stability and reduce overshoot of system. Secondly, the predictive control algorithm was proposed, error feedback correction model was improved, and predictive control signal was optimized with rolling method. Finally, the system was simulated and analyzed in noise and pulse disturbance. The simulation results show that this algorithm can effectively improved abilities of anti-noise and anti-load disturbance, increases robustness and tracking capability of strip steel CPC system; furthermore, it can improved speed of system response and decrease time-delay and overshoot of system. Therefore, this algorithm can well meet the need of electro-hydraulic control system for strip steel CPC system.

Abstract: From human bones to animal bones, from stainless steel to plastic, researchers have tried numerous types of materials to apply in the bone replacement for human-beings. But deal to their limitation on fatigue, stability, mechanical strength and many other properties, almost all those past materials were superseded by bioceramics today, which perform not only those advantages possessed by the old materials, but also hydrophilic, biocompatibility, thus ensured them a promising future in the region of bone tissue engineering. This mainly talk about and give examples of some application progresses of bioceramics in the region of bone tissue engineering, and the visions of their future utilization.

Abstract: In the environment of CPC, CRM has already evolved from a kind of marketing tool which mainly faces to the sale management into a manufacturing principle which covers the whole production line from the product creativity to the terminal consumer. Based on the Internet, the Pan-CRM concerns and satisfies customer's changeful and characteristic needs, integrates the related personnel of product life cycle to a common body under the premise maximizing common values. So the core manufacturer gets free gathering innovation, and the special requests of consumers are realized as far as possible.

Abstract: Calcium phosphate cement (CPC) is a self-hardening material for bone repairing. ZnO whisker is a new type reinforced materials lately, which is acerose single crystal fiber. In this study, ZnO whisker was added into the CPC with different ratios, and each specimen kept at 37 oC in 100% humidity for 24 hrs. The phase and microstructure of the calcium phosphate pastes were investigated using X-ray diffraction and scanning electron microscopy, respectively. It has been found that ZnO whisker could supply nucleating center, TTCP and DCPA could be much easier to form HA around the ZnO whisker. The adding amount of ZnO whisker is a key factor that determines the mechanical properties.

Abstract: Unsintering macroporous calcium phosphate scaffolds with macropore sizes of 200∼400μm and hydroxyapatite nanofiber of in-situ growth were prepared by coating porous polyurethane templates with α-tricalcium phosphate bone cement (CPC) slurry, and their subsequent hydrolysis to calcium deficient hydroxyapatite (HAp) during the self-setting processes are presented. The effects of Sr2+ (SrNO3) on the nucleation, growth of the hydroxyapatite nanofiber and phase constitution were studied. The results show that the main component of the coating is HA after hydrolysis for 72h and the Sr2+ added could depress the growth of block or sheet HA crystal and promote the nanowhisker growth. This new processing technique can be used to improve the bioactivity of porous polymer template while maintaining its macroporous structure.

Abstract: Demineralized bone matrix (DBM)-calcium phosphate cement (CPC) composites were subjected to cellular test of osteogenic potentials and implantation in animal model. The expression of osteogenic marker gene from mouse preosteoblast cell line MC3T3-E1 adhered to the DBM-CPC composite was much higher than plain CPC. In addition, the DBM-CPC composite implanted nude mice revealed osteoinduction between the implanted composite and adjacent tissues, whereas the plain CPC induced osteoconduction.