Effect of Fiber-matrix Interface Decohesion on the Behavior of Thermoset and Thermoplastic Composites Reinforced with Natural Fibers: A Comparative Study

In this article, a comparative study was carried out on two types of thermosetting and thermoplastic matrices to study the effect of the fiber-matrix interface damage on the behavior of thermosetting and thermoplastic composites reinforced by the same natural alfa and wood fibers. The genetic modeling was based on the probabilistic formalism of Weibull. The results have been compared with those obtained by the nonlinear acoustic technique, the two results found to coincide perfectly. The numerical simulation also shows a good concordance with the real behavior of the materials studied, and shows that thermosetting composites are the most resistant to applied thermal stress by 21% compared to thermoplastic composites. Statistical analysis demonstrates that the correlation coefficient values found are very close to 1 (0.964 and 0.973), these values are very satisfactory, and confirm that the results obtained by the genetic model and the nonlinear acoustic technique are in very good agreement with the statistical analysis data. The experimental work presented by Antoine Le Duigou et al. and the work of Bodros et al. have shown that the use of natural fibers greatly improves the mechanical properties of composite materials

Numerical Study of the Effect of Elastomer and Cement of Stress Absorbers on the Reduction of Stresses in Tibia and Tibial Bone Analysed by Finite Element Method

Metal alloys have been the materials of choice since the start of orthopaedic surgery. Orthopedic materials must fulfill the mechanical, biological and physical necessities of their proposed utilization. Knee joint is the most complex joint in human body, which gets the discriminating loads in different moving conditions. Accordingly, the material utilized for knee implant is assumed the exceptionally essential part for long survival of knee prosthesis. The materials that are utilized as biomaterials incorporate polymers, metals, ceramics and composites. Out of those materials, cobalt-chromium alloys, titanium alloys, stainless steel and ultra high molecular weight polyethylene are the most usually utilized biomaterials for knee implants. The objective of this paper is to prepare three models of prosthesis knee joint from available literature and study on the distribution of von Mises stresses and strains in different components of knee prosthesis. It is known that the total displacement between the intact model and the artificial model of knee, 3D modeling software Solidworks 2016 is used for 3D modeling of knee prosthesis, and that finite element analysis software ANSYS 16.2 was used for numerical estimation of von Mises stresses and strains. We found in this study that the maximum von Mises stresses and strains at the level of the tibial and tibial bone decreased, that is to say, the cement and the elastomer played a very important role in the absorption of the stresses and their minimization. On the other hand, the four knee prostheses (model Ⅰ (Ti6Al4V), model Ⅱ (CoCrMo), model Ⅲ (316L SS), model Ⅳ (ZrO2)) implanted by elastomer contributed significantly to the reduction of stresses in the patella bone compared to the intact model. In general, both models of the knee prosthesis and those reinforced by a stress reduction system (cement or elastomer) gave a lower stress level in the tibia and tibial bone of a normal person compared to a healthy model. The results obtained provide a theoretical basis for choosing an appropriate surgical model

A Study on Factors of Affecting Customer Satisfaction-The Case of Coffee Chain Shop in Taiwan

近年來臺灣咖啡市場蓬勃發展且消費量迅速攀升，但也導致龐大使用飲料杯對於環境造成相當大的負擔。考量永續經營與民眾綠色消費意識的崛起，業者如何擬訂綠色行銷策略，在降低環境衝擊外，同時提升企業形象已是重要的議題。 本研究透過498份調查問卷，鎖定網路市調品牌知名度前五名的連鎖咖啡店，透過敘述統計分析、信效度分析、因素分析、相關分析、迴歸分析及路徑分析等方法，了解影響消費者滿意度之關鍵因素，同時進一步暸解消費者涉入、企業形象、綠色行銷認知及顧客滿意度各變項間的關聯性，提供連鎖咖啡店業者在擬定綠色行銷策略時，能確切回應顧客的需求，以建立良好的形象並提升目標顧客的滿意度。 本研究主要結論如下: 1.消費者涉入與企業形象有正向顯著關係； 2.企業形象與顧客滿意度有正向顯著關係； 3.消費者涉入與顧客滿意度有正向顯著關係； 4.綠色行銷認知與企業形象有正向顯著關係； 5.企業形象對於消費者涉入與顧客滿意度之間具有中介效果。Taiwan''s coffee consumption has experienced booming growth in recent years. Due to the low recycle rate of disposable beverage cups, it has caused a severely burden to our environment. To reserve the living surrounding for the next generaion, public sector implements the relevant environmental protection measures and considers to raise the public awareness of green consumption. This study focuses on the brand awareness of the top five coffee shop chains. 498 valid questionnaires were collected and analyzed to understand what the key factors to affect the consumer’s satisfaction on coffee and in developing of green marketing strategy. Descriptive statistical analysis, reliability and validity analysis, factor analysis, correlation analysis, regression analysis and path analysis were used to evlauate four diemensions, include consumer involvement, corporate image, green marketing awareness and customer satisfaction between the various variables, are considered in research. Major conclusions are presented as follow: 1.Consumer involvement has a significant positive relationship with business image; 2.Business image and customer satisfaction significantly positive related to each other; 3.Consumer involvement positively related to customer satisfaction; 4.Green marketing awareness and corporate image has a significant positive relationship; and 5. Business image plays a mediator between consumer involvement and customer satisfaction.摘要 i Abstract ii 目錄 iii 表目錄 v 圖目錄 vi 第一章 緒論 1 第一節 研究背景與動機 1 第二節 研究目的 3 第三節 研究範圍及限制 3 第四節 研究流程 4 第二章 文獻回顧 5 第一節 消費者涉入 5 第二節 企業形象 9 第三節 綠色行銷認知 12 第四節 顧客滿意度 16 第三章 研究設計 19 第一節 研究架構 19 第二節 研究假說 20 第三節 研究變項的操作型定義及衡量 23 第四節 問卷設計與抽樣 27 第五節 研究方法與資料搜集 28 第四章 實證結果分析 33 第一節 敘述性統計 33 第二節 信效度分析 36 第三節 相關分析 45 第四節 迴歸分析 46 第五節 路徑分析 50 第五章 結論與建議 53 第一節 研究結論 53 第二節 管理意涵 55 參考文獻 57 附錄 6

Date and doum palm natural fibers as renewable resource for improving interface damage of cement composites materials

Abstract Background Various recent studies have investigated the use of traditional fibers (metallic or synthetic) as reinforcement in mortar. In recent times, there has been growing interest in using natural fibers as reinforcement in cement composites. This study was conducted to assess the impact of date palm, doum palm, and sisal fibers on the mechanical properties of cement composites. Genetic modeling was chosen to find the shear damage at the fiber-matrix interface of the three cement composites using genetic crossing operator, which allows us to calculate the damage at the interface using two damages of the matrix and the fibers, respectively. Results Our objective is to examine and evaluate the interface damage of date palm/mortar, doum palm/mortar and sisal/mortar under different mechanical tensile stresses ranging from 25 to 37 MPa with fiber volume fraction from 1 to 5%. It was found that the interface damage of date palm/mortar and doum palm/mortar cement composites was minimal compared to that of sisal/mortar. However, several researchers found that an increase in fiber volume fraction leads to decrease in mechanical properties and density in cement composites what we confirmed in this study that interface damage increases when the volume fraction increases. Conclusions The results are in line with the findings of a recent experimental study on the use of other plant fibers. Their results showed that incorporating ramie fibers resulted in a 27% increase in compressive strength, whereas the use of synthetic fibers resulted in 4% decrease in tensile strength in compression. It is recommended the use of doum and date palm natural fibers in the composition of mortars with a fiber volume fraction of 1 to 5% in order to reduce and avoid interface damage and limit the negative impact of synthetic fibers on the environment