Multiaxial fatigue characterization of self-reinforced polylactic acid-calcium phosphate composite

The majority of failures of mechanical components are caused by fatigue. Unlike many conventional engineering components, implants in the body are subjected to complex multidirectional loading patterns, thus fatigue not only occurs under axial, fully or partly reversed loading, but also under torsional loading. The fatigue behaviours of self-reinforced poly lactide composite (PLA) of unidirectional PLA fibres in PLA matrix containing tricalcium phosphates (TCP), (PLA-PLA-TCP) produced via pre-pregging technique has been investigated. Quasi-static test results indicated that PLA-PLA-TCP is stronger in tension than in compression and torsion and is significantly influence by moulding temperature. Uniaxial fatigue testing at 37° C in saline solution established S-N (Wöhler) curves for both axial and torsional loading for two moulding temperatures (140°C and 150°C). Compression loading showed significant effect on the axial fatigue behaviour. Biaxial fatigue results showed that the addition of torsion to axial loading significantly reduced the fatigue life. Out-of-phase loading was less detrimental to the fatigue life than in-phase. Fatigue development was evaluated by reduction in secant modulus and increase in energy absorbed. The threshold number of cycles at which damage starts to accumulate in the composite was found to be load ratio and direction dependent. The effects of the degradation process in saline solution on the fatigue behaviour of the composite were also studied at 25% of the ultimate tensile and shear stresses. The specimens were immersed for 8, 12, 16 and 20 weeks periods before testing. The results indicated that even though immersion in saline solution reduced the static and cyclic properties of the composite, it still had good strength retention and comparable to the cortical bone at the end of 20 weeks of degradation period. Microscopy examination on the fracture surface indicated that in uniaxial tension-compression fatigue, the failure was dominated by compression and failed via microbuckling mechanism. Biaxial fatigue failure was dominated by shear mechanisms with evidence of interfacial failure and fatigue striations

Effect Of pH Condition During Hydrothermal Synthesis On The Properties Of Hydroxyapatite From Eggshell Waste

Hydroxyapatite (HA) powders were synthesized using eggshell waste through hydrothermal method to develop bioceramics materials for medical applications. The effects of the pH conditions during the synthesis on the phase behaviour, crystallite size, crystallinity and morphology of as-synthesized ceramic powders were evaluated. The XRD patterns showed that HA was the only main phase present in the as-synthesized powder after being calcined at 400°C. However, EDX measurement detected the presence of Mg as trace element which originated from the eggshell as starting materials. The crystallite size and crystallinity of the HA powders were increased when the powders were synthesized in acidic condition as compared to basic condition. FESEM images showed that HA powder with nano-sized rods and spherical morphologies were obtained from the powders that were synthesized at pH 5, while the powder particles synthesized at the basic condition at pH 9 produced elongated rodshape particles. The PSD results showed that the synthesized HA was in agglomerated form which was also confirmed by FESEM images

Taxation, e-commerce and determination of permanent establishment / Zaleha Othman and Mustafa Mohd Hanefah

E-commerce provides a new way of conducting commercial transactions in today’s global market. E-commerce has made the world a one big marketplace. However, e-commerce also poses challenges to the existing tax rules in determining permanent establishment of businesses. Permanent establishment has been used as the criteria to determine whether a country has taxing rights on the business profits of a non-resident taxpayer. Most tax experts view the current concept of permanent establishment as insufficient to cope with e-commerce, as it is seen to be more suitable for traditional business transactions rather than internet trading. This paper investigates the application of current tax laws in Malaysia on the determination of permanent establishment in an e-commerce environment. Implications of existing policy to establish the source of income in e-commerce are also explored. Interviews were conducted to solicit opinions of tax officers and tax professionals in Malaysia. The respondents agree that the criteria used to determine permanent establishment should be applicable to both types of transactions: conventional and e-commerce. However, the respondents perceived that additional criteria should be included to determine permanent establishment in e-commerce transactions and some modifications to its definition are necessary to suit the modern form of trading over the internet

Utilisation Of Recycled Thermoplastics Sourced From Rejected-Unused Disposable Diapers As Polymer Blends

The blending of two or more thermoplastics could produce polymer blends, which are preferable compared to developing a new type of plastic. This paper presents the study on the utilisation of recycled thermoplastic polymers which are recovered from rejected-unused disposable diapers. The aim of study is to characterise the effect of manufacturing temperature on the tensile and morphological properties of recycled plastic blend. Besides that, the polymer blend sourced from virgin materials was also prepared to compare the properties. The recycled and virgin materials were blended by using an internal mixer with fixed parameters. Later, the blended materials were crushed and moulded using hot compression moulding with temperature variations of 180 °C, 190 °C and 200 °C. The tensile tests were conducted in accordance with the ASTM D638 using a universal testing machine, followed by scanning electron morphological analysis. The results showed that as temperature increases, tensile strength decreases and tensile strain increases for both recycle and virgin blends. Tensile strength and strain for the recycled blend were also lower than the virgin blend at all temperatures, due to low miscibility in the recycled blend compared to the virgin one. The low miscibility caused more macrophase separation and resulted in poor adhesion between the polymer components. Also, the increase of temperature caused the tensile modulus to be reduced for the recycled blend. Meanwhile for the virgin blend, the modulus reduced at 190 °C but increased suddenly at temperature of 200 °C

Determination of permanent establishment in e-commerce: An exploratory study

Permanent establishment has been used as a principle or threshold to determine whether a country has taxing rights on the business profits of a non-resident taxpayer.That threshold, however, has raised many questions in the context of e-commerce. Many countries are now concerned of how to determine permanent establishment in an e-commerce environment. Some view that the existing rule is insufficient to cope with e-commerce. This is because the existing tax rules were not designed in the era of e-commerce.Tax authorities are also concerned about the tax revenue loss, as there are no specific tax laws relating to permanent establishment in e-commerce. This study was conducted to solicit the perceptions of tax offices and tax practitioners on the criteria used to tax business profits in an e-commerce environment.This paper discusses how permanent establishment is determined in the conventional and e-commerce environments.The findings indicate that the existing tax threshold concerning permanent establishment is applicable in taxing e-commerce business profit, however, further amendments and changes should be incorporated to cater for e-commerce environment.The subjects also perceived that additional criteria should be included in the existing tax laws on permanent establishment to ensure tax treatment on e-commerce do not leave room for tax loss

E-commerce implication: Potential tax problems and challenges in Malaysia

The shift in business models to incorporate e-commerce by great expectations of future growth, have naturally attracted the attention of both private sector tax professionals and government tax authorities.With the use of internet as a medium in conducting business transactions, people are now taking the opportunities to expand business has triggered problems to the government in taxing the transactions since there is no physical presence exist, and therefore, creates problems for tax collection.Thus, this study draws attention to the importance of taxing e-commerce transactions and investigates tax problems and challenges posed by e-commerce businesses in Malaysia.A survey approach was conducted in gathering the necessary data.The results show that tax administration is ranked as the highest tax problem posed by e-commerce business in Malaysia and there is no significant difference in the opinion of the subjects in relation to taxing of either tangible or intangible product.In addition, overall findings also reveal that occupation, business nature, and experiences do not influence the subjects' opinions towards e-commerce tax liability in regards to tax problem and legality of claiming taxes in various jurisdictions, and residence-based system appears to be the best solution to solve the problem of internet trading

On The Use Of Nano Fibrillated Kenaf Cellulose Fiber As Reinforcement In Polylactic Acid Biocomposites

In this study, nano fibrillated kenaf cellulose (NFKC) derived from kenaf fiber after varying chemico-mechanical treatments were introduced into poly lactic acid (PLA) as reinforcements to improve the mechanical and morphological properties of the biocomposites. The new strategy was aiming to realize the synergistic effects of chemical treatment and mechanical fibrillation process parameters (blending speed and time) for yielding nanofibers and its reinforcement effects on the properties of biocomposites. The yield percentage of the NFKC was determined using centrifugal method and the NFKC fibers with PLA pellet were hot pressed to form NFKC-PLA composites. The distribution and dispersion morphologies of NFKC in NFKC-PLA composites were observed by using optical microscope (OM) and scanning electron microscope (SEM). The reinforcing effect on the mechanical properties of NFKC-PLA composite was investigated by tensile strength test. Average length and diameter of fibrillated fibers were decreased with the concurrent increase of blending speed and time. The maximum increase in tensile strength of 59.32% and elongation of 100% were observed for NFKC-PLA composite with NFKC yielded at a blending speed and time of 15000 rpm and 15 minutes as compared to pure PLA. The tensile properties indicated that the strength and modulus were improved with increased nanofiber contents

Credit evaluation by the small-medium sized enterprises: Maqasid Shariah approach

This paper aims to examine the practice of credit evaluation by Islamic banking in evaluating financing proposals from the SMEs in Malaysia. Also, how the approach of Maqasid Shariah which encompasses of religion, life, lineage, intellect and property influencing the application of credit evaluation from the SMEs. This paper measures credit evaluation on Islamic banks based on review of literature; the inputs are extracted from the existing relevant studies on the subject matter. The findings reveal that that the elements of Maqasid Shariah are not being considered meticulously for credit evaluation processes. The Maqasid Shariah approach in credit evaluation could bring significant values for SMEs in securing financing. This novel study significantly focuses on how the SMEs in Malaysia process the credit evaluation based on the CAMPARI model while adapting the concept of Maqasid Shariah. As this conceptual paper focuses on the previous research and existing available data, the paper is a stepping-stone that enables the researchers to obtain an inclusive and complete perspective and solutions for both Islamic banking system and their customers

Thermal And Mechanical Behaviour Of Recycled Polypropylene/Polyethylene Blends Of Rejected-Unused Disposable Diapers

This paper presents the characterization of recycled plastic that derived from the rejected-unused disposable diapers containing polypropylene (PP) and polyethylene (PE), noted as r-PP/PE. The blends were tested for thermal, mechanical and morphological properties. Tensile test showed that the r-PP/PE is lower in strength and strain but higher for modulus in comparison to the v-PP/PE by 56%, 55%, and 2% respectively. For the flexural properties, the r-PP/PE also has lower in strength, strain, and modulus as 67%, 13%, and 77% respectively. Lower absorbed energy and impact strength was observed in r-PP/PE, 36% and 24% respectively compared to v-PP/PE. Thermal analysis revealed that the degree of crystallinity of recycled PP and PE was 19% and 20% lower than the virgin possibly due to thermal degradation during the process. Morphological examination revealed the present of impurity, phase separations and inhomogeneity were found in the r-PP/PE as compared to v-PP/PE that might contribute to their lower strength

Effects Of Heating Rates And SBE Loading On Sintered Properties Of Spent Bleach Earth/Recycled Glass Composite

The purpose of this study is to investigate the influence of different heating rates on the properties of glass ceramic composite (GCC) at different spent bleach earth (SBE) loadings. GCC was prepared using SBE and recycled soda lime silicate (SLS) glass. The particle size of SLS glass was approximately <45μm. The GCC was formed by uniaxial dry pressing at weight fractions of SBE loading of 40 wt. %, 45 wt. %, and 55 wt. %. The GCC was then sintered at different heating rates of 2 ºC/min, 4 ˚C/min, 6 ºC/min and 8 ˚C/min at 700 ºC of sintering temperature. The GCC specimens were analysed in terms of their physical properties, while crystalline phase and microstructure were characterized using X-Ray diffraction and scanning electron microscope (SEM), respectively. The results from X-Ray diffraction pattern showed that quartz and wollastonite phases were formed with no major changes on the phases as the heating rate increased. The results indicate that the variation of heating with 2 ºC/min interval does not give a remarkable result of physical properties on GCC. High loading of SBE sintered at 2 ºC/min of heating rate produced low water absorption, density and porosity. SEM analysis showed that the physical properties and crystalline phases were correlated to the SBE loading and changes in the heating rate. The study concluded with the prospect of continuing the work of optimisation on schedule heat treatment at sintering temperature regimes