Mechanical and thermal properties of talc and calcium carbonate filled polypropylene hybrid composites

The main aim of this work was to study and compare the mechanical and thermal properties of hybrid polypropylene (PP) composites and single‐filler PP composites. With two main types of mineral fillers—calcium carbonate (CaCO₃) and talc—PP composites of different filler weight ratios (talc/CaCO₃) were compounded with a twin‐screw extruder and then injection‐molded into dumbbell specimens with an injection‐molding machine. Tensile, flexural, and impact tests were performed to determine and compare the mechanical properties of the hybrid and single‐filler PP composites. A synergistic hybridization effect was successfully achieved; the flexural strength and impact strength were highest among the hybrids when the PP/talc/CaCO₃ weight ratio was 70:15:15. The nucleating ability of the fillers and its effects on the mechanical properties were also studied with differential scanning calorimetry. Because of the influence of talc as the main nucleating agent, the hybrid fillers showed significant improvements in terms of the nucleating ability, and this contributed to the increase in or retention of the mechanical properties of the hybrid composites. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 91: 3327–3336, 2004     

Scattered Data Interpolation Using Cubic Trigonometric Bézier Triangular Patch

This paper discusses scattered data interpolation using cubic trigonometric Bézier triangular patches with continuity everywhere. We derive the condition on each adjacent triangle. On each triangular patch, we employ convex combination method between three local schemes. The final interpolant with the rational corrected scheme is suitable for regular and irregular scattered data sets. We tested the proposed scheme with 36,65, and 100 data points for some well-known test functions. The scheme is also applied to interpolate the data for the electric potential. We compared the performance between our proposed method and existing scattered data interpolation schemes such as Powell–Sabin (PS) and Clough–Tocher (CT) by measuring the maximum error, root mean square error (RMSE) and coefficient of determination (). From the results obtained, our proposed method is competent with cubic Bézier, cubic Ball, PS and CT triangles splitting schemes to interpolate scattered data surface. This is very significant since PS and CT requires that each triangle be splitting into several micro triangles.     

Surfactant Synthesis via Lipase Esterification of Methyl α-d-Glucopyranoside with Selected Aliphatic Carboxylic Acids

Lipase‐catalyzed esterification and properties of synthesized carbohydrate esters were investigated. Methyl α‐d ‐glucopyranoside was the acyl group acceptor and different carbon atom chain lengths of aliphatic carboxylic acids (C12, C14 and C16) as the acyl group donors were applied in the esterification. Physico‐chemical studies on the synthesized carbohydrate esters were carried out. It was found that melting point for the methyl 6‐O‐hexadecanoyl‐α‐d ‐glucopyranoside was the highest consecutively followed by methyl 6‐O‐tetradecanoyl‐α‐d ‐glucopyranoside and methyl 6‐O‐dodecanoyl‐α‐d ‐glucopyranoside. Liquid crystal properties of the synthesized carbohydrate ester synthesized were evaluated via optical polarized microscopy. It was found that the liquid crystal textures for mono‐substituted carbohydrate esters were of the smectic phase. In a quaternary system (carbohydrate ester/n‐butanol/n‐hexadecane/water), a maximum 34 % of water (by mass) was contained in the monophasic region of methyl 6‐O‐tetradecanoyl‐α‐d ‐glucopyranoside and a maximum of 52 % water (by mass) was contained in a monophasic methyl 6‐O‐dodecanoyl‐α‐d ‐glucopyranoside. For methyl‐6‐O‐dodecanoyl‐α‐d ‐glucopyranoside, its concentration at aggregation was 5.2 × 10^?4 mM, with minimum air/water surface tension of 26 mN m^?1. The Gibbs energy of micellization was calculated at ?50 kJ mol^?1. The maximum adsorption density of methyl 6‐O‐dodecanoyl‐α‐d ‐glucopyranoside was determined at 4 × 10^?6 mol m^?2 while its minimum area per surfactant molecule at the air/water surface was 47 Ų.     

Study on effect of filler loading on the flow and swelling behaviors of polypropylene‐kaolin composites using single‐screw extruder

Melt flow and extrudate swelling behavior of polypropylene‐kaolin (PP‐Kaolin) composites were investigated using a single‐screw extruder. Kaolin was mixed with polypropylene (PP) using a heated two‐roll mill at 185°C and the filler loading were varied from 5 to 30 wt %. Subsequently, flow behavior of the compounded formulations were evaluated through Melt Flow Index (MFI) measurement at various temperatures ranging from 190 to 230°C. The extrudate swelling ratio was also measured by using an image analysis instrument and software. It was proven that the MFI decreased with increasing loading of kaolin for test temperatures of 190 and 200°C. However, for temperatures exceeding 200°C, the MFI value rose slightly at 5 wt % of kaolin content then seemed to reduce as more kaolin was added. This is also detected in rheological measurement where the apparent visosity, η_app, appear to be lowered at 5 wt % loading of kaolin. Further increase in kaolin loading resulted in increasing value of the composites η_app. The swelling ratio decrease with increasing filler loading for composites below 20 wt %. However, at 30 wt % of kaolin content, the extrudate swelling ratio increased and noticeable blistered surface texture was observed on the extrudate surface. Furthermore, at this level of filler loading, shrinkage occurence due to the existence thermal gradient between the surface and the inner core of the extrudate caused void formation in the middle section of the extrudate. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Deployment of a 3D tag tracking method utilising RFID

Recent trend shows that one of the crucial problems faced while using radio frequency to track the objects is the inconsistency of the signal strength reception, which can be mainly due to the environmental factors and the blockage, which always have the most impact on the tracking accuracy. Besides, three dimensions are more relevant to a warehouse scanning. Therefore, this study proposes a highly accurate and new three-dimensional (3D) radio frequency identification-based indoor tracking system with the consideration of different attenuation factors and obstacles. The obtained results show that the proposed system yields high-quality performance with an average error as low as 0.27?m (without obstacles and attenuation effects). The obtained results also show that the proposed tracking technique can achieve relatively lower errors (0.4 and 0.36?m, respectively) even in the presence of the highest attenuation effect, e?=?3.3 or when the environment is largely affected by 50% of the obstacles. Furthermore, the superiority of the proposed 3D tracking system has been proved by comparing with other existing approaches. The 3D tracking system proposed in this study can be applicable to a warehouse scanning.     

Immunomodulation and Regenerative Capacity of MSCs for Long-COVID

The rapid mutation of the SARS-CoV-2 virus is now a major concern with no effective drugs and treatments. The severity of the disease is linked to the induction of a cytokine storm that promotes extensive inflammation in the lung, leading to many acute lung injuries, pulmonary edema, and eventually death. Mesenchymal stem cells (MSCs) might prove to be a treatment option as they have immunomodulation and regenerative properties. Clinical trials utilizing MSCs in treating acute lung injury (ALI) or acute respiratory distress syndrome (ARDS) have provided a basis in treating post-COVID-19 patients. In this review, we discussed the effects of MSCs as an immunomodulator to reduce the severity and death in patients with COVID-19, including the usage of MSCs as an alternative regenerative therapy in post-COVID-19 patients. This review also includes the current clinical trials in utilizing MSCs and their potential future utilization for long-COVID treatments.     

Application of differential scanning calorimetry (DSC), HPLC and pNMR for interpretation primary crystallisation caused by combined low and high melting TAGs

The main goal of the present work was to assess the mechanism of crystallisation, more precisely the dominant component responsible for primary crystal formations and fat agglomerations. Therefore, DSC results exhibited significant effect on temperature transition; peak sharpness and enthalpy at palm stearin (PS) levels more than 40 wt.%. HPLC data demonstrated slight reduction in the content of POO/OPO at PS levels less than 40 wt.%, while the excessive addition of PS more than 40 wt.% increased significantly PPO/POP content. The pNMR results showed significant drop in SFC for blends containing PS less than 40 wt.%, resulting in low SFC less than 15% at body temperature (37 °C). Moreover, the values of viscosity (η) and shear stress (τ) at PS levels over 40 wt.% expressed excellent internal friction of the admixtures. All the data reported indicate that PPO/POP was the major component of primary nucleus developed. In part, the levels of PS should be less than 40 wt.%, if these blends are designed to be used for margarine production.     

Crystallisation regime of w/o emulsion [e.g. multipurpose margarine] models during storage

Multipurpose margarine (MPM) or water-in-oil (w/o) emulsion systems were prepared using palm oil (PO)/palm stearin (PS) blends as continuous phases and stabilized by monoacylglycerol (90% monoester) as emulsifier. Experimental analyses of three out of six models of MPM showed that MPM1, MPM2 and MPM3 had low workability force and weaker network structure. As results the solid fat content (SFC) at 28 °C, consistency, storage modulus (G′) and softness were 25%, 15.5 × 10² kPa, 2.62 × 10² kPa and 30 mm ease of cone penetration, respectively. Furthermore, examination microscopy of the images concerning MPM1, MPM2 and MPM3 revealed the presence of symmetrical crystals after 60 days of storage, whereas the MPM4, MPM5 and MPM6 models exhibited asymmetrical crystals during same incubation time. These results indicated that the diminution of PS versus PO contents induced the retardation of phase transition from less stable beta-prime (β′) crystals to the more stable beta (β) crystals during storage.     

Interference management issues for the future 5G network: a review

Telecommunication Systems - The future wireless Fifth Generation (5G) communication network required a higher bandwidth in order to achieve greater data rate. It will be largely characterized by...