Nanoflower hydroxyapatite's effect on the properties of resin-based dental composite

To investigate the reinforcing effect of nanoflower-like hydroxyapatite (NFHA) in resin-based dental composites, we synthesized a novel NFHA using microwave irradiation (MW), hydrothermal treatment (HT), and sonochemical synthesis (SS). Silanized NFHA was then used as the reinforcing filler in dental resin composites. We characterized the structure and morphology of various HA nanostructures using x-ray diffraction, scanning electron microscope, and TEM. The mechanical performance of dental resin composites reinforced with silanized NFHA was measured using a universal testing machine. Spherical HA, synthesized through chemical precipitation (CP), served as the control group. One-way analysis of variance was employed for the statistical analysis of the acquired data. The results demonstrate that the nanoflower morphology significantly was improved mechanical and physical properties. After conducting trials, the NFHA synthesized using MW and HT showed a substantial enhancement in mechanical and physical properties compared to the other structures. Therefore, it can be concluded that NFHA can serve as a novel reinforcing HA filler, providing regenerative properties to resin composites with sufficient mechanical strength.     

Bond strength of polymer lightweight aggregate concrete

Bond strength, physical, and mechanical properties of lightweight PC were investigated with inclusion of pumice lightweight aggregate in maximum size of 12 mm. As binder material, epoxy resin‐based polymer was used with its hardener. The binder to aggregate ratio was 30% by weight. In addition, steel fibers were added to lightweight PC mixtures in ratio of 0, 0.5, and 1%. After lightweight PC mixture was prepared, it was poured in the molds with different type of steel‐bars in size of 100 × 100 × 100 mm³. The steel‐bars centered in the cubic molds, and they were in size of Ø12, Ø14, and Ø16. The specimens were cured at 60°C for 2 h. On the hardened polymer lightweight concrete (PLC), pull‐out test for bond strength and compressive strength tests were performed. Moreover, ultrasonic pulse velocity, water absorption by weight, specific porosity, and density experiments were carried out. The relation between physical and mechanical properties showed that PLCs become more durable when using ratio of steel fibers. POLYM. COMPOS., 34:2125–2132, 2013. © 2013 Society of Plastics Engineers     

Effects of structural parameters on compressibility and soiling properties of machine woven carpets

Compressibility performance of the machine woven carpet after a static or dynamic loading expresses the texture deformation tendency of the carpet. This study is an experimental attempt to investigate the effects of pile height and pile density on compressibility and soiling property by dynamic loading, prolonged heavy static loading, compression recovery and artificial soiling tests. In this study, a total of 12 carpet samples with three different pile heights and four different pile densities were tested. As a result of this study, it was seen that higher pile density provides a lower thickness loss and so a lower level of texture deformation. On the other hand, pile height has a preventing effect for texture deformation for static loading and compression recovery tests whereas there is no considerable effect on dynamic loading test. There is no considerable difference between the soiling properties of the samples.     

More about fibre friction and its measurements

Unfortunately, the classical empirical friction laws do not hold true for fibrous and viscoelastic materials comprising most of the textile fibres. In the second half of the twentieth century, fibre surfaces have been studied by many distinguished scientists who were able to complete numerous researches for the frictional characteristics of different types of fibres. Most of the researchers have aimed to develop a new test method and a test device that can be used to measure the frictional characteristics of fibres quickly, accurately and easily in their studies. Unfortunately, there is not a standard test method or a test device for the measurement of textile fibres' friction properties. For today's competitive marketing, the instrument for fibre testing must be very fast and accurate; otherwise, it will not be useful for commercial purposes. For example, hundreds of thousands of cotton bales should be tested within a very short period of time in terms of the length, colour and trash content of the cotton bales. Without having the data describing the properties of cotton fibres, cotton bales cannot be sold commercially in most of the countries. Therefore, it is an important factor that the fibre-testing instrument should be fast and accurate. Most of the properties of cotton fibres can be assessed by using a HVI fibre-testing instrument. In this review, the historical perspective of fibre friction studies has been demonstrated with the fibre friction measurement-testing devices.     

Deposition of nanoparticle multilayers to improve mechanical properties of denim fabrics

Al₂O₃ nanoparticles were used for fabrication of multilayer nanocomposite film deposition on cationic denim fabrics by electrostatic self-assembly to improve the mechanical properties. Denim fabrics were pre-treated with 2,3-epoxypropyltrimethylammonium chloride (EP3MAC) by a pad-batch method for cationic surface charge. Attenuated Total Reflectance Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy and Scanning Electron Microscopy were used to verify the presence of deposit nanolayers. CIELab analysis was performed on the fabrics before and after the treatment with Al₂O₃ nanoparticles by the layer-by-layer (LbL) deposition method. After aging processes, the effect of LbL deposition method on the tensile strength properties of denim fabrics was also investigated.     

Adaptive control of let-off system in weaving

In this study, semi-positive let-off system in a conventional weaving loom was controlled using conventional, PID (Proportional Integral Derivative) and fuzzy logic based control systems. To do this, servomotor was installed into the let-off unit of the loom using PID controller, additionally fuzzy logic based let-off control was realised. Experimentally obtained warp tension values for each control methods were compared. According to the results, maximal tension values for the conventional, PID and fuzzy logic controlled systems were found to be 53, 45 and 35 cN, respectively. As a result, it is determined that the least warp tension interval and mean warp tension value are in let-off system controlled by fuzzy logic.     

Relation between fabric porosity and vacuum extraction efficiency: Energy issues

Vacuum extraction is a technique that removes the unbound water from the fabrics by the help of air flow through the fabrics at high velocities. Air flow through textile fabrics is mainly affected by the fabric structure such as tightness, porosity and air permeability. This paper outlines the effects of the fabric structure on the vacuum drying efficiency. Thirty woven fabrics with different porosities were dried by vacuum extraction method, and it was found that the lower the porosity or the lower the air permeability, the higher the water removal effects and energy requirement.     

Diversity and Stability of Yeast Species During the Fermentation of Tarhana

Tarhana is a traditional cereal-based fermented food produced with a mixture of yoghurt and flour. The main microbiota in the fermentation of tarhana is yeast, together with lactic acid bacteria. In this study, the yeast microbiota of home-made tarhana (HMT) and plant-type tarhana (PTT) dough samples was evaluated and compared during fermentation. Culture-dependent LSU and ITS-5.8S rDNA sequence analysis of yeast isolates collected during the tarhana dough fermentation clarified 45 selected isolates representing different clusters. These yeast isolates displayed high homologywith species Pichia kudriavzevii (11), Candida glabrata (11), Candida humilis (10), Saccharomyces cerevisiae (7), Kluyveromyces marxianus (4), Kazachstania servazzi (1), and Kazachstania unispora (1). Additionally, both culture-dependent and PCR-Denaturated Gradient Gel Electrophoresis (PCR-DGGE) analyses showed that S. cerevisiae, P. kudriavzevii and K. marxianus were abundant in the fermentation of HMT dough samples whereas P. kudriavzevii, C. humilis, and C. glabrata dominated the PTT dough samples. It was concluded that tarhana fermentation was accomplished with the presence of a wide variety of yeast species that mainly included P. kudriavzevii in both HMT and PTT dough samples.     

Changes in Chemical and Microbial Qualities of Dried Apricots Containing Sulphur Dioxide at Different Levels During Storage

Effects of different sulphur dioxide (SO₂) concentrations (188, 452, 791, 1,034, 1,236, 2,899 and 3,864 mg SO₂ kg^?1) and storage temperatures (5, 10, 20 and 30 °C) on the physical, chemical and microbial qualities of sulphited-dried apricots (SDAs) were evaluated. Analysis of kinetic data suggested first-order models for losses of moisture and SO₂ and formation of brown colour. Strong correlations were found between SO₂ concentrations and moisture loss constants (r?=??0.943), and brown colour values (r?=?0.949). β-carotene contents in SDA samples ranged from 26.6 to 36.2 mg 100 g^?1 dry weight, depending on SO₂ content of dried apricots. The SO₂ concentration over 791 mg per kg of dried apricots effectively protected carotenoids in dried apricots during drying. While storage times had significant effect on β-carotene contents, storage temperatures did not have such effects. The number of total mesophilic aerobic bacteria in all SDA samples ranged from 8.20?×?10¹ to 1.84?×?10² CFU g^?1. The number of total psychrophilic aerobic bacteria, lactic acid bacteria, yeast and mould, xerophilic mould, Staphylococcus spp. and total Enterobacteriaceae were below the detection limits (<4 CFU g^?1) in samples containing SO₂ even at the lowest level (188 mg SO₂ kg^–1) throughout the storage. Regardless of SO₂ concentration in dried apricots, low storage temperatures (below 20 °C) should be preferred to prevent the characteristic golden yellow colours of dried apricots.     

Single-Laboratory Validation for the Determination of Aflatoxin B1, B2, G1, and G2 in Foods Based on Immunoaffinity Column and Liquid Chromatography with Postcolumn Derivatization and Fluorescence Detection

This study presents a method validation procedure for the determination of aflatoxin B₁, B₂, G₁, and G₂ in hazelnut, hazelnut paste, walnut, peanut, pistachio, corn, and wheat. The method consisting of clean-up with immunoaffinity column, high performance liquid chromatography with postcolumn derivatization and fluorescence detection was validated in accordance with Commission Regulation 2004/882/EC. The selectivity, linearity, decision limit, detection capability, detection and quantification limits, precision, recovery, ruggedness, and measurement uncertainty of the method were determined. The limit of detection and limit of quantification values (μg/kg) were: aflatoxin B₁, 0.02, 0.07; aflatoxin B₂, 0.01, 0.02; aflatoxin G₁, 0.02, 0.07; and aflatoxin G₂, 0.01, 0.03. The relative standard deviation values for the repeatability and within-laboratory reproducibility were below 4 and 5 %, respectively. The recovery values of the spiked samples ranged from 80 to 105 %. These results complied with minimum performance criteria established by regulation 2006/401/EC. Therefore, the procedure can be implemented for the routine analysis of aflatoxins in the studied matrices.