UV curable lens production using molecular weight controlled PEEK based acrylic oligomer (Ac-PEEK)

We produced UV curable lenses with properties blocking short wave UV light. In the UV-curable formulations, we used an oligomer (Ac-PEEK) with another urethan oligomer (Mw = 2000). Radically active, molecular weight controlled Ac-PEEK was obtained by reacting 2-hydroxyl ethyl methacrylate with molecular- weight- controlled and isocyanate terminated PEEK (Mn = 4500). We characterized all synthesized monomer, oligomer and optical materials with UV/Vis spectrophotometer with interferogram, elemental analyser, mass spectrophotometer, proton nuclear magnetic resonance, Fourier transform infrared spectroscopy, thermal gravimetric analyzer, differential scanning calorimeter, scanning electron microscopy and gas chromatography. Results suggested that newly synthesized oligomer with the structure of PEEK absorbs short wave UV-light. Ageing tests [ISO 11979-5, Ophthalmic implants—intraocular lenses (IOL)—Part 5: Biocompatibility] performed on the IOL materials were successful. High contact angle of the obtained lenses suggests that all lenses were hydrophobic and SEM results revealed that lenses are morphologically homogeneous. Based on all positive properties just mentioned, we safely conclude that the lenses produced in this study are very promising for IOL production.     

Application of antimicrobial ice for extending shelf life of fish

In this study, we investigated whether wild-thyme (Thymus serpyllum) hydrosol had a preserving effect against spoilage of freshwater fish. Sensorial characteristics, chemical freshness indicator contents, and microbial counts (total aerobes, psychrotrophics, Enterobacteriaceae, fecal coliform bacteria, Aeromonas spp., and Pseudomonas spp.) of whole ungutted and gutted Transcaucasian barb (Capoeta capoeta capoeta Guldenstaedt, 1772) stored on ice produced from wild-thyme hydrosol and tap water at 4 degrees C for 20 days were compared. The results did not reveal any significant (P > 0.05) differences in the microbial counts, sensorial characteristics, pH, and total volatile basic nitrogen values between gutted and ungutted groups. Sensory evaluation and microbiological and chemical analyses indicated that the storage of the fish on ice produced from wild-thyme hydrosol had a significant increase in shelf life by at least 15 to 20 days.     

Multi-scale directional-filtering-based method for follicular lymphoma grading

Follicular lymphoma (FL) is a group of malignancies of lymphocyte origin that arise from lymph nodes, spleen, and bone marrow in the lymphatic system. It is the second most common non-Hodgkins lymphoma. Characteristic of FL is the presence of follicle center B cells consisting of centrocytes and centroblasts. Typically, FL images are graded by an expert manually counting the centroblasts in an image. This is time consuming. In this paper, we present a novel multi-scale directional filtering scheme and utilize it to classify FL images into different grades. Instead of counting the centroblasts individually, we classify the texture formed by centroblasts. We apply our multi-scale directional filtering scheme in two scales and along eight orientations, and use the mean and the standard deviation of each filter output as feature parameters. For classification, we use support vector machines with the radial basis function kernel. We map the features into two dimensions using linear discriminant analysis prior to classification. Experimental results are presented.     

Notes on chlorinated polyethylene: Its preparation,some mechanical and thermal properties

Low density polyethylene was chlorinated via a mixed solution-suspension technique at three different temperatures. The products obtained at different conditions had properties ranging from hard brittle to tough elastomeric consistencies. Static mechanical, chemical, and thermal characterization of the products were made and the possibility of two different crystal structures is pointed out, one of which is consumed preferentially during chlorination.     

A new approach for measuring RMS value and phase angle of fundamental harmonic based on Wavelet Packet Transform

Traditional ways of calculating/measuring harmonics in power systems have been based on Fourier Transform and algorithms, such as Fast Fourier Transform and Goertzel that implements it. In this study, a novel approach based on Wavelet Packet Transform is presented to measure Root-Mean-Square (RMS) value and phase angle of the fundamental harmonic. To this end, analytical expressions were derived and using a Graphical User Interface (GUI) designed and experimental works the validity of analytical expressions was demonstrated.     

Evaluating the fabric performance and antibacterial properties of 3-D piezoelectric spacer fabric

The increasing need of on-demand power for enabling portable low-power devices and sensors has necessitated work in novel energy harvesting materials and devices. In a recent work, we demonstrated the production and suitability of three-dimensional (3-D) spacer all fibre piezoelectric textiles for converting mechanical energy into electrical energy for wearable and technical applications. The current work investigates the textile performance properties of these 3-D piezoelectric fabrics including porosity, air permeability, water vapour transmission and bursting strength. Furthermore, as these textiles are intended for wearable applications, we have assessed their wear abrasion and consequently provide surface resistance measurements which can affect the lifetime and efficiency of charge collection in the piezoelectric textile structures. The results show that the novel smart fabric with a measured porosity of 68% had good air (1855 l/m²/s) and water vapour permeability (1.34 g/m²/day) values, good wear abrasion resistance over 60,000 rotations applied by a load of 12 kPa and bursting strength higher than 2400 kPa. Moreover, the antibacterial activity of 3-D piezoelectric fabrics revealed that owing to the use of Ag/PA66 yarns, the textiles exhibit excellent antibacterial activity against not only Gram-negative bacteria E. coli but they are also capable of killing antibiotic methicillin-resistant bacteria S. aureus.     

Graphene and carbon black filled conductive nanocomposite films for heating element applications

Graphene has ultra-high electrical and thermal conductivity, which makes graphene as the most encouraging fillers for thermally conductive composites. Graphene and/or carbon black filled conductive polymer composite (CPC) films used as heating element are smarter than the traditional heating elements due to less environmental pollution, ease of application on many surfaces and possess the merits of lightweight. In this study, we investigated mainly the production, characterization and industrial application of graphene/carbon black reinforced styrene acrylic copolymer emulsion matrix composite films deposited on polyvinyl chloride for flexible heating element. After that, the films were dried at room temperature for 24 h in air. Structural and surface properties of the CPC films were characterized by X-ray diffraction and scanning electron microscopy. Temperature, time and voltage relation of the produced composite films were investigated. Heating and electrical properties of the CPC films were determined by using a thermal camera and 4-point probe measurement system, respectively. The electrical resistivity of the CPC films decreases from ~?10⁸ to 10¹ Ω cm with increasing the filler content or using a combination of two fillers. Graphene and carbon black filled conductive polymer composites to be considered as candidates for flexible heating element applications exhibited good electrical and heating properties thanks to synergistic effect of fillers.