Evaluation of electromagnetic shielding effectiveness of multi-axial fabrics and their reinforced PES composites

The usage of electrical and electronic equipments has been increasing in daily life, which has a potential hazardous impact on humans and other living organisms. In this paper, multi-axial fabrics containing steel yarns and carbon filaments, and their polyester (PES) resin-reinforced composites have been prepared for electromagnetic shielding applications. The electromagnetic shielding effectiveness (EMSE) of these structures was determined by using coaxial transmission line measurement technique. There were eight different multi-axial fabrics constructed. It was observed that the amount and the orientation of carbon and stainless steel yarns influenced the EMSE performances of multi-axial fabrics and their reinforced PES composites. The structures containing both carbon filaments and stainless steel yarns exhibited better EMSE than the ones including only one type of conductive yarns or filaments. Also, the EMSE performance of multi-axial fabrics was found better than their reinforced composites. The best EMSE results were obtained for the fabric, including two layers of yarns (steel and carbon) on top of each other in the centre with the angle of 45 and ?45°.     

Some virulence properties and characterization of motile Aeromonas species from milk and white cheese

Three hundred and thirty-eight samples of milk and milk products in Ankara were screened for the presence of motile Aeromonas species. The overall frequency of aeromonads in these samples was 27%. As expected, raw milk samples were more contaminated with aeromonads than were other products. Sixty-five (49.2%) of the 132 bulk raw milk samples were contaminated with aeromonads. In 35 of these samples, populations of aeromonads from 1.5 × 10² to 3.0 × 10³ cfu/mL were counted in ampicillin dextrin agar (ADA). Ten (40%) of the 25 raw milk samples sold in the street were contaminated with aeromonads. In eight of these samples, 1.2 × 10²−3.0 × 10³ cfu/mL were counted. Five (16%) of the 31 pasteurized milk and 12 (8%) of the 150 white cheese samples were contaminated with Aeromonas spp., but no countable aeromonads population was noted in ADA. The incidence of A. hydrophila, A. sobria and A. caviae in all samples was found to be 90.2%, 4.3% and 5.4%, respectively. The majority of the strains identified as A. hydrophila and A. sobria were able to produce haemolysin, protease and DNase, while strains identified as A. caviae were only positive for DNase. All isolated Aeromonas species ( A. hydrophila, A. sobria and A. caviae ) were positive for uptake of Congo red dye. Nevertheless, only strains identified as A. hydrophila and A. sobria showed a high rate of positive results when tested for the production of the Voges–Proskauer reaction and lysine decarboxylase. The results of this work show that motile Aeromonas spp., especially A. hydrophila , are frequently found in these samples. As these products are usually commonly consumed in Ankara, they can pose a risk especially for children, the elderly and immunocompromised individuals.     

A finite element model for independent wire rope core with double helical geometry subjected to axial loads

Due to the complex geometry of wires within a wire rope, it is difficult to model and analyse independent wire rope core accurately (IWRC). In this paper, a more realistic three-dimensional modelling approach and finite element analysis of wire ropes are explained. Single helical geometry is enough to model simple straight strand while IWRC has a more complex geometry by inclusion of double helical wires in outer strands. Taking the advantage of the double helical wires, three-dimensional IWRCs modelling is applied for both right regular lay and lang lay IWRCs. Wire-by-wire based results are gathered by using the proposed modelling and analysis method under various loading conditions. Illustrative examples are given for those show the accuracy and the robustness of the present FE analysis scheme with considering frictional properties and contact interactions between wires. FE analysis results are compared with the analytical and available test results and show reasonable agreement with a simpler and more practical approach.     

SHELF LIFE AND BIOCHEMICAL COMPOSITION OF BONITO FISH (Sarda sarda, BLOCH, 1758) STORED AT 4C AND FISHING WITH DIFFERENT FISHING TOOLS

This study was carried out to determine the effects of harvesting method and refrigerated storage on biochemical composition of Atlantic Bonito. Samples were fish caught with a surround trammel net and a drift net in the Middle Black Sea region by fisherman and were brought to the laboratory. Quality control analyses for soluble solid, protein, fat and ashes were performed. On the 10th day after refrigerated storage (4C), pH, total volatile base nitrogen (TVB-N), trimethylamine (TMA-N) and thiobarbituric acid (TBA) values were found in the drift net. In the fresh fish samples caught by surround trammel net and drift net, fat, proteins, soluble solids and ash contents were calculated.

PRACTICAL APPLICATIONS

The results of the proximate content of Atlantic bonito caught with a trammel net and drift net showed that fat contents were 5.76; protein contents were 20.35; dry matter contents were about 30.5% and ash contents was 1–1.2%. After 10 days of storage at 4C, pH, TVB-N, TMA-N and TBA values were 6.17, 34.46 mg/100 g, 7.34 mg/100 g and 7.72 mg malonaldehyde/kg, respectively, in the surround trammel net, and 5.98, 40.60 mg/100 g, 8.02 mg/100 g and 8.03 mg malonaldehyde/kg in the drift net, respectively. Based on these results, there were significant differences between surround trammel net fishing and drift net fishing in terms of meat quality.     

Modification of the renneting process in Berridge substrate by transglutaminase

The influence of enzymatic cross‐linking on the rennet coagulation of Berridge substrate was investigated in the rennet gel samples prepared by three different methods using a microbial Tgase. Protein cross‐linking was carried out at each of three stages: before the addition of rennet, simultaneously with rennet and after the addition of rennet. The results showed that the cross‐linking of milk proteins before the addition of rennet inhibited the primary enzymatic phase of rennet coagulation. It was observed that enzymatic cross‐linking affected both the primary and the secondary phases of rennet coagulation. The most suitable application method was the addition of transglutaminase at the 5th minute after the addition of rennet.     

Synthesis and characterization of malonic acid-doped polyaniline

The conductive form of polyaniline was synthesized by the anodic and chemical oxidation of aniline in malonic acid medium. The conductivity of polyaniline doped with malonic acid changed from 1.62×10–6 to 2.5×10–5Scm–1 depending on the way it was synthesized. The polymer growth rate was observed to be very slow in malonic acid compared with H2SO4. Thermogravimetric data revealed that the maximum thermal reaction rate of PANI doped with malonic acid was at 200°C and 520°C compared with 290°C and 530°C of the polymer doped with H2SO4.     

The influence of transglutaminase treatment on functional properties of set yoghurt

The objective of this study was to investigate the effect of transglutaminase (Tgase) on the functional properties of set yoghurt, due to enzymatic cross-linking of the milk proteins. Yoghurt samples were prepared from three formulations: reconstituted skim milk, and whole milk containing two different solid-non-fat (SNF) content, with four enzyme treatments: Control (no enzyme) and three microbial Tgase treatments: Pre-incubated 90 min, Pre-incubated and inactivated after 90 min, Not pre-incubated. The modifications which were caused by Tgase were found to be more clear when Tgase was active in set type yoghurts. It was found that nonfat yoghurt sample with lower SNF content can be produced with improved textural properties using Tgase.     

A STUDY ON THE RELATION BETWEEN ANTHOCYANIN CONTENT AND PRODUCT QUALITY: SHALGAM AS A MODEL BEVERAGE

ABSTRACT

The anthocyanin content and the amount of lactic and acetic acids present in commercial shalgam samples randomly collected from domestic markets were determined both by high‐performance liquid chromatography (HPLC) and spectral measurements. Shalgam samples produced under laboratory conditions were termed as the control group (Group I). The commercial samples were divided into three groups based on their production date: samples stored for 6–9 months as Group II; samples stored for 9–12 months as Group III; and samples stored longer than 12 months as Group IV. The HPLC chromatograms indicated that black carrot was the only source of anthocyanin present in the samples. The acylated to nonacylated anthocyanin ratio increased significantly in Group IV samples, whereas there were no significant differences among the Groups II, III and control (P < 0.05). The % polymeric color negatively correlated to the total anthocyanin content was significantly higher in Group IV samples (P < 0.05). The presence of high acetic acid content might be an indication of added pickle juice to the shalgam samples. The variance of the level of lactic acid found in commercial samples shows up as a problem of incidental enrichment of the lactic acid bacteria.

PRACTICAL APPLICATIONS

Anthocyanin profiles of food materials are unique. Therefore, the anthocyanin profile in a commercial beverage can be used to determine whether there is an adulteration or not. The total anthocyanin content and the ratio of acylated to nonacylated anthocyanins, together with the degree of polymerization and browning index, serve as indicators of the time–temperature history of the product. Applying first‐order degradation kinetics to the anthocyanin under question the initial hypothetical amounts of the juice bearing that anthocyanin can be evaluated. In the specific beverage investigated, shalgam, the level of lactic acid refers to the amount of bulgur used for fermentation. The amount of acetic acid and its negative correlation with the total anthocyanin content can be used as an indicator of adulteration with pickle juice.