Effect of nylon fabric reinforcement on the mechanical performance of adhesive joints made between glass and GFRP

The use of reinforcements in adhesive joints makes the stress distribution more uniform, improving their mechanical performance and adhesion. The present paper aims to verify the effectiveness and efficiency of the insertion of nylon 6 fabric in the adhesive layer, to study their applicability and functionality in building components. The increase in stiffness achieved by applying nylon 6 fabric in the adhesive layer between glass and GFRP pultruded profiles and steel laminates applied to GFRP beams is investigated. Three different epoxy adhesives and one epoxy resin are used and compared. Three different types of tests are carried out in order to study the different properties of the reinforcement system: tensile tests on GFRP/GFRP single-lap adhesive joints, with and without nylon fabric reinforcement; tensile tests on double-lap adhesive joints between float glass and pultruded GFRP profiles reinforced with nylon fabric according to four configurations (in the middle plane of the adhesive layer, on the glass surfaces, on the GFRP surfaces, on both GFRP and glass configurations) to verify the influence of its position; three-point bending tests on long GFRP tubular profiles reinforced with steel plates and nylon fabric in different configurations, to study resistance to bending loads. The results from the experimental campaign show the effectiveness of the reinforcement system using nylon fabric 6. In general, both a reduction in ultimate strength and an increase in joint stiffness compared to unreinforced configurations are observed.

Application of AgNPs/rGO Modified Nylon Fabric in Strain Sensing

The graphene oxide slurry was printed on the pre-stretched and non-pre-stretched nylon fabric by screen printing, and immersed in silver ammonia solution of different concentrations, and then reduced to obtain silver nanoparticles/reduced graphene oxide (AgNPs/rGO) modified nylon fabric with excellent conductivity. The surface morphology of the fabric was observed, and the performances of the fabric sensor that was scraped with graphene oxide slurry between the pre-stretched and non-pre-stretched states were explored. The resistance responses of the nylon fabric finished with different concentrations of silver ammonia solution under different strains (1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%) were investigated. The results showed that the nylon strain sensor was more sensitive and stable when the graphene oxide slurry was scraped in the pre-stretched state, and while the silver ammonia solution concentration was 10 mg/mL, the nylon fabric had maximum sensitivity and lowest hysteresis performance.

Mordant-free dyeing of nylon fabric with mahogany (Swietenia mahagoni) seed pods: A cleaner approach of synthetic fabric coloration

The extraction and consequent application of natural colorants obtained from mahogany ( Swietenia mahagoni) seed pod powder is described here. The colored solution was extracted by facile boiling in an acidic medium. Fourier-transform infrared spectroscopy indicated that the mahogany seed pod extract contained lignocellulosic substances. The typical strong broad band for -OH stretching vibration appeared at around the 3400 cm−1 region in the spectra indicating the presence of alcoholic groups in the substance. The acidic boiling of the mahogany seed pod extract showed the color bearing character at λmax 400–480 nm in the visible range of the ultra-violet spectrum. Subsequently, commercial single jersey-knitted nylon fabric was dyed with the mahogany seed pod extract. The effects of temperature, pH, and time were investigated meticulously for the above dyeing. The optimum conditions for nylon fabric dyeing with the mahogany seed pod extract were selected as the temperature of 100°C, dyeing time of 60 min, and dyebath pH 4.5. The results were interpreted in terms of color strength and fastness properties. The color fastness to wash and perspiration of nylon fabric dyed with mahogany seed pod extract was found to be moderate to good in the grey scale rating 3–4 to 4 grade in the case of optimum dyeing condition whereas color fastness to light was observed to be poor in the blue wool scale rating 2 grade. It was observed that dyeing time, temperature, and pH had profound influences on the color strength of the dyed material. The color strength was increased with the increase of dyeing period and dyebath temperature. The acidic dye liquor produced the darker hues while the alkaline condition had no effect on color yielding. The fabric was dyed uniformly, confirming the evenness of dyeing which is very important for successful commercial dyeing.

Human identification from washed blood stains

Background Among the physical evidence, bloodstain is one of the most common biological pieces of evidence at the crime scene, especially in violent crimes. Bloodstains are frequently seen at the crime scene and can be easily detected due to their color and structure. Because blood and bloodstains can potentially be evidence of a crime, offenders often tend to clean or wash them to get rid of relevant evidence. Some researchers think that washed bloodstains cannot obtain enough quality DNA for DNA profiling. However, some studies have shown that bloodstains on a piece of fabric can be used for DNA profiling even after washing. This study, it is aimed to determine whether a sufficient amount of DNA can be obtained for DNA profiling used for forensic purposes from blood-stained nylon and cotton fabrics washed at different temperatures such as 40 °C, 60 °C and 90 °C. Results In this study, bloodstains were created on cotton and nylon fabrics in a representative crime scene. After washing with laundry detergent at 40 °C, 60 °C and 90 °C was performed, studies were conducted in order to make bloodstains visible and obtain DNA for genetic profiling. The result is that more DNA is lost due to easy exposure to external factors in the non-absorbent nylon fabric type compared to the absorbent cotton fabric. Moreover, the rates of obtaining DNA from bloodstains on different types of fabrics washed at several temperatures are shown in this study. Conclusions It was determined that while a sufficient amount of DNA for the forensic genetic profiling can be obtained from cotton and nylon fabrics washed at 40 and 60 °C, a sufficient amount could not be obtained from the ones washed at 90 °C. And that shows even if bloodstained fabrics are washed at 60 °C, the fabrics still can be considered as physical evidence of the crime and can be associated with the scene, perpetrator and victim triangle.

Optimization of Sodium Lignosulfonate Treatment on Nylon Fabric Using Box–Behnken Response Surface Design for UV Protection

Graphical Abstract