Acoustic Attenuation Performance of Two-Pass Perforated Hybrid Mufflers with Mean Flow

The one-dimensional (1-D) analytical approach is developed to predict and analyze the acoustic attenuation performance of two-pass perforated hybrid mufflers in the presence of mean flow. The expressions of complex acoustic wavenumber and impedance of long fiber glass wool are presented by using the impedance tube measurement and curve fitting. The 1-D approaches as well as the fitting expressions are validated by comparing the predicted and measured transmission loss of two-pass perforated hybrid mufflers with a different Mach number. Results illustrate that the 1-D predictions agree well with measurements below the plane wave cut-off frequency and deviate in higher frequency range. The influences of geometric parameters including the lengths of extended tubes, perforations on the right bulkhead and the outlet tube, and mean flow on the acoustic attenuation behavior of the hybrid mufflers are examined.

Experimental analysis of shear connection effect composite beams with concrete

The subject of this research is the analysis of shear connection effect on the fiber glass reinforced composite beams. The research contains the detailed analysis of materials like concrete and fiber glass reinforced composite. The shear connection has been tested by the experiment of push out test run in the Centre of research and innovation in construction of Technical University of Košice. The shear connection has been tested on two types of connectors used on composite beams. The main idea of this research is find out whether it is possible to use the alternative material, which should substitute the steel. The aim of research is to design a type of connector for fiber reinforced composite materials or another composite materials developping in the world of material engineering. The part od research is devoted to the FEM analysis.

Influence of out-of-plane fiber waviness and different environmental conditionings on mechanical and morphological characteristics of fiber glass/epoxy laminates

The use of structural polymeric composites constitutes an interesting option in the area of wind turbine blade manufacturing. Nevertheless, thick composite components may present out-of-plane waviness in their fibers, compromising the service life of the wind blades. In this context, the present study aims to study the influence of out-of-plane waviness in the fibers with different degrees of severity as well as to verify the effect of fiber glass/epoxy resin composites immersion in distilled water and saline solution in their tensile strength (σmax), modulus of elasticity (E), and deformation at break (єrup), analyzing the reinforcement/matrix interface changes. The results showed that the increase in severity promoted, in general, a statistically significant deterioration in σmax of the samples exposed to the same environmental conditioning. The conditioning led to a decrease in E and an increase in єrup, attributed to the deterioration of the interface and the plasticization of the polymeric matrix, respectively, as evidenced by fractographic analysis. The effect of severity on the єrup and σmax properties was only noticed in laminates exposed to environmental conditioning, due to water sorption favoring the deterioration of the matrix/reinforcement interface, intensifying the deleterious effect of out-of-plane waviness of fibers.

Optimization of Sisal Fiber, Glass Fiber and Alumina- Based Hybrid Composite for Flexural Strength Using Taguchi Technique

In the current study, flexural strength of combination of natural and synthetic fiber with particle filled hybrid composites have been studied. The flexural strength of the hybrid composite mainly depends on the proportion of the sisal fiber weight, glass fiber weight and alumina weight. Taguchi technique has been applied to find the optimized parameters of the developed hybrid composites. Results were obtained for the L9 orthogonal combination from experimentation. The results were analysed with the help of Signal/Noise (S/N) Ratio, Main effect plot and Analysis of variance (ANOVA) using Mini Tab 19. Regression equation are developed for all three reinforcements separately. From the current study it was observed that the flexural strength of the hybrid composite mainly depends on the sisal fiber precent that the other two reinforcements. Based on the experimental observations the maximum ultimate flexural strength was found to be 145.97 MPa for optimised input parameters as 20% of sisal fiber, 20% of glass fiber and 2% of alumina. Keywords: Taguchi technique, ANOVA, Flexural strength, Sisal fiber, Glass Fiber, Alumina

Physical, Biochemical, Cytological, Bacteriological Screening of Carpal hygroma Fluid vis-a-vis Surgical Management of Carpal hygroma in Cattle and Buffaloes- A report of 15 Cases

Fifteen animals affected with unilateral 9 and bilateral 6 carpal hygroma were presented with the history of swelling on the anterior aspect of the carpus since 3-18 month. Hygroma fluid samples from all the cases were aseptically collected for physical, biochemical, cytological and bacteriological investigations. The colour of hygroma fluid was pale yellow with slight deposits. Glucose, chloride and total protein levels were 43±4.08 mmol/dL, 107±6.50 mmol/dL and 3.20 g/dL, respectively. Cytological examination revealed cell count of 150 cells/µL, 20% neutrophils and 80% lymphocytes. Moreover, mild (+) cellular degeneration changes were also seen. The hygroma fluid samples from all animals were screened for brucellosis. Two cows were found positive for Brucella in tube agglutination test with antibody titres of 160 and 320 IU, respectively. Whereas, the hygroma fluid samples from other animals showed no growth on culture. Surgical excision of carpal hygroma in all cases was done under xylazine sedation (@ 0.02mg/kg body wt) and intravenous regional anaesthesia (IVRA). In brucella infected cows (n=2), hygroma sacs were excised en mass. Skin sutures were applied and the limb was put in fiber-glass cast for 10 days. In bilateral cases, the hygroma of one limb was treated at first instant followed by counter limb after 15 days. In all cases, the wound healing occurred by first intention without any complication. It was concluded that brucella organism may be present in hygroma fluid and due precaution are required while collecting fluid samples. The presence of hygroma may be considered as evidence of brucellosis in the herd. The owners should be advised not to breed such animals in future.

Optimization for Tensile Strength of Sisal Fiber, Glass Fiber and Alumina- Based Hybrid Composite using Taguchi Technique

Natural fibers composite play an important role in making eco-friendly products. The present investigation has been made to find tensile strength of hybrid composites fabricated using optimal composition of sisal fiber, glass fiber and alumina. Multi-response optimization has been carried out. The compositions of reinforcements namely sisal fiber, glass fiber and alumina in hybrid composite were prepared by Hand-layup technique. Sisal fiber of 20 Wt.%, 30 Wt.% and 40 Wt.% are chopped into 10mm length, Glass fiber of 20 Wt.%, 30 Wt.% and 40 Wt.% are 10mm length and alumina particles of 2Wt.%, 3 Wt.% and 4 Wt.% are compositions of reinforcement were chosen according to orthogonal array as Taguchi technique(L9). The results have been verified through confirmatory experiments. Experimentations were carried out with the different composition based on L9 process parameters. Based on the experimental observations the maximum ultimate tensile strength was found to be 37.87 MPa for optimised input parameters as 20% of sisal fiber, 30% of glass fiber and 3% of alumina.

Properties and Structure of UV Light Cured CIPP Composites

One of the methods of curing (Cured-In-Place Pipe) CIPP pipes is the curing using ultraviolet (UV) light. The main difference from common CIPP types is in the structure of the liner material. In terms of material, it is a woven fiber glass fabric which is saturated with vinyl ester or polyester resin. In general, these pipes are more resistant to chemicals and achieve higher values of flexural properties. The paper focuses on the investigation of the short-term mechanical properties using three-point bending test and structure of UV cured CIPP liners. The computed tomography (CT) was used for the analysis of CIPP internal structure and composition.