Evaluation of Modal Damping of Graphite/ Epoxy Laminated Composites

The damping of an engineering structure is important in many aspects of noise and vibration control, fatigue endurance and so on, since it controls the amplitude of resonant vibration esponse. Damping in fiber-reinforced composite aterials is highly tailorable with respect to constituent roperties, fiber volume fractions and ply orientation angles.To this end an experimental analysis of the damping of unidirectional graphite reinforced epoxy composites was carried out. Damping characteristics of laminates are analysed experimentally using impulse technique. Composite laminate were made using the traditional hand-lay -up process. Experimental dynamic tests were carried out using specimens with different fiber orientations and three different boundary conditions and different thickness

Evaluation of Modal Damping in FRP based Laminated Composites through Modal Testing

The main source of damping in laminated composite materials arises from the inelastic nature of the matrix and the relative slipping at the fiber/matrix interfaces. Damping in laminated composite materials is usually a function of many parameters including the volume fraction of the fibers, fiber diameter and fiber orientation relative to the axis of loading.Also the magnitude and frequency of the applied load and many environmental factors should be mentioned. Since the complex phenomenon of damping is difficult to incorporate into the structural dynamic analysis of laminated plates, a modal damping approximation is employed here. Various methods have been presented to obtain the modal damping of a laminated composite.In this paper, classical modal testing of bi-woven laminates under various boundary conditions and analysis of the damping is carried out. Laminates made of Glass and Graphite fibers with epoxy resin as matrix is used in modal testing. Traditional “Strike Method” is adopted which consists of impulse hammer and accelerometer with 4-channel FFT analyzer to obtain the response of the specimen under test. Results obtained from both laminates are compared and it is observed that damping properties of graphite is more dominant than glass laminates

Web Proxy Cache Replacement Policies Using Decision Tree (DT) Machine Learning Technique for Enhanced Performance of Web Proxy

Web cache is a mechanism for the temporary storage (caching) of web documents, such as HTML pages and images, to reduce bandwidth usage, server load, and perceived lag. A web cache stores the copies of documents passing through it and any subsequent requests may be satisfied from the cache if certain conditions are met. In this paper, Decision Tree (DT ) a machine learning technique has been used to increase the performance of traditional Web proxy caching policies such as SIZE, and Hybrid. Decision Tree (DT) is used and integrated with traditional Web proxy caching techniques to form better caching approaches known as DT - SIZE and DT - Hybrid. The proposed approaches are evaluated by trace - driven simulation and compared with traditional Web proxy caching techniques. Experimental results have revealed that the proposed DT - SIZE and DT - Hybrid significantly increased Pure Hit - Ratio, Byte Hit - Ratio and reduced the latency when compared with SIZE and Hybrid

Development and validation of a Yoga module for Primary dysmenorrhoea

Menstrual pain without organic pathology is considered to be primary dysmenorrhoea. Dysmenorrhoea refers to the occurrence of painful menstrual cramps of uterine origin. It is a common gynaecological condition with considerable morbidity affecting majority of the adolescent girls, yet which is under diagnosed and under treated. Yoga can be considered as a simple and safe management tool for Primary Dysmenorrhoea. Studies have reported the beneficial role of Yoga in alleviating the symptoms of Primary dysmenorrhoea; however, a validated Yoga module for Primary dysmenorrhoea is unavailable. This study developed and validated an integrated Yoga module (IYM) for Primary dysmenorrhoea. Methods: The IYM was prepared after a thorough review of classical Yoga texts and previous findings. Twenty experienced Yoga experts, who fulfilled the inclusion criteria, were selected validating the content of the IYM. A total of 38 practices were included in the IYM, and each practice was discussed and rated as (i) not essential, (ii) useful but not essential, and (iii) essential; the content validity ratio (CVR) was calculated using Lawshe’s formula. Results: Data analysis revealed that of the 38 IYM practices, 18 exhibited significant content validity (cut-off value: 0.42, as calculated by applying Lawshe’s formula for the CVR). Conclusion: The IYM is valid for Primary dysmenorrhoea, with good content validity. However, future studies must determine the feasibility and efficacy of the developed module

Speed Control of Parallel Connected DSIM Fed by Six Phase Inverter with IFOC Strategy Using ANFIS

This paper describe the presentation of an IM for high load and high-power applications, this kind of applications the motor have a complex coupling between the field and torque. This can be achieve with assist of Indirect Field Oriented Control (IFOC) and parallel connection of two motors. The benefit is that parallel connection can provide the decoupled control of flux and torque for each motor and their concert in different operating environments. The Speed control of two Double Star Induction Motors working in parallel configuration with IFOC using a Fuzzy Logic Controller (FLC) and Adaptive Neuro Fuzzy Inference (ANFIS) controller is investigate in different operating environments. The two motors are connected in parallel at the output of a single six-phase PWM based inverter fed from a DC source. Performance of the projected method under load disturbances is studied through simulation using a MATLAB and evaluation of speed response of two controllers is analyzed. &nbsp

Exploratory studies on beneficiation of low-grade Banded Iron ore Formations (BIF) of Karnataka, India

Iron ore is the basic raw material for production of metallic iron. With depletion of high-grade resources and fine dissemination of valuable minerals in the abundantly available low-grade banded iron ore formations (BIF), liberation is achieved at finer sizes. Hence, it necessitated all beneficiation techniques to be operated at this finer size. However, physical separation techniques have limitations in separation efficiency. A combination of pre-concentration technique such as magnetic separation followed by flotation of magnetic fraction proved to be promising in achieving the respectable grade. A low-grade iron ore sample (BIF) of Karnataka, India was subjected to high intensity magnetic separation followed by flotation for enhancing its grade and recovery. Laboratory scale studies on this ore assaying 39.80 Fe%, 39.62 SiO2% and 1.73 Al2O3% indicated that it could be improved to 63.78 Fe%, 3.10 SiO2% and 1.01 Al2O3% at an overall iron recovery of 24% only. However, attempts are being made to further improve the iron recovery

Surgical management of middle and distal third fractures of scaphoid fixed with Herbert screw by volar approach

Surgical treatment of scaphoid fractures has evolved over the years to include variety of procedures and techniques. However scaphoid middle and distal third fractures fixation with Herbert screw by means of volar approach is a safe and effective method with good functional outcome and union rates. Our study concluded that management of middle and distal third scaphoid fractures with Herbert screw by volar approach gives excellent results in terms of union and recovery to daily activities. The wrist function improvement is more satisfactory, and the incidence of complications is low with this modality of treatment

P Wave Meson Spectrum in a Relativistic Model with Instanton Induced Interaction

On the basis of the phenomenological relativistic harmonic models for quarks we have obtained the masses of P wave mesons. The full Hamiltonian used in the investigation has Lorentz scalar + vector confinement potential, along with one gluon exchange potential (OGEP) and the instanton-induced quark-antiquark interaction (III). A good agreement is obtained with the experimental masses. The respective role of III and OGEP for the determination of the meson masses is discussed.Comment: Corrected typo

Preemptive Routing & Intrusion Detection for MANETs

An ad-hoc network will often change rapidly in topology, this courses for routes in the network to often disappear and new to arise. The Ad-hoc On-Demand Distance Vector Routing Protocol(AODV), is based on the principle of discover routes as needed. In this paper we will extend the definition of AODV with the ability to discover multiple routes to a host and switch between them, if an active route is becoming weak and there is a risk that it will disappear. We will refer to it as pre-emptive AOMDV . We will show that the performance of pre-emptive AOMDV do handle changes in topology better than AODV it self. To show the effect of extending AODV, the suggested protocol is implemented in a simulator. Performance enhancements will be presented from different scenarios, to compare pre-emptive AOMDV with the ordinary AODV. In this paper we also focus on intrusion detection based on Finite State Machine and cache memory in ad hoc networks. Security is one of the most important issues in current networks. The most common cases of attacks in mobile Ad hoc networks can be drop of routing packets and changes in the incoming packets which aims at disrupting the network routing and overall network reduce performance. The presented approach based on FSM focuses at recognizing the malicious nodes within the network in a fast and accurate way, then it deals with rapid introduction of the malicious nodes to other nodes in the network to prevent sending multiple packets and drop and packet change. Finally, we will show the significant improvement in comparison with others, we simulated our methods by NS2 software