Effect of Carbon nanotubes/nanofibers Reinforcement on Mechanical and Thermal Properties of CFRPs

Multiwalled carbon nanotubes (MWCNTs) were purified to ultra high purity levels (99.9%) by high temperature (26000C) heat treatment method. It was observed that, the structural perfection of MWCNTs increased besides improvement in their purity. Based on the TGA, XRD, TEM and Raman spectroscopy studies mechanisms are proposed for the observed structural changes to MWCNTs. These mechanisms says that, during high temperature treatment, the innermost walls of the MWCNTs collapse due to thermal stresses. However, it was observed that, as long as some traces of the metallic impurities are present, they suppress the collapse of the internal walls. Once the metallic impurities are removed, structural distortion of MWCNTs takes place. It was observed that heat treatment for 60 mins is optimum to obtain highly pure and structurally perfect MWCNTs. These purified MWCNTs were subsequently amino functionalised. FT-IR and XPS methods were used to ascertain the functional groups present on the MWCNTs

Analysis of Irregular High Raised RCC Buildings by Using Tuned Mass Damping System

Tall buildings are indispensable in urban areas due to high cost of land, shortage of open spaces and scarcity of lands. The tall buildings are in general highly vulnerable to lateral forces arising out of cyclones and earthquakes. Designing the structures to withstand these occasional lateral forces is very expensive; hence it is not always desirable. The measures to reduce the lateral forces are by way of reducing the weight of the structure and by reducing the exposed faces to thwart wind. However the architectural requirement and the utility of the building have to be honored at all times by the structural designer. Though the technique of Tuned mass damping (TMD) is very well appreciated, the mathematical implications involved in finding the magnitude of mass, stiffness and damping of the TMD is highly intricate and suitable TMD system for a given building structure, which shall remain an integral part of the structure itself, placed on top of the building yet serves the purpose of reducing the earthquake effects on buildings. The TMD methodology adopted for three irregular R.C. framed models having + (Plus)-shape , C-shape and T-shape in plan. This apart the device shall find its utility for all zones of seismic activity and ground/structural conditions and introduces various structural motion control methodologies with focus on tuned mass damping systems. The control properties and some aspects of TMD parameters are outlined. ETABS software is used for dynamic analysis of various shapes of the framed buildings

AN AUTONOMOUS MOBILE ROBOT FOR REFINERY INSPECTION

Industrial safety is one of the main aspects of industry specially refining industry. To avoid any types of unwanted phenomena all refining industry follows some basic precaution and phenomena. Communication is the main key factor for any industry today to monitor different parameters and take necessary actions accordingly to avoid any types of hazards.To implement a robotic system to autonomously navigate in an oil and gas refinery and it must be able to communicate with the control room and also localize it and alert workers in hazardous leakages and other accidents. Oil and gas refineries can be a dangerous environment for numerous reasons, including heat, gasses and humidity at the refinary. In order to augment how human operators interact with this environment, a mobile robotic platform is developed. This paper focuses on the use of WiFi for communicating with and localizing the robot. All the algorithms implemented are tested in real world scenarios with the robot developed and results are promising

Effect of carbon nanofibre addition on the mechanical properties of different Vf carbon-epoxy composites

Carbon-epoxy (C-epoxy) laminated composites having different fibre volume fractions (40, 50, 60 and 70) were fabricated with and without the addition of aminofunctionalized carbon nanofibres (A-CNF). Flexural strength, interlaminar shear strength (ILSS) and tensile strength of the composite laminates were determined. It was observed that, the ability of A-CNF to enhance the mechanical properties of C-epoxy diminished significantly as the fibre volume fraction (Vf) of the C-epoxy increased from 40 to 60. At 70Vf, the mechanical properties of the ACNF reinforced C-epoxy were found to be lower compared to the C-epoxy composite made without the addition of A-CNF. In this paper suitable mechanisms for the observed trends are proposed on the basis of the fracture modes of the composite

Family of PRGs based on Collections of Arithmetic Progressions

We consider the mathematical object: \textit{collection of arithmetic progressions} with elements satisfying the property: \textit{$j^{th}$ terms of $i^{th}$ and $(i+1)^{th}$ progressions of the collection are multiplicative inverses of each other modulo the $(j+1)^{th}$ term of $i^{th}$ progression}. Under a \textit{certain} condition on the common differences of the progressions, such a collection is {\em uniquely} generated from a pair of co-prime seed integers. The object is closely connected to the standard Euclidean gcd algorithm. In this work, we present one application of this object to a novel construction of a new family of pseudo random number generators (PRG) or symmetric key ciphers. We present an authenticated encryption scheme which is another application of the defined object. In this paper, we pay our attention to a basic symmetric key method of the new family. The security of the method is based on a well-defined hard problem. Interestingly, a special case of the hard problem (defined as Problem A) is shown to be computationally equivalent to the problem of factoring integers. The work leaves some open issues, which are being addressed in our ongoing work

Effect Of Nanoclay On The Toughness Of Epoxy And Mechanical, Impact Properties Of E-glass-epoxy Composites

Organically modified montimorillonite nanoclay was added to the epoxy and E-glass-epoxy composites. The influence of nanoclay content (varied between 0 to 5wt %) on the relative crosslink density and the fracture toughness of the epoxy matrix was studied. Differential scanning calorimetry (DSC) indicated that the amino functional groups present on the nanoclay react with the epoxy matrix to increase the crosslink density of about 13 and 18% at 3 and 5wt% addition, respectively. The toughness of the epoxy composites increased by 25% at 3wt% addition of nanoclay, whereas, it decreases at 5wt%. Flexural strength and tensile strength of the E-glass-epoxy composites were found to increase by 12% and 11% respectively at 3wt% addition of nanoclay, while at 5wt% addition these properties decreased due to the matrix embrittlement. Interestingly matrix embrittlement is found to be beneficial in increasing the impact resistance due to spallation of embrittled matrix that ensures the dissipation of the impact energy. 5wt% nanoclay addition increases the impact strength by 29% and reduces the back face bulge of composite by 31%. These results may lead to the design and realization of glass-epoxy composites with better impact strength

Synthesis, Spectral Characterization and Antimicrobial Studies of Co(II) Complexes with Tetradentate Schiff bases Derived from Ortho-Phthalaldehyde

A series of cobalt (II) complexes have been synthesized with Schiff bases derived from ortho-phthalaldehyde and various amines in aqueous methanol solution. The newly synthesized Schiff bases and their Co (II) complexes have been characterized  by elemental analysis, magnetic susceptibility, thermal, conductance measurements, mass, IR, electronic, 1H,13C-NMR spectral techniques. These ligands act as tetradentate species and coordinate to the metal center through the different potential donor atoms such as N, O and S. The probable octahedral structures have been assigned to these complexes. All the synthesized Schiff base ligands and Co(II) metal complexes have also been screened for their antimicrobial activities and metal complexes found to be more active than respective Schiff-base ligands

Effect of high-temperature heat treatment duration on the purity and microstructure of MWCNTs

The effect of high-temperature heat treatment on purity and structural changes of multiwalled carbon nanotubes (MWCNTs) were studied by subjecting the raw MWCNTs (pristine MWCNTs) to 2600∘C for 60 and 120 min. Thermogravimetric analysis (TGA), X-ray diffraction, Raman spectroscopy, transmission electron microscopy (TEM) and scanning electron microscopy (SEM) were used to study the effect of heat-treatment duration on the purity and structural changes of MWCNTs. Results show that high-temperature heat treatment can be used to purify MWCNTs with proper optimization of treatment time. It was observed that 60 min heat treatment of raw MWCNTs imparts high purity and structural perfection to MWCNTs, while 120 min heat treatment imparts structural degradation to MWCNTs with collapse of the innermost shells. The present study indicates that metal impurities act as moderators in controlling the degradation of MWCNTs up to certain duration, and once the metal impurities escape completely, further heat treatment degrades the structure of MWCNTs

Comparison of push-out bond strength of bioceramic sealer with bioceramic coated and non-bioceramic coated Guttapercha: an in vitro study

Background: The goal of the endodontic treatment is to achieve a fluid-tight impervious seal to prevent the ingress of bacteria and the occurrence of any pathology in future. The endodontic sealer plays a crucial role in obtaining the hermetic seal by filling all the spaces and by binding to the root dentin and to the core obturating material, which is usually gutta-percha. Aim: This study aimed to compare the push-out bond strength of Endosequence BC sealer with bioceramic coated gutta-percha and non-bioceramic coated gutta-percha. Materials and methods: A total of 36 extracted human maxillary central incisors were decoronated to standardize the root length of 15mm. Working length was determined and Biomechanical preparation for all the samples was done with a Mtwo (VDW Company) rotary file till 40/.06. Samples were randomly divided into three groups containing 12 teeth in each group based on the obturation procedure, namely Group 1: Endosequence BC sealer along with Endosequence bioceramic coated gutta-percha (n=12), Group 2: Endosequence BC sealer along with normal gutta-percha (n=12), Group 3: AH Plus sealer along with normal gutta-percha. All the samples were obturated using single cone technique. The specimens were sectioned orthogonally at middle third to obtain three sections of 1mm thick. All the samples were subjected to the push-out bond strength test with the universal testing machine. The data were subjected to one-way Analysis of Variance (ANOVA) followed by post hoc analysis. Results: Samples obturated with Endosequence BC sealer with Endosequence bioceramic coated gutta-percha showed the maximum push-out bond strength followed by Group 3 and Group 2.  One-way Anova showed significant differences (p=0.021) among the groups. In posthoc analysis, the specimens from group 1 exhibited significant differences (p=0.016) with the group 2 specimens. Conclusion: The push-out bond strength of Endosequence Bioceramic sealer with Endosequence Bioceramic coated gutta-percha was significantly higher than that of Endosequence Bioceramic sealer with normal gutta-percha and AH Plus sealer with normal gutta-percha