Determination of Fatigue Limit of Coir/CNT/Fly Ash Reinforced Epoxy Polymer Matrix Composite

In the quest of new material development, polymer matrix composite plays prominent role. Instead of reinforcing synthetic material in the polymer composite, an attempt is made in this work to reinforce green/recyclable/reusable materials in the polymer composite. Composite specimens are made with epoxy as matrix and coir/CNT/fly ash as reinforcements. The influences of wt.% of coir/CNT/fly ash on fatigue behavior of composite are determined. Response Surface Methodology (RSM), a Design of Experiments (DOE) approach is followed in specimen preparation and testing. ANOVA is used to find the influences of different parameters such as wt.% of coir/CNT/fly ash on fatigue behavior of composite. Optimized levels of parameters are also found out

Computational Buckling Analysis of Epoxy-Based Composite Reinforced with Sugarcane Fiber, Fly-Ash, and Carbon Nanotube

Abstract Industries play a very vital role in the developed nation. Proportional to the higher production capacity of these industries, there is a surge in the quantity of waste material being discharged. This waste material can be put to effective use; a considerable way is by creating a green composite that is long-lasting, and concocted by using natural fibers and environment-friendly materials as reinforcements. In the following study, an attempt is made to investigate the buckling characteristics of a thin geometrical plate of epoxy-based composite reinforced with Sugarcane fiber/ Fly-ash/ Carbon Nanotube. The investigative study was conducted numerically on the plate by applying axially compressive load. To procure an optimized result on the weight percentages of the composition of the fiber in the composite material, the DOE/optimization tool i.e. a mathematical and statistical technique known as the Response Surface Methodology (RSM) was used. Essential geometrical modeling and the appropriate boundary conditions for the buckling analysis were carried out using the Static Structural and Eigen Buckling standalone systems in the ANSYS software. The analytical tool, Analysis of Variance (ANOVA) was utilized to investigate the influential degree of reinforcement variables on buckling characteristics present in the composite. The results reveal that the critical buckling loads escalate for higher weight percentages for carbon nanotube and fly-ash reinforcements in the composite composition. The optimized parameters obtained can be incorporated to achieve improved critical buckling load and hence many synthetic composites were replaced thus enhancing the sustainability of the environment

Switching the orientation of Jahn-Teller axes in oxime-based Mn(III) dimers and its effect upon magnetic exchange:a combined experimental and theoretical study

A family of Mn-III dimers of general formula [Mn-2(III)(R-sao)(2)(dpa)(2)](ClO4)(2) (1-5) has been synthesised using derivatised phenolic oximes (R-saoH(2), where R = H, Me, Et, Ph) in combination with di-(2-picolyl)-amine (dpa). Their structures reveal a double-oxime bridged [Mn-III(NO)](2) magnetic core in which the Jahn-Teller axes lie perpendicular to the bridging plane, in contrast to two previously reported family members (6, 7). The switch in the orientation of the Jahn-Teller axes is enforced through the use of the chelating ligand which is present in 1-5 and absent in 6-7. Dc magnetic susceptibility measurements reveal that the exchange interactions between the MnIII metal centres in 1-5 are antiferromagnetic in contrast to that observed for 6 and 7 which are ferromagnetic. DFT calculations performed on complexes 1-6 reproduce both the sign and strength of the J values found experimentally. Molecular orbital analysis unlocks a common mechanism of magnetic coupling based upon the orientation of the Jahn-Teller axis, with the magneto-structural correlation also dependent upon the Mn-N-O-Mn angles - with ferromagnetic interactions at smaller dihedral angles

Mixed d-f Block Single-Molecule Toroics

Single Molecule Toroics pp 15–66Cite as Mixed d-f Block Single-Molecule Toroics Keith S. Murray, Stuart K. Langley, Kuduva R. Vignesh, Gopalan Rajaraman, Kieran Hymas & Alessandro Soncini Chapter First Online: 24 November 2022 3 Accesses Abstract In this chapter, we focus on the single-molecule toroidal (SMT) behaviour of a family of “double dysprosium triangle” heptanuclear species which contain a bridging d-block M(III) or a p-block M(III) ion. They are of general formula [MIIIDyIII 6(OH)8(o-tol)12(NO3)(MeOH)5]∙3MeOH, labelled MDy 6, where o-tol = o-toluate. The parent compound has M = Cr, with subsequent family members having M = Mn, Fe, Co and Al, the latter two having diamagnetic M(III) centres. This heptanuclear family could also be made using chloride as counter-anion rather than nitrate, the molecular structures being similar to the nitrates though the unit cells are different. The LnIII ion could also be varied to include Tb, Ho and Er and, thus, allow exploration of SMT behaviour in non-Dy analogues. The syntheses, structures and magnetic and EPR properties are described, starting with the parent CrDy 6. Theoretical calculations are described in detail, with MOLCAS methods employed to determine anisotropy directions, blocking barriers and relaxation effects and a newly developed model used to calculate magnetically coupled toroidal states and the role of these states in spin dynamics. The direct simulation of the micro-Squid magnetic hysteresis loops of all family members is described as well as that of the original Dy 3 material. Toroido-structural correlations are presented with strategies developed to optimize the important ferrotoroidic coupling between Dy3 triangles in these heptanuclear toroidal species. Finally, we give a brief summary of SMT behaviour in ring-shaped 3d-4f toroidal species

Fuzzified swarm intelligence framework using FPSOR algorithm for high-speed MANET- Internet of Things (IoT)

Internet of things (IoT) is an inventive technology which permit the association of physical things by means of the digital world throughout the use of heterogeneous networks and communication technologies. Ad-hoc routing protocols may be dispersed and involve every node in route discovery process by making routing data more reliable. Mobile-Adhoc-Networks (MANETs) consist of many portable nodes that can commune directly with each other or through intermediate nodes. Repeatedly, nodes in a MANETs operate with batteries and can roam freely, and thus, a node may exhaust its energy or move away without providing any notice to its cooperative nodes. IoT system using a combination of MANET, a route consists of numerous links in sequence, and so, its lifetime is based on the lifetime of every node and also the wireless links among adjacent nodes. In this research work Fuzzified Particle Swarm Optimization oriented Routing (FPSOR) algorithm is planned to minimize data loss and computational overhead, which in turn maximizes the lifetime of MANETs. Particle Swarm Optimization oriented Routing protocol (PSOR) have taken energy competence as significant criterion for processing routing and driving optimized path for the data accelerating and processing to the source node. The PSOR produces a fresh route for routing by considering fitness value of energy to evaluate diverse path and to choose best-optimized path whose energy consumption is less as compared to ant colony optimization routing paths. This algorithm utilizes a good approach focusing energy levels/status of the nodes through fuzzification and the lengths of the routed ways. NS2 simulator is casted for performance evaluation

Investigation of Tensile Behavior of Carbon Nanotube/Coir Fiber/Fly Ash Reinforced Epoxy Polymer Matrix Composite

Fiber-reinforced composite materials are lightweight and can withstand heavy loading conditions. Reinforcement augments the strength of the composite material, which is assessed by its elastic modulus. An attempt is made to reinforce epoxy with Coir Fiber, Carbon Nanotube (CNT) and Fly-ash. Central Composite Design (CCD), a Response Surface Methodology (RSM) tool, which is a Design of Experiment (DOE) technique, is used to fabricate the experimental samples to study their tensile behavior. Analysis of variance (ANOVA) is employed to investigate the effect of reinforcement percentage of CNT, coir-fiber, and fly-ash on tensile behavior of composite. The ANOVA results follow the trend of the experimental values with a deviation of less than 10% in yield strength, tensile strength, and Young’s modulus. Two models (Artificial Neural Network and Multiple Linear Regression Model) originated resting on the regression equation to speculate the elastic modulus for various reinforcement parameters using the experimental data. The main objective is to optimize reinforcement parameters using both the models having a maximum elastic modulus of 2.602 GPa and 2.682 GPa, respectively, which is achieved by the teaching learning-based optimization technique. Furthermore, confirmation experiments validate the optimization process with an error of less than 4%

Exploring the Influence of Diamagnetic Ions on the Mechanism of Magnetization Relaxation in {Co^III₂Ln^III₂} (Ln = Dy, Tb, Ho) “Butterfly” Complexes

The synthesis and magnetic and theoretical studies of three isostructural heterometallic [Co^III₂Ln^III₂(μ₃-OH)₂(<i>o</i>-tol)₄(mdea)₂(NO₃)₂] (Ln = Dy (<b>1</b>), Tb (<b>2</b>), Ho (<b>3</b>)) “butterfly” complexes are reported (<i>o</i>-tol = <i>o</i>-toluate, (mdea)^2– = doubly deprotonated <i>N</i>-methyldiethanolamine). The Co^III ions are diamagnetic in these complexes. Analysis of the dc magnetic susceptibility measurements reveal antiferromagnetic exchange coupling between the two Ln^III ions for all three complexes. ac magnetic susceptibility measurements reveal single-molecule magnet (SMM) behavior for complex <b>1</b>, in the absence of an external magnetic field, with an anisotropy barrier <i>U</i>_eff of 81.2 cm^–1, while complexes <b>2</b> and <b>3</b> exhibit field induced SMM behavior, with a <i>U</i>_eff value of 34.2 cm^–1 for <b>2</b>. The barrier height for <b>3</b> could not be quantified. To understand the experimental observations, we performed DFT and ab initio CASSCF+RASSI-SO calculations to probe the single-ion properties and the nature and magnitude of the Ln^III–Ln^III magnetic coupling and to develop an understanding of the role the diamagnetic Co^III ion plays in the magnetization relaxation. The calculations were able to rationalize the experimental relaxation data for all complexes and strongly suggest that the Co^III ion is integral to the observation of SMM behavior in these systems. Thus, we explored further the effect that the diamagnetic Co^III ions have on the magnetization blocking of <b>1</b>. We did this by modeling a dinuclear {Dy^III₂} complex (<b>1a</b>), with the removal of the diamagnetic ions, and three complexes of the types {K^I₂Dy^III₂} (<b>1b</b>), {Zn^II₂Dy^III₂} (<b>1c</b>), and {Ti^IV₂Dy^III₂} (<b>1d</b>), each containing a different diamagnetic ion. We found that the presence of the diamagnetic ions results in larger negative charges on the bridging hydroxides (<b>1b</b> > <b>1c</b> > <b>1</b> > <b>1d</b>), in comparison to <b>1a</b> (no diamagnetic ion), which reduces quantum tunneling of magnetization effects, allowing for more desirable SMM characteristics. The results indicate very strong dependence of diamagnetic ions in the magnetization blocking and the magnitude of the energy barriers. Here we propose a synthetic strategy to enhance the energy barrier in lanthanide-based SMMs by incorporating s- and d-block diamagnetic ions. The presented strategy is likely to have implications beyond the single-molecule magnets studied here

Exploring the Influence of Diamagnetic Ions on the Mechanism of Magnetization Relaxation in {Co^III₂Ln^III₂} (Ln = Dy, Tb, Ho) “Butterfly” Complexes

The synthesis and magnetic and theoretical studies of three isostructural heterometallic [Co^III₂Ln^III₂(μ₃-OH)₂(<i>o</i>-tol)₄(mdea)₂(NO₃)₂] (Ln = Dy (<b>1</b>), Tb (<b>2</b>), Ho (<b>3</b>)) “butterfly” complexes are reported (<i>o</i>-tol = <i>o</i>-toluate, (mdea)^2– = doubly deprotonated <i>N</i>-methyldiethanolamine). The Co^III ions are diamagnetic in these complexes. Analysis of the dc magnetic susceptibility measurements reveal antiferromagnetic exchange coupling between the two Ln^III ions for all three complexes. ac magnetic susceptibility measurements reveal single-molecule magnet (SMM) behavior for complex <b>1</b>, in the absence of an external magnetic field, with an anisotropy barrier <i>U</i>_eff of 81.2 cm^–1, while complexes <b>2</b> and <b>3</b> exhibit field induced SMM behavior, with a <i>U</i>_eff value of 34.2 cm^–1 for <b>2</b>. The barrier height for <b>3</b> could not be quantified. To understand the experimental observations, we performed DFT and ab initio CASSCF+RASSI-SO calculations to probe the single-ion properties and the nature and magnitude of the Ln^III–Ln^III magnetic coupling and to develop an understanding of the role the diamagnetic Co^III ion plays in the magnetization relaxation. The calculations were able to rationalize the experimental relaxation data for all complexes and strongly suggest that the Co^III ion is integral to the observation of SMM behavior in these systems. Thus, we explored further the effect that the diamagnetic Co^III ions have on the magnetization blocking of <b>1</b>. We did this by modeling a dinuclear {Dy^III₂} complex (<b>1a</b>), with the removal of the diamagnetic ions, and three complexes of the types {K^I₂Dy^III₂} (<b>1b</b>), {Zn^II₂Dy^III₂} (<b>1c</b>), and {Ti^IV₂Dy^III₂} (<b>1d</b>), each containing a different diamagnetic ion. We found that the presence of the diamagnetic ions results in larger negative charges on the bridging hydroxides (<b>1b</b> > <b>1c</b> > <b>1</b> > <b>1d</b>), in comparison to <b>1a</b> (no diamagnetic ion), which reduces quantum tunneling of magnetization effects, allowing for more desirable SMM characteristics. The results indicate very strong dependence of diamagnetic ions in the magnetization blocking and the magnitude of the energy barriers. Here we propose a synthetic strategy to enhance the energy barrier in lanthanide-based SMMs by incorporating s- and d-block diamagnetic ions. The presented strategy is likely to have implications beyond the single-molecule magnets studied here