Effect Of Carbon Composition Research Articles

Effect of carbon composition on permittivity performance of dielectric material from agricultural waste

Agriculture in several nations, including Malaysia, yields abundant waste like timber, oil palm waste, rice husks, coconut fibers, municipal waste, sugarcane residues, and pineapple byproducts. Fabricating a dielectric material from agricultural waste could curtail waste, offering an eco-friendly option for non-recyclable dielectrics in electronics devices such as PCBs, antennas, and sensors, for example. This research highlights the development of a new dielectric material using agricultural waste sourced from pineapple leaves. Pineapple leaves are selected as the primary raw material due to their abundant waste, which is often underutilized, particularly in Malaysia. The dielectric material is fabricated by incorporating pineapple leaves as the base formulation. Then, the fabricated material is characterized by its permittivity value and loss tangent. The permittivity value signifies the material's capacity to absorb or store electromagnetic waves. The analysis includes carbon composition and permittivity values to assess the dielectric potential of these raw materials. Elemental carbon composition is determined through energy-dispersive X-ray (EDX) analysis. The fabricated dielectric material achieves its highest permittivity value at 3.31, with a carbon percentage of 78.05% and an oxygen percentage of 21.95% within 16 runs of the two-level factorial analysis (TLFA) method. These findings indicate that an increased carbon element content enhances permittivity as carbon effectively absorbs and stores electromagnetic signals. Conversely, an increased oxygen element content reduces permittivity due to expanded void space (porous structure), diminishing the material's absorbent or storage capacity for electromagnetic signals. In conclusion, this initial experiment demonstrates that the carbon content of the fabricated dielectric material, derived from waste pineapple leaves, significantly influences its permittivity value.

Determination of Young’s Modulus of Aluminium, Copper, Iron, Brass and Steel Alloys by Using Double Exposure Holographic Interferometry (DEHI) Technique

Double Exposure Holographic Interferometry (DEHI) technique has wide applications in the field of science and engineering. DEHI can be used to determine very small surface changes in an object at very small interval of time. In present case, DEHI technique is used to record the hologram of the same object at different times subjected to different loads. This method has been advantageously used to determine Young’s Modulus (Y) of Aluminium, Copper, iron, brass and some steel alloys. It is found that the values of Y obtained by using DEHI technique are in close agreement with standard values of Y available for respective metals and their alloys. The method is also used to make standard relation between effect of carbon composition and Y of steel alloys.

Understanding Function and Performance of Carbon Additives in Lead-Acid Batteries

While the low cost and strong safety record of lead-acid batteries make them an appealing option compared to lithium-ion technologies for stationary storage, they can be rapidly degraded by the extended periods of high rate, partial state-of-charge operation required in such applications. Degradation occurs primarily through a process called hard sulfation, where large PbSO4 crystals are formed on the negative battery plates, hindering charge acceptance and reducing battery capacity. Various researchers have found that the addition of some forms of excess carbon to the negative active mass in lead-acid batteries can mitigate hard sulfation, but the mechanism through which this is accomplished is unclear. In this work, the effect of carbon composition and morphology was explored by characterizing four discrete types of carbon additives, then evaluating their effect when added to the negative electrodes within a traditional valve-regulated lead-acid battery design. The cycle life for the carbon modified cells was significantly larger than an unmodified control, with cells containing a mixture of graphitic carbon and carbon black yielding the greatest improvement. The carbons also impacted other electrochemical aspects of the battery (e.g., float current, capacity, etc.) as well as physical characteristics of the negative active mass, such as the specific surface area.

Atomistically Informed Extended Gibbs Energy Description for Phase-Field Simulation of Tempering of Martensitic Steel.

In this study we propose a unified multi-scale chemo-mechanical description of the BCT (Body-Centered Tetragonal) to BCC (Body-Centered Cubic) order-disorder transition in martensitic steel by adding the mechanical degrees of freedom to the standard CALPHAD (CALculation of PHAse Diagrams) type Gibbs energy description. The model takes into account external strain, the effect of carbon composition on the lattice parameter and elastic moduli. The carbon composition effect on the lattice parameters and elastic constants is described by a sublattice model with properties obtained from DFT (Density Functional Theory) calculations; the temperature dependence of the elasticity parameters is estimated from available experimental data. This formalism is crucial for studying the kinetics of martensite tempering in realistic microstructures. The obtained extended Gibbs energy description opens the way to phase-field simulations of tempering of martensitic steel comprising microstructure evolution, carbon diffusion and lattice symmetry change due to the ordering/disordering of carbon atoms under multiaxial load.

Effect of carbon content on plastic flow behaviour of plain carbon steels at elevated temperature

In the present study the effect of carbon composition on the hot flow behaviour of two different plain carbon steels is analysed. For this purpose the constitutive equations describing the stress–strain (σ–ϵ) relationships at a given strain rate ϵ and temperature T were determined for each steel. Uniaxial hot compression tests were performed to characterise the mechanical behaviour of the alloys. It was observed that irrespective of the test conditions, the low carbon steel displayed similar flow stresses to the high carbon steel. Comparison of the characteristic parameters of the constitutive equations describing the high temperature flow behaviour of these steels, together with values reported in the literature enabled determination of the effect of carbon content on flow behaviour. It has been found that flow stresses can be rationalised as a balance between work hardening and softening processes (basically dynamic recovery). At high temperatures and small strain rates, the high carbon steel showed lower hardening rates and slower dynamic recovery kinetics than the low carbon steel. In contrast, at low temperatures and large strain rates, the high carbon steel displayed higher hardening rates and recovery rates than the low carbon steel.