Review on thermal energy storage and eutectic nitrate salt melting point

In solar concentrates, thermal energy (TES) storage has a significant function (CSP). This article will discuss the forms of TES and TES content, focusing on the material for latent heat storage. Sensitive heat storage, latent heat storage and chemical reaction thermal storage classes can divide TES into three classes. Among the thermophysical properties for CSP is the latent heat storage content, which is used by more researchers. Dividing latent heat storage material into material for the organic, inorganic and eutetic phases change material (PCM). There are an advantage and downside to any form of storage material. Thermal stability at high temperature and low cost, however the specific heat capacity of the sensible heat storage material is very low compared to the latent heat storage materials.

Analysis of Four Historical Ciphers Against Known Plaintext Frequency Statistical Attack

The need of keeping information securely began thousands of years. The practice to keep the information securely is by scrambling the message into unreadable form namely ciphertext. This process is called encryption. Decryption is the reverse process of encryption. For the past, historical ciphers are used to perform encryption and decryption process. For example, the common historical ciphers are Hill cipher, Playfair cipher, Random Substitution cipher and Vigenère cipher. This research is carried out to examine and to analyse the security level of these four historical ciphers by using known plaintext frequency statistical attack. The result had shown that Playfair cipher and Hill cipher have better security compare with Vigenère cipher and Random Substitution cipher

Characterisation, performance and optimisation of nanocellulose metalworking fluid (MWF) for green machining process

The present research attempts to develop a hybrid coolant by mixing alumina nanoparticles with cellulose nanocrystal (CNC) into ethylene glycol-water (60:40) and investigate the viability of formulated hybrid nanocoolant (CNC-Al2O3-EG-Water) towards enhancing the machining behavior. The two-step method has been adapted to develop the hybrid nanocoolant at various volume concentrations (0.1, 0.5, and 0.9%). Results indicated a significant enhancement in thermal properties and tribological behaviour of the developed hybrid coolant. The thermal conductivity improved by 20-25% compared to the metal working fluid (MWF) with thermal conductivity of 0.55 W/m℃. Besides, a reduction in wear and friction coefficient was observed with the escalation in the nanoparticle concentration. The machining performance of the developed hybrid coolant was evaluated using Minimum Quantity Lubrication (MQL) in the turning of mild steel. A regression model was developed to assess the deviations in the tool flank wear and surface roughness in terms of feed, cutting speed, depth of the cut, and nanoparticle concentration using Response Surface Methodology (RSM). The mathematical modeling shows that cutting speed has the most significant impact on surface roughness and tool wear, followed by feed rate. The depth of cut does not affect surface roughness or tool wear. Surface roughness achieved 24% reduction, 39% enhancement in tool length of cut, and 33.33% improvement in tool life span. From this, the surface roughness was primarily affected by spindle cutting speed, feed rate, and then cutting depth while utilising either conventional water or composite nanofluid as a coolant. The developed hybrid coolant manifestly improved the machining behaviour

State-of-the-art review on electrolytes for sodium-ion batteries: Potential recent progress and technical challenges

Lithium batteries play a prominent role as a critical technology for advancing electric vehicles. However, establishing lithium-based technologies for mass storage encounters critical challenges such as materials availability and cost-efficiency. Hence, strategic approaches should be developed to address the existent challenges. Using sodium as new sustainable chemistry to replace lithium-based technologies tends to exhibit promising solution as the most appealing alternative. While exploring new electrode materials which has attracted significant interest from eminent researchers for sodium-ion batteries, research activities related to electrolyte are less attention paid. This paper reviews the most recent articles on developing and improving the electrolytes for sodium-ion batteries, particularly liquid electrolytes. This is the latest comprehensive discussion related to sodium-ion batteries with different type of electrolytes and a particular focus on the advantages/disadvantages in order to improve efficiency of these novel technologies as well as comprehensive discussion on the application of advanced nanomaterials towards these devices

Improved thermo-physical properties and energy efficiency of hybrid PCM/graphene-silver nanocomposite in a hybrid CPV/thermal solar system

In this research work, novel hybrid graphene-silver (Gr-Ag) nanomaterial has been used for first time with paraffin wax as a phase change material (PCM) to improve its thermo-physical properties. Thermal and electrical energy efficiencies of the novel synthesized nanocomposite (PCM/graphene-silver) has been investigated in solar thermal collector systems (CPV/T). This paper focuses on preparation, characterization, thermo-physical properties and energy efficiency in concentrated photovoltaic/thermal (CPV/T) system of new class of nanocomposites induced with hybrid Gr-Ag nanomaterial in three different concentrations. The specific heat capacity (cp) of hybrid PCM/graphene-silver nanocomposite increased by introducing hybrid Gr-Ag nanomaterial. Electrical and thermal energy performance of the hybrid PCM/graphene-silver is investigated in a CPV/T system using MATLAB 2017b program. The improvement of cp is found to be ~ 40% with 0.3 mass% of hybrid Gr-Ag nanomaterial loaded in PCM. The highest thermal conductivity increment is found to be ~ 11% at 0.3 mass% concentration of hybrid Gr-Ag nanomaterial in PCM. The endothermic enthalpy value of the hybrid PCM/graphene-silver nanocomposite is found to be ~ 75.6 J g−1 at 0.1 mass% loading concentration of hybrid Gr-Ag nanomaterial. Melting point of hybrid PCM/graphene-silver nanocomposite with loading concentration of 0.3 mass% is measured to be 73.2 °C. The highest thermal efficiency using the hybrid graphene-silver nanoparticles reached the value of 39.62% which represents 4.16% increment in comparison with the pure PCM. The equivalent electrical efficiency is improved by 2.8% at the loading concentration of 0.3 mass% of the hybrid Gr-Ag nanomaterial. These new class of nanocomposites represented the capability of enhancement in the performance of the CPV/T system consisting of lower PV temperatures, higher temperature gains across the cooling fluid and higher electrical and thermal efficiencies

Graphene nanoplatelets–cellulose nanocrystals in engine oil for automotive applications

The friction and wear of worn surfaces is a principal cause of energy dissipation in automobile engines. The current study investigates graphene nanoplatelets (GNPs), based on a carbon allotrope, that have good thermal, physical and chemical properties, and cellulose nanocrystals (CNCs) as a universal nano-sized ecological biopolymer. In view of this, the objective of the present work is to enhance the tribological behavior and lubricant properties using hybrid GNPs and CNCs blended with SAE 40 engine oil with various concentrations in the range 0.01–0.10%. The characterization was carried out by using different techniques such as X-ray diffraction (XRD) and field emission scanning electron microscopy (FESEM). The XRD patterns confirmed the platelet structure of GNPs, and FESEM showed that the sizes of small and agglomerated particles were 20–50 and 200 nm for GNPs and CNCs, respectively. Scanning electron microscopy morphological evaluation was conducted for all volumetric concentrations of single and hybrid nanolubricants. Morphological investigation indicated that there is homogeneous dispersion and there is a smoother surface after using graphene:CNC nanolubricants compared with that using just SAE 4

Enhancing Machining performance in Stainless Steel Machining using MXene Coolant: A Detailed Examination

Metal cutting, a complex process in manufacturing, involves various factors that significantly affect the quality of the final product. Notably, the turning process is crucial, with outcomes that heavily depend on multiple machining parameters. These parameters encompass speed, depth of cut, feed rate, the type of coolant used (specifically, high heat transfer MXene coolant), and insert types, among others. The material of the workpiece is also a critical factor in the metal-cutting operation. This study focuses on achieving optimal surface quality and minimizing cutting forces in the turning process. It recognizes the substantial impact of numerous process parameters, directly or indirectly affecting the product's surface roughness and cutting forces. Understanding these optimal parameters can lower machining costs and improve product quality. Our research concentrates on turning a stainless-steel alloy workpiece using a carbide insert tool. We employ the Response Surface Method (RSM) to optimize cutting parameters within a set range of cutting speed (100, 125, 150 m/min), feed rate (0.1, 0.2, 0.3 mm/rev), and depth of cut (0.4, 0.8, 1.2 mm). Additionally, we use various tool geometries and the RSM design of experiments to enhance and analyze the multi-response parameters of surface roughness and tool life. Optimal machining parameters for MXene-NFC involve a cutting speed of 140 m/min, a feed rate of 0.05 mm/rev, and a depth of cut of 0.5 mm. These settings ensure minimal surface roughness, maximum tool life, and the greatest total length of cut, achieving a composite desirability of 0.695

Experimental analysis on the performance, combustion/emission characteristics of a DI diesel engine using hydrogen in dual fuel mode

Among alternative fuels, hydrogen has significant promise as both a fuel and a carrier of energy. Hydrogen is projected to be a key alternative fuel in the near future to meet stringent pollution standards. Internal combustion (IC) engines, gas turbine, and aerospace industries use hydrogen as a fuel because it is non-toxic, odorless with high calorific value (CV), and combustible across a wide temperature range while also being a long-term renewable and less polluting energy source. The objective of this study is to investigate the impact of using different hydrogen rations on combustion behaver, engine performance, and emission characteristics in a dual fuel compressed ignition (CI) diesel engine. The tests were performed at speeds of 1500, 2000, and 2500 rpm at difference operating conditions. Hydrogen was introduced at flow rates of 21.4, 28.5, 36.2, 42.8, and 49.6 L per minute for each load. The findings reveal that hydrogen flow rate of 21.4 l/min and 42.8 l/min gives significant impact to engine coefficient of variation (COV) and the performance of the engine. In addition, the emissions level of CO, CO2 and smoke were improved at the same flow rate. Moreover, the break thermal efficiency (BTE) has shown significant improvement at 21.4 l/min of hydrogen flow rate due to the reduction in combustion length and the movement of the combustion phasing toward the ideal phase. The use of hydrogen as alternative energy has important role as a future green energy source

Enhancing stability and tribological applications using hybrid nanocellulose-copper (II) oxide (CNC-CuO) nanolubricant: An approach towards environmental sustainability

The primary aim of the present study is to assess the stability and efficacy of hybrid nanocellulose (CNC) and copper (II) oxide (CuO) nanoparticles when integrated into engine oil as a lubricant for piston ring-cylinder liner applications. The assessment of system stability was conducted by employing zeta potential measurements. Furthermore, the coefficient of friction and specific wear rate were determined by using hydrodynamic lubrication in circumstances characterised by high speed and low load, as well as boundary lubrication in situations characterised by low speed and high load. The trials used a specially constructed friction and wear testing device miming the contact geometry between piston rings and cylinder liners in an internal combustion engine. Alongside SAE 40 oil, several nanoparticle concentrations (0.1%, 0.3%, 0.5%, 0.7%, and 0.9% added to SAE 40) were examined. The stability of the nanolubricant increased from 0.1% to 0.5% concentration and then declined at 0.9% concentration, according to the zeta potential data. The graph showed that the 0.5% concentration of the nanolubricant had the highest mean zeta potential, indicating exceptional stability. The CNC-CuO nanolubricants showed notable reductions in the friction coefficient regarding tribological performance. The friction coefficient reduced between 33% and 44% in mixed lubrication and 48% and 50% in boundary lubrication. There was a 9–13% decrease in the friction coefficient when hydrodynamic lubrication was used. The CNC-CuO nanolubricant only showed light scuffing, while the SAE 40 sample showed severe exfoliation and scuffing. Wear rates had been enhanced by 33.5%. Overall, the 0.5% concentration of CNC-CuO nanoparticles improved the engine oil's thermophysical properties and performance

Improved Thermophysical Properties of Developed Ternary Nitrate-Based Phase Change Material Incorporated with MXene as Novel Nanocomposites

In this study, nanocomposite of ternary nitrate molten salt induced with MXene is developed. LiNO3-NaNO3- KNO3 with wt% of 35:12:53 and 35:10:55 are produced and doped with MXene in the wt% of 0.2, 0.5, 1.0, and 1.5. FTIR result indicates the composites had no chemical reaction occurred during the preparation. UV-VIS analysis shows the absorption enhancement with respect to the concentration of MXene. Thermogravimetric analysis (TGA) was used to measure the thermal stability of the LiNO3-NaNO3-KNO3 induced with MXene. The ternary molten salts were stable at temperature range of 600–700°C. Thermal stability increases with the addition of MXene. 1.5 wt% of MXene doped with LiNO3-NaNO3-KNO3 with wt% 35:10:55 and 35:12:53, increases the thermal stability from 652.13°C to 731.49°C and from 679.82°C to 684.57°C, respectively. Using thermophysically enhanced molten salt will increase the efficiency of CS