New inorganic nanomaterials for low-voltage transistor applications

This research aims to synthesise and characterise solution-processable high-k dielectric nanorods, which are potentially suitable for use as the dielectric layer in low-voltage Organic Field-Effect Transistor (OFET) applications. Oleic acid-stabilised titanium dioxide nanorods (TiO₂-OA), metal-doped anatase titanium oxide (TiO₂-OA-M; M=Nb, In, or Nb/In) nanorods, rutile titanium oxide nanorods (TiO₂) and barium titanium oxide nanorods (BaTiO₃) have been prepared and investigated.Solution processable oleic acid-stabilised titanium dioxide nanorods (TiO₂-OA) have been prepared by hydrolysis of titanium (IV) tetraisopropoxide (TTIP) with oleic acid (OA) as surfactant in the presence of trimethylamine N-oxide (TMAO). Furthermore, a series of ligand exchange reactions were carried out to replace the oleic acid bonded on the surface of TiO₂-OA with diethyl 2-phenylethyl phosphonate (DEPPNA), octadecylphosphonic acid (ODPA) or octylphosphonic acid (OPA). The ligand exchange rate was characterised by a combination of 31P liquid NMR, ICP, CHN, and FT-IR. The solubility of the ligand-exchanged products in chlorobenzene was also investigated.A novel method based on the co-hydrolysis of titanium (IV) tetraisopropoxide (TTIP) and niobium or/and indium isopropoxide or ethoxide has been investigated to prepare solution-processable, oleic acid- stabilised, niobium- and indium-doped, anatase TiO₂ nanorods (TiO₂-OA-M; M = Nb, In or Nb/In). The effect of niobium and indium precursors, the molar ratio of Nb or In precursors/TTIP and reaction time on the composition, structure and morphology of the Nb or In doped TiO₂ products have been investigated by a combination of XPS, XRD, ICP, CHN, FT-IR and TEM. Furthermore, a series of ligand exchange reactions were carried out to replace the oleic acid, which is bonded on the surface of TiO₂-OA-M, with diethyl 2-phenylethyl phosphonate (DEPPNA) or octadecylphosphonic acid (ODPA). The solubility of the products in chlorobenzene was also investigated.Rutile titanium dioxide nanorods with different sizes were prepared by three different approaches. In the first approach，hair-like rutile nanorods TiO₂ were prepared by simple hydrolysis of a TiOCl₂ solution at low temperature (50, 70 and 90 °C). In the second approach, rutile nanorods TiO₂ with a length of 150-200 nm and a width of 25-40 nm were prepared by using a hydrothermal treatment of TiOCl₂ at 220 °C. In the third approach, rutile nanorods TiO₂ with length of 80 nm and diameter of 20 nm were prepared by using an hydrothermal reaction of TiOCl₂ in the presence of 3-hydroxytyramine hydrogen chloride, [(HO)₂C₆H₃CH₂CH₂NH₂·HCl] at 150°C. In order to improve the solubility of the obtained rutile titanium dioxide nanorods in organic solvents, different surface-modification methods have been investigated to coat the surface of the rutile titanium dioxide nanorods with various organic ligands. In the first method, a modification of the TiO₂ nanorods with oleic acid (OA) in chlorobenzene was investigated. In the second method, a two-stage treatment of TiO₂ nanorods in an acidic medium was studied, using a selection of oleic acid (OA), diethyl 2-phenylethyl phosphonate (DEPPNA), octylphosphonic acid (OPA) and decylphosphonic acid (ODPA) as ligands. In the third method, wet TiO₂ nanorods before dry was directly modified with a range of oleic acid and amines, e.g., octylamine, dodecylamine and hexadecylamine, as ligands. All the products were characterized by a combination of XRD, ICP, CHN, FT-IR and TEM.The preparation of barium titanium oxide nanorods (BaTiO₃) has been investigated by different approaches. In the first approach, a hydrothermal reaction was carried out to convert the titanium dioxide nanorods prepared in the first and third parts in this research into BaTiO₃ nanorods. The effect of the molar ratio of Ba/Ti, the reaction pH, reaction time and temperature on the composition, structure and morphology of the products were fully investigated. In the second approach, a hydrothermal reaction using a single source Ba/Ti precursor, i.e., barium titanium ethylhexano-isoproxide BaTi(O₂CC₇H₁₅)(OC₃H₇)₅, was carried out to prepare barium titanium oxide nanorods. In the third approach, barium titanium oxide nanorods were prepared by using a hydrothermal reaction between barium chloride (BaCl₂) and titanium oxy chloride (TiOCl₂) in the presence of ethylene glycol as surfactant. All the products have been characterised by a combination of XRD, ICP, CHN, FT-IR and TEM

Machine Learning-Based Approach for Modeling the Nanofluid Flow in a Solar Thermal Panel in the Presence of Phase Change Materials

Considering the importance of environmental protection and renewable energy resources, particularly solar energy, the present study investigates the temperature control of a solar panel using a nanofluid (NFD) flow with eco-friendly nanoparticles (NPs) and a phase change material (PCM). The PCM was used under the solar panel, and the NFD flowed through pipes within the PCM. A number of straight fins (three fins) were exploited on the pipes, and the output flow temperature, heat transfer (HTR) coefficient, and melted PCM volume fraction were measured for different pipe diameters (D_Pipe) from 4 mm to 8 mm at various time points (from 0 to 100 min). Additionally, with the use of artificial intelligence and machine learning, the best conditions for obtaining the lowest panel temperature and the highest output NFD temperature at the lowest pressure drop have been determined. While the porosity approach was used to model the PCM melt front, a two-phase mixture was used to simulate NFD flow. It was discovered that the solar panel temperature and output temperature both increased considerably between t = 0 and t = 10 min before beginning to rise at varying rates, depending on the D_Pipe. The HTR coefficient increased over time, showing similar behavior to the panel temperature. The entire PCM melted within a short time for D_Pipes of 4 and 6 mm, while a large fraction of the PCM remained un-melted for a long time for a D_Pipe of 8 mm. An increase in D_Pipe, particularly from 4 to 6 mm, reduced the maximum and average panel temperatures, leading to a lower output flow temperature. Furthermore, the increased D_Pipe reduced the HTR coefficient, with the PCM remaining un-melted for a longer time under the panel.Deanship of Scientific Research at Najran UniversityPeer Reviewe

Investigating the Effect of Tube Diameter on the Performance of a Hybrid Photovoltaic–Thermal System Based on Phase Change Materials and Nanofluids

The finite element (FEM) approach is used in this study to model the laminar flow of an eco-friendly nanofluid (NF) within three pipes in a solar system. A solar panel and a supporting phase change material (PCM) that three pipelines flowed through made up the solar system. An organic, eco-friendly PCM was employed. Several fins were used on the pipes, and the NF temperature and panel temperature were measured at different flow rates. To model the NF flow, a two-phase mixture was used. As a direct consequence of the flow rate being raised by a factor of two, the maximum temperature of the panel dropped by 1.85 °C, and the average temperature dropped by 1.82 °C. As the flow rate increased, the temperature of the output flow dropped by up to 2 °C. At flow rates ranging from low to medium to high, the PCM melted completely in a short amount of time; however, at high flow rates, a portion of the PCM remained non-melted surrounding the pipes. An increase in the NF flow rate had a variable effect on the heat transfer (HTR) coefficient.The Deanship of Scientific Research at Najran UniversityPeer Reviewe

Numerical Analysis of the Effect of Nanoparticles Size and Shape on the Efficiency of a Micro Heatsink

In this paper, two novel micro heat sinks (MHSs) were designed and subjected to thermal analysis using a numerical method. The fluid used was Boehmite alumina–water nanofluid (NFs) with high volume fractions (VOFs). Studies were conducted to determine the influence of a variety of nanoparticle (NP) shapes, such as platelet brick, blade, cylinder, and Os. The heatsink (HS) was made of copper, and the NFs entered it through the middle and exited via four outlets at the side of the HS. The finite element method was used to simulate the NFs flow and heat transfer in the HSs. For this purpose, Multi Physics COMSOL software was used. The maximum and middle values of HS temperature (T-MAX and T-Mid), thermal resistance (TH-R), heat transfer coefficient (h), FOM, etc., were studied for different NP shapes, and with Reynolds numbers (Re) of 300, 1000, and 1700, and VOFs of 0, 3, and 6%. One of the important outcomes of this work was the better thermal efficiency of the HS with rectangular fins. Moreover, it was discovered that a rise in Re increased the heat transfer. In general, adding NPs with high VOFs to MHSs is not appropriate in terms of heat. The Os shape was the best NP shape, and the platelet shape was the worst NP shape for high NPVOF. When NPs were added to an MHS, the temperature of the MHS dropped by an average of 2.8 or 2.19 K, depending on the form of the pin-fins contained inside the MHS (circular or square). The addition of NPs in the MHS with circular and square pin-fins enhanced the pressure drop by 13.5% and 13.3%, respectively, when the Re = 1700.National Research Priorities funding programPeer Reviewe

Machine learning-based approach for modeling the nanofluid flow in a solar thermal panel in the presence of phase change materials

Considering the importance of environmental protection and renewable energy resources, particularly solar energy, the present study investigates the temperature control of a solar panel using a nanofluid (NFD) flow with eco-friendly nanoparticles (NPs) and a phase change material (PCM). The PCM was used under the solar panel, and the NFD flowed through pipes within the PCM. A number of straight fins (three fins) were exploited on the pipes, and the output flow temperature, heat transfer (HTR) coefficient, and melted PCM volume fraction were measured for different pipe diameters (D_Pipe) from 4 mm to 8 mm at various time points (from 0 to 100 min). Additionally, with the use of artificial intelligence and machine learning, the best conditions for obtaining the lowest panel temperature and the highest output NFD temperature at the lowest pressure drop have been determined. While the porosity approach was used to model the PCM melt front, a two-phase mixture was used to simulate NFD flow. It was discovered that the solar panel temperature and output temperature both increased considerably between t = 0 and t = 10 min before beginning to rise at varying rates, depending on the D_Pipe. The HTR coefficient increased over time, showing similar behavior to the panel temperature. The entire PCM melted within a short time for D_Pipes of 4 and 6 mm, while a large fraction of the PCM remained un-melted for a long time for a D_Pipe of 8 mm. An increase in D_Pipe, particularly from 4 to 6 mm, reduced the maximum and average panel temperatures, leading to a lower output flow temperature. Furthermore, the increased D_Pipe reduced the HTR coefficient, with the PCM remaining un-melted for a longer time under the panel.The Deanship of Scientific Research at Najran University.https://www.mdpi.com/journal/processesam2023Mechanical and Aeronautical Engineerin

Impact of quercetin encapsulation with added phytosterols on bilayer membrane and photothermal-alteration of novel mixed soy lecithin-based liposome

This study used highly lipophilic agents with an aim to increase the oxidant inhibitory activity and enhance photothermal stability of a novel mixed soy lecithin (ML)-based liposome by changing the composition of formulation within the membrane. Specifically, the development and optimization of the liposome intended for improving Trolox equivalent antioxidant capacity (TEAC) value and %TEAC loss was carried out by incorporating a natural antioxidant, quercetin (QU). In this context, a focus was set on QU encapsulation in ML-based liposomes and the concentration-dependent solubility of QU was investigated and calculated as encapsulation efficiency (EE). To explore the combined effects of the incorporation of plant sterols on the integrity and entrapment capacity of mixed phospholipid vesicles, conjugation of two types of phytosterols (PSs), namely β-sitosterol (βS) and stigmasterol (ST), to mixed membranes at different ratios was also performed. The EE measurement revealed that QU could be efficiently encapsulated in the stable ML-based liposome using 0.15 and 0.1 g/100 mL of βS and ST, respectively. The aforementioned liposome complex exhibited a considerable TEAC (197.23%) and enhanced TEAC loss (30.81%) when exposed to ultraviolet (UV) light (280–320 nm) over a 6 h duration. It appeared that the presence and type of PSs affect the membrane-integration characteristics as well as photodamage transformation of the ML-based liposome. The association of QU with either βS or ST in the formulation was justified by their synergistic effects on the enhancement of the EE of liposomes. Parallel to this, it was demonstrated that synergistic PS effects could be in effect in the maintenance of membrane order of the ML-based liposome. The findings presented in this study provided useful information for the development and production of stable QU-loaded ML-based liposomes for food and nutraceutical applications and could serve as a potential mixed lipids-based delivery system in the disease management using antioxidant therapy

Production of renewable diesel from Jatropha curcas oil via pyrolytic-deoxygenation over various multi-wall carbon nanotube-based catalysts

Jatropha curcas is a highly toxic plant that produces seed containing viscous oil with productivity (2 ton/ha), it grows in tropical and sub-tropical regions and offer greater adaptability to a wide range of climatic and soil conditions. Its oils have been noted as an important alternative to produce green diesel via deoxygenation reaction. This study, deoxygenation of jatropha curcas oil (JCO) was carried out over NiO–Fe2O3 and NiO–ZnO catalysts that supported onto multi-walled carbon nanotube (MWCNT). It had found that high Fe and Zn dosages were ineffective in deoxygenation and greatest activity was observed on NiO(20) Fe2O3(5)/MWCNT catalyst. Structure-activity correlations revealed that low metal loading, large density of weak + medium acidic sites and strong basic sites play key role in enhancing the catalytic activities and n-(C15+C17) selectivity. Comparing carbon nanostructures and carbon micron size supported NiO-Fe2O3 revealed that green diesel obtained from NiO–Fe2O3/MWCNT catalysed deoxygenation had the highest heating value and the lowest amounts of oxygen content. Thereby, it confirmed the importance of carbon nanostructure as the catalyst support in improving the diesel quality. Considering the high reusability of NiO-Fe2O3/MWCNT (6 consecutive runs) and superior green diesel properties (flash point, cloud properties and cetane index) demonstrated the NiO–Fe2O3/MWCNT catalyst offers great option in producing excellent properties of green diesel for energy sector

Production of green diesel from catalytic deoxygenation of chicken fat oil over a series binary metal oxide-supported MWCNTs

Deoxygenation processes that exploit milder reaction conditions under H2-free atmospheres appear environmentally and economically effective for the production of green diesel. Herein, green diesel was produced by catalytic deoxygenation of chicken fat oil (CFO) over oxides of binary metal pairs (Ni–Mg, Ni–Mn, Ni–Cu, Ni–Ce) supported on multi-walled carbon nanotubes (MWCNTs). The presence of Mg and Mn with Ni afforded greater deoxygenation activity, with hydrocarbon yields of >75% and n-(C15 + C17) selectivity of >81%, indicating that decarboxylation/decarbonylation (deCOx) of CFO is favoured by the existence of high amount of lower strength strong acidic sites along with noticeable strongly basic sites. Based on a series of studies of different Mg and Mn dosages (5–20 wt%), the oxygen free-rich diesel-range hydrocarbons produced efficiently by Ni10–Mg15/MWCNT and Ni10–Mn5/MWCNT catalysts yielded >84% of hydrocarbons, with n-(C15 + C17) selectivity of >85%. The heating value of the green diesel obtained complied with the ultra-low sulphur diesel standard

The detection of glycidyl ester in edible palm-based cooking oil using FTIR-chemometrics and 1H NMR analysis

Glycidyl ester (GE) is a process contaminant formed during the palm oil refining process. In this study, 156 spectra of palm-based cooking oilwere recorded by Fourier transform infrared (FTIR) spectroscopy and resulting data were processed using chemometrics approach. The relationship between spectrum data and measured data of GE content was established using Cubist, Random Forest (RF), average neural network (avNNET), and artificial neural network (nnet) model. Then, a consensus regression model was established using a fusion of those four models. GE contents measured by gas chromatography-mass spectrometer (GC-MS) were between 1.338 and 18.362 mg/kg with mean value of 6.880 ± 3.767 mg/kg and median value of 6.480 mg/kg. In this study, FTIR spectrum served as data input and calibrated using measurements from GC-MS. NMR was then applied to verify the present and structural information of GE. Prediction results of GE using the consensus model showed -high coefficient of determination (R2) value of 0.79. The contribution (in percentage) of each member model from highest to the lowest was in order Cubist > RF > avNNET > nnet. Further confirmation of the presence of GE in samples were performed using 1H NMR spectroscopy. Comprehensive analyses based on FTIR chemometrics and 1H NMR spectroscopy successfully determined GE in palm-based cooking oil

Green photosensitisers for the degradation of selected pesticides of high risk in most susceptible food: a safer approach

Pesticides are the leading defence against pests, but their unsafe use reciprocates the pesticide residues in highly susceptible food and is becoming a serious risk for human health. In this study, mint extract and riboflavin were tested as photosensitisers in combination with light irradiation of different frequencies, employed for various time intervals to improve the photo-degradation of deltamethrin (DM) and lambda cyhalothrin (λ-CHT) in cauliflower. Different source of light was studied, either in ultraviolet range (UV-C, 254 nm or UV-A, 320–380 nm) or sunlight simulator (> 380–800 nm). The degradation of the pesticides varied depending on the type of photosensitiser and light source. Photo-degradation of the DM and λ-CHT was enhanced by applying the mint extracts and riboflavin and a more significant degradation was achieved with UV-C than with either UV-A or sunlight, reaching a maximum decrement of the concentration by 67–76%. The light treatments did not significantly affect the in-vitro antioxidant activity of the natural antioxidants in cauliflower. A calculated dietary risk assessment revealed that obvious dietary health hazards of DM and λ-CHT pesticides when sprayed on cauliflower for pest control. The use of green chemical photosensitisers (mint extract and riboflavin) in combination with UV light irradiation represents a novel, sustainable, and safe approach to pesticide reduction in produce