Recent Trends in Chemical and Material Sciences Vol. 1

Electrodeposited Cu₂O/AZO photovoltaic (PV) devices are promising low-cost solar cells. In this research, both layers of Cu₂O and AZO heterojunction architectures are studied as a function of AZO target-Cu₂O substrate distance during the sputtering process. The Cu₂O/AZO PV device has been constructed by electrodeposition of a <111>-p-Cu₂O layer on an Au (111)/Si wafer substrate followed by stacking the AZO layer using a sputtering technique. The Cu₂O/AZO PV device showed a photovoltaic performance under AM1.5 illumination, and the performance changed depending on the target-substrate distance. It is shown that an increase in target-substrate distance during stacking the AZO layer by sputtering mitigated the damage at the Cu₂O/AZO interface. As a result, we were able to improve the Voc and power conversion efficiency from 0.16 V and 0.46 % to 0.30 V and 0.64%, respectively.

Duplex stainless steels (DSS) exhibit attractive combination of austenitic and ferritic properties and have been extensively used in various industries such as petrochemical, pulp and paper etc. They demonstrate better corrosion resistance, especially chloride stress corrosion and chloride pitting corrosion, and exhibit higher strength than standard austenitic stainless steels. For these reasons, they are excellent candidate for offshore oil and gas industry. In the present study, stress corrosion behaviour of duplex stainless steel in 3.5% sodium chloride solution, has been investigated by weight loss measurements, electrochemical corrosion testing and slow strain rate test (SSRT). Weight loss data showed no significant corrosion after 1700 hours. Electrochemical polarization test in 3.5% NaCl solution exhibited a uniform corrosion rate of 0.008 mpy showing passivity in the range of 735–950 mV Vs SSC. A comparison of the slow strain rate test for duplex stainless steel in 3.5% NaCl solution also showed a similar stress-strain behaviour. In contrast, the stress-strain behaviour of mild steel showed a loss of about 25% elongation. The excellent corrosion and especially the pitting resistance was considered to be responsible for maintaining good ductility in DSS.

Based on innovation and competitive market for food industry, there are several food products which have been designed to attract customer. Since there is USD 39,431 millions of chocolate sales in 2018, USA [1], chocolate product shapes have been developed based on manufacturing process.This paper presents a review process of a machine design of chocolate extrusion based co-rotating twin screw extruder. A property of suitable chocolate for extruder was established. The pros and cons of machine extruder for food processing including, a screw extruder design were exposed. Since there were problems in the chocolate extruder, the process parameters such as barrel temperatures, feed rate, screw speed, motor load and melt pressure were established. These parameters would be applied to design screw extruder for chocolate processing.

Two main points of the objectives to design software systems (SS) have been considered: achieving proper functioning of the SS with consistent results, and the possibility to obtain reliable assessments of the Software System quality depending on the initial requirements. A cognitive-contextual design strategy has been proposed that can significantly improve the perception of actual elements of the design task by creating a context with selected formalized conditions, and enhance cognitive coherence of the project elements throughout the Software System lifecycle.

The paper presents a six-degree of freedom mathematical model of a light sport aircraft and analytically reveals aircraft dynamic response both longitudinal and lateral-directional stability. The model composes of both the kinematics equations of motion and the kinetics equations of aerodynamic forces and moments, known as the aerodynamic model equations. Simulation results show responses of the perturbed dynamic system at trim condition, which indicates dynamic stability of both short-period pitching oscillation and phugoid in longitudinal axes. The spiral, roll subsidence, and dutch roll modes in lateral-directional axes are also dynamic stable as well. These are essential to understand and evaluate the dynamic behavior, stability, safety, and other aspects of the designed aircraft through a mathematical model before conducting an operational flight test.  

In this work, the nanotechnology procedure was utilized to improve both the adhesion force and surface properties of graphene oxide (GO) films. GO has been obtained in a powder form by oxidation purified graphite using the modified Hummer’s technique. Different films of GO nanoparticles (NPs) were deposited using several types of solvents distilled water, acetone, ethanol, dimethylformamide (DMF) or ethylene glycol. The examination of structural and optical properties of GO films was studied by XRD and UV–vis absorption spectroscopy. Moreover, electrical properties, surface roughness, contact angle, adhesion force, wetting energy and spreading coefficient were investigated. It was observed that the properties of the prepared films are influenced by the solvent type. The electrical resistivity of films is highly dependent on the solvent type which exhibited the lowest value with distilled water. Furthermore, GO film synthesized with distilled water has the best values of adhesion force and average surface roughness (Ra) 143.4 mN/m and ~ 7.83 µm, respectively. These results are mostly attributed to hydrophilic cites and GO NPs agglomeration in the surface of films and the effects of their size leading to an expansion in the surface roughness.

Highly sensitive spectrophotometric and gas chromatographic methods were developed for the determination of chloropyrifos. Alkaline hydrolysis of chloropyrifos to 1,2,4-trichloropyridine was the basis followed by coupling with congored in presence of nitric acid. The absorption maxima of blue color formed at 800-900C was formed at 605nm.Beer’s law was obeyed in the range of 0.5-5.7 ppm. The standard deviation was found to be ± 0.005.The method was free from other pesticide interferences. The method was applied to various fruits and vegetables procured at various agricultural fields at sabbavaram area, Visakhapatnam, India and found satisfactory. Keeping in view of extensive use of pesticides on fruits and vegetables damaging the ecological balance. Determination of pesticide residue in The various vegetables collected are cauliflower, potato, spinach, and fruits suchas pinkapple, grapes etc were analysed by using Gas –chromatography with electron capture detector (GC-ECD). GC-ECD has great potential for determining organochlorine pesticides in food extracts at low levels.  Residues were extracted with hexane, dichloromethane and ethyl acetate (1:1% V/V).Clean up procedure was carried by applying solid phase extraction column. The recoveries of chloropyrifos pesticide in fruits and vegetables selected were in the range of 80 to 98% fortified at 0.5 mg/Kg. Some grape samples showed above the limit of quantification.

The mechanical qualities of fiberglass-reinforced Polymer Composite Materials (PCM) are critical for fibre boat construction. Mechanical testing is very important for fiber boat. The Impact test was used to determine the mechanical properties of this study. Each test was carried out on different amounts of fibreglass lamination CSM 300, CSM 450 and WR 600, as well as different weight percentages  of 99.5% -0.5%, 99% -1%, 98.5% -1 , 5%, 98% -2% and 97.5% -2.5%. The results reveal that the more laminate used, the higher the impact strength (413,712 MPa), and the higher the percentage hardener used, the higher the impact strength 2.0 wt.- percent (416,487 MPa).

The aim of this paper is to review the literatures on technological innovation of industries in relating to the growth of the economy in past decade. The data and ideas on this paper come primarily from review articles relating to the economic development of the nations. The level of success in innovation in the various technology differs among countries because of the different national background and cultures. Innovation technology has always played a critical role for the long-term survival of organizations. This paper serves as a description to the researchers in predicting for the next future study to improve the better quality and standard of living. Innovation also plays an important role in constructing the economy, in expanding and sustaining the high performance of companies, in improving the standard of living and in creating a better quality of life.

The volume thermal expansion of nanomaterials under the influence of temperature has been studied using a new integral form of equation of state (IFEOS). A wide variety of nanomaterials such as fullerene (C60), 20 nm-Ni, 15 nm-(80Ni+20Fe), n-ZnO, n-TiO₂ and n-NiO has been considered to analyse the influence of temperature on them. The acquired results were compared to existing experimental data as well as other theoretical approaches. The validity of the newly established integral form of equation of state (IFEOS) for nanomaterials is supported by excellent agreement between theory and current experimental data.

A comparative study of the results of Spark-Plasma Sintering (SPS) of two-types of aluminum oxide nanopowders, obtained by the method of conductor explosion and plasma synthesis. When the parameters of both powders are similar (spherical form of the particles, size, phase composition) as well as SPS modes the properties of the resulting compacts are significantly different both in mechanical properties and microstructure. The reason of differences in the properties of the obtained compacts is in technological impurities in powders, obtained by different methods. Artificial addition of impurities, contained in the nanopowder, obtained by electro explosion of conductor, into the powder, made by synthesis in plasma and not containing these impurities, allowed to reveal their effect on the formation of the microstructure and properties of the sintered by SPS method sample.

Using first-principles approaches, the absorption spectrum of dichloride-bis(5,7-dichloroquinolin-8-olato)tin(IV) with the molecular formula Q₂SnCl₂ is calculated and compared with experimental data.
The single excited molecular orbitals (SEMO) from the ground state to the excited states of the molecule are used to calculate the energy correction terms for the excitation energies. The contributions of the Columbic interaction between an excited electron and the remaining hole in the absorption spectrum during the optical excitation process can be determined using this method. The density functional theory (DFT) is used to compute the MO energy difference and MO wave functions, as well as the SEMO energy contribution. The results show that using the SEMO's contributions in energy corrections improves the theoretical optical absorption spectrum greatly. The calculations are based on DFT, and the essential parameters and integrals for SEMO computation are acquired using this method. Due to its ability to describe MOs for any excitation energy and lower computational cost, this method is chosen over alternative ab-initio methods for calculating excited states. For the first time, the method is used to calculate the energy of transitions and specifies the electronic transition between MOs, particularly in absorption machinery of the OLED. The theoretical spectrum is closer to the experimental spectrum when the electron-hole interaction is taken into account in the optical mechanism of absorption in the molecule. As a result, the electron-hole interaction, or the interaction between the excited electron and the remaining hole, plays a critical role in the absorption mechanism that cannot be ignored.

Failure of structures may be analyzed based on strength criterion or fracture mechanics criterion. Strength criterion deals with material resistance beyond the critical conditions such as yield, and ultimate strength. In fracture mechanics the critical condition is defined by toughness which can be stress intensity factor (K) or fracture energy (G). This study explores the critical point during loading up to the limit of elasticity based on linear elastic fracture mechanics – LEFM. However, nonlinearity frequently appears due to the existence of a relatively large fracture process zone – FPZ located at the crack-tip. The assumption of LEFM in quasi – brittle material such as concrete is therefore limited to large size structures only. The well known approach to obtain the fracture energy G_f for infinite large structures is size effect law – SEL. G_f is defined as the specific energy, i. e. energy per unit crack plane area. This is elastic energy which is linear. The objective of this study is to answer one question: Does reinforcement work only during composite action between the reinforcement with concrete or does it work before?. A research was conducted following the principles of work-of-fracture – WOR using the RILEM Specification Test Method. Three-point-bend beam specimens were made of normal concrete, subjected to monotonic load P, until they failed. P–u relationship prevails the real work. The elastic fracture energy based on WOR that is \(G {R \over F}_{-el}\) was found by divided the area under P–u curve of elastic range with ligament. The result is, \(G {R \over F}_{-el}\) equal to 397.87 N/m for beam A1 (bending failure l/h=5.5), 133.6 N/m for beam B1 (shear failure, l/h=5.0). 101.93 N/m for beam B2 (shear failure, l/h=5.0), 153.75 N/m for beam B3 (shear failure, l/h=5.0). The greater value \(G {R \over F}_{-el}\) comparing to G_f indictes that reinforcement roles in increasing elastic fracture energy, not only in plastic fracture energy.

Modal was first introduced by Lenzing AG Company of Austria who trade named the fabrics identity. Modal is very soft, shiny in nature and silk feel than mercerized cotton with the ability to absorb up to 50% more water than cotton. Fabric made from modal drape well and do not pile like cotton. In this study, modal fabrics (woven and knitted) are selected and conventionally pretreated and subjected with 98% formic acid in different concentrations. The formic acid treated modal fabrics were then undergone for different testings. These treatments on modal fabrics were correspondingly compared with those of cotton for its effectiveness. Also compared with the no formic acid treated modal fabric and cotton fabric respectively.