Characterization of titania thin films grown by dip-coating technique

A dip-coating technique was employed to prepare anatase phase of titania thin films. Fluorine doped tin oxide substrates were used to prepare titania thin films. The samples were annealed at 550 °C for 18 h. X-ray diffraction results revealed the amorphous and anatase phases of TiO₂ for as-synthesized and annealed samples, respectively. The crystallite size of anatase TiO₂ thin films was almost 25 nm for annealed samples. UV–visible confirmed the energy band gap 3.86 and 3.64 eV for as-prepared and calcinated titania thin films. The reduction in the energy band gap could be due to the change in crystallization and agglomeration of small grains after calcination. The morphology of the prepared films was investigated by field emission scanning electron microscopy which demonstrated the agglomeration of spherical particles of TiO₂ with average particle size of about 30 nm. The molecular properties (chemical bonding) of the samples were investigated by means of Fourier Transform Infrared (FTIR) spectroscopy. FTIR analysis exhibited the formation of titania, functional group OH, hydroxyl stretching vibrations of the C–OH groups, bending vibration mode of H–O–H, alkyl C–H stretch, stretching band of Ti–OH, CN asymmetric band stretching, and C=O saturated aldehyde.     

Energy use efficiency and economical analysis of almond production: a case study in Chaharmahal-Va-Bakhtiari province,Iran

The aim of this study was to analyse input–output energy and economical assessment of almond production in three age groups of orchards (group I 6–10, group II 11–15 and group III 16–20 years old) in Chahrmahal-Va-Bakhtiari province, Iran. Data for almond production were collected by administering questionnaire in face-to-face interviews from the orchards selected based on random sampling method during a 3-year period. The results showed that 57,027.13, 60,341.14 and 61,640.43 MJ ha^?1 energy was consumed by group I, group II and group III, respectively. The most energy input was consumed by electricity, followed by chemical fertilizer. Energy indices were calculated, and the results revealed that energy efficiency was 0.62, 1.12 and 0.81 in the triple groups of orchards, respectively. Economical assessment showed that total production cost of almond in group I, II and III was $4547.54, $5799.26 and $5687.05 ha^?1, respectively. In all orchard groups, the shares of variable and fixed production costs found to be same nearly. Net return for almond production was $14,516.22, $30,735.19 and $21,395.57ha^?1, respectively. According to the research results, it was concluded that although almond production in the study region was not an efficient process in terms of energy consumption, it was a profitable agricultural operation.     

Infrared thin layer drying of saffron (Crocus sativus L.) stigmas: Mass transfer parameters and quality assessment

Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativus L. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures(60,70, …, 110 °C). It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were determined by using the Dincer and Dost model. The diffusivity values varied from1.1103 × 10~(-10)m~2·s~(-1)to 4.1397 × 10~(-10)m~2·s~(-1) and mass transfer coefficient varied in the range of 2.6433 × 10~(-7)–8.7203 × 10~(-7)m·s~(-1). The activation energy was obtained to be 27.86 k J·mol~(-1). The quality assessment results showed that the total crocin content increased, when the temperature increased up to90 °C but, in higher temperatures, the amount of crocin decreased slightly. The total safranal content of the samples decreased slightly when drying temperature increased from 60 °C to 70 °C and then continuously increased up to 110 °C. Also, the amount of picrocrocin increased from 83.1 to 93.3 as the drying temperature increased from 60 °C to 100 °C.     

Study on Wear Model and Adhesive Wear Mechanism of Brass under Boundary Lubrication

Protection of Metals and Physical Chemistry of Surfaces - The tribological tests of brass and steel are carried out on an in-situ tribometer. The Stribeck curve illustrates that the roughness and...     

Synthesis of Silver Nanoparticles and Exhaustion on Cotton Fabric Simultaneously Using Laser Ablation Method

ABSTRACT

In this experimental research, the silver nanoparticles were synthesized on cotton fabric using laser ablation method in the same bath. Also the effects of the size of silver nanoparticles (NPs) on the structural and antibacterial properties of silver NP-coated cotton fabric have been investigated experimentally. A pulsed laser beam was used for synthesis of Ag NPs on cotton fabric. Pulses of a Q-switched Nd:YAG laser of 1064 nm wavelengths at 7 ns pulse width and different fluencies was employed to irradiate the Ag target in deionized water in the presence of cotton fabric. Four samples were prepared using different laser fluencies. The amount, size, morphology, and structure of produced NPs were studied using their spectrum in the range of UV to IR, and scanning electron microscopy methods. Fabrics were polluted by gram-positive Staphylococcus aureus bacteria. The colony counting method was used to investigate the antibacterial activity of prepared cotton samples. Results show that laser ablation for synthesis of Ag nanoparticles on cotton fabric is an inexpensive fast method for producing antibacterial fabrics.     

Soluble soybean polysaccharide/TiO2 nanocomposites: Biological activity,release behavior,biodegradability, and biosafety

This study aimed to produce and characterize eco-friendly SSPS nanocomposites incorporated with various concentrations of TiO₂ nanoparticles (NPs) (1%, 3%, and 7%). The antimicrobial activity of the nanocomposite films against five strains of pathogenic bacteria was examined. Salmonella typhi PTCC 1609 was the most sensitive species to TiO₂ NPs at concentrations equal to the synthetic antibiotic. The migration of TiO₂ to ethanol and acetic acid, as two food simulants increased when the initial nano-TiO₂ content increased. The release profiles for TiO₂ in two simulants of ethanol and acetic acid indicated a non-Fickian release, and the release kinetics were concentration-dependent. SSPS/TiO₂ nanocomposites degraded easily and thus have the potential to be applied as an eco-friendly packaging system. Oral administration of doses of 1, 12.5, 25, 50, and 75 mg/kg TiO₂ revealed that the dose of 50 and 75 mg/kg increased malondialdehyde (p < .001) concentration in the liver tissue. In addition, it decreased glutathione (p < .001) concentration in the liver tissue.     

Effective adsorption of ciprofloxacin antibiotic using powdered activated carbon magnetized by iron(III) oxide magnetic nanoparticles

Journal of Porous Materials - In the present work, the adsorption performance of powdered activated carbon magnetized by iron(III) oxide magnetic nanoparticles (PAC@Fe3O4-MN) for the removal of...     

A broadband slant polarized cavity backed microstrip‐fed wide‐slot antenna array

This article deals with the design of a broadband cavity‐backed microstrip‐fed wide‐slot antenna array for L‐band applications. For verification purpose, a sample 1 × 4‐element antenna array has been designed, manufactured and tested. Experimental results have shown satisfactory agreement with the simulation. The proposed antenna array exhibits a measured impedance bandwidth of 1.4 GHz (90%) with frequency of 0.85 to 2.25 GHz and the gain is higher than 11 dBi. The designed antenna has small size and low weight and can be fabricated using a low‐cost fabrication process for easy integration with RF circuits and microwave components. This work is useful for some radar applications and radio frequency identification systems.     

Asymmetric Trilayer All-Polymer Dielectric Composites with Simultaneous High Efficiency and High Energy Density: A Novel Design Targeting Advanced Energy Storage Capacitors

Polymeric dielectrics have attracted intensive attention worldwide because of their huge potential for advanced energy storage capacitors. Thus far, various effective strategies have been developed to improve the inherent low energy densities of polymer dielectrics. However, enhanced energy density is always accompanied by suppressed discharge efficiency, which is detrimental to practical applications and deserves considerable concern. Targeting at achieving simultaneous high energy density and high discharge efficiency, the unique design of asymmetric all-polymer trilayer composite consisting of a transition layer sandwiched by a linear dielectric layer and a nonlinear dielectric layer is herein reported. It is demonstrated that the nonlinear dielectric layer offers high energy density, while the linear dielectric layer provides high discharge efficiency. Especially, the transition layer can effectively homogenize the electric field distribution, resulting in greatly elevated breakdown strength and improved energy density. In particular, a high efficiency of 89.9% along with a high energy density of 12.15 J cm⁻³ are concurrently obtained. The asymmetric trilayer all-polymer design strategy represents a new way to achieve high-performance dielectric energy storage materials.     

Implementation of meshless LBIE method to the 2D non‐linear SG problem

In this paper the meshless local boundary integral equation (LBIE) method for numerically solving the non‐linear two‐dimensional sine‐Gordon (SG) equation is developed. The method is based on the LBIE with moving least‐squares (MLS) approximation. For the MLS, nodal points spread over the analyzed domain are utilized to approximate the interior and boundary variables. The approximation functions are constructed entirely using a set of scattered nodes, and no element or connectivity of the nodes is needed for either the interpolation or the integration purposes. A time‐stepping method is employed to deal with the time derivative and a simple predictor–corrector scheme is performed to eliminate the non‐linearity. A brief discussion is outlined for numerical integrations in the proposed algorithm. Some examples involving line and ring solitons are demonstrated and the conservation of energy in undamped SG equation is investigated. The final numerical results confirm the ability of method to deal with the unsteady non‐linear problems in large domains. Copyright © 2009 John Wiley & Sons, Ltd.