Advanced Materials Research Vol. 979

Abstract: The pineapple peel cellulose can be convert to carboxymethyl cellulose (CMC) by etherification. The pure cellulose from pineapple can be prepared by refluxing of pineapple peel powder with 0.5 M HCl and 1 M NaOH solution at 90°C for 1 h and 2 h, respectively. Then, the solid material was bleached with calcium hypochlorite. The pure cellulose was soaked in mixed solution between isopropyl alcohol and NaOH for 12 h. After that, it was reacted with cholroacetic acid at 55°C for 6 h. The optimum condition for carboxymethylation was cellulose 5 g, cholroacetic acid 13.0 g and 40%w/v NaOH 50 mL. The optimised product had a DS of 0.50 and used as constituent in bioplastic. The application of pineapple peel bioplastic probably is green packaging of dehydrated materials.

Abstract: Titanium dioxide (TiO₂) nanothin films were deposited on unheated substrate, the glass slide and Si-wafer, by DC reactive magnetron sputtering with different substrate-target distance (d_st), in range of 8 to 14 cm. The structural, surface morphology and transmittance spectrum of TiO₂ thin films were characterized by grazing-incidence X-ray diffraction (GI-XRD), atomic force microscopy (AFM) and spectrophotometer, respectively. XRD results show that as-deposited TiO₂ films with short substrate-target distance have only anatase crystal structure corresponding to the anatase in (101) and (200) plane, and turn to be amorphous with long substrate-target distance. The thickness and roughness varied from 50 nm to 142 nm and 1.6 nm to 3.5 nm, respectively. The as-deposited TiO₂ films exhibited high visible transmittance. The optical constants of the films, refractive index (n) and extinction coefficient (k), were calculated by Swanepoel method, at 550 nm, was about 2.43 - 2.76 and 0.082 - 0.187, respectively. The energy band gap (E_g) of the as-deposited TiO₂ films in the range of 3.20 - 3.25 was observed.

Abstract: Zirconium oxide (ZrO₂) thin films were deposited on Si-wafer and glass slide substrates by reactive DC unbalanced magnetron sputtering at different deposition times. A pure metallic zirconium target (99.97%) was sputtered in a gas mixture of argon and oxygen. The crystal structure was characterized by GI-XRD (grazing-incidence X-ray diffraction) whereas surface morphologies and films thickness were evaluated by AFM (atomic force microscopy). The transmittance spectrum was measured by spectrophotometer. The optical constants of the as-deposited films were calculated by Swanepoel method. It was found that the ZrO₂ films deposited on silicon substrates showed a highly monoclinic phase (-1 1 1). The as-deposited films showed high transmittance in visible range. The thickness and roughness varied from 155 nm to 502 nm and 3.1 nm to 3.6 nm, respectively, with increasing of deposition times. The optical constants namely refractive index (n) and extinction coefficient (k), at 550 nm, was about 1.9 - 2.1 and 0.0003 - 0.0009, respectively. In addition, the energy band gap (E_g) of the as-deposited film was approximately 4.17 eV.

Abstract: Carbon nanopowder mixed with carbon ink was used as a working screen-printed electrode. This electrode consists of carbon nanopowder working electrode, carbon counter electrode, and silver/silver chloride reference electrode. The electrochemical behavior of ascorbic acid has been studied by cyclic voltammetry and differential pulse voltammetry with screen-printed carbon nanopowder electrode. The propose electrode will enhanced the sensitivity for antioxidance determination because increasing of the surface area of the working electrode. The voltammetric sensor offers several advantages to both the green chemistry and eco-friendly. The method was successfully employed with 2 microliter of the working solution dropped on the electrode surface. A linear concentration, limit of quantitation and limit of detection was sufficient for the ascorbic acid determination in the vitamin C tablet. The results obtained for the sample juices demonstrated that the powerful of the method.

Abstract: The dyeing of cotton fabrics using mulberry leaves (Morus alba L.) as a natural dye has been studied in both conventional heating and ultrasonic techniques. The extractability of Mulberry leaves dye from natural origin using power ultrasonic was also evaluated in comparison with conventional heating. The mulberry leaves extract to provided brown-green to green color, depending on the pH concentration. The results of dye extraction indicate that power ultrasonic is rather effective than conventional heating at low temperature and short time. The effects of dye bath pH, dyeing time, dyeing temperature and mordants were studied and the colorimetric parameters L*, a*, b* of dyed fabrics with ultrasonic and conventional techniques were compared.

Abstract: In this paper, we introduce a new theoretical scheme for evaluating the performance of backoff algorithms focusing on multiple types of wall and floor material such as: concrete, wood, glass and brick. The proposed scheme is an extension and combination between Bianchi and Multi-wall-floor model, by applying discrete Markov chain theorem. In addition, we also propose two backoff algorithms which can improve the saturated throughput efficiency of IEEE802.11 wireless local area network (WLAN). The proposed backoff algorithms are called Binary Exponential Increment Half Decrement backoff algorithm (BEIHD), and Half Binary Exponential Increment Double Decrement backoff algorithm (HBEIDD). The numerical results show that significant improvement saturated throughput of HBEIDD backoff algorithm operates well for plywood wall and wood floor materials in indoor environment.

Abstract: The bismuth borophosphate glass matrix doped with Nd₂O₃ have been prepared by conventional melt quenching method with the molar compositions of 25Bi₂O₃ : 5B₂O₃ : (70-x)P₂O₅ : xNd₂O₃ (where x = 0.2, 0.4, 0.6, 0.8 and 1.0 mol%). The density, molar volume, optical absorption and upconversion luminescnece spectra were studied. It can be seen that the density is not depend on Nd₂O₃ concentration. The molar volume is tending to be decreased with increasing of Nd₂O₃ due to the decrease in the bond length or interatomic spacing between the atoms. Ten absorption bands at 427, 471, 510, 525, 580 , 622, 682, 743, 802 and 873 nm are observed, which could be ascribed to Nd³⁺ transitions from the ⁴I_9/2 ground state to ²P_1/2, ²G_9/2, ⁴G_9/2, ⁴G_7/2, ⁴G_5/2 + ²G_7/2, ²H_11/2, ⁴F_9/2, ⁴F_7/2 + ⁴S_3/2, ⁴F_5/2 + ⁴H_9/2 and ⁴F_3/2 levels. The upconversion luminescence band at 394 nm was observed and the highest emission intensity was obtained at 0.8 mol% of Nd₂O₃.

Abstract: The total mass attenuation coefficient (μ/ρ, cm² g^-1) of gamma-ray for building materials containing with Lead Carbonate (PbCO₃) have been studied. The raw building material have cement, sand and stone in the ratio 1 : 2 : 4. The raw material was mixed with 30% of PbCO₃ to be used as the sample material. The mass attenuation coefficient of the raw material has been calculated by theoretical approach using WinXCom program for the photon energy band from 1 keV to 100 GeV. The composition of sample material was analyzed by energy dispersive X-ray fluorescence spectrometer (EDXRF). The variations of mass attenuation coefficient are shown graphically and compared with that of standard shielding concretes. It was found that the sample building material has higher value of mass attenuation coefficient than standard shielding concretes at energy zone above 2–7 keV, 90–800 keV and 5 MeV–100 GeV.

Abstract: The aim of this paper is comparative study of physical and optical properties of glasses from SiO₂ and Napier ash (Pennisetum purpureum ash (PA)). PA was selected from biomass power plant. Selected ash was sintered at different temperature (500, 800 and 1000 °C). The glasses containing in formula 55SiO₂ : 20Na₂O : 1.0Al₂O₃ : 13B₂O₃ : 6.3CaO : 0.2Sb₂O₃ : 4.5BaO. It has been found that the density and refractive index of PA glasses increases with a increasing sintering temperature. However, SiO₂ glass has density and refractive index more than PA glasses every different sintering temperature. The spectra of PA glass are shown cut-off wavelength around 330 nm at all glass samples.

Abstract: In this work, total mass attenuation coefficients and effective atomic numbers of a series of three host glasses with different chemical composition, 65R_mO_n : 10CaO : 25Na₂O mol% (where R_mO_n are B₂O₃, SiO₂ and P₂O₅, respectively) have been studied as a function of photon energy. The total mass attenuation coefficient values were taken from WinXCom program, were used to evaluate the effective atomic numbers in the energy range from 1 keV to 100 GeV. The obtained results for all samples are compared and discussed.