Sliding mode tracking control of mobile robots with approach angle in cartesian coordinates

International Journal of Control, Automation and Systems - In this paper, we propose a method for designing the sliding mode based tracking control of a mobile robot in Cartesian coordinates with...     

Experimental characterisation of Polyethylene Terephthalate (PET) bottle Eco-bricks

This paper addresses the issue of recycling waste plastic by considering the feasibility of use of Eco-bricks for constructional purposes. The Eco-bricks are formed by packing plastic within Polyethylene Terephthalate (PET) bottles. Guidelines were provided for the construction of Eco-bricks. Experiments were carried out to characterise some of the properties of these bricks. Compression test, sound insulation assessment and light transmission were considered in this regard and compared with traditional construction materials and conditions. Possible applications of Eco-bricks were discussed. The paper presents the first attempt to characterise these bricks and the results encourage future use of them to a significantly wider extent and for various purposes.     

Fabrication and characterization of gum Arabic bonded Rhizophora spp. particleboards

Gum Arabic (GA) was used as a binder for the fabrication of Rhizophora spp. particleboards. The physical and mechanical properties of the bioadhesive bonded particleboards, including moisture content, internal bond (IB) strength, thickness swelling (TS), water absorption (WA) and field-emission scanning electron microscopy (FESEM) were used to characterize the manufactured particleboards. Three different particle sizes of the Rhizophora spp. with four adhesive levels were utilized. Results revealed that the addition of GA into the particleboards noticeably improved panel overall properties. The GA bonded particleboards resulted in smoother surfaces, more rigid texture and better internal bonding strength compared to binderless particleboards made without using any adhesive. All specimens had internal bond strength of more than the minimum requirement of the Japanese Industrial Standard JIS A-5908 Type-8 of 0.15 N/mm² and were noticed to increase by increasing the adhesive level. However the GA bonded particleboards had higher percentage of WA and the TS compared with the binderless boards. Microscopic study also revealed that particleboards bonded with the gum had better contact compared to the binderless boards. Based on these results, it could be concluded that gum Arabic is an effective natural substance that could be added to manufacture particleboards to improve some of panels’ physical and mechanical properties.     

Phthalonitrile based charge transfer type host for yellow phosphorescent organic light-emitting diodes

An phthalonitrile based 3,3''-di(9H-carbazol-9-yl)-[1,1':2′,1''-terphenyl]-4′,5′-dicarbonitrile (IPNCz) was explored as a charge transfer type host of a yellow emitting bis(4-phenyl-thieno[3,2-c]pyridinato-C2,N)(acetylacetonato)iridium(III) (PO-01) dopant. The phthalonitrile unit was an electron deficient unit and 9-phenylcarbazole was an electron rich unit of the IPNCz host. The phthalonitrile unit combined with the phenylcarbazole unit allowed strong charge transfer character by the donor-acceptor structure, delivering good thermal stability, bipolar carrier transport and proper triplet energy. Therefore, the IPNCz host assisted low driving voltage and high quantum efficiency close to 25% in the yellow phosphorescent device.     

Density functional perturbation theory calculations of vibrational and thermodynamic properties of Zn1−xBexO alloys

The elastic, phonon and thermodynamic properties of Zn_1−xBe_xO alloy are investigated by performing density functional theory (DFT) and density functional perturbation theory (DFPT) calculations. The calculated lattice parameters decreases with the increase of Be content that is in good agreement with the available theoretical and experimental data. The effect of Be composition on elastic constants was investigated for Zn_1−xBe_xO alloys. Phonon dispersion curves show that Zn_1−xBe_xO are dynamically stable. Thermodynamic properties, including Helmholtz free energy, enthalpy, entropy and heat capacity, were evaluated under quasi-harmonic approximation using the calculated phonon density of states. Finally, the results show that Zn_1−xBe_xO alloys with lower Be content are more thermodynamically stable. The agreement between the present results and the known data that are available only for ZnO and BeO is generally satisfactory.     

Evolution of morphology and magnetism of Ho(Fe0.5Co0.5)3 intermetallic nanopowders synthesized by HEBM

The morphology and magnetic properties of bulk and ball – milled Ho(Fe_0.5Co_0.5)₃ intermetallic compounds were studied. The influence of the high energy ball – milling (HEBM) duration for the final size of particles and crystallites was confirmed by a variety of complementary measurement methods. The presence of the main PuNi₃ type of crystal phase was confirmed for crystalline and as – milled samples. The emergence of a partly amorphous phase was confirmed at the end of pulverization (t = 80 h). The synthesis of nanostructured flakes with a thickness of less than 100 nm after applying HEBM for various time periods was confirmed. Additionally, the formation of agglomerates for the prolonged pulverization was evidenced. The non – linear variation of magnetic parameters across milling was observed. Furthermore, a slight exchange bias and deformation of hysteresis loops for as – milled powders was noticed. A quantitative analysis of XPS spectra at the end of grinding process indicates the probable coating of flakes by Fe/Co oxides the amount of which varies over ion etching.     

Effects of exciton blocking layer and cathode electrode work function on the performance of polymer solar cells

In this study the effects of some important processing and post-processing treatments on the performance of poly(3-hexylthiophene-2,5-diyl) (P3HT):[6,6]-phenyl-C₆₁-butyric acid methyl ester ([60]PCBM) solar cells were investigated. These parameters included the active layer film formation period, thermal annealing, electrical treatment, cathode work function modification, and exciton blocking layer type and thickness. Polymer bulk heterojunction solar cells having a glass/indium tin oxide (ITO)/poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)/P3HT:PCBM/(Ca or LiF)/Al structure were fabricated. The morphology of the active layer was investigated using atomic force microscopy. The results showed that the morphology state of the active layer exactly after spin coating process was very important parameter, which could dictate different responses of solar cells to a certain treatment. Using solvent additives to prolong the film formation period and storing in small dish could reach the morphology of the active layer near its best state in which there was no need to apply common post-treatment processes. A thickness at about 20 nm was required for Ca layer to effectively act as exciton blocking layer while LiF with 1 nm thickness worked better.     

Enhanced cycle performance of SiO-C composite anode for lithium-ion batteries

A silicon monoxide (SiO)-carbon composite prepared by ball-milling and pyrolysis is evaluated as an anode material for lithium-ion batteries. Electrochemical tests demonstrated that the first charge and discharge capacities of the material are about 1050 and 800 mAh g⁻¹, respectively, with a first-cycle efficiency of 76%. The disproportionation reaction of pure SiO into Si and SiO₂ during pyrolysis is confirmed by means of XRD and ²⁹Si MAS NMR. The cycle performance of this material shows an excellent reversible capacity retention of 710 mAh g⁻¹ over 100 cycles without any potential or capacity restrictions. This improved cycle performance is attributed to the stable microstructure, enhanced electrical contact afforded by the pyrolyzed carbon, and the amorphous phase transformation of the active material during cycling.     

Conceptual design of a web-based LNG plant management system through adoption of the integrated environment for design and maintenance

The present paper aims to suggest a web-based LNG (Liquefied natural gas) plant management system that is applicable from the design stage through the operational lifetime of the plant. The usefulness of this program is maximized by combining a virtual plant and RAMS (Reliability, availability, maintainability and safety). To achieve this goal, principles related to a virtual plant and RAMS are reviewed and several modules were designed. In particular, the RBI (Risk based inspection) module based on the API (American Petroleum Institute) code was developed for implementing RAMS. To review the design and deliver geometrical information regarding the system and processes, several commercial softwares are chosen to develop the navigator module and virtual module of LPMS-RAMS (LNG Plant Management System based on RAMS). Also, several modules related to maintenance and safety, are developed. It means that the LPMS-RAMS has many applicable modules based on the concept of virtual plant and RAMS. Especially, The VR (Virtual reality) module in this system will be useful during the design stage for diverse types of LNG plants. Also, the RAMS module is expected to improve the efficiency and safety of the LNG plant during its operation.