Integrative approach to design techniques

This paper summarizes a comprehensive approach to and arranges systematically theories and techniques of planning and design (P and D). Environmental P and D is expressed in terms of P and D theories, applied techniques and tools. Theories are categorized from abstract to real world applications, according to their basic characteristics: professional or user based. Matrices are set up for three basic fields of study: the application of current theories in P and D, the basic disciplines and current theories, and the research tools and techniques for different stages of the P and D process. Finally a conceptual framework is established for P and D.     

Gilbert Damping Constant of Quaternary Co2MnAl1?x Sn x Heusler Alloy Thin Films

Polycrystalline quaternary Co₂MnAl_1?x Sn _x films with x=0.25, 0.5, 0.75,?1 were prepared at room temperature using magnetron sputtering technique on SiO₂ substrates and post-annealed at various temperatures. We investigated the crystal structures, magnetic properties, and magnetic damping constants (??) of the prepared films. Out-of-plane angular dependences of the resonance field and the linewidth of the ferromagnetic resonance spectra were measured and analyzed using the Landau?CLifshitz?CGilbert equation to determine the magnetic properties and damping constant. Co₂MnAl_0.75Sn_0.25 and Co₂MnSn films had A2 ordered crystal structure while Co₂MnAl_0.25Sn_0.75 and Co₂MnAl_0.5Sn_0.5 films had A2 ordering up to 400?°C and 300?°C annealing temperature, respectively, and they had B2 ordering for the remaining temperatures. Also the crystal structure deteriorated at 600?°C for all of the film systems. The saturation magnetization, M _S , of films increased with annealing temperature till 400?°C except Co₂MnAl_0.5Sn_0.5 in which M _S increased till 500?°C, which is consistent with the structural analysis. The effective magnetization was obtained from the FMR spectra and it was found that it decreased with increasing Sn-concentration and reached a minimum value at Co₂MnAl_0.25Sn_0.75 composition. Lastly, Co₂MnAl_1?x Sn _x films annealed at 500?°C showed the best crystal ordering. The lowest ?? value was 0.008 and obtained from Co₂MnAl_0.5Sn_0.5 films annealed at 500?°C.     

Optical investigation of thin films of liquid–crystalline lutetium bisphthalocyanine

Thin films of bis[4,5,4,5,4,5,4,5]-octakis(hexylthiophthalocyanine) of lutetium(III) were prepared by spin coating at different speeds in the range of 2000–6000 rpm. The films undergo phase transition on heat treatment at temperatures above 120 °C and the formation of a mesophase. The Q-bands in the visible absorption spectra of the films are broader and become red shifted compared to ones obtained for molecules in chloroform solution. Heat treatment produces molecular ordering, which is believed to be due to the edge-to-edge interaction between neighboring Pc moieties. Reduced film thickness and changes in optical constants are also attributed to thermally induced molecular reorganization corresponding to the liquid crystalline phase. AFM and polarized microscopy images are consistent with the phase transformations.     

Tetrakis(alkylthio)-substituted lutetium bisphthalocyanines for sensing NO2 and O3

In this study, the nitrogen dioxide (NO₂) and ozone (O₃) sensing properties of a series bis[tetrakis(alkylthio) phthalocyaninato] lutetium(III) complexes [(C_nH_2n+1S)₄Pc]₂Lu(III) (n = 6, 10, 16) are investigated as a function of concentration in the temperature range between 25 °C and 150 °C. The concentration ranges were 1–10 ppm for NO₂, and 50 ppb–1 ppm for O₃. The response time and the sensor response to NO₂ are measured for approximately 1 min and 100% ppm⁻¹, respectively, for compound 1 at room temperature. At room temperature, all compounds are in the solid phase. The response time decreases to a few seconds with increasing operation temperature to 150 °C. At this temperature, all compounds are in the liquid crystal phase. The fastest response to oxidizing gases is observed at the liquid crystal phase of the Pcs. It has also been observed that the response time and the sensor response depend on the alkyl chain lengths of the Pcs. The doping effect of oxygen has been determined under high purity nitrogen N₂ flow, after exposure to dry air, at a different period of time and after annealing. It has been found that the conductivities of [(C_nH_2n+1S)₄Pc]₂Lu(III) thin films increased after exposure to dry air and the conduction mechanism also changed from ohmic behavior to space-charge-limited conduction.     

Use of the electrochromic behaviour of lanthanide phthalocyanine films for nicotinamide adenine dinucleotide detection

Electrochromic properties of spun films of bis[octakis(hexylthio)phthalocyaninato] dysprosium(III) were investigated for determining nicotinamide adenine dinucleotide hydride (NADH) in water solutions. A spin-coated film deposited on indium tin oxide electrode displays only one redox couple (at E1/2=0.78V). The films of [(C6H13S)8Pc]2Dy were modified chemically or electrochemically for the detection of reduced NADH in water solution. The modified film in the oxidized ([(C6H13S)8Pc]2Dy)+ form is believed to be reduced to its neutral form on interaction with NADH.     

Investigation of gas-sensing properties of copper phthalocyanine films

In this work, the sensor response of thin films of octasubstituted copper phthalocyanine derivative (CuPcR₈) with bulky substituents on R = –N(SO₂C₆H₅–CH₃)CH₂(CH₂)₈CH₃ to the vapour of benzene, chloroform, ethanol and butanol were investigated by surface plasmon resonance technique. The application and some advantages of total internal reflection ellipsometry method for determination of the organic vapours are also demonstrated.     

Effect of Ti sublayer on the ORR catalytic efficiency of dc magnetron sputtered thin Pt films

A series of thin Pt films were deposited by dc magnetron sputtering directly on a commercial hydrophobic carbon paper substrate having a thin microporous Vulcan-XC72 layer or upon a thin Ti sublayer sputtered on the top of the microporous carbon film. The electrocatalytic properties of the sputtered Pt films toward the oxygen reduction reaction were investigated in 0.5 M H₂SO₄ solution and in a hydrogen PEM fuel cell. The catalyst with ultralow Pt loading of 22 μg cm⁻² deposited on a 33 Å thick Ti sublayer is robust, mechanically stable, possesses highly developed surface area and improved catalytic efficiency. Its performance as a MEA cathode in a single hydrogen PEM fuel cell (577 mA cm⁻² at 0.4 V cell voltages and a maximum power of 0.954 W) proved to be much superior compared to that of MEA with the same cathode Pt loading but without Ti sublayer (173 mA cm⁻² at 0.4 V, 0.231 W, respectively).     

Ultrasound as pretreatment for drying garlic slices in microwave and convective dryer

Food Science and Biotechnology - The effects of ultrasound pretreatment (US) before hot air drying (HAD) and microwave drying (MWD) of garlic slices were investigated. For this aim ultrasonic bath...