Experimental investigation of CO<Subscript>2</Subscript> capture using sodium hydroxide particles in a fluidized bed

CO₂ capture from air using sodium hydroxide solid sorbent in a laboratory scale fluidized bed reactor was investigated experimentally. The influence of three parameters of temperature, inlet CO₂ volume percentage and inlet air flow rate on the CO₂ removal rate was studied. Experimental results showed that the optimum rate was at 25 °C when the inlet CO₂ volume percentage was 1%. The results also showed that the adsorption process was reactive, and the reaction mechanism depended on the reaction temperature. In addition, empirical observation revealed only one adsorption cycle happened at low temperatures (25-30 °C). As the temperature increased, the second adsorption cycle occurred and, finally, CO₂ desorption cycle took place in the range of 90-115 °C.     

Flutter and bifurcation instability analysis of fluid-conveying micro-pipes sandwiched by magnetostrictive smart layers under thermal and magnetic field

International Journal of Mechanics and Materials in Design - Fluid-conveying micro/Nano structures are key tools in MEMS and NEMS applications especially for drug delivery systems to attack a...     

Evaluating the sources and fate of anthropogenic dissolved inorganic nitrogen (DIN) in two contrasting North Sea estuaries

Nitrogen isotope ratios (delta(15)N) were used to help elucidate the sources and fate of ammonium (NH(4)(+)) and nitrate (NO(3)(-)) in two northeastern English estuaries. The dominant feature of NH(4)(+) in the heavily urbanised Tyne estuary was a plume arising from a single point source; a large sewage works. Although NH(4)(+) concentrations (ranging from 30-150 microM) near the sewage outfall varied considerably between surveys, the sewage-derived delta(15)N-NH(4)(+) signature was remarkably constant (+10.6+/-0.5 per thousand) and could be tracked across the estuary. As indirectly supported by (15)N-depleted delta(15)N-NO(3)(-) values observed close to the mouth of the Tyne, this sewage-derived NH(4)(+) was thought to initiate lower estuarine and coastal zone nitrification. In the more rural Tweed, NH(4)(+) concentrations were low (<7 microM) compared to those in the Tyne and delta(15)N-NH(4)(+) values were consistent with mixing between riverine and marine sources. The dominant form of dissolved inorganic nitrogen (DIN) in the Tweed was agricultural soil-derived NO(3)(-). A decrease in riverine NO(3)(-) flux during the summer coinciding with an increase in delta(15)N-NO(3)(-) values was mainly attributed to enhanced watershed nutrient processing. In the Tyne, where agricultural inputs are less important compared to the Tweed, light delta(15)N-NO(3)(-) (ca. 0 per thousand) detected in the estuary during one winter survey pointed to a larger contribution from precipitation-derived NO(3)(-) during high river discharge. Regardless of the dominant sources, in both estuaries most of the variability in DIN concentrations and delta(15)N values was explained by simple end-member mixing models, implying very little estuarine processing.     

A probabilistic framework for copy-move forgery detection based on Markov Random Field

Multimedia Tools and Applications - Copy-move forgery is one of the most common kind of image tampering where some part of an image is copied, may be with minor modifications, pasted to another...     

Modeling the Presence of Humic Acid in Ultrafiltration of Xenobiotic Compounds: Elman Recurrent Neural Network

Predicting the rejection of pesticides in ultrafiltration (UF) processes in the presence of common components of dissolved natural organic matter would be taken into consideration as a principle for surface water treatment. This paper presents the application of the Elman Recurrent Neural Network (ERNN) model, which has been trained with previously‐obtained experimental data so as to predict the rejection of a class of xenobiotic compounds (nitrophenols (NPs)) dynamically, in the absence and in the presence of humic acid at neutral and acidic conditions. For each trained network, the training function, number of neurons in the hidden and output layers, number of epochs, train and test MSE (mean square error) and MRE (mean relative error) were compared to find the best ERNN. The trained MRE and test MSE for all NPs at the neutral condition was, respectively, less than 1.03 % (4.9 % at acidic condition) and 2.4 % (2.01 % at acidic condition), which showed high network reliability.     

Charge storage mechanism of sonochemically prepared MnO2 as supercapacitor electrode: Effects of physisorbed water and proton conduction

The charge storage mechanism of nanostructured hydrated manganese dioxide, as a supercapacitor electrode, was investigated with respect to the role of amount of hydrates on the electrolyte cations diffusion. The MnO₂ materials (γ- and layered types), prepared by a novel ultrasonic aided procedure. Thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize the water content of the samples. The samples then were heat-treated in air for 2 h at 70, 100 and 150 °C to prepare different γ- and L-series of electrodes with various amounts of hydrates. To determine the role of the protonic conduction on the charge storage mechanism, the electrochemical properties of the electrodes were investigated in two different electrolyte pH values of 3.3 and 6.Compared to γ25, the higher specific capacitance of L25, especially in more acidic electrolytes, is attributed to the higher amount of physically adsorbed water molecules and their contribution in diffusion process. Furthermore, it is clearly demonstrated that the total electrochemical performance of the systems under consideration is also influenced by the crystalline structure of the prepared electrodes, especially when the size of the tunnels limits the intercalation of cations.Analyzing the results of cyclic voltammetry and electrochemical impedance spectroscopy for both series of the electrodes, revealed that, increasing the heat-treatment temperature makes the charge-transfer resistance increase and the Warburg impedance decrease. This effect can be attributed to the more amount of surface physisorbed water lost by the higher heat-treatment temperatures.     

Ultra-high-precision alignment of the elastomerically mounted elements of the science camera lenses for the Mars Science Laboratory (MSL) rover

Cameras built for space exploration are required to meet stringent environmental conditions, such as thermal and dynamic loads for both the optics (camera lens) and imaging electronics. On a multitude of spaceborne imaging instruments, optical elements are supported in their mounts via an elastomeric bonding approach using a room temperature vulcanizing silicone as the bonding agent. Employing this integration method, we achieved element-to-element alignment, measured as the total indicated runout, using a high-precision contact probe to be on the order of half a wavelength of He-Ne laser light, or 0.3?μm, on the Malin Space Science Systems lenses for the Mars Science Laboratory (MSL) cameras. This is a higher precision than the current industry state-of-the-art, and it was achieved for the very challenging small diameter lens elements. This paper describes the design philosophy, implementation, and integration method that resulted in achieving this level of precision for interelement alignment. The results are based on actual measurements that were made during the process of building the MSL rover's science camera lenses, namely Mastcams, the Mars Hand Lens Imager, and the Mars Descent Imager. The optical designs of these cameras lenses are described in detail in [Opt. Eng.48, 103002 (2009)], while further information on the four science cameras can be found at http://www.msss.com.     

Centralized Key Management Scheme in Wireless Sensor Networks

Today, key management is widely recognized as an important aspect of security in wireless sensor networks. In these networks, sensor nodes can be either mobile or static. Therefore, supporting the mobility of the nodes can be regarded as a purpose of key management schemes. In our previous work, we presented a key management scheme that was more efficient with respect to security and connectivity compared to the other ones. In that scheme, it is assumed that the nodes are static. In this paper we are going to present a scheme that supports the mobility of the nodes and makes the initial scheme more flexible. The basic criterion for the evaluation of the scheme is the communication overhead. First, the nodes establish a secure link with the cluster heads and then establish a secure link among themselves with the help of the cluster heads. We have analyzed this scheme with regards to the communication overhead and we will compare it with the other schemes.     

Motion history image: its variants and applications

The motion history image (MHI) approach is a view-based temporal template method which is simple but robust in representing movements and is widely employed by various research groups for action recognition, motion analysis and other related applications. In this paper, we provide an overview of MHI-based human motion recognition techniques and applications. Since the inception of the MHI template for motion representation, various approaches have been adopted to improve this basic MHI technique. We present all important variants of the MHI method. This paper points some areas for further research based on the MHI method and its variants.     

Single-phase photo-cross-linkable adhesive synthesized from methacrylic acid-grafted 1-decene/9-decene-1-ol cooligomer

The cooligomerization of 1-decene with 9-decene-1-ol was conducted by using a Ti amine bis-phenolate catalyst. Light-curable adhesive was prepared by the reaction of methacryloyl chloride with the hydroxyl groups of the synthesized cooligomer, which led to the introduction of photo-polymerizable CC double bonds into the cooligomer chains. Comonomer insertion into 1-decene oligomeic chains and also methacryloyl chloride reaction with cooligomer were confirmed by both FT-IR and NMR spectroscopy. Three-point bending analysis results of cured adhesive sample (cured with blue light) showed flexural modulus and flexural strength values of 1.41 GPa and 1.66 MPa, respectively. Maximum weight loss temperature of 444°C showed high thermal stability of cured adhesive sample. In order to explore adhesion abilities of the synthesized adhesive to different substrates including polymethylmethacrylate (PMMA), polycarbonate (PC), polystyrene (PS), nylon and aluminum (Al), tensile shear bond strength, and peeling tests were conducted. Synthesized adhesive demonstrated tensile shear strength values of 1.28, 1.95, 1.10, 2.15, and 2.42 N/mm² for PMMA, PC, PS, nylon, and Al substrates, respectively. Furthermore, obtained adhesive indicated greater tendency to polar substrates in comparison to nonpolar ones by the factor of 16–95%. Obtained results suggested a new photo-curable adhesive with privileged features, which has capability to be used in high temperature applications.