Ultradispersed particles in heavy oil: Part II, sorption of H2S(g)

During steam assisted gravity drainage for heavy oil recovery aqua-thermolysis reactions take place, whereupon gaseous hydrogen sulfide, H₂S_(g), is produced. A method to capture H₂S_(g) and convert it into a chemically inactive species is deemed necessary for sustaining in-situ recovery and upgrading. Part I of the current study explored the formation and stabilization of colloidal FeOOH particles in heavy oil matrices. In this Part, we evaluate the H₂S_(g) sorption ability of these particles as well as other metal oxide/hydroxide particles. Furthermore, the effect of mixing and temperature on H₂S_(g) sorption was investigated. Results showed that the rate and capacity of H₂S_(g) sorption increased as the concentration of FeOOH increased. Mixing, on the other hand, had insignificant effect on the sorption capacity, however it improved the sorption kinetics. In addition, in-situ prepared colloidal particles showed better reactivity towards H₂S_(g) than commercial α-Fe₂O₃ nanoparticles. Temperature had an adverse effect on the H₂S_(g) sorption capacity of FeOOH. This was attributed to a change in chemical structure of FeOOH as the temperature increased. Nevertheless, in-situ prepared ZnO colloidal particles completely removed H₂S_(g) even at high temperatures.     

Speech emotion recognition using optimized genetic algorithm-extreme learning machine

Multimedia Tools and Applications - Automatic Emotion Speech Recognition (ESR) is considered as an active research field in the Human-Computer Interface (HCI). Typically, the ESR system is...     

Effect of Magnetostatic Dipoles Interaction on the Initial Susceptibility of a Dilute Ferrofluid in One Dimension

The magnetization and the initial susceptibility have been calculated for a one-dimensional linear chain structured dilute ferrofluid considering nearest neighbor magnetic interaction for N-particles. The initial susceptibility is calculated as a function of the orientation angle between the field and the chain direction. Our results predict Curie–Weiss behavior for a one-dimensional magnetic fluid, and showed that the ordering temperature T ₀ depends on the particles separation in a very complicated way. This more general case of calculation reduces to simple results found by the Dimer and Trimer models when N equals 2 and 3, respectively.     

Thermal Modeling of Hybrid Storage Clusters

There is a lack of thermal models for storage clusters; most existing thermal models do not take into account the utilization of hard drives (HDDs) and solid state disks (SSDs). To address this problem, we build a thermal model for hybrid storage clusters that are comprised of HDDs and SSDs. We start this study by generating the thermal profiles of hard drives and solid state disks. The profiling results show that both HDDs and SSDs have profound impacts on temperatures of storage nodes in a cluster. Next, we build two types of hybrid storage clusters, namely, inter-node and intra-node hybrid storage clusters. We develop a model to estimate the cooling cost of a storage cluster equipped with hybrid storage nodes. The thermal model is validated against data acquired by temperature sensors. Experimental results show that, compared to the HDD-first strategy, the SSD-first strategy is an efficient approach to minimize negative thermal impacts of hybrid storage clusters.     

Toward improved control of prosthetic fingers using surface electromyogram (EMG) signals

A fundamental component of many modern prostheses is the myoelectric control system, which uses the electromyogram (EMG) signals from an individual’s muscles to control the prosthesis movements. Despite the extensive research focus on the myoelectric control of arm and gross hand movements, more dexterous individual and combined fingers control has not received the same attention. The main contribution of this paper is an investigation into accurately discriminating between individual and combined fingers movements using surface EMG signals, so that different finger postures of a prosthetic hand can be controlled in response. For this purpose, two EMG electrodes located on the human forearm are utilized to collect the EMG data from eight participants. Various feature sets are extracted and projected in a manner that ensures maximum separation between the finger movements and then fed to two different classifiers. The second contribution is the use of a Bayesian data fusion postprocessing approach to maximize the probability of correct classification of the EMG data belonging to different movements. Practical results and statistical significance tests prove the feasibility of the proposed approach with an average classification accuracy of ≈90% across different subjects proving the significance of the proposed fusion scheme in finger movement classification.     

Nucleophilic substitution sulfonation in emulsions: Formation of sodium benzyl sulfonate

Benzyl bromide was sulfonated at 298 K in emulsions formed with dioctyldimethylammonium bromide, or chloride. If mixing was sufficient, the emulsion was maintained throughout the reaction period. Lower conversions were obtained whenever benzyl bromide phase separated from the mixture. Chloride as surfactant counterion gave higher reaction rate, but decreased the conversion to C₇H₇SO₃^?Na⁺due to formation of benzyl chloride. The conversion to C₇H₇SO₃^?Na⁺ displayed a broad maximum as R₂(Me)₂^?N⁺Br concentration increased. Except at low concentration, the reaction rate increased with the concentration of Na₂SO₃ in accord with the S_N2 mechanism. The reaction rate increased with the reactant concentrations until interface saturation was achieved, suggesting that product formation did not interfere with the access of the reactants to the interface.     

Electromechanical Response of Piezoelectric Honeycomb Foam Structures

A finite element model is developed to characterize the complete electromechanical properties of the most general form of elastically anisotropic and piezoelectrically active foams with honeycomb structures. Four classes of piezoelectric honeycomb structures are identified depending on the relative orientation of the poling direction with the porosity direction (longitudinal and transverse) and the geometry of the honeycombs (isotropic and anisotropic). It is observed that: (i) Most of the elastic, dielectric, and piezoelectric constants of the longitudinally porous honeycomb foams exhibit linear dependence on the volume fraction (or relative density) of the material; (ii) The electromechanical properties of transversely porous foam structures (with the exception of C₂₂ and κ₂₂) exhibit significant dependence on the shape of the porosity; (iii) The piezoelectric figures of merit of the longitudinally porous foams do not exhibit significant dependence on the shape of the porosity; (iv) The piezoelectric figures of merit of the transversely porous foams exhibit a strong dependence on the shape of the porosity with the hexagonal foams exhibiting enhanced hydrostatic strain coefficient and lower acoustic impedance while the square foams exhibiting enhanced piezoelectric coupling constant and hydrostatic figure of merit; (v) In transversely porous anisotropic honeycomb structures, the shear elastic constants such as C₁₂ and C₆₆ and some figures of merit are enhanced significantly when compared to their isotropic counterparts. For example, in the PZT–7A transversely porous anisotropic honeycomb structures with 10% relative density, the hydrostatic figure of merit is expected to be 2485% greater than that predicted for the transversely porous isotropic honeycomb structures.     

Shape Memory Polyurethane as a Drilling Fluid Lost Circulation Material

Drilling fluid loss is a major problem with serious economic and environmental consequences. The use of traditional lost circulation materials (LCMs) to seal wide fractures increases the risk of bit nozzle plugging. In this work, smart LCMs based on shape memory polyurethane (SMPU) are proposed for the first time. SMPU can be programmed to recover at temperatures suited to a given well. As such, SMPU smoothly passes through the bit nozzles, while effectively seal wide fractures once activated. The SMPU is prepared by two step pre-polymerization and characterized by Fourier transform infrared spectra, X-ray diffraction, and differential scanning calorimeter. The SMPU is programmed by changing and fixing the original shape to a temporary shape through a thermo-mechanical process. The shape memory behavior of SMPU is analyzed by tensile apparatus. Compatibility of SMPU with WBMs is determined from mud rheology and filtration tests. Fracture sealing efficiency and shape recovery of SMPU are evaluated by a modified particle permeability apparatus fitted with a model fracture. The results confirm high sealing and shape recovery attributes of SMPU. The plug formed at 114 kg m^–3 SMPU and 80 °C experiences a sealing pressure of 100 bar with 71.5 cm³ cumulative fluid loss.     

Automatically identifying changes that impact code-to-design traceability during evolution

An approach is presented that automatically determines if a given source code change impacts the design (i.e., UML class diagram) of the system. This allows code-to-design traceability to be consistently maintained as the source code evolves. The approach uses lightweight analysis and syntactic differencing of the source code changes to determine if the change alters the class diagram in the context of abstract design. The intent is to support both the simultaneous updating of design documents with code changes and bringing old design documents up to date with current code given the change history. An efficient tool was developed to support the approach and is applied to an open source system. The results are evaluated and compared against manual inspection by human experts. The tool performs better than (error prone) manual inspection. The developed approach and tool were used to empirically investigate and understand how changes to source code (i.e., commits) break code-to-design traceability during evolution and the benefits from such understanding. Commits are categorized as design impact or no impact. The commits of four open source projects over 3-year time durations are extracted and analyzed. The results of the study show that most of the code changes do not impact the design and these commits have a smaller number of changed files and changed less lines compared to commits with design impact. The results also show that most bug fixes do not impact design.