A practical approach to formulate stage–discharge relationship in natural rivers

This study proposes a new formulation technique for modeling stage–discharge relationship, as an alternative approach to standard regression techniques. An explicit neural network formulation (ENNF) is derived by using data obtained from United States Geological Survey data base. The neural network model is trained and tested using time series of daily stage and discharge data from two stations in Pennsylvania, USA. The model is compared with the standard rating curve (SRC) technique. Statistical parameters such as average, standard deviation, minimum, and maximum values, as well as criteria such as root mean square error, the efficiency coefficient (E), and determination coefficient (R ²) are used to measure the performance of the ENNF. Considerably, well performance is achieved in modeling streamflow by using ENNF. The comparison results reveal that the suggested formulations perform better than the conventional SRC.     

Estimation of Geomorphological Parameters of Lower Zab River-Basin by Using GIS-Based Remotely Sensed Image

The Lower Zab watershed is one of the most important catchment areas in the northern region of Iraq, as it includes large dam which is called Dukan Dam. Besides this, there are four other catchment areas, which are the Greater Zab (Upper Zab), Diyala, Khabur, and Uzem. During the last few decades like the other places in the world, the northern region of Iraq has been severely affected by the climatic changes, long-term drought, water shortage and some casual flood events. The former has impacted negatively on the wide range of areas in the region and continues to be a problem. However, the latter occasionally occurs during the winter season as a result of heavy rainfall and the lack of the required dams and artificial drainage. Both problems cause socio-economic damage in the region. This paper seeks to enhance water-based information in the region under study using the technique of GIS-based remotely sensed image that give us more accurate results and less time consuming to process data comparing with the GIS-based Topographic Maps (GTMs). This modern technique provides powerful and cost-effective tools for managing and processing data and creating maps for water resources. This would enable hydrologists and researchers to get better access to high quality hydrologic data. Thus, an accurate gemorphological parameters for watersheds and catchments can be calculated. Accordingly, more accurate hydraulic structures can be designed for the region under study.     

A myosignal-based powered exoskeleton system

This paper studies the integration of a human arm with a powered exoskeleton (orthotic device) and its experimental implementation in an elbow joint, naturally controlled by the human. The human-machine interface was set at the neuromuscular level, by using the neuromuscular signal (EMG) as the primary command signal for the exoskeleton system. The EMG signal along with the joint kinematics were fed into a myoprocessor which in turn predicted the muscle moments on the elbow joint. The moment-based control system integrated myoprocessor moment prediction with feedback moments measured at the human arm/exoskeleton and external load/exoskeleton interfaces. The exoskeleton structure under study was a two-link, two-joint mechanism, corresponding to the arm limbs and joints, which was mechanically linked by the human operator. Four indices of performance were used to define the quality of the human/machine integration and to evaluate the operational envelope of the system. Experimental results indicate the feasibility of an EMG-based power exoskeleton system as an integrated human-machine system using high-level neurological signals     

Fast Computation of the Acoustic Field for Ultrasound Elements

A fast method for computing the acoustic field of ultrasound transducers is presented with application to rectangular elements that are cylindrically focused. No closed-form solutions exist for this case but several numerical techniques have been described in the ultrasound imaging literature. Our motivation is the rapid calculation of imaging kernels for physics-based diagnostic imaging for which current methods are too computationally intensive. Here, the surface integral defining the acoustic field from a baffled piston is converted to a 3-D spatial convolution of the element surface and the Green's function. A 3-D version of the overlap-save method from digital signal processing is employed to obtain a fast computational algorithm based on spatial Fourier transforms. Further efficiency is gained by using a separable approximation to the Green's function through singular value decomposition and increasing the effective sampling rate by polyphase filtering. The tradeoff between accuracy and spatial sampling rate is explored to determine appropriate parameters for a specific transducer. Comparisons with standard tools such as Field II are presented, where nearly 2 orders of magnitude improvement in computation speed is observed for similar accuracy.     

A proposed application of an industrial DOS computer fordistribution substation monitoring and control

This paper presents the design and implementation of an intelligent controller intended for use in distribution substations to perform monitoring and control duties within the framework of distribution automation needs. The hardware of the developed controller is a DOS based industrial computer running on ECB-BUS. The application software handles all input/output tasks, data collection, manipulation and control design decisions with its flexible structure. This embedded controller measures bus voltage, transformer and feeder currents and calculates the real and reactive power, power factor, frequency, and total harmonic distortion of voltage and current. In addition to its local remote data acquisition and monitoring functions by means of console and SCADA outputs, the system, through its relay outputs, is capable of performing automation tasks such as integrated Volt/VAr control, overload and underfrequency detection and load shedding at the substation level. This reliable, high capacity and low cost system is completely programmable so that it can handle new requirements with new configurations easily     

Kinetics of the solid-state carbothermic reduction of wessel manganese ores

Reduction of manganese ores from the Wessel mine of South Africa has been investigated in the temperature range 1100 °C to 1350 °C with pure graphite as the reductant under argon atmosphere. The rate and degree of reduction were found to increase with increasing temperature and decreasing particle sizes of both the ore and the graphite. The reduction was found to occur in two stages: (1) The first stage includes the rapid reduction of higher oxides of manganese and iron to MnO and FeO. The rate control appears to be mixed, both inward diffusion of CO and outward diffusion of CO₂ across the porous product layer, and the reaction of carbon monoxide on the pore walls of the oxide phase play important roles. The values of effective CO-CO₂ diffusivities generated by the mathematical model are in the range from 2.15 x 10⁻⁵ to 6.17 X 10⁻⁵ cm².s⁻¹ for different ores at 1300 °C. Apparent activation energies range from 81. 3 to 94.6 kJ/kg/mol. (2) The second stage is slower during which MnO and FeO are reduced to mixed carbide of iron and manganese. The chemical reaction between the manganous oxide and carbon dissolved in the metal phase or metal carbide seems to be the rate-controlling process The rate constant of chemical reaction between MnO and carbide on the surface of the impervious core was found to lie in the range from 1.53 x 10⁻⁸ to 1.32 x 10⁻⁷ mol . s⁻¹ . cm⁻². Apparent activation energies calculated are in the range from 102.1 to 141.7 kJ/kg/mol. Formerly Doctoral Student, Department of Metallurgy and Materials Engineering, University of the Witwatersrand, Johannesburg,     

Adsorption of botulinum toxin to activated charcoal with a mouse bioassay

STUDY OBJECTIVE: We evaluated the effectiveness of activated charcoal (AC) in adsorbing Clostridium botulinum type A toxin using a mouse bioassay. DESIGN: Prospective, blinded, randomized, controlled animal study. SETTING: Animal care facility. PARTICIPANTS: One hundred forty Swiss/Webster ND-4 strain mice. INTERVENTION: Food contaminated with type A botulinum toxin was homogenized in a phosphate/gel buffer (pH 6.2). The concentrate was diluted by factors of 1:10, 1:50, and 1:100. AC was added to aliquots of the dilutions to a 20% final concentration. The samples were centrifuged, supernatant was removed, and separate groups of mice were injected intraperitoneally with .5 mL of each dilution (those treated with AC and controls untreated with AC). The animals were then observed over 5 days for signs of botulism. RESULTS: None of the 60 animals injected intraperitoneally with dilutions treated with AC was observed to have any signs of botulism. In contrast, deaths were observed in 10 of 20, 9 of 20 and 4 of 20 mice injected with untreated dilutions of 1:100, 1:50, and 1:10, respectively (P < .004). CONCLUSION: In this model, treatment of botulinum toxin with AC before administration resulted in greatly reduced morbidity and mortality.     

Synthesis, characterization and adsorption study of the uranyl ions by hydrogels based on polyethylene glycol and methacrylic acid copolymers

The water swelling polymeric hydrogels were obtained by γ-initiated radiation copolymerization of polyethylene glycol (PEG) with methacrylic acid (MAA) and three-ethylene glycol dimethacrylate (TEGDMA) as cross-linking agent. The main regularities of PEG-MAA network formation, deformation properties, structure and thermal characteristics depending on copolymer composition, molecular weight of PEG have been studied. The sorption of uranyl ions by PEG-MAA hydrogels in comparison with homopolymer PMAA was investigated. The effect of uranyl ions concentration on sorption efficiency of hydrogels was shown. The ability to regeneration in desorption process was demonstrated for PEG-MAA hydrogels in comparison with PMAA gel.     

Optoelectronic properties of thiazole‐based polythiophenes

In this work, two thiazole‐containing monomers N‐(thiazol‐2‐yl)?2‐(thiophen‐3‐yl)acetamide (ThDBTH) and N,N′‐([4,4′‐bithiazole]‐2,2′‐diyl)bis(2‐(thiophen‐3‐yl)acetamide) (Th₂DBTH) were synthesized through amidification reaction of 2‐(thiophen‐3‐yl)acetyl chloride with aminothiazole derivatives and characterized by FTIR and ¹H and ¹³C‐NMR. The monomers were subjected to electrochemical polymerization and optoelectronic properties of the resultant conducting polymers were investigated. Additionally, copolymerization of ThDBTH in the presence of thiophene was achieved. PThDBTH, PTh₂DBTH, and P(ThDBTH‐Th) exhibited optical band gaps of 2.15, 2.30, and 1.95 eV, respectively. Switching time and optical contrast of the polymers were evaluated via kinetic studies. The P(ThDBTH‐Th) revealed satisfactory switching time and appropriate optical contrast of 1.27 s and 24.97%, respectively. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42206.