The spatial and temporal distribution of metals in an urban stream: A case study of the Don River in Toronto,Canada

Widespread growth of cities, the association of trace metals with urban runoff, and the potentially deleterious effect of metals on aquatic ecology have made it important to understand the distribution and transport of metals through surface water channel networks. The Don River in Toronto, Canada has been identified as an Area of Concern for pollution to Lake Ontario, with historically high levels of metal contamination. Sampling programs are sparse, therefore a model is needed to understand the spatial and temporal variability of metals in the river network. The objectives of the current study are to: i) describe the sampled spatial and temporal variability of metals in the Don River and ii) develop a modelling strategy to describe within flood metal transport dynamics. A model setup tool is developed that links Storm Water Management Model (SWMM) with the Environmental Fluid Dynamics Code (EFDC) to allow a seamless transition from catchment hydrology to in-stream hydraulic and chemical processes. Results show that lead pollution in the Don River is decreasing, likely as a result of policy changes and sediment dredging in the mouth of the river. However, zinc and copper pollution are increasingly problematic, with copper exceeding recommended lower guidelines, particularly during floods. Model results confirm that most of the sediment and metals are transported in relatively short bursts within longer flood durations and are stored in depositional hotspots within the Lower Don River. A better monitoring strategy is needed to understand and more accurately parametrize these processes in an urban river system.     

ReliaCloud‐NS: A scalable web‐based simulation platform for evaluating the reliability of cloud computing systems

This paper discusses the implementation, architecture, and use of a graphical web‐based application called ReliaCloud‐NS that allows users to (1) evaluate the reliability of a cloud computing system (CCS) and (2) design a CCS to a specified reliability level for both public and private clouds. The software was designed with a RESTful application programming interface for performing nonsequential Monte Carlo simulations to perform reliability evaluations of a CCS. Simulation results are stored and presented to the user in the form of interactive charts and graphs from within a web browser. The software contains multiple types of CCS components, simulations, and virtual machine allocation schemes. ReliaCloud‐NS also contains a novel feature that evaluates CCS reliability across a range of varying virtual machine allocations and establishes and graphs a CCS reliability curve. This paper discusses the software architecture, the interactive web‐based interface, and the different types of simulations available in ReliaCloud‐NS and presents an overview of the results generated from a simulation.     

Influence of gamma irradiation on structural,optical, and electrical characterization of Bi2S3 thin films

The induced effects of the gamma rays on properties of bismuth sulfide (Bi₂S₃) thin films synthesized using successive ionic layer adsorption and reaction (SILAR) have been investigated in details in this work. The Bi₂S₃ thin films are prepared on glass substrate and then exposed with low gamma radiation dose in the range of 0–1000 Gy. X-ray diffraction (XRD) confirmed the orthorhombic structural phase. Also, it was noticed in the XRD result that the crystallite size decreased from 115.29 to 73.63 nm with increasing gamma rays doses. For surface properties as well as stoichiometry of the prepared and irradiated thin film have been studied by field emission scanning electron microscope (FESEM). The optical transmission of irradiated samples increased and the energy band gap (E) decreased from 2.78 to 2.52 eV with gamma dose. Photoluminescence (PL) spectra revealed the improvement in the emission characteristics of Bi₂S₃ thin films with irradiation in the range of 250–1000 Gy. Impedance spectroscopy investigation exhibited that the resistance due to grain boundaries meaningfully contributed to the electrical characteristics of the Bi₂S₃ thin films. The achieved results suggested that Bi₂S₃ thin films are a good tool for further study of dosimetry and radiation sensing application.

     

Understanding the Time and Frequency Varying Characteristics of a Multipath Wireless Channel

Designing a spectrally efficient wireless channel requires a comprehensive understanding of its time and frequency varying characteristics, making it a stochastic medium of communication. These characteristics become more challenging to cater at the receiving terminal in a multipath transmission. This is because of the fading effect and Doppler shift of the transmitted frequency, specifically in cellular mobile radio systems and vehicle to vehicle communications. This paper presents the modeling, simulation, and then characterization of a cellular mobile radio multipath channel over its time and frequency varying fading gain. For this purpose, a discrete-time Finite Impulse Response (FIR) type filter of such a channel is designed, modeled, and simulated using time and frequency varying characteristics of the received signal. The simulated channel response is further analyzed in terms of coherence bandwidth, coherence time, delay spread, Doppler spread, and symbol time.

     

Modified poly(vinyl alcohol)/chitosan blended membranes for isopropanol dehydration via pervaporation: Synthesis optimization and modeling by response surface methodology

Box–Behnken (BB) design of response surface methodology (RSM) was effectively applied to optimize fabrication conditions of modified poly(vinyl alcohol) (PVA) and chitosan (CS) blended pervaporation (PV) membranes. The PVA/CS membranes were crosslinked either by chemical reaction with glutaraldehyde (GA) or by heat‐treating at different temperatures. The main objectives were to determine the optimal levels of fabricating parameters and also to investigate interactions among the variables. CS content in the blended membranes, concentration of crosslinking agent and heat‐treating temperature were the fabrication parameters, the main effects and interaction effects of which on membrane structure and PV performance toward isopropanol (IPA)/water dehydration were investigated, and for which regression models were established. The modified PVA/CS blended membranes were characterized by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) as well as X‐ray diffraction (XRD). It was found that the CS content is the most significant factor influencing flux and separation factor among the three studied variables and the experimental results are in excellent accordance with predicted values from the developed RSM regression models. The RSM results indicated that under preparation conditions of 80 wt % CS in the blended membrane, 0.58 wt % GA concentration, and 77 °C heat‐treating temperature, the maximum separation factor of 5222.8 and the normalized flux of 9.407 kg µm/m²h can be acquired with feed content of 85 wt % IPA at 25 °C, showing that the prepared membrane is highly efficient for PV dehydration of IPA. The models were satisfactorily validated against experimental data. Furthermore, the optimum membrane presents excellent separation performance at different feed compositions and temperatures. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44587.     

Adsorption of platinum(IV) from an aqueous solution with magnetic cellulose functionalized with thiol and amine as a nano‐active adsorbent

In this study, magnetic cellulose was prepared and then functionalized by the grafting of glycidyl methacrylate and reaction with thiourea/amine [to produce grafted magnetic cellulose with thiol/amine (GMC–N/S)]. Thus, GMC–N/S as a nano‐active adsorbent was investigated for the adsorption of Pt(IV) in a batch system. A response surface methodology was used to study the effects of four independent variables [Pt(IV) concentration, temperature, pH of the solution, and adsorbent dose] and to optimize the process conditions for the maximum adsorption of platinum(IV) from aqueous solutions by GMC–N/S. A high coefficient of determination (R² = 98.46) implied the adsorption of Pt(IV) onto the adsorbent in a valid manner, and only 1.54% of the total variable was not explained by the model. The equilibrium adsorption data were fitted to the Langmuir isotherm. The maximum monolayer adsorption capacity of the adsorbent (GMC–N/S) for Pt(IV) was determined to be 40.48 mg/g. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45361.     

Effect of Slag Composition on the Crystallization Kinetics of Synthetic CaO-SiO<Subscript>2</Subscript>-Al<Subscript>2</Subscript>O<Subscript>3</Subscript>-MgO Slags

The crystallization kinetics of CaO-SiO₂-Al₂O₃-MgO (CSAM) slags was studied with the aid of single hot thermocouple technique (SHTT). Kinetic parameters such as the Avrami exponent (n), rate coefficient (K), and effective activation energy of crystallization (E _A ) were obtained by kinetic analysis of data obtained from in situ observation of glassy to crystalline transformation and image analysis. Also, the dependence of nucleation and growth rates of crystalline phases were quantified as a function of time, temperature, and slag basicity. Together with the observations of crystallization front, they facilitated establishing the dominant mechanisms of crystallization. In an attempt to predict crystallization rate under non-isothermal conditions, a mathematical model was developed that employs the rate data of isothermal transformation. The model was validated by reproducing an experimental continuous cooling transformation diagram purely from isothermal data.     

Real time monitoring of bioreactor mAb IgG3 cell culture process dynamics via Fourier transform infrared spectroscopy: Implications for enabling cell culture process analytical technologyŽ 

Compared to small molecule process analytical technology (PAT) applications, biotechnology product PAT applications have certain unique challenges and opportunities. Understanding process dynamics of bioreactor cell culture process is essential to establish an appropriate process control strategy for biotechnology product PAT applications. Inline spectroscopic techniques for real time monitoring of bioreactor cell culture process have the distinct potential to develop PAT approaches in manufacturing biotechnology drug products. However, the use of inline Fourier transform infrared (FTIR) spectroscopic techniques for bioreactor cell culture process monitoring has not been reported. In this work, real time inline FTIR Spectroscopy was applied to a lab scale bioreactor mAb IgG3 cell culture fluid biomolecular dynamic model. The technical feasibility of using FTIR Spectroscopy for real time tracking and monitoring four key cell culture metabolites (including glucose, glutamine, lactate, and ammonia) and protein yield at increasing levels of complexity (simple binary system, fully formulated media, actual bioreactor cell culture process) was evaluated via a stepwise approach. The FTIR fingerprints of the key metabolites were identified. The multivariate partial least squares (PLS) calibration models were established to correlate the process FTIR spectra with the concentrations of key metabolites and protein yield of in-process samples, either individually for each metabolite and protein or globally for all four metabolites simultaneously. Applying the 2^nd derivative pre-processing algorithm to the FTIR spectra helps to reduce the number of PLS latent variables needed significantly and thus simplify the interpretation of the PLS models. The validated PLS models show promise in predicting the concentration profiles of glucose, glutamine, lactate, and ammonia and protein yield over the course of the bioreactor cell culture process. Therefore, this work demonstrated the technical feasibility of real time monitoring of the bioreactor cell culture process via FTIR spectroscopy. Its implications for enabling cell culture PAT were discussed.     

Energy intensity and greenhouse gases footprint of metallurgical processes: A continuous steelmaking case study

The demand on primary energy resources of three steelmaking technologies has been evaluated using an integrated energy analysis approach that takes into account the energy equivalent of major materials and supplies used in the process, as well as the inefficiency of electricity generation. Two new parameters, Material CO₂ Footprint (MCF) and Process CO₂ Footprint (PCF), are defined to provide unified measures for carbon footprint of the treated materials, and the process respectively. Using these measures, a comparative study of the three processes has been performed. It is demonstrated that a novel steelmaking technology that operates continuously leads to substantial reduction in the overall energy demand, when compared with the conventional batch processes. CO₂ reduction associated with the improvement of the energy efficiency is presented for several scenarios of power generation.