Analysis of the eutrophication in a wetland using a data-driven model.

Eutrophication is a major problem in the international Anzali wetland (northern Iran). The present research initially aimed to determine the trophic state index (TSI) in ten sampling sites in the main parts of the Anzali wetland (western, eastern, central, and Siahkeshim parts). After determining the TSI in the wetland, a data-driven method (classification tree model with a J48 algorithm) was implemented to predict the trophic condition in the wetland based on a set of water quality and physical-structural variables. One hundred twenty samples related to chlorophyll-a (the model's output) and environmental variables (the model's inputs) were measured monthly during 1-year study period (2017-2018). Based on the TSI calculation, the western, Siahkeshim, eastern, and central parts of the wetland are classified as eutrophic, super-eutrophic, hyper-eutrophic, and hyper-eutrophic, respectively. When all environmental variables were introduced to the model (with five-time randomization effort, pruning confidence factor = 0.01, and seven-fold cross-validation), eight variables (bicarbonate, pH, water temperature, electric conductivity, dissolved oxygen, total phosphorus, water depth, and water turbidity) were predicted by the model. The model predicted that an increase in total phosphate, water turbidity, and electric conductivity concentration may contribute to the hyper-eutrophic state of the wetland. In contrast, the hyper-eutrophic of the wetland is associated with a decrease in water depth, dissolved oxygen, and pH concentration. According to ANOVA test, the trophic condition in the wetland can be affected by spatial and temporal patterns. Anthropogenic pressures such as the influx of chemicals particularly the nutrients (phosphorus and nitrogen) are the main cause of water enrichment (eutrophication problem) in main parts of the Anzali wetland ecosystem.

Utility of Biogenic Iron and Its Bimetallic Nanocomposites for Biomedical Applications: A Review.

Nanotechnology mainly deals with the production and application of compounds with dimensions in nanoscale. Given their dimensions, these materials have considerable surface/volume ratios, and hence, specific characteristics. Nowadays, environmentally friendly procedures are being proposed for fabrication of Fe nanoparticles because a large amount of poisonous chemicals and unfavorable conditions are needed to prepare them. This work includes an inclusive overview on the economical and green procedures for the preparation of such nanoparticles (flower, fruits, tea, carbohydrates, and leaves). Pure and bimetallic iron nanoparticles, for instance, offer a high bandwidth and excitation binding energy and are applicable in different areas ranging from antibacterial, anticancer, and bioimaging agents to drug delivery systems. Preparation of nano-sized particles, such as those of Fe, requires the application of high quantities of toxic materials and harsh conditions, and naturally, there is a tendency to develop more facile and even green pathways (Sultana, Journal of Materials Science & Technology, 2013, 29, 795-800; Bushra et al., Journal of hazardous materials, 2014, 264, 481-489; Khan et al., Ind. Eng. Chem. Res., 2015, 54, 76-82). This article tends to provide an overview on the reports describing green and biological methods for the synthesis of Fe nanoparticles. The present review mainly highlights selenium nanoparticles in the biomedical domain. Specifically, this review will present detailed information on drug delivery, bioimaging, antibacterial, and anticancer activity. It will also focus on procedures for their green synthesis methods and properties that make them potential candidates for various biomedical applications. Finally, we provide a detailed future outlook.

High-temperature high-pressure microfluidic system for rapid screening of supercritical CO2 foaming agents.

CO2 foam helps to increase the viscosity of CO2 flood fluid and thus improve the process efficiency of the anthropogenic greenhouse gas's subsurface utilization and sequestration. Successful CO2 foam formation mandates the development of high-performance chemicals at close to reservoir conditions, which in turn requires extensive laboratory tests and evaluations. This work demonstrates the utilization of a microfluidic reservoir analogue for rapid evaluation and screening of commercial surfactants (i.e., Cocamidopropyl Hydroxysultaine, Lauramidopropyl Betaine, Tallow Amine Ethoxylate, N,N,N' Trimethyl-N'-Tallow-1,3-diaminopropane, and Sodium Alpha Olefin Sulfonate) based on their performance to produce supercritical CO2 foam at high salinity, temperature, and pressure conditions. The microfluidic analogue was designed to represent the pore sizes of the geologic reservoir rock and to operate at 100 °C and 13.8 MPa. Values of the pressure drop across the microfluidic analogue during flow of the CO2 foam through its pore network was used to evaluate the strength of the generated foam and utilized only milliliters of liquid. The transparent microfluidic pore network allows in-situ quantitative visualization of CO2 foam to calculate its half-life under static conditions while observing if there is any damage to the pore network due to precipitation and blockage. The microfluidic mobility reduction results agree with those of foam loop rheometer measurements, however, the microfluidic approach provided more accurate foam stability data to differentiate the foaming agent as compared with conventional balk testing. The results obtained here supports the utility of microfluidic systems for rapid screening of chemicals for carbon sequestration or enhanced oil recovery operations.

Application of quadratic linearization state feedback control with hysteresis reference reformer to improve the dynamic response of interior permanent magnet synchronous motors.

Interior Permanent Magnet Synchronous Motors (IPMSMs) offer excellent features, however, the dynamic complexity of these motors has always caused a challenge to control them. In addition, Field Oriented Control (FOC) method developed using Proportional-Integral (PI) regulators, which is the most implemented approach to control the IPMSM, is associated with slow dynamic response and saturation in the controller. This paper presents a novel control algorithm based on State Feedback (SF) regulator for IPMSM drives. The focus of the paper is on simplifying the dynamic of the IPMSM using nonlinear analysis methods and enhancing the response of the designed control approach. The development of the control system starts with linearizing the dynamics of the IPMSM. A linearization approach based on Quadratic Linearization Method (QLM) is proposed and then the linear model is used for designing a state feedback controller optimized by Linear Quadratic Regulator (LQR) method. Applying control constraints is a challenge in systems controlled by state feedback theory. Hence, the proposed control method offers a novel solution based on hysteresis control theory. The proposed hysteresis technique offers several advantages such as lowering overshoot in speed step response in addition to applying constraints and it eliminates all drawbacks of hysteresis controllers. To control the IPMSM in the whole speed range (constant torque and constant power regions), the proposed approach adopts Maximum Torque per Ampere (MTPA) and Voltage Constraint Tracking (VCT) control strategies. Finally, simulations are carried out in MATLAB/SIMULINK environment to compare the performance of the proposed controller with the conventional FOC method.

Natural gas vaporization in a nanoscale throat connected model of shale: multi-scale, multi-component and multi-phase.

Production of hydrocarbons from shale is a complex process that necessitates the extraction of multi-component hydrocarbons trapped in multi-scale nanopores. While advances in nanofluidics have allowed researchers to probe thermodynamics and transport in single, discrete nanochannels, these studies present a highly simplified version of shale reservoirs with homogeneous pore structures and/or single-component fluid compositions. In this study, we develop and apply a 30 000-pore nanomodel that captures the inherent heterogeneity in reservoir pore sizes (100 nm pores gated by 5 nm-pores) to study vaporization of a representative natural gas hydrocarbon mixture. The nanomodel matches major North American formations in the volumetric and number contributions of the pore sizes, porosity (10.5%), and ultra-low permeability (44 nD). Combined experimental and analytical results show 3000× slower vaporization owing to the nanoscale throat bottlenecks. At low temperatures, mixture effects reduce rates further with stochastic vaporization of light components in large pores dominating. Collectively this approach captures the coupled complexity of multicomponent, multiphase fluids in multiscale geometries that is inherent to this resource.

Nanomodel visualization of fluid injections in tight formations.

The transport and phase change of a complex fluid mixture under nanoconfinement is of fundamental importance in nanoscience, and limits the recovery efficiency from tight oil reservoirs (<10%). Herein, through experiments and supporting theory we characterize the transport and phase change of a nanoconfined complex fluid mixture. Our nanofluidic platform, nanomodel, replicates shale reservoirs in terms of mean pore size (∼100 nm), permeability (∼µD) and porosity (∼10%). We screen conditions for the most promising shale EOR strategies, directly quantifying their pore-scale efficiency and underlying mechanisms. We find that immiscible gas (N2) flooding presents a prohibitively large capillary pressure threshold (∼2 MPa). Miscible (CO2) gas flooding eliminates this threshold leading to film-wise stable oil displacement with high recovery efficiency. Strong capillary forces present barriers as well as opportunities for recovery strategies unique to nanoporous reservoirs by transitioning from a miscible to an immiscible condition locally within the reservoir. These results quantify the fundamental transport and phase change mechanisms applicable to nanoconfined complex fluids, with direct implications in unconventional oil as well as nanoporous media more broadly.

Disposable silicon-glass microfluidic devices: precise, robust and cheap.

Si-glass microfluidics have long provided unprecedented precision, robustness and optical clarity. However, chip fabrication is costly (∼500 USD per chip) and in practice, devices are not heavily reused. We present a method to reduce the cost-per-chip by two orders of magnitude (∼5 USD per chip), rendering Si-glass microfluidics disposable for many applications. The strategy is based on reducing the area of the chip and a whole-chip manifolding strategy that achieves reliable high-pressure high-temperature fluid connectivity. The resulting system was validated at 130 bar and 95 °C and demonstrated in both energy and carbon capture applications. We studied heavy oil flooding with brine, polymer, and surfactant polymer solutions and found the surfactant polymer as the most effective solution which recovered ∼80% of the oil with the least amount of injection while maintaining a relatively uniform displacement front. In a carbon capture application, we measured the dilation of an emerging ionic liquid analog, choline chloride with urea, in gaseous and supercritical CO2. Previously restricted to niche microfluidic applications, the approach here brings the established benefits of Si-glass microfluidics to a broad range of applications.

Full Characterization of CO2-Oil Properties On-Chip: Solubility, Diffusivity, Extraction Pressure, Miscibility, and Contact Angle.

Carbon capture, storage, and utilization technologies target a reduction in net CO2 emissions to mitigate greenhouse gas effects. The largest such projects worldwide involve storing CO2 through enhanced oil recovery-a technologically and economically feasible approach that combines both storage and oil recovery. Successful implementation relies on detailed measurements of CO2-oil properties at relevant reservoir conditions (P = 2.0-13.0 MPa and T = 23 and 50 °C). In this paper, we demonstrate a microfluidic method to quantify the comprehensive suite of mutual properties of a CO2 and crude oil mixture including solubility, diffusivity, extraction pressure, minimum miscibility pressure (MMP), and contact angle. The time-lapse oil swelling/extraction in response to CO2 exposure under stepwise increasing pressure was quantified via fluorescence microscopy, using the inherent fluorescence property of the oil. The CO2 solubilities and diffusion coefficients were determined from the swelling process with measurements in strong agreement with previous results. The CO2-oil MMP was determined from the subsequent oil extraction process with measurements within 5% of previous values. In addition, the oil-CO2-silicon contact angle was measured throughout the process, with contact angle increasing with pressure. In contrast with conventional methods, which require days and ∼500 mL of fluid sample, the approach here provides a comprehensive suite of measurements, 100-fold faster with less than 1 µL of sample, and an opportunity to better inform large-scale CO2 projects.

Investigation of (235)U, (226)Ra, (232)Th, (40)K, (137)Cs, and heavy metal concentrations in Anzali international wetland using high-resolution gamma-ray spectrometry and atomic absorption spectroscopy.

Measurements of natural radioactivity levels and heavy metals in sediment and soil samples of the Anzali international wetland were carried out by two HPGe-gamma ray spectrometry and atomic absorption spectroscopy techniques. The concentrations of (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs in sediment samples ranged between 1.05 ± 0.51-5.81 ± 0.61, 18.06 ± 0.63-33.36 ± .0.34, 17.57 ± 0.38-45.84 ± 6.23, 371.88 ± 6.36-652.28 ± 11.60, and 0.43 ± 0.06-63.35 ± 0.94 Bq/kg, while in the soil samples they vary between 2.36-5.97, 22.71-38.37, 29.27-42.89, 472.66-533, and 1.05-9.60 Bq/kg for (235)U, (226)Ra, (232)Th, (40)K, and (137)Cs, respectively. Present results are compared with the available literature data and also with the world average values. The radium equivalent activity was well below the defined limit of 370 Bq/kg. The external hazard indices were found to be less than 1, indicating a low dose. Heavy metal concentrations were found to decrease in order as Fe > Mn > Sr > Zn > Cu > Cr > Ni > Pb > Co > Cd. These measurements will serve as background reference levels for the Anzali wetland.

Retrospective study maxillofacial fractures epidemiology and treatment plans in Southeast of Iran

BACKGROUND: The epidemiology of facial injuries varies in different countries and geographic zones. Population concentration, lifestyle, cultural background, and socioeconomic status can affect the prevalence of maxillofacial injuries. Therefore, in this study, we evaluated the maxillofacial fractures epidemiology and treatment plans in hospitalized patients (2012-2014) which would be useful for better policy making strategies. MATERIAL AND METHODS: In this retrospective study, the medical records of 386 hospitalized patients were evaluated from the department of maxillofacial surgery at Bahonar Hospital of Kerman, Iran. The type and cause of fractures and treatment plans were recorded in a checklist. For data analysis, ANOVA, t-test, Chi-square, and Fisher's exact test were performed, using SPSS version 21. RESULTS: The majority of patients were male (76.5%). Most subjects were within the age range of 20-30 years. Fractures were mostly caused by accidents, particularly motorcycle accidents (MCAs), and the most common site of involvement was the mandible (parasymphysis). There was a significant association between the type of treatment and age. In fact, the age group of 16-59 years under went open reduction internal fixation (ORIF) more than other age groups (P=0.02). Also, a significant association was observed between gender and the occurrence of fractures (P=0.01). CONCLUSIONS: Considering the geographic and cultural indices of the evaluated population, it can be concluded that patients age and gender and trauma causes significantly affect the prevalence of maxillofacial traumas and fracture kinds and treatment plans

Retrospective study maxillofacial fractures epidemiology and treatment plans in Southeast of Iran.

BACKGROUND: The epidemiology of facial injuries varies in different countries and geographic zones. Population concentration, lifestyle, cultural background, and socioeconomic status can affect the prevalence of maxillofacial injuries. Therefore, in this study, we evaluated the maxillofacial fractures epidemiology and treatment plans in hospitalized patients (2012-2014) which would be useful for better policy making strategies. MATERIAL AND METHODS: In this retrospective study, the medical records of 386 hospitalized patients were evaluated from the department of maxillofacial surgery at Bahonar Hospital of Kerman, Iran. The type and cause of fractures and treatment plans were recorded in a checklist. For data analysis, ANOVA, t-test, Chi-square, and Fisher's exact test were performed, using SPSS version 21. RESULTS: The majority of patients were male (76.5%). Most subjects were within the age range of 20-30 years. Fractures were mostly caused by accidents, particularly motorcycle accidents (MCAs), and the most common site of involvement was the mandible (parasymphysis). There was a significant association between the type of treatment and age. In fact, the age group of 16-59 years under went open reduction internal fixation (ORIF) more than other age groups (P=0.02). Also, a significant association was observed between gender and the occurrence of fractures (P=0.01). CONCLUSIONS: Considering the geographic and cultural indices of the evaluated population, it can be concluded that patients age and gender and trauma causes significantly affect the prevalence of maxillofacial traumas and fracture kinds and treatment plans.

Effect of recycling activities on the heating value of solid waste: case study of the Greater Vancouver Regional District (Metro Vancouver).

Two main goals of the integrated solid waste management system (ISWMS) of Metro Vancouver (MV) include further recycling of waste and energy recovery via incineration of waste. These two very common goals, however, are not always compatible enough to fit in an ISWMS depending on waste characteristics and details of recycling programs. This study showed that recent recycling activities in MV have negatively affected the net heating value (NHV) of municipal solid waste (MSW) in this regional district. Results show that meeting MV's goal for additional recycling of MSW by 2015 will further reduce the NHV of waste, if additional recycling activities are solely focused on more extensive recycling of packaging materials (e.g. paper and plastic). It is concluded that 50% additional recycling of paper and plastic in MV will increase the overall recycling rate to 70% (as targeted by the MV for 2015) and result in more than 8% reduction in NHV of MSW. This reduction translates to up to 2.3 million Canadian dollar (CAD$) less revenue at a potential waste-to-energy (WTE) plant with 500 000 tonnes year(-1) capacity. Properly designed recycling programmes, however, can make this functional element of ISWMS compatible with green goals of energy recovery from waste. Herein an explanation of how communities can increase their recycling activities without affecting the feasibility of potential WTE projects is presented.