Modelling and diagnosis of solid oxide fuel cell (SOFC)

The development of mathematical models and numerical simulations is crucial to design improvement, optimization, and control of solid oxide fuel cells (SOFCs). The current study introduces a novel and computationally efficient pseudo-two-dimensional (pseudo-2D) model for simulating a single cell of a high-temperature hydrogen-fueled SOFC. The simplified pseudo-2D model can evaluate the cell polarization curve, species concentrations along the channel, cell temperature, and the current density distribution. The model takes the cell voltage as an input and computes the total current as an output. A full-physics three-dimensional model is then developed in ANSYS Fluent, with a complete step-by-step modeling approach being explained, to study the same cell with the identical operating conditions. The 3D model is validated against the other numerical and experimental studies available in the literature. It is shown that although the pseudo-2D solution converges significantly faster in comparison with the 3D case, the results of both models thoroughly match especially for the case of species distributions. The simplified model was then used to conduct sensitivity analysis of the effects of multi-physiochemical properties of porous electrodes on the polarization curve of the cell. A systematic inverse approach was then used to estimate the mentioned properties by applying the pattern search optimization algorithm to the polarization curve found by the pseudo-2D model. Finally, nine different input parameters of the model were changed to find the hydrogen distribution for each case, and a huge dataset of nearly half a million operating points was generated. The data was successfully employed to design a novel classifier-regressor pair as a virtual hydrogen sensor for online tracking of hydrogen concentration along the cell to avoid fuel starvation

Survey of Factors that Affect the Arteriovenous Fistulas Survival in Semnan and Mahdishahr, Iran

Background: First step in chronic dialysis is establishing a suitable dialysis access. Arteriovenous fistula (AVF) has been known as the gold standard for hemodialysis; and due to complex interaction of factors that affect thesurvival time of fistula, we decided to evaluate survival time and affective factors among the dialysis patients.Methods: In a historical cohort study, we analyzed 52 patients of the Semnan and Mahdishahr Dialysis Centers. The data recorded by history taking and physical examination.Results: The survival of fistula was 83%, 80%, 67%, and 40% after 1, 3, 5, and 10 years respectively. Our results showed that the survival time of fistula was higher among patients with left-side AVFs. Factors such asage, gender, underlying disease, dialysis session per week, the time that patients started dialysis after installing fistula and fistula infection did not statistical significant affect the survival time.Conclusions: The survival time of AVF among dialysis patients of Semnan and Mahdishahr is satisfying, and installing the fistula in left hand lead to higher survival

Modification of nano-clays with ionic liquids for the removal of Cd (II) ion from aqueous phase

The present study attempts to synthesize nano-modified clays of Na-bentonite (Bent) and montmorillonite (MT), using three imidazolium-based ionic liquids (ILs) including 3,3′-(hexyl)bis(3-methylimidazolium) bromide chloride ([H(mim)2[Br][Cl]), 1-hexyl-3-methylimidazolium chloride ([Hmim][Cl]) and 1-octyl-3-methylimidazolium chloride ([Omim][Cl]). X-ray diffraction (XRD), Fourier transformed infrared spectroscopy (FT-IR), carbon, hydrogen and nitrogen elemental analysis (CHN), scanning electron microscope (SEM) and specific surface area (SSA) (using N2-BET) techniques provided evidence of successful modification of the guest clays. Removal of Cd (II) from aqueous phase was investigated using the modified clays under different experimental conditions of reaction time, pH and adsorbent dosage. Detailed isotherms and kinetic studies showed that the modified clays have much higher Cd (II) adsorption capacity compared to those of the starting clay minerals. The maximum Cd (II) absorption capacities of 87.46 and 94.6 mg g−1 were observed in [H(mim)2]-MT and [H(mim)2]-Bent with d-values of 35.4 Å and 28.3 Å respectively. The [Omim]-clays had the highest adsorption affinities of Cd (II) in initial concentrations of Cd (II). This study shows that ILs could enhance the clay capacity and tendency for Cd (II) absorption with different trends based on the ILs structures. The modified clays using ILs are green and eco-friendly adsorbents and due to substantial increase in their capacity for the removal of heavy metals, they could have positive economic and environmental impacts

The Relationship between Types of Delivery and Methods of Anesthesia with Occurrence of Jaundice in Term Neonates

Background Because of severe adverse effects of hyperbilirubinemia on newborns central nervous system diagnosis of its risk factors before delivery can prevent these effects.  This study aimed to determine the relationship between types of delivery with jaundice during the first week of life in Term neonates. Materials and Methods In this retrospective study, all term neonates born in Amiralmoemenin Hospital, Semnan, Iran, in 2016 were included into the study. Required data were collected including age, weight, type of delivery, gender, incidence of non-pathological jaundice and type of anesthesia in cesarean delivery using data recorded in the labor ward, hospital archives, and medical records of infants and recorded in a researcher made questionnaire. Results: Mean age of neonates was 40 ± 2 weeks and their mean weight was 3100 ± 200 grams. Among them, 48.8% of neonates with normal delivery and 49.1% of neonates with cesarean delivery were girls. Both groups did not have a significant difference in term of age, weight and gender (P > 0.05). In girls, there was no significant difference between type of delivery and hospitalization due to icterus (P=0.56). As the same in boys there was no significant difference between type of delivery and hospitalization due to icterus (P=0.059). Also, there was no difference in all neonates regardless of their sexuality, between type of delivery and hospitalization due to icterus (P=0.078). In cesarean delivery there was no significant difference in icterus severity between general and epidural anesthesia (P= 0.21). Conclusion The results indicate that cesarean delivery was not a risk factor for hospitalization due to icterus during first week after delivery. Further studies are recommended to confirm our results

Estimation of Short-term Mortality and Morbidity Attributed to Fine Particulate Matter in the Ambient Air of Eight Iranian Cities

Amongst the various pollutants in the air, particulate matters (PM) have significant adverse effects on human health. The current research is based on existing epidemiological literature for quantitative estimation of the current health impacts related to particulate matters in some selected principal Iranian megacities. In order to find the influence of air pollution on human health, we used the AirQ software tool presented by the World Health Organization (WHO) European Centre for Environment and Health (ECEH), Bilthoven Division. The adverse health outcomes used in the study consist of mortality (all causes excluding accidental causes), due to cardiovascular (CVD) and respiratory (RES) diseases, and morbidity (hospital admissions for CVD and RES causes). For this purpose, hourly PM10 data were taken from the monitoring stations in eight study cities during 2011 and 2012. Results showed annual average concentrations of PM10 and PM2.5 in all megacities exceeded national and international air quality standards and even reached levels nearly ten times higher than WHO guidelines in some cities. Considering the short-term effects, PM2.5 had the maximum effects on the health of the 19,048,000 residents of the eight Iranian cities, causing total mortality of 5,670 out of 87,907 during a one-year time-period. Hence, reducing concentrations and controlling air pollution, particularly the presence of particles, is urgent in these metropolises

Multi-messenger observations of a binary neutron star merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 Mo. An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ~40 Mpc) less than 11 hours after the merger by the One- Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ~10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ~9 and ~16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta

Multi-messenger Observations of a Binary Neutron Star Merger

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ∼ 1.7 {{s}} with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of {40}-8+8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in the range 0.86 to 2.26 {M}ȯ . An extensive observing campaign was launched across the electromagnetic spectrum leading to the discovery of a bright optical transient (SSS17a, now with the IAU identification of AT 2017gfo) in NGC 4993 (at ∼ 40 {{Mpc}}) less than 11 hours after the merger by the One-Meter, Two Hemisphere (1M2H) team using the 1 m Swope Telescope. The optical transient was independently detected by multiple teams within an hour. Subsequent observations targeted the object and its environment. Early ultraviolet observations revealed a blue transient that faded within 48 hours. Optical and infrared observations showed a redward evolution over ∼10 days. Following early non-detections, X-ray and radio emission were discovered at the transient’s position ∼ 9 and ∼ 16 days, respectively, after the merger. Both the X-ray and radio emission likely arise from a physical process that is distinct from the one that generates the UV/optical/near-infrared emission. No ultra-high-energy gamma-rays and no neutrino candidates consistent with the source were found in follow-up searches. These observations support the hypothesis that GW170817 was produced by the merger of two neutron stars in NGC 4993 followed by a short gamma-ray burst (GRB 170817A) and a kilonova/macronova powered by the radioactive decay of r-process nuclei synthesized in the ejecta.</p

Effect of Oxygen Plasma Pre-Treatment on the Surface Properties of Si-Modified Cotton Membranes for Oil/Water Separations

Hydrophobic and oleophilic Si-based cotton fabrics have recently gained a lot of attention in oil/water separation due to their high efficiency. In this study, we present the effect of O2 plasma pre-treatment on the final properties of two Si-based cotton membranes obtained from dip coating and plasma polymerization, using polydimethylsiloxane (PDMS) as starting polymeric precursor. The structural characterizations indicate the presence of Si bond on both the modified cotton surfaces, with an increase of the carbon bond, assuring the success in surface modification. On the other hand, employing O2 plasma strongly changes the cotton morphology, inducing specific roughness and affecting the hydrophobicity durability and separation efficiency. In particular, the wettability has been retained after 20 laundry tests at 40 °C and 80 °C, and, for separation efficiency, even after 30 cycles, an improvement in the range of 10–15%, both at room temperature and at 90 °C can be observed. These results clearly demonstrate that O2 plasma pre-treatment, an eco-friendly, non-toxic, solvent-free, and one-step method for inducing specific functionalities on surfaces, is very effective in enhancing the oil/water separation properties for Si-based cotton membranes, especially in combination with plasma polymerization procedure for Si-based deposition

Forecasting soil temperature at multiple-depth with a hybrid artificial neural network model coupled-hybrid firefly optimizer algorithm

Forecasting soil temperature at multiple depths is considered to be a core decision-making task for examining future changes in surface and sub-surface meteorological processes, land–atmosphere energy exchange, resilient agricultural systems for improved crop health and eco-environmental risk assessment. The aim of this paper is to estimate monthly soil temperature (ST) at multiple depth: 5, 10, 20, 50 and 100 cm with a hybrid multi-layer perceptron algorithm integrated with the firefly optimizer algorithm (MLP-FFA). To develop the hybrid MLP-FFA model, the monthly ST and relevant meteorological variables for the city of Adana (Turkey) are collated for the period of 2000–2007. Construction of hybrid MLP-FFA model is drawn upon a limited set of predictors, denoted as soil depth, periodicity (or the respective month), air temperature, pressure and solar radiation, while the objective variable for MLP-FFA model is the forecasted ST at multiple depths. To the evaluate MLP-FFA, statistical metrics applied to test the model’s performance are: the root mean square error (RMSE), mean absolute error (MAE), mean absolute percentage error (MAPE) and mean bias error (MBE) where the sign of the difference is also considered. In conjunction with statistical metrics, a Taylor diagram is utilized to visualize the degree of similarity between the observed and forecasted soil moisture. In terms of the forecasted results, the hybrid MLP-FFA model is seen to outperform the standalone MLP model. The optimal MLP-FFA is attained for soil temperature forecasting at a depth of 20 cm (RMSE, MAPE of 0.546 °C, 2.40%) whereas the optimal MLP is attained for soil temperature forecasting at a depth of 50 cm (RMSE of 0.544 °C, 2.21%). Conclusively, the study advocates through statistical metrics attained the better utility of the hybrid MLP-FFA hybrid model. Given its superior performance, it is ascertained that the hybrid MLP model integrated with Firefly optimizer is a qualified ancillary tool that can be applied to generate precise soil temperature forecasts at multiple soil depths. Keywords: Artificial neural network, Hybrid firefly algorithm, Soil temperature, Turkish State Meteorological Servic