Comparison of artificial neural network and multivariate regression methods in prediction of soil cation exchange capacity (Case study: Ziaran region)

Investigation of soil properties like Cation Exchange Capacity (CEC) plays important roles in study of environmental reaserches as the spatial and temporal variability of this property have been led to development of indirect methods in estimation of this soil characteristic. Pedotransfer functions (PTFs) provide an alternative by estimating soil parameters from more readily available soil data. 70 soil samples were collected from different horizons of 15 soil profiles located in the Ziaran region, Qazvin province, Iran. Then, multivariate regression and neural network model (feed-forward back propagation network) were employed to develop a pedotransfer function for predicting soil parameter using easily measurable characteristics of clay and organic carbon. The performance of the multivariate regression and neural network model was evaluated using a test data set. In order to evaluate the models, root mean square error (RMSE) was used. The value of RMSE and R2 derived by ANN model for CEC were 0.47 and 0.94 respectively, while these parameters for multivariate regression model were 0.65 and 0.88 respectively. Results showed that artificial neural network with seven neurons in hidden layer had better performance in predicting soil cation exchange capacity than multivariate regression

Surficial and vertical distribution of heavy metals in marine and intertidal sediments in the Iranian sector of Gowatr bay

In order to identify natural and anthropogenic pollution in Gowatr bay (also gowadar bay), the distribution of heavy metals in the surface and different depths of marine and intertidal sediments was studied. For this purpose, 17 surficial sediment samples, and 5 sediment cores were collected, and compared with local background concentration. The results of surficial distribution of heavy metals indicate that maximum concentration of Copper and Zinc, Lead, and Nickel is related to Pasabandar harbor, sandy coast, and mudflats of Mangrove jungle, respectively. Calculated correlation coefficients indicate good positive correlation between Iron, clay fraction and potentially toxic metals, especially; Cu, Zn, Pb and Ni. Heavy metals distribution at depth was determined in five sediment cores. Sixty percent of sediment cores display surficial Pb enrichment, while Ni and Co are concentrated at depth. According to geo-accumulation factor (Igeo), zinc and copper show heavy contamination in Pasabandar harbor. Maximum PLI and RI are also related to Pasabandar harbor. Marine traffic, and ship yards activity at and close to Pasabandar harbor and mangrove jungle, along with weathering of ophiolites are apparently responsible for the observed elevated concentration of heavy metals in Gowatr bay

In-situ 3D measurements of water films on the natural grain surface of porous rocks

During fluid displacement, e.g. in aquifers or other fluid reservoirs such as CO2 or H2 storage sites or hydrocarbon reservoirs, water films are expected to form along the internal pore surface due to its wetting properties and capillarity. Near connate water saturation, these water films would dominate the macroscopic multiphase flow behaviour when e.g. water penetrates the porous medium. We use Atomic Force Microscopy (AFM) to study the sub-pore scale configuration of microscale water films on the rough pore surface of Ketton and Estaillades rocks, after drainage of the medium with decane. Then, we compare the results with a numerical simulation and use a film flow model to estimate the relative permeability through these films, which can be potentially used to link the water film configuration to pore- and core-scale responses. We find that the surface coverage and connectivity of the water films varies substantially with capillary pressure. This can affect the permeability of the films up to several orders of magnitude and thus potentially dictate the displacement efficiency at the onset of imbibition, when the brine phase re-enters the pore space. The novel experimental workflow proposed in this study may help future digital assessment of multiphase flow behaviour near connate saturation.</p

Microplastics in different tissues of fish and prawn from the Musa Estuary, Persian Gulf.

Commercially-important species of fish and a crustacean from four sites in the Musa estuary and a site in the Persian Gulf have been analysed for the presence and location of microplastics (MPs). A total of 828 MPs were detected in the guts (gastrointestinal tracts), skin, muscle, gills and liver of demersal and pelagic fish (Platycephalus indicus, Saurida tumbil, Sillago sihama, Cynoglossus abbreviatus) from all five sites and in the exoskeleton and muscle of the tiger prawn, Penaeus semisulcatus, from three sites. On an individual basis, MPs were most abundant in P. indicus (mean = 21.8) and least frequently encountered in P. semisulcatus (mean = 7.8), but when normalized on a mass basis, MPs ranged from 0.16 g-1 for C. abbreviatus to 1.5 g-1 for P. semisulcatus. Microscopic analyses (polarized light, fluorescence, SEM/EDS) revealed that MPs were mainly fibrous fragments (with a few angular fragments) of various colour and size ( 1000 μm) and with strong C and O signatures. Additional particles detected that were distinctly different in colour, morphology, brittleness and elemental composition (part-metallic, and containing Cu) were suspected of being fragments of antifouling paint. The means of entry of MPs into tissues not involved in digestion are unclear but could be related to translocation or adherence. Regardless of the mode of accumulation, the presence of MPs in heavily fished species of fish and crustacean raises concerns about the potential transfer of synthetic materials into humans

Accuracy of endoscopic ultrasonography for determination of tumor invasion depth in gastric cancer

Background: Gastric cancer (GC) is one the common lethal cancers in Iran. Detection of GC in the early stages would assesses to improve the survival of patients. In this study, we attempt to evaluate the accuracy of EUS in detection depth of invasion of GC among Iranian Patients. Materials and Methods: This study is a retrospective study of patients with pathologically confirmed GC. They underwent EUS before initiating the treatment. The accuracy of EUS and agreement between the two methods was evaluated by comparing pre treatment EUS finding with post operative histopathological results. Results: The overall accuracy of EUS for T and N staging was 67.9 and 75.47, respectively. Underestimation and overestimation was seen in 22 (14.2) and 40 (25.6) respectively. The EUS was more accurate in large tumors and the tumors located in the middle and lower parts of the stomach. The EUS was more sensitive in T3 staging. The values of weighted Kappa from the T and N staging were 0.53 and 0.66, respectively. Conclusions: EUS is a useful modality for evaluating the depth of invasion of GC. The accuracy of EUS was higher if the tumor was located in the lower parts of the stomach and the size of the tumor was more than 3 cm. Therefore, judgments made upon other criteria evaluated in this study need to be reconsidered

Lead-Free Perovskite-Inspired Absorbers for Indoor Photovoltaics

With the exponential rise in the market value and number of devices part of the Internet of Things (IoT), the demand for indoor photovoltaics (IPV) to power autonomous devices is predicted to rapidly increase. Lead-free perov skite-inspired materials (PIMs) have recently attracted significant attention in photovoltaics research, due to the similarity of their electronic structure to high-performance lead-halide perovskites, but without the same toxicity limitations. However, the capability of PIMs for indoor light harvesting has not yet been considered. Herein, two exemplar PIMs, BiOI and CsSbClxI-x are examined. It is shown that while their bandgaps are too wide for single-junction solar cells, they are close to the optimum for indoor light harvesting. As a result, while BiOI and CsSbClxI-x devices are only circa %-ecient under -sun illumination, their eciencies increase to –% under indoor illumination. These eciencies are within the range of reported values for hydrogenated amorphous silicon, i.e., the industry standard for IPV. It is demonstrated that such performance levels are already sucient for millimeter-scale PIM devices to power thin-film-transistor circuits. Intensity-dependent and optical loss analyses show that future improvements in eciency are possible. Furthermore, calculations of the optically limited eciency of these and other low-toxicity PIMs reveal their considerable potential for IPV, thus encouraging future eorts for their exploration for powering IoT devic

Salivary nitric oxide levels in adults with different DMFT scores in a selected iranian population: a cross-sectional study

Objectives: Due to the emphasis on the protective and antimicrobial role of Nitric Oxide against gas-trointestinal diseases, investigating its relationship with dental caries is a right topic. Therefore, this research has investigated the amount of saliva Nitric Oxide in different volumes of DMFT indicator in adults. Material and Methods: In this descriptive-analytical cross-sectional study, 80 participants (20-35 years old), without a history of systemic disease and drug use participated as research sam-ples, (53.8% of the participants in the study were women). Participants were selected from patients who had visited dental Department. The participants were divided in four groups based on DMFT (DMFT=0, 1≤DMFT≤3, 3&lt;10, DMFT≥10). Non-stimulating saliva was collected from all participants between 9-11 am in a calibrated tube. Saliva Nitric Oxide was measured using a Nitrous Oxide test, based on the Griess reaction. We used a correlation test to analyze quantitative variables, and t-test or ANOVA for qualitative and quantitative variables. Results: A significant relationship between DMFT and age was identified. At different levels of DMFT, significant relationship between DMFT and sex was not found. In different groups of DMFT, no significant relationship between Nitric Oxide and DMFT exist. Conclusion: The level of Nitric Oxide saliva was not affected by the amount of DMFT