Modeling the effects of high strain rate loading on RC columns using Arbitrary Lagrangian Eulerian (ALE) technique

In recent years, many studies have been conducted by governmental and nongovernmental organizations across the world in an attempt to better understand the effect of explosive loads on buildings in order to better design against specific threats. This study is intended to contribute to increase the knowledge about how explosions affect reinforced concrete (RC) columns. In this study, a nonlinear model is developed to study the blast response of RC columns subjected to explosive loads. Numerical modeling of RC column under explosive load is presented using advanced finite element code LS DYNA. The obtained numerical model is validated with the experimental test and the results are in substantial agreement with the experimental data. ALE method for blast analysis is presented in the current research. The effects of scaled distance on the damage profile of RC columns are investigated. The results demonstrate that the level of damage increased with describing the scaled distance. Also the results shown duration for the blast loading, and hence the impulse, varies with charge masses at the specified scaled distance. Higher magnitude charge masses produced longer blast loading durations than lower magnitude charge masses. This means that at the same scaled distance, a charge mass of higher magnitude produced a higher impulse than the lower magnitude charge mass. The findings of this research represent the scaled distance is an important parameter that should be taken into account when analyzing the behavior of RC columns under explosive effects. The data collected from this research are being used to improve the knowledge of how structures will respond to a blast event, and improve finite element models for predicting the blast performance of concrete structures.Peer Reviewe

Heavy metal flocculation at Pirbazar River, Banadar Anzali, south west Caspian Sea

Heavy metal flocculation process was studied in the year 2002 in order to determine the interaction of water in Pirbazar River with Caspian Sea water. The effects of various salinity concentrations of Caspian Sea water were studied on determined heavy metals including Fe, Zn, Pb, Cu, Cd and Cr level of Pirbazar River using APHA method of extraction and measurement. The results illustrated that the level of heavy metal concentration in Pirbazar River were above standard limits and the extent of flocculation depended on both the salinity level and the heavy metal itself. The maximum flocculation for Cd and Cr were recorded at 7.65ppt, for Zn and Fe at 9.35ppt while for Pb and Cd were at 2.55ppt salinity. The order of flocculation with respect to percentage of original concentrations was found to be Zn > Fe > Cr> Cu > Cd> Pb

Association between vitamin d deficiencies in sarcoidosis with disease activity, course of disease and stages of lung involvements

Background: Despite negative association between 25-hydroxy vitamin D and incidence of many chronic respiratory diseases, this feature was not well studied in sarcoidosis. Current study investigated the association between 25-hydroxy vitamin D deficiency with sarcoidosis chronicity, disease activity, extra-pulmonary skin manifestations, urine calcium level and pulmonary function status in Iranian sarcoidosis patients. Results of this study along with future studies, will supply more effective programs for sarcoidosis treatment. Methods: Eighty sarcoidosis patients in two groups of insufficient serum level and sufficient serum level of 25-hydroxy vitamin D were studied. Course of sarcoidosis was defined as acute and chronic sarcoidosis. Pulmonary function test (PFT) was assessed by spirometry. Skin involvements were defined as biopsy proven skin sarcoidosis. 24-hour urine calcium level was used to specify the disease activity. Stages of lung involvements were obtained by CT-scan and chest X-ray. The statistical analyses were evaluated using Statistical Package for the Social Sciences. Results: A significant negative correlation was obtained between vitamin D deficiency in sarcoidosis patients and disease chronic course and stages two to four of lung involvements. Considering other parameters of the disease and vitamin D deficiency, no significant correlation was detected. Conclusions: In conclusion, results of the current study implies in the role of vitamin 25(OH)D deficiencies in predicting the course of chronic sarcoidosis. Furthermore, it was concluded that vitamin 25(OH)D deficiency can direct pulmonary sarcoidosis toward stage 2–4 of lung involvements

A survey on surfactant concentration in southern Caspian Sea

We determined concentration of surfactants as mg/I of LAS using Sublation-Methylen Blue method in the south Caspian Sea coastal areas extending from Astara to Bandar-e-Tourkaman. The method was based on the American Standard Method for Examination of Water and Wastewater. We analyzed 53 water samples and found an average surfactant concentration of 0.019mgi1 with the minimum and maximum being 0.008mg/I and 0.038mgi1 respectively. We conclude that presently, surfactant concentration is not critical in the coastal areas. However, care must be exercised interpreting these results considering the synergistic effects between the surfactants and heavy metals and oil hydrocarbons

Propiedades tecnológicas de la madera de Citharexylum montevidense (Spreng.) Mol. “Espina de bañado”

Citharexylum montevidense (Spreng.) Mol “Espina de bañado” es una especie nativa empleada artesanalmente en carpintería, construcciones, postes y marcos para aberturas. Sin embargo, no existen estudios tecnológicos que caractericen sus cualidades maderables, los cuales podrían permitir revalorizar su madera hacia productos de mayor valor agregado. El objetivo del presente trabajo fue determinar las propiedades físicas y mecánicas de su madera con el propósito de identificar potenciales nuevos usos. Se determinaron: contenido de humedad, densidad normal, cambios dimensionales, dureza Janka y flexión estática. La densidad (0,68 g.$latex cm^{-3}$ +/- 1208,08). De acuerdo con los valores de dureza Janka hallados, puede considerarse a la madera de Espina de bañando como semidura. Los valores obtenidos en los parámetros físico mecánicos estudiados presumen un buen comportamiento de esta madera al secado, haciéndola apta para la fabricación de pisos, aberturas y muebles.Citharexylum montevidense (Spreng.)Mol a.k.a. “Marsh Thorn” is a native species used in craft carpentry, constructions, posts and door frames. However, there are no studies that characterize technological timber qualities, which could allow wood to revalue its higher value-added products. The aim of this work was to determine the physical and mechanical features of this wood in order to identify potential new uses. Thus water content, normal density, dimensional changes, Janka hardness and static bending were determined. Density values (0.68 g.$latex cm^{-3}$+/- 1208.08). According to the values found for the Janka hardness, the wood ofCitharexylum montevidense (Spreng.) Mol is a semi-hard one. All the values obtained for both the physical and mechanical parameters of this woodletits good behavior be assumed as to the drying process which makes it suitable for the making of floors, openings, and furniture

Correlation Between Intra-Abdominal Free Fluid and Solid Organ Injury in Blunt Abdominal Trauma

Background: In previous studies, the diagnostic value of Focused Assessment with Sonography for Trauma (FAST) has been evaluated but few studies have been performed on the relationship between the amount of free intra-abdominal fluid and organ injury in blunt abdominal trauma. To select patients with a higher probability of intra-abdominal injuries, several scoring systems have been proposed based on the results of FAST. Objectives: The aim of this study was to determine the prognostic value of FAST according to the Huang scoring system and to propose a cut-off point for predicting the presence of intra-abdominal injuries on the Computed Tomography (CT) scan. The correlation between age and Glasgow Coma Scale (GCS) and the presence of intra-abdominal injuries on the CT scan was also assessed. Patients and Methods: This study was performed on 200 patients with severe blunt abdominal trauma who had stable vital signs. For all patients, FAST-ultrasound was performed by a radiologist and the free fluid score in the abdomen was calculated according to the Huang score. Immediately, an intravenous contrast-enhanced abdominal CT scan was performed in all patients and abdominal solid organ injuries were assessed. Results were analyzed using Kruskal-Wallis test, Mann-Whitney test and ROC curves. The correlation between age and GCS and the presence of intra-abdominal injuries on CT-scan was also evaluated. Results: The mean age of the patients was 29.6 ± 18.3 years and FAST was positive in 67% of the subjects. A significant correlation was seen between the FAST score and the presence of organ injury on CT scan (P < 0.001). Considering the cut-off point of 3 for the free fluid score (with a range of 0-8), sensitivity, specificity, positive predictive value and negative predictive value were calculated to be 0.83, 0.98, 0.93, and 0.95, respectively. Age and GCS showed no significant correlation with intra-abdominal injuries. Conclusions: It seems that FAST examination for intra-abdominal fluid in blunt trauma patients can predict intra-abdominal injuries with very high sensitivity and specificity. Using the scoring system can more accurately determine the probability of the presence of abdominal injuries with a cut-off point of three