June 20, 1990 Earthquake of Northern Iran: An Overview

On the day of June 20, 1990 at 21:00 GMT (June 21, 1990, at 00:30 local time) a destructive earthquake of magnitude 7.6 shook Northern provinces of Iran. It caused widespread geotechnical and structural damages covering an approximate area of 10,000 sq. km resulting in 37,000 life losses, 100,000 injuries, and 100,000 building failures leaving more than 400,000 people homeless. This paper summarizes the post-earthquake investigations and discusses the general engineering aspects of the June 20, 1990 seismological, geotechnical, and structural aspects of the event. Lessons learned are also discussed

Development of a new poly silicate ferric coagulant and its application to coagulation-membrane filtration hybrid system in wastewater treatment

Coagulation is one of the effective pretreatment stages in membrane filtration of wastewaters to produce clean water. Using a suitable coagulant, one can mitigate membrane fouling. Membrane fouling is a process where particles deposit onto a membrane surface or into membrane pores in a way that degrades the membrane's performance. Research in this area is currently being focused on development of improved coagulation reagents such as poly silicate ferric (PSiFe), which has a high molecular weight and large number of positive surface charges with high efficiency at low doses. In this paper, PSiFe was prepared by following two approaches: (a) acidification of water glass solution using HCl followed by FeCl3 addition (old-PSiFe); (b) acidification of water glass solution by passing it through an acidic ion exchange resin followed by fresh FeCl3 addition under different Fe/Si molar ratios (new-PSiFe). These coagulants were characterised by X-ray diffraction and scanning electron microscopy. According to coagulation jar test results when Fe/Si = 1, the best performance was achieved in terms of turbidity, total organic carbon (TOC) and UV254 removals. Another aspect is the comparison of the old-PSiFe, FeCl3 and new-PSiFe which showed that in a membrane filtration system, using the new-PSiFe not only reduces the required transmembrane pressure (TMP) due to lower fouling, but also improves the TOC removal efficiency. © 2013 © 2013 Balaban Desalination Publications. All rights reserved

The Crack Development Due to Liquefaction of Sand Lenses During Earthquake Loading

The failure of sand lenses during earthquake loadings has caused many damages to the ground and yet its mechanism has not been investigated extensively. In this paper the results of an analytical studies involving the mechanism of crack development of a sand lens due to liquefaction, are presented. A single loose and saturated sand lens embedded inside a stiff clay deposit, which will liquefy due to the earthquake loading, is modeled by finite element method. The principles of fracture mechanics were used and the soil behavior was considered as a non-linear elasto-plastic material. The computer package of NISA was used and the failure mechanism of the lens was analysed by this package. Finally, the crack development and the angle of developed crack from the tip of the lens to the horizontal was calculated and discussed

Explaining National Trends in Terrestrial Water Storage

Access to fresh water is critical for human well-being, economic activity and, in some cases, political stability. Data from the Gravity Recovery and Climate Experiment (GRACE) has been used to monitor variability and trends in total water storage. This makes it possible to associate changes in water storage with both climate variability and large scale water management. Recent research has shown that these trends can be associated, globally, with rainfall, irrigation, and climate model predictions. This research indicates a need for further investigation into specific human predictors of trends in terrestrial water storage. This paper presents the first global scale analysis of GRACE trends focused on national scale socio-economic predictors of terrestrial water storage. We show that rainfall, irrigation, agricultural characteristics, and energy practices all contribute to GRACE trends, and the importance of each differs by country and region. Additionally, this work suggests that other factors such as GDP, population density, urbanization, and forest cover do not explain GRACE trends at a national level. Identifying these key predictors aids in understanding trends in water availability and for informing water management policy in a changing climate

Facile Design of Superparamagnetic Core-Shell EDC-Ascorbate-Fe3O4 Nanocomposites for Targeted Delivery of Doxorubicin to Triple Negative Breast Tumor by Fenton Reaction

Triple negative breast cancer (TNBC) phenotype accounts for its significant resistance to chemotherapy and other therapeutic procedures. So, the establishment of better and effective therapeutic procedures has become a challenge during recent years. Doxorubicin is a potent chemotherapeutic candidate but its prominent side effects can be subsided via its combination with nanocarriers. So, the present study was aimed to design ascorbic acid modified biopolymeric EDC/NHS-modified magnetic nanoparticles (MNP@MNP@AA-EDC/NHS-DOX for doxorubicin drug delivery to the triple negative breast cancers cell lines of MDA-MB-231, MDA-MB-468 and HCC1937. Monodisperse Fe3O4 MNPs were prepared by chemical co-precipitation method. According to the SEM and DLS results, MNP@AA-EDC/NHS-DOX, MNPs@AA, MNP@AA-MNP@AA-EDC/NHS and MNP@AA-EDC/NHS-DOX had average particle diameter of 53, 79 and 95 nm, respectively. While, XRD analysis showed that the MNP material had the strongest Fe crystal peak, while surface modified MNP@AA-EDC/NHS-DOX did not alter the characteristic properties of MNPs. VSM magnetization analysis revealed that MNP@AA-EDC/NHS-DOX exhibited sufficient paramagnetic potential in the presence of external magnetic field. The TG analysis showed that thermal decomposition capacity of present nanocomposites was: MNPs > MNP@AA-EDC/NHS > AA-MNPs > MNP@AA-EDC/NHS-DOX. AA-modified MNPs did not completely lose their thermal stability as compared to other modifications. Alamar blue analysis revealed that the bare MNPs did have non-significant cytotoxicity in MDA-MB-231, MDA-MB-468 and HCC1937 cell lines (p > 0.001). While, MNP@AA-EDC/NHS-DOX at 0.1, 1.0 and 10 μg/mL DOX concentrations showed significantly lowered cell survival percentages as compared to the free DOX regimens after 24 and 72h. While, HCC1937 cell line had the most accumulation of free (1.42 > 0.93 > 0.9 pg DOX/cell) and conjugated DOX (2.64 > 2.2 > 1.91 pg DOX/cell) after 6 h of incubation period as compared to MDA-MB-468 and MDA-MB-231, respectively (* p < 0.05). Present results provide a new insight into the design of paramagnetic targeted drug delivery nanocomposite system to overcome the obstacles and side effects of conventional chemotherapeutic agents

Content analysis of secondary school chemistry textbooks based on components of resistance economy: Shannon Entropy Methodod

Background and Objectives:The present study aims to analyze the content of second grade chemistry textbooks based on the emphasis on the goals of resistance economy. Methods: The research method in this study was descriptive content analysis. In this study, after collecting quantitative data, Shannon entropy technique was used for anarysis. The statistical population of this study formed the content of all secondary high school chemistry textbooks. The sampling method in this study was census; Therefore, all second grade chemistry textbooks were analyzed. The registration unit in this study was the subject. In this study, the frequency of components and themes of resistance economy in chemistry curricula were examined. Findings: The findings of the content analysis showed that in secondary high school chemistry books, the most attention was paid to the goals of resistance economy in the field of consumption the field of skills and the field of production attitude. Conclusion: From the present study, it can be concluded that in the second grade chemistry textbooks, very little attention has been paid to the goals of the resistance economy. Also, in secondary school chemistry curricula, little attention has been paid to the goals and components of the resistance economy and the amount of attention to the goals of the resistance economy do not have a normal distribution and only some components of the resistance economy in the second secondary school (three dimensions and three areas) are consi dered

Vulnerability of Smart Grid-enabled Protection Relays to IEMI

The electricity sector has been undergoing transformations towards the smart grid concept, which aims to improve the robustness, efficiency, and flexibility of the power system. This transition has been achieved by the introduction of smart electronic devices (SEDs) and advanced automatic control and communication systems. Despite the benefits of such modernization, safety issues have emerged with significant concern by experts and entities worldwide. One of these issues is known as Intentional Electromagnetic Interference (IEMI), where offenders employ high-power electromagnetic sources to maliciously disrupt or damage electronic devices. One of the possible gateways for IEMI attacks targeting the smart grids is the microprocessor-based protection relays. On the one hand, the malfunctioning of these devices can lead to equipment damage, including high-voltage equipment (e.g., power transformers), which represent one of the most high-cost items of energy infrastructure. On the other hand, a possible misleading triggering of these devices could cause cascading effects along the various nodes of the power system, resulting in widespread blackouts. Thus, this study presents the possible recurring effects of IEMI exposure of a typical protection relay used in smart grid substations as part of the SCADA (Supervisory Control and Data Acquisition) system. For this purpose, a test setup containing a smart grid protective unit, a monitoring box, and the device's wiring harness is exposed to radiated IEMI threats with high-power narrowband signals using a TEM waveguide and horn antennas. The effects during the test campaigns are observed by means of an IEMI-hardened camera system and a software developed to real-time monitor the device's fibre optic communication link, which is established according to the IEC 60870-5-105 protocol. The results revealed failures ranging from display deviation to various types of protection relay shutdown. Moreover, the consequences of the identified failures in a power substation are discussed to feed into a risk analysis regarding the threat of IEMI to power infrastructures.</p

A pilot double-blind randomised placebo-controlled trial of the effects of fixed-dose combination therapy ('polypill') on cardiovascular risk factors

SummaryAim: Our objective was to investigate the effects and tolerability of fixed-dose combination therapy on blood pressure and LDL in adults without elevated blood pressure or lipid levels. Methods: This was a double-blind randomised placebo-controlled trial in residents of Kalaleh, Golestan, Iran. Following an 8-week placebo run-in period, 475 participants, aged 50 to 79 years, without cardiovascular disease, hypertension or hyperlipidaemia were randomised to fixed-dose combination therapy with aspirin 81 mg, enalapril 2.5 mg, atorvastatin 20 mg and hydrochlorothiazide 12.5 mg (polypill) or placebo for a period of 12 months. The primary outcomes were changes in LDL-cholesterol, systolic and diastolic blood pressure and adverse reactions. Analysis was by intention-to-treat basis. Results: At baseline, there were differences in systolic blood pressure (6 mmHg). Taking account of baseline differences, at 12 months, polypill was associated with statistically significant reductions in blood pressure (4.5/1.6 mmHg) and LDL-cholesterol (0.46 mmol/l). The study drug was well tolerated, but resulted in the modest reductions in blood pressure and lipid levels. Conclusion: The effects of the polypill on blood pressure and lipid levels were less than anticipated, raising questions about the reliability of the reported compliance. There is a case for a fully powered trial of a polypill for the prevention of cardiovascular disease. © 2010 Blackwell Publishing Ltd

Static and vibration analysis of functionally graded beams using refined shear deformation theory

Static and vibration analysis of functionally graded beams using refined shear deformation theory is presented. The developed theory, which does not require shear correction factor, accounts for shear deformation effect and coupling coming from the material anisotropy. Governing equations of motion are derived from the Hamilton's principle. The resulting coupling is referred to as triply coupled axial-flexural response. A two-noded Hermite-cubic element with five degree-of-freedom per node is developed to solve the problem. Numerical results are obtained for functionally graded beams with simply-supported, cantilever-free and clamped-clamped boundary conditions to investigate effects of the power-law exponent and modulus ratio on the displacements, natural frequencies and corresponding mode shapes