230 research outputs found
Study the Effect of Seeding Suspension Concentration of DD3R Particles on the Modified Surface of Α-Alumina Support for Preparing DD3R Zeolite Membrane with High Quality
In this study, seeding of DD3R particles as an important step in the synthesis of DD3R membrane with secondary growth method was investigated. Dip-coating method is used for seeding of DD3R particles on the modified surface of α-alumina supports. 0.1, 0.2 and 0.3 wt% aqueous suspensions of the DD3R seeds were prepared and each support was coated three times with dipping time of 240 s. Scanning electron microscopy (SEM) analysis was used for the investigation of the quality of seed layer formed on the support. It is shown that the uniform layer of seeds was formed with 0.2 wt% seed suspension concentration. DD3R zeolite membrane was synthesized via hydrothermal method on the support seeded with 0.2 wt% seed suspension concentration. The X-ray diffraction and SEM analysis confirmed the synthesis of uniform DD3R zeolite membrane layer on the support which can be due to the uniform distribution of the DD3R seeds. Single gas permeation tests of N2, CO2 and CH4 were carried out, so that good perm-selectivity for gas mixtures was observed
Integrating Resilience into Risk Matrices: A Practical Approach to Risk Assessment with Empirical Analysis
The changing and intensifying landscape of global, national, and local disaster risks, driven by socio-political, environmental, and technological shifts, underscores the critical need for risk assessment by international agencies and governments. The Risk Matrix, introduced in 1995, has been widely used for risk assessment in different contexts, lauded for its simplicity and effectiveness. This model relies on the core risk components of consequence and likelihood, making it a favored tool for risk managers. To enhance the precision of risk assessment, various adaptations and extensions of the risk matrix have emerged; while some indirectly address resilience aspects, none explicitly integrate resilience into the matrix. This paper explores the risk matrix and its extensions, advocating for the inclusion of resilience in risk assessment. It introduces an empirical approach to quantify resilience, through a survey targeting small and medium-sized businesses in Southern Ontario, Canada. By developing two types of risk matrices—one with resilience considerations and one without—our work demonstrates how resilience alters risk prioritization, highlighting the importance of preparedness. This research underscores the pivotal role of resilience in risk assessment and urges its explicit integration into risk matrices to enhance accuracy and efficacy. Through practical examples and empirical data, the paper builds a compelling case for the central role of resilience in modern risk assessment practices
Are We Prepared for the Next Disaster? Evidence from Ice Storm
This study examines the impacts that an emergency had on people’s preparedness levels, using the December 2013 Ice Storm in the Greater Toronto Area (GTA) as a case. A questionnaire consisting of three sections was developed to measure the associated impacts, people’s reactions/opinions, as well as their preparedness levels before and after the ice storm. The goal of the research is not only to discuss the factors that influenced people’s ability to prepare, respond to and recover from the ice storm but also to generate useful insights for future disasters that are similar in nature. Our analysis includes various aspects such as the effectiveness of advance warnings and their ability to disseminate information to mass audiences. The findings show that, most of the respondents believe that they learned a lot about ice storms and their impacts because of their prior experience; a significant majority believe that it is the city’s/municipality’s responsibility to prepare for emergencies like ice storms; home ownership was significantly associated with the previous ice storm preparedness; and, power outage experience was significantly associated with the next ice storm preparedness
Short Term Omeprazole Use and Markers of Calcium Homeostasis
Introduction: Several studies indicate a higher prevalence of fracture following long term utilization of proton pump inhibitors, among them omeprazole is the most widely used. However, the exact mechanisms lead to this complication are largely unknown. We studied short term effects of omeprazole on some markers of calcium metabolism. Materials and Methods: In thirty young adult patients with gastroesophageal reflux, omeprazole was prescribed at 20 mg twice daily for thirty days. Baseline characteristics as well as data after treatment with omeprazole were compared. We also measure important parameters in sixty age and sex match healthy individuals at baseline. Results: Mean age of patients was 31.8 year and there was no significant difference regarding age, sex, body mass index, serum calcium, serum alkaline phosphatase, and parathyroid hormone between cases and controls. Although, most of the patients were vitamin D deficient (mean = 29.7 nmol/l); compared to controls serum 25 OH Vitamin D was higher (P= 0.005) and serum phosphate was lower (P= 0.001) in patients. In addition, there was significant increase in alkaline phosphatase (P=0.01) and borderline decrease in serum calcium (P= 0.057), thirty days after treatment with omeprazole. Conclusions: High dose omeprazole after thirty days in the presence of vitamin D deficiency affects bone turnover probably by decreasing calcium absorption
CT-measured pulmonary artery diameter as an independent predictor of pulmonary hypertension in cystic fibrosis
Purpose: The role of computed tomography (CT) scan, as a promising prognostic imaging modality in cystic fibrosis(CF), has been widely investigated, focusing on parenchymal abnormalities. The aim of the present study was to evaluate the diagnostic performance of thoracic vascular parameters on CT to detect pulmonary hypertension (PH). Material and methods: CF patients who contemporaneously underwent CT and echocardiography were retrospectively enrolled. Baseline characteristics in addition to pulmonary artery diameter (PAD) and pulmonary to aortic (PA/A) ratio were compared between cohorts with and without PH, based on the results of echocardiography separately in paediatric patients (< 18) and adults (≥ 18). Results: Of a total 119 CF patients, 39 (32.8%) had PH (paediatric: 23/78, 29.5%, adult: 16/41, 39%). In paediatric CF patients, mean age, HCo3, PCo2, and pulmonary artery diameter (PAD) were significantly higher in the PH group compared to the non-PH group. Mean pulmo however, only PAD remained as the independent predictor of PH based on multivariate analysis (overall: 22.86 mm [±3.86] vs. 18.43 mm [±4.72], p = 0.005, paediatric patients: 22.63 mm [±4.4] vs. 17.10 mm [±4.64], p = 0.03). Using a cut off of 19.25 mm, the diagnostic performance of PAD to detect PH was found to be as follows: sensitivity = 82%, specificity = 70%, and accuracy = 73.1%. No significant difference was demonstrated in PAD between PH and non-PH groups in adults with CF (23.19 [±3.60] vs. 21.34 [±3.49], p = 0.7). Conclusions: In CF patients, PAD revealed an age-dependent performance to detect PH. PAD can be applied to predict pulmonary hypertension in paediatric CF patients and may be recommended to be routinely measured on follow-up chest CT scan in childhood CF
A comparative study of genotoxicity and oxidative stress before and after using lemon balm and cinnamon in subjects exposed to Nickel Welding Fumes
    By producing reactive oxygen and nitrogen species, metal-induced toxicity and carcinogenicity alter DNA bases, increase lipid peroxidation, and change calcium and sulfhydryl homeostasis. The purpose of the study was to investigate putative effects of Lemon balm and Cinnamomum zeylanicum on the blood markers of welding workers. We measured nickel and chromium levels, biochemical parameters, blood oxidative stress markers, total antioxidant capacity (TAC), Myeloperoxidase (MPO), lipid peroxidation (LPO), and DNA damage. The study was conducted on 55 male workers who worked in an industrial subjects exposed to Nickel Welding Fumes. The participants were administered Lemon balm and Cinnamon extract infusion 1.5 (0.12 extract) and 0.25(0.013 extract) g/100 mL, respectively, they have drunken twice a day for 30 days at 7:00 AM and 2:00 PM every day. In order to analyze the achieved data, paired t-test and Pearson correlation coefficient have been used. After using the extract infusion, a significant increase revealed in TAC (p= 0.007). Also, administration of infusion decreased DNA damage but it was not statistically significant. After administration of infusion, a decrease in LPO and MPO were observed (p= 0.014, p=0.000 respectively). Also there is positive correlation between ALP and Ni with 8-oH-dG and also, between Ni and TAC. The results indicate that using infusion causes to raise in a TAC and reduce in DNA damage
Numerical Investigation on the Effect of Composite Corrugated Cores in Lightweight Sandwich Panels under Planar Impact Loading
Lightweight sandwich structural components have been widely used in different industries as highly effective energy absorbers. This research aims to provide a comparative study on the role of the composite corrugated sheet as a core in sandwich panels under low velocity impact loading. To reach this goal, the crashworthiness characteristics of three sandwich panels with different corrugated cores, which consist of identical mass and mechanical properties, are evaluated under vertical and transverse loading. The finite element computation is done using LS-DYNA under planar loading conditions. To validate the numerical process, first, the dynamic compression behavior of the square corrugated core sandwich panel made of aluminum alloys in comparison to existing experimental data is analyzed and the appropriate compliance has been observed. Then the effect of composite material and core shape on the crashworthy behavior of sandwich panels is explored. The research results reveal that the material type and geometric configuration of corrugated core have a considerable effect on the mean crushing load and the energy absorption of sandwich panels. It is found that the triangular configuration has a higher capability in load carrying and energy absorption than the square and/or the sinusoidal configuration. The failure modes of the crushed corrugated sandwich panels also significantly influenced by the type of corrugation cores. The present results supply valuable information on low velocity impact response that can be helpful for increasing crashworthy performance and development of such lightweight structures
Assessment of soil particle erodibility and sediment trapping using check dams in small semi-arid catchments
Check dams can be used as a source of information for studies on sediment characteristics and soil particle erodibility. In this study, sediment yield and grain size distribution (GSD) were measured in twenty small catchments draining into a rock check dam in NW Iran for different runoffs during 2010-2011. Significant correlations were found between sediment yield and slope steepness, vegetation cover and soil erodibility factor (K) of the catchments. The erodibility of soil particles was determined using the comparison of GSD between sediment and original soil. Clay was the most erodible soil particle which showed 2.05 times more percentage in sediment than the original soil. The erodibility of soil particles were strongly affected by the rainfall erosivity (EI30). Check dams showed more effectiveness in trapping coarse particles (sand and gravel). The effectiveness of check dams in trapping coarse particles enhanced with increase in the remaining capacity of check dams
Numerical Investigation on the Effect of Composite Corrugated Cores in Lightweight Sandwich Panels under Planar Impact Loading
Lightweight sandwich structural components have been widely used in different industries as highly effective energy absorbers. This research aims to provide a comparative study on the role of the composite corrugated sheet as a core in sandwich panels under low velocity impact loading. To reach this goal, the crashworthiness characteristics of three sandwich panels with different corrugated cores, which consist of identical mass and mechanical properties, are evaluated under vertical and transverse loading. The finite element computation is done using LS-DYNA under planar loading conditions. To validate the numerical process, first, the dynamic compression behavior of the square corrugated core sandwich panel made of aluminum alloys in comparison to existing experimental data is analyzed and the appropriate compliance has been observed. Then the effect of composite material and core shape on the crashworthy behavior of sandwich panels is explored. The research results reveal that the material type and geometric configuration of corrugated core have a considerable effect on the mean crushing load and the energy absorption of sandwich panels. It is found that the triangular configuration has a higher capability in load carrying and energy absorption than the square and/or the sinusoidal configuration. The failure modes of the crushed corrugated sandwich panels also significantly influenced by the type of corrugation cores. The present results supply valuable information on low velocity impact response that can be helpful for increasing crashworthy performance and development of such lightweight structures
Effect of Progressive Muscle Relaxation Technique on Fatigue in Patients Undergoing Hemodialysis
Background and Objectives: Fatigue is a common complaint among patients who undergo hemodialysis.
Fatigue influences their somatic, mental, sentimental and cognitive states. This study aimed to determine the
effect of progressive muscle relaxation technique on fatigue among patients treated with hemodialysis.
Materials and Methods: In this clinical trial, 90 patients undergoing hemodialysis were recruited from two
hemodialysis centers in Gonabad and Yazd and were randomly allocated into control (n=45) and trial (n=45)
groups. The progressive muscle relaxation technique was presented to the trial group during three sessions.
The patients were asked to make calm once a day for six weeks and at the end complete the relaxtion form.
No trainings were provided for the control group patients. The intensity of fatigue was compared between
the two groups. Data were collected using a questionnaire including demographic specifications, tools for
assessing the severity of fatigue and self-reported checklists. Data was analyzed using the statistical methods
in the SPSS.
Results: The results showed no significant differences in the level of fatigue between the two groups before
the intervention (p=0.12). There was significant difference in level of fatigue between the two groups after
the intervention (p<0.001). Conclusion: Using the progressive muscle relaxation technique is recommended for patients of the
hemodialysis ward
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