238 research outputs found
Failures of Retaining Wall Structures Due to Earthquake
This paper describes crack pattern of reinforcement concrete retaining structure due to earthquake. For this reason, the 3-D finite element dynamic analysis of retaining wall structures with consideration of the soil-structure interaction has been used. Purpose of this study is to detect damage zone, due to earthquake in such structures. The analysis data is based on 1995 Kobe and 1994 Northridge earthquake reports, and the results have been verified with some retaining walls were damaged in those earthquakes. To take into account the non-linearity of soil-structure surface, surface to surface contact element is used. One of the most important problems in dynamic analysis is modeling of infinite media. If hinge or sliding support for soil boundary is used , it would not define an acceptable boundary condition, because the transmitted earthquake waves reflect from the boundary and no energy would transmit out. For simulation of the unbounded nature of the soil medium, viscous (dashpot) boundary has been applied. Damping coefficient is given by Lysmer and Kuhlemeyer, and Drucker Prager soil plasticity model is considered for non-linearity of soil. Distributions of the amplitude of stress in the wall, crack pattern in concrete wall are discussed in detail and finally suggested flexural failure diagram for determining damage zone and weak point of cantilever retaining wall
Fuzzy logic-based algorithm resource scheduling for improving the reliability of cloud computing
Cloud computing is an important infrastructure for distributed systems with the main objective of reducing the use
of resources. In a cloud environment, users may face thousands of resources to run each task. However, allocation
of resources to tasks by the user is an impossible endeavor. Accurate scheduling of system resources results in
their optimal use as well as an increase in the reliability of cloud computing. This study designed a system based
on fuzzy logic and followed by an introduction of an efficient and precise algorithm for scheduling resources for
improving the reliability of cloud computing. Waiting and turnaround times of the proposed method were
compared to those of previous works. In the proposed method, the waiting time is equal to 26.99 and the turnaround
time is equal to 82.99. According to the results, the proposed method outperforms other methods in terms of
waiting time and turnaround time as well as accuracy
Investigating the challenges of biodiversity management of Sefidkuh Khoramabad protected area by using the Delphi method
The main source of economic and agricultural development of all countries is natural resources. The dependency of local communities on natural resources and protected areas, and the excessive exploitation of forests and pastures and wildlife, has led to the destruction and degradation of biodiversity. The basis of managing protected areas in Iran is based on protection, research, training and entertaining, but in reality, protection is only limited to one fifth of these areas, which are safe. There is no management on the surrounding lands (the danger of islandization). Therefore, the purpose of this study is to identify and investigate the challenges of biodiversity management of Sefidkuh Khoramabad Protected Area by using Delphi method. This is a descriptive-analytic study. Thus, after identifying the available biodiversity and field visits and identifying the threats in the region, questionnaires were designed by experts regarding the Likert scale and were given to experts and specialists.The questions were answered by the experts and were analyzed by SPSS Software, the answers were prioritized by regression and descriptive analysis of existing threats and explained its relationship with four research variables (academic degree, familiarity with the region, job and employee of the organization). Then, this priority was organized as a questionnaire, and was given to the expert for final approval and identification of the main threats. Finally, some suggestions and recommendations are given.Keywords: Biodiversity, Challenges, Protected Areas, Sefidkouh, Prioritizatio
Development of an imperialist competitive algorithm (ICA)-based committee machine to predict bit penetration rate in oil wells of Iran
Drilling operation of a well is one the most expensive and time consuming procedures of oil and gas exploitation. Oil companies are always seeking for safe and cost-effective techniques for drilling. The main goal and motivation of drilling optimization is achieving the highest efficiency of work. Optimization and minimization of operational costs is one of the most important prerequisites of any engineering project. Rate of penetration is a crucial factor n drilling controlling cost and time of drilling. In the current research, capabilities of single independent intelligent models are employed for developing a hybrid committee machine that can predict bit penetration bit with high accuracy. To get this goal, three single intelligent models, including neural network, fuzzy logic and neuro-fuzzy, are trained. In the second step, the outputs of these models are integrated by imperialist competitive algorithm (ICA). Finally, a linear equation is achieved which gets outputs of single models as inputs and integrate them somehow the final results is closer to the actual value. The developed ICA-based committee machine is tested by 145 real data points gathered from the drilled wells in an oil field. Correlation of actual and predicted value of ROP obtained from committee machine shows that the model predicts ROP with accuracy of 88 percent. Such model can be used for optimization of drilling parameters in future drilling operations
Psychometric Properties of the Goals and Aspirations Inventory
This study aims to investigate the psychometric properties of the Goals and Aspirations inventory. In this applied study, a psychometric design was used and the statistical population consisted of students of Allameh Tabatabaei University during the academic year 2011–2012. Among the students of Allameh Tabatabai University, 250 people (115 girls, 135 boys) were selected through an available sampling method and answered the Aspirations Index (AI) and the Religious Orientation Scale (ROS). Validity and reliability, exploratory and confirmatory factor analysis were analyzed using SPSS-22 and Lisrel-8.8 software. The results of the first-order exploratory analysis confirmed the structure of the operational decade of goals and aspirations with 41 items in the Iranian youth population. In the second-order exploratory factor analysis, all ten subcomponents were classified into three indices: external, internal, and self-transcending aspirations. The results of the first and second level confirmatory factor analysis confirmed the good fit of the model and also the convergent validity of the questionnaire. Cronbach's alpha ranged from 0.77 to 0.86 for the components and was 0.90 for the intrinsic aspirations index, 0.90 for the external aspirations index, and 0.82 for the self-transcendence index. Therefore, researchers and educators can be suggested to use this questionnaire in research related to assigning goals and aspirations and, if necessary, use this instrument to provide a basis for reviewing adolescents' life goals
The Survey to Determine the Accuracy Rate of the Neoplasm Coding in Seyed Al-Shohada Hospital of Isfahan
Introduction: The use of cancer suffering patients' information is possible when this information was organized and categorized properly through encoding the diagnoses and therapeutic procedures. Therefore the aim of this study was to determine the accuracy rate of the neoplasm coding in Seyed Al-Shohada Hospital of Isfahan city in 2011.
Method: This study was a descriptive and cross-sectional study. The population of this study were medical records created during the second half of 2011,308 ones of which were selected as sample. A self-designed checklist was the research tool, which was used after validation. Data analysis was performed using SPSS v16. Software through descriptive statistics.
Results: Investigating the surveyed records, the researchers found that the accuracy rate of the records in this hospital was 68%. Also the highest accuracy rate of the coding has been associated with neoplasms of the connective tissue (94%).
Conclusion: Regarding the obtained results, it is recommended that coding of morphology & related Z codes of neoplasms be set in coders' work order. It is also recommended that continuous educational coding courses be held in order to increase the accuracy rate of the neoplasm coding
Measuring reliability of aspect-oriented software using a combination of artificial neural network and imperialist competitive algorithm
Aspect-oriented software engineering provides new ways to produce and deliver products and ultimately leads to reliable software. Reliability is an important issue contributing to the quality of software. Thus, software engineers need proven mechanisms to determine the extent of software reliability. In this paper, a method for measuring reliability is proposed which takes advantage of a Multilayer Perceptron Artificial Neural Network (MLPANN). Furthermore, an Imperialist Competitive Algorithm (ICA) is used to optimize the weights to improve network performance. Finally, relying on Root Mean Square Error (RMSE), the proposed approach is compared to a hybrid Genetic Algorithm- Artificial Neural Network (GA-ANN) method. The results show that the proposed approach exhibits lower error
An investigation of the morphological, thermal, mechanical, and barrier properties of an active packaging containing micro- and nano-sized ZnO particles
Biodegradable films are extremely important for food packaging applications since they minimize environmental effects. However, their application areas are limited due to insufficient characteristics required for particular applications. The objective of the present research was to improve the properties of sago-based biodegradable films embedded with nano- and micro-ZnO (zinc oxide). Nano and micro-ZnO were incorporated in the films at different percentages (1%, 3%, and 5%) in that the films were formed using the solvent casting method. The physicochemical, barrier, thermal, optical, morphology, and mechanical properties of sago-based films were investigated. Adding 5% of micro- and nano-ZnO significantly improved film thickness (0.162 and 0.150 mm, respectively) and WVP (4.40 and 5.64 (kg/s)/(m.Pa), respectively) while the optical properties and thermal stability exhibited superior performance. Micro-ZnO particles improved the mechanical properties of sago-based biodegradable films with the tensile strength reaching 6.173 MPa. Moreover, sago-based nano-ZnO films showed excellent UV-shielding performance and relatively good visible-light transmittance. This study suggested that sago biodegradable film incorporated with micro-ZnO could be an excellent alternative to petroleum-based plastic packaging
Increasing Vase Life of Cut Gerbera cv. Rosalin Flowers Using Nanocomposites as Preservative Solution
Introduction
Gerbera is one of the most important cut flowers that has a short vase life. Like other cut flowers, one of the main concerns after harvesting this flower is reducing its quality. The application of carbon nanotubes as preservative solutions increase water uptake, balances water relations, and increases the vase life of cut flowers. Agglomeration, lack of proper dispersion, and severe hydrophobicity are the disadvantages of carbon nanotubes that prevent optimal dispersion in the solution. In this study, polymers (polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), and non-ionic surfactant Triton X-100) were used to increase the dispersion of multiwalled carbon nanotubes (MWCNTs). Their effect on the longevity of cut gerbera flowers was also investigated.
Materials and Methods
The experiment was performed as a factorial experiment in a completely randomized design with four replications. Gerbera (Gerbera jamesonii cv. Rosalin) flowers with fully opened ray florets were purchased. During transportation, each cut flower was covered individually with a cellophane sheet and was placed inside a box of paper to minimize water loss. Gerbera stems were placed in a vase solution as pulse treatment for 24h. Treatments included various concentrations of nanocomposite including control (distilled water), MWCNTs-PVP nanocomposite (1 and 2 mg L-1), MWCNTs-PEG nanocomposite (1 and 2 mg L-1), and MWCNTs-Triton X-100 nanocomposite (1 and 2 mg L-1). Distilled water was used for the control treatment. After the cut gerbera flowers underwent pulse treatment, they were placed individually into glass vases filled with distilled water. Throughout the experiment, the vase life, relative fresh weight, water uptake, relative water content of petals and stems, as well as the bacterial population at the end of the stem were measured.
Results and Discussion
The study showed that the MWCNTs-Triton X-100 with a concentration of 2 mg L-1 provided the longest vase life of cut flowers, with a duration of 22.5 days, which was an 8-day increase compared to the control. The other nanocomposites (MWCNTs-PVP and MWCNTs-PEG) also improved the longevity of the cut flowers compared to the control. The nanocomposites in the vase solution affected the relative fresh weight and water uptake of the cut stems. The study found that the water uptake pattern was similar to the fresh weight of the flower, and the water uptake capacity of the stem gradually decreased with time. The MWCNTs-Triton X-100 with a concentration of 1 mg L-1 resulted in the highest amount of water uptake. Cut flowers pulsed with this concentration exhibited the highest relative water content in both petals and stems. The application of MWCNTs-PEG nanocomposite (1 mg L-1) in vase solution increased the relative fresh weight of gerbera cut flowers. Our findings suggest that MWCNTs can increase water uptake, resulting in increased fresh weight in the cut stem. SEM analysis revealed that after the evaluation period, MWCNTs were detected in the stem of cut gerbera and deposited on the stem's internal surface. Our finding showed that the bacterial population at the end of the stem in control treatment during the vase life period was higher than the bacterial population at the end of the stem of flowers treated with MWCNTs-Triton X-100 treatment (2 mg L-1). Therefore, reducing bacterial blockages in the xylem vessels improves the water uptake and vase life of cut flowers.
Conclusion
When gerbera cut flowers are harvested and kept in vase solutions, they face some challenges including wounding and water stress. Continuity of water flow in cut flower stem after cutting is an important factor in determining postharvest quality and longevity of cut flowers. Applying a solution containing well-dispersed MWCNTs is a novel approach for facilitating the entry of this nanotube into plants. The use of a composite of MWCNTs with X-100, PVP, and PEG exhibits excellent dispersion properties in the aqueous media of vase solution. These nanocomposites were successful compounds in increasing water uptake, maintaining fresh weight, and increasing the vase life of gerbera cut flowers. The findings of the present study showed that nanocomposites inhibit bacterial growth. These results suggest that the elimination of barriers to water flow in the cut stem helps to keep the longevity and delayed senescence
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