375 research outputs found
An Extended Weighted Exponential Distribution
A new class of weighted distributions is proposed by incorporating an extended exponential distribution in Azzalini’s (1985) method. Several statistics and reliability properties of this new class of distribution are obtained. Maximum likelihood estimators of the unknown parameters cannot be obtained in explicit forms; they have to be obtained by solving some numerical methods. Two data sets are analyzed for illustrative purposes, and show that the proposed model can be used effectively in analyzing real data
Eco-Friendly Asphalt Containing Recycled High-Density Polyethylene (HDPE): Performance Assessment and Cost Analysis
Utilization of the recycled waste materials for new products is considered as a viable solution for saving the environment. This study paper targets the performance evaluation of hot-mix asphalt made with the modified bitumen 60/70 containing 3% and 5% of recycled high-density polyethylene (HDPE) (by the weight of optimum bitumen). First, the properties of modified bitumen mixtures including specific density, penetration depth, ductility, and softening point were measured. Then, the properties of asphalt mixtures made with the modified bitumen including rutting depth and resilient modulus were measured. Findings indicated the suitability of recycled HDPE available in Iranian market in the development of eco-friendly asphalt mixtures. Results showed a 49% decrease in penetration depth and a 15% increase in softening point for the suggested modified bitumen mixture containing 3% of recycled HDPE compared to those of control bitumen mixture, i.e. the bitumen mixture containing 0% of recycled HDPE. Results also showed a 47% decrease in rutting depth and a 113% increase in resilient modulus of asphalt made with the bitumen mixture containing 3% of recycled HDPE compared to those of control asphalt mixture, i.e. the asphalt mixture containing 0% of recycled HDPE. The results showed that the suggested asphalt mixture can be an appropriate option to be adopted not only in moderate climates but also in tropical climates as its characteristics become comparable to those of the bitumen 40/50 and the bitumen 30/40. Replacing a portion of bitumen by the recycled HDPE not only improves the characteristics of asphalt, but also has a positive impact on reducing the natural resource depletion and environmental pollution resulting from burning and/or the retention of plastic waste left in nature. The suggested eco-friendly asphalt is also cost effective
Thermodynamic study of PCB-153 passing into single walled carbon nanotube (8,8)
Polychlorinated biphenyl (PCBs) are high resistant pollutants which cause adverse health effects in recent years. The accumulation of these toxic compounds in the food chain lead to oxidative stress in various ecosystems. Detection, absorption, and elimination of them are an environmental priority. Passing of PCB-153 through the armchair single walled carbon nanotube (SWNT) (8,8) were investigated by MNDO in semi-empirical quantum method. Calculated electrical and thermodynamic properties show a sudden change in the middle of the tube which may act as a trap for the studied pollutant. The results indicated the nanotube has considerable ability to interact with PCB-153 and cause its degradation. According to calculated thermodynamic parameters through the molecular modeling, it is expected that single wall carbon nanotube is a candidate in remediation of PCBs as well as in gas sensor devices for detection of them. The median tube is a place for trapping pollutants
Design and Performance of Microstrip Diplexers: A Review
The radiofrequency microstrip diplexers are widely demanded nowadays by modern wireless communication systems. Hence, several types of previously reported microstrip diplexers are reviewed and investigated in this work. Microstrip diplexers are three ports devices used for separating desired signals and delivering them through two (or more) different channels. The diplexers are investigated in three categories of dual-channel bandpass-bandpass diplexers, multichannel diplexers, and lowpassbandpass diplexers. The investigated multi-channel diplexers include a number of four-channel, six-channel, and eight-channel diplexers. Due to the hard design process, the number of reported diplexers with more than four channels is limited. The layout structures and theory design methods of the previously reported diplexers are studied. Moreover, their size and performance are compared while some explanations about their advantages and disadvantages are presented. This comparison includes insertion loss, return loss, fractional bandwidths, isolation, selectivity, and gaps between channels
Bayesian network model for flood forecasting based on atmospheric ensemble forecasts
The purpose of this study is to propose the Bayesian network (BN) model to estimate flood peaks from atmospheric ensemble forecasts (AEFs). The Weather Research and Forecasting (WRF) model was used to simulate historic storms using five cumulus parameterization schemes. The BN model was trained to compute flood peak forecasts from AEFs and hydrological pre-conditions. The mean absolute relative error was calculated as 0.076 for validation data. An artificial neural network (ANN) was applied for the same problem but showed inferior performance with a mean absolute relative error of 0.39. It seems that BN is less sensitive to small data sets, thus it is more suited for flood peak forecasting than ANN
Design and fabrication of a compact microstrip triplexer for wimax and wireless applications
A novel structure to design a microstrip triplexer for wireless and WiMAX applications is presented. To obtain a compact microstrip layout, step impedance resonators and coupled lines are used. The introduced triplexer has a size of 0.35λg×0.26λg, where λg is calculated at 2.3 GHz. Also, the obtained insertion losses are 0.78 dB, 1.1 dB and 0.62 dB at 2.3 GHz, 3.2 GHz and 3.6 GHz, respectively. The LC model of the presented resonator is investigated to tune three resonance frequencies by calculating numerical values of inductors and capacitors. Finally, the designed triplexer is simulated and measured
A Comparison of Apical Transportation in Severely Curved Canals Induced by Reciproc and BioRaCe Systems
Introduction: Preserving the apical root structure during cleaning and shaping of the canal has always been a challenge in endodontics particularly when the root canals are curved. The purpose of this in vitro study was to compare the apical transportation induced by the Reciproc and BioRaCe rotary systems in preparing the mesiobuccal root canal of the human maxillary molars. Materials and Methods: The mesiobuccal canals of sixty extracted maxillary molars with curvature angle of 25-35˚ were selected and randomly assigned into two groups. Each canal was prepared by either Reciproc or BioRaCe rotary systems. A double-digital radiographic technique and AutoCAD software were used to compare the apical transportation at 0.5, 1, 2, 3, 4 and 5 mm distances from the working length (WL). The distance between the master apical rotary file and the initial K-file in the superimposed radiographs determined the amount of apical transportation. An independent t-test was used to compare the groups. The statistical significant level was set at 0.05. Results: Apical transportation of the Reciproc group was significantly greater than the BioRaCe group in all distances (P<0.001). The maximum apical transportation occurred in the Reciproc group at 0.5 mm from the WL (0.048±0.0028 mm) and the minimum occurred for BioRaCe at 5 mm from the WL (0.010±0.0005 mm). Conclusions: The Reciproc system produced significantly more apical transportation than the BioRaCe, but this fact does not seem to negatively alter the clinical success or quality of root canal treatment
Investigating the effectiveness of blended learning in reading proficiency: Evidence from intermediate EFL learners
As an alternative solution to solve different reading comprehension problems in learning English as a foreign language (EFL), it is necessary to implement a blended learning model that combines both online and face-to-face (f2f) teaching modes. This study aimed at investigating the impact of blended learning on Iranian intermediate EFL learners’ reading proficiency. Sixty EFL learners were chosen based on their performance on Oxford Placement Test. Then, they were divided into two groups (an experimental and a control group). The experimental group received reading materials through blending learning techniques and the control group received training in the traditional way. During treatment, the teacher designed and assigned activities for students to read the text effectively and reinforce their comprehension. The activities were designed to teach reading like scanning, skimming, and reading for accurate comprehension. Afterward, both groups participated in the reading post-test at the end of the study. The results showed that the experimental group outperformed the control group in the post-test of reading comprehension and the intra-group progress was higher for the experimental group than the control group
Mutual Roles of Model-Driven Software Engineering and Low-Code Development Platform
In the last few years, we have witnessed a significant growth of "low-code development platforms" (LCDPs) in attracting the attention of both the market and the academia. LCDPs are visual development platforms that typically run on the cloud, reducing the need for manual coding. They are also used by non-professional developers with limited knowledge in programming to construct applications. In this paper, the characteristics of well-known LCDPs are first studied to evaluate the advantages of this approach. Given that the low-code platforms have many goals and features in common with the model-driven engineering (MDE) approaches, it is necessary to examine the position of these platforms in comparison with the MDE approaches and identify the strengths and weaknesses of both. One of the reasons for the popularity of the LCDP platforms is the use of cloud computing, which most model-driven engineering approaches have failed to achieve. Therefore, in this article, we review the solutions for using cloud computing in MDE to apply these approaches to develop low-code platforms and apply the approach on a modeling language for smart contracts
Public Eye toward COVID-19: A Systematic Review
BACKGROUND: The general public has an important role in controlling the spread of infectious diseases by pursuing prophylactic measures.
AIM: The aim of the present systematic review was to describe public perceptions, knowledge, attitudes, and behaviors toward COVID-19.
METHODS: In this review, articles were extracted from the Google Scholar, Embase, Scopus, Web of Science, and PubMed search engines. The main keywords for the search were coronavirus, COVID-19, public perceptions, knowledge, attitudes, and behaviors.
RESULTS: The knowledge level toward novel coronavirus in different countries was generally high, and it had an increasing pattern during the pandemic phase. Furthermore, the insight self-efficacy, perceived severity of the COVID-19, and intention to meet the needs of preventive measures have increased notably. Furthermore, there are several misconceptions and unconfirmed beliefs in the general public in the case of preventive measures recommended, in particular.
CONCLUSIONS: Health authorities and other disease control centers should monitor public misconceptions and perceptions continuously and manage a trusting platform to be presented to the public, especially in the case of a novel disease outbreak
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