Experimental modeling of orange settling depth in water

Settling depth of orange fruits and vegetables with the density lower than the density of water is an important hydrodynamic property important in hydraulic sorting and transporting. In this research, settling depth of orange fruit with regular shapes was experimentally modeled. The considered parameters in multivariate modeling were fruit characteristics, density, mass and volume, and dropping height of the fruits. The characteristics were determined by standard methods. The settling depth was determined by a water column and a digital camera. The models were obtained in MATLAB software. The best model was based on the density, volume and dropping height with coefficient of determination (R2) and mean squire error (MSE) of 0.89 and 4.67×10-7, respectively

A 40 Gb/s duty-cycle/polarization division multiplexing system

Ever increasing demand for higher bandwidth and capacity requests more efficient multiplexing techniques. To increase supportable subscribers in networks, hybrid fiber optic systems have been proposed lately. In this research work a combination of polarization division multiplexing (PDM) and duty-cycle division multiplexing (DCDM) system is proposed for long haul communication. In the proposed system each PDM channel carries 2-channel DCDM where each user is operating at data rate of 10 Gb/s which forms 2 × 2 × 10 Gb/s optical system. Results show that the bit error rate of 10-9 for worst user is achieved at received power per chip of 21.12 dBm and optical signal to noise ratio of 22.08. Furthermore, system analysis demonstrates that the proposed system can tolerate the ±10 ps/nm dispersion without any need for compensation

Effect of injection strategies on a single-fuel RCCI combustion fueled with isobutanol/isobutanol + DTBP blends

© 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence (http://creativecommons.org/licenses/by-nc-nd/4.0/).In recent years, improved combustion controllability through in-cylinder reactivity stratification by using two different fuels have led to introduction of dual-fuel reactivity controlled compression ignition (RCCI) strategy. In conventional RCCI, gasoline or natural gas can be used as the low-reactivity fuel, and diesel or biodiesel can be used as the high-reactivity fuel. This strategy has the potential to operate with a single low-reactivity fuel and direct injection (DI) of the same fuel blended with a small amount of cetane improver. In the present study, numerical simulations have been carried out to study injection strategy in a single-fuel RCCI engine fueled with isobutanol – isobutanol + 20% di-tert-butyl peroxide (DTBP). Firstly, the effects of start of injection (SOI) timing, injection pressure (pinj), spray cone angle (SCA), and DI fuel ratio were explored. Then, the effect of DI fuel ratio was discussed in each best case in order to decrease the high DI requirement. The results indicate that SOI = −88° ATDC, pinj = 1400 bar, and SCA = 45° can improve the single-fuel RCCI engine performance and emissions compared to the baseline case (SOI = −58° ATDC, pinj = 600 bar, SCA = 72.5°). Moreover, it is shown that by advancing the SOI timing to −88° ATDC, a 20% reduction in DI ratio, 3.3% increase in gross indicated efficiency (GIE) together with reductions in CO, and NOx emissions by 3.56 g/kW-h and 0.254 g/kW-h, could be achieved, respectively.Peer reviewedFinal Accepted Versio

Variable weight spectral amplitude coding for multiservice OCDMA networks

The emergence of heterogeneous applications such as internet data, video streaming, and online gaming, brings in a demand for a network environ- ments with capability of supporting diverse Quality of Services (QoS). Prioritizing the services is essential to ensure the delivery of information is at their best. This paper proposes a new code family to support optical domain service differentiation using spectral amplitude coding techniques within an optical code division multiple access (OCDMA) scenario. A particular user or service has a varying weight applied in order to obtain the desired signal quality. The proposed variable-weight code (VW-code) is constructed based on basic multi-service (MS) code. Mathematical model is developed to for performance evaluation of VW-MS code. In addition, the properties of pro- posed code is compared with other VW-OCDMA codes. It is shown that the proposed VW-MS provide an optimal code length with minimum cross- correlation compared to other VW-codes. Performance of VW-MS designed for triple-play services operating at bit rates of 0.622, 1.25 and 2.5 Gbps is demonstrated

Determining factors and consequences of risk perception in annual reports: Structural equation modeling approach

The current research aims to investigate the effect of the causes and consequences of determining the risk perception of annual reports with the approach of structural equations. The research sample includes 130 companies admitted to the Tehran Stock Exchange in the period from 2008 to 2020. Using the structural equation modeling method, the depth of influence of each of the causes on the feeling of risk and its consequences have been extracted. The consequences of risk perception are the cost of capital and information asymmetry and the causes of risk perception are macroeconomic characteristics, financial performance, ownership structure, board characteristics, structural characteristics, and auditing. In short, based on the obtained results, risk perception has a positive and significant effect on the cost of capital and a positive and significant effect on information asymmetry. In addition, the results of the model test showed that the variables of ownership structure, macroeconomic characteristics, and characteristics of the board of directors have a positive and significant effect on risk perception. Also, the variable of company structural characteristics and ownership structure do not have a significant effect on information asymmetry; And the variables of the company's structural characteristics, the characteristics of the board of directors, and the ownership structure have a positive and significant effect on financial performance.IntroductionThe annual report issued by a company is an important source of information for its stakeholders, such as investors, to obtain an accurate picture of the company's business, risks, and operational and financial results. In addition to the quantitative financial data contained in these reports, one of the most important sections on the form is the disclosure of risk factors about the company, as stakeholders are particularly sensitive to risks. This risk disclosure is considered so important that since 2005 the US Securities and Exchange Commission has required all companies to include a separate section on their forms to discuss the most significant factors that expose the company to risk. This section is now one of the most controversial sections of company annual reports (Campbell et al, 2014). The sense of risk is one of the most important pieces of information disclosed in the capital market and is useful for investors in making decisions and estimating risk and return; So, there is a demand for that disclosure. In fact, the importance of risk perception is due to the impact that different risks have on investors' decisions (Ntim et al, 2014). Based on this, the aim of the current research is to answer the question, what are the factors and consequences that determine the sense of risk in annual reports? Methods & Material:The research method in this study is practical in terms of purpose and "causal and post-event" in terms of design. The relationships between the variables are formulated in the form of a causal model like the model of structural equations in a coherent framework. A two-step path has been taken to test the research hypotheses. In this way, first, the validity of the measures of the latent variable and the optimal fit of the measurement model have been ensured, and then the structural model has been investigated. The current research is for the period 1387-1399 in terms of time and in terms of location, the companies admitted to the Tehran Stock Exchange. The statistical sample of the research was selected using the systematic elimination sampling method and the companies that did not have the desired characteristics were excluded from the statistical sample. Finally, by applying restrictions, 130 companies were selected as the research sample. After classifying the information of the sample companies in Excel software, Max Kyuda software was used to count the frequency of risk feeling words in each report, and then PLS software was used for statistical analysis. Finding:Once the measurement model of the research variables was confirmed using confirmatory factor analysis, path analysis was utilized to test the research hypotheses. The summary of the results of evaluating the structural model in this study is illustrated in the following table: Table 1: A summary of the evaluation results of the structural model of the research  Direct pathPath coefficientT Statistics (|O/STDEV|)P ValuesHypothesis testing resultsRisk Sentiment → Information Asymmetry0/5677/1370/000Not rejectedRisk Sentiment → the cost of capital0.2993.5660/000Not rejectedAudit → Risk Sentiment0/1061/3600.174rejectedAudit → financial performance-0/0590/8460.398rejectedOwnership Structure→ Risk Sentiment0/2372/4130/016Not rejectedOwnership Structure→ Information Asymmetry0/0861/1790/239rejectedOwnership Structure→ financial performance0/5047/1010/000Not rejectedfinancial performance → Risk Sentiment-0/0110/1340/894rejectedfinancial performance → the cost of capital0/2302/5240/012Not rejectedMacroeconomic → Risk Sentiment0/2122/2260/026Not rejectedMacroeconomic → the cost of capital0/1221/2870/199rejectedStructural characteristics of the company→ Risk Sentiment0/0871/0750/283rejectedStructural characteristics of the company→ Information Asymmetry0/0660/9280/354rejectedStructural characteristics of the company→ financial performance0/2053/4510/001Not rejectedBoard Characteristics→ Risk Sentiment0/1762/1440/033Not rejectedBoard Characteristics→ financial performance0/1922/7580/006Not rejected Source: Research findings Results & ConclusionThe results showed that the sense of risk has a positive and significant effect on the cost of capital and information asymmetry, so the seventh and eighth hypotheses were confirmed. The results of previous research were different in this case, for example, the results of Al-Shammari (2014) and Netim et al. (2013) were similar to the results of this research, but Campbell et al. (2014) showed the effect of risk perception on information asymmetry to be insignificant. The effect of audit variables, financial performance, and structural characteristics on the sense of risk has shown to be non-significant, that is, factors such as audit opinion or quality, profitability, liquidity, company size, conservatism, financial leverage per unit of change of these variables have no effect on the company's sense of risk. and does not change, so the first, second, and third hypotheses of the research are rejected. This conclusion was similar to the research result of Ghazali (2008), although Al-Shammari (2014) showed that the larger the size of the company, the greater the sense of risk. Also, the results of the research show that the characteristics of the board of directors have a positive and significant effect on the sense of risk and that factors such as the independence of the board of directors, the size of the board of directors, and the stability of the CEO and the number of board meetings increase the sense of risk in companies. The results of Khoshkhal and Vakili Fard (1400) also reported the effect of the size of the board of directors and the stability of the CEO and the number of meetings of the board of directors on risk, which is in accordance with the present research. Based on the results of the data analysis, the ownership structure and macroeconomic factors have a positive and significant effect on the sense of risk, which has confirmed the fourth and fifth hypotheses of the research, and these results are in line with the findings of Zarik and Lohichi (2017) and Khoshkhlokh and Talibnia (1400)

Development of Multi-Service (MS) for SAC-OCDMA systems

A Multi-Service Optical Code Division Multiple Access (MS-OCDMA) code based on Spectral Amplitude Coding (SAC) is proposed in this paper. The advantage of proposed code on setting a variable number of users in a basic code matrix with a fixed code weight makes it more flexible in generating codewords. The appropriate quality of service required for various network applications can be provided by choosing a different number of users for the basic code matrix of MS code. The properties of the proposed code is compared with other OCDMA codes in terms of code length and maximum cross-correlation. The performance of the MS code mathematically analysed and probability of error for users is plotted as a function of the number of active users and optical received power. Shot, phase induced intensity and thermal noises are considered in mathematical analysis. Results show that by choosing code weight of 4 and optimizing number of users per sequence, the MS code supports up to 82 users, each operating at a bit-rate of 622 Mbps with reference to the Bit Error Rate (BER) of 10−9

Mathematical optimization of variable valve timing for reducing fuel consumption of A SI engine

In this study, the sensitivity analysis and Quasi-Newton algorithms are used to optimize valve timing XU7/L3 engine in order to reduce fuel consumption and increase engine performance. At first, all components of engine are modeled in GT-POWER and a comparison with experimental results is performed to confirm the accuracy of the model. Then, GT-POWER model is coupled with MATLAB-SIMULINK to control inputs and outputs with sensitivity analysis and Quasi-Newton algorithms. The results obtained indicate that optimal valve timing significantly reduces brake specific fuel consumption (BSFC). Moreover, the convergence rate of Quasi-Newton algorithm for reaching the optimal point is higher than the one of sensitivity analysis algorithm

Proposal of multi-service (MS) code to differentiate quality of services for OCDMA systems

The emergence of a broad range of network-driven applications (e.g. multimedia, online gaming) rises the demand for network environments with ability to provide multiservice capabilities with diverse Quality of Service (QoS) requirements. In this paper, a new code family of novel spreading sequences, called Multi-Service (MS) code has been constructed in order to support multiple services in OCDMA system. The performance of the proposed code is demonstrated using mathematical analysis. Different numbers of basic users are used to support triple-play services (audio, data and video) with different QoS requirements. Results indicate that the technique can clearly provide a relative QoS differentiation. Lower value of basic users can support larger number of subscribers as well as delivering better performance in terms of acceptable BER of 10-9 at fixed code weight

Performance analysis of hybrid SAC-OCDMA/WDMA system using Random Diagonal code

A hybrid Spectral-Amplitude-Coding (SAC) - Optical Code Division Multiple Access (OCDMA) /Wavelength - Division-Multiple-Access (WDMA) using Random Diagonal (RD) code is proposed in this paper. The RD code is used in the proposed system due to its receiver's flexibility. The system is simulated using OptiSystem software. In our proposed system, four users of WDMA system with bit rate of 10Gbps is coupled with users of OCDMA system performing on bit rate of 1.25Gbps. Comparing to hybrid SAC-OCDMA /WDMA using KS code, the proposed system offers better performance in term of lower code length and lower bit error rate (BER) at the expense of higher number of filters. The result also shows that the BER of nine RD users are maintained at not more than 10-9 up to 75 km