Productivity Estimation of Bulldozers using Generalized Linear Mixed Models

A. Rashidi,H. Rashidi Nejad,Marcel Maghiar 대한토목학회 2014 KSCE JOURNAL OF CIVIL ENGINEERING Vol.18 No.6

The productivity estimation of construction machinery is a significant challenge faced by many earthmoving contractors. Traditionally, contractors have used manufacturers’ catalogues or have simply relied on the site personnel’s experiences to estimatethe equipment production rates. However, various studies have demonstrated that typically, there are large differences between theestimated and real values. In the construction research domain, linear regression and neural network methods have been consideredas popular tools for estimating the productivity of equipment. However, linear regression cannot provide very accurate results, whileneural network methods require an immense volume of historical data for training and testing. Hence, a model that works with asmall dataset and provides results that are accurate enough is required. This paper proposes a generalized linear mixed model as apowerful tool to estimate the productivity of Komatsu D-155A1 bulldozers that are commonly used in many earthmoving job sites indifferent countries. The data for the numerical analysis are collected from actual productivity measurements of 65 bulldozers. Theoutputs of the proposed model are compared with the results obtained by using a standard linear regression model. In this manner, thecapabilities of the proposed method for accurate estimations of productivity rates are demonstrated.

A Review of Pharmacological Treatments for Vaginal Atrophy in Postmenopausal Women in Iran

Farzaneh Rashidi Fakari,Masoumeh Simbar,Maryam Beheshti Nasab,Masoumeh Ghazanfarpour,Fahimeh Rashidi Fakari 대한폐경학회 2020 대한폐경학회지 Vol.26 No.2

Vaginal atrophy is one of the most common menopausal complications and is often overlooked. There are various pharmacological and non-pharmacological treatment approaches to reduce vaginal atrophy; however, no comprehensive study on a convenient, affordable, inexpensive, and noninvasive treatment with fewer complications has been conducted so far. Thus, the current study aimed to provide a systematic review of pharmacological treatment for vaginal atrophy in postmenopausal women in Iran. In this systematic review, all Iranian articles published in Persian or English during 2009 to 2019 were collected and analyzed by searching the Scopus, PubMed, Web of Science, Magiran, Iranian Registry of Clinical Trials (IRCT), and Cochrane Library databases. The inclusion criteria were clinical trials for vaginal atrophy and menopause. Based on the selection criteria, articles with a Jadad scale score of 3 and above were included in the study and qualitatively analyzed. Overall, 15 clinical trials met the inclusion criteria. In total, 12 articles examined the efficacy of pharmacological treatments (including three herbal medicines, three vitamins and dietary supplements, and two chemical drugs) in treating vaginal atrophy in postmenopausal women. Various types of medication have been used to improve vaginal atrophy, and effective treatments include licorice, chamomile, royal jelly, vitamin E, vitamin D, hyaluronic acid, and Vagifem; however, the results of studies on fennel have been inconsistent. However, considering the small number of studies reviewed, further studies with a stronger methodology are needed to confirm the efficacy of these medications.

Genetic and Phenotypic Parameter Estimates of Body Weight at Different Ages and Yearling Fleece Weight in Markhoz Goats

Rashidi, A.,Sheikahmadi, M.,Rostamzadeh, J.,Shrestha, J.N.B. Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.10

The objective of the present study was to estimate genetic parameters for economic traits in Markhoz goats. Data collected from 1993 to 2006 by the Markhoz goat Performance Testing Station in Sanandaj, Iran, were analyzed. The traits recorded as body weight performance at birth (BW), weaning (WW), six month (6MW), nine month (9MW), yearling (YW) and yearling fleece weight (YFW) were investigated. Least square analyses were used for estimation of environmental effects. Genetic parameters were estimated with single and multi trait analysis using restricted maximum likelihood (REML) procedures, under animal models. By ignoring or including maternal additive genetic effects and maternal permanent environmental effects, five different models were fitted for each trait. The effects of sex, type of birth, age of dam and year of birth on the all body weights were significant (p<0.01), but had no effects on YFW except year of birth. Age of kids had significant influences on WW and 6MW (p<0.01). A log likelihood ratio test was carried out for choosing the most suitable model for each trait. Total heritability estimates for YFW and growth traits varied from 0.16 for YFW and WW to 0.41 for YW. For all traits, maternal heritability was lower than direct heritability, ranging from 0.06 for BW to 0.01 for 6MW and 9MW. The magnitude of $c^2$ was more substantial for BW than the others, and relative importance was reduced from 0.12 for BW to 0.04 for 9MW. The direct additive genetic correlations estimates were positive and varied from 0.21 between BW-YW to 0.96 between WW-6MW. Direct additive genetic correlations between YFW and body weight traits were positive and ranged from 0.14 between BW-YFW to 0.67 between 6MW-YFW. For all traits, the corresponding estimates for phenotypic correlation were positive and lower than genetic correlations. The maternal additive genetic correlations between various traits were varied and ranged from -0.19 between 9MW-YFW to 0.96 between 6MW-9MW. The estimates of the maternal permanent environmental correlations between various traits were positive and ranged from 0.33 between WW-YFW to 0.93 between WW-6MW. Also, the environmental correlations between various traits ranged from 0.01 between BW-YFW and WW-YFW to 0.70 between 9MW-YW. Estimates of genetic parameters for various traits in this study confirm that selection should be applied on WW for genetic improvement in Markhoz goats.

Acoustic Noise Reduction and Power Factor Correction in Switched Reluctance Motor Drives

Rashidi, Amir,Saghaiannejad, Sayed Mortaza,Mousavi, Sayed Javad The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.1

In this paper, a four-phase 8/6-pole 4-kW SR motor drive model is presented. Based on experimental data, the model allows an accurate simulation of a drive in dynamic operation. Simulations are performed and a laboratory type set-up is built based on a TI TMS320F2812 platform to experimentally verify the theoretical results obtained for a SR motor. To reduce acoustic noise and to correct the power factor of this drive, a two-stage power converter is proposed that uses a current source rectifier (CSR) as the input stage for the asymmetrical converter of the studied SRM. Employing the space-vector modulation (SVM) method in matrix converters, the CSR switching allows the dc link's capacitors to be eliminated and the power factor of the SRM drive to be improved. As the electrical motive force (emf) is directly proportional to the rotor speed, the input voltage to the machine can be programmed to be a function of the speed with the modulation index of the CSR, leading to a reduction in the acoustic noise of the SRM drive. Simulation of the whole SRM drive system is performed using MATLAB-Simulink. The results fully comply with the required conditions such as power factor correction with an improvement in the THD.

A novel Kalina power-cooling cycle with an ejector absorption refrigeration cycle: Thermodynamic modelling and pinch analysis

Rashidi, Jouan,Yoo, ChangKyoo Elsevier 2018 Energy conversion and management Vol.162 No.-

<P><B>Abstract</B></P> <P>A new power and cooling cogeneration cycle is proposed that combines the Kalina power cycle and the ejector absorption refrigeration cycle with an ammonia-water mixture as the working fluid. The proposed system, Kalina power-cooling with an ejector cycle (KPCE), originates from the Kalina power and cooling cycle (KPCC) and introduces an ejector before the evaporator. Thermodynamic analyses from the viewpoints of energy efficiency, as well as comparisons between KPCC and KPCE under the same initial conditions, were conducted for the cycles’ refrigeration output and thermal efficiency. Energy analysis results showed that the KPCE provides a performance improvement without greatly increasing system complexity. At the same power production level, the refrigeration output and thermal efficiency of KPCE is 13.5% higher and 17% more than KPCC, respectively. Energy losses due to inefficient heat recovery design of the system are identified by cross heat pinch analysis. All three preheaters of the system showed an inefficient design of heat recovery. After redesigning, power, and power-cooling efficiencies showed 7% and 4.3% increases, respectively. The effect of four important input parameters including three pressure levels and ammonia mass fraction on the KPCE performance are investigated to optimize the system. The optimized KPCE performance improved by 17.9% and 13.6% for power and power-cooling efficiency while the total annual cost of the system could decrease by 6.8%.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Proposed a novel power-cooling cogeneration system based on ejector absorption and Kalina cycles. </LI> <LI> Model-based comparisons according to energy, economic, thermodynamic analyses. </LI> <LI> Optima heat recovery design with heat pinch analysis. </LI> <LI> The optimized KPCE improved power and power-cooling efficiency by 17.9% and 13.6%. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Exergy, exergo-economic, and exergy-pinch analyses (EXPA) of the kalina power-cooling cycle with an ejector

Rashidi, Jouan,Yoo, ChangKyoo Elsevier 2018 ENERGY Vol.155 No.-

<P><B>Abstract</B></P> <P>This paper intends to optimize a new power and cooling cogeneration system, Kalina power-cooling with an ejector cycle (KPCE). The cycle combines the Kalina power cycle and the ejector absorption refrigeration cycle, with an ammonia-water mixture as the working fluid. To this aim, given the thermodynamic model, the potential improvements to the KPCE components are identified by performing exergy and exergo-economic analyses. Then, the system is optimized through a combination of exergy and pinch analyses (EXPA) to find out the direction of improvement and modifications of the system. This system operates with a thermal efficiency of 12.9% and power-cooling efficiency of 25%, providing 459 kW of power and 439.5 kW of cooling. KPCE showed a total exergy efficiency and exergy destruction of 69.8% and 1076 kW, respectively. Components with the highest exergy destruction and lowest exergy efficiency and unit cost rate are identified. According to EXPA, the system achieved a 5% lower overall cost rate and higher cooling generation, which resulted in higher thermodynamic efficiencies. The modified KPCE showed increases of 32%, 36%, and 32% in thermal, power-cooling, and exergy efficiencies, respectively. Compared with other Kalina power-cooling cycles, the optimized KPCE is introduced as a high-performance power-cooling cogeneration system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Exergy based optimization of new Kalina power-cooling cycle with ejector. </LI> <LI> Model-based comparisons according to thermodynamic performance. </LI> <LI> Optimized heat recovery and refrigerator shaft work via exergy-pinch analysis. </LI> <LI> Improved Kalina power-cooling cycle achieving power-cooling efficiency of 29%. </LI> <LI> Exergy efficiency improvement from 64% to 85%. </LI> </UL> </P>

Potentials of porous materials for energy management in heat exchangers – A comprehensive review

Rashidi, Saman,Kashefi, Mohammad Hossein,Kim, Kyung Chun,Samimi-Abianeh, Omid ELSEVIER 2019 APPLIED ENERGY -BARKING THEN OXFORD- Vol.243 No.-

<P><B>Abstract</B></P> <P>Heat exchangers are recognized as popular thermal devices with various and important applications in industrial energy systems. Many techniques were employed in order to manage the energy in these devices. Among these techniques, porous materials with high potentials for the energy management and enhancing the thermal performances in heat exchangers were employed widely. This paper reviews recent developments and utilisation of different types of porous materials in the heat exchangers. Both simulation and experimental works were briefly explained. The gaps in current literatures and designs were investigated and solutions for them were discussed.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Potentials of porous materials in the heat exchangers are reviewed in this paper. </LI> <LI> Both simulation and experimental works are briefly explained. </LI> <LI> Gaps in current literatures are investigated and solutions for them are discussed. </LI> <LI> Porous media with larger porosity and conductivity are proper for heat exchangers. </LI> <LI> Fouling in porous materials can provide some negative effects in heat exchangers. </LI> </UL> </P>

Multiple criteria decision making method for selecting of sealing element for earth dams considering long and short terms goals

Rashidi, Babak,Shirangi, Ehsan,Baymaninezhad, Matin Techno-Press 2018 Wind and Structures, An International Journal (WAS Vol.26 No.2

Nowadays, using math logic in great civil projects is considered by the clients to achieve the goals of project including quality optimization, costs, avoiding individual, emotional and political decision making, long-term and short-term goals and they are the main requirements of each project and should be considered by the decision makers to avoid the illogical decision making applied on the majority of civil projects and this imposes great financial and spiritual costs on our country. The present study attempts to present one of the civil projects (Ghasre Shirin storage dam) whose client was not ministry of energy for the first time and the short-term and long-term goals of the private sector were applied based on the triangle of quality, cost and time. Also, the math logic and model (multi-criteria decision making method and decision making matrix) is used in one of the most important sections of project, sealing element, policies and new materials (Geosynthetics) are considered and this leads to suitable decision making in this regard. It is worth to mention that this method is used for other sections of a dam including body, water diversion system, diaphragm and other sectors or in other civil projects of building, road construction, etc.

A Decision Support Methodology for Remediation Planning of Concrete Bridges

Rashidi, Maria,Lemass, Brett Korea Institute of Construction Engineering and Ma 2011 Journal of construction engineering and project ma Vol.1 No.2

Bridges are critical and valuable components in any road and rail transportation network. Therefore bridge remediation has always been a top priority for asset managers and engineers, but identifying the nature of true defect deterioration and associated remediation treatments remains a complex task. Nowadays Decision Support Systems (DSS) are widely used to assist decision makers across an extensive spectrum of unstructured decision environments. The main objective of this research is to develop a requirements-driven methodology for bridge monitoring and maintenance which has the ability to assess the bridge condition and find the best remediation treatments using Simple Multi Attribute Rating Technique (SMART); with the aim of maintaining a bridge within acceptable limits of safety, serviceability and sustainability.

Carbon dioxide absorption by Ammonia-promoted aqueous triethanolamine solution in a packed bed

Rashidi Hamed,Azimi Hossein,Rasouli Parvaneh 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

CO2 absorption by ammonia added triethanolamine aqueous solution as a promoter was investigated in terms of absorption percentage (AP), overall volumetric mass transfer coefficient (KGae), and molar flux (NA) in a packed column. Three variables of ammonia concentration (0–5 wt%), Triethanolamine concentration (10–30 wt%), and gas flow rate (1,500–2,500 ml/min) were considered as significant variables in absorption performance. Effect of these variables and their interactions were inspected using the three level factorial response-surface method. Statistical analysis of the results showed that an ammonia concentration with 72.99%, 71.83, and 81.12% has the greatest effect on AP%, NA, and KGae, respectively. Then, gas flow rate with 5.27% and 3.90%, had a great effect on AP% and KGae, respectively. Finally, the optimal operating conditions were determined to maximize the responses. Under optimal operating conditions, the maximum values for AP%, KGae, and NA were 98.94%, 0.202 kmol/h·m3·kPa, and 3.901 kmol/m2·h, respectively. Thus, adding ammonia to triethanolamine considerably improves the mass transfer performance of solvent.