Preferred Language
Articles
/
JRdlZ5IBVTCNdQwChK9i
Performance Analysis of Finite-Time Generalized Proportional Integral Observer for Uncertain Brunovsky Systems
...Show More Authors

This paper proposes a novel finite-time generalized proportional integral observer (FTGPIO) based a sliding mode control (SMC) scheme for the tracking control problem of high order uncertain systems subject to fast time-varying disturbances. For this purpose, the construction of the controller consists of two consecutive steps. First, the novel FTGPIO is designed to observe unmeasurable plant dynamics states and disturbance with its higher time derivatives in finite time rather than infinite time as in the standard GPIO. In the FTGPO estimator, the finite time convergence rate of estimations is well achieved, whereas the convergence rate of estimations by classical GPIO is asymptotic and slow. Secondly, on the basis of the finite and fast estimations, the SMC scheme is constructed in order to compensate estimation errors in both states and disturbance. Finally, the tracking efficiency is verified by carrying out many simulations on the application example of flexible joint robot (FJR). Besides, comparing the proposed method with the standard GPIO based SMC method is performed.

Scopus Crossref
View Publication
Publication Date
Thu Jun 05 2014
Journal Name
Arabian Journal Of Geosciences
Applying the cluster analysis technique in logfacies determination for Mishrif Formation, Amara oil field, South Eastern Iraq
...Show More Authors

View Publication
Scopus (11)
Crossref (8)
Scopus Clarivate Crossref
Publication Date
Tue Sep 07 2021
Journal Name
Journal Of Petroleum Exploration And Production Technology
Wellbore instability management using geomechanical modeling and wellbore stability analysis for Zubair shale formation in Southern Iraq
...Show More Authors
Abstract<p>Wellbore instability problems cause nonproductive time, especially during drilling operations in the shale formations. These problems include stuck pipe, caving, lost circulation, and the tight hole, requiring more time to treat and therefore additional costs. The extensive hole collapse problem is considered one of the main challenges experienced when drilling in the Zubair shale formation. In turn, it is caused by nonproductive time and increasing well drilling expenditure. In this study, geomechanical modeling was used to determine a suitable mud weight window to overpass these problems and improve drilling performance for well development. Three failure criteria, including Mohr–Coulomb, modifie</p> ... Show More
View Publication
Scopus (45)
Crossref (42)
Scopus Clarivate Crossref
Publication Date
Thu Dec 01 2016
Journal Name
Journal Of Economics And Administrative Sciences
The relationship between oil revenues and financial sustainability in the Iraq analysis for the period (1990-2013)
...Show More Authors

This study aimed to analyze and measure the relationship between oil revenues and financial sustainability in Iraq, the study used the stylistic approach inductive and deductive approach. Accompanied by the use of quantitative and analytical style, which was based on two variables oil revenues and net general budget on annual data covered the period (1990-2013). Among the most important findings of the study contain the time-series variables study on the root of the unit and is not stable in the general level, and become stable after the use of mathematical processors to gain access to a stable by taking the first difference of natural Ogartm of the series. The way (Johnson) to a long-term relationship between oil revenues and ne

... Show More
View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Thu Dec 31 2020
Journal Name
Journal Of Accounting And Financial Studies ( Jafs )
Financial analysis indicators and their impact on investment decision-making: for the national insurance company (applied research)
...Show More Authors

The financial analysis of the published financial statements is the means that enables businessmen, financial institutions, financial analysts and others to conduct their studies and conclusions to obtain information that helps them in the decision-making process, including decisions related to investment. National in making the decision on the investment activity, for the period from 2012 to 2018, through the information provided by the annual financial statements, by selecting a set of indicators provided by the financial statements, namely (liquidity ratio, activity percentage, profitability ratios) to measure the extent of this ability Indicators in determining their role in making an investment decision.

View Publication Preview PDF
Publication Date
Wed Sep 30 2020
Journal Name
Cfd Letters
Numerical Analysis for Solar Panel Subjected with an External Force to Overcome Adhesive Force in Desert Areas
...Show More Authors

View Publication
Scopus (21)
Crossref (21)
Scopus Crossref
Publication Date
Mon Mar 12 2018
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
The Effect of Crystallization Time and Acid Type on the Synthesis of Nano-Gamma Alumina Using Double Hydrothermal Method
...Show More Authors

Double hydrothermal method was used to prepare nano gamma alumina   using aluminum nitrate nano hydrate and sodium aluminate as an aluminum source, CTAB (cetyltrimethylammonium bromide) as surfactant, and variable acids: weak acids like; citric, and acitic acids, and strong acids like; hydrochloric and nitric acids as a bridge between aluminum salts and surfactant. Different crystallization times  12, 24, 48, and 72 hrs were applied. All the batches were prepared at pH equals to 9. XRD diffraction technique was used to investigate the crystalline nano gamma alumina pure from surfactant. N2 adsorption-desorption (BET) was used to measure the surface area and pore volume of the prepared nano alumina, the average p

... Show More
View Publication Preview PDF
Publication Date
Thu Apr 02 2020
Journal Name
Iop Conference Series: Materials Science And Engineering
The effects of additives in to heat treatment temperature and time on the crystallinity of lithium silicate glass-ceramic
...Show More Authors

View Publication
Scopus (1)
Crossref (1)
Scopus Crossref
Publication Date
Sun Dec 30 2007
Journal Name
Iraqi Journal Of Chemical And Petroleum Engineering
The Effect of Time and Corrosion Products Formation on Corrosion Rate of Carbon Steel Pipe Under Turbulent Flow Conditions
...Show More Authors

The effect of time (or corrosion products formation) on corrosion rates of carbon steel pipe in aerated 0.1N NaCl
solution under turbulent flow conditions is investigated. Tests are conducted using electrochemical polarization
technique by determining the limiting current density of oxygen reduction in Reynolds number range of 15000 to 110000
and temperature range of 30 to 60oC. The effect of corrosion products formation on the friction factor is studied and
discussed. Corrosion process is analyzed as a mass transfer operation and the mass transfer theory is employed to
express the corrosion rate. The results are compared with many proposed models particularly those based on the
concept of analogy among momentum, heat,

... Show More
View Publication Preview PDF
Publication Date
Fri Feb 10 2023
Journal Name
Dentistry Journal
The Role of Social Media in Communication and Learning at the Time of COVID-19 Lockdown—An Online Survey
...Show More Authors

This study aimed to assess orthodontic postgraduate students’ use of social media during the COVID-19 lockdown. Ninety-four postgraduate students (67 master’s students and 27 doctoral students) were enrolled in the study and asked to fill in an online questionnaire by answering questions regarding their use of social media during the COVID-19 lockdown. The frequency distributions and percentages were calculated using SPSS software. The results showed that 99% of the students used social media. The most frequently used type of social media was Facebook, 94%, followed by YouTube, 78%, and Instagram, 65%, while Twitter and Linkedin were used less, and no one used Blogger. About 63% of the students used elements of social media to l

... Show More
View Publication
Scopus (15)
Crossref (13)
Scopus Clarivate Crossref
Publication Date
Wed Nov 03 2021
Journal Name
Journal Of Engineering Research
Performance of quadrilateral perforated prestressed concrete rafters
...Show More Authors

This study focuses on the behavior of simply supported perforated prestressed concrete rafters (PPCRs) under single midspan monotonic static loading. The experimental program consisted of testing seven specimens; one solid (control) rafter, and six perforated with quadrilateral openings. The main investigated variables are the number and height of the openings. The test findings indicate that, in comparison to the solid rafter, the presence of quadrilateral openings in the PPCRs led to reducing the load capacity by (4.3-36%) and increase the midspan deflection at ultimate by (14.8-33%). Also, increasing the number of concrete posts between openings resulted in increasing the failure load and decreasing the deflection at all stages o

... Show More
View Publication
Crossref (1)
Crossref