Preferred Language
Articles
/
joe-676
Variable Structure Control Design for a Magnetic Levitation System
...Show More Authors

In this paper the variable structure control theory is utilized to derive a discontinuous controller to the magnetic levitation system. The magnetic levitation system model is considered uncertain, which subjected to the uncertainty in system parameters, also it is open-loop unstable and strongly nonlinear. The proposed variable structure control to magnetic levitation system is proved, and the area of attraction is determined. Additionally, the chattering, which induced due to the discontinuity in control law, is attenuated by using a non-smooth approximate. With this approximation the resulted controller is a continuous variable structure controller with a determined steady state error according to the selected control parameters. Finally the ability and the effectiveness of the proposed continuous variable structure controller to the magnetic levitation system are verified via numerical simulations. When state initiated inside the area of attraction, the results show that the ball position can be directed to follow various desired positions, with steady state error not exceeding .  

 

Crossref
View Publication Preview PDF
Quick Preview PDF
Publication Date
Thu Jan 12 2023
Journal Name
Mathematics
Dynamical Behavior of a Cancer Growth Model with Chemotherapy and Boosting of the Immune System
...Show More Authors

In this study, we set up and analyze a cancer growth model that integrates a chemotherapy drug with the impact of vitamins in boosting and strengthening the immune system. The aim of this study is to determine the minimal amount of treatment required to eliminate cancer, which will help to reduce harm to patients. It is assumed that vitamins come from organic foods and beverages. The chemotherapy drug is added to delay and eliminate tumor cell growth and division. To that end, we suggest the tumor-immune model, composed of the interaction of tumor and immune cells, which is composed of two ordinary differential equations. The model’s fundamental mathematical properties, such as positivity, boundedness, and equilibrium existence, are exami

... Show More
View Publication Preview PDF
Scopus (20)
Crossref (14)
Scopus Clarivate Crossref
Publication Date
Tue Mar 01 2022
Journal Name
Journal Of Engineering
A Impact of High Voltage Direct Current Link on Transmission Line in Kurdistan Power System
...Show More Authors

Kurdistan power system is expanded along years ago. The electrical power is transmitted through long transmission lines. The main problem of transmission lines is active and reactive power losses. It is important to solve this issue, unless, the most of electrical energy will lost over transmission system. In this study, High Voltage Direct Current links/bipolar connection were connected in a power system to reduce the power losses. The 132kV, 50 Hz, 36 buses Kurdistan power system is used as a study case. The load flow analysis was implemented by using ETAP.16 program in which Newton-Raphson method for three cases. The results show that the losses are reduced after inserted HVDC links.

View Publication Preview PDF
Crossref (1)
Crossref
Publication Date
Mon Oct 12 2020
Journal Name
Molecules
Phase Change Process in a Zigzag Plate Latent Heat Storage System during Melting and Solidification
...Show More Authors

Applying a well-performing heat exchanger is an efficient way to fortify the relatively low thermal response of phase-change materials (PCMs), which have broad application prospects in the fields of thermal management and energy storage. In this study, an improved PCM melting and solidification in corrugated (zigzag) plate heat exchanger are numerically examined compared with smooth (flat) plate heat exchanger in both horizontal and vertical positions. The effects of the channel width (0.5 W, W, and 2 W) and the airflow temperature (318 K, 323 K, and 328 K) are exclusively studied and reported. The results reveal the much better performance of the horizontal corrugated configuration compared with the smooth channel during both melti

... Show More
View Publication
Scopus (48)
Crossref (47)
Scopus Clarivate Crossref
Publication Date
Wed Jan 01 2020
Journal Name
Energy Conversion And Management
Improved PCM melting in a thermal energy storage system of double-pipe helical-coil tube
...Show More Authors

View Publication
Scopus (163)
Crossref (159)
Scopus Clarivate Crossref
Publication Date
Sat Oct 16 2021
Journal Name
Energies
Performance Analysis of a Solar Cooling System with Equal and Unequal Adsorption/Desorption Operating Time
...Show More Authors

In solar-thermal adsorption/desorption processes, it is not always possible to preserve equal operating times for the adsorption/desorption modes due to the fluctuating supply nature of the source which largely affects the system’s operating conditions. This paper seeks to examine the impact of adopting unequal adsorption/desorption times on the entire cooling performance of solar adsorption systems. A cooling system with silica gel–water as adsorbent-adsorbate pair has been built and tested under the climatic condition of Iraq. A mathematical model has been established to predict the system performance, and the results are successfully validated via the experimental findings. The results show that, the system can be operational

... Show More
View Publication
Scopus (12)
Crossref (13)
Scopus Clarivate Crossref
Publication Date
Sat Jan 01 2022
Journal Name
International Journal Of Low-carbon Technologies
Performance evaluation of the photovoltaic thermal system with a fin array and surface zigzag layout
...Show More Authors
Abstract<p>Solar photovoltaic (PV) has many environmental benefits and it is considered to be a practical alternative to traditional energy generation. The electrical conversion efficiency of such systems is inherently limited due to the relatively high thermal resistance of the PV components. An approach for intensifying electrical and thermal production of air-type photovoltaic thermal (PVT) systems via applying a combination of fins and surface zigzags was proposed in this paper. This research study aims to apply three performance enhancers: case B, including internal fins; case C, back surface zigzags; and case D, combinations of fins and surface zigzags; whereas the baseline smooth duct rep</p> ... Show More
View Publication
Scopus (17)
Crossref (16)
Scopus Clarivate Crossref
Publication Date
Wed Jun 01 2022
Journal Name
Political Sciences Journal
US-Russian Interventions in the Caspian-Caucasus Basin Countries after 2001: (Strategies to Re-Impose Control and Influence as a Model)
...Show More Authors

Today, the five Caspian riparian states on the shores of the Caspian Sea (Kazakhstan, Turkmenistan, Azerbaijan, Russia, and Iran) have become a front for ambitions and international and regional competition, especially in light of the features and characteristics that natural geography has endowed them with and their enjoyment of a group of economic and mineral wealth that are not optimally exploited so far which made it a strategic attraction area for international trends and interventions, especially Western ones. It is a battleground for major international companies aiming to monopolize promising industrial investments in order to impose control and influence on the region’s resources and economic wealth and thus impose their forei

... Show More
View Publication Preview PDF
Crossref
Publication Date
Fri Dec 31 2021
Journal Name
Dental And Medical Problems
Effect of the local application of bupivacaine in early pain control following impacted mandibular third molar surgery: A randomized controlled study
...Show More Authors

Background: Postoperative pain is one of the main complications following impacted mandibular third molar (IMTM) surgery. Objectives: The aim of this study was to assess the effect of the local application of bupivacaine on reducing early postoperative pain following IMTM surgery. Material and methods: A prospective, single-blinded, randomized controlled study was conducted on 40 patients who had undergone the surgical removal of an IMTM under local anesthesia. In the study group (n = 20), absorbable gelatin sponge (AGS) soaked in 3 mL of 0.5% plain bupivacaine hydrochloride was locally applied in the post-extraction socket. In the control group (n = 20), AGS soaked in 3 mL of normal saline was used. Pain intensity was assessed using a pa

... Show More
View Publication
Scopus (12)
Crossref (10)
Scopus Clarivate Crossref
Publication Date
Wed Jan 29 2020
Journal Name
Advances In Rheumatology
Neutrophil/lymphocyte and platelet/lymphocyte ratios as potential markers of disease activity in patients with Ankylosing spondylitis: a case-control study
...Show More Authors
Abstract<sec> <title>Background

The neutrophil/ lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) have the potential to be inflammatory markers that reflect the activity of many inflammatory diseases. The aim of this study was to evaluate the NLR and PLR as potential markers of disease activity in patients with ankylosing spondylitis.

Methods

The study involved 132 patients with ankylosing spondylitis and 81 healthy controls matched in terms of age and gender. Their sociodemographic data, disease activity scores using the Bath Ankylosing

... Show More
View Publication
Scopus (46)
Crossref (39)
Scopus Clarivate Crossref
Publication Date
Wed Feb 04 2004
Journal Name
5th Scientific Conference Of Engineering College In University Of Baghdad, 25th -27th Of February, Baghdad, Iraq
Technology and lighting in interior Design.
...Show More Authors