Performance Analysis of Non Linear Field Oriented Controlled Induction Motor Drive for Improved Performance - Effect of Intermittent Loading
Authors: Ekwuribe James Michael , Okoro Christopher Kalu
In Research
Attempt has been made in previous works to improve the steady state and dynamic performances of the vector controlled induction motor drives. The Input-output (I/O) linearization and decoupling technique which are based on the concepts of differential geometry and vector control has been used in the decoupling of speed or torque from the flux of induction motor drives. This paper investigates the effects of non-linearity on the performance of field oriented control of induction motor drive at intermittent loading, Nonlinear control are better seen implemented in large dynamic systems invoking non linearity. the effects of intermittent loading at no load, full, 10%, 20%, 50% and 80% loading where checked on the speed and electromagnetic torque of the induction motor being controlled, stator current and rotor current were also important parameters affected by non-linearity in control under intermittent loading. The results obtained gave a detailed comparison of the distortions present in motor control when not properly controlled. A comparative study of the system under loading conditions were checked under control for linear and non-linearity. Matlab/Simulink was used to model the induction motor drive and also simulate the dynamic performance of the system as load is being varied. The robustness of Matlab/Simulink was used to enable efficient intermittent loading at various points of the simulation, the data logout tool of Matlab/Simulink were also used for data collection analysis and comparison.
On the Evaluation of the Neural Network Khartoum Geoid Model
Authors: Kamal Abdellatif Sami , Ammar Mohammed Maryod Aborida
In Research
This study was carried out to establish and evaluate an Artificial Neural Networks (ANN) geoid model for the Khartoum State. In the first stage the geometrical geoid heights were obtained from the differences between observed ellipsoidal heights and known orthometric heights of 48 geodetic Ground Control Points (GCP) in the study area. This followed by generating an ANN geoid model to extract the geoid heights from 42 ground control stations in the same study area in the Khartoum State. The main objective of this research study is to apply an ANN to model the Geoid surface using the back propagation algorithm in Khartoum state, through supervised training by geoidal undulations values. The WGS84 GPS/levelling geoid is computed then their results were used for comparison and evaluation of the determined ANN Geoid surface. In this study the geometrical geoid model was determined using the well-known geometrical geoid determination approach taking consideration of the distribution of the existing vertical control points in Khartoum area, with an intention of determining the orthometric heights of any point of unknown heights with uncertainties of less than 5cm. The ANN geoid uncertainties were evaluated and tested at 6 geodetic ground control points. The average difference between the derived geoid heights obtained from the geometrical geoid model, and their corresponding ANN geoid heights was found to be in the range of ±3 cm. Based on the test results of the statistical analysis and the study of a trained artificial neural networks model, the authors were able to estimate the geoid model with acceptable accuracy and can interactively be available for end users. This study showed that, the geoid heights in Khartoum State can be determined with the ANN method with typical accuracy of better than 5cm.
Numerical Analysis of Circular, Square, and Rectangular Composite Columns Under Axial and Torsional Loads
Authors: Marsimoyi Terefe Bango
In Research
This paper presents a numerical analysis of different sections of circular, square, and rectangular composite columns subjected to axial and torsional loads to characterize the composite columns section performance for different purposes of construction. To accomplish the objective of this study, a parametric examination was conducted. Nine different types of composite columns were investigated. A [circular, square, rectangular] composite column with concrete-filled, with reinforcement bars, and with embedded steel profile were investigated in detail under axial load only and combined effect of axial and torsional loads separately. The strength of composite column materials considered uniformly for concrete, Steel profile, Reinforcement bars in quality, and utilized to determine their impacts under ultimate axial load capacity was examined. The composite columns under load impacts of various percentage 40%, 50% and 60% of its ultimate axial load capacity (P) with a constant magnitude were numerically analyzed. In this paper, different types of composite columns are taken for analysis by making bottom end fully fixed and another top end as pinned support, while the concentrated load and torsion are applied at this point for loading analysis. The FEM software called Abaqus was used for modeling and analysis of composite column by method of finite element considering three-dimensional models for all composite columns’ materials. Concentrated load and Torsion will be applied on the top end of the composite column at the reference point constraint at top-end by coupling. The result analysis is demonstrated to determine the impacts of various levels of axial loads on the behaviour of columns subjected to axial and torsional loading on different composite material, and assessing high and low stress and strain zones, loading compression, rotation and twisting structural properties was investigated.
Economic Evaluation of Chemical Inhibitors for Hydrate Solution in Nigeria Oilfield Flowlines
Authors: Precious Joseph Ekpo , Uche Osokogwu , Solomon Williams
In Research
Oil and gas companies across the world have expanded their operations to cold environments like the Offshore Deep-water for more conventional and economical reservoirs as a result of global demand for energy. As Hydrocarbon production continues to increase from both conventional and unconventional reservoirs in harsh environments, Hydrates presents a huge problem in the oil and gas industry because it leads to production losses, and is very expensive in trying to prevent its formation or removal. The hydrate blockage during Deepwater oil and gas exploration will also damage the equipment and threaten personal safety. It also leads to flow interruptions, environmental and safety problems, the interruptions leads to plugging of the flowline, Hydrates still cost the oil and gas industries millions of dollars annually. This paper discusses the existing chemical inhibitors used to mitigate hydrates as well as evaluating economically the cost implication for twelve years in Niger-Delta. In this study, three different types of chemical inhibitors (i.e. Methanol, Mono-ethylene glycol and KHI) were economically evaluated through a cash flow model and eventually the Net Present Value, Internal Rate of Return, Profitability Index, Present Value Ratio and Payback Period were determined and Monte Carlo Simulation was also used to get NPV, IRR and their uncertainties. Their charts show that KHI will generate an NPV of $20.34MM if invested in at Return of Investment of 28% and will also take a period of 3.76 years to recover the investment made into the project. From the analysis, KHI is a better project to invest in because it generates more profit and has a lesser risk than Methanol and Mono-ethylene glycol.
Association of Leptin Receptor Gene Polymorphisms with Blood Glucose Concentration and Obesity
Authors: Mo Mo Than , Yan Naing Soe , Zaw Myo Lwin , Ye Wint Kyaw , Kyaw Thet Paing , Khine Kyaw Oo , Phyo Thaw Htun , Aung Lin Oo , Min Thein , Ye Myat Kyaw , Zaw Min Htut
In Research
Obesity has become a global epidemic and is a known risk factor for several adverse health outcomes. Single Nucleotide Polymorphism (SNP) in leptin receptor genes become interesting candidates as susceptibility genes for obesity and glucose homeostasis. The present study intended to explore the genetic analysis of LEPR gene K109, Q223R, and K656N polymorphisms and their relation to obesity and fasting plasma glucose (FPG) concentration in the Myanmar population. One hundred and fifty diagnosed obese subjects and 150 healthy non-obese controls were included. Fasting plasma glucose (FPG) was measured and LEPR gene K109R, Q223R, and K656N polymorphisms were detected by DNA analysis. Data were analyzed by chi-square and one-way ANOVA tests. Each genotype frequency distribution of LEPR gene (K109R, Q223R, and K656N) polymorphisms was not associated with obesity (p > 0.05), as well as each allele frequency distribution also similar outcome (p > 0.05). FPG levels of the study population showed no significant differences between each genotype of LEPR gene polymorphisms (p > 0.05). The K109R, Q223R, and K656N polymorphisms of the LEPR gene were not linked to obesity or FPG levels in the population of Myanmar, according to our findings. Therefore, it does not seem that these polymorphisms have an equivalently significant role for the people of Myanmar. To completely understand the unique genetic variables that predispose to obesity in humans, an ongoing study of diverse obesity phenotypes and related gene mutations is necessary as our understanding of the genes causing obesity increases as a result of new findings.
The Effect of Coffee Expansion on Carbon Stock of Natural Forest in Gidame Woreda, West Ethiopia
Authors: Yadesa Akena Dinsa
In Research
The important climate-related functions of forest ecosystems are carbon sequestration, regulating the global carbon cycle and climate change mitigation. About 80% of the terrestrial carbon is stored as forest biomass and soil organic carbon. Deforestation and forest degradation show an alarming high, mainly due to the conversion of natural forest to commercial and cereal crop production. By considering this issue, this study was conducted with the aim to assess the effect of coffee expansion on carbon stock of the natural forest ecosystem in Gidame woreda. The study site was stratified in two strata: undisturbed natural forest and disturbed coffee forest. A total of 71 nested square sample plot was determined, proportionally allocated (29 for undisturbed and 42 for disturbed/coffee forest) and randomly distributed within each stratum. In both cases, the diameter at breast height and tree height were measured; litter sample was collected by harvesting and weighing technique. A total of 72 composite soil samples were also collected from proportionally and randomly selected 24 sample plots; 10 from undisturbed natural forest and 14 from disturbed coffee forest for SOC quantification in three layers (0-15cm, 16-30cm, and 31-45cm). From these forest inventory data, the above-ground biomass carbon stock was estimated by using allometric equations. The below-ground biomass carbon stock was derived from the above-ground carbon stock. The results showed that the biomass carbon stock was 298.758 ± 9.4tc/ha for undisturbed natural forest and 199.895 ± 11tc/ha for disturbed coffee forest and the difference is statistically significant as p < 0.05. This revealed that the disturbance of this natural forest ecosystem, which is associated with the conversion of natural forest to the coffee cultivation area, resulted in the loss of 33.09% of the biomass carbon stock. The SOC is 148.40 ± 12tc/ha for undisturbed forest and 153.80 ± 4.30tc/ha for disturbed coffee forest has no significant difference as p > 0.05. Therefore, maintaining the biomass carbon sequestration potential of this natural forest ecosystem should be required through the implementation of different conservation mechanisms.
Biological Parameters of the Red Pandora (Pagellus bellottii Steindachner, 1882) in Soumbedioune, Senegal, West Africa
Authors: Waly Ndiaye , Alassane Sarr , Patrick Diédhiou
In Research
New information on the reproductive biology of Pagellus bellottii (Steindachner, 1882) a Sparid fish in Senegalese waters is provided in this study. Little aspects on the reproductive biology of this fish are reported in Senegal, West Africa. The objective of the study is to examine the length-weight relationship, the condition factor and the reproductive parameters of P. bellottii from the Senegalese waters. A total of 360 specimens (males = 197 and females = 163) bought from fishermen were used for the study. Specimens were collected monthly (thirty individuals per month) from October 2019 to September 2020 from Soumbedioune of Western part of Dakar, Senegal. Each individual was measured with an ichthyometer and weighed with a precision balance. For dissected individuals, sex was determined by macroscopic observation of the gonads. The gonads were extracted to calculate the Gonadosomatic Index. The length-weight relationship gave a negative allometric growth for both sexes. The value of “k” being greater than 1; the species was in good condition in this environment. The sex ratio (1:0.82) was favourable to males. The reproductive period was from March to June with a spawning peak in April for both sexes. Males and females had size at first sexual maturity at 178- and 180-mm total length, respectively. Males matured at smaller sizes than females. The data obtained in this study on some aspects of the reproductive biology of P. bellottii will be essential for better management of fish stocks in Senegal and in the sub-region.
Correlation of Tree Diameter, Height and Biodiversity with Soil N, P and K
Authors: Shreejana Panthi , Ram Asheshwar Mandal , Ajay Bhakta Mathema
In Research
This research was done to assess effect of soil nutrients (N, P and K) on diameter at breast height (DBH), height and biodiversity. Three transect lines according to altitudinal gradient were established to systematically allocate the plot. Total 45 samples having 20m×25m were established to collect the biophysical data and soil samples. DBH and height of trees were recorded and soil samples were carried out in the lab. The Shannon –Weiner Index, Simpson Index and Evenness Index were analyzed. Nitrogen (N), Phosphorous (P) and Potash (K) was analyzed using Kjeldahl, Olsen’s and Somers and Flame photometric methods respectively. The Pearson’s correlation was performed to show the relation of DBH, height and biodiversity indexes with N, P and K. Descriptive statistics showed that the highest Mean±SE DBH (cm) was 50.75±4.61 in altitude
Discussion on Molecular Mechanism of Siwei Xiaoliuyin in Treating Glioma Based on Network Pharmacology and Molecular Docking
Authors: Biaogang Han , Xiaohong Wu , Xiaopei Zhang , Shihua Liu , Yongqing Shen , Aixia Sui
In Research
Background. Siwei Xiaoliuyin, a traditional Chinese medicine, is effective in treating glioma, but its molecular mechanism of action is still unclear. In this paper, we will explore the molecular mechanism of Siwei Xiaoliuyin in the treatment of glioma through network pharmacology. Methods. The potential active components and molecular targets of Siwei Xiaoliuyin were collected through the pharmacological database and analysis platform of traditional Chinese medicine system and TCMID database; glioma-related target genes were obtained through the GenCards database, OMIM database and Disgenet database; the intersection of drug action targets and disease genes was extracted using R software, and Venn diagram was drawn; the key targets were imported into the String database to construct a protein interaction network; the key targets were imported into R software using clusterProfiler for GO and KEGG enrichment analysis; the main components of Siwei Xiaoliuyin were molecularly docked with the Hub gene by AutoDock Vina technology. Results. Siwei Xiaoliuyin consists of four components, which are Curcuma zedoaria, Tianlong, Solanum nigrum and Smilax glabra and a total of 26 potential active components and 56 targets were identified from it, 5750 glioma-related genes and 47 key target genes crossed between Siwei Xiaoliuyin and glioma. The results of enrichment analysis showed that GO entries involved fatty acid metabolic processes, response to steroid hormones and other processes. KEGG analysis identified key genes mainly enriched in PI3K-Akt signaling pathway, estrogen signaling pathway and HIF-1 signaling pathway, etc. The results of molecular docking showed that Diosgenin, the main component of Siwei Xiaoliuyin, docked well with the AHR gene. Conclusions. Through network pharmacology prediction, Siwei Xiaoliuyin may regulate multiple signaling pathways such as PI3K-Akt, estrogen and HIF-1 through multiple targets EGFR, ESR1, VEGFA, AHR and AR, thus affecting the function of multiple cells and playing an important role in the treatment of glioma.