Currently, one of the topical areas of application of machine learning methods is the prediction of material characteristics. The aim of this work is to develop machine learning models for determining the rheological properties of polymers from experimental stress relaxation curves. The paper presents an overview of the main directions of metaheuristic approaches (local search, evolutionary algorithms) to solving combinatorial optimization problems. Metaheuristic algorithms for solving some important combinatorial optimization problems are described, with special emphasis on the construction of decision trees. A comparative analysis of algorithms for solving the regression problem in CatBoost Regressor has been carried out. The object of the study is the generated data sets obtained on the basis of theoretical stress relaxation curves. Tables of initial data for training models for all samples are presented, a statistical analysis of the characteristics of the initial data sets is carried out. The total number of numerical experiments for all samples was 346020 variations. When developing the models, CatBoost artificial intelligence methods were used, regularization methods (Weight Decay, Decoupled Weight Decay Regularization, Augmentation) were used to improve the accuracy of the model, and the Z-Score method was used to normalize the data. As a result of the study, intelligent models were developed to determine the rheological parameters of polymers included in the generalized non-linear Maxwell-Gurevich equation (initial relaxation viscosity, velocity modulus) using generated data sets for the EDT-10 epoxy binder as an example. Based on the results of testing the models, the quality of the models was assessed, graphs of forecasts for trainees and test samples, graphs of forecast errors were plotted. Intelligent models are based on the CatBoost algorithm and implemented in the Jupyter Notebook environment in Python. The constructed models have passed the quality assessment according to the following metrics: MAE, MSE, RMSE, MAPE. The maximum value of model error predictions was 0.86 for the MAPE metric, and the minimum value of model error predictions was 0.001 for the MSE metric. Model performance estimates obtained during testing are valid.
Vacuum gas oil (611-833)K was distilled from Kirkuk crude oil, which was obtained by blending the following fraction,
light vacuum gas oil (611 - 650) K, medium vacuum gas oil (650-690)K, heavy vacuum gas oil (690-727)K and very
heavy vacuum gas oil (727-833)K.
The vacuum gas oil was hydrotreated on a commercial cobalt-molybdenum alumina catalyst presulfied at specified
condition in a laboratory trickle bed reactor. The reaction temperature varied from (583-643)K over liquid hourly space
velocity ranging between (1.5-3.75)h-1 , Hydrogen pressure was kept constant at 3.5 MPa with a hydrogen to oil ratio
of about 250 L/L
The conversion results for desulfurization appeared to obey the second order kinetics. According to
The present work is concerned with the finding of the optimum conditions for biochemical wastewater treatment for a local tannery. The water samples were taken from outline areas (the wastewater of the chrome and vegetable tannery) in equal volumes and subjected to sedimentation, biological treatment, and chemical and natural sedimentation treatment.
The Box-Wilson method of experimental design was adopted to find useful relationships between three operating variables that affect the treatment processes (temperature, aeration period and phosphate concentration) on the Biochemical Oxygen Demand (BOD5).
The experimental data collected by this method were successfully fitted to a second order polynomial mathematical model. The most fa
In the present work, a program for calculating the coefficients of the Aplanatic Cassegrain Telescope (ACT) system, free from the effects of spherical and coma aberrations, were constructed. In addition, the two-mirrors of the optical system, as aspherical surfaces, were adopted. This means, that the two-equations of the mirrors are assumed to be polynomial function of five even terms only. The numerical method, least-squares curve fitting method to calculate the two-mirror coefficients system, was adopted. For choosing the values and ratios that give the best results, Rayleigh Criterion (Rayleigh Limit), for purpose of comparison and preference, was adopted.
Objective(s): To assess the types of violence among adolescents in Baghdad City.
A descripƟve study which was using the assessment approach was conducted on purposive sample of 60 parents of
adolescent for identify types of adolescents violence in their families, was selected according to specific criteria for
participating in health education program towards adolescents' violence control in Baghdad city.
Methodology: A questionnaire was constructed for the purpose of the study. It was consisted of two parts; the first
part which included the parents' demographic characteristics for parents (sex, age, educational level and socioeconomic
status); the second part included types of adolescent violence that reported by par
A survey of blood parasites among members of two species of Iraqi babblers Timaliidae,
Turodoides caudatus salvadori (de Fillipi, 1865) and Turdoides alterostris (Hartert, 1909)
was carried out in the middle and south of Iraq. Two species of haematozoa were recovered,
Haemoproteus turdoidus sp. nov. and Plasmodium relictum Grassi &Felleti. The description
of the new taxon is provided and discussed with pertinent literature.
Objectives: to evaluate the role of conservative, decompression, spine fixation in management of closed spinal injury.
Methods: The study was conducted at Specialized Surgical hospital and Al-Kadhemayia Teaching Hospital, in the period between July 2003 and July 2005.The study included 61 patients categorized Into many groups according level of vertebral injury (cervical, cervicodorsal, dorsal, dorsolumbar, Lumbar and lumbosacral), type of injury (compressed fracture, burst fracture and fracture dislocation) And according the severity into three groups as G1( complete motor paralysis and sensory loss ) G2 ( complete motor paralysis and incomplete sensory loss) and G3 ( incomplete motor paralysis And incomplete sensory loss ).The metho
ABSTRACT
Ticagrelor is an orally administered antiplatelet medicine, direct-acting P2Y12-receptor antagonist. Ticagrelor binds reversibly and noncompetitively to the P2Y12 receptor at a site distinct from that of the endogenous agonist adenosine diphosphate (ADP). Inhibition of platelet aggregation stimulated by ADP is a commonly used pharmacodynamic parameter for P2Y12-receptor antagonists.
Ticagrelor is a crystalline powder with an aqueous solubility of approximately 10?g/mL at room temperature.
... Show MoreBackground: Osteoid osteomaa benign tumor is unusual before the age of 5 or after age 30 and is more prevalent in men. The main symptom is pain, which is typically severe and responsible for nocturnal awakenings. The conditons usually diagnosed through radiological imagine and confirmed by Histopathology.
Objectives: To assess the effectiveness and the complications that had been risen during the surgical procedure of osteoid osteoma using en bloc resection.
Methods: (10) Patients diagnosed with osteoid osteomawere treated with enbloc surgical reseaction were included in this study.the study took place at Al Yarmouk teaching hospital.the from April 2017-october 2018 and included 10 patients..(7) male, (3) females.The mean age of th