The College of Education for Pure Sciences, Department of Mathematics, discussed a doctoral thesis on (A numerical study of the effect of constrictions and some materials on blood flow in arteries). The thesis presented by the researcher (Mohammed Sabah Abdel Wahab) included a study in which two new methods were presented to find approximate analytical solutions to nonlinear problems. The two new methods were used to study various problems, such as blood flow in a narrow artery under the influence of a magnetic field, blood flow in a narrow artery under the influence of electroosmosis, and blood flow in a narrow artery with the presence of nanomaterials (gold, graphene). In addition, a new study was presented, which is a study of the effect of hybrid nanomaterials (gold - graphene) on blood flow in narrowed arteries. In all these problems, the effect of many of their important parameters was discussed according to each problem, such as the magnetic field parameter, the electroosmosis parameter, the nanoparticle particle size parameter, the artery tilt angle parameter, the porosity parameter, the constriction size parameter, and the chemical reaction parameter, on basic flow properties such as speed, temperature distribution, and concentration. The thesis concluded that the two proposed new methods are powerful and effective mathematical tools in studying nonlinear problems as well as blood flow problems in stenotic arteries. In addition, these results can be medically exploited through the use of hybrid nanomaterials and employed in the treatment of atherosclerosis patients or in the process of delivering drugs to the targeted areas.