Does the Oil Revenues Affect the Macro Economic Variables\u27 Performance in Africa? a Panel Data Analysis

Oil revenues play a vital and central role in the economies of developing countries and African countries are among the countries whose macroeconomic variables are affected by oil revenues. The objective of this study is to analyze and investigate the role of oil revenues on the macroeconomic variables in most of the oil-producing African countries. The Econometric method Pooled Ols model was employed in the study and the fixed and random technique data used was time sires cross panel data in the period (2000-2018). Based on the literature review, the selected  sample study was on countries such as (Nigeria, Algeria, Angola, Gabon, Egypt, Congo, Egypt, Congo, Sudan, Chad, Ghana) and we employed the Gross Domestic Product as the target variable and Oil Revenues (Oiler), inflation (CPI), Exchange rate (Ex), export (Exp), Foreign Direct Invest (FDI), money supply (M2), as independent variables. The study result and analysis of the data indicated that oil revenue has an impact on most the macroeconomic variables in the study except CPI and money supply. The study also indicated a strong positive correlation between oil revenue and GDP growth rate on the countries samples study. The study concluded that one of the most important macroeconomic variables is oil revenues. It also recommended that African countries need support and need to put more effort in building strong economies that are not dependent on oil revenues; to work on diversifying the revenues of the states and work to preserve the right of the next generation to exploit natural and oil resources

Reconstruction of maxillofacial bone defects: Contemporary methods and future techniques

Reconstruction of maxillofacial continuity defects has always been a challenging tasks for the scientist and surgeons over the years. The main goal of the reconstruction of the maxillofacial region is to restore facial form, function, full rehabilitation of occlusion and articulation. A refinement in surgical technique and methods of reconstruction has improved patient’s quality of life. This manuscript reviewed exciting methods of bone reconstruction and confirms that the ideal system for reconstruction of critical size continuity defect of the jaw bones has yet to be found. Shortcoming and limitation of each method has been discussed. The author highlight recent advances on how tissue engineering which could offer biological substitute to restore, maintain, or improve oro-facial function

Pressure fluctuations on the surface of a cylinder in uniform flow

The problem of determining the pressure fluctuations induced on the surface of a cylinder by the fluctuating wake behind it is formulated. A formal solution relating the unsteady surface pressure field to the velocity field in the wake is derived and used to obtain general results independent of cylinder shape and Reynolds number. The case of the circular cylinder is then examined in detail

Coupled thermo-mechanical damage modelling for structural steel in fire conditions

This paper aims at developing a coupled thermo-mechanical damage model for structural 6 steel at elevated temperatures. The need for adequate modelling of steel deterioration behaviour 7 remains a challenging task in structural fire engineering because of the complexity inherent in 8 the damage states of steel under combined actions of mechanical and fire loading. A fully three9 dimensional damage-coupled constitutive model is developed in this work based on the hypothesis 10 of effective stress space and isotropic damage theory. The new coupling model, adapted from 11 an enhanced Lemaitre’s ductile damage equation and taking into account temperature-dependent 12 thermal degradation, is a phenomenological approach where the underlying mechanisms that govern 13 the damage processes have been retained. The proposed damage model comprises a limited number 14 of parameters that could be identified using unloading slopes of stress-strain relationships through 15 tensile coupon tests. The proposed damage model is successfully implemented in the finite element 16 software ABAQUS and validated against a comprehensive range of experimental results. The 17 damage-affected structural response is accurately reproduced under various loading conditions and 18 a wide temperature range, demonstrating that the proposed damage model is a useful tool in giving a 19 realistic representation of steel deterioration behaviour for structural fire engineering applications

The accuracy of three-dimensional prediction of soft tissue changes following the surgical correction of facial asymmetry: an innovative concept

The accuracy of three-dimensional (3D) predictions of soft tissue changes in the surgical correction of facial asymmetry was evaluated in this study. Preoperative (T1) and 6–12-month postoperative (T2) cone beam computed tomography scans of 13 patients were studied. All patients underwent surgical correction of facial asymmetry as part of a multidisciplinary treatment protocol. The magnitude of the surgical movement was measured; virtual surgery was performed on the preoperative scans using Maxilim software. The predicted soft tissue changes were compared to the actual postoperative appearance (T2). Mean (signed) distances and mean (absolute) distances between the predicted and actual 3D surface meshes for each region were calculated. The one-sample t-test was applied to test the alternative hypothesis that the mean absolute distances had a value of <2.0 mm. A novel directional analysis was applied to analyse the accuracy of the prediction of soft tissue changes. The results showed that the distances between the predicted and actual postoperative soft tissue changes were less than 2.0 mm in all regions. The predicted facial morphology was narrower than the actual surgical changes in the cheek regions. 3D soft tissue prediction using Maxilim software in patients undergoing the correction of facial asymmetry is clinically acceptable

An experimental investigation of the flow past a finite circular cylinder at a low subcritical Reynolds number

Results of hot wire measurements made in the near wake at a Reynolds number of 9955 are reported. The measurements include the mean velocity profiles, root mean square values of the velocity fluctuations, frequency spectra, and velocity cross correlations. The mean velocity profiles were used to determine the wake width, whose variation in the downstream and spanwise directions was examined. It is observed that close to the cylinder, the wake is narrower toward the free end than it is away from it, while further downstream the wake is wider toward the tip than it is away from it. It is found that the flow over the span can be characterized by four regions: a tip region where vortex shedding occurs at a lower frequency than that prevalent for away from the tip; an intermediate region adjacent to the first one where a frequency component of a nonshedding character is present; a third region characterized by a gradually increasing shedding frequency with increasing distance from the tip; and a two dimensional region where the shedding frequency is constant

Accuracy of generic mesh conformation: the future of facial morphological analysis

Three-dimensional (3D) analysis of the face is required for the assessment of changes following surgery, to monitor the progress of pathological conditions and for the evaluation of facial growth. Sophisticated methods have been applied for the evaluation of facial morphology, the most common being dense surface correspondence. The method depends on the application of a mathematical facial mask known as the generic facial mesh for the evaluation of the characteristics of facial morphology. This study evaluated the accuracy of the conformation of generic mesh to the underlying facial morphology. The study was conducted on 10 non-patient volunteers. Thirty-four 2-mm-diameter self-adhesive, non-reflective markers were placed on each face. These were readily identifiable on the captured 3D facial image, which was captured by Di3D stereophotogrammetry. The markers helped in minimising digitisation errors during the conformation process. For each case, the face was captured six times: at rest and at the maximum movements of four facial expressions. The 3D facial image of each facial expression was analysed. Euclidean distances between the 19 corresponding landmarks on the conformed mesh and on the original 3D facial model provided a measure of the accuracy of the conformation process. For all facial expressions and all corresponding landmarks, these distances were between 0.7 and 1.7 mm. The absolute mean distances ranged from 0.73 to 1.74 mm. The mean absolute error of the conformation process was 1.13 ± 0.26 mm. The conformation of the generic facial mesh is accurate enough for clinical trial proved to be accurate enough for the analysis of the captured 3D facial images

Assessment of facial asymmetry before and after the surgical repair of cleft lip in unilateral cleft lip and palate cases

This study was performed to assess facial asymmetry in patients with unilateral cleft lip and palate (UCLP) before and after primary lip repair. Three-dimensional facial images of 30 UCLP cases (mean age 3.7 ± 0.8 months) captured 1–2 days before surgery and 4 months after surgery using stereophotogrammetry were analysed. A generic mesh – a mathematical facial mask consisting of thousands of points (vertices) – was conformed on the three-dimensional images. Average preoperative and postoperative conformed facial meshes were obtained and mirrored by reflecting on the lateral plane. Facial asymmetry was assessed by measuring the distances between the corresponding vertices of the superimposed facial meshes. Asymmetries were further examined in three directions: horizontal, vertical, and anteroposterior. Preoperatively, the philtrum and bridge of the nose were deviated towards the non-cleft side. The maximum vertical asymmetry was at the upper lip. The greatest anteroposterior asymmetry was at the alar base and in the paranasal area. The overall facial asymmetry improved markedly after surgery. Residual anteroposterior asymmetry was noted at the alar base, upper lip, and cheek on the cleft slide. In conclusion, dense correspondence analysis provided an insight into the anatomical reasons for the residual dysmorphology following the surgical repair of cleft lip for future surgical consideration

Mixed Formulation of Inelastic Composite Shear Beam Element

This study presents a new beam element formulation following a Hellinger-Reissner functional for composite members considering coupling between bond-slip and shear deformations. A robust state determination along with new stability criteria for the mixed-based formulation is proposed. The constitutive laws of the concrete, steel, and shear connectors are used to derive the inelastic coupled axial-flexural-shear interaction of the composite element. To consider shear deformations, a Timoshenko beam theory has been adopted in deriving the section kinematics equations. J2 plasticity following radial return mapping algorithm and fixed crack smeared softened membrane model are used to simulate the multi-axial stress state in steel and concrete respectively. The accuracy and efficiency of the mixed-based formulation wasevaluated by comparing the responses at local and global levels with the displacement-based formulation

Factors affecting employment during crisis in private businesses in Kurdistan

The main aim of this study is to investigate the critical factors that effecting employment during crisis in private businesses in Kurdistan. An empirical quantitative technique utilized to analyze the present research. The researcher applied a random sampling method, where all respondents had equal chances of being selected for the sample. The research was carried out at 18 private businesses in Erbil. The population of this research was approximately 341 employees, accordingly to cover the entire research population; 100 surveys were distributed but 84 forms were collected that were accomplished accurately. The results showed that the highest value was for economic factor this means that economic is strongly related to employment and has strong influence on employment during crisis in private businesses in Kurdistan