The primary objective of this study is to investigate the solar-powered combined-cycles system in order to convert the available solar energy to its truest potential and generate electrical power. This combined-cycles system consists of solar power tower, steam turbine cycle, and organic Rankine cycle. The study focused on recovering the waste heat which is obtained from the exit of a steam turbine and uses it to operate the Rankine cycle by using the refrigerants, R-113, R-11, and R-1233zd. The analysis also predetermines the effects of solar irradiance for a mass flow rate of molten salt and steam, turbine inlet pressure, and turbine inlet temperature on first and second law efficiencies in the combined-cycles system. The novel concept of uncertainty analysis is also introduced in this work in order to provide accurate result with precision and removing all errors, which is found out to be 3.81 % that is in the desired range. The results also show that as the direct normal irradiation (DNI) increases from (600 W/m2 to 1000 W/m2), first law efficiency is obtained in the range of (32.31% to 37.99%) and second law from (24.14 % to 25.51 %) after employing the organic Rankine cycle (ORC) system. Further, the result indicates that maximum exergy destruction that occurs in the central receiver is around 42%, heliostat is 31%, the steam generator is 10%, a heat exchanger is 3.6%, etc.
The new bridge over the Drini River, along the Milot-Morine highway near the city of Kukes in Albania, is a strategically important project for the development of the region, where access to Kukes was previously limited by the historic reinforced concrete bridge. Given the length of the main span, 270 meters, making the bridge one of the largest tie-arch structures in Europe, the project underwent thorough design evaluations aimed at minimizing structural weight and foundation loads. Architecturally, the slender arch shape, combined with the use of weathering steel, was preferred as it was deemed optimal for landscape integration. The construction phases were developed in parallel with the bridge project, as they were a critical aspect in a region with very few areas suitable for pre-assembling the structure.
Purpose To estimate the prevalence of keratoconus in a population of subjects undergoing first eye examination in an eye clinic in Italy.Methods A single-center, cross-sectional, study was conducted involving patients who underwent first eye examination at an eye clinic in Rome between September 2021 and June 2022. The prevalence of keratoconus was determined by Placido-disk corneal topography using the maximum keratometry (Kmax) value and the Cone Magnitude and Location Index (CLMI) for keratoconus screening. Subjective analysis was performed by two experienced corneal specialists, who classified the outcome into two groups: normal and keratoconus. Risk factors, including family history of keratoconus, allergy or atopy, thyroid disease, eye rubbing habit and gender were also examined.Results A total of 512 subjects between 7 and 81 years old were evaluated. The inter-observer agreement to classify subjects in normal or keratoconus group was excellent (k = 1.0); the estimated prevalence in the specific population was 2.1%. Presence of positive family history (9% of keratoconus vs 5% normal), concomitant allergy or atopy (27% vs 9%) and eye rubbing habit (18% vs 4%) were associated with a higher risk of disease.Conclusion This study reported a high estimated prevalence of keratoconus in a metropolitan area of Italy, as found in recent studies in the Mediterranean and Middle East countries. Screening for keratoconus is highly recommendable and easily feasible with corneal topography under expert supervision and may be indicated primarily in young population to improve early detection and prompt therapeutic management for halting disease progression.
ObjectiveTo report variants in 26 candidate genes and describe the clinical features of Italian patients with keratoconus (KC).Subjects/methodsSixty-four patients with a confirmed diagnosis of KC were enrolled in this genetic association study. Patients were classified into two study groups according to whether they had a confirmed diagnosis of progressive or stable KC. A purpose-developed Next Generation Sequencing (NGS) panel was used to identify and analyse the coding exons and flanking exon/intron boundaries of 26 genes known to be associated with KC and corneal dystrophies. Interpretation of the pathogenic significance of variants was performed using in silico predictive algorithms.ResultThe targeted NGS research identified a total of 167 allelic variants of 22 genes in the study population; twenty-four patients had stable keratoconus (n. 54 variants) and forty patients had progressive disease (n. 113 variants). We identified genetic variants of certain pathogenic significance in five patients with progressive KC; in addition, eight novel genetic variants were found in eight patients with progressive KC. Mutations of FLG, LOXHD1, ZNF469, and DOCK9 genes were twice more frequently identified in patients with progressive than stable disease. Filaggrin gene variants were found in 49 patients (76% of total), of whom 32 patients (80% of progressive KC group) had progressive disease.ConclusionsTargeted NGS research provided new insights into the causative effect of candidate genes in the clinical phenotype of keratoconus. Filaggrin mutations were found to represent a genetic risk factor for development of progressive disease in Italy.
