Heat Exchange and Separation Efficiency in a Cluster of Gas-solid Separators in a Complex Cement Production Plant

Abstract This work presents a study on a gas-solid cyclone separator used in a complex cement production plant. The main objective of the study consists on the performance evaluation and optimization of the cyclone separator in terms of particle separation and heat transfer efficiencies, while keeping pressure losses under control. The thermal interaction is between two gas-solid mixtures, one at 850 °C and the other at 600 °C, respectively. The solid phase consists mostly of calcium carbonate subsequently intended to the so-called baking process for the production of clinker and ultimately cement. A first model has been setup using experimental data as boundary conditions to assess the physical model behavior and the CFD solver parameters. After that, five additional models with different geometries have been analysed to evaluate the influence of the vortex finder ( vf ) length on the separation efficiency and on the heat exchange performance. Increasing the length of the vf , the results show a global improvement in the separation efficiency of up to 5% if compared to the geometry without the vf. Further, the increasing of the vf length determines a monotonic decrease of temperature at the exit but a monotonic increase of pressure losses. In the second part of this work, using one of the previous models with vf , a study of the influence of the particle diameter on the separation efficiency has been performed. The increaseof particle diameter causes an increase of the separation and thermal exchange performance, decreasing at the same time the pressure drop. The numerical approach for all the cases is based on implicit unsteady simulations using the Eulerian Multiphase mode

Combustion CFD modeling of a spark ignited optical access engine fueled with gasoline and ethanol

Abstract In this study we present the Computational Fluid Dynamics (CFD) modeling of the combustion process using detailed chemistry in a spark-ignited (SI) optical access engine operated at part load using gasoline and ethanol as fuels. Simulation results are compared against experimental optical and indicating data. The engine is installed at the Department of Engineering of the University of Perugia, and it features a four-valve head, a transparent flat piston and a port-fuel-injection (PFI) system. Full open cycle simulations have been performed using the commercial code CONVERGE. The combustion process has been simulated using detailed chemistry and adaptive mesh refinement (AMR) to resolve in detail and track the reaction zone, in a Reynolds Averaged Navier-Stokes (RANS) modeling framework. In-cylinder pressure, heat release, and flame morphology have been compared with experimental indicating and imaging data. Tests and simulations span different air-fuel ratios in lean and rich conditions (relative air-fuel ratio λranges from 0.9 to 1.1). Results indicate that simulations are able to predict experimental data with high accuracy. Variations due to changing fuel type and air-fuel ratio are well captured. The computational cost to achieve grid-independent results has been evaluated and it is also not excessively high. Taking into account that the engine speed was quite low, i.e., 900 rpm, we conclude that, in this condition, detailed chemistry coupled with RANS works satisfactorily without turbulence chemistry interaction sub-models, and therefore without any tunings

Econometric analysis of income mobility and wage growth

My dissertation consists in three empirical studies on income mobility and wage growth. In the first chapter I compare short run income mobility between the North and South of Italy. Using the panel of the Survey on Household Income and Wealth for the period 2004-2008, I show that individuals from the South face a worse income dynamic than those from the North even when accounting for age and education. I use a nonparametric one-sided test for comparing conditional transition probabilities with a continuous covariate. The test is based on covariate matching techniques, does not assume any functional form for the dependence of the transition probability on the covariate, allows for different sample design and has a pivotal distribution. In the second chapter I use Italian administrative data to study the effect of adverse labor market entry conditions on wage mobility of young males. I compare wage transition matrices between individuals who entered the labor market in the higher unemployment period 1986-1988 and those who entered in the lower unemployment period 1990-1992. I use a nonparametric testing procedure. I find that individuals who enter during the high unemployment period face a worse long run income mobility and in particular have signifficantly lower probabilities of reaching the top class of the wage distribution. I argue that Italy has a static labor market with a high cost of changing job. This reduces the opportunity of individuals to improve their working status, leading to a negative persistent effect of adverse entry conditions. In the third chapter I investigate the returns to internal migration for Italian young males. Using Italian administrative data I find a signifficant positive effect on wage growth in the first eleven years of career when individuals migrate towards North in the first five years of career. On the other hand I find a signifficant negative effect on the wage of the first year following migration when the destination is South. I show that it is essential to consider the destination and the timing when studying returns to migration.Programa Oficial de Doctorado en EconomíaPresidente: Carlos Velasco Gómez; Secretario: Laura Hospido Quintana; Vocal: Raquel Llorente Hera

Experimental Evaluation of a Full-Scale HVAC System Working with Nanofluid

Nowadays, energy saving is considered a key issue worldwide, as it brings a variety of benefits: reducing greenhouse gas emissions and the demand for energy imports and lowering costs on a household and economy-wide level. Researchers and building designers are looking to optimize building efficiency by means of new energy technologies. Changes can also be made in existing buildings to reduce the energy consumption of air conditioning systems, even during operational conditions without dramatically modifying the system layout and have as low an impact as possible on the cost of the modification. These may include the usage of new heat transfer fluids based on nanofluids. In this work, an extended experimental campaign (from February 2020 to March 2021) has been carried out on the HVAC system of an educational building in the Campus of University of Salento, Lecce, Italy. The scope of the investigation was comparing the COP for the two HVAC systems (one with nanofluid and the other one without) operating concurrently during winter and summer: simultaneous measurements on the two HVAC systems show that the coefficient of performance (COP) with nanofluid increased on average by 9.8% in winter and 8.9% in summer, with average daily peaks of about 15%. Furthermore, the comparison between the performance of the same HVAC system, working in different comparable periods with and without nanofluids, shows a mean increase in COP equal to about 13%

Outcome of Very Late Relapse in Patients with Hodgkin's Lymphomas

Recurrences of Hodgkin's Lymphoma (HL) 5 years after the initial therapy are rare. The aim of this study is to report a single centre experience of the clinical characteristics, outcome, and toxicity of pts who experienced very late relapses, defined as relapses that occurred 5 or more years after the achievement of first complete remission. Of 532 consecutive pts with classical HL treated at our Institute from 1985 to 1999, 452 pts (85%) achieved a complete remission. Relapse occurred in 151 pts: 135 (29.8%) within 5 years and 16 over 5 years (3.5%, very late relapses). Very late relapses occurred after a median disease-free interval of 7 years (range: 5–18). Salvage treatment induced complete remission in 14 pts (87.5%). At a median of 4 years after therapy for very late relapse, 10 pts (63%) are still alive and free of disease and 6 (37%) died (1 from progressive HL, 1 from cardiac disease, 1 from thromboembolic disease, 1 from HCV reactivation, and 2 from bacterial infection). The probability of failure-free survival at 5 years was 75%. The majority of deaths are due to treatment-related complications. Therapy regimens for very late relapse HL are warranted to minimize complications

Predictors of weight loss in patients with obesity treated with a Very Low-Calorie Ketogenic Diet

IntroductionThe Very Low-Calorie Ketogenic Diet (VLCKD) has emerged as a safe and effective intervention for the management of metabolic disease. Studies examining weight loss predictors are scarce and none has investigated such factors upon VLCKD treatment. Among the molecules involved in energy homeostasis and, more specifically, in metabolic changes induced by ketogenic diets, Fibroblast Growth Factor 21 (FGF21) is a hepatokine with physiology that is still unclear.MethodsWe evaluated the impact of a VLCKD on weight loss and metabolic parameters and assessed weight loss predictors, including FGF21. VLCKD is a severely restricted diet (<800 Kcal/die), characterized by a very low carbohydrate intake (<50 g/day), 1.2–1.5 g protein/kg of ideal body weight and 15–30 g of fat/day. We treated 34 patients with obesity with a VLCKD for 45 days. Anthropometric parameters, body composition, and blood and urine chemistry were measured before and after treatment.ResultsWe found a significant improvement in body weight and composition and most metabolic parameters. Circulating FGF21 decreased significantly after the VLCKD [194.0 (137.6–284.6) to 167.8 (90.9–281.5) p < 0.001] and greater weight loss was predicted by lower baseline FGF21 (Beta = −0.410; p = 0.012), male sex (Beta = 0.472; p = 0.011), and central obesity (Beta = 0.481; p = 0.005).DiscussionVLCKD is a safe and effective treatment for obesity and obesity related metabolic derangements. Men with central obesity and lower circulating FGF21 may benefit more than others in terms of weight loss obtained following this diet. Further studies investigating whether this is specific to this diet or to any caloric restriction are warranted

CARFILZOMIB, LENALIDOMIDE AND DEXAMETHASONE IN RELAPSED/REFRACTORY MULTIPLE MYELOMA PATIENTS: THE REAL LIFE EXPERIENCE OF RETE EMATOLOGICA PUGLIESE (REP)

Background: Carfilzomib, lenalidomide and dexamethasone (KRd) has been approved for the treatment of relapsed and refractory multiple myeloma (RRMM) based on ASPIRE clinical trial. However, its effectiveness and safety profile in real clinical practice should be further assessed. Aims: We retrospectively evaluated 120 consecutive RRMM patients treated with KRd, in 9 hematology departments of Rete Ematologica Pugliese (REP), with the aim to evaluate the efficacy and safety with KRd treatment in a real world setting. Methods: Between December of 2015 and August 2018,120 RRMM patients were analyzed.The patients’ baseline characteristics are presented in Table 1. Median patient’s age was 66 years and 41 patients(34%) were older than 70 years. The median number of previous treatment lines was 1 (range 1–11). The 94% of the patients had been already treated with bortezomib-based regimens and 33% with both lenalidomide- and bortezomib-based regimens. Moreover, half of the patients (52%) had a previous autologous stem cell transplant. The median time from the diagnosis to start of treatment with KRd was 40 months (range 5–295) and 30 patients were treated with KRd early (≤18 months from diagnosis).Disease status at the start of treatment with KRd was refractory in 33 patients(29%) and 13 patients(12%) were refractory to lenalidomide. Twenty-four patients(21%) were refractory at last therapy before KRd enrollment. Results: The overall response rate (ORR) was 84%(n = 93),with 23%(25) complete response (CR) and 50%(55) very good partial response(VGPR).The median duration of response was 12,9 months (range, 3,33– 27,7). ORR was higher in patients relapsed after a previous autologous transplant (ASCT;56% vs 37% in those relapsed without prior ASCT;p 0,05).Patients treated in late relapse had a better ORR (44%) vs those in early relapse (19%; p 0,02). After a median follow-up of 13,4 months, median PFS was not reached (NR) and 2y-PFS was 61%, Figure 1. PFS was longer in responding patients (achieving at least PR) to those with less than PR (median PFS NR vs 4,9 months;p 0,0001).Median PFS in patients relapsed after a prior ASCT was NR vs 20 months in those without prior ASCT, (p 0,002).Patients achieving ASCT after KRD had a better PFS in confront to those without ASCT (median NR vs 9 months, p 0,001).Several baseline patient characteristics, such as the III ISS scoring, older age, prior exposure to lenalidomide and early relapse were found to negatively impact PFS.Twenty-eight patients(24%) performed 4 KRd cycles as bridge treatment to ASCT. The 64% of patients reached a VGPR and 67% received ASCT, with 9 upgraded from VGPR to complete response (CR) after ASCT.The treatment discontinuation rate due to adverse events (AEs) was 13%, most commonly related to lenalidomide(8%). KRd dose reduction was necessary in 11% of patients (2,5% for carfilzomib and 8% for lenalidomide).The most frequent AE was neutropenia(43%) and anemia (41%). Infections occurred in 10% of patients.Adverse Cardiovascular toxicity (Atrial fibrillation and pulmonary hypertension)occurred in 8% of patients. Summary/Conclusion: Our analysis confirmed that KRd is effective in RRMM patients. It is well tolerated and applicable to the majority of patients outside clinical trials. A longer PFS was shown in patients 24th Congress of the European Hematology Association 276 | 2019;3:S1 achieving at least a partial response (PR), relapsing after previous ASCT and in those with the possibility to perform ASCT after KRd treatment. Accordingly,KRd should be used as an optimal bridge regimen to ASCT. Previous ASCT should not hamper the option for KRd therap