Power Block Off-design Control Strategies for Indirect Solar ORC Cycles

AbstractThe performance of a 5MWel indirect ORC cycle coupled to linear solar collectors with different technologies is assessed, aiming at evaluating the effect of different control strategies on annual electricity output. Two different solutions are considered for solar collectors: a state-of-the-art parabolic trough collector with Therminol VP1 as heat transfer fluid (HTF), reaching 390°C as maximum temperature within the solar field, and a cheaper Linear Fresnel Reflector (LFR) with Therminol 55, limited to an operating temperature of 310°C. A simplified procedure is firstly proposed in order to identify the organic fluid that guarantees the highest performance under design conditions. Toluene is the selected working fluid in a saturated regenerative Rankine cycle configuration. After fluid selection, a more detailed analysis involving turbine sizing and piping estimate is carried on in order to set optimal on-design parameters such as the evaporating pressure of the working fluid. Finally, yearly electricity production is calculated taking into account off-design performance of all plant components as a function of the effective solar radiation. Two different off-design control strategies are considered for the turbine, namely sliding pressure and constant pressure at the turbine inlet. The levelized cost of electricity (LCOE) is computed for both cases. For high temperature collectors the LCOE results respectively about 180 €/MWh with partial admission and 175 €/MWh with sliding pressure off-design control strategy. LFR technology leads to similar LCOE when its specific cost is about half than the parabolic trough collector

A 5-Year Randomized Controlled Study of Learning, Problem Solving Ability, and Quality of Life Modifications in People With Type 2 Diabetes Managed by Group Care

OBJECTIVE—To study time course changes in knowledge, problem solving ability, and quality of life in patients with type 2 diabetes managed by group compared with individual care and education. RESEARCH DESIGN AND METHODS—We conducted a 5-year randomized controlled clinical trial of continuing systemic education delivered by group versus individual diabetes care in a hospital-based secondary care diabetes unit. There were 120 patients with non–insulin-treated type 2 diabetes enrolled and randomly allocated to group or individual care. Eight did not start and 28 did not complete the study. The main outcome measures were knowledge of diabetes, problem solving ability, quality of life, HbA1c, BMI, and HDL cholesterol. RESULTS—Knowledge of diabetes and problem solving ability improved from year 1 with group care and worsened among control subjects (P < 0.001 for both). Quality of life improved from year 2 with group care but worsened with individual care (P < 0.001). HbA1c level progressively increased over 5 years among control subjects (+1.7%, 95% CI 1.1–2.2) but not group care patients (+0.1%, −0.5 to 0.4), in whom BMI decreased (−1.4, −2.0 to −0.7) and HDL cholesterol increased (+0.14 mmol/l, 0.07–0.22). CONCLUSIONS—Adults with type 2 diabetes can acquire specific knowledge and conscious behaviors if exposed to educational procedures and settings tailored to their needs. Traditional one-to-one care, although delivered according to optimized criteria, is associated with progressive deterioration of knowledge, problem solving ability, and quality of life. Better cognitive and psychosocial results are associated with more favorable clinical outcomes

A novel software platform for volumetric assessment of ablation completeness

Purpose: To retrospectively evaluate the accuracy of a novel software platform for assessing completeness of percutaneous thermal ablations. Materials & methods: Ninety hepatocellular carcinomas (HCCs) in 50 patients receiving percutaneous ultrasound-guided microwave ablation (MWA) that resulted in apparent technical success at 24-h post-ablation computed tomography (CT) and with ≥1-year imaging follow-up were randomly selected from a 320 HCC ablation database (2010–2016). Using a novel volumetric registration software, pre-ablation CT volumes of the HCCs without and with the addition of a 5 mm safety margin, and corresponding post-ablation necrosis volumes were segmented, co-registered and overlapped. These were compared to visual side-by-side inspection of axial images. Results: At 1-year follow-up, CT showed absence of local tumor progression (LTP) in 69/90 (76.7%) cases and LTP in 21/90 (23.3%). For HCCs classified by the software as "incomplete tumor treatments", LTP developed in 13/17 (76.5%) and all 13 (100%) of these LTPs occurred exactly where residual non-ablated tumor was identified by retrospective software analysis. HCCs classified as "complete ablation with <100% 5 mm ablative margins" had LTP in 8/49 (16.3%), while none of 24 HCCs with "complete ablation including 100% 5 mm ablative margins" had LTP. Differences in LTP between both partially ablated HCCs vs completely ablated HCCs, and ablated HCCs with <100% vs with 100% 5 mm margins were statistically significant (p < .0001 and p = .036, respectively). Thus, 13/21 (61.9%) incomplete tumor treatments could have been detected immediately, were the software available at the time of ablation. Conclusions: A novel software platform for volumetric assessment of ablation completeness may increase the detection of incompletely ablated tumors, thereby holding the potential to avoid subsequent recurrences

Mind-body relationships in elite apnea divers during breath holding: a study of autonomic responses to acute hypoxemia

The mental control of ventilation with all associated phenomena, from relaxation to modulation of emotions, from cardiovascular to metabolic adaptations, constitutes a psychophysiological condition characterizing voluntary breath-holding (BH). BH induces several autonomic responses, involving both autonomic cardiovascular and cutaneous pathways, whose characterization is the main aim of this study. Electrocardiogram and skin conductance (SC) recordings were collected from 14 elite divers during three conditions: free breathing (FB), normoxic phase of BH (NPBH) and hypoxic phase of BH (HPBH). Thus, we compared a set of features describing signal dynamics between the three experimental conditions: from heart rate variability (HRV) features (in time and frequency-domains and by using nonlinear methods) to rate and shape of spontaneous SC responses (SCRs). The main result of the study rises by applying a Factor Analysis to the subset of features significantly changed in the two BH phases. Indeed, the Factor Analysis allowed to uncover the structure of latent factors which modeled the autonomic response: a factor describing the autonomic balance (AB), one the information increase rate (IIR), and a latter the central nervous system driver (CNSD). The BH did not disrupt the FB factorial structure, and only few features moved among factors. Factor Analysis indicates that during BH (1) only the SC described the emotional output, (2) the sympathetic tone on heart did not change, (3) the dynamics of interbeats intervals showed an increase of long-range correlation that anticipates the HPBH, followed by a drop to a random behavior. In conclusion, data show that the autonomic control on heart rate and SC are differentially modulated during BH, which could be related to a more pronounced effect on emotional control induced by the mental training to BH

Sorafenib maintenance after hematopoietic stem cell transplantation improves outcome of FLT3-ITD-mutated acute myeloid leukemia

In a retrospective analysis, 21 acute myeloid leukemia patients receiving single-agent sorafenib maintenance therapy in complete remission (CR) after hematopoietic stem cell transplantation (HSCT) were compared with a control group of 22 patients without maintenance. Sorafenib was initiated a median of 3 months (IQR: 2.3–3.5) after allogeneic HSCT with a median daily dosage of 400 mg (range: 200–800) orally, and lasted a median of 11.3 months (IQR: 3.3–24.4). No significant increase in graft versus host disease or toxicity was observed. Adverse events were reversible with dose adjustment or temporary discontinuation in 19/19 cases. With a median follow-up of 34.7 months (IQR: 16.9–79.5), sorafenib maintenance significantly improved cumulative incidence of relapse (p = 0.028) as well as overall survival (OS) (p = 0.016), especially in patients undergoing allogeneic HSCT in CR1 (p < 0.001). In conclusion, sorafenib maintenance after allogeneic HSCT is safe and may improve cumulative incidence of relapse and OS in FLT3–ITD-mutated AML. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12185-022-03427-4