End Loss Research Articles

A high-performance all-day vertical thermoelectric generator based on a double-sided reflective structure

Harvesting environmental energy sources is crucial for achieving renewable energy generation and net-zero emissions. However, ensuring uninterrupted electricity generation from environmental energy sources remains challenging. In this study, we present a simple, compact, and expandable all-day vertical passive thermoelectric generator (V-TEG) with a double-sided reflective structure that simultaneously harnesses solar and space cold energy. Outdoor experimental measurements, combined with finite element simulation analysis, revealed that the optimal angles of the solar reflector relative to the TEG range from 30° to 50°. Additionally, the TEG placed in the north–south orientation was found to enhance its daytime performance. The use of low-cost black paint combined with the solar reflector achieved equivalent spectral selectivity, effectively minimizing the infrared heat loss of the hot end of the TEG. During a 48-h outdoor test, the V-TEG achieved an average daytime power of 112.00 mW/m2 and a peak of 363.42 mW/m2. Comparative experiments demonstrated that the V-TEG outperformed horizontally placed TEG during the daytime. Furthermore, scaling the system by connecting three TEGs in series significantly increased the daily power output. This compact V- TEG system offers a promising solution for long-term power generation in low-power sensors and off-grid communities, supporting renewable energy and carbon neutrality goals.

Axial confinement of wire array Z-pinch precursor plasmas by a pulsed magnetic mirror field

A novel wire-array Z-pinch platform has been developed to study the effect of a pulsed magnetic mirror field on a collisional high energy density plasma. The mirror is driven in series with the Z-pinch target and, therefore, scales with driver current. Axial confinement is observed based on visible imaging and axial flow velocity measurements. The presence of axial compressing J ×B force is determined indirectly based on Thomson scattering and interferometry measurements and corroborated by three-dimensional extended-MHD simulations. Compared to non-magnetized wire array Z-pinch, a modified pulsed mirror configuration is observed to increase precursor plasma thermal energy density by about 30%. If optimized, such a configuration could potentially improve magnetized liner inertial fusion performance by reducing axial plasma end loss.

Stem Cells and Stem Cell-Derived Factors for the Treatment of Inflammatory Bowel Disease with a Particular Focus on Perianal Fistulizing Disease: A Minireview on Future Perspectives.

Inflammatory bowel disease remains a difficult disease to effectively treat, especially fistulizing Crohn's disease. Perianal fistulas in the setting of Crohn's disease remain an area of unmet need with significant morbidity in this patient population. Up to one third of Crohn's patients will have perianal fistulizing disease and current medical and surgical interventions are of limited efficacy. Thus, most patients experience significant morbidity, narcotic use, and loss of employment and end up with multiple surgical interventions. Mesenchymal stem cells (MSCs) have shown efficacy in phase 3 clinical trials, but considerable infrastructure challenges make MSCs limited with regard to scalability in clinical practice. Extracellular vesicles, being derived from MSCs and capturing the secretome functionality of MSCs, offer similar physiological utility regarding mechanism, while also providing an off the shelf regenerative medicine product that could be widely used in daily clinical practice.

Demand response of large-scale residential load to concentrated variable renewable energy

Large-scale concentrated Variable Renewable Energy (VRE) sources pose a challenge to the balance and security of electricity systems. Studies have shown that the demand side may offer a greater responsiveness based on the shiftability of loads. However, there is currently no known literature on the demand response (DR) of large-scale shiftable loads in the residential sector. Firstly, there is no sufficiently large database of residential appliance-level load. Secondly, scheduling a large number of small residential shiftable loads simultaneously is a major challenge. Ultimately, the DR of large-scale residential buildings encounters the challenge of ensuring sufficient backup shiftable load to effectively cope with real-time VRE fluctuations during the response period. To address these issues, this paper proposes an appliance-level load data generation method based on diffusion neural networks. Meanwhile, a clustering method based on Generalized End to End (GE2E) loss neural networks is proposed to solve the complexity obstacles in simultaneous load swarm scheduling. Thirdly, a two-stage scheduling approach is proposed to address the challenges in the large-scale DR period through constructing day-ahead and real-time response models. The simulation results show that large-scale residential shiftable loads have a strong response capability to VRE fluctuations, and their response cost is lower than the conventional fuel-fired-power-plant-based-response within a certain user preference cost range. In practice, the clustering and scheduling methods proposed in this paper can be applied after the non-intrusive load monitoring (NILM) method is deployed to decompose the load data.

Optimization and Testing of DC Electromagnetic Pump for Liquid Metal Space Use

Driving a liquid metal via an electromagnetic pump (EMP) is becoming increasingly important with its many emerging cutting-edge uses. The end losses associated with the EMP generally play a core role in dominating device performance. In this study, we explored the effects of electrode width, number of insulating strips, and pump width on the end loss through theoretical analysis and numerical simulations. The optimization results indicate that reducing electrode width would improve EMP performance. Adding insulation strips enhances the magnitude and uniformity of effective current density but raises hydraulic losses. A smaller pump width achieves a stronger static head, while a larger pump width outputs a higher flow rate. Furthermore, 3D printing technology was employed for rapid integrated processing of the pump body. Detailed performance evaluations and reliability tests were carried out on the EMP. With the design optimized so as to minimize the end losses, an EMP for space experiments has been successfully developed, which will eventually be flown on the China’s space station. Overall, the feasibility of fast, low-cost manufacturing of high-reliability, compact EMP with the assistance of numerical simulation and 3D printing technology was demonstrated. It provides an alternative option for driving metallic fluid for various future space needs.

Impact of double-axis tracking on thermal performance of the linear Fresnel Collector: An experimental study

Due to the concerning trend of fossil fuels destructive effect on the environment, renewables, especially solar energy, can be a promising alternative to meet the world's energy demands. Linear Fresnel Collectors (LFCs) are solar thermal collectors that can effectively provide the required thermal energy for various applications. Despite the low capital cost and non-complicated structure of the LFCs, they have some drawbacks, such as end loss effects that reduce their optical and thermal efficiencies. The current research introduces a mechanical tracking system to enable the system to rotate in the secondary axis to decrease the end loss effect. Four experimental tests at laminar and turbulent flows in two single and double-axis tracking modes have been performed to investigate the non-illuminated length in each scenario. Moreover, a theoretical study was conducted, and the results were compared with the experiments. The results showed that the thermal efficiencies were 8.67 %–22.03 % and 40.97 %–63.5 % for the double-axis tracking mode in laminar and turbulent, respectively. The double-axis tracking system enhanced the system's thermal efficiency by 18.91 % and 6.42 % for laminar and turbulent flows on average, respectively, compared to the single-axis tracking. Furthermore, the difference between the experimental and theoretical non-illuminated length values was calculated as 4.14 % and 8.44 % on average for laminar and turbulent flows, respectively. Finally, according to the economic analysis, 4.78 years was calculated for the payback time of the investigated system.

Analysis of leakage flux, losses, and temperature in large synchronous generator end zone under the multi‐layer screen thickness based on novel iterative method

AbstractThe multi‐layer screen is the key component in the large synchronous generator end zone. The leakage flux, losses, and temperature of end components are significantly affected by the thickness of multi‐layer screen in the synchronous generator. To investigate the influence of multi‐layer screen thickness on the end leakage flux, losses, and temperature in the synchronous generator end zone, 1407MVA nuclear power synchronous generator is studied. Three‐dimensional transient electromagnetic field model of synchronous generator end zone is established. Three‐dimensional transient electromagnetic field in the end zone of 1407MVA synchronous generator with the multi‐layer screen is calculated based on the novel iterative method. The flux density of end components is compared and studied in the end zone under the variation of multi‐layer screen thickness. Influence of the different thicknesses of multi‐layer screen on the losses of the shield plate, screen, finger plate, and stator end core is researched. The losses of end components obtained from 3D end electromagnetic field calculation are applied to the end zone as the heat source in the three‐dimensional fluid and thermal coupled field. The temperature distribution of the end components is determined. The accuracy of the calculated results is validated by the experimental values.

Association of Medication-Assisted Therapy and Risk of Drug Overdose-Related Hospitalization or Emergency Room Visits in Patients With Opioid Use Disorder.

Objective To examine the differential impacts of medication-assisted therapy (MAT) medications (naltrexone, methadone, and buprenorphine) on drug overdose-related hospitalizations or emergency room (ER) visits in patients with opioid use disorder (OUD). Patients and methods A retrospective cohort study was performed on patients 18 years or older diagnosed with OUD, using Optum's de-identified Clinformatics® Data Mart database. To ensure a new diagnosis of OUD from 2018 to 2019, each patient required one year of continuous enrollment before OUD diagnosis. The primary outcome was the incidence of drug overdose-related hospitalization or ER visits in the follow-up period. Patients were censored at loss of coverage or end of the study (9/30/2020). A multivariable Cox proportional hazard model was built to compare the outcomes across three MAT medications (buprenorphine, methadone, and naltrexone). Results Only 10.38% of the 145,317 OUD patients received MAT prescriptions in the 12 months after diagnosis. The majority of MAT users (77.8%) received buprenorphine. At one year of follow-up, the incidence of drug overdose-related hospitalization or ER visits varied by MAT drug type: naltrexone (14.26%), methadone (12.26%), and buprenorphine (10.23%). Compared to methadone drug users, buprenorphine users had a lower risk of negative outcomes (adjusted hazard ratio: 0.84; 95% confidence interval: 0.73-0.97). Conclusion Buprenorphine was associated with the lowest risk of drug overdose-related hospitalization or ER visits among the MAT drugs. However, only 10.38% of OUD patients received MAT. Increasing MAT availability to patients with OUD is a key step towardpreventing relapse and reducing adverse health outcomes.

Mixtures of long-term exposure to ambient air pollution, built environment and temperature and stroke incidence across Europe

IntroductionThe complex interplay of multiple environmental factors and cardiovascular has scarcely been studied. Within the EXPANSE project, we evaluated the association between long-term exposure to multiple environmental indices and stroke incidence across Europe. MethodsParticipants from three traditional adult cohorts (Germany, Netherlands and Sweden) and four administrative cohorts (Catalonia [region Spain], Rome [city-wide], Greece and Sweden [nationwide]) were followed until incident stroke, death, migration, loss of follow-up or study end. We estimated exposures at residential addresses from different exposure domains: air pollution (nitrogen dioxide (NO2), particulate matter < 2.5 μm (PM2.5), black carbon (BC), ozone), built environment (green/blue spaces, impervious surfaces) and meteorology (seasonal mean and standard deviation of temperatures). Associations between environmental exposures and stroke were estimated in single and multiple-exposure Cox proportional hazard models, and Principal Component (PC) Analyses derived prototypes for specific exposures domains. We carried out random effects meta-analyses by cohort type. ResultsIn over 15 million participants, increased levels of NO2 and BC were associated with increased higher stroke incidence in both cohort types. Increased Normalized Difference Vegetation Index (NDVI) was associated with a lower stroke incidence in both cohort types, whereas an increase in impervious surface was associated with an increase in stroke incidence. The first PC of the air pollution domain (PM2.5, NO2 and BC) was associated with an increase in stroke incidence. For the built environment, higher levels of NDVI and lower levels of impervious surfaces were associated with a protective effect [%change in HR per 1 unit = −2.0 (95 %CI, −5.9;2.0) and −1.1(95 %CI, −2.0; −0.3) for traditional adult and administrative cohorts, respectively]. No clear patterns were observed for distance to blue spaces or temperature parameters. ConclusionsWe observed increased HRs for stroke with exposure to PM2.5, NO2 and BC, lower levels of greenness and higher impervious surface in single and combined exposure models.

Observational study of HR+/HER2− metastatic breast cancer patients treated with abemaciclib in Spain in the Named Patient Use Program (AbemusS)

Introduction/objectivesTo describe abemaciclib use in patients with hormone receptor-positive, human epidermal growth factor receptor-negative (HR+/HER2−) metastatic breast cancer (mBC) who participated in the Named Patient Use program (NPU) in Spain.Material and methodsThis retrospective study was based on medical record review of patients across 20 centers during 2018/2019. Patients were followed up until death, enrolment in a clinical trial, loss of follow-up or study end. Clinical and demographic characteristics, treatment patterns and abemaciclib effectiveness were analyzed; time-to-event and median times were estimated using the Kaplan–Meier (KM) method.ResultsThe study included 69 female patients with mBC (mean age 60.4 ± 12.4 years), 86% of whom had an initial diagnosis of early BC and 20% had an ECOG ≥ 2. Median follow-up was 23 months (range 16–28). Metastases were frequently observed in bone (79%) and visceral tissue (65%), with 47% having metastases in > 2 sites. Median number of treatment lines before abemaciclib was 6 (range 1–10). Abemaciclib monotherapy was received by 72% of patients and combination therapy with endocrine therapy by 28% of patients; 54% of patients required dose adjustments, with a median time to first adjustment of 1.8 months. Abemaciclib was discontinued in 86% of patients after a median of 7.7 months (13.2 months for combination therapy and 7.0 months for monotherapy) mainly due to disease progression (69%).ConclusionThese results suggest that abemaciclib is effective, as monotherapy and in combination, for patients with heavily pretreated mBC, consistent with clinical trial results.

Methane-assisted catalytic light oil desulfurization: Catalyst design, sulfur product distribution analysis and mechanistic study

The desulfurization of natural oil feedstock for fuel purposes is crucial for environmental protection and sustainable development. Methane is the main component of natural gas resources with low added value. Distinctive characteristics are demonstrated if methane can be directly used for oil desulfurization, instead of being converted into hydrogen via methane stream reforming for hydrodesulfurization. Here, the methane-assisted catalytic desulfurization process is specifically developed for light oils such as marine diesel oil. First, different catalyst supports are selected and compared, among which Al2O3 is confirmed to provide the most favorable reaction performances. Then, the reaction is operated under different gas atmospheres including CH4, N2, and H2, to reveal the uniqueness of methane for a desulfurization process. Next, model compound oils are selected with thiophene as the sulfur-containing oil component. Heptane and toluene are used as solvents to represent paraffin-rich and aromatic-rich oil, respectively. It is found that the structural characteristic of the oil significantly influences the desulfurization performance and product distribution, based on which the respective reaction mechanism networks are proposed. It is concluded that despite the unparalleled desulfurization performance under hydrogen, the methane-assisted desulfurization process demonstrates distinctive characteristics to prevent light end loss and oversaturation as well as the formation of H2S as the primary desulfurization product, which can be better utilized under certain circumstances.

Exploring the parameter space of MagLIF implosions using similarity scaling. III. Rise-time scaling

Magnetized liner inertial fusion (MagLIF) is a z-pinch magneto-inertial-fusion concept studied at the Z Pulsed Power Facility of Sandia National Laboratories. Two important metrics characterizing current delivery to a z-pinch load are the peak current and the current-rise time, which is roughly the time interval to reach the peak current. It is known that, when driving a z-pinch load with a longer current-rise time, the performance of the z-pinch decreases. However, a theory to understand and quantify this effect is still lacking. In this paper, we utilize a framework based on similarity scaling to analytically investigate the variations in the performance of MagLIF loads when varying the current-rise time, or equivalently, the implosion timescale. To maintain similarity between the implosions, we provide scaling prescriptions of experimental input parameters defining a MagLIF load and derive the expected scaling laws for stagnation conditions and for various performance metrics. We compare predictions of the theory to 2D numerical simulations using the radiation, magneto-hydrodynamic code hydra. For several metrics, we find acceptable agreement between the theory and simulations. Our results show that the voltage φload near the MagLIF load follows a weak scaling law φload∝tφ−0.12 with respect to the characteristic timescale tφ of the voltage source, instead of the ideal φload∝tφ−1 scaling. This occurs because the imploding height of the MagLIF load must increase to preserve end losses. As a consequence of the longer imploding liners, the required total laser preheat energy and delivered electric energy increase. Overall, this study helps understand the trade-offs of the MagLIF design space when considering future pulsed-power generators with shorter and longer current-rise times.

Design and Analysis of a Hybrid Displacement Amplifier Supporting a High-Performance Piezo Jet Dispenser

In this study, a compliant amplifier powered by a piezoelectric stack is designed to meet high-performance dispensing operation requirements. By studying the issue of low frequency bandwidth on the traditional bridge-type amplifier mechanism, we propose a displacement amplifier mechanism, hybrid bridge-lever-bridge (HBLB), that enhances its dynamic performance by combining the traditional bridge-type and lever mechanism. A guiding beam is added to further improve its output stiffness with a guaranteed large amplification ratio. An analytical model has been developed to describe the full elastic deformation behavior of the HBLB mechanism that considers the lateral displacement loss of the input end, followed by a verification through a finite element analysis (FEA). Results revealed that the working principle of the HBLB optimizes the structural parameters using the finite element method. Finally, a prototype of the displacement amplifier was fabricated for performance tests. Static and dynamic test results revealed that the proposed mechanism can reach a travel range of 223.2 μm, and the frequency bandwidth is 1.184 kHz, which meets the requirements of a high-performance piezo jet dispenser.

COMPARATIVE EFFECTS OF BIOLOGICS IN PREVENTING PENETRATING COMPLICATIONS IN CROHN’S DISEASE

Abstract BACKGROUND Comparative efficacy of biologics is an important consideration when selecting therapies for Crohn’s disease (CD). While recent studies have focused on clinical remission, few studies have assessed the comparative efficacy of biologics in preventing penetrating disease (PD) complications of CD. The aim of our study was to compare the rates of penetrating complications (luminal and perianal) between biologics used as first-line therapies in CD. METHODS A propensity-score adjusted retrospective comparative effectiveness study was performed using IBM® MarketScan® Commercial Database (2006-2020). We included adults (≥18 years) with CD (≥3 administrative claims for CD [K50.*]) who initiated their first biologic (anti-tumor necrosis factor [anti-TNF], ustekinumab ([UST]) or vedolizumab [VDZ]). with ≥ 2 consecutive years of health insurance enrollment during study period (at least 1 year following index date). Patients with pre-existing luminal penetrating disease (LPD) or perianal penetrating disease (PPD) or prior biologic exposure were excluded using a minimum look-back period of 1 year. LPD was identified by ICD claims (537.4, 567.2X, 569.X, 593.82, 596.1, 619.1, K31.6, K65.X, K63.X, N82, N32.1) and PPD by a validated case definition. Patients were followed until a PD event and censored if a new biologic class was initiated, loss of medical coverage or study end. Cohorts were balanced by inverse probability of treatment weighting based on age, sex, Elixhauser comorbidity score, and prior CD surgery. Pairwise comparisons of biologic classes were performed by cox-proportional hazard models with medication exposure treated as a time-dependent variable based on a medication possession ratio of 0.8. RESULTS A total of 40693 patients with CD without prior penetrating disease (54.1% female, median age 39 years [IQR; 28-50]) initiated biologic therapy: 37839 (93.0%) anti-TNF, 1194 (3.0%) UST and 1660 (4.0%) VDZ. Penetrating complications developed in 8567 (21.1%) patients: 2,204 (5.4%) LPD and 7,474 (18.4%) PPD. Compared with no medication exposure, anti-TNFs were protective against composite (Figure 1, HR 0.91; 95% confidence interval (CI), 0.84 - 0.98, p = 0.013) and LPD (HR 0.59; CI, 0.50 - 0.69; p &amp;lt;.0001) but not PPD (HR, 0.99; CI, 0.91 - 1.07; p = 0.78). Neither VDZ nor UST were protective against composite, LPD or PPD. In pairwise comparisons, anti-TNF was significantly protective against composite (Figure 2, HR 0.92; CI, 0.85 – 0.99; P = 0.018) and LPD (HR 0.51; CI, 0.44 – 0.60; p &amp;lt;.0001) compared with VDZ and for LPD compared with UST (HR, 0.71; CI, 0.61 – 0.83, p &amp;lt;.0001). CONCLUSIONS Anti-TNF therapy was protective against developing LPD and may offer an advantage over VDZ and UST in preventing this disease complication. Further studies are needed to validate these findings and to determine potential reasons for these differences. Figure 1: Comparison of biologics in preventing the composite outcome of penetrating complications in patients with Crohn's disease. Figure 2: Comparison of anti-TNF versus vedolizumab in preventing composite outcome of penetrating complications in patients with Crohn's disease

Comparative effectiveness of different primary vaccination courses on mRNA-based booster vaccines against SARs-COV-2 infections: a time-varying cohort analysis using trial emulation in the Virus Watch community cohort.

The Omicron B.1.1.529 variant increased severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections in doubly vaccinated individuals, particularly in the Oxford-AstraZeneca COVID-19 vaccine (ChAdOx1) recipients. To tackle infections, the UK's booster vaccination programmes used messenger ribonucleic acid (mRNA) vaccines irrespective of an individual's primary course vaccine type, and prioritized the clinically vulnerable. These mRNA vaccines included the Pfizer-BioNTech COVID-19 vaccine (BNT162b2) the Moderna COVID-19 vaccine (mRNA-1273). There is limited understanding of the effectiveness of different primary vaccination courses on mRNA booster vaccines against SARs-COV-2 infections and how time-varying confounders affect these evaluations. Trial emulation was applied to a prospective community observational cohort in England and Wales to reduce time-varying confounding-by-indication driven by prioritizing vaccination based upon age, vulnerability and exposure. Trial emulation was conducted by meta-analysing eight adult cohort results whose booster vaccinations were staggered between 16 September 2021 and 05 January 2022 and followed until 23 January 2022. Time from booster vaccination until SARS-CoV-2 infection, loss of follow-up or end of study was modelled using Cox proportional hazard models and adjusted for age, sex, minority ethnic status, clinically vulnerability and deprivation. A total of 19 159 participants were analysed, with 11 709 ChAdOx1 primary courses and 7450 BNT162b2 primary courses. Median age, clinical vulnerability status and infection rates fluctuate through time. In mRNA-boosted adults, 7.4% (n = 863) of boosted adults with a ChAdOx1 primary course experienced a SARS-CoV-2 infection compared with 7.7% (n = 571) of those who had BNT162b2 as a primary course. The pooled adjusted hazard ratio (aHR) was 1.01 with a 95% confidence interval (CI) of: 0.90 to 1.13. After an mRNA booster dose, we found no difference in protection comparing those with a primary course of BNT162b2 with those with a ChAdOx1 primary course. This contrasts with pre-booster findings where previous research shows greater effectiveness of BNT162b2 than ChAdOx1 in preventing infection.

Ataxia Telangiectasia Mutated and MSH2 Control Blunt DNA End Joining in Ig Class Switch Recombination.

Class-switch recombination (CSR) produces secondary Ig isotypes and requires activation-induced cytidine deaminase (AID)-dependent DNA deamination of intronic switch regions within the IgH (Igh) gene locus. Noncanonical repair of deaminated DNA by mismatch repair (MMR) or base excision repair (BER) creates DNA breaks that permit recombination between distal switch regions. Ataxia telangiectasia mutated (ATM)-dependent phosphorylation of AID at serine 38 (pS38-AID) promotes its interaction with apurinic/apyrimidinic endonuclease 1 (APE1), a BER protein, suggesting that ATM regulates CSR through BER. However, pS38-AID may also function in MMR during CSR, although the mechanism remains unknown. To examine whether ATM modulates BER- and/or MMR-dependent CSR, Atm-/- mice were bred to mice deficient for the MMR gene mutS homolog 2 (Msh2). Surprisingly, the predicted Mendelian frequencies of Atm-/-Msh2-/- adult mice were not obtained. To generate ATM and MSH2-deficient B cells, Atm was conditionally deleted on an Msh2-/- background using a floxed ATM allele (Atmf) and B cell-specific Cre recombinase expression (CD23-cre) to produce a deleted ATM allele (AtmD). As compared with AtmD/D and Msh2-/- mice and B cells, AtmD/DMsh2-/- mice and B cells display a reduced CSR phenotype. Interestingly, Sμ-Sγ1 junctions from AtmD/DMsh2-/- B cells that were induced to switch to IgG1 in vitro showed a significant loss of blunt end joins and an increase in insertions as compared with wild-type, AtmD/D, or Msh2-/- B cells. These data indicate that the absence of both ATM and MSH2 blocks nonhomologous end joining, leading to inefficient CSR. We propose a model whereby ATM and MSH2 function cooperatively to regulate end joining during CSR through pS38-AID.

System design for 700 °C power plants: Integration scheme and performance evaluation

With the increase of steam parameters, how to improve the available energy proportion from high-temperature flue gas and realize efficient utilization of low-grade flue gas heat are two key issues that limit the efficiency improvement of power plants. In this study, a base scheme for the 700 °C single reheat power plant is proposed by the design of flue gas and steam regenerative systems for solving the above issues. However, large cold end loss in boiler and turbine and imperfect thermodynamic processes in flue gas and steam regenerative systems are bottlenecks for further improvement of energy efficiency. An integration scheme of flue gas and steam regenerative systems is proposed, and a comprehensive evaluation is performed from the perspectives of energy, exergy, CO2 emission reduction, and economy. The analysis results indicate that the net efficiency of the integration scheme reaches 50.3%. The exergy loss is reduced by 56.9 MW compared with the base scheme. The increased investment can be recovered within 4.7 years. In the design of the 700 °C power plant, special attention should be paid to perfecting the thermodynamic processes of its flue gas and steam regenerative systems.

Studying the Effect of the Tangential Nonuniformity of Flow Parameters on Gas Dynamic Performances of the Nozzle Cascades of Turbine Machines

Aerodynamic efficiency of the nozzle cascades of steam and gas turbines is defined by many factors and one of them is the tangential and radial nonuniformity degree of the parameters of a spatial flow behind the cascades. The averaging of these parameters enables the determination of the integral parameters of the cascades, in particular two flow angles and the velocity angle or the kinetic energy loss coefficient. The angle that takes into account the level of the averaged radial component of the velocity defines the level of kinematic losses in the cascade. Even in the case of the cylindric boundaries of the cascade this angle differs from zero and kinematic losses decrease the cascade efficiency by 30 to 50 percent. This scientific paper gives the results of experimental investigations of the effect of the circumferential nonuniformity of the velocity and the angles of the spatial flow on kinematic losses at different radii of the nozzle cascade of the last stage of the steam turbine and the nozzle cascade of the first stage of the gas turbine. The kinetic energy loss coefficient and the coefficient of total losses were suggested as the integral characteristics of the cascades. In the case of cylindric boundaries of the stage the total loss-to-kinetic energy loss ratio is noticeably decreased during the transition from the average zone to the zone of end losses. However, in the peripheral zone of the nozzle cascade of the last stage of steam turbine total losses are three times higher than kinetic energy losses due to the fact that the radial component of the velocity behind the cascade is much higher than the flow rate component and the level of the losses of kinetic energy is not high.

Analytic optical evaluation of linear aplanatic solar Fresnel reflectors

Linear Aplanatic Fresnel Reflectors (LAFRs) were recently presented as a novel and viable dual-mirror solar concentrator. Within a vast parameter space, a few promising designs were identified and evaluated via raytracing. This cumbersome, time-intensive exploration left unresolved whether configurations with superior optical performance remained undiscovered. Here, we present analytic methods for all inherent optical losses for the LAFR - results that are equally valid for almost all sources of optical loss in all linear Fresnel reflector solar concentrators. The loss modes include the separate contributions linked to the transverse and longitudinal projected incidence angles. This permits exact rapid comparisons among the wide range of possible aplanatic designs in a physically transparent manner that quantifies each mode of optical loss. These analytic derivations subsume blocking of rays reflected from the primary mirror segments, radiation that misses the primary and strikes the ground, shading of the primary by the secondary, end losses, and rays reflected from the primary that either miss the secondary (spillage) or enter it and miss the absorber tube (ray rejection). LAFR designs superior to those determined previously, in terms of higher intercept factor and higher concentration, are found and evaluated.

Bayesian and Non-Bayesian Inference for Weibull Inverted Exponential Model under Progressive First-Failure Censoring Data

In this article, the estimation of the parameters and the reliability and hazard functions for Weibull inverted exponential (WIE) distribution is considered based on progressive first-failure censoring (PFFC) data. For non-Bayesian inference, maximum likelihood (ML) estimators are acquired; meanwhile, their existence is verified. Via asymptotic normality of ML estimators and delta method, the corresponding confidence intervals (CIs) of the parameters and the reliability and hazard functions are constructed. For Bayesian inference, Lindley’s approximation and Markov chain Monte Carlo (MCMC) techniques are proposed to obain the Bayes estimators and the corresponding credible intervals (CRIs). To this end, both symmetric and asymmetric loss functions are used. A large number of Monte Carlo simulations are implemented to evaluate the efficiency of the developed methods. Eventually, a numerical example is analyzed for illustrative purposes.