Performance optimization of an air-standard irreversible dual-atkinson cycle engine based on the ecological coefficient of performance criterion.
Ontology highlight
ABSTRACT:
SUBMITTER: Gonca G
PROVIDER: S-EPMC4138611 | biostudies-other | 2014
REPOSITORIES: biostudies-other
Similar Datasets
Project description: Not available
| S-EPMC7655303 | biostudies-literature
Project description:In current research, the hydraulic performance prediction and optimization of an engine cooling water pump was conducted by computational fluid dynamic (CFD) analysis. Through CFD simulation, the pump head, shaft power and efficiency for the original pump at volume flow rate 25 L/min and impeller rotating speed 4231 r/min were 3.87 m, 66.7 W and 23.09% respectively. For improving hydraulic performance, an optimization study was carried out. After optimization, four potential optimized designs were put forward. The efficiency of the optimized design No.1 for engine cooling water pump was nearly 6% higher than that of the original pump model; and the head of the optimized design No.2 for engine cooling water pump was 9% higher than that of the original pump model. Under the condition of maintaining the pump head and considering comprehensive improvement effect, the optimized design No.3 was considered as the best design and selected as the test case for validating the optimum design. The hydraulic performance predictions for this optimum engine cooling water pump agreed well with experimental data at design condition with relative discrepancies of 2.9% and 5.5% for the pump head and pump efficiency, respectively. It proved that performance prediction calculation model and the automatic optimization model were effective. This research work can provide theoretical basis for the design, development and optimization of engine cooling water pump.
| S-EPMC8205170 | biostudies-literature
Project description:This research focuses on developing an improved and robust measurement for emergency department (ED) performance and a criterion standard for global use via kinetic analysis. Based on kinetic approach, the input-throughput-output conceptual model of ED crowding is compared to the procedure of enzyme catalysis. All in average, the retented patients in EDs are defined as substrate (S), whereas the patients who depart the EDs as product (P). Therefore, the average ED departure velocity (V) can be presented as (P)divided by a given time (t) of the ED length of stay (LOS). The S-V and S²-P plots are depicted hourly for the kinetic analysis. The long-term stability of the kinetic parameters is ascertained by the method of coefficient of variation (CV). The participants collected for this study are from the EDs of Changhua Christian Medical Center and the five branched hospitals, all located in Taiwan. Based on the S-V plot analysis, the results clearly show 2 curves, an upper and a lower curve. The timeline of the lower curve includes approximately the total ED busy hours, and thus it can be used for the subsequent kinetic analysis. In order to explore the adequate kinetic parameters for ED performance, the try-and-error process was followed in this study. As a result, the S²-V plots adapted from the lower curves show the best linear regression of S² on V with a good coefficient of determination (R). The Pan-Wen constant (PW), which is the slope of the liner regression line, and the ED medical personnel unit turnover number (EDMPU TON) were deduced from the kinetic meanings of (Equation is included in full-text article.)plots. In this research, the 2 kinetic parameters, PW and EDMPU TON were applied for the ED performance evaluations. An innovative relationship between the ED retented patients and the ED departure velocity is verified as PW; whereas, a feasible kinetic parameter, the EDMPU TON explicates the teamwork efficiency of the ED providers. Moreover, the EDMPU TON may not only be a reliable universal criterion standard for the ED performance, but also a valuable reference for both ED providers and payers.
| S-EPMC4839888 | biostudies-other
Project description:SIGNIFICANCE:Uncorrected refractive error is a prevalent problem throughout the world especially among the low-income population who have limited access to professional eye care and cannot afford eyeglasses. PURPOSE:The purpose of this study was to evaluate the accuracy and usability of a low-cost, portable, smartphone-based autorefractor (Netra, EyeNetra Inc., Somerville, MA) in adults. METHODS:A cross-sectional study was conducted to compare the portable refractor with subjective (manifest and cycloplegic) refraction for sequential adult participants with best-corrected visual acuity of 20/40 or greater. For each method of refraction, the spherical equivalent was calculated. Differences between methods were tested with linear mixed regression models. A validated usability questionnaire was administered regarding ease of use (100-point scale, higher scores better) for the portable autorefractor. RESULTS:Eighty-seven subjects (152 eyes) were studied (age range, 20 to 90 years; mean ± standard deviation, 51.9 ± 18.3 years). Mean spherical equivalent by the portable device was -2.76 D (range, -14.75 to 3.63 D) compared with -2.49 D (range, -15.25 to 4.25 D) by manifest refraction. The mean relative difference in spherical equivalent between methods was -0.27 D (P = .001, significantly different than 0 D). The mean absolute difference between methods was 0.69 D (P < .001, significantly different than 0.5-D absolute difference). Similar results were found when comparing spherical equivalent between Netra and cycloplegic refraction methods. Subjects reported average ease of use for the Netra of 75.4 ± 19.8. CONCLUSIONS:The portable autorefractor had small but clinically significant differences from subjective refraction. The device's scores on the usability scale indicate good overall patient acceptance. The device may be valuable for use where there is limited access to a trained refractionist.
| S-EPMC6475906 | biostudies-literature
Project description:In this paper, we report data and experiments related to the research article entitled "An adaptive truncation criterion, for linesearch-based truncated Newton methods in large scale nonconvex optimization" by Caliciotti et al. [1]. In particular, in Caliciotti et al. [1], large scale unconstrained optimization problems are considered by applying linesearch-based truncated Newton methods. In this framework, a key point is the reduction of the number of inner iterations needed, at each outer iteration, to approximately solving the Newton equation. A novel adaptive truncation criterion is introduced in Caliciotti et al. [1] to this aim. Here, we report the details concerning numerical experiences over a commonly used test set, namely CUTEst (Gould et al., 2015) [2]. Moreover, comparisons are reported in terms of performance profiles (Dolan and Moré, 2002) [3], adopting different parameters settings. Finally, our linesearch-based scheme is compared with a renowned trust region method, namely TRON (Lin and Moré, 1999) [4].
| S-EPMC5790812 | biostudies-other
Project description:BackgroundIrreversible electroporation (IRE) is a non-thermal cell ablation approach that induces selective damage to cell membranes only. The purpose of the current study was to evaluate and optimize its use for in-vivo myocardial decellularization.MethodsForty-two Sprague-Dawley rats were used to compare myocardial damage of seven different IRE protocols with anterior myocardial infarction damage. An in-vivo open thoracotomy model was used, with two-needle electrodes in the anterior ventricular wall. IRE protocols included different combinations of pulse lengths (70 vs. 100 ?seconds), frequency (1, 2, 4 Hz), and number (10 vs. 20 pulses), as well as voltage intensity (50, 250 and 500 Volts). All animals underwent baseline echocardiographic evaluation. Degree of myocardial ablation was determined using repeated echocardiography measurements (days 7 and 28) as well as histologic and morphometric analysis at 28 days.ResultsAll animals survived 28 days of follow-up. Compared with 50V and 250V, electroporation with 500V was associated with significantly increased myocardial scar and reduction in ejection fraction (67.4%±4% at baseline vs. 34.6%±20% at 28 days; p <0.01). Also, compared with pulse duration of 70 ?sec, pulses of 100 ?sec were associated with markedly reduced left ventricular function and markedly increased relative scar area ratio (28%±9% vs. 16%±3%, p = 0.02). Decreasing electroporation pulse frequency (1Hz vs. 2Hz, 2Hz vs. 4Hz) was associated with a significant increase in myocardial damage. Electroporation protocols with a greater number of pulses (20 vs. 10) correlated with more profound tissue damage (p<0.05). When compared with myocardial infarction damage, electroporation demonstrated a considerable likeness regarding the extent of the inflammatory process, but with relatively higher levels of extra-cellular preservation.ConclusionsIRE has a graded effect on the myocardium. The extent of ablation can be controlled by changing pulse length, frequency and number, as well as by changing electric field intensity.
| S-EPMC5125564 | biostudies-literature
Project description:Inhibitors of the human enzyme dimethylarginine dimethylaminohydrolase-1 (DDAH1) can control endogenous nitric oxide production. A time-dependent covalent inactivator of DDAH1, N5-(1-imino-2-chloroethyl)-l-ornithine ( KI = 1.3 ?M, kinact = 0.34 min-1), was conceptually dissected into two fragments and each characterized separately: l-norvaline ( Ki = 470 ?M) and 2-chloroacetamidine ( KI = 310 ?M, kinact = 4.0 min-1). This analysis suggested that the two fragments were not linked in a manner that allows either to reach full affinity or reactivity, prompting the synthesis and characterization of three analogues: two that mimic the dimethylation status of the substrate, N5-(1-imino-2-chloroisopropyl)-l-ornithine ( kinact /KI = 208 M-1 s-1) and N5-(1-imino-2-chlorisopropyl)-l-lysine ( kinact /KI = 440 M-1 s-1), and one that lengthens the linker beyond that found in the substrate, N5-(1-imino-2-chloroethyl)-l-lysine (Cl-NIL, KI = 0.19 ?M, kinact = 0.22 min-1). Cl-NIL is one of the most potent inhibitors reported for DDAH1, inactivates with a second order rate constant (1.9 × 104 M-1 s-1) larger than the catalytic efficiency of DDAH1 for its endogenous substrate (1.6 × 102 M-1 s-1), and has a partition ratio of 1 with a >100?000-fold selectivity for DDAH1 over arginase. An activity-based protein-profiling probe is used to show inhibition of DDAH1 within cultured HEK293T cells (IC50 = 10 ?M) with cytotoxicity appearing only at higher concentrations (ED50 = 118 ?M). A 1.91 Å resolution X-ray crystal structure reveals specific interactions made with DDAH1 upon covalent inactivation by Cl-NIL. Dissecting a covalent inactivator and analysis of its constituent fragments proved useful for the design and optimization of this potent and effective DDAH1 inhibitor.
| S-EPMC6074031 | biostudies-literature
Project description:Accurate information about the spatiotemporal variability of actual crop evapotranspiration (ETa), crop coefficient (Kc) and water productivity (WP) is crucial for water efficient management in the agriculture. The Earth Engine Evapotranspiration Flux (EEFlux) application has become a popular approach for providing spatiotemporal information on ETa and Kc worldwide. The aim of this study was to quantify the variability of water consumption (ETa) and the Kc for an irrigated commercial planting of soybeans based on the EEFlux application in the western region of the state of Bahia, Brazil. The water productivity (WP) for the fields was also obtained. Six cloud-free images from Landsat 7 and 8 satellites, acquired during the 2016/17 soybean growing season were used and processed on the EEFlux platform. The ETa from EEFlux was compared to that of the modified FAO (MFAO) approach using the following statistical metrics: Willmot's index of agreement (d-index), root mean square error (RMSE), mean absolute error (MAE) and mean bias error (MBE). The Kc from EEFlux was compared to the Kc used in the soybean field (Kc FAO-based) and to the Kc values obtained in different scientific studies using the d-index. A similar procedure was performed for WP. Our results reveal that EEFlux is able to provide accurate information about the variability of ETa and the Kc of soybean fields. The comparison between ETa EEFlux and ETa MFAO showed good agreement based on the d-index, with values of 0.85, 0.83 and 0.89 for central pivots 1, 2 and 3, respectively. However, EEFlux tends to slightly underestimate ETa. The Kc EEFlux showed good accordance with the Kc values considered in this study, except in phase II, where a larger difference was observed; the average WP of the three fields (1.14 kg m-3) was higher than that in the majority of the previous studies, which is a strong indicator of the efficient use of water in the studied soybean fields. The study showed that EEFlux, an innovative and free tool for access spatiotemporal variability of ETa and Kc at global scale is very efficient to estimate the ETa and Kc on different growth stages of soybean crop.
| S-EPMC7347170 | biostudies-literature
Project description:BackgroundMany structural bioinformatics approaches employ sequence profile-based threading techniques. To improve fold recognition rates, homology searching may include artificially evolved amino acid sequences, which were demonstrated to enhance the sensitivity of protein threading in targeting midnight zone templates.FindingsWe describe implementation details of eVolver, an optimization algorithm that evolves protein sequences to stabilize the respective structures by a variety of potentials, which are compatible with those commonly used in protein threading. In a case study focusing on LARG PDZ domain, we show that artificially evolved sequences have quite high capabilities to recognize the correct protein structures using standard sequence profile-based fold recognition.ConclusionsComputationally design protein sequences can be incorporated in existing sequence profile-based threading approaches to increase their sensitivity. They also provide a desired linkage between protein structure and function in in silico experiments that relate to e.g. the completeness of protein structure space, the origin of folds and protein universe. eVolver is freely available as a user-friendly webserver and a well-documented stand-alone software distribution at http://www.brylinski.org/evolver.
| S-EPMC3735418 | biostudies-literature
Project description:The introduction of new design solutions of cast components to the powertrain systems of passenger cars has resulted in an increased demand for optimization of mechanical properties obtained during heat treatment, assuring-at the same time-a suitable level of production capacity and limitation of manufacturing costs. In this paper, research results concerning non-standard T6 heat treatment of a combustion engine cylinder head made of AlSi7Cu3Mg alloy are presented. It has been confirmed that the optimal process of heat treatment of this component, taking into consideration the criterion of material hardness, involves solutioning at a temperature of 500 °C for 1 h, and then aging for 2 h at 175 °C. As a result, HBS10/1000/30 hardness in the range of 105-130 was obtained, which means an increase from 35% to 60% in comparison to the as-cast, depending on the position of the measurement and spheroidization of precipitations of eutectic silicon.
| S-EPMC7560336 | biostudies-literature