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排序方式: 共有155条查询结果,搜索用时 31 毫秒
71.
Sanaz Jarolmasjed Carlos Zúñiga Espinoza Sindhuja Sankaran 《Sensing and Instrumentation for Food Quality and Safety》2017,11(3):987-993
Bitter pit is a physiological disorder in apples. Several major apple varieties are susceptible to this disorder that poses a great challenge to growers and the associated industry as it significantly reduces the produce utilization value and marketability. The current method of bitter pit detection is through visual assessment of symptoms. Near infrared (NIR) spectroscopy is a non-invasive technique that can be utilized towards detecting bitter pit development in fruits in pre-/non-symptomatic stages. Therefore, NIR spectra (935–2500 nm) of apples were collected from healthy and bitter pit Honeycrisp, Golden Delicious, and Granny Smith apples from a commercial orchard. The apples were stored in a controlled environment and spectral reflectance data were acquired at days 0, 7, 14, 35, and 63 after harvest. Chemical analysis was performed at the end of the storage period to estimate calcium, magnesium, and potassium content in the fruit peel. Partial least square regression (PLSR) was used to identify the apples as healthy or bitter pit using NIR-based spectral features. In addition, specific spectral features were selected by implementing two feature extraction methods: PLSR and stepwise discriminant analysis (SDA) on day 63 spectral dataset. The PLSR and SDA-based selected features from day 63 in Honeycrisp apples classified the same dataset with classification accuracies of about 100% with both methods. Regression analysis indicated a strong relationship between the PLSR-based spectral features and magnesium-to-calcium ratio in fruit peel in all three (Honeycrisp, Golden Delicious, and Granny Smith) apple varieties. 相似文献
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Ignacio de la Nuez Pestana Francisco Javier García Latorre Celso Argudo Espinoza Antonio Gmez Gotor 《Desalination》2004,160(3):293-299
Operation of an experimental RO plant connected directly to a wind system without energy storage was studied. The data obtained confirm the wide spectrum of operation of the plant with respect to the power available and the operation of the system. 相似文献
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Genetic algorithms allow solution of more complex, nonlinear civil, and environmental engineering problems than traditional gradient-based approaches, but they are more computationally intensive. One way to improve algorithm performance is through inclusion of local search, creating a hybrid genetic algorithm (HGA). The inclusion of local search helps to speed up the solution process and to make the solution technique more robust. This paper focuses on the effects of different local search algorithms on the performance of two different HGAs developed in previous phases of this research, the self-adaptive hybrid genetic algorithm (SAHGA) and the enhanced SAHGA. The algorithms are tested on eight test functions from the genetic and evolutionary computation literature and a groundwater remediation design case study. The results show that the selection of the local search algorithm to be combined with the simple genetic algorithm is critical to algorithm performance. The best local search algorithm varies for different problems, but can be selected prior to solving the problem by examining the reduction in fitness standard deviation associated with each local search algorithm, and the time distribution associated to the local search algorithm. 相似文献
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A high-performance single-stage UPS system for single-phase AC power supply systems is presented. The topology generates a trapezoidal-shaped load voltage that is synchronized with the AC supply; therefore, a small DC-link capacitor is required. This feature leads to a high-input power factor (0.94 at nominal voltage), and due to the single-stage structure, high efficiency (93% at nominal voltage) is also achieved. Moreover, in both cases the supply current spectrum presents low-order harmonics, all of which satisfy IEC 555. The high performance is validated using both resistive (linear) and diode RC (nonlinear) loads. The dynamic performance of the UPS system is also analyzed under different transient conditions. Specifically, the supply to battery, battery to supply transition, load transient, and supply/battery-voltage transients are performed. They show a transfer time of 500 μs (from AC supply to battery) and overvoltages of at most 15%. The dynamic and static evaluations are performed on a 1 kVA UPS system. The design guidelines for the key components and control parameters are also included 相似文献
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R Espinoza P Vial LM Noriega A Johnson ST Nichol PE Rollin R Wells S Zaki E Reynolds TG Ksiazek 《Canadian Metallurgical Quarterly》1998,4(1):93-95
The cost, side effect profile, and required weekly blood draws associated with clozapine may dissuade some clinicians from prescribing this atypical neuroleptic to mentally retarded patients. All publications on clozapine use in mentally retarded patients are reviewed and the treatment of 10 such patients is described, bringing the total number of published cases to 84. Clozapine is efficacious and well tolerated in this population and should be considered for those patients with psychosis or bipolar illness who are intolerant of or unresponsive to other agents. 相似文献
79.
Nanomechanical properties and thermal stability of recycled cellulose reinforced starch–gelatin polymer composite 下载免费PDF全文
Wendy Rodríguez‐Castellanos Francisco Javier Flores‐Ruiz Fernando Martínez‐Bustos Fernando Chiñas‐Castillo Francisco Javier Espinoza‐Beltrán 《应用聚合物科学杂志》2015,132(14)
Samples of starch?gelatin polymer reinforced with 5% of recycled cellulose were prepared using an extrusion‐compression molding process. Nanoindentation and atomic force acoustic microscopy (AFAM) techniques were used to study the effect of reinforcement at nanoscale level. Nanoindentation tests show a 163% increase in hardness and 123% of elastic modulus enhancement after recycled cellulose inclusion. AFAM shows that distribution of recycled cellulose into the polymer matrix is rather homogeneous at nanoscale which improves load transfer. Thermogravimetric analysis indicates an increase in thermal stability of the cellulose reinforced polymer matrix samples. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41787. 相似文献
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P Martínez-Osuna JB Zwolinska DH Sikes JG Cory LH Silveira LJ Jara LR Espinoza 《Canadian Metallurgical Quarterly》1993,11(3):249-253
Whether methotrexate (MTX) is effective in rheumatoid arthritis (RA) because of immunosuppressive and/or anti-inflammatory mechanisms of action is controversial. Many lines of investigation point to the latter. We evaluated DNA synthesis in peripheral blood lymphocytes (PBL) from 33 RA patients on oral MTX (7.5-15 mg/wk) and in 30 healthy controls by flow cytometric cell cycle analysis (CCA). DNA synthesis was also evaluated with a thymidilate synthetase activity assay (TSA) (3H-deoxyuridine incorporation) in 12 patients and 21 controls (12 on MTX and NSAID, and 9 healthy subjects). The patients had taken MTX for at least 3 months and were in different stages of clinical activity. There were no significant differences in TSA or in the cell cycle phase distributions (especially the S phase) between treated RA patients and controls. These data suggest that low-dose oral MTX does not inhibit DNA synthesis and therefore does not have an immunosuppressive effect on lymphocytes from patients with RA. 相似文献