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91.
92.
M. M. Faruque Hasan I. A. Karimi H. E. Alfadala H. Grootjans 《American Institute of Chemical Engineers》2009,55(1):150-171
Multistream heat exchangers (MSHE) enable the simultaneous exchange of heat among multiple streams, and are preferred in cryogenic processes such as air separation and LNG. Most MSHEs are complex; proprietary and involve phase changes of mixtures. Although modeling MSHE is crucial for process optimization, no such work exists to our knowledge. We present a novel approach for deriving an approximate operational (vs. design) model from historic data for an MSHE. Using a superstructure of simple 2‐stream exchangers, we propose a mixed‐integer nonlinear programming (MINLP) formulation to obtain a HE network that best represents the MSHE operation. We also develop an iterative algorithm to solve the large and nonconvex MINLP model in reasonable time, as existing commercial solvers fail to do so. Finally, we demonstrate the application of our work on an MSHE from an existing LNG plant, and successfully predict its performance over a variety of seasons and feed conditions. © 2008 American Institute of Chemical Engineers AIChE J, 2009 相似文献
93.
Prediction of Egg Freshness and Albumen Quality Using Visible/Near Infrared Spectroscopy 总被引:1,自引:0,他引:1
Nicolas Abdel-Nour Michael Ngadi Shiv Prasher Yousef Karimi 《Food and Bioprocess Technology》2011,4(5):731-736
Important changes occur in egg during storage leading to loss of quality. Prediction of these changes is critical in order
to monitor egg quality and freshness. The aim of this research was to evaluate application of visible (VIS) and near infrared
(NIR) spectroscopy as a rapid and non-destructive technique for egg quality assessment. Three hundred and sixty intact white-shelled
eggs freshly laid by the same flock of hens fed with a standard feed were obtained. They were put under controlled conditions
of temperature and humidity (T = 18 °C and RH = 55%) for 16 days of storage. Forty eggs were analyzed at day 0, 2, 4, 6, 8, 10, 12, 14, and 16. Transmission
spectral data was obtained in the range from 350 to 2,500 nm. The non-destructive spectral data was compared to egg sample’s
Haugh unit (HU) and albumen pH in terms of quality and to the number of storage days in terms of freshness. A partial least
squares predictive model was developed and used to link the destructive assessment methods and the number of storage days
with the spectral data. The correlation coefficient between the measured and predicted values of HU, albumen pH, and number
of storage days were up to 0.94, R
2 was up to 0.90 and the root mean square error values for the validation were 5.05, 0.06, and 1.65, respectively. These results
showed that VIS/NIR transmission spectroscopy is a good tool for assessment of egg freshness and albumen pH and can be used
as a non-destructive method for the prediction of HU, albumen pH, and number of storage days. In addition, the relevant information
about these parameters was in the VIS and NIR ranging from 411 to 1,729 nm. 相似文献
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96.
Zahra Safaei Keikhosro Karimi Poorandokht Golkar Akram Zamani 《International journal of molecular sciences》2015,16(7):16683-16694
The objective of this study was to investigate the effects of indole-3-acetic acid (IAA) and kinetin (KIN) on Mucor indicus growth, cell wall composition, and ethanol production. A semi-synthetic medium, supplemented with 0–5 mg/L hormones, was used for the cultivations (at 32 °C for 48 h). By addition of 1 mg/L of each hormone, the biomass and ethanol yields were increased and decreased, respectively. At higher levels, however, an inverse trend was observed. The glucosamine fraction of the cell wall, as a representative for chitosan, followed similar but sharper changes, compared to the biomass. The highest level was 221% higher than that obtained without hormones. The sum of glucosamine and N-acetyl glucosamine (chitin and chitosan) was noticeably enhanced in the presence of the hormones. Increase of chitosan was accompanied by a decrease in the phosphate content, with the lowest phosphate (0.01 g/g cell wall) being obtained when the chitosan was at the maximum (0.45 g/g cell wall). In conclusion, IAA and KIN significantly enhanced the M. indicus growth and chitosan production, while at the same time decreasing the ethanol yield to some extent. This study shows that plant growth hormones have a high potential for the improvement of fungal chitosan production by M. indicus. 相似文献
97.
The Journal of Supercomputing - According to the recent advancements in communication technologies and the widespread use of smart devices, our environment can be transforming into the Internet of... 相似文献
98.
Ross Sparks Brian Jin Sarvnaz Karimi Cecile Paris C. R. MacIntyre 《Quality Engineering》2019,31(1):73-90
AbstractThis article focuses on monitor plans aimed at the early detection of the increase in the frequency of events. The literature recommends either monitoring the time between events (TBE) if events are rare or counting the number of events per unit non-overlapping time intervals otherwise. Some authors advocate using the Bernoulli model for rare events, applying presence or absence of events within non-overlapping and exhaustive time intervals. This Bernoulli model does improve the real-time monitoring assessment of these events compared to counting events over a larger interval, making them less rare. However this approach became inefficient if more than one event starts occurring within the intervals. Monitoring TBE is the real-time option for outbreak detection, because outbreak information is accumulated when an event occurs. This is preferred to waiting for the end of a period to count events. If the TBE reduces significantly, then the incidence of these events increases significantly. This article explores this TBE option relative to using the monitoring of counts when the TBEs are either Exponentially, Gamma or Weibull distributed for moderately low count scenarios. The article will discuss and compare the approaches of using an Exponentially Weighted Moving Average (EWMA) statistic for the TBEs to the EWMA of counts. Several robust options will be considered when the future change in event frequency is unknown. Our goal is to have a robust monitoring plan which is able to efficiently detect many different levels of shifts. These robust plans are compared to the more traditional event monitoring plans for both small and large changes in the event frequency. 相似文献
99.
Aida Karimi Seyed Hesam Mirfarsi Soosan Rowshanzamir Fatemeh Beyraghi Daniel Lester 《国际能源研究杂志》2020,44(11):8877-8891
Weak phase separation and vulnerable linking groups between aromatic units are common setbacks of sulfonated aromatic proton exchange membranes (PEMs) from durability point of view. In this study, sulfonated poly(ether ether ketone) (SPEEK) membranes were exposed to Fenton's solution for a specific time, ranging from 10 to 60 minutes. Chemical structure and morphology evolution, decay in mechanical and thermal stability, and H2 permeability of SPEEK membranes were evaluated during the chemical degradation. Less-entangled polymeric chains with lower average molecular weight of degraded SPEEK samples diminished mechanical rigidity. In addition, reduction of aromatic rings in each repeat unit led to higher thermal decomposition rate. Furthermore, randomly distributed micro-defects in the SPEEK morphology and an increase in water sorption can reduce the fatigue strength of membranes in the wet-dry cycles. Eventually, hydrogen cross-over rate was gradually increased, and henceforth, accelerated destructive radical formation and degradation can be predicted. 相似文献
100.
Ayat Mehdi Kamali Abdoljabbar Mirzakuchaki Sattar 《Wireless Personal Communications》2019,108(2):1243-1259
Wireless Personal Communications - In this paper, a robust carrier recovery loop for high dynamic and weak signals in GPS receivers is proposed. To achieve optimal tracking performance at... 相似文献