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1.
The oxidation of low concentrations of hydrogen sulfide with air over activated carbon was studied over the temperature range 24-200°C using both fixed and fluid bed reactors. The predominant reaction, H2S + ½ Oa → H2O + S, was found to have an order of 0.5 with respect of H2S concentration. Activity of the catalyst decreased as the amount of sulfur deposited on it increased. Indirect evidence suggests that adsorption of water by the carbon also decreases its activity as a catalyst at lower temperatures. Values of the activation energy and the frequency factor were determined for various sulfur loadings using the fixed bed reaction system. Regeneration of the carbon loaded with sulfur was studied at temperatures between 150 and 500°C using steam as a carrier gas. Bright yellow sulfur was recovered. The regenerated carbon was shown to have its original activity. 相似文献
2.
Oznur Ozaltin Orhan Coskun Ozgur Yeniay Abdulhamit Subasi 《International journal of imaging systems and technology》2023,33(1):69-91
Classification of brain hemorrhage computed tomography (CT) images provides a better diagnostic implementation for emergency patients. Attentively, each brain CT image must be examined by doctors. This situation is time-consuming, exhausting, and sometimes leads to making errors. Hence, we aim to find the best algorithm owing to a requirement for automatic classification of CT images to detect brain hemorrhage. In this study, we developed OzNet hybrid algorithm, which is a novel convolution neural networks (CNN) algorithm. Although OzNet achieves high classification performance, we combine it with Neighborhood Component Analysis (NCA) and many classifiers: Artificial neural networks (ANN), Adaboost, Bagging, Decision Tree, K-Nearest Neighbor (K-NN), Linear Discriminant Analysis (LDA), Naïve Bayes and Support Vector Machines (SVM). In addition, Oznet is utilized for feature extraction, where 4096 features are extracted from the fully connected layer. These features are reduced to have significant and informative features with minimum loss by NCA. Eventually, we use these classifiers to classify these significant features. Finally, experimental results display that OzNet-NCA-ANN excellent classifier model and achieves 100% accuracy with created Dataset 2 from Brain Hemorrhage CT images. 相似文献
3.
Guillermo A. Oliveira Udry Laura Tiessler-Sala Eva Pugliese Agathe Urvoas Zakaria Halime Jean-Didier Marchal Jean-Pierre Mahy Rmy Ricoux 《International journal of molecular sciences》2022,23(23)
The covalent insertion of a cobalt heme into the cavity of an artificial protein named alpha Rep (αRep) leads to an artificial cobalt hemoprotein that is active as a catalyst not only for the photo-induced production of H2, but also for the reduction of CO2 in a neutral aqueous solution. This new artificial metalloenzyme has been purified and characterized by Matrix Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS), circular dichroism, and UltraViolet–Visible spectroscopy. Using theoretical experiments, the structure of this biohybrid and the positioning of the residues near the metal complex were examined, which made it possible to complete the coordination of the cobalt ion by an axial glutamine Gln283 ligand. While the Co(III)–porphyrin catalyst alone showed weak catalytic activity for both reactions, 10 times more H2 and four times more CO2 were produced when the Co(III)–porphyrin complex was buried in the hydrophobic cavity of the protein. This study thus provides a solid basis for further improvement of these biohybrids using well-designed modifications of the second and outer coordination sphere by site-directed mutagenesis of the host protein. 相似文献
4.
Identification and verification of a video clip via its fingerprint find applications in video browsing, database search and security. For this purpose, the video sequence must be collapsed into a short fingerprint using a robust hash function based on signal processing operations. We propose two robust hash algorithms for video based both on the discrete cosine transform (DCT), one on the classical basis set and the other on a novel randomized basis set (RBT). The robustness and randomness properties of the proposed hash functions are investigated in detail. It is found that these hash functions are resistant to signal processing and transmission impairments, and therefore can be instrumental in building database search, broadcast monitoring and watermarking applications for video. The DCT hash is more robust, but lacks security aspect, as it is easy to find different video clips with the same hash value. The RBT based hash, being secret key based, does not allow this and is more secure at the cost of a slight loss in the receiver operating curves 相似文献
5.
As demand for more power increases, compression ratios, and operating temperatures keep rising. High speeds combined with
high temperatures make turbomachinery sealing applications even more challenging. In order to confirm sufficient service life
material pairs should be tested under conditions similar to engine operating conditions. This study presents high temperature
friction and wear characteristics of cobalt/nickel superalloys, Haynes 25 (51Co–10Ni–20Cr–15W), Haynes 188 (39Co–22Ni–22Cr–14W),
and Haynes 214 (75Ni–16Cr–3Fe–0.5Mn) sheets when rubbed against Hastelloy X (47Ni–22Cr–18Fe–9Mo) pins. Tests are conducted
at 25, 200, 400, and 540 °C with a validated custom design linear reciprocating tribometer. Sliding speed and sliding distance
are 1 Hz and 1.2 km, respectively. Friction coefficients are calculated with friction force data acquired from a load cell.
Wear coefficients are calculated through weight loss measurements. Results indicate that Haynes 25 (H25) has the lowest friction
coefficients at all test temperatures. Above 400 °C, H25 and Haynes 188 (H188) exhibit the best wear resistance. Protective
cobalt oxide layers are formed on the H25 and H188 at 540 °C in addition to nickel, chrome, and tungsten oxides. Although,
it has better oxidation resistance, Haynes 214 has relatively higher wear rates than other tested materials especially at
low temperatures. However, its wear performance improves beyond 200 °C. 相似文献
6.
Healthcare facilities are often complex and overwhelming for visitors, and wayfinding in healthcare facilities can be challenging. As there is an increasing number of global citizens who travel to seek medical care in another country, it is critical to make wayfinding easy for visitors who are not familiar with the language in a foreign country. Among many wayfinding aids, symbols are helpful for those visitors who have limited ability to understand written language. This study tested universal healthcare symbols in the United States, South Korea, and Turkey to compare the comprehension of symbols cross-country and identify predictors of the correct comprehension. To explore statistically significant relationships between symbol comprehension and countries, Pearson's Chi-square tests, logistic regression, and ANOVA were conducted. The test results showed that ten symbols among 14 tested have significant relationship with countries. Results of this study demonstrate that symbol comprehension can be varied significantly in different countries. 相似文献
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9.
Gokhan Aydin Izzet Karakurt Coskun Hamzacebi 《The International Journal of Advanced Manufacturing Technology》2014,75(9-12):1321-1330
An experimental study is carried out for modeling the rock cutting performance of abrasive waterjet. Kerf angle (KA) is considered as a performance criteria and modeled using artificial neural network (ANN) and regression analysis based on operating variables. Three operating variables, including traverse speed, standoff distance, and abrasive mass flow rate, are studied for obtaining different results for the KA. Data belonging to the trials are used for construction of ANN and regression models. The developed models are then tested using a test data set which is not utilized during construction of models. Additionally, the regression model is validated using various statistical approaches. The results of regression analysis are also used to determine the significant operating variables affecting the KA. Furthermore, the performances of derived models are compared for showing the accuracy levels in prediction of the KA. As a result, it is concluded that both ANN and regression models can give adequate prediction for the KA with an acceptable accuracy level. The compared results reveal also that the corresponding ANN model is more reliable than the regression model. On the other hand, the standoff distance and traverse speed are statistically determined as dominant operating variables on the KA, respectively. 相似文献
10.
M.I. Karamangil S. Coskun O. Kaynakli N. Yamankaradeniz 《Renewable & Sustainable Energy Reviews》2010,14(7):1969-1978
This study presents a literature review, especially in recent years, on the absorption refrigeration systems (ARSs), the currently used refrigerant–absorbent pairs and their alternatives. Additionally, in this study, the thermodynamic analysis of ARS using commonly encountered solution pairs in the literature was carried out, and a user-friendly software package including visual components was developed. The effects of operating temperatures, the effectivenesses of solution, refrigerant and solution–refrigerant heat exchangers (SHE, RHE, SRHE), and selection of working fluid pair on the system performance were examined by using the developed package. It was concluded that performances of the cycles improve with increasing generator and evaporator temperatures, but reduce with increasing condenser and absorber temperatures. The performance of system was affected from the SHE more than the RHE and SRHE. While the use of SHE improves the system COP up to 66%, RHE and SRHE have an effect of only 14% and 6%, respectively. For that reason, the SRHE may not be considered practically significant. Suitable solutions depending on operating conditions showed variations with respect to generator and evaporator temperatures. 相似文献