Comparison of catalytic and noncatalytic pyrolysis and product yields of some waste biomass species

The products obtained by fast pyrolysis of biomass can be used as an energy source or chemical raw material. In this study, samples of hazelnut shells, tea bush, and hazelnut knot selected as waste biomass were from the cities of Trabzon and Rize in the Eastern Black Sea Region. Firstly, the waste biomass samples were granulated into four different particle sizes by milling and sieving operations. Fast pyrolysis of the samples with specific mixing rates was carried out in a fixed bed reactor. Additionally, 2 wt% vanadium (V) oxide (V₂O₅) was used as catalyst to maximize the yield of pyrolysis liquid products. The influence of temperature, heating rate, and particle size on fast pyrolysis yields under both catalytic and noncatalytic conditions were investigated and compared. While the amount of liquid product increased with the addition of catalyst, the amount of solid products decreased. It has been found that the temperature and heating rate parameters are very effective in liquid product yield. In all experiments, the maximum liquid yield was acquired at the same heating rate of 450°C min^?1 and the temperature of 450°C with particle size of 0.5 to 1.0 mm. The maximum pyrolysis liquid (bio‐oil) was obtained with catalytic pyrolysis, and this value was 60.58 wt%.     

Time and volume-ratio effect on reusable polybenzoxazole nanofiber oil sorption capacity investigated via machine learning

Diesel oil sorption capacities (DOSCs) of polybenzoxazole/polyvinylidene fluoride nanofiber mats with four different groups (-O-, -S-S-, phenylene and diphenylene) in the main chain structures were investigated. Different experimental duration and diesel-oil/tap-water volume ratio pairs were used for diesel oil sorption. No degradation was observed in the nanofiber mat structures after diesel oil sorption. The characterizations of polybenzoxazole (PBO) nanofibers with high diesel oil selectivity were performed by scanning electron microscopy, atomic force microscopy, Fourier transform infrared spectroscopy, x-ray diffraction, thermal gravimetric analysis, differential scanning calorimetry, Brunauer–Emmett–Teller (BET), and contact angle measurement analysis. According to the result of characterizations, superoleophilic and superhydrophobic nanofiber mats show high water contact angle value in the range of 132–140^∘ and show high separation efficiency. In this study, we integrated ensemble gradient boosting model (XGBoost) to predict the DOSC of sorbent nanofiber and obtain an optimal set of conditions to maximize the DOSC. The predicted PBO-E sorbent at the 0.5 ratio of diesel-oil/tap-water measured at the end of the 3rd minute showed the most reliable and stable diesel oil sorption with at least 9.39 and at most 12.33 g/g sorbent with 95% of confidence.     

Cache recovery and spatial memory in Clark's nutcrackers (Nucifraga columbiana).

Clark's nutcrackers cache pine seeds and recover them months later. Four experiments with 5 nutcrackers tested their ability to relocate their caches when the cache sites were selected by the experimenters. During Exp I, Ss had 18 cache sites available during each of 3 caching sessions, followed 10 days later by 4 recovery sessions. Recovery performance was above chance, and there were frequent revisits to previously emptied cache sites. During Exp II, hunger level (manipulated by prefeeding) had no effect on recovery accuracy. During Exp III, Ss were released into the experimental room with no seeds present. Probing behavior was directed at the old cache sites of Exp I and especially of Exp II. During Exp IV, the number of holes available during caching sessions had no effect on the accuracy of 3 of the 4 Ss. Findings suggest that spatial memory is a primary mechanism by which nutcrackers locate their caches. (30 ref) (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Performance of four-seed caching corvid species in operant tests of nonspatial and spatial memory.

The performance of 4 seed-caching corvid species was tested using 2 different operant nonmatching tasks. These species differ in their dependence on stored food, and differences in spatial memory tests have been correlated with better performance by the more cache-dependent species. Acquisition and retention of a color non-matching-to-sample task was tested in Experiment 1. Acquisition of the color task was not correlated with cache dependence, and no differences between species in performance during memory testing were found. Acquisition and retention of an operant spatial non-matching-to-sample task was tested in Experiment 2. Species differences in the spatial task were found for acquisition and during retention testing. The influence of natural history on the evolution of memory is discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Magnetic sensor with prism coupler

The physical principle of proposed sensor is based on the combination of two effects: the modulation of permittivity tensor elements in materials with induced anisotropy by external magnetic field and the creation of sharp minima in reflectance on prism base at guided mode resonance. As result we can observe pointed up the polarization states of reflected light beam influenced by external magnetic field.

Procedures based on the Yeh’s 4×4 matrix formalism are described for the treatment of the electromagnetic interactions in prism-layered or -bulk structure with magnetic ordering. The tunneling phenomenon between coupling prism and inspected object is analyzed for ultrathin approximation and for the case of a gap spacing wide enough so that the prism could be considered as weak perturbation to the modes of the free structure. The value of Kerr rotation at resonant states achieves to one radian. Its dependence on in-plane modulation of magnetization direction offers the possibility to realize the magnetic vector sensor with angle distinguishing better than one degree.     

Selective oxidation of methane with air over silica catalysts

Partial oxidation of methane by oxygen to form formaldehyde, carbon oxides, and C₂ products (ethane and ethene) has been studied over silica catalyst supports (fumed Cabosil and Grace 636 silica gel) in the 630–780 °C temperature range under ambient pressure. The silica catalysts exhibit high space time yields (at low conversions) for methane partial oxidation to formaldehyde, and the C₂ hydrocarbons were found to be parallel products with formaldehyde. Short residence times enhanced both the C₂ hydrocarbons and formaldehyde selectivities over the carbon oxides even within the differential reactor regime at 780 °C. This suggests that the formaldehyde did not originate from methyl radicals, but rather from methoxy complexes formed upon the direct chemisorption of methane at the silica surface at high temperature. Very high formaldehyde space time yields (e.g., 812 g/kg cat h at the gas hourly space velocity = 560 000 (NTP)/kg cat h) could be obtained over the silica gel catalyst at 780 °C with a methane/air mixture of 1.5/1. These yields greatly surpass those reported for silicas earlier, as well as those over many other catalysts. Low CO₂ yields were observed under these reaction conditions, and the selectivities to formaldehyde and C₂ hydrocarbons were 28.0 and 38.8%, respectively, at a methane conversion of 0.7%. A reaction mechanism was proposed for the methane activation over the silica surface based on the present studies, which can explain the product distribution patterns (specifically the parallel formation of formaldehyde and C₂ hydrocarbons).     

Experimental Determination of the Length-Scale Parameter for the Phase-Field Modeling of Macroscale Fracture in Cr–Al2O3 Composites Fabricated by Powder Metallurgy

Metallurgical and Materials Transactions A - A novel approach is proposed to determine a physically meaningful length-scale parameter for the phase-field modeling of macroscale fracture in...     

Automatic prostate cancer detection model based on ensemble VGGNet feature generation and NCA feature selection using magnetic resonance images

Multimedia Tools and Applications - Prostate cancer is one of the most common types of cancer in men and its frequency is 28 per hundred thousand in the world. This cancer is detected using...     

Adaptable image segmentation via simple pixel classification

We propose an approach to image segmentation that views it as one of pixel classification using simple features defined over the local neighborhood. We use a support vector machine for pixel classification, making the approach automatically adaptable to a large number of image segmentation applications. Since our approach utilizes only local information for classification, both training and application of the image segmentor can be done on a distributed computing platform. This makes our approach scalable to larger images than the ones tested. This article describes the methodology in detail and tests it efficacy against 5 other comparable segmentation methods on 2 well‐known image segmentation databases. Hence, we present the results together with the analysis that support the following conclusions: (i) the approach is as effective, and often better than its studied competitors; (ii) the approach suffers from very little overfitting and hence generalizes well to unseen images; (iii) the trained image segmentation program can be run on a distributed computing environment, resulting in linear scalability characteristics. The overall message of this paper is that using a strong classifier with simple pixel‐centered features gives as good or better segmentation results than some sophisticated competitors and does so in a computationally scalable fashion.