The microwave energy absorption behavior of the linear alkylbenzene sulfonate (LAS) surfactant detergent agglomerates was studied while considering changes in the physical properties of the samples. Microwave heating was used to change the internal structure of the agglomerates to make a reduced density (fluffy) product. The absorption of energy within LAS samples indicated fluctuating trends as microwave heating progressed. This was associated with the dielectric properties of the material which are strongly dependent upon the nature (“free” or “bound”) and quantity of water present in them at any instant which changes during heating. Therefore, complete profiles of the energy absorbed by the samples have been recorded to determine their actual power absorption behavior/total energy consumption over time. The bulk density of the agglomerates decreased significantly when exposed to microwave fields. Hot air drying can be combined with microwave heating to reduce the total heating time. It has been observed that the pre-heating of the samples reduces the total heating time and microwave energy requirement. This is due to the temperature-dependent decomposition of hydrates releasing more “free” water. 相似文献
The polyurethane pressure sensitive adhesive (PUPSA) films have been prepared on polypropylene sheets with coating bars. The topographical information of the dried films is investigated using phase images by using Atomic Force Microscope (AFM) in tapping mode. The film develops a segmental architecture by using different compositions. Various samples of PUPSA comprising of polypropylene glycol PPG (Mn?=?425, 1000, 2000 and 2700 g-mol?1) and hydroxyl terminated polybutadiene HTPB (Mn?=?1984 and 2912 g-mol?1) along with three different isocyanates: 1,6 hexane diisocyanate (HDI), isophorone diisocyanate (IPDI) and hexamethylene diisocyanate (H12MDI) have been used for capturing the images through AFM. The samples contained 40 wt.% of solid content containing different nature of macrodiols and diisocyanate. Due to varying composition, dispersion in domain area along with different contour and dimension has been observed in the images. Apparently, there seems no correlation of spherulites and lamellae in different domains. However, the properties imparted by high molecular weight HTPB resulted in non-adhesive stiff material.
Highly ordered mesoporous MCM-41 and SBA-15 have been synthesized and functionalized with different amounts of propyl sulfonic acid groups using 3-mercaptopropyltrimethoxysilane as sulfur source. The synthesized catalysts have been well-characterized by different techniques such as XRD, FTIR and BET surface area and pore size distribution by BJH method. FTIR spectra of chemisorbed pyridine and temperature programmed desorption of NH3 techniques have been successfully used to characterize the acidic sites. The results showed that, both surface area, mean pore diameter and pore volume decrease as the extent of sulfonation increase. XRD results and TEM images confirm the stability of mesoporous long range order even after sulfonation process done. In addition, the study also showed that, sulfonation enhances the surface acidity and new moderate and strong acid sites were created. All the sulfonated catalysts under investigations have been found to be highly active and selective for the Pechmann condensation reaction of resorcinol with ethyl acetoacetate. More than 98% yield of 7-hydroxy-4-methyl coumarin was obtained with 100% selectivity. Presence of high number of moderate and strong Brönsted acid sites in sulfonated catalysts help in achieving high yields. Furthermore, the MCM-41 sulfonated catalysts showed higher catalytic performance due to their higher surface acidities. 相似文献
Although there is no machine learning technique that fully meets human requirements, finding a quick and efficient translation mechanism has become an urgent necessity, due to the differences between the languages spoken in the world’s communities and the vast development that has occurred worldwide, as each technique demonstrates its own advantages and disadvantages. Thus, the purpose of this paper is to shed light on some of the techniques that employ machine translation available in literature, to encourage researchers to study these techniques. We discuss some of the linguistic characteristics of the Arabic language. Features of Arabic that are related to machine translation are discussed in detail, along with possible difficulties that they might present. This paper summarizes the major techniques used in machine translation from Arabic into English, and discusses their strengths and weaknesses. 相似文献
To examine the possible utilization of indigenous phosphate reserves, bench scale studies were under-taken to assess their suitability for phosphoric acid manufacture.It was found out that in spite of few problems, the Silicious phosphate reserves of 2–3 million tons could be utilized for phosphoric acid manufacture, because low sulphuric acid consumption 2.52 ton acid/ton P2O5 and better P2O5 recovery yield (94.71) was achieved. The dolomitic phosphate reserves of 4–5 million tons (having 5–6% MgO) remained problematic, giving low P2O5 recovery yield (89.25) and higher sulphuric acid consumption 4.08 tons acid/ton P2O5.Product acid from the dolomitic reserves upon concentration became paste like at 36–38% P2O5 and therefore, these indigenous dolomitic phosphate reserves could not be utilized for the production of phosphoric acid. 相似文献
Multiwalled carbon nanotube/polycaprolactone nanocomposites (MWNT/PCL) were prepared by in situ polymerization, whereby functionalized MWNTs (F-MWNTs) and unfunctionalized MWNTs (P-MWNTs) were used as reinforcing materials. The F-MWNTs were functionalized by Friedel-Crafts acylation, which introduced the aromatic amine (COC6H4-NH2) groups on the side wall. The F-MWNTs were chemically bonded with the PCL chains in the F-MWNT/PCL, as indicated by the appearance of the amide II group in the FT-IR spectrum. The TGA thermograms showed that the F-MWNT/PCL had better thermal stability than PCL and P-MWNT/PCL. The PCL and the nanocomposite nanofibers were prepared by an electrospinning technique. The nanocomposites that contain more than 2 wt% of MWNTs were not able to be electrospun. The bead of the F-MWNT/PCL nanofiber was formed less than that of the P-MWNT/PCL. The nanocomposite nanofibers showed a relatively broader diameter than the pure PCL nanofibers. The MWNTs were embedded within the nanofibers and were well oriented along the axes of the electrospun nanofibers, as confirmed by transmission electron microscopy. 相似文献
Oligo[aromatic diimidoselenium] (PADIS) is prepared from the reaction of the disubstituted aromatic compounds, namely, 1,4-phenylenediamine, 4,4-thiodianiline, 1,1-biphenylene-4,4-diamine, and 2,2-dithiodianiline, with selenium dioxide in refluxing absolute ethanol. The four materials are investigated by elemental analysis, electronic spectra, Fourier Transform-infrared spectroscopy, and [1H]NMR spectroscopy. The DC electrical conductivity variation with temperature in the range 300–500 K of the materials after annealing for 24 h at 100°C and after doping with 10% I2 is determined for comparison. 相似文献