Investigation of Ce(III) promoter effects on the tri- metallic Pt, Pd, Ni/MgO catalyst in dry-reforming of methane

Taufiq Yap Yun Hin/ / / Faris A. J. Al-Doghachi, Umer Rashi

Faculty Trio Recital

Carla Trynchuk (violin), Karin Thompson (cello), and Chi Yong Yun (piano) featuring works by Mozart, Fauré and Piazzolla.https://digitalcommons.andrews.edu/events-2017-2018/1017/thumbnail.jp

Calibration and accuracy assessment of Leica ScanStation C10 terrestrial laser scanner

Requirement of high accuracy data in surveying applications has made calibration procedure a standard routine for all surveying instruments. This is due to the assumption that all observed data are impaired with errors. Thus, this routine is also applicable to terrestrial laser scanner (TLS) to make it available for surveying purposes. There are two calibration approaches: (1) component, and (2) system calibration. With the intention to specifically identify the errors and accuracy of the Leica ScanStation C10 scanner, this study investigates component calibration. Three components of calibration were performed to identify the constant, scale error, accuracy of angular measurement and the effect of angular resolution for distance measurement. The first calibration has been processed using closed least square solutions and has yielded the values of constant (1.2 mm) and scale error (1.000008879). Using variance ratio test (F-Test), angles observation (horizontal and vertical) for Leica C10 scanner and Leica TM5100A theodolite have shown significance difference. This is because the accuracy of both sensors are not similar and these differences are 0.01 and 0.0075º for horizontal and vertical measurements, respectively. Investigation on the resolution setting for Leica C10 scanner has highlighted the drawback of the tilt-and-turn target. Using the highest resolution, Leica Cyclone software only able to recognize the tilt-and-turn target up to 10 m distance compare to 200 m for the black and white target

A Hierarchical Self-Attentive Model for Recommending User-Generated Item Lists

User-generated item lists are a popular feature of many different platforms. Examples include lists of books on Goodreads, playlists on Spotify and YouTube, collections of images on Pinterest, and lists of answers on question-answer sites like Zhihu. Recommending item lists is critical for increasing user engagement and connecting users to new items, but many approaches are designed for the item-based recommendation, without careful consideration of the complex relationships between items and lists. Hence, in this paper, we propose a novel user-generated list recommendation model called AttList. Two unique features of AttList are careful modeling of (i) hierarchical user preference, which aggregates items to characterize the list that they belong to, and then aggregates these lists to estimate the user preference, naturally fitting into the hierarchical structure of item lists; and (ii) item and list consistency, through a novel self-attentive aggregation layer designed for capturing the consistency of neighboring items and lists to better model user preference. Through experiments over three real-world datasets reflecting different kinds of user-generated item lists, we find that AttList results in significant improvements in NDCG, Precision@k, and Recall@k versus a suite of state-of-the-art baselines. Furthermore, all code and data are available at https://github.com/heyunh2015/AttList.Comment: Accepted by CIKM 201

Letter re: Comparison of acetabular and femoral morphologies on hip, pelvic, and lumbar radiographs (Yun et al.)

YesWe read with interest the recent article by Yun et al. [1] comparing acetabular and hip measurements across pelvis, hip and lumbar spine radiographs. The authors assert that lumbar radiographs can be utilised in place of routine pelvis radiographs for these measurements. The example lumbar spine radiograph (figure 2) appears to be an abdominal image, with a contrast urogram. Indeed, standard texts [2,3] confirm that the anteroposterior lumbar spine radiograph should not include any coverage of the hips as appropriate collimation should limit the anatomy to T12 superiorly, lower sacrum inferiorly and the sacroiliac joints laterally, which would exclude the hip joints. Thus assessing any hip measurements on an appropriately collimated lumbar spine radiograph should not be possible. This is further compounded by the description of the centring point within their study (iliac crest), which varies from the internationally recognised standard of lower costal margin/L3 [2,3]

Synthesis and Physico-Chemical Properties of Nanosized Vanadium Phosphorus Oxide, and its Use as Catalyst in Selective Oxidation of n-Butane to Maleic Anhydride

In this study, nanosized vanadium phosphorus oxide (VPO) catalyst was synthesized via a new organic route. The synthesized nanosized VPO catalyst was compared with conventional VPO catalyst which was prepared via conventional organic route. Besides, various metal dopants i.e zirconium (Zr), zinc (Zn), nickel (Ni), molybdenum (Mo), manganese (Mn), niobium (Nb), iron (Fe), copper (Cu), chromium (Cr), cerium (Ce) and cobalt (Co) also used in this study in order to investigate the role of metal dopants on the nanosized VPO catalyst. The physico-chemical properties of the synthesized catalysts were characterized by using x-ray diffraction (XRD), BET surface area measurement, redox titration, inductively coupled plasma –atomic emission spectroscopy (ICP-AES), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) and temperature programmed reduction in H2. The catalytic properties of the synthesized catalysts were carried out by using an on-line microreactor system. Results show that the nanosized VPO catalysts successfully synthesized via new organic route in far less duration i.e. 13 h compared to conventional organic route i.e. 109 h with good properties of the VPO catalysts. XRD pattern of the synthesized VPO catalysts showed the major peak of pyrophosphate, (VO)2P2O7 phase. However, the major peaks for nanosized VPO catalyst especially for (020), (204) and (221) phases are shown to be more prominent than those of conventional VPO catalyst. Besides, the new organic route also produced high surface area VPO catalysts with 5 times larger than conventional VPO catalyst. Formation of thin and increasing of platelets for nanosized VPO catalyst was also observed in SEM micrographs. Furthermore, particle size of this catalyst was found in nanoscale range (40-60 nm) as was proved by TEM. High amount of O2- and O- species removed for nanosized VPO was obtained by H2-TPR directly lead to a significant improvement in n-butane conversion at 673 K and also at lower temperatures (643 and 623 K) with higher maleic anhydride (MA) selectivity for the respective temperatures. The introduction of various metal dopants into the lattices of VPO catalyst did not alter the phase of hemihydrate precursors and the final catalysts. There are small variations can be observed on the surface area, redox titration and average vanadium oxidation state for the nanosized doped VPO catalysts compared to the nanosized undoped VPO catalyst. On the other hand, the incorporation of 1% Nb, Ni, Ce, Zr, Zn, Cr and Fe successfully reduced the particle size below than 40 nm. Moreover, the certain metal dopants can induced the amount of oxygen O2- and O- species removed especially for Ce, Cr and Ni doped catalysts. These fascinating features gave drastic increment for n-butane conversion and maleic anhydride (MA) selectivity at higher and lower temperatures (673, 643 and 623 K). The selectivity of maleic anhydride (MA) of all the synthesized nanosized VPO catalysts at lower temperatures i.e. 643 and 623 K are comparable with the conventional VPO catalyst at higher temperature, 673 K

Knowledge Engineering in Search Engines

With large amounts of information being exchanged on the Internet, search engines have become the most popular tools for helping users to search and filter this information. However, keyword-based search engines sometimes obtain information, which does not meet user’ needs. Some of them are even irrelevant to what the user queries. When the users get query results, they have to read and organize them by themselves. It is not easy for users to handle information when a search engine returns several million results. This project uses a granular computing approach to find knowledge structures of a search engine. The project focuses on knowledge engineering components of a search engine. Based on the earlier work of Dr. Lin and his former student [1], it represents concepts in the Web by simplicial complexes. We found that to represent simplicial complexes adequately, we only need the maximal simplexes. Therefore, this project focuses on building maximal simplexes. Since it is too costly to analyze all Web pages or documents, the project uses the sampling method to get sampling documents. The project constructs simplexes of documents and uses the simplexes to find maximal simplexes. These maximal simplexes are regarded as primitive concepts that can represent Web pages or documents. The maximal simplexes can be used to build an index of a search engine in the future

On the mechanism of the selective oxidation of n-butane, but-1-ene and but-1,3-diene to maleic anhydride over a vanadyl pyrophosphate catalyst

The mechanism of the selective partial oxidation of n-butane, but-1-ene and but-1,3-diene over a vanadyl phosphate catalyst has been investigated by temperature-programmed desorption (TPD) and by anaerobic temperature-programmed oxidation (TPO). TPD showed lattice oxygen to be desorbed in two states at 998 and 1023 K. The anaerobic TPO of n-butane produced butene and butadiene at 1020 K; anaerobic TPO of but-1-ene produced butadiene and furan at 990 K and dehydrofuran at 965 K, while anaerobic TPO of but-1,3-diene produced dehydrofuran at 970 K, furan at 1002 K and maleic anhydride at 1148 K. The total amount of oxygen removed from the lattice in these anaerobic selective partial oxidations was the same as that evolved from the vanadyl phosphate catalyst by TPD. This, and the fact that the selective oxidation reactions occurred at the same temperature at which the oxygen evolves from the lattice, suggests that the lattice oxygen is uniquely selective when it appears at the surface of the catalyst. (Under identical conditions of flow rate, weight of catalyst, heating rate etc., the reaction of n-butane or of but-1,3-diene in air produced only CO2 and H2O.