Evaluating human versus machine learning performance in classifying research abstracts

We study whether humans or machine learning (ML) classification models are better at classifying scientific research abstracts according to a fixed set of discipline groups. We recruit both undergraduate and postgraduate assistants for this task in separate stages, and compare their performance against the support vectors machine ML algorithm at classifying European Research Council Starting Grant project abstracts to their actual evaluation panels, which are organised by discipline groups. On average, ML is more accurate than human classifiers, across a variety of training and test datasets, and across evaluation panels. ML classifiers trained on different training sets are also more reliable than human classifiers, meaning that different ML classifiers are more consistent in assigning the same classifications to any given abstract, compared to different human classifiers. While the top five percentile of human classifiers can outperform ML in limited cases, selection and training of such classifiers is likely costly and difficult compared to training ML models. Our results suggest ML models are a cost effective and highly accurate method for addressing problems in comparative bibliometric analysis, such as harmonising the discipline classifications of research from different funding agencies or countries.National Research Foundation (NRF)Published versionThe study was partially funded by the Singapore National Research Foundation, Grant No. NRF2014-NRF-SRIE001-02

Advanced composite materials produced by novel spray formed in-situ reaction processes

This project performed in-situ spray reactions on two different materials systems: (A) NiCoCrA1Y/yttria stabilized zirconia (YSZ) and (B) mullite-zirconia from reaction spraying of zircon and alumina

Development of advanced materials by a high velocity spray forming technique

41 p.This final report on the Applied Research Project No. RP 56/92 presents the thermal spray processing system that is applied to produce fine ceramic-based and metal-based composite powders and coatings for wear resistant, high performance metal matrix composites (MMC) and biomedical coatings. A high velocity oxy-fuel (HVOF) system was set up. This thermal spray technique was able to apply various types of ceramic and metal alloy coatings through high velocity spray forming or depoition.RP 56/9

Development of a ceramic processing system for microelectronics and thermo-mechanical applications

24 p.This final report on the Applied Research Project No. RP 39/89 presents the ceramic processing systems capable of producing fine ceramic powders and coatings for microelectronics and thermo-mechanical applications. A modification to a prior experimental setup for preparation of thin ceramic substrates for multilayer capacitors (MLCs) using a tape casting method was successfully achieved by the incorporation of an ultrasonic probe that enhanced the distribution of reinforcements in the ceramic slurry.RP 39/8

Vliv teploty a rychlosti částic práškového hydroxyapatitu na charakteristiky plazmově nanášených vrstev

This paper presents a systematic research on the process of thermal spraying of HA encompassing all stages of layer deposition: powder production and characterization (optimized production led to spherical 29.29 - 50.51 um powder with 0.0% content of tri-calcium phosphate [TCP] or tetra-calcium phosphate [TTCP] phases), plasma jet properties influence on the in-flight powder properties (major influence of spray distance factor), the influence of the in-flight temperature and velocity of hydroxyapatite powder particles (ranges of 2294 K–2708 K and 152 m/s – 291 m/s) on the final characteristics of the deposited coatings. Six combinations of the system parameters leading the low-medium-high in-flight properties were selected and the respective coatings were investigated, with some data in contradiction to previously published results. It was found that the temperature of the particles plays a critical role for the development of detrimental CaO (content increase of up to 14.6%) and metastable TTCP (up to 49.5%) phases in the coatings. Particle in-flight velocity was found to influence the open porosity of the coatings (8.8%–27.9%) and has an impact on the micro-hardness and moduli of the coatings (relative differences of up to 2.8 times). Joint incidence of both in-flight properties was found to significantly influence the microstructure of the coatings and its respective surface roughness levels (Ra = 7.4–19.4 um). The morphology of impinging splats was found to be influenced by both the in-flight velocity (dominant factor) and temperature (secondary factor) of the HA particles.Tento článek představuje systematickou studii procesu tepelného nanášení hydroxyapatitu (HA) zahrnující všechny tři stupně depozice vrstev: primární výrobu a následnou charakterizaci HA prášků (optimalizovaní produkce vedlo k výrobě sférického prášku velikostí 29.29 - 50.51 um s 0.0% obsahem tri-kalcium fosfátů [TCP] a tetra-kalcium fosfátů [TTCP]), hodnocení vlivu vlastností plazmového plamene na letové charakteristiky prášků (byl zjištěn marginální vliv faktoru stříkací vzdálenosti) a vliv teploty a letové rychlosti částic hydroxyapatitu (byly naměřeny rozsahy 2294 K–2708 K a 152 m/s – 291 m/s) na celkové vlastnosti nanesených vrstev. V této studii bylo dále zvoleno šest kombinací systémových parametrů, vedoucích k nízkým-středním-vysokým hodnotám letových parametrů a byly zkoumány charakteristiky vlastnosti šesti odpovídajících nástřiků. Některé dosažené výsledky jsou v přímém rozporu s předchozími publikovanými studiemi. Bylo zjištěno, že letová teplota částic hraje kritickou úlohu pro vývoj škodlivé fáze CaO (zjištěno zvýšení výskytu až 14.6%) a metastabilní fáze TTCP (až 49.5%) v deponovaných vrstvách. Letová rychlost částic ovlivňuje otevřenou porozitu nástřiků (8.8%–27.9%) a má dopad na mikro-tvrdost a elastický modul vrstev (naměřené relativní rozdíly až 2.8krát). Bylo zjištěno, že společné působení obou letových faktorů významně ovlivňuje mikrostrukturu nástřiků a odpovídající hodnoty povrchových drsností (Ra = 7.4–19.4 um). Taktéž morfologie dopadajících částic je ovlivněna oběma faktory - letovou teplotou (dominantní působení) a letovou rychlostí (sekundární faktor) částic HA

Characteristics of the nanostructures in thermal sprayed hydroxyapatite coatings and their influence on coating properties

There are generally two methods for depositing nanostructured coatings, retaining the nanostructures from starting feedstock and forming novel nanostructures through quenching. The present study utilized spray-dried nanostructured hydroxyapatite (nSD-HA) feedstock for coating/splat deposition. The nanostructures were characterized by transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM). Results revealed that the rod-shaped nano-grains in the starting HA particles (< 500 nm in length and 40–70 nm in diameter) encountered two major experiences: enlargement due to unmelt state and reorganization due to melting–solidification. The molten part of the particles results in formation of spherical nanosized particles with grain sizes of 30–110 nm. TEM observation of the HA splats demonstrates consistent nanostructures. The unmelted part of individual nSD-HA particles showed significantly enlarged grains along radial direction (< 550 nm in length and < 400 nm in diameter). In addition, individual hexagonal grains were observed in the HVOF coating made from 30 ± 10 μm powder. The grains have the size of < 250 nm in height and < 50 nm in side length and are perpendicular to the coating/substrate interface. The nanostructures within the coatings contribute to an increased Young's modulus with up to 60.11 GPa, however, they showed detrimental effect on adhesion of the coatings. In vitro cell culturing revealed marked attachment and proliferation of the osteoblast cells on the nanostructured coatings. However, the results suggest that the nanostructures possess less importance than the phases (preferably high content of crystalline HA) on enhancing the cell proliferation.Accepted versio

Chemical analysis of silica doped hydroxyapatite biomaterials consolidated by a spark plasma sintering method

Silica (SiO2) and the silicate-based biomaterials play an important role due to their in vitro and in vivo biological response. The present study synthesized a novel nano-structured amorphous silica doped hydroxyapatite (HA) via an aqueous precipitation route. HA was prepared with 0, 1, 3 and 5 wt% silica, which are comparable to the measured silicon content of natural bone. After spray drying into micron sized powders, the silica doped HA (SiHA) powders were consolidated at 1000 C with a dwell time of 3 min using a spark plasma sintering (SPS) technique. X-ray diffraction analysis showed a main apatite phase with minor secondary b-tricalcium phosphate (b-TCP) was observed in the as-consolidated SiHA compacts. Substitution of PO3- 4 by SiO4- 4 in the apatite structure resulting in a small increase in the lattice parameters in both a-axis and c-axis of the unit cell were identified by X-ray photoelectron spectrometer (XPS) analysis and Raman spectrometer investigation. The cell culture in vitro investigation demonstrated that the presence of silicon in the SPS consolidated compacts contributed to the relatively high cell proliferation ability when compared with phase pure HA.Accepted versio

Influence of international co-authorship on the research citation impact of young universities

We investigated the effect of international collaboration (in the form of international co-authorship) on the impact of publications of young universities (< 50 years old), and compared to that of renowned old universities (> 100 years old). The following impact indicators are used in this study, they are: (1) the 5-year citations per paper (CPP) data, (2) the international co-authorship rate, (3) the CPP differential between publications with and without international co-authorships, and (4) the difference between the percentage of international co-authored publications falling in the global top 10 % highly cited publications and the percentage of overall publications falling in the global top 10 % highly cited publications (D%Top10%). The increment of 5-year (2010–2014) field weighted citation impact (FWCI) of internationally co-authored papers over the 5-year overall FWCI of the institutions in SciVal is used as another indicator to eliminate the effect of discipline difference in citation rate. The results show that, for most top institutions, the difference between the citations per paper (CPP) for their publications with and without international co-authorship is positive, with increase of up to 5.0 citations per paper over the period 1996–2003. Yet, for some Asian institutions, by attracting a lot of researchers with international background and making these collaborating ‘‘external’’ authors as internal researchers, these institutions have created a special kind of international collaboration that are not expressed in co-authorship, and the CPP gaps between publications with and without international co-authorship are relatively small (around 0–1 citations per paper increment) for these institutions. The top old institutions have higher CPP than young institutions, and higher annual research expenditures; while young universities have a higher relative CPP increment for the current 5-year period over the previous 5-year period. The D%Top10% for international co-authored publications is generally higher than that for all journal publications of the same institution. With the increase of international co-authorship ratio, the mean geographical collaboration distance (MGCD, an indication of increased international co-authorship) of one institution based on the Leiden Ranking data also increases, and young institutions have relatively higher CPP increment over MGCD increment. International co-authorship has a positive contribution to the FWCI of the institution, yet there are untapped potential to enhance the collaboration among young institutions.Published versio

Revealing key topics shifts in thermal barrier coatings (TBC) as indicators of technological developments for aerospace engines

Thermal barrier coating (TBC) systems reduce the temperature of the metallic substrate of aerospace engines, resulting in improved component durability, better fuel economy and performance. Scientific research and innovation on TBC systems evolves rapidly and diversely over the years. Hence, an understanding of the research and innovation pathways on TBC systems is extremely important for the future development of aerospace engines. This study examines research publications and patents on TBC during 1980–2019. While USA led the TBC publication output from 1980 to 2010, China takes the lead after 2011 and India too is emerging noticeably on TBC research. The citation impact of publications reveal key topic shifts. Distinct peaks identified for (1) materials sciences during 1998–2003; (2) energy during 2001–2007, and (3) chemical engineering during 2009–2018. The visual mappings of author keywords of the publications reveal the progress of TBC technology. Results show shifts in deposition techniques for TBC coating preparation, and thermal management in the engines. The journal papers cited by patents have low correlation to the highly cited papers. This paper introduced an innovation relevance indicator to gauge the relevance of an institution’s scientific research to technological innovation. This novel indicator reveals the industry relevant work among the active institutions and companies with patents in TBC technologies. Universities with significant number TBC patents fall into two broad categories, (1) those who have high (> 70%) collaborations on patents filed, and (2) those that filed patents without existing external collaborations.This study is supported by the Ministry of Education Singapore AcRF Tier 1 grant RG141/17