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This study aims to find out the average journal packing density (JPD) of Library and Information Science (LIS) research journals published across the world. The concept, JPD, means the average number of research articles published by a research journal in one volume. Accordingly, the undergoing study evaluates the average number of research articles published in each volume of each research journal published in the field of LIS at the global level. Some other key aspects evaluated include the number of LIS research journal publishing countries, average JPD of LIS research journals at the continental level, etc.

This study is purely based on secondary data retrieved from SCImago, which is SCOPUS data. Keeping in view the objectives of this study, the data about research articles published in all LIS research journals during the period 2015 through 2019 were retrieved to undertake the study.

From the data analysis, it emerged that 256 research journals duly indexed by SCOPUS are published in the field of LIS across 36 countries. In all 48,596 research articles were published from 2015 to 2019 in these research journals at an average of 44.71 research articles per journal per volume. More than 75% of LIS research journals are published from Germany, Spain, Netherlands, the USA and the UK. Research journals published from the USA have higher JPD of 53.09 research articles per journal per volume, which is 18.74% higher than the average global JPD of LIS research journals. 50% of LIS research journal publishing countries are from Europe and the majority 52.55% LIS research articles were published in European LIS research journals. The average JPD of LIS research journals published from North America is 51.73 research articles per journal per volume, which is the highest across continents.

Standardization of JPD of research journals irrespective of the subject discipline they are published in is important for many reasons and the foremost being, such standardization helps in keeping at bay the predatory research journals, which normally float such packing density norms, with the sole aim to earn money in the shape of manuscript handling charges, thereby publishing a far greater number of research article in each issue of a journal than the average research articles published by a research journal.

Very few studies have been conducted around the concept JPD, especially by the authors of this particular study. This study has however been particularized to the LIS subject discipline, while the findings add to existing lot of study already undertaken, hence outcome can be generalized.

The study aims to assess the journal packing density (JPD) of the research journals published across different subject discipline at the global level. The concept of JPD is aimed to compute the average number of research articles published per volume or per issue of a research journal in any given subject discipline. The study also discusses about the leading research journals publishing countries and continents across the world and their average JPD. An attempt has also been made to identify the leading research counties having maximum JPD in any given subject discipline.

The study covers 27 major research subject disciplines widely popular all across the globe. To undertake the present study, data were retrieved from SCImago Journal and Country Ranking.

In all, 36,081 research journals were indexed by Scopus across 27 major subject disciplines at the global level till 2015. During the period 2013-2015, 11,023,122 research articles were published in 36,081 research journals across 27 major subject disciplines at the global level at an average of 101.84 research articles per journal per volume. This means the average JPD of the research journals at the global level is 101.84 research articles per journal per volume. Chemistry, physics and astronomy and multidisciplinary journals are the three leading subject disciplines to have the maximum JPD, namely, 266.66, 253.92 and 242.53 research articles per journal per volume. JPD of research journals published in the sciences is higher than the JPD of research journals published in the social sciences and humanities. Business, management and accounting, social sciences and arts and humanities are three subject disciplines having lowest JPD, namely, 44.26, 35.68 and 32.66 research articles per journal per volume, respectively. China, Ireland and The Netherlands recorded the highest average JPD in the research journals published from these counties, namely, 213.39, 178.44 and 135.31 research articles per journal per volume, respectively.

Countries from where a lesser number of research journals are indexed by the popular indexes, such as Scopus, Web of Science, etc., face greater pressure of publishing. To ooze out this pressure, there is need to index more and more research journals from these countries and that can be done only by improving and maintaining the research standard over a period.

The study is original and the first of its kind undertaken at the global level across all the major subject disciplines.

This study aims to practically determine the optimum proportion of aggregates to attain the desired strength of geopolymer concrete (GPC) and then compare the results using established analytical particle packing methods. The investigation further aims to assess the influence of various amounts of recycled aggregate (RA) on properties of low-calcium fly ash-based GPC of grade M25.

Fine and coarse aggregates were blended in various proportions and the proportion yielding maximum packing density was selected as the optimum proportion and they were compared with analytical models, such as Modified Toufar Model (MTM) and J. D. Dewar Model. RAs for this study were produced in laboratory and they were used in various amounts, namely, 0%, 50% and 100%. 12M NaOH solution was mixed with Na₂SiO₃ in the ratio of 1:2. The curing of concrete was done at the temperatures of 60° and 90 °C for 24, 48 and 72h.

The experimentally obtained optimum proportion of coarse to fine aggregate was 60:40 for all amounts of RA. Meanwhile, MTM and Dewar Model resulted in coarse aggregate to fine aggregates as 40:60, 45:55, 55:45 and 55:45, 35:65, 60:40, respectively, for 0% 100% and 50% RAs. The compressive strength of GPC elevated with the increase in curing regime. In addition, the ultrasonic pulse velocity also displayed a similar trend as that of strength.

The GPC with 50% RAs may be considered for use, as it exhibited superior properties compared to GPC with 100% RAs and was comparable to GPC with natural aggregates. Furthermore, compressive strength is correlated with split tensile strength and ultrasonic pulse velocity.

This study aims to experimentally investigate the effect of the powder material characteristics on the qualities of the binder jetting additive manufacturing parts both before and after post processing (sintering).

Three different types of the 316L stainless steel powder feedstock with various mean particle sizes and size distributions were studied. The influence of the powder particle size distributions and pore sizes on the powder bed packing densities and on the dynamics of the binder droplet-powder bed interactions were characterized. In addition, the surface roughness and densities of these parts both in the green state and after sintering were studied.

The results revealed the significant role of the powder feedstock characteristics on the liquid binder/powder bed interaction and consequently on the dimensional accuracies of the green parts. It was observed that the parts printed with the smaller mean particle sizes resulted in better surface finish and higher final densities after sintering. Furthermore, the hardness of the sintered parts produced with smaller powder particles exhibited higher values compared to the parts fabricated with the larger particles. On the other hand, larger particle sizes are advantageous for various green part qualities including the dimensional accuracies, green part densities and surface roughness.

This study establishes more comprehensive correlations between the powder feedstock characteristics and various quality criteria of the printed binder jetting components in both green and sintered states. These correlation are of critical importance in choosing the optimal process parameters for a given material system.

The purpose of this paper is to extend the previous study [Computer Methods in Applied Mechanics and Engineering 340: 70-89, 2018] on the development of a novel packing characterising system based on principal component analysis (PCA) to quantitatively reveal some fundamental features of spherical particle packings in three-dimensional.

Gaussian quadrature is adopted to obtain the volume matrix representation of a particle packing. Then, the digitalised image of the packing is obtained by converting cross-sectional images along one direction to column vectors of the packing image. Both a principal variance (PV) function and a dissimilarity coefficient (DC) are proposed to characterise differences between different packings (or images).

Differences between two packings with different packing features can be revealed by the PVs and DC. Furthermore, the values of PV and DC can indicate different levels of effects on packing caused by configuration randomness, particle distribution, packing density and particle size distribution. The uniformity and isotropy of a packing can also be investigated by this PCA based approach.

Develop an alternative novel approach to quantitatively characterise sphere packings, particularly their differences.

In binder jetting, the interaction between the liquid binder droplets and the powder particles defines the shape of the printed primitives. The purpose of this study is to explore the interaction of the relative size of powder particles and binder droplets and the subsequent effects on macro-scale part properties.

The effects of different particle size distribution (5–25 µm and 15–45 µm) of stainless steel 316 L powders and droplet sizes (10 and 30 pL) on part density, shrinkage, mechanical strength, pore morphology and distribution are investigated. Experimental samples were fabricated in two different layer thicknesses (50 and 100 µm).

While 15–45 µm samples demonstrated higher green density (53.10 ± 0.25%) than 5–25 µm samples (50.31 ± 1.06%), higher sintered densities were achieved in 5–25 µm samples (70.60 ± 6.18%) compared to 15–45 µm samples (65.23 ± 3.24%). Samples of 5–25 µm also demonstrated superior ultimate tensile strength (94.66 ± 25.92 MPa) compared to 15–45 µm samples (39.34 ± 7.33 MPa). Droplet size effects were found to be negligible on both green and sintered densities; however, specimens printed with 10-pL droplets had higher ultimate tensile strength (79.70 ± 42.31 MPa) compared to those made from 30-pL droplets (54.29 ± 23.35 MPa).

To the best of the authors’ knowledge, this paper details the first report of the combined effects of different particle size distribution with different binder droplet sizes on the part macro-scale properties. The results can inform appropriate process parameters to achieve desired final part properties.

This paper aims to study the packing density of printed paths on different substrate materials. It presents problems which appear when the necessity of printing one or more narrow paths occurs.

A piezoelectric printhead containing nozzles with a diameter of 35 µm was used for printing nanoparticle silver ink on different polymer substrates which were treated by plasma or not treated at all. The shape, defects, resistance and printing parameters for the printed paths were analysed.

The obtained results allow the identification of the sources of the technological problems in obtaining a high packing density of the paths in a small area of substrate and the repeatable prints.

The study could have limited universality because of the chosen research method; printhead, ink, substrate materials and process parameters were arbitrarily selected. The authors encourage the study of other kinds of conductive inks, treatment methods and printing process parameters.

The study includes practically useful information about widths, shapes, defects and the resistance of the paths printed using different technological parameters.

The study presents the results of original empirical research on problems of the packing density of inkjet printed paths on a small area of substrate and identifies problems that must be resolved to obtain effective interconnections in the inkjet technology.

The purpose of this paper is to acquire thermal conductivities of both fresh and preheated polyamide 12 powder under various conditions to provide a basis for effective and accurate control during the laser sintering (LS) process.

A Hot Disk® TPS 500 thermal measurement system using a transient plane source (TPS) technology was employed for thermal conductivity measurements. Polyamide 12 powder was packed at different densities, and different carrier gases were used. Tests were also performed on fully dense laser sintered polyamide 12 to establish a baseline.

Polyamide 12 powder thermal conductivity varies with packing density and temperature, which is approximately one-third bulk form thermal conductivity. Inter-particle bonding is the primary factor influencing polyamide 12 thermal conductivity.

Limited ranges of density were tested, and the carrier gas needed carefully control to prevent powder oxidation. Thermal properties obtained were not tested in the LS process.

This experimental result could be used to enhance thermal control during the LS process.

The purpose of this paper is to study the effects of particle size distribution, component ratio, particle packing arrangement, and chemical constitution on the laser sintering behaviour of blended hypoeutectic Al‐Si powders.

A range of bimodal and trimodal powder blends were created through mixing Al‐12Si and pure aluminium powder. The powder blends were then processed using selective laser sintering to investigate the effect of alloy composition, powder particle size and bed density on densification and microstructural evolution.

For all of the powder blends the sintered density increases with the specific laser energy input until a saturation level is reached. Beyond this saturation level no further increase in sintered density is obtained for an increase in specific laser energy input. However, the peak density achieved for a given blend varied significantly with the chemical constitution of the alloy, peaking at approximately 9 wt% Si. The tap density of the raw powder mixture (assumed to be representative of bed density) was also a significant factor.

This is the first study to consider the usefulness of silicon as an alloying element in aluminium alloys to be processed by selective laser sintering. In addition the paper outlines the key factors in optimising processing parameters and powder properties in order to attain sound sinterability for direct laser sintered parts.

The primary objective of this two part study was to show theoretically how pigment cluster voids and pigment distribution can influence the critical pigment volume concentration (CPVC) and consequently the properties of a dry coating. In Part I of this study a pigment clustering model with an analytical solution has been developed that was a modification of an earlier model by Fishman, Kurtze, and Bierwagen that could only be solved numerically.

The original derivation of the clustering concept developed by Fishman et al. resulted in a mathematical analysis which was only able to be solved numerically and was found to be very tedious to utilize directly. In this study, a new successful derivation utilizing some of the original concepts of Fishman et al. was generated and shown to result in a practical and much more useable analytical analysis of the clustering concept. This new model was then applied directly to quantify the influence of flow agents or surfactants in a coating formulation on the CPVC as described by Asbeck.

It was found that the largest deviation from 100 per cent pigment dispersion with no pigment clusters occurred just before and just after the ultimate CPVC (UCPVC). A theoretical relationship was also found between the pigment cluster dispersion coefficient, C_q, and CPVC. This result was consistent with the experimental relationship between CPVC and the per cent flow additive as found by Asbeck. The density ratio of overall coating to the pigment density was found to go through a maximum at a global volume fraction of pigment that was slightly greater than the UCPVC as expected for a mechanical property. It was also identified that mechanical failure of most coating formulations should be apparent at either the “Lower Zero Limit” or the “Upper Zero Limit” global volume fraction pigment as defined in this study.

While the experimental measurement of the parameters to isolate the clustering concepts introduced in this study may be difficult, it is expected that better quantitative measurement of clustering concepts will eventually prove to be very beneficial to providing improved suspension applications including coatings.

The theoretical relationship developed in this study between the pigment cluster dispersion coefficient, C_q, and CPVC and the experimental relationship between CPVC and the per cent flow additive found by Asbeck inferred a direct relationship between C_q and the per cent flow additive. Consequently, it was shown that the theoretical pigment cluster model developed in this study could be directly related to the experimental matrix additive composition in a coating formulation. The implication is that the measurement tool introduced in this study can provide better measurement and control of clustering in coatings and other suspension applications.

In this study, a new successful derivation utilizing some of the original concepts of Fishman et al. was generated and shown to result in a practical and much more useable analytical analysis of the clustering concept. This new model was then applied directly to quantify the influence of flow agents or surfactants in a coating formulation on the CPVC as described by Asbeck.