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Additive manufacturing (AM) methods such as material extrusion (ME) are becoming widely used by engineers, designers and hobbyists alike for a wide variety of applications. Successfully manufacturing objects using ME three-dimensional printers can often require numerous iterations to attain predictable performance because the exact mechanical behavior of parts fabricated via additive processes are difficult to predict. One of that factors that contributes to this difficulty is the wide variety of ME feed stock materials currently available in the marketplace. These build materials are often sold based on their base polymer material such as acrylonitrile butadiene styrene or polylactic acid (PLA), but are produced by numerous different commercial suppliers in a wide variety of colors using typically undisclosed additive feed stocks and base polymer formulations. This paper aims to present the results from an experimental study concerned with quantifying how these sources of polymer variability can affect the mechanical behavior of three-dimensional printed objects. Specifically, the set of experiments conducted in this study focused on following: several different colors of PLA filament from a single commercial supplier to explore the effect of color additives and three filaments of the same color but produced by three different suppliers to account for potential variations in polymer formulation.

A set of five common mechanical and material characterization tests were performed on 11 commercially available PLA filaments in an effort to gain insight into the variations in mechanical response that stem from variances in filament manufacturer, feed stock polymer, additives and processing. Three black PLA filaments were purchased from three different commercial suppliers to consider the variations introduced by use of different feed stock polymers and filament processing by different manufacturers. An additional eight PLA filaments in varying colors were purchased from one of the three suppliers to focus on how color additives lead to property variations. Some tests were performed on unprocessed filament samples, while others were performed on objects three-dimensional printed from the various filaments. This study looked specifically at four mechanical properties (Young’s modulus, storage modulus, yield strength and toughness) as a function of numerous material properties (e.g. additive loading, molecular weight, molecular weight dispersity, enthalpy of melting and crystallinity).

For the 11 filaments tested the following mean values and standard deviations were observed for the material properties considered: p_a = 1.3 ± 0.9% (percent additives), M_w = 98.6 ± 16.4 kDa (molecular weight), Ð = 1.33 ± 0.1 (molecular weight dispersity), H_m = 37.4 ± 7.2 J/g (enthalpy of melting) and = 19.6 ± 2.1% (crystallinity). The corresponding mean values and standard deviations for the resulting mechanical behaviors were: E = 2,790 ± 145 MPa (Young’s modulus), E’ = 1,050 ± 125 MPa (storage modulus), S_y = 49.6 ± 4.93 MPa (yield strength) and U_t = 1.87 ± 0.354 MJ/m^³ (toughness). These variations were observed in filaments that were all manufactured from the same base polymer (e.g. PLA) and are only different in terms of the additives used by the manufacturers to produce different colors or different three-dimensional printing performance. Unfortunately, while the observed variations were significant, no definitive strong correlations were found between these observed variations in the mechanical behavior of the filaments studied and the considered material properties.

These variations in mechanical behavior and material properties could not be ascribed to any specific factor, but rather show that the mechanical of three-dimensional printed parts are potentially affected by variations in base polymer properties, additive usage and filament processing choices in complex ways that can be difficult to predict.

These results emphasize the need to take processing and thereby even filament color, into account when using ME printers, they emphasize the need for designers to use AM with caution when the mechanical behavior of a printed part is critical and they highlight the need for continued research in this important area. While all filaments used were marked as PLA, the feedstock materials, additives and processing conditions created significant differences in the mechanical behavior of the printed objects evaluated, but these differences could not be accurately and reliably predicted as function of the observed material properties that were the focus of this study.

The testing methods used in the study can be used by engineers and creators alike to better analyze the material properties of their filament printed objects, to increase success in print and mechanical design. Furthermore, the results clearly show that as AM continues to evolve and grow as a manufacturing method, standardization of feedstock processing conditions and additives would enable more reliable and repeatable printed objects and would better assist designers in effectively implementing AM methods.

Addresses the issue of valuation variation. The fundamental research question is to establish the range of valuations which a group of qualified valuers operating in the same market and using the same basic assumptions would produce in their estimation of price. It significantly extends the approach adopted by Hager and Lord and draws conclusions about different market sectors, locations and size of firms. The results of the survey show a wide variation in value across both rack rented and reversionary interests. In terms of the former over 80 per cent of all valuations produced a variation from the mean of less than 20 per cent with a corresponding figure of over 90 per cent for the reversionary investments. These levels of accuracy fall short of the contention that valuers can value to within 5‐10 per cent of market value.

Elevated temperature material properties are essential in predicting structural member's behavior in high-temperature exposures such as fire. Even though experimental methodologies are available to determine these properties, advanced equipment with high costs is required to perform those tests. Therefore, performing those experiments frequently is not feasible, and the development of numerical techniques is beneficial. A numerical technique is proposed in this study to determine the temperature-dependent thermal properties of the material using the fire test results based on the Artificial Neural Network (ANN)-based Finite Element (FE) model.

An ANN-based FE model was developed in the Matlab program to determine the elevated temperature thermal diffusivity, thermal conductivity and the product of specific heat and density of a material. The temperature distribution obtained from fire tests is fed to the ANN-based FE model and material properties are predicted to match the temperature distribution.

Elevated temperature thermal properties of normal-weight concrete (NWC), gypsum plasterboard and lightweight concrete were predicted using the developed model, and good agreement was observed with the actual material properties measured experimentally. The developed method could be utilized to determine any materials' elevated temperature material properties numerically with the adequate temperature distribution data obtained during a fire or heat transfer test.

Temperature-dependent material properties are important in predicting the behavior of structural elements exposed to fire. This research study developed a numerical technique utilizing ANN theories to determine elevated temperature thermal diffusivity, thermal conductivity and product of specific heat and density. Experimental methods are available to evaluate the material properties at high temperatures. However, these testing equipment are expensive and sophisticated; therefore, these equipment are not popular in laboratories causing a lack of high-temperature material properties for novel materials. However conducting a fire test to evaluate fire performance of any novel material is the common practice in the industry. ANN-based FE model developed in this study could utilize those fire testing results of the structural member (temperature distribution of the member throughout the fire tests) to predict the material's thermal properties.

This study reinvestigates the short-run and long-run inflation-hedging attributes of residential property assets in the Nigerian property market, based on variations in property types and location.

Data used for this study comprised the holding period returns of three residential property types, namely bungalow, block of flats and detached house during 1999–2018. These were obtained from property practitioners in Lagos, Abuja and Port Harcourt, respectively. The inflation values obtained from the National Bureau of Statistics were split into actual, expected and unexpected components. Fama and Schwert’s (1977) ordered least square (OLS) regression was used to assess the short-term inflation hedging efficacy. Afterwards, the long-run link between residential property and inflation was examined using the Johansen and Juselius cointegration test.

The results showed that despite the variations in hedging behaviour across property types in the three locations, residential property assets significantly provided protection over actual, expected and unexpected inflation in the short run based on the OLS regression analysis. The result of the Johansen and Juselius cointegration test also established a long-term link between the residential property assets and actual inflation. However, mixed results were found on the link between residential property and expected and unexpected inflation, as some of the assets did not effectively hedge these inflation components in the long run.

The study implied that the differences in property types and geographic locations are crucial in establishing the short-run and long-run inflation-hedging attributes of residential property assets and should be factored into consideration.

The paper complements the existing body of knowledge on the inflation-hedging attributes of residential property in emerging markets by determining the effects of variation in house types and geographic differences on the analysis.

The purpose of this paper is to rigorously determine the tensile properties of a selective laser sintering (SLS) material. Emphasis was placed on the anisotropy and inhomogeneity of the material, the repeatability of the SLS process, and the effect of age (actually moisture absorption) on the material properties.

Two builds of 144 dogbone tensile specimens each were tested, with 18 specimens stored for 43 days in a non‐desiccated environment before testing. Specimens were distributed throughout the build volume and aligned with the apparatus' principal axes. Tensile properties were treated statistically, using the t‐test to determine the differences between various samples.

The material was transversely isotropic in Young's modulus and strain to failure, and generally orthotropic in ultimate tensile strength. The material was inhomogeneous throughout the build volume and affected by age, with a 57 per cent reduction in University of Technology after 43 days (the changes in properties were suggested to be due to moisture absorption). Properties varied by up to 25 per cent from build‐to‐build with no change in nominal process parameters.

It was not possible to confirm the “ageing” effect was caused by moisture absorption, and further work is suggested in this area. The causes of inhomogeneity and the effect of re‐coater action should also be studied further.

This is the most complete study of an SLS material's mechanical properties to date. The statistical analyses used further allow increased confidence in the conclusions drawn. This is also the only study to use cross‐fill scanning to produce specimens, and, therefore, isolate the effect of the re‐coater action.

The composition and properties of milk are considerably important for dairy farmers, manufacturers and consumers. Despite the significant role of bovine milk in Iranian dairy products, there is little information about the effect of production season and location on the physicochemical properties of pasteurized milk as a final product. The purpose of this study was to investigate the effects of seasonal, geographical and product brand variations on the chemical components and physical properties of Iranian pasteurized bovine milk.

A total of 400 samples of pasteurized milk were obtained during a 12-month period, from April 2014 to March 2015, using random sampling. Chemical components (protein, fat, lactose, dry matter and solids-not-fat) and physical properties (freezing point, extraneous water content, titratable acidity, density and pH) of the collected samples were analyzed. A one-way ANOVA was used to perform the statistical analysis of data, and results were presented as the mean ± standard deviation.

It was found that the biochemical constituents and physical properties of pasteurized milk samples were linked to seasonal and geographical variation parameters. The milk sampled during spring and summer contained significantly less fat, protein and solids-not-fat (p < 0.05) than samples in autumn and winter. Also, samples in spring had a significantly higher (p < 0.05) extraneous water (0.8 per cent) compared to milk sampled in winter (−0.4 per cent). Samples in Maragheh and Mianeh contained the highest level of fat (2.82 per cent) and protein (3.09 per cent) content in the province. The sampled milk from the south (Mianeh and Hashtrud) and the northwest (Marand) had also significantly higher (p < 0.01) freezing points than the other areas. No significant differences (p > 0.01) were found in physicochemical properties in different product brands of the milk samples.

Seasonal and geographical parameters are crucial factors in the diversity of physicochemical parameters of commercial pasteurized milk. In this study, unlike the other studies, differences in milk product brand were not significant. Further research will be needed to assess other factors such as the effect of management practices and feeding strategies on farms.

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property Management Volumes 8‐18; Structural Survey Volumes 8‐18.

Index by subjects, compiled by K.G.B. Bakewell covering the following journals: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property Management Volumes 8‐18; Structural Survey Volumes 8‐18.

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property Management Volumes 8‐18; Structural Survey Volumes 8‐18.

Compiled by K.G.B. Bakewell covering the following journals published by MCB University Press: Facilities Volumes 8‐18; Journal of Property Investment & Finance Volumes 8‐18; Property Management Volumes 8‐18; Structural Survey Volumes 8‐18.