Potential Of Different Materials Research Articles

Assessment method of carbonation degree and activity of a wide range of calcium/magnesium containing solids

This work provides a systematic analysis and comparison of the assessment methods for determining the carbonation degree of materials containing calcium or magnesium. The analysis is conducted from three key perspectives, namely the consumption of carbonation reactive components, the production of carbonation product and the dry mass change resulted from carbonation reaction. The carbonation degree of steel slag, tricalcium silicate and carbide slag were assessed at liquid-to-solid ratios of 0 and 0.15 using quantitative X-ray diffraction, thermogravimetry and weighing at temperature of 25 °C, relative humidity of 60% and carbon dioxide concentration of 40%. The utilization of scanning electron microscope was employed to reveal the significant impact of liquid water on the carbonation degree. The results indicate that the carbonation degrees obtained by X-ray diffraction and thermogravimetry are quite similar, whereas the values obtained through weighing method drift away a little, particularly when liquid water is present. Nevertheless, all the methods investigated in this study exhibit great consistency and reliability, including the dry mass change method given its acceptable deviation from others and its convenience in testing. Furthermore, a novel method on assessing the carbonation activity is proposed based on the 24-h carbonation degree at the liquid-to-solid ratio of 0.15, which enables to efficiently distinguish the carbonation potential of different materials. In the end, carbonation activity inventory is established in which a wide range of calcium/magnesium contained materials are categorized into five groups, suggesting its suitability for evaluating the carbonation activity of various solid wastes and cement-based materials.

Synergistic effect between tannic acid-Fe3+ and chitosan hydrogel-coated covalent organic framework: Endowing better nanofiltration performance and stability

The weak interfacial interaction of nanomaterials and substrate is an important factor affecting the stability and rejection of nanofiltration membranes. Herein, two materials of covalent organic framework modified by chitosan hydrogels (CH@COF) and tannic acid (TA)-Fe3+ served as an interlayer of the thin-film composite (TFC) membrane to overcome this problem. The synergistic effect between CH@COF and TA-Fe (such as constructing stable chemical bonds between the polyamide layer and substrate, increasing the degree of cross-linking of the polyamide layer, and decreasing its thickness) endows the TFC/TA-Fe(CH@COF) membrane with excellent nanofiltration performance and stability. Its water permeability was 16.17 L m−2 h−1 bar−1, which was 185% of that of the TFC-control membrane (8.74 L m−2 h−1 bar−1), and the rejections of the membrane for norfloxacin, ciprofloxacin, and ofloxacin were 94.89%, 99.07%, and 99.10%, respectively. In addition, its flux recovery rate (FRR) values for high-concentration sodium alginate and bovine serum albumin were 98.32% and 97.99%, respectively, indicating outstanding antifouling performance. This work emphasizes the synergy and potential of different materials as an interlayer in high-performance TFC membranes.

Feasibility of Child-Resistant and Senior-Friendly Press-Through Packages: Potential of Different Materials

Press-through packaging (PTP) is the most common type of drug packaging in Japan, and a production procedure for PTP has been established at an acceptable cost. However, unknown problems and new needs with regard to safety among users of various age-groups still need to be examined. Considering accident reports involving children and older adults, the safety and quality of PTP and new forms of PTP, such as child-resistant and senior-friendly (CRSF) packaging, should be evaluated. We conducted an ergonomic study on children and older adults to compare types of commonly used PTP and new varieties of PTP. Opening tests were attempted by children and older adults using a common type of PTP (Type A) and child-resistant (CR) PTP (Types B1 and B2) made from soft aluminum foil. The same opening test was conducted on older patients with rheumatoid arthritis (RA). The results showed that CR PTP was difficult for children to open: only 1 out of 18 children could open Type B1. On the other hand, all eight of the older adults could open Type B1, and eight patients with RA could easily open Types B1 and B2. These findings suggest that the quality of CRSF PTP can be improved with the use of new materials.

Teaching L2 pragmatics to young learners

Abstract This paper reviews research on teaching pragmatics – and more specifically speech acts – to young L2 learners from two perspectives: (1) studies investigating young L2 learners’ pragmatic competence and (2) studies examining the potential of different materials with regard to pragmatics instruction. The review of L2 learners’ speech act competence addresses cross-sectional and longitudinal developmental studies, as well as studies that examined the effects of specific instructional approaches, learning contexts or materials on young L2 learners’ pragmatic competence. The review of studies examining materials addresses both studies focusing on designated L2 teaching materials produced for the explicit purpose of foreign language instruction of young learners, as well as studies examining speech acts included in children’s books. The paper concludes with a discussion of issues relevant to young learners and the teaching and researching of L2 pragmatics.

Poly(3,4‐Ethylene Dioxythiophene)/Poly(Styrene Sulfonate) Electrodes in Electrochemical Cells for Harvesting Waste Heat

Low‐grade waste heat is harvested using electrochemical cells. However, the high cost of commonly used platinum electrodes limits their application. Herein, poly(3,4‐ethylene dioxythiophene)/poly(styrene sulfonate) (PEDOT/PSS) films are reported as attractive alternatives to platinum electrodes, as they show a lower charge transfer resistance. Using ferricyanide/ferrocyanide as the electrolyte, the PEDOT/PSS‐based thermoelectrochemical cell with dimensions of 5 cm × 5 cm × 2 cm delivers a maximum power output of 300 μW with 1 Ω loading at a temperature difference of ≈30 K, which is sufficient for driving an array of light‐emitting diodes and Bluetooth humidity/temperature sensors for wireless communication. Furthermore, PEDOT/PSS offers the advantage of compatibility with insoluble redox couples such as Prussian blue analog materials, which facilitates determining the temperature‐dependent redox potential of different materials. The appropriate combination of redox couples enables realizing thermally regenerative electrochemical cells. Power can be generated during an environmental temperature change; however, the temperature difference between different electrodes need not be maintained for these cells.

PhyBaLCHT – Influence of indentation force on the results of cyclic hardness tests and investigations of comparability to uniaxial fatigue loading

Short-time procedures for determining the fatigue properties of materials can provide significant improvements in cost efficiency and are therefore of great scientific and industrial interest (Jost et al., 2017). A promising short-time procedure is PhyBaLCHT, which is based on cyclic indentation tests and can be used to determine the cyclic hardening potential of different materials at different conditions (Kramer et al., 2014; Bambach et al., 2016). In the present research work, this procedure was used to explore the cyclic hardening potential of 42CrMo4 steel (SAE 4140) in various heat treatment states as well as of 18CrNiMo7-6 steel variants with different chemical composition and heat treatments. A special focus of the investigation was the influence of maximum indentation force on the results determined with PhyBaLCHT. As expected, a higher dependency on local effects is seen at lower indentation forces. However, consistent values of cyclic hardening potential were determined down to low indentation forces, and indent diagonals below 5 µm. This gives perspective to describe e.g. gradients in material cyclic deformation behavior with high local resolution. Furthermore, the results of cyclic indentation tests were compared to the results of uniaxial cyclic compression tests, showing transferability of the cyclic indentation tests to the cyclic deformation behavior under uniaxial cyclic loading.

Potential of different materials for adsorption of micropollutants from wastewater

Potential of different materials for adsorption of micropollutants from wastewater

Potential of different materials for adsorption of micropollutants from wastewater

Potential of different materials for adsorption of micropollutants from wastewater

Development of a material with reproducible emission of selected volatile organic compounds – μ-Chamber study

Volatile organic compounds (VOCs) found indoors have the potential to affect human health. Typical sources include building materials, furnishings, cleaning agents, etc. To address this risk, chemical emission testing is used to assess the potential of different materials to pollute indoor air. One objective of the European Joint Research Project “MACPoll” (Metrology for Chemical Pollutants in Air) aims at developing and testing a reference material for the quality control of the emission testing procedure. Furthermore, it would enable comparison of measurement results between test laboratories. The heterogeneity of the majority of materials makes it difficult to find a suitable reference sample.In the present study, styrene, 2-ethyl-1-hexanol, N-methyl-α-pyrrolidone, lindane, n-hexadecane, 1,2-dimethyl- and 1,2-di-n-butyl-phthalate were added to 12 commercially available lacquers (6 alkyd and 6 acrylic polymer based lacquers) serving as carrier substrate. After homogenization, the mixtures were loaded into a Markes Micro-Chamber/Thermal Extractor (μ-CTE™) for curing and investigation of the emission behavior for each compound. For almost all of the investigated chemicals, the preferred glossy acrylic lacquer showed emissions that were reproducible with a variation of less than 20% RSD. Such lacquer systems have therefore been shown to be good candidates for use as reference materials in inter-laboratory studies.

Systematic Design Approach to the Development of High-Strength, Locally Adapted Structures with the Aid of the Finite Element Design (FED) Method

Design engineers can choose from a large variety of materials in order to fulfill a certain function. In those fields of application with a lower level of complexity, it is often sufficient to manufacture the entire component in a “monolithic” manner from one single material. Concurrent, partly contradictory and, most probably, local requirements that must be fulfilled by a component often make material selection more difficult. As a consequence, it is often necessary to use several different materials with a local and functional orientation, which is a part of the multi-material design strategy. The potential of different materials can be used most effectively if this information is made available to the design engineers as early on in the design process as possible. The aim of the SFB 675 sub-project C7, therefore, is the development of a systematic design approach (Finite Element Design, FED) that focuses on finite component elements. As a result, the potential of the optimization of local properties is taken into consideration, and the interaction between the materials, production processes, and design can all be described.

Comparison of the light‐weight potential of different materials used under bending loads

In transportation and many other technologies weight reduction brings about economical and environmental advantages. Therefore, materials are increasingly being judged according to their weight saving potential. In the case of structural materials, which have to withstand given stresses, a classification based on density alone (light metals) falls short, since the crucial parameter is the ratio between density and strength. In the case of parts loaded in bending the situation is complicated by the fact that e.g. the elastic stiffness of such parts (of a given length) does not only depend on their volume but also on their shape. It will be shown in this paper that the usual comparison of the weight saving potential of different materials under bending loads is strongly shape biased, favouring the more compliant material. An un‐biased comparison reveals, however, that e.g. the weight saving potential of high strength steels and aluminium alloys is comparable ‐ also if used for bending parts.

Correlation of Tests for Material Dustiness with Worker Exposure from the Bagging of Powders

Abstract A significant correlation was found between worker dust exposure from a bag packing operation and the results of two dustiness testers. The dustiness testers were the Heubach Dust Measurement Appliance and the Midwest Research Institute (MRI) Dustiness Tester. Both the Heubach and MRI dustiness tester predicted dust exposures to within an order of magnitude for the operation studied. The width of the prediction interval reflects typical variability in worker dust exposure measurements. Although the correlation between dustiness test results and dust exposures may be different for other operations, these results suggest that dustiness tests can be used to compare the relative potential of different materials to cause dust exposures. Heitbrink, W.A.; Todd, W.F.; Fischbach, T.J.: Correlation of Tests for Material Dustiness with Worker Exposure from the Bagging of Powders. Appl. Ind. Hyg. 4:12–16; 1989.

Quantification of smoke produced at fires. Test methods for smoke and methods of expressing smoke evolution

AbstractA limited review of the methods available for measuring smoke from burning materials has been carried out in order to define a method that could provide data for calculating smoke load. Results available in the literature have been expressed on a common basis and augmented by further experimental work carried out with a furnace similar to the National Bureau of Standards test furnace and a smoke‐containment volume (13.4m3) closer to that used by the Fire Research Station test. Encouraging agreement between the data have been found for methods which allow smoke to become diluted and to accumulate. Agreement could be improved if an allowance was made for flaming being extinguished at different times in a test, dependent on thermal stress and oxygen concentration, even when a pilot light is present. To help express the results clearly, a new unit for smokiness is proposed—the obscura (ob) defined as 1 ob=1 dB light attenuation per metre of light path. The smoke‐producing potential of different materials (Do) is then expressed in units of obscura—cubic metres per gram of volatiles produced during the fire condition (ob m3 g −1).