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Additive manufacturing of fabrics is an emerging research topic with potential applications in several industries including high performance wearable products and high-temperature textiles. Therefore, thermal, mechanical, and viscoelastic properties of such fabrics need to be determined. In this research, the thermomechanical behavior of additively manufactured plain weave fabrics at and above glass transition temperature ([T.sub.g]) is studied. The time-dependent mechanical response using a viscoelastic material model is represented by a Prony series as a function of frequency (f). Unit cells of plain weave fabrics are additively manufactured using poly(lactic) acid (PLA). Tensile and compression tests were performed on unit cells in a thermal environment using dynamic mechanical analysis (DMA). A multiphysics finite element model is implemented to duplicate the experimental setup. The experimental results are compared with that of computational results. The relative error percentages in the peak forces at each temperature are 23.60% at 60[degrees]C, -8.85% at 65[degrees]C, and -6.25% at 70[degrees]C. A better agreement in peak forces is seen for unit cells above [T.sub.g]. The computational model developed for unit cells is used to predict the thermomechanical-viscoelastic response of large additively manufactured fabric structures which is difficult to evaluate experimentally. KEYWORDS 3D printed textile, additive manufacturing, multiphysics finite element modeling, simulation, 1 | INTRODUCTION A wide variety of methods have been used to manufacture fabrics with high strength, high flexibility and good tear resistance. [1,2] Depending on the method adopted, a [...]

Bronze Age agro-pastoralist populations with economies and materials that are generally consistent with the Andronovo Culture--but with localised variations--are known throughout the mountains bordering the Eastern Eurasian Steppe. Recently, evidence for this tradition has also been found in north-west Xinjiang, China, although many questions remain about the production, use and significance of ceramics here. The authors' analyses of a sample of pottery from sites across the Bortala Valley permit the reconstruction of the ceramic chaine operatoire and offer two distinct stories: one of cultural connectivity with regional networks of Eurasian pastoralists, and another about self-expression through small-scale local ceramic production. Keywords: China, Xinjiang, Bronze Age, Andronovo, ceramics, chaine operatoire, Introduction Situated between the vast Eurasian Steppe, the Inner Asian Mountain Corridor and central China, Xinjiang was a central node in ancient trans-Eurasian exchanges. While best known for the historic-period [...]

The Dzungar Basin of northern Xinjiang has previously been considered a marginal environment with little evidence for the development of prehistoric agriculture. Recent archaeobotanical studies have indicated the region as being a route for the transmission of domesticated plants, technologies and ideas between East and West Eurasia during prehistory, as early as 5000 BP. These interactions are still poorly understood and most evidence for early plant food production and consumption in the region comes from limited mortuary contexts. In this study we present plant macrofossil analysis from the settlement site of Luanzagangzi on the southern side of the Dzungar Basin. From ca. 3130 BP an agricultural package of east and west Asian cereals and chaff is present, comprising wheat, barley, foxtail millet, broomcorn millet, and significantly a single grain of japonica type rice. AMS dating indicates this is the oldest directly dated rice in Xinjiang and the broader region, ranging 3069–2881 cal. BP. Cereal morphometrics and material culture from the site further indicate a connection with the Gansu region to the east. The spread of agriculture into the site environment may be linked to the onset of wetter conditions relating to strengthened westerly systems across arid Central Asia in the Late-Holocene. A declining abundance of West Asian cultivars over the period of the site's occupation possibly reflect a shift away from intensive agriculture to low-level management of millets. [ABSTRACT FROM AUTHOR]

Bronze Age social and cultural interconnections across the Eurasian steppe are the subject of much current debate. A particularly significant place is occupied by the Andronovo Culture or family of cultures. Important new data document the most easterly extension of Eurasian Bronze Age sites of Andronovo affinity into western China. Findings from the site of Adunqiaolu in Xinjiang and a new series of radiocarbon dates challenge existing models of eastward cultural dispersion, and demonstrate the need to reconsider the older chronologies and migration theories. The site is well preserved and offers robust potential for deeper study of the Andronovo culture complex, particularly in the eastern mountain regions. Keywords: China, Eurasian steppe, Bronze Age, Andronovo, chronology, Introduction The Bronze Age of the Eurasian steppe, broadly associated with mobile or semi-mobile communities, can be seen as diverse in terms of material culture, architecture and burial practices. Following [...]

The mechanisms of the origin and dispersal of millet agriculture in northern China are poorly understood. We used plant macroremains, stable isotope compositions of human bone collagen, and pollen records from the Sitai site to reconstruct changes in subsistence strategies and their relationship with the ecological environment from the early to middle Holocene on the Inner Mongolian Plateau in northern China. Charred weed-like seeds, the bones of small mammals, eggshell fragments, together with microliths, indicate the practice of hunter-gatherer subsistence strategies during 10,500–10,200 cal yr BP. Deciduous broadleaved forest-steppe vegetation was present around the Sitai site during the early middle Holocene (8000–7000 cal yr BP). Additionally, isotopic compositions of human bones and plant remains reveal that millet agriculture and hunting-gathering appeared in the early middle Holocene. The spread of millet agriculture on the Inner Mongolian Plateau was likely favored by an increase in precipitation between 8000 and 7000 cal yr BP. The development of millet agriculture on the Inner Mongolia Plateau and the Loess Plateau was the prelude to its subsequent spread to the Tibet Plateau. [ABSTRACT FROM AUTHOR]

The relationships between societal and environmental changes have long attracted strong interest amongst scientists. Each of these systems has their own internal dynamics such as the adaptability and social systems built by people; and the feedbacks and controls on environmental systems. North west Xinjiang presents a challenging topographic and climate setting for people. Yet existing evidence shows Bronze Age populations settled into the Bortala Valley as early as the third millennium BCE. The harshness of the region provides a test case for exploring how environmental changes and societal changes may have intertwined. Near the town of Wenquan there is an extensive wetland which contains a sedimentary record covering the last 10,400 years. The early to mid-Holocene is marked by desert and a lake at Wenquan, but there is little evidence for human activity. By 4500 cal year BP the climate became more humid and soon peak humidity occurred when a regional steppe was developed and small numbers of trees were present on the mountains, also the lake shallowed to become a marsh and peatland. The uplands saw a slight increase in tree cover after this, probably as a result of moisture increase due to some cooling. Later changes in the archaeological record seem to be independent of the timing of any environmental changes, and human impacts on the wetland were small until historical times. In short, the major change from desert to steppe may have enabled people to settle the region, but later changes in the environment were too small to be revealed in the Wenquan sediment data, with the adaptability of societies overcoming any environmental challenges and with land-use practices being too small or localized to impact the palaeoenvironmental record. [ABSTRACT FROM AUTHOR]

The objective of this work is to model and quantify the layer-wise spatial evolution of porosity in parts made using Additive Manufacturing (AM) processes. This is an important research area because porosity has a direct impact on the functional integrity of AM parts such as their fatigue life and strength. To realize this objective, an Augmented Layer-wise Spatial log Gaussian Cox process (ALS-LGCP) model is proposed. The ALS-LGCP approach quantifies the spatial distribution of pores within each layer of the AM part and tracks their sequential evolution across layers. Capturing the layer-wise spatial behavior of porosity leads to a deeper understanding of where (at what location), when (at which layer), and to what severity (size and number) pores are formed. This work therefore provides a mathematical framework for identifying specific pore-prone areas in an AM part, and tracking the evolution of porosity in AM parts in a layer-wise manner. This knowledge is essential for initiating remedial corrective actions to avoid porosity in future parts, e.g., by changing the process parameters or part design. The ALS-LGCP approach proposed herein is a significant improvement over the current scalar metric used to quantify porosity, namely, the percentage porosity relative to the bulk part volume. In this article, the ALS-LGCP approach is tested for metal parts made using a binder jetting AM process to model the layer-wise spatial behavior of porosity. Based on offline, non-destructive X-Ray computed tomography (XCT) scan data of the part the approach identifies those areas with high risk of porosity with statistical fidelity approaching 85% (F-score). While the proposed work uses offline XCT data, it takes the critical first-step from a data analytics perspective for taking advantage of the recently reported breakthroughs in online, in-situ X-Ray-based monitoring of AM processes. Further, the ALS-LGCP approach is readily extensible for porosity analysis in other AM processes; our future forays will focus on improving the computational tractability of the approach for online monitoring. [ABSTRACT FROM AUTHOR]

Based on identification of fossil charcoals from 11 sites in the Hexi Corridor, we reconstruct the local vegetation community and human impact on it in the period from 4300 to 2400 cal. yr BP. More than 20 broadleaved taxa and 4 coniferous trees are present. The charcoal identifications show that vegetation in the period 4300–2400 cal. yr BP differed regionally because of variations in local topography and water supply, with limited diversity in the northwest Hexi Corridor and relatively rich diversity in the southeast area. In the northwest Hexi Corridor, the oasis woodland consisted mainly of Tamarix sp., Salix sp., and Populus sp. In the southeast region, the vegetation was a mix of coniferous forest and broadleaf woodland. By comparison with modern patterns of vegetation, broadleaf trees were much more abundant and the spruce forest extended down to relatively low altitudes, suggesting greater vegetation cover and richer diversity than today. There was also temporal variation. In the period from 4300 to 4000 cal. yr BP, woodland was relatively scarce, while the greatest diversity of plants appears in the period from 4000 to 3500 cal. yr BP, probably because of better moisture conditions at that time. After 3500 cal. yr BP, there was the appearance of woodland dominated by Morus alba, suggesting that cultivated trees may have played a key role in the lives of local people. [ABSTRACT FROM AUTHOR]