1,302 research outputs found
Affine actions on non-archimedean trees
We initiate the study of affine actions of groups on -trees for a
general ordered abelian group ; these are actions by dilations rather
than isometries. This gives a common generalisation of isometric action on a
-tree, and affine action on an -tree as studied by I. Liousse. The
duality between based length functions and actions on -trees is
generalised to this setting. We are led to consider a new class of groups:
those that admit a free affine action on a -tree for some .
Examples of such groups are presented, including soluble Baumslag-Solitar
groups and the discrete Heisenberg group.Comment: 27 pages. Section 1.4 expanded, typos corrected from previous versio
X-ray Imaging of Transplanar Liquid Transport Mechanisms in Single Layer Textiles
Understanding the
penetration of liquids within textile fibers
is critical for the development of next-generation smart textiles.
Despite substantial research on liquid penetration in the plane of
the textile, little is known about how the liquid penetrates in the
thickness direction. Here we report a time-resolved high-resolution
X-ray measurement of the motion of the liquid–air interface
within a single layer textile, as the liquid is transported across
the textile thickness following the deposition of a droplet. The measurement
of the time-dependent position of the liquid meniscus is made possible
by the use of ultrahigh viscosity liquids (dynamic viscosity from
10<sup>5</sup> to 2.5 Ă— 10<sup>6</sup>Â times larger than
water). This approach enables imaging due to the slow penetration
kinetics. Imaging results suggest a three-stage penetration process
with each stage being associated with one of the three types of capillary
channels existing in the textile geometry, providing insights into
the effect of the textile structure on the path of the three-dimensional
liquid meniscus. One dimensional kinetics studies show that our data
for the transplanar penetration depth Δ<i>x</i><sub>L</sub> vs time do not conform to a power law, and that the measured
rate of penetration for long times is smaller than that predicted
by Lucas–Washburn kinetics, challenging commonly held assumptions
regarding the validity of power laws when applied to relatively thin
textiles
C1q acts in the tumour microenvironment as a cancer-promoting factor independently of complement activation
Complement C1q is the activator of the classical pathway. However, it is now recognized that C1q can exert functions unrelated to complement activation. Here we show that C1q, but not C4, is expressed in the stroma and vascular endothelium of several human malignant tumours. Compared with wild-type (WT) or C3- or C5-deficient mice, C1q-deficient (C1qa(-/-)) mice bearing a syngeneic B16 melanoma exhibit a slower tumour growth and prolonged survival. This effect is not attributable to differences in the tumour-infiltrating immune cells. Tumours developing in WT mice display early deposition of C1q, higher vascular density and an increase in the number of lung metastases compared with C1qa(-/-) mice. Bone marrow (BM) chimeras between C1qa(-/-) and WT mice identify non-BM-derived cells as the main local source of C1q that can promote cancer cell adhesion, migration and proliferation. Together these findings support a role for locally synthesized C1q in promoting tumour growth
Nonlinear dynamic analysis of gas turbine combustor leaf seal
The leaf seals are one of the typical sealing systems in gas turbine and jet engines. In Baker Hughes LT family gas turbines, they are used to create sealing between the combustion chamber and the first stage nozzle. The leaf seals are thin metallic plates and subjected to dynamic loads and high temperatures. They have curved contacts, and depending on the inclination, they can experience partial contact. Furthermore, when excited by dynamic loads, the leaf seal can be subject to intermittent contact, possibly triggering wear out or vibratory phenomena. Due to its flexibility and its partial seating, it exhibits a complex nonlinear dynamic behaviour, strongly variable with the operating conditions. This study presents a numerical investigation using coupled static/dynamic harmonic balance method (HBM) frequency-based solution technique. The reported solutions include nonlinear forced response and contact studies for various operating and kinematic conditions along with brief insights
Towards biological control strategies for the bronze bug, Thaumastocoris peregrinus, on eucalyptus plantations in South America.
Edição dos abstracts do 24º IUFRO World Congress, 2014, Salt Lake City. Sustaining forests, sustaining people: the role of research
MPC Approach for Synchronized Supply Chains of Perishable Goods
Trabalho apresentado em 7th International Conference on Industrial Engineering and Systems Management (IESM’17), 2017,Saarbrucken, GermanyThe movement of perishable goods is growing
worldwide. Perishable goods need to be available to the market
before the expiration date. With the decrease in inventory levels
the components of a supply chain become even more integrated
and dependent on coordinated decisions. Information regarding
perishable goods must be visible throughout the supply chain for
avoiding goods loss. A Model Predictive Control (MPC) heuristic
to address operations management at supply chains of perishable
goods is proposed in this paper. The approach is capable to
follow the remaining time until expiration date which is critical
to avoid losses. The supply chain is modeled using a state-space
representation and operations management at the supply chain is
formulated as an MPC Problem. In order to cope with operational
decisions, the problem is solved on a periodic basis. The proposed
approach is capable to deal with production decisions, monitor
work-in-progress (WIP), and make transport assignments while
monitoring the remaining time until the expiration date. Flows
over the supply chain can be synchronized and therefore we
named this type of supply chain a Synchronized Supply Chain
(SSC). The approach is modular and easily scalable for largescale
supply chains. Numerical results illustrate these statements.info:eu-repo/semantics/publishedVersio
Profile of digital literacy of mathematics education students in online learning and its relationship with learning motivation
This study aims to determine the digital literacy profile of Mathematics Education students at Universitas Negeri Makassar in online learning and its relationship with learning motivation. The research was designed with a quantitative approach ex-post facto model with the main method of survey. The research was conducted on Mathematics Education students at Universitas Negeri Makassar. Based on the results and discussion, it can be concluded that (1) mathematics education students have a high level of digital literacy, (2) mathematics education students have a high level of learning motivation, and (3) the relationship between digital literacy and learning motivation has a linear relationship
Quantitative MRI Measurement of Binder Distributions in Green-State Ceramics
Development of reliable and improved structural ceramics for advanced heat engines and other applications requires process diagnostics and materials evaluation from powder preparation to green-body forming to final sintering. Injection molding is a promising processing method being developed for mass production of complex-shaped heat engine components such as turbochargers (rotors and stator vanes) and engine valves. Major processing steps in injection-molded ceramic manufacturing include preparation of ceramic powders and organic binders, mixing, molding, binder removal, sintering, and finishing [1]. While materials evaluation and diagnostics are needed throughout the process, it is particularly important to evaluate the distributions of binders/plasticizers in as-molded green bodies [2]. Poor distribution of these organics in a green body can lead to a final part that is defective or that has poor mechanical properties after it is sintered
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