A review on the characterisation of natural fibres and their composites after alkali treatment and water absorption

Natural fibre-reinforced polymer matrix composites are gaining increased attention among the researchers due to their low density, biodegradability, abundance, good mechanical properties, etc. Significant amount of research works can be found on the material characterisation of natural fibres like hemp, flax, sisal, kenaf, coir and jute and their composites based on the polymer matrices. Natural fibres are hydrophilic in nature and exhibit poor interfacial adhesion between fibre and matrix. Modification of the fibre surface by chemical methods, such as alkalisation, benzoylation and acetylation, has been used by researchers to improve the above-mentioned shortcomings. This review paper focuses on the effect of alkali treatment on the material properties of various natural fibres and their composites along with their water absorption behaviour.     

Rejection of the maternal electrocardiogram in the electrohysterogram signal

The electrohysterogram (EHG) signal is mainly corrupted by the mother's electrocardiogram (ECG), which remains present despite analog filtering during acquisition. Wavelets are a powerful denoising tool and have already proved their efficiency on the EHG. In this paper, we propose a new method that employs the redundant wavelet packet transform. We first study wavelet packet coefficient histograms and propose an algorithm to automatically detect the histogram mode number. Using a new criterion, we compute a best basis adapted to the denoising. After EHG wavelet packet coefficient thresholding in the selected basis, the inverse transform is applied. The ECG seems to be very efficiently removed.     

An attractor regime for pulsed NMR in3He-B

We have found a new long-lived mode that can be generated in the regime of pulsed NMR in³He-B. The mode has a frequency different from both the Larmor one and that which was generated in the experiment of Corruccini and Osheroff by rf pulses longer than 104°. It does not correspond to stationary solutions of the Leggett-Takagi equations. The mode is due to the existence of an attractor that is a result of an interplay between nonlinear and dissipative effects in the spin dynamics of superfluid³He-B.     

关于杂化弦的共形反常(Ⅱ)

在对应于杂化弦的无限维 Kahler 流形的 DiffS′/S′和 Kahler 超流形 super-DillS′/S′上,存在两种类型的丛.一类是全纯矢量丛,它的 Ricci 曲率正好是杂化弦的 Virasoro 代数和超 Vira-soro 代数的反常中心项,另一类是复线丛,它可以被解释为该理论的鬼真空,它的曲率与临界维数时全纯矢量丛的曲率正好相差一个负号.本文用阶化 flay 流形的技术和几何量子代方法分别计算了这两类丛的 Ricci 曲率,杂弦反常相消的条件由这两类丛的乘积丛的 Ricci 曲率为零给出.这样,在临界维数我们就可以定义一个重参数不变的真空.     

A microfluidic vibrating wire viscometer for operation at high pressure and high temperature

This article discusses a microfluidic vibrating wire viscometer with an internal volume of a few microliters. Accuracy of order ±10% for viscosities ranging from 0.1 to 100 cP is demonstrated for temperatures (10 °C-175 °C) and pressures (10-24,000 psi) suitable for oilfield use by prior calibration in air and toluene. Comparison between multiple data sets indicates that a large fraction of the discrepancy between literature values is systematic, indicating that future refinements may be possible with better interpretation. Confinement effects are evaluated and are not found to play a significant role, which is surprising since the ratio (6.6) of the fluid channel width to the wire diameter is very low.     

RTG: a recursive realistic graph generator using random typing

We propose a new, recursive model to generate realistic graphs, evolving over time. Our model has the following properties: it is (a) flexible, capable of generating the cross product of weighted/unweighted, directed/undirected, uni/bipartite graphs; (b) realistic, giving graphs that obey eleven static and dynamic laws that real graphs follow (we formally prove that for several of the (power) laws and we estimate their exponents as a function of the model parameters); (c) parsimonious, requiring only four parameters. (d) fast, being linear on the number of edges; (e) simple, intuitively leading to the generation of macroscopic patterns. We empirically show that our model mimics two real-world graphs very well: Blognet (unipartite, undirected, unweighted) with 27 K nodes and 125 K edges; and Committee-to-Candidate campaign donations (bipartite, directed, weighted) with 23 K nodes and 880 K edges. We also show how to handle time so that edge/weight additions are bursty and self-similar.     

N=3的超共形代数的O(3)表示

本文用超场的语言从N=3的超共形理论的超空间形式中获得了N=3的超共形代数.建立了这个超共形代数的带有O(3)指标的基本超场表示——O(3)表示.发现此基本超场表示具有O(3)不变性.为了满足这个代数的封闭性,O(3)协变性和Jacobi恒等式,必须在理论中引入合适的群论项.基本超场按N=3的超空间费米坐标展开后,所得各分量共形场具有不同的共形权重.本文推导了这些分量共形场的算符乘积展开式(OPE),这些OPE包含了关于分量共形场的全部信息.最后,运用复围道积分方法,找到了这些分量共形场的变换规律.     

Sugar palm fiber/polyester nanocomposites: Influence of adding nanoclay fillers on thermal,dynamic mechanical,and physical properties

In this research, nanoclay used as filler in sugar palm‐reinforced composites was investigated by the physical, thermal, and dynamic mechanical properties. Various concentrations of nanoclay were used to fabricate composites by using hand lay‐up technique, followed by hot compression molding with naturally woven sugar palm fiber‐reinforced in polyester matrix. Among various weight concentrations such as 1–5% of nanoclay, it was found that 2% nanoclay‐filled composite (NC) demonstrated the best balance of thermomechanical properties and significantly enhanced the composite. DMA demonstrated that 2% nanoclay content resulted in improved viscoelastic behavior and higher glass transition temperature (T_g) of the composites. TGA also showed improvement in properties, whereas 3% nanoclay‐filled composite showed superior onset temperature, and 5% nanoclay‐filled composite exhibited highest remaining residue. The nanoclay filler was very effective to fill the porous structure and maintain the thickness stability. The thickness swelling was reduced with increasing amount of nanoclay in composites. Overall, the addition of nano clay improved thermal and physical properties of sugar palm‐reinforced polyester composite. J. VINYL ADDIT. TECHNOL., 26:236–243, 2020. © 2019 Society of Plastics Engineers     

Interacting with the Music Paint Machine: Relating the constructs of flow experience and presence

In this paper we report on the results of an experiment on the experience of flow and presence while engaging with an interactive music system, the Music Paint Machine. This music system provides a game-like environment in which a musician can create a digital painting by playing an acoustic musical instrument, by moving the body in different directions, and by selecting colours using a pressure mat. The experiment aimed at getting a better insight into the possible relationship between flow experience and presence. Based on the definition of flow as a combination of the highest level of presence (presence-as-feeling) and a positive emotional state (Riva et al., 2004a), we hypothesized that presence has a predictive value for flow. Sixty-five musicians, both amateur and professional, participated in the experiment. Flow experience was measured with the Flow State Scale (Jackson and Eklund, 2004). Presence was measured with an in-house designed presence questionnaire. Results showed a significantly strong correlation between flow and presence. Moreover, the scores for presence significantly predicted the Flow State Scale, and explained a significant proportion of variance in the Flow State Scale. Furthermore, many significant associations were found between flow and presence variables, among which the most significant were the strong correlation (Spearman’s rank) between the naturalness of using the system and the Flow State Scale and between the feeling of non-mediation and the Flow State Scale.     

Simulations of Noise in Phase-Separated Transition-Edge Sensors for SuperCDMS

We briefly review a simple model of superconducting-normal phase-separation in transition-edge sensors (TESs) in the SuperCDMS experiment. After discussing some design considerations relevant to the TESs in the experiment, we study noise sources in both the phase-separated and phase-uniform cases. Such simulations will be valuable for optimizing the critical temperature and TES length of future SuperCDMS detectors.