6,065 research outputs found
A note on a characterization theorem for a certain class of domains
We have introduced and studied in [3] the class of Globalized
multiplicatively pinched-Dedekind domains (GMPD domains). This class of domains
could be characterized by a certain factorization property of the
non-invertible ideals, (see [3, Theorem 4]). In this note a simplification of
the characterization theorem [3, Theorem 4] is provided in more general form
Physical and acoustic properties of petroleum and renewable based polyurethane foam filled with shorea leprosula
Physical and acoustic properties of petroleum-based polyurethane (PU) and renewable based polyurethane (RPU) foam composites filled with Shorea Leprosula (Red Meranti) fiber filler has been investigated. Shorea Leprosula wood dust namely as SL was used as the filler. RPU was used with hope to substitute the current polyurethane. This research was carried out to investigate the physical and acoustical properties and the ability of polymer foam composites (PF) towards sound absorption coefficient (SAC) based on the wood fiber size with range of 150-200 μm (powder), 250-300 μm (fibrous) and 900-1000 μm (flakes). 5 wt%, 10 wt%, 15 wt% and 20 wt% of SL filler content and thickness of 10 mm, 20 mm and 30 mm were used for each PF sample. PF samples have been tested by using Impedance Tube test, Scanning Electron Microscopy (SEM) and Mettler Toledo Density kit. As a result, the sound absorption coefficient (SAC) shows value at achievable frequency range at low (0-1500 Hz) and high (1501-6000 Hz) frequency absorption level. PU with powder fiber size (UP20), average pore size with 425.4 μm (smallest), and density 857.9 kg/m3 (highest) shows better sound behaviour with SAC value of 0.2478 and 0.9598 at low and high frequency absorption level. Meanwhile, for RPU with powder fiber size (RP20), average pore size with 479.8 μm (smallest), and density 839.0 kg/m3 (highest) shows better sound behaviour with SAC value of 0.2478 and 0.9940 at low frequency and high frequency absorption level. Moreover, UP20 and RP20 give the highest SAC value with 30 mm in thickness 0.9037 and 0.9909, and 0.9784 and 0.9809 at low and high frequency absorption level respectively. In conclusion, acoustical characteristics of PF samples shows the ability to influence the absorption coefficient of polymeric foam at different frequency levels. Both type of PF produce is suitable for sound absorbing materials for indoor and outdoor sound applications
The Saint and the Sultan: The Crusades, Islam and Francis of Assisi’s Mission of Peace
The Saint and the Sultan: The Crusades, Islam and Francis of Assisi’s Mission of Peace Paul Moses New York: Doubleday, 200
Graph Based Semi-supervised Learning with Convolution Neural Networks to Classify Crisis Related Tweets
During time-critical situations such as natural disasters, rapid
classification of data posted on social networks by affected people is useful
for humanitarian organizations to gain situational awareness and to plan
response efforts. However, the scarcity of labeled data in the early hours of a
crisis hinders machine learning tasks thus delays crisis response. In this
work, we propose to use an inductive semi-supervised technique to utilize
unlabeled data, which is often abundant at the onset of a crisis event, along
with fewer labeled data. Specif- ically, we adopt a graph-based deep learning
framework to learn an inductive semi-supervised model. We use two real-world
crisis datasets from Twitter to evaluate the proposed approach. Our results
show significant improvements using unlabeled data as compared to only using
labeled data.Comment: 5 pages. arXiv admin note: substantial text overlap with
arXiv:1805.0515
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