Oscillating pressure sintered W-Cu refractory alloy with high density and hardness under lower temperature

To derive P,N-doped cellulose fibrils, phosphoric acid and aqueous ammonia were placed in a one-pot reaction, and the phosphate groups and ammonium phosphates were successfully introduced into the cellulose surface. The obtained P,N-doped cellulose fibrils with high liberation were thereafter incorporated into a high-density polyethylene (HDPE) matrix to improve the flame retardancy of HDPE composites, and they had a significant improvement on flame retardancy of HDPE composites. In particular, 7 wt % P,N-doped cellulose fibrils considerably reduced the average and peak heat release rate (HRR) by 29.6% and 72.9%, respectively, and increased the limited oxygen index (LOI) by 30.5%. The presence of phosphate groups and ammonium phosphates within P,N-doped cellulose fibrils was found to promote the thermal degradation of HDPE composites at a lower temperature (i.e., 240 °C). The released acid catalyzed the dehydration of cellulose to form an aromatic carbonaceous structure with a higher crystalline orientation, which improves the flame retardancy of HDPE composites.

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CLASSIFYING AND MAPPING OF VEGETATED AREA IN AL- BAHA REGION, SAUDI ARABIA USING REMOTE SENSING. II. THE RELATIONSHIP BETWEEN ELEVATION, LAND SURFACE DAY TEMPERATURE, AND VEGETATION DENSITY.

10.36106/ijar/7616476 ◽

2020 ◽

pp. 81-84

Author(s):

Abdullah Saleh Al-Ghamdi

Keyword(s):

Remote Sensing ◽

Saudi Arabia ◽

Land Surface ◽

Eastern Desert ◽

High Density ◽

Vegetation Density ◽

Central Belt ◽

The North ◽

North Eastern ◽

Lower Temperature

Classifying and mapping of vegetated area in Al- Baha region, Saudi Arabia using remote sensing shows that the medium-high density vegetation is mostly found at the central part of Al-Baha region separating the highlands and the low lands. Results obtained show that only 862.5 km2 (7.7%) Al-Baha region is covered with medium-high density vegetation found mainly at the 6-15km width horizontal central belt (at districts of Al-Mandaq, Al-Baha and south Baljurashi) along high foggy mountainous plateau. Whereas, about 65% of Al-Baha region has very low-none density vegetation mainly occurred extensively at Tihama low plain towards the Red Sea and at the north-eastern desert plain. In addition, study reveals that the highlands of Al-Baha have the most numbers of trees represents the areas of the highest elevations in the region (range between 1940 and 2366 m above sea level. This indicates that there is relationship between this elevation range with medium to high vegetation density. Similarly, the low surface temperatures are mainly located at the central belt across Al-Baha region. When overlaid with medium-high vegetation density zone with the temperature map, it was visually observed that it almost fit with lower temperature zone of less than 15°C. This also indicates that there is relationship between lower temperature with medium-high vegetation density.

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Accelerated sintering and phase transformation of TiO2in microwave radiation

Journal of Materials Research ◽

10.1557/jmr.1998.0465 ◽

1998 ◽

Vol 13 (12) ◽

pp. 3417-3422 ◽

Cited By ~ 17

Author(s):

Zhi-Peng Xie ◽

Xu-Dong Fan ◽

Yong Huang

Keyword(s):

Phase Transformation ◽

Microwave Radiation ◽

Dwell Time ◽

High Density ◽

Sintering Process ◽

Grain Sizes ◽

Refined Microstructure ◽

Lower Temperature ◽

Powder Compacts ◽

Heating Behavior

The sintering process and phase transformation of submicrometer powder compacts of TiO2 were investigated using 2.45 GHz microwave radiation. The microwave-sintered samples were densified more rapidly and at much shorter time and lower temperature than that of the conventionally sintered samples. Also, an accelerated phase transformation from anatase to rutile was observed in microwave processing when the dwell time is cut down from 6 h in conventional to 30 min in microwave at 1000 °C. The samples sintered in microwave show a refined microstructure and smaller grain sizes at high density near 98–99% theoretical. In addition, the reasons for rapidly heating behavior and enhanced sintering on TiO2 in microwave are discussed.

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Effects of POE and Carbon Black on the PTC Performance and Flexibility of High-Density Polyethylene Composites

Advances in Polymer Technology ◽

10.1155/2021/1124981 ◽

2021 ◽

Vol 2021 ◽

pp. 1-11

Author(s):

Feng Xue ◽

Kangcai Li ◽

Lei Cai ◽

Enyong Ding

Keyword(s):

Carbon Black ◽

High Density Polyethylene ◽

Crystallization Behavior ◽

Thermoplastic Elastomer ◽

Positive Temperature Coefficient ◽

High Density ◽

Room Temperature Resistivity ◽

Positive Temperature ◽

Lower Temperature ◽

Micro Morphology

High-density polyethylene (HDPE)/carbon black (CB) is widely used in positive temperature coefficient (PTC) composites. In order to expand its applications to fields that need good flexibility, polyolefin elastomer (POE) was incorporated into HDPE/CB composites as a secondary thermoplastic elastomer phase to provide flexibility. The effects of POE and CB content on the PTC performance and flexibility were investigated. Micro morphology and crystallization behavior are closely related to PTC properties. SEM was conducted to reveal phase morphology and filler dispersion, and DSC was conducted to research crystallization behavior. The results show that the incorporation of 18 wt.% POE can decrease the percolation threshold of conductive carbon black from 22.5 wt.% to 16 wt.%. When the CB content is 30 wt.%, the room temperature resistivity gradually increases with the increasing content of POE because of the barrier effect of POE phase, and the PTC intensity is gradually enhanced. Meanwhile, the PTC switching temperature shifts down to a lower temperature. The incorporation of 18 wt.% POE significantly increases the elongation at break, reaching an ultrahigh value of 980 wt.%, which means great flexibility has been achieved in HDPE/POE/CB composites. This work provides a new method of fabricating PTC composites with balanced electrical and mechanical properties.

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Origin of High Q for Microwave Complex Perovskite

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.421-422.77 ◽

2009 ◽

Vol 421-422 ◽

pp. 77-80 ◽

Cited By ~ 8

Author(s):

Hitoshi Ohsato ◽

Eiichi Koga ◽

Isao Kagomiya ◽

Kenichi Kakimoto

Keyword(s):

High Density ◽

Order Structure ◽

High Symmetry ◽

Complex Perovskite ◽

High Q ◽

Sintering Time ◽

Plasma Sintering ◽

Spark Plasma ◽

Lower Temperature ◽

Q Values

Origins of high Q are considered on intrinsic as high symmetry, ordering structure and high density crystal structure. It was concluded that the high symmetry brings high Q instead of ordering comparing some cases as follows: As if ordering ratio of Ba(Zn1/3Ta2/3)O3 (BZT) is high of about 80%, Q values are distributed from low to high Q. Disordered BZT ceramics with high density obtained for short sintering time by spark plasma sintering (SPS) showed high Q. Ba(Zn1/3Nb2/3)O3 (BZN) with order-disorder transition showed high Q at disorder form sintered over the transition temperature. And, the disordered BZN with high Q annealed at lower temperature changed to order structure without improvement of Q.

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Planar defects in ordered (Ga,In)P

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100106570 ◽

1988 ◽

Vol 46 ◽

pp. 902-903

Author(s):

S. McKernan ◽

C. B. Carter ◽

D. Bour ◽

J. R. Shealy

Keyword(s):

Electron Diffraction ◽

Vapor Phase ◽

Growth Direction ◽

High Density ◽

Ordered Structure ◽

Planar Defects ◽

Diffraction Patterns ◽

Ternary Semiconductors ◽

Anion Species ◽

Metallic Vapor

The growth of ternary III-V semiconductors by organo-metallic vapor phase epitaxy (OMVPE) is widely practiced. It has been generally assumed that the resulting structure is the same as that of the corresponding binary semiconductors, but with the two different cation or anion species randomly distributed on their appropriate sublattice sites. Recently several different ternary semiconductors including AlxGa1-xAs, Gaxln-1-xAs and Gaxln1-xP1-6 have been observed in ordered states. A common feature of these ordered compounds is that they contain a relatively high density of defects. This is evident in electron diffraction patterns from these materials where streaks, which are typically parallel to the growth direction, are associated with the extra reflections arising from the ordering. However, where the (Ga,ln)P epilayer is reasonably well ordered the streaking is extremely faint, and the intensity of the ordered spot at 1/2(111) is much greater than that at 1/2(111). In these cases it is possible to image relatively clearly many of the defects found in the ordered structure.

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Silicon Tetrachloride Synthesis from Rice Hulls: Transmission and Scanning Electron Microscope Study

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100094437 ◽

1972 ◽

Vol 30 ◽

pp. 236-237 ◽

Cited By ~ 1

Author(s):

Richard S. Thomas ◽

Prabir K. Basu ◽

Francis T. Jones

Keyword(s):

Silicon Tetrachloride ◽

Silica Sand ◽

Mineral Matter ◽

Chemical Heterogeneity ◽

Scanning Electron Microscope Study ◽

Rice Hulls ◽

Hull Structure ◽

Lower Temperature ◽

Image Position ◽

Disposal Problem

Silicon tetrachloride, used in industry for the production of highest purity silicon and silica, is customarily manufactured from silica-sand and charcoal.SiCl4 can also be made from rice hulls, which contain up to 20 percent silica and only traces of other mineral matter. Hulls, after carbonization, actually prove superior as a starting material since they react at lower temperature. This use of rice hulls may offer a new, profitable solution for a rice mill byproduct disposal problem.In studies of the reaction kinetics with carbonized hulls, conversion of SiO2 to SiCl4 was found to proceed within a few minutes to a constant, limited yield which depended reproducibly on the ambient temperature of the reactor. See Fig. 1. This suggested that physical or chemical heterogeneity of the silica in the hull structure might be involved.

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Quantitative defect studies in semiconductor TEM samples prepared by low angle ion milling

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100138932 ◽

1995 ◽

Vol 53 ◽

pp. 512-513

Author(s):

L. Mulestagno ◽

J.C. Holzer ◽

P. Fraundorf

Keyword(s):

Sample Preparation ◽

Milling Time ◽

High Density ◽

Low Density ◽

Ion Milling ◽

High Quality ◽

Variable Angle ◽

Major Disadvantage ◽

Induced Defects

Due to the wealth of information, both analytical and structural that can be obtained from it TEM always has been a favorite tool for the analysis of process-induced defects in semiconductor wafers. The only major disadvantage has always been, that the volume under study in the TEM is relatively small, making it difficult to locate low density defects, and sample preparation is a somewhat lengthy procedure. This problem has been somewhat alleviated by the availability of efficient low angle milling.Using a PIPS® variable angle ion -mill, manufactured by Gatan, we have been consistently obtaining planar specimens with a high quality thin area in excess of 5 × 104 μm2 in about half an hour (milling time), which has made it possible to locate defects at lower densities, or, for defects of relatively high density, obtain information which is statistically more significant (table 1).

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Using the scanning electron microscope for failure analysis of high density magnetic media

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100126755 ◽

1987 ◽

Vol 45 ◽

pp. 392-393

Author(s):

Evelyn R. Ackerman ◽

Gary D. Burnett

Keyword(s):

Electron Microscope ◽

Scanning Electron Microscope ◽

Failure Analysis ◽

High Density ◽

Magnetic Media ◽

Specific Data ◽

Retrieval Systems ◽

Operating Environments ◽

The Media ◽

Scanning Electron

Advancements in state of the art high density Head/Disk retrieval systems has increased the demand for sophisticated failure analysis methods. From 1968 to 1974 the emphasis was on the number of tracks per inch. (TPI) ranging from 100 to 400 as summarized in Table 1. This emphasis shifted with the increase in densities to include the number of bits per inch (BPI). A bit is formed by magnetizing the Fe203 particles of the media in one direction and allowing magnetic heads to recognize specific data patterns. From 1977 to 1986 the tracks per inch increased from 470 to 1400 corresponding to an increase from 6300 to 10,800 bits per inch respectively. Due to the reduction in the bit and track sizes, build and operating environments of systems have become critical factors in media reliability.Using the Ferrofluid pattern developing technique, the scanning electron microscope can be a valuable diagnostic tool in the examination of failure sites on disks.

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