Analysis of the Fragmentation of AlON and Spinel Under Ballistic Impact

2013 ◽  
Vol 80 (3) ◽  
Author(s):  
Elmar Strassburger ◽  
Martin Hunzinger ◽  
Parimal Patel ◽  
James W. McCauley
Keyword(s):  
High Speed ◽  
Fragment Size ◽  
Complete Recovery ◽  
Light Sheet ◽  
Ballistic Resistance ◽  
Fine Grained ◽  
Fine Grain ◽  
Significant Difference ◽  
Fragment Formation ◽  
Visualization Techniques

It has been demonstrated that significant weight reductions can be achieved, compared to conventional glass-based armor, when a transparent ceramic is used as the strike face on a glass-polymer laminate. Magnesium aluminate spinel (MgAl2O4) and AlON are promising candidate materials for application as a hard front layer in transparent armor. Comprehensive, systematic investigations of the fragmentation of ceramics have shown that the mode of fragmentation is one of the key parameters influencing the ballistic resistance of ceramics. In the study described here, the fragmentation of AlON and three types of spinel was analyzed: two types of fine grained spinel with nominal average grain sizes 0.6 μm and 1.6 μm and a bimodal grain-sized spinel with large grains of 250 μm size in a fine grain (5–20 μm) matrix were examined. The ceramic specimens of 6-mm thickness were glued to an aluminum backing and impacted with armor piercing (AP) projectiles of caliber 7.62 mm at two different velocities—850 m/s and 1100 m/s. The targets were integrated into a target box, which allowed for an almost complete recovery and analysis of the ceramic fragments. Different types of high-speed cameras were applied in order to visualize the different phases of fragment formation and ejection. A laser light-sheet illumination technique was applied in combination with high-speed cameras in order to determine size and speed of ejected ceramic fragments during projectile penetration. The application of the visualization techniques allowed for the analysis of the dynamics of the fragment formation and interaction with the projectile. A significant difference in the fragment size distributions of bimodal grain-sized spinel and AlON was observed.

Effect of Fill Size on the Stability of Barrier Dams

2011 ◽  
Vol 90-93 ◽  
pp. 1373-1382 ◽  
Author(s):  
Zhen Ming Shi ◽  
You Quan Wang ◽  
Jian Feng Chen ◽  
Zu Guang Shang ◽  
Xiao Tao He
Keyword(s):  
Debris Flow ◽  
Failure Mode ◽  
High Speed ◽  
Failure Time ◽  
Coarse Grain ◽  
Fine Grained ◽  
Fine Grain ◽  
Earth Pressures ◽  
Coarse Grains ◽  
The Stability

The fills of barrier dams commonly result from high-speed landslides debris flow. In this paper, four model tests were conducted to study the effect of fill size on the stability of barrier dams. The failure time, failure mode, pore pressures and earth pressures were then observed and analyzed. The results show that barrier dams composed of coarse-grains or well-graded fills are more stable than those composed of fine-grained fills; coarse-grain-dams are more sensitive to the rising of water level than fine-grain-dams; the failure mode of coarse-grain-dams is usually overflowing-erosion and the barrier dams usually fail from the top of dams; the failure mode of fine-grain-dams is sliding and the barrier dams fail initially from the slope downstream.

Effect of Fine Grain on Mechanical Properties of A6N01 Alloy

2013 ◽  
Vol 753 ◽  
pp. 501-504 ◽  
Author(s):  
Hiroaki Kusuhara ◽  
Munetoshi Noguchi ◽  
Masafumi Noda ◽  
Hisashi Mori ◽  
Kunio Funami
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Speed ◽  
Al Alloy ◽  
Proof Stress ◽  
Fine Grained ◽  
Fine Grain ◽  
Heat Treated ◽  
Fine Grained Structure

The good formability and corrosion resistance of 6N01 Al alloy allow it to be utilized in high-speed train systems, and weight reduction of railway vehicles is possible by improving the strength of this alloy. This study examined the effect of the fine-grained structure on the mechanical properties of the alloy formed by a combination of heat treatment and severe plastic deformation such as forging and rolling. The role of the fine-grained structure in determining the plastic formability was also investigated. The 0.2% proof stress and tensile strength of the heat-treated and multi-axial alternative forging (MAF) processed materials were both greater than 300 MPa. Subsequent cold rolling of these alloys increased both the 0.2% proof stress and tensile strength to over 450 MPa with a grain size of less than 1 μm. The fine-grained structure was confirmed to be effective in improving the strength of the 6N01 Al alloy.

Transplantation of coral fragment, Acropora formosa (Scleractinia)

2014 ◽  
pp. 1
Author(s):  
Hanny Tioho ◽  
Maykel A.J Karauwan
Keyword(s):  
Fragment Size ◽  
Observation Time ◽  
Minimum Size ◽  
Average Growth Rate ◽  
Average Growth ◽  
Significant Difference ◽  
Acropora Formosa ◽  
Survival And Growth ◽  
One Way Anova ◽  
Better Than

The minimum size of coral transplants, Acropora formosa, was assessed to support their survival and growth. For this, 150 coral fragments of different sizes (5, 10, 15 cm) were transplanted close to the donor colony. Their survivorship and growth were observed for 12 months. At the end of the observation time, 90% of 15 cm-transplanted coral fragments survived, while the others (10cm and 5 cm) did 86% and 82% respectively. The average growth rate of 5 cm-coral fragments was 0.860 cm/month, while 10 and 15 cm-fragments were 0.984 cm/month and 1.108 cm/month respectively. One-way ANOVA showed that there was significant difference (p<0.05) among the three (5, 10, 15 cm) transplant initial sizes in which the longest fragment size tended to survive longer than the smaller one.  However, the smaller transplants grew better than the bigger one, 10.318 cm/year (206%) for 5 cm-transplant, 11.803 cm/year (118%) for 10 cm-transplant, and 13.299 cm/year (89%) for 15 cm-transplant, respectively. Ukuran minimal fragmen karang Acropora formosa yang ditransplantasi diduga untuk mendukung ketahanan hidup dan pertumbuhannya. Untuk itu, 150 fragmen karang ditransplantasi ke lokasi yang berdekatan dengan koloni induknya.  Ketahanan hidup dan pertumbuhan semua fragmen karang yang ditransplantasi diamati selama 12 bulan.  Pada akhir pengamatan, 90% dari fragmen karang berukuran 15 cm yang ditransplantasi dapat bertahan hidup, sedangkan yang lainnya (ukuran 10 cm dan 5 cm) masing-masing sebesar 86% dan 82%.  Rata-rata laju pertumbuhan fragmen karang dengan ukuran awal 5 cm adalah 0,860 cm/bulan, sedangkan ukuran fragmen 10 dan 15 cm masing-masing adalah 0,984 cm/bulan and 1,108 cm/bulan. ANOVA satu arah menunjukkan adanya perbedaan yang nyata (p<0.05) antara ketiga ukuran fragmen yang berbeda, di mana ukuran fragmen karang yang lebih panjang cenderung mempunyai ketahanan hidup yang lebih baik. Namun demikian, ukuran transplant yang lebih kecil memiliki pertumbuhan lebih baik dibandingkan dengan ukuran yang lebih besar, yakni10,318 cm/tahun (206%) untuk transplant berukuran 5 cm, 11,803 cm/tahun (118%) untuk 10 cm, dan 13,299 cm/tahun (89%) untuk ukuran 15 cm.

Maximum Temperature Through a Yttrium Stabilized Zirconia Ceramic After Er,Cr:YSGG Laser Irradiation

2020 ◽  
Vol 02 ◽  
Author(s):  
Laurel Stringer ◽  
Sarah Malley ◽  
Darrell M. Hutto ◽  
Jason A. Griggs ◽  
Susana M. Salazar Marocho
Keyword(s):  
High Speed ◽  
Potential Method ◽  
Maximum Temperature ◽  
Zirconia Ceramic ◽  
Tooth Pulp ◽  
Control Group ◽  
Stabilized Zirconia ◽  
Significant Difference ◽  
Power Setting ◽  
Group A

Background: The most common approach to remove yttria stabilized zirconia (YSZ) fixed-dental prostheses (FDPs) is by means of diamond burs attached to a high-speed handpiece. This process is time-consuming and destructive. The use of lasers over mechanical instrumentation for removal of FDPs can lead to efficient and predictable restoration retrievability. However, the heat produced might damage the tooth pulp (>42˚C). Objective: The purpose of this study was to determine the maximum temperature (T) reached during the use of different settings of the erbium, chromium:yttrium-scandium-gallium-garnet Er,Cr:YSGG laser through a YSZ ceramic. Methods: YSZ slices (1 mm thick) were assigned into 7 groups. For the control group, a diamond bur was used to cut a 1 mm groove into the YSZ slices. For the 6 experimental groups, the laser was operated at a constant combination of 33% water and 66% air during 30 s with two different power settings (W) at three frequencies (PPS), as follows (W/PPS): 2.5/20, 2.5/30, 2.5/45, 4.5/20, 4.5/30, 4.5/45. The T through the YSZ slice was recorded in degrees Celsius by using a digital thermometer with a K thermocouple. Results: The median T of the control group was 26.5˚C. The use of 4.5 W resulted in the median T (˚C) of 44.2 at 20 PPS, 53.3 at 30 PPS, and 58.9 at 45 PPS, while 2.5 W showed 34.6, 31.6, and 25.0 at 20, 30, and 45 PPS, respectively. KruskalWallis one-way ANOVA showed that within each power setting, the T was similar. The high power and lowest frequency (4.5/20) showed no significant difference from the 2.5 W settings and the control group. Conclusion: The lower power setting (2.5 W) is a potential method for the use of the Er,Cr:YSGG laser to debond YSZ structures. The higher power (4.5 W) with high frequencies (30 and 45 PPS) is unsuitable.

scholarly journals Lignin-Containing Coatings for Packaging Materials—Pilot Trials

Polymers ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 1595
Author(s):  
Asif Javed ◽  
Peter Rättö ◽  
Lars Järnström ◽  
Henrik Ullsten
Keyword(s):  
High Speed ◽  
Water Solubility ◽  
Transmission Rate ◽  
Kraft Lignin ◽  
Packaging Materials ◽  
Water Contact ◽  
Pilot Trials ◽  
Significant Difference ◽  
Ph Level ◽  
Ammonium Zirconium Carbonate

One severe weakness of most biopolymers, in terms of their use as packaging materials, is their relatively high solubility in water. The addition of kraft lignin to starch coating formulations has been shown to reduce the water solubility of starch in dry coatings. However, lignin may also migrate into aqueous solutions. For this paper, kraft lignin isolated using the LignoBoost process was used in order to examine the effect of pH level on the solubility of lignin with and without ammonium zirconium carbonate (AZC). Machine-glazed (MG) paper was coated in a pilot coating machine, with the moving substrate at high speed, and laboratory-coated samples were used as a reference when measuring defects (number of pinholes). Kraft lignin became soluble in water at lower pH levels when starch was added to the solution, due to the interactions between starch and lignin. This made it possible to lower the pH of the coating solutions, resulting in increased water stability of the dry samples; that is, the migration of lignin to the model liquids decreased when the pH of the coating solutions was reduced. No significant difference was observed in the water vapor transmission rate (WVTR) between high and low pH for the pilot-coated samples. The addition of AZC to the formulation reduced the migration of lignin from the coatings to the model liquids and led to an increase in the water contact angle, but also increased the number of pinholes in the pilot-coated samples.

scholarly journals Submarine lava deltas of the 2018 eruption of Kīlauea volcano

2021 ◽  
Vol 83 (4) ◽  
Author(s):  
S. Adam Soule ◽  
Michael Zoeller ◽  
Carolyn Parcheta
Keyword(s):  
Grain Size ◽  
Pore Pressure ◽  
Mechanistic Model ◽  
Large Fraction ◽  
Volcanic Hazards ◽  
Lava Flows ◽  
Coarse Grained ◽  
Fine Grained ◽  
Fine Grain ◽  
Delta Formation

AbstractHawaiian and other ocean island lava flows that reach the coastline can deposit significant volumes of lava in submarine deltas. The catastrophic collapse of these deltas represents one of the most significant, but least predictable, volcanic hazards at ocean islands. The volume of lava deposited below sea level in delta-forming eruptions and the mechanisms of delta construction and destruction are rarely documented. Here, we report on bathymetric surveys and ROV observations following the Kīlauea 2018 eruption that, along with a comparison to the deltas formed at Pu‘u ‘Ō‘ō over the past decade, provide new insight into delta formation. Bathymetric differencing reveals that the 2018 deltas contain more than half of the total volume of lava erupted. In addition, we find that the 2018 deltas are comprised largely of coarse-grained volcanic breccias and intact lava flows, which contrast with those at Pu‘u ‘Ō‘ō that contain a large fraction of fine-grained hyaloclastite. We attribute this difference to less efficient fragmentation of the 2018 ‘a‘ā flows leading to fragmentation by collapse rather than hydrovolcanic explosion. We suggest a mechanistic model where the characteristic grain size influences the form and stability of the delta with fine grain size deltas (Pu‘u ‘Ō‘ō) experiencing larger landslides with greater run-out supported by increased pore pressure and with coarse grain size deltas (Kīlauea 2018) experiencing smaller landslides that quickly stop as the pore pressure rapidly dissipates. This difference, if validated for other lava deltas, would provide a means to assess potential delta stability in future eruptions.

Investigation on the mechanical properties of press-hardened boron steel sheets using the conductive heating technique

2020 ◽  
Vol 234 (8) ◽  
pp. 1084-1098
Author(s):  
O Kocar ◽  
H Livatyalı
Keyword(s):  
Mechanical Properties ◽  
High Speed ◽  
Boron Steel ◽  
Fast Heating ◽  
Heating Method ◽  
Conductive Heating ◽  
Press Hardening ◽  
High Speed Impact ◽  
Significant Difference ◽  
Structural Parts

An aluminized 22MnB5 (Boron) steel sheet, used for structural parts in the automotive industry, was subjected to press-hardening followed by austenitizing, both in a conventional furnace and via the conductive (electric resistance) heating method, an innovative technique based on the Joule’s principle for fast heating of the sheet metal. Conductive heating presents a number of advantages over the in-furnace heating method. These include a more efficient use of energy, as well as the requirement of less time and space for heating, thus lowering costs. After press-hardening was performed using both methods, the microstructural and mechanical characterizations of both specimens were examined for optical microscopy, hardness, tensile strength, and high-speed impact tests. The results showed that the press-hardening process transformed the ferritic–pearlitic microstructure in the as-received state into martensite after die quenching and caused a substantial increase in hardness and strength at the expense of ductility and impact toughness. On the other hand, no significant difference was observed in either the microstructure or mechanical properties with respect to the heating method used. The results obtained in the present investigation concur with the findings of current literature.

Betadine has a ciliotoxic effect on ciliated human respiratory cells

2014 ◽  
Vol 129 (S1) ◽  
pp. S45-S50 ◽  
Author(s):  
J H Kim ◽  
J Rimmer ◽  
N Mrad ◽  
S Ahmadzada ◽  
R J Harvey
Keyword(s):  
Epithelial Cells ◽  
High Speed ◽  
Imaging System ◽  
Beat Frequency ◽  
Ciliary Beat Frequency ◽  
Positive Control ◽  
Clinical Dose ◽  
Significant Difference ◽  
Sinonasal Mucosa ◽  
Ciliary Beat

AbstractObjective:This study investigated the effect of Betadine on ciliated human respiratory epithelial cells.Methods:Epithelial cells from human sinonasal mucosa were cultured at the air–liquid interface. The cultures were tested with Hanks' balanced salt solution containing 10 mM HEPES (control), 100 µM ATP (positive control), 5 per cent Betadine or 10 per cent Betadine (clinical dose). Ciliary beat frequency was analysed using a high-speed camera on a computer imaging system.Results:Undiluted 10 per cent Betadine (n = 6) decreased the proportion of actively beating cilia over 1 minute (p < 0.01). Ciliary beat frequency decreased from 11.15 ± 4.64 Hz to no detectable activity. The result was similar with 5 per cent Betadine (n = 7), with no significant difference compared with the 10 per cent solution findings.Conclusion:Betadine, at either 5 and 10 per cent, was ciliotoxic. Caution should be applied to the use of topical Betadine solution on the respiratory mucosal surface.

scholarly journals High-speed panoramic light-sheet microscopy reveals global endodermal cell dynamics

2013 ◽  
Vol 4 (1) ◽  
Author(s):  
Benjamin Schmid ◽  
Gopi Shah ◽  
Nico Scherf ◽  
Michael Weber ◽  
Konstantin Thierbach ◽  
...  
Keyword(s):  
High Speed ◽  
Light Sheet ◽  
Endodermal Cell ◽  
Cell Dynamics ◽  
Light Sheet Microscopy

scholarly journals THE IDEAL DISTRIBUTION OF FARMERS: EXPLAINING THE EURO-AMERICAN SETTLEMENT OF UTAH

2017 ◽  
Vol 83 (1) ◽  
pp. 75-90 ◽  
Author(s):  
Peter M. Yaworsky ◽  
Brian F. Codding
Keyword(s):  
Population Density ◽  
Ideal Free Distribution ◽  
Negative Relationship ◽  
Coarse Grained ◽  
Distribution Model ◽  
Test Model ◽  
Fine Grained ◽  
Fine Grain ◽  
Model Predictions ◽  
The Ideal

Explaining how and why populations settle a new landscape is central to many questions in American archaeology. Recent advances in settlement research have adopted predictions from the Ideal Free Distribution model (IFD). While tests of IFD predictions to date rely either on archaeologically derived coarse-grained diachronic data or ethnographically derived fine-grained synchronic data, here we provide the first test using historically derived data that is both fine-grained and diachronic. Fine-grain diachronic data allow us to test model predictions at a temporal scale in line with human settlement decisions and to validate proxies for application in archaeological contexts. To test model predictions pertaining to the relationship between population density and habitat quality, we use data from the historical settlement of Utah. The results demonstrate a negative relationship between population density and the quality of habitats occupied. These results are consistent with IFD predictions, suggesting that Euro-American settlement of Utah resulted from individuals attempting to maximize individual returns via agricultural productivity. Our results provide a quantitative and testable explanation for population dispersion over time and explain the spatial distribution of population density today. The results support predictions derived from a general theory of behavior, providing an explanatory framework for colonization events worldwide.

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