High-speed filtration using highly porous fiber media for advanced and compact particle removal

2014 ◽  
Vol 14 (5) ◽  
pp. 735-742 ◽  
Author(s):  
Heidi B. Guerra ◽  
Siping Niu ◽  
Kisoo Park ◽  
Youngchul Kim
Keyword(s):  
High Speed ◽  
Filtration Rate ◽  
Polypropylene Fiber ◽  
High Rate ◽  
High Porosity ◽  
Particle Removal ◽  
Polyaluminum Chloride ◽  
Operating Variables ◽  
The Impact ◽  
Highly Porous

Since its recent introduction to the filtration industry, one of the major concerns about the use of fiber in water treatment has been its applicability for high-rate filtration while minimizing the build-up of headloss. In this study, a compact, modular filter employing non-woven, highly porous polypropylene fiber as filter media was investigated for the treatment of turbid water under high filtration rates. The impact of different operating variables such as polyaluminum chloride (PAC) dose and filtration rate on the effluent turbidity and headloss were investigated. Due to the fiber's high porosity, the filter was able to retain solids at a filtration rate of up to 1,500 m/day without headloss. When PAC was added, the effluent turbidity decreased significantly with the lowest observed when the dose was 1 mg/L. Furthermore, the effluent turbidity was found to increase with the filtration rate. During all the experiments, no headloss was observed except when the filtration rate was 2,250 m/day or when the PAC dose was 5 mg/L. In terms of its compactness and applicability at very high filtration rates, the polypropylene fiber filter can have a considerable advantage compared to other filters.

scholarly journals Effect of different helmet shell configurations on the protection against head trauma

2019 ◽  
Vol 54 (7-8) ◽  
pp. 408-415 ◽  
Author(s):  
Marta Palomar ◽  
Ricardo Belda ◽  
Eugenio Giner
Keyword(s):  
Head Trauma ◽  
High Speed ◽  
Composite Shell ◽  
Human Head ◽  
High Rate ◽  
Finite Element Models ◽  
High Speed Impact ◽  
Full Metal Jacket ◽  
The Impact ◽  
Single Combat

Head trauma following a ballistic impact in a helmeted head is assessed in this work by means of finite element models. Both the helmet and the head models employed were validated against experimental high-rate impact tests in a previous work. Four different composite ply configurations were tested on the helmet shell, and the energy absorption and the injury outcome resulting from a high-speed impact with full metal jacket bullets were computed. Results reveal that hybrid aramid–polyethylene configurations do not prevent bullet penetration at high velocities, while 16-layer aramid configurations are superior in dissipating the energy absorbed from the impact. The fabric orientation of these laminates proved to be determinant for the injury outcome, as maintaining the same orientations for all the layers led to basilar skull fractures (dangerous), while alternating orientation of the adjacent plies resulted in an undamaged skull. To the authors knowledge, no previous work in the literature has analysed numerically the influence of different stack configurations on a single combat helmet composite shell on human head trauma.

A pilot-scale study of Cryptosporidium-sized microsphere removals from swimming pools via sand filtration

2015 ◽  
Vol 14 (1) ◽  
pp. 109-120 ◽  
Author(s):  
Ping Lu ◽  
James E. Amburgey
Keyword(s):  
Filtration Rate ◽  
Pilot Scale ◽  
Cryptosporidium Species ◽  
High Rate ◽  
Organic Polymer ◽  
Recreational Water ◽  
Sand Filtration ◽  
Polyaluminum Chloride ◽  
Overall Performance ◽  
Over Time

Cryptosporidium species are the most common cause of gastrointestinal illness in treated recreational water venues. In order to protect public health during swimming, Cryptosporidium-sized microsphere removals by high-rate sand filtration with six coagulants were evaluated with a 5.5 m3 pilot-scale swimming pool. A sand filter without coagulation removed 20–63% of Cryptosporidium-sized microspheres. Cryptosporidium-sized microsphere removals exceeded 98% by sand filtration with five of the six tested coagulants. Continuously feeding coagulants A, B, and F (i.e., organic polymers) led to coagulant accumulation in the system and decreased removals over time (<2 days). Coagulant E (polyaluminum chloride) consistently removed more than 90% of microspheres at 30 m/h while the removals dropped to approximately 50% at a filtration rate of 37 m/h. Coagulant C was a chitosan-based product that removed fewer microspheres compared with other products, <75%, under the studied conditions. Results indicated aluminum-based coagulants (coagulants D and E) had an overall performance advantage over the organic polymer based coagulants primarily in terms of their tendency not to accumulate in the water and cease to be effective at improving filter efficiency.

scholarly journals Propagation of a Plastic Wave in Snow

1977 ◽  
Vol 19 (81) ◽  
pp. 175-183 ◽  
Author(s):  
Gorow Wakahama ◽  
Atsushi Sato
Keyword(s):  
Water Content ◽  
Wave Velocity ◽  
High Speed ◽  
Free Water ◽  
The Body ◽  
High Rate ◽  
Plastic Wave ◽  
Free Water Content ◽  
Moving Body ◽  
The Impact

AbstractWhen snow is pushed very fast by a moving body a plastic wave is generated at the head of the body. If the velocity of the moving body becomes close to that of the plastic wave, the snow may exert a great resistive force against the body as predicted by Yosida. It is, therefore, very important to study the dynamic behaviour of snow at a high rate of deformation, such as takes place when a snow plough is used on the highway, a train runs on a railroad covered with snow, or an avalanche occurs. Hence, this study is concerned with the safety and maintenance of winter traffic and transportation, and also with the generation and propagation of an avalanche. In order to clarify the detailed processes of the deformation of snow at high rates, laboratory experiments were made by compressing snow at high speed. The propagation of a plastic wave through snow was observed by using a high-speed camera and a pressure-detecting device. Analyses of the data obtained gave the velocity of the plastic wave for various kinds of snow whose density ranged from 0.17 to 0.46 Mg m-3and free-water content from o to 17%, whereby studies were made into the dependences on the density and free-water content of the velocity of the plastic wave. When the impact velocity was 4.3 ± 0.2 m s-1, the wave velocity ranged from 5 m s-1for a new snow to 12 m s-1for a fine-grained, well-settled snow. The plastic-wave velocity in wet snow was, in general, smaller than that in dry snow of the same density. Changes in density and structure of snow associated with the passage of a plastic wave were studied and discussed. The pressure at the wave front was measured; values of 0.1-0.3 bar were obtained, these are of the same order as the value estimated from theoretical formulae. The plastic-wave velocity was also observed for a confined snow, which showed a larger velocity and plastic strain than an unconfined snow.

scholarly journals Propagation of a Plastic Wave in Snow

1977 ◽  
Vol 19 (81) ◽  
pp. 175-183 ◽  
Author(s):  
Gorow Wakahama ◽  
Atsushi Sato
Keyword(s):  
Water Content ◽  
Wave Velocity ◽  
High Speed ◽  
Free Water ◽  
The Body ◽  
High Rate ◽  
Plastic Wave ◽  
Free Water Content ◽  
Moving Body ◽  
The Impact

AbstractWhen snow is pushed very fast by a moving body a plastic wave is generated at the head of the body. If the velocity of the moving body becomes close to that of the plastic wave, the snow may exert a great resistive force against the body as predicted by Yosida. It is, therefore, very important to study the dynamic behaviour of snow at a high rate of deformation, such as takes place when a snow plough is used on the highway, a train runs on a railroad covered with snow, or an avalanche occurs. Hence, this study is concerned with the safety and maintenance of winter traffic and transportation, and also with the generation and propagation of an avalanche. In order to clarify the detailed processes of the deformation of snow at high rates, laboratory experiments were made by compressing snow at high speed. The propagation of a plastic wave through snow was observed by using a high-speed camera and a pressure-detecting device. Analyses of the data obtained gave the velocity of the plastic wave for various kinds of snow whose density ranged from 0.17 to 0.46 Mg m-3 and free-water content from o to 17%, whereby studies were made into the dependences on the density and free-water content of the velocity of the plastic wave. When the impact velocity was 4.3 ± 0.2 m s-1, the wave velocity ranged from 5 m s-1 for a new snow to 12 m s-1 for a fine-grained, well-settled snow. The plastic-wave velocity in wet snow was, in general, smaller than that in dry snow of the same density. Changes in density and structure of snow associated with the passage of a plastic wave were studied and discussed. The pressure at the wave front was measured; values of 0.1-0.3 bar were obtained, these are of the same order as the value estimated from theoretical formulae. The plastic-wave velocity was also observed for a confined snow, which showed a larger velocity and plastic strain than an unconfined snow.

Uniformity of Nanofiber Alignment by Electrospinning

2011 ◽  
Vol 287-290 ◽  
pp. 2635-2639 ◽  
Author(s):  
Yi Jun Pan ◽  
Chien Kuo Yen ◽  
Feng Wei Cheng ◽  
Wen Hao Hsing ◽  
Wei Sheng Chuang
Keyword(s):  
Electric Field ◽  
High Speed ◽  
Angle Distribution ◽  
Analysis Software ◽  
Fiber Alignment ◽  
Operating Variables ◽  
Fiber Deposition ◽  
Nanofiber Alignment ◽  
The Impact ◽  
Effective Analysis

Electrospinning of polyacrylonitrile was used to investigate the effect of horizontal vs. vertical fiber deposition methods and operating variables on the degree of nanofiber alignment. A high-speed camera and Fiji image analysis software were used to assess differences and changes in the degree of fiber parallelism, allowing for effective analysis of the impact of operating variables on fiber parallel alignment. The results show that the strength of the electric field affects the fibers to assume a parallel alignment. Too weak the electric field, the fibers are unable to form a straight bundle, but too strong a field results in chaotic fiber alignment. The distance between the collectors influences the angle distribution of the fiber parallel alignment greatly. Comparing the effect of horizontal and vertical electrospinning on fiber alignment shows that horizontal results in a more optimal degree of parallel fiber alignment.

scholarly journals Highly Porous Free-Standing rGO/SnO2 Pseudocapacitive Cathodes for High-Rate and Long-Cycling Al-Ion Batteries

Nanomaterials ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 2024
Author(s):  
Timotheus Jahnke ◽  
Leila Raafat ◽  
Daniel Hotz ◽  
Andrea Knöller ◽  
Achim Max Diem ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Energy Storage ◽  
Reduced Graphene Oxide ◽  
Electrode Materials ◽  
Lithium Ion ◽  
High Rate ◽  
High Porosity ◽  
Reduced Graphene ◽  
Ion Species ◽  
Highly Porous

Establishing energy storage systems beyond conventional lithium ion batteries requires the development of novel types of electrode materials. Such materials should be capable of accommodating ion species other than Li+, and ideally, these ion species should be of multivalent nature, such as Al3+. Along this line, we introduce a highly porous aerogel cathode composed of reduced graphene oxide, which is loaded with nanostructured SnO2. This binder-free hybrid not only exhibits an outstanding mechanical performance, but also unites the pseudocapacity of the reduced graphene oxide and the electrochemical storage capacity of the SnO2 nanoplatelets. Moreover, the combination of both materials gives rise to additional intercalation sites at their interface, further contributing to the total capacity of up to 16 mAh cm−3 at a charging rate of 2 C. The high porosity (99.9%) of the hybrid and the synergy of its components yield a cathode material for high-rate (up to 20 C) aluminum ion batteries, which exhibit an excellent cycling stability over 10,000 tested cycles. The electrode design proposed here has a great potential to meet future energy and power density demands for advanced energy storage devices.

Experimental study on non-woven filamentous fibre micro-filter with high filtration speed

2015 ◽  
Vol 71 (9) ◽  
pp. 1414-1422 ◽  
Author(s):  
Siping Niu ◽  
Kisoo Park ◽  
Heidi B. Guerra ◽  
Youngchul Kim
Keyword(s):  
Filtration Rate ◽  
Experimental Studies ◽  
Head Loss ◽  
High Rate ◽  
High Porosity ◽  
Raw Water ◽  
Water Turbidity ◽  
Filter Performance ◽  
Filter Process ◽  
Filter Aid

A laboratory study was undertaken to pursue the filter performance of a micro-filter module employing highly porous fibre media under a high filtration rate (≥1,500 m/day), faster than that of any conventional filter process. The effects of filtration rate, head loss, raw water turbidity, and filter aid chemicals on filter performance were analysed. In spite of the extremely high filtration rate, the filter achieved an attractive efficiency, reducing the raw water turbidity by over 80%. As with other filter systems, the filter aid used ((polyaluminium chloride (PAC)) greatly affected the performance of this particular fibre filter. Long-term repetitive runs were additionally carried out to confirm the reproducibility of the filter performance. Also, a comparison was carried out with other high-rate filter systems which are either being tested for use in experimental studies, or are already commercially available. This study reveals that the filter performance under a high filtration speed is still attractive especially as PAC is used. Due to the high porosity of the fibre, the filter had small head loss even though the filtration rate was high. These results ascertain that it is possible to operate the filters with high filtration rate achieving reliable treatment performance.

Water Impact-Abrasion Erosion of Hybrid Fiber-Reinforced High Performance Concrete

2020 ◽  
Vol 30 ◽  
pp. 63-72
Author(s):  
Sajjad H. Ali ◽  
Nadheer S. Ayoob ◽  
Munther L. Abdul Hussein ◽  
Sallal R. Abid
Keyword(s):  
Abrasion Resistance ◽  
High Speed ◽  
High Performance ◽  
Steel Fiber ◽  
High Performance Concrete ◽  
Polypropylene Fiber ◽  
Hybrid Fiber ◽  
Normal Concrete ◽  
The One ◽  
The Impact

Aiming to evaluate the resistance of High Performance Concrete (HPC) against the abrasion erosion due to the continual impact of water and water borne materials, six HPC mixtures reinforced with different fibers and fiber combinations were prepared and tested experimentally in this study. All mixtures share the same contents of all materials, while the types and combinations of fibers used were different among the mixtures. All mixtures included a total of 2.5% volumetric content of fibers. The mixture S6 included pure 6 mm micro-steel fiber (S6), S15 mixture included pure 15 mm micro-steel fiber (S15), while the S6-S15 mixture included 1.25% of each of S6 and S15. S6-PP and S15-PP included 2.0% of S6 or S15, respectively, in combination with 0.5% of polypropylene fiber (PP), while the sixth mixture included 1.0% S6, 1.0% S15 and 0.5% PP. The impact abrasion test was conducted on 200×200 mm plat targets with 50 mm thickness that were fixed perpendicular to a water jet with a high speed of 20 m/s. The results revealed that all HPC mixtures exhibited much higher abrasion resistance than normal concrete. The results also showed that the S15 mixture was the one with highest abrasion resistance with an abrasion loss of only approximately 20 grams after 12 hours testing.

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