The Experts below are selected from a list of 1236 Experts worldwide ranked by ideXlab platform
Matthias Wessling - One of the best experts on this subject based on the ideXlab platform.
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rotating microstructured Spinnerets produce helical ridge membranes to overcome mass transfer limitations
Journal of Membrane Science, 2022Co-Authors: Tobias Luelf, Maik Tepper, Lukas Fehlemann, Jens Rubner, Hannah Roth, Matthias WesslingAbstract:Abstract Membrane geometry evolution boosts membrane applications to become even more sustainable, resource- and energy-efficient. This evolution is crucial as increasingly permeable membrane materials introduce the major drawback of promoting fluid resistance due to boundary layer formation. We present how to break these boundary layers with Helical Ridge Membranes produced by rotating microstructured Spinnerets. 3D printing enables us to manufacture polymeric, microstructured Spinnerets featuring grooved orifices. When integrating these Spinnerets into a wet spinning process, microstructured hollow fiber membrane surfaces evolve. Our home-engineered spinning technology sets the spinneret in motion. Rotation twists the nascent microstructure and creates a helical ridge on the lumen side. A robust spinning process especially establishes for our novel spinneret device to rotate the needle inside the spinneret. The interplay of spinning conditions and spinneret rotation uncovers a range of producible helical ridge shapes, sizes and pitches. In addition, spinneret rotation speed affects intrinsic membrane properties, about which we derive general correlations. The helical ridges prove the manipulation of hydrodynamics inside hollow fiber membranes by inducing secondary flow. The latter enhances mass transfer to diminish boundary layers. Ultimately, a cross-flow ultrafiltration showcase reveals TMP gradients reduced by 350 % and demonstrates the disruptive impact of Helical Ridge Membranes on membrane filtration.
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3D-printed rotating Spinnerets create membranes with a twist
Journal of Membrane Science, 2018Co-Authors: Tobias Luelf, Deniz Rall, Denis Wypysek, Martin Wiese, Tim Femmer, Christian Bremer, Jan Ulrich Michaelis, Matthias WesslingAbstract:Abstract Round hollow fiber membranes have been well established in applications such as gas separation, ultrafiltration and blood dialysis. Yet, it is well known that geometrical topologies can introduce secondary flow patterns counteracting mass transport limitations, stemming from diffusion resistances and fouling. We present a new systematic methodology to fabricate novel membrane architectures. We use the freedom of design by 3D-printing Spinnerets, having multiple bore channels of any geometry. First, such Spinnerets are stationary to fabricate straight bore channels inside a monolithic membrane. Second, in an even more complex design, a new mechanical system enables rotating the spinneret. Such rotating multibore Spinnerets enable (A) the preparation of twisted channels inside a porous monolithic membrane as well as (B) a helical twist of the outside geometry. The spun material systems comprise classical polymer solutions as well as metal-polymer slurries resulting in solid porous metallic monolithic membrane after thermal post-processing. It is known that twisted spiral-type bore channel geometries are potentially superior to straight channels with respect to mass and heat polarization phenomena, however their fabrication was cumbersome in the past. Now, the described methodology enables membrane fabrication to tailor the membrane geometry to the needs of the membrane process. To showcase the delicate interplay between the geometry and radial and axial flow conditions, we report fluid mechanical simulations and flow magnetic resonance imaging measurements for a twisted tri-bore membrane during permeation.
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3d nanofabrication inside rapid prototyped microfluidic channels showcased by wet spinning of single micrometre fibres
Lab on a Chip, 2018Co-Authors: Matthias Wessling, Jonas Lolsberg, John Linkhorst, Arne Cinar, Alexander Jans, Alexander J C KuehneAbstract:Microfluidics is an established multidisciplinary research domain with widespread applications in the fields of medicine, biotechnology and engineering. Conventional production methods of microfluidic chips have been limited to planar structures, preventing the exploitation of truly three-dimensional architectures for applications such as multi-phase droplet preparation or wet-phase fibre spinning. Here the challenge of nanofabrication inside a microfluidic chip is tackled for the showcase of a spider-inspired spinneret. Multiphoton lithography, an additive manufacturing method, was used to produce free-form microfluidic masters, subsequently replicated by soft lithography. Into the resulting microfluidic device, a three-dimensional spider-inspired spinneret was directly fabricated in-chip via multiphoton lithography. Applying this unprecedented fabrication strategy, the to date smallest printed spinneret nozzle is produced. This spinneret resides tightly sealed, connecting it to the macroscopic world. Its functionality is demonstrated by wet-spinning of single-digit micron fibres through a polyacrylonitrile coagulation process induced by a water sheath layer. The methodology developed here demonstrates fabrication strategies to interface complex architectures into classical microfluidic platforms. Using multiphoton lithography for in-chip fabrication adopts a high spatial resolution technology for improving geometry and thus flow control inside microfluidic chips. The showcased fabrication methodology is generic and will be applicable to multiple challenges in fluid control and beyond.
Gerhard Gries - One of the best experts on this subject based on the ideXlab platform.
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multimodal and multifunctional signaling web reduction courtship behavior in a north american population of the false black widow spider
PLOS ONE, 2020Co-Authors: Andreas Fischer, Jamielynne S Varney, Adam J Blake, Stephen Takacs, Gerhard GriesAbstract:Males of widow spiders courting on the web of females engage in web-reduction behavior which entails excising a section of the web, bundling it up, and wrapping it with their silk. Males of the false black widow spider, Steatoda grossa, in European populations also produce stridulatory courtship sound which has not yet been studied in their invaded North American range. Working with a North American population of S. grossa, we tested the hypotheses that (1) web reduction by males renders webs less attractive to rival males; (2) deposition of silk by courting males has an inter-sexual (male-female) signal function that enhances their likelihood of copulation; and (3) stridulatory sound is a courtship signal of males. Testing anemotactic attraction of males in Y-tube olfactometer experiments revealed that reduced webs (indicative of a mated female) and intact webs (indicative of a virgin female) were equally attractive to males. Recording courtship behavior of males with either functional (silk-releasing) Spinnerets or Spinnerets experimentally occluded on the web of virgin females showed that males with functional Spinnerets were more likely to copulate with the female they courted. Although males possess the stridulatory apparatus to produce courtship sound, they did not stridulate when courting or copulating on the web of females. Our data support the conclusion that web-reduction behavior of S. grossa males in their invaded North American range has no long-range effect on mate seeking males. Instead, web-reduction behavior has an inter-sexual signaling function that seems to be linked to functional Spinnerets of the courting male. The signal produced by a male likely entails a volatile silk-borne pheromone, but may also embody a gauge of his endurance (the amount of time he engages in web reduction causing web vibrations).
Myungjin Moon - One of the best experts on this subject based on the ideXlab platform.
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Organization of the Spinnerets and spigots in the orb web spider, Argiope bruennichi (Araneae: Araneidae)
Entomological Research, 2012Co-Authors: Myungjin MoonAbstract:Although the basic taxonomic characteristics usually remain unchanged, some spinning apparatuses undergo consistent adaptive variations. As the presence of additional protuberances known as nubbins and tartipores have caused disagreements regarding some Araneidae spiders, more detailed definitions on the cuticular structures have recently been proposed. Reflecting this definition, microstructural organization of silk spinning apparatuses in the orb web spider Argiope bruennichi were reconsidered using field emission scanning electron microscopy. Among the seven kinds of functional spigots in females, it was revealed that two types (major ampullates and pyrifoms) are located on anterior Spinnerets and another five types are distributed on median (minor ampullates, tubuliforms and aciniforms) or posterior (tubuliforms, flagelliforms, aggregates and aciniforms) Spinnerets, respectively. In addition to functional spigots, cuticular remnants of the nubbins and the tartipores were found on the spinning fields, but the number of tartipores on each spinneret varied among individuals based on maturity. Nevertheless, three kinds of cuticular protuberances of ampullate silk glands were clearly visible at both the anterior and median Spinnerets.
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fine structure of the silk spigots in the spider dolomedes sulfureus araneae pisauridae
Applied Microscopy, 2008Co-Authors: Myungjin MoonAbstract:Dolomedes spiders of the family Pisauridae are one of free wandering spiders with semi-aquatic habitation. They do not build web for prey-hunting but build a nursery web for spiderlings. This paper describes the fine structure of the silkspinning spigots of the fishing spider Dolomedes sulfureus revealed by the field emission scanning electron microscope (FESEM). The fishing spider Dolomedes sulfureus possesses only three types of silk glands which connected through the typical spinning tubes on the Spinnerets. The silk spigots of this spider were identified as three groups: ampullates, pyriforms and aciniforms. Two pairs of major ampullate glands send secretory ductules to the anterior Spinnerets, and another two pairs (or 1~2 pairs in males) of minor ampullate glands supply the middle Spinnerets. In addition, the pyriform glands feed silk into the anterior Spinnerets (62~68 pairs in females and 45~50 pairs in males), and the aciniforms send ductules to the middle (33~40 pairs in females and 18~25 pairs in males) and the posterior Spinnerets (42~50 pairs in females and 24~28 pairs in males). Among these, the ampullate one is the most predominate gland in both sexes.
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microstructure of the silk apparatus of the comb footed spider achaearanea tepidariorum araneae theridiidae
Entomological Research, 2006Co-Authors: Myungjin Moon, A N JeongsuAbstract:The microstructural organization of the silk-spinning apparatus of the comb-footed spider, Achaearanea tepidariorum, was observed by using a field emission scanning electron microscope. The silk glands of the spider were classified into six groups: ampullate, tubuliform, flagelliform, aggregate, aciniform and pyriform glands. Among these, three types of silk glands, the ampullate, pyriform and aciniform glands, occur only in female spiders. One (adult) or two (subadult) pairs of major ampullate glands send secretory ductules to the anterior Spinnerets, and another pair of minor ampullate glands supply the median Spinnerets. Three pairs of tubuliform glands in female spiders send secretory ductules to the median (one pair) and posterior (two pairs) Spinnerets. Furthermore, one pair of flagelliform glands and two pairs of aggregate glands together supply the posterior Spinnerets, and form a characteristic spinning structure known as a “triad” spigot. In male spiders, this combined apparatus of the flagelliform and the aggregate spigots for capture thread production is not apparent, instead only a non-functional remnant of this triad spigot is present. In addition, the aciniform glands send ductules to the median (two pairs) and the posterior Spinnerets (12–16 pairs), and the pyriform glands feed silk into the anterior Spinnerets (90–100 pairs in females and 45–50 pairs in males).
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microstructure of the silk spinning nozzles in the lynx spider oxyopes licenti araneae oxyopidae
Animal Cells and Systems, 2006Co-Authors: Myungjin MoonAbstract:Abstract The lynx spiders are free wandering spiders with long spines on their legs. They do not build web, but hunt small insects on plants. In spite of the facts that the wandering spiders do not produce webs for prey‐catching, they also have silk apparatuses even though the functions are not fully defined. This paper describes the microstructural organization of the silk‐spinning nozzles and its silk glands of the lynx spider, Oxyopes licenti, revealed by the field emission scanning electron microscope (FESEM). The silk‐spinning nozzles of this spider were identified as three groups: ampullate, pyriform and aciniform glands. Each group of silk gland feed silk into one of the three pairs of Spinnerets. Two pairs of major ampullate glands send secretory ductules to the anterior Spinnerets, and another two pair of minor ampullate glands supply the middle Spinnerets. In addition, the pyriform glands feed silk into the anterior Spinnerets (25–30 pairs in females and 24–40 pairs in males), and the aciniform ...
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Spinneret Microstructure of the Silk Spinning Apparatus in the Crab Spider, Misumenops tricuspidatus (Araneae: Thomisidae)
Entomological Research, 2005Co-Authors: Myungjin Moon, Jeong-su AnAbstract:The silk spinning apparatus in the crab spider, Misumenops tricuspidatus was studied with the field emission scanning electron microscope (FESEM) and the main microstructural characteristics of the silk glands are presented. In spite of the fact that the crab spiders do not spin webs to trap a prey, they also have silk apparatus even though the functions are not fully defined. The crab spider, Misumenops tricuspidatus possesses only three types of silk glands which connected through the typical spinning tubes on the Spinnerets. The spinning apparatus of Misumenops closely corresponds to that of wandering spiders such as jumping spiders or wolf spiders except some local variations. Anterior Spinnerets comprise 2 pairs of the ampullates and 48 (±5) pairs of pyriform glands. Another 2 pairs of ampullate glands and nearly 20 (±3) pairs of aciniform glands were connected on the middle Spinnerets. Additional 50 (±5) pairs of the aciniform glands were connected on the posterior Spinnerets. The aggregate glands and the flagelliform glands which have the function of sticky capture thread production in orb-web spiders as well as the tubuliform glands for cocoon production in females were not developed at both sexes of this spider, characteristically.
Tobias Luelf - One of the best experts on this subject based on the ideXlab platform.
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rotating microstructured Spinnerets produce helical ridge membranes to overcome mass transfer limitations
Journal of Membrane Science, 2022Co-Authors: Tobias Luelf, Maik Tepper, Lukas Fehlemann, Jens Rubner, Hannah Roth, Matthias WesslingAbstract:Abstract Membrane geometry evolution boosts membrane applications to become even more sustainable, resource- and energy-efficient. This evolution is crucial as increasingly permeable membrane materials introduce the major drawback of promoting fluid resistance due to boundary layer formation. We present how to break these boundary layers with Helical Ridge Membranes produced by rotating microstructured Spinnerets. 3D printing enables us to manufacture polymeric, microstructured Spinnerets featuring grooved orifices. When integrating these Spinnerets into a wet spinning process, microstructured hollow fiber membrane surfaces evolve. Our home-engineered spinning technology sets the spinneret in motion. Rotation twists the nascent microstructure and creates a helical ridge on the lumen side. A robust spinning process especially establishes for our novel spinneret device to rotate the needle inside the spinneret. The interplay of spinning conditions and spinneret rotation uncovers a range of producible helical ridge shapes, sizes and pitches. In addition, spinneret rotation speed affects intrinsic membrane properties, about which we derive general correlations. The helical ridges prove the manipulation of hydrodynamics inside hollow fiber membranes by inducing secondary flow. The latter enhances mass transfer to diminish boundary layers. Ultimately, a cross-flow ultrafiltration showcase reveals TMP gradients reduced by 350 % and demonstrates the disruptive impact of Helical Ridge Membranes on membrane filtration.
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3D-printed rotating Spinnerets create membranes with a twist
Journal of Membrane Science, 2018Co-Authors: Tobias Luelf, Deniz Rall, Denis Wypysek, Martin Wiese, Tim Femmer, Christian Bremer, Jan Ulrich Michaelis, Matthias WesslingAbstract:Abstract Round hollow fiber membranes have been well established in applications such as gas separation, ultrafiltration and blood dialysis. Yet, it is well known that geometrical topologies can introduce secondary flow patterns counteracting mass transport limitations, stemming from diffusion resistances and fouling. We present a new systematic methodology to fabricate novel membrane architectures. We use the freedom of design by 3D-printing Spinnerets, having multiple bore channels of any geometry. First, such Spinnerets are stationary to fabricate straight bore channels inside a monolithic membrane. Second, in an even more complex design, a new mechanical system enables rotating the spinneret. Such rotating multibore Spinnerets enable (A) the preparation of twisted channels inside a porous monolithic membrane as well as (B) a helical twist of the outside geometry. The spun material systems comprise classical polymer solutions as well as metal-polymer slurries resulting in solid porous metallic monolithic membrane after thermal post-processing. It is known that twisted spiral-type bore channel geometries are potentially superior to straight channels with respect to mass and heat polarization phenomena, however their fabrication was cumbersome in the past. Now, the described methodology enables membrane fabrication to tailor the membrane geometry to the needs of the membrane process. To showcase the delicate interplay between the geometry and radial and axial flow conditions, we report fluid mechanical simulations and flow magnetic resonance imaging measurements for a twisted tri-bore membrane during permeation.
Andreas Fischer - One of the best experts on this subject based on the ideXlab platform.
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multimodal and multifunctional signaling web reduction courtship behavior in a north american population of the false black widow spider
PLOS ONE, 2020Co-Authors: Andreas Fischer, Jamielynne S Varney, Adam J Blake, Stephen Takacs, Gerhard GriesAbstract:Males of widow spiders courting on the web of females engage in web-reduction behavior which entails excising a section of the web, bundling it up, and wrapping it with their silk. Males of the false black widow spider, Steatoda grossa, in European populations also produce stridulatory courtship sound which has not yet been studied in their invaded North American range. Working with a North American population of S. grossa, we tested the hypotheses that (1) web reduction by males renders webs less attractive to rival males; (2) deposition of silk by courting males has an inter-sexual (male-female) signal function that enhances their likelihood of copulation; and (3) stridulatory sound is a courtship signal of males. Testing anemotactic attraction of males in Y-tube olfactometer experiments revealed that reduced webs (indicative of a mated female) and intact webs (indicative of a virgin female) were equally attractive to males. Recording courtship behavior of males with either functional (silk-releasing) Spinnerets or Spinnerets experimentally occluded on the web of virgin females showed that males with functional Spinnerets were more likely to copulate with the female they courted. Although males possess the stridulatory apparatus to produce courtship sound, they did not stridulate when courting or copulating on the web of females. Our data support the conclusion that web-reduction behavior of S. grossa males in their invaded North American range has no long-range effect on mate seeking males. Instead, web-reduction behavior has an inter-sexual signaling function that seems to be linked to functional Spinnerets of the courting male. The signal produced by a male likely entails a volatile silk-borne pheromone, but may also embody a gauge of his endurance (the amount of time he engages in web reduction causing web vibrations).