Design, Performance and Reinforcement of Bearing-Free Soft Silicone Combustion-Driven Pumps

We present a design and parameter study on 3D-printed, lost-wax-casted and combustion-powered soft silicone pumps, which are internally cooled by the conveyed liquid. Important factors influencing the pumping performance such as gas mixtures, feed rates, and actuation frequencies were thoroughly studied. Furthermore, we reinforced some of the here presented pumps with aramid fabrics in order to achieve partial blocking of the elastomeric flexibility upon combustion expansion. This design measure dramatically increased the pumping capabilities and allowed continuous conveying of water to 13 m (corresponding to 42 ft) of height. We were able to stably operate these novel pumps for more than 30 000 combustion cycles. Therefore, they represent a further step toward long-term stable soft machines with dense power characteristics

Rapid Production of a Porous Cellulose Acetate Membrane for Water Filtration using Readily Available Chemicals

A chemistry laboratory experiment using everyday items and readily available chemicals is described to introduce advanced high school students and undergraduate college students to porous polymer membranes. In a three-step manufacturing process, a membrane is produced at room temperature. The filtration principle of the membrane is then illustrated by filtering solutions containing pigmentary watercolor or food coloring. A comparison of the filtration results shows that insoluble watercolor pigments are too large to pass the pores of the membrane and are successfully rejected by the membrane, whereas the food coloring is completely soluble in water and easily passes the membrane. The laboratory experiment can be performed in a 2 h activity and serves the purpose of (1) exposing students to a new and interesting field of material science. It (2) makes them familiar with porous membranes for the production of safe drinking water and (3) introduces them to a template-removal technique utilizing acid/base theory. There were 52 advanced high school students and 55 high school teachers in Switzerland who already successfully performed the laboratory experiment and found the activity engaging and motivating

Rapid Production of a Porous Cellulose Acetate Membrane for Water Filtration using Readily Available Chemicals

A chemistry laboratory experiment using everyday items and readily available chemicals is described to introduce advanced high school students and undergraduate college students to porous polymer membranes. In a three-step manufacturing process, a membrane is produced at room temperature. The filtration principle of the membrane is then illustrated by filtering solutions containing pigmentary watercolor or food coloring. A comparison of the filtration results shows that insoluble watercolor pigments are too large to pass the pores of the membrane and are successfully rejected by the membrane, whereas the food coloring is completely soluble in water and easily passes the membrane. The laboratory experiment can be performed in a 2 h activity and serves the purpose of (1) exposing students to a new and interesting field of material science. It (2) makes them familiar with porous membranes for the production of safe drinking water and (3) introduces them to a template-removal technique utilizing acid/base theory. There were 52 advanced high school students and 55 high school teachers in Switzerland who already successfully performed the laboratory experiment and found the activity engaging and motivating

Indoor Air Purification Using Activated Carbon Adsorbers: Regeneration Using Catalytic Combustion of Intermediately Stored VOC

In this study, we demonstrate a two-step process where activated carbon based air purifier systems can be regenerated in situ and eliminate volatile organic compounds (VOCs) from indoor air in an energy efficient way. A carbon based adsorber was combined in series with a CeO₂/TiO₂ oxidative catalyst for total oxidation of the previously adsorbed and periodically released volatile organic compounds during regeneration runs. We investigated the adsorption and desorption behavior of five different VOCs (diethyl ether, limonene, linalool, hexanoic acid, triethylamine and <i>n</i>-decane) with thermogravimetric measurements, mass spectrometry and elemental analysis. Cyclic loading and regeneration experiments were carried out with selected VOCs (limonene, linalool and <i>n</i>-decane) for testing regeneration at elevated temperature. We showed that in situ thermal regeneration and subsequent oxidation of released VOC is a sustainable and easy applicable technology for indoor air purification. This two-step approach allows energy saving as the VOCs are eliminated discontinuously (enriching VOCs; periodic catalytic combustion), and is of high environmental and economic interest, as much less maintenance services are required

Rapid Production of a Porous Cellulose Acetate Membrane for Water Filtration using Readily Available Chemicals

A chemistry laboratory experiment using everyday items and readily available chemicals is described to introduce advanced high school students and undergraduate college students to porous polymer membranes. In a three-step manufacturing process, a membrane is produced at room temperature. The filtration principle of the membrane is then illustrated by filtering solutions containing pigmentary watercolor or food coloring. A comparison of the filtration results shows that insoluble watercolor pigments are too large to pass the pores of the membrane and are successfully rejected by the membrane, whereas the food coloring is completely soluble in water and easily passes the membrane. The laboratory experiment can be performed in a 2 h activity and serves the purpose of (1) exposing students to a new and interesting field of material science. It (2) makes them familiar with porous membranes for the production of safe drinking water and (3) introduces them to a template-removal technique utilizing acid/base theory. There were 52 advanced high school students and 55 high school teachers in Switzerland who already successfully performed the laboratory experiment and found the activity engaging and motivating

MOF Channels within Porous Polymer Film: Flexible, Self-Supporting ZIF‑8 Poly(ether sulfone) Composite Membrane

Polymer - metal organic framework (MOF) composite membranes are promising materials for gas separation and could be potentially applied within many industrial applications. However, key limitations of currently reported layered MOF-polymer composites are their lack of scalability and mechanical stability. A big challenge for synthesis of such composites is directing the growth of homogeneous, defect-free MOF crystal layers. Here, a membrane synthesis method allowing the formation of flexible, noncontinuous zeolitic imidazolate framework 8 (ZIF-8) – poly­(ether sulfone) (PES) composite membranes is presented. The ZIF-8 growth is restricted to the PES pores by exploiting directed ZnO seed-nanoparticles. The seeding process is part of the membrane formation process itself and allows for specifically integrating ZnO within polymeric membranes enabling easy and scalable control of the MOF-crystal formation. During solvent casting and membrane formation, a phase separation process allows trapping ZnO seed-nanoparticles within bicontinuous PES pores. Because of ZnO serving in parallel as seed and zinc source, ZIF formation can be induced and controlled by adding only one solution containing the organic linker. This ZnO nanoparticle seeding technique enables a pore-specific <i>in situ</i> growth of small (<5 μm in diameter) ZIF-8 islands via solvothermal synthesis. This leads to mechanically flexible self-supporting ZIF-8 membranes exhibiting gas selectivities of 9.3 ± 3.1 (H₂/CO₂) and 11.5 ± 2.1 (H₂/N₂)

Simulated soft tissue (gelatin) with two dental implants.

<p>The anode (top, left) and cathode (top, right) were connected as part of an electric circuit powered by an external controller (top). The most probable reactions occurring at the electrodes are displayed in a scheme of the electrolysis setup to further illustrate the process (middle) and an overview (below) of the most likely occurring reactions is shown, too (adapted from <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0016157#pone.0016157-MartinezHuitle1" target="_blank">[8]</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0016157#pone.0016157-Urano1" target="_blank">[19]</a>).</p

Proof of pH changes during electrochemical implant treatment.

<p>Photographic images of dental implants in simulated soft tissue using pH-sensitive dyes to visualize local pH changes. The dark blue color for thymol blue indicated a pH above 9 (alkaline) while the pink color confirmed a pH below 3 (strongly acidic). Confirmation with a second pH-sensitive dye, bromocresol green allowed mapping a similar acidic pH at the anode. For both dyes, a homogenous, circular simulated soft tissue section of high/low pH evolved around the implant insertion hole.</p

Magnetically Recoverable, Thermostable, Hydrophobic DNA/Silica Encapsulates and Their Application as Invisible Oil Tags

A method to encapsulate DNA in heat-resistant and inert magnetic particles was developed. An inexpensive synthesis technique based on co-precipitation was utilized to produce Fe₂O₃ nanoparticles, which were further functionalized with ammonium groups. DNA was adsorbed on this magnetic support, and the DNA/magnet nanocluster was surface coated with a dense silica layer by sol–gel chemistry. The materials were further surface modified with hexyl­trimethoxy­silane to achieve particle dispersibility in hydrophobic liquids. The hydrodynamic particle sizes were evaluated by analytical disc centrifugation, and the magnetic properties were investigated by vibrating sample magnetometry. The obtained nanoengineered encapsulates showed good dispersion abilities in various nonaqueous fluids and did not affect the optical properties of the hydrophobic dispersant when present at concentrations lower than 10³ μg/L. Upon magnetic separation and particle dissolution, the DNA could be recovered unharmed and was analyzed by quantitative real-time PCR and Sanger sequencing. DNA encapsulated within the magnetic particles was stable for 2 years in decalin at room temperature, and the stability was further tested at elevated temperatures. The new magnetic DNA/silica encapsulates were utilized to developed a low-cost platform for the tracing/tagging of oils and oil-derived products, requiring 1 μg/L = 1 ppb levels of the taggant and allowing quantification of taggant concentration on a logarithmic scale. The procedure was tested for the barcoding of a fuel (gasoline), a cosmetic oil (bergamot oil), and a food grade oil (extra virgin olive oil), being able to verify the authenticity of the products

Reduction of <i>E. Coli</i> adhered on dental implants.

<p>Viable <i>E. coli</i> counts were reduced on implants after current treatment for 15 minutes (mean log₁₀ CFU (colony-forming units) values (N = 3) and standard deviation). Pronounced differences arised for anodic (oxidative environment) and cathodic (alkaline environment) implants. A full disinfection could be obtained if an implant was used as anode and at a current of at least 7.5 mA. Same capital letters above data sets indicate no statistically significance (p>0.05).</p