Thickening, dewatering and disposal of coagulation sludges from surface water treatment plant

Työssä tutkittiin Kyrönjoen jokiveden kemiallisessa saostuksessa muodostuvan rautapitoisen lietteen kunnostusta, tiivistystä, vedenerotusta ja loppusijoitusta. Lietteen kunnostusta ja tiivistystä tutkittiin nonionisella ja anionisella polymeerillä laskeutus- ja suodatuskokeissa. Vedenerotuskokeet toteutettiin kammiosuotopuristimella. Liete- ja suodosnäytteistä analysoitiin muun muassa kiintoaineen, metallien, ravinteiden ja orgaanisen aineen määrä. Eri loppusijoitusten soveltuvuutta arvioitiin lietteen ominaisuuksien perusteella. Vuosittaisia lietemääriä arvioitiin jokiveden ominaisuuksien ja kemiallisen saostuksen tilastojen perusteella. Kokeissa todettiin nonionisen polymeerin soveltuvan paremmin lietteen kunnostukseen alhaisemman optimiannostuksen vuoksi. Liete tiivistyi laskeutuskokeissa 1 % kiintoainepitoisuuteen. Tiivistyksen supernatantti oli pitoisuuksiltaan verrattavissa jokiveteen. Kammiosuotopuristimella käsitellyn lietteen kuiva-ainepitoisuus oli suurimmillaan 11,7 %. Optimoitu kammiosuotopuristin muodostaa todennäköisesti kuivemman lietteen. Laboratoriolingolla päästiin 16 % (±2) kuiva-ainepitoisuuteen. Orgaanista ainetta lietteissä oli 57,2 – 63,7 %. Lietteen kuiva-aineen metallipitoisuudet olivat alle maa- ja metsätalousministeriön lannoitevalmisteasetuksen raja-arvojen. Kemiallisessa saostuksessa kiintoainetta muodostuu arviolta 225 – 406 t/a. Kiintoainepitoisuudeltaan 15 – 20 % lietettä muodostuu arviolta 1125 – 2710 t/a. Lietteenkäsittelyksi esitetään tiivistystä ja mekaanista vedenerotusta lingolla. Kunnostukseen esitetään nonionista polymeeriä. Vedenerotuksen rejektivedet voidaan johtaa tiivistykseen ja tiivistyksen rejektivedet voidaan mahdollisesti johtaa jokeen tai kemialliseen saostukseen. Loppusijoituksena lietteelle esitetään maanparannuskäyttöä. Liete voidaan sekoittaa turpeeseen tai kompostimultaan pH:n ja kosteuden säätämiseksi. Lisätutkimuksina suositellaan tiivistyksen kuormituksen ja lingon koeajoja

Oxygen and nitrogen plasma hydrophilization and hydrophobic recovery of polymers

Plasma hydrophilization and subsequent hydrophobic recovery are studied for ten different polymers of microfabrication interest: polydimethylsiloxane (PDMS), polymethylmethacrylate, polycarbonate, polyethylene, polypropylene, polystyrene, epoxy polymer SU-8, hybrid polymer ORMOCOMP, polycaprolactone, and polycaprolactone/D,L-lactide (P(CL/DLLA)). All polymers are treated identically with oxygen and nitrogen plasmas, in order to make comparisons between polymers as easy as possible. The primary measured parameter is the contact angle, which was measured on all polymers for more than 100 days in order to determine the kinetics of the hydrophobic recovery for both dry stored and rewashed samples. Clear differences and trends are observed both between different polymers and between different plasma parameters.Peer reviewe

Inkjet Printed Silver Electrodes on Macroporous Paper for a Paper-Based Isoelectric Focusing Device

We demonstrate a combined printing process utilizing inkjet printing of silver electrodes and solid-ink technology for printing hydrophobic wax barriers for fabricating paper microfluidic devices with integrated electrodes. Optimized printing parameters are given for achieving conducting silver lines on the top of macroporous chromatography paper down to 250 mu m-300 mu m resolution. Electrical characterization and wicking experiments demonstrate that the printed silver patterns are simultaneously conductive and porous enough to allow reliable capillary wicking across the electrodes. The combined wax and silver printing method is used for fabrication of paper microfluidic isoelectric focusing devices for separation and concentration of proteins. Published by AIP Publishing.Peer reviewe

Water and Blood Repellent Flexible Tubes

A top-down scalable method to produce flexible water and blood repellent tubes is introduced. The method is based on replication of overhanging nanostructures from an aluminum tube template to polydimethylsiloxane (PDMS) via atomic layer deposition (ALD) assisted sacrificial etching. The nanostructured PDMS/titania tubes are superhydrophobic with water contact angles 163 +/- 1 degrees (advancing) and 157 +/- 1 degrees (receding) without any further coating. Droplets are able to slide through a 4 mm (inner diameter) tube with low sliding angles of less than 10 degrees for a 35 mu L droplet. The superhydrophobic tube shows up to 5,000 times increase in acceleration of a sliding droplet compared to a control tube depending on the inclination angle. Compared to a free falling droplet, the superhydrophobic tube reduced the acceleration by only 38.55%, as compared to a 99.99% reduction for a control tube. The superhydrophobic tubes are blood repellent. Blood droplets (35 mu L) roll through the tubes at 15 degrees sliding angles without leaving a bloodstain. The tube surface is resistant to adhesion of activated platelets unlike planar control titania and smooth PDMS surfaces.Peer reviewe

Elastic and fracture properties of free-standing amorphous ALD Al2O3 thin films measured with bulge test

We have investigated elastic and fracture properties of amorphous Al2O3 thin films deposited by atomic layer deposition (ALD) with bulge test technique using a free-standing thin film membrane and extended applicability of bulge test technique. Elastic modulus was determined to be 115 GPa for a 50 nm thick film and 170 GPa for a 15 nm thick film. Residual stress was 142 MPa in the 50 nm Al2O3 film while it was 116 MPa in the 15 nm Al2O3 film. Density was 3.11 g cm(-3) for the 50 nm film and 3.28 g cm(-3) for the 15 nm film. Fracture strength at 100 hPa s(-1) pressure ramp rate was 1.72 GPa for the 50 nm film while for the 15 nm film it was 4.21 GPa, almost 2.5-fold. Fracture strength was observed to be positively strain-rate dependent. Weibull moduli of these films were very high being around 50. The effective volume of a circular film in bulge test was determined from a FEM model enabling future comparison of fracture strength data between different techniques.Peer reviewe

A Microfluidic Chip Architecture Enabling a Hypoxic Microenvironment and Nitric Oxide Delivery in Cell Culture

A hypoxic (low oxygen level) microenvironment and nitric oxide paracrine signaling play important roles in the control of both biological and pathological cell responses. In this study, we present a microfluidic chip architecture for nitric oxide delivery under a hypoxic microenvironment in human embryonic kidney cells (HEK-293). The chip utilizes two separate, but interdigitated microfluidic channels. The hypoxic microenvironment was created by sodium sulfite as the oxygen scavenger in one of the channels. The nitric oxide microenvironment was created by sodium nitroprusside as the light-activated nitric oxide donor in the other channel. The solutions are separated from the cell culture by a 30 µm thick gas-permeable, but liquid-impermeable polydimethylsiloxane membrane. We show that the architecture is preliminarily feasible to define the gaseous microenvironment of a cell culture in the 100 µm and 1 mm length scales

A Microfluidic Chip Architecture Enabling a Hypoxic Microenvironment and Nitric Oxide Delivery in Cell Culture

A hypoxic (low oxygen level) microenvironment and nitric oxide paracrine signaling play important roles in the control of both biological and pathological cell responses. In this study, we present a microfluidic chip architecture for nitric oxide delivery under a hypoxic microenvironment in human embryonic kidney cells (HEK-293). The chip utilizes two separate, but interdigitated microfluidic channels. The hypoxic microenvironment was created by sodium sulfite as the oxygen scavenger in one of the channels. The nitric oxide microenvironment was created by sodium nitroprusside as the light-activated nitric oxide donor in the other channel. The solutions are separated from the cell culture by a 30 µm thick gas-permeable, but liquid-impermeable polydimethylsiloxane membrane. We show that the architecture is preliminarily feasible to define the gaseous microenvironment of a cell culture in the 100 µm and 1 mm length scales

Inkjet-printed flexible silver electrodes on thiol-enes

Flexible and conductive silver electrodes were fabricated by inkjet printing on several different compositions of thiol-ene polymers. Conductive electrodes with resistivity down to 30 ??cm and good adhesion of the electrodes were obtained by optimizing the printing parameters. The maximum printing resolution was 100 ?m lines and 80 ?m gaps between the lines. Printing on top of cross-linked off-stoichiometric thiol-ene polymer was tested for compositions ranging from 30 % thiol excess to 5 % allyl (?ene?) excess. The roughness off the thiol-ene surfaces was shown to greatly improve the quality of the printed electodes: consistently high yield of conductive electrodes was obtained on rough surfaces (roughness ?1 ?m), whereas on smooth surfaces the electrodes were often cracked. The lowest resistivity values were obtained on electrodes printed on near stoichiometric thiol-ene substrates. The conductivity of the electrodes was retained after 5 % linear strain and after repeated bending with 1 mm radius of curvature, showing the potential for flexible sensors. The electrodes were also applied to electrical impedance-based monitoring of cell growth on thiol-ene surfaces, which showcased that the electrodes survive stressed cell culture conditions for at least 36 h.Peer reviewe

MICRO FUEL CELL WITH LITHOGRAPHICALLY DEFINED FLOWFIELD CHANNELS AND RANDOM PATTERNS FOR GAS DIFFUSION LAYER

Abstract: We present a silicon microfabricated hydrogen micro fuel cell (MFC) with a proton-exchange membrane (PEM). The device has an integrated gas diffusion layer (GDL) using silicon nanograss (also known as black silicon), and the highly doped silicon wafer itself acts as a current conductor. The device is extremely straightforward to fabricate, requiring only three photolithographic steps. In addition to good manufacturability, further savings are obtained by replacing platinum with chromium on the electrodes. However, an unexpected behavior is experienced in its electro-chemical properties that lead to very fast degradation and a negative resistance region in the U/I plot

Surface Assisted Laser Desorption/Ionization on Two-Layered Amorphous Silicon Coated Hybrid Nanostructures

Matrix-free laser desorption/ionization was studied on two-layered sample plates consisting of a substrate and a thin film coating. The effect of the substrate material was studied by depositing thin films of amorphous silicon on top of silicon, silica, polymeric photoresist SU-8, and an inorganic-organic hybrid. Des-arg9-bradykinin signal intensity was used to evaluate the sample plates. Silica and hybrid substrates were found to give superior signals compared with silicon and SU-8 because of thermal insulation and compatibility with amorphous silicon deposition process. The effect of surface topography was studied by growing amorphous silicon on hybrid micro- and nanostructures, as well as planar hybrid. Compared with planar sample plates, micro- and nanostructures gave weaker and stronger signals, respectively. Different coating materials were tested by growing different thin film coatings on the same substrate. Good signals were obtained from titania and amorphous silicon coated sample plates, but not from alumina coated, silicon nitride coated, or uncoated sample plates. Overall, the strongest signals were obtained from oxygen plasma treated and amorphous silicon coated inorganic-organic hybrid, which was tested for peptide-, protein-, and drug molecule analysis. Peptides and drugs were analyzed with little interference at low masses, subfemtomole detection levels were achieved for des-arg9-bradykinin, and the sample plates were also suitable for ionization of small proteins