Application of a multiline material characterization method to inkjet printed electronics

Material characterization has become increasingly important with the adoption of simulation‐based workflow for microwave electronics design. This article focuses on the characterization of printable electronics materials using transmission‐line measurements and demonstrates the capability of the multiline characterization method to separate dielectric and conductor losses when line geometry and material properties vary between the lines. The effects of multiline algorithm, number of line standards, and methods for selecting optimal line lengths are demonstrated. Consistent characterization results are obtained from inkjet‐printed transmission lines on two different substrate materials. In addition, local conductor thickness variations are demonstrated as an effective way to decrease losses. Finally, the simulation‐based procedure for determining the material properties is outlined and applied to printable electronics characterization. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:177–183, 2014.     

Water quality in the southern Tibetan Plateau: chemical evaluation of the Yarlung Tsangpo (Brahmaputra)

Yarlung Tsangpo (Brahmaputra) is the largest river system draining the northern slopes of the Himalayan ranges on the southern Tibetan Plateau. It remains one of only two large non‐regulated rivers in China. In this paper the chemical composition of Yarlung Tsangpo and its major tributaries (Raga Tsangpo, Nyangchu and Lhasa River) are studied. Water samples (n = 55) were collected and measured for major ions, trace elements and nutrients in order to: (1) define the present chemical quality of this water course; (2) address possible mechanisms governing the water chemical compositions, and (3) identify potential sources for contaminants. Multivariable analysis shows that geology and climate are the major explanatory variables for the spatial variation in water chemistry in this river system. In general, water chemistry is mainly controlled by carbonate weathering, with Ca²⁺ and HCO being the dominant ions. In addition, runoff from brackish/saline lakes and geothermal waters, enriched in Na⁺, Cl^?, SO, Mg²⁺ and Li, are major contributors of elevated concentrations of these solutes in the headwater regions resulting in a relatively high loading of total dissolved solids (TDS, 146–397 mg L^?1). Levels of most heavy metals and total dissolved nutrients were generally found to be low. However, elevated As concentration (avg. 95 μg L^?1) in the headwaters and additions from untreated wastewater were evident at some locations. Copyright © 2009 John Wiley & Sons, Ltd.     

“Plug-up”–a new concept for fabricating SOI MEMS devices

This paper reports a novel process sequence for fabricating micromechanical devices on silicon-on-insulator (SOI) wafers. Among the merits of the described process are its improved immunity to stiction and elimination of conductor metal endurance problems during sacrificial etching in hydrofluoric acid. With this novel process one can controllably embed vacuum cavities within SOI substrates. Further processing of such cavity wafers enables realization of a wide variety of micromechanical devices based on single crystalline silicon or even integrated read-out circuitry.K. Järvi and T. Häkkinen are gratefully acknowledged for the device fabrication. The Finnish National Technology Agency, Okmetic, VTI Technologies, and Micro Analog Systems participated in funding this work. The ultrasonic devices were fabricated in collaboration with Autotank, Oras, Suunto, Vaisala, and Enermet.     

A new table for work with a microscope, a solution to ergonomic problems

Microscope workers are exposed to continuous static muscular work and an increased risk of musculoskeletal disorders in the neck, shoulder and upper extremities. In a Finnish research centre, microscope workers reported pain in the shoulder, neck, lower back and upper back. As a consequence, a programme to solve the ergonomic problems of microscope work was initiated and led to the construction of a new table for microscopes. Ten experienced male microscope workers were chosen as subjects to carry out an experimental study in which the new table and an old one, an ordinary non-adjustable laboratory table, were compared in a standardized microscope task. The dependent variable was the electromyographic activity measured from muscles in the neck–shoulder region. The new table allowed the microscope to be used with the head in an upright position, the forearms supported and with less flexion of the upper arm. Surface electromyographic measurements also confirmed that the changes were ergonomic improvements.     

Electro ultrasonic remediation of polycyclic aromatic hydrocarbons from contaminated soil

The polycyclic aromatic hydrocarbons (PAHs) with high molecular mass are renown for their high persistence in the soil, hydrophobic and toxicity. Remediation of these pollutants is still an unsolved task and needs more researches to be performed. The coupling of electrokinetics (EK) with ultrasonic energy (US) has advantages on desorbing and migrating PAHs from contaminated soil. US and EK work together to destroy PAHs. The objective of this study was to treat PAHs contaminated soil by using EK and ultrasonication. The contaminated oil contained about 100 mg kg⁻¹ chrysene. Experiments with US, EK and combined EK and ultrasound were conducted in reactors and pans with and without iron anodes. Results indicated that the removal was more effective with lower concentrations of chrysene. The average removal was better in experiment with combined EK and ultrasound using iron anode. This might be due to increase in electroconductivity by iron ions.     

Biodegradation of novel amino acid derivatives suitable for complexing agents in pulp bleaching applications

The biodegradability of four novel diethanolamine derivative complexing agents was examined by using two biodegradation tests standardised by OECD (301B and 301F). Ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA) were employed as reference substances. Biodegradation of the new complexing agents was studied both with unacclimated and acclimated inocula as well as by simulating wastewater treatment in sequencing batch reactors (SBRs). These new complexing agents were of technical grade, and therefore, the results are only indicative but these new compounds hold promise for use as complexing agents in the pulp and paper industry.The novel complexing agents were not readily biodegradable but they showed slight biodegradation. Around 10-30% degradation was found in the SBR where degradation was followed by measurement of concentration. Moreover the novel complexing agents did not have any negative impact on reactor performance as measured by chemical oxygen demand reduction. In the standardised biodegradation tests at best around 50% degradation was observed with the acclimated inoculum and in the prolonged test whereas EDTA and DTPA exhibited no biodegradation. The elevated degradation in acclimated sludge indicates that the water treatment plant microbes are capable of decomposing these molecules under favourable conditions. The total concentration of novel complexing agents decreased slightly during biodegradation tests, while the EDTA and DTPA concentrations remained stable.     

Physicochemical characterization of sahti,an ‘ancient’ beer style indigenous to Finland

Sahti, a strong, unhopped farmhouse beer flavoured with juniper, is still actively brewed in rural areas in Finland. Presented here is the first comprehensive analysis of the physical and chemical properties of this unique beer style. Twelve sahti samples from the southwest of Finland were analysed and, while properties varied, the beers generally had high levels of alcohol (mean = 7.9% ABV) and high residual extract (mean = 9.5°P). Foam stability was negligible, as is typical for the style, and glycerol concentrations at 3.1 – 4.7 g L^?1 were higher than in reference beers (commercial lager, wheat beer and porter). These features may be attributed to the very high gravity conditions employed in brewing sahti beers. Bitterness levels were relatively low (3–13 IBU) owing to the absence or moderate use of hops. All samples contained detectable levels of the clove‐like compound 4‐vinylguaiacol owing to the use of baker's rather than brewer's yeast for brewing. Concentrations of higher alcohols and esters were high, with many individual aroma compounds being above the normal flavour thresholds. Results have highlighted the uniqueness of this style of beer in comparison to commercially available beers and have contributed to our understanding of the reasons for the particular sensorial properties of this traditional beer style. Copyright © 2015 The Institute of Brewing & Distilling     

Decomposition of beta-alaninediacetic acid and diethylenetriamine-pentaacetic acid by hydrogen peroxide in alkaline conditions

The chemical decompositions of beta-alaninediacetic acid (ADA) and diethylenetriaminepentaacetic acid (DTPA) were studied in a pilot-plant flow-through system simulating alkaline (pH 10-11) hydrogen peroxide bleaching environments. The amount of hydrogen peroxide decomposition was evaluated, and the distribution calculation was performed. Under the conditions investigated, ADA was more degradable than DTPA (average residual 71% vs 94%). The decomposition of hydrogen peroxide was not dependent on the chelate; the residual percent of hydrogen peroxide was 40 in both cases.