Integrated Time-to-Digital Converters Based on Interpolation

The main features of two time-to-digital convertersbased on interpolation are presented, together with some measurementresults. The first converter is based on digital delay line interpolatorsand has been implemented in a 1.2 µm CMOS process.It has a single-shot resolution of 1 ns (-value)and a nonlinearity less than ±50 ps in the measurementrange 5 to 500 ns. The power consumption of the circuit is 15mW. The second time digitizer has analog interpolators basedon time-to-voltage conversion and has been implemented in a 1.2 µm BiCMOS process. It has a single-shot resolutionof 50 ps and a nonlinearity less than 150 ps in the measurementrange 1 to 300 ns. The power consumption of this circuit is 200mW.     

Chemical and physical properties of short rotation tree species

The European Union’s growth strategy (Europe 2020) requires reductions in greenhouse gas (GHG) emissions and increases in both renewable energy sources and energy efficiency. Short rotation forestry (SRF) has achieved greater awareness due to these targets. Short rotations (1–12 years), rapid growth and the ability to coppice are typical for SRF. Salix, Populus, Alnus and Betula have smaller GHG emissions of biomass production than annual agricultural plant species, since management and harvesting are not needed every year. Physicochemical properties of these species must be known when their utilisation is planned and optimised. Seven tree species were studied: three willows (Salix myrsinifolia, Salix schwerinii and Klara), one aspen (Populus tremula), one alder (Alnus glutinosa) and two birches (Betula pendula and Betula pubescens). One stem wood (S) sample and one stem wood and bark (SB) sample of each tree were investigated. Furthermore, seven surface soil samples and four incineration ash samples (two S. myrsinifolia and two S. schwerinii) were also studied. Heating values, densities, ash contents as well as carbon, hydrogen and nitrogen contents of all short rotation biomass samples were usually quite typical for the corresponding tree species. Additional observations included the accumulation of cadmium in willow and aspen samples, small chloride content values, and higher ash- and element contents in SB samples than in the corresponding S samples. Nutrient content of ash was usually higher in the S sample, contradictory to biomass samples, and finally the cadmium content of the ash samples was very high.     

制浆造纸行业节能型真空系统——Ecopump节能透平机

通过与制浆造纸行业现有的液环泵和单/多级透平风机两种真空系统进行比较,介绍了芬兰Ecopump节能透平机真空系统技术及其优势所在。Ecopump节能透平机可为纸机真空系统节能30%~70%,同时具有投资回报快、安装维护快且简单等特点。     

Total hordatine content in different types of beers

Hordatines are phenolic secondary metabolites typical of barley. Hordatines withstand at least moderate processing, and thus they are also found in barley malts and beer. So far, no published data on the hordatine content has been available in beers or different styles of beer. The aim of this study was to produce information on the total hordatine content in beers and statistically compare the hordatine content of different beer types. In the current study, hordatines were analysed in 208 beers by high‐performance liquid chromatography equipped with a diode array detector (HPLC‐DAD). The average total hordatine content of all beer samples was 5.6 ± 3.1 mg L^?1 as p‐coumaric acid equivalents (PCAE), with a minimum values 0 to a maximum value 18.7 mg L^?1 PCAE. The total hordatine content correlated positively to the alcohol content in lagers, ales, stouts and porters, but not in wheat beers. There was no statistically significant difference in hordatine content in different types of beer, excluding the non‐alcoholic group of beers. It is noteworthy that non‐alcoholic beers also contained hordatines. More research would be needed to understand how parameters, such as mashing, should be chosen in order to achieve maximum recovery of hordatines in wort and beer.     

Determination of the sources of indoor PM2.5 in Amsterdam and Helsinki

Daily PM2.5 samples were repeatedly collected (1-8 times) in the homes of elderly nonsmoking individuals with coronary heart disease in Amsterdam, The Netherlands (33 individuals) and Helsinki, Finland (44 individuals). Sources of indoor PM2.5 were evaluated using a two-way multilinear engine model. Because the indoor elemental data lacked a traffic marker, separation of traffic related PM was attempted by combining the indoor data with fixed site outdoor data that also contained NO. Six outdoor sources, including long-range transport (LRT), urban mixture, oil combustion, traffic, sea-salt, and soil were identified, and three indoor sources were resolved: resuspension, potassium-rich and copper-rich sources. The average contribution of the indoor factors was 6% (1.1 microg m(-3)) and 22% (2.4 microg m(-3)) in Amsterdam and Helsinki, respectively. The highest longitudinal correlations between source-specific outdoor and indoor PM2.5 concentrations were found for LRT and urban mixture; the median R was above 0.6 for most sources. The longitudinal correlations were lower in Helsinki than in Amsterdam. Indoor-generated PM2.5 was not related to ambient concentrations. We conclude that using outdoor and indoor data together improved the source apportionment of indoor PM2.5. The results support the use of fixed site outdoor measurements in epidemiological time-series studies on outdoor air pollution.     

Synergism of enzymes in chemical pulp bleaching from an industrial point of view: A critical review

Enzymes are biological catalysts and are very specific, catalyzing either a single chemical reaction or a limited number of closely related reactions. For example, xylanases are enzymes that catalyze the cleavage of polymeric xylan and thereby break down this hemicellulose. The first xylanase enzyme preparations used in the bleaching process of chemical pulp also contained cellulase, which catalyzes the hydrolysis of cellulose. This obviously had an adverse effect on pulp yield and quality. Unfortunately, this setback gave enzyme-assisted pulp bleaching a negative reputation. At a later stage, enzyme producers managed to engineer enzyme production strains that generated cellulase-free xylanase preparations. However, due to the initial negative experiences with the earlier enzyme mixtures, only a limited number of companies in the pulp industry have seriously considered using these so-called second-generation enzymes in their bleach plants. It is apparent that these improved enzyme preparations would bring about significant benefits in terms of chemical cost savings and effluent quality. In addition to xylanase-aided bleaching, it is possible to improve the effectivity further by adding other enzymes, such as lipase and esterase, to create an enzyme cocktail. This may be particularly beneficial in the bleaching of hardwood pulp, such as white birch, which often encounters complex and troublesome problems with wood extractives. By adding different types of enzymes at more than one position in the fiberline, even further improvements are possible. The main objective of this review is to discuss the advantages of incorporating modern enzyme preparations in the bleaching of chemical pulp.     

Poly(propylene) composite with hybrid nanofiller: Dynamic properties

Mechanical, impact, and relaxation properties of in situ synthesized carbon nanotubes‐polyaniline (CNT‐PANi) hybrid nanoparticle‐filled poly(propylene) (PP) composites with or without an amphiphilic dispersing agent were investigated using tensile testing, notched Charpy impact testing, and dynamical mechanical testing methods. The reference material was MWCNT filled PP composite. Ethyl gallate (EG) was the dispersing agent which realizes high conductivity in PP composites with hybrid filler. Measured properties showed quite similar behavior of CNT‐PANi hybrid and neat CNT filled composites. Addition of 20% EG in PP did not cause essential differences compared to the neat PP. When the dispersing agent was added in filler containing PP composites, remarkable effects were observed, especially in PP‐hybrid composites. Mechanically, these materials had improved tensile properties, but they were brittle compared to the materials without dispersing agent. Dynamic mechanical analysis showed improvement in storage modulus, and in loss modulus the α transition was well observable. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Measurement of Particulate Carbon in Atmospheric Aerosol in Helsinki

By means of a simple optical apparatus the levels and variations of concentrations of elemental carbon in particles were measured. Additionally, relations between variations of elemental carbon, lead, sulfate, total suspended particle, and nitrate concentrations were studied. Calibration was performed on real samples analyzed by a wet chemical method.     

Kinetics of glucose decomposition in formic acid

Cellulose is abundantly available in the form of forestry and agricultural lignocellulosic residues. These residues offer the most potential source for the production of cellulosic glucose, which is a prerequisite for the sustainable production of glucose-based fuels and chemicals. Acid catalysis is one path to lignocellulosic glucose and further to its dehydration end products. Furthermore, many studied lignocellulose pretreatment methods for enzymatic hydrolysis are carried out in acidic conditions, in which the unwanted release of hemicellulose-based glucose and its further reactions to harmful end products are possible. Thus, in order to maximize glucose production from non-food cellulosic raw materials, data on the kinetics of cellulose decomposition and formation rates of end products are required. Glucose decomposition is a complex reaction system that has often been modelled with empirical, simplified models. In this study, a kinetic model was developed for glucose decomposition in formic acid solution. The experimentation was carried out in batch reactors at 180-220 °C in 5-20% (w/w) formic acid. The model developed relies on a mechanistic step through an unknown substance and gives excellent correspondence to the experimental data despite the pseudo-elementary nature of the model structure.