Muscular,cardiorespiratory and thermal strain of mast and pole workers

This field study evaluated the level of muscular, cardiorespiratory and thermal strain of mast and pole workers. We measured the muscular strain using electromyography (EMG), expressed as a percentage in relation to maximal EMG activity (%MEMG). Oxygen consumption (VO₂) was indirectly estimated from HR measured during work and expressed as a percentage of maximum VO₂ (%VO₂max). Skin and deep body temperatures were measured to quantify thermal strain. The highest average muscular strain was found in the wrist flexor (24 ± 1.5%MEMG) and extensor (21 ± 1.0%MEMG) muscles, exceeding the recommendation of 14%MEMG. Average cardiorespiratory strain was 48 ± 3%VO₂max. Nearly half (40%) of the participants exceeded the recommended 50%VO₂max level. The core body temperature varied between 36.8°C and 37.6°C and mean skin temperature between 28.6°C and 33.4°C indicating possible occasional superficial cooling. Both muscular and cardiorespiratory strain may pose a risk of local and systemic overloading and thus reduced work efficiency. Thermal strain remained at a tolerable level.     

Lanthanide and Heavy Metal Free Long White Persistent Luminescence from Ti Doped Li–Hackmanite: A Versatile,Low‐Cost Material

Persistent luminescence (PeL) materials are used in everyday glow‐in‐the‐dark applications and they show high potential for, e.g., medical imaging, night‐vision surveillance, and enhancement of solar cells. However, the best performing materials contain rare earths and/or other heavy metal and expensive elements such as Ga and Ge, increasing the production costs. Here, (Li,Na)₈Al₆Si₆O₂₄(Cl,S)₂:Ti, a heavy‐metal‐ and rare‐earth‐free low‐cost material is presented. It can give white PeL that stays 7 h above the 0.3 mcd m^?2 limit and is observable for more than 100 h with a spectrometer. This is a record‐long duration for white PeL and visible PeL without rare earths. The material has great potential to be applied in white light emitting devices (LEDs) combined with self‐sustained night vision using only a single phosphor. The material also exhibits PeL in aqueous suspensions and is capable of showing easily detectable photoluminescence even in nanomolar concentrations, indicating potential for use as a diagnostic marker. Because it is excitable with sunlight, this material is expected to additionally be well‐suited for outdoor applications.     

Lignin‐xylaric acid‐polyurethane‐based polymer network systems: Preparation and characterization

Polyurethanes (PU) were synthesized from lignin by first preparing a prepolymer from esterified sugar‐based trihydroxyl compound xylaric acid and a 20 mol % excess of methylene diphenyl diisocyanate. The prepolymer was crosslinked with 5, 10, and 15 wt % of an industrial soda lignin, and polyethylene glycol was used to bring soft segments into the material structure. The total amount of bio‐based starting materials was as high as 35%. Evidence for the reaction between the prepolymer and lignin was observed using Fourier transform infrared spectroscopic analysis and ¹³C nuclear magnetic resonance spectroscopy. The thermal properties of the materials were investigated by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). The mechanical and viscoelastic properties of the materials were determined by dynamic mechanical analysis (DMA). The glass transition temperatures (T_g) obtained from DSC and DMA showed a trend of increasing T_g with the increasing amount of lignin. A similar trend was observed with TGA for the increasing thermal stability up to 550^oC with the increasing amount of lignin. The lignin‐polyurethanes obtained were stiff materials showing high Young's modulus values. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39714.     

Trends in hydrometeorological conditions and stream water organic carbon in boreal forested catchments

Temporal trends in stream water total organic carbon (TOC) concentration and export were studied in 8 forested headwater catchments situated in eastern Finland. The Seasonal Kendall test was conducted to identify the trends and a mixed model regression analysis was used to describe how catchment characteristics and hydrometeorological variables (e.g. precipitation, air and stream water temperatures, and atmospheric deposition) related to the variation in the concentration and export of stream water TOC. The 8 catchments varied in size from 29 to 494 ha and in the proportion of peatland they contained, from 8 to 70%. Runoff and TOC concentration were monitored for 15-29 years (1979-2006). Trends and variation in TOC levels were analysed from annual and seasonal time series. Mean annual TOC concentration increased significantly in seven of the eight catchments. The trends were the strongest in spring and most apparent during the last decade of the study period. The slopes of the trends were generally smaller than the variation in TOC concentration between years and seasons and between catchments. The annual TOC export showed no clear trends and values were largely determined by the temporal variability in runoff. Annual runoff showed a decreasing trend in two of the eight catchments. Mean annual air and stream water temperatures showed increasing trends, most clearly seen in the summer and autumn series. According to our modeling results, stream water temperature, precipitation and peatland percentage were the most important variables explaining annual and most seasonal TOC concentrations. The atmospheric deposition of SO₄, NH₄, and NO₃ decreased significantly over the study period, but no significant link with TOC concentration was found. Precipitation was the main hydrometeorological driver of the TOC export. We concluded that stream water TOC concentrations and exports are mainly driven by catchment characteristics and hydrometeorological factors rather than trends in atmospheric acid deposition.     

IR-sintering of ink-jet printed metal-nanoparticles on paper

Sintering of printed metal nanoparticles can be made not only by conventional heating, but also by, e.g., electrical, microwave, plasma, laser and flash lamp annealing. We demonstrate sintering by using low-cost incandescent lamps as an effective way of obtaining highly conductive contacts of two types of ink-jet printed metal-nanoparticle inks on paper; both alkanethiol protected gold nanoparticles and a commercially available silver nanoparticle ink. This low-cost roll-to-roll compatible sintering process is especially suitable on paper substrates because of the high diffuse reflectance, relatively high thermal stability and low thermal conductivity of paper. A volume resistivity of around 10 μΩ cm was achieved of the inkjetted silver nanoparticles within 15 s of exposure to an IR lamp, which corresponds to a conductivity of 10-20% of that of bulk silver. Too long exposure time and too high intensity, however, lead to darkening of the paper fibers. Both the crack formation and the coffee ring effect of the inkjet printed gold nanoparticles were, furthermore, found to be reduced on paper as compared to glass or plastic substrates.     

Synthesis of ZnO tetrapods for flexible and transparent UV sensors

ZnO tetrapods (ZnO-Ts) were synthesized in a vertical flow reactor by gas phase oxidation of Zn vapor in an air atmosphere. The morphology of the product was varied from nearly spherical nanoparticles to ZnO-Ts, together with the partial pressure of Zn and reaction temperature. MgO introduced during synthesis, increased the band gap, the optical transparency in the visible range, and also changed the ZnO-T structure. Fabricated flexible transparent UV sensors showed a 45-fold current increase under UV irradiation with an intensity of 30 μW cm(-2) at a wavelength of 365 nm and response time of 0.9 s.     

Heat and Mass Transfer Analogy Studies of Binary Liquid Mixture in Comparison with Eteanol-n-Heptane Evaporating to Air

ABSTRACT

An expenmental and theoretical study of heat and mass transfer analogy and a comparison of that to a binary liquid mixture evaporation is presented. Common organic solvents, ethanol and n-heptane, were used to form an alcohol - hydrocarbon mixture. Studies were carried out in a horizontal rectangular channel having air flow velocities of 0.2 – 0.9 m/s. Heat transfer coefficients were measured with a copper plate resistor and mass transfer coefficients with a square pool. The heat and mass transfer analogy is presented for a system having two evaporating compounds with a fixed value of air flow and verified by measuring and comparing mass transfer coefficients for distilled water with air flow velocities of 0.2 - 0.9 mls. An illustrative example of the use of the theory for industrial ventilation is presented.     

Effects of Silage Fermentation and Post-ruminal Casein Supplementation in Lactating Dairy Cows: 2—Energy Metabolites and Plasma Amino Acids

Four cows were used in a 4×4 Latin square design with a 2×2 factorial arrangement of treatments to examine the effects of the extent of silage fermentation and post-ruminal casein infusion on the arterial concentrations and mammary arterial–venous (A–V) difference of energy-yielding nutrients and plasma amino acids. Of the two silages one was preserved with formic acid (FA-silage) and the other with an inoculant of lactic acid bacteria (LAB-silage). Both silages were given ad libitum with 8 kg day^-1 of barley, without or with duodenal casein infusing (400 g day^-1). Blood was sampled from the coccygeal vessel and milk vein. FA-silage less fermented than LAB-silage as indicated by higher concentration (g kg^-1 dry matter) of water soluble carbohydrates (178 vs 68) and lower concentration of lactic acid (32 vs 147). Plasma concentration of glucose was lower (P<0·05) and concentrations of essential amino acids (P<0·001) and blood β-hydroxybutyrate (BHB) (P<0·01) were higher with FA-silage than with LAB-silage. There was a strong linear relationship between arterial concentration and mammary A–V difference of blood metabolites, except BHB, and amino acids. The relationship between arterial concentration and mammary A–V difference of glucose was different between the silages. Mammary extraction rates of glucose, BHB, histidine, leucine and lysine were affected by their arterial concentrations. The interaction between silage fermentation and casein infusion was significant (P<0·05) in arterial concentration of branched-chain amino acids, the increase being greater with FA-silage than with LAB-silage. The results suggest that the supply of glucose may limit milk synthesis in cows given restrictively fermented grass silage and barley, whereas the supply of amino acids may be more limiting with extensively fermented silages. It is further suggested that the mammary gland has a capacity to adapt it's efficiency of nutrient uptake according to the supply and mammary demand of nutrients. © 1997 SCI.     

Synthesis,characterization and crosslinking of functional star‐shaped poly(ε‐caprolactone)

Star‐shaped low molecular weight poly(ε‐caprolactone)s (PCLs) were synthesized and functionalized with crosslinkable terminal groups for subsequent crosslinking. The ε‐caprolactone (CL) prepolymers were polymerized by ring‐opening in the presence of polyglycerine (PGL) as an initiator (1, 3 and 5 mol%) and Sn(II)2‐ethylhexanoate as a catalyst. Characterization of the prepolymer by ¹³C/¹H nuclear magnetic resonance (NMR) spectroscopy, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) revealed a six‐armed star‐shaped structure for the prepolymer with the molecular weight controlled by the ratio of PGL and CL. Functionalization of the hydroxyl‐terminated prepolymer was carried out with maleic or itaconic anhydride. In both cases, the characterization of the functionalized prepolymer showed that the hydroxyl groups were completely substituted. The functionalized PCLs were successfully crosslinked through the reaction of double bonds. The crosslinking was induced either thermally with organic peroxide or photochemically with a photosensitive initiator. Characterization of the crosslinked PCLs by Soxhlet extraction, DSC and FTIR showed that the itaconic double bond was much more reactive in thermal crosslinking than the maleic double bond. Thus, the crosslinked prepolymers that were functionalized with itaconic double bonds achieved a gel content of about 90%. A gel content of 100% was achieved with several compositions where crosslinking agents were employed. © 2002 Society of Chemical Industry