The physical demands upon (Dutch) fire-fighters in relation to the maximum acceptable energetic workload

The aim of this study was to assess the tasks and activities that make physical demands on Dutch fire-fighters and to compare them with a guideline related to the development of excessive fatigue. The occupational physical demands on Dutch fire-fighters were assessed by conducting a task analysis during 85 24-h shifts. While workplace observations on the duration and frequency of physical tasks and activities were recorded, the heart rate was measured. This was then used to calculate the heart rate reserve percentage (%HRR) for predefined working periods, tasks and activities during 24-h shifts. The findings indicate that actual fire-fighting during 24-h shifts is characterised by a low frequency of incidents, a short ‘turn-out’ time, short tasks, and activities with a moderate to occasionally high energetic workload. Two tasks which sometimes occur in actual fire-fighting exceeded the guideline on energetic workload. The conclusion was that, though the number of incidents and the occupational demands are low during 24-h shifts, the peak loads for these two tasks are energetically high and could lead to excessive fatigue. Consequently, attention may need to be paid to health surveillance for persons exposed to such energetic peak loads, the development of physical and medical selection procedures, training, and workplace adjustments.     

Improvement of corrosion protection offered to galvanized steel by incorporation of lanthanide modified nanoclays in silane layer

Silane sol–gel based films are very promising alternatives to the traditional chromate pre-treatments. However, the protection offered by the silane films strongly decreases when the coating is damaged. Some previous studies showed that the barrier properties of the silane layer can be improved by incorporation of clay nanoparticles. Moreover, inhibitive metallic cations can be incorporated in the nanoclays by ion exchange, providing a way to prepare cheap corrosion inhibitors nanoreservoirs offering self-healing properties. Rare earth (RE) metal salts have been shown to be effective corrosion inhibitors on a wide range of metals, including hot dip galvanized (HDG) steel. For this study, montmorillonite clay is modified to obtain a Ce(III) montmorillonite clay (Ce-MMT). The amount of incorporated Ce(III) is characterized by means of XRF measurements. X-ray diffraction showed that the Ce(III) is located in the interlayer space.     

Corn grain-processing method interacts with calcium salts of palm fatty acids supplementation on milk production and energy balance of early-lactation cows grazing tropical pasture

The objective of our study was to investigate the associative effects of feeding Ca salts of palm fatty acids (FA) and corn grain-processing method on production, nutrient digestibility, energy balance, and carryover effects of early-lactation dairy cows grazing a tropical pasture. Treatment diets were offered from 3 to 16 wk postpartum (treatment period), in which all cows grazed elephant grass (Pennisetum purpureum L. Cameroon) and treatments were added to a concentrate supplement. Treatments were flint corn grain-processing method either as fine ground (FGC) or steam-flaked (SFC) associated with Ca salts of palm FA supplementation either not supplemented or supplemented (CSPO). From 17 to 40 wk postpartum (carryover period) all cows received a common diet fed as total mixed ration. During the treatment period, a tendency for an interaction between CSPO and corn grain-processing method were observed for milk yield, milk fat yield, and energy-corrected milk (ECM), as CSPO caused them to increased to a greater extent in the FGC diet compared with the SFC diet. Furthermore, a tendency for an interaction between CSPO and corn grain-processing method was observed for body weight change, because CSPO increased body weight loss in the FGC diet but not in the SFC diet. The CSPO increased milk yield, milk fat yield, 3.5% fat-corrected milk, ECM, and cumulative milk yield compared with not supplemented. Also, CSPO increased energy intake, milk energy output, and energy partitioning toward milk, whereas reduced energy was allocated to body reserves. The SFC increased milk yield, ECM, milk protein yield, milk casein yield, and cumulative milk yield, and decreased milk urea N compared with FGC. The SFC compared with FGC also increased body condition score and body weight change, and increased energy partitioning toward body reserves. During the carryover period, an interaction between CSPO and corn grain-processing method was observed for milk yield, which occurred because CSPO maintained higher milk yield in the FGC diet but not in the SFC diet. Therefore, in the carryover period, the additive effect between SFC and CSPO that occurred in the treatment period was not maintained throughout the carryover period. However, CSPO increased yields of milk fat, protein, casein as well as fat-corrected milk and ECM. In conclusion, corn grain-processing method interacts with CSPO supplementation on production responses and carryover effects of grazing cows. When CSPO was fed in the FGC diet, milk production increased to a greater extent than when fed in the SFC diet, but also caused greater mobilization of reserves at early lactation. This suggests an interaction between fat supplementation and corn grain-processing method on energy partitioning of dairy cows. Also, both supplementation with CSPO and SFC were effective strategies to increase energy intake and yields of milk and milk solids. The carryover effect on milk production was greater for CSPO supplementation than corn grain-processing method, whereas feeding SFC diets had lower mobilization of reserves and less body weight and body condition score variation throughout lactation.     

Novel,Printable Energetic Polymers

Novel, simple‐to‐make energetic mono‐ and bisvinylimidazolium perchlorate monomers are prepared and characterized. These energetic monomers offer the possibility to 3D print energetic polymers that may allow decreasing the content of the energetic filler in energetic devices without compromising their energetic properties. The new printable materials are suited for photocuring‐based additive manufacturing (AM), techniques, offering not only a large degree of control over the mechanical and energetic properties of the resulting solids, but also the production of complex geometries at high resolution.     

Improvement of mead fermentation by honey‐must supplementation

Through honey's fermentation, diverse beverages can be obtained, among which is mead, an alcoholic drink with 8 to 18% of ethanol (v/v). Since honey is a matrix with a low nutrient concentration and other unfavourable growth conditions, several problems are usually encountered, namely delayed or arrested fermentations, unsatisfactory quality parameters and lack of uniformity of the final product, as well as unpleasant sensory properties. In this context, the aim of this work was to optimize mead production through honey‐must supplementation with (a) salts, (b) vitamins or (c) salts + vitamins. The effects of the honey‐must formulation on the fermentation kinetics, growth profile and physicochemical characteristics of final meads were evaluated. The results showed minor differences in the fermentation profile and time between fermentations with the different formulations. The growth profile was influenced more by the yeast strain than by the supplements added to the honey‐must. In general, the honey‐must composition did not influence meads’ final characteristics, except regarding the SO₂ concentration of the meads produced using the strain QA23. In summary, the addition of salts and/or vitamins to honey‐must had no positive effects on the fermentation, growth profile or characteristics of the final products. Copyright © 2015 The Institute of Brewing & Distilling     

Estimation of the Ballistic Effectiveness of3,4-and3,5-Dinitro-1-(trinitromethyl)-1H-Pyrazoles as Oxidizers for Composite Solid Propellants

The experimental values of the enthalpy of formation of two isomeric 3,4-and 3,5-dinitro-1-(trinitromethyl)-1H-pyrazoles have been obtained(261.5±5.0and 246.4±6.7kJ/mol for crystalline 3,4-and 3,5-dinitro-1-(trinitromethyl)-1H-pyrazoles,respectively).The ballistic effectiveness of these potential oxidizers in composite solid propellants was studied.It is shown that these two oxidizers may be successfully applied in metal-free compositions or with a small content of metal.For the bottom stage 3,4-dinitro-1-(trinitromethyl)-1H-pyrazole is a bit better than 3,5-dinitro-1-(trinitromethyl)-1H-pyrazole,for the upper stage the both oxidizers show the equal ballistic parameters.These oxidizers allow to create metal-free solid composite propellants with the binder percentage not lower than 19%(volume fraction),with I3spequal to 256.5-257.0sat density equal to 1.72-1.74g/cm~3.     

Comprehensive recovery of the components of ferritungstite base on reductive roasting with mixed sodium salts,water leaching and magnetic separation

Ferritungstite ores have great commercial value because of the huge reserve and high content of W, Mo and Fe. But their economic recovery has long been a challenge due to its complex mineralogy and heterogeneous. The current study investigated how reductive roasting of ferritungstite ores with mixed sodium salts affected the phase evolution of W, Mo and Fe through Micro-area XRD and Powder XRD, with the goal of comprehensive transformation of ferritungstite. Reductive roasting with mixed sodium salts at 800 °C transformed ferritungstite to Na₂WO₄ and magnetite (Fe₃O₄), which were easily recovered by water leaching and magnetic separation. Furthermore, a lot of pores and gaps rather than sintering or agglomeration was observed in the ore particles after roasting by SEM-EDS, which was beneficial for the water leaching of W and Mo. As a result, 96.40% of W and 96.64% of Mo were extracted after water leaching, while an iron concentrate with an Fe content of 55.65% and recovery of 83.30% was obtained after magnetic separation. These results suggested such process would be applicable to the comprehensive recovery of valuable metals from ferritungstite ores, as well as similar tungsten ores and scraps.     

Estimation of electrolytic hydrogen production potential in Venezuela from renewable energies

An initial estimation of the potential for hydrogen (H₂) production in Venezuela is made, obtained by water electrolysis using electricity from renewable sources, taking advantage of the great potential of the country for solar, wind and mini hydro energies. For the first two, its potential maps is obtained from insolation and wind speed maps, respectively, prepared from satellite data, and for mini-hydro, the potential is obtained from documentary information. To calculate the amount of H₂ to produce is used the Higher Heating Value, considering the electrolytic system overall efficiency of 75%, including power requirements of the electrolyzer, auxiliary equipment, and system losses. In addition, in the calculation of usable renewable potential are excluded land areas under special administration, marine, lake and urban areas, and other limitations are considered concerning energy conversion efficiencies and useful areas available for the location of the different renewable technologies.     

Al基纳米复合含能材料的自组装

从Al基纳米复合含能材料的能量方面着手分析比较了各种制备方法的优劣,凸显出了自组装法制备Al基纳米复合含能材料的优势。自组装制备方法能够有效控制Al基纳米复合含能材料中粒子的排布,增加粒子各自的分散性和组分粒子之间的接触,缩短了粒子之间的传质和传热距离,提高了Al基纳米复合含能材料的燃烧速率、反应活性和能量利用率。将目前报道的Al基纳米复合含能材料的自组装制备方法分为两类(直接组装法和间接组装法)进行论述总结,最后提出了自组装法在含能材料制备中的发展方向。附参考文献41篇。