Energetic study of residual forest biomass using calorimetry and thermal analysis

Summary The European policy on energy focus on the search for alternative and renewable sources of energy where forest biomass plays a significant role. In this article, calorific values of different kinds of forest residues (leaves, thin branches, barks, etc.) are reported. These values were measured by combustion bomb calorimetry with the objective of understanding, through different risk indices, the behaviour of forest waste in the case of wildfires, and also to study the use of forest residues as raw materials to be used as energy sources. The study was complemented with determination of elemental analysis, flammability using a standard epiradiator, thermodegradation analysis, and different mechanical tests trying to get relationships between thermal behaviour and some physical properties. The study was carried out on Eucalyptus globulus Labill and Pinus pinaster Aiton, because these forest formations have both high economical and ecological interest in Galicia (NW Spain).     

Structural,magnetic, and morphological study of cosputtered FeAl thin film grown in nonreactive environment

Fe-Al alloying is a matter of interest because of its technological importance and many applications. Different growth conditions may lead to different results, ie, formation of various phases. These phases may be magnetic or nonmagnetic in nature. Cosputtering of Fe and Al with magnetron-sputtering setup provides us with a good option of alloying and to study the various phase formations. As, yet now researchers studied the alloying through cosputtering process only in oxygen environment, so a study in nonreactive environment was inevitable and interesting. Therefore, the authors went for Fe-Al thin-film synthesis using the magnetron sputtering in argon environment. Hence, this paper discusses the Fe and Al alloy formation in argon environment and annealed the samples at different temperatures for different time durations so as to allow various phase formations. The samples were characterized with grazing incidence X-ray diffraction (GIXRD), grazing incidence X-ray reflectivity (GIXRR), magneto-optical Kerr effect (MOKE), and atomic force microscopy (AFM) techniques so as to study structural, morphological, and magnetic properties. The results confirm that cosputtering provides better chances of alloying and also supports formation of various stable phases in comparison with other available techniques.     

Recalibration of U-doped standard glasses through uranium thin film for neutron-fluence measurements

This work presents a recalibration of U-doped standard glasses using natural uranium thin films to be used as most dedicated neutron monitor for fission-track dating. The recalibrated U-doped glasses were used to determine fission-track ages in apatite samples from Brazilian alkaline formations (Alto Paranaíba) and standard Durango apatite. Samples were irradiated in two nuclear reactors with different characteristics and the results were compared. For well-thermalized neutron facility, metal activation monitor was also used. The ages of Alto Paranaíba arch and Durango apatite agree with those determined by other radiometric dating methods and metal activation monitors. These results suggest that the presented recalibration is suitable to be used routinely for fission-track dating studies even in a non-well thermalized neutron facility.     

A random forest of combined features in the classification of cut tobacco based on gas chromatography fingerprinting

We applied the random forest method to discriminate among different kinds of cut tobacco. To overcome the influence of the descending resolution caused by column pollution and the subsequent deterioration of column efficacy at different testing times, we constructed combined peaks by summing the peaks over a specific elution time interval Δt. On constructing tree classifiers, both the original peaks and the combined peaks were considered. A data set of 75 samples from three grades of the same tobacco brand was used to evaluate our method. Two parameters of the random forest were optimized using out-of-bag error, and the relationship between Δt and classification rate was investigated. Experiments show that partial least squares discriminant analysis was not suitable because of the overfitting, and the random forest with the combined features performed more accurately than Naïve Bayes, support vector machines, bootstrap aggregating and the random forest using only its original features.     

Energetic characterization of forest biomass by calorimetry and thermal analysis

The rational and sustainable exploitation of natural resources is one the priority objectives of our consumer society as an unavoidable strategy for survival. In previous articles, research group TERBIPROMAT has established the bases for the elaboration of energy maps of forest biomass. With those data, it is possible to classify the species in terms of their energy content and of their possible application as biofuels following European Norm CEN/TS 14961/2005 on solid biofuels. Main forest species used in this study were Populus and Paulownia. These species have a fast growth and produce big amounts of energetic biomass. To complete this study a comparison with autochthonous forest species, Eucalyptus and Pinus, was made. In this study, a thermogravimetric analysis is employed to qualitative study the resistance to thermal degradation of different forest species. These studies complete those made through static bomb calorimetry, elemental analysis, and different mechanical tests trying to get relationships between thermal behaviour and some physical properties.     

Exploring metabolic syndrome serum profiling based on gas chromatography mass spectrometry and random forest models

Metabolic syndrome (MetS) is a constellation of the most dangerous heart attack risk factors: diabetes and raised fasting plasma glucose, abdominal obesity, high cholesterol and high blood pressure. Analysis and representation of the variances of metabolic profiles is urgently needed for early diagnosis and treatment of MetS. In current study, we proposed a metabolomics approach for analyzing MetS based on GC–MS profiling and random forest models. The serum samples from healthy controls and MetS patients were characterized by GC–MS. Then, random forest (RF) models were used to visually discriminate the serum changes in MetS based on these GC–MS profiles. Simultaneously, some informative metabolites or potential biomarkers were successfully discovered by means of variable importance ranking in random forest models. The metabolites such as 2-hydroxybutyric acid, inositol and d-glucose, were defined as potential biomarkers to diagnose the MetS. These results obtained by proposed method showed that the combining GC–MS profiling with random forest models was a useful approach to analyze metabolites variances and further screen the potential biomarkers for MetS diagnosis.     

Studies of biodegradability of certain oils in forest soil as determined by the respirometric BOD OxiTop method

The suitability of the respirometric BOD OxiTop method for biodegradation studies of different oils in soil was assessed. Different forestry chain oils and wood-preservative oils were used as model substances. Experiments were carried out on different types of Finnish forest soils. The results of these experiments are in good agreement with our earlier results of oil-biodegradation experiments in water. The BOD OxiTop method proved to be a highly suitable analysis method for biodegradation studies of oils in soil.     

Radionuclide fractionation in a forest soil profile

Two alternative approaches, a sequential extraction scheme and the calculation of the variation of the distribution coefficient of radiocaesum in different K–Ca–NH₄ scenarios, were used to study the behaviour and fractionation of this radionuclide in a forest soil profile. The first approach was applied to samples originating from an experiment in which the original L (litter) layer was replaced by an L layer contaminated with a radioactive aerosol, allowing a downward migration of radiocaesium. The samples belonged to different stages after the contamination. The second approach was applied to samples contaminated with soluble radiocaseium. The results indicate that radiocaesium behaviour is quite similar in the Hand A layers, and that the mineral matter seems to govern the behaviour of radiocaesium in case of direct condensed deposition or when radiocaesium is released from structural components of the organic matter phase.     

中子活化分析在鄂尔多斯地区元素分析中的应用

利用中子活化对鄂尔多斯盆地油气田上方的地质样品进行了某些元素的检测,通过实验分析,得到了该地区岩石中某些元素的含量,并对该地区的放射性元素作出了评价,绘制了样品的稀土配分模式图和评价了当地的金属矿产资源情况.结果表明,在油气田的上方,放射性元素铀呈现出负异常;钍和钾无明显异常;岩石中的其它元素和中国大陆地壳元素丰度基本...     

Supramolecular structure of polylactides: Influence of the crystallization parameters on the structure of film samples

The supramolecular formations and structure of the surface of polylactide films were studied. Atomic force and optical microscopy techniques were used to examine the spherulite growth processes and the influence of the sample preparation conditions on the surface parameters of polylactide films. Isothermal crystallization runs produced a number of samples differing in the structure of the supramolecular formations and in the surface roughness characteristics.     

Studies on the effect of milling on reduction of niobium pentaoxide with aluminium

The effect of milling on the aluminothermic reduction of niobium pentaoxide was investigated. Charges of Nb₂O₅ and Al (containing 5 % excess Al) were milled for different time (2, 5 and 10 h). XRD profile of milled samples indicated no phase formations during milling; only peak broadening were seen. Milled and unmilled charges were heated in a thermal analyser up to 1,400 °C. Products of milled charges showed formation of Nb, NbO and Al₂O₃; whereas unmilled hand mixed charges showed formations of Nb₃Al along with Nb and Al₂O₃. The tendency of milled charges towards Nb formations without the presence of aluminides was explained from the increase in surface area of charges caused by particle reduction.     

Mineralogical effect correction in wavelength dispersive X-ray florescence analysis of pressed powder pellets

Two methods are utilized to correct the influence of the mineralogical effect on the calibration of elements in geological samples when the pressed powder pellet method is used in wavelength dispersive X-ray fluorescence analysis. The first method involves checking of the 2θ angle for the analyzed element in each sample to correct peak shift and the second method involves replacing the peak intensity with the peak area of the analytical line, so to correct for any shape distortion of the peak. The results were compared with those obtained from the normal method. Major elements in 27 Chinese Certified Reference Materials (CRMs) of rocks, soils and sediments were calibrated with a linear regression curve without theoretical or empirical coefficients. In view of the K values, the calibrations of all 8 elements were improved by the first method and those of 6 elements were improved by the second method. Sulfur calibrations with 4 iron ore CRMs were improved with the use of both methods. The methods have been successfully applied for the analysis of the major elements in limestone ores from different resources of a cement factory.     

Study of the influence of different forest species on the microbial activity in soils

Microcalorimetry was used to study the seasonal evolution over one year of the microbial activity in a humic-eutrophic Cambisol soil as a function of its forest cover. The study was carried out on three soils with identical origin but covered with different forest species: pine, eucalyptus, and a typical Atlantic-humid riverside forest. Some other physical, chemical and biological properties and environmental parameters, mainly humidity and environmental temperature, were considered to analyze their influence on soil microbial activity. The study was performed using a microcalorimeter Thermal Analysis Monitor 2277 in which the experiments were carried out with 1 g soil samples treated with 1.25 mg glucose g^–1 soil. From the measured results it follows that pine forest soil is the least productive of the three, as it generates an average heat of 2.7 vs. 5.9 J g^–1 generated by the eucalyptus forest soil and 3.1 J g^–1 generated by the riverside forest soil. These results are dependent on the remaining physical, chemical and biological features analysed and because of this, pine forest soil, with a pH value 3.3 in spring, shows a small capacity to maintain a stable microbial population which is the lowest of the three (0.079·10⁸ to 0.46·10⁸ microorganisms g^–1 soil) while riverside soil microbial population is in the range from 7.9·10⁸ to 17·10⁸ microorganisms g^–1 soil.     

气相色谱-稳定同位素质谱法测定溶解无机碳碳同位素

选用NaHCO3配制了浓度分别为0.24、1.19、2.38和4.76 mmol/L的溶解无机碳(D IC)溶液,经过1h、4h、8h和24h不同平衡时间,建立了一种分析D IC碳同位素的方法。不同浓度的D IC样品与其母质NaHCO3的1δ3C值之间的差值仅为(0.2~0.5)‰。通过对照组的实验结果和对空气CO2的碳同位素测试与研究,证明此方法可有效避免实验过程中大气等物质对样品的污染,确保实验结果的准确性。     

Variation of tritium concentration in the course of the degradation of fresh pine needles on a forest floor

Variation of tritium concentration was examined for 100 days in the course of degradation of fresh pine needles, which were left on a pine forest floor. No difference was observed on free water tritium (FWT) and organically bound tritium (OBT) concentrations of sterilized samples by gamma-ray irradiation or fumigation and control samples, attributable to incomplete sterilization. The OBT concentrations did not increase within the experimental period as the level of humus collected from the forest floor. The results suggest that a longer degradation time, more than 100 days, is necessary to elevate OBT up to the level, which is observed in the general environment.     

Characterization of the distribution of the sintering activator boron in powder metallurgical steels with SIMS

Powder metallurgy is a well-established method for manufacturing ferrous precision parts. A very important step is sintering, which can be strongly enhanced by the formation of a liquid phase during the sintering process. Boron activates this process by forming such a liquid phase at about 1200 °C. In this work, the sintering of Fe–B was performed under the protective atmospheres of hydrogen, argon or nitrogen. Using different grain sizes of the added ferroboron leads to different formations of pores and to the formation of secondary pores. The effect of boron was investigated by means of Secondary Ion Mass Spectrometry (SIMS) supported by Scanning Electron Microscopy (SEM) and Light Microscopy (LM). To verify the influence of the process parameters on the mechanical properties, the microstructure (pore shape) was examined and impact energy measurements were performed.The concentrations of B in different samples were varied from 0.03–0.6 weight percent (wt%). Higher boron concentrations are detectable by EPMA, whereas the distributions of boron in the samples with interesting overall concentration in the low wt% range are only detectable by means of SIMS.This work shows that the distribution of boron strongly depends on its concentration and the sintering atmosphere used. At low concentration (up to 0.1 wt%) there are boride precipitations; at higher concentration there is a eutectic iron–boron grain boundary network. There is a decrease of the impact energy observed that correlates with the amount of eutectic phase.     

Effect of Lead Contamination on Soil Microbial Activity Measured by Microcalorimetry

Microcalorimetry was used to investigate the microbial activity in three types of soil (orchard soil, crop soil, forest soil) in Wuhan, China, and to evaluate the influence of different concentrations of lead (Pb²⁺) on soil microbial activity. The experimental results revealed that due to different physical and chemical characteristics of the soils, soil microbial activity in three soil samples were in a descending sequence: orchards soil, crops soil, forest soil. Six levels of Pb viz. 0, 10, 20, 40, 80, 160 μg·g⁻¹ were applied in these soils, and the results showed that an increase of the amount of Pb²⁺ is associated with a decrease in microbial activity in the soils due to the toxic effect of Pb²⁺. In order to gain further insight of the sequential change of microorganisms, determination of colony forming units (CFU) was performed to provide a negative linear correlation between the heat effect and the respective number of microorganisms in the system.     

Conventional and Organic Honeys as a Source of Water- and Ethanol-Soluble Molecules with Nutritional and Antioxidant Characteristics

The benefits of natural honeybee products (e.g., honey, royal jelly, beeswax, propolis, beevenom and pollen) to the immune system are remarkable, and many of them are involved in the induction of antibody production, maturation of immune cells and stimulation of the immune system. The type of plants in the geographical area, climatic conditions and production method have a significantly influence on the nutritional quality of honey. However, this variability can influence consumer liking by the sensory attributes of the product. The aim of this work was to compare the most popular honeys from Poland in terms of nutritional value, organoleptic properties and antioxidant activity. In the study, five varieties of honey (honeydew, forest, buckwheat, linden and dandelion) from conventional and organic production methods were tested. The nutritional characteristics of honey samples included acidity, content of water, sugars, vitamin C, HMF and phenolics (total and flavonoids), while honey color, taste, aroma and consistency were investigated in the organoleptic characteristics. The antioxidant activity was determined in water- and ethanol-soluble honey extracts using DPPH and ORAC tests. The results showed that organoleptic and nutritional characteristics of popular Polish honeys differ significantly in relation to plant source and production method. The significant effect of honey variety on the content of HMF, saccharose and phenolics, as well as acidity and antioxidant capacity were noted. The impact of variety and variety × production method interaction was significant in the case of the content of vitamin C, glucose and fructose. A visible difference of buckwheat and forest honeys from other samples was observed. The highest content of total phenolics with antioxidant activity based on the SET mechanism was found in buckwheat honeys, while forest honeys were richer in flavonoids.     

Effect of pH on lipid oxidation of red onion skin extracts treated with washed tilapia (Oreochromis niloticus) muscle model systems

The aim of the study was to investigate the effect of pH on the lipid oxidation of red onion skin extracts (ROSEs) treated with washed tilapia muscle model systems (WTMS). Minced and buffered washed samples were prepared at pH 6.3 and 6.8. The WTMS were treated with2 different concentrations of red onion skin prior to storage for 5 days. Lipid oxidation was investigated via peroxide values (PVs), thiobarbituric acid reactive substances (TBARS), and the formation of volatile compounds. Fatty acid profiles of the samples were also identified. The ROSEs were able to significantly suppress the PV (~71%) and TBARS (~42%) formation. Hexanal and octanal formations in the WTMS were relatively less in the ROSE-treated samples. The WTMS samples prepared at pH 6.3 were more vulnerable to lipid oxidation than those prepared at pH 6.8. Red onion skin polyphenols may increase the lag phase of lipid oxidation, depending on pH levels, resulting in the shelf life extension of raw fish.     

X射线荧光光谱法结合多元统计学对热敏纸的检验研究

为建立一种快速且无损检验热敏纸的科学有效的方法,利用能量色散型X射线荧光光谱(XRF)对38个不同商家,不同规格的热敏纸样品进行检验,首先根据每个样品所测量得到的元素的不同,将38个样品分成四大类,同时采用SPSS25.0软件中的系统聚类法对38个样品的元素数据进行聚类分析处理,结果分成了12小组,再结合SPSS25.0软件中的判别分析法对上述结果进行验证,实现了基于X射线荧光光谱结合聚类分析建立数学模型用于区分热敏纸种类的目的,该方法简单易行,可以为案件侦破提供线索、指明方向。