Probabilistic simulation of fire endurance of a wooden beam

This paper presents a probabilistic simulation approach to assessment of the fire endurance of a wooden load-bearing beam in a fire. The approach introduces several novel modelling techniques developed by VTT, such as the probabilistic fire simulator which is an interface enabling to run fire simulation models in the Monte Carlo mode and the time-dependent event-tree method which enables to take into account the active fire safety measures such as detectors, first-aid fire fighting, sprinklers and fire brigade intervention. Also the simulation of the response to heat and the mechanical performance of the structure are carried out using the Monte Carlo technique. The charring rate of the wooden beam is calculated by a new model that includes explicitly the principal sources of uncertainties and variabilites. The results show explicitly the effectiveness of different fire safety measures in reducing the risk of structural failure.     

Statistical analysis of agronomical factors and weather conditions influencing deoxynivalenol levels in oats in Scandinavia

The relationship between weather data and agronomical factors and deoxynivalenol (DON) levels in oats was examined with the aim of developing a predictive model. Data were collected from a total of 674 fields during periods of up to 10 years in Finland, Norway and Sweden, and included DON levels in the harvested oats crop, agronomical factors and weather data. The results show that there was a large regional variation in DON levels, with higher levels in one region in Norway compared with other regions in Norway, Finland and Sweden. In this region the median DON level was 1000?ng?g(-1) and the regulatory limit for human consumption (1750?ng?g(-1)) was exceeded in 28% of the samples. In other regions the median DON levels ranged from 75 to 270?ng?g(-1), and DON levels exceeded 1750?ng?g(-1) in 3-8% of the samples. Including more variables than region in a multiple regression model only increased the adjusted coefficient of determination from 0.17 to 0.24, indicating that very little of the variation in DON levels could be explained by weather data or agronomical factors. Thus, it was not possible to predict DON levels based on the variables included in this study. Further studies are needed to solve this problem. Apparently the infection and/or growth of DON producing Fusarium species are promoted in certain regions. One possibility may be to study the species distribution of fungal communities and their changes during the oats cultivation period in more detail.     

Contents of Fusarium toxins in Finnish and imported grains and feeds

The aim of the present study was to investigate the levels of trichothecenes in representative samples of Finnish and imported cereals and feeds from the 1987 and 1988 crops. Trichothecene concentrations were determined in samples as trimethylsilylether derivatives by a gas chromatograph equipped with a mass selective detector (GC-MSD) using selected ion monitoring (SIM) which proved to be a reliable and sufficiently sensitive technique. Representative samples of Finnish and imported oats, wheat, barley, rye, maize gluten, soy granules, rapeseed, turnip rapeseed, fish meal, poultry feed and pig feed were analysed employing 19-nortestosterone as an internal standard. Almost all grain and feed samples contained deoxynivalenol (DON) from 7 to 300 micrograms/kg and smaller amounts (13-120 micrograms/kg) of 3-acetyldeoxynivalenol (3-AcDON). The most toxic trichothecenes, T-2, HT-2 toxins and nivalenol (NIV) and also zeralenone (ZEN) were found at low concentrations in some samples. Six lots of oats containing 1.3-2.6 mg/kg of DON and 0.2-0.6 mg/kg of 3-AcDON were found in the Finnish grain samples. Silo samples of almost all imported grains contained DON but at levels below 50 micrograms/kg. Imported grains contained no other trichothecenes. DON, 3-AcDON and ZEN were found in imported feedstuffs at low concentrations.     

Burning characteristics of selected substances: influence of suppression with water

The influence of suppression with water spray on the burning characteristics and composition of fire effluents of nylon, polypropylene and two industrial chemicals was investigated. The experiments were performed using a controlled‐atmosphere cone calorimeter in which the ventilation conditions could be altered. The water spray was applied with a single horizontally positioned nozzle. In the experiments time to ignition, rate of heat release, sample weight and smoke production as well as the composition of the fire effluents were measured; the chemical analysis techniques employed were Fourier‐transform infrared spectroscopy and gas chromatography/mass spectroscopy. The results give quantified information on the effects that water application may have on the burning and the properties of the exhaust gases. A comparison with results of similar experiments with no water application reveal notable changes, e.g. in the production of the toxic fire effluents. Copyright © 1999 John Wiley & Sons, Ltd.     

Updated survey of Fusarium species and toxins in Finnish cereal grains

The aim of the project was to produce updated information during 2005–14 on the Fusarium species found in Finnish cereal grains, and the toxins produced by them, as the last comprehensive survey study of Fusarium species and their toxins in Finland was carried out at the turn of the 1960s and the 1970s. Another aim was to use the latest molecular and chemical methods to investigate the occurrence and correlation of Fusarium species and their mycotoxins in Finland. The most common Fusarium species found in Finland in the FinMyco project 2005 and 2006 were F. avenaceum, F. culmorum, F. graminearum, F. poae, F. sporotrichioides and F. langsethiae. F. avenaceum was the most dominant species in barley, spring wheat and oat samples. The occurrence of F. culmorum and F. graminearum was high in oats and barley. Infection by Fusarium fungi was the lowest in winter cereal grains. The incidence of Fusarium species in 2005 was much higher than in 2006 due to weather conditions. F. langsethiae has become much more common in Finland since 2001. F. graminearum has also risen in the order of importance. A highly significant correlation was found between Fusarium graminearum DNA and deoxynivalenol (DON) levels in Finnish oats, barley and wheat. When comparing the FinMyco data in 2005–06 with the results of the Finnish safety monitoring programme for 2005–14, spring cereals were noted as being more susceptible to infection by Fusarium fungi and the formation of toxins. The contents of T-2 and HT-2 toxins and the frequency of exceptionally high DON concentrations all increased in Finland during 2005–14. Beauvericin (BEA), enniatins (ENNs) and moniliformin (MON) were also very common contaminants of Finnish grains in 2005–06. Climate change is leading to warmer weather, and this may indicate more changes in Finnish Fusarium mycobiota and toxin contents and profiles in the near future.     

Isolation and purification of egg yolk phospholipids using liquid extraction and pilot-scale supercritical fluid techniques

Egg yolk is an excellent source of phospholipids. Egg yolk powder (EYP) contains about 60% lipids, which consist of, on average, neutral lipids (65%), phospholipids (31%) and cholesterol (4%). The utilization of supercritical fluid techniques is a new way to selectively extract and fractionate non-polar and slightly polar components from foods and food products. In this study, we developed pilot-scale production methods for the isolation of high-purity egg yolk phospholipids. The method involves either liquid ethanol or supercritical fluid extraction (SFE) as isolation method and supercritical antisolvent process as precipitation method. EYP was fractionated to lipid- and protein-rich fractions using liquid ethanol or supercritical fluid as an extraction medium. In both cases, the target fraction was phospholipids dissolved in ethanol. From this solution, phospholipids were precipitated using supercritical carbon dioxide as antisolvent. Depending on the process conditions, 72–99% of the precipitate consisted of phosphatidyl choline and phosphatidyl ethanolamine, which appeared in ratios 6:1–7:1. The highest purity of phospholipids was obtained via precipitation of the isolate obtained using two-step SFE.     

Effect of precursor particle size and morphology on lithiation of Ni0.6Mn0.2Co0.2(OH)2

In this paper, Ni_0.6Mn_0.2Co_0.2(OH)₂ precursors with several different morphologies and particle sizes are mixed with Li₂CO₃ and heat treated for 5, 7.5 and 10 h. The effects of the precursor properties on the degree of lithiation, electrochemical properties and volumetric capacities of lithiated product are compared. Based on the characterization results, a small (3 μm), narrow span precursor can be lithiated in a short period of time (5 h) and has good initial discharge capacity (185 mA h g^??1) and capacity retention (93% for 55 cycles). In contrast, a large wide-span precursor requires over 10 h for full lithiation. A highly porous precursor can be lithiated faster than traditional large wide-span materials, and has low cation mixing and good crystallinity. However, the volumetric energy density of porous material is low after lithiation compared to the other tested materials. Capacity retention after washing correlated with crystallographic properties of the sample.

Graphic abstract

     

创新性淀粉节约方案——通过纤维中的淀粉回收提高纸板生产的可持续性

用于制造再生纸和纸板的纤维原材料中含有大量淀粉。由于微生物的活性,使用回收纤维的纸浆中的过程水通常含有大量淀粉水解酶。这经常导致大多数淀粉在回收纤维进入造纸机之前水解掉,因此潜在地增加了废水中的化学需氧量COD、pH值降低,并且由于碳酸钙溶解使得电导率变高。在本文中,我们提出了一种新颖的提高淀粉再利用及包装纸强度的理念。该理念包括使用特定的淀粉酶抑制剂,防止回收纤维和损纸中的淀粉水解,以及全新的助留系统用以提高淀粉在最终产品中的保留率。淀粉酶抑制剂自身或与杀菌剂组合能够有效防止淀粉水解。这在实验室研究和工厂试验均有所体现。此外,留着率和强度实验表明混凝剂、微聚物和新的高分子聚合物的组合提高了淀粉的留着率和滤水性。