29 research outputs found
Review of experimental methods to determine spontaneous combustion susceptibility of coal – Indian context
This paper presents a critical review of the different techniques developed to investigate the susceptibility of coal to spontaneous combustion and fire. These methods may be sub-classified into the two following areas: (1) Basic coal characterisation studies (chemical constituents) and their influence on spontaneous combustion susceptibility. (2) Test methods to assess the susceptibility of a coal sample to spontaneous combustion. This is followed by a critical literature review that summarises previous research with special emphasis given to Indian coals
International Society of Sports Nutrition Position Stand: Probiotics.
Position statement: The International Society of Sports Nutrition (ISSN) provides an objective and critical review of the mechanisms and use of probiotic supplementation to optimize the health, performance, and recovery of athletes. Based on the current available literature, the conclusions of the ISSN are as follows: 1)Probiotics are live microorganisms that, when administered in adequate amounts, confer a health benefit on the host (FAO/WHO).2)Probiotic administration has been linked to a multitude of health benefits, with gut and immune health being the most researched applications.3)Despite the existence of shared, core mechanisms for probiotic function, health benefits of probiotics are strain- and dose-dependent.4)Athletes have varying gut microbiota compositions that appear to reflect the activity level of the host in comparison to sedentary people, with the differences linked primarily to the volume of exercise and amount of protein consumption. Whether differences in gut microbiota composition affect probiotic efficacy is unknown.5)The main function of the gut is to digest food and absorb nutrients. In athletic populations, certain probiotics strains can increase absorption of key nutrients such as amino acids from protein, and affect the pharmacology and physiological properties of multiple food components.6)Immune depression in athletes worsens with excessive training load, psychological stress, disturbed sleep, and environmental extremes, all of which can contribute to an increased risk of respiratory tract infections. In certain situations, including exposure to crowds, foreign travel and poor hygiene at home, and training or competition venues, athletes' exposure to pathogens may be elevated leading to increased rates of infections. Approximately 70% of the immune system is located in the gut and probiotic supplementation has been shown to promote a healthy immune response. In an athletic population, specific probiotic strains can reduce the number of episodes, severity and duration of upper respiratory tract infections.7)Intense, prolonged exercise, especially in the heat, has been shown to increase gut permeability which potentially can result in systemic toxemia. Specific probiotic strains can improve the integrity of the gut-barrier function in athletes.8)Administration of selected anti-inflammatory probiotic strains have been linked to improved recovery from muscle-damaging exercise.9)The minimal effective dose and method of administration (potency per serving, single vs. split dose, delivery form) of a specific probiotic strain depends on validation studies for this particular strain. Products that contain probiotics must include the genus, species, and strain of each live microorganism on its label as well as the total estimated quantity of each probiotic strain at the end of the product's shelf life, as measured by colony forming units (CFU) or live cells.10)Preclinical and early human research has shown potential probiotic benefits relevant to an athletic population that include improved body composition and lean body mass, normalizing age-related declines in testosterone levels, reductions in cortisol levels indicating improved responses to a physical or mental stressor, reduction of exercise-induced lactate, and increased neurotransmitter synthesis, cognition and mood. However, these potential benefits require validation in more rigorous human studies and in an athletic population
Low Temperature Oxidation of a High Volatile Bituminous Turkish Coal Effects of Temperature and Particle Size
Low-temperature oxidation of a high volatile bituminous Turkish coal was studied using an isothermal flow reactor technique under different experimental conditions. Coal samples were ground and sieved to three different particle sizes namely -850 μm, -425 μm and -300 μm. The samples were oxidised at 40, 60 and 90°C with an oxygen flow rate of 45 mL/min. CO2 and CO emissions were analysed using an HP 5897 Series II type gas chromatograph. Temperature was found to have a definite effect; as the temperature increased rates of formation of CO2 and CO also increased significantly. Experimental results showed that the rates of formation of CO2 and CO are independent of the particle size of the samples
Relations between coal properties and spontaneous combustion parameters
The results of linear and multiple regression analyses to determine the relationship between spontaneous combustion parameters (derived from time-temperature curves obtained from laboratory tests) and coal parameters (obtained from proximate, ultimate and petrographic analyses) have been explained. The linear regression analyses have shown that ash (A), volatile matter (VM), carbon (C), hydrogen (H), exinite (E), inertinite (I) and mineral matter (MM) are the major factors affecting spontaneous combustion. According to the multiple regression analyses, these major factors are volatile matter, carbon, hydrogen, nitrogen (N), oxygen (O), sulphur (S) and inertinite. As a result of this study, some empirical equations have been derived using statistical models
Determination of the gas content of buyuk seam of ttk armutcuk colliery by direct measurement method [Ttk armutçuk müessesesi büyük damar gaz içeriginin dogrudan ölçme yöntemiyle belirlenmesi]
The goal of this study is to determine the gas content of Buyuk seam at TTK's Armutcuk Colliery by applying one of the direct methods. The direct gas measurement methods used to determine the gas contents of the coal seams were studied and Australian Standard was selected as suitable. In this study, using the cuttings obtained from 12 core drillings done in a virgin section of Buyuk Seam (-540 level) of Armutcuk Colliery of TTK, where a panel development is readily conducted gas content of the samples were determined according to "fast and slow desorption" procedures. The results obtained from the study revealed that gas contents of coal samples are in the range of 8,5-14,7 m3/t, and 9,0-17.4 m3/t by fast and slow desorption method, respectively. Arithmetic averages of the gas contents at this part of the Buyuk seam shows that the gas content can be accepted as 10-12 m3/t. Also, the initial desorption of a sample is accepted first as linear then as logarithmic and only slight differences have been observed between two approaches regarding the total gas contents. The Australian Standard method can easily be used on borehole cuttings in TTK collieries adapting the instrumentation achieved and experience gained in this study
Statistical modeling of the effect of rank, temperature, and particle size on low-temperature oxidation of turkish coals
This paper aims to investigate the differences between the low-temperature oxidation behavior of some Turkish coals having different ranks by statistically analyzing the formation rates of CO2 and CO as well as the ratio of CO/CO2. In order to do this, oxidation experiments were performed on four Turkish coals grouped at -425+212, -212+150, and -150+106m size groups and oxidized at 40, 60, and 90C, respectively. Then, a step-by-step multiple-regression analysis was conducted to assess the effect of rank, temperature, and particle size by determining the variation in the formation rates of CO and CO2 as well as the ratio of CO/CO2 over time for the data set obtained from the experiments. Regression results showed that as the rank increases the formation rates of CO and CO2 it also increases the magnitude, and they decrease faster over time. The effect of temperature was clearly confirmed by the regression results as indicated by the temperature dummy, whereas the effect of particle size at close ranges of size groups was not clearly acquired. Copyright © Taylor & Francis Group, LLC
Low-temperature oxidation of some Turkish coals
Low-temperature oxidation of four different-rank Turkish coals was studied in order to assess the effects of temperature, particle size, coal petrography, and coal rank by monitoring CO 2 and CO formation rates and calculated CO/CO 2 ratios. Coals were classified to -425 + 212, -212 + 150, and -150 + 106 µm size groups and oxidized at 40, 60, and 90 °C. Temperature has a pronounced effect on the formation rates of CO 2 and CO; when the temperature increases, the formation rates of CO 2 and CO also increases. Nevertheless, the formation rates of CO 2 and CO were found to be independent of particle size, particularly at relatively lower temperatures. Petrographic analysis showed that the coal sample having the highest inertinite group macerals was oxidized more easily, thus, yielding more CO 2 and CO. Relatively higher rank coals were oxidized more easily, but oxidation diminishes with time. On the contrary, oxidation progresses with time for lower rank samples especially at relatively higher temperatures. © 2011 Elsevier Ltd. All rights reserved
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Determination of specific criteria about the ignition point temperatures and liability to spontaneous combustion of Zonguldak-Turkish hardcoal seams [zonguldak - Türkiye taşkömürlerinin tutuşma si{dotless}cakli{dotless}klari{dotless} ile ilgili özgün kriterlerin ve kendiliginden yanmaya yatki{dotless}nli{dotless}klari{dotless}ni{dotless}n belirlenmesi]
Boren;DEMiR Export;et al;metso Expect results;Outotec;TMMOB Maden Muhendisleri Odasi23rd International Mining Congress and Exhibition of Turkey, IMCET 2013 -- 16 April 2013 through 19 April 2013 -- Antalya -- 105453Most of coal seams are liable to spontaneous combustion in Zonguldak Hard Coal Basin. For more effective measures against fires in the mines, determination of spontaneous combustion characteristics and liability of coal seams to spontaneous combustion is very important. Therefore, ignition temperatures of hard coals have been determined by TGAMS system and crossing point technique together with the related specific criteria. Also characteristics of combustion are calculated from TGDTG thermograms. Also relationship between ignition temperatures and coal constituents are investigated. Tests are carried on the coal samples taken from Kozlu (Çay, Haci{dotless}memiş, Kurul, Sulu), Üzülmez (Kurul, Piriç, Acun, Taban Aci{dotless}li{dotless}k), Amasra (Kali{dotless}n, Taşli{dotless}, Tavan) and Karadon (Sulu, Haci{dotless}memiş) Collieries of Turkish Hardcoal Enterprises
Carboniferous plant fossils from northern Turkey in the Jongmans Collection, Naturalis, Leiden
The Jongmans Collection in Naturalis, Leiden, the Netherlands, is an internationally important resource of paleobotanical data that includes over 4000 Carboniferous plant fossils from northern Turkey. It was the result of two field excursions by Jongmans in Turkey during 1938 and 1946, and includes specimens collected by him, and specimens donated to him by Turkish, Swiss, and Austrian colleagues. Although not comprehensive, it is the most important source of data for the study of Carboniferous vegetation dynamics and biostratigraphy in the easternmost part of Variscan Euramerica. This in turn is vital for understanding how the progressive collapse of the Euramerican wetland biome started in the Early Moscovian, a vegetation change that coincided with the onset of a marked global climatic warming. © 2017, Pleiades Publishing, Ltd