Prediction of in situ rock strength using sonic velocity

Uniaxial Compressive Strength (UCS) and sonic velocity correlations are used widely in the Australian coal mining industry to predict in situ rock strength. These models are cheap, fast and easy to produce, as well as easy to understand and have a number of practical applications in mine planning and design. The major downfall of these models is that there is a large variation in UCS values at high sonic velocities limiting their predictive ability. The aim of this research project is to improve the reliability of UCS/Sonic velocity correlations by reducing the variability in the underlying data. This is performed by identifying and eliminating sources of error affecting the data and looking at the impact of certain factors on the quality of the correlations. Results show that improved models can be obtained by filtering the datasets to remove samples with high length-to-height ratios, conglomerate or pebbly lithologies, and large sonic velocity ranges

Effects of different planting dates on improving yield of Fritillaria imperialis L. and Fritillaria persica L. bulbs damaged by small narcissus fly (Eumerus strigatus Fallen)

Fritillaria imperialis and F. persica were planted during April 2003 and May 2004 growing seasons on the basis of split block design with three replications to investigate the effects of planting dates on various plant parameters and extent of recovery by planting 25% damaged bulbs. The results showed significant effects of planting dates on plant height, number of bulbs per plant and infected bulb ratio. A comparison of the two species showed that F. persica gave more bulblets than F. imperialis. A generalcomparison of the two species also showed that damaged bulbs of F. imperialis produced lesser yield compared to F. persica. Furthermore, both species gave more number of bulblets from early and mid September plantings compared to early and mid October plantings. The most suitable date of planting was determined as September 1st and 15th

A study on wear rates of 100Cr6 steel running against sintered steel surfaces under dry and starved lubrication

This paper investigates the tribological behavior of 100Cr6 steel pin running against sintered steel bearing material used in hermetic compressors. Tests were conducted under dry and starved lubrication sliding conditions in air at room temperature. Although porous structure acts as crack initiation sites thus limiting the wear resistance of sintered iron in dry sliding conditions under high contact stresses, it is believed to be beneficial in lubricated sliding conditions as it absorbs a large amount of lubricant. Wear tests without lubrication show that these pores are completely filled by abrasive particles in the initial stages of the test and no longer maintain their oil absorption capability. Initial results show that oxidation of frictional surfaces by flash temperature in dry conditions reduces weight loss volume by decreasing the coefficient of friction

Effects of sowing date on some agronomic characteristics and alkaloid content of Datura stramonium in semi-arid conditions

Alkaloids of diferent plant, including many Solanaceae species, constitute important natural sources for variety of pharmaceutical products. The amounts of various secondary plant products are strongly dependent on the growing conditions and agronomical applications such as planting date, fertilization, irrigation etc. The aim of this was to study the effects of sowing date on some agronomic characteristics and total alkaloid content of thorn apple (Datura stramonium), investigated in the environmental conditions from Dicle University, Agricultural Faculty, Field Crops Department experimental area, during 2010 and 2011 growing years. In the research, plant height, stem diameter, number of branches per plant, number of capsule per plant, capsule width, capsule length, 1000-seed weight, fresh herb yield, herba yield, seed yield and total alkaloid content were examined. At the end of the study, in the trial of thorn apple with sowing dates, according to two years mean, seed yield, fresh herb yield, dry herb yield and total alkaloid yield were changed between 335 kg ha-1 and 704 kg ha-1, 5933 and 20537 kg ha-1, 1613 kg ha-1 and 4800 kg ha-1, and 0.270% and 0.391%, respectively. The effect of sowing date was found significant on the investigated characteristics, when sowing delayed, agronomic characteristics were also decreased. The highest values related with seed yield, fresh and dry herbage of thorn apple were obtained sowing of 01 Apr. Moreover, thorn apple plant showed morphogenetic variation when compared leaf and seed alkaloid contents

Essential oil and microelement composition of Thymus citriodorus L. and Lippia citriodora H.B.K.

Lemon verbena (Lippia citriodora H.B.K., Verbenaceae family) is indigenous to South America and cultivated as an aromatic plant in various parts of world. Lemon thyme (Thymus citriodorus L.), Lamiaceae family, is a perennial medicinal plant native to southern Europe and is cultivated in the Mediterranean region. These species are cultivated mainly for the lemon-like aroma emitted from their leaves due to the presence of dimethyl-2,6- octadienal, also known as lemonal or citral, which is used in food and perfumery for its citrus effect. The aim of this study was to determine the mineral content and essential oil components of L. citriodora and T. citriodorus plants grown under semi-arid climatic conditions in Turkey. The aerial parts of lemon thyme and lemon verbena plants were extracted using hydrodistillation. The essential oil composition was analyzed by gas chromatography-mass spectrometry (GC-MS) and the microelement contents of the herbs were examined via inductively coupled plasmaoptical emission spectrometry (ICP-OES). The microelement contents were 0.249, 1.630, 16.41, 0.106, and 13.1-36.2 mg kg-1 for cadmium (Cd), copper (Cu), iron (Fe), and manganese (Mn), respectively, in lemon thyme, and 0.275, 4.584, 248.1, 15.71, and 1.803 mg kg-1 for Cd, Cu, Fe, Mn, and zinc (Zn), respectively, in lemon verbena. Fifty compounds were identified in lemon verbena essential oil, including limonene (30.33%), trans-citral (17%), cis-citral (12.77%), caryophyllene oxide (5.71%), and geraniol acetate (4.02%) that together constituted 99.86% of the oil composition. We also identified 22 compounds constituting approximately 85.11% of lemon thyme essential oil, including transgeraniol (30.07%), trans-citral (15.06%), cis-citral (11.71%), cis-geraniol (7.65%), and 3-octanol (6.18%)

Effect of different nitrogen doses on some agricultural characteristics and alkaloid content of Hyoscyamus reticulatus L and Hyoscyamus Niger L.

Alkaloids, nitrogen containing basic substance, have a complex structure. They are one of the most important groups of secondary metabolites, which is synthesized in roots and transported to other organs. Since alkaloids are nitrogenous compounds, the availability of nitrogen is expected to play an important role in the biosynthesis and accumulation of alkaloids in plants. Nitrogen affects yield and quality of medicinal plants, therefore, growers usually apply large amount of nitrogen to obtain high yields. The objective of the present study was to determine yield, yield components and alkaloid content of two henbane species (Hyoscyamus reticulatus L. and Hyoscyamus niger L.), collected from wild flora of South-eastern Anatolia, grown under four nitrogen applications (0, 50, 100 and 200 kg ha-1), in 2010-2011 growing seasons. In the field trial, plant height, stem diameter, number of branches per plant, number of capsule per plant, capsule width, capsule length, number of seed per capsule, 1000 seed weight, seed yield per plant and total alkaloid content were investigated. The results of study showed that nitrogen doses were found important for investigated characters but not important for Hyoscyamus species. Seed yield per plant varied from 8.4 to 11.6 g per plant, their alkaloid contents were found between 0.14% and 0.21%

Modelling of the Occurrence of Hydrogen Sulphide in Coal Seams

Hydrogen Sulphide (H2S) has been encountered within a number of Bowen Basin collieries, Central Queensland, Australia. High concentration occurrence during mining of a longwall panel raises a number of potential problems, which demand greater understanding to allow efficient mining while maintaining safe and healthy environmental conditions. Longwall panels at Mine A and Mine B have recently mined through H2S zones. The high H2S zone mined through at Mine A was wide and covering the whole length of the face comparing to the narrow H2S zone which was cutting the panel at 45° at Mine B. Longwall panels had been sampled for H2S in pre-mining phases with vertical and inseam exploration boreholes and rib sampling of gateroad development headings. During mining face coal samples were collected in an intensive program and tested in a drum tumbler to determine an indicated seam concentration level through contouring that could be used to calculate the concentrations of H2S liberated to the atmosphere. Data was analysed to determine a geostatistical method, which would best represent the indicated seam concentration level from the given data and the block dimension of the data set. This study discusses the different sampling methods used, selection of the most suitable geostatistical method and the impact of grid size on results of data analysis. Some general observations are made correlating indicated seam H2S concentrations from production face sampling with both predictions made from exploration and liberation rates during mining of the longwall panel

Improving the performance of the hardy cross algorithm for large ventilation models

The Hardy Cross algorithm offers a reliable method of solving network systems of fluid flow and has become widely used for solving water and ventilation flow networks. A limitation is that computational iterations and time to solve a network rises rapidly with the size of the model and modern detailed ventilation networks have typically grown to thousands of airways. Non-linear matrix solving methods can offer improved performance, however these are more complex and may be unstable if initial estimates are poor. This paper presents improvements that can be applied to the traditional Hardy Cross algorithm to greatly reduce iterations and solving time for large ventilation models