Crack damage evolution in coal at elevated temperatures

This work studies the behaviour of coal samples at various thermal environments from sub-zero temperatures of -100 to 300 °C by monitoring their fracture speed, ultimate strength, and crack damage evolution mode. High-speed recordings captured at 140,000 frames per second identified three different fracture evolution modes as a function of the applied ambient temperature. As the temperature increases, the fracture behaviour was observed to be through intact rock bridges resulting in reduced crack speeds and smaller fragments. Interestingly, at sub-zero temperatures, a different failure pattern was observed through the formation of a single fracture plane resulting in larger fragments with sharper edges

Modeling Water Quality Parameters Using Data-driven Methods

Introduction: Surface water bodies are the most easily available water resources. Increase use and waste water withdrawal of surface water causes drastic changes in surface water quality. Water quality, importance as the most vulnerable and important water supply resources is absolutely clear. Unfortunately, in the recent years because of city population increase, economical improvement, and industrial product increase, entry of pollutants to water bodies has been increased. According to that water quality parameters express physical, chemical, and biological water features. So the importance of water quality monitoring is necessary more than before. Each of various uses of water, such as agriculture, drinking, industry, and aquaculture needs the water with a special quality. In the other hand, the exact estimation of concentration of water quality parameter is significant. Material and Methods: In this research, first two input variable models as selection methods (namely, correlation coefficient and principal component analysis) were applied to select the model inputs. Data processing is consisting of three steps, (1) data considering, (2) identification of input data which have efficient on output data, and (3) selecting the training and testing data. Genetic Algorithm-Least Square Support Vector Regression (GA-LSSVR) algorithm were developed to model the water quality parameters. In the LSSVR method is assumed that the relationship between input and output variables is nonlinear, but by using a nonlinear mapping relation can create a space which is named feature space in which relationship between input and output variables is defined linear. The developed algorithm is able to gain maximize the accuracy of the LSSVR method with auto LSSVR parameters. Genetic algorithm (GA) is one of evolutionary algorithm which automatically can find the optimum coefficient of Least Square Support Vector Regression (LSSVR). The GA-LSSVR algorithm was employed to model water quality parameters such as Na+, K+, Mg2+, So42-, Cl-, pH, Electric conductivity (EC) and total dissolved solids (TDS) in the Sefidrood River. For comparison the selected input variable methods coefficient of determination (R2), root mean square error (RMSE), and Nash-Sutcliff (NS) are applied. Results and Discussion: According to Table 5, the results of the GA-LSSVR algorithm by using correlation coefficient and PCA methods approximately show similar results. About pH, EC, and TDS quality parameters, the results of PCA method have, the more accuracy, but the difference of RMSE between the PCA method and correlation coefficient method is not significant. The PCA method cause improvement in NS values to 22 and 0.1 percentages in pH and TDS water quality parameters to the correlation coefficient method, respectively,and NS criteria value for EC water quality parameter did not change in both methods. As a result, according to positive values of NS criteria in both PCA and correlation methods, it is clear that GA-LSSVR has a high ability for modeling of water quality parameters. Because of summation of NS criteria for PCA method is 5.53 and for correlation coefficient is 5.62, we can say that the correlation coefficient method has more applicable as a data processing method, but both methods have a high ability. Orouji et all. (18) used assumed models to model Na+, K+, Mg2+, So42- , Cl- , pH, EC, and TDS by Genetic programming (GP) method. The RMSE criteria of the better models for testing data are 2.1, 0.02, 0.85, 0.93, 2.18, 0.33, 404.15, and 246.15, respectively. For comparison the orouji et al. (18) and table (5), the Results show using the correlation coefficient method as a data processing method can improve the results to 5.5 times. The results indicate the superiority of developingalgorithm increases the modeling accuracy. It is worth mentioning that according to NS criteria both selected inputs variable methods (correlation coefficient and PCA) are capable to model the water quality parameters. Also the result shows that using correlation coefficient method lead to more accurate results than PCA. Conclusion: In this study, GA algorithm as one of the most applicable optimization algorithms in the different sciences was used to optimize the LSSVR coefficients and Then GA-LSSVR was developed to model the water quality parameters. To comparison data processing methods (correlation coefficient and PCA methods), the input variables of both methods were determined and GA-LSSVR was performed for each of the input variables. To compare the results of the PCA and correlation coefficient methods, some statistics were used. It is worth mentioning that according to NS criteria both input selection methods are capable to model water quality parameters. Also the results show that using correlation coefficient method lead to more accurate results than PCA

Drying lakes : A review on the applied restoration strategies and health conditions in contiguous areas

Decrease of saline lakes, which comprise 44% of all available lake water, is a major concern. It additionally accelerates the desertification process of the region. Thus, various countries have taken different actions in protecting their lake water levels. The aim of this paper is to assess different strategies directed to tackle the decreased lake water levels in Lake Urmia and the Aral Sea, which split into the North Aral Sea and South Aral Sea. These are among the world's largest and fastest drying saline lakes observed in the past 50 years and have both reduced to 10% of their original size. The paper presents a thorough review of academic reports, official documents, and databases. Although the dry-up of a lake is a natural process, it has been sped up by human interventions in the hydrological cycle. Dust storms (strong winds) cause problems in the surroundings. In the case of the Aral Sea, they transmit the pollutants from the dry lake bed causing severe health issues. Various strategies were implemented to manage the socio-economic conditions caused due to the drying of lakes. The strategy implemented for the North Aral Sea was to restore the lake by reducing the water withdrawals from the Syr Darya river, which lead to increased water inflow to the sea. The suggested strategy for Lake Urmia was to restore the lake by water transfer activities from various water sources. These projects have not yet been realized. The strategy implemented for the South Aral Sea was to use a dry lake bed to diversify the economy by oil and mineral extraction along with developing a tourist industry based on the considerable interest to come and observe an ecological disaster of such monumental proportions. These findings show that there is no common best solution for this type of problem. The best fit depends on the local context and it is strongly path-dependent

Evaluation of an Innovative Zn Source on Feed Efficiency, Growth Performance, Skin and Bone Quality of Broilers Suffering Heat Stress

One thousand two hundred male broilers were used to evaluate the effect of different dosages of HiZox® on feed efficiency, growth performance and bone quality of broilers suffering from heat stress. A completely randomized design was used, with four treatments and ten replicates. Basal corn–soybean meal diets supplemented with 75, 100 and 125 mg/kg zinc from HiZox and 100 mg/kg zinc from regular ZnO were used to make four treatments. Heat stress was induced after the third week by keeping house temperature between 28–34 °C, from 1 pm until 5 pm. The body weights of the birds that received the diet supplemented with HiZox or ZnO showed no significant difference at 7 and 14 days. Body weight of heat stressed birds fed diets containing different levels of HiZox or ZnO were not different at 28 and 42 days of age. In comparison to the Ross 308 management guide, induced heat stress diminished body weight and feed intake by approximately 17 and 21%, respectively. At 28 days, chickens who received 125 mg/kg Zn from Hizox had better feed efficiency (p p p p p p p p < 0.03). Solubility of Zn in the gizzard of chickens who received HiZox was higher (about 30%) than broilers fed regular ZnO. In conclusion, Zn from HiZox was more efficient in decreasing heat stress mortality, increasing skin resistance and bone breaking strength compared to a regular ZnO source

An experimental study of the thermal performance of the square and rhombic solar collectors

Solar collectors are the key part of solar water heating systems. The most widely produced solar collectors are flat plate solar collectors. In the present study, two types of flat plate collectors, namely square and rhombic collectors are experi¬mentally tested and compared and the thermal performance of both collectors is investigated. The results show both collectors have the same performance around noon (≈61%), but the rhombic collector has better performance in the morning and afternoon. The values for rhombic and square collectors are approximately 56.2% and 53.5% in the morning and 56.1% and 54% in the afternoon, respectively. The effect of flow rate is also studied. The thermal efficiency of rhombic and square flat plate collectors increases in proportion to the flow rate. The results indicated the rhombic collector had better performance in comparison with the square collector with respect to the mass-flow rate

What roles do architectural design and on-site water servicing technologies play in the water performance of residential infill?

More than half of new urban residential developments are planned as infill in Australia's major cities. This provides an unprecedented opportunity to use innovative design and technology to address urban water challenges such as flooding, reduced water security and related infrastructure and urban heat island issues. However, infill can have positive or negative water impacts, depending on architectural design and on-site water servicing technologies implemented. In this study we asked, “What influence does residential infill development have on the local urban water cycle?” and “What roles do architectural design and technologies play?” To answer these questions, a set of 196 design-technology configurations were developed by combining 28 architectural designs and 7 on-site water-servicing technology options. The configurations represent three cases: (i) existing (EX) or before infill, (ii) business-as-usual development (BAU), and (iii) alternative development (ALT). Using the Site-scale Urban Water Mass Balance Assessment (SUWMBA) model and a set of water performance indicators, the impact of configurations on the urban water cycle was quantified. The results showed BAU, on average, increases population density, stormwater discharge, and imported water by 98%, 44% and 85%, and decreases evapotranspiration and infiltration by 53% and 34%, compared to the EX conditions. More population density (141%) with lower impacts on the urban water cycle (21% and 64% increase for stormwater discharge and imported water, and 29% and 17% reduction in evapotranspiration and infiltration) can be achieved by appropriate integration of ALT designs and technologies. Architectural design has a greater influence on urban water flows than the implementation of on-site water servicing technologies. The results have a great implication for sustainable urban water management for managing the risks associated with pluvial flooding, water insecurity, and urban heat. It also highlights the underutilised role of architects and urban planners to address urban water issues.</p