Study of the adsorption of reactive blue 50 on zero valent iron

 In this study, removal efficiency of the Reactive blue 50 and adsorption mechanism on the zero valent iron were investigated. Reactive blue 50 which is used to wool and cashmere dyeing were selected due its non-biodegradable and metabolic stability. Zero valent iron particle has been synthesized by chemical method. A systematic characterization of zero valent iron was performed using X-ray diffractometer, scanning electron microscope and infrared spectrometer analysis. The optimal condition of adsorption was determined as initial reactive dye 50 concentration of 150 mg·L-1, zero valent iron mass of 0.2 g and solution pH of 6.0 at room temperature. At optimal condition, organic dye removal in a real wastewater sample from Tsombon Knit LLC was 99.5%.Mongolian Journal of Chemistry 15 (41), 2014, p21-2

Dynamic Key-Value Memory Networks for Knowledge Tracing

Knowledge Tracing (KT) is a task of tracing evolving knowledge state of students with respect to one or more concepts as they engage in a sequence of learning activities. One important purpose of KT is to personalize the practice sequence to help students learn knowledge concepts efficiently. However, existing methods such as Bayesian Knowledge Tracing and Deep Knowledge Tracing either model knowledge state for each predefined concept separately or fail to pinpoint exactly which concepts a student is good at or unfamiliar with. To solve these problems, this work introduces a new model called Dynamic Key-Value Memory Networks (DKVMN) that can exploit the relationships between underlying concepts and directly output a student's mastery level of each concept. Unlike standard memory-augmented neural networks that facilitate a single memory matrix or two static memory matrices, our model has one static matrix called key, which stores the knowledge concepts and the other dynamic matrix called value, which stores and updates the mastery levels of corresponding concepts. Experiments show that our model consistently outperforms the state-of-the-art model in a range of KT datasets. Moreover, the DKVMN model can automatically discover underlying concepts of exercises typically performed by human annotations and depict the changing knowledge state of a student.Comment: To appear in 26th International Conference on World Wide Web (WWW), 201

Deforestation and degradation of forests in the Khustai nuruu mountains of Northern Mongolia

Deforestation and forest degradation in the forest-steppe zone is one of the most pressing issues in the world, involving territory of southern boreal forests in Northern Mongolia. The changes in forest cover between 1999 and 2016 and driving factors to deforestation and forest degradation in the Khustai nuruu mountains of the Northern Mongolia were analyzed. Forest monitoring was carried out in mature and over-mature flat-leaved birch Betula platyphilla Sukacz. forests with an admixture of aspen Populus tremula L. using the combined method of remote sensing and ground based field measurements. We found an accelerated deforestation trend between 2006 and 2009, which amounted to 463 ha (23.2 %) since deforestation in the Khustai nuruu mountains was started. Overall 17-year forest monitoring revealed that a total of 675 ha of forests were completely converted to non-forest area. As urgent measures to mitigate the effects and limit rapid deforestation in study area, it is recommended to improve the sustainable forest management via establishing optimum head of livestock and wild animals, strengthening prevention and control measures against pests, and reforestation on deforested areas using seedling of native tree species taken from forest nurseries in the region

Journey down the Tuin: the hydraulics of an internal draining river from the Khangai Mountains to the Gobi Desert, A

Includes bibliographical references.Presented at the Building resilience of Mongolian rangelands: a trans-disciplinary research conference held on June 9-10, 2015 in Ulaanbaatar, Mongolia.River systems flowing through semi-arid and arid regions provide critical ecosystem services for inhabitants of these areas. In remote and/or difficult to access areas away from population centers, few direct measurements exist to characterize the nature of streamflow in these systems. The Tuin River flows from the rugged high mountain and forest steppe landscape of the Khangai Mountains in central Mongolia to its terminus at Orog Lake in the desert steppe and sand dunes of the northern Gobi Desert. Field measurements taken in June 2012 at numerous locations from river headwaters to mouth were used to characterize streamflow in the main river channel and associated floodplain. From these measurements, channel hydraulic characteristics were estimated and hydrologic properties were assessed using a digital elevation model and other spatial data. These properties include contributing area, slope, hydraulic radius, and channel roughness. During the low flow conditions of the survey, streamflow was decreasing from upstream to downstream. At a point between the Bayankhongor and Bogd gaging stations, streamflow ceased at the surface and reappeared approximately 10 kilometres downstream, exemplifying losing flow conditions and subsurface flow components. The results of this analysis could be scalable to other internally draining river systems, especially for hydrologic modelling