The mass configuration of the buoyancy-driven underwater glider is decomposed and defined. The coupling between the glider body and its internal masses is addressed using the energy law. A glider motion model is established, and the corresponding simulation program is derived using MATLAB. The characteristics of the glider motion are explored using this program. The simulation results show that the basic characteristic of a buoyancy-driven underwater glider is the periodic alternation of downward and upward motions. The glider's spiral motion can be applied to missions in restricted regions. The glider's horizontal velocity, gliding depth and its motion radius in spiral motion can be changed to meet different application purposes by using different glider parameter designs. The simulation also shows that the model is appropriate and the program has strong simulation functions.

<p>Modular hydrological modeling has been around for some time, with early examples such as the Modular Modeling System (MMS) developed in 1996. In 2011,Fenicia et al. introduced the SUPERFLEX modeling framework, refined by Molin et al. (2021) as the Python package SurperflexPy. A framework with an even larger library of processes is the Raven modeling framework introduced by Craig et al. (2020).</p> <p>This work introduces a c++ based R package prioritizing convenience while still offering flexibility for semi-distributed hydrological modelling. The EDCHM framework defines five basic layers: atmosphere, snow pack, land, soil, and ground, with the soil and ground layers able to be further divided into sublayers. Each layer has its own characteristics and state variables such as capacity and water volume. EDCHM defines 12 basic processes, including 10 hydrological and 2 meteorological processes such as evapotranspiration and infiltration. Each process has a single flux output, and it can occur within a single layer or between layers. The input requirements are flexible and depend on the specific method used. A process with a specific method is referred to as a module in EDCHM. EDCHM also includes 34 predefined model structures with fixed connections between processes and layers, ranging from 6 to 15 processes. The key feature of EDCHM is the model builder, which allows users to easily generate the model function just by selecting the process methods, the input data list, and the parameter list with ranges will also be created. This makes it fast and efficient for users to build and calibrate models. EDCHM is implemented in c++ and supports vectorization and parallelization through R-Package Rcpp and furrr. Users can easily build new models with their own ideas or ideas from literature.</p> <p>EDCHM has been tested on 34 east-german catchments, with over 60 models calibrated in lumped form and 6 catchments calibrated with 3 and 5 sub-catchments or more than 50 HRUs. Our results show that EDCHM is highly effective in the application of hydrological modeling, with a key feature being its efficiency.</p> <p> </p> <p>Craig et al. (2020). https://doi.org/10.1016/j.envsoft.2020.104728</p> <p>Fenicia et al. (2011). https://doi.org/10.1029/2010WR010174</p> <p>EDCHM: https://github.com/LuckyKanLei/EDCHM</p>

This paper presents two sequential friction‐spring damper configurations and develops numerical and analytical models, which describe the systems' behavior. The dampers rely on the non‐smooth characteristics of dry friction to quench unwanted oscillations and only dissipate energy once a preset breakaway force of the friction element is exceeded. Since no additional control is required and the dissipation is only present within a given frequency range, this passive amplitude adaptive dissipation contributes to a higher energy efficiency. The dampers' equations of motion are derived and implemented in a numerical model to gain the first insights into the dampers' behavior. These equations of motion are analyzed via averaging methods in combination with a modal decoupling for nonlinear systems, which lead to the dampers' analytical models. The results from both models are compared and show reasonable agreement within the validity range of asymptotic methods. This work proposes two friction based amplitude adaptive dampers and offers a starting point for future experimental validation.

The Measurement-While-Drilling (MWD) system, composed of a tri-axial magnetometer and a tri-axial accelerometer, is widely used in the Horizontal Directional Drilling machine in coal mines. This system can provide attitude information of each measuring point in the borehole, which will eventually allow the trajectory of the borehole to be drawn. The attitude information, however, showed a low-level accuracy, due to the sensor’s imperfection and mounting errors. The accuracy worsened when low-cost sensors were employed, as they had higher random noise. Therefore, an exploration of ways to eliminate the sensor imperfection and mounting tolerance as well as to suppress the noise is needed. In this paper, a feasible calibration approach was designed to address these issues. This new approach combined three foundational calibration algorithms, including the ellipsoidal fitting method, the planar fitting method, and the inner product invariance method. The traditional ellipsoidal fitting method and planar fitting method were optimized by using the recursive least square criterion and omitting the steps of sample data acquisition, respectively. In addition, the noise suppression method was involved in our approach to improve the calibration accuracy. The numerical simulation results showed that the number of sampling points decreased significantly, but the accuracy of the azimuthal angle and the pitch angle fully met the engineering requirements. The experimental results showed that the pitch angle error was reduced by less than 0.5°, and the azimuth error was also reduced by less than 2.5°. It should be noted that this new approach could be implemented without the help of other expensive auxiliary equipment.

<p>Catchments in Saxony differ regarding their physiographic characteristics (topography, geomorphology, geology, land use, soils, etc.) and their climatic boundaries. Both factors influence the flow behavior and the water balance components of catchments. How sensitive the water balance of catchments responds to current and future changes in the climatic boundary conditions is difficult to predict for each catchment and is associated with significant uncertainties. In Saxony, the pronounced drought in groundwater and surface water from 2018 to 2020 led to considerable regional problems in water supply and quality.</p> <p>Schwarze et al. (2017) already investigated trends of the observed discharge and variables derived by hydrograph separation (e.g. baseflow) in a sensitivity study. In this presentation, we show the results of an extension of this analysis with current observation data until 2020. The following research questions are investigated: (i) Are catchments in Saxony already responding to changing climatic conditions? (ii) Which regions show the most significant changes in discharge behavior relative to other water balance components? (iii) What are the factors and drivers of changes in the water balance in Saxonian Catchments?</p> <p>The study is based only on observational data for precipitation, temperature, and discharge in the period of 1961 to 2020 in Saxony. Break point analysis, hydrograph separation, and sensitivity analysis of hydrological signatures are performed for different sets of climate periods to quantify changes and elasticity of the water balance components. As a result, a decreasing trend for the mean flow can be seen for almost all 88 investigated and undisturbed catchments in Saxony. This trend is more pronounced in the mountainous regions than in the lowland of Saxony. Despite the slight increase in the mean annual precipitation, the temperature rise of about one °C from 1991-2020 compared to 1961-1990 in all catchments leads to an increasing evapotranspiration, reduced discharge, and groundwater recharge.</p> <p> </p> <p>References:</p> <p>Schwarze, R., Wagner, M. and Röhm, P. (2017). Adaptation strategies to climate change - Analysis of the sensitivity of water balance variables of Saxon gauge catchments with respect to the increased temperature level from 1988 onwards compared to the reference state of 1961-1987. Ed.: Saxon State Office for Environment, Agriculture and Geology (LfULG), 2017.</p>