Investigation of the Anisotropic Structure of Travertine in Terms of Geological and Physico-Mechanical Properties: Sarıhıdır (Avanos-Nevşehir) Travertine Quarry

Travertine is a sedimentary rock with generally layered structure, mainly comprising carbonate. They are used for different purposes in interior and exterior spaces by cutting parallel or perpendicular to the bedding according to use. Travertine may contain several facies linked to variations in conditions during formation. With these features, travertine is one of the rocks with anisotropy most commonly observed. In this study, the anisotropic structure due to facies and layering in travertine was investigated considering geological and engineering properties. The Sarıhıdır travertine quarry face was divided into four different zones with different features. Chemical, mineralogic, physical, index and mechanical properties of the samples taken from these zones were determined. During determination of engineering parameters, samples were prepared parallel and perpendicular to bedding. The source of the travertine is a mixture of limestone, dolomite, evaporite and ultramafic rocks and they have epigean character, though they were affected by the hypogean environment. It appeared there were textural differences between the zones, rather than differences in chemical and mineralogic composition. When travertine was cut parallel to layering, all zones were suitable for decoration and facing. Only T-4 zone samples cut parallel were useable for flooring and load-bearing elements. In terms of compression and abrasion resistance, T-4 zone was better than the other zones. The cut direction of the travertine samples is an important factor for physical and mechanical behavior. Samples cut parallel to layering were observed to provide better results. According to the results, it is recommended to use products from the same travertine zone side-by-side in structures and to consider the cutting direction for long life of the building and to prevent economic losses.

Strengthening Of Soft Soil Using Caboxymethyl Cellelouse Biopolymer

The application of appropriate chemicals is a widely used strategy for soil stabilization. The drive of this study is to determine the possibility of using the biopolymer carboxymethyl cellulose as an environmentally acceptable soil stabilizer. In this work, Atterberge limits tests, specific gravity, compaction, and consolidation tests were used to determine the engineering parameters of soils treated with varying amounts of biopolymer. Additionally, changes in the morphological properties of the soft soils were evaluated using scanning electron microscopy (SEM). It was estimated that as the soil’s biopolymer content increases, the specific gravity drops down, though the optimum water content (OMC) is extended. The outcomes showed diverse effects on Atterberg’s limits by cumulative the liquid limit(LL) and plasticity index (PI) though decreasing the plastic limit as the bio-polymer content increases. By the addition in polymer gratified, the combination boundaries (Solidity index Cc and recompression index Cr) decline.

A sensitivity analysis of a single extraction well from deep geothermal aquifers in the Cheshire Basin, UK

Deep hot sedimentary aquifers (HSAs) are targeted for geothermal exploitation in the Cheshire Basin, UK. In this study, a single extraction well targeting the Collyhurst Sandstone Formation was modelled on MATLAB coupling heat and fluid flux. The Collyhurst Sandstone Formation in the Crewe area of the Cheshire Basin is expected to be found at a depth of 2.8 to 3.5 km, and was chosen as an area for geothermal exploration due to the high demand for energy.Model results suggest that low-enthalpy, deep geothermal systems with thick HSAs are affected by both geological and engineering parameters. The results of this study highlight that the thermal gradient, hydraulic conductivity, production rate, length and position of the well screen are the key parameters capable of affecting the success and viability of any single well scheme. Poor planning during exploration and development can hinder the productivity of any single well scheme and these parameters must be considered to fully understand the risk. Engineering parameters, such as the length of the well screen, can be used during well planning to mitigate geological risks in the aquifer, whilst the results presented can also be used as a guide for energy potential under varying conditions.

The dependence of confinement on the isotope mass in the core and the edge of AUG and JET-ILW H-mode plasmas

Experiments in ASDEX Upgrade (AUG) and JET with the ITER-like wall (JET-ILW) are performed to separate the pedestal and core contributions to confinement in H-modes with different main ion masses. A strong isotope mass dependence in the pedestal is found which is enhanced at high gas puffing. This is because the ELM type changes when going from D to H for matched engineering parameters, which is likely due to differences in the inter ELM transport with isotope mass. The pedestal can be matched in H and D plasmas by varying only the triangularity and keeping the engineering parameters relevant for core transport the same. With matched pedestals ASTRA/TGLF (Sat1geo) core transport simulations predict the experimental profiles equally well for H and D. These core transport simulations show a negligible negative mass dependence and no gyro-Bohm scaling is observed. However, to match the experimental observations at medium β it is required to take the fast-ion dilution and rotation into account. This is not enough for high β plasmas where for the first time a profile match between H and D plasmas was achieved experimentally. Under these conditions quasilinear modelling with TGLF over predicts the transport in the core of H and D plasmas alike.

Strength and Compressibility of Ammonia-Soda Residue from the Solvay Sodium Plant

This work presents the discussion of the results for an experimental study conducted to characterise the mechanical behaviour of ammonia-soda residue (ASR). The calcareous sludge is an alkaline waste formed during the production of soda ash and deposited at the area of the former Solvay Sodium Plant factory in Krakow, Poland. Isotropically consolidation drained (CID) triaxial tests and constant rate of strain (CRS) consolidation tests include the full saturation with water, completion of the consolidation, and the loading/strain rate choice. For this purpose, ASR undisturbed samples were collected from the ground and submitted to laboratory experiments. These samples show a distinct difference in the initial bulk density, the initial level of compaction, initial void ratio, and the natural water content. The CD triaxial tests were conducted under three different levels of confining pressure; in turn, CRS tests were run with two appropriate input strain rates. According to the physical state of ASR and the depth of sampling, two different evolutions of the critical state in the stress–strain space were observed. In the light of the assessed stress–strain–strength behaviour, key design engineering parameters of ASR were calculated.

Validation of a full-plasma integrated modeling approach on ASDEX Upgrade

In this work we present the extensive validation of a refined version of the integrated model based on engineering parameters (IMEP) introduced in reference (Luda et al 2020 Nucl. Fusion 60 036023). The modeling workflow is now fully automated, computationally faster thanks to the reduced radial resolution of the TGLF calculation, and it includes the modeling of the toroidal rotation, which was still taken from experimental measurements in our previous work. The updated model maintains the same accuracy as its previous version when tested on the cases presented in the initial publication. The confined plasma, from the magnetic axis to the separatrix, is simulated without using any experimental information from profiles measurements, and the inputs of IMEP are the same engineering parameters used when programming a plasma discharge. The model validation database consists of 50 ASDEX Upgrade (AUG) stationary (over a few energy confinement time) H-mode phases, which largely cover the entire AUG operational domain. The prediction of IMEP is compared with experimental measurements and with scaling laws, such as the IPB98(y,2), the ITPA20-IL, and AUG specific regressions. This modeling framework has proven to be very accurate over the entire set of 50 cases, with a significantly lower mean relative error with respect to each of the scaling laws considered, accurately reproducing the change in pedestal and core confinement caused by a change in plasma current, heating power, fueling rate, triangularity, magnetic field, NBI voltage (i.e. the effect of a change in the core particle source), and heating mix (e.g. correctly predicting the effect on confinement caused by a change in T e/T i). Plasma confinement is correctly described by IMEP also for two particular operating regimes, such as the ITER baseline scenario, and the QCE regime (quasi continuous exhaust, also referred as type-II and small ELMs). This work clearly demonstrates the power of this approach in pulling out physics mechanisms to interpret subtle interdependencies and that a 1D integrated model can reproduce experimental results over very large parameter variations with a higher accuracy than any statistical regression. This approach has therefore the potential to improve the prediction of the fusion performance in future tokamak reactors.

Research on the Percolation Mechanism of Perturbation Under Simultaneous Fracturing in Shale Reservoirs

Compared with conventional reservoirs, shale gas reservoirs usually have no natural productivity or lower productivity, and the rate of production decline is high in the later stage. The production of shale gas can be effectively improved by designing reasonably or fracturing. Therefore, it is critical for shale gas reservoir to study how to design proper parameters to make it effectively developed. Based on data of block-A region of the Zhejiang gas field, considering the contribution of rock compression to the production, the productivity formula of horizontal well at different seepage stages is deduced. Data from block-A are verified by orthogonal experiment, including gas reservoir parameters and engineering parameters. The results show that the order of reservoir parameters that affect the development of shale gas is as follows: Langmuir pressure, diffusion coefficient, cross flow coefficient, and Langmuir volume; the order of engineering parameters that affect the development of shale gas is as follows: number of fractures, horizontal section length, production pressure, fractures length, row spacing, and well spacing. The research results have been applied to the Zhejiang gas field. The initial rate of decline after adjustment is reduced by 26.08% and production increases by 17.06% after stabilization compared to wells without adjustment parameters. The research has important reference significance for the efficient development of similar gas reservoirs.

Thermophysical characteristics of gas-power dual-fuel engines w12v50 df for liquefied gas shipping vessels

Maritime transport plays important role in the economic development of society – 90% of goods are transported by ships. At the same time, maritime transport requires a significant amount of fuel resources. Production of liquefied natural gas (LNG) is becoming the fastest growing industry in the modern global energy sector. Today, LNG accounts for 40% of the physical volume of world gas trade, and its share will increase up to 60% by 2040. Currently, natural gas is used on ships in the form of liquefied petroleum gas, compressed natural gas, and liquefied natural gas (LNG). The article deals with the urgent problem of operation of dual-fuel diesel-electric installations of ships. The need to study the heat-engineering parameters of two-fuel diesel generators of the Wartsila company has been substantiated. The authors present the dependencies of main heat-engineering parameters on the load of Wartsila W12V50DF dual-fuel engines used as a generator drive in the main electric propulsion engines on LNG tankers. A comparative assessment of the dependencies of exhaust gas temperature, turbocharger rotation speed, boost pressure and gas pressure on the load of diesel generators on two LNG tankers has been carried out. The article analyzes the presented dependencies. The authors substantiate the need for further improvement of their design and workflow.

Real-time analysis and forecasting of the microseismic cloud size: Physics-based models versus machine learning

The spatiotemporal distribution of hydraulic fracturing microseismicity is complicated and depends on various mechanical and diffusional parameters. Hydraulic fracture modeling can aid in understanding fracture propagation and microseismicity. Nevertheless, the complex spatial and temporal interaction of several processes occurring within and around the fracture represents a challenge for developing real-time tools for microseismic prediction. Two approaches were developed to forecast the microseismic cloud size in real-time. The first approach uses fracture propagation models to derive the cloud size directly from the microseismic observations. The second approach is based on a convolutional neural network (CNN) trained with the engineering parameters and past microseismic cloud size values. A rolling-forecasting strategy is employed to train consecutive CNN models in real-time to make predictions at a specified time lag. A data augmentation technique known as double noise injection is used to ensure that the amount of training examples available to the machine learning models at each time step is similar or larger than the number of free parameters. Results show that the CNN outperforms the quality of predictions of the physics-based models but with a reduced prediction capability. The physics-based approach can predict growth at any time but ignores the engineering parameters. In addition, the physics-based methods lead to real-time insights into the fracturing regime, revealing whether microseismicity is most likely generated due to a leak-off-dominated or a storage-dominated regime. The CNN model can forecast the cloud size only at a single future time lag while using the engineering parameters and past cloud growth as input. However, this approach does not provide a physical interpretation of the fracture propagation regime. The prediction accuracy of both methodologies varies depending on the microseismic behavior. We postulate that the CNN forecasts could be improved by including more physical constraints into the predictive model.