Miracle-dz/UniFAR-FTUs huggingface dataset:
Unloading-creep test and long-term strength study of different initial conditions of limestone

The high-slope limestone on the right bank of the Wudongde Hydropower Station dam site was considered as a research object to conduct a triaxial unloading-creep test, and then to analyze in detail the limestone’s creep characteristics under different test conditions so as to investigate the limestone’s unloading-creep mechanical properties under different unloading rates and initial stress levels. The results show that the faster the unloading rate, the greater the limestone’s axial and lateral creep rate when under the same stress state. Furthermore, the lateral creep rate is greater than the axial creep rate, indicating an apparent lateral expansion. When the unloading rate is constant, the stress difference has a significant impact on the limestone. The specific manifestation is that the greater the deviator stress, the more pronounced the limestone creep phenomenon, and the rock sample is prone to damage. The steady-state rate intersection method is employed to determine the limestone’s long-term strength, and the λ parameter is introduced to reduce the influence of the axial and lateral strain increments on the long-term strength determination during the unloading process.
Study on the mechanism of coal-rock interface hindering hydraulic fracture propagation in the process of indirectly fracturing broken soft coal seam

The abundant CBM in fractured soft and low-permeability coal is expected to be exploited by indirect fracturing coal technology. However, this technique often fails because the coal-rock interface hinders the hydraulic fractures (HFs) propagation. This article focuses on the root cause of the above phenomenon, that is, the mechanical properties of coal. Its ductile fracture-seepage relationship was deduced by the Park-Paulino-Roesler potential energy function and combining with Forchheimer equation. The elastoplastic damage-seepage relationship of coal matrix can be derived by combining damage mechanics, plastic mechanics and seepage experimental results. The numerical simulation results showed that the mechanism of the coal-rock interface hindering the HFs propagation lied in the large amount of hydraulic energy dissipation caused by ductile fracture of discontinuities and plastic damage of the coal matrix, which results in the proportion of elastic energy contributing to HFs propagation as low as 2% of hydraulic energy. However, this ratio will increase to 18%∼30% as interface friction, stress difference and injection rate increase, especially the distance between horizontal well and interface decrease. This finding is of great significance for the CBM extraction in the fractured soft and low-permeability coal through indirect fracturing coal technology.
Study of the mechanism of water inrush in karst tunnel based on transparent rock mass physical model test

Water inrush is the main geological disaster occurred during karst tunnel excavation, which will cause huge economic losses and casualties. Therefore, it is important to investigate the water inrush mechanism of karst tunnel surrounding rock mass for preventing water inrush disasters in karst tunnel construction. Herein, Xinjie Tunnel of Kaili Ring Expressway in Guizhou Province is chosen as an object, where a large water-filled karst cave may locate on the upper right side of the tunnel cross section according to the geological survey report. Then taking the typical tunnel cross section as the prototype, a three-dimensional geomechanical model of Xinjie tunnel is made by using transparent rock mass material based on similarity theory, on which laboratory water inrush physical model tests are performed. Based on laboratory physical model test results, the mechanism of water inrush in karst tunnel is investigated, from which it indicates that the groundwater mainly flows through the fissures of the tunnel surrounding rock during water inrush process, and the water inflow rate mainly depends on the initial water pressure of the water-filled karst cave. When water pressure increases from 0.1MPa to 0.2MPa, the water inflow increases by 84.4%, but the increase rate of water inflow will slow down when water pressure further increases. Compared with the previous level of water pressure, the water inflow only increases by 7.2%. Hence, in the excavation of karst tunnel, it is necessary to seal the fractures by grouting timely and release the water pressure of the karst cave for preventing water inrush accident. The research results will provide important guiding significance for the excavation of karst tunnel.
Three-dimensional crack monitoring through a transparent replica of brittle rock manufactured with fused quartz

Transparent rock-like materials have been used as a replica of natural rock to study the crack propagation mechanisms. Previous research focused on materials such as glass or transparent polymethyl methacrylate. In this paper, an alternative transparent material that is manufactured with fused quartz was presented, along with the manufacturing process and deformation behavior during a uniaxial compression test. Three digital cameras were arranged around the specimen during the uniaxial compression test to capture the cracks of the same moment from different angles for 3D reconstruction of the cracks. Results show that fused quartz has a similar deformation behavior as natural brittle rock and has potential for the reconstruction of 3D cracks in rocks for quantitative analysis of crack propagation.
Protein based biomaterials for therapeutic and diagnostic applications

Proteins are some of the most versatile and studied macromolecules with extensive biomedical applications. The natural and biological origin of proteins offer such materials several advantages over their synthetic counterparts, such as innate bioactivity, recognition by cells and reduced immunogenic potential. Furthermore, proteins can be easily functionalized by altering their primary amino acid sequence and can often be further self-assembled into higher order structures either spontaneously or under specific environmental conditions. This review will feature the recent advances in protein-based biomaterials in the delivery of therapeutic cargo such as small molecules, genetic material, proteins, and cells. First, we will discuss the ways in which secondary structural motifs, the building blocks of more complex proteins, have unique properties that enable them to be useful for therapeutic delivery. Next, supramolecular assemblies, such as fibers, nanoparticles, and hydrogels, made from these building blocks that are engineered to behave in a cohesive manner, are discussed. Finally, we will cover additional modifications to protein materials that impart environmental responsiveness to materials. This includes the emerging field of protein molecular robots, and relatedly, protein-based theranostic materials that combine therapeutic potential with modern imaging modalities, including near-infrared fluorescence spectroscopy, single-photon emission computed tomography/computed tomography, positron emission tomography, magnetic resonance imaging, and ultrasound/photoacoustic imaging.
Numerical study on mining induced mechanical behavior of a mine group controlled by a large geological body

In the present study, based on the geological information of the Yima Coalfield in Henan Province, People’s Republic of China, a numerical model composed of five mines with F16 large thrust fault and extremely thick conglomerate is constructed. Next, a self-developed parallel program, i.e. CASRock, is applied to simulate the mining process in different mines and investigate the associate mechanical behavior. The evolution of displacement, stress and plastic strain of rock mass under different mining conditions of the mine group in the Yima Coalfield are thoroughly demonstrated. The results reflect the interactions in mechanical behaviors between neighboring mines. These interactions are strengthened due to the existence of the overlying extremely thick conglomerate and F16 large fault. The stress transfer via the large geological body in large-scale goaf is the main reason for the high stress concentration of the adjacent working faces.
Numerical simulation of performance evolution of anti-seepage curtains in the high water head tunnel surrounding rock

To study the dynamic evolution process of the anti-seepage curtain under high water head, a multi-physics coupling model reflecting the time-effect of the curtain was established based on the principles of seepage mechanics, solute migration and chemical kinetics. The model is composed of a seepage model, a solute migration model, and a curtain dissolution model, which is solved by the finite element method, and verified by combining the relevant uplift pressure monitoring data. The simulation results indicate that the porosity of the anti-seepage curtain increased by 29.38% compared with the initial porosity, and the permeability coefficient increased by 1.95 times. The dissolution of the anti-seepage curtain had the characteristics of temporal and spatial variation, the dissolution extent at the middle part is much quicker than at its bottom part, particularly, there is almost no dissolution at its top part. The dissolution area near the upstream side of the anti-seepage curtain is larger than that on the downstream side. Simultaneously, the research results and monitoring data are available to evaluate the durability of the curtain, and provide a scientific basis for the safe operation and management of the power station.
The fusion of physical mechanism and artificial intelligence – A case study of water-tightness estimation for geometrically imperfect cut-off walls

Underground cut-off walls are widely used in various applications to hinder groundwater flow and contaminant transportation. Although the cut-off walls are installed with due discretion, occasional construction errors were found to be inevitable, causing significant leakage or even failures. An on-site risk assessment tool is needed, to map the input construction error and water-tightness performance of the cut-off walls quickly and accurately. Although a highly efficient physical-based algorithm (three-dimensional discretized algorithm, TDA) is developed, its calculation speed may not suffice to serve as an instant on-site evaluation tool. In this regard, a direct relationship between the random seeds of positioning errors and seepage flow rate is expected to be explored, and based on this, a surrogate model using the AI approach is established. A novel physical-based Neural Network (NN) model is proposed to train NN from a more physical and interpretative perspective. The proposed physical-based NN is reasonably accurate but much more efficient than the benchmark physical-based method (TDA), and the prediction accuracy and result interpretability is also superior than the traditional NN.
Numerical Study on Free Face-Assisted Rock Fragmentation Induced by a TBM Disk Cutter

This paper presents a numerical study on the rock fragmentation process induced by a tunnel boring machine disk cutter under different free face conditions. A grain-based discrete element method is incorporated into the particle flow code to synthesize appropriate rock samples, considering macroscopic mechanical properties and fracturing mechanisms. The influences of free face structures (height H, spacing S, and direction) on rock breaking mode, normal force, and penetration specific energy are investigated via numerical simulations. Results show that the rock breaking force and PSE of the side free face (STFF) model are significantly lower than those of the top free face (TFF) model. Based on the rock fragmentation analyses in rock breaking mode, four critical values were obtained, which can be used as the basis to design free face structures considering the rock breaking performance. The normal force significantly improves with free face spacing while the PSE is primarily influenced by free face height and rock breaking mode. These findings may be useful to understand the rock breaking mechanism of a disk cutter under free face conditions and can be used as guidance for the design of free face structures.
Age Variation of Douglas-Fir Bark Chemical Composition

The chemical composition of Douglas-fir bark was analyzed at three stem height levels of trees with different ages from two geographical locations. Cork and phloem in the bark’s rhytidome were analyzed separately at stem bottom: extractives (49.8% and 17.0%, respectively), suberin (30.1% in cork) and hemicelluloses, namely arabinose content (25.3% and. 4.8% of all monomers, respectively). Suberin composition includes α,ω-alkanoic diacids (38.6%), ω-hydroxyalkanoic acids (25.6%), alkanoic acids (18.2%), alkanols (2.2%), and aromatics (8.8%). Bark’s chemical composition is age-related, namely regarding suberin content: at 45, 30 and, 17 years of age, bark contained respectively 25.4%, 2.6%, and 0.9% of suberin; 24.5%, 33.9%, and 29.8% of lignin; and 29.4%, 20.6%, and 25.7% of extractives. This difference is due to the small number of periderms and low cork content in barks with 30 or less years. When aiming at a cork-targeted valorization, the lower stem parts of mature Douglas-fir trees should be considered while the high content of polar extractives at all stem heights allows an overall potential valorization.
Effect of peak performance nutrients on soil chemical properties and nutrient uptake by rice (oryza sativa L.)

The effects of peak performance nutrient (PPN) in combination with different fertilizer doses on soil properties and nutrient uptake by rice were investigated in a field experiment from seedling to maturity during the period of July to November 2014 in T. aman season. The experiment comprised of twelve treatments laid out in a randomized complete block design with three replications. The treatments were: T1: Control (no fertilizer and no PPN), T2: 100 % recommended dose of NPK, T3: 100 % NPK + PPN, T4:0 % RD +PPN only, T5: 75 % N + 100 % PK+PPN, T6: 50 % N + 100 % PK+PPN, T7: 75 % P+100 % NK + PPN, T8: 50 %P + 100 % NK + PPN, T9: 75 % K+ 100 % NP + PPN, T10: 50 % K + 100 % NP + PPN, T11:75 % NPK+ PPN, T12: 50% NPK+PPN. Experimental results reveal that the highest nutrient uptake (N and K) uptake by rice grain and straw was recorded in the treatment T7. However, P uptake by rice grain and straw were higher in treatment T3 that was statistically similar with treatment T7. Initial and postharvest soil sample analysis indicated that most of the studied soil properties including soil pH and organic matter contents were increased in T7. Therefore, the treatment combination PPN along with 75 % P+100 % NK (T7) was found to be more suitable compared to other treatment combinations for improving soil quality as well as enhancing nutrient uptake by rice. Thus peak performance nutrient (PPN) showed a positive response both on improvement of soil health as well as nutrient uptake by the crop.
Effect of tamoxifen treatment on the epidermal growth factor receptor expression in the mouse ovarian tissue

The objective of this study was to investigate the effect of Tamoxifen (TAM) treatment on epidermal growth factor receptor (EGFR) expression in the pubertal mice ovary. In this study, 80 female mice (8 week-old) were used. Animals divided four groups; non-injected (control A), injected with TAM’s vehicle solution (control B). The mice in groups TAM 0.5 and TAM 1.5 were treated with tamoxifen at a dose 0.5 and 1.5 mg/mouse/day respectively. TAM was dissolved with 10% ethanol: 90% corn oil. Mice were given daily subcutaneously injections for 5 days. Ovarian sections were immunostained with EGFR antibody and triple staining for examine the general structure. We observed that follicular atresia was increased, follicular cysts were formed in stroma, and interstitial cells were increased with TAM dose treatment. In the present study, there were no significant differences in the EGFR expression in mouse ovary of all groups. EGFR expression was not determined in the granulosa cells. While strong EGFR immunoreaction was observed in the interstitial cells and oocyte cytoplasma, weak EGFR immunoreactions was observed in theca cells of follicles. As a result, it was observed that the administered doses of TAM have not significant influence on EGFR expression.
Earnings Management

Oftentimes managers in an organization are motivated by some objectives. Accounting systems have many flexibilities and managers take advantage of this flexibilities through private information. Opportunities also lead managers to adopt earnings management approach. In a dark sense, earnings management means adoption of process to misrepresent financial report or reduction of transparency of such information. In a broad sense, earnings management means use of accounting systems either to provide misinformation to shareholder or enhance the accounting number where there is an incentive on that information. In the world of accounting, imperfect information is everywhere. Earnings management is a result of imperfect information. The aim of this essay is to shed a light on what earnings management is, accruals and earnings, earnings and valuation, how to detect earnings management, choice of accounting method and timing, discretionary accruals, where to look for to detect earnings management, asset pricing motivation, contractual motivations, and finally concluding the easy with some interesting findings on earnings management.
Efficient Multi-Path Protocol for Wireless Sensor Networks

Wireless sensor networks are useful for streaming multimedia in infrastructure-free and hazardous environments. However, these networks are quite different from their wired counterpart and are composed of nodes with constrained bandwidth and energy. Multiple-path transmission is one of the methods for ensuring QoS routing in both wired and wireless environment. Directed diffusion, a well known wireless sensor network protocol, only routes packets through a single path, which barely meets the throughput requirement of multimedia data. Instead, we propose a multipath algorithm based on directed diffusion that reinforces multiple routes with high link quality and low latency. This algorithm retains the merits of the original directed diffusion algorithms, including its energy efficiency and scalability. A hybrid metric of link quality and latency is used as the criterion for path selection. In order to select disjoint paths, we propose a scheme for reinforced nodes to respond negatively to multiple reinforcement messages. We use the NS-2 simulation tool with video trace generated by Multiple Description Coding (MDC) to evaluate the performance. The results show that our algorithm gives better throughput and delay performance, i.e. higher video quality, than standard directed diffusion that transmits over a single path, with low overheads and energy consumption.
Household Indebtedness and the Consumption Channel of Monetary Policy: Evidence from China

This paper studies the impact of household indebtedness on the consumption channel of monetary policy using the Chinese household-level survey data. We employ a panel smooth transition regression model to investigate the non-linear role of indebtedness. We find that housing-related indebtedness weakens the monetary policy transmission, and this effect is non-linear as there is a much larger counteraction of consumption in response to monetary policy shocks when household indebtedness increases from a low level rather than from a high level. Moreover, the weakened monetary policy transmission from indebtedness is stronger in urban households than in rural households. This can be explained by the investment good characteristic of houses in China.
Not Negotiable? The Gender Gap in Startup Valuation and its Remedies

We explore whether the established gender gap in entrepreneurial finance also extends to startup valuations. This study uses a comprehensive sample of 966 performance observations including all pre-money valuations of 106 venture capital (VC) funded startups in the high-tech industry from European and Latin American markets. We find that startups with female CEOs receive significantly lower valuations than firms with male CEOs after controlling for a wide range of startup characteristics. We build on the role congruity theory and explore the potential moderation effects of the self-initiation and negotiation experience on gender bias in VC deals. We find that in case of female-led startups, self-initiation aggravates the gender gap in their valuations, while negotiation experience mitigates the gender gap. Further, our results show that the gender bias on the investors' side plays a stronger role in the gender gap in valuations than that on the founders' side.
Using egg ovalbumin to synthesize pure α-Fe2O3 and cobalt doped α-Fe2O3: structural, morphological, optical and photocatalytic properties

Nanoparticles of undoped hematite (α-Fe2O3) and Co doped α-Fe2O3 were prepared by a simple, green, and cost-efficient process using Co and Fe chlorides and freshly isolated hen egg white. Several techniques of characterization, such as differential thermal and thermogravimetric analysis (DTA/TG), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), EDS analysis, X-ray diffraction analysis (XRD), and Ultra-violet Visible (UV–Vis) analysis were applied. The incorporation of Co particles into the hematite matrix limits the growth of the α-Fe2O3 crystalline grain and favours the apparition of γ-Fe2O3 phase. SEM analysis reveals that there are no significant morphological differences among α-Fe2O3 and Co-α-Fe2O3 particles, whereas the XPS analysis confirms the existence of Fe and Co particles in the as-prepared samples. The optical study shows a slight reduction of band gap energy for Co doped α-Fe2O3 compared to the non-doped α-Fe2O3, which has shown enhanced visible light adsorption performance. On the other hand, the α-Fe2O3 and Co-α-Fe2O3 nano-photocatalysts with an average crystallite size of 21 and 43 nm respectively, were used to remove the Methylene Blue (MB) dye from aqueous solutions after being exposed to visible light. In a mechanistic study, the radicals OH• and •O2− were shown to be important in the degradation of MB dye. To optimise the effective parameters on MB dye degradation, the experimental parameters applied in the adsorption experiments, such as pH, photocatalyst dosage, contact time, and temperature, were tested. The optimal conditions were determined as pH = 12, photocatalyst dosage = 0.2 g/L. Degradation efficiency in the optimal conditions is 91.8 % after 120 min of irradiation. The pseudo-first and second orders were used to model the kinetic data. The removal of MB using α-Fe2O3 and Co-α-Fe2O3 photocatalysts matched well with pseudo-second-order reaction kinetics. Furthermore, the thermodynamic study reveals that MB dye adsorption on the Co-Fe2O3 absorbent was an endothermic and spontaneous process.
Ownership change and banking efficiency in the new EU members

The aim of this study is to analyze how European integration and, especially, changes in ownership, has affected banking efficiency in Central and Eastern European countries which have recently experimented this process more intensely. Using a stochastic frontier approach (SFA) applied to panel data, we have estimated bank efficiency levels in a sample of 189 banks from 12 countries during the period 2000 to 2008 and we have analyzed the influence of some bank characteristics on these efficiency levels. The results show that European integration has significantly improved the cost efficiency of banks in these countries but profit efficiency has significantly decreased. We have found very small differences between different ownership types and only a very small impact of foreign ownership on cost efficiency, showing that the entry of foreign ownership is not enough to explain the significant variations in banking efficiency after the accession.