Two-level intelligent modeling method for the rate of penetration in complex geological drilling process

The rate of penetration (ROP) model is of great importance in achieving a high efficiency in the complex geological drilling process. In this paper, a novel two-level intelligent modeling method is proposed for the ROP considering the drilling characteristics of data incompleteness, couplings, and strong nonlinearities. Firstly, a piecewise cubic Hermite interpolation method is introduced to complete the lost drilling data. Then, a formation drillability (FD) fusion submodel is established by using Nadaboost extreme learning machine (Nadaboost-ELM) algorithm, and the mutual information method is used to obtain the parameters, strongly correlated with the ROP. Finally, a ROP submodel is established by a neural network with radial basis function optimized by the improved particle swarm optimization (RBFNN-IPSO). This two-level ROP model is applied to a real drilling process and the proposed method shows the best performance in ROP prediction as compared with conventional methods. The proposed ROP model provides the basis for intelligent optimization and control in the complex geological drilling process.     

A side-sensitive synthetic coefficient of variation chart

Control charts for monitoring the coefficient of variation (γ) are useful for processes with an inconsistent mean (μ) and a standard deviation (σ) which changes with μ, by monitoring the consistency in the ratio σ over μ. The synthetic-γ chart is one of the charts proposed to monitor γ, and its attractiveness lie in waiting until a second point to fall outside the control limits before a decision is made. However, existing synthetic-γ charts do not differentiate between the points falling outside the upper control limit (UCL) and lower control limit (LCL). Hence, this paper proposes a side-sensitive synthetic-γ chart, where successive nonconforming samples must either fall above the UCL or below the LCL. Formulae to compute the average run length (ARL), the standard deviation of the run length (SDRL) and expected average run length (EARL) are derived using the Markov chain approach, and the algorithms to obtain the optimal charting parameters are proposed. Subsequently, the optimal charting parameters, ARL, SDRL and EARL values for various numerical examples are shown. Comparisons show that the side-sensitive synthetic-γ chart consistently outperforms the existing synthetic-γ chart, especially for small shifts. The proposed chart also consistently outperforms the Shewhart-γ chart, while showing comparable or better performance than the Exponentially Weighted Moving Average (EWMA) chart for most shift sizes, except for very small shifts. Finally, this paper shows the implementation of the proposed chart on an industrial example.     

Potential effects of ultrafiltration process and date powder on textural,sensory, bacterial viability,antioxidant properties and phenolic profile of dromedary Greek yogurt

The aim of this study was to improve textural and antioxidant capacity of dromedary yogurt using ultrafiltration process and date powder. Ultrafiltration increased total solids content of dromedary milk within the range considered optimal to develop yogurt. Texture profile of Greek yogurt fortified with date powder (GYD) improved considerably compared to control. Sample of GYD are more appealing to consumer than control. LC-ESI-MS analysis of GYD extracts allowed the identification of fifteen phenolic compounds, among which quinic acid and cirsiliol were found to be the major phenolic acid and flavonol, respectively. GYD exhibited the highest DPPH•-radical scavenging activity, Fe²⁺ chelating capacity and Fe³⁺ reducing power. The follow-up of physical and microbiological stability of GYD and control during cold storage showed that date powder significantly increased bacterial counts and decreased syneresis. Therefore, ultrafiltration and date powder could be valued as effective tool to solve the poor consistency of dromedary milk products.     

Multi-Functional Black Bioactive Glasses Prepared via Containerless Melting Process for Tumor Therapy and Tissue Regeneration

Tissue regeneration in complex lesions such as the site of tumors, bacterial infection, and sites lacking blood vessels, has been a huge challenge. Therefore, developing bioactive implantable materials with multi-functional properties such as tumor destruction, bacteria growth inhibition, and angiogenesis promotion is of great significance. In this study, black CaO-SiO₂-TiO₂ (CST) glasses are prepared through the containerless melting approach, by which heterogeneous nucleation can be avoided and thereby glass formation becomes possible via fast quenching. This approach enables the formation of trivalent titanium (Ti³⁺) without using a reducing atmosphere or reducing agents. The black CST glasses are found in this study to possess a strong ability to inhibit bacteria and tumors by their excellent photothermal and photocatalytic effects. Strikingly, these glasses also promote the formation of blood vessels and accelerate the healing of chronic wounds by the synergistic effects of the photothermal effect and Si ions. Thus, this glass system can be a promising multi-functional material for tissue regeneration in complex lesions.     

Remaining useful life prediction for degrading systems with random shocks considering measurement uncertainty

Degradation data have been widely used for the remaining useful life (RUL) prediction of systems. Most existing works apply a preset model to capture the degradation process and focus on the degradation process without shocks or constant shock effects. More generally, the actual degradation path is unobservable due to the existence of measurement uncertainty, which interferes with the determination of the degradation model. Besides, the effect of random shocks is usually fluctuating. Given these problems, a general degradation model with the random shock fluctuant effects considering the measurement uncertainty is first developed to describe the degradation process, and a two-step approach combining the arithmetic average filter and the Bayesian information criterion is adopted to identify the degradation path. Subsequently, the transfer processes of the actual degradation state and the abrupt change caused by shocks are depicted using a two-dimensional state-space model, and an expectation-maximization algorithm combined with the particle filtering is developed for parameter estimation. Furthermore, the explicit solution of RUL distribution is obtained when only considering harmful shocks, while a simulation method of RUL distribution is provided when both harmful and beneficial shocks exist. Finally, the effectiveness of the proposed method is verified by a numerical example and two practical case studies.     

Fabrication and thermo stability of the SnO2/Ag/SnO2 tri-layer transparent conductor deposited by magnetic sputtering

Using the magnetic sputtering technique, the SnO₂/Ag/SnO₂ tri-layer transparent films were fabricated on float glasses successfully. Compared with the commercial FTO (F-doped SnO₂) film, the SnO₂/Ag/SnO₂ tri-layer films have higher visible-light transmittance and better conductivity. The total thickness of the SnO₂/Ag/SnO₂ films is one third of the commercial FTO film leading to the high visible-light transmittance. The high carrier concentration of the SnO₂/Ag/SnO₂ films contributes to the tri-layer films’ low resistivity. In addition, to further improve the performance of the SnO₂/Ag/SnO₂ tri-layer films, samples were annealed under different temperatures. The results illustrate that the lowest sheet resistance (5.92 Ω/sq) and the highest visible-light transmittance (87.0%) were obtained after annealing at 200 °C. Furthermore, the thermal stability of the films could be enhanced by a multi-step annealing process due to the recrystallization effect.     

Mesoporous electroactive silver doped calcium borosilicates: Structural,antibacterial and myogenic potential relationship of improved bio-ceramics

In this work improved electroactive mesoporous Ag-doped bio-ceramics for medical usages are developed, examining their structural, electrical, in-vitro bioactivity, cell cultures and antibacterial properties against various classical pathogenic bacteria. Ag-containing mesoporous bio-ceramics (MBCs): xmol%Ag₂O - (100-x)[45.8CaO-8.4B₂O₃-45.8SiO₂] where x = 2, 5, 7.5 and 10 were synthesized through a sol-gel method. The small angle X-ray scattering and electron microscopy studies reveal the embedment of silver nanoparticles in the samples. Existence of silver as Ag⁺/Ag⁰ forms in the samples is confirmed by X-ray photoelectron spectroscopy. The N₂ adsorption-desorption analysis evidence the mesoporous structure of the samples. The electrical conductivity of samples increases from 5.4 x 10^?8 S cm^?1 for x = 2 to 1.9 x 10^?6 S cm^?1 for x = 7.5 and then decreases to 0.9 x 10^?6 S cm^?1 for x = 10 at 110 °C. In vitro bioactivity studies revealed that Ag-containing MBCs hold the bone-like hydroxyapatite formation after immersion in human blood plasma like-solution such as Dulbecco's Modi?ed Eagle's Medium. The antibacterial effect of samples against pathogenic bacteria (S. aureus, E. coli, P. monas aeruginosa, and B. cereus) increases with Ag concentration (x = 7.5) and then decreases with Ag content (x = 10). Antibacterial effect is greater for the sample with high electrical conductivity. The cell culture studies evidence not considerable cytotoxic effects for Ag-containing MBCs. Finally, the C2C12 myoblast cell culture studies reveal the significant cell growths and differentiation (myogenesis) for high electrical conducting Ag-containing MBCs.     

Effects of water and carbon dioxide pressure on the adhesion of Na2SiO3 and K2SiO3 binders on silica sand surface: Comparison of experimental data and molecular dynamics simulation

In this study, the effects of different water amounts, CO₂ blowing pressures, Na₂O:SiO₂ and K₂O:SiO₂ ratios were studied on the bonding strength of Na₂SiO₃ and K₂SiO₃ binders. It was concluded that the increase in water content had an adverse effect on the bonding strength of CO₂-hardened Na₂SiO₃ sand. The blowing pressure did not have a linear relationship with the bonding strength, but it was closely related to the diffusion coefficient of CO₂. Based on scanning electron microscopic results, it was inferred that the low strength was caused by the formation of lamellar crystals after the adhesive was hardened. It was found that the low strength was caused by the formation of lamellar crystals after the adhesive was hardened. Based on molecular dynamics simulations, different pressures and water contents had a great influence on the diffusion coefficient of CO₂ in the silicate binder system. This research provides an important theoretical background to improve the technology of CO₂-hardened Na₂SiO₃- and K₂SiO₃-bonded sands during the casting process.     

基于层次分析法的叶用甜菜种质资源观赏性评价

根据叶用甜菜品种的观赏特性,运用层次分析法初步建立叶用甜菜品种观赏价值的评价模型,包含叶梗、叶片和整体感3个方面共11个评价因子。结果表明:叶梗是评价叶用甜菜观赏价值的核心要素;叶梗色、叶梗厚、叶丛型是重要因子,分别以红、粉红、粉白叶梗,叶梗厚度厚和直立型叶丛为优良性状。利用该评价模型对8个甜菜品种进行观赏价值综合评价,筛选出‘Clnx-blush2018'、'Clnx-fen2018’和‘荷兰必久'3个观赏价值高、适于市场推广叶品种。