Rock Thickness Identification by XGBoost with Logging Data

Based on research on the response mechanism of rock formations and reservoirs to logging curves, 12 logging curves selected by combining the depth characteristics of formations are proposed to identify rock formations and reservoirs using four algorithms: logistic regression (LR), support vector machine (SVM), random forest (RF) and XGBoost. Out of 60 wells in the study block, 57 wells were selected for training and learning, and the remaining 3 wells were used as prediction samples for testing the algorithm. The recognition of rock formations and reservoirs is performed by each of these four machine learning algorithms, and predictive knowledge is obtained separately. It was found that the accuracy of the 4 algorithms for rock formation and reservoir layer identification reached over 90%, but the XGBoost algorithm was found to be the best in terms of the 4 scoring criteria of F1-score, precision, recall and accuracy. The accuracy of rock formation identification could reach over 95%, and the correlation analysis between the logging curve and rock formation could be performed on this basis. The results show that the RMN, RLLD and RLLS have the most obvious responses to the sandstone layer, off-surface reservoir and effective thickness layer, and the CAL has the least effect on the formation and reservoir identification, which can provide an effective reference for the selection and dimensionality reduction of the subsequent logging curves.

Construction Materials and Dam Foundation While Memve’ele Dam Building in the Craton’s Region of South Cameroon

This chapter mainly focuses on engineering geology for dam construction from the Memve’ele region in Cameroon. Here, it deals with geotechnical and geological proprieties of both construction and dam foundation materials. This study is done at the aim to ensure that these materials need to be improved and how they have been used during dam construction. Field investigations, borehole information, density and seismic velocity measurements have been used, and results indicate that soil deposits have slightly clay content, mechanically well for dam construction and display a weak thickness layer particularly on the dam site. These conditions suggest that soil materials can be used as construction (cushion, transition layers, etc.) and foundation materials after few amendments. Ntem Formations appear weathered and fractured sometimes, though their mechanical behaviors display a good character for civil applications. However, engineering processes have been used to improve it by GIN (Grouting Intensity Number) methods. These formations have been used as construction (rip rap crushing aggregate, etc.) and dam foundation materials. Thus, this chapter contributes to highlight materials and dam foundation conditions which are crucial criteria encountered in the dam with emphasis on both theoretical study and practical application during dam construction.

Electromagnetic interference shielding with absorption-dominant performance of Ti3C2TX MXene/non-woven laminated fabrics

Electromagnetic interference (EMI)-shielding materials with remarkable shielding effectiveness (SE) based on dominant absorption are highly desirable, especially if they are also flexible and lightweight. Herein, we prepared MXene (Ti3C2TX, TX-=O,-OH,-F)-based lightweight and absorption-dominant EMI-shielding non-woven fabrics. In view of the porosity and soft properties of textiles, as well as the unique high conductivity and hydrophilicity of Ti3C2TX MXene, Ti3C2TX MXene was coated on the fiber skeleton of three different non-woven fabrics made from polyester, cotton, and calcium alginate. The conductive layer formed by Ti3C2TX MXene on the fiber led to heterogeneous interfaces. They improved the multiple reflection of electromagnetic waves among Ti3C2TX MXene sheets and then contributed to the attenuation of the electromagnetic waves. Among all the samples, calcium alginate/Ti3C2TX MXene reached a maximum SE of 25.26 dB at 12.4 GHz with the fabric thickness of 3.17 mm. Cotton/Ti3C2TX MXene achieved maximum SSEt (ratio of specific shielding effectiveness (SSE) to thickness) of 2301.95 dB cm2g−1 at 1.36 mm with a loading of Ti3C2TX MXene of only 5.77mg/cm3. Further, fabric thickness, layer number, conductivity, and substrate type were selected to analyze the EMI-shielding mechanism.

Forensic Engineering Evaluation of Excessive Differential Settlement on Compressible Clays

This forensic engineering (FE) study evaluated root cause errors associated with excessive differential settlements on a housing project constructed on top of a variable thickness layer of highly compressible clays. The structures were reported to have experienced differential settlements on the order of 2 to 10 in. across 40 ft. The FE study examined fundamental assumptions, granularity/resolution of the settlement and differential settlement analyses, and finalized grading plan vs. the conceptual grading plan used as a basis for the differential settlement predictions. The FE study found numerous discrepancies between the “idealized site” used as a basis of analysis and the “actual site” as constructed.

Stepwise coordination isomerism of 2D networks: adsorption of diiodomethane into crystals and recognition in SCSC mode

Reaction of CdI2 with C2-symmetric multidentate N-donor (L) in a mixture of ethanol and dichloromethane produces single crystals of 3CH2Cl2ˑ2C2H5OH@[CdI2L] (23.26 Å thickness layer) with a new 2D topology of...

An Additive Manufacturing Method Using Large-Scale Wood Inspired by Laminated Object Manufacturing and Plywood Technology

Wood-based materials in current additive manufacturing (AM) feedstocks are primarily restricted to the micron scale. Utilizing large-scale wood in existing AM techniques remains a challenge. This paper proposes an AM method—laser-cut veneer lamination (LcVL)—for wood-based product fabrication. Inspired by laminated object manufacturing (LOM) and plywood technology, LcVL bonds wood veneers in a layer-upon-layer manner. As demonstrated by printed samples, LcVL was able to retain the advantageous qualities of AM, specifically, the ability to manufacture products with complex geometries which would otherwise be impossible using subtractive manufacturing techniques. Furthermore, LcVL-product structures designed through adjusting internal voids and wood-texture directionality could serve as material templates or matrices for functional wood-based materials. Numerical analyses established relations between the processing resolution of LcVL and proportional veneer thickness (layer height). LcVL could serve as a basis for the further development of large-scale wood usage in AM.

MULTI-LAYER WS2 AND MOS2 BASED PLASMONIC SOLAR CELL FOR SMART ENERGY HARVESTING

One of the best challenges regarding the futuristic vision of smart-city technologies is to offer a comfortable self-governance energy, especially when it comes to electricity storage. If one wants to revolutionize a pre-existing way of living, it is inescapable to neglect basic ingredients gathered from basic physics. The topic of Metamaterials represents a key field that might be explored and thus exploited to propose unprecedented ideas for completely no-existing properties and functionalities. Unlike other ambitious techniques, with a simple stratified surface in combination with a suitable choice of materials, it is possible to propose new solar cells operating in a broad range of frequencies. In this paper, we demonstrate a manner to achieve strong coupling interaction between metallic gold nanowires with a WS2 and MoS2 multi-layer. The novelty of this work lies in the drastic stability of the effect of the thickness layer variation on both, absorption performances and the electric field distribution within the visible and near-infrared range. Accordingly, this new design may be considered of prime importance in several areas such as sensing and solar cell efficiency, to cite a few examples.

Incorporating a Ferrous Polymer Target into Elastomeric Liners for Socket Fit Sensing in Prosthesis Users

Liner-to-socket distance measurement using inductive sensing may be an effective means to continuously monitor socket fit in people using trans-tibial prostheses. A practical limitation, however, is a means to incorporate a thin uniform-thickness layer of conductive or magnetically permeable target material into the wide range of prosthetic liner products that people with limb amputation commonly use. In this paper, a method is presented whereby a 0.50-mm thickness ferrous polymer made from a SEEPS polymer and iron powder that is formed adjacent to a 0.25-mm thick non-ferrous layer of SEEPS polymer is assembled between two sheets of elastic fabric material. Bench testing showed that the fabrication procedure achieved a root-mean-square error in the thickness of this construct of 58 μm, helping to create a consistent calibration result over the entire surface. The original fabric backing of an off-the-shelf prosthetic liner was removed and replaced with the developed construct. When worn in the shoe of an able-bodied participant for 7.5 h per day for 28 days, the sensor well maintained the shape of its calibration curve at the start of wear, but a distance offset (shifting of the y-intercept) was introduced that increased during the initial approximately 12 days of wear. When the distance offset was corrected, for the primary distance range of clinical interest for this application (0.00–5.00 mm), the sensor maintained its calibration within 4.4%. Before being used in clinical application for liner-to-socket distance monitoring, new ferrous liners may need to be pre-worn so as to achieve a consistent distance reference.