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The safety and efficiency of drilling engineering are greatly impeded by destructive vibrations of drill string in air drilling, such as stick-slip, bit-bounce and their coupled vibrations. To avoid or suppress these vibrations improving the stability of drilling operations, revealing the occurrence mechanisms of abovementioned harmful vibrations are indispensable by investigating dynamics characteristics of drill string system. In this paper, an axial-torsional coupled dynamics model that can capture the motion behaviors of bottom hole assembly (BHA) is established adopting the lumped parameter method. Subsequently, a rate of penetration (ROP) model appropriating for air drilling is obtained firstly by linear fitting means. Meanwhile, a novel discontinuous support model is established to describe the bit-formation interactions. Then, BHA dynamics are discussed using numerical simulations under different vibration scenarios: normal operation; stick-slip; bit-bounce; bit-bounce and stick-slip combination. Subsequently, in two drilling modes: the continuous and intermittent drilling, the vibration mitigation strategies and dynamics sensibility study of BHA are carried out based on the parametric analysis. The results show that increasing torsional stiffness of drill-pipes, appropriately adjusting rotation speed of top driven system and dynamic weight on bit (WOB) are deemed as an effective strategy suppressing or eliminating stick-slip and bit-bounce vibrations of BHA. Suggest that the rotation speed of top driven system and dynamic WOB are 5 rad/s and 3.5 kN, respectively. Finally, the constructed probability maps allow to driller to choose reasonable mechanical parameters, thereby realizing smooth drilling operation in the air drilling.

The Sommerfeld effect is a phenomenon in which a non-ideal prime mover fails to provide enough energy around the resonance speed in a vibration system, resulting in resonance capture and a nonlinear jump. This study discusses the successful techniques for attenuating the Sommerfeld effect in a vibration system with four degrees of freedom (DOFs) driven by a non-ideal induction motor. The kinetic equations of the system are derived using the Lagrange function. Additionally, the mean rotational speed and stability of a non-ideal motor are studied by energy balance and perturbation analysis method. Then, the relationship between electromagnetic torque and motor speed in the Sommerfeld effect is analyzed. The Sommerfeld effect exists near the natural frequencies (NFs) with electrical frequency increased or decreased. The main reason is that the gradually increasing mechanical load power of the vibrating system near the NFs contradicts the finite electromagnetic output power of the non-ideal induction motor. Moreover, the validity of the proposed methods is demonstrated through numerical analysis and simulation. The Sommerfeld effect can be effectively mitigated by appropriately increasing the damping coefficient, reducing the installation distance, and minimizing both the eccentric mass and eccentricity radius of the rotor.

Abstract Protein function annotation has been one of the longstanding issues in biological sciences, and various computational methods have been developed. However, the existing methods suffer from a serious long-tail problem, with a large number of GO families containing few annotated proteins. Herein, an innovative strategy named AnnoPRO was therefore constructed by enabling sequence-based multi-scale protein representation, dual-path protein encoding using pre-training, and function annotation by long short-term memory-based decoding. A variety of case studies based on different benchmarks were conducted, which confirmed the superior performance of AnnoPRO among available methods. Source code and models have been made freely available at: https://github.com/idrblab/AnnoPRO and https://zenodo.org/records/10012272

The severe vibration of BHA directly affect the drilling efficiency, borehole trajectory, and wellbore quality. Therefore, it is crucial for developing dynamic mechanics of drill string system by studying the mechanical behavior of BHA. In this paper, considering the continuity condition of double-span drill collar, the expression of lateral vibration of drill collars is firstly obtained by using the assumption mode method. Then, the lateral vibration equation of double-span drill collar is derived by Lagrange equation. Finally, a self-programming model is established based on dynamic mechanics of drill string system, the lateral vibration characteristics of double-span drill collar in four different types of BHA is further determined by the fourth-order Runge-Kutta algorithm. It is obviously found that the lateral vibration is enhanced with increasing the length of drill collar; the rotation speed of BHA, weight on bit (WOB), and the size of stabilizer have a significant influence on the lateral vibration of drill collar. In the practical application, the lengths of the first-span and the second-span drill collar are given as 10 and 19 m, respectively; and the stabilizer diameter approached to bit diameter is recommend in practical gas drilling engineering; under WOB of 10–40 kN, the rotation speed of the drilling string should be controlled nearby 60 r/min. The theoretical investigation is a guidance for structure design of BHA and optimization of drilling parameter.

Polypeptoid-coated surfaces and many surface-grafted hydrophilic polymer brushes have been proven efficient in antifouling-the prevention of nonspecific biomolecular adsorption and cell attachment. Protein adsorption, in particular, is known to mediate subsequent cell-surface interactions. However, the detailed antifouling mechanism of polypeptoid and other polymer brush coatings at the molecular level is not well understood. Moreover, most adsorption studies focus only on measuring a single adsorbed mass value, and few techniques are capable of characterizing the hydrated in situ layer structure of either the antifouling coating or adsorbed proteins. In this study, interfacial assembly of polypeptoid brushes with different chain lengths has been investigated in situ using neutron reflection (NR). Consistent with past simulation results, NR revealed a common two-step structure for grafted polypeptoids consisting of a dense inner region that included a mussel adhesive-inspired oligopeptide for grafting polypeptoid chains and a highly hydrated upper region with very low polymer density (molecular brush). Protein adsorption was studied with human serum albumin (HSA) and fibrinogen (FIB), two common serum proteins of different sizes but similar isoelectric points (IEPs). In contrast to controls, we observed higher resistance by grafted polypeptoid against adsorption of the larger FIB, especially for longer chain lengths. Changing the pH to close to the IEPs of the proteins, which generally promotes adsorption, also did not significantly affect the antifouling effect against FIB, which was corroborated by atomic force microscopy imaging. Moreover, NR enabled characterization of the in situ hydrated layer structures of the polypeptoids together with proteins adsorbed under selected conditions. While adsorption on bare SiO2 controls resulted in surface-induced protein denaturation, this was not observed on polypeptoids. Our current results therefore highlight the detailed in situ view that NR may provide for characterizing protein adsorption on polymer brushes as well as the excellent antifouling behavior of polypeptoids.

High-fill culverts placed in valley topography have a complex earth pressure distribution law due to their locations around culverts in various valley topography conditions. In order to investigate the influence of valley topography on the earth pressure around the culvert of high-fill arch culverts, an interaction model of "topography-culvert-fill" was established by using centrifugal model test and numerical simulation method. Additionally, the distribution laws of earth pressure around the arch culverts and earth pressure concentration coefficient Ks at the top of the culvert under different valley widths B and valley slopes α were analyzed and were compared with the latest Chinese culvert design code. Furthermore, the mechanism of earth pressure formation of high-fill arch culverts under valley topography was presented. The research findings are as follows: (1) The influence of the valley width B on the earth pressure concentration coefficient Ks at the top of the culvert is significant, and the increment of the earth pressure concentration coefficient Ks at the top of the culvert is larger when B is 4D−6D（D is the clear span of arch culvert）. (2) When B is less than 4D, the topography would play the role of load reduction to the culvert. (3) With valley slopes ranging from 45° to 60°, the earth pressure at the tops and Ks would be affected dramatically. (4) When fill height is 20 m with α >70°, Ks≤1; and when 40 m fill height with α >50°, Ks≤1. (5) The Ks recommended by the latest Chinese culvert design code differs to some extent from those by centrifugal model test and numerical simulation. In the case of α =45° with a small B value, the earth pressure concentration coefficient Ks at the top of a culvert of the code is more conservative. (6) Ks of high-fill arch culvert in valley is related to the formation of arch top compaction area and isobaric surface. The arch top compaction area can cause the earth pressure concentration on the top of the arch culvert, and cause the vertical earth pressure of the soil around the compaction area to be arched. At a certain depth approaching the surface of the fill, the arch distribution gradually transits to the horizontal distribution, thus forming an isobaric surface. The upper load of the isobaric surface will be dispersed on the valley slope, so the unloading effect of the valley topography can be exerted.

Purpose: The pain threshold index (PTI), a novel index of nociception based on spontaneous EEG wavelet analysis, has been reported to provide reliable accuracy for predicting postoperative pain and hemodynamic reactivity. The present study is aimed to investigate whether PTI-guided analgesia reduces the pain intensity and rate of remedial analgesia in the post-anesthesia care unit (PACU). Methods: A total of 122 females undergoing elective gynecologic surgeries had been randomized to receive either PTI-guided analgesia (PTI group) or standard clinical care (control group). Remifentanil administration in the PTI group was guided by PTI to maintain the value between 40 and 65, while that in the control group was guided by hemodynamic changes. The primary outcome was remedial analgesia rate in the PACU. The postoperative pain scores, intraoperative remifentanil requirements, opioid-related adverse events and perioperative serum stress hormone concentrations between the two groups were also compared. Findings: It was found that 23 of 58 patients (40%) in the control group and 8 of 58 patients (14%) in the PTI group needed remedial analgesia. The relative risk of receiving remedial analgesia was 2.88 (95% CI, 1.40–5.89, P = 0.002) in the control group. Sufentanil consumption in the PACU (μg) was lower in the PTI group (P = 0.002) than in the control group. Remifentanil and propofol consumption, opioid-related adverse events between these two groups were comparable. Implications: PTI-guided analgesia during gynaecologic operations resulted in 25.87% less remedial analgesia. However, studies with different PTI thresholds and larger, more diverse populations should be conducted to further demonstrate the clinical effectiveness of PTI.

2D hybrid perovskites have emerged as a promising alternative material to address the environmental stability and the ion‐migration of the 3D perovskites for direct X‐ray detector applications. Nevertheless, the X‐ray detection performance of the 2D hybrid perovskites still lags because of its low X‐ray attenuation ability and limited solubility for thick film deposition. Here, a high‐performance X‐ray detector in Dion‐Jacobson 2D hybrid perovskite, 2(aminomethyl) pyridinium lead bromide (2AMPPbBr4), is studied. 2AMPPbBr4 exhibits an ultra‐short interlayer distance of 3.43 Å, leading to high X‐ray attenuation ability. Furthermore, DFT results indicate that 2AMPPbBr4 exhibits type II band alignment between 2AMP2+ ligand and the [PbI6]4− layers, facilitating effective spatial separation of photo‐generated carriers. The X‐ray detector made of 2AMPPbBr4 with an average thickness of 200 µm is realized via an improved drop‐casting method. An improved X‐ray sensitivity of 3933.88 µC Gy−1 cm−2 and a low detection limit of 4.17 nGy s−1 is achieved. This work paves the way for high‐performance X‐ray detectors based on the emerging 2D perovskite materials. [ABSTRACT FROM AUTHOR]

During the drilling of shale gas wells, the shape of shale cuttings cut by polycrystalline diamond compact bits has an obvious flaky structure. The accumulation of such flaky cuttings is one of the main reasons for high drilling torque and drag and serious back pressure, which affect the drilling speed of the horizontal section of shale gas wells. Therefore, predicting the thickness of the flaky cuttings bed and restraining it are essential for ensuring safe and efficient drilling of the horizontal section of shale gas wells. However, most of the previous research on migration laws for cuttings were based on spherical particles, which affected the accuracy of cuttings bed thickness prediction. In this study, through visualization experiments combined with computational fluid dynamics numerical simulation, the hole cleaning laws of shale gas wells in the long horizontal section were studied, and a set of cuttings bed thickness prediction models and cuttings bed removal process parameter optimization methods were established. Field application was conducted in the Changning 209H24-1 well in the southern Sichuan Basin, China. The results revealed the following: (1) There are significant differences in the migration laws of flaky cuttings and spherical cuttings in the horizontal section. (2) The fitting accuracy of the established long horizontal fragmentation layer distribution model considering multiple factors and the experimental data is as high as 0.973. (3) Based on this model, the drilling parameters of the Changning 209H24-1 well were optimized, which played a good role in wellbore cleaning and ensured the safe and smooth implementation of the later casing operation.

Myofascial as a holistic structure emphasizes a holistic approach to intervention and treatment of fascial-related disorders such as neck pain (NP), low back pain (LBP), and knee pain. There are currently adverse effects of medication for diseases related to myofascial. Traditional Chinese rehabilitation exercise (TCRE) is a practical approach to traditional Chinese medicine and is a valuable option for intervening in myofascial-related pain. This article found some research evidence for Baduanjin, Wuqinxi, and Yijinjing in clinical studies of myofascial chain-related pain. The article summarizes the current evidence and finds that TCRE can enhance limb movement function through breathing and slow movements, increase joint movement and flexibility, and reduce joint pathology and stress-induced pain. As for future directions, focus on TCRE in improving the health of older adults and treating long-COVID syndrome, and integrate robotic and TCRE training to frame safe and effective exercise models. Relevant studies have already been registered in the Clinical Trials Registry, and some clinical study protocols have been published. TCRE can be an alternative nonpharmacological rehabilitation therapy to alleviate chronic rheumatic pain symptoms and augment public health management. [ABSTRACT FROM AUTHOR]

The buckling behavior of tubular string is critical for safe oil and gas resource development. In practical engineering, the buckling of tubular string can appear in different development phases, such as casing putting into wellbore, BHA drilling rock, pipeline buckling, etc. Therefore, in this paper, the buckling behavior and buckling evolution of the tubular string are explored considering friction in horizontal wells. By applying the principles of static equilibrium and beam-string theory, an established theoretical model is utilized to examine the buckling behavior of tubular string. The critical load for sinusoidal buckling is determined by using both the series and trial function methods, and a comparison is made between the results obtained from these two techniques. In addition, perturbation analysis is used to obtain the angular displacement's configuration function in the helical buckling post-buckling state. To validate the model's effectiveness, a comprehensive analysis of the numerical results is performed, considering both sinusoidal and helical buckling scenarios. The research findings demonstrate that both the series method and the trial function method can effectively analyze sinusoidal buckling with high accuracy. The presence of friction significantly impedes the buckling behavior of the tubular string. Moreover, friction's influence causes a gradual decline in the efficiency of transmitting axial forces along the wellbore axis. [ABSTRACT FROM AUTHOR]