Lifting Method Research Articles

Research trends and mapping knowledge for maxillary sinus augmentation in oral and maxillofacial surgery

BackgroundThe method most frequently employed to alleviate the deficiency of vertical bone volume in the maxillary posterior region is maxillary sinus augmentation. Given its importance in the field of dental implants and its possible impact on implant survival, it is crucial to assess the caliber and bibliometric characteristics of research related to maxillary sinus augmentation. This study aimed to understand the development and trends of studies and guide future studies by performing a bibliometric analysis of research related to maxillary sinus augmentation. MethodsThe Web of Science database was searched on 29.05.2024 with the developed search strategy. Articles were listed in descending order according to the number of citations and analyzed using the Bibliometrix program prepared in R base. The articles were analyzed in four sections: performance analysis, word analysis, collaboration analysis, and thematic analysis. ResultsWang HL is the most frequently listed author on this topic with 24 h-indexes and 1686 total citations. The highest number of articles were published in 2017, with 102 articles with an average of 2.7 citations. The most popular keyword was "dental implants." with 426 usages. Italy and the USA are the countries that have published the most collaborative papers. Clinical Oral Implants Research comes at the top when evaluating the journals that publish on maxillary sinus augmentation based on the h-index. Basic research and technical-oriented studies between 1999 and 2005 have given way to more clinical and patient-oriented research. ConclusionThis bibliometric study will serve as a guide for future research by illustrating the existing state of knowledge and limitations regarding the development of sinus lifting methods, given the constantly growing demand for implant therapy.

Analysis Clarifies Failures of Gas Lift Valves in Subsea Wells

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 215010, “Failure Analyses of Gas Lift Valves That Caused Improper Tubing/Annular Communication in Subsea Wells,” by Sebastião T.X. Bastos, Galileu P.H. Oliveira, and Tatiana Sanomya, Petrobras, et al. The paper has not been peer reviewed. _ This work presents the results of several failure analyses of gas lift valves (GLVs) retrieved from the operator’s subsea wells. These valves were unable to prevent backflow from tubing to annulus, thereby compromising well integrity. These investigations allow a more-precise diagnosis of GLV failures that tends to reduce the risk of problem recurrence and can guide the correction of fragilities in current designs. They also can contribute to better planning and definitions in future well completions, resulting in increased reliability for this method of artificial lift. Failure-Analysis Procedure Usually, GLV failures are detected in tubing-integrity tests. Every time a leak rate above the limits for surface-controlled subsurface safety valves is registered in such an integrity test, a procedure is performed to try to restore the sealing capacity of the GLV by flushing the valve with diesel. Then, another tubing integrity test is performed. When removing a supposedly failed GLV from a well, special care must be taken at the rig to preserve the equipment, retaining its condition inside the well as much as possible. For this reason, the following recommendations are prescribed: - The GLV, and any material adhered to any part of its body, must not be washed. - If parts of the valve, debris, or any material adhered to the valve detach from its body, they shall be collected, placed inside clean plastic bags, and shipped along with the valve for failure analysis. - Equipment packaging requires placement in a proper box for transportation after bubble-wrapping the valve’s body and detached parts. - Equipment storage and transportation shall preserve its original conditions. - Mechanical shocks must be avoided. The failure analysis itself occurs at the valve’s manufacturing shop and must be witnessed by at least two specialists from the operator. A database on GLV failures is kept and provides statistical data and general information on these incidents. This procedure constantly has been subject to changes as new lessons learned point to the incorporation of improvements. For instance, the requisite for not cleaning the GLV at the rig came after observing that deposits could have been removed in the process. Also, more recently, some questions have been raised regarding the execution of the leakage test at the beginning of the inspection at the shop, because such tests could interfere with the position of the GLV’s internals or displace or disarray any deposited material. Thus, this step has been discontinued unless a good reason exists to suppose that the valve internal seals are functional. Failure-Analysis Excerpts The complete paper presents seven cases of failure analysis (four are included in this synopsis) for GLVs retrieved from subsea wells in recent years, accompanied by a short description of the facts of the case. Ordinary actions and events are omitted for brevity.

The Influence of Gas Lift on Oil Drainage Area in Reservoirs

Abstract Gas lift is a widely employed artificial lift method in the oil and gas industry, with the potential to significantly impact oil recovery from reservoirs. This study investigates the effect of gas lift on the oil drainage area within reservoirs, aiming to enhance our understanding of its role in reservoir management. Using advanced reservoir engineering and simulation techniques, the research explores the dynamics of gas lift and its influence on the accessibility of hydrocarbon resources. The study provides a comprehensive analysis of gas lift parameters, including gas injection rates, depths, and configurations, and their collective impact on the drainage area. It also considers the interplay between gas lift operations and reservoir characteristics such as permeability, porosity, and fluid properties. Findings from this study reveal that gas lift can effectively expand the drainage area by reducing bottomhole pressures and facilitating the movement of oil within the reservoir. This expansion enables the recovery of hydrocarbons from previously untapped regions, resulting in improved oil production. The research underscores the importance of optimizing gas lift design to maximize reservoir performance. Additionally, the study addresses operational challenges associated with gas lift, including gas allocation, injection optimization, and equipment reliability. It provides insights into the economic and operational considerations of gas lifts, offering valuable recommendations for reservoir management. The outcomes of this research contribute to a deeper understanding of how gas lift influences the oil drainage area in reservoirs, providing valuable insights for reservoir engineers, operators, and industry professionals involved in oil production. This knowledge supports informed decision-making to optimize oil recovery, reservoir performance, and the efficient use of gas lift technologies.

Unsung Hero: Artificial Lift Boosts Production Without Breaking the Bank

_ In the quest to cost-effectively boost production, operators are experimenting with artificial lift methods and how digital tech can boost its performance. Artificial lift experts are increasingly adding artificial intelligence (AI), machine learning (ML), and autonomous operations into their workflows because these data-driven technologies are demonstrating they can generate uplift when they are thoughtfully developed and deployed. Operators are also looking at the performance of high-pressure gas lift (HPGL) wells compared to wells using electrical submersible pumps (ESPs) for artificial lift. Finally, operators sometimes have to decide whether to risk replacing equipment that seems to be functioning, even if at subpar levels, in a bid to increase production. Digital Boost Optimized gas lift workflows and autonomously implemented ESP set points are helping ExxonMobil and Vital Energy produce more oil. Gas lift is a popular artificial lift method partly because the system is simple, robust, and inexpensive to operate, but optimizing it has historically been time-consuming. SPE 219553 outlines ExxonMobil’s approach to automating gas lift optimization for wells in the Permian Basin. The resulting workflow, which relies on AI and ML, generated a 2.2% uplift in production at the more than 1,300 wells where it was deployed, without requiring changes to surface or downhole equipment or generating additional work for personnel. Derek Burmaster, production optimization engineer for ExxonMobil Upstream Integrated Solutions, said during SPE’s Artificial Lift Conference and Exhibition (ALCE) in August that one of the big benefits of applying the closed-loop iterative well-by-well gas lift optimization workflow is that it removes the need for an engineer or specialist to have to go into the field repeatedly to change injection rates and analyze the well’s data. “For each well, that might take a few hours, at least,” he said. “We’ve done this on hundreds and hundreds of wells, and it happens every month without anybody, any manpower, or anything. So that’s one of the huge benefits of doing this in a data-driven manner.” Gas lift is so robust that it can be challenging to diagnose if the system is operating in a suboptimal state, the paper noted. Changes in a well’s water cut or productivity can cause a previously optimized system to lose efficiency, which may not otherwise be known for years. ExxonMobil was seeking a method to optimize gas lift that would continuously monitor the state of the system and respond immediately. The resulting closed-loop software iteratively performs multirate tests, analyzes the results, and remotely implements set-point changes to optimize the wells. “The optimization process is most effective in an iterative form, in which each multirate test produces a model that suggests a given change,” the paper stated. While each model produces its own optimal injection rate, subsequent models may point to the same injection rate, and thus changes are not always made, Burmaster noted. Even if an initially suggested set point is not optimal, it will “push the well in the right direction,” which improves the starting point for the next test and helps the well reach an optimal set point over the course of a few iterations, according to the paper. The workflow was tested in two different stages, with the first 3-month stage requiring manual approval of the recommended set points.

Research on Production Operation System of Sucker Rod Pumping Units

Oil is the most important raw material in modern industry, and its extraction mainly relies on natural flow and artificial lifting. Sucker rod pumping is currently the most widely used method of artificial lifting for mechanical oil extraction, accounting for about 60% to 70% of all methods. This paper deeply explores the theoretical methods involved in the production operation process of sucker rod pumping units. From the perspective of sucker rod pumping unit production operation, a literature review is conducted on the flow patterns in the wellbore, pump efficiency analysis, and intermittent oil extraction systems, clarifying the optimization objectives of liquid production and system efficiency, and sorting out from the aspects of dynamic liquid level, pump efficiency, reasonable submergence depth, and intermittent operation systems. Through in-depth analysis of these key areas, a solid methodological foundation is provided for the future design and development of sucker rod pumping unit production operation systems.

Factors affecting gasless reduced-port laparoscopic myomectomy (GRP-LM) using a subcutaneous abdominal wall lifting method: a retrospective analysis of a large cohort of 966 cases in Japan.

To evaluate the usefulness of gasless reduced-port laparoscopic myomectomy (GRP-LM) using a subcutaneous abdominal wall lifting method. In GRP-LM, after lifting the abdominal wall by a subcutaneous abdominal wall lifting method, a 1.5-cm incision is made in the lateral abdomen, Lap Protector® is placed. The operation is performed by two surgeons, one who inserts multiple forceps from the Lap Protector and performs the operation, and an assistant who operates the laparoscope and uterine manipulator. The surgical outcome of GRP-LM and the factors that affect it were investigated. GRP-LM was performed in 966 patients. Complications (0.5%) and blood transfusions (0.3%) were remarkably rare, and there were no cases of conversion to open surgery. With regard to the correlation between the number of fibroids extracted and each factor, the number of fibroids extracted correlated with fibroid weight and operation time, but not with blood loss. The average number of sutures per case was 21, and the average suture and ligation time per suture was 77s. Comparing the cost of GRP-LM with that of the conventional insufflation LM, a saving of $875 was possible with GRP-LM. GRP-LM is a suitable for multiple fibroids, and is cosmetic and economical, because it allows rapid and reliable suture and ligation, despite having only one port for the procedure.

Efficient analysis and evaluation method for overall lifting of large-span spatial grid structures

Large-span spatial grid structures are commonly employed on the roofs of various public buildings and are typically installed via an overall lifting method. However, the process of overall lifting cannot ensure complete synchronization, which may result in damage to the structure or the lifting equipment. It is imperative to ascertain the limit state of the structure under asynchronous conditions and to develop an accurate model for rapidly assessing the critical response during the lifting process. This paper introduces an efficient approach for evaluating and analyzing the overall lifting process of large-span spatial grid structures. The iterative limit boundary (ILB) method is proposed in this paper, which facilitates the rapid determination of the limit boundary and the limit state for a structure-equipment system with asynchronous lifting. Furthermore, the genetic algorithm is integrated into the ILB method to enhance its efficiency when dealing with numerous lifting points. An agent model capable of outputting key structural responses is developed for the rapid evaluation of those responses throughout the lifting process. Both a numerical example and an engineering example are provided to validate the proposed method. The computational results indicate that the method proposed achieves accurate results with a computational cost merely 3 % of that of the Monte Carlo simulation. Additionally, the agent model established within the limit boundary, operates at a speed 200 times faster than finite element analysis, thereby enabling precise and real-time critical response assessments.

Digital twin method for intelligent lifting of cable structures under multi-collaborative mode

In order to ensure the high efficiency and quality consistency of cable structure in each construction stage, this study proposes a digital twin method for intelligent lifting of cable structure under multi-collaborative mode. Firstly, a construction and operation methods of the digital twin logic model are formed. In the logical model, a relationship between the transmission and iteration of construction information in the collaborative process is defined. In order to realize the adaptability of working conditions, the coupling relationship between construction step and structural elevation is established. A cable structure lifting analysis model driven by an improved long short-term memory neural network is proposed, which effectively solves the problem of poor convergence of the traditional finite element method. An automatic time window selection method is formed for the neural network. An adaptive moment estimation method is used for neural network parameter optimization, which improves the efficiency and accuracy of the analysis. Taking the lifting process of a cable truss structure test model as an example, a digital twin collaborative construction platform is established to verify the effectiveness and feasibility of the research method. The results show that the digital twin logic model realizes the process collaboration, scene collaboration and data collaboration, and significantly improves the stability of construction quality and the linkage of construction process. Through the improved long short-term memory neural network, the coupling relationship between the construction step and the structural elevation is established, which accurately guides the whole construction process.

Evaluation and selection of the best artificial lift method for optimal production using PIPESIM software

A well can be produced and exploited when it has production power, in other words, if the well does not have enough pressure, it will not be able to flow. Artificial production is a method to increase the lifespan of well production. The well studied in this article has a significant annual lower pressure drop; So now with the current pressure of the existing well, it is not possible to send the oil of this well to the separator of the first stage of the exploitation unit. Among the existing solutions to maintain or increase production and increase the flow pressure of the well, is the use of artificial extraction. In this article, an attempt has been made to simulate the effect of using a core pipe, gas pumping and installing an electric submersible pump (ESP) on the production flow rate and flow pressure of the well by using the well data and the static and current pressure test. The current production data with the PIPESIM software was checked, and then the best extraction method for the studied well. Finally, the installation of an ESP was determined and selected as the best method of artificial extraction.

Design Evaluation Of Hydraulic Pumping Unit At Well Alf-04 Kawengan Field

The methods of lifting fluid from the well to the surface consists of natural wells method and artificial lift method. One type of artificial lifting is Hydraulic Pumping Unit (HPU) method. In this case, well ALF-04 as the HPU well in Kawengan field which faces lower actual production compare to its theoritic production calculation then decided need to be redesigned. The objectives of redesigned is to reach optimum flow rate of the well. Recently actual flow rate of this well is 309.2 bfpd, and then the result of IPR calculation by Vogel shows the Q max is 957.25 bfpd, it means this well production is still feasible to be optimized till approximately 765.8 bfpd. After redesign calculation , obtained pump setting depth 755 m, plunger size of 2.5 ", 120" stroke length, and speed of 6 spm, pump displacement 568.425 bpd. For the rod diameter was changing from 0.75 inch to 0.875 inch with total length 2395m , it greatly affects the maximum stress value of 22,774.03 psi, and also has an influence to the increasing of PPRL value of 8243.26 lb, and the MPRL value of 3000 lb.

Anatomical perspectives of brow-lifting using threads: Clinical cases with techniques.

Tailoring surgical interventions to target age-related transformations is paramount. Many candidates seeking blepharoplasty commonly exhibit eyebrow ptosis, underscoring the necessity for surgeons to possess a comprehensive understanding of techniques for brow and forehead rejuvenation. Various surgical techniques are available for eyebrow and forehead enhancement, contrasting the standardized approaches in upper and lower blepharoplasty. Thread lifting has gained popularity for forehead lifting, although a more precise term would be eyebrow lifting. The thread lifting methods using V and I techniques with floating-type threads (Secret Line, Hyundai Meditech., Inc., Wonju-si, Republic of Korea) are used. The natural aging process often causes the forehead and eyebrows to sag under the influence of gravity, leading to the appearance of heavy eyelids. Elevating the eyebrows can mitigate droopiness, enhance vision clarity, and rejuvenate the facial aesthetic. While non-surgical methods like Botulinum Toxin A can weaken muscles and potentially aid in brow elevation, their visible effects may be somewhat constrained. Surgical methods encompass endoscopic forehead lift, eyebrow lift techniques, and scalp excision-based forehead reduction surgery, each with specific advantages and drawbacks. Thread lifting bridges the gap between surgical and non-surgical modalities. Forehead areas often lack subcutaneous fat, requiring precise anatomical understanding for effective thread lifting. Cannula usage with partial tunneling ensures efficacy even in patients with strong adhesions. Presented cases showcase successful eyebrow lifting using cog threads, illustrating immediate and gradual post-procedure changes. Eyebrow thread lifting demands periodic procedures, offering subtler improvements than surgery. Anatomical knowledge is crucial, and the technique presents discomfort. Effects last about 6 months, requiring re-treatment as effects regress. Thread lifting, a middle ground between surgical and non-surgical methods, can rejuvenate brows with less downtime.

Increasing productivity by using smart gas for optimal management of the gas lift process in a cluster of wells

In the face of the escalating global energy demand, the challenge lies in enhancing the extraction of oil from low-pressure underground reservoirs. The conventional artificial gas lift method is constrained by the limited availability of high-pressure gas for injection, which is essential for reducing hydrostatic bottom hole pressure and facilitating fluid transfer to the surface. This study proposes a novel ‘smart gas’ concept, which involves injecting a gas mixture with an optimized fraction of CO2 and N2 into each well. The research introduces a dual optimization strategy that not only determines the optimal gas composition but also allocates the limited available gas among wells to achieve multiple objectives. An extensive optimization process was conducted to identify the optimal gas injection rate for each well, considering the limited gas supply. The study examined the impact of reducing available gas from 20 to 10 MMSCFD and the implications of water production restrictions on oil recovery. The introduction of smart gas resulted in a 3.1% increase in overall oil production compared to using natural gas. The optimization of smart gas allocation proved effective in mitigating the decline in oil production, with a 25% reduction in gas supply leading to only a 10% decrease in oil output, and a 33% reduction resulting in a 26.8% decrease. The study demonstrates that the smart gas approach can significantly enhance oil production efficiency in low-pressure reservoirs, even with a substantial reduction in gas supply. It also shows that imposing water production limits has a minimal impact on oil production, highlighting the potential of smart gas in achieving environmentally sustainable oil extraction. Furthermore, the implementation of the smart gas approach aligns with global environmental goals by potentially reducing greenhouse gas emissions, thereby contributing to the broader objective of environmental sustainability in the energy sector.

The Endo-lift Laser (Intralesional 1470 nm Diode Laser) for Dermatological Aesthetic Conditions: A Systematic Review.

The prominence of minimally invasive aesthetic approaches has become increasingly pivotal. The endo-lift laser method is an intralesional 1470nm diode laser connected to a fiber that serves both therapeutic and aesthetic properties. We sought to evaluate the efficacy and safety of the endo-lift laser method for dermatological aesthetic applications. PubMed, Ovid-Embase, and Web of Science were systematically searched up to November 5th, 2023. A citation search was also performed. The National Institute of Health (NIH) Quality Assessment Tool was used to evaluate the quality of the studies. Out of 339 articles, twenty-three relevant studies were included in the current review. Applying the endo-lift laser method for rejuvenation, including face and neck lifting, enhancing skin laxity, and disappearing wrinkles, folds, and lines, demonstrated favorable efficacy and safety profile. Moreover, most studies have shown that the endo-lift laser method is promising in eliminating the adipose tissue in the jowl, abdomen, thighs, and arms. The endo-lift laser technique was also efficacious in nose remodeling and blepharoplastic procedures, including treating eyelid and eyebrow ptosis, eye bag, eyebrow position, and eyelid laxity. Patients who suffer from several diseases, such as hidradenitis suppurativa, progressive lipodystrophy, acne vulgaris, scars, and keloids, benefit from procedural treatment with the endo-lift laser technique. Across all studies, the adverse events were mild and self-limiting. Investigating the endo-lift laser method in all aesthetic and therapeutic indications resulted in high patient satisfaction rates. The endo-lift laser technique has therapeutic effects and is recommended for various dermatological aesthetic indications. Further clinical studies with control groups and larger sample sizes are needed to acquire more reliable evidence. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

ESP vibration prediction based on pump operating conditions in laboratory using machine learning

Electric Submersible Pump (ESP) is an effective artificial lift method of pumping medium to high production fluids. However, it is prone to failure because most of the system is located downhole. When mechanical defects start to develop, vibration signal changes. By examining the variation in vibration, component failures can be located and predicted. The objective of this study is to creates a machine learning model to predict ESP vibration using experimental data. The dataset that was utilized to create the model has more than a million data points collected from laboratory. Based on pump performance, the experimental data are divided into three groups: normal, advised and failing pump conditions. The model features are operating time, pump speed, oil flow rate, water flow rate, pump intake pressure, motor temperature, free gas percentage and liquid/mixture density and viscosity. Among the algorithms used to develop the model, random forests regression produces results with acceptable accuracy while not requiring too much computing power. Because of that, random forests regression was used for further optimization and simulation. The results of the model show that pump speed and operating time have the biggest effects of all the features. Due to the limited range of experimental data, in some cases, it is either unknown or unclear how the features affect ESP vibration, particularly in advised and failing pump conditions. The model's vibration predictions closely match the results of the experiments. This model can be used to forecast pump vibration under a particular operating condition by incorporating into the ESPSim program. The predicted vibration magnitude can be compared to the actual value to determine whether an ESP is in failing condition. With this information, the amount of downtime when the pump fails could be minimized. The extreme downhole conditions can also cause sensor cables to break and become incapable of transmitting data to the surface. Operators can use predicted ESP vibration to get an idea of the status of the pump.

Aero-propulsion analysis of distributed ducted-fan propulsion based on lifting-line driven body-force model

As the environmental problems become increasingly serious, distributed electrical propulsion systems with higher aerodynamic efficiency and lower pollution emission have received extensive attention in recent years. The distributed electrical propulsion usually employs the new aero-propulsion integrated configuration. A simulation strategy for internal and external flow coupling based on the combination of lifting line theory and body force method is proposed. The lifting line theory and body force method as source term are embedded into the Navier-Stokes formulation. The lift and drag characteristics of the aero-propulsion coupling configuration are simulated. The results indicate that the coupling configuration has the most obvious lift augmentation at 12° angle of attack, which can provide an 11.11% increase in lift for the airfoil. At 0° angle of attack, the pressure difference on the lip parts provides the thrust component, which results in a lower drag coefficient. Additionally, the failure impact of a ducted fan at the middle or edge on aerodynamics is investigated. For the two failure conditions, the lift of the coupling configuration is decreased significantly by 27.85% and 26.14% respectively, and the lip thrust is decreased by 70.74% and 56.48% respectively.

Evaluation of the microbial wet-vacuum system (M-Vac®) for DNA sampling from rough, porous substrates, and its compatibility with fully automated platforms

DNA retrieval methods traditionally used during forensic evidence recovery including swabbing and tape lifting, can have limited effectiveness when used on porous, rough substrates such as bricks and carpet. This is possibly due to the DNA material being dispersed and unreachable for surface sampling techniques. In this evaluation we investigated the effectiveness of the Microbial Wet-Vacuum System (M-Vac®; M-Vac® Systems, Inc., Sandy, UT), as it has been reported to retrieve greater amounts of DNA material from challenging exhibits. A four-stage evaluation was conducted, starting with seeding carpet and brick substrates with a known donor’s saliva in two dilutions and comparing the DNA recovery of tape lifting, swabbing, and the M-Vac®. A victim struggle scenario on carpet was then mimicked to compare trace DNA recovery by each method. Two mock scenarios were also conducted; a shirt was submerged in a creek bed for a period of five days to sample for the wearer’s DNA, and a car boot was sampled to assess the possibility of recovering a victim’s DNA amongst background DNA from the usual car occupants. Finally, the compatibility of the M-Vac® sampling process was optimised for the fully automated DNA lysis and extraction platforms used in the NSW (Australia) jurisdiction by comparing filter subsampling methods. The results from the study were mixed. For bricks, none of the collection methods were effective in retrieving DNA. On carpet, the M-Vac® retrieved the greatest quantities of DNA from the saliva-seeded samples, however, tape lifts outperformed all methods for ‘touch’ DNA recovery. The M-Vac® retrieved the greatest amount of DNA from the t-shirt recovered from a creek bed as it was able to retrieve the embedded DNA. The final mock case car boot scenario resulted in greater victim DNA recovery from tape lifts, with the M-Vac® more likely to recover mixtures too weak and/or complex to be interpreted. Finally, operational considerations regarding the compatibility of the M-Vac® system with fully automated DNA lysis and extraction are discussed. Considering the substantial time and cost to deploy the M-Vac®, it is recommended to be utilised in casework only after swabbing and tape lifting methods have failed to yield sufficient DNA material, where the substrate properties would likely benefit from the M-Vac’s® niche capabilities for retrieving embedded DNA, and low levels of background DNA may be anticipated.

A novel sparse-based approach for joint radio frequency fingerprint and channel estimation

Radio Frequency Fingerprint (RFF) plays a pivotal role in specific emitter identification (SEI) and enhancing the physical layer security of wireless networks. However, past research on RFF extraction has encountered significant challenges, including algorithm instability in the presence of multi-path channels, disparities between actual RFF and proposed models, and the need to compensate for receiver RFF. In this study, we introduce an innovative algorithm designed to simultaneously estimate the transmitter's RFF and the non-line-of-sight (NLOS) channel state in the presence of receivers’ antenna effect. Moreover, we introduce the transmitter antenna feeding current as a modified RFF, accounting for transimtter components such as power amplifier (PA) nonlinearity, in-phase quadrature (IQ) modulator imbalance. Our approach commences with an exploration of wave propagation theory fundamentals, followed by a transformation of the inverse scattering equations into linear equations for joint channel and RFF estimation. Due to the non-convex nature of the derived equation, we employ the sparse lift method to render the problem convex. Leveraging the sparsity of channel coefficients, we devise a compressive sensing linear solution, denoted as the sparse-based approach for joint (SBJ) RFF and channel estimator. Additionally, we propose a calibration method to mitigate the effect of the receiver antennas on the estimated RFF of the transmitter. Through simulation, we demonstrate a 10 dB enhancement in RFF estimation accuracy compared to existing methods. Furthermore, our results indicate that the SBJ algorithm remains robust when faced with the combined effect of transmitter components, whereas previous models exhibit diminished precision as additional component effects are considered.

Virtual parameter calibration of pod pepper seeds based on discrete element simulation

In order to achieve numerical optimization of the pod pepper seed sowing device, the contact parameters of pod pepper seeds were calibrated, with the angle of repose used as the response value. A set of discrete element method (DEM) models of pod pepper seeds was developed to simulate the formation of seed repose angles using reverse engineering reconstruction techniques. An eight-factor, three-level response surface experiment based on the Box-Behnken central combination test method was performed to study the effects of various factors on the angle of repose of seeds. The angle of repose obtained from physical experiments with a value of 27.56° was taken as the target value. The optimal combination of parameters is obtained as follows: seed Poisson's ratio of 0.22, seed shear modulus of 15.47 MPa, seed-to-seed static friction coefficient of 0.25, seed-to-seed rolling friction coefficient of 0.67, seed-to-seed collision recovery coefficient of 0.64, seed-to-steel-plate static friction coefficient of 0.55, seed-to-steel-plate rolling friction coefficient of 0.45, and seed-to-steel plate collision recovery coefficient of 0.34. A two-sample t-test of the angle of repose obtained by the cylinder lifting method and the pumping plate method against the target value yielded P > 0.05, indicating the reliability of the simulation experiments.

SUMMABILITY AND ASYMPTOTICS OF POSITIVE SOLUTIONS OF AN EQUATION OF WOLFF TYPE

SUMMABILITY AND ASYMPTOTICS OF POSITIVE SOLUTIONS OF AN EQUATION OF WOLFF TYPE

Design and application of small-diameter closed thoracic drainage tube fixation following lung wedge resection: A randomised prospective study.

The use of indwelling closed thoracic drainage tubes in the wedge resection of the lungs is of great significance to postoperative recovery. However, there are potential risks. To explore the design feasibility and application effect of triple-buffer-system-fixed small-diameter (18 F) thoracic closed drainage tubes following lung wedge resection. A total of 136 patients with indwelling thoracic drainage tubes following pulmonary wedge resection were recruited, with 70 patients allocated to the control group and 66 to the experimental group. The drainage tube in the experimental group was fixed with the triple-buffer system, while that in the control group was fixed using the conventional lifting platform method. The incidence of unplanned extubation, the indwelling time of the drainage tube and the time and material costs, as well as information regarding any subcutaneous emphysema and skin tension blisters, were recorded following the operation. The pain and degree of comfort were assessed using a chi-square test and a rank sum t-test to compare the differences between the two groups. There were no statistically significant differences in terms of age, gender and sweating between the two groups. Compared with the control group, the unplanned extubation rate of the experimental group was lower (χ2= 8.513; P= 0.004), the indwelling time of the drainage tube was shorter (t= 2.108; P= 0.037), the cumulative material cost was lower (t= 3.778; P< 0.001), the time cost was also lower (Z= 2.717; P= 0.008), the degree of comfort was higher (Z= 2.752; P= 0.006), and the degree of pain was lower (Z= 4.019; P< 0.001). The incidence of subcutaneous emphysema was significantly lower in the experimental group than in the control group (χ2= 8.513; P= 0.004). The use of the triple-buffer system to fix small-diameter (18 F) thoracic closed drainage tubes can reduce the unplanned extubation rate, indwelling time of the drainage tube and the incidence of adverse reactions.