Angle Method Research Articles

Development of a novel sensor based on Bi2O3 and carbonized UIO-66-NH2 nanocomposite for efficient detection of Pb(Ⅱ) ion in water environment

Development of an efficient monitoring technology for rapid detection of toxic Pb(Ⅱ) ion in water environments is extremely important. Here, a novel and highly sensitive sensor was prepared using one-step calcination technique, based on Bi2O3 nanoparticles and carbonized metal–organic framework (MOF) nanocomposite. Scanning electron microscopy, transmission electron microscopy, contact angle and X-ray photoelectron spectroscopy characterization methods were used to analyze the morphology and structure of the prepared materials. Based on the electrical double-layer capacitance theory and Raman spectroscopy, changes to the active sites of different modified materials were investigated. Besides, differential charge densities and adsorption energies of the different modified materials in Zr-O clusters were calculated using density functional theory (DFT). A Bi2O3 and carbonized UIO-66-NH2 (Bi2O3/C-UIO-66-NH2) -modified glassy carbon electrode was used to detect Pb(Ⅱ) by differential pulse anodic stripping voltammetry. Under optimal experimental parameters, the developed electrochemical sensor has a wide linear range (2–130 μg/L) and a low detection limit (0.05 μg/L). Meanwhile, the sensor has excellent stability, repeatability, and anti-interference properties and has been successfully applied to detect Pb(Ⅱ) in actual water samples. The results of this paper show that our developed sensor an efficient and rapid sensor technology for monitoring lead in water environment.

Magnetic field-induced variation of solid/liquid interfacial energy of solid Al2Cu and Al-Cu eutectic melt

We investigated the effect of static magnetic field (SMF) on interfacial energy of solid Al2Cu and eutectic melt both by dihedral angle and grain boundary groove method. To uncover the effect of SMF on the interfacial energy, its values were determined and calculated based on the morphologies of dihedral angles and grain boundary grooves. A variation of solid/liquid interfacial energy with SMF up to a factor of three was found experimentally. We found that the solid/liquid interfacial energy experienced a declined trend with increasing SMF under both cases. While in grain boundary groove method, the dramatic decrease of solid/liquid interfacial energy with 0.5 T magnetic field was owning to thermoelectric magnetic convection at the scale of sample. At a high intensity (12 T), thermoelectric magnetic convection at the scale of grain boundary groove and thermoelectric magnetic force in solid were supposed to be responsible for the slight increase of solid/liquid interfacial energy. Determined by two methods, the decreased intrinsic solid/liquid interfacial energy was explained with the magnetic dipole theory and structural ordering based on Ewing’s model. We clarified some conflicting and ambiguous experimental phenomena in magnetic field-induced solid/liquid interfacial energy variation. This study provides consolidate evidence that the SMF is capable of affecting the solid/liquid interface energy.

Failure mechanism and stability analysis of an open-pit slope under excavation unloading conditions

Excavation unloading significantly contributes to rock slope failure in an open-pit mine. At present, there is no relevant theoretical study on the failure mechanism of the rock slope under excavation unloading. Therefore, in this study, based on the theory of fracture mechanics, the expression of the stress intensity factor at the crack tip on the rock mass at the vertical distance, h, from the slope top under excavation unloading is derived, the calculation method of the crack initiation angle is given, the expression of the ultimate safe height of the slope under unloading is obtained, and the ratio of the fracture toughness of the slope rock mass to the composite stress intensity factor at the crack tip on the rock mass is defined as the slope stability factor, which is verified by an engineering example. The results show that the crack initiation angle decreased when crack inclination was increased, and the crack initiation angle increased when the side-pressure coefficient, slope angle, and friction coefficient were increased. The ultimate safety height of the slope decreased first and then increased with the increase in the crack angle, and it was approximately linear with the crack length and inversely proportional with the slope angle. The stability coefficient calculated by this method is the same as that calculated by the limit equilibrium method and is small, which indicates the accuracy and rationality of this method. Results in this study can provide a theoretical basis for understanding and controlling the slope collapse disaster induced by excavation unloading.

Analysis of the contact angle of ball screw with Gothic profile considering raceway profile manufacturing error and radial clearance

The ball screw is a mechanical linear actuator that translates rotational motion to linear motion with little friction. The elastic contact angle is considered as the key parameter for the ball screw mechanism with Gothic profile, and it is hard to measure this parameter directly. This paper investigates a calculation method for elastic contact angle of the ball screw considering the raceway profile manufacturing error and radial clearance. The method is based on two deformation model of balls under two preload states in ball screw. The deduced formula from the model on free contact angle is found to be identical with results of split inner-ring ball bearing. The effect of the radial clearance and raceway profile manufacturing error are investigated in this paper. The results show that the radial clearance is a key factor affecting the elastic contact angle. The research provides a theoretical basis for error analysis and optimization design of the new type double-nut ball screw mechanism.

The effect of essential oils mixture on chitosan-based film surface energy and antiadhesion activity against foodborne bacteria.

In the food sector, the formation of biofilms as a result of microbial adherence on food-grade surfaces causes a major problem resulting in significant economic losses. Thereby, this work aimed to elaborate a biodegradable film using chitosan (CS-film) and reinforce its antiadhesion activity by incorporating pelargonium, clove, thyme, and cinnamon essential oils (EOs). Firstly, the antibacterial activity of these EOs alone and combined against four foodborne bacteria were analyzed by the microdilution method. Synergism was observed in the case of EOs combination. Secondly, the physicochemical characteristics and antiadhesion behavior of the CS-films were assessed by the contact angle method and ESEM, respectively. Results revealed that the EOs mixture treatment impacted considerably the physicochemical characteristics of the CS-film and reduced its qualitative and quantitative hydrophobicity. Moreover, the treated CS-film showed a strong antiadhesion behavior against Enterococcus hirae, Pseudomonas aeruginosa, Escherichia coli, and Staphylococcus aureus with percentages of non-covered surface equal to 97.65 ± 1.43%, 98.76 ± 0.32%, 99.68 ± 0.28%, and 95.63 ± 1.32% respectively. From all these results, the CS-film treated with the mixture of EOs presents a great potential for application as surface coating and food packaging preventing microbial adhesion and thus, avoiding food contamination and spoilage.

Transient characteristics of mobile transformer vehicle bypass operation

The bypass operation method of mobile transformer vehicles is a common method for the maintenance or replacement of transformers in distribution lines. Using the bypass operation method could avoid power outages and ensure the reliability of electricity consumption. However, the transient characteristics of mobile transformer vehicles connected to the grid can have an impact on their power quality. In response to this problem, this study built a model based on MATLAB/Simulink to model the process of grid connection. The simulation analyzed the current and voltage waveforms of the transient process of grid connection. Moreover, a combination of time-domain and frequency-domain analysis was used to analyze the transient overvoltage and overcurrent conditions of the grid connection. Finally, the effects of two overcurrent suppression methods, adjustment of the closing angle method and the series closing resistance method, were analyzed. These studies provide theoretical guidance for engineering applications, which could strengthen the stability of the distribution network.

Detection and Recognition Algorithm of Arbitrary-Oriented Oil Replenishment Target in Remote Sensing Image

In view of the fact that the aerial images of UAVs are usually taken from a top-down perspective, there are large changes in spatial resolution and small targets to be detected, and the detection method of natural scenes is not effective in detecting under the arbitrary arrangement of remote sensing image direction, which is difficult to apply to the detection demand scenario of road technology status assessment, this paper proposes a lightweight network architecture algorithm based on MobileNetv3-YOLOv5s (MR-YOLO). First, the MobileNetv3 structure is introduced to replace part of the backbone network of YOLOv5s for feature extraction so as to reduce the network model size and computation and improve the detection speed of the target; meanwhile, the CSPNet cross-stage local network is introduced to ensure the accuracy while reducing the computation. The focal loss function is improved to improve the localization accuracy while increasing the speed of the bounding box regression. Finally, by improving the YOLOv5 target detection network from the prior frame design and the bounding box regression formula, the rotation angle method is added to make it suitable for the detection demand scenario of road technology status assessment. After a large number of algorithm comparisons and data ablation experiments, the feasibility of the algorithm was verified on the Xinjiang Altay highway dataset, and the accuracy of the MR-YOLO algorithm was as high as 91.1%, the average accuracy was as high as 92.4%, and the detection speed reached 96.8 FPS. Compared with YOLOv5s, the p-value and mAP values of the proposed algorithm were effectively improved. It can be seen that the proposed algorithm improves the detection accuracy and detection speed while greatly reducing the number of model parameters and computation.

Estimation method of vehicle sideslip angle considering coupled longitudinal and lateral dynamics

Estimation method of vehicle sideslip angle considering coupled longitudinal and lateral dynamics

Calibration method for high-power and wide-band laser beam divergence angle

在大功率激光系统的评价与分析中，激光器的光束品质是系统光束品质的决定性因素，也是激光器验收、鉴定的重要指标，其中束散角是判别激光光束质量的重要参数。本系统测试激光波长的范围比较宽，一般在0.532 μm~10.6 μm之间，没有合适的探测器能够覆盖整个波段，所以采用了一种新的方法来解决宽波段束散角的测量问题。选用CCD成像和扫描狭缝相结合的方法来实现宽波段激光光束束散角的测量，可见光和近红外波段（0.532 μm~1.2 μm）激光光束采用CCD法测量激光束散角，中红外波段（1.2 μm~10.6 μm）激光光束采用扫描狭缝法测量激光束散角。两种方法的结合可以较为精确地测量出不同波段的激光束散角。

Measurement method of helicopter blade root torsion angle based on perspective transformation

现有方法常将相机从下至上拍摄标记物图像，当桨叶扭转幅度较大时，相机主光轴与标记物平面法向量存在明显夹角，导致拍摄图像存在透视畸变现象，从而引发较大测量误差。为解决上述问题，提出一种基于透视变换的直升机桨根扭转角测量方法。首先，将靶标垂直固定在桨叶下方，相机正对桨毂拍摄图像。其次，计算桨叶在低速拉平状态下待测方位与正方位靶标图像中的四个顶点坐标，并求解待测方位的透视变换矩阵，然后利用透视变换矩阵对桨叶高速运动状态下待测方位拍摄的畸变图像进行校正。最后，求得基准图像与校正后图像中的圆心坐标，进而计算出待测方位扭转角。实验结果表明，各方位测量误差均小于0.2°。该方法不但测量精度高，而且具有多方位动态测量的优点，在直升机旋翼桨叶运动参数测量领域具有良好的应用前景。

The effectiveness of Schroth method in Cobb angle, quality of life and trunk rotation angle in adolescent idiopathic scoliosis: a systematic review and meta-analysis.

The Schroth method is one of the most common physiotherapeutic scoliosis-specific exercises intervention applied in adolescent idiopathic scoliosis (AIS). This method consists of three-dimensional correction of the specific curve pattern of the patient using a combination of sensorimotor, postural, and corrective breathing exercises. The aim of this systematic review and meta-analysis was to analyse the effects of the Schroth method in isolation on Cobb angle, quality of life, and trunk rotation angle compared to no intervention or other conservative treatments in patients with AIS. PubMed, Physiotherapy Evidence Database, Scopus, Cochrane Library, and Web of Science databases were searched. Studies were included if they were randomized controlled trials that compared the effects of the Schroth method in isolation to conservative interventions or no intervention. The quality of the studies was assessed with the PEDro Scale, and the risk of bias with the Cochrane Collaboration tool. Two independent assessors extracted data through a standardized form. Meta-analyses were conducted using fixed or random effects models according to the heterogeneity assessed with I2 coefficient. Data on outcomes of interest were extracted by a researcher using RevMan 5.4 software. A total of 317 studies were screened. Six were included in the meta-analysis involving 144 patients with AIS. The methodological quality of the included studies ranged from high to low. Schroth method in isolation showed significant improvements in Cobb angle (mean difference [MD] =-3.18º; 95% CI: -4.30, -2.07; I2: 0%), quality of life (MD=0.28; 95% CI: 0.18, 0.38; I2: 0%) and trunk rotation angle (MD=-2.12º; 95% CI: -3.44, -0.80; I2: 71%) in the short-term. The Schroth method in isolation is effective for reducing the Cobb angle and the trunk rotation angle and for improving the QoL in the short-term compared to no intervention or other conservative therapies in AIS, but the improvement in Cobb angle did not exceed the minimum clinically important difference.

Estimation method of vehicle sideslip angle considering coupled longitudinal and lateral dynamics

Estimation method of vehicle sideslip angle considering coupled longitudinal and lateral dynamics

Study of quantum speed limit of of transport process of single quantum dot system in dissipative environment

We theoretically study the quantum speed limit (QSL) of the single dot system in dissipative environment based on quantum dot transport theory and Bures angle metric method. The theoretical results show that in the dissipative environment, different tunneling probabilities have different effects. The increase of left tunneling probability has a weak effect on the accelerating capability of the system, due to the Coulomb blocking effect and quantum coherence. On the other hand, the right tunneling probability has a significant influence on the accelerating capability of the system, the accelerating capability is promoted with the increase of right tunneling probability because of the effect of channel blocking and co-tunneling. The increase of energy displacement promotes the accelerating capability of the system and changes the oscillation frequency of the system, owing to its taking longer time for the system to evolve to a target state. The effect of the relaxation rate for the system's accelerating capability is not monotonic, there is an interesting turning point due to the change of electron layout number. When the relaxation rate is less than this point, the accelerating capability of the system will oscillate. When the relaxation rate is higher than this point, the change of accelerating capability is monotonically suppressed by the relaxation rate. In general, the increase of the relaxation rate weakens the acceleration capability of the system. Our results provide theoretical reference for studying the QSL time in a semiconductor device affected by numerous factors.

Methods for forming of profile pipes from round billet

Shaped tubes production tendencies and the methods of their manufacturing are considered. An analysis of rollforming methods from a round billet is carried out. Approaches to the various rollforming design methods from a round billet are outlined. An angle modification method is proposed as the most probable in the production of shaped tubes from a round billet.

A HYBRID SOLVER FOR THE RADIATIVE TRANSFER EQUATION IN NONGRAY COMBUSTION GASES

The discrete ordinates method (DOM) or its variant, the finite angle method (FAM), is a popular solution method for the radiative transfer equation (RTE). Accurate solution to the RTE using the DOM or FAM requires many solid angles (directions) in multidimensional geometry. In combustion gases, where the absorption coefficient oscillates wildly and the RTE must be solved repeatedly, this method becomes computationally intractable. Here, the FAM is hybridized with the P<sub>1</sub> approximation, which is efficient since it requires solution to a single partial differential equation as opposed to a set of directional RTEs in the FAM. The P<sub>1</sub> approximation is accurate when the intensity field is fairly isotropic, as evidenced in optically thick media. Hence, the hybridization employs the FAM for optically thin and intermediate spectral intervals and employs the P<sub>1</sub> approximation for optically thick spectral intervals. The objective of the present study is to determine optimal parameters for hybridization that can provide the best compromise between accuracy and efficiency. Using a narrowband-based box model for carbon dioxide and water vapor, the nongray radiative transfer equation is solved in media with nonuniform properties enclosed in multidimensional enclosures. Two different approaches-cutoff and filter optical thickness-are investigated for hybridizing. Several problems, both two- and three-dimensional, and with and without coupling to other modes of heat transfer are considered. The filter approach was found to be the best choice for prediction of the radiative source and temperature (in the case of a coupled mode), while the cutoff approach was found to be the best for prediction of wall radiative heat fluxes.

Immediate effect of sciatic nerve sliders on hamstring length and lumbar flexion range of motion in sedentary desk job workers: An interventional study

BACKGROUND: In sedentary desk job workers, who assume the sitting position for a long time, there is a chance of the neural tissue tightness which could lead to reduced range of motion at the various joints of the body, to develop over a period of time. AIMS AND OBJECTIVE: The study aimed to compare the change in hamstring muscle length and lumbar flexion range, after the sciatic nerve slider intervention. METHODS: It is an interventional study including 156 participants who were working as sedentary desk job workers in the age group of 20 to 50 years with mild to moderate hamstring tightness. After taking the written informed consent of the participants, their demographics were noted, following which the hamstring muscle length was assessed by popliteal angle method using a goniometer and the lumbar flexion range was assessed by modified Schobers. RESULTS: There was a statistically significant difference in hamstring length (P = 0.000) and lumbar flexion range (P = 0.000) post the sciatic nerve slider intervention among the participants. CONCLUSION: The two ended proximal and distal sciatic nerve sliders had a significant impact on increasing the hamstring length and lumbar flexion range on sedentary desk job worker.

Method of the Protected Volume LPZ0B of Lightning Air-Termination Systems

The protection system for the structures against lightning is basically constituted by means of an air termination system, down-conductors and a ground-termination system. The IEC standard 62305 introduces the rolling sphere method to analyze and to design the protected volumes of air-termination systems with a complex configuration. In order to avoid the exposure of equipment and elements on the building roof to direct lightning in the design and the following operation with new exigencies, the identification of the protected volumes LPZ0B allows taking corrective measures if needed. The suggested method assumes as reference element a pair of rods for the air termination system and proposes to identify the protected volume combining the two IEC methods of the graphical rolling sphere with the protective angle. The protected volume method proposes, as simpler first step, the mathematical calculation of the minimum protection height of prospected profile described by the rolling sphere, useful for a preliminary evaluation. As second step, the method completes the definition of the protected volume section, describing a cautionary model that replaces the circular sector of the rolling sphere with a “vase section” shape, applying the protective angle method.

Furanic Polymerization Causes the Change, Conservation and Recovery of Thermally-Treated Wood Hydrophobicity before and after Moist Conditions Exposure.

The Whilhelmy method of contact angle, wood thermal properties (TG/DTG), infrared spectroscopy, etc. was used to define the hydrophobicity of heat-treated beech and fir wood at increasing temperatures between 120 °C and 300 °C. By exposure to wet conditions during 1 week, the hydrophobic character obtained by the heat treatment remains constant heat-treated. Heat induced wood hydrophobation, was shown by CP MAS 13C NMR and MALDI ToF mass spectrometry to be mainly caused by furanic moieties produced from heat-induced hemicelluloses degradation. This is caused by the acid environment generated by the hydrolysis of the hemicelluloses acetyl groups. Furfural polymerizes to linear and branched oligomers and finally to water repellent, insoluble furanic resins. The water repellent, black colored, cross-linked polymerized furanic network is present throughout the heat-treated wood. Wood darkening as well as its water repellency due to increasing proportions of black colored furanic resins increase as a function of the increase with treating temperature, becoming particularly evident in the 200 to 300 °C treating temperature range.

Sagittal Plane Assessment in Deformity Correction Planning: The Sagittal Joint Line Angle.

Evaluate the validity of a recent approach to calculate the knee flexion or extension contracture contributing to the overall sagittal deformity using the sagittal mechanical axis angle (SMAA) for the overall alignment assessment and sagittal joint line angle (SJLA) for soft tissue contribution. The methods of evaluating these angles and their clinical applications are discussed. In total, 107 normal limbs met the criteria and were divided into two groups: skeletally mature and immature. Sagittal alignment was evaluated using the Bone Ninja iPad application, and the posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA), SMAA and SJLA were recorded. In skeletally immature patients, mean SJLA was 13.46° [standard deviation (SD), 4.55°], and in mature patients, it was 16.91° (SD, 2.948°). The PDFA and PPTA were consistent with previously published measurements. The SJLA method is a practical way to quantify the soft tissue contribution and degree of contracture. It can also be used for monitoring deterioration or improvement of knee range of motion during lengthening or physical therapy. All patients in this study presented to our clinic with symptoms on the contralateral side. This, in addition to the retrospective nature, was a limitation in our study.We recommend a validity study to compare our SJLA method to the classic anterior cortical line angle (ACL) method in addition to an inter-observer and intra-observer reliability study for the SJLA. We also recommend a study on completely normal asymptomatic subjects to better standardise the angle measurements in skeletally immature patients at different ages. Abalkhail TB, McClure PK. Sagittal Plane Assessment in Deformity Correction Planning: The Sagittal Joint Line Angle. Strategies Trauma Limb Reconstr 2022;17(3):159-164.

A Novel Methodology to Enhance the Smooth Running of the PM BLDC Motor Drive Using PWM-PWM Logic and Advance Angle Method

This paper addresses the active torque ripple compensation of a permanent magnet brushless direct-current motor (PMBLDC) drive with a new pulse width modulation (PWM) technique and advance angle method. Torque ripple is a well-known problem in BLDC motors which is produced by a discrepancy between the stator current and the back electromotive force (back-emf) waveforms. The advanced angle method proposed in this paper generates a maximum torque in the PM BLDC motor by decreasing the displacement between the phase voltage and phase current in proportion to the load. Further, a simple and comprehensive PWM-PWM logic is proposed in this paper to reduce the torque ripples. The test results show that the BLDC motor drive achieves good steady-state performance while maintaining a quick dynamic response. The performance of the PWM-PWM logic and advance angle method, have been tested and compared with the practical results for the characteristics of DC bus voltage, DC bus current, electromagnetic torque, shaft torque, mechanical torque, phase voltage, phase current and PWM signal.