Installation Position Research Articles

Design of LPG Leakage Detection Device using MQ-2 Sensor Equipped with Hazard Warning System

The use of liquefied petroleum gas (LPG) as household fuel in Indonesia has increased because it has greater heating power and equipment efficiency than other fuels. LPG is flammable and can explode if a leakage occurs and is exposed to a fire source. Therefore, explosions can be anticipated by installing a gas leakage detector equipped with a danger warning feature called Tor-G (LPG Detector) based on the NodeMCU ESP8266 microcontroller using an MQ-2 sensor with a buzzer and LED as a danger warning feature. Tor-G can detect when a gas leakage occurs and provides a danger signal in the form of a sound from a buzzer which can be heard several meters away by the homeowner so that an explosion can be anticipated quickly. This research carried out four tests: the sensor accuracy test, the sensor responsiveness test, the distance between the sensor and the leakage source test, and the responsiveness of the buzzer and LED test. The results of the tests show that the sensor only detects the LPG. The sensor readings are accurate since the value of Rs/Ro on the Tor-G is not much different from that of Rs/Ro on the datasheet, thus producing an error value in the 0% -0.08% range. The ideal installation position of the Tor-G is 75 cm from the gas cylinder and the danger warning system from the buzzer and red LED lights up within 18.88 seconds.

The influence of the guide vane positioning on the flow field of a turbo air classifier

AbstractAs the important component to guide the airflow in the classifier, installation position of the guide vane determines the width of the classification annular region and influences the flow field distribution. The influence of the guide vane positioning on the flow field in the annular region is analyzed through numerical simulation. The simulation results show the tangential velocities near the inner edge of the guide vanes increase, and the tangential velocity gradient decreases with decrease of the width of the annular region. The increases of turbulent dissipation rate near the guide vanes are beneficial to powder dispersion. However, the increases of turbulent dissipation rate near the rotor cage aren′t conducive to uniformity of the flow field. In case of the narrow annular region, the cut size gradually increases when the width of the annular region increases. However, when the width of the annular region continues to increase, the particle′s residence time become long, and the solid concentration increases significantly to increase the probability of particle aggregation. The reasonable range of the installation diameter of the guide vane in the classifier is between 504 mm and 524 mm.

Study on the mooring systems attaching clump weights and heavy chains for improving the typhoon resistance of floating offshore wind turbines

The southeastern coastal region of China is the most favorable area for offshore wind resources in the country, but typhoon impacts constrain the development of floating wind turbines in this region. Therefore, ensuring reliable and efficient mooring performance is crucial due to significant safety concerns presented by dynamic platform motions and mooring line tensions encountered during typhoon conditions. In this study, two mooring models were proposed to investigate the impact of clump weights or heavy chains on enhancing the typhoon resistance of floating offshore wind turbines. The 10-MW OO-Star semi-submersible platform was used as the reference structure. The aero-hydro-servo-elastic coupled simulations using OpenFAST were conducted for the selected environmental condition. The surge motion and fairlead tension were compared in both time-domain and frequency-domain for different mooring configurations. The results demonstrate that adding clump weights and heavy chains effectively limits the surge motion and tension fluctuations. Additionally, five installation positions were proposed and compared. Furthermore, a comparison between clump weights with heavy chains was conducted. The performance of a mooring system can be improved in the typhoon condition by incorporating optimal clump weights or heavy chains.

Analisis Pengelolaan Obat Di Instalasi Farmasi Puskesmas X Kabupaten Sukoharjo

The management of medicines in community health centers is a key element in healthcare services. This study aims to analyze the management of medicines at the Pharmacy Installation of X Community Health Center in Sukoharjo Regency. The aim of this research is to determine the suitability of indicators for the selection, planning, procurement, distribution, and use of drugs at this community health center, and to identify the strategic position of the pharmacy installation within the SWOT matrix. This research employs a descriptive analysis study design with a nonexperimental qualitative approach. Data were collected retrospectively through a review of documented records. Data collection techniques included document review, observation, and interviews at X Community Health Center in Sukoharjo Regency. The results showed that the indicators for compliance with the community health center's formulary were in accordance with standards, but the compliance of medicine items with the national formulary and the national essential medicines list was not up to standard. In the planning and procurement stages, all indicators met standards, such as the comparison between the number of medicine items planned and those actually used, the frequency of procurement of each medicine item annually, and planning deviations. In the distribution stage, the indicators for medicine matching with stock cards and the warehouse management system met standards. In the usage stage, the percentage of prescriptions with generic medicines met standards. The SWOT analysis results indicated a position in quadrant 1.

Research on a self-powered rolling bearing fault diagnosis method with a piezoelectric generator for self-sensing

The self-powered fault diagnosis methods provide a new idea to realize fault diagnosis without using wired sensors or battery-supported sensors. However, current self-powered fault diagnosis methods mainly depend on self-powered sensors, most of which may destroy the original structure of mechanical parts or contain connected energy harvesters and sensors, resulting in reduced reliability and stability. In this paper, a self-powered rolling bearing fault diagnosis method with a piezoelectric generator (PEG) for self-sensing is proposed. The PEG can be simply installed without destroying the bearing structure, and its electrical outputs excited by the mechanical vibrations can be further used for fault diagnosis. The energy conversion mechanism of a conventional monostable PEG and the basic knowledge of the convolutional neural network (CNN) model are first introduced, based on which the self-powered fault diagnosis approach is proposed. Experimental work is conducted to identify the parameters of the PEG's governing equation and verify its effectiveness. The responses of a PEG installed onto a rolling bearing experimental table are further measured and analyzed. Finally, the CNN model is trained based on the electrical outputs of the PEG under different installation positions, different rotation speeds and different healthy statuses of the bearings. The research results show that the average classification accuracies of this method for rotational speeds of 1200 rpm, 3000 rpm and 4800 rpm can achieve 88.389%, 98.99% and 98.431%, respectively, which are quite feasible in practical applications. This work shows a totally new idea of adopting a vibration energy harvester as a self-sensing device to achieve self-powered fault diagnosis, which has wide application potential in the future.

Nighttime measurement errors in the runway visual range and optimization of runway lighting systems

Considering that existing theories consider runway lights as markers, neglecting their roles as lighting devices that increase sky background luminance and thus affect runway visual range (RVR) measurements, the actual values of sky background luminance observed by pilots during take-off are calculated and compared with the instrumental RVR measurements in this paper. The RVR measurement errors due to the installation positions of these devices are subsequently analysed. Furthermore, the impacts of different runway light types and positions on sky background luminance are explored, leading to the proposal of an optimized runway lighting scheme. The results show that the representation of sky background luminance sensor data in RVR measurement systems for nighttime airport runways is limited. A deviation of over 90% exists between the sky background luminance of the runway entrance and the RVR measurement equipment location, resulting in a relative error in RVR measurements of over 18%. The centreline and entrance lights contribute significantly to the total sky background luminance. Lights closer to the observer contribute more luminance. In the second proposed scheme, modifying the lighting range to 600 m yields the highest RVR improvement, with an optimization magnitude of over 5% across all visibility ranges.

Fast Optimization of the Installation Position of 5G-R Antenna on the Train Roof

Fast Optimization of the Installation Position of 5G-R Antenna on the Train Roof

Optimization of sensor mounting position and pose in rotary kiln belt center measurement

Abstract To solve the problem that the measurement accuracy of the center of the wheel belt decreases during the adjustment of the center axis of the rotary kiln, a method of sensor installation position optimization based on dynamic simulation analysis and a simple small model is proposed and implemented in this paper. In this method, the coordinates of the laser points on the surface of the belt are obtained by using the sensor laser beam, and then the center position of the belt is obtained by fitting the coordinates of 6 laser points on the surface of the belt. Then V-rep dynamic simulation software is used to analyze the coordinates of the center position of the wheel under different sensor installation positions to find the sensor installation positions closest to the actual center of the wheel. Finally, the simulation results are verified by a simple small model. The experimental results show that this method can reduce the influence of belt deformation on the measurement of the center of the belt and find the most suitable sensor installation position. Taking the wheel with an ellipticity of 0.16% as an example, under the optimized sensor orientation, the error of the Y direction of the center of the wheel is 0.4 mm, and the error of the Z direction of the center of the wheel is 0.73 mm. By this method, the center accuracy of the existing measuring wheel is optimized from about 2 mm to less than 1 mm.

MatDEM-based study of disc cutter force model in open TBM tunnels: Incorporating installation radius and synergistic effects

The prediction of rock cutting force is critical for tunnel boring machine performance and cutterhead design. This paper presents a novel model for rock cutting force prediction based on the Colorado School of Mines (CSM) model, which incorporates the installation position of disc cutters by introducing installation radius and synergistic effect factors. Linear cutting tests in the laboratory and large-scale rotary cutting simulations in MatDEM software were conducted to examine the impact of these factors. Results indicate that the normal and rolling forces increase and stabilize as the installation radius increases. The synergistic effect produces three force modes in a cutting circle, with mode α having the largest cutting force, mode β having a smaller force, and mode γ having the smallest force. The impact of installation radius and synergistic effect varies with rock-cutter parameters. Multiple regression analysis was used to determine the introduced factors. The proposed model was validated with rock strength and operation data from the Irtysh River conveyance project. The results demonstrate that the proposed model outperforms the CSM model in predicting cutting force in field conditions.

A reconstruction method of stress fields, bending moments and wave parameters for floating nuclear power plants through regular wave identification

Floating nuclear power plants (FNPPs) have the potential to supply abundant electricity, hot water, and freshwater resources for offshore islands and offshore oil and gas extraction platforms. However, the consequences of a nuclear reactor accident can be extremely serious. In addition, there may be many uncertain factors in the actual operation of FNPPs. These factors lead to higher structural safety requirements. So， developing more scientific structural monitoring methods is an effective way to enhance the structural safety of FNPP. Traditional hull monitoring schemes can only track bending and torsional forces on specific cross-sections, failing to identify the overall stress field of the entire vessel structure. The paper proposes a reconstruction method for the stress field, bending moment distribution, and wave parameters of FNPP using regular wave identification. Initially, irregular waves are decomposed into a linear combination of multiple regular waves with different amplitudes and frequencies. Subsequently, the strains induced by these regular waves on the FNPP are utilized as basic functions to establish a mathematical model for reconstructing the stress field. The stress field, bending moment distribution, and wave parameters of the FNPP can be reconstructed by identifying the combination coefficients of the regular wave loads. The ill-posedness of the mathematical model for stress field reconstruction has the potential to significantly impact the accuracy of the stress field reconstruction, which was addressed by optimizing the sensor installation position in this study. Meanwhile, the optimization of the sensor installation position greatly reduces the dimensionality of mathematical models. Finally, a numerical study, i.e. FNPP being designed by China, was used to validate the accuracy of the proposed stress field reconstruction algorithm. The reconstructed stress field of the FNPP closely matched the original stress distribution under various irregular wave conditions.

Installed nacelle aerodynamics at cruise and windmilling conditions

PurposeThe decrease in specific thrust achieved by Ultra-High Bypass Ratio (UHBPR) aero-engines allows for a reduction in specific fuel consumption. However, the typical associated larger fan size might increase the nacelle drag, weight and the detrimental interference effects with the airframe. Consequently, the benefits from the new UHBPR aero-engine cycle may be eroded. This paper aims to evaluate the potential improvement in the aerodynamic performance of compact nacelles for installed aero-engine configuration.Design/methodology/approachDrooped and scarfed non-axisymmetric compact and conventional nacelle designs were down selected from a multi-point CFD-based optimisation. These were computationally assessed at a set of installation positions on a contemporary wide-body, twin-engine transonic aircraft. Both cruise and off-design conditions were evaluated. A thrust and drag accounting method was applied to evaluate different aircraft, powerplant and nacelle performance metrics.FindingsThe aircraft with the compact nacelle configuration installed at a typical installation position provided a reduction in aircraft cruise fuel consumption of 0.44% relative to the conventional architecture. However, at the same installation position, the compact design exhibits a large flow separation at windmilling conditions that is translated into an overall aircraft drag penalty of approximately 5.6% of the standard cruise net thrust. Additionally, the interference effects of a compact nacelle are more sensitive to deviations in mass flow capture ratio (MFCR) from the nominal windmilling diversion condition.Originality/valueThis work provides a comprehensive analysis of not only the performance but also the aerodynamics at an aircraft level of compact nacelles compared to conventional configurations for a range of installations positions at cruise. Additionally, the engine-airframe integration aerodynamics is assessed at an off-design windmilling condition which constitutes a key novelty of this paper.

Study on the uniform flow in adsorption device with perforated plate distributor

The adsorption device is widely used in the purification of impurity-containing wastewater, which is of great significance. However, the problem of non-uniform distribution of liquid in the packed bed has a large impact on the adsorption process. In the current study, CFD is used to simulate the fluid flow state during the adsorption process based on the physical modelling of the adsorption device, where the packed bed is modelled as a porous medium. By studying the effect of hole distribution, perforation rate, thickness and installation position of the perforated plate on flow uniformity and bed pressure drop, the influencing factors affecting the uniform distribution of fluid and pressure drop are discussed. Results show that changing the hole array did not have a significant effect on the fluid uniformity. When the perforation rate of the distributor is 15–29.4 %, the pressure drop is smaller and the flow distribution uniformity is better. The non-uniformity of flow field decreases first and then increases continuously with the increasing of the thickness. When the thickness of the perforated plate is between 10 and 30 mm, the overall performance is the best. Increasing the distance between the perforated plate and the inlet can reduce the impact strength of high-speed fluid on the perforated plate and improve the flow uniformity and increasing the inlet flow rate of the fluid can improve the uniformity of the flow field within a certain range, but it will increase the fluid flow loss.

One-Shot Any-Scene Crowd Counting With Local-to-Global Guidance.

Due to different installation angles, heights, and positions of the camera installation in real-world scenes, it is difficult for crowd counting models to work in unseen surveillance scenes. In this paper, we are interested in accurate crowd counting based on the data collected by any surveillance camera, that is to count the crowd from any scene given only one annotated image from that scene. To this end, we firstly pose crowd counting as a one-shot learning task. Through the metric-learning, we propose a simple yet effective method that firstly estimates crowd characteristics and then transfers them to guide the model to count the crowd. Specifically, to fully capture these crowd characteristics of the target scene, we devise the Multi-Prototype Learner to learn the prototypes of foreground and density from the limited support image using the Expectation-Maximization algorithm. To learn the adaptation capability for any unseen scene, estimated multi prototypes are proposed to guide the crowd counting of query images in a local-to-global way. CNN is utilized to activate the local features. And transformer is introduced to correlate global features. Extensive experiments on three surveillance datasets suggest that our method outperforms the SOTA methods in the few-shot crowd counting.

Dimensional synthesis of motion generation of a planar four-bar mechanism

A motion generation method for a planar four-bar mechanism without prescribed timing is proposed in this article. A characteristic of coupler points is found: for the coupler points of a four-bar mechanism in a standard installation position rotated by the corresponding input angle clockwise around the origin of the Cartesian coordinate system xOy, the generated points lie on the feature coupler circles. Next, based on this, the design process is divided into three steps. In the first step, the relative input angles, the relative coupler angles and five geometric parameters of the desired four-bar mechanism are optimized. In the second step, the basic dimensional types and initial input angle are determined, and then, the input angles are obtained. In the third step, the real size of the desired linkage mechanism is calculated. Because the dimension of the design variables in each step is exceptionally small, the motion synthesis method can yield design solutions with high precision in a short time. Six comparison examples are presented to demonstrate the efficacy of the proposed method. In addition, the method is used to design a robot for lower limb rehabilitation for application to the human foot.

Research on thermal mass flowmeter (TMF) measurement of coalbed methane (CBM) well production profile.

Developing coalbed methane (CBM) aligns with global climate change policies and sustainable energy development. Currently, methods for testing gas and water production profiles in CBM wells are diverse. A downhole constant-flow thermal mass flowmeter (TMF) was designed to address the difficulty of testing gas production above the liquid level in low-yield CBM wells. A computational fluid dynamics model with a 125mm diameter pipe was established to study the TMF's temperature field and thermal equilibrium time as the gas flow rate changes. The relationship curve between temperature, thermal equilibrium time, and flow rate changes was obtained. The effect of the TMF's installation angle and position in the wellbore on resolution was discussed. Experimental research on a multiphase flow simulation apparatus showed that the TMF has good response capability and testing accuracy in a gas environment. Measuring downhole flow rates using the thermal flow meters is feasible and meets the testing requirements of CBM wells.

Closed-loop Control System Design of Wind Rope Hoisting of Transmission Tower

Abstract The traditional wind rope (tricing pendant) hoisting method of power transmission towers mainly relies on manpower to observe the posture of the hanger and adjust the retraction and release speed of the control rope, so as to avoid the scraping of hanger and the assembled tower body. In this paper, the ADAMS/Cable modeling tool is used to establish the transmission tower hoisting dynamic model with the JC27151CG tower as the object, and the reasonable installation position of the tricing pendant retraction system is analyzed. And based on the reasonable installation position, the hoisting strategy and hoisting control system of JC27151CG tower are studied. The main control system hardware of the control device mainly includes Delta PLC, servo driver, AC contactor and DC relay. The main control program is divided into two modes, manual and automatic, with a closed-loop control servo motor system. The manual mode operates the servo motor through buttons to realize forward and reverse rotation. In automatic mode, the system intelligently adjusts the lifting speed and attitude according to the data of the navigation system to ensure a smooth and safe lifting process. The research outcomes not only offer novel theoretical perspectives and methods for the hoisting of power transmission towers but also provide robust technical support for practical engineering operations.

Mitigating sub-synchronous oscillation using intelligent damping control of DFIG based on improved TD3 algorithm with knowledge fusion

The occurrence of sub-synchronous oscillation (SSO) phenomenon in doubly-fed induction generators (DFIGs)-based wind turbines threatens the secure and stable operation of the power grid. Conventional sub-synchronous damping controllers encounter challenges in adapting to the dynamic operating conditions of power systems. This paper introduces an Intelligent Sub-Synchronous Damping Controller (I-SSDC) for DFIGs that integrates deep reinforcement learning (DRL) and knowledge to address the limitations of conventional methods for SSO mitigation. The initial step involves formulating a framework for I-SSDC using the improved twin delayed deep deterministic policy gradient (TD3) algorithm incorporating Softmax. Following this, a surrogate model is constructed, employing Weighted Linear Regression and regularization. This model is designed to identify the predominant influencing factors of SSO, focusing on the selection of the output signal (installation position) to optimize decision-making in I-SSDC. The objective is to enhance the controller’s environmental adaptability and interpretability. Moreover, knowledge and experience related to SSOs are integrated into agent training to improve the exploration efficiency of the agent. Case studies under various operating conditions of the test power system validate the efficacy of the proposed I-SSDC in suppressing SSOs.

Dynamic analysis of a propulsion shaft system considering the flexible coupling and motor isolations

This paper presents a dynamic model for the propulsion shaft system of an unmanned underwater vehicle. The model considers the effects of the flexible coupling and motor isolators. The motor bearings, shaft support bearings, thrust bearing and propeller are considered. A multi-degree of freedom isolation model for the motor stator is established. The coupling effects of shaft, motor bearings, shaft support bearings and motor excitation are considered. A finite element mode analysis and forced vibration experiment is conducted to provide the verification. The influences of the shaft speed, flexible coupling stiffness, motor isolation stiffness and installation position on the system vibrations are studied by using the numerical model. This study could provide some guidance for the dynamic analysis and vibration optimization of the propulsion shaft systems of UUVs.

Improving Maintenance Operations on Raw Material Conveying Equipment by Using TRIZ Technique

The objective of this research is to improve equipment used for conveying raw material in the construction material industry and establish standard procedures for maintenance by applying Theory of Inventive Problem Solving (TRIZ). Research methodology consists of 1) studying the maintenance system of raw material conveying equipment of the case study company 2) collecting data and prioritizing problems using a Pareto chart, 3) setting goals, 4) analyzing the causes of the problems with Why-Why analysis and 3 GEN techniques, 5) concluding the results. Results from the study in 2022 showed that problem occurred at sieves and vibrator base used for filtering raw materials resulting in a high maintenance frequency of 28 times. The causes of the problem are the improper shape of the sieves and the installation position of the sieve vibrator including the carelessness of the worker to turn off the vibrator. This research solved the problems by applying TRIZ as guidelines for designing new sieves and applying Total Productive Maintenance (TPM) in establishing standard procedures for maintenance. The results of the improvement during May-November 2023 showed that the frequency of sieves maintenance decreased to 3 times equivalent to 6 times per year approximately, achieving the goal of less than 14 times/year. The MTBF increased from the original 171.67 hours to 1,055.91 hours and the MTTR decreased from 3.04 hours to 2.55 hours. It can be concluded that TRIZ can be applied to improve the material conveying equipment by significantly reducing the maintenance frequency.

Multi‐objective reliability‐based robust design for a rock tunnel support system using Pareto optimality

AbstractIn the context of rock material and modeling uncertainties, the optimization of rock tunnel support systems is often conducted by selecting the most cost‐effective solution among several feasible options that typically rely on the engineer's experience, potentially leading to overlooking the most optimal design. To improve such a limitation, this paper presents a multi‐objective reliability‐based robust design, considering the cost, safety, and design robustness systematically while maintaining the computational efficiency. In this framework, the uncertainty‐based reliability constrains is performed using the first‐order reliability method (FORM) and an improved Hasofer–Lind–Rackwits–Fiessler recursive algorithm (iHLRF‐x). The design robustness, in terms of sensitivity index (SI), is evaluated using the normalized gradient of the system response to the noise factors, which can be efficiently obtained from the output of FORM analysis. Then, the Pareto front revealing the tradeoff between multiple objectives can be directly generated using the proposed optimization framework. To illustrate the effectiveness of this procedure, a set of the optimal design combinations of the shotcrete thickness and installation position for the exampled rock tunnel are obtained, and new perspectives pertaining the success of the reliability‐based robust designs are provided.