Simple Engineering Method Research Articles

CORONATING VOLTAGE DIVIDER OF MEGAELECTRONVOLT ACCELERATING TUBE

This paper describes the methodology of high-voltage testing of the voltage divider of a positively charged ion accelerating tube for energies up to 1000 keV. The test results are presented, and a simple engineering method for calculating the corona voltage divider is proposed.

Aggregation-Induced Emission-Active Organic Nanoagent with High Photothermal Conversion Efficiency for Near-Infrared Imaging-Guided Tumor Photothermal Therapy.

Photothermal therapy (PTT) provides a great prospect for noninvasive cancer therapy. However, it is still highly challenging to construct photothermal agents (PTAs) with the desired performances for imaging-guided PTT applications. Herein, a D-A-D-type naphthalene diamine (NDI)-based photothermal nano-PTAs NDS-BPN NP with near-infrared region (NIR) emission at 822 nm, aggregation-induced emission (AIE), high photothermal conversion efficiency (55.05%), and excellent photothermal stability is successfully designed and prepared through a simple two-step engineering method by using a new AIE molecule NDS-BPN and DSPE-PEG2000 as precursors. The prepared PTT nanoagents NDS-BPN NPs have been further applied for efficient photothermal ablation of cancer cells in vitro and also achieved the NIR fluorescent image-guided PTT tumor therapy in vivo with satisfactory results. We believe that this work provides an attractive NIR AIE NDI-based nano-PTA for the phototherapy of tumors as well as develops the construction strategy of NDI molecular-based photothermal nanoagents with desired performances for imaging-guided PTT.

Interface Engineering by Unsubstituted Pristine Nickel Phthalocyanine as Hole Transport Material for Efficient and Stable Perovskite Solar Cells.

Lead halide perovskite solar cells (PSCs) have been rapidly developed in the past decade. With the development of a PSC, interface engineering plays an increasingly important role in maximizing device performance and long-term stability. We report a simple and effective interface engineering method for achieving improvement of PSCs up to 20% by employing unsubstituted pristine nickel phthalocyanine (NiPc). Thermal annealing of NiPc improves the interface between NiPc and perovskite because of the incorporation of NiPc molecules into the perovskite grain boundaries, which creates improvements in hole extraction from the perovskite absorber layer, as evidenced by time-resolved photoluminescence measurements. This significantly improves the charge transfer and collection efficiency, which are closely related to the improvement of the interface between perovskite and NiPc.

Sheep bone powder modified PVDF membrane for highlyefficient oil-in-water emulsion separation

BackgroundThe wetting properties and roughness modification of membrane surfaces are crucial for their application in emulsion separation. However, traditional membrane modification methods suffer from high cost, complex preparation, and secondary pollution. MethodsIn this study, a novel, simple, and economical interfacial engineering method was developed using tannic acid (TA), sodium alginate (SA), and sheep bone powder (BP) as raw materials. Through vacuum filtration, these materials were deposited onto polyvinylidene fluoride (PVDF) membrane to fabricate superhydrophilic/underwater superoleophobic filtration membrane (PDBS). BP induced surface roughness and wetting properties to the membrane, while preserving the porous structure of the substrate membrane. The complex formed by TA and SA encapsulated BP onto the surface of PVDF microfiltration membrane, enhancing its mechanical properties. Significant FindingsThe prepared membrane exhibited a membrane flux of 347 Lm−2h−1 bar−1 and a separation efficiency of 99.9 % for emulsified oil. Furthermore, after soaking in NaCl solution for 30 h, the membrane still showed excellent stability. Therefore, this study developed a new membrane surface modification strategy with promising application prospects in oily wastewater treatment.

Инженерная методика определения температурного состояния металла при его нагреве

Currently, the determination of the temperature profile of the furnace required to ensure the specified heating parameters of the metal is carried out using the temperature measurement method or mathematical models. They are most based on solution of the differential equation of non-stationary thermal conductivity. Previously, the thermal diagram method of I.D. Semikin was widely used. It allows us, under given heating conditions, to determine heating duration. In practice, it is important to develop a simple engineering method that would allow the temperature field of the metal to be determined with sufficient accuracy under given heating conditions. The development is based on the thermal diagram method of I.D. Semikina. But at the same time, the final equation describing the heat balance of the metal within the furnace zone is solved relative to the enthalpy of the metal at the exit from the zone. The specified heating conditions (productivity, zone temperature) are used to determine the quantities of the right-hand side of the equation (time heating, average heat flux density). The authors have proposed the method for continuous furnaces of various types (push-type and with a mechanized hearth) that allows us for a given productivity and temperature profile of the furnace to calculate the change in the temperature state of the metal for all heating zones, from the moment of loading to the release of metal. The adequacy of the proposed methodology has been tested for two types of furnaces. For methodical push-type furnaces, the results obtained have been compared to the results of modeling the temperature state of the metal using a numerical method. The discrepancy between the results after passing the inertial heating period does not exceed 1 %. For a walking-beam furnace the calculated value of the metal surface temperature after the furnace has been compared with the results of operational measurements. The discrepancy is less than 2 %. The totality of the results obtained ensures the achievement of the research goal. The proposed method is based on the heat balance equation and allows us to consider it to be correct. It is an engineering method and quite simple to implement. The method is recommended to be used to design furnaces and to calculate the temperature profile of furnaces by engineering departments of metallurgical enterprises.

Modelling and Thermographic Measurements of LED Optical Power.

This paper presents a simple engineering method for evaluating the optical power emitted by light-emitting diodes (LEDs) using infrared thermography. The method is based on the simultaneous measurement of the electrical power and temperature of an LED and a heat source (resistor) that are enclosed in the same plastic packaging under the same cooling conditions. This ensures the calculation of the optical power emitted by the LED regardless of the value of the heat transfer coefficient. The obtained result was confirmed by comparing it with the standard direct measurement method using an integrated sphere. The values of the estimated optical power using the proposed method and the integrated sphere equipped with a spectrometer were consistent with each other. The tested LED exhibited a high optical energy efficiency, reaching approximately η ≈ 30%. In addition, an uncertainty analysis of the obtained results was performed. Compact modelling based on a thermal resistor network (Rth) and a 3D-FEM analysis were performed to confirm the experimental results.

Engineered lytic phage of Bacillus cereus and its application in milk

Phages have been approved for use in the food industry to control bacterial contamination in some countries. However, their broader adoption is hindered by some limitations. For instance, the persistence of infectious phages in the food industry can lead to the emergence of resistant bacteria, which negatively impacts the long-term effectiveness of phages. Additionally, the narrow host range of phages limits their effectiveness against various strains. To address these deficiencies, phage engineering has been proposed as a rational approach for modifying phages. In this study, we developed a simple and efficient engineering method for Bacillus cereus phage, using DK1 as an example, to reduce the number of residual phages and expand its range of hosts. Specifically, we knocked out the appendage gene, which codes for the receptor-binding protein, to produce phage progeny with structural defects in their appendages, resulting in the loss of infectivity after host elimination. Furthermore, we used plasmid-mediated means to express different appendage proteins during phage preparation, which allowed altering the host spectrum of the engineered phages without gene insertion. In practical applications, our engineered phages effectively reduced the number of B. cereus in milk and prevented the amplification of active progeny. Our strategy transformed phages from active viruses into more controllable antibacterial agents, making them safer and more efficient for the prevention and control of B. cereus. Moreover, we believe this strategy will help drive the use of engineered phages in the food industry.

A general correlation between ductile fracture toughness and unified constraint parameter for different materials

In structural integrity assessment based on the two-parameter approach with considering constraint, it is an important step to establish a correlation between fracture toughness and constraint parameter for a specific material. But it is difficult and costly. In this work, based on a large number of ductile fracture toughness JC data measured from specimens with different geometries and crack sizes for different materials and finite element calculation of a newly developed unified constraint parameter Ad* for each specimen, a general correlation equation between JC and Ad* has been established. This correlation equation may be applied to predict constraint-dependent fracture toughness for different materials and structures, and its prediction capability has been validated by a great quantity of experimental fracture toughness data of various specimen geometries and materials (including welded joints). This correlation equation has a wide application range and may provide a simple and convenient engineering method to estimate constraint-dependent ductile fracture toughness.

Stable Cycling with Intimate Contacts Enabled by Crystallinity-Controlled PTFE-Based Solvent-Free Cathodes in All-Solid-State Batteries.

All-solid-state batteries (ASSBs) employing Li-metal anodes and inorganic solid electrolytes are attracting great attention due to high safety and energy density for next-generation energy storage devices. However, the volume change of cathode active materials can cause contact loss, resulting in charge carrier isolation, heterogeneous current distribution, and poor electrochemical properties in ASSBs. Here, a simple, yet effective, solvent-free electrode engineering approach with polytetrafluoroethylene (PTFE) as a binder for ASSBs is reported, enabling intimate contact and stable interfaces with the cathode. It is substantiated that the crystallinity of PTFE can be controlled depending on the heat history, and highly crystalline PTFE displays robust mechanical properties. High-nickel LiNi0 . 8 Mn0.1 Co0.1 O2 cathode prepared with crystalline PTFE show improved cycle and rate performances in ASSBs. In addition, it is revealed that the intimate contact between cathode particles with a stable cathode electrolyte layer is maintained during cycling by postmortem studies. This simple engineering method can be applied to prepare cathodes with a variety of active materials and solid electrolytes in ASSBs.

Engineering method for calculating fluid flow in pipes with different cross sections in energy and technological processes

The flow of liquid through pipes with various configurations is found in many energy and technological processes. Knowledge of the distribution of velocity and flow through these pipes allows hydrological engineers to find resistance through the pipes and optimize the fluid pumping process. The article suggests a simple engineering method for finding the velocity over pipe sections

Evaluation of the Idle time of Single-Chain and Double-Chain Overhead Power Lines of 6–10 kV by Methods of Queuing Theory

The aim of this work is to substantiate the idle time evaluation of the overhead power line (OPL) according to the reliability indicators of its main elements using the probability value of the overhead power line availability factor. Statistical studies of the 17 OPL were performed to achieve this goal. The results of the statistical data processing made it possible to consider over-head lines as objects of a multiple action, and their failure and recovery flows as the primitive Poissonian flows. The calculation of the Wilcoxon and Pearson criteria confirmed the uniformi-ty of the statistical material both in terms of failure times and recovery time for all 17 studied OPL, which allowed combining the uniform statistical data into two representative samples, ac-cording to failures and recoveries, for the generalized district OPL and calculate its reliability indicators. The most significant result is the justification of applying queuing theory methods to evaluate the idle time of 6–10 kV single-chain and double-chain of overhead lines. The signifi-cance of the results obtained consists in that a simple engineering method is proposed to evalu-ate the availability factor of the overhead power line according to the reliability indicators of its main elements, which allows predicting the idle time of the overhead line for the upcoming cal-endar year of its operation. The newly obtained availability factors of the main overhead line elements can be used in the overhead power lines’ design.

Engineering Metal Alloy Nanocrystals Anchored on N‐Doped Nanoporous Carbon for Li‐O2 Batteries

AbstractThe development of highly efficient oxygen catalysts is crucial for improving the storage capacity and stability of Li‐O2 batteries. Herein, we report a simple engineering method to prepare the composite electrocatalyst of the CoNi alloy nanoparticles anchored on the N‐doped porous carbon substrate (CoNi/NC), which exhibits the enhanced electrocatalytic performance for the Li‐O2 batteries due to the synergetic effect between the bimetal CoNi alloy and the N‐doped porous carbon framework. The porous structure can expose more active sites, enhance the mass transfer, and temporarily store the Li2O2 intermediate. The CoNi/NC catalyst makes the batteries show a high discharge capacity of 17783 mA h g−1, a low overvoltage of 1.03 V, and long cycle life of 194 cycles. These results indicate that such a simple engineering preparation method can benefit the large‐scale production of high‐efficiency and cost‐effective electrocatalysts for energy applications.

Numerical method for calculating the nozzle thrust of a wide-range rocket engine

A numerical method for calculating the thrust of a wide-range rocket engine nozzle has been developed. This type of engine is equipped with an annular nozzle with a flat central body and is designed to operate in the upper atmosphere and in vacuum. The nozzle forms a jet converging to the axis of symmetry due to which a more compact torch of the working fluid is formed. Nozzles of this type have important design advantages over conventional external expansion nozzles. They are more compact, simpler in terms of cooling, but they have increased losses in the bottom region due to the presence of a flat bottom near the central body. Therefore, the design of such engines needs parametric optimization. Currently, for engines equipped with an annular nozzle with a flat central body, there are no validated methods that would allow parametric optimization. The characteristics of the jet, the loss of specific impulse, and the magnitude of thrust for a given type of nozzle depend on three main parameters: the area of the bottom region of the central body, the area of the throat section, and the angle of rotation of the inner edge of the nozzle to the axis of symmetry. The gas flow in the bottom region is accompanied by complex shock-wave processes that require a lot of time for numerical calculations. To optimize the design of the nozzle, it is required a simple engineering method to calculate the thrust of the nozzle according to its main parameters. The calculation of the nozzle thrust is based on the integral distribution of pressure forces over its surface obtained by performing numerical calculations in a wide range of external pressure. The Reynolds-averaged Navier-Stokes equations closed by the SST-modification of the k-ω turbulence model are solved. Based on the results of numerical simulation, the calculated coefficients for one-dimensional engineering dependencies are determined; they make it possible to calculate the speed and pressure in a random section of the combustion chamber and engine nozzle. A simple engineering method for calculating the thrust of the chamber nozzle of a wide-range rocket engine has been developed. The technique is verified by comparison with the results of a numerical experiment. The problem of parametric optimization of the rocket engine combustion chamber, capable to operate in a wide range of altitudes, was solved, and it is of interest to the space industry. The developed method of calculation makes it possible to carry out a wide range analysis of the influence of the ratio of geometric dimensions, regime parameters on the thrust of the combustion chamber and nozzles of a wide-range rocket engine, and to estimate the thrust value at different engine operating heights.

PLL Synchronization Stability of Grid-Connected Multiconverter Systems

Phase-locked loop (PLL) synchronization instability of grid-connected converters under grid faults is a serious concern, in particular for multiconverter plants/stations connected to a weak grid. The multiconverter interaction can lead a large number of converters to lose stability successively. The PLL synchronization instability of a single-converter system has been well studied previously, but it remains unclear how the multiconverter interaction affects the synchronization stability. This article is aimed to fill this gap, in which multiconverter modeling and interaction analysis, stability level assessment, and stability improvement are addressed. It is found that the interaction is detrimental to the near-end converters, but it is beneficial to the far-end ones. From the most prone-to-instability converter, a simple method is proposed to efficiently assess the synchronization stability level of the entire system. In the aspect of improving synchronization stability, the existing methods are evaluated comparatively, and a simple feedforward-compensated PLL is proposed to address the disadvantage of the existing methods. Among them, recommendations are provided by considering multiple aspects of performance and different application requirements. The performance of the methods is verified by hardware-in-the-loop experiments. The results of this study provide a simple engineering method for grid-connected multiconverter synchronization stability assessment and practical guidelines for the selection of stability improvement methods.

Promoting polysulfides redox conversion by sulfur-deficient ZnS1−x hollow polyhedrons for lithium-sulfur batteries

Lithium-sulfur (Li-S) batteries are deemed as the attractive systems for high-energy storage. However, the polysulfides shuttling with slow redox kinetics has seriously hindered their practical applications. Herein, sulfur-deficient zinc sulfide (ZnS1−x) hollow polyhedrons are synthesized as the multifunctional sulfur host material via the sulfurization and high-temperature annealing method. The unique hollow structure could supply adequate void spaces for sulfur loading and alleviate volumetric expansion of sulfur upon the cycling process. Besides, ZnS1−x hollow polyhedrons with abundant sulfur vacancies can provide effective adsorption sites to chemically immobilize polysulfides and enhance polysulfides redox conversion as confirmed by theoretical calculation results and electrocatalytical experiments. Thus, the S/ZnS1−x cathode delivers the remarkable initial capacity (1206 mAh g−1 at 0.2 C) and excellent cycling stability (592 mAh g−1 after 500 cycles at 1 C). The study points out the idea of functional cathode material for Li-S batteries based on a simple yet efficient vacancy engineering method.

CNN-Based PD Hand Tremor Detection Using Inertial Sensors

Parkinson's disease (PD) affects tens of millions of people worldwide, simple and reliable engineering method assist doctors in diagnosis and treatment is necessary. In this letter, a convolutional neural network (CNN)-based PD hand tremor detection method is proposed. The wrist acceleration information of both PD patients with hand tremor and healthy subjects are acquired by wearable device with inertial sensor. Then a nine-layer CNN model is built to identify PD hand tremor. Through the comparing experiments and cross-validation, it is proved that this method can detect PD hand tremor symptoms effectively and has better performance than typical machine learning methods.

Fast optimization of outriggers for super-tall buildings using a sensitivity vector algorithm

This study proposes a simple engineering method to fast determine the quantity and placement of outriggers for super-tall buildings. At first, a sensitivity vector algorithm (SVA) is proposed by applying the vector dot-product algorithm to optimize outriggers in super-tall buildings towards the constraints of the maximum interstory drift . The proposed SVA is then demonstrated by a super-tall building under the wind load control and verified by the exhaustive search algorithm (ESA). Finally, the SVA is applied to optimize the outriggers for a super-tall building in the high-intensity seismic area . The results show that the optimal outrigger scheme relates to both the quantity and placement, rather than simply proportional to the quantity. Increasing the quantity of outriggers can reduce the interstory drift in the adjacent area of the added outrigger but may increase the interstory drift in other zones. The sensitivity vector algorithm can be used for the optimization of outriggers not only for the single-mode-driven wind load, but also for the multi-mode-driven seismic load, which is very helpful for the preliminary design of super-tall buildings. • Sensitivity vector algorithm is proposed to optimize quantity and placement of outriggers using vector dot-product algorithm. • Optimal outrigger scheme relates to both the quantity and placement, rather than simply proportional to the quantity. • Sensitivity vector algorithm can be used for both the single-mode-driven wind load and the multi-mode-driven seismic load.

Vortex detection criteria assessment for PIV data in rotorcraft applications

The aim of the article is to propose a simple engineering method for identifying and characterizing vortical structures within a flow field measured with a classic two-component PIV measurement system. Some of the most popular vortex detection systems are briefly presented. Of these, many fail if spurious vectors are present within the flow field due to poor PIV image quality or due to particle voids in the vortex core. The chosen method is the Γ2-criterion. The investigated method is robust and reliable, because it is based on the velocity field topology without using velocity derivatives sensitive to the spurious vectors. The method is tested on synthetic velocity fields of ideal vortices and on real PIV velocity field of a four-bladed rotor wake. The synthetic velocity fields reproduce single and multiple vortices to investigate the mutual interaction and the effect on the vortex detection criteria. The synthetic velocity fields have different spatial resolution, noise level, and different particle void to perform a parametric assessment. Other vortex identification schemes are applied for comparison. Information on how to use the criterion for different noise conditions, particle void, and presence of multiple vortices is provided.

An elaborate sensor system based on conducting polymer-oligosaccharides in hydrogel and the formation of inclusion complexes

In this study, electrically conductive materials composed of carboxylated polypyrrole (PPy(COOH)) and nontoxic oligosaccharide molecules (cyclodextrin, CD) were prepared and incorporated into biocompatible hydrogels for use as versatile sensors. The major component, carboxylated polypyrrole nanotubes (PPy(COOH) NTs) were fabricated using microemulsion polymerization and a critical sensing medium CD molecule was introduced via a simple surface engineering method. The resulting PPy(COOH)-CD NT hybrid complexes were incorporated into a hydrogel matrix for biocompatible applications. Consequently, a convenient sensor geometry was constructed by mounting the hydrogel on a gold micropattern for the detection of toxic substances. The feasibility of the produced sensor system was demonstrated, and the sensor performance was measured extensively using electrical measurements. It was found that the sensor could detect a model compound (methyl paraben, MPRB) at concentration as low as 1nM. This study provides useful information for future research activities in relevant fields.

Engineering Method for Analysis of the Ability to Strain-Hardening of Steels

The strain-hardening ability has been estimated using a methodologically simple engineering criterion. A simple engineering method estimates the ability of metals and alloys to strain-hardening by the hardness increase determining. The Rockwell hardness has been measured at the bottom of the indentation cup of the Brinell press indenter. The strain-hardening tendency is investigated by the “two hardness-measuring instruments” method for two austenitic manganese steels, 110G13L and 110G6L, with different austenite stability to strain martensitic transformation. This hardness estimating method can be applied without making special samples and using deforming equipment.