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With the transition from supplying ships with direct current to alternating current, plus the increase in the number of electricity consumers within the coastline region, as well as with the construction of steel quays and docks and reinforced steel quays, the conditions have been created for the occurrence of wandering exchange currents in the sea. Corrosion due to these currents considerably exceeds all expectations. In this work, the rate of steel corrosion in synthetic sea‐water has been investigated in an alternating electric field. Electro‐chemical parameter measurements determining corrosion rate were performed on samples in sea‐water in an alternating current field and compared with the sample — applying a “blind test” — without an electric field. All measurements were performed at an electrolyte temperature of 20°C. Corrosion rate was investigated in dependence on the current density. The following factors were applied as measures of corrosion rate: specific concentration of Fe ions in the electrolyte and the change of potential of the steel electrode polarized within alternating electric field. Measurement results shown that in the sea‐water with an alternating electric field an increase in the corrosion of steel takes place, exceeding expected amounts. The change of steel potential in alternating current field is proportional to the corrosion rate and can be very simply applied for estimation of corrosion rate due to alternating currents.

The purpose of this study is to estimate the price and life-saving potential of alternate foods. The sun could be blocked by asteroid impact, supervolcanic eruption or nuclear winter caused by burning of cities during a nuclear war. The primary problem in these scenarios is loss of food production. Previous work has shown that alternate foods not dependent on sunlight, such as bacteria grown on natural gas and cellulose turned into sugar enzymatically, could feed everyone in these catastrophes, and preparation for these foods would save lives in a manner that is highly cost-effective.

This study estimates the price of alternate foods during a catastrophe in line with global trade and information sharing, but factors such as migration, loans, aid or conflict are not taken into consideration.

Without alternate foods, for a five-year winter, only approximately 10 per cent of the population would survive. The price of dry food would rise to approximately $100/kg, and the expenditure on this food would be approximately $100tn. If alternate foods were $8/kg, the surviving global population increases to approximately 70 per cent, saving >4billion lives.

A nongovernmental mechanism for coordinating the investments of rich people may be possible. Identifying companies whose interests align with alternate food preparations may save lives at a negative cost.

The probability of loss of civilization and its impact on future generations would be lower in this scenario, and the total expenditure on food would be halved.

Preparation for alternate foods is a good investment even for wealthy people who would survive without alternate foods.

With the rapid development of rail transportation and energy-delivery systems, such as buried oil and gas pipelines and high-voltage transmission lines, the alternating current (AC) corrosion of buried steel pipelines is becoming more serious. This paper aims to study the corrosion behaviours of Q235 buried steel pipelines induced by the alternating stray current, with a set of indoor simulated experiment apparatuses.

The corrosion of the coating holidays of the buried steel pipelines at various AC current densities from 0 to 200 A/m² in the soil-simulating environment was revealed by the electrochemical and weight-loss methods.

The results showed that the corrosion potential of the steel shifted negatively obviously and the corrosion rate of the steel increased with the increasing of AC current density. At a low AC current density, the negative deviation of the corrosion potential of the steel was small and the increase of corrosion rate was slight. However, the negative deviation of the corrosion potential was remarkable and the corrosion rate was greatly increased at a relative higher AC current density. The geometrical shape of the corrosion images indicated the corrosion forms changed from uniform corrosion to local corrosion due to the increase of AC interference.

Investigation results are of benefit to provide a new strategy to forecast and evaluate the AC-induced corrosion of the buried pipelines which could improve the safety of pipeline transportation.

This paper aims to raise awareness of a potential planning pitfall and provide recommendations on how to assess and improve upon current practices. In potential conflict areas, such as the Korean Theater of Operations (KTO), military forces are required to store a portion of their ammunition combat load within depots and ammunition supply points under the control of a servicing ammunition company. This necessitates a lengthy retrieval process, as the ammunition company does not have enough resources to serve all customers simultaneously.

The stored combat load (SCL) retrieval process is modeled as a parallel machine scheduling problem and simulated using synthetic requirements. The current system of retrieval is contrasted against a proposed alternate system through a series of simulations scaled across three factors: number of ammunition company Soldiers, number of customer units and number of magazines.

The proposed alternate system demonstrates a significant potential for reducing the makespan of the SCL retrieval process when more than half of the magazines store SCL for multiple customers and there are more than five customers per Soldier.

Transitioning military units from a peacetime standing to full combat readiness as quickly as possible is of immense value within the KTO and other hostile areas with established troops not actively engaged in combat.

This paper aims to understand the magnetohydrodynamics (MHD) mechanism in the molten pool under different modes of magnetic field. The comparison focuses on the Lorenz force excitation and its effect on the melt flow and solidification parameters, intending to obtain practical references for the design of magnetic field-assisted laser directed energy deposition (L-DED) equipment.

A three-dimensional transient multi-physical model, coupled with MHD and thermodynamic, was established. The dimension and microstructure of the molten pool under a 0T magnetic field was used as a benchmark for accuracy verification. The interaction between the melt flow and the Lorenz force is compared under a static magnetic field in the X-, Y- and Z-directions, and also an oscillating and alternating magnetic field.

The numerical results indicate that the chaotic fluctuation of melt flow trends to stable under the magnetostatic field, while a periodically oscillating melt flow could be obtained by applying a nonstatic magnetic field. The Y and Z directional applied magnetostatic field shows the effective damping effect, while the two nonstatic magnetic fields discussed in this paper have almost the same effect on melt flow. Since the heat transfer inside the molten pool is dominated by convection, the application of a magnetic field has a limited effect on the temperature gradient and solidification rate at the solidification interface due to the convection mode of melt flow is still Marangoni convection.

This work provided a deeper understanding of the interaction mechanism between the magnetic field and melt flow inside the molten pool, and provided practical references for magnetic field-assisted L-DED equipment design.

This paper aims to investigates a novel design of a modular moving magnet linear oscillating actuator (MMM-LOA) with the capability of coupling modules, based on their application and space requirements.

Proposed design comprised of modules, and modules are separated by using nonmagnetic materials. Movable part of the proposed design of LOA is composed of permanent magnets (PMs) having axial magnetization direction and tubular structure. Stator of the proposed design is composed of one coil individually in a module. Dimensions of the design parameters are optimized through parametric analysis using COMSOL Multi Physics software. This design is analyzed up to three modules and their response in term of electromagnetic (EM) force and stroke are presented. Influence of adding modules is analyzed for both directions of direct current (DC) and alternating input loadings.

Proposed LOA shows linear increase in magnitude of EM force by adding modules. Motor constant of the investigated LOA is 264 N/A and EM force per PM mass is 452.389 N/kg, that shows significant improvement. Moreover, proposed LOA operates in feasible region of stroke for compressor application. Furthermore, this design uses axially magnetized PMs which are low cost and available in compact tubular structure.

Proposed LOA shows the influence of adding modules and its effect in term of EM force is analyzed for DC and alternating current (AC). Moreover, overall performance and structural topology is compared with state-of-the-art designs of LOA. Improvement with regard of motor constant and EM force per PM mass shows originality and scope of this paper.

The important series of mechanical charging systems known generally as Indicators, have never been fully described, either from the historical or structural standpoint. Papers describing one or other of the individual varieties have been published from time to time during the period of thirty‐six years they have been in use, but except the partial notices of a select few published by Mr. F. J. Burgoyne and myself, nothing of a comprehensive or accurate nature has ever appeared. Before proceeding to describe each separate invention in its order, it may be well to enquire briefly into the reasons for the origin of a device which has called forth not a little ingenuity and inventive talent. When libraries were first established under the provisions of the various Acts of Parliament, two things happened as a matter of course in every district: a building, suitable or otherwise, was provided; and, the readers in a town increased in number to an enormous and unprecedented extent. Straitened means generally led to the provision of a cramped and inconvenient building, in which the space set apart for books was often ridiculously inadequate; with the result that lofty shelves were the rule, which secured economy of storage at the expense of rapidity of service. Previous experience in mechanics' institutes, or similar libraries, was found by the new librarian a useless criterion for public library needs, and especially as a guide to the multitude of readers and the variety of their demands. Delays in service occurred continually and the poor librarian was often abashed or offended at the freely expressed scepticism with which the public received his reports of books being out. From these factors was evolved the idea of the indicator, which by and by took practical shape as a machine for saving the legs of the librarian and his assistants from frequent and fruitless climbs to high shelves, and enabling readers to satisfy themselves that books were actually in use. The original indicators were intended only for showing, by means of numbers, the novels which were out or in, but since then a considerable number of libraries have applied them to all classes.

This paper aims to investigate the perception threshold (PT) of electrotactile stimulation under non-steady contact condition (NSCC) which is rarely considered in previous reports mainly because of the difficulty with experimental control. Three factors of NSCC are involved, including the current alternating frequency, the tapping interval of stimulation and the stimulating area of skin. The study is aimed at providing the basic PT data for design and application of wearable and portable electrotactile device.

The up-down method was selected to assess PT, and 72 experimental scenarios were constructed. During the study, we developed an experimental platform with the function of data record and programmable current stimulation. With psychophysical experiment, more than 10,000 data were collected. Furthermore, statics analysis and ANOVA test were opted for exploring the main factor influencing PT.

NSCC has different PTs on each body location, and PT has a positive correlation with frequency. In general, PT in NSCC is significantly lower than that in SCC. In some cases, it can be lower by more than 60 per cent. In addition, women have a lower PT than men across all age groups, and the younger is generally more sensitive than the older in electro-sensation.

Limited factors of NSCC were considered in this study. Contact time and break interval should be investigated in the future work.

The paper includes implications for the development of smart electrotactile device.

This paper fulfills a challenge in assessing the PT under NSCC.

Stray currents in the ground are those which have their origin in electrical power and traction systems, as distinct from currents of voltaic origin. The electrical industry is concerned with the control of such stray currents, partly because of its awareness of responsibility towards the authorities operating other underground services, and partly because of its own very large capital investment in underground cables, for which even a low incidence of corrosion would represent a serious economic and operational drawback. The following article is a brief review of the existing techniques for the survey and control of stray current corrosion, cathodic protection being an important method of control.

A data fusion approach to the classification of eddy current and ultrasonic measurements is proposed in a context of defect detection/recognition methods for non‐destructive testing/evaluation systems: the purpose is to demonstrate that a multi‐sensor approach that combines the advantages carried by each sensor is able to locate potential cracks on the inspected specimen. Different approaches have been compared: a pixel level data fusion approach, that distinguishes between the defect area and the no‐defect areas, by means of the information carried by the intensity of each pixel of the eddy current and ultrasonic data; a feature level data fusion approach that uses the features computed on the measured data; a symbol level data fusion approach that extracts symbols from the two sensors as complementary information and classifies the data by using these symbols. The experimental results, carried out on an aluminium plate, pointed out the ability of the symbol level proposed approach to classify the input images within a minimum overall error, by taking into account the probability of detection and the probability of false alarm for the defect.