Service Time Interval Research Articles

A novel cross-entropy-based importance sampling method for cumulative time-dependent failure probability function

Cumulative time-dependent failure probability function (C-T-FPF) can reflect the effects of distribution parameters of random inputs and the upper bound of service time interval, which vary in their design domains, on time-dependent failure probability. However, solving C-T-FPF involves a time-consuming triple-layer framework. Thus, we propose an efficient method by combining cross-entropy-based importance sampling (IS) with adaptive Kriging model (CE-IS-AK). The innovations of CE-IS-AK include two aspects. Firstly, we construct a space augmented by both distribution parameters and the upper bound of service time interval, on which the triple-layer framework is decoupled to a single-layer one. And in the augmented space, an optimal IS density is proposed to reduce the required candidate sample size for estimating C-T-FPF. Secondly, we employ Gaussian mixture model (GMM) to approximate the optimal IS density, and the parameters in GMM are determined by minimizing the cross entropy of GMM and the optimal IS density. Moreover, to reduce the model evaluations in the proposed method, Kriging model is adaptively embedded to replace the actual model, and a first failure instant based learning function is proposed to train Kriging model adaptively. Due to the proposed single-layer framework and IS strategy assisted by the Kriging model, the efficiency is greatly improved for estimating C-T-FPF, which is validated by several examples.

Integrated optimization of pilot and pilot carrier routing in seaports

Pilotage is an important service for vessels to enter and leave seaports. When vessels entering or leaving their berths, pilots are assigned to provide assistance on board to maneuver the vessels. Pilot carriers, such as pilot boats and helicopters are utilized to transport pilots from the pilot station to the vessels at appointed ground. With the increasing number of calling vessels, the pilotage plan should be made properly considering the limited pilots and carriers resources in seaports to enhance timing reliability, which is a key port performance indicator. This paper studies the pilot and pilot carrier routing problem arising in seaports, where both the routes of pilots and carriers are determined jointly to achieve the lowest pilotage costs. The required service time intervals of vessels, the synchronization between pilots and carriers and the limited working duration for both pilots and carriers are considered. The problem is formulated as an arc-flow model, and a hybrid multi-start adaptive large neighborhood search and local search algorithm (mALNS-LS) is developed. Efficient departure time and cost computation methods are designed based on a set of forward and backward functions, and a model-based post optimization is applied. Computational experiments verify the performance of the proposed mALNS-LS in terms of solution quality and efficiency.

Solving the tourist trip design problem with time windows and variable profit using incremental local search

The Team Orienteering Problem with Time Windows and Variable Profits (TOPTWVP) is a variant of the Orienteering Problem where each node has a predefined time window in which the service must start (in case this node is visited), and the vehicle may spend an amount of time given by a predefined interval so that the profit collected at this node depends on the time spent. Our previous work introduced an incremental local search procedure to solve this problem. Although the results were satisfying in terms of score, this algorithm required more time to obtain solutions due to the added complexity of working with service time intervals. To address this issue, this paper introduces several improvements to our previous implementation aimed at reducing the execution time and maintaining or increasing the quality of the solutions. Specifically, we designed a new procedure for obtaining the initial solution, which is faster and generates higher-quality solutions than the previous approach. Moreover, two new moves have been developed within the local search procedure to account for variable profits. The experiments will show that these new procedures outperform our previous implementations. Finally, we define different types of trips depending on the travel-style preferences of a tourist, and we build some scenarios to show how our TOPTWVP can be adapted to obtain routes that fulfil these preferences.

25 Interaction effects between survival outcomes of out-of-hospital cardiac arrest patients receiving intravenous fluid resuscitation and emergency medical service time interval

25 Interaction effects between survival outcomes of out-of-hospital cardiac arrest patients receiving intravenous fluid resuscitation and emergency medical service time interval

An improved multi-objective framework for the Rich arc routing problem

This article introduces a Rich Arc Routing Problem (RARP). Required arcs are partitioned into given clusters, and each cluster shall be serviced for prescribed times during the planning horizon. There is a time limit that restricts the visits that can be performed in a single day. Each vehicle has to stop at one of intermediate facilities before the end of the specific hours per day. Accordingly, several days may be necessary to complete all tasks, and paths traveled by different vehicles on the same day shall not overlap. The RARP consists of finding a set of routes with (i) the minimum total distance, (ii) the minimum number of vehicles, (iii) the minimum pure working days, and (iv) the temporal service time interval consistency of each cluster. Recently, a Local-Ideal-Points based Autonomous Space Decomposition (LIP-ASD) algorithm has been demonstrated to be a competitive multi-objective framework. However, randomly generating an initial population in each decomposed space decreases the convergence speed of LIP-ASD. In addition, retaining only one individual preserved in each sub-space limits population diversity. In response to these issues, an Improved LIP-ASD (I-LIP-ASD) for RARP is developed. The two improvements of the proposed algorithm are as follows: (i) the initial population in the current sub-space is generated by combining existing nondominated individuals, and (ii) all nondominated solutions will be output from the evolved population in each decomposed sub-space. Finally, we conduct a series of experiments over converted capacitated arc routing problem instances, as well as analyze them under a real-world case to evaluate and demonstrate the effectiveness of the proposed solution algorithm.

Increased Prehospital Emergency Medical Service Time Interval and Nontransport Rate of Patients With Fever Using Emergency Medical Services Before and After COVID-19 in Busan, Korea.

In Korea, patients with fever have been preemptively isolated to isolation beds in the emergency department (ED) since the coronavirus disease 2019 (COVID-19) pandemic began. However, isolation beds were not always available, and transport delays or failure (nontransport), especially for infants, were reported in the media. Few studies have focused on delays and failure in transporting fever patients to the ED. Therefore, this study aimed to examine and compare the emergency medical service (EMS) time interval and nontransport rate of patients with fever using EMSs before and after COVID-19. This retrospective observational study analyzed the prehospital EMS time interval and nontransport rate of fever patients who contacted EMSs in Busan, South Korea, from March 1, 2019 to February 28, 2022, using emergency dispatch reports. All fever patients (≥ 37.5°C) who contacted EMSs during this study were included. The EMS time interval was defined as the time between the patient's EMS call and ED arrival time. Nontransport was defined as a case recorded as not being transported in the emergency dispatch reports. The study population of 2019 was compared to the population of 2020 and 2021 with the independent t-test, Mann-Whitney U test, and χ² test. As a subgroup, the EMS time intervals and nontransport rates of infants with fever were compared before and after COVID-19. A total of 554,186 patients accessed the EMS during the study period, and 46,253 patients with fever were included. The EMS time interval (mean ± standard deviation, minutes) of fever patients was 30.9 ± 29.9 in 2019, 46.8 ± 127.8 in 2020 (P < 0.001) and 45.9 ± 34.0 in 2021 (P < 0.001). The nontransport rate (%) was 4.4 in 2019, 20.6 in 2020 (P < 0.001), and 19.5 in 2021 (P < 0.001). For infants with fever, the EMS time interval was 27.6 ± 10.8 in 2019, 35.1 ± 15.4 in 2020 (P < 0.001), and 42.3 ± 20.5 in 2021 (P < 0.001), and the nontransport rate (%) was 2.6 in 2019, 25.0 in 2020, and 19.7 in 2021. After the emergence of COVID-19, in Busan, the EMS time interval of fever patients was delayed, and approximately 20% of fever patients were not transported. However, infants with fever had shorter EMS time intervals and higher nontransport rates than the overall study population. A comprehensive approach, including prehospital and hospital ED flow improvements, is required beyond increasing the number of isolation beds.

An integrated queueing-inventory-routing problem in a green dual-channel supply chain considering pricing and delivery period: a case study of construction material supplier

Abstract The current paper presented a stochastic integrated queueing-inventory-routing problem into a green dual-channel supply chain considering an online retailer with a vehicle-routing problem (VRP) and a traditional retailing channel with an M/M/C queueing system. A mixed-integer non-linear programming model (MINLP) is presented to address the integrated VRP and M/M/C queueing system. The suggested model makes decisions about optimal routing, delivery time interval to customers, number of servers in traditional retailers, inventory replenishment policies, and retailers’ price. For the first time, this model considers two retailing channels simultaneously under different uncertainty, including demand, delivery lead time, service time, and delivery time interval to customers. The inventory model also follows a continuous-time Markov chain. The small-scale test problems are solved using GAMS software. Since the problem is NP-hard, this study conducts a comprehensive comparative analysis of the performance of 13 different metaheuristics. The ant lion optimiser, dragonfly algorithm, grasshopper optimisation algorithm, Harris-hawks optimisation, moth-flame optimisation algorithm, multi-verse optimizer, sine cosine algorithm, salp-swarm algorithm, the whale optimisation algorithm, grey-wolf optimiser, genetic algorithm, differential evolution, and particle swarm optimization are algorithms that were chosen for this study. Comprehensive statistical tests were conducted to evaluate the performance of these methods. Furthermore, the model is executed for construction material producers as a case study. Finally, sensitivity analyses were conducted on crucial model parameters; and managerial insights were recommended.

Emergency Medical Service Time Intervals for Patients With Suspected Stroke in the United States.

Optimal care for patients with stroke relies on timely recognition and rapid transport to appropriate treatment, often by emergency medical services (EMS). Our primary objective was to describe EMS time intervals for patients with suspected stroke in the United States. We also sought to quantify the variation in EMS time intervals by geographic location and urbanicity. We conducted a cross-sectional evaluation of EMS 9-1-1 activations (ie, calls for service) included in the 2018 and 2019 National EMS Information System datasets. We included ground or air EMS activations for a 9-1-1 scene response where a patient aged ≥18 years with suspected stroke was treated and transported by EMS. Time intervals for dispatch, response, scene, transport, and total prehospital time (ie, from dispatch to hospital arrival) were calculated, stratified by ground and air transport type. A total of 410 187 activations for suspected stroke were included, of which 98% were a ground transport. The median total prehospital time for ground transports was 35 minutes (interquartile range, 27-45, 90th percentile 58). Median total prehospital time for air transports was substantially longer at 56 minutes (interquartile range, 43-70, 90th percentile 86). Times varied by Census division and urbanicity with the shortest ground total prehospital times in the East North Central division and urban areas and longest times in the East South Central and rural and frontier areas. Timely EMS response and transport is critical for optimizing care of patients with suspected stroke. Using a large, national dataset of EMS activations, we found variations by geographic location and urbanicity in total prehospital time for ground and air EMS activations for patients with stroke.

Abstract TP47: Emergency Medical Services Time Intervals For Suspected Stroke Patients In The United States

Introduction: Prehospital recognition and rapid transport of stroke patients by emergency medical services (EMS) is critical to optimize access to time-sensitive care. We aimed to describe EMS time intervals for suspected stroke patients in the U.S. and to quantify variation in EMS time intervals by geographic location and urbanicity. Methods: We conducted a cross-sectional evaluation of EMS 9-1-1 activations (i.e., calls for service) included in the 2018 and 2019 National EMS Information System. We included ground and air EMS activations for a scene response where a patient aged ≥18 years old with suspected stroke (EMS impression of I60-I63 or G45) was treated and transported by EMS. Time intervals for dispatch, response, scene, transport, and total prehospital time were calculated, stratified by ground and air transport type. Results: A total of 415,342 activations for suspected stroke were included, of which 98% were a ground transport. The overall median total prehospital time for ground transports was 35 minutes (IQR 27-45, 90 th percentile 58; Table). Median total prehospital time for air transports was substantially longer at 56 minutes (IQR 43-70, 90 th percentile 86). Times varied by census division and urbanicity with the shortest median total prehospital time of ground transports in the East North Central division (31 min, IQR 25-40) and urban areas (34 min, IQR 27-43) and longest times in the East South Central (39 min, IQR 30-52), rural (40 min, IQR 28-56), and frontier (44 min, IQR 29-63) areas. Conclusions: With ongoing focus on optimizing time-to-treatment for acute stroke interventions, prehospital transport can be targeted for quality improvement. While some variation is expected due to geographical constraints, we found substantial variation in prehospital transport times for suspected stroke that may present opportunities for future improvement. These findings may inform health services research and policy efforts to improve stroke care access.

Abstract 10319: Community Socioeconomic and Urban-Rural Differences in Emergency Medical Services Time Intervals for Suspected Stroke Patients in North Carolina

Introduction: Rapid emergency medical services (EMS) response, care, and transport of acute stroke patients increases the likelihood of receiving time-sensitive treatment. There is limited research on the relationship of community factors with prehospital delays in EMS management of stroke. We compared EMS prehospital time intervals for suspected stroke patients by community socioeconomic status (SES) and urban-rural status in North Carolina (NC). Methods: We analyzed 2019 NC EMS encounter data collected in the National EMS Information System Version 3 standard. Eligible patients were adults requiring a 911 call response by EMS for stroke-like symptoms and transport to the hospital. Incident street addresses were geocoded to census tracts using ArcGIS Pro and linked to SES data from the American Community Survey and rural-urban commuting area (RUCA) codes. Community SES was defined as high, medium, or low based on tertiles of the AHRQ SES index. Urban, suburban, and rural tracts were defined by RUCA codes 1, 2-6, and 7-10, respectively. Differences in mean times by community SES and urban-rural status were evaluated using Kruskal Wallis tests. Results: We identified 17,117 eligible EMS encounters of suspected stroke (65% (11,121 of 17,117) 65+ years old; 55% (9,330 of 17,117) female; 70% (11,839 of 17,117) White) from 2,028 tracts. Median response, scene, and transport times were 8 (interquartile range, IQR 6-11) min, 16 (IQR 12-20) min, and 14 (IQR 9-22) min, respectively. Mean transport times were shorter in low SES (16 min) than in medium and high SES communities (17 min, p&lt;.0001). Mean transport times were longer in rural (21 min) and suburban (19 min) than in urban tracts (14 min, p&lt;.0001). Conclusions: EMS transport times were on average longer for suspected stroke patients in rural but not in low SES tracts. Further research is needed on the role of community socioeconomic deprivation and rurality in contributing to delays in prehospital stroke care.

Adaptive Kriging Model for Fuzzy Safety Degree Analysis to Time-Dependent Structure

Time-dependent failure possibility (TDFP) has the capability to measure the safety degree of a structure under fuzzy uncertainty over a service time interval of interest. To improve the computational efficiency in estimating TDFP, an adaptive kriging model is developed in this paper. In the proposed method, TDFP is first represented as a bilevel problem, where the outer level is a one-dimensional rooting problem with respect to the membership level of fuzzy variables and the inner level is a minimum optimization of the model response function where the interval parameters and time are regarded as the same level. Second, the dichotomy instead of the interpolation technique is employed to solve the one-dimensional rooting problem. Third, the numerical simulation replacing the optimization technique is used to settle the optimization problem. Finally, to greatly reduce the computational cost in estimating the TDFP especially involved in numerical simulations, an adaptive kriging model is proposed for TDFP analysis. Additionally, the proposed kriging model can be used to estimate the safety life based on the TDFP constraint. The results of a mathematical example and two aerospace engineering examples show that the proposed method significantly improves the efficiency in estimating the TDFP and the TDFP-based safety life with acceptable precision.

Comparison of pre-hospital emergency services time intervals in patients with heart attack in Arak, Iran.

:Background:After cardiac arrest, the possibility of death or irreversible complications will highly increase in the absence of cardiac resuscitation within 4 to 6 minutes. Accordingly, measuring the pre-hospital services time intervals is important for better management of emergency medical services delivery. The purpose of this study then was to investigate pre-hospital time intervals for patients with heart attack in Arak city, based on locations and time variables.Methods:This is a retrospective descriptive cross-sectional study, which was conducted at the Arak Emergency Medical Services (EMS) during 2017-2018. Data were analyzed by SPSS version 13.Results:The total number of heart attack patients registered in Arak emergency medical services was 2,659 of which 51% of patients were males. Six percent of patients were under 25 and about 49 percent were between 46 and 65 years old. The average of activation, response, on-scene, transportation, recovery and total time intervals were 3:30, 7:56, 15:15, 13:34, 11:07, 12:11, and 41:25, respectively. In the city area, the shortest and longest average response time intervals were in spring and winter, respectively. In out of the city area, the shortest average response time interval was in summer and the longest one in autumn. The shortest and the longest average response time intervals in the city area were in June and March, respectively, and in out of the city area, the shortest average response time interval was in June and the longest one in April.Conclusions:The shorter response and delivery time interval compared to the other studies may indicate improvement in the provision of EMS. Special attention should be paid to the facilities and equipment of vehicles during cold seasons to be in the shortest possible time. Also, training and informing the staff more about the code of cardiac patients along with general public education can help improve these intervals.

The association between time intervals in emergency medical services and In-hospital mortality of trauma patients

Context: While the clinical practice recommends field stabilization in trauma patients, in some situations, the speed of transport is crucial. Aims: This study aimed to evaluate the association between emergency medical services (EMS) time intervals (response time [RT], scene time [ST], and transport time [TT]) and in-hospital mortality in trauma patients in Tehran, the largest metropolis of Iran. Settings and Design: A prospective cohort study was conducted between May 2017 and April 2018. Methods: All EMS operations related to trauma events in the Tehran city that were transferred to three targeted major trauma centers were included. Statistical Analysis: Logistic regression analysis was used to assess the relationship between EMS time intervals and other risk factors of trauma death. Results: A total of 14,372 trauma patients were included in the final analysis. In-hospital mortality occurred in 225 (1.6%) patients. After adjustment for confounding variables, older age (odds ratio [OR] = 1.04/year), female gender (OR = 2.16), low Mechanism, Glasgow Coma Scale (GCS), age, and arterial pressure score (OR = 0.84 for each unit), low GCS (OR = 0.56 for each unit), longer ST (OR = 1.17/10 min), and longer TT (OR = 1.21/10 min) were found to be risk factors for death in trauma. Conclusions: Our study showed that in-hospital mortality of trauma patients correlated with longer EMS ST and TT, but the RT was not associated with mortality. Our results recommend that the EMS system should consider ST and TT rather than RT, as indexes of quality control in prehospital care of trauma patients.

СРЕДНЯЯ ДЛИНА ОЧЕРЕДИ ДЛЯ СИСТЕМ МАССОВОГО ОБСЛУЖИВАНИЯ С КОРРЕЛИРОВАННЫМИ ВХОДНЫМИ ПОТОКАМИ

In multiservice packet-switched networks, the packet flow differs significantly from the Poisson flow, since these flows are generated by many sources of requests for services that are significantly different from each other. All this leads to the fact that the flows in multiservice networks are characterized by uneven arrival of requests and packets. Packages are grouped into "bundles" at some time intervals and are practically absent at other intervals. The random process of claims (packets) entering the system is characterized by a distribution law that establishes a relationship between the values ??of a random variable and the probabilities of occurrence of the indicated values. In most cases, such a flow is characterized by a distribution function of time intervals between neighboring claims, and the process of their processing is characterized by a probability distribution function of service time intervals. The mathematical model of the simplest single-channel queuing systems (QS) in case of incoming flow with arbitrary correlation. For this QS, various generalizations of the Khinchin-Pollachek formula of the average queue length. An interval model of the incoming flow is proposed, within which an expression of the average queue length through unconditional moments is obtained second order. All results were obtained with very general assumptions of ergodicity and stationarity. Are given results of numerical experiments confirming theoretical conclusions.

Emergency Medical Services Time Intervals for Acute Chest Pain in the United States, 2015–2016

Background: Chest pain is a leading complaint in emergency settings. Timely emergency medical services (EMS) responses can reduce delays to treatment and improve clinical outcomes for acute myocardial infarction patients and other medical emergencies. We investigated national-level EMS response, scene, and transport times for acute chest pain patients in the United States. Methods: A retrospective analysis was performed using 2015–2016 data from the National EMS Information System (NEMSIS). Eligible patients were identified as having a provider impression of chest pain or discomfort and not due to trauma or resulting in cardiac arrest during EMS care. Descriptive analyses of prehospital time intervals and patient-, response-, and system-level covariates were performed. Multivariable logistic regression was used to measure associations between meeting response and scene time benchmarks (8-min and 15-min, respectively) and covariates. Results: Our study identified 1,672,893 eligible EMS encounters of chest pain. Patients had a mean age of 63.1 years (SD = 14.8). The population was evenly distributed by sex (51% male; 49% female). Most encounters occurred in home or residence (58%) and had lights and sirens response to scene (84%). Most encounters were in urban areas (78%). The median (interquartile range, IQR) response time was 7 (5–10) minutes. The median (IQR) scene time was 16 (12–20) minutes. The median (IQR) transport time was 13 (8–20) minutes. Generally, median response and transport times were longer in rural and frontier areas compared to urban and suburban areas. Only 65% and 49% met the 8-min response and 15-min scene time benchmarks. Responding with lights and sirens was associated with greater compliance with EMS response time benchmark. EMS care of older age groups and females was less likely to meet the scene time benchmark. Conclusions: Substantial proportions of EMS encounters for chest pain did not meet response and scene time benchmarks. Regional and urban-rural differences were observed in adherence with the response time benchmark. Our findings also suggest age and gender disparities in on-scene delays by EMS. Our study contributes important evidence on timely EMS responses for cardiac chest pain and provides suggestions for EMS system benchmarking and quality improvement.

The Effect of All-Terrain Vehicle Crash Location on Emergency Medical Services Time Intervals

Over 100,000 all-terrain vehicle (ATV)-related injuries are evaluated in U.S. emergency departments each year. In this study, we analyzed the time intervals for emergency medical services (EMS) providers responding to ATV crashes in different location types. Data from the Iowa State Trauma Registry and a statewide ATV crash/injury database was matched with Iowa EMS Registry records from 2004–2014. Ground ambulance responses to 270 ATV crashes were identified, and response characteristics and time intervals were analyzed. Off-road crashes had a longer median patient access interval (p &lt; 0.001) and total on scene interval (p = 0.002) than roadway crashes. Crashes in remote locations had a longer median patient access interval (p &lt; 0.001) and total on scene interval (p &lt; 0.001), but also a longer median on scene with patient interval (p = 0.004) than crashes in accessible locations. Fifteen percent of remote patient access times were &gt;6 min as compared to 3% of accessible crashes (p = 0.0004). There were no differences in en route to scene or en route to hospital time. Comparisons by location type showed no differences in injury severity score or number of total procedures performed. We concluded that responding EMS providers had an increased length of time to get to the patient after arriving on scene for off-road and remote ATV crashes relative to roadway and accessible location crashes, respectively.

Time-dependent reliability analysis model under fuzzy state and its safety lifetime model

In view of the lack of time-dependent reliability analysis model (TDRA) under fuzzy state, which is ubiquitous in engineering, a TDRA model under fuzzy state is proposed in this paper, followed by the corresponding safety lifetime model. To establish the TDRA model under fuzzy state, this paper firstly transforms the TDRA model under binary state into a form expressed by the time-dependent failure domain indicator function, and then the TDRA model under fuzzy state is derived based on the basic principle of the time-independent reliability analysis (TIRA) model under fuzzy state. By introducing an auxiliary variable and establishing the time-dependent generalized performance function, the TDRA model under fuzzy state is transformed into a generalized one under binary state, where the failure domain and safety domain are clearly defined. Then, the single-loop Kriging (SLK) surrogate model approach is used to efficiently estimate the time-dependent failure probability (TDFP) in the special service time interval under fuzzy state. Based on the generalized TDRA model and its efficient estimation, a safety lifetime model constrained by the target TDFP under fuzzy state and a corresponding efficient solving method are presented. Finally, examples are used to verify the rationality of the TDRA model and the safety lifetime model under fuzzy state established in this paper, and the efficiency of the algorithm is also validated.

THE USE OF WIND-HYDROGEN UNINTERRUPTED POWER SUPPLY PLANT IN DIFFERENT CLIMATIC CONDITIONS

The paper presents the project of the autonomous power complex on the basis of wind-power plant and hydrogen module with a capacity in 3 kW with further replication to 50 kW and shows the possibilities of operation of the present plant in different climatic conditions of Russia: Siberia, the Far East, the Northern Caucasus, Krasnodar territory, and also for universal use in climatic zones of the Arctic and Antarctic, deserts of Africa and the isolated islands with typical destructive sea salt fogs.This paper carries out the study, comprehensive analysis and comparison of known types and classes of wind plants, as a result of which the authors have developed an innovative multi-tier scalable vertically-axial wind power plant. This unit is used as the main power source, the uninterrupted part of which is based on a cyclically operating hydrogen module, contains an electrolytic cell, a fuel cell system and a hydrogen storage device with a communication and control system. The components of the power plant developed by the authors’ team operate at a single DC voltage and can be connected to a common bus bar with an increase of power in this complex. Flexible control algorithms allow optimizing the operation of the power complex to reduce the start-stop frequency, thereby increasing both the service life and time intervals between maintenance. Remote control provides monitoring and management of electricity output processes and hydrogen storage with the help of Internet technologies in long-term modes.The study has shown that this equipment is long-lived, reliable and environmentally friendly, and the system is modular and flexible because it is easily scaled under consumer’s control including the personal power consumption and small business. Moreover, the developed power plant is accessible in purchase, mounting and operation for remote energy consumers as far as the assessed value of equipment is correlating with the cost of power line installation and the operation of equipment does not require large engineering and technological skills.

The experimental measurement of the tyre casing defects for the freight vehicles at the dynamic loading

The paper deals with the experimental measurement of the tyre casing defects for the freight vehicles at the dynamic loading. The given investigation was mainly focused on cracks and defects in tyre casing, which is commonly used for freight vehicles. The mentioned measurement or investigation was performed under the strictly specified conditions. The given measurement of crack propagation in car tyre casing was based on changes of speed, changes of loading as well as changes of service time interval. It is important to point out that the pressure in the tyre was predetermined to be the constant value. The experimental procedures were carried out by help of special drum testing machine with designation: IGTT 25 kN – C and with the 1707 mm drum diameter. The mentioned measurement was performed for the area of tyre casing shoulder and it was in the site between the first and the second buffer lining. Using the ITT-1 program relating to non-destructive testing analyser, the CCD camera for testing procedure of tyre casing was used for the camera images which were taken from the internal side of the tyre casing.

Application of spherical indentation and the materials knowledge system framework to establishing microstructure-yield strength linkages from carbon steel scoops excised from high-temperature exposed components

Industrial power generation turbines operate at elevated temperatures for prolonged periods of time (around 100,000 h) which leads to significant microstructure evolution and mechanical property changes. Due to physical and structural constraints of operational turbines, only small scoop samples can be excised from heat-exposed steel components. Scoop samples at various service time intervals provide valuable information on microstructure changes, for example on graphite formation in carbon steels, with increasing service time. However, mechanical evaluation of such small material volumes poses significant challenges using conventional tests. A novel spherical microindentation technique is applied to evaluate a library of scoop samples ranging between 0 and 99,000 h of service. Furthermore, microstructure and yield strength data for the different exposure periods is used to construct a structure-property (S-P) linkage using the MKS homogenization approach that employs spatial correlations, principal component analysis, and regression techniques. The accuracy of the extracted S-P linkage was assessed on new samples that were not included in the calibration set.