Unit Load Research Articles

Design and Experimental Validation of a Scaled Test Bench for the Emulation of a Hybrid Fuel Cell Powertrain for Agricultural Tractors

Hybrid fuel cell powertrains are a promising strategy to reduce the environmental impact of vehicles and non-road mobile machinery. To preserve the state-of-health of fuel cells, an energy storage system with sufficient power capacity, such as ultra-capacitors or batteries, should be introduced in the system to help the fuel cell during sudden and abrupt changes in power demands. However, the presence of two or more energy sources necessitates the development of an energy management strategy. The energy management strategy should properly split the power request between the different energy sources. In this paper, the design and the experimental validation of a scaled test bench for the emulation of a fuel cell/battery powertrain for a vehicular application is presented. The fuel cell is emulated through an analogically controlled DC power source that reproduces its real voltage–current curve. To split the power between the emulated fuel cell and the batteries, controlled DC-DC is used and a simple energy management strategy based on a proportional-integral controller is developed. The external load is reproduced using a load unit composed of a programmable electronic load and a power supply. Experimental tests are performed to evaluate the system behaviour and to characterize its main components. The experimental results show that the system successfully emulates the powertrain in accordance with the proposed energy management strategy.

A tractor hydraulic assisted embedded microprocessor-based penetrometer for soil compaction measurement

Measurement of soil compaction in terms of penetration resistance using a hand penetrometer requires more time and effort. A tractor hydraulic-assisted embedded microprocessor-based penetrometer was developed to make the results easy to monitor and decrease human error. The developed penetrometer consisted of a driving system for pushing the penetrometer probe into the soil at a desired speed, a sensor unit (load cell and ultrasonic sensor) for measuring the force required to push the probe and the depth of penetration, and a data logging system. The embedded system of the penetrometer comprised various components: Arduino Uno microcontroller, I2C, WiFi module, and HX711 amplifier. The system was able to measure a soil penetration resistance of 5000 kPa up to a depth of 500 mm. A WiFi module helped to transmit the data to an Android mobile application. The acquired data also include date/time parameters along with latitude and longitude locations picked up from the GPS of the mobile. Its performance was assessed based on sensor characteristics such as accuracy, sensitivity, non-linearity, and non-repeatability. The average and maximum absolute variations in the cone index values measured with developed system and a hand-held digital penetrometer were observed to be 22.50% and 27.88%, respectively.

Optimization of the Load of Production Units of the Construction Company

The aim of the work is to develop a methodology for optimizing the work schedule under the production program of the construction company. The sample was selected based on deterministic mathematical methods and modelling. In particular, the method of processing expert opinions (method of expert evaluation) is used in this study to assess the actual degree of influence of each of the factors and its group on production indicators of the construction company. Methods of organizational and technological modelling, elements of systems theory, elements of systematics, construction system engineering were also used. A method of building and optimizing the work schedule under the production program of the construction company was developed during this study. This was implemented based on the concentration and regulation of labor resources of production units at dispersed start-up complex, as well as the maximum use of internal reserves of production units. This technique ensures the development of typical optimization solutions aimed at balanced resource consumption and effective fulfillment of the terms of construction contracts. Prospects for further research are based on the development of software in compliance with the presented methodology.

Multi-objective Optimal Scheduling Analysis of Power System Based on Improved Particle Swarm Algorithm

Economic Environmental Dispatching (EED) in power systems is a multi-variable, strongly constrained, non-convex, multi-objective optimization problem that is difficult to properly handle using traditional methods. However, the application of particle swarm optimization algorithms may result in insufficient population diversity and easy to fall into local optimization problems. Therefore, this paper proposes an adaptive backbone multi-objective particle swarm optimization (ABBMOPSO) method to solve the economic and environmental scheduling problems of power systems. This paper first analyzes the topology and computational flow of particle swarm optimization algorithms, and then constructs a multi-objective optimization research framework that integrates Pareto optimization principles for the scheduling of power generation units. The execution algorithm is the improved multi-objective particle swarm optimization algorithm (MOPSO). This paper establishes a mathematical model for the economic and environmental scheduling of power systems, which optimizes conflicting fuel cost functions and pollutant emission functions simultaneously, taking into account nonlinear constraints such as load balance constraints and unit operation constraints. The improved ABBMOPSO algorithm is used to optimize the solution to improve the global search ability of the EED model. The simulation data of seven units show that the ABBMOPSO algorithm has a minimum power generation cost of 588.1 $/h and a minimum pollutant emission of 0.192 t/h, which is significantly superior to other algorithms and reduces the number of iterations, with good feasibility.

A Homotopy-Based Approach to Solve the Power Flow Problem in Islanded Microgrid with Droop-Controlled Distributed Generation Units

This paper proposes a homotopy-based approach to solve the power flow problem (PFP) in islanded microgrid networks with droop-controlled distributed generation (DG) units. The technique is based on modifying an “easy” problem solution that evolves with the computation of intermediate results to the PFP solution of interest. These intermediate results require the solution of nonlinear equations through Newton–Raphson (NR) method. In favor of convergence, the intermediate solutions are close to each other, strengthening the convergence qualities of the technique for the solution of interest. The DG units are modeled with operational power limits and three types of droop-control strategies, while the loads are both magnitude voltage- and frequency-dependent. To evaluate the method performance, simulations are performed considering the proposed and classical NR methods, both departing from a flat start estimation. Tests are carried out in three test systems. Different load and DG unit scenarios are implemented for a 6-, 38-, and 69-bus test system. A base case is studied for all systems, while for the two larger models, a loading factor is used to simulate the load augmenting up to the maximum value. The results demonstrated that for the largest-size model system, only the homotopy-based approach could solve the PFP for stringent requirements such as the diversification of the load profile and hard loading operation point.

Improvement of MBBR Performance by the Addition of 3D-Printed Biocarriers Fabricated with 13X and Bentonite

The current study investigated the performance of a moving bed biofilm reactor (MBBR), when adding 3D-printed biocarriers fabricated with 13X and bentonite (MBBR 3D), when using K1 commercial biocarriers (MBBR K1) and when not adding biocarriers at all (control MBBR). For the evaluation of the MBBR efficiency, various physicochemical parameters were measured, while biofilm extracted from the biocarriers was evaluated. The findings suggest that there is an optimal biodegradation of the organic load in all MBBR units. The nitrification and denitrification processes were improved in MBBR 3D as compared to the control MBBR and MBBR K1. The dry mass of the biofilm in the 3D-printed biocarriers was two orders of magnitude larger than in the K1 biocarriers. Moreover, in the K1 biocarriers the mass of the biofilm varied in relation to time, since it could not be protected inside the holes, something that did not happen with the 3D-printed biocarriers. Finally, it was found, mostly in MBBR 3D and less in MBBR K1, that the growth of nitrifying bacteria and heterotrophs inside the units increased the biomass production in the form of soluble microbial products, which in turn favored the adhesion of biomass on the surface of biocarriers.

Chitosan/poly (ethylene oxide) nanofiber sponge with dual-responsive drug release and excellent antibacterial property

An ideal wound dressing can absorb wound exudate in time, and has the advantages of moisture permeability, oxygen permeability, rapid hemostatic performance, antibacterial and low-toxic, which are the key to wound healing. However, traditional wound dressings exist structural and functional defects, especially in controlling bleeding and active wound protection. Herein, a novel three-dimensional chitosan/ poly (ethylene oxide) sponge dressing (3D CS/PEO sponge-ZPC) consists of CS/PEO nanofiber sponge (carrier unit), Zn metal-organic framework grown in-situ (Zn-MOF, drug loading unit and antibacterial unit), curcumin (CUR, antibacterial unit), and poly[(N-isopropylacrylamide)-co-(methacrylic acid)] (P(NIPAM-co-MAA), ‘gatekeepers’ unit) to promote the wound healing by absorb exudate in time, accelerate hemostasis and inhibit bacteria growth. Due to the unique structure of the as-prepared 3D CS/PEO sponge-ZPC was endowed with smart stimuli-responsive drug release mode, rapid hemostatic performance and strong antibacterial property. The result of CUR release showed smart “ON-OFF” drug release mode. Antibacterial results verified strong antibacterial property up to 99.9 %. Hemolysis test showed that hemolysis ratio of 3D CS/PEO sponge-ZPC met the acceptable standard. The rapid hemostatic property was demonstrated by hemostatic test. High wound healing effect was confirmed in vivo. These results provide an important research basis for the design of new smart dressing.

The response of non-point source pollution to land use change and risk assessment based on model simulation and grey water footprint theory in an agricultural river basin of Yangtze River, China

Non-point source (NPS) pollution has gradually become the main source of water environmental pollution with the rapid economic development during the recent decades, especially for the economically developed Yangtze River Basin of China. Due to rapid urbanization, the pressure of the water environment in the Poyang Lake basin (PYLB) has been increasing. In this study, the spatial and temporal variations of NPS pollution loads including total nitrogen (TN) and total phosphorus (TP) in the PYLB during the period 2003–2012 were firstly investigated by using the SWAT; then the changes in NPS pollution loads under different land use types were identified by using the SWAT, land use transition matrix, statistical analysis and scenario analysis methods; finally, the NPS pollution risk assessment were achieved by means of the grey water footprint theory. The results showed that the NPS pollution loads in the PYLB were concentrated from April to June with a large inter-annual variability. The Gan River basin contributed the largest proportion of pollutants entering into the Poyang lake while the Xiu River basin produced the smallest pollution loads. Under the background of the policy of “Grain for Green Project” since 2002, the areas of cultivated land, grassland and bare land decreased during the period 2000–2010, while those of forest land and settlement increased. As the main source of NPS pollution, the area of cultivated land has decreased, while the unit load intensity under cultivated land has significantly increased. By calculating the annual GWF of TN and TP loads and their corresponding WPL, which all showed an upward trend. The results obtained in this study have practical significance for reducing the NPS pollution loads in the PYLB and controlling the environmental pollution in the Yangtze River.

Impact of Dry Port on Seaport Competitiveness

Ports play an important role in connecting individuals in need of logistics services with organizations that provide logistics services. Rather of being merely transshipment hubs. Ports have recently evolved into integrated logistics centers with a continuous transport chain, with these developments primarily relying on the supply chain systems of major port operators. Though changes impact terminal handling traffic, rising quantities have increased job pressure, as well as congestion levels and dwell periods in terminal areas. The dry port model relies on a seaport which is directly connected to inland intermodal stations, where freight may be rotated immediately to the seaport in intermodal loading units. This research investigates the influence of vessel growth on port competitiveness and investigates integration between seaports and dry ports to counteract the huge increase in ship size at seaports. To achieve this goal, a survey was conducted to measure the relationship between dry ports and seaports. This paper also illustrates how the vessel expansion is associated with reduced operational efficiency, congestion, limited capacity and infrastructure support, outdated guidelines for existing port development, and the urgent need for additional investment in spatial development, and human resource development.

Impact of Dry Port on Seaport Competitiveness

Ports play an important role in connecting individuals in need of logistics services with organizations that provide logistics services. Rather of being merely transshipment hubs. Ports have recently evolved into integrated logistics centers with a continuous transport chain, with these developments primarily relying on the supply chain systems of major port operators. Though changes impact terminal handling traffic, rising quantities have increased job pressure, as well as congestion levels and dwell periods in terminal areas. The dry port model relies on a seaport which is directly connected to inland intermodal stations, where freight may be rotated immediately to the seaport in intermodal loading units. This research investigates the influence of vessel growth on port competitiveness and investigates integration between seaports and dry ports to counteract the huge increase in ship size at seaports. To achieve this goal, a survey was conducted to measure the relationship between dry ports and seaports. This paper also illustrates how the vessel expansion is associated with reduced operational efficiency, congestion, limited capacity and infrastructure support, outdated guidelines for existing port development, and the urgent need for additional investment in spatial development, and human resource development. Keywords: Dry Ports – Competitiveness – Seaports – Vessel size

ИССЛЕДОВАНИЕ ОСОБЕННОСТЕЙ ИСПОЛЬЗОВАНИЯ НОРМАЛИЗОВАННОЙ ТЕПЛОВОЙ НАГРУЗКИ ДЛЯ ОПРЕДЕЛЕНИЯ УРОВНЯ ЭНЕРГОЭФФЕТКИВНОСТИ КОТЕЛЬНОГО АГРЕГАТА В КОНКРЕТНЫХ УСЛОВИЯХ

When comparing the efficiency gross of the same units operating under different conditions, or the same unit for different periods of time, often does not take into account that these values are obtained under different conditions. It is well known that the efficiency of the boiler unit depends on the heat load of the boiler. As a rule, the value of efficiency maximum at moderate loads of the boiler unit and then with increasing heat load gradually decreases according to a law close to linear. Thus, it is possible that for a unit with a better technical condition, an efficiency value will be obtained that is lower than that of another unit operating in more favorable conditions. There is also ambiguity in the presentation of the efficiency dependence. boiler unit from heat load. The paper studies the issue of the features of using the normalized heat load to determine the level of energy efficiency of a boiler unit based on the TVG-4r boiler of a small quarterly boiler house. It is shown that a feature of using the reduced efficiency, which is determined depending on the normalized heat load, is that this indicator characterizes not only the actual technical condition of the boiler unit, but also the efficiency of its regulation, taking into account changes outside air temperature

Evaluation of microbiological contamination in the dental services of the ministry of public health of the city of Cuenca-Ecuador

Introduction: The control of microorganisms present on the surfaces of the dental environment is a critical factor. Contamination from these pathogens can occur through direct or indirect contact between surfaces and clinical staff. Stopping cross infection in dental offices represents a great challenge for dentists and microbiologists. Objective: To compare the bacterial load of the dental units of the centers of the Ministry of Public Health, after the disinfection process, in the interval of attention from one patient to another; in the city of Cuenca, Ecuador. Materials and methods: It is a cross-sectional analytical observational study, which analyzes 12 surfaces from 3 centers of the Ministry of Public Health (MSP) in the city of Cuenca-Ecuador, selected at random. Results: Samples were isolated on 4 surfaces, each from 3 health centers; where 4 microorganisms were identified among them: Streptococcus viridans, Bacillus Subtilis, Yeasts and Staphylococcus coagulase negative, where the most prevalent was Bacillus subtilis. Conclusion: The cleaning protocols are deficient; it is recommended to carry out periodic controls on the quality of disinfection in public dental health care centers.

Comparative analysis of the USA's Washington Ferries and road transport carbon emissions using the Trozzi and Vaccaro and Greatest Integer functions.

Countries' sectors are currently under great scrutiny for their response to the greenhouse gas (GHG) emission profile and the general effect of the sectoral activities on the environment. As in the agenda of all sectors, environmental concerns and investigations are of high importance in shipping and maritime transport. Amidst the rising forms of globalization, the need for sustainable transportation is constantly increasing. However, the machines that are the cornerstone of transportation largely depend on fossil fuels, thus resulting in environmental degradation. Notably, environmental-related degradation has continued to account for global warming, climate change, and ocean acidification. Shipping is considered the most environmentally friendly mode of transportation in terms of carbon dioxide (CO2) emissions per ton per mile of transported unit load when compared against road transportation. In this study, six ferry lines (FLs) of Washington State Ferries were calculated to compare ship-generated carbon dioxide (CO2) emissions with those from road transportation as if the carried vehicles had used the highway instead of transport by FL. While making these calculations, the Greatest Integer function (GIF) and Trozzi and Vaccaro function (TVF) were utilized. From the examined three scenarios, i.e., all passengers travel by car instead of ferry as scenario 1, all ferries carry both cars and passengers as scenario 2, and all car-free passengers travel by bus instead of ferry as scenario 3, the outlined results are as follows: (i) none of the cars were carried by the ferry, and car-free passengers preferred traveling by their own cars as observed in scenario 1; (ii) hypothetical scenarios (1 to 3) in which the road vehicles carried on FLs had instead used the highway, and the total potential CO2 emissions of these road vehicles were calculated as 2,638,858.138, 704,958.2998, and 1,394,148.577 tonnes per year, respectively. Policy-wise, this study revealed the management strategies for CO2 emissions reduction for two transport modes, shipping and road transportation, under current conditions.

Degradation of sulfamethoxazole and antibiotic resistance genes from surface water in the photocatalyst-loading bionic ecosystems

The behavior and removal of sulfamethoxazole (SMX) and 3 typical corresponding antibiotic resistance genes (ARGs) including sul1, sul2, sul3, and 16S rDNA in surface water were investigated in the photocatalyst-loading bionic ecosystems (PCBEs). Synthesized composite photocatalyst g-C3N4/TiO2 showing higher catalytic activity than Fe/g-C3N4/TiO2 was selected in the PCBEs. Five PCBEs, i.e., A-the control (without bionic grass or photocatalyst), B-bionic grass loaded with 4.12 g/m2 g-C3N4/TiO2, C-bionic grass loaded with 8.25 g/m2 g-C3N4/TiO2, D-bionic grass loaded with 12.37 g/m2 g-C3N4/TiO2, and E-bionic grass loaded with 16.5 g/m2 g-C3N4/TiO2 were constructed and operated in a medium-scale running cyclical flume. SMX could be photolyzed efficiently by g-C3N4/TiO2 with an optimal unit load on the bionic grass of 12.37 g/m2. 3-amino-5-methylisooxazole and p-aminobenzene sulfonamide were selected as main intermediates through the analyses of SMX degradation mechanisms and pathways, and detected in the aqueous phase and bionic grass. The intermediates were higher in the underwater part of the bionic grass than the above-water part. The overall removal of SMX ranged from 31.7 % to 82.3 % in 5 PCBEs, and the removal of sul1and sul2 were 0.2 %- 62.9 % in the aqueous phase and 8.4 %–63.2 % in the sediment. PCBE D might be the best construction when SMX and ARGs' removal was considered comprehensively. Moreover, the microbial structures showed Proteobacteria as the most dominant bacterial species had a relative abundance of 22.2 %–26.6 % and 33.4 %–68.2 % in the aquatic phase and sediment respectively, illustrating that the removal of the antibiotic and ARGs was bound up with the variations of dominant bacteria in the ecosystems. The findings illustrated that ecosystems with bionic grass and photocatalysts could be a promising technology for the removal of typical antibiotics and ARGs from surface water.

A Combinatorial Optimization Approach for Air Cargo Palletization and Aircraft Loading

The current air cargo loading plan handles the Air Cargo Palletization Problem (ACPP) and the Aircraft Weight and Balance Problem (WBP) separately, which has an impact on the optimization of the payload and the aircraft’s center of gravity (CG). Thanks to improvements in computer processing power, the joint combinatorial optimization of ACPP and WBP is now feasible. Three integer linear programming models are proposed: a Bi-objective Optimization Model (BOM), a Combinatorial Optimization Model (COM), and an Improved Combinatorial Optimization Model (IOM). The objectives of the models are the maximum loading capacity and the lowest CG deviation from a specified target CG. The models also consider a wide range of restrictions in the actual packing and stowage procedures, such as volume, weight, loading position, aircraft balance, and other aspects of aircraft and unit load devices. Four scenarios with various conditional metrics for three models are solved for the B777F aircraft using Gurobi. The results of the computations demonstrate that the BOM has the fastest solution speed, but the CG deviation is the largest, and in several cases the CG deviation results are unacceptable. The COM has the longest solution time, which is difficult to tolerate in practice. Despite taking a little longer to solve computationally than the BOM, the IOM offers the best optimization solution.

Diffuse pollutant load predictions in areas that implement the total maximum daily load due to climate change

Total maximum daily load (TMDL), which is implemented for water quality management in a watershed, necessitates the use of a watershed model to predict the load. However, such a model consumes a lot of time and effort until the results are simulated. Therefore, the present study aimed to compare and evaluate load changes following the revision of the land-based diffuse pollutant unit load values, which are used to calculate the diffuse pollutant discharge loads in the total maximum daily load (TMDL) guidelines established for TMDL control by watersheds in South Korea, using the Natural Resources Conservation Service (NRCS) method. When the revised unit load was used, the loads were reduced by an average of 56.8% compared with the prior unit load. The descending order of load change rate was biochemical oxygen demand (BOD) > total phosphorus (TP) > total nitrogen (TN). Although the difference in load discharge trends between the Representative Concentration Pathway (RCP) 2.6 and RCP8.5 scenarios was insignificant, the load discharge under the worst scenario (RCP8.5) may increase. When the future period was split into 30-year increments, the load of precipitation and diffuse pollutants increased in the intermediate future (2041–2070). This study examined how the management ratio of diffuse pollutants in a watershed changes when the legal standard value of institutionally managed diffuse pollutants changes. The findings of this study provide useful information for the efficient management of present and future diffuse pollutants.

Study on the Effects of Wet Flue Gas Desulfurization on Particulate Matter Emission from Industrial Coal-Fired Power Plants

This study aimed to investigate the effects of wet flue gas desulfurization (WFGD) on particulate matter (PM) emissions in coal-fired power plants (CFPPs) using an electrical low-pressure impactor (ELPI). The investigation was conducted on five industrial CFPPs of various loads in China to clarify the influence factors of WFGD on PM10 emissions. After WFGD, the proportion of PM2.5 to PM10 in the outlet flue gas increases, which showed that the WFGD system is selective in the capture of PM, with a significant effect on the capture of large particle sizes. The investigation found that four spray layers have a better effect on the capture of particles than two spray layers. Additionally, the investigation also found that unit load is not the main factor affecting the efficiency of PM10 capture by WFGD. Instead, the factors affecting the capture efficiency of PM10 by WFGD are the inlet flue gas temperature and the dust concentration. Relatively higher inlet flue gas temperature and lower inlet dust concentration will both result in higher emission of PM0.1~1 from the WFGD outlet. These findings suggest that a matched integration of WFGD and CFPP is essential for ultra-low PM emission control and green industry development.

Identifying critical regions for nitrogen and phosphorus loss management in a large-scale complex basin: The Jialing River

The determination of critical management areas for nitrogen (N) and phosphorus (P) losses in large-scale basins is critical to reduce costs and improve efficiency. In this study, the spatial and temporal characteristics of the N and P losses in the Jialing River from 2000 to 2019 were calculated based on the Soil and Water Assessment Tool (SWAT) model. The trends were analyzed using the Theil-Sen median analysis and Mann–Kendall test. The Getis-Ord Gi* was used to determine significant coldspot and hotspot regions to identify critical regions and priorities for regional management. The ranges of the annual average unit load losses for N and P in the Jialing River were 1.21–54.53 kg ha−1 and 0.05–1.35 kg ha−1, respectively. The interannual variations in both N and P losses showed decreasing trends, with change rates of 0.327 and 0.003 kg ha−1·a−1 and change magnitudes of 50.96% and 41.05%, respectively. N and P losses were highest in the summer and lowest in the winter. The coldspot regions for N loss were clustered northwest of the upstream Jialing River and north of Fujiang River. The coldspot regions for P loss were clustered in the central, western, and northern areas of the upstream Jialing River. The above regions were found to be not critical for management. The hotspot regions for N loss were clustered in the south of the upstream Jialing River, the central-western and southern areas of the Fujiang River, and the central area of the Qujiang River. The hotspot regions for P loss were clustered in the south-central area of the upstream Jialing River, the southern and northern areas of the middle and downstream Jialing River, the western and southern areas of the Fujiang River, and the southern area of the Qujiang River. The above regions were found to be critical for management. There was a significant difference between the high load area for N and the hotspot regions, while the high load region for P was consistent with the hotspot regions. The coldspot and hotspot regions for N would change locally in spring and winter, and the coldspot and hotspot regions for P would change locally in summer and winter, respectively. Therefore, managers should make specific adjustments in critical regions for different pollutants according to seasonal characteristics when developing management programs.

Automation in cargo loading/unloading processes: do unmanned loading technologies bring benefits when both purchase and operational cost are considered?

The use of technologies that automate handling goods and loading units in warehouses and depots is not new. Yet, the purchase process of these technologies issues troubles and the estimation of the economic advantages brought by one or another technology to the entire chain of operations in logistics are not always known. Faults or not documented decisions put pressure on managers and prices for services. They can cause a drop in the competitiveness of warehouse operators, particularly in uncertain conditions. Academia documented the cost of warehouse storage well. Yet, little research has looked into the economic justification of implementing automatic systems for loading or unloading activities and the impact on complementary operations. For this reason, a model is needed to calculate the cost of operations when different technical equipment is used. This research further investigates the cost categories that must be considered when purchasing automated loading/unloading technologies. The model includes the purchase and operational loading costs that new technologies generate and the cost of adjacent operations to loading activity. The case study uses forklifts as the reference scenario and provides an overview of the return on investment and a break-even period when other technologies are in use. The calculation model shows that increasing cargo volume leads to a better RoI. The same observation is also made regarding the rise in labour costs. For the latter, using human operators to handle pallets on a one-by-one basis generates an exponential increase in operational cost due to delays and faults. On the other side, the cost of implementing automated loading/unloading technologies and the consideration of technology risk determine the low economic advantages. An in-depth cost and benefit analysis shows in which situation a technology generates greater benefits. Further results of this paper show that better use of trucks' loading capacity can positively impact the financial performance of automated loading technologies, as a higher volume of cargo is moved (at once) without human intervention.

Investigation of a stress-strain state of a rubber-cable rope with cables of different tensile rigidity

Purpose. Establishment of dependences for stress-strain state parameters in a rubber-cable rope with cables of different tensile rigidity and cable breakage. Research methodology. Construction and development of an algorithm for solving a model of a stress-strain state of a rubber-cable rope with ropes of different tensile rigidity and breakage of one cable by using the methods of mechanics of layered composite materials with soft and hard layers. Findings. Analytical expressions are constructed, which allow determining the main stress-strain state indicators in a rope with an odd number of cables, while the middle cable is damaged, and tensile rigidity of the middle cable is half the tensile rigidity of the other cables. Analytical dependencies are established for determining the extreme angles of rubber shear between the cables, what allows determining the most dangerous tension states of a rope with a damaged cable, which has a different rigidity from the other cables. The level of reliability of the developed algorithm for solving the model of a stress-strain state of a rubber-cable rope with cables of different rigidity is confirmed by determining the maximum tensile forces of a rope made of three cables, in which the middle cable has a tensile rigidity half that of the other two. The force distribution coefficients between cables adjacent to the damaged one are equal to 1.25 per unit load on each cable, which corresponds to the only possible case of force distribution between parallel elements under the presented conditions. Scientific novelty. The character of influence of different rigidity and damage of the reinforcing cables on the main parameters of stress-strain state in a rubber-cable rope are established. Practical significance. An algorithm for determining the stress-strain state indicators of a rubber-cable rope, which has an odd number of reinforcing cables, its middle cable is damaged, and the tensile rigidity of the middle cable is different (lower) than the rigidity of the other cables, is developed. This makes it possible to increase the operational safety of rubber-cable ropes in hoisting and transporting machines, in particular when operating at significant lifting heights, and also contributes to justifying the use of a rope design as a stay rope in capital structures.