Number Of Transport Units Research Articles

Justification of the Use of Container Technology in Dumping

The increase in the depth of the quarry is associated with an increase in the work of quarry transport in limited areas, requires a constant increase in the number of transport units, which increases the environmental burden on the environment. The rock mass extracted from the quarry is stored in external dumps, which occupy large areas and significantly worsen the ecology of the region. The operation of mining equipment on dumps with existing technologies causes a number of problems, the main of which is the movement of equipment near the prism of a possible rock collapse. It is proposed to use container technology for transporting the laying rocks in the dump, where the main element of the technology is a mobile lifting machine, which eliminates the need to build roads or railways on board and on the surface of the dump. Self-unloading of container equipment allows you to pour the rock mass directly to the place of laying on the dump. Containers with rock are installed in front of the front of the dump, and the lifting machine is placed on a special platform of the dump. The rock mass is delivered from the faces by dump trucks of any load capacity and unloaded into the hopper of a plate feeder, which fills the containers as they are fed by a quarry lifting machine. the rock is laid in horizontal layers within the step of moving the lifting machine. The weighted average height of the rock rise is equal to half the height of the dump tier. With the new technology, the entire amount of work will be performed by one lifting machine. Increasing the height of the dump to 80 meters with a new method of dumping, reduce the area occupied by dumps by 175 thousand m2 per year. The use of container technology in the formation of the dump allows, when unloading rock from containers into the dump, to reduce energy consumption during the formation of the dump, and increase the economically advantageous height of the dump. This reduces the area occupied by dumps and reduces the harmful effects of mining on the environment. The article discusses the technology of dumping during the formation of dumps using bulldozers in the conditions of Northern Kazakhstan. Traditional technology involves the involvement of a complex of equipment consisting of 8 dump trucks and 1 bulldozer. According to the new technology, the same amount of work can be done thanks to 1 lifting machine. Based on the calculations carried out, it was found that the intensity of dust emissions from internal sources decreases by 1,576 tons per year. A decrease in dust emissions is also observed with an increase in the height of the dump due to a decrease in area, while the difference was 75.57 tons per year. The total decrease from container technology is 1,651.57 tons per year.

Simulation based optimization of drilling equipment logistics: a case of study

Logistics in the oil and gas industry (O&G industry) represent approximately from 5% to 15% of the total costs thus a failure in logistics has an important impact in the whole supply chain and considering the trillion of dollars invested in oil and gas projects development in the upstream stage of the chain value any increase of efficiency in the logistics activities represent an important advantage. We used the Agent Based Simulation (ABS) to simulate the initial proposed route a single transportation agent must take to move the drilling equipment among the oil wells and the time it took using this first route; then we simulated optimized routes and because the absent of data we made different iterations with different rigs number to optimize much more the time service of the transportation agent, so we optimized the time and the number of transport units that must be employed to reduce time and costs of delivery.

A multi-period sustainable hydrogen supply chain model considering pipeline routing and carbon emissions: The case study of Oman

This paper presents a mathematical model for a multi-period hydrogen supply chain design problem considering several design features not addressed in other studies. The model is formulated as a mixed-integer program allowing the production and storage facilities to be extended over time. Pipeline and tube trailer transport modes are considered for carrying hydrogen. The model also allows finding the optimal pipeline routes and the number of transport units. The objective is to obtain an efficient supply chain design within a given time frame in a way that the demand and carbon dioxide emissions constraints are satisfied and the total cost is minimized. A computer program is developed to ease the problem-solving process. The computer program extracts the geographical information from Google Maps and solves the problem using an optimization solver. Finally, the applicability of the proposed model is demonstrated in a case study from Oman.

Modeling of the two shuttle box system within the internal logistics system using simulation software

Abstract The efficiency and effectiveness of the production system are influenced by the logistical arrangement of material flows. The smooth production, especially for assembly lines in the required quantity and at the required time (JIT or JIS systems), is currently ensured by automatically controlled towing sets (logistics trains), which consist of a tractor and several trucks. Another factor that affects the smooth production of assembly lines is the system of controlling the circulation of transport units. The number of transport units used in combination with the transport system significantly affects the efficiency of assembly workplaces. This article presents an analysis of the supply of assembly workplaces using a system of two shuttle boxes. The aim of this article is to investigate the influence of transport speed and capacity on the smoothness of the assembly process. Within the described analysis, the transport of 50,000 components is analyzed using a simulation model, while the length of the transport route is 32 km and 65 transport units per shift are used.

TRAFFIC-RELATED MORTALITY IN MOLDOVA

This article analyses the mortality caused by road accidents in Moldova depending on the degree of involvement of pedestrians, cyclists, motorcyclists, drivers and passengers of transport units, depending on age and sex. Results suggest that traffic-related mortality in Moldova has shown an increased incidence among the young and working-age population, where a significant difference between males and females is observed. Among the youth, traffic-related deaths register between 10-27% of the overall mortality in both sexes. The risk exposure of dying in a traffic accident decreases with age and is less significant in the retired ages. During the years 1998-2015, avoidance of trafficrelated deaths would have assured an increase in life expectancy between 0.40-0.56 years in males, and 0.09-0.23 years in females. The continuous increase in the number of transport units on public roads, as well as in the number of hours spent in traffic, influences the degree of exposure to the risk of death or injury as a result of road traffic accidents. Trauma resulting from road accidents increases the incidence of premature mortality and disability among the population, which is reflected by the decrease of healthy life expectancy. It is ascertained that the road accident mortality requires a detailed and comprehensive analysis given the multitude of factors influencing deaths and injuries related to a traffic accident among the population. Thus, in order to improve road safety and reduce mortality incidence among traffic participants, a range of actions has to be implemented by the liable actors, including through the international experience.

Analysis of the Rail Transport Market in Poland

Purpose: The study's objective is to evaluate the changes observed in the rail transport market in Poland. The analysis covers both the market of freight services and the conditions of passenger transport. The materials used in the analysis consist of records of the Central Statistical Office (GUS) and record sheets and reports of the Railway Transport Office (UTK). The studied period covers the years 2010-2019. Design/Methodology/Approach: A two-step process undertook the research. The first step involved an analysis of changes in the market of freight services. The analysis was performed via an evaluation of freight's total mass, the volume of transport activity (performance), and the volume of train operations. The scope of changes on the market of intermodal freight transport was analyzed in detail. The second step was an examination of changes in the market of passenger transport. Here, the assessment involved the number of passengers carried and individual rail carriers' involvement in the execution of the transport process. Also, the drivers of rail utilization rate differentiation were investigated. Findings: Concerning rail freight transport, an area of particular intensity is intermodal transport. Over the period 2010-2019, there was an over the four-fold rise in the total mass of freight and the number of transport units. The analysis conducted in the field of passenger transport showed its growing importance. The rail utilization rate demonstrated that, statistically, every Polish resident traveled by train more than 8 times per year. The above results tended to increase year by year. Practical Implications: The conducted analysis indicates that thanks to intermodal freight transport, rail transport can be highly competitive when it comes to other modes of transport. It is becoming an interesting alternative also to road trips. Rail popularization is in the hands of public transport associations in individual regions. By developing regular timetables and frequency of transport services, the purchase and retrofitting of rolling stock can contribute to the industry's growth. Originality/Value: The study presents the core factors affecting rail freight and passenger transport development. The analysis of rail utilization in individual regions could provide a basis for strategic decision-making regarding rail transport policy development directions. This may pertain not only to state-wide but also to local activities.

Optimization of Passenger Traffic in a Major Transportation Hub

The article presents a model for optimizing the activities of railway transport when organizing passenger transportation in a major transportation hub. When optimizing the calculations determine the number of vehicles that are assigned to the node; optimal rates for transportation; the number of transport units in the directions depending on the random demand for transportation. The possibility of attracting additional transport units in case of insufficiency of their own is taken into account. The model takes into account the influence of competitive transport (road). The solution of this problem in general requires the use of statistical modeling and nonlinear programming. Keywords optimization model, statistical modeling, optimal freight rates, non-linear programming.

The effect of absorption process parameters on its efficiency

In this work we are presenting the results of studies of the effect of hydro and aerodynamic parameters of the process of water vapor absorption during intensive bubbling in the dynamic foam mode on the absorption process efficiency. As a result, it was found that the hydrodynamic characteristics (height of the foam layer of the absorbent and its resistance) and aerodynamic characteristics (gas velocity, longitudinal mixing in the gas phase) have the main influence on the efficiency of the absorption process. We also investigated the effect on the efficiency of the process of kinetic characteristics, characterized by the number of transport units and absorption factor. We have proposed to estimate the overall efficiency of the process, taking into account the degree of extraction, as well as the energy characteristics (hydraulic resistance), weight and size characteristics and the drop entrainment volume. For this purpose, for the overall assessment we have proposed to introduce a conditional optimality ratio, allowing to make a comparison of both various contact devices and absorbents.

Minimising manpower in rice harvesting and transportation operations

Manpower is an important input parameter for both strategic and tactical management levels in agricultural production systems, connected to management tasks such as capacity planning, task times planning, and scheduling. In large scale field operations manpower surplus can lead to an unnecessary increase in operational cost, while, on the other hand, manpower shortages in the absence of appropriate planning can lead to reduced productivity with a high risk for timeliness costs. In this paper, the simulation model reported by Busato [Busato, 2015, A simulation model for a rice-harvesting chain. Biosystems Engineering, 129, 149–159] was extended to incorporate the functionality of the minimisation of manpower in large scale field operations, such as crop harvesting and transportation. Specifically, the model implements the practice where the number of transport units' operators is lower than the number of transport units. The simulation model was validated based on measurements in two harvesting and transport operations. The deviation of the predicted operation parameters as compared to the measured ones was relatively low. Specifically, for the case of area capacity the error in the prediction was 2.2% and 2%, respectively, compared to the measured area capacity in the two operations. Regarding the practice of the reduced number of operators, it was shown that there are significant reductions in required manpower use when fewer operators than the number of transport units are implemented in the operation. For the specific transport units-operators configurations examined, the reduction of manpower use (h ha−1) was in the range of 12%–30%.

Determination of the number of transport units from data on equilibria in binary mixtures

Relations for analytical determination of the number of transport units are suggested. These relations contain coefficients found from experimental data on equilibria in binary mixtures. Examples for four binary mixtures are considered.

Determining the Permeable Efficiency of Elements in Transport Networks

The transport network is simulated by a directed graph. Its edges are evaluated by length (in linear units or time units), by permeability and by the cost of driving through in a transport unit. Its peaks (nodes) are evaluated in terms of permeability, the time of driving through the node in time units and the cost of driving a transport unit (set) through this node.For such a conception of the transport network a role of optimisation and disintegration of transport flow was formulated, defined by a number of transport units (transport sets). These units enter the network at the initial node and exit the network (or vanish at the defined node). The aim of optimization was to disintegrate the transport flow so that the permeability was not exceeded in any element of the network (edge, nod), so that the relocation of the defined transport flow was completed in a prearranged time and so that the cost of driving through the transport net between the entry and exit knots was minimal.

Conventional heat exchanger design methods and their applicability to thermoacoustics

Heat exchangers (HEX) play an important role in many engineering applications, and well established methods for their modeling and optimization are available. Conventional heat exchangers take advantage of forced convection or phase change to transport thermal energy from the hot to the cold fluid, as opposed to thermoacoustic applications where the mean velocity of the oscillatory flow is zero. Conventional HEX are typically classified according to flow arrangement and type of construction. The most commonly implemented methods for HEX analysis are the logarithmic mean temperature difference (LMTD) method and the number of transport units (NTU) approach. Both methods require a set of input parameters and the analysis yields, for example, the appropriate heat exchanger size, i.e., the heat transfer surface area, and type that achieve the desired fluid outlet temperature. The applicability of conventional heat exchanger design methods to thermoacoustic HEX is explored. HEX design solutions developed for thermoacoustics are analyzed in light of the LMTD and NTU approaches. Key differences and issues requiring further research are addressed in the study. [Work supported by the Office of Naval Research.]

Sodium-Magnesium Exchange in Erythrocyte Membranes from Patients with Affective Disorders

The Vmax of erythrocyte sodium-magnesium exchange was measured for the first time in 63 patients suffering from affective disorders and compared to that in 33 healthy subjects. Depressed patients had a significantly higher Vmax (215 +/- 13 vs. 151 +/- 14 mumol/l.cells/h; p < 0.005; mean +/- SEM). This tendency was conserved after division of the 63 patients into three clinical subgroups according to the DSM-III-R criteria. Thirty-four patients from this panel were divided into three subgroups according to the chemical class of the antidepressant drug used and were followed up during a 3-month period of drug treatment. Mood improvement over the 3-month period was associated with a slow increase in Vmax of Na/Mg exchange (delta increase approximately 25 mumol/l.cells/h), except in the subgroup of patients treated with non-tricyclic antidepressants (n = 8). These results are consistent with the previously reported link between high erythrocyte magnesium content and affective disorders. Indeed, enhanced Na/Mg exchange Vmax, which probably results from an increased number of transport units per cell, contributes to the normalization of red blood cell magnesium content correlated with mood improvement.

Monte-Carlo-simulations of voltage fluctuations in biological membranes in the case of small numbers of transport units

Some years ago a theory of non-equilibrium voltage fluctuations in biological membranes was developed (Frehland and Solleder 1985, 1986) under a linearisation condition which is valid for a great number of transport units. In order to get an insight into the stochastic behaviour of such systems, consisting of small numbers of transport units, we carried out Monte-Carlo-simulations and compared the mean voltage course and the spectral density with the results of the previous theory. Under parameter conditions of biological relevance no significant differences from the behaviour of systems with large numbers, as predicted from the earlier theory, could be found in the case of rigid pores and ion carriers. However, in the case of small numbers, channels with open-closed-kinetics showed great deviation. With increasing number of transport units agreement with the previous theory was obtained.

Determination of the region of asymptotic stability for a CSTR

The dynamic behaviour of a continuous stirred tank reactor (CSTR) has been the subject of many published works, expecially with regard to the possible occurrence of particular phenomena like permanent oscillations, the so called “limit cycles”. The Hopf Bifurcation Theory has been well exploited and today it is actually possible to predict the dynamic behaviour of the reactor in the entire parameters space. Starting from this basis, our aim is: “After ascertaining that the reactor operation is stable for a particular choice of parameters set, which are the maximum perturbations we can accept to be sure not to change the operating point?” We determine the region of asymptotic stability (RAS) by means of a particular reversing-time integration technique for a refrigerated CSTR where an irreversible first-order exothermic reaction takes place. After taking into account the influence of the parameters which characterize the reactor, such as the number of transport units, the behaviour of the system connected to a control loop is studied, in order to point out how the control system can affect the size of RAS.