Design and Performance Estimation of Mixed-Robotic Fulfillment System

E-commerce retailers face the challenge to assemble a large number of time-critical picking orders. Common parts-to-picker autonomous intelligent warehouses such as automated vehicle storage and retrieval system and robotic mobile fulfillment system are often a little ill-suited for these prerequisites. A mixed-robotic fulfillment system is a hybrid robot picking system based on multi-device collaboration. It is a fusion innovation of traditional automated vehicle storage and retrieval system and robotic mobile fulfillment system. This paper comprehensively considers the characteristics of the system and customer demand, through the construction of a queuing network model to evaluate the performance of the system. A series of problems such as order service time, throughput capacity, and vehicle quantity configuration are analyzed experimentally. The validity of the model is verified by a simulation model.

Modern Approaches in the Discovery and Development of Plant-Based Natural Products and Their Analogues as Potential Therapeutic Agents

Natural products represents an important source of new lead compounds in drug discovery research. Several drugs currently used as therapeutic agents have been developed from natural sources; plant sources are specifically important. In the past few decades, pharmaceutical companies demonstrated insignificant attention towards natural product drug discovery, mainly due to its intrinsic complexity. Recently, technological advancements greatly helped to address the challenges and resulted in the revived scientific interest in drug discovery from natural sources. This review provides a comprehensive overview of various approaches used in the selection, authentication, extraction/isolation, biological screening, and analogue development through the application of modern drug-development principles of plant-based natural products. Main focus is given to the bioactivity-guided fractionation approach along with associated challenges and major advancements. A brief outline of historical development in natural product drug discovery and a snapshot of the prominent natural drugs developed in the last few decades are also presented. The researcher’s opinions indicated that an integrated interdisciplinary approach utilizing technological advances is necessary for the successful development of natural products. These involve the application of efficient selection method, well-designed extraction/isolation procedure, advanced structure elucidation techniques, and bioassays with a high-throughput capacity to establish druggability and patentability of phyto-compounds. A number of modern approaches including molecular modeling, virtual screening, natural product library, and database mining are being used for improving natural product drug discovery research. Renewed scientific interest and recent research trends in natural product drug discovery clearly indicated that natural products will play important role in the future development of new therapeutic drugs and it is also anticipated that efficient application of new approaches will further improve the drug discovery campaign.

SIMULATION OF DESIGN VARIABLES EFFECT ON PERFORMANCE OF A COMMON BEANS (Phaseolus vulgaris L) PORTABLE THRESHER

In Kenya, threshing of common beans is mainly by traditional method using sticks and animal tramping, which are slow, inefficient and tedious. Consequently, there is a need to develop portable threshers locally available in the market for small and medium-scale farmers. The objective of this study was to simulate design variables effect on the performance of a common beans portable thresher. Sizing of design variables and parameters was key in development of bean thresher. This could be achieved by costly experiments or use of prediction mathematical model equation. The later method was used by developing mathematical models from combination of Buckingham pi theorem and reference to other similar work in literature. The predicting equation for power requirement, grain losses, grain damages, efficiency and throughput capacity were developed and validated using experimental thresher from the same study. The results showed that there was a positive correlation with R2 of 0.9. Based on actual data and 10% absolute residual error interval, the prediction performance of the developed models were above 77%. The results noted that increase in cylinder peripheral speed of the pegs resulted into increase in power requirement, bean grains damages, threshing efficiency and throughput capacity. Also increase in effective cylinder diameter caused increase in threshing efficiency and grain damages.

ANALYSIS OF TECHNICAL AND TECHNOLOGICAL PARAMETERS OF UKRAINIAN PRE-PORT RAILWAY STATIONS

Purpose. The aim of the work is a comprehensive analysis of the technical and technological parameters of pre-port railway stations in Ukraine as key elements of the port infrastructure, ensuring the interaction of railway transport with seaports. Methodology. In the process of research, the methods of analysis and synthesis were used to study the content and the main provisions of scientific publications on the issues of establishing effective interaction between rail and sea transport, with their subsequent comparison and generalization; methods of statistical analysis for research and systematization of technical equipment of port stations. Results. More than 60% of export cargoes go through Ukrainian ports; while 75% of export volumes are delivered to ports by rail. Currently, due to changes in the conditions for the functioning of the economy and the transport system of Ukraine, there is an imbalance between the capacities of ports and the port railway infrastructure for processing freight flows. Based on the analysis, it was found that the throughput of most stations does not correspond to the prospective, and for some stations - and the actual, volumes of work. In particular, for some stations, the capacity of track development is insufficient; a significant problem is also the low efficiency of the shunting means. An effective way to solve the problem of reducing the imbalance in the processing capacity of ports and the pre-port railway infrastructure is public-private partnership in the implementation of appropriate investment projects, the assessment of which should be carried out using modern scientific approaches. Scientific novelty. The authors have systematized the existing technical equipment of the port stations of Ukraine from the point of view of its sufficiency to ensure the existing and prospective volumes of transportation. Practical significance. The results obtained make it possible to provide a scientific basis for further research into assessing the throughput capacity of pre-port railway stations and the effectiveness of infrastructure projects aimed at increasing it.

Development and performance evaluation of a livestock feed chopper/pulverizer

Crop residues are bulky and low in nutrients. Their size reduction is imperative in order to compound them with other feed ingredients to achieve balanced feedstock for livestock. A chopping and pulverizing machine was designed and constructed to chop and pulverized feed materials. It comprises of chopping hopper, pulverizing hopper, metering device, chopping/ pulverizing chamber, screen and the processed feed outlet. The performance of the machine was evaluated on the basis of throughput capacity, pulverizing efficiency, scatter losses as dependent variables while moisture content was the independent variable. There were two level of speeds (1500 rpm and 2100 rpm) and five levels of moisture content (13 %, 16 %, 19 %, 21 %, 24 %, and 27 % dry basis). The throughput capacity, pulverizing efficiency had highest values of 222 kg/h and of 92.5 % respectively at moisture content level of 13 % (db) and 2100 rpm speed. However, the least scatter losses obtained was 2.5 % at moisture content level of 27 % (db) and 1500 rpm speed. As the moisture content increased, throughput capacity, pulverizing efficiency and scatter losses decreases at both speeds. The developed machine could enhance the use of crop residues in feeding livestock which could ultimately reduce the cost of livestock feed production.

Aspects of design and calculation of a railway track intended for dedicated passenger lines

The article considers issues of application of dedicated passenger lines for intertown and interregional transportation on the railways of the Russian Federation, which in the future will accelerate passenger traffic due to changes in transportation technology, increase the carrying and throughput capacity of railways, reduce construction costs and current maintenance, and optimize the need for infrastructure development. The structures of the track superstructure used for the transportation process at the present time were developed and implemented taking into account the mixed traffic — passenger and freight. Growth of axle loads in freight traffic, as well as the length of trains, presupposes the strengthening (weighting) of the standard structures of the railway track to possibly ensure the guaranteed safe passage of more than 1 billion gross tonnage. At the same time, exclusively for passenger traffic, the typical design of the railway track is redundant and can be optimized in terms of reducing the materials of the track superstructure with a simultaneous change in the configuration of repair schemes and current maintenance conditions. The article presents an assessing the possibility of using a “passenger” track structure on dedicated passenger lines for intertown and interregional transportation according to the criteria of the allowable margin of safety in the environment of fnite element analysis — the most progressive method for calculating structures undergoing complex loading. The article presents the results of calculations of the stress-strain state of a railway track of various confgurations, including promising lightweight versions with R50 rails and reinforced concrete sleepers with under sleeper pads. Based on the calculations performed, recommendations are given for the areas of application of the considered track confgurations from the point of view of permissible stresses in its elements.

Routing Optimization Based on OSPF in Multi-Layer Satellite Network

Multi-layer satellite network has become a hot spot for its wider coverage and higher bandwidth level. However, due to the frequent link changes and complexity of network, it is hard to find out a mechanism to handle well on long delay and high packet loss level. This paper proposes an optimized OSPF protocol called OOWLP to eliminate unnecessary routing convergence to optimize the packet loss level and delay ultimately. Link plan table, which records link contacting plan, will be used to update the link state database periodically so that we can eliminate the flooding procedure caused by scheduled link changes. On the other hand, Constrained Shortest Path First (CSPF) will be used to get business differentiated routes in multi-layer satellite network to optimized the throughput capacity in congestion scenario. We divide the sending packets into different businesses and get the routes for each business with longer duration limited by remaining bandwidth. Simulation results show that in normal scenario, average packet loss rate and delay performance are improved 17.42%, 51.44ms respectively, average packet loss rate and throughput capacity performance are optimized 79.05%, 9.81Mbps respectively in congestion scenario compared to standard OSPF. As a result, the proposed mechanism is able to shorten the average delay and lower the packet loss level in multi-layer satellite network.

Development of HTU-model variable chipping clearance cassava chipper

The objective of this research was to design, construct and evaluate a variable chipping clearance cassava chipper for processors which will produce uniform and varying cassava chip geometry for multipurpose usage. It consists of a drive shaft with varying chipping clearances (6, 18, and 28 mm) to produce varied chip geometry. The average throughput capacity of the chipper was found to be 475.5 kg·h^–1 at a speed range of 460–800 rpm with a chipping clearance of 6–28 mm. The average chipping efficiency ranges from a minimum–maximum of 76.6–99.4% for the selected operational speeds and chipping clearances. The chipping capacity and the output to input ratio is dependent on the operational speeds and chipping clearances of the machine.

DETERMINATION OF DESIGN PARAMETERS OF A STEP DISK MILL

The calculation of the design parameters of a disc mill equipped with a feeder made in the form of a conical hopper is given. For shredders of the disintegrator type, it is very important to ensure the uniformity of loading of the crushed material of the working zone of active impact on particles. In addition, the most important factor is the throughput capacity of all sections of the grinding plant. The throughput should be determined by the design and technological parameters of the working chamber of the mill. Its overload can lead to a blockage of the working chamber, and insufficient throughput will negatively affect the intensity and effectiveness of the impact on the particles of the material. For example, insufficient concentration of particles in the secondary zone of the grinding chamber leads to a decrease in the efficiency of mutual abrasion. The article attempts to determine the design and technological parameters in the loading and accelerating parts of the disk mill. At the same time, it is necessary to coordinate the throughput of the disk spreader and the volumetric flow rate of the material particles flowing from the hopper. In this case, it is advisable to take into account that as a result of a rather high rotational speed and the size of the initial particles, with the wrong height of the radial blade of the spreader, material particles can roll over the radial blades, which leads to a delay of the material in the zone of the spreading disc. Therefore, it is necessary to determine the calculation formulas for finding the required height of the radial blade of the spreading disc, depending on the size of the initial particles. The formula demonstrates that the height of the separating blade depends on the particle size, the speed of rotation of the disks and the distance to the point of meeting of the particle with the radial blade.

DETERMINATION OF DESIGN PARAMETERS OF A STEP DISK MILL

The calculation of the design parameters of a disc mill equipped with a feeder made in the form of a conical hopper is given. For shredders of the disintegrator type, it is very important to ensure the uniformity of loading of the crushed material of the working zone of active impact on particles. In addition, the most important factor is the throughput capacity of all sections of the grinding plant. The throughput should be determined by the design and technological parameters of the working chamber of the mill. Its overload can lead to a blockage of the working chamber, and insufficient throughput will negatively affect the intensity and effectiveness of the impact on the particles of the material. For example, insufficient concentration of particles in the secondary zone of the grinding chamber leads to a decrease in the efficiency of mutual abrasion. The article attempts to determine the design and technological parameters in the loading and accelerating parts of the disk mill. At the same time, it is necessary to coordinate the throughput of the disk spreader and the volumetric flow rate of the material particles flowing from the hopper. In this case, it is advisable to take into account that as a result of a rather high rotational speed and the size of the initial particles, with the wrong height of the radial blade of the spreader, material particles can roll over the radial blades, which leads to a delay of the material in the zone of the spreading disc. Therefore, it is necessary to determine the calculation formulas for finding the required height of the radial blade of the spreading disc, depending on the size of the initial particles. The formula demonstrates that the height of the separating blade depends on the particle size, the speed of rotation of the disks and the distance to the point of meeting of the particle with the radial blade.