bluuebunny/crossref_metadata_2025 huggingface dataset:
An Exposition of Speculative and Numerical Analysis of CFST Columns
Authors: Gireesh Kumar Pala , Sai Charan Seethalam , Sri Mani S Reshma , Nagarjuna Kundeti
Published: December 2020

Owing to the advantages like intense compressive strength, large ductility and enormous energy incorporation, Concrete filled steel tube column system is gaining momentum when set side by side to regular steel or reinforced concrete system. Local buckling is one such major advantage that CFST gives experimental results from various articles has proven that there is an increase in the properties of CFST over normal concrete systems. This paper aims to give brief understanding on the experiments works conducted and numerical results obtained from various articles are discussed. Experimental works exposed to view that circular concrete filled steel tubes were more appropriate than square concrete filled steel tubes. In this paper, nonlinear finite element analysis for concrete filled steel tube is effectuated through varied parameters like concrete infill grade, as short columns with diameter ratio (L/D) not exceeding 4.5 with devoid of slenderness have also been discussed. The past studies divulged that the increment of D/T ratio dwindles the load carrying capacity of CFST and moreover, the high concrete infill grade buttress the load carrying capacity. From various literature reviews it was also concluded that the confinement efficacy of concrete enlarges the resistance to axial loading of compound columns with concrete filled circular sections. Furthermorefor the CFST columns the buckling failure can be evaded, as well as the load carrying capacity can be strengthened by hauling down the slenderness ratio. Therefore ample scope exists in carrying of numerical analysis using ANSYS to find the potential of CFST columns.
The effectiveness to cleanup oil spills from the water environment of the combined sorbent on the basic of PUF and chitin
Authors: Trang T Y D , Zenitova L A
Published: December 2020

This study provides information about evaluating the parameters (density, buoyancy, sorption capacity) of a combined oil sorbent based on polyurethane foam filled with chitin (PPU10M). In comparison with the original chitin, the developed sorbent has better buoyancy, and commensurate with the pure polyurethane foam (PUF). The effect of the contact time, the type of the water, the thickness of the oil layer and the adsorbent dosage are studied. The results show that the optimal contact time of the sorption process is 60 minutes. In which, the oil capacity of the sorbent PPU10M in artificial seawater reaches 13.6 g/g and in artificial river water 13.2 g/g. The sorbent dose depends on the thickness of the oil layer on the water surface. For a thin oil layer, the use of 1g of adsorbent reaches higher oil capacity but the oil removal percentage lower in comparison to the dose of 2g sorbent. For an oil layer thickness equal to or greater than the height of the sorbent cube, the efficiency of oil removal is observed better when using 2g of sorbents. Thus, it is considered that the use of 2g sorbents is optimal. A generalization of the research results indicates the prospects of the developed combined sorbent based on chitin and polyurethane for oil spill treatment.
Estimation of anti-chlorosis action of iron-lignosulfonate complex synthesized by anodic dissolution of iron
Authors: Khabarov Yu G , Veshnyakov V A , Shergin A E
Published: December 2020

Iron-lignosulfonate complexes are used as trace element fertilizers to control plant chlorosis caused by iron deficiency. In this study, iron-lignosulfonate complexes were synthesized by anodic dissolution of iron in solutions of sodium lignosulfonates or lignosulfonic acids. The resulting solutions of the iron-lignosulfonate complex do not contain extraneous ions that are present in similar preparations synthesized chemically from salts. Electrosynthesis of iron-lignosulfonate complexes was carried out with two iron electrodes with alternating polarity, changing the period of switching the polarity of the electrode, temperature and the duration of electrolysis. The anti-chlorosis action of the synthesized iron-lignosulfonate complex was tested while growing lupine on calcareous soil. The plants were treated with solutions of the synthesized complex by the non-root method after 10 and 20 days of their cultivation. For comparison, lupine was also grown on normal soil and on calcareous soil without iron-lignosulfonate complex treatment. The content of chlorophyll, the content of carotenoids and the mass of the ground part of the plants treated with the synthesized complex were the same or higher than those of the plants grown on normal soil. In addition, all these parameters were 2-3 times higher than that of the plants grown on calcareous soil without treatment.
Environmental mapping of radiation-hazardous areas
Authors: Abisheva M T , Monayenko V N , Khlebnikova E P
Published: December 2020

The article presents algorithmization of notation design process using computer technologies for environmental maps design. Cartographic models displaying natural resources are considered as an example. The results of model color design based on developed coloristic principles for the adjacent territory in the area of the “Sary-Uzen” test site of the former Semipalatinsk Nuclear Test Site are presented. As a solution of environmental mapping tasks, the authors have shown the possibilities of territories assessment and using the results to create and update thematic layers in the GIS.
Livestock enterprises waste utilization for heat system supply to rural buildings in Yakutia
Authors: Druzyanova V P , Kokieva G E , Savvateeva I A , Khiterkheeva N S , Kilchukova O K
Published: December 2020

In recent years, interest in issues of using natural energy sources significantly increased due to limited resources of fossil fuels and state missions of environment protection from pollution. One of the main areas of the researches is heating and hot water supply system development for country house using heat pump systems (HPS) based on non-traditional power sources in moderate climate conditions.
Production of Biogas using method of agricultural waste fermentation
Authors: Kokieva G E , Protodiakonova G P , Dondokov U Z , Shalbuev D V , Voinash SA
Published: December 2020

During using biogas as fuel for diesel engines, it is necessary to clean it from hydrogen sulfide, water and carbon dioxide, as well as to compressing it to fill cylinders more efficiently. Today the production of biogas in agriculture is the disposal of crop waste and manure from livestock farms.This approach is very actual, at the first stage of its implementation was planned to create the necessary material and technical base to widespread using of non-traditional energy sources, including organic biomass energy (fertilizer, crop waste, etc.). In addition, environmental protection, which also requires intensive and rational processing of animal waste, is very closely connected with the problem of waste disposal. This necessitates the search for processing methods that would ensure the comprehensive utilization of its agricultural, energy, feed and other properties. This article presents the technology for processing the utilization of manure using microbial synthesis. When processing manure in anaerobic conditions, the threshold lowered for its smell, germination of weed seeds, helminths die, and nutrients (nitrogen, phosphorus, and potassium) are completely preserved. The resulting biological gas contains up to 70 % methane, and its calorific value is 24 MJ/M3. The introduction of low-waste, resource-saving technologies with mechanization and automation of production processes plays an important role in the environment protection issues from livestock complexes waste in their further development. At present, there are several directions of processing of agricultural and water waste. At the same time, processing of animal waste with the use of biogas plants gives a significant socio-economic effect, expressed in improving working conditions, increasing the production culture and land use. Moreover, the environment protection rask is being solved.
Investment attractiveness of the territory, greening and self-recreation of citizens: Northern regions
Authors: Vladykina Yu O , Donets N J , Rozumnaya N V
Published: December 2020

Abctract. Interest in involving countryside territories in economic turnover occurs the various ways. Housing construction, development of agro-industrial complexes, introduction of innovative technologies, redistribution of the land Fund, etc. The main problems: lack of coordination of actions, unidirectionality of agroeconomic, working in areas of risky farming, seasonal employment. At the same time, socio-economic and infrastructure issues remain out of attention: priority and procedure for financing social facilities, strategic planning of village territories, industry interaction and total environmental impact on the territory. The lack of interaction between stakeholders allows us to solve only operational tasks. Increasing the investment attractiveness of the territory requires a comprehensive approach that provides a synergistic effect of industries. Systematic redistribution and involvement of free population flows in rural labor allows not only to satisfy the growing interest of citizens in active forms of recreation, but also to ensure the introduction of organic forms of agriculture in agricultural activities. The study of recreational motivation in combination with branding of rural areas allows us to predict not only investment activity, but also the reorientation of citizens towards environmentalization and self-employment [1].
The effectiveness of vermigumates under the conditions of vegetation experience
Authors: Kallas E V , Rodikva A V , Kulizhskiy S P
Published: December 2020

The effectiveness of biofertilizer, which was obtained by extracting humic acids from vermicompost 0.02 n NaOH, is shown. The increase in the productivity of the test culture in the growing experiment against the background of watering with the vermigumate (dilution 1:50) was 73% in relation to the control.
Study of Biological Characteristics of Leucinodes orbonalis Guenée which Destroyed Young Shoot and Fruit of Eggplant (Solanum melongena L.): A case in Trang Bom district, Dong Nai province, Vietnam
Authors: Hung Vu Van , Viet Hung Dang , Thi Lan Anh Dang
Published: December 2020

Leucinodes orbonalis Guenée adult had white insect into dark brown colour. Wings were marked by three small triangular with a pinkish to bluish colour mixed pinkish orangish or dark brown. L. orbonalis female dimension were about 9.6 – 12.3mm, the dimension of L.orbonalis male were 8.1 – 9.5mm. Eggs were 1.0 – 1.2mm in length and oval or elliptical shape. The incubation time was around 5.0 – 6.0 days. Larvae are developed by six stages of age, larvae development period lasts 10 – 12 days. Pupae were pink to dark pink in colour and shiny with the length, width were 11.47 – 15.33 mm, 4.40 – 6.45mm respectively. Pupae developed about 8 – 9 days. The life cycle of L. orbonalis lasted 25.30 ± 0.92 days. L. orbonalis feeding in laboratory had high hatching rate, just 9.36% were not hatched. The early stage of larvae had high death-rate (27.98%) mainly due to dispersion. The older larvae had lower death-rate (10.12%). Pupae had high developed rate, only 4.10% were not development. There were equal rate between male and female adult of L. orbonalis. Laying eggs period of female adult lasted 3 days, in there the first day was the highest laying rate (113 eggs/female/day). L. orbonalis densities were highest on the young shoot and fruit of eggplant at the stage after planting 95 – 150 days and was reduced in a after growing.
The Technology of Dehydrated Soup Base from Poultry Meat and Bone Residue
Authors: Polyanskikh S V , Danyliv M M , Dubrovina U R , Ozherelyeva O N , Vasilenko O A
Published: December 2020

This research paper describes the technology for obtaining dehydrated soup base from the meat and bone residue obtained during the primary processing of poultry. The authors proposed a rational cutting of poultry and assessed the chemical composition of the meat and bone residue; during experimental studies it was found that a significant amount of fat predominates in the bone residue, where skin from the neck was used and makes up 21.3%, the protein remained at the level of 22.7 % Water-soluble proteins predominate in the meat and bone residue and make up 52.3 and 63.1% for the residue from the carcass and the residue from the carcass and skin, respectively, the mass fraction of alkali-soluble proteins is 23.5 and 17.6%, respectively. The total mass fraction of essential amino acids is lower than in minced meat, the limiting amino acids are lysine (71%), leucine (69%), and threonine (68%). To organize the convection drying, we used a dryer with a liquid vibro-boiling bed.
Influence of inclination angle of piezoelectric receiver of ultrasonic sensor on the error in measurement of the average fiber diameter
Authors: Bagaev A A , Kulikova L V , Kunitsyn R A
Published: December 2020

During experimental studies, an ultrasonic device was used which in terms of design ensured maximum acoustic pressure on the receiving element, minimized the effect of external disturbances (environmental condition parameters) on the measurement result; decreased spatial variations of the source and receiver of ultrasonic waves during measurement, optimized the design and spatial positioning of ultrasonic vibration receiver.

The measuring channel settings accepted during experimental studies are as following: ak -design constant of measuring channel; ak = 14, where a is half-width of the channel, a = 5 mm; k - wave number, k = 2.8. Experimental evaluation had confirmed theoretically substantiated effect of inclination angle of the receiving element of the ultrasonic sensor on the error in measurement of wool fineness in a disarrayed sample. At the inclination angle of the ultrasonic sensor receiver of fi = 48° relative to the longitudinal axis of the measuring channel, the error does not exceed ±1.5%, and at the angle offi = 0° it does not exceed ±5%.

The reason for more accurate measurement of wool fineness at fi = 48° in accordance with the developed theoretical provisions is that the inclination of the receiving piezoelectric element of the sensor relative to the longitudinal axis of the measuring channel eliminates the need for receiver installation at the angle of fi = 0° strictly in so-called ultrasonic wave antinode, which poses a significant technical problem at ultrasonic wave frequency of 150 kHz. Besides, the receiver arrangement at inclination relative to the longitudinal axis of the measuring channel allows increasing the spots of contact of ultrasonic wave with the surface of the receiving element irrespective of wave phase, and increases the average acoustic pressure and decreases the measurement error.
Assessing the forcing level of air cooled diesel engine considering parameter spread of boosting system
Authors: Lartsev A M , Salykin E A , Fedyanov E A
Published: December 2020

Spread of parameter values of piston internal combustion engine boosting parts is normally due to extreme deviations (spread, error margin) of original parts and quality of assembly. Spread of relation of boosting pressure to counter pressure at outlet of turbo compressors Pk/Pt of the same type affects not only the engine parameters, but also thermal expansion of cylinder-piston group parts and cylinder head. At stable relation value of Pk/Pt, boosting pressure and maximal air flow, turbo compressor allows us to reduce the thermal factor of combustion chamber and cylinder head due to higher values of air excess ratios. This is very important, first of all for air cooled engine as in case of dramatic surge of its thermal factor we face a risk of cracks occurring in inter valve and inter valve- nozzle connectors of cylinder head fire bottom, cracking of setting bevels at valves of gas distribution mechanism. We analyzed the impact of technological spread of boosting details parameter on the value of achieved forcing limit. Impact analysis of technological spread of turbo compressor parameters on diesel engine performance was done on the basis of test results of ten B-400 engines, fitted with randomly selected pairs of TKP8,5-C7 turbo compressors out of a lot of 20 pieces. For each turbo compressor we determined preliminarily characteristics and efficiency factors nK, of turbine nT and of a unit as a whole n™.
Application of the photoelasticity method for studying the stress-strain state of the tribomechanical system “ring-bearing housing”
Authors: Vakhrushev V V , Nemtsev A E , Ivanov N M , Shindelov AV
Published: December 2020

In this paper, we consider the use of the polarization-optical method for assessing the stress-strain state of films of polymeric material in the restored tribomechanical system “bearing ring - housing” and the dependences for determining the magnitude of the principal stresses are proposed.

When studying the stress-strain state, compounds with a diameter of the contact surface of 40 mm from an optically sensitive material imitating an adhesive layer were used as models. The photoelasticity method showed that the maximum stresses occurred on the axis of symmetry of the model, and the contact arc was 180 degrees. A qualitative picture of the strips indicates the identity of the stress-strain state of the adhesive joint model both for the uniform gap model and for the eccentricity models.
A finite differences approach for fluid-structure interaction in a hydrostatic compliant thrust bearing
Authors: Marinescu A A , Cicone T
Published: December 2020

It is well known since the pioneering work of Dowson and Castelli that load capacity increases in compliant (elastic pad) hydrostatic bearings, compared to their rigid counterparts. In a recently published paper, a new design solution of a flexible pad hydrostatic bearing was proposed and analysed theoretically. A simplified analytical model was proposed for the fluid-structure interaction. The model was based on two important simplifications: linear pressure distribution on the bearing land, used to calculate the deformation of the pad, and parabolic variation of film thickness in the Reynolds equation. The analysis was made for isothermal conditions and constant pressure in the recess. This new approach relaxes the two simplifications by considering a linearly elastic model for the flexible pad and including its deformation in the Reynolds equation. A finite differences scheme is proposed for both the fluid flow and elastic deformation, considering the flexible plate simply supported. The consistency and convergence of the iterative solution are analysed, and comparisons with previous analytical solutions are shown. These results show the limits of the accuracy of the simplified analytical model and allow the selection of the design parameters of a test rig.
New concepts in friction reduction in preloaded assemblies of angular-contact ball bearings
Authors: Zamă A , Olaru D , Paleu V
Published: December 2020

Angular contact ball bearings are able to simultaneously accommodate both radial and axial loads. The application filed of ball bearings ranges from the automotive industry, machine tools, machines and equipment for electricity generation to household appliances. This paper presents the current state of the research undertaken in the field of ball bearings friction reduction and summarizes the conditions needed to achieve this by making use of preloading. In order to test the influence of preloading on ball bearings friction, the authors of this paper are also presenting a new device that was designed for the testing of angular contact ball bearings.
Morphological and tribological studies of thermal plasma jet deposited coatings used in cardan joints
Authors: Dascălu A , Istrate B , Munteanu C , Paleu Cîrlan C , Paleu V
Published: December 2020

All wheels drive (AWD) and railway vehicles require a longitudinal transmission. Double cardan joint is one of the most employed transmission, as it allows misalignments between the shafts. This transmission must support the maximum motor torque and high dynamic loads. In such situation, from tribological viewpoint, cardan joints are subjected to abrasive wear. To increase wear resistance of cardan joints, its rolling elements can be coated with ceramic or metal-ceramic coatings. This paper presents an experimental research on microstructure and dry friction characteristics of two steel samples obtained from cardan crosses (40Cr10 and RUL2), coated by two types of metallic powders (METCO32 and METCO72). Microstructural studies of both surface and cross –section of samples were performed using scanning electron microscopy (SEM). Dry tribological tests at constant speed and load were carried out on AMSLER machine. The micro-structural experiments revealed a structure with a relatively homogeneous character, partially melted particles and several microcracks being detected. Following the tribological tests, it was found that the METCO72 coating provides the lowest coefficient of friction, near values being obtained for both substrates of 40Cr10 and RUL2. The best combination is formed by 40Cr10 substrate and METCO72 coating.
Contact stress simulation problem in case of the Mg alloys
Authors: Lupescu S , Munteanu C , Tufescu A , Istrate B , Basescu N
Published: December 2020

This paper highlights the simulations of the contact stresses generated in the case of the load applied on biodegradable alloys based on Mg (Mg-0.5 Ca-xY), starting from previous studies done on these alloys and the homogeneity of the materials in different areas. Thus, it was tried to establish the parameters necessary for modeling, so that it would define as accurately the material studied. The main purpose of this paper was to identify the maximum values of the strain developed at the point of contact on the surface of the biodegradable alloys. This value was subsequently used to determine the limit values, for the practical use of these biodegradable alloys.
Mechanical properties determination for a hybrid sandwich bar reinforced with steel wire mesh
Authors: Rădoi A I , Miriţoiu C M , Bogdan M , Bolcu A , Geonea I
Published: December 2020

In this paper, some new original hybrid sandwich beams were built in this way: the core is made with polypropylene honeycomb and the reinforcement is made with steel wire mesh. The connection between the reinforcement and the core was made with epoxy resin. The aim of this study is to create a beam from classic materials but combined in a way to obtain a new and original structure. The static experimental conditions are characterized by bending loading of the beams and the determination of statically stiffness. The dynamic parameters were determined from the beams free vibrations. The next experimental montage was used: the beams were clamped at one end and were left free at the other end. At the free end, a Bruel&Kjaer accelerometer with 0.04 pC/ms−2 sensitivity was placed. A force was applied at the free end to bend the beams and after bending, the force was cancelled and the beams were left to freely vibrate. From the free vibrations recording, the next mechanical parameters were determined: the eigenfrequency of the first eigenmode, the damping factors per unit mass and per unit length, the loss factor, the dynamic stiffness and the dynamic Young modulus.
Ecological process for depositing thin layers with high tribology resistance for reconditioning the hydraulic turbines
Authors: Tugui C A , Vizureanu P , Danila N A , Perju M C. , Burduhos-Nergis D P
Published: December 2020

Plasma thin-film deposition can be used to refurbish hydraulic turbine assemblies and subassemblies. In the case of reconditioning by the plasma jet deposition method, one or more plasma jet passes may be carried-out over the worn surface until the gaps achieved by the effect of the hydro-abrasive wear are filled with the depositing material. This paper presents the results obtained at the hardness tests of the thin layers deposited by plasma jet with powders based on Nickel and Boron (Deloro 60). Also, the adhesion of the multiple layers to the base material as well as the adhesion between the layers and the defects that appear on its separation surface were studied. The samples were also analysed from the point of view of the chemical composition by EDX probe and structurally by optical and electron microscopy Vickers-type micro-hardness tests were performed to determine the micro-hardness of the base material and the deposited layer. The VEGA II LMH electron microscope (TESCAN) with TAX QX2 EDX module was used to determine the material structure. The samples were obtained by the method of spraying in mesh spray with Ni powder. By this type of deposition, an easy method of obtaining and rectifying the blades of the hydraulic turbines is obtained with aims to harden the turbine’s blades, in order to increase the wear resistance without affecting the corrosion resistance.
A state of the art of predictive maintenance techniques
Authors: Coandă P , Avram M , Constantin V
Published: December 2020

Nowadays in industry there is a great and increasing demand in resource management, taking into consideration the ever-growing complexity of technical systems. The concept of maintenance is one the most important topics of product development today. As the factories and the industry evolves, the need of proper maintenance plays a major factor in cost and efficiency optimization. In this paper a state of the art of maintenance techniques is presented, predictive maintenance being one of the biggest topics going forward. Predictive maintenance techniques are discussed and presented in detail creating the necessary links with nowadays industry advances: Industry 4.0.
Appraisal of gear pitting severity by vibration signal analysis
Authors: Geröcs A , Korka Z I , Bloju A V , Sfetcu C R
Published: December 2020

Gears are mechanical components used to transfer power between two machines and to modify the operating speed. When they are operating at high loads and speeds the gear teeth surfaces are subjected to loads, which, even in proper lubrication conditions, are leading to failures like scuffing, scoring, spalling or pitting. As the vibration of a gearbox is carrying the signature of the gear faults, these deficiencies may be detected by measuring and analysing the vibration signal. In this research, experimental investigations were accomplished in order to evaluate the gear pitting severity by means of vibration signal measurement and analysis. Thus, four pinions with different pitting grades, created by artificial means, where incorporated in a single helical gearbox and tested on an open-energy test rig. The collected vibration measurements have provided the information regarding the pitting severity, supplying information for the assessment of the gears failure stage. For processing the signals a relative new technique was used, namely the Sideband Energy Ratio™ (SER).
Design, tuning and evaluation of a stand-alone nitinol based thermomechanical actuator driver with a closed-loop position control system
Authors: Popescu Nicolae
Published: December 2020

Nitinol based actuators can be used in many applications. Many of them are simple logic-type applications where intermediate positions or contractions are not required. For such applications, a simple current limiting circuit with enable function can be used. The biggest problem is when we want to use the actuator for positioning applications. In this case, by simply adjusting the current flowing through the nitinol wire is not going to solve the problem. On one hand, the range where we can adjust the current is very small. On the other hand, the hysteresis and thermal inertia are involved in the process. The last and the worst thing is the ambient temperature that will vary in a random way. As a conclusion, the author’s original research for a dedicated driver with position feedback did the job done, eliminating all the related problems. Finally, the driver was implemented, tuned for the mechanical test jig and evaluated under rough conditions in order to prove that the driver can reject the external disturbances. Furthermore, unlike a traditional on/off driver, the designed driver can prolong the lifetime of the actuator by keeping the actuator current at a safe level even in saturation conditions and, by limiting the maximum rate of change of the temperature, thermal shocks can be avoided.
Dismantling strategy for capacitors placed on printed circuits boards: challenges and preliminary results
Authors: Cazan S , Chirita D , Stamate C , Irimia D , Burlacu A , Doroftei I
Published: December 2020

The present paper describes the challenges and preliminary results obtained during the design and implementation of a disassembly system for capacitors placed on printed circuits boards. This research is included in an attempt to reduce the impact of the electronic waste. The proposed architecture includes a six axis multipurpose industrial robot, dedicated sensors and a custom built tool. An originally designed rotary tool, with a specific type of drill bit, was used to dismantle each capacitor on the board. A sensor triggers the tool for the drill rotation when the perforation is accomplished accordingly, so that the friction force is big enough to initiate the dismantling procedure. Using the rotation movement of the drill, at a calculated number of rotations, the capacitors are successfully dismantled from the printed circuits board. An artificial vision system composed from a stereo camera and an image-processing algorithm, provides data with regard to the position of each capacitor on the printed circuit board. A vacuum cleaner was integrated in the scheme to recover the capacitors after dismantling. The scheme design was perpetually optimized using dedicated simulation software. Also, preliminary results obtained on the physical system underline the potential advantages of the proposed approach.
Modeling and analysis of some planar deployable mechanisms. Part 1: translational bar mechanisms
Authors: Doroftei I A , Bujoreanu C , Doroftei I
Published: December 2020

Deployable structures can change their shape and volume in order to dynamic answering to changing needs. Depending on how the transformation is doing, transformable structures can be deployable or demountable, as a kit-parts system. These structures can be classified in four main groups: structures based on spatial articulated bar mechanisms; foldable plate structures; tensegrity structures; and membrane structures. In this paper, some general geometric design aspects of deployable bar structures are discussed and some translational bar mechanisms for deployable structures are proposed. More results on the geometric design, dimensional synthesis and simulation of these scissor structural mechanisms will be presented in future work.
Aspects regarding the development of a gripper with variable geometry
Authors: Grosz E A , Lapusan C , Brisan C
Published: December 2020

In recent years robotics is constantly changing, adapting to the needs of the industry and therefore lately the design of gripping devices is also in a continuous process of development, adaptation, discovery of new ways to catch and manipulate an object and therefore different constructive models have been made. The main purpose of the paper is to present the design of a gripper with variable geometry intended to be used for the purpose of industrial handling.
Mathematical modelling of a search and rescue robot with TriSTAR locomotion units
Authors: Gyarmati M , Tătar M O
Published: December 2020

In this paper the authors present the mathematical model of a search and rescue robot with hybrid locomotion system. The robot uses a locomotion system with two TriSTAR units and two conventional wheels. Details are also presented regarding the design of the robot and the TriSTAR locomotion unit, the robot locomotion and the robot actuation and control.
Aspects regarding the traumatology of the foot in the body jumping
Authors: Merticaru E , Budescu E
Published: December 2020

The aim of this paper is to make the connection between the forces in the lateral ligaments of the ankle joint and in the Achilles tendon, with the forces of ground reaction, for the vertical jump with landing on one foot or both. The fall is experimental analyzed, on a platform of force, when the contact of the foot on the platform is on the whole sole of the foot or on an edge, outer or inner. The ligaments of the ankle joint for which the forces are determined are the deltoid ligament and the calcaneo-fibular ligament. These ligaments are subjected to high forces when the fall on one leg, from a jump, takes place on one edge of the sole of the foot. In this case there is the possibility of ligament rupture, so an analysis and a mathematical simulation can highlight situations that could cause trauma. The paper is a continuation of previous research by the authors in which the forces in the mentioned lateral ligaments and in the Achilles tendon were determined, based on a biomechanical model.
Robotic applications on agricultural industry. A review
Authors: Morar C A , Doroftei I A , Doroftei I , Hagan M G
Published: December 2020

In this paper we aim to present an evolution of the development of robotic end effectors with applications in fruit and vegetable harvesting but without exhaustively covering all technical solutions. This study is focused on robotic final effectors dedicated to harvesting fruits that have reached an advanced stage of development for apples, tomatoes, sweet peppers and cucumbers. The performances of these final effectors (harvesting speed, success rate, costs, etc.) are compared with the performances of human operators and we could say that so far the robots fail to reach the efficiency of human operators in the harvesting processes. The success rate is below 90% and the harvest times are longer than 10 seconds and this means a low efficiency. Although the level of commercial robots for fruit harvesting has not been reached, technological developments indicate an improvement in the performance of this category of robots, an increasing number of research projects are focused on tomato and apple harvesting technologies.
Virtual and experimental device for hip revision prostheses testing
Authors: Popa D L , Calin D C , Buciu G
Published: December 2020

Coxofemoral osteoarthritis is a common pathology, especially for the elderly or for certain social categories. One solution to this medical problem is the hip joint prosthesis. This, however, over time, can lead to joint damage, and obviously a revision of the prosthesis is required. The revision hip prosthesis presents additional mechanical elements and obviously different surgical techniques are required compared to the normal hip prosthesis. There are several methods of prosthesis and obviously more surgical techniques. We were interested to identify that revision method that retains as much bone material, and which has the same mechanical strength. A special device designed to test the revision hip prosthesis was designed and made using a cow's pelvis as bone material. The orthopedic assembly is attached to the device and supposed to a progressive loading until it mechanically fails. The orthopedic system was analyzed with a microscope where the cracks that determined the mechanical failure of the orthopedic system were detected and measured. In parallel, the same device is loaded into a virtual test environment and subjected to a similar load. The actual results and those obtained in the virtual environment were compared and analyzed. Finally, interesting conclusions were drawn.
A virtual approach to orthopedic systems based on implants and prostheses
Authors: Popa D L , Iliuta D , Petrovici I L
Published: December 2020

In the parameterized virtual environments almost all the joints in the human body have been defined. The geometric models of the bone components were generated from different tomographic images taken from many patients. A revolutionary technique was used to identify the different tissues in the human body, based on the specific shades of gray. Special CAD techniques and specific three-dimensional scanning methods were used whereby the initial “point cloud” was transformed into virtual solids. But, this database, which consists of the joint geometries, can be considered ideal, because the pathology is different for each patient. Different pathological situations were created on these ideal models, which required elements of implant or prosthesis. The surgical techniques specific to each pathological situation were considered, so that the bone components were virtually prepared for virtual prosthesis or implantation. The virtual prosthetic joint was tested using the finite element method for different loads determined under normal situations. These results were compared with those obtained in the normal joint. Finally, different conclusions were pointed out.
Researches on the distribution of stresses in a wall girder with geometrical discontinuities
Authors: Atanasiu C , Sorohan Şt
Published: December 2020

The paper presents the results of the numerical and experimental analysis of the stress distribution in a wall beam with geometrical discontinuities subjected to flexural bending. These discontinuities are represented by five circular holes arranged symmetrically with respect to the longitudinal axis of the beam. The numerical analysis was performed with the finite element method and the experimental investigation by electrical strain gauge. The finite element method applied in 2D and 3D for the case of hollow wall beams confirms that Bernoulli's assumption and the hypothesis regarding the variation of stresses on beam height made in the strength of the materials in the beam calculation cannot be used in this case. The results obtained with the finite element method and the experimental ones with the electrical strain gauge method are presented and their comparison is made. The contribution of the experimental research to the selection of a model as close as possible to the practical reality is emphasized. The results of the research allow to draw conclusions about how to position the electrical transducers on the wall beam at the chosen analysis points and its influence on the stress distribution.
Influence of wear on the distribution of pressure and the state of tension at wheel-rail interface
Authors: Blanari I , Goanţă V , Alexandrov M , Morăraş C
Published: December 2020

Since no effective experimental approaches have been proposed to assess state of stress and distribution of pressures at the wheel and rail contact interface to date, numerical calculation methods are known as an alternative to approximate modelling of wheel-rail interaction. In this paper, a numerical procedure is proposed based on the finite element method of the complex tensions state on wheel-rail contact. This study includes the distribution of pressures and tensions on wheel-rail contact system with new and worn profiles, using a finite element modeling (FEM). Using a model of isotropic elastic-plastic material was obtained a FE model that can obtain the distribution of pressures and tensions at the wheel-rail interface for the real surfaces that are in contact, this model is necessary for any tribological study that requires data on the state of stress and pressure only by introducing input data: geometric characteristics, Young’s Modulus, Poisson’s Ratio, Tangent Modulus, Yield Strength, load on the wheel, lateral shift of wheelset.
The stress raisers effect on the fatigue safety coefficients
Authors: Goanta V , Mares M , Cretu P
Published: December 2020

The fatigue limits of metallic materials may be established using their limit cycle diagrams, for various values of stress ratio. On the other hand, the level of actual mechanical stresses in a certain component is taken into account, together with the possible existence of some stress raisers on it, in order to establish (using the schematic limit cycle diagrams) the component safety coefficients in operation. The limit cycle diagrams are plotted in a σa-σm coordinate axis system, i.e. the stress amplitude versus the mean stress graphical representation; any single point on this graph is corresponding to a specific fluctuating stress cycle. Its point of intersection with the abscissa axis (the σm value for σa = 0) represents a stress limit of the component material, from its stress-strain curve in static tensile test, namely σUTS (the ultimate tensile strength) – for predominantly brittle materials, and respectively σy (the yield stress) – for ductile ones. When representing a limit cycle diagram, for a component with some stress raisers in its structure, the possible influence of stress raisers on the above mentioned static stress limits values should be considered. The present paper describes a practical method for determining the fatigue safety coefficients, for a certain component, using the schematic Serensen limit cycle diagram, and considering the stress raisers influence on the static stress limits values.
Compression behaviour study for glass fiberglass-reinforced plastics used in the construction of wind turbine blades
Authors: Morăraş C , Leitoiu B , Blanari I , Andrusca L
Published: December 2020

Classical materials of whose manufacturing requires high energy consumption have begun to be replaced by composite materials, as a better alternative to energy and environmental problems caused by the production of the classic ones. The design of blades with a high efficiency that are resistant and having deformations within the allowable limits and a mass as small as possible is not a simple problem. Currently, the use of composite materials in the construction of blades is a perfect solution but determining the structure with optimal strength requires finding a compromise between the strength limits of materials and costs. In the assembly of a wind turbine, the critical component is the blade and thus the material for the construction of wind turbine blade (WTB) must have high rigidity, fatigue strength, low weight, and good wear resistance. This paper presents the results obtained at compression on the glass fibre reinforced plastics (GFRP) composite, used in the construction of turbine blades. To increase service life and to investigate defects during operation, compression tests have been performed to determine the mechanical properties of [0°/90°] and [±45°] reinforced specimens in accordance with ASTM D3410.
Virtual model of the SES solution for extending the vehicles electric propulsion system autonomy
Authors: Ciobotar C C , Gaidur M , Pascal I , Rakosi E , Talif S , Manolache Gh
Published: December 2020

With the support of advanced technical software one can easily and virtually create and study the SES system (Secondary Energy System - presented in a previous paper), in order to determine if its physical realization is appropriate. In the virtual analyzing and testing mode is much easier in terms of time, costs and resources needed to set up the system in practice. In order to carry out the virtual analysis and testing of the SES system, we used the Catia application for the three-dimensional design and the Matlab numerical computing environment for the theoretical-functional analysis of the system.
Analytical study regarding the topological optimization of an internal combustion engine piston
Authors: Gaidur M , Pascal I , Ciobotar C C , Rakosi E , Manolache Gh , Talif S , Nazare M
Published: December 2020

Continuous progress in the automotive field involves the use of new working methods in the calculation and optimization of the internal combustion engine parts. On this occasion, in this paper, the impact of a topological optimization on the piston in the combustion engine of the conventional or hybrid electric car was studied. Starting from the simulation of the Otto cycle, the dimensional calculation is reached, after which a classical FEA analysis is carried out in order to establish the reference values. In the last part, the data of the classical analysis are compared with those of the topological analysis in order to perform a comparison of their results. The purpose of this study is to reduce the volume of the optimized part and to increase its rigidity.
Applying FMEA methodology to evaluate different shapes of car struts
Authors: Maftei A , Dontu A I , Barsanescu D P
Published: December 2020

The automotive industry is forever growing and leading the world of research and development on a large number of fields; thus, quality assurance and functional safety are two of the main interest in today’s automotive world. The Failure Mode and Effect Analysis method is used according to ISO 26262 to enhance the product quality. Applying methodology learned from the FMEA standard one can compare different variants of the prototype from an early stage of concept and decide which design features will best suit the intended requirements of the system. The method used is comparing a few types of car struts design, but it's not limited only to design, manufacturing and material being also brought in discussion and compared. All in the end the method has applicability for the early stage of the product, if it's conducted with responsibility and documented accordingly.
Redundancy in the control of a gas turbine for naval applications
Authors: Niculescu F , Savescu A , Vasile M L
Published: December 2020

The gas turbine used in marine propulsion for increased efficiency and safety and with a very good power / weight ratio, have a control system that provides alarm, monitoring and control functions, including over-speed protection. The paper presents the inclusion of redundancy in the control of the gas turbine so that it works under optimum operating conditions under any regime. The authors' contribution consisted in the elaboration of control schemes so as to ensure a redundancy of the gas turbine control in case the main control module fails. The analysis of the gas turbine construction led to the elaboration of the hardware structure of the system, based on the doubling of the fuel and speed controls as well as of the related transducers by the gas turbine manufacturer. This redundancy is ensured by the introduction of an additional control module that ensures minimal functionality until the status of the main module is restored. The operation of the two modules, the basic one and the redundant one, are ensured on the basis of software, designed by the authors of the paper. The implemented program also limits the size of the variation, keeping the turbines in a correct operating mode.
Modeling and simulating the activities in an automobile repair shop using ARENA software – part 2
Authors: Radulescu I , Tociu A C , Radulescu A V
Published: December 2020

Statistical data obtained from previous paper are collected and studied for the modeling, simulating and optimization of repair shop activities, for the time, capacity and management performance improvement. Based on the simulation’s results, there are made interpretations and proposals are obtained for the human resources rearrangement, to optimize the automobile repair shop’s overall efficiency, performance and capacity. After running the simulation, there are obtained improvements in the number of serviced vehicles covered by “Maintenance”, “Minor repairs”, “Major repairs, Bodywork and Dye-works” and “Bodywork and Dye-works” categories. Also, improvements are made in the duration for the interventions in “Minor repairs, Bodywork and Dye-works”, “Major repairs”, “Major repairs, Bodywork and Dye-works” and “Bodywork and Dye-works” categories, with problematic intervention duration in the initial simulation. The differences between the initial and the optimized simulation, regarding the length of the station’s queue shows the improvements to follow for a more balanced workload distribution and usage of resources. Such simulations can and do significantly improve the way a business performs in the market and serves its customers. Such tools as the Arena software provide insight into the process flow model and can serve as a theoretical testbed for any proposed improvements.