bluuebunny/crossref_metadata_2025 huggingface dataset:
An optimised state‐of‐charge balance control strategy for distributed energy storage units in islanded DC microgrid
Authors: Mi Yang , Ma Yuchen , Yu Si , Cai Pengcheng , Ji Liang , Fu Yang , Yue Dong , Jin Chi , Wang Peng
Published: December 2020

The optimised droop control method is proposed to achieve the state‐of‐charge (SoC) balance among parallel‐connected distributed energy storage units in islanded DC microgrid, which considers the difference of line impedance, initial state‐of‐charge values and capacities among distributed energy storage units. Since the droop control is the basic control strategy for load sharing in DC microgrid applications, however, the load sharing accuracy is degraded under conventional droop control method due to the unmatched line impedance in reality. Meanwhile, the initial state‐of‐charge values and capacities of each distributed energy storage unit are usually different. Hence, the state of charge for distributed energy storage units cannot be balanced. In order to prolong the lifetime of the distributed energy storage units and avoid the overuse of a certain distributed energy storage unit, the optimised droop control strategy based on sample and holder is designed, by modifying the droop coefficient adaptively, the accurate load sharing and balanced state of charge among distributed energy storage units are both obtained. Finally, the performance of the proposed control scheme is accessed through a series cases on technologies real‐time digital simulator (RTDS) and its effectiveness is verified.
Non‐invasive measurement of intensive power‐frequency electric field using a LiNbO3‐integrated optical waveguide sensor
Authors: Zhang Jiahong , Yang Li , Li Yingna
Published: December 2020

A LiNbO3‐integrated optical waveguide sensor with segmented shielding electrode are designed, fabricated and experimentally investigated. The segmented shielding electrode is designed to improve the sensor response at low frequency and simultaneously to have a larger half‐wave electric field. The minimum and maximum detectable power‐frequency electric fields of the sensor with 10 electrode elements in the time domain are 600 V/m and 139.8 kV/m, respectively, which results in a linear dynamic range of 47.3 dB. The minimum detectable electric field of the sensor with four electrode elements is 5.7 kV/m, while the maximum electric field that can be detected is more than 240 kV/m. By applying the 1.2/50 s lightning electromagnetic pulse, the frequency response of the sensor is calculated from DC to 200 kHz with variations of less than ±2 dB. All these results investigate that such sensor has potential capability to become a portable instrument for the non‐invasive measurement of intensive power‐frequency electric field in high‐voltage power system.
Obstacles to effective participation of civil society organizations in Nigerian extractive industry transparency initiative
Authors: Obuka Uju Beatrice , Adibe Emeka , Alozie Onyedikachi Josiah , Nwafor Morning-Glory , Agu Helen , Chime Ike , Umoh Patrick , Oguejiofor Obinne , Nwafor Ndubuisi , Abutu Paul
Published: December 2020

The extractive industry is essential to the economic development of Nigeria. Accordingly, section 6 of Nigerian Extractive Industry Transparency Initiative Act 2007provides for a stakeholders forum called National Stakeholders Working Group of which Civil Society Organizations are involved. But the participation of civil society organizations in this forum has not been effective. Using doctrinal approach, the paper analyses the roles of civil society organizations as stakeholder representative in Nigerian Extractive Industry Transparency Initiative. It seeks to identify the obstacles hindering their effective participation. The paper finds that problems ranging from lack of cooperation among the civil society organizations, politicization of their appointments by the President into the forum and other issues act as hindrances to their effective participation in the National Stakeholders Working Group. It is suggested that section 6 of Nigerian Extractive Industry Transparency Initiative Act be amended to give civil society organization the freedom to appoint a representative into the forum while they are encouraged to develop a better synergy amongst them.
Design and Analysis of Filler Slab
Authors: Mahananda R K , Mendi Vikas , Raveesh R M
Published: December 2020

Filler slab technology is an innovative and cost effective technology where the dead load of slab is reduced by replacing the concrete with filler material. The concept behind the use of filler-slab technology is to reduce a substantial portion of concrete in the tension zone, since all the concrete in the tension zone does not contribute to the tensile properties. This concrete is replaced with lightweight, inert and inexpensive filler without compromising with the quality and structural stability of the structure. Two-way slab is designed; the filler blocks are placed between the reinforcement spacing by providing a cover of 20mm. The filler materials are granite dust and foundry sand. This filler slab is analyzed using STAAD.Pro and ANSYS software. Filler slab is compared with the conventional slab of same size. This study describes the Structural behavior and cost effectiveness of filler slab when compared to the standard slab.
Analysis of Traffic Congestion Impacts of Urban Road Network under Indian Condition
Authors: Samal S R , Gireesh Kumar P , Cyril Santhosh J , Santhakumar M
Published: December 2020

Traffic congestion has been an area of major bother across the globe. The existing infrastructure is not able to cope with the new traffic demand. Furthermore the restriction of the space and outside activities influencing the traffic congestion. The emerging country like India, where the traffic conditions comprise heterogeneous traffic with no lane discipline, further creates more complicated scenarios for the researcher. A substantial portion of working hours is getting wasted on the roads because of traffic congestion, which imposes the negative effect on the overall economy. There has been numerous of literature and studies for analysis of the traffic congestion and its impacts. However, the result has not been much satisfying. In the present study congestion forecast is aimed under mixed traffic with no lane discipline towards identifying the inherent viability of the diversified traffic situation and presents better recommendations in controlling and evading these prolonged traffic jams. The urban highway systems were considered as a study area. Required particulars were collected by a License Plate Matching method using video graphic survey for the day rush timing considered from 8:00 AM to 10:00 AM and off peak hours to estimate the travel time of a distinct class of motorized vehicles for selected sections of the urban roadway. Congestion indices for both the up and down traffic of a particular road were evaluated from the data collected from the video recording. Traffic congestion impacts were analyzed and possible mitigation measures have been suggested. The study mainly focused on traffic jam indices with regarded to travel time reliability measures to observe the functional effectiveness of the urban road network.
Case Study and Analysis of Ecological Restoration Plan of Lakes in Coimbatore
Authors: Natarajan M , Johnpaul V , Sindhu R , Jayalakshmi K
Published: December 2020

Lakes provide both humans and animals with great interest in water conservation because it contributes to their survival. Lakes have many applications, including leisure purposes, related to human activities. The lakes in India need to be protected and restored directly. Owing to unsustainable human activity, much of the lake landscape is a waste water collection storage area. Given this troubling failure of urban water bodies to function, it is essential that the lakes are kept free of pollution and accessible. The proposed work aims to advance the conservation of urban water systems in Coimbatore. The case study on lake rehabilitation (Periyakulam and Valankulam Lake) was examined. The approval and cooperation by Coimbatore City Corporations enhanced the hygienic condition and the ecosystem of the lakes in and around Coimbatore City. As a result, various approaches for restoring water bodies have been suggested.
An Experimental Study on Rehabilitation of Concrete Beam
Authors: Sindhu R , Johnpaul V , Sunil Gulab Singh , Subash P , Sohail Ahamed Z
Published: December 2020

The theoretical work explains the structural behaviour of a beam reinforced with Aramid warp on repaired structures with its advantages and disadvantages. The final flexural potential of the AFRP is estimated. Experiments were performed to establish the distribution of load-deflection cracks and the width of cracks of the beams. In this work, four numbers of standard beams of the size 1500x150x100 mm are cast with the main rod diameter of 8 mm and a stirrup diameter of 8 mm with a spacing of 150 mm. After curing, the deflection is measured, and the beams under deflected condition are then wrapped in aramid fibre to improve the strength after a deflection by the epoxy resin coated on the surface. It is checked to verify the increased load capacity and is compared to the traditional beam. The result analogy is studied for the reinforcement of the Aramid fibre with the standard beam.
A Comparative Study on Various Stages of Level of Details in Advanced 3D Building Construction Using BIM Tools
Authors: Tejaswini V , Kesava Rao P , Jaya Shankar G , Nagaraja R , Sinha S K
Published: December 2020

Building Information Modelling is one of the most emerging technologies that provide productivity, efficiency and compliance in the construction industry. There are various platforms on which the 3D buildings can be created with large viewing capabilities. The current paper concentrates not only on the construction of 3D buildings with extrusions but also compares the various levels of details in two different BIM based 3D softwares namely ESRI City Engine and Revit Architecture. A 3D building object can be represented basically with four LOD levels at each stage of the building construction. The focal point of the current study also reflects the creation of building interiors and their corresponding attribute information to each element of the building. In City Engine software developed by ESRI, CGA codes are modified and customized to enhance the advancement in the building construction such as generation of building mass, segments, Roofs, Facade Creation, and other Architectural elements. These basic blocks of the building are produced by using Rule based pseudo codes in City Engine. The study illustrates a sample building and incorporates these codes to generate the 3D Building and the interiors are designed with more detailed components in Revit software. Hence, BIM is a path that provides effective monitoring, coordination and collaboration in construction field.
A Study on the Consolidation and Permeability Behaviour of Soils of State of Tamil Nadu, India
Authors: Jayalekshmi S , Elamathi V
Published: December 2020

In order to study the consolidation behavior, clay soil samples from 20 various locations of Tamil Nadu, India were collected and subjected to one dimensional consolidation tests. Coefficient of consolidation cv, coefficient of volume change mv, and coefficient of permeability k were plotted against consolidation pressureσfor all the soils. The results showed that the variation of cv with pressureσis not constant for all the soils. It was observed that various soils have shown various trends. Hence, the trends obtained in the study were compared with the literature. From the study, it was found that the variations in the trends were due to mineralogical effects. The consolidation behavior of soil is found to be influenced by clay mineralogy. Similarly k-σ, mv-σtrends were also compared. The study shows that clay mineralogy has reasonable effects on the consolidation and permeability behavior of soil.
Flexural Behavior of Quaternary Blended Fiber Reinforced Self Compacting Concrete Slabs Using Mineral Admixtures
Authors: Lakshmi Devi G Sree , Srinivasa Rao Dr P
Published: December 2020

Greatly used material in the construction industry is concrete in the world environmental concern. The use of SCM’s (Supplementary Cementitious Materials) in concrete is popular in these days and enlarged along with the amassment of concrete industry, due to the discussion of problems associated with the manufacture of cement like taking out of raw material, co2 emission etc. These effects brought pressures to minimize cement consumption by utilization supplemental cementitious materials are Fly ash, Micro Silica, Rice Husk Ash (RHA), GGBS, etc., use of these byproducts facilitates sustainable development at present world scenario. Developing of self-compacting concrete has brought a positive Perception due to several advantages as reduction in pollution of noise due to vibration, decreases in construction time and power consumption through the utilization of supplemental materials. If binder content in concrete is more it leads to environmental impacts. By incorporating maximum cement content with mineral admixtures it improvises properties along with self-compacting concrete. In this Study an experiment made to study the behavior of QBSCC slabs such as Flexural strength, load Vs deflection curves with addition of crimped steel fibers 0%, 0.5%, 1.0%, and 1.5%.
Forecasting Future Traffic Trend by Short-Term Continuous Observation
Authors: Mendi Vikas , Srinivasula Reddy I
Published: December 2020

Annual Average Daily Traffic (AADT) is a key parameter to understand the traffic flow rates, traffic density and to design any highway. Generally, short period observed traffic data mainly depends on that season in which the traffic surveys were conducted, which may be high or low compared to the other seasons. So, the behavior of seasonal variation of traffic must be considered for the AADT analysis. These seasonal variations can be found out using the past recorded data of that selected location. But in the case of a location where the past annual traffic data is not available, an alternative method is required to calculate the seasonal variation of the traffic data. The present study deals with the analysis of seasonal variation factors to estimate the AADT from the fuel sale data collected from the nearby petrol stations at the traffic survey point. This work explains how Annual Average Daily Traffic (AADT) can be estimated from a week’s limited traffic data when there is a scarcity of automatic traffic data collecting systems.
Studies of Concrete Mechanical Properties with Basalt Fibers
Authors: V Biradar Sangmesh , Dileep M Sai , Vijaya Gowri Dr T
Published: December 2020

Current situation of construction industry demands competency in inventing new materials to enhance the mechanical properties of concrete in its strength point of view as well as durability. Basalt fibers are formed due to melting crushed volcanic basalt rock in a single stage phase. These are non-toxic and environmentally safe. Basalt fibers (BF) are highly resistant to heat, and possess insulating properties apart from having an elastic structure. In this context, the present study has been taken up to study the performance of concrete blended with basalt fibers and their influence on mechanical properties of concrete. The Basalt fibers of different proportions 0%, 0.1%, 0.3% and 0.5% in volume of concrete added to M40-grade concrete (BFRC)and tested for compressive strength, tensile strength and bending strengths. The results showed that concrete with 0.3% fibers exhibited maximum strength values.
Laboratory Evaluation of Engineering and Strength Properties for Semi Rigid Mixtures
Authors: Sunil S , Naga kumar M S
Published: December 2020

Semi rigid mixture is a unique type of mixture in recent years, which has two components:Open graded bituminous mix and cement mortar grout. In this study, engineering and strength properties of semi rigid mixtures with three selected gradations are investigated. The flowability, compressive strength and flexural strength are identified to measure the optimum cement mortar grout. Meanwhile for Open graded bituminous mix, volumetric analysis, drain down and cantabro abrasion loss tests are carried out for selected gradations by varying binder content to obtain optimum mixture. Further the compressive strength, flexural strength, stability, tensile strength and durability tests are evaluated for the selected gradations of optimised Semi Rigid mixtures. The results showed that cement mortar grout containing cement to M-Sand ratio of 1:1, water-cement ratio of 0.35 with super plasticizer (polycarboxylic ether polymer) dosage of 0.45% resulted in desired flow of 12 seconds, compressive strength and flexural strength of 27 MPa and 3.5 MPa respectively. The optimum binder contents of Open graded bituminous mix for the selected gradations are found to be in the range of 4.5-5.0%. Furthermore the obtained 4.5% binder content in Semi Rigid mixture have higher engineering and strength properties compared to 5.0% binder content .
Study of HSC by Using Fly Ash as Partial Replacement of Cement & Incorporating of Steel Fibers
Authors: Srinivasa Rao Kotharu , Srinivasa Rao Kuppala
Published: December 2020

Concrete is one in all the foremost common building materials used. The current study deals with high strength concrete by adding steel (metallic) fiber material in different volume fractions 0%, 0.3%, 0.6%, 0.9%, 1.2% and 1.5% to strengthen the engineering concrete properties and partial replacement of OPC with fly ash in percentages of 0-25% in various ratios. The specimen’s exposure periods of 7, 28 and 56 days on numerous tests like compressive, flexural and split tensile strengths. The research has focused on mechanical and durability properties of high strength concrete. It was observed that 20% fly ash replacement produces the max compressive strength parameters with 1.2% crimped steel fibers, but, the split tensile and flexural strength of concrete was maximum at 25% fly ash along with 1.5% steel fibers. Furthermore, the durability of concrete has conducted such as acid attack due to HCl and H2SO4. The minimum loss of weight produces at the 25% fly ash is 2.98% and 2.81% by HCl and H2SO4.
Dynamics of steppe arable land in zones of oil fields development (Orenburg region)
Authors: Grudinin D A , Myachina K V
Published: December 2020

The reported paper presents the analysis data on the arable land dynamics in oil extraction zones. The long-term development of oil fields leads inevitably to farmland losses for a variety of destructive processes and, as a consequence, to withdrawal of lands from a turnover, and land abandonment. Our study was carried out on two sample territories in the steppe zone of Orenburg region with two key land utilization sectors – agriculture and long-term oil extraction. To reveal the dynamics of agricultural lands and oil fields we adapted time series of satellite (Landsat) imagery. An analysis was divided into several phases dealing with quantity-related assessment of fields withdrawn from the farmland turnover and tracing the relationship between their position and objects of oil extraction infrastructure. A period of interest covered 40 years – from 1980 to 2020. The research has highlighted a thirteen and eightfold increase of zones with oil production facilities on the first and second territory, respectively. Recently, 24% and 26% oil fields are located on arable lands. Another outcome of the study is that the expansion of territories designated for subsurface use is the reason that both directly abandoned areas and neighboring lands are removed from the farmland turnover. Agricultural lands affected by oil fields are at a high risk of being withdrawn from the turnover – losses may range to the firth of arable lands.
Arctic Reindeer Herding and Ecology: When Economy is Impossible without Safeguarding Ethnocultural Distinctiveness
Authors: Gorbunova A. , Zadorin M. , Kuprikov N. , Saveliev I.
Published: December 2020

The paper considers environmental issues related to the field of agriculture in the Russian Arctic exemplified by the research into statutory regulation of economic, cultural and ecological aspects of reindeer herding by a small-numbered indigenous people called the Nenets. Using the example of the Nenets Autonomous Area, the authors provide insight into the measures implemented to control the deer-feeding capacity of pastures for the purposes of sustainable use. The article gives an estimate as to the promptness of actions taken to prevent the loss of cattle across the Yamal Peninsula due to the spread of Siberian plague. While giving prominence to the successful regional practices of Yakutia, the authors also emphasize the necessity for the introduction of amendments to the Russian legislation regarding the procedure of ethnological expert examination to the extent that it shall include the opinions given by the officials of organizations representing the interests of small-numbered indigenous peoples inhabiting the territory in question. A legislative gap in the above-mentioned field results in emergency measures replacing preventive measures in the face of potential anthropogenic disasters similar to the one which took place in Norilsk in the summer of 2020. One of the authors was born in the Kanin tundra of the Nenets Autonomous Area and represents an indigenous and nomadic Nenets people.
Environmental Improvement of Saline and Alkali Soils in the Kamyshlovskaya Valley and Revival of Natural Grassland Efficiency
Authors: Kuzmin A I , Tusupbekov Zh A , Ryapolova N L , Nadtochiy V S
Published: December 2020

Agricultural use of saline soils is possible only through implementing reclamation measures on their desalinization. The removal of salt from soils is a cost-demanding and time-consuming process. Expenses related to the treatment of saline soils are connected with a desalinization method and include costs of water supply to a saline area and its drainage. A reasonable project cost, as well as efficient water consumption depends on the use of natural environment conditions. The reported paper presents the assessment of water recourses in the drainage area of the valley valley, it is focused on the restoration of water bodies in the Kamyshlovsky log, stabilization of their balance, and environmental improvement; the study suggests economic perspectives of saline and alkali soils. The latter is essential to revive the efficiency of natural grasslands in the valley and its use as a disposal of production and household waste water from surrounding rural settlements.
Formalized model of agricultural insurance development strategy as an element of industry management digitalization
Authors: Zhichkin K , Nosov V , Zhichkina L , Tarakanov A , Zhenzhebir V , Sterlikov F
Published: December 2020

The article discusses the possibilities of agricultural production management digitalization with formalized models, using the example of state support for agricultural insurance. The aim of the study is to adapt the BCG model for use as a tool for designing a development strategy for agricultural insurance with state support. Tasks: - determine the possibilities of using the BCG model to design an agricultural insurance development strategy; - offer a model parameters system; - define a set of strategies in the framework of the goal. Putting the model into practice will make the existing state support system more transparent and predictable, depending mainly on the objectives of state policy and the actual indicators achieved by the industry. At the costs high level offered by these measures, the system involves the creation of a sustainable market for insurance services, regulated by both economic and administrative mechanisms. The presence of such decisions totality will automate the decision-making process at the industry management level; ensure the agricultural policy continuity in the long term.
Development of biotechnology for cultivating Potentilla L. plant material with antivirus and antibacterial activity
Authors: Tikhomirova L I , Zaripova AA
Published: December 2020

The reported paper presents a biotechnology developed to produce phytomass of Potentilla L. species (P. alba, P. fragarioides, P. fruticosa, P. chrisantha, P. longifolia). Regenerative Potentilla plants are good at extracting bio-friendly elements (Pb, Cu, and Zn) from the Murashige and Skoog growth medium and accumulating them.

Water extracts of plant material P. alba, P. fragarioides, P. fruticosa, P. chrisantha, P. longifolia have shown a good biological activity against herpes simplex virus type II. Extracts of bio-technologically produced Potentilla alba plants have demonstrated an antibacterial activity against E. coli, K. pneumoniae, S. typhimurium, St. aureus taken in a minimal dose of 37.5 μg/ml.
Role of metrology inaccuracy for variance of test results under reproducibility conditions
Authors: Zakhakhatnov V.G. , Popov V.M. , Afonkina V.A. , Levinsky V.N.
Published: December 2020

A source of inaccuracy in regression models is supposed to be the statistical nature of a model and metrology inaccuracy related to the measuring explanatory and response variables. A number of approaches to the assessing inaccuracy of regression models are available. However, their use in searching for a solution to engineering problems concerning the assessing multiple regression inaccuracy is restricted by insufficiently developed mathematical tools. When explanatory variables assigned appropriately the inaccuracy of a regression depends on the reproducibility of test results. The reported simulation study investigates the importance of a measurement error to the variance of a normally distributed random variable for small sample sizes between 2 and 30 and coefficients of variation 1, 2, 10, 20, 40, 60. The effect of inaccuracy is analyzed relying on a relative confidence interval of variances estimated as a difference between variance intervals for a variable measured inaccurately and accurately divided by a confidence interval of the variance for an accurately measured variable. The outcomes to emerge from the study are quantity-related estimates for the effect of metrology inaccuracy in the measuring random variables with various coefficients of variation for small sample sizes and different relative measurement errors. For the assessing we use 106 retests and a maximal variance for the same number of repeated tests. The results make possible to evaluate an effect of metrology inaccuracy for diverse coefficients of test results variation, as well as determine an appropriate extent of testing for assigned model inaccuracies and a known measurement error. In addition, practical application of obtained results is shown.
Electrically Energized Comfort Heating System Based on Electric Film Heaters and intended for Post-Weaned Pigs
Authors: Popov V M , Afonkina V A , Epishkov E N
Published: December 2020

The reported paper summarizes outcomes of the thesis “Electrically energized comfort heating system intended for pre-nursery pigs kept in an unheated sow house” [2]. This alternative method of keeping warm pre-nursery pigs has been proven to be efficient both in the pilot phase and in pilot batch production. The further research aimed at the application of this system to the keeping warm pre-weaned pigs. The paper describes and presents a calculation procedure for parameters of a comfort heating system based on film heaters and intended for pre-weaned pigs.
Future development of transport and environment
Authors: Rudneva S.E.
Published: December 2020

The reported paper discusses co-existence aspects of an evolving transport infrastructure and the environment. In a long-term perspective, the specific development and upgrade of various transport means shouldn’t cause harm to the environment. The paper highlights a necessity of environmental improvement, reduction of noise impact, vibration and hazardous emissions into the atmosphere.
Formation of a digital transformation system for the transport complex
Authors: Tolkachev S A , Morkovkin D E , Shcherbachenko P S , Gibadullin A A , Bykov A A
Published: December 2020

The presented study is devoted to assessing the level of digital development of organizations and the formation of a digital transformation system for the transport complex. The digital transformation of the transport complex is considered in the framework of the concept of the cyclic sequence of the spread of basic technologies in the economy, in accordance with which the full-scale deployment of the “transport” technological structure is predicted within the framework of the third mega technological cycle in the middle of the 21st century. The study analyzed indicators reflecting the level of digital development of organizations, transport companies and the amount of data protection tools used. Because of the analysis, it was revealed that in general, organizations have a high share of digitalization, but they are significantly lower in organizations of the transport complex, while about a third of organizations do not use data protection technologies. The study proposed a model for providing digital transformation of the transport complex, containing the types of activities that should be involved in digital transformation, the potential used for digital transformation and tools for digital transformation of the transport complex. In conclusion, conclusions were drawn from the results of the study.
A model of the effect of dry friction on the behaviour of a dynamical system
Authors: Ciornei F-C , Alaci S , Bujoreanu C
Published: December 2020

A dynamical system with one degree of freedom is modelled in two manners: the first one considers that only the dynamical sliding friction is present and the second considers the presence of both dynamic friction and static friction. It is difficult to apply the model of revealed static friction only for the zero relative velocity. For this reason, an approximate model for the static friction was identified, that accepts that the static friction occurs when the magnitude of relative velocity in contact decreases under a certain value, the critical value. The integration of the equations of motion of the two models reveals that for important values of the relative velocity, the two models estimate the same behaviour of the system. An experimental set-up was used to validate the theoretical results.
Reconfigurable multilayers architecture used as electromagnetic sensor
Authors: Iftimie N , Steigmann R , Dobrescu G S , Danila N A , Stanciu M D , Faktorova D , Savin A
Published: December 2020

The models designed CAD/CAM were loaded into the simulator to analyze the characteristics of the experimental devices attached. The array of sensors with unconventional architecture with reconfigurable unit cells (UCs) was topologically optimized, establishing the opening angle of the cell, the active surface, the geometry of the structure of the areas starting from the idea that the resonance frequency should be within the range of ISM frequencies. The simulations and determinations of test parameters of UC geometry are used for realization of arrays with reconfigurable shapes having the same aperture angle that can be used as wireless sensors for pressure detection.
Analysis of the collapse mode classification in case of circular tubes
Authors: Predoiu C P , Negrea R F , Tabacu S , Popa D
Published: December 2020

In this paper, the authors present an analysis of the collapse mode of tubes with circular cross-section under axial loads. Considering that requirements related to pollution are becoming more stringent, modern transportation systems require lightweight materials. These materials should have a high degree of protection. To reduce the CO2 emissions value, a vehicle is powered by an engine with a small displacement. Furthermore, to achieve good performances in terms of acceleration and maximum speed, the total mass of the vehicle should be decreased. In case of a collision, this energy is consumed, mainly, by controlled deformation of the sacrificial structures. During an impact, the dimensions of the cockpit must not change. The same time is necessary to obtain a minimal acceleration to ensure the health of the passengers. This requirement is not compatible with a rigid structure and leads to a high acceleration level. Sacrificial structures are defined by tubes with closed profiles. Studies related to thin-walled structures with the circular cross-section under axial loads have a strong background in the work of Guillow and Andrews. The paper proposes to add complemental information these charts for another type of material, and the result obtained are correlated with the limits from the other studies existing. The research is focused on the structures with the height correlated to the structures used in the automotive industry. The analysis of global buckling for the tall structures is completed by a theoretical evaluation using Euler’s equation.
Deriving patterns for the vibration-based damage detection in side frames of bogies
Authors: Barbinta C I , Gillich G R , Nedelcu D , Manescu T
Published: December 2020

Detecting damage in the incipient state is of crucial importance in monitoring the health of engineering structures. Approaching damage detection as an inverse problem is a common method when vibration-based techniques are used. It implies a precise a priori estimation of the modal parameters. We present in this paper a model to predict the frequency changes due to cracks in the side frames of bogies used to detect the welding defects in T-joints. To this aim, we model the structure and perform simulations using the SolidWorks software. The frequencies for the first thirteen modes are derived for the intact structure and the structure with different damage lengths and positions. By these tests, we first desire to find the optimal fixing of the side frame to reduce the number of vibration modes that are not of interest to the damage detection process. After finding the ideal fixing system, we derive patterns, for different defects, in the form of relative frequency shifts. Finally, we conclude about the damages that can be identified using the derived patterns, the conclusions being traced based on the measurability of the frequency changes.
Experimental stand for studying the stretch behaviour of woven plastic nets used in the food industry
Authors: Besnea D , Dinu E , Rizescu C , Moraru E , Rizescu D , Baran N , Pascu T , Panait I C
Published: December 2020

Mesh bags are the most modern way of packing, storing and transport used for packing vegetables and a variety of fruits. Mesh bags provide freshness, mechanical ventilation and offers a clear image of the content. Determination of elongation is one of the tests by which the nets used in the food industry must be done before their distribution. The mesh bags are made from recyclable materials, available in different colours and can be inserted into foil strips that provide ample space for images and product information. The products being analysed are polyethylene woven nets for packing vegetables (potatoes, onions, peppers, cabbage, carrots, cucumbers, etc.), fruits (apples, pears, oranges, lemons, nuts, etc.) in a diversified dimensional and coloristic form representing the cheapest and most accessible method of packaging. The authors had concerns in the field developing a series of stands with applications in the food industry.
Determinations regarding the influence on movement and comfort of different elastic suspension structures in N2 type vehicles
Authors: Mitroi M F , Chiru A
Published: December 2020

Modern technologies implemented in the automotive field bring a considerable increase of performance, but also safety at the same time. Moving the vehicle under such conditions also requires a high level of comfort, regardless of the type of road traveled.

The dynamics and behavior of the vehicle are conditioned by its constructive and functional characteristics. The research carried out highlights some aspects regarding the importance of elastomeric elements in the structures destined for shock and vibration damping.

Thus, different solutions adopted are analyzed, for the car's damping system, to reduce the specific disturbance factors of the road. For a vehicle of average load capacity, respectively 5 tonnes, used in determinations, checks are made on the various elastic systems with role in reducing shocks and vibrations. It is also intended that for the solutions adopted, the frequencies and amplitudes of the vibrations will occur at low values. By modeling the systems in AMESim, the aim is to identify the performance of the solutions adopted, as well as the level of comfort obtained.
Researches, studies and development prospects of the quality of metallic parts made on CNC
Authors: Puşcaş (Popescu) N , Tempea I
Published: December 2020

The quality of products is an important economic indicator. The paper presents studies, researches and development of prospects execution of bent metal parts on CNC machines. Through these studies we tried to find answers regarding the quality of products, problems that many companies face. Laborious studies and research proposed for the paper, on determining the drawings of metal parts (the flat plane). The quality and precision of the products, may influenced by the other variables: the vibrations of machines, tool usage, tolerance between the surface of the bending tools, variation of the temperature during the processes of punching and bending, their usage and the roughness of the metal sheet. The calculations of the drawing pieces must include the bending coefficients Kî. The bending coefficient obtanaited for de steel parts (OL 37) with a thickness of 1 mm, was the subject of the present paper. This coefficient Kî depends on: the type of the material, the chemical composition, the degree of complexity and the number of bends, the movement between the piece and punching or bending tools, vibrations of the machines and other variables. The bending coefficient was obtained by experimental tests and measurements.
A novel approach for assessing the instantaneous flow rate of an external gear pump using 3d printing and computer vision
Authors: Sarbu Valerian , Avram Mihai
Published: December 2020

The flow rate ripple inherent in gear pumps is already well researched with varying degrees of accuracy. The usual approach for determining the instantaneous flow rate includes mathematical models, computational fluid dynamics (CFD) and the practical approach, measuring the flow rate on an existing system using sensors. This paper presents an original method for determining the flow rate using new technologies, specifically 3d printing, edge computing and image processing. The target is a 3d printed scale model of the gears and casing attached to a stepper motor; a raspberry pi zero acts as a remote image capture device and position controller. The frames captured at key positions are wirelessly transferred to a computer running MATLAB for processing and extracting the flow data using special algorithms. Results were very good and reasonably accurate.
A new predictive model to estimate the frequencies for beams with branched cracks
Authors: Tufisi C , Gillich G R , Barbinta C I , Nedelcu D , Hamat C O
Published: December 2020

Detecting damage by using vibration signals is popular because it permits evaluating the structural integrity without being necessary scanning of the whole structure. The effect of transverse cracks is presented in detail in the literature, but in reality, the cracks can shift the direction of propagation and even split, resulting in the so-called branched crack. The effect of this type of crack is less investigated due to its complexity. We herein propose a simple model to predict frequency changes that occur due to branched cracks. Initially, we present the effect of stiffness reduction along the damaged section on the structure’s natural frequency. Next, we show that the predicted frequency drop is smaller that happens in reality. This is caused by the sudden cross-section reduction in the slice on which the transverse crack branch is. The phenomenon is similar to the stress concentration for static loads. We propose for dynamic systems a factor that considers the energy stored at the delamination ends. Considering this factor and the stiffness reduction on the damaged segment, we obtain accurate frequency changes due to any type of crack that extends in the longitudinal direction. The model is implemented in Python and tested successfully against simulation with dedicated software.
Design and analysis of a new bicontact cam mechanism
Authors: Alaci S , Ciornei F-C , Buium F
Published: December 2020

Based on an observation from a previous work, the authors use the degree of passive freedom of a mechanism with roller follower to propose a new type of mechanism. In the new mechanism, the roller is replaced by a jointed element that forms two contacts with the cam. The obtaining of the cam profile is the main disadvantage of the cam mechanisms but in the present work, by using a cam formed by two connected discs, it is aimed to be avoided. The method is illustrated by designing the mechanism in CAD software followed by the simulation of its movement. To optimize the movement of the final element, the equivalent mechanism with lower pairs is used which has the advantage that the lengths of the elements are constant. The kinematics of the final element is particularly sensitive to the variation of the dimensions of the mechanism, fact illustrated by an example.
Forces transmission in the case of SSR structural group
Authors: Duca C D , Buium F
Published: December 2020

This paper contains the SSR spatial group analysis, following to determinate the forces transmission index. It comes to conclusion, this index is a two variable function, defined by discrete values and graphically represented by a surface. Knowing this function it has been studied a linkage containing the SSR group – the spatial four bar linkage of orthogonal type. To avoid very high values of reactions, the forces transmission index must be inferior limited. Verifying of this limitation is done by the above mentioned surfaces level curves. This method is performed by authors, and it had been used previously for planar linkages only.
Geometric synthesis of the folding bridge mechanism
Authors: Moise V , Dugaesescu I , Ungureanu L M , Rotaru A
Published: December 2020

In London there is a folding bridge composed of eight platforms articulated between them. One platform is fixed to base (a platform from one end). The platforms have the shape of isosceles trapezoid. When the bridge is folded the large bases of the trapezoids form an octagon. The driving mechanism of the bridge is composed by motor dyads (active RRTaR groups) and RRR dyads. For the eight platform bridge the maximum piston stroke is less than the platform height (trapeze height). In this case, the connections between the hydraulic cylinders and the other elements are usually made, i.e. at the ends of the cylinder. If we want to make a folding bridge with fewer moving platforms, there are situations when the piston stroke is greater than the height of the trapeze. In this case must be performed the geometrical synthesis of the mechanism such that the folded bridge forms desired geometric figures (square, pentagon etc.).
Tower structure optimization through finite element analyses
Authors: Vlădulescu F , Constantinescu D M
Published: December 2020

In this study the objective is to obtain an optimal configuration for an antenna lattice tower which has an imposed height of 30 m. For this purpose, a variable geometric model which considers specific working parameters is created, and a 3D finite element (FE) model is generated by using beam and shell elements for an optimization study. The 3D FE analysis is updated automatically for each variant of the geometric model. The response surface methodology (RSM) is used together with the central composite design (CCD) approach as to optimize the response of the lattice tower. The model of the tower is subject to static and dynamic loadings, including earthquake analysis. A response spectrum analysis based on Rosenblueth's Double Sum Combination (ROSE) is performed because the natural frequencies resulting from the modal analysis have close values. The optimization solution algorithm used for the tower optimization is the nonlinear programming by quadratic Lagrangean (NLPQL), which is based on the gradient algorithm for models with only one objective function and several optimization restrictions. Out of three final candidate design solutions the one which gives the minimum mass is proposed.
Influence of warning lights for intervention vehicles on aerodynamic performance
Authors: Iozsa D , Ilea L , Fratila G
Published: December 2020

In today’s world, the freedom to travel is a daily necessity and part of human rights. This premise is directly linked to transport sector causative of air pollution. While the focus is on heavy transport and passenger vehicles, another important segment is represented by special utility vehicles such as the ones for intervention purposes (police, ambulance, etc.). The mandatory presence of warning lights bars has a big impact in aerodynamic performance and hence, in their emissions. The paper studies the influence of a generic lights bar on sedan, hatchback and SUV body types, in three main roof mounting positions – front, median, rear. Through CFD methods it is found that the most unfavourable case is the front mounted lights bar with 6g up to 12g CO2/km (WLTP conditions). The influence of median and rear mounting position is smaller, but still adds 3g to 7g CO2/km. Using streamlines, pressure and shear forces, future work will focus on optimizing the lights bar shape and size, for a reduced SCx impact in overall performance. This topic is considered very important since main cities (including Bucharest) started taxing or banning high pollution vehicles.
Influence of the flywheel profile on the energy storage capacity of the kers system
Authors: Milica L , Andrei G
Published: December 2020

When speaking about other energy storage devices, flywheels can be viable alternatives due to the low degradation process during the entire operating life, and its numerous energy discharge rates. In this paper, the problem of the flywheel shape, present in the KERS system, is approached analytically. The analysis was performed on three series of rotors and the results were validated using a CAD program. The linear relationship between the mass of the flywheel mass and its rotation axis was emphasized by Pappus-Guldin theorem. Based on the results it was shown that the value of kinetic energy is higher when the mass of the flywheel is concentrated closer to the axis of rotation.
The finite element analysis of pelvic assembly resulted from a pedestrian’s traffic accident. The dynamic analysis
Authors: Pascal I , Ciobotar C C , Gaidur M , Rakosi E , Manolache Gh , Talif S
Published: December 2020

The purpose of this study is to make a series of finite element analyses of the pelvic bone assembly of a pedestrian involved in a car crash. The analyses are of a dynamic type. In this way we took into consideration a normal pelvic bone assembly and an osteoporotic pelvic bone assembly. The conditions for analyses were chosen as to reflect the reality of the situation. With the help of this study the authors want to create a date base which aims to improve the time needed for achieving an accidentology technical expertise.