bluuebunny/crossref_metadata_2025 huggingface dataset:
A new performance test to evaluate the sulfate resistance of concrete by tensile strength measurements
Authors: Feldrappe Volkert , Haufe Johannes , Ehrenberg Andreas , Vollpracht Anya , Matschei Thomas
Published: April 2022

Concrete structures without sufficient durability can be damaged by sulfates in groundwater and from surrounding rock layers. To evaluate the performance of a concrete mixture, precise and performance-oriented test methods are a must. Therefore, a new a performance oriented concrete test procedure based on tensile strength measurements was developed considering experiences reported in international literature and recommendations of state-of-the-art reports. A vast parameter study with approx. 3850 tensile tests on ASTM briquets, 1900 flexural tensile tests on standard prisms and 2100 expansion tests on mortar flat prisms of different ages and with different storage conditions was statistically assessed. Based on the results a performance-oriented test method could be defined which considers not only the chemical, but also the physical resistance of a concrete against sulfate attack. The method was verified by 23 concretes with different cements or cement fly ash combinations and additional field tests. It could clearly be demonstrated that the results represent the performance of a practical concrete in case of sulfate attack. Furthermore, it leads much faster to an evaluation of the sulfate resistance compared to the most other practical oriented methods.
Fundamental properties and durability of slope protection spray mortar reinforced with bamboo fibers
Authors: Fujiyoshi Kazuo , Ueda Takao , Tsukagoshi Masayuki
Published: April 2022

In order to enhance resistance against cracking and durability, short fibers such as steel and organic fibers have been conventionally mixed into spray mortar used for slope protection. In this research, fundamental properties of bamboo-fiber-mixed spray mortar were examined by laboratory tests. The mechanical properties of spray mortar containing bamboo fibers were examined under cyclic wet and dry conditions along with its resistance against freezing and thawing by a spray test. It was confirmed that 0.75% mixture of bamboo fibers in spray mortar most successfully improved mechanical properties and durability. These include adhesion strength to the base surface following exposure to cyclic wet/dry conditions and overall resistance against freezing and thawing. In addition, higher compressive strength and adhesion strength to the base surface were achieved by further mixing in vinylon fibers or fly ash in combination with bamboo fibers.
Benefits of pervious concrete for urbanized habitats
Authors: Giunti Giuseppe , Miczek Daniel
Published: April 2022

Pervious (draining) concrete is a new generation concrete which, for its structure, allows rainwater to enter the subsoil and at the same time is determining the final surface without the need for any additional layer. Pervious concrete allows to drain off up to 95 % of precipitation, which represents a significant contribution to ecology and sustainability. Therefore, its use is particularly suitable in city parks, bike paths, in the vicinity of apartment buildings, swimming pools and parking lots. Rainwater is not purposelessly be drained by the city sewer system, but it is absorbed directly in place and contributing to the environmental improvement of the urban habitat (replenishment of groundwater supplies, water for roots of plants and trees, reduction of the thermal island of the city, etc.). Unlike prefabricated paving blocks (interlocking and flat paving), pervious concrete makes it possible to realize structured and complex shapes of finished surfaces without the need for laborious cutting, waste, dust and with generally faster laying. This paper summarizes the current achievements within the Buzzi Unicem Group and the use of pervious concrete in the Czech and Slovak Republic.
Chloride ion penetration behaviour in concrete containing an expansive additive and a calcium-aluminate-based additive
Authors: Ito Shinya , Iyoda Takeshi
Published: April 2022

The effect of the material characteristics on the infiltration behaviour of chloride ions in concrete containing a combination of an expansive additive and a calcium-aluminate-based additive has been investigated. The same level of salt resistance as that of blast furnace slug cement was exhibited even for a small addition amount. In addition, the permeation behaviour of chloride ions was largely influenced by the immobilisation capacity and pore network. When these changes were dominant, the results suggested that the characteristics based on the Fick diffusion equations may not necessarily reproduce the actual permeation behaviour of chloride ions.
Durability evaluation of surface softened steel bar for prestressed concrete
Authors: Iwanaga Kengo , Mizoguchi Shigeru , Matsumoto Yu , Takai Kenichi , Ichiba Mikiyuki
Published: April 2022

The effects of Si addition and surface softening on delayed fracture susceptibility were evaluated in tempered martensitic steels with tensile strength of 1450 MPa. The delayed fracture susceptibility was reduced when Si content was increased from 0.2 mass% to 1.88 mass%. The delayed fracture susceptibility of steel containing 1.88 mass% Si was reduced further when the tensile strength of its surface was lowered to around 1150MPa. Based on above results, the durability of these steel bars was evaluated by exposure test of prestressed concrete poles (CP). The bending load of the PC pole was 1.3 times of the design load. As a result of dismantling investigation after 10 years exposure test, there were no breakage of the steel bars in the PC poles and the soundness was maintained. In this paper, we will also introduce some comparison results of exposure tests and acceleration tests with aiming to establish the evaluation methods for the long-term durability.
Study for re-ASR behaviour of recycled concrete using ASR generated concrete and considering countermeasure technology
Authors: Iyoda Takeshi , Matsuda Nobuhiro
Published: April 2022

It is predicted that the concrete volume to be discarded will increase due to the renewal of the concrete structures and the increase in the returned concrete from construction site. The use of this concrete block as recycled aggregate is very important in terms of sustainability. However, recycled aggregate concrete is difficult to use due to large problems such as drying shrinkage and freeze-thaw action. On the other hand, the aggregate used for the raw concrete is often unknown, suggesting the danger of ASR. There is no previous research about what kind of danger is caused when an aggregate having an ASR risk is used as a recycled aggregate. Therefore, in this study, recycled aggregate was made from raw concrete where ASR occurred, after that recycled concrete was manufactured using this aggregate. After this, ASR tests were conducted again for the recycled concrete. In addition, we examined whether recycled concrete using aggregates with properties improved by using the previously reported carbonation technique could be an ASR countermeasure technology. As a result, it was found that the recycled concrete using the ASR-generated raw concrete as aggregate can suppress ASR by using recurring ASR aggregate treated by carbonation technology.
Expansion of sustainability in the ACI 318 building code
Authors: Kelley Shana
Published: April 2022

The American Concrete Institute (ACI) has long recognized the growing importance of accounting for environmental sustainability in the design of concrete structures. As the next version of the ACI 318 Building Code is being developed (ACI 318-25), a new sustainability subcommittee, Subcommittee N, has been formed and tasked with expanding the provisions related to sustainability in the code. This paper reviews the current provisions in the ACI 318 Code that are related to sustainability and explores the possible future expansion of code and commentary language to provide better guidance on sustainable design. Areas of focus for expansion of code language, including definitions of sustainability metrics, as well as the defined baseline for comparison, are discussed. While sustainable design is increasingly being specified in concrete projects, the sustainable properties of concrete are often interrelated with other aspects of design, including resiliency and intended lifespan. Approaches to acknowledging the impacts of life cycle considerations on the sustainability of concrete construction are also explored. Finally, the anticipated timeline for the development of ACI 318 sustainability provisions is described, as well as potential interactions with other code writing organizing that are currently developing sustainability provisions.
Extent of corrosion damage for RC structures exposed to chloride-bearing environment
Authors: Lollini Federica
Published: April 2022

In industrialized countries, most of the reinforced concrete (RC) structures and infrastructures have more than 40 years, since they were built around 1960 − 1980, and were designed for a service life of 50 years. Consequently, in the next years, the number of structures and infrastructuresthat will need to be repaired will steeply increase. Several techniques, characterized by a different durability, environmental impact and economic impact, are available for the repair of a reinforced concrete structure damaged by the corrosion of reinforcement. To help the designers in the choice of the most suitable one, a preliminary assessment of the condition of the structure is essential, aimed at diagnosing the causes of deterioration, the extent of damage, i.e. the extent of corroding reinforcement, and its evolution in time. An approach, with a wide consensus, for the evaluation of the extent of corroding reinforcement is available for carbonation-induced corrosion, whilst it is still lacking forchloride-induced corrosion. In this paper two approaches for the evaluation of the extent of corroding reinforcement for a RC structure subject to chloride-induced corrosion are presented and compared, showing similar results. These approaches can be useful to properly plan a restoration intervention as well as to assess the reliability of the recently proposed model for service life design.
High-performance concrete containing waste vitrified tiles
Authors: Mariaková Diana , Fořtová Kristina , Jirkalová Zuzana , Pavlů Tereza , Hájek Petr
Published: April 2022

This contribution deals with the possibility to use waste vitrified tiles (VT) in high-performance concrete. Silica powder normally used in high-performance concrete is replaced by waste vitrified tiles in 25, 50, 75 and 100 %. The basic experiments are tested, such as water absorption, flexural strength and compressive strength. The durability is examined, freeze-thaw resistance is tested in 25, 50, 75 and 100 freeze cycles. The results are evaluated and compared with the reference high-performance concrete, containing silica powder. The recipe of concrete is optimized based on these results.
Sustainable concrete production with recycled concrete wash water beneficiated with CO2
Authors: Monkman Sean , Meyer Vincent
Published: April 2022

A significant amount of wastewater is generated through the cleaning of equipment utilized within the ready mixed concrete production cycle. The reuse of concrete wash water as mix water is limited by the negative material performance impacts associated with the suspended solids; the effects are exacerbated with increasing solids contents and water aging. A novel carbon dioxide treatment to allow the use of high solids wash water (specific gravity 1.10) as mix water was examined. Seven batches of concrete were produced and compared: a reference mix, two batches with untreated wash water and four batches with CO2 treated wash water. The carbon dioxide treatment mineralized CO2 at 28% by mass of the treated solids. Acceptable concrete was produced through adjusting admixtures for workability. The compressive strength at 1, 7, 28 and 56 days was improved relative to both the reference and the concrete produced with untreated wash water. The suspended solids containing mineralized CO2 served as a viable cement replacement. The avoided cement and bound carbon dioxide served to lower the carbon impact of the concrete by about 14%. The approach allows three waste streams (CO2, wash water and wash water solids) to be reused to produce more sustainable concrete.
Interfacial bond behavior of adhesively-bonded timber/cast in situ concrete (wet bond process)
Authors: Nemati Giv Ali , Fu Qiuni , Yan Libo , Kasal Bohumil
Published: April 2022

The goal of this research was to study the strength of the interfacial bond between cast-in-situ concrete and engineered timber (cross-laminated timber (CLT)). Double lap specimens were manufactured using fresh concrete that was cast between two CLT blocks. Polyurethane and epoxy adhesives were used to bond the wet concrete with the CLT blocks. The shear strength of wet-bond specimens was compared with the specimens prepared under dry conditions (prefabricated concrete cube glued to CLT blocks). The statistical analysis (T-test) of bond strength showed that the shear strengths of wet- and dry-bond specimens using epoxy and polyutrthane adhesives were no significantly different for the tested C25 plain concrete and the CLT. The failure mode of dry-bond specimens were concrete failure near the interface, however, debonding at interface was the dominant failure for the wet-bondspecimens.
Thin concrete overlays wit carbon reinforcement on deteriorated concrete pavements
Authors: Neumann Julia , Breitenbücher Rolf
Published: April 2022

In many countries, concrete pavements are normally built as Jointed Plain Concrete Pavements. Due to a lack of alternatives, repairing deteriorated concrete pavements usually requires the replacement of the complete pavement structure and maintaining the joints, which is labour- and resource-intensive. To increase the durability of repairs and to save resources concrete overlays with carbon reinforcement are developed. By the application of non-corrosive carbon-textile reinforcement cracks might be distributed so fine, that such an overlay can be executed jointless, unlike in previous repair methods. For a durable repair the bond behaviour between the retained concrete and the overlay as well as between the overlay-concrete and the textile reinforcement have to be considered. In this paper, the basic principles and feasibility of such a repair method are examined. On the one hand, the decisive influencing variables and parameters such as bond behaviour and cracking behaviour within the overlay are pointed out and discussed. On the other hand, the performed special lab tests will be presented. These tests include cyclic loadings on large-scale beams with integrated overlays of such types, evaluating the bond behaviour and the durability after a few millions of load cycles. Furthermore, the crack formation in the overlay is determined by means of tensile and flexural tensile strength tests.
Comparison between concrete stress diagrams according to the Brazilian standard ABNT NBR 6118: 2014
Authors: Oliveira Victor Hugo Dalosto de , Carvalho Rodolfo Alves , Borges Luana Ferreira , Martins Paulo Chaves de Rezende , Neves Rodolfo Rabelo , Siqueira João Paulo de Almeida , Oliveira Gabriel Yves da Silva , Anhaia Cintia Adriana Azevedo de Liz
Published: April 2022

This study aims to compare methods for the determination of concrete properties by means of the stress diagrams present in the Brazilian standard ABNT NBR 6118: 2014. The area under the stress diagram, the internal reactions, and the application point of the resulting reactions for the parabola-rectangle and rectangular block diagrams are present in order to compare them. Deductions and numerical examples were used, and different results were obtained for each formulation. This is due to non-consideration of the relationship between stress and strain in the simplified rectangular block. The rectangular block is applicable only for cases in which the concrete reaches the ultimate strain. These cases are those that concrete crushing determines the section failure in compression with steel yielding in tension (domain 3) or without steel yielding (domain 4).
Microstructural characterization of high-performance steel fiber reinforced geopolymer concrete
Authors: Ralli Zoi G. , Pantazopoulou Stavroula J. , Papangelakis Vladimiros G.
Published: April 2022

Due to growing environmental and economic concerns associated with conventional building materials, research interest gravitates towards the development of novel environmentally friendly materials as alternatives to conventional Portland cement concrete. Geopolymer concrete is a class of novel advanced and sustainable structural materials that hold promise for the future of infrastructure. Its synthesis comprises industrial by-products (fly ash and slag among others) in the role of binder and thus reduces the demand in Portland cement leading to a significant carbon footprint reduction. In the present study a High-Performance Fiber Reinforced Geopolymer Concrete (HPFRGC) is synthesized from first principles and is subsequently characterized, with particular emphasis on its microstructural and mineralogical properties. The study explores the linkage between the microstructure and mineralogy of the precursors, and the properties of the final product. Both fresh and hardened HPFRGC are studied. Experimental results illustrate the correlation between microstructure, mineralogy and final mechanical properties can be used as an indicator of suitability of industrial by-products for geopolymer precursors. The effect of these choices on stability and physical properties of the material is also explored in the study.
A revival in façades: Textile reinforced concrete panels are light, safe and aesthetically pleasing
Authors: Roik Matthias , Tietze Matthias , Kahnt Alexander
Published: April 2022

Textile reinforced concrete was developed in recent years into a construction technique that has its benefits and advantages in applications where conventional types of reinforcement have their limits. The current, minimum slab thickness for steel-reinforced concrete façade slabs is 7.0 cm; this is due to the minimum, required concrete cover to ensure adequate corrosion protection. Façade slab anchors for these slab thicknesses are building authority approved. As corrosion protection is not an issue for textile reinforced concrete, the minimum thickness for the concrete cover can be significantly reduced. The requirement for component thickness is now determined by the load-bearing capacity and by production-related boundary conditions. For practical building reasons, panel thicknesses of 3.0 cm have proven to be the best choice. Compared to steel-reinforced façade panels, this is a weight and thickness reduction of almost 60%. Thin concrete elements are of great interest in cases when the thickness or the weight of the panels is largely limited e.g. because of adjoining concrete elements in renovation or upgrade projects, retrofitting or improvements. Compared to other building materials, concrete has characteristic advantages in building physics and fire protection properties, irrespective of the thickness. Obviously, minimal thicknesses place extra demands on planning and construction. Especially effects on concrete, punching, splitting and concrete breakout must be examined in experiments. This is an overview of calculation and test methods. Results are provided to show the bearing behaviour of fixings in thin, textile reinforced concrete slabs. The design rules are explained and the results are illustrated.
Improvement mechanism of recycled concrete using C-S-H type accelerator and modifying recycled aggregate by carbonation technology
Authors: Shibuya Akari , Matsuda Nobuhiro , Iyoda Takeshi
Published: April 2022

In Japan, there is concern that concrete blocks due to demolition will increase with the renewal of concrete structures. Although it has been used for roadbed materials as recycling, in recent years, aggregates are removed from the concrete mass by crushing and grinding and used again as concrete aggregates. In concrete using recycled aggregates, it is necessary to take account of insufficient strength, drying shrinkage, freeze-thaw resistance. In previous study, the quality of recycled aggregates was improved by adsorbing carbon dioxide to recycled aggregates, and recycled concrete used the modified aggregates has been confirmed to increase strength and reduce drying shrinkage. In this study, we focused on the aggregate interface of concrete such as the interfacial transition zone for the purpose of clearing the quality improvement method of recycled concrete. We attempted to modify the aggregate interface using a C-S-H hardening accelerator using two recycled aggregates of different quality and concrete using ordinary aggregates. We will also compare which is more effective, concrete that tried to modify the aggregate interface and recycled concrete that uses carbonated modified recycled aggregate. We try include strength test, drying shrinkage test, and freeze-thaw test. We clarify the matters concerned about recycled concrete.
Using an analysis of concrete and cement epd: verification, selection, assessment, benchmarking and target setting
Authors: Schmitt Lucie , Jeong Jena , Potier Jean-Marc , Izoret Laurent , Mai-Nhu Jonathan , Decousser Nicolas , Pernin Thomas
Published: April 2022

Carbonation of concretes is a natural physico-chemical process that can be described as a reaction between the carbon dioxide contained in the air and the cement matrix. Carbonation concerns all concretes types in contact with the ambient air but also concretes in ground, from production stage to use and end-of-life stages. The amount of carbon dioxide bound varies according to the type of binder, the compacity of concrete and the environmental conditions during the use and the end-of-life stages. To consider the re-carbonation of concrete, works have been carried out within the framework of the European standardization group CEN/TC229/WG5 and in CEN/TC104. A methodology to consider the re-carbonation of concrete structures has been proposed in the NF EN 16757 standard on environmental product declarations for concrete and concrete elements. In addition, FD CEN/TR 17310 provides detailed recommendations regarding carbonation and absorption of carbon dioxide in concrete and give some precisions for application of NF EN 16757. This is an important topic towards a sustainable development in the current context of circular economy and CO2 uptake related to the French energy labelling (E+C-). In this paper, numerical and analytical carbonation models are used to estimate the CO2 binding ability of concrete structures. The obtained results are compared to the methodology proposed in Appendix BB of NF EN 16757 standard. They confirm that the methodology described in the NF EN 16757 standard leads to estimated degree of carbonation of the same order of magnitude. The advantage of using more advanced models lies in a better consideration of environmental parameters, the possibility to simulate the behaviour of crushed concrete, its reuse in new concrete as recycled aggregate and the possibility to simulate the carbonation of concretes in ground. This is an immediate perspective in the ongoing work in the French national project FastCarb on accelerated carbonation of recycled concrete aggregates.
Concrete admixtures - sustainable concrete
Authors: Schwoon Oliver
Published: April 2022

Durability of concrete, an important part of the sustainability theme, was, is, and will be one of the main topics for large infrastructure projects like the Gotthard base tunnel. For such important structures a service life of more than 80 years is expected. The prevailing underground conditions like water ingress, aggressive waters etc. will influence the choice of the concrete system and mix design. Therefore, a focus is on the potential damage mechanisms on the concrete like chloride ingress or sulfate attack. A well-designed concrete will be durable concrete which can withstand various external attacks and achieves or even extends the designed service life of the concrete structure. Based on the knowledge that the main damaging mechanisms for concrete are based on water penetration into the concrete, various measures can be taken to achieve concrete structures with significantly reduced permeability. These measure ranges from reduction of the water/binder-ratio, increasing the density of the concrete using silica fume, to the use of special admixtures in order to increase the durability of concrete. In an extensive research program, the influence of mix design components e.g. different admixture types, water/binder-ratio on hardened concrete properties like chloride resistance (chloride migration coefficient), sulfate resistance and water conductivity have been tested and analyzed.
Unique and innovative technology for sustainable and efficient structural concrete made of 100% recycled aggregate from CDW
Authors: Slánský Bohuslav , Zelinka Pavel , Čermák Jan
Published: April 2022

For supporting an environmental and social approach to the construction industry, the authors are bringing a new unique technology for maintaining the production of sustainable and efficient structural concrete made of 100% of recycled aggregate from construction demolition waste (CDW) as a replacement of natural aggregate. A wide range of laboratory testing of concrete with a grade up to C 30/37 using brick and concrete recycled aggregate as well as pilot projects will be presented with very successful results. This has been done by taking a different approach to the concrete mix design and production using new modern materials as well as new methods. Then full-scale production testing proved the new concept with only a minor adjustment in concrete plant technology. This new solution has very positive environmental impact and cost optimization shows its great potential for use as a structural concrete supporting a circular economy, saving natural sources, minimizing dumping and landfilling of CDW as well as reducing the CO2 footprint. This innovative technology makes the reuse of CDW possible in concrete with higher added value in the construction production chain (up-cycling) compared to conservative CDW downcycling. This unique concrete production together with proper CDW management brings with it a quite cost-effective contribution to the building industry and market.
Fracture behavior of multiple adhesive postinstalled anchors subjected to shear force
Authors: Tajima Yuji , Hoki Kazuaki
Published: April 2022

In this study, experiments were conducted on post-installed anchors subjected to shear force  in order to enhance applicability when post-installed anchors were used for seismic reinforcement. Furthermore, since there were a large number of post-installed anchors when they were actually used, an experiment was conducted in which aăshear force was simultaneously applied to one to four anchors. In this study, it was focused on number and pitch of anchors. Major findings of this study were summarized as follows: in case of 22.46 (N/mm2) for concrete compressive strength, shear strength of anchors was not double, triple, and quadruple as number of those increased to 2, 3, and 4, and that gradually decreased as number of those increased, the boundary condition between anchor shear rupture and pry-out failure was found that concrete compressive strength was 25.12 (N/mm2) or less and anchor pitch was 30 to 50 mm, and anchor was tensile strength over SD390.
Effect of using biomass fly ash on the concrete sustainability
Authors: Teixeira Elisabete Rodrigues , Camões Aires , Branco Fernando G.
Published: April 2022

Biomass fly ash has been studied has a partial cement material, since this material has a positive effect on concrete properties. Even though, some mixes with BFA presents a positive benefit, they need to be economically competitive and present a good environmental performance. So, the analyse and comparison of concrete that uses BFA as raw material substitution in terms of environmental impacts related to the production of conventional concrete. One of the best approaches to develop this type of study is to use the life cycle assessment (LCA) method. This method quantifies both the input flows, such as energy, water and materials, as well as the output flows, such as CO2 emission, solid wastes and liquid wastes. Based both on the abovementioned context and methodological approach, a quantification and comparison of potential environmental impacts resulting from the production of 1 m3 of concrete was made, using different types of binder and quantities of cement substitution.
Tension-free thyroidectomy — results of the initial 77 operations
Authors: Sleptsov I. V. , Chernikov R. A. , Sablin I. V. , Pushkaruk A. A. , Timofeeva N. I.
Published: April 2022

BACKGROUND: Surgeons from all over the world make considerable efforts to reduce thyroid intraoperative complications such as recurrent laryngeal nerves trauma and parathyroid vascular supply damage.

AIM: The aim of the study was improving thyroidectomy technique to reduce the rate of postoperative complications.

MATERIALS AND METHODS: Inclusion criteria were primary thyroid operation in cases of papillary or medullary cancer, follicular tumours (Bethesda IV) and Grave’s disease. Thyroid volume ranged from 12–70 ml. Tension-free technique of thyroidectomy (TFT) was suggested by the authors of this study. Key points of TFT are the following: the first step is the complete dissection of Berry ligament fibers and terminal branches of lower thyroid arteries and vein. There is only lateral traction while medial traction is not applied at all. Mobilization of the upper parathyroid gland is performed at the medial thyroid surface. Thyroid lobe is extracted out of its bed beginning with the lower pole only after complete dissection of Berry’s ligament, vessels and parathyroid glands. The last step of the operation is the dissection of the upper pole thyroid vessels. The mobilized lobe is easily withdrawn downwards, that leads to space increase between external branch of the superior laryngeal nerve and the upper pole of the lobe. Transient and continuous neuromonitoring as well as optical magnification and headlamps were used during operations. Vocal cords function was controlled before and after surgery (on the first day) by means of ultrasound or endoscopic laryngoscopy. Ionized calcium and parathyroid hormone levels were checked in cases of total thyroidectomy group on the day of surgery, on the 1st and 14th postoperative days.

RESULTS: 77 consecutive patients were included into the study (continuous sampling of patients). 33 hemithyroidectomies, 13 hemithyroidectomies with central ipsilateral neck dissection, 21 thyroidectomies, 8 thyroidectomies with central neck dissection, 2 thyroidectomies with central and lateral neck dissection were performed by the same surgeon. All the operations were performed by tension-free technique (TFT). There were no cases of loss of signal from the recurrent laryngeal nerves function during all the operations. One case of postoperative transient hypoparathyroidism finished with normalization of parathyroid hormone and calcium levels in 2 weeks after the operation.

CONCLUSION: initial experience in TFT allows to recommend this procedure for further practicing and examination.
Features of preparation and surgical aspects of treatment of patients with ACTH-producing neuroendocrine lung tumors
Authors: Pikunov M. Yu. , Pechetov A. A. , Golounina O. O. , Buryakina S. A. , Rozhinskaya L. Ya. , Belaya Zh. E.
Published: April 2022

BACKGROUND: The Department of Thoracic Surgery of the National Medical Research Center of Surgery named after A. V. Vishnevsky has been dealing with the problem of surgical treatment of patients with neuroendocrine lung tumors for more than 20 years. This article presents the experience of treating patients with ectopic ACTH syndrome over the past 15 years.

AIM: To study the features of preparation, surgical aspects of treatment and delayed results in patients with ACTH-producing tumors of bronchopulmonary localization.

MATERIALS AND METHODS: The study included 55 patients who underwent surgical treatment of ACTH-producing neuroendocrine tumor of bronchopulmonary localization in the period from 2005 to 2020. In order to systematize the approach to surgical treatment and the choice of the type of operation, a point analysis of the patient’s severity has been developed. Demographic information about patients, anamnesis data, results of hormonal and instrumental studies at pre- and postoperative stages and long-term treatment results were analyzed. The control period of observation of patients after surgery ranged from 6 months to 5 years.

RESULTS: The age of the patients ranged from 18 to 72 years (36±15). According to the MSCT results of the chest, neoplasms in the lungs ranging in size from 5 to 25 mm were detected. Patients who scored from 18 to 23 points had lung resection due to the severity of the condition. With a total score from 14 to 18, segmentectomy with lymph node dissection was performed. When the total score was less than 14, a lobectomy with lymph node dissection was performed. During the planned histological examination, lung neuroendocrine tumor of various differentiation degree was confirmed in all patients. The results of treatment were followed in the period from 6 to 60 months, with a median of 19 months [10;24]. Regression of clinical manifestations of hypercortisolism after 1 year of dynamic follow-up period was detected in 83% of patients. After 60 months of follow-up 10 patients (71.4%) had a persistent clinical effect after surgical treatment with complete regression of hypercortisolism symptoms.

CONCLUSION: The analysis of the results of surgical treatment, according to the proposed methodological aspects, with dynamic control after 6, 12 and 36 months showed the effectiveness of such surgical intervention with results comparable to the world indicators of leading clinics.
Programa de acompanhamento de egressos de graduação em uma universidade pública: uma avaliação por ex-alunos
Authors: Santos Moyza Teixeira de Oliveira dos , Vilarinho Lúcia Regina Goulart
Published: April 2022

O estudo objetivou avaliar o Programa Joia Rara (PROJOIA) que promove o acompanhamento de egressos da graduação da Universidade Federal do Estado do Rio de Janeiro. Com base na abordagem avaliativa centrada na administração, foram analisados os dados gerados pelo questionário do programa respondido por 1199 egressos entre os anos de 2015 e 2020. Os resultados permitem concluir que o PROJOIA dispõe de mecanismo que possibilita avaliar a opinião dos egressos a respeito da formação recebida, mas necessita promover maior integração dos cursos com as necessidades do mundo do trabalho.
Agenda neoliberal, juventude e trabalho: uma análise discursiva de coleções didáticas do Novo Ensino Médio
Authors: Silva Francisco Vieira da , Morais Edvânia Batista de
Published: April 2022

O artigo analisa coleções didáticas do Novo Ensino Médio aprovadas pelo Programa Nacional do Livro e do Material Didático (PNLD), edição de 2021, levando em consideração os impactos reformistas de matriz neoliberal a incidirem sobre o trabalho e a educação para os jovens no Brasil. O objetivo consiste em investigar como discursos sobre o trabalho em três coleções didáticas de Projeto de Vida articulam-se com a racionalidade neoliberal. Trata-se de uma pesquisa descritivo-interpretativa, de natureza documental e qualitativa. Foi possível observar que a conexão entre o trabalho e o neoliberalismo ocorre por meio de regularidades discursivas relativas às instabilidades do mundo do trabalho e a necessidade de engendrar condutas juvenis flexíveis, proativas e autônomas.
Estado neoliberal e retrocessos democráticos nas políticas públicas de educação
Authors: Silva Maria Vieira da
Published: April 2022

As teorizações do sociólogo francês Christian Laval têm se constituído em importantes referenciais para pesquisadores da área de humanidades. Suas análises enfocam de forma densa dimensões da nova racionalidade política, a qual transversaliza governos, economia, sociedade e Estado e incidem sobre a produção de subjetividades e regulação das existências. Na presente entrevista, Laval nos possibilita compreender o percurso de suas formulações sobre o denominado “Novo neoliberalismo” sustentado por políticas econômicas de austeridade, pela mercantilização das relações sociais e da ditadura dos mercados financeiros como também o papel da escola no processo de produção de subjetividades para a racionalidade política da lógica neoliberal contemporânea.
Novas diretrizes curriculares nacionais: necessidades individuais, sociais ou mercadológicas?
Authors: Santos Ana Palmira Soares dos , Giordani Camila Cunha Oliveira , Lima Jacqueline Oliveira
Published: April 2022

O presente trabalho aborda a configuração das novas Diretrizes Curriculares Nacionais para a Educação Profissional - publicadas por meio da Resolução nº 1, de 5 de janeiro de 2021, do Conselho Pleno do Conselho Nacional de Educação - procurando identificar os compromissos firmados, as rupturas e as continuidades em relação às políticas para a Educação Profissional implementadas especialmente a partir da publicação da Constituição Federal. De acordo com os idealizadores do documento, a Resolução unifica, atualiza e supera a segmentação entre todos os níveis de ensino presentes nos documentos anteriores, a saber, o de1999, sobre a Educação Profissional de nível técnico, o de 2002, sobre a Educação Tecnológica, e o de 2012, sobre a Educação Profissional de nível médio.
A Teoria do Capital Humano e as políticas de correção de fluxo: um recorte educacional da Amazônia Rondoniense
Authors: Matias Juliana Cândido , Barros Josemir Almeida
Published: April 2022

A pesquisa objetivou compreender a relação entre políticas de correção de fluxo e a Teoria do Capital Humano a partir da distorção idade-série na região norte do Brasil. Entre as indagações destaca-se: quais os contextos da distorção idade-série na Amazônia rondoniense? Em termos metodológico, utilizou-se pesquisa bibliográfica e documentos oficiais e estatísticos do Instituto Nacional de Estudos e Pesquisas Educacionais Anísio (Inep), Sistema de Avaliação da Educação Básica (Saeb) e Índice de Desenvolvimento da Educação Básica (Ideb). Identificou-se potencial influência entre a Teoria do Capital Humano de Theodore Schultz (1966) e as políticas educacionais de correção de fluxo implementadas no Brasil desde a década de 1970 na Amazônia rondoniense.
Systematic Literature Review of Competitive Advantage and Marketing Capability of Small Medium Enterprises (SMEs)
Authors: Nurlatifah Hanny , Saefuddin Asep , Marimin Marimin , Suwarsinah Heny
Published: April 2022

The discussion about the formation of competitive advantage in work organizations such as SMEs is still not widely discussed. The current literature still discusses marketing activities in general, not specifically for SMEs. This article aims to find out the factors that influence SMEs' competitive advantage and marketing capabilities. The literature review method systematically uses three stages. First planning for selecting source articles, second implementing and reporting stage. The PRISMA Literature Review Model selects articles and data visualization using VOS Viewer software. The findings of this article are the related potential relationships between marketing capabilities as forming competitive advantages for small and medium enterprises. Eleven topics are frequently discussed in a collection of journals, and the dominant words are sustainable marketing orientation, marketing, and Company Performance. The three groups can be grouped into personality development, business management, and abilities. Differences in the types of business groups and business sizes as differentiators of business performance results are not widely seen in article searches. These findings suggest further research to examine business groups' role and size in determining SMEs' competitive advantage and marketing capabilities.
Diffusion of molecules through nanopores under confinement: Time-scale bridging and crowding effects via Markov state model
Authors: Bodrenko Igor V. , Milenkovic Stefan , Ceccarelli Matteo
Published: April 2022

Passive transport of molecules through nanopores is characterized by the interaction of molecules with pore internal walls and by a general crowding effect due to the constricted size of the nanopore itself, which limits the presence of molecules in its interior. The molecule–pore interaction is treated within the diffusion approximation by introducing the potential of mean force and the local diffusion coefficient for a correct statistical description. The crowding effect can be handled within the Markov state model approximation. By combining the two methods, one can deal with complex free energy surfaces taking into account crowding effects. We recapitulate the equations bridging the two models to calculate passive currents assuming a limited occupancy of the nanopore in a wide range of molecular concentrations. Several simple models are analyzed to clarify the consequences of the model. Eventually, a biologically relevant case of transport of an antibiotic molecule through a bacterial porin is used to draw conclusions (i) on the effects of crowding on transport of small molecules through biological channels, and (ii) to demonstrate its importance for modelling of cellular transport.
Experimental investigation of composite steel–concrete beams using symmetrical and asymmetrical castellated beams
Authors: Al-Thabhawee Hayder Wafi
Published: April 2022

This study aims to investigate the behavior of concrete slabs acting compositely with symmetrical and asymmetrical castellated beams. Stud connectors are used to connect the concrete slab and steel section. The use of castellated steel beams to build up composite steel-concrete beams is now common practice in building construction. Five simply supported composite beams were examined under two-point loading. Two specimens built up from standard steel beams were used as control specimens and three specimens were built up from castellated steel beams. One of these specimens was built up using a castellated steel beam with an asymmetrical cross-section fabricated from two different standard sections (IPE120/HEA120). The concrete slab of all composite specimens had the same dimensions and properties. The experimental results showed that strength and rigidity were considerably greater for composite castellated steel beams compared to composite beams built up from the parent sections. The ultimate load capacity of a composite castellated beam fabricated from an IPE120 section was 46% greater than that of a composite beam built up using the parent beam, and the ultimate load capacity of a composite castellated beam fabricated from a wide-flanged HEA120 section resulted in an increase of 21% over the parent beam control specimen. The ultimate load capacity of the composite specimen built up using the asymmetrical castellated beam (IPE120/HEA120) achieved increases of 69% and 12%, respectively, compared to the control specimens built up from standard sections.
Experimental investigation and thermodynamic assessment of the Al–Ca–Y ternary system
Authors: Zhang Ligang , Song Qian , Jiang Yurong , Zhao Fenyan , Liu Libin
Published: April 2022

The experimental investigation and thermodynamic assessment of the Al–Ca–Y ternary system were carried out in this work. The isothermal section of the Al–Ca–Y ternary system at 673 K and 873 K was determined by using equilibrated alloys, combined with scanning electron microscopy, electron probe micro-analysis and powder X-ray diffractometry. Phase transition temperatures were measured by differential scanning calorimetry analysis. A certain range of solubility was detected between Al2Ca and Al2Y in this work, the maximum solid solubility of Y in Al2Ca was 11.9 at.% and that of Ca in Al2Y was 12.6 at.%. According to the thermodynamic data of binary systems in the literature and the ternary experimental data from this work and the literature, the Al–Ca–Y ternary system was optimized and a set of self-consistent thermodynamic parameters was obtained. Calculated phase equilibria were consistent with the experimental results.
Graphene-based nanocomposite using new modeling molecular dynamic simulations for proposed neutralizing mechanism and real-time sensing of COVID-19
Authors: Fatema Kamrun Nahar , Sagadevan Suresh , Cho Ju Yong , Jang Won Kweon , Oh Won-Chun
Published: April 2022

A new virus, the coronavirus (COVID-19), is causing serious respiratory infections in humans. Rapid, specific, and sensitive diagnostic techniques for early-stage detection of SARS-CoV-2 viral protein are developing as a necessary response for effective smart diagnostics, treatment optimization, and exploration of therapeutics with better effectiveness in the fight against the COVID-19 pandemic. Keeping the considerations mentioned above, we propose a new modeling graphene nanocomposite-based biosensing device for detecting COVID-19 at the site of the epidemic as the best way to manage the pandemic. It is important to address the problems of COVID-19 management. With the challenges and aspects of COVID-19 management in mind, we present in this review a collective approach involving electrochemical COVID-19 biosensing required for early-stage COVID-19 diagnosis and the direct interaction with viral surface glycoproteins and metal nanoparticles that can enter cells and neutralize viruses by interacting directly with the viral genome (ribonucleic acid), which identifies the COVID-19 spike protein and antiviral procedure including virus inactivation, host cell receptor inactivation, electrostatic entrapment, and physicochemical destruction of viral species by nucleotide ring opening. The interactions between the graphene composite and virus may be boosted by functionalization of the carbon surface and decoration of metallic components that enhance these interactions. Our proposed new modeling molecular dynamic simulation-based neutralizing mechanism and real-time detection of COVID-19 on graphene nanocomposite-based biosensors are suitable for point-of-care diagnostic applications, and this sensing platform can be modified for the early diagnosis of severe viral infections using real samples. For the potential application, the suggested one is the chemical reaction and bond breaking between the metallic component and molecule of COVID19 with computer simulation data.
Weight trajectory during the COVID-19 pandemic: A cross-sectional study in Malaysia
Authors: Tan Seok Tyug , Tan Seok Shin , Tan Chin Xuan
Published: April 2022

This study examines the weight trajectory of Malaysian adults and its associated factors during the COVID-19 pandemic. Sociodemographic information and anthropometric measurements, including body height (cm) and body weights (kg) before and during the pandemic, were self-reported by the respondents. The current study showed that 47.8% (using absolute weight change status) and 25.5% (using relative weight change status) of the adults gained weight during the COVID-19 pandemic. Adults who were previously underweight or had a normal BMI experienced significantly higher body weight (under-weight: t= -6.176, p< 0.001 and normal: t= -6.193, p< 0.001) and BMI (underweight: t= -6.127, p< 0.001 and normal: t= -5.982, p< 0.001) during the pandemic. No significant associations were observed between socio-demographic characteristics and the weight status of the respondents, except for ethnicity (χ2= 12.858, p= 0.045). The stay-at-home orders appeared to drive up the prevalence of over-weight/obesity, BMI, and absolute and relative weight gain in Malaysian adults. The increase was mainly associated with higher body weight and BMI among those previously underweight or had a normal BMI. Gender, age, marital status, and educational level were not associated with weight trajectory during the COVID-19 pandemic. The findings of this study may be useful in formulating weight management strategies in the post-pandemic era.