bluuebunny/crossref_metadata_2025 huggingface dataset:
Differentiation of human adult-derived stem cells towards a neural lineage involves a dedifferentiation event prior to differentiation to neural phenotypes
Authors: Bueno Carlos , Martínez-Morga Marta , García-Bernal David , Moraleda José M. , Martínez Salvador
Published: June 2021

Although it has been reported that mesenchymal stem cells isolated from adult tissues can be induced to overcome their mesenchymal fate and transdifferentiate into neural cells, the findings and their interpretation have been challenged. The main argument against this process is that the cells rapidly adopt neuron-like morphologies through retraction of the cytoplasm rather than active neurite extension. In this study, we examined the sequence of biological events during neural differentiation of human periodontal ligament-derived stem cells (hPDLSCs), human bone marrow-derived stem cells (hBMSCs) and human dental pulp-derived stem cells (hDPSCs) by time-lapse microscopy. We have demonstrated that hPDLSCs, hBMSCs and hDPSCs can directly differentiate into neuron-like cells without passing through a mitotic stage and that they shrink dramatically and change their morphology to that of neuron-like cells through active neurite extension. Furthermore, we observed micronuclei movement and transient cell nuclei lobulation concurrent to in vitro neurogenesis from hBMSCs and hDPSCs. Our results demonstrate that the differentiation of hPDLSCs, hBMSCs and hDPSCs towards a neural lineage occurs through a dedifferentiation step followed by differentiation to neural phenotypes, and therefore we definitively confirm that the rapid acquisition of the neural phenotype is via a differentiation trait.
Depth of field measures in pseudophakic eyes implanted with different type of presbyopia-correcting IOLS
Authors: Palomino-Bautista Carlos , Sánchez-Jean Rubén , Carmona-Gonzalez David , Piñero David P. , Molina-Martín Ainhoa
Published: June 2021

To evaluate depth of field (DOF) provided by different presbyopia-correcting intraocular lens (IOL) designs, comparing the results obtained using different criteria for defining the defocus tolerance. A total of 150 eyes undergoing cataract surgery were enrolled and divided into 6 groups depending on the IOL implanted: AT.LISA Tri (Carl Zeiss Meditec), FineVision (PhysIOL), PanOptix (Alcon Laboratories), Tecnis Symfony (Johnson & Johnson Vision), Miniwell (SIFI MedTech) and Tecnis Synergy (Johnson & Johnson Vision). Subjective DOF was obtained from defocus curves with absolute and relative criteria of tolerance of 0.1 logMAR. Aberrometry was also measured and the visual strehl optical transference function (VSOTF) with percentage of degradation of 90%, 80% and 60% was used to quantify objectively the DOF. Tecnis Symfony, Tecnis Synergy and Panoptix IOL groups showed better subjective and objective DOF compared to the rest of IOL groups, being these differences statistically significant differences (p < 0.001). Comparison between subjective and objective DOF showed that subjective measures were higher for all IOLs, being also these differences statistically significant for all groups (p < 0.001). A moderate significant correlation was found between absolute subjective criteria and VSOTF60% (r = 0.73, p < 0.05). Objective and subjective measures of DOF are not comparable due to differences in methodologies and criterions to define the level of degradation tolerance. Nevertheless, both objective and subjective measures showed a trend to a greater DOF for Tecnis Symfony and Tecnis Synergy IOLs compared to most of trifocal diffractive designs, with the exception of PanOptix.
The impact of different first-line EGFR-TKIs on the clinical outcome of sequential osimertinib treatment in advanced NSCLC with secondary T790M
Authors: Huang Yen-Hsiang , Tseng Jeng-Sen , Hsu Kuo-Hsuan , Chen Kun-Chieh , Su Kang-Yi , Yu Sung-Liang , Chen Jeremy J. W. , Yang Tsung-Ying , Chang Gee-Chen
Published: June 2021

The impact of different first-line epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI)s to the clinical efficacy of osimertinib in EGFR-mutant non-small-cell lung cancer (NSCLC) patients with acquired T790M was still unclear. We enrolled 733 advanced EGFR-mutant NSCLC patients with gefitinib, erlotinib or afatinib as first-line EGFR-TKIs treatment for analysis. 373 patients received re-biopsies after progressive disease to first-line EGFR-TKIs treatment, and the total positive rate of T790M was 51.7%. 151 patients who harbored T790M received osimertinib as subsequent treatment. Among them, the median progression-free survival (PFS) of first-line EGFR-TKI (PFS1) was 14.0 months, and the median PFS of osimertinib (PFS2) was 10.1 months. The median PFS1 + PFS2 was 27.5 months, and the median overall survival from first-line EGFR-TKI was 61.3 months. Concerning different first-line EGFR-TKIs, the median PFS2 was 10.9 months in the gefitinib group, 10.0 months in the erlotinib group, and 6.7 months in the afatinib group (p = 0.534). The median PFS1 + PFS2 was 27.7 months, 26.8 months and 24.0 months in the gefitinib, erlotinib, and afatinib group, respectively (p = 0.575). In conclusion, both first-generation and second-generation EGFR-TKIs sequential osimertinib treatment provided good clinical efficacy in advanced EGFR-mutant NSCLC patients with acquired T790M mutation.
Bypassing use-dependent plasticity in the primary motor cortex to preserve adaptive behavior
Authors: Bosc M. , Bucchioni G. , Ribot B. , Michelet T.
Published: June 2021

Behavioral adaptation, a central feature of voluntary movement, is known to rely on top-down cognitive control. For example, the conflict-adaptation effect on tasks such as the Stroop task leads to better performance (e.g. shorter reaction time) for incongruent trials following an already incongruent one. The role of higher-order cortices in such between-trial adjustments is well documented, however, a specific involvement of the primary motor cortex (M1) has seldom been questioned. Here we studied changes in corticospinal excitability associated with the conflict-adaptation process. For this, we used single-pulse transcranial-magnetic stimulation (TMS) applied between two consecutive trials in an interference flanker task, while measuring motor-evoked potentials (MEPs) after agonistic and antagonistic voluntary movements. In agonist movement, MEP amplitude was modulated by recent movement history with an increase favoring movement repetition, but no significant change in MEP size was observed whether a previous trial was incongruent or congruent. Critically, for an antagonist movement, the relative size of MEPs following incongruent trials correlated positively with the strength of behavioral adaptation measured as the degree of RT shortening across subjects. This post-conflict increase in corticospinal excitability related to antagonist muscle recruitment could compensate for a potential deleterious bias due to recent movement history that favors the last executed action. Namely, it prepares the motor system to rapidly adapt to a changing and unpredictable context by equalizing the preparation for all possible motor responses.
Author Correction: The impact of environmental variables on the spread of COVID-19 in the Republic of Korea
Authors: Lim Yong Kwan , Kweon Oh Joo , Kim Hye Ryoun , Kim Tae‑Hyoung , Lee Mi‑Kyung
Published: June 2021

An amendment to this paper has been published and can be accessed via a link at the top of the paper.
Preventive and therapeutic effects of Lactobacillus rhamnosus SHA113 and its culture supernatant on alcoholic gastric ulcers
Authors: Yang Rongrong , Li Junjun , Xu Xiaoguang , Xu Keyi , Shi Junling
Published: June 2021

L. rhamnosus SHA113 and its culture supernatant can prevent and therapeutically treat alcoholic gastric ulcers via enhancing the gastric mucosal barrier function.
Clinically oriented Alzheimer's biosensors: expanding the horizons towards point-of-care diagnostics and beyond
Authors: Murti Bayu Tri , Putri Athika Darumas , Huang Yi-June , Wei Shih-Min , Peng Chih-Wei , Yang Po-Kang
Published: June 2021

Advancements of clinically driven biosensors in current Alzheimer's diagnosis are highlighted in both in vitro and in vivo applications.
Fabrication and application of a MIL-68(In)–NH2 incorporated high internal phase emulsion polymeric monolith as a solid phase extraction adsorbent in triazine herbicide residue analysis
Authors: Luo Jinhua , Jiang Liping , Ruan Guihua , Li Chengyong , Du Fuyou
Published: June 2021

MIL-68(In)–NH2 incorporated high internal phase emulsion polymeric monoliths were fabricated and applied to extract and determine triazine herbicide residues in environmental water samples.
Radiation-initiated high strength chitosan/lithium sulfonate double network hydrogel/aerogel with porosity and stability for efficient CO2 capture
Authors: Liu Zhiyan , Ma Rui , Du Wenjie , Yang Gang , Chen Tao
Published: June 2021

Chitosan hydrogel is regenerated from alkali/urea aqueous solution and the lithium sulfonate second network is introduced by electron beam radiation-initiated in situ free radical polymerization. The freeze-dried aerogel has CO2 capture capacity.
Chain ordering of phospholipids in membranes containing cholesterol: what matters?
Authors: Keller Fabian , Heuer Andreas
Published: June 2021

We identify energy contributions that drive PL chain ordering of DPPC and DLiPC lipids in cholesterol mixtures and show that cholesterol not only contributes via direct interaction.
A diffusion encouraged core–shell heterostructured Co3Sn2@SnO2 anode towards emerging dual ion batteries with high energy density
Authors: Salunkhe Tejaswi Tanaji , Kadam Abhijit Nanaso , Kidanu Weldejewergis Gebrewahid , Lee Sang-Wha , Nguyen Tuan Loi , Kim Il Tae
Published: June 2021

A novel core–shell heterostructured Co3Sn2@SnO2 anode is explored for lithium dual ion batteries (LDIBs). The optimized Co3Sn2@SnO2 anode and expanded graphite cathode in an LDIB delivered notable energy density (334.5 W h kg−1).
Reduced interfacial tension on ultrathin NiCr-LDH nanosheet arrays for efficient electrocatalytic water oxidation
Authors: Zhang Xiuxiu , Sun Xuan , Li Yuanli , Hu Fengchun , Xu Yanzhi , Tian Jie , Zhang Hui , Liu Qinghua , Su Hui , Wei Shiqiang
Published: June 2021

Ultrathin NiCr-LDH nanosheet arrays were prepared by hydrothermal method. It has been revealed that reduced solid–liquid interfacial tension and exposed NiO6−x active centers enable fast formation of *OOH intermediates for efficient water oxidation.
Structural evolution of imine-linked covalent organic frameworks and their NH3 sensing performance
Authors: Niu Fang , Shao Zhen-Wu , Zhu Jia-Lin , Tao Li-Ming , Ding Yong
Published: June 2021

Imine-linked COFs have been successfully constructed and showed NH3 sensing ability at room temperature. The imine-linked COFs with a disordered structure had better NH3 sensing ability than those with a crystalline structure.
Effects of Bilateral Automatic Gain Control Synchronization in Cochlear Implants With and Without Head Movements: Sound Source Localization in the Frontal Hemifield
Authors: Pastore M. Torben , Pulling Kathryn R. , Chen Chen , Yost William A. , Dorman Michael F.
Published: June 2021

Purpose

For bilaterally implanted patients, the automatic gain control (AGC) in both left and right cochlear implant (CI) processors is usually neither linked nor synchronized. At high AGC compression ratios, this lack of coordination between the two processors can distort interaural level differences, the only useful interaural difference cue available to CI patients. This study assessed the improvement, if any, in the utility of interaural level differences for sound source localization in the frontal hemifield when AGCs were synchronized versus independent and when listeners were stationary versus allowed to move their heads.

Method

Sound source identification of broadband noise stimuli was tested for seven bilateral CI patients using 13 loudspeakers in the frontal hemifield, under conditions where AGCs were linked and unlinked. For half the conditions, patients remained stationary; in the other half, they were encouraged to rotate or reorient their heads within a range of approximately ± 30° during sound presentation.

Results

In general, those listeners who already localized reasonably well with independent AGCs gained the least from AGC synchronization, perhaps because there was less room for improvement. Those listeners who performed worst with independent AGCs gained the most from synchronization. All listeners performed as well or better with synchronization than without; however, intersubject variability was high. Head movements had little impact on the effectiveness of synchronization of AGCs.

Conclusion

Synchronization of AGCs offers one promising strategy for improving localization performance in the frontal hemifield for bilaterally implanted CI patients.

Supplemental Material

https://doi.org/10.23641/asha.14681412
Effects of Visual Speech Envelope on Audiovisual Speech Perception in Multitalker Listening Environments
Authors: Yuan Yi , Meyers Kelli , Borges Kayla , Lleo Yasneli , Fiorentino Katarina A. , Oh Yonghee
Published: June 2021

Purpose

This study investigated the effects of visually presented speech envelope information with various modulation rates and depths on audiovisual speech perception in noise.

Method

Forty adults (21.25 ± 1.45 years) participated in audiovisual sentence recognition measurements in noise. Target speech sentences were auditorily presented in multitalker babble noises at a −3 dB SNR. Acoustic amplitude envelopes of target signals were extracted through low-pass filters with different cutoff frequencies (4, 10, and 30 Hz) and a fixed modulation depth at 100% (Experiment 1) or extracted with various modulation depths (0%, 25%, 50%, 75%, and 100%) and a fixed 10-Hz modulation rate (Experiment 2). The extracted target envelopes were synchronized with the amplitude of a spherical-shaped ball and presented as visual stimuli. Subjects were instructed to attend to both auditory and visual stimuli of the target sentences and type down their answers. The sentence recognition accuracy was compared between audio-only and audiovisual conditions.

Results

In Experiment 1, a significant improvement in speech intelligibility was observed when the visual analog (a sphere) synced with the acoustic amplitude envelope modulated at a 10-Hz modulation rate compared to the audio-only condition. In Experiment 2, the visual analog with 75% modulation depth resulted in better audiovisual speech perception in noise compared to the other modulation depth conditions.

Conclusion

An abstract visual analog of acoustic amplitude envelopes can be efficiently delivered by the visual system and integrated online with auditory signals to enhance speech perception in noise, independent of particular articulation movements.
Revision Peripheral Nerve Surgery of the Upper Extremity
Authors: Dibbs Rami P. , Ali Kausar , Sarrami Shayan M. , Koshy John C.
Published: June 2021

Peripheral nerve injuries of the upper extremity can result from a wide array of etiologies, with the two most common being compression neuropathy and traumatic injuries. These types of injuries are common and can be psychologically, functionally, and financially devastating to the patient. A detailed preoperative evaluation is imperative for appropriate management. Traumatic injuries can typically be treated with local burial techniques, targeted muscle reinnervation, and regenerative peripheral nerve interfaces. Median nerve compression is frequently managed with complete release of the antebrachial fascia/transverse carpal ligament and/or use of flap coverage such as the hypothenar fat pad flap and local muscle flaps. Ulnar nerve compression is commonly managed via submuscular transposition, subcutaneous transposition, neurolysis, and nerve wrapping. In this review, we discuss the preoperative evaluation, surgical techniques, and advantages and disadvantages of each treatment modality for patients with compressive and traumatic upper extremity nerve injuries.
Magnetic transitions and structural characteristics of Mn-doped α-Fe2O3/silica nanocomposites
Authors: Song Hyon-Min , Atanasov Ivo , Zink Jeffrey I.
Published: June 2021

Hematite (α-Fe2O3) has become popular these days for their photocatalytic activities of water splitting. Metal-doped hematite materials are interesting as well for the bandgap engineering and for resolving fast charge–hole recombination. In this study, magnetism and ionic behaviors of rare manganese-doped α-Fe2O3/silica nanocomposites are investigated. These nanocomposites are prepared by the impregnation method with a mixture of metal halides, followed by rapid heating (30 °C/min) under air condition. When the molar ratio between FeCl3·6H2O and MnCl2·4H2O is 2.97, wasp-waisted hysteresis and ferromagnetism with the Curie temperatures of 56.1 and 58.0 K are observed for the nanocomposites annealed at 600 °C for the duration of 3 and 7 h, respectively, while dominant spin glass states are observed for the nanocomposites annealed at 500 °C. In x-ray diffraction patterns, mixed phases of α-Fe2O3 are identified, whereas crystalline metallic Mn or Mn oxides are hardly found. Electron energy-loss spectroscopy study indicates that Mn2+ is severely oxidized, and with this oxidation of Mn2+, Si becomes more metallic. When the molar ratio between Fe and Mn halides is 7.32, magnetism is affected by a small amount of γ-Fe2O3, and spin glass states and the competition between ferromagnetism and antiferromagnetism are observed in the long temperature range.
Motion estimation and correction in SPECT, PET and CT
Authors: Kyme Andre Z , Fulton Roger R
Published: June 2021

Patient motion impacts single photon emission computed tomography (SPECT), positron emission tomography (PET) and x-ray computed tomography (CT) by giving rise to projection data inconsistencies that can manifest as reconstruction artifacts, thereby degrading image quality and compromising accurate image interpretation and quantification. Methods to estimate and correct for patient motion in SPECT, PET and CT have attracted considerable research effort over several decades. The aims of this effort have been two-fold: to estimate relevant motion fields characterizing the various forms of voluntary and involuntary motion; and to apply these motion fields within a modified reconstruction framework to obtain motion-corrected images. The aims of this review are to outline the motion problem in medical imaging and to critically review published methods for estimating and correcting for the relevant motion fields in clinical and preclinical SPECT, PET and CT. Despite many similarities in how motion is handled between these modalities, utility and applications vary based on differences in temporal and spatial resolution. Technical feasibility has been demonstrated in each modality for both rigid and non-rigid motion but clinical feasibility remains an important target. There is considerable scope for further developments in motion estimation and correction, and particularly in data-driven methods that will aid clinical utility. State-of-the-art deep learning methods may have a unique role to play in this context.
Acoustic wireless communication based on parameter modulation and complex Lorenz chaotic systems with complex parameters and parametric attractors*
Authors: Zhang Fang-Fang , Gao Rui , Liu Jian
Published: June 2021

As the competition for marine resources is increasingly fierce, the security of underwater acoustic communication has attracted a great deal of attention. The information and location of the communicating platform can be leaked during the traditional underwater acoustic communication technology. According to the unique advantages of chaos communication, we put forward a novel communication scheme using complex parameter modulation and the complex Lorenz system. Firstly, we design a feedback controller and parameter update laws in a complex-variable form with rigorous mathematical proofs (while many previous references on the real-variable form were only special cases in which the imaginary part was zero), which can be realized in practical engineering; then we design a new communication scheme employing parameter modulation. The main parameter spaces of the complex Lorenz system are discussed, then they are adopted in our communication scheme. We also find that there exist parametric attractors in the complex Lorenz system. We make numerical simulations in two channels for digital signals and the simulations verify our conclusions.
Soliton molecules and asymmetric solitons of the extended Lax equation via velocity resonance
Authors: Ma Hongcai , Wang Yuxin , Deng Aiping
Published: June 2021

We investigate the techniques for velocity resonance and apply them to construct soliton molecules using two solitons of the extended Lax equation. What is more, each soliton molecule can be transformed into an asymmetric soliton by changing the parameter ϕ. In addition, the collision between soliton molecules (or asymmetric soliton) and several soliton solutions is observed. Finally, some related pictures are presented.
Spin orbit torques in Pt-based heterostructures with van der Waals interface*
Authors: Chen Qian , Lv Weiming , Li Shangkun , Lv Wenxing , Cai Jialin , Zhu Yonghui , Wang Jiachen , Li Rongxin , Zhang Baoshun , Zeng Zhongming
Published: June 2021

Spin orbit torques (SOTs) in ferromagnet/heavy-metal heterostructures have provided great opportunities for efficient manipulation of spintronic devices. However, deterministically field-free switching of perpendicular magnetization with SOTs is forbidden because of the global two-fold rotational symmetry in conventional heavy-metal such as Pt. Here, we engineer the interface of Pt/Ni heterostructures by inserting a monolayer MoTe2 with low crystal symmetry. It is demonstrated that the spin orbit efficiency, as well as the out-of-plane magnetic anisotropy and the Gilbert damping of Ni are enhanced, due to the effect of orbital hybridization and the increased spin scatting at the interface induced by MoTe2. Particularly, an out-of-plane damping-like torque is observed when the current is applied perpendicular to the mirror plane of the MoTe2 crystal, which is attributed to the interfacial inversion symmetry breaking of the system. Our work provides an effective route for engineering the SOT in Pt-based heterostructures, and offers potential opportunities for van der Waals interfaces in spintronic devices.
Analysis of the microclimate of the halls of worship
Authors: Eremkin A I , Ponomareva I K
Published: June 2021

Carrying out rituals in the church hall of the cathedral is accompanied by a significant release of various hazards from parishioners and staff (heat, water vapor, carbon dioxide), when burning candles, from the use of censers and lamps (heat, carbon dioxide, fumes, soot, soot, water vapor), from consecration and solar radiation through external enclosures (heat). In the article, a local exhaust ventilation system with the use of umbrellas installed above the candlestick tabletop is proposed for trapping and removing harmful emissions from burning candles in a worship hall. To calculate air changes, it is important to have data on the amount of harmful substances emitted in the church hall of the cathedral. It is known that in the central part of the cathedral during the warm period of the year in the hall of worship at the permissible internal air temperature from 12 to 16 ° C and the optimum temperature from 14 to 16 ° C, one person emits an average of 50 g / h of water vapor. In the cold period of the year, when the permissible internal air temperature in the worship hall is from 12 to 16 ° C and the optimal temperature is 14 to 16 ° C, each parishioner emits on average up to 40 g / h of water vapor. Heat release from one person in full heat reaches 80 W in the warm season, and up to 100 W in the cold.
Inspection of sugar factory brick wall*
Authors: Serykh I R , Chernysheva E V , Degtyar A N
Published: June 2021

Nowadays a huge number of industrial buildings constructed in the last century need restoration. Structures with brick walls are in the list. The reason for this is the appearance of cracks, breaks, spalls, cavities, holloes and other discontinuities of brickwork; wall deformations; stratification of brickwork rows; humidification of walling, weathering and leaching of mortar; loss of individual bricks; damage to protective and finishing layers; efflorescence on the surface of brickwork and many other things.

The causes of such defects can be the following: unsatisfactory operating conditions; errors at the design stage; low quality of the used construction material; substandard work; differential settlement of walls foundation; violation or lack of wall waterproofing; natural aging of masonry and other negative factors.

In this work the object of the inspection was a brick wall of the main building of the sugar factory, which was put into operation in 1962.The inspection results showed that the condition of the load-bearing brick wall of the sugar factory main building, taking into account the scope and danger of defects, the degree of physical and moral wear of structures, as well as a number of other factors, can be considered unsatisfactory (limited working capacity) and the building can be regarded suitable for reconstruction and further operation.
Methods of day ahead load forecasting on the example of a residential area
Authors: Vasenin D N , Makarova T V , Bogatova T V , Semenova E E
Published: June 2021

The work is aimed at identifying the most effective methodology for short-term forecasting of energy consumption concerning intervals of 1 hour to 1 week based on the employment of im-proved fuzzy recurrence and long short-term memory neural networks. The object of research is a residential area with an uneven consumption of electrical energy. The article discusses methods for forecasting electrical load on the example of a residential area. The existing methods of forecasting were analyzed and the day-ahead and intra-day power forecast were reviewed. The list of relevant sources was presented.

On the basis of the reviewed literature in this area, the most effective and modern methods were identified that allow determining the consumption of electrical loads in residential and industrial buildings with an accuracy of 98 percent. Tables were developed reflecting the effectiveness of the considered techniques.

The time horizons of the forecast of electric energy consumption are considered. Four categories of load forecasting were identified: long-term forecasting with a forecast interval of more than one year; medium-term forecasting with a forecast interval from one month to one year; short-term load forecasting with a forecast interval from 1 day to several weeks.; operational forecasting, with a forecast interval from 1-2 hours to the end of the day. A comparative analysis of methods for predicting electrical load for intelligent network applications is carried out and its results are presented.
The technical options for installing solar energy systems on modern buildings
Authors: Ahmed Anees Ahmed Ahmed , Salih Mahmood Anees Ahmed Al-Shekh
Published: June 2021

Solar power is almost a good idea for home owners interested in saving money on electricity costs and supporting a healthier environment. But there’s no denying that some homes are more well suited to solar power systems than others. Your sun exposure, roof, climate, even state policies can influence how well you’ll do with a residential solar power system.

It is true that the initial cost might be a bit heavy, but it makes more economic sense in the long run. This is a onetime expenditure that serves cost free for the next thirty years or so. And about its effectiveness, people should feel comfortable that the technology itself has been proven, as a reliable and clean energy source.

This article introduces the methodology and the results of an integrated design approach to optimize both structural system and building energy performance through architectural design process. The book titled Intelligent Design using Solar-Climatic Vision, introduced a number of practical and effective design approaches towards the creation of energy-efficient building façades as well as comfortable urban environments. Applying solar-climatic vision, especially during the procedure of optimizing tall structural systems, can develop sustainable frameworks that maximize thermal comfort while minimizing waste of resources.
Wear of vibrating disc working bodies of smoothing machines
Authors: Eliseev S V , Mamaev L A , Kashuba V B , Gerasimov S N
Published: June 2021

The issues of wear of disk vibrating working bodies of smoothing machines are considered. It is shown that during friction of the working body against the concrete mixture, mainly abrasive and less oxidative wear occurs. In this case, the amount of wear is proportional to the smoothing capacity of the working body, the operating time, the specific pressure of the working body on the surface of the concrete mixture and the coefficient taking into account the working conditions. It was found that the position of natural and forced vibrations of the working body on the smoothing process leads to significant changes in the magnitude and nature of the disc wear. It was determined that the general one-sided character of the disk depends on the parameters of forced vibrations generated by the working body. The presence of localized zones with an expressed wear of the disc was revealed. The latter reduces most significantly the quality of the surface treatment of the concrete mixture. The relationship between the presence of wear of localized wear zones and natural vibrations of the metal structure of the portal of the smoothing machine is shown. It is suggested that the issues of vibration protection (vibration isolation) in the broad sense of controlling the dynamic state of the smoothing machine as a technological complex are of decisive importance for the prevention or significant reduction of local localized wear of the working body.
Expanding the capabilities of the ARCHICAD software package for effective solution of construction design tasks
Authors: Dolzhencko A V , Grebenik A V , Sedashova M A , Rudenskyi D S
Published: June 2021

Effective management of real estate complexes, which determines the minimum cost of ownership of constructed and operated objects, implies at the present stage the active introduction of information modeling technologies into the project life cycle. At the same time, in all the variety of modeling software and modeling formats offered by the national and foreign markets, those that have advanced controllability and adaptability to the changing conditions of the design or actual construction stages are the most effective for the purposes of managing the capital intensity of a non-movable asset. The ARCHICAD software package, which is a recognized leader in architectural modeling software, contains the necessary standard and additional tools for creating parameterized objects - elements of a real estate object that have the required properties, significantly accelerating and simplifying the work on adapting the model and optimizing space-planning solutions created on its basis. The authors created a universal parameterizing library feature of wall panel of precast technology in private residential construction, which implements a modular approach to parametric modeling using encapsulation basic library features to upgrade effectively the panel, to implement the specification of resources, visualize technology, including the virtual reality environment, providing the necessary visibility when training for line personnel of the construction site and technical quality control of construction products. The estimation to reduce the complexity and growth performance of work implementation of the proposed approach when designing a wall barrier of low-rise residential buildings.
Features of the implementation of the transition from a monocentric planning structure to a polycentric one on the example of Kazan
Authors: Abramova irst Nadezhda
Published: June 2021

The paper discusses the process of implementing the transition from a monocentric planning structure to a polycentric one on the example of Kazan. In addition, the theoretical concepts of polycentricity presented by the authors of papers were analyzed, as well as the methods of deduction, induction, classification and separation of concepts were used. Then a secondary analysis of the transition to a polycentric planning structure was carried out. For the analysis, the following materials were selected - a sociological survey on the assessment of the quality of life in cities on the website Domofond.ru, Strategy of socio-economic development of the municipal formation of Kazan until 2030, general plan of Kazan, reports on the implementation of national projects and municipal programs. The development of the Small Kazan Ring and the Big Kazan Ring in the city is an important step for the development of polycentricity of urban space in the concept of the city general plan.
Typology of courtyards in apartment block development based on planning openness and permeability
Authors: Matiukhin A A , Anisimova L V
Published: June 2021

In the Russian Federation, the problem of creating a comfortable urban environment is of a national nature. The authors suggest paying attention to the courtyard in apartment block development as this area is one of the most important elements of the urban environment – a buffer space between the apartment and the city. As an important criterion for a comfortable environment is its safety, therefore, it is necessary to understand which courtyards form a sense of security in people, and which do not. The formation of a sense of security of residents is influenced by many different factors. Courtyards, having a different planning arrangement, create different conditions for the comfort of living inhabitants and the degree of use by other people. The authors propose the development of a typology of courtyard spaces based on a sense of comfort and security. As basic characteristics they propose to use: planning openness of the yard, which characterizes the degree of built perimeter of the yard, as well as the permeability of the territory, indicating the accessibility of this area for other residents and their activity. This typology will be the basis for further determining how each type affects the formation of a sense of security among residents and what measures from an architectural point of view can be applied to ensure the formation of this feeling.
System of maintaining parameters of air conditioning in orthodox cathedrals
Authors: Eremkin A I , Ponomareva I K
Published: June 2021

Calculating air exchange according to existing methods, dilutions of all heat surpluses and other hazards are taken into account. This leads to a significant overestimation of the amount of supply air and saving unreasonable costs. To solve the problem of cost optimization, the authors propose a displacement ventilation and air conditioning system. In this case, the supply air is supplied to the lower zone, where the congregation is located. In this case, it is proposed to calculate the air exchange for the assimilation of only part of the heat surplus and other harmful substances entering only the lower zone, up to 2,5 meters high from the floor level. The rest of the hazards are displaced by convective flow and supply air to the upper zone and removed to the outside. The proposed solution to the problem allows you to optimize the cost of ventilation and air conditioning in the halls of worship of Orthodox churches.
Unit with a device for directional feeding of rocks with a shale structure
Authors: Romanovich M A , Romanovich A A , Chekhovskoy E I , Amini Ebrahim
Published: June 2021

The paper analyzes the properties of rocks with a shale structure, justifies the need to apply force in the direction of the lowest strength. The list of crushing equipment used in the process of obtaining cube-shaped crushed stone is given. It is established that the existing crushing equipment is not able to take into account the specific texture of the crushed materials and this does not allow obtaining cube-shaped crushed stone from shale materials. A description of the new design of the press-roll unit, which allows obtaining cuboid crushed stone from rocks with a shale structure, is given. The press-roll unit includes a device for directional feeding of shale materials to its working bodies, which create a force effect on the fed pieces of rock in the required direction. The design of the tooth of the working body is described, which allows to reduce significantly the replacement time of worn elements and reduce the bending loads acting on it. This leads to an increase in the reliability of the structure and reduces the metal consumption of repairs. A mathematical model of the directional movement of shale materials in a roll device is considered and an equation for calculating the required force is obtained. Graphical dependences of the influence of the roller installation angle and its horizontal and vertical displacement on the amount of deformation of the feed material layer are presented.
Research of technological properties of the composition of binding binders, modified with waste of processing of petroleum bituminous rocks
Authors: Kuatbayeva T K , Zhambakina Z M , Yespayeva A S , Zhakapbayeva G A
Published: June 2021

The paper deals with the issues of technology of grouting binders of silicate materials with the use of waste from the processing of petroleum bituminous rocks. The optimal compositions of grouting solutions with the use of waste from the processing of PBR were studied.

The stability of the samples in aggressive environments of low-and high-base calcium hydrosilicates was studied. Technological processes for the production of grouting binders based on waste from the processing of PBR were justified and developed.

Grouting compositions, characterized by high quality were developed. The positive effect of mixing and storage of the tested cement mixtures containing up to 50% of PBR waste with sulfate solutions of Na 2SO 4 and MgSO4 salts on the studied technical characteristics of the grouting solution and cement stone was established.

A significant result is an improvement in the setting performance, an increase in strength without a significant deterioration in the adhesion of the cement stone to the drive pipe at a 5% salt concentration.

The research results provide recommendations for the development of weighted grouting cements using technogenic materials containing an increased amount of iron oxide.
Assessment of the technical condition of intercoolers for turbocharged internal combustion engines
Authors: Sergienko S N , Mikhailov A D , Poslavsky A P , Kletsova O A
Published: June 2021

The presented work considers the analysis of methods and means for assessing the technical condition of charge air coolers in vehicles in operation. Metallographic studies of the fragments of samples, identified local sections of the heat exchanger, have been carried out. Various defects of the internal heat transfer surface, caused by the influence of operational factors, have been revealed. The article also touches upon the problem of imperfection of methods and means of instrumental control of the operating parameters of the heat exchange equipment of road transport. It is proposed to carry out diagnostics of the technical condition of heat exchangers at specialized stands equipped with an instrumentation and apparatus complex. The prospects of new developments in the field of diagnostic equipment for determining the operating characteristics of heat exchangers with the ability to measure the most important parameter - heat transfer are noted. An important addition, confirming the relevance of the chosen direction of research, is the substantiation of the value of the described developments not only as a tool for measuring the parameters of the state of heat exchangers, but also to solve the problem of predicting their residual resource. The results of the conducted research are presented. Using the method of physical modeling, an algorithm has been developed for diagnosing the technical condition of the charge air cooler in operation. Issues of provision with methods and means of diagnosing parameters of heat exchangers of vehicles in operation and repair are considered.
Factors influencing the surface quality of architectural concrete
Authors: Tsimbalyuk Y , Karpova E , Sedova A , Skripkiunas G
Published: June 2021

Architectural concrete has wide opportunities to be used both for exteriors and interiors in different buildings. Architectural concrete is the type of concrete which is usually not subjected to finishing, therefore higher standards are declared for its surface quality. According to normative documents, architectural concrete needs to have a uniform colour tone, texture, minimal defects and porosity of the surface. The present research demonstrates the concrete surface quality obtained in the course of varying different factors such as the presence of stabilizing admixture, granulometry of aggregates, usage of fly ash and workability of the concrete mixture. In the course of the research, the testing of raw materials and concrete in the fresh and hardened state were performed according to standard methodologies. The assessment of concrete surface quality was provided through the analysis of concrete surface photo 50x50 cm size. Based on the experimental results, it can be stated that better quality of the concrete surface was obtained in case of usage of gravel with two fractions of 4/16 and 2/8 and fly ash in the dosage of 25 % cement weight in the presence of plasticizing and stabilizing admixtures. The concrete mixture with high workability showed better filling of formwork and mixture particles packing on the formwork surface which led to a better quality of the concrete surface.
Impact of acid treatment on the puzzolan activity of natural zeolite tuff
Authors: Smorodinova T N , Kotvanova M K
Published: June 2021

Using the methods of thermal gravimetric analysis, and X-ray phase analysis, the puzzolan activity of the natural zeolite tuff of the Lyulinsky deposit of Khanty-Mansiysk Autonomous District -Yugra as a mineral additive to cement was evaluated. Acid modification of natural zeolite tuff was performed. The selection of modification conditions was carried out by varying the concentration of the acid solution, the time of exposure to the reagent, and the temperature. The optimal parameters were: the concentration of hydrochloric acid 3 M, the duration of acid exposure-5 hours, the temperature of 80°C. It was found that the treatment of tuff with 3M hydrochloric acid solution leads to a significant increase in puzzolan activity. The strengthening effect of the modified additive is shown. The strength of cement samples with the addition of zeolite tuff at a similar age increases by 28%. The effect of the addition of zeolite tuff on the phase composition of cement during hydration and hardening is studied. A more significant decrease in the content of portlandite was recorded when using a modified additive compared to the addition of zeolite tuff in its native state, which is consistent with the data obtained from the mass loss curves. At the same time, an increase in the content of ettringite, which contributes to the strengthening of the structure of the binder part of the cement stone, is shown. The degree of hydration of cement was estimated by the change in the content of alite. A complexometric determination of the aluminum content in the washing waters after acid treatment of zeolite tuff was carried out. It is shown that acid treatment leads to its dealuminization, which is associated with the restructuring of the zeolite framework. This, in turn, provides an increase in the number of active acid centers responsible for its adsorption properties and reactivity on the surface of the aluminum-silicate framework of the zeolite.
Wind tower based on unexploited industrial chimneys of St. Petersburg
Authors: Krasnozhen S E , Cherenkov V S , Ivanova V A , Elistratov V V
Published: June 2021

Due to the expansion of St. Petersburg from the beginning of the 20th century, the city has formed a Gray Belt of unexploited factories, some of which are architectural heritage. The modern solution to the problem of the Gray Belt is the creation of lofts and public spaces from them, however, it is also practiced transforming former factories into a site for generating “green energy”. Because of the finiteness of the extracted minerals, the use of renewable resources is the most favourable way of producing electricity. The purpose of this work is to consider the possibility of using an industrial pipe to generate energy on the example: one of the highest unexploited pipes in Grey Belt - a steamshop’s chimney (100m), built-in 1955. The result of the study is to determine the inexpediency of using the principle of a wind tube in chimneys in the Gray belt in St.Petersburg, because, based on the calculations, according to the developed method, the height required for the wind turbine to start moving is 154 m in the summertime in St. Petersburg. During the consideration of the highest pipe in the Leningrad Region (320m), there was concluded that it can provide electricity for 31 people.
Corrosion resistant fine-grained ash concrete for repairs of constructions in the linen production
Authors: Petropavlovskaya V , Sulman M , Novichenkova T , Petropavlovskii K
Published: June 2021

The article deals with the study of the compositions of corrosion-resistant concrete. They can be successfully used to prevent the destruction of structures in linen processing plants. Such plants include single workshops with an aggressive environment. Keeping retted stalks in compositions that are aggressive for structures is reflected in the condition of reinforced concrete and concrete structures of these workshops. Violation of the integrity of such structures can lead to severe environmental consequences. To eliminate such consequences, it is necessary to carry out reconstruction. Repair and reconstruction of structures must be organized through the use of innovative concrete. Such concretes must have a high density and resistance to corrosion. Analysis of information sources showed the effectiveness of using ashes with a high content of aluminosilicates. The work identified factors that determine the strength and density of concrete with the addition of ash. Based on the results of the work, recommendations were formed on the use of plasticizers. The composition of the organo-mineral complex has been developed.