scholarly journals INFLUENCE OF THE TYPE OF WATER ACTIVATION ON THE CONTACT ZONE BETWEEN THE FILLER AND THE CEMENT STONE

2021 ◽  
pp. 16-25
Author(s):  
Alexandra Shyshkina ◽  
Alexandеr Shyshkin
Keyword(s):  
Cement Paste ◽  
Chemical Activation ◽  
High Rate ◽  
Cement Stone ◽  
Normal Density ◽  
Alkaline Water ◽  
Fine Grained ◽  
Low Concentrations ◽  
Water Activation ◽  
The Many

Among the many ways to improve the preparation of concrete mix is to modify the properties of cement systems by mechanical, physical, chemical and combined effects. One of the directions of activation of the concrete mixture is the activation of its components, namely: electromagnetic, electrochemical and physics-chemical activation of mixing water. The most accessible and technological of them is the physics-chemical activation of water and aqueous solutions by certain organic substances used in ultra-low concentrations, followed by their use as a mixing fluid for building mixtures. The purpose of the study was to perform a comparative assessment of the effect of electromagnetic, electrochemical and physicochemical activation of water on the properties of cement paste and fine-grained concrete. To achieve this goal, the degree of influence ofelectromagnetic, electrochemical and physicochemical activation of water on the contraction and hardening time of cement paste, as well as the degree of influence of electromagnetic, electrochemical and physicochemical activation of water on compressive strength of fine concrete. It is established that the type of activation of kneading water affects the hardening time of the cement paste and the normal density. The shortest hardening times are set for cement paste, which is obtained on electrochemically activated alkaline water, and the longest with the use of physics-chemical activation. At the same time, the highest strength at the lowest contraction has concrete, which is obtained on physics-chemical activated water. This concrete has the highest rate of strength. Concretes obtained on «alkaline» water, after its electro-chemical activation, have a high rate of strength formation and its value, but high contraction, which leads to cracking of concrete.

Crucial role of physiotherapy in treating COVID-19 patients

2020 ◽  
Vol 11 (SPL1) ◽  
pp. 967-971
Author(s):  
Poonam Thakre ◽  
Waqar M. Naqvi ◽  
Trupti Deshmukh ◽  
Nikhil Ingole ◽  
Sourabh Deshmukh
Keyword(s):  
Public Health ◽  
Distress Syndrome ◽  
Public Health Problem ◽  
Public Health Emergency ◽  
High Rate ◽  
Major Public Health Problem ◽  
Front Line ◽  
The Many ◽  
Sixth International

The emergence in China of 2019 of severe acute respiratory syndrome coronavirus2 (SARS-CoV-2) previously provisionally names 2019-nCoV disease (COVID19) caused major global outbreak and is a major public health problem. On 30 January 2020, the WHO declared COVID19 to be the sixth international public health emergency. This present pandemic has engrossed the globe with a high rate of mortality. As a front line practitioner, physiotherapists are expected to be getting in direct contact with patients infected with the virus. That’s why it is necessary for understanding the many aspects of their role in the identification, contains, reduces and treats the symptoms of this disease. The main presentation is the involvement of respiratory system with symptoms like fever, cough, sore throat, sneezing and characteristics of pneumonia leads to ARDS(Acute respiratory distress syndrome) also land up in multiorgan dysfunction syndrome. This text describes and suggests physiotherapy management of acute COVID-19 patients. It also includes recommendations and guidelines for physiotherapy planning and management. It also covers the guidelines regarding personal care and equipment used for treatment which can be used in the treatment of acute adult patients with suspected or confirmed COVID-19.

Experiments on high rate effluent filtration in the Netherlands

1998 ◽  
Vol 38 (3) ◽  
pp. 127-134
Author(s):  
Jaap H. J. M. van der Graaf ◽  
Arjen F. van Nieuwenhuijzen
Keyword(s):  
Wastewater Treatment ◽  
The Netherlands ◽  
Suspended Solids ◽  
Practical Experience ◽  
High Rate ◽  
Treated Water ◽  
Low Concentrations ◽  
Wastewater Treatment Effluent

As yet, filtration of wastewater treatment effluent has not been practised in the Netherlands. The main objections were the expected high costs. In order to gain practical experience an investigation programme studied the applicability and optimization of effluent filtration. Especially multi-layer filtration with the addition of ironchloride seemed to be very effective. Very low concentrations of suspended solids and phosphorus were achieved, even at high filtration rates (up to 30 m/h). This leads to an impressive reduction of expected costs, down to Dfl. 0.02/m3 (treated water).

scholarly journals Effects of the Translocation Status of Human Immunodeficiency Virus Type 1 Reverse Transcriptase on the Efficiency of Excision of Tenofovir

2007 ◽  
Vol 51 (8) ◽  
pp. 2911-2919 ◽  
Author(s):  
Bruno Marchand ◽  
Kirsten L. White ◽  
John K. Ly ◽  
Nicolas A. Margot ◽  
Ruth Wang ◽  
...  
Keyword(s):  
Human Immunodeficiency Virus ◽  
Complex Formation ◽  
Reverse Transcriptase ◽  
High Rate ◽  
Human Immunodeficiency Virus Replication ◽  
Degree Of Protection ◽  
Cellular Environment ◽  
Dead End ◽  
Low Concentrations ◽  
Immunodeficiency Virus

ABSTRACT The ATP-dependent phosphorolytic excision of nucleoside analogue reverse transcriptase inhibitors can diminish their inhibitory effects on human immunodeficiency virus replication. Previous studies have shown that excision can occur only when the reverse transcriptase complex exists in its pretranslocational state. Binding of the next complementary nucleotide causes the formation of a stable dead-end complex in the posttranslocational state, which blocks the excision reaction. To provide mechanistic insight into the excision of the acyclic phosphonate nucleotide analog tenofovir, we compared the efficiencies of the reaction in response to changes in the translocation status of the enzyme. We found that rates of excision of tenofovir with wild-type reverse transcriptase can be as high as those seen with 3′-azido-3′-deoxythymidine monophosphate (AZT-MP). Thymidine-associated mutations, which confer >100-fold and 3-fold decreased susceptibility to AZT and tenofovir, respectively, caused substantial increases in the efficiency of excision of both inhibitors. However, in contrast to the case for AZT-MP, the removal of tenofovir was highly sensitive to dead-end complex formation. Site-specific footprinting experiments revealed that complexes with AZT-terminated primers exist predominantly pretranslocation. In contrast, complexes with tenofovir-terminated primers are seen in both configurations. Low concentrations of the next nucleotide are sufficient to trap the complex posttranslocation despite the flexible, acyclic character of the compound. Thus, the relatively high rate of excision of tenofovir is partially neutralized by the facile switch to the posttranslocational state and by dead-end complex formation, which provides a degree of protection from excision in the cellular environment.

scholarly journals POROSITY PARAMETERS OF CEMENT STONE CONTAINING CHEMICAL ADMIXTURES OF DIFFERENT PURPOSE / CEMENTINIO AKMENS SU SKIRTINGOS PASKIRTIES CHEMINIAIS PRIEDAIS PORINGUMO RODIKLIAI

2013 ◽  
Vol 5 (5) ◽  
pp. 530-535
Author(s):  
Lukas Venčkauskas ◽  
Mindaugas Daukšys
Keyword(s):  
Cement Paste ◽  
Cement Stone ◽  
Hardened Cement ◽  
Closed Porosity ◽  
Hardened Cement Paste ◽  
Chemical Admixtures ◽  
Average Size ◽  
The Impact ◽  
Plasticizing Admixture

The conducted research has established a complex influenceand the impact of separate chemical admixtures of differentpurpose on the parameters of the porosity of hardened cementpaste such as open and closed porosity, the average size of poresand the rates of pore inequality. According to the parametersof the porosity of hardened cement paste, on the basis of A. E.Sheikin’s methodology, the number of freezing-thawing cycleswas predicted. This research used plasticizing, viscosity modifyingand antifoaming admixtures. It has been found that, when theamount of plasticizing admixture in cement paste (W/C–0.45) isconstant and makes 1.1% of the cement mass, and the amountof viscosity modifying and antifoaming the admixture increasesfrom 0.1 to 0.6% and from 0.05 to 0.3% respectively, the openporosity of hardened cement paste varies between 30.21% and31.06%, while closed porosity varies between 5.39% and 6.22%.When the amount of the plasticizing admixture in cement paste(W/C–0.45) exceeds 1.1% of the cement mass, the open porosityof hardened cement paste increases by 1.4 times and closedporosity decreases by 2.5 times. While adding 0.1% of the viscositymodifying admixture to cement paste, the open porosityof hardened cement paste is increased by 1.5 times and closedporosity decreases by 2.4 times. The amount of 0.05% of thecement mass of the antifoaming admixture results in the increasedopen porosity of hardened cement paste by 1.5 times and reducedclosed porosity by 3.5 times. Santrauka Tyrimo metu nustatyta kompleksinė bei atskirų skirtingos paskirties cheminių priedų įtaka cementinio akmens poringumo rodikliams – atvirajam ir uždarajam poringumui, vidutinio porų dydžio ir porų vienodumo rodikliams. Tyrimuose naudoti cheminiai priedai: plastifikuojantis, klampą modifikuojantis ir mišinyje susiformavusias oro poras suardantis priedas. Nustatyta, kad cemento tešloje (V/C – 0,45) esant pastoviam plastifikuojančio priedo kiekiui – 1,0 % cemento masės, klampą modifikuojančio priedo kiekiui kintant nuo 0,1 iki 0,6 %, o mišinyje susiformavusias oro poras suardančio priedo kiekiui kintant nuo 0,05 iki 0,3 %, cementinio akmens atvirasis poringumas svyruoja nuo 30,21 iki 31,06 %, o uždarasis – nuo 5,39 iki 6,22 %. Cemento tešloje viršijus plastifikuojančio priedo 1,1 % cemento masės, cementinio akmens atvirasis poringumas padidėja apie 1,4 karto, o uždarasis poringumas sumažėja apie 2,5 karto. Pridėjus į tešlą 0,1 % cemento masės klampą modifikuojančio priedo, cementinio akmens atvirasis poringumas padidėja apie 1,5 karto, uždarasis poringumas sumažėja apie 2,4 karto. Oro poras suardančio priedo kiekis 0,05 % cemento masės cementinio akmens atvirąjį poringumą padidina apie 1,5 karto, uždarąjį poringumą sumažina apie 3,5 karto.

Influence of High-Calcium Ash Composition on the Composite Binders’ Properties

2021 ◽  
Vol 316 ◽  
pp. 1019-1024
Author(s):  
O. A. Ignatova ◽  
A. A. Dyatchina
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Cement Stone ◽  
Normal Density ◽  
Fine Aggregate ◽  
Equivalent Amount ◽  
High Calcium ◽  
Composition Structure ◽  
Kinetics Of ◽  
Positive Effect

The paper presents the studies’ results of chemical composition, structure, and physico-mechanical properties of high-calcium ashes from the Kansk-Achinsk coals (2017-2019 selection). It was found that ash has a complex poly-mineral composition and contains hydraulically active minerals and oxides of СаОfr, β-C2S, CA, C3A, C4AF, C2F, CaSO4. According to the content of CaOfr, MgO does not meet standards’ requirements. The uniformity of the volume change is maintained by the composition with 50% of cement. The structure and hardening kinetics of ash and ash-cement stone compositions, obtained from the test of normal density, were analyzed. It was established that the hardening of compositions with ash from the Kansk-Achinsk coals was largely influenced by ash minerals. An equivalent amount of cement in composite binders cannot be replaced. In order to obtain a positive effect, compositions with ash instead cement of no more than 30% and a part of fine aggregate, without exceeding the ratio of ash: cement = 1: 1, should be used.

scholarly journals THE ESTIMATION METHODS OF MICROFILLERS INFLUENCE ON CEMENT STONE PROPERTIES/MIKROUŽPILDŲ ĮTAKOS CEMENTINIO AKMENS SAVYBĖMS ANALITINIO ĮVERTINIMO PRINCIPAI

1997 ◽  
Vol 3 (10) ◽  
pp. 69-75
Author(s):  
Juozas Deltuva ◽  
Žymantas Rudžionis
Keyword(s):  
Relative Density ◽  
Silica Fume ◽  
Cement Paste ◽  
Heterogeneous Material ◽  
Estimation Methods ◽  
Cement Stone ◽  
Structural Element ◽  
Regular Form ◽  
Amorphous Sio2 ◽  
Hardening Process

The concrete and cement microfillers are materials of different fineness, such as wastes of production or pulverized rocks. According to their influence on cement hardening process, they may be classified into inert microfillers or chemically active ones. The chemically active microfillers, such as silica fume, fly ashes and others, have more then 50% amorphous SiO2, that takes part in cement hardening process. Inert microfillers, such as granite, dolomite, sand dust and others, in most cases have no influence on the cement hydration. The usage of microfillers in concrete is common, but so far no clear dependence between the quantity of added microfillers and properties of concrete has been established. One of possible ways to estimate the microfillers influence on the products with cement binder is the structural element method. The structural element is the smallest cell, approximated to a spatial figure of regular form, that has all components with the same proportions, as in all the volume of heterogeneous material. The essence of this method is to divide the mix in to bigger particles, that are named “nuclei” of structural elements and take 50% of all mix volume, and smaller particles, that form cover layers of the nuclei and make up the rest of the volume of the mix. The dependence between the relative density of loose materials and relation (1) between the diameters of the bigger and smaller particles of the structural element has been estimated. This relation is changed when microfillers are added to the cement. There is a possibility to optimize relative density by (2), (3) and (4) relations, if the granulometric composition of the cement and microfillier is known. The experimental and calculated results of this optimization are shown in Table 1. The properties of pressed cement stone with inert microfillers admixture are presented in Table 2. Formulae for calculating the relative density (8) and compressive strength (11) of hardening cement have been estimated. The chemically active microfillers, such as silica fume, interact with Ca(OH)2 and form new CSH. The density and strength of cement stone increased after this interaction. The influence of chemically active microfillers on the relative density of the cement stone is given in (12). The density of cement stone increases to 4.5% and strength increases to 40.2%, if the quantity of inert microfillers in the cement paste reaches 10%. The density of cement stone increases to 7.4% and strength increases to 54.7%, if the quantity of chemically active microfillers in the cement paste reaches 10%.

Transepithelial movement of calcium in crustaceans

1993 ◽  
Vol 184 (1) ◽  
pp. 1-16 ◽  
Author(s):  
D. S. Neufeld ◽  
J. N. Cameron
Keyword(s):  
Active Transport ◽  
Calcium Concentration ◽  
Cellular Mechanism ◽  
The Body ◽  
High Rate ◽  
Calcium Flux ◽  
Moult Cycle ◽  
Electrochemical Gradient ◽  
Low Concentration ◽  
Low Concentrations

The regulation of calcium in most crustaceans is especially challenging owing to the highly mineralized cuticle that must be recalcified after each moult, a process that often occurs in environments with low concentrations of calcium. The gill and carapace epithelia separate the major calcium-containing compartments of the body and therefore see large changes in the rate of calcium flux through the moult cycle. Large changes in the ultrastructure of these cells do not, however, correlate well with the periods of calcium movement and probably reflect other physiological events. Despite the challenges to regulating calcium levels at various acclimation salinities and moult stages, the calcium concentration in the blood is maintained relatively constant. There is a rapid increase to a high rate of calcium flux across both the gill and carapace epithelium shortly after the moult; on an area-specific basis these fluxes are among the highest reported for calcium-transporting epithelia. When in water with a very low concentration of calcium, the electrochemical gradient for calcium is directed outwards and net influx must occur by active transport. Evidence suggests that changes in the electrochemical gradient, permeability and active transport are all important in the ability of crustaceans to take up calcium from water with a low concentration of this ion. Although an enzyme transporter is presumably involved in the active transport of calcium across epithelia, very little is known about the cellular mechanism of the transepithelial movement of calcium in crustaceans.

Networked Operations

2014 ◽  
pp. 49-70
Author(s):  
E. J. de Waard
Keyword(s):  
Organizational Design ◽  
Task Force ◽  
Control Process ◽  
Command And Control ◽  
Military Organizations ◽  
Fine Grained ◽  
Network Centric Operations ◽  
The Many ◽  
Human Actors ◽  
And Control

Decentralized, peer-to-peer command and control is a key principle of network-centric operations that has received a lot of scholarly attention. So far, robust networking, another principle, has remained rather underexposed in the academic debate. This chapter introduces theory on modular organizing to start a discourse on network robustness from an organizational design perspective. Above all, the chapter makes clear that the level of system decomposition influences the command and control process of composite military structures. When military organizations follow a fine-grained modularization approach, the structure of a task force deployed may become complex, asking for extra coordination mechanisms to achieve syntheses between the many contributing functional organizational components. In addition, it is argued that modularity's principle of near-decomposability has to be incorporated into the available mathematical models on network-centric operations. A point of concern, in this respect, is that the current modeling parameters make no clear distinction between the different types of actors—or nodes—in a military network structure, whereas in reality, technological, organizational, and human actors all live by their own specific rules.

scholarly journals From embracing to managing risks

BMJ Open ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. e022921 ◽  
Author(s):  
Justin Keen ◽  
Emma Nicklin ◽  
Nyantara Wickramasekera ◽  
Andrew Long ◽  
Rebecca Randell ◽  
...  
Keyword(s):  
Real Time ◽  
Middle Managers ◽  
Safety Information ◽  
Active Management ◽  
Management Systems ◽  
Quality Of Data ◽  
Fine Grained ◽  
Information Infrastructures ◽  
The Many ◽  
Board Level

ObjectiveTo assess developments over time in the capture, curation and use of quality and safety information in managing hospital services.SettingFour acute National Health Service hospitals in England.Participants111.5 hours of observation of hospital board and directorate meetings, and 72 hours of ward observations. 86 interviews with board level and middle managers and with ward managers and staff.ResultsThere were substantial improvements in the quantity and quality of data produced for boards and middle managers between 2013 and 2016, starting from a low base. All four hospitals deployed data warehouses, repositories where datasets from otherwise disparate departmental systems could be managed. Three of them deployed real-time ward management systems, which were used extensively by nurses and other staff.ConclusionsThe findings, particularly relating to the deployment of real-time ward management systems, are a corrective to the many negative accounts of information technology implementations. The hospital information infrastructures were elements in a wider move, away from a reliance on individual professionals exercising judgements and towards team-based and data-driven approaches to the active management of risks. They were not, though, using their fine-grained data to develop ultrasafe working practices.

Effect of process parameters on the microstructure evolution of laser surface quenched Ni-Al bronze

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040029
Author(s):  
Zhenbo Qin ◽  
Da-Hai Xia ◽  
Yida Deng ◽  
Wenbin Hu ◽  
Zhong Wu
Keyword(s):  
Grain Boundary ◽  
Process Parameters ◽  
Microstructure Evolution ◽  
Laser Scanning ◽  
Threshold Value ◽  
Laser Surface ◽  
High Rate ◽  
Fine Grained ◽  
Surface Quenching ◽  
Overlap Ratio

Laser surface quenching technology was used to modify the surface microstructure of as-cast Ni-Al bronze (NAB). The modified microstructure was studied by scanning electron microscopy (SEM), and the effect of laser process parameters on microstructure evolution was investigated. It was found that a fine-grained zone with fully [Formula: see text] phase microstructure formed on the surface of NAB. The depth of the fine-grained zone increased with the increase of laser power, and surface melting occurred when the power reached a threshold value. Laser scanning at a low rate caused the coarsening of grain boundary, while too high rate led to incomplete quenching. Spot overlap ratio determined the microstructure of the superimposed area, and unsuitable ratio would cause bulky [Formula: see text] precipitation at the grain boundary or incomplete transformation from [Formula: see text] phase to [Formula: see text] phase.

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