The impact of variation in chemical and physical properties of PFA and BPD semi-dry cement paste on strength properties

The polycarboxylate-type superplasticizers (PCS) modified by sulfonic group were prepared. The influence of sulfonic group content on the performance of cement admixtures when using sulfonic group modified PCS was discussed. Some physical properties such as dispersion, cement paste fluidity, mortar fluidity, compressive strength ratio and flexural strength ratio were investigated. The results show that when using PCS with sulfonic group content 20%~25% (mol/mol of total carboxyl group), the dispersion and fluidity of concrete can be distinctly improved, meanwhile the strength properties can be maintained.

Download Full-text

MAGNESIUM ZK61A

Alloy Digest ◽

10.31399/asm.ad.mg0067 ◽

1969 ◽

Vol 18 (10) ◽

Keyword(s):

Corrosion Resistance ◽

Physical Properties ◽

Tensile Properties ◽

Room Temperature ◽

Heat Treating ◽

Strength Properties ◽

Casting Alloy ◽

Chemical Company ◽

Casting Alloys ◽

Magnesium Casting

Abstract Magnesium ZK61A is a heat treatable sand casting alloy offering higher strength properties for room-temperature applications than other magnesium casting alloys. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, and joining. Filing Code: Mg-67. Producer or source: The Dow Chemical Company.

Download Full-text

Evaluation of Hydraulic Fracturing Models and Their Limitations to Predict No-Drill Zones for Horizontal Directional Drilling

Volume 2: Pipeline Safety Management Systems; Project Management, Design, Construction, and Environmental Issues; Strain Based Design; Risk and Reliability; Northern Offshore and Production Pipelines ◽

10.1115/ipc2018-78304 ◽

2018 ◽

Author(s):

Saeed Delara ◽

Kendra MacKay

Keyword(s):

Hydraulic Fracturing ◽

Safety Factor ◽

Standard Procedure ◽

Accurate Determination ◽

Strength Properties ◽

Analytical Models ◽

Alternative Methods ◽

Directional Drilling ◽

Horizontal Directional Drilling ◽

The Impact

Horizontal directional drilling (HDD) has become the preferred method for trenchless pipeline installations. Drilling pressures must be limited and a “no-drill zone” determined to avoid exceeding the strength of surrounding soil and rock. The currently accepted industry method of calculating hydraulic fracturing limiting pressure with application of an arbitrary safety factor contains several assumptions that are often not applicable to specific ground conditions. There is also no standard procedure for safety factor determination, resulting in detrimental impacts on drilling operations. This paper provides an analysis of the standard methods and proposes two alternative analytical models to more accurately determine the hydraulic fracture point and acceptable drilling pressure. These alternative methods provide greater understanding of the interaction between the drilling pressures and the surrounding ground strength properties. This allows for more accurate determination of horizontal directional drilling limitations. A comparison is presented to determine the differences in characteristics and assumptions for each model. The impact of specific soil properties and factors is investigated by means of a sensitivity analysis to determine the most critical soil information for each model.

Download Full-text

Evaluation of the Impact of Organic Fillers on Selected Properties of Organosilicon Polymer

Polymers ◽

10.3390/polym13071103 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1103

Author(s):

Sara Sarraj ◽

Małgorzata Szymiczek ◽

Tomasz Machoczek ◽

Maciej Mrówka

Keyword(s):

Tensile Strength ◽

Natural Fiber ◽

Accelerated Aging ◽

Strength Properties ◽

Visual Observation ◽

Walnut Shell ◽

Pistachio Shell ◽

Thermoplastic Matrix ◽

Static Tensile ◽

The Impact

Eco-friendly composites are proposed to substitute commonly available polymers. Currently, wood–plastic composites and natural fiber-reinforced composites are gaining growing recognition in the industry, being mostly on the thermoplastic matrix. However, little data are available about the possibility of producing biocomposites on a silicone matrix. This study focused on assessing selected organic fillers’ impact (ground coffee waste (GCW), walnut shell (WS), brewers’ spent grains (BSG), pistachio shell (PS), and chestnut (CH)) on the physicochemical and mechanical properties of silicone-based materials. Density, hardness, rebound resilience, and static tensile strength of the obtained composites were tested, as well as the effect of accelerated aging under artificial seawater conditions. The results revealed changes in the material’s properties (minimal density changes, hardness variation, overall decreasing resilience, and decreased tensile strength properties). The aging test revealed certain bioactivities of the obtained composites. The degree of material degradation was assessed on the basis of the strength characteristics and visual observation. The investigation carried out indicated the impact of the filler’s type, chemical composition, and grain size on the obtained materials’ properties and shed light on the possibility of acquiring ecological silicone-based materials.

Download Full-text

Comparison of Osmotic Resistance, Shape and Transmembrane Potential of Erythrocytes Collected from Healthy and Fed with High Fat-Carbohydrates Diet (HF-CD) Pigs—Protective Effect of Cistus incanus L. Extracts

Materials ◽

10.3390/ma14041050 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1050

Author(s):

Sylwia Cyboran-Mikołajczyk ◽

Robert Pasławski ◽

Urszula Pasławska ◽

Kacper Nowak ◽

Michał Płóciennik ◽

...

Keyword(s):

Biological Activity ◽

Physical Properties ◽

Plasma Lipid ◽

Membrane Lipid ◽

Osmotic Resistance ◽

High Fat ◽

Atherosclerotic Lesions ◽

Cistus Incanus ◽

Osmotic Resistance Of Erythrocytes ◽

The Impact

Long-term high fat-carbohydrates diet (HF-CD) contributes to the formation of irreversible changes in the organism that lead to the emergence of civilization diseases. In this study, the impact of three-month high-fat diet on the physical properties of erythrocytes (RBCs) was studied. Furthermore, the biological activity of Cistus incanus L. extracts, plant known with high pro-health potential, in relation to normal and HF-CD RBCs, was determined. Obtained results have shown that, applied HF-CD modified shape, membrane potential and osmotic resistance of erythrocytes causing changes in membrane lipid composition and the distribution of lipids. The impact of HF-CD on physical properties of RBCs along with atherosclerotic lesions of the artery was visible, despite the lack of statistically significant changes in blood morphology and plasma lipid profile. This suggests that erythrocytes may be good markers of obesity-related diseases. The studies of biological activity of Cistus incanus L. extracts have demonstrated that they may ameliorate the effect of HF-CD on erythrocytes through the membrane-modifying and antioxidant activity.

Download Full-text

Single Crystal Growth and Physical Properties of Pyroxene CoGeO3

Crystals ◽

10.3390/cryst11040378 ◽

2021 ◽

Vol 11 (4) ◽

pp. 378

Author(s):

Li Zhao ◽

Zhiwei Hu ◽

Hanjie Guo ◽

Christoph Geibel ◽

Hong-Ji Lin ◽

...

Keyword(s):

High Pressure ◽

Magnetic Properties ◽

Magnetic Susceptibility ◽

Crystal Growth ◽

Physical Properties ◽

Single Crystal ◽

Single Crystals ◽

Magnetic Moments ◽

Single Crystal Growth ◽

The Impact

We report on the synthesis and physical properties of cm-sized CoGeO3 single crystals grown in a high pressure mirror furnace at pressures of 80 bar. Direction dependent magnetic susceptibility measurements on our single crystals reveal highly anisotropic magnetic properties that we attribute to the impact of strong single ion anisotropy appearing in this system with TN∼33.5 K. Furthermore, we observe effective magnetic moments that are exceeding the spin only values of the Co ions, which reveals the presence of sizable orbital moments in CoGeO3.

Download Full-text

NEOShield - A global approach to NEO Impact Threat Mitigation

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314011843 ◽

2012 ◽

Vol 10 (H16) ◽

pp. 478-479

Author(s):

Patrick Michel ◽

Keyword(s):

European Union ◽

Physical Properties ◽

Technological Development ◽

Numerical Models ◽

Physical Contact ◽

International Strategy ◽

The European Union ◽

Design Development ◽

Asteroid Deflection ◽

The Impact

AbstractNEOShield is a European-Union funded project coordinated by the German Aero-space Center, DLR, to address near-Earth object (NEO) impact hazard mitigation issues. The NEOShield consortium consists of 13 research institutes, universities, and industrial partners from 6 countries and includes leading US and Russian space organizations. The project is funded for a period of 3.5 years from January 2012 with a total of 5.8 million euros. The primary aim of the project is to investigate in detail promising mitigation techniques, such as the kinetic impactor, blast deflection, and the gravity tractor, and devise feasible demonstration missions. Options for an international strategy for implementation when an actual impact threat arises will also be investigated.The NEOShield work plan consists of scientific investigations into the nature of the impact hazard and the physical properties of NEOs, and technical and engineering studies of practical means of deflecting NEOs. There exist many ideas for asteroid deflection techniques, many of which would require considerable scientific and technological development. The emphasis of NEOShield is on techniques that are feasible with current technology, requiring a minimum of research and development work. NEOShield aims to provide detailed designs of feasible mitigation demonstration missions, targeting NEOs of the kind most likely to trigger the first space-based mitigation action.Most of the asteroid deflection techniques proposed to date require physical contact with the threatening object, an example being the kinetic impactor. NEOShield includes research into the mitigation-relevant physical properties of NEOs on the basis of remotely-sensed astronomical data and the results of rendezvous missions, the observational techniques required to efficiently gather mitigation-relevant data on the dynamical state and physical properties of a threatening NEO, and laboratory investigations using gas guns to fire projectiles into asteroid regolith analog materials. The gas-gun investigations enable state-of-the-art numerical models to be verified at small scales. Computer simulations at realistic NEO scales are used to investigate how NEOs with a range of properties would respond to a pulse of energy applied in a deflection attempt. The technical work includes the development of crucial technologies, such as the autonomous guidance of a kinetic impactor to a precise point on the surface of the target, and the detailed design of realistic missions for the purpose of demonstrating the applicability and feasibility of one or more of the techniques investigated. Theoretical work on the blast deflection method of mitigation is designed to probe the circumstances in which this last line of defense may be the only viable option and the issues relating to its deployment. A global response campaign roadmap will be developed based on realistic scenarios presented, for example, by the discovery of an object such as 99942 Apophis or 2011 AG5 on a threatening orbit. The work will include considerations of the timeline of orbit knowledge and impact probability development, reconnaissance observations and fly-by or rendezvous missions, the political decision to mount a mitigation attempt, and the design, development, and launch of the mitigation mission. Collaboration with colleagues outside the NEOShield Consortium involved in complementary activities (e.g. under the auspices of the UN, NASA, or ESA) is being sought in order to establish a broad international strategy.We present a brief overview of the history and planned scope of the project, and progress made to date.The NEOShield project (http://www.neoshield.net) has received funding from the European Union Seventh Framework Program (FP7/2007-2013) under Grant Agreement no. 282703.

Download Full-text

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

Mokslas - Lietuvos ateitis ◽

10.3846/mla.2013.83 ◽

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.

Download Full-text

Microstructure and Mechanical Properties of Modern 11%Cr Heat-Resistant Steel Weld Joints

Materials ◽

10.3390/ma14123430 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3430

Author(s):

Grzegorz Golański ◽

Jacek Słania ◽

Marek Sroka ◽

Paweł Wieczorek ◽

Michał Urzynicok ◽

...

Keyword(s):

Mechanical Properties ◽

Welded Joints ◽

Martensitic Steel ◽

Base Material ◽

Hardness Measurement ◽

Power Industry ◽

Strength Properties ◽

Typical Structure ◽

Δ Ferrite ◽

The Impact

In addition to good high-temperature creep resistance and adequate heat resistance, steels for the power industry must have, among other things, good weldability. Weldability of such steels is one of the criteria determining whether or not the material is suitable for applications in the power industry. Therefore, when materials such as martensitic steel Thor 115 (T115) are introduced into the modern power industry, the quality and properties of welded joints must be assessed. The paper presents the results of metallographic and mechanical investigations of T115 martensitic steel welded joints. The analysis was carried out on joints welded with two filler metals: WCrMo91 (No. 1) and EPRI P87 (No. 2). The scope of the investigations included: microstructural investigations carried out using optical, scanning and transmission electron microscopy and mechanical testing, i.e., Vickers microhardness and hardness measurement, static tensile test and impact test. The macro- and microstructural investigations revealed correct structure of the weld, without welding imperfections. The microstructural investigations of joint No. 1 revealed a typical structure of this type of joint, i.e., the martensitic structure with numerous precipitates, while in joint No. 2, the so-called Nernst’s layers and δ-ferrite patches were observed in the weld fusion zone as well as the heat affected zone (HAZ). The mechanical properties of the test joints met the requirements for the base material. A slight influence of the δ-ferrite patch on the strength properties of joint No. 2 was observed, and its negative effect on the impact energy of HAZ was visible.

Download Full-text