scholarly journals THE RESEARCH OF THE STRUCTURE FORMATION PROCESSES OF DISPERSE MATERIALS AT THE OBTAINING OF THE COMPOSITE BUILDING MATERIALS WITH PREDETERMINED PROPERTIES

2017 ◽  
Vol 21 (5) ◽  
pp. 93-106
Author(s):  
S. N. Zolotuhin ◽  
O. B. Kukina ◽  
A. A. Abramenko ◽  
V. JA. Mishhenko ◽  
A. A. Gapeev ◽  
...  
Keyword(s):  
Structure Formation ◽  
Building Materials ◽  
Sandy Loam ◽  
Low Cost ◽  
Microscopic Analysis ◽  
Scanning Calorimetry ◽  
Thermal Methods ◽  
Water Films ◽  
Technological Methods ◽  
Automatic Diffractometer

The basic concepts of the developed theory of the structure formation of dispersed materials in the preparation of composite building materials (CBM) with predetermined properties are proposed in the article. It is shown that, in addition to laborious methods of mathematical planning, low-cost research methods, for example, thermal methods, can be used to predict the properties of CBM. The data of differential scanning calorimetry, microscopic analysis, confirming the hypothesis that the thicknesses of water films on the surface of particles of disperse systems affect the formation of nano- and microstructures of CBM are presented. On the basis of VSTU in the center of collective use of the name of Professor Yu.M. Borisov conducted a number of tests on instruments of various domestic and foreign manufacturers, such as the RAULIKD derivative, the automatic diffractometer PANalytical EMPYREAN, the X-ray diffractometer DRON-2 and others using laser diffraction, synchronous thermal analysis. On the basis of the conducted experiments, the following conclusions were made: the IPFM systems with a phosphogypsum dihydrate content of 50 ... 60%, 10% lime, sandy loam 40 ... 30% possess the best physical-mechanical properties, water absorption and softening coefficients; drying at temperatures of 60 ... 65 ° C of the obtained materials leads to a decrease in the thickness of the water films between the particles and promotes further strength growth; an understanding of the mechanism of the effect of the thickness of aqueous films on the processes of the formation of hydrate hydrophilic systems allows us to predict that various technological methods leading to a reduction in their thickness will lead to an increase in the strength and other indices of materials obtained from non-flammable technologies.

scholarly journals Analysis of structure-forming role of phosphogypsum in the production of nonfired cementless building composites

2020 ◽  
Vol 315 ◽  
pp. 07001
Author(s):  
Olga Kukina ◽  
Andrey Eremin ◽  
Dmitriy Shuvaev
Keyword(s):  
Building Materials ◽  
Test System ◽  
Chemical Plant ◽  
Simultaneous Increase ◽  
Aggregative Stability ◽  
Scanning Calorimetry ◽  
Water Films ◽  
Structure Density ◽  
Monolithic Structure

The working hypothesis is the development of the theory of disperse system aggregative stability considering the condensation processes of structure-forming of nonfired cementless building materials on the basis of phosphogypsum. The results of phisicomechanical and physicochemical analyses of Uvarovo chemical plant phosphogypsum are presented. To define the properties of phosphogypsum and phosphogypsum-based composite modern methods of analysis were applied with the use of the following equipment: the universal electromechanical test system Instron, the automatic diffractometer PANalytical EMPYREAN, the device for synchronic thermal analysis. The results of the research showed that the first endoeffects of Uvarovo chemical plant phosphogypsum have the dehydration energy of more than 200 joule/g, and they do not get lost within the time; this proves of the cementing properties of phosphogypsum. Due to the analysis of the differential scanning calorimetry results of phosphogypsum, pressed at 5 Mpa, it was found out that at the models compression the dehydration energy increases, and the correlation between the changes of water films’ thickness and dehydration energy can be observed. With the decrease of water films’ thickness we can observe the increase of dehydration energy with the simultaneous increase of the structure density and its transformation into a monolithic structure.

scholarly journals Partitions for high-rise construction using phosphogypsum

2018 ◽  
Vol 33 ◽  
pp. 02043
Author(s):  
Sergey Zolotukhin ◽  
Olga Kukina ◽  
Anatoly Abramenko
Keyword(s):  
Sandy Loam ◽  
Water Film ◽  
Production Equipment ◽  
Water Soluble ◽  
Scanning Calorimetry ◽  
Modern Material ◽  
High Rise ◽  
Water Films ◽  
Materials Used ◽  
Water Saturated

Gypsum blocks are usually used to make partitions in highrise construction. Reducing the cost of materials used in high-rise construction is an urgent task of modern material science. Phosphogypsum dihydrate, which has binding properties, is one of the large-tonnage waste. The authors have proved that, after years of storage in heaps, water-soluble phosphates, fluorides and other additives included in the structure of fresh phosphogypsum dissolved in water due to weathering (humidification-drying, freezing-thawing in a water-saturated state), and the calcium hydro-and dihydrogen phosphates ingressed in the lattice underwent complete hydrolysis and disintegration, thereby changing the physicochemical properties of phosphogypsum. The data obtained by the authors on the absence of water-soluble compounds of phosphorus, fluorine in stale phosphogypsum indicate its ecological purity and the possibility of application in housing construction. Having analyzed the data of modern methods of differential scanning calorimetry and scanning electron microscopy, the authors predicted and proved by the energy of dehydration of phosphogypsum dihydrate, lime, sandy loam, the possibility of obtaining non-flammable materials with sufficient strength for wall materials. Understanding the processes occurring in water films (the thickness of the water film, the pressure, the temperature and the pH of the aqueous extract of the mixture, the drying of the materials produced), made it possible to develop a technology for obtaining wall products from lime-sandy phosphogypsum material using typical silicate brick production equipment and vibropresses for key-cog blocks production.

Characterization of a Polymeric Membrane for the Separation of Hydrogen in a Mixture with CO2

2016 ◽  
Vol 9 (1) ◽  
pp. 126-136 ◽  
Author(s):  
Dionisio H. Malagón-Romero ◽  
Alexander Ladino ◽  
Nataly Ortiz ◽  
Liliana P. Green
Keyword(s):  
Carbon Dioxide ◽  
Hydrogen Production ◽  
Test Performance ◽  
Low Cost ◽  
Time Lag ◽  
Polymeric Membrane ◽  
Biological Processes ◽  
Scanning Calorimetry ◽  
Environmentally Sustainable ◽  
Production Of Hydrogen

Hydrogen is expected to play an important role as a clean, reliable and renewable energy source. A key challenge is the production of hydrogen in an economically and environmentally sustainable way on an industrial scale. One promising method of hydrogen production is via biological processes using agricultural resources, where the hydrogen is found to be mixed with other gases, such as carbon dioxide. Thus, to separate hydrogen from the mixture, it is challenging to implement and evaluate a simple, low cost, reliable and efficient separation process. So, the aim of this work was to develop a polymeric membrane for hydrogen separation. The developed membranes were made of polysulfone via phase inversion by a controlled evaporation method with 5 wt % and 10 wt % of polysulfone resulting in thicknesses of 132 and 239 micrometers, respectively. Membrane characterization was performed using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), atomic force microscopy (AFM), and ASTM D882 tensile test. Performance was characterized using a 23 factorial experiment using the time lag method, comparing the results with those from gas chromatography (GC). As a result, developed membranes exhibited dense microstructures, low values of RMS roughness, and glass transition temperatures of approximately 191.75 °C and 190.43 °C for the 5 wt % and 10 wt % membranes, respectively. Performance results for the given membranes showed a hydrogen selectivity of 8.20 for an evaluated gas mixture 54% hydrogen and 46% carbon dioxide. According to selectivity achieved, H2 separation from carbon dioxide is feasible with possibilities of scalability. These results are important for consolidating hydrogen production from biological processes.

INFLUENCE OF LOW-COST BUILDING MATERIALS ON HOUSING PROJECT IN REDUCTION OF HOUSING DEFICIT IN NAIROBI CITY COUNTY, KENYA

2019 ◽  
Vol 4 (2) ◽  
pp. 23-37
Author(s):  
Kamau Maina ◽  
Dr. Samson Nyang’au Paul
Keyword(s):  
Transformational Leadership ◽  
Real Estate ◽  
Building Materials ◽  
Low Cost ◽  
New Technology ◽  
Labour Productivity ◽  
Reliability And Validity ◽  
Value Theory ◽  
Modern Technology ◽  
Primary Data

Purpose: The purpose of the study was to explore the influence of low cost building materials on reduction of housing deficit in Nairobi County, Kenya.Methodology: The study adopted four theories: open innovations theory, the value theory, transformational leadership theory, and institutional theory. Methodologically, the study adopted a descriptive research design, while the population of this study was all the real estate firms registered by Kenya Property Developers Association (KPDA). Census technique was employed to collect data from all 69 real estate firms using questionnaires. Questionnaires were applied to collect primary data, where the researcher trained research assistants to aid the data collection procedure. A pilot-test was conducted as an approach to establishing both the reliability and validity assessments of the questionnaire. Statistical packages for social sciences (SPSS) was used to undertake both descriptive and inferential statistical computations.Results: The findings of the study established that the use of technology enhances the capability and capacity of construction firms to use an array of building materials. The study found that use of modern technology defined skilled labour because most organizations are leveraging technology as a basis of realizing competitive advantage. It also established that real estate firms utilize competent based human resource management firms to hire qualified personnel. In addition, it was evident that personality traits influenced adoption of new technology in the construction of low cost housing, whereas knowledge and attitudes, and skills were significantly attributed to adoption of new technology.Unique contribution to theory, practice and policy: In light of the research findings, the study recommends that organizations should leverage modern technology as a basis of realizing efficiency, effectiveness, and sustainability of projects. The study likewise recommends that organizations should build capacities to enhance labour productivity. In addition, the study recommends that organizations should adopt transformational leadership approaches as a basis of enhancing performance. The study recommends the need to revise the legal framework with a view to ensure that it reflects the changing needs of the project requirements.

Interfacial interactions between urea formaldehyde and cellulose nanofibrils (CNFs) of varying chemical composition and their impact on particle boards manufacture (PBs)

2021 ◽  
Author(s):  
Maria C. Iglesias ◽  
Philip S. McMichael ◽  
Osei A. Asafu-Adjaye ◽  
Brian K. Via ◽  
Maria S. Peresin
Keyword(s):  
Chemical Composition ◽  
Building Materials ◽  
Colloidal Stability ◽  
Low Cost ◽  
Urea Formaldehyde ◽  
Cellulose Nanofibrils ◽  
Global Market ◽  
Modulus Of Rupture ◽  
Superior Performance ◽  
Interfacial Interactions

Abstract Wood-based panels are commonly used as building materials for interior and exterior purposes. Their production and utilization have increased over the past decades due to the useful properties they present. Adhesive-bonded products make up to 80% of the wood alternatives on the global market, and of that, urea-formaldehyde (UF) makes up approximately 81% of the resins used. Formaldehyde-based resins are used due to their effectiveness and low cost, as well as their ease of application and lack of color. Nevertheless, their main disadvantages are the lack of tackiness and the emission of formaldehyde over time. To improve UF performance, the utilization of microfibrillated cellulose, has been demonstrated to be effective. However, more understanding on the mechanisms of the interactions is of relevant importance. In this work, we studied interfacial interactions between UF with bleached (BCNF) and unbleached (LCNF) cellulose nanofibrils using Quartz Crystal Microbalance with dissipation monitoring (QCM-D) technique observing the superior performance of lignin-containing CNF. Additionally, the surface free energies were investigated using Contact Angle Measurements (CA) showing a decrease of the values mainly when utilizing LCNF, which was later correlated with the wettability properties of the particle boards (PBs). PBs with different adhesive/CNF formulations were produced showing larger improvements when adding LCNF in terms of modulus of elasticity (MOE), modulus of rupture (MOR), and internal bonding (IB). To gain a better understanding on the interactions between CNF and UF, CNF was fully characterized in terms of morphology, chemical composition, charge density, as well as thermal and colloidal stability.

scholarly journals Effect of Pristine Palygorskite Powders on Explosion Characteristics of Methane-Air Premixed Gas

Energies ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2496 ◽  
Author(s):  
Yimin Zhang ◽  
Yan Wang ◽  
Ligang Zheng ◽  
Tao Yang ◽  
Jianliang Gao ◽  
...  
Keyword(s):  
Flame Propagation ◽  
Low Cost ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Flame Propagation Velocity ◽  
Explosion Pressure ◽  
Pyrolysis Characteristics ◽  
Explosion Suppression ◽  
Adsorption Desorption ◽  
Methane Explosion

In this study, pristine palygorskite powders were used as the inhibition materials to suppress the explosion of methane-air premixed gas for the first time. The composition, porosity and pyrolysis characteristics of the powders were tested by X-ray diffraction (XRD), energy dispersive spectrometry (EDS), N2 adsorption-desorption and Thermogravimetry-differential scanning calorimetry (TG-DSC) techniques. The effects of pristine palygorskite powders concentration on the explosion pressure and the average velocity of flame propagation of the 9.5% methane-air premixed gas were tested by a 20 L spherical explosion system and a 5 L pipeline explosion system. The results indicated the pristine palygorskite powders possess a considerable suppression property on methane explosion. When the mass concentration of pristine palygorskite powders was 0.20 g·L−1, the max-pressure of methane explosion was decreased by 23.9%. The methane explosion flame propagation velocity was inhibited obviously. Owing to the excellent inhibitory performance and the advantage of low-cost and environmental harmlessness, pristine palygorskite powders are potential new materials for the application on gas explosion suppression.

scholarly journals Bouwen aan jezelf door te bouwen voor een ander. Een architecturale analyse van de graven uit de noordelijke begraafplaats van Ayios Vasilios

Paleo-aktueel ◽  
2019 ◽  
pp. 11-22
Author(s):  
Youp van den Beld
Keyword(s):  
Building Materials ◽  
Low Cost ◽  
Human Interaction ◽  
Construction Process ◽  
Architectural Analysis ◽  
The North ◽  
Labour Costs ◽  
The Creation ◽  
Architectural Energetics ◽  
Architectural Unit

Building on yourself to build for another: An architectural analysis of the graves from the North Cemetery of Ayios Vasilios. For this paper I have systematically examined the construction process of the tombs from the North Cemetery of Ayios Vasilios (Laconia, Greece) using a method called architectural energetics. This method of analysis translates an architectural unit into labour costs. The calculated workhours have been combined with a precedence diagram in order to closely examine the level of human interaction, rather than to just compare labour costs. The study concludes that the transportation of the building materials that were used for the tombs was the most labour-intensive task. It also concludes that the materials that came from farthest away seem to have played the biggest role in the creation of meaning in the funerary rituals. Furthermore, two distinct strategies of construction were identified, one that focussed on scale, using low-cost materials that would have been locally available, and one that focussed on elaboration, using high-cost materials that must have come from elsewhere. The high-cost materials are theorized to have been involved in the creation of social networks among groups.

Fine structure formation and physical properties of poly(butylene terephthalate) fibres in high-speed melt spinning

e-Polymers ◽  
2003 ◽  
Vol 3 (1) ◽  
Author(s):  
Hee Lee Sun ◽  
Hou Kim Kyoung ◽  
Kikutani Takeshi ◽  
Hok Cho Hyun
Keyword(s):  
Fine Structure ◽  
Physical Properties ◽  
Structure Formation ◽  
High Speed ◽  
Melt Spinning ◽  
Mechanical Analysis ◽  
Scanning Calorimetry ◽  
Butylene Terephthalate ◽  
Initial Modulus ◽  
Higher Temperature

Abstract Poly(butylene terephthalate) (PBT) fibres were obtained by high-speed melt spinning up to a take-up velocity of 8 km/min. Fine structure formation and physical properties of these fibres were investigated. The increase of take-up velocity caused raises in both density and birefringence. In wide-angle X-ray diffraction equatorial profiles, the increase of take-up velocity can be observed in the (010) and (100) reflections of β-crystals; the reflection peaks are the sharpest at a take-up velocity of 6 km/min. The initial modulus of the fibres arises when the fraction of β-crystals is increased, while the tenacity depends more on the fraction of α-crystals, i.e., the total crystallinity. Thermal properties of high-speed spun PBT fibres were measured with differential scanning calorimetry, dynamic mechanical and thermo-mechanical analysis, etc. Endothermic curves become sharper with increasing take-up velocity, and endothermic melting peaks are shifted to higher temperature. Crystal structures are well developed in fibres obtained at higher take-up velocities. The tan δ peaks of PBT fibres tend to shift to higher temperature and the peak intensity is decreased with increasing take-up velocity, i.e., the packing density of PBT fibres is high when the take-up velocity and thus the orientation of amorphous regions is increased. The shrinkage has a tendency to decrease with increasing take-up velocity.

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