scholarly journals ADDITIVES FOR HEAVY CONCRETE BASED ON INDUSTRIAL WASTE FROM CHEMICAL INDUSTRIES

2021 ◽  
Vol 64 (4) ◽  
pp. 104-109
Author(s):  
Igor V. Polyakov ◽  
Mikhail V. Barannikov ◽  
Ekaterina A. Stepanova
Keyword(s):  
Research Work ◽  
Water Soluble ◽  
Concrete Mixture ◽  
Crystalline Hydrate ◽  
Cement Stone ◽  
Wetting Properties ◽  
Concrete Mixtures ◽  
Complex Additive ◽  
Corrosion Of Steel ◽  
Concrete Hardening

The effect of a complex additive containing superplasticizer C-3 on the properties of heavy concrete has been investigated. The efficiency of the plasticizing action of the specified additive at the stage of preparation of the concrete mixture and subsequent molding of concrete products has been revealed. It is proved that at the stage of concrete hardening, the investigated additive promotes to the formation of a more homogeneous colloidal-crystalline structure and the formation of dense crystalline hydrate complexes of cement stone by the time of completion of concrete hardening. The objects of investigation were samples of grade B22.5 concrete without additives; containing a monoadditive - superplasticizer S-3; containing the complex additive. When designing the composition of additives for heavy concrete, we proceeded from the fundamental provisions of construction science that the complexity of the action of additives lies in the optimal combination of two main opposite processes in time and volume of the concrete matrix. The use of the caprolactam oligomer synthesized in the course of this investigation makes it possible to solve the problem of involving concentrated wastes of caprolactam production in the production turnover. The obtained caprolactam oligomers can be used in construction as plasticizers of concrete mixtures, as inhibitors of corrosion of steel reinforcement in the production of reinforced concrete products. Water-soluble oligomers of caprolactam, which reduce the time of dissolution of the superplasticizer C-3 and the dispersion of low-temperature catalyst in the volume of the concrete mixture being mixed, were synthesized. It was found that in the presence of the oligomer caprolactam in an amount of 10 to 20% of the mass. the dissolution rate of S-3 superplasticizer in water at a temperature of 20-21 °C increases by 2.0-2.2 times. This contributes to a better mixing of the components of the concrete mixture, primarily to improve the dispersion of the complex additive in the volume of the concrete mixture. The caprolactam oligomer used in this research work is an effective water-soluble wetting agent for the surface of particles of cement, sand, and crushed stone, which is very important for activating hydration and sorption processes during mixing of a concrete mixture. The increased wetting properties of the caprolactam oligomer are characterized by a wetting angle of 19.6 °.

Solubility Enhancement of Poorly Water-Soluble Antifungal Drug Acyclovir by Nanocrystal Formulation Approach

2018 ◽  
Vol 11 (2) ◽  
pp. 4036-4042
Author(s):  
Prakash Goudanavar ◽  
Ankit Acharya ◽  
Vinay C.H
Keyword(s):  
Chemical Interaction ◽  
Research Work ◽  
Antiviral Drug ◽  
In Vitro Release ◽  
Oral Route ◽  
Water Soluble ◽  
Precipitation Method ◽  
Dsc Studies ◽  
Ft Ir

Administration of an antiviral drug, acyclovir via the oral route leads to low and variable bioavailability (15-30%). Therefore, this research work was aimed to enhance bioavailability of acyclovir by nanocrystallization technique. The drug nanocrystals were prepared by anti-solvent precipitation method in which different stabilizers were used. The formed nanocrystals are subjected to biopharmaceutical characterization including solubility, particle size and in-vitro release. SEM studies showed nano-crystals were crystalline nature with sharp peaks. The formulated drug nanocrystals were found to be in the range of 600-900nm and formulations NC7 and NC8 showed marked improvement in dissolution velocity when compared to pure drug, thus providing greater bioavailability. FT-IR and DSC studies revealed the absence of any chemical interaction between drug and polymers used. 

Improved Dissolution Properties of Ketoconazole through Application of Liquisolid Techniques

2015 ◽  
Vol 8 (4) ◽  
pp. 3053-3059
Author(s):  
Sudarshan Singh ◽  
S S Shyale ◽  
H G Sandip
Keyword(s):  
Drug Release ◽  
Immediate Release ◽  
Water Soluble ◽  
Wet Granulation ◽  
Wetting Properties ◽  
Enhanced Dissolution ◽  
Water Soluble Drug ◽  
Drug Concentrations ◽  
Water Soluble Drugs ◽  
Liquisolid Compacts

In present investigation liquisolid compact technique is investigated as a tool for enhanced dissolution of poorly water-soluble drug Ketoconazole. The liquisolid tablets were formulated with liquid medications, namely Propylene Glycol (PG) drug concentrations, 60% w/w, 70% w/w and 80% w/w. Avicel pH102 was used as a carrier material, Aerosil 200 as a coating material and Sodium starch glycollate as a super-disintegrant. Quality control tests, such as uniformity of tablet weight, uniformity of drug content, tablet hardness, friability test, disintegration and dissolution tests were performed to evaluate prepared tablets. For further confirmation of results the liquisolid compacts were evaluated by XRD and FTIR studies to prove that, solubility of Ketoconazole has been increased by liquisolid compact technique. From the results obtained, it was be speculated that such systems exhibit enhanced drug release profiles due to increased wetting properties and surface of drug available for dissolution. As liquisolid compacts demonstrated significantly higher drug release rates, in PG as compared to directly compressible tablets and conventional wet granulation, we lead to conclusion that it could be a promising strategy in improving the dissolution of poor water soluble drugs and formulating immediate release solid dosage forms.  

Study of Rheological Properties of Modified Concrete Mixtures at Vibration

2019 ◽  
Vol 968 ◽  
pp. 96-106
Author(s):  
Oleksandr Pshinko ◽  
Olena Hromova ◽  
Dmytro Rudenko
Keyword(s):  
Mechanical Properties ◽  
Rheological Properties ◽  
Physical Nature ◽  
Concrete Mixture ◽  
Practical Significance ◽  
Vibration Displacement ◽  
Concrete Mixtures ◽  
Variable Quantity ◽  
Vibration Compaction ◽  
Mechanism Of Interaction

Study of rheological properties of concrete mixtures based on modified cement systems in order to determine process parameters. Methodology. To study structural-mechanical properties of modified concrete mixtures of different consistency at their horizontal vibrating displacement an oscillatory viscometer was designed. Results. The optimization of the process of vibration displacement of concrete mixtures with the specification of parameters of vibration impacts taking into account structural-mechanical properties of the mixture is performed. It has been established that the viscosity of the modified cement system of the concrete mixture is a variable quantity, which depends on the parameters of the vibration impacts. Scientific novelty. The mechanism of interaction of the modified concrete mixture with the form and the table vibrator during its vibration compaction is determined. On the basis of this, a model of concrete laying process control is proposed, that allows to predict the ability to form a dense concrete structure. Practical significance. Disclosed physical nature of the process of vibrating displacement of modified concrete mixtures using the principles of physical-chemical mechanics of concrete allows reasonably choose the best options for vibration impacts.

scholarly journals Enhancement of solubility and dissolution rate of poorly water soluble raloxifene using microwave induced fusion method

2013 ◽  
Vol 49 (3) ◽  
pp. 571-578 ◽  
Author(s):  
Payal Hasmukhlal Patil ◽  
Veena Sailendra Belgamwar ◽  
Pratibha Ramratan Patil ◽  
Sanjay Javerilal Surana
Keyword(s):  
Dissolution Rate ◽  
Hydroxypropyl Methylcellulose ◽  
Microwave Treatment ◽  
Water Soluble ◽  
Fusion Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Wetting Properties ◽  
Poorly Soluble ◽  
Poorly Water Soluble

The objective of the present work was to enhance the solubility and dissolution rate of the drug raloxifene HCl (RLX), which is poorly soluble in water. The solubility of RLX was observed to increase with increasing concentration of hydroxypropyl methylcellulose (HPMC E5 LV). The optimized ratio for preparing a solid dispersion (SD) of RLX with HPMC E5 LV using the microwave-induced fusion method was 1:5 w/w. Microwave energy was used to prepare SDs. HPMC E5 LV was used as a hydrophilic carrier to enhance the solubility and dissolution rate of RLX. After microwave treatment, the drug and hydrophilic polymer are fused together, and the drug is converted from the crystalline form into an amorphous form. This was confirmed through scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and powder X-ray diffraction (PXRD) studies. These results suggested that the microwave method is a simple and efficient method of preparing SDs. The solubility and dissolution rate of the SDs were increased significantly compared with pure RLX due to the surfactant and wetting properties of HPMC E5 LV and the formation of molecular dispersions of the drug in HPMC E5 LV. It was concluded that the solubility and dissolution rate of RLX are increased significantly when an SD of the drug is prepared using the microwave-induced fusion method.

scholarly journals DESIGN, DEVELOPMENT, AND CHARACTERIZATION OF OROMUCOSAL WAFER OF TRAMADOL HYDROCHLORIDE

2018 ◽  
Vol 11 (8) ◽  
pp. 116
Author(s):  
Rita N Wadetwar ◽  
Tejaswini Charde
Keyword(s):  
Drug Release ◽  
Biodegradable Polymer ◽  
Research Work ◽  
Water Soluble ◽  
Content Uniformity ◽  
Onset Of Action ◽  
Water Soluble Polymer ◽  
Surface Ph ◽  
Folding Endurance

Objective: The objective of the present work was the preparation of fast-dissolving film of tramadol HCl (TMH) using water-soluble polymer, to achieve faster onset of action, to improve patient compliance, ease of dosing, and bypass the first-pass metabolism. Methods: TMH oromucosal wafers were prepared using pullulan as natural, biodegradable polymer, and propylene glycol as plasticizer by solvent casting method. Formulation batches were prepared using 32 full-factorial designs. The prepared TMH oromucosal wafers were characterized for morphology, uniformity of weight, drug content, folding endurance, in vitro disintegration time (DT), % moisture content, surface pH, in vitro % drug release, ex vivo permeation studies, compatibility studies (differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray diffraction), and stability studies.Results: Optimized batch of mouth-dissolving film of TMH containing pullulan as polymer showed 98.67±0.11% drug release at 6 min. It showed better folding endurance 88 No. of folds, in vitro DT 5.11 s, surface pH 6.84±0.12 pH, thickness 0.17±0.11 mm, and percentage content uniformity 98.45±0.48%. Stability studies carried out for the best formulation FDF5 revealed that the formulation was stable.Conclusion: The results obtained in this research work clearly indicated a promising potential of fast-dissolving oral films using natural biodegradable polymer, pullulan which gave rapid drug delivery and rapid onset of action of centrally acting drug, TMH for patients suffering from pain.

scholarly journals MAIN PROBLEMS OF MANUFACTURING ASPHALT CONCRETE MIXTURES IN LITHUANIA/ASFALTBETONIO MIŠINIŲ GAMYBOS SVARBIAUSIOS PROBLEMOS LIETUVOJE

2000 ◽  
Vol 6 (1) ◽  
pp. 39-45
Author(s):  
Donatas Čygas
Keyword(s):  
Asphalt Concrete ◽  
High Speed ◽  
Statistical Data ◽  
Concrete Mixture ◽  
Cement Material ◽  
Asphalt Cement ◽  
Concrete Mixtures ◽  
Concrete Quality ◽  
Regressive Analysis ◽  
Speed Gradient

The article describes the main problems of manufacturing asphalt concrete mixtures at the factories under Ministry of Communication in the Republic of Lithuania. The Lithuanian Road Network is up to 21.122 km of state roads. 1.455 km of them are motorways, 3.415 km—national roads and 16.251 km—regional roads. Half of the state roads in Lithuania are paved with asphalt concrete. 98% of the motorways and 36% of the regional roads have asphalt pavement. Asphalt concrete pavement resistance to corrosion can be increased by improving asphalt concrete mixture production technology: ie by updating technological equipment, changing technological conditions and developing new methods of asphalt concrete mixture production. Therefore, the updating of asphalt concrete mixture production technologies is a very important factor for improving road operating properties and ensuring proper duration of asphalt concrete pavements. Here is the essence of the new separate successive technology: crushed stone and sand are mixed with bitumen in the main asphalt concrete mixer, the amount of bitumen being calculated according to the bitumen absorption in the materials. Then the asphalt cement material produced in a separate high-speed mixer is passed, and the whole mixture is remixed in the main mixer and supplied to the customer. Both separate consequent technologies differ from each other in the order of supplying asphalt cement material into the main mixing unit. Separate successive technology was theoretically grounded by the correlation between the technological thickness of bituminous film and the chemical-mineralogical composition and size of constituents, by the correlation between the particle size and their capability to compose aggregates, by the emergence of the oriented binding material coating on the technological bituminous film encoating mineral particles. Special attention is given to the manufacturing of asphalt cement material in a separate high-speed mixer (3 Table). It was theoretically grounded that mineral filler passing through the intensive shift zone between the paddle ends of the high-speed mixer and the walls of mixing chamber disintegrate and new active surfaces become visible. The molecular structure changes and free radicals appear. This intensive mixing guarantees high bitumen adsorption on the surface of mineral filler, which increases asphalt concrete resistance to corrosion and its durability, improves ecological environment in the asphalt concrete plant. In order to confirm the reliability of research results and explain correlative and regressive regularity, statistical data were processed applying statistical data processing programming system “STATGRAPHICS”. The linear regressive analysis for determining close relations of separate asphalt concrete quality indicators with speed gradient of asphalt cement material shift in a high-speed mixer was performed. Therefore, the possibility to change shift speed gradient from 3000 to 5000 1/s is provided in terms of reference for manufacturing asphalt concrete mixing plant. Correlation between separate asphalt concrete quality indicators and asphalt cement material shift speed gradient as well as bitumen amount in the asphalt cement material was determined by multi-dimensional regressive analysis of experimental data. The calculated correlation factor squared (R2) and F criteria indicate the adequacy and reliability of the multidimensional regression model.

scholarly journals FORMULATION AND EVALUATION OF ORMELOXIFENE FAST DISSOLVING TABLETS

2018 ◽  
Vol 6 (3) ◽  
pp. 17-31
Author(s):  
Abdul Hasan Sathali ◽  
Ramanathan M
Keyword(s):  
Solid Dispersion ◽  
Research Work ◽  
Solvent Evaporation ◽  
Water Soluble ◽  
Two Phase ◽  
Evaporation Technique ◽  
Co Precipitation ◽  
Phase Process

The objective of the present work was to enhancedissolution and solubility of slightly water soluble ormeloxifene hydrochloride and formulate fast dissolving tablets. The research work was two-phase process, the first phase was to enhance the solubility and dissolution of ormeloxifene. For this object drugwas processed with different solid dispersion techniques like kneading, co precipitation, melting and solvent evaporation technique with

Improving Safety when Extracting Water-soluble Ores by Optimizing the Parameters of the Backfill Mass

2021 ◽  
pp. 53-59
Author(s):  
M.M. Khayrutdinov ◽  
◽  
Ch.B. Kongar-Syuryun ◽  
A.M. Khayrutdinov ◽  
Yu.S. Tyulyaeva ◽  
...  
Keyword(s):  
Strain State ◽  
Raw Materials ◽  
Research Work ◽  
Integrated Approach ◽  
Water Soluble ◽  
Mining Operations ◽  
Stress Strain ◽  
Mining System ◽  
Stress Strain State ◽  
Geological Conditions

The results of the scientific and research work devoted to modeling the stress-strain state of the mining system of an underground mine using the finite element method in the FLAC3D software are presented in the article. The possibility of using room-and-pillar mining with backfill with the abandonment of chain pillars is justified. The results are presented concerning the research results of the quantitative assessment of the mass using the von Mises equation and Norton' power law of creep to estimate the contour stress. It becomes possible to determine the sequence of mining of the deposit area and the stage-by-stage filling of the stopes at the stage of mining design due to the high accuracy of modeling the stress-strain state of the mass near mining operations using FLAC3D software. The proposed approach is possible when evaluating the geotechnical state of the rock mass when using the mining systems with various methods of support of the mined-out area: natural; artificial; with the collapse of ores and enclosing rocks, as well as when calculating the combined method of deposit development. A differentiated approach to assessing the state of the mass is possible considering difficult mining and geological conditions, conditions of increased rock pressure, abundant water influx, increased fracturing of rocks by introducing additional conditions into the model depending on its geotechnical state. Variant of the comprehensive exploitation of mineral resources was proposed considering the total value of natural and man-made geo-resources of the area being mined. The possibility of rational use of the mined-out space with the use of various positive qualities of geo-resources at their manmade transformation is also considered. An assessment of the mineral and raw materials potential of the mined area is given with a proposal for the prospects of increasing the integrated approach of excavation, increasing the life of the mining enterprise and the complexity of developing this area.

DURABILITY PERFORMANCE AND DIMENSIONAL STABILITY OF POLYPROPYLENE FIBER REINFORCED CONCRETE

2018 ◽  
Vol 13 (2) ◽  
pp. 20-41 ◽  
Author(s):  
Ali Mardani-Aghabaglou ◽  
Süleyman Özen ◽  
Muhammet Gökhan Altun
Keyword(s):  
Reinforced Concrete ◽  
Dimensional Stability ◽  
Polypropylene Fiber ◽  
Pulse Velocity ◽  
Fiber Reinforced Concrete ◽  
Concrete Mixture ◽  
Fiber Reinforced ◽  
Concrete Mixtures ◽  
Durability Performance ◽  
Polypropylene Fiber Reinforced Concrete

In this study, the durability performance and dimensional stability of polypropylene fiber reinforced concrete mixture were investigated. For this purpose, two series of concrete mixtures, including a 0.45 water/cement ratio was prepared both in the absence and presence of fiber. A CEMI 42.5 R type portland cement and crushed limestone aggregate with a maximum particle size of 25 mm were used. In addition to the control mixture without fiber, three different concrete mixtures were prepared by adding polypropylene fiber as 0.4%, 0.8% and 1% of total volume into the mixture. The time-dependent fresh state properties, strength, ultrasonic pulse velocity, transport properties, drying shrinkage and freeze-thaw resistance of concrete mixtures, sodium sulfate attack and abrasion were investigated comparatively. Test results demonstrated that utilization of fiber affected the fresh properties of the concrete mixtures negatively. However, the 0.8% fiber-bearing mixture showed the highest performance in terms of durability and dimensional stability. Beyond this utilization ratio, the durability performance of the concrete mixture was negatively affected. The risk of nonhomogeneous dispersion of the fiber in the mixture was relatively high in the excess fiber-bearing mixture. Consequently, with the formation of flocculation in the mixture the void ratio of concrete mixture increased.

Compressive Strength of Concrete from Lightweight Bubbles Aggregate

2015 ◽  
Vol 754-755 ◽  
pp. 348-353 ◽  
Author(s):  
Norlia Mohamad Ibrahim ◽  
Leong Qi Wen ◽  
Mustaqqim Abdul Rahim ◽  
Khairul Nizar Ismail ◽  
Roshazita Che Amat ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Compressive Strength ◽  
Natural Resources ◽  
Concrete Structure ◽  
Concrete Mixture ◽  
New Materials ◽  
Concrete Mixtures ◽  
Compressive Strength Of Concrete

Compressive strength of concrete is the major mechanical properties of concrete that need to be focused on. Poor compressive strength will lead to low susceptibility of concrete structure towards designated actions. Many researches have been conducted to enhance the compressive strength of concrete by incorporating new materials in the concrete mixture. The dependencies towards natural resources can be reduced. Therefore, this paper presents the results of an experimental study concerning the incorporation of artificial lightweight bubbles aggregate (LBA) into cementations mixture in order to produce comparable compressive strength but at a lower densities. Three concrete mixtures containing various percentages of LBA, (10% - 50% of LBA) and one mixture used normal aggregate (NA) were prepared and characterized. The compressive strength of LBA in concrete was identified to be ranged between 39 MPa and 54 MPa. Meanwhile, the densities vary between 2000 kg/m3 to 2300 kg/m3.

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