scholarly journals Microwave Technology Using Low Energy Concentrated Beam for Processing of Solid Waste Materials from Rapana thomasiana Seashells

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6780
Author(s):  
Sorin Vasile Savu ◽  
Daniela Tarnita ◽  
Gabriel Constantin Benga ◽  
Ilie Dumitru ◽  
Iulian Stefan ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Energy Efficiency ◽  
Solid Waste ◽  
Microwave Heating ◽  
Microwave Plasma ◽  
Arc Discharge ◽  
Advanced Technology ◽  
Resistance Heating ◽  
Plasma Arc Discharge ◽  
The Stability

The solid waste of Rapana thomasiana seashells both from domestic activities and natural waste on seashore can be used to obtain viable products for medical applications. However, conventional technologies applied for sintering the materials require massive energy consumption due to the resistance heating. Microwave heating represents an advanced technology for sintering, but the stability of the process, in terms of thermal runaway and microwave plasma arc discharge, jeopardizes the quality of the sintered products. This paper aims to present the results of research focused on viable heating technology and the mechanical properties of the final products. A comparative analysis, in terms of energy efficiency vs. mechanical properties, has been performed for three different heating technologies: direct microwave heating, hybrid microwave heating and resistance heating. The results obtained concluded that the hybrid microwave heating led to final products from Rapana thomasiana solid waste with similar mechanical properties compared with resistance heating. In terms of energy efficiency, the hybrid microwave heating was 20 times better than resistance heating.

Influence of the Shape of Composites Materials on the Stability of Microwave Heating Processes

2021 ◽  
Vol 42 ◽  
pp. 36-41
Author(s):  
Robert Cristian Marin ◽  
Iulian Ştefan ◽  
Mihaela Cristina Predescu ◽  
Sorin Vasile Savu
Keyword(s):  
Thermal Stability ◽  
Microwave Heating ◽  
Microwave Plasma ◽  
Experimental Program ◽  
Combustion Engines ◽  
Nitrogen Oxide Emissions ◽  
Fast Heating ◽  
Composites Materials ◽  
Different Shapes ◽  
The Stability

This paper aims to present preliminary researches on the influence of the shape and dimensions of composites materials on the stability of microwave heating. The research was focused on cordierite composite material, which is used as ceramic substrate in selective catalytic reaction for reduction of nitrogen oxide emissions from combustion engines. For experimental program were used different shapes for cordierite material, such as cubic, cylindrical, sphere and rectangular. Based on previous researches where it was demonstrated that an injected microwave power between 600 W and 1200 W, the samples were heated in order to establish which shape is more suitable for fast heating, thermal stability in terms of thermal runaway as well as for avoiding the unwanted microwave plasma initiation.

Experimental study on mechanical properties of anti-seepage slurry in landfill

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840065 ◽  
Author(s):  
Guozhong Dai ◽  
Yanmin Sheng ◽  
Shujin Li ◽  
Yaxing Zhang
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Fly Ash ◽  
Municipal Solid Waste ◽  
Solid Waste ◽  
Cement Paste ◽  
Crucial Role ◽  
The Stability ◽  
Water Absorbability ◽  
Skeleton Structure

Municipal solid waste has increased with the development of urbanization which sets a high request to the stability of landfill. The strength of anti-seepage slurry plays a crucial role in the stabilization of landfill. The ratio of each component was changed to test the slurry strength of different ages. Results show that the slurry strength increased with the raise of cement paste because the strength was mainly determined by the skeleton structure. In contrast, the excessive bentonite reduced the strength of slurry, for the excessive bentonite may package the skeleton structure of cement-fly ash instead of filling in. The dosage of Na2CO3 and PVA increasing to 3.0 g also reduced the strength of the slurry, because the water absorbability and expansibility of bentonite were inhibited and the effect of reinforcement on cement-fly ash structure was weaken.

scholarly journals The Stability Evaluations of Municipal Landfill in Malaysia for Future Land Use

2013 ◽  
Vol 864-867 ◽  
pp. 1128-1131
Author(s):  
Nik Daud Nik Norsyahariati ◽  
Azman Nurul Ayunie ◽  
Ibrahim Siti Aisyah ◽  
Ahsan Amimul
Keyword(s):  
Mechanical Properties ◽  
Solid Waste ◽  
Chemical Properties ◽  
Landfill Site ◽  
Physical And Chemical Properties ◽  
Waste Composition ◽  
The Stability ◽  
Physical And Chemical ◽  
Settlement Behaviour ◽  
And Chemical Properties

The research is about the investigation of the effects of landfill stability with relation to the solid waste composition in landfill site located in Selangor, Malaysia. The stability of a landfill relies on the shear strength of its elements and their settlement behaviour. Most of the landfill is made up of Municipal Solid Waste (MSW), so the overall stability of the landfill slopes is governed by the physical, chemical and mechanical properties of the MSW. The main objective of this research is to determine the relationship between solid waste composition and their mechanical properties in order to analyse the site stability. The workplan begin with the desk study and proceed with physical and chemical properties test followed by the implementation of details laboratory works for testing the mechanicals parameters. A landfill site has been selected and four samples location differred by age were chosen in order to have a clear view of the overall solid waste composition and the geotechnical condition of selected landfill site. Basic physical and chemical properties of MSW were carried out such as moisture content, specific gravity and organic content. In terms of mechanical properties; shear strength and settlement behaviour were investigated. At the end of this study, several salient points have been concluded with respected to the solid waste composition and the site stability analysis.

An analysis of the transport properties and mechanical stability of rapidly solidified Al-Sb alloy

2015 ◽  
Vol 10 (2) ◽  
pp. 2663-2681
Author(s):  
Rizk El- Sayed ◽  
Mustafa Kamal ◽  
Abu-Bakr El-Bediwi ◽  
Qutaiba Rasheed Solaiman
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Melt Spinning ◽  
Elastic Moduli ◽  
Mechanical Stability ◽  
Microstructural Analysis ◽  
Alloy System ◽  
Antimony Content ◽  
The Stability ◽  
Rapidly Solidified

The structure of a series of AlSb alloys prepared by melt spinning have been studied in the as melt–spun ribbons  as a function of antimony content .The stability  of these structures has  been  related to that of the transport and mechanical properties of the alloy ribbons. Microstructural analysis was performed and it was found that only Al and AlSb phases formed for different composition.  The electrical, thermal and the stability of the mechanical properties are related indirectly through the influence of the antimony content. The results are interpreted in terms of the phase change occurring to alloy system. Electrical resistivity, thermal conductivity, elastic moduli and the values of microhardness are found to be more sensitive than the internal friction to the phase changes. 

scholarly journals Performance Evaluation of Heading-and-Winning Machines in the Conditions of Potash Mines

2021 ◽  
Vol 11 (8) ◽  
pp. 3444
Author(s):  
Sergey A. Lavrenko ◽  
Dmitriy I. Shishlyannikov
Keyword(s):  
Energy Efficiency ◽  
Experimental Studies ◽  
Efficiency Coefficient ◽  
Mechanized Method ◽  
Methodological Approaches ◽  
The Stability ◽  
Technical Solutions ◽  
Potash Mine ◽  
Complex Indicators ◽  
Potassium Magnesium

The authors focus on the process of potash ore production by a mechanized method. They show that currently there are no approved procedures for assessing the performance of heading-and-winning machines operating in the conditions of potash mines. This causes difficulties in determining the field of application of heading-and-winning machines, complicates the search for implicit technical solutions for the modernisation of existing models of mining units, prohibits real-time monitoring of the stability of stope-based technological processes and makes it difficult to assess the performance of the services concerning mining enterprises. The work represents an aggregate assessment of the performance of heading-and-winning machines for potash mines by determining complex indicators describing the technological and technical levels of organising the work in stopes. Such indicators are the coefficients of productivity and energy efficiency, respectively. Experimental studies have been carried out in the conditions of the potash mine of the Verkhnekamskoye potassium-magnesium salt deposit to assess the performance of the latest and most productive Ural-20R heading-and-winning machines manufactured in Russia. Using the above methodological approaches, this paper shows that the unsatisfactory technological performance of the studied machine is due to the low productivity of the mine district transport. The average productivity coefficient was 0.29. At the same time, high values of the energy efficiency coefficient show that the productivity of the machine is on par with design conditions.

Effect of the surface chemistry on the stability and mechanical properties of the Zirconia-Hydroxyapatite bioceramic

2021 ◽  
Vol 23 ◽  
pp. 100980
Author(s):  
M. Es-saddik ◽  
S. Laasri ◽  
M. Taha ◽  
A. Laghzizil ◽  
A. Guidara ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Surface Chemistry ◽  
The Stability

scholarly journals Studies on the Volumetric Stability and Mechanical Properties of Cement-Fly-Ash-Stabilized Steel Slag

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 495
Author(s):  
Mingkai Zhou ◽  
Xu Cheng ◽  
Xiao Chen
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Steel Slag ◽  
Critical Issue ◽  
Expansion Behavior ◽  
Strength Tests ◽  
Road Materials ◽  
Base Course ◽  
The Stability ◽  
Aggregate Base

The stability of steel-slag road materials remains a critical issue in their utilization as an aggregate base course. In this pursuit, the present study was envisaged to investigate the effects of fly ash on the mechanical properties and expansion behavior of cement-fly-ash-stabilized steel slag. Strength tests and expansion tests of the cement-fly-ash-stabilized steel slag with varying additions of fly ash were carried out. The results indicate that the cement-fly-ash-stabilized steel slag exhibited good mechanical properties. The expansion rate and the number of bulges of the stabilized material reduced with an increase in the addition. When the addition of fly ash was 30–60%, the stabilized material was not damaged due to expansion. Furthermore, the results of X-CT, XRD and SEM-EDS show that fly ash reacted with the expansive component of the steel slag. In addition, the macro structure of the stabilized material was found to be changed by an increase in the concentration of the fly ash, in order to improve the volumetric stability. Our study shows that the cement-fly-ash-stabilized steel slag exhibits good mechanical properties and volumetric stability with reasonable additions of fly ash.

Preparation of WC-TiC-Ni3Al-CaF2 functionally graded self-lubricating tool material by microwave sintering and its cutting performance

2020 ◽  
Vol 39 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Siwen Tang ◽  
Rui Wang ◽  
Pengfei Liu ◽  
Qiulin Niu ◽  
Guoqing Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Microwave Heating ◽  
Cutting Performance ◽  
Conventional Heating ◽  
Hard Alloys ◽  
Dry Cutting ◽  
Temperature Oxidation ◽  
Lubricating Material ◽  
Heating Technology

AbstractWith the concern of the environment, green dry cutting technology is getting more and more attention and self-lubricating tool technology plays an important role in dry cutting. Due to the demand for high temperature performance of tools during dry cutting process, cemented carbide with Ni3Al as the binder phase has received extensive attention due to its excellent high temperature strength and high temperature oxidation resistance. In this paper, WC-TiC-Ni3Al-CaF2 graded self-lubricating material and tools were prepared by microwave heating method, and its microstructure, mechanical properties and cutting performance were studied. Results show that gradient self-lubricating material can be quickly prepared by microwave heating technology, and the strength is equivalent to that of conventional heating technology. CaF2 not only plays a role in self-lubrication, but also refines the grain of the material. A reasonable gradient design can improve the mechanical properties of the material. When the gradient distribution exponent is n1 = 2, the material has high mechanical properties. Cutting experiments show that the WC-TiC-Ni3Al-CaF2 functional gradient self-lubricating tool has better cutting performance than the homogeneous WC-TiC-Ni3Al hard alloys.

scholarly journals Utilization of Solid Waste from Brick Industry and Hydrated Lime in Self-Compacting Cement Pastes

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1109
Author(s):  
Mati Ullah Shah ◽  
Muhammad Usman ◽  
Muhammad Usman Hanif ◽  
Iqra Naseem ◽  
Sara Farooq
Keyword(s):  
Mechanical Properties ◽  
Solid Waste ◽  
Manufacturing Industry ◽  
Setting Time ◽  
Hydrated Lime ◽  
Pozzolanic Reaction ◽  
Early Age ◽  
Cement Pastes ◽  
Brick Powder ◽  
High Degree

The huge amount of solid waste from the brick manufacturing industry can be used as a cement replacement. However, replacement exceeding 10% causes a reduction in strength due to the slowing of the pozzolanic reaction. Therefore, in this study, the pozzolanic potential of brick waste is enhanced using ultrafine brick powder with hydrated lime (HL). A total of six self-compacting paste mixes were studied. HL 2.5% by weight of binder was added in two formulations: 10% and 20% of waste burnt brick powder (WBBP), to activate the pozzolanic reaction. An increase in the water demand and setting time was observed by increasing the replacement percentage of WBBP. It was found that the mechanical properties of mixes containing 5% and 10% WBBP performed better than the control mix, while the mechanical properties of the mixes containing 20% WBBP were found to be almost equal to the control mix at 90 days. The addition of HL enhanced the early-age strength. Furthermore, WBBP formulations endorsed improvements in both durability and rheological properties, complemented by reduced early-age shrinkage. Overall, it was found that brick waste in ultrafine size has a very high degree of pozzolanic potential and can be effectively utilized as a supplementary cementitious material.

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