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Rattanadecho P.,Rangsit University | Makul N.,Phranakhon Rajabhat University
Drying Technology | Year: 2016

Offering advantages of energy-saving rapid drying rates, short processing times, deep penetration of the microwave energy, instantaneous and precise electronic control, and clean heating processes, microwave-assisted drying (MWD) has become a popular method that is currently used for many materials and processes. This article presents a systematic and comprehensive review of experimental and theoretical studies regarding the kinetic mechanisms of MWD. Factors affecting, methods for measuring, and applications of the dielectric property are discussed. From the experimental perspective, laboratory- and commercial-scale MWD systems are elaborated, including the equipment used and the stability, safety, and regulation of MWD systems. Theoretical investigations of thermal and nonthermal equilibrium models and moving-load computational models are discussed. Finally, some future trends in the research and development of MWD systems are suggested. © 2016, Copyright © Taylor & Francis Group, LLC.


Makul N.,Phranakhon Rajabhat University | Rattanadecho P.,Rangsit University | Agrawal D.K.,Pennsylvania State University
Renewable and Sustainable Energy Reviews | Year: 2014

Microwave heating is a highly efficient technique for various thermal processes. Advantages of microwave heating compared to conventional processing methods include energy-saving rapid heating rates and short processing times, deep penetration of the microwave energy (which allows heat to be generated efficiently without directly contacting the work-piece), instantaneous and precise electronic control, clean heating processes, and no generation of secondary waste. Microwave energy processes for heating, drying, and curing have been developed for numerous laboratory-scale investigations and, in some cases, have been commercialized. Microwave energy use should theoretically be advantageous in the processing of cement and concrete materials (e.g., hydraulic Portland cement, aggregate, and water). These materials exhibit excellent dielectric properties and, therefore, should be able to absorb microwave energy very efficiently and instantaneously convert it into heat. This paper provides a comprehensive review of the use of microwave energy to process cement and concrete materials, as well as a critical evaluation of currently utilized microwave heating mechanisms and high-performance microwave systems. The current status of microwave applications and future research and development trends are also discussed, including such thermal processing methods as the high-temperature sintering of cement materials, the accelerated curing of precast concrete products, as well as the drilling and cleaning of decontaminated concrete surfaces by the built-up internal pressure. The results of this review indicate that microwave heating is directly associated with dielectric loss by the cement and concrete. Microwave processing can be used to improve clinkering and to reduce the clinkering temperature by about 100 °C. Considerations when constructing mathematical models of microwave heating for cement and concrete should include the influences of heat and mass transfer during microwave curing on the temperature difference in the concrete, the degree of uniformity of the internal structure, and the ultimate performance of the product. Future studies of microwave energy in cement and concrete applications might include investigations of adaptive (time-dependent) dielectric properties, coupling chemical reactions in the presence of microwave energy, the design and construction of suitable microwave systems, and the prediction of related phenomena (e.g., thermal runaway, as a highly regulated safety issue). © 2014 Elsevier Ltd.


Ahmed I.,University of Maryland University College | Jangsawang W.,University of Maryland University College | Jangsawang W.,Phranakhon Rajabhat University | Gupta A.K.,University of Maryland University College
Applied Energy | Year: 2012

Mangrove is a biomass material that grows in wetland sea waters and is often used to produce charcoal due to its unique characteristics of long and sustained burning and negligible residue. High temperature pyrolysis has been conducted for mangrove biomass in a laboratory scale semi-batch reactor. The effect of reactor temperature on syngas yield and syngas characteristics has been investigated. Reactor temperature was varied from 600 to 900 °C in 100 °C intervals. The increase in reactor temperature resulted in increased syngas yield, hydrogen yield and energy yield. Evolutionary behavior of the syngas characteristics has also been investigated. The increase in reactor temperature increased the peak value of syngas flow rate, hydrogen flow rate and output power. The increase in reactor temperature decreased the time duration of pyrolysis. Cumulative yield of syngas, hydrogen and energy was calculated based on the time dependent relationship. Higher reactor temperatures shortened the time duration required for 99% release of syngas, hydrogen and energy. For example, time duration required for 99% yield of hydrogen was approximately 73. min at 600 °C and only about 26. min at 900 °C. Required time duration for 99% yield of energy was ∼62. min at 600 °C and ∼15. min at 900 °C. The gasification of the same material at 900 °C has been carried out to determine the role of gasifying agent on the fate of material and resulting syngas properties. The results showed gasification yielded more syngas, hydrogen and energy than that obtained from pyrolysis. © 2011 Elsevier Ltd.


Sua-Iam G.,Phranakhon Rajabhat University | Makul N.,Phranakhon Rajabhat University
Journal of Cleaner Production | Year: 2013

Bagasse ash is an abundantly available combustion by-product in the sugarcane industry. We examined the effect of adding limestone powder to self-compacting concrete mixtures in which large amounts of bagasse ash were employed as a fine aggregate replacement. A Type 1 Portland cement content of 550 kg/m3 was maintained in all of the mixtures. The fine aggregate was replaced with 10, 20, 40, 60, 80, or 100% bagasse ash and limestone powder by volume. Mixtures were designed to yield a slump flow diameter of 70 ± 2.5 cm. The workability (slump flow, T50cm slump flow time, V-funnel flow time, and J-ring flow) and hardened properties (ultrasonic pulse velocity and compressive strength) of each mixture were measured, and blocking assessments were performed. The volumetric percentage replacement of 20% limestone powder in fine aggregate incorporating 20% bagasse ash effectively enhanced the workability and hardened properties of self-compacting concrete.


Sua-Iam G.,University of Management and Technology | Makul N.,Phranakhon Rajabhat University
Advanced Materials Research | Year: 2012

This paper presents the properties of self-compacting concrete (SCC) incorporating residual rice husk ash (RHA) from thermal power plant. It was ground by a mechanical grinding method using ceramic ball mill until having the volume moment mean of 24.32 μm. The cementitious materials (Portland cement Type 1, OPC, and RHA) for all SCC mixtures content was kept constantly at 550 kg/m3. RHA was partially replaced in Portland cement (0, 10, 20 and 40%wt.) in producing SCC with the controlled water/cementitious (W/C) ratios of 0.28 and 0.33 by weight. Tests of fresh state properties were investigated including slump flow, V-funnel flowing time, unit weight. Further, compressive strength and ultrasonic pulse velocity were tested. It is concluded that an optimum RHA replacement level of 20%wt. has the best performance of the SCC with different levels of RHA.


In this study, cementitious materials (here defined as a high-performance cement paste produced by mixing Type 1 Portland cement with an effective amount of water) were manufactured in accelerated conditions using microwave-assisted low-pressure processing (i.e., accelerated curing). Based on the concept that the hydration reaction of cementitious materials comprises three main periods - a dormant period, an acceleration period, and a deceleration period - process parameters were determined for the most effective period (acceleration) for producing paste via microwave processing. The time-dependent dielectric characteristics of the cementitious paste and the water-cement ratio by mass influenced the temperature, i.e., caused it to increase, and the properties of the microwave-cured paste. The results show that the use of microwave-assisted low-pressure processing improved the paste's mechanical properties. Specifically, microwave energy can accelerate compressive strength development 15 min after the completion of microwave-assisted low-pressure curing. With a delay time of 60 min, microwave energy can process the paste almost a day faster than water curing, which is the standard method for curing paste. The use of microwave energy, therefore, can significantly reduce the required energy and production time in the manufacture of high-performance paste. © 2015 Elsevier Ltd. All rights reserved.


Sua-Iam G.,Phranakhon Rajabhat University | Makul N.,Phranakhon Rajabhat University
Journal of Cleaner Production | Year: 2014

This paper describes a study undertaken to explore the use of a high volume of lignite coal fly ash (FA) as a replacement for Type I Portland cement (OPC) and a high volume of rice husk ash (RHA) as a replacement for fine aggregate in the production of self-consolidating concrete (SCC). OPC was partially replaced with 0%, 20%, 40%, and 60% FA by volume, and fine aggregate was replaced with 0%, 25%, 50%, 75%, and 100% RHA by volume. Mixtures were designed based on a slump flow diameter of 70 ± 2.5 cm. The workability properties (i.e. slump flow, T50 cm slump flow time, V-funnel flow time, and J-ring flow) and hardened properties (i.e. compressive strength and ultrasonic pulse velocity) of SCC were determined, and a blocking assessment was performed. Increasing the FA or RHA content beyond a certain level reduced the compressive strength and increased the water requirement of the SCC mixture. However, up to 60% FA could be used to produce SCC with a compressive strength of 40-50 MPa. In addition, RHA could comprise up to 25% of the SCC, which is an acceptable value of compressive strength according to the Building Code Requirements. Moreover, partial replacement of OPC by FA and fine aggregate by RHA can result in substantial cost savings and alleviate environmental problems. © 2014 Elsevier Ltd. All rights reserved.


Khucharoenphaisan K.,Phranakhon Rajabhat University | Sripairoj N.,Phranakhon Rajabhat University | Sinma K.,Phranakhon Rajabhat University
Asian Journal of Animal and Veterinary Advances | Year: 2012

Actinomycetes are a group of prokaryotic organisms belonging to Gram-positive bacteria and play an important ecological role in recycling substances in the nature. The objective of this study was to isolate and identify actinomycetes from termite's gut against human pathogen. Total isolates were examined for antimicrobial activity and selected isolate was identified using morphological characters and molecular technique. The results showed that eighty-three strains of actinomycetes were isolated from guts of Termes sp. Among these, 66, 67, 7, 9 and 3 isolated strains were active against the tested pathogenic microorganism of Bacillus cereus, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Candida utilis, respectively. Furthermore, some isolate of actinomycetes was able to inhibit both Gram-positive and Gram-negative pathogen. The isolated actinomycetes strain FSPNRU 102 having broad spectrum of inhibition was selected. The morphological character of this strain showed aerial mycelium with longitudinal spirales-type spore chain and light black soluble pigment. The aerial spore color varied from white to gray. Moreover, this strain contained LL-diaminopimelic acid of the peptidoglycan in the whole-cell hydrolysate of chemotaxonomical characteristic. These results assigned strain FSPNRU 102 to genus Streptomyces. Based on its 16S rDNA sequence and phylogenetic tree analysis, this new isolate belong to the Streptomyces niveoruber. © 2012 Academic Journals Inc.


Sua-Iam G.,Phranakhon Rajabhat University | Makul N.,Phranakhon Rajabhat University
Construction and Building Materials | Year: 2013

Alumina is a common by-product of industrial grit blasting operations. While alumina itself is relatively harmless, the grit blasting waste is regarded as hazardous when contaminated with heavy metals. The concrete industry has initiated the use of solid waste additives in order to address environmental problems. We studied the feasibility of using alumina waste (AW) as a partial replacement for the fine aggregate in self-compacting concrete (SCC). The mixtures were designed to produce a controlled slump flow diameter. The fine aggregate was replaced with up to 100% AW by weight. The rheological and mechanical properties of the SCC mixtures were evaluated based on slump flow, J-ring flow, blocking assessment, V-funnel, air content, compressive strength, and ultrasonic pulse velocity measurements. The filling and passing ability of the fresh concrete decreased in proportion to the alumina content. Mixtures containing up to 75% AW possessed average compressive strengths of 20.9 MPa at 3 days and 45.9 MPa at 28 days. © 2013 Elsevier Ltd. All rights reserved.


Sua-Iam G.,Phranakhon Rajabhat University | Makul N.,Phranakhon Rajabhat University
Construction and Building Materials | Year: 2013

Self-compacting concrete (SCC) is a relatively recent development in the construction industry. It flows under its own weight while remaining homogeneous in composition. We examined the feasibility of using limestone powder (LS) as a modifying agent in self-compacting concrete in which a portion of the fine aggregate was replaced with untreated rice husk ash (RHA). The mixtures were designed to produce a controlled slump flow. The Portland cement content was 550 kg/m3 for all of the mixtures. The fine aggregate was replaced with up to 100% RHA and LS by volume. The T50 slump flow, J-ring flow, blocking assessment, V-funnel, air density, and compressive strength of the SCC mixtures were tested. The fresh properties of the RHA-containing mixtures were improved in mixtures containing less than 60 vol.% RHA. SCCs containing LS exhibited superior hardened properties, and the fresh and hardened properties of SCCs made using RHA were substantially improved when combined with LS. Limestone powder has the potential to improve self-compacting concrete mixtures in which untreated RHA is used as a partial fine aggregate replacement. © 2012 Elsevier Ltd. All rights reserved.

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