Ancient Materials and Substitution Materials Used in Thai Historical Masonry Structure Preservation

The historical structures of Thailand are some of the most fascinating ancient sites in Asia.Their architectures reveal past cultures,traditions,knowledge,and expertise.Masonry materials are the major materials used to construct the historical structures in Thailand.One of the essential problem of Thai historical structure preservation is a shortage of engineering properties data for the structural stability assessment.Moreover,the in-depth engineering properties and the suitable substitution materials for Thai historical preservation are rarely found.Therefore,the engineering properties of the ancient masonry materials have to be explored together with the development of suitable substitute materials.This paper presents the physical and engineering properties of ancient materials and substitution materials for the preservation of Thailand’s historical structures.The ancient materials,including brick and mortar,are collected from historical places in the Bangkok and Ayutthaya Provinces.The physical and engineering properties of the masonry materials,such as the chemical composition,mineralogical composition,density,porosity,absorption,water vapor transmission,compressive strength,and modulus of elasticity,were evaluated in the laboratory.Fly ash was used as a pozzolanic material to partially replace the slaked lime to restore the historical mortar.The binder to sand ratio was controlled at 1:3 by weight.The slaked lime was substituted by fly ash at the rates of 10–30%by weight of binder.The engineering properties of the substitution mortars were also evaluated and compared with the ancient masonry materials.A masonry prism was also constructed to evaluate the compressive strength and the modulus of elasticity of the masonry structures.The physical and engineering properties of the ancient masonry materials obtained in this study can be included in a database for the preservation of Thailand’s historical masonry structures.The use of fly ash to partially replace the slaked lime could decrease the setting time and increase the compressive strength of historical repair mortar.The empirical equation obtained from this study could be used to predict the compressive strength of the masonry prisms of Thailand’s historical structures.

Materials Substitute Evaluation in the Production of Cement

The substitute of materials based on the materials of the value analysis is a valid path which can lower the cost of products. If the substitute of materials can be applied in Chinese enterprises producing cement, the technique can be advanced, and the remarkable economic performance can also be obtained.

A review of whole-process control of industrial volatile organic compounds in China

Volatile organic compounds(VOCs)play an important role in the formation of ground-level ozone and secondary organic aerosol(SOA),and they have been key issues in current air pollution prevention and control in China.Considerable attention has been paid to industrial activities due to their large and relatively complex VOCs emissions.The present research aims to provide a comprehensive review on whole-process control of industrial VOCs,which mainly includes source reduction,collection enhancement and end-pipe treatments.Lower VOCs materials including water-borne ones are the keys to source substitution in industries related to coating and solvent usage,leak detection and repair(LDAR)should be regarded as an efficient means of source reduction in refining,petrochemical and other chemical industries.Several types of VOCs collection methods such as gas-collecting hoods,airtight partitions and others are discussed,and airtight collection at negative pressure yields the best collection efficiency.Current end-pipe treatments like UV oxidation,low-temperature plasma,activated carbon adsorption,combustion,biodegradation,and adsorption-combustion are discussed in detail.Finally,several recommendations are made for future advanced treatment and policy development in industrial VOCs emission control.

Powder metallurgy with space holder for porous titanium implants:A review

One of the biggest challenges in the biocompatibility of implantable metals is the prevention of the stress shielding effect,which is related to the coupling of the bone-metal mechanical properties.This stress shielding phenomenon provokes bone resorption and the consequent adverse effects on prosthesis fixation.However,it can be inhibited by adapting the stiffness of the implant material.Since the use of titanium(Ti)porous structures is a great alternative not only to inhibit this effect but also to improve the osteointegration of orthopedic and dental implants,a brief description of the techniques used for their manufacturing and a review of the current commercialized implants produced from porous Ti assemblies are compiled in this work.As powder metallurgy(PM)with space holder(SH)is a powerful technology used to produce porous Ti structures,it is here discussed its potential for the fabrication of medical devices from the perspectives of both design and manufacture.The most important parameters of the technique such as the size and shape of the initial metallic particles,the SH and binder type of materials,the compaction pressure of the green form,and in the sintering stage,the temperature,atmosphere,and time are reviewed according to the bibliography reported.Furthermore,the importance of the porosity and its types together with the influence of the mentioned parameters in the final porosity and,consequently,in the ultimate mechanical properties of the structure are discussed.Finally,a few examples of the PM-SH application for the manufacturing of orthopedic implants are presented.