Occurrence and ecological distribution of Heat Resistant Moulds Spores (HRMS) in raw materials used by food industry and thermal characterization of two Talaromyces isolates

2017 ◽  
Vol 242 ◽  
pp. 116-123 ◽  
Author(s):  
Roberta Tranquillini ◽  
Nicoletta Scaramuzza ◽  
Elettra Berni
Cerâmica ◽  
2012 ◽  
Vol 58 (347) ◽  
pp. 338-341 ◽  
Author(s):  
S. Meyvel ◽  
P. Sathya ◽  
G. Velraj

The archaeological pottery sherds excavated recently in Nedunkur, Tamilnadu, were analysed using Thermogravimetric (TG) and Differential Thermal analysis (DTA) with an objective of identifying the mineralogical characteristics of the raw materials used for their production. Besides, the thermal reactions associated over the linear temperature ramp from room temperature to 1200 °C in an inert atmosphere were also realized by TG-DTA. The characterization studies were able to indicate the conditions of firing process adopted and firing temperature attained by the artisans at the time of manufacture.


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3564
Author(s):  
Arnas Majumder ◽  
Laura Canale ◽  
Costantino Carlo Mastino ◽  
Antonio Pacitto ◽  
Andrea Frattolillo ◽  
...  

The building sector is known to have a significant environmental impact, considering that it is the largest contributor to global greenhouse gas emissions of around 36% and is also responsible for about 40% of global energy consumption. Of this, about 50% takes place during the building operational phase, while around 10–20% is consumed in materials manufacturing, transport and building construction, maintenance, and demolition. Increasing the necessity of reducing the environmental impact of buildings has led to enhancing not only the thermal performances of building materials, but also the environmental sustainability of their production chains and waste prevention. As a consequence, novel thermo-insulating building materials or products have been developed by using both locally produced natural and waste/recycled materials that are able to provide good thermal performances while also having a lower environmental impact. In this context, the aim of this work is to provide a detailed analysis for the thermal characterization of recycled materials for building insulation. To this end, the thermal behavior of different materials representing industrial residual or wastes collected or recycled using Sardinian zero-km locally available raw materials was investigated, namely: (1) plasters with recycled materials; (2) plasters with natural fibers; and (3) building insulation materials with natural fibers. Results indicate that the investigated materials were able to improve not only the energy performances but also the environmental comfort in both new and in existing buildings. In particular, plasters and mortars with recycled materials and with natural fibers showed, respectively, values of thermal conductivity (at 20 °C) lower than 0.475 and 0.272 W/(m⋅K), while that of building materials with natural fibers was always lower than 0.162 W/(m⋅K) with lower values for compounds with recycled materials (0.107 W/(m⋅K)). Further developments are underway to analyze the mechanical properties of these materials.


Clay Minerals ◽  
2018 ◽  
Vol 53 (3) ◽  
pp. 447-457
Author(s):  
A. Pountouenchi ◽  
D. Njoya ◽  
A. Njoya ◽  
D. Rabibisao ◽  
J.R. Mache ◽  
...  

ABSTRACTThree clayey materials named MY3, KK and KG originating from the Foumban region (west Cameroon) were analysed to determine their granulometry, plasticity, major-element chemistry and mineralogy. Dilatometric and ceramic behaviour were also investigated. Clays were shaped by uniaxial pressing in a steel mould. Shaped samples were heated at 1300, 1400 and 1500°C. The end products were characterized in terms of their density, porosity and compressive strength. Raw materials differ in terms of their mineralogical composition, grain-size distribution, Al2O3 content and the nature and abundance of impurities inducing specific thermal behaviour during dilatometric analysis and sintering tests. The final material properties may be related to the main features of the raw materials used.


2012 ◽  
Vol 727-728 ◽  
pp. 844-849 ◽  
Author(s):  
Tércio G. Machado ◽  
Uilame Umbelino Gomes ◽  
Flanelson M. Monteiro ◽  
Samara M. Valcacer ◽  
Gilson G. da Silva

The scheelite occurs mainly in northeastern Brazil, with highest abundance in the states of Rio Grande do Norte and Paraíba - Scheelite Seridó Province. Mining is considered an activity that provides a high environmental degradation due to the large amount of minerals and waste involved. Most mining companies have no technologies or processes that allow the recycling of mineral waste generated. The aim of this study is to evaluate the influence of different percentages of reject on the mechanical properties of scheelite and aesthetic (staining of the final product after firing) of the clay of the city of Boa Saúde - RN. The raw materials used were characterized by XRD, XRF and particle size analysis. Assay was performed by water absorption, linear retraction and bending tests on three points for the characterization of the final product. The raw materials used were from the city of Currais Novos-RN.


2010 ◽  
Vol 636-637 ◽  
pp. 1421-1427
Author(s):  
F. Parrés ◽  
J.E. Crespo ◽  
A. Nadal ◽  
A. Macias-Garcia ◽  
E.M. Cuerda-Correa

The importance of recovering and valorising the residues generated by industrialized societies is mainly due to the environmental impact that such residues may cause. In this connection, scrap tires constitute a major source of pollution. In the recent years large amounts of scrap tires have been recycled in order to recover the metals contained in this residue. Tires have also been grinded and the small particles produced have found different applications. In addition to metals and rubber particles, reinforcing fibers are also produced in the recycling process of scrap tires. As a previous step for the valorisation of this third constituent of waste tires, a characterization of such fibers is strongly recommended. Thermal analysis techniques make it possible to identify the fibers through the thermal transitions that may take place. Usually, such transitions result mainly in cotton and rayon. Furthermore, the combination of pyrolysis, gas chromatography and mass spectrometry techniques corroborates the identification of several compounds derived from the decomposition of the fibers as well as some materials used in the preparation of tires.


2013 ◽  
Vol 66 (1) ◽  
pp. 91-98 ◽  
Author(s):  
José Manuel Rivas Mercury ◽  
Domingos de Jesus Costa Pereira ◽  
Nazaré do Socorro Lemos Silva Vasconcelos ◽  
Aluísio Alves Cabral Jr. ◽  
Romulo Simões Angélica

This work involved the first-ever characterization of antique Portuguese ceramic wall tiles in the Historic Center of São Luis do Maranhão, Brazil. The tiles were characterized by optical microscopy, X-ray diffraction (XRD) and chemical analysis to identify the possible raw materials used in the fabrication process, as well as the firing temperature of these materials. The results indicate that the microstructure of these materials consists of pores of varying sizes with calcite incrustations and quartz grain sizes smaller than 500 µm distributed in a pinkish yellow matrix, which were identified by XRD as calcite, gehlenite, wollastonite, quartz, and amorphous mineral phases. Based on this information, it can be inferred that the original raw materials probably consisted of a mixture of kaolinitic clays (Al2O3·2SiO2·2H2O) rich in calcium carbonates and quartz, or mixtures of kaolinitic clays, quartz and calcite, which did not reach the pre-firing temperature of 950ºC.


1964 ◽  
Vol 30 ◽  
pp. 111-133 ◽  
Author(s):  
J. R. Cann ◽  
Colin Renfrew

Evidence of contact between cultural groups is of great importance to the study of prehistory. Although the development of absolute dating methods has decreased our dependence on the discovery of such contacts for chronology, they are essential material when the origin and spread of culture is being studied. In the past, cultural contacts have generally been demonstrated by typological similarities of artifacts, but unfortunately many typological comparisons are open to discussion, and it can be exceedingly difficult to be certain of direct contact by this means alone.The importance in this respect of the study of raw materials used in places far from their place of origin and presumably deliberately imported has long been realized. Recently more attention has been paid to the careful characterization of such materials; the detection, that is, of properties of the specimen under study which are characteristic of material from particular sources. By this means it is often possible to assign a source to a given specimen. The petrological identification of British neolithic stone axes is perhaps the most comprehensive archaeological characterization study yet undertaken. Demonstrations of trading links made by such methods, if based on a sure identification and a comprehensive survey of possible sources, are not open to the criticism and doubt which may be directed at typological similarities. The variety of techniques now available for the analysis and identification of materials makes this field a promising one for the archaeologist.


2014 ◽  
Vol 976 ◽  
pp. 148-153 ◽  
Author(s):  
Carlos Alberto León ◽  
Gabriel Rodríguez-Ortiz ◽  
E.A. Aguilar-Reyes ◽  
Makoto Nanko ◽  
M. Takeda

Copper based composites with 30, 40, 50 and 60 vol.% Al2O3 were fabricated by powder metallurgy and consolidated by pulsed electric current sintering (PECS). For the purpose of determining the advantage of using coated fillers, composite alumina particles with 18 vol.% copper were prepared by electroless copper plating. Coatings were continuous and homogeneous through alumina surface. Thus, composites consolidated by the modified process increased contact between the matrix and filler, which resulted in superior thermo-physical properties. Thermal conductivities of 210-99 and 227-114 W/mK were obtained for Cu/Al2O3 made by the admixture and the coated filler method, respectively. Such superiority is mainly attributed to the continuity in the matrix phase; the thermal conductivity values observed are similar to those shown by the traditional materials used in electronic packaging. The coefficient of thermal expansion was slight lower in composites fabricated by the coated filler method; values in the ranges of 14-11 and 13-10.5 μm/m°C were obtained for the admixture and the coated filler method, respectively.


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