The Characterization of Obsidian and its application to the Mediterranean Region

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.

2007 ◽  
Vol 1047 ◽  
Author(s):  
Andrew Shortland ◽  
Katherine Eremin ◽  
Susanna Kirk ◽  
James Armstrong

AbstractThe Hurrian city of Nuzi, in modern Iraq, was an important site during the Mesopotamian Bronze Age. Excavations in the late 20s and early 30s yielded a large and important assemblage of glass and other vitreous materials and smaller but significant assemblages of metals and ceramics. Although the vitreous materials have been widely studied in the past, the other assemblages have received little attention. However a recent study of some metal artifacts indicated the presence of brass and dirty copper rather than the expected bronze. This study was, however, limited to a few objects and the proportions of the different alloys was not investigated. Recent analytical studies on the glass beads have highlighted compositional differences between Egyptian and Mesopotamian glass and attempted to link these to the raw materials used. The lack of significant tin or zinc in glasses colored with copper is interesting given the presence of brass and the apparent scarcity of bronze in the copper alloys. The current study involves reassessment of the entire assemblage, concentrating initially on the vitreous materials, glazes and metals. Variations in preservation across the site and within individual buildings are currently being examined. Full characterization of the assemblages will allow relationships between different manufacturing technologies and the raw materials needed to be investigated.


Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2237 ◽  
Author(s):  
P. R. Sarika ◽  
Paul Nancarrow ◽  
Abdulrahman Khansaheb ◽  
Taleb Ibrahim

Phenol–formaldehyde (PF) resin continues to dominate the resin industry more than 100 years after its first synthesis. Its versatile properties such as thermal stability, chemical resistance, fire resistance, and dimensional stability make it a suitable material for a wide range of applications. PF resins have been used in the wood industry as adhesives, in paints and coatings, and in the aerospace, construction, and building industries as composites and foams. Currently, petroleum is the key source of raw materials used in manufacturing PF resin. However, increasing environmental pollution and fossil fuel depletion have driven industries to seek sustainable alternatives to petroleum based raw materials. Over the past decade, researchers have replaced phenol and formaldehyde with sustainable materials such as lignin, tannin, cardanol, hydroxymethylfurfural, and glyoxal to produce bio-based PF resin. Several synthesis modifications are currently under investigation towards improving the properties of bio-based phenolic resin. This review discusses recent developments in the synthesis of PF resins, particularly those created from sustainable raw material substitutes, and modifications applied to the synthetic route in order to improve the mechanical properties.


2021 ◽  
Vol 9 (10) ◽  
pp. 2007
Author(s):  
Rui Rocha ◽  
Manuela Vaz Velho ◽  
Joana Santos ◽  
Paulo Fernandes

Serra da Estrela PDO cheese is the oldest traditional cheese manufactured in Portugal. In this work, its microbiome as well as the main raw materials used in cheese production, raw ewes’ milk and thistle flowers (Cynara cardunculus L.), were characterized using next generation sequencing. Samples were accordingly retrieved from a local producer over two consecutive production campaigns and at different time periods within each campaign. The bacterial and fungi communities associated with each matrix were accessed through sequencing of V3−V4 and Internal Transcribed Spacer 2 regions of rRNA gene amplicons, respectively. A high microbial diversity was found associated to each matrix, differing significantly (p < 0.05) from each other. Over 500 taxa were identified in each analyzed matrix, ranging from dominant (relative abundance > 1%), sub-dominant (0.01−1%) and rare taxa (<0.01%). Specifically, in cheese, 30 taxa were present in all analyzed samples (core taxa), including species of Leuconostoc spp. and Lactococcus spp. for bacteria and Candida spp., Debaryomyces spp. and Yarrowia spp. for fungi, that were cumulatively the most prevalent genera in Serra da Estrela PDO cheese (average relative abundance ≥10%). Ultimately, this characterization study may contribute to a better understanding of the microbial dynamics of this traditional PDO product, namely the influence of raw materials on cheese microbiome, and could assist producers interested in preserving the identity, quality and safety of Serra da Estrela PDO cheese.


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.


2018 ◽  
Vol 22 (3) ◽  
pp. 318-341 ◽  
Author(s):  
Michael J Lynch ◽  
Paul B Stretesky ◽  
Michael A Long

During the development of green criminology, little attention has been paid to how Indigenous/Native Peoples (INP) are victimized by green crime and how they employ environmental activism to resist externally imposed ecological destruction. In the past decade, news services and environmental interest groups have reported on the killing of INP environmental activists who have resisted ecological destruction across the world. Here, we begin to develop a green criminological view of INP victimization and resistance to ecological destruction within the context of the global capitalist treadmill of production, while drawing upon concepts of colonization, imperialism, genocide and ecocide. Our analysis suggests that in the contemporary capitalist world system, expansion of the treadmill of production’s ecological withdrawal process (i.e. the withdrawal of raw materials used in production) not only accelerates ecological disorganization in developing/underdeveloped nations, but may be harmful in nations where INP are dependent on access to nature for survival.


1990 ◽  
Vol 1 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Hector Neff ◽  
Ronald L. Bishop ◽  
Dean E. Arnold

AbstractAn earlier study (Rice 1977, 1978a) purportedly found compositional similarity between raw materials used by modern potters in the northern Valley of Guatemala and Formative period whiteware ceramics from sites in the valley, particularly the major highland center of Kaminaljuyu. The compositional similarity suggested that Formative whiteware was manufactured in the northern valley, and this inference in turn underpinned a model of the development of ceramic craft specialization. Methodological weaknesses in the earlier study cast some doubt on its conclusions. More recent compositional analyses of Formative whiteware indicate that, while whiteware probably was made within the zone from which Kaminaljuyu drew its ceramics, it almost certainly was not made within the northern Valley of Guatemala. The present study highlights some important technical and methodological advances in compositional studies made over the past decade.


2018 ◽  
Vol 67 ◽  
pp. 03039
Author(s):  
Muhamad Sahlan ◽  
Charion Gibreth Hannes ◽  
Yanni Sudiyani ◽  
Heri Hermansyah ◽  
Anondho Wijanarko

One of the potential co-product of the manufacture of bioethanol made from oil palm empty fruit bunches are yeasts, which have antioxidant activity. Source of antioxidants can be obtained from vitamins and enzymes. In the characterization study of the antioxidant properties of yeast extract refers to a method performed by Xiong, by varying solvent and extraction time using hot water and ethanol 25%. From the variation of time and solvent extraction will be tested with the GSH content of alloxan method, to obtain the maximum concentration. The results show the isolation of amino acids with a hot solvent, at 15 minutes is better. These results are then carried out the characterization of amino acids with LCMS methods. An amino acid which has antioxidant activity is methionine, using the solvent water and tested methods of abortion LCMS and 3402.91 ppm ethanol with LCMS method implies 4137.002 ppm. Characterization of amino acids can then be used as a source of raw materials economic cosmetics worth selling.


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