scholarly journals Geological Raw Materials from a Mesolithic Archaeological Site in NW Portugal

Proceedings ◽  
2019 ◽  
Vol 24 (1) ◽  
pp. 23
Author(s):  
Pedro Xavier ◽  
Carlos Alves ◽  
José Meireles

The present work concerns the study of geological raw materials obtained from an excavation site located in Serra da Cabreira (NW Portugal). The majority of the artifacts are made in quartz varieties (with minor occurrences of flint). Milky quartz is dominant, being similar to diverse occurrences of quartz veins in the immediate neighborhood. There are diverse other quartz varieties, indicating the possibility of locations farther away from the shelter. The study of geological raw materials can be seen as an important source of archaeological information, illustrating the evolution of past relationships between humans and geological resources, and also providing relevant information for the present and future, considering namely the extremely low environmental impact of the processing of raw materials.

Author(s):  
Pedro Xavier ◽  
José Meireles ◽  
Carlos Alves

In the 1990’s set of field surveys took place in the mountains of NW Portugal, leading to the discovery of the archaeological site named ‘Rock Shelter 1 of Cerdeira Valley’, situated in Cabreira Mountain (NW Portugal, max. alt. 1,262 m). The evidences recovered from the archaeological excavations established the shelter occupation between the end of the VI / beginning of the 5th millennium BC. Since 2017, within the context of an ongoing Phd project, the stone tool assemblage of the shelter is being analysed, in a double perspective. The first one relates to the complete techno-typological, identifying the objectives of the stone tool production and the second concerns with the classification and characterisation of different raw-materials exploited by the prehistoric communities.


1998 ◽  
Vol 25 (2) ◽  
pp. 283-291
Author(s):  
P.S.M. PHIRI ◽  
D.M. MOORE

Central Africa remained botanically unknown to the outside world up to the end of the eighteenth century. This paper provides a historical account of plant explorations in the Luangwa Valley. The first plant specimens were collected in 1897 and the last serious botanical explorations were made in 1993. During this period there have been 58 plant collectors in the Luangwa Valley with peak activity recorded in the 1960s. In 1989 1,348 species of vascular plants were described in the Luangwa Valley. More botanical collecting is needed with a view to finding new plant taxa, and also to provide a satisfactory basis for applied disciplines such as ecology, phytogeography, conservation and environmental impact assessment.


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.


Crystals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 15
Author(s):  
Cheng-An Tao ◽  
Jian-Fang Wang

Metal-organic frameworks (MOFs) have been used in adsorption, separation, catalysis, sensing, photo/electro/magnetics, and biomedical fields because of their unique periodic pore structure and excellent properties and have become a hot research topic in recent years. Ball milling is a method of small pollution, short time-consumption, and large-scale synthesis of MOFs. In recent years, many important advances have been made. In this paper, the influencing factors of MOFs synthesized by grinding were reviewed systematically from four aspects: auxiliary additives, metal sources, organic linkers, and reaction specific conditions (such as frequency, reaction time, and mass ratio of ball and raw materials). The prospect for the future development of the synthesis of MOFs by grinding was proposed.


2016 ◽  
Vol 881 ◽  
pp. 383-386 ◽  
Author(s):  
Raimundo J.S. Paranhos ◽  
Wilson Acchar ◽  
Vamberto Monteiro Silva

This study evaluated the potential use of Sugarcane Bagasse Ashes (SBA) as a flux, replacing phyllite for the production of enamelled porcelain tile. The raw materials of the standard mass components and the SBA residue were characterized by testing by XRF, XRD, AG, DTA and TGA. Test samples were fabricated, assembled in lots of 3 units and sintered at temperatures of 1150 ° C to 1210 ° C. The results of the physical properties, mechanical properties and SEM of the sintered samples, showed that the formulation, G4 - in which applied 10% of SBA replacing phyllite, sintering temperature 1210 ° C showed better performance as the previously mentioned properties due to the formation of mullite crystals, meeting the prerequisites of standards for enamelled porcelain tile, while reducing the environmental impact and the cost of production.


2014 ◽  
Vol 40 (2) ◽  
pp. 469-510 ◽  
Author(s):  
Khaled Shaalan

As more and more Arabic textual information becomes available through the Web in homes and businesses, via Internet and Intranet services, there is an urgent need for technologies and tools to process the relevant information. Named Entity Recognition (NER) is an Information Extraction task that has become an integral part of many other Natural Language Processing (NLP) tasks, such as Machine Translation and Information Retrieval. Arabic NER has begun to receive attention in recent years. The characteristics and peculiarities of Arabic, a member of the Semitic languages family, make dealing with NER a challenge. The performance of an Arabic NER component affects the overall performance of the NLP system in a positive manner. This article attempts to describe and detail the recent increase in interest and progress made in Arabic NER research. The importance of the NER task is demonstrated, the main characteristics of the Arabic language are highlighted, and the aspects of standardization in annotating named entities are illustrated. Moreover, the different Arabic linguistic resources are presented and the approaches used in Arabic NER field are explained. The features of common tools used in Arabic NER are described, and standard evaluation metrics are illustrated. In addition, a review of the state of the art of Arabic NER research is discussed. Finally, we present our conclusions. Throughout the presentation, illustrative examples are used for clarification.


2020 ◽  
Vol 26 (1) ◽  
pp. 82-93
Author(s):  
Reihaneh Radmanesh ◽  
◽  
Mohsen Nabi Meybodi ◽  
Vahid Ramezani ◽  
Maryam Akrami ◽  
...  

Aims: Any pharmaceutical product made in pharmacy, hospital or factory may be contaminated with microbes. This contamination can originate from raw materials or during production. Hence, it is important to study the physical and chemical properties and stability of compounded drugs. Methods & Materials: In this study, first a specific sample of prescribed medication was ordered from 63 pharmacies in Yazd, Iran. After collecting the samples, the amount of microbial contamination, viscosity and particle size distribution and their stability were investigated and their results were compared to the standard levels. Findings: Based on the results, 31.7% of the samples had discoloration and 23.8% showed creaming phenomenon. In terms of particle size distribution, 57.1% of the samples had a 20-40 μm particle size and 49.2% had a viscosity equal to 2500-3000 centipoise. Regarding stability, 12.6% of the samples underwnet phase change at 30-40°C. About of the amount of hydroquinone in samples, 35% had acceptable amount. In 23.8% of the samples, fungal infection was observed. Conclusion: Contrary to a popular belief that the compounded medicines produced in pharmacies have microbial contamination, the results of this study showed that the microbial contamination of these compounded medications is low.


Author(s):  
Dulce Maria Holanda Maciel ◽  
Luísa Córdova Wandscheer ◽  
Daniela Novelli

Thinking about innovations that reduce environmental impact and offer quality consumer goods is a way of proposing a future scenario governed by eco-efficiency values. Through an exploratory bibliographic and documentary research, which qualitatively analyses Kombucha authors and fermenters, this article seeks to identify the relationship between biomimetics and bacterial fabric production as an eco-efficient product in the fashion market chain. The general objective of this case study is to explain the fermentation process to encourage the search for raw materials inserted in the sustainability proposal.


2016 ◽  
Vol 3 (2) ◽  
Author(s):  
Mar Rey-Solé ◽  
Gemma Alías ◽  
Mireia Ache ◽  
Elicinia Fierro ◽  
Manel Edo ◽  
...  

Can Sadurní’s cave, located in Begues (NE Iberian Peninsula), in the Baix Llobregat region, is an archaeological site with a wide stratigraphic sequence covering from the Epipaleolithic hunter-gatherers societies at the beginning of the Holocene to Roman times. During the excavations of the last years a large number of different raw materials used for the manufacture of axes have been recovered.The present study is focused on the Neolithic sequence. 31 axes and adzes have been characterised petrographically with the aid of a binocular microscope and transmission microscope. A great variety of rocks constitute the raw materials of these stone tools, ranging from contact and regional metamorphic rocks to plutonic and porphyric igneous rocks. The formers are the most abundant (up to 78%) and include hornfels, spotted phyllites, marbles, quartzites, slates and phyllites. The igneous rocks consist of granodiorite, porphyry and aplites. Such a great assemblage of rocks matches in a geological context representative of a plutonic intrusion and its metamorphic contact aureole. Following that scenario we suggest that the most likely source area for all these materials occur at the Collserola hills, at 27 km far to the east from the cave, at the other side of the Llobregat River, where an Hercynian granodiorite and related igneous rocks intruding Ordovician metasedimentary materials are presented. 


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