Application of Image Analysis for the Identification of Prehistoric Ceramic Production Technologies in the North Caucasus (Russia, Bronze/Iron Age)

The recent advances in microscopy and scanning techniques enabled the image analysis of archaeological objects in a high resolution. From the direct measurements in images, shapes and related parameters of the structural elements of interest can be derived. In this study, image analysis in 2D/3D is applied to archaeological ceramics, in order to obtain clues about the ceramic pastes, firing and shaping techniques. Images were acquired by the polarized light microscope, scanning electron microscopy (SEM) and 3D micro X-ray computed tomography (µ-CT) and segmented using Matlab. 70 ceramic sherds excavated at Ransyrt 1 (Middle-Late Bronze Age) and Kabardinka 2 (late Bronze–early Iron Age), located in in the North Caucasian mountains, Russia, were investigated. The size distribution, circularity and sphericity of sand grains in the ceramics show site specific difference as well as variations within a site. The sphericity, surface area, volume and Euler characteristic of pores show the existence of various pyrometamorphic states between the ceramics and within a ceramic. Using alignments of pores and grains, similar pottery shaping techniques are identified for both sites. These results show that the image analysis of archaeological ceramics can provide detailed information about the prehistoric ceramic production technologies with fast data availability

Thick-film materials for silicon photovoltaic cell manufacture

Thick film technology is applicable to three areas of silicon solar cell fabrication; metallization, junction formation, and coating for protection of screened ohmic contacts, particularly wrap around contacts, interconnection and environmental protection. Both material and process parameters were investigated. Printed ohmic contacts on n- and p-type silicon are very sensitive to the processing parameters of firing time, temperature, and atmosphere. Wrap around contacts are easily achieved by first printing and firing a dielectric over the edge and subsequently applying a low firing temperature conductor. Interconnection of cells into arrays can be achieved by printing and cofiring thick film metal pastes, soldering, or with heat curing conductive epoxies on low cost substrates. Printed (thick) film vitreous protection coatings do not yet offer sufficient optical uniformity and transparency for use on silicon. A sprayed, heat curable SiO2 based resin shows promise of providing both optical matching and environmental protection

Characteristics of grounding performance at Taman Bukit Perdana

Grounding system is one of the important part during installation of power systems. The function of grounding system is to enable protection to the power system in case of any current leakage or lightning strike. A grounding system will disconnect the circuit as soon as the fault current flows through the earth [1]. Every potential connection or equipment that may cause the current leakage must be grounded. In a simple way, it can be defined as the system to protect and stabilize the operation for human and equipment during fault conditions

Evidence of Resource Procurement and Manufacturing Techniques in Caddoan Ceramic Assemblages from the Sabine, Cypress, and Sulphur River Drainage Basins, Rusk and Titus Counties, Texas

Texas Utilities Services and Espey, Huston & Associates, Inc. have conducted ongoing archaeological investigations of cultural resources in Northeast Texas for the past 15 years. As a part of these studies, prehistoric Caddoan ceramic assemblages were recovered from 13 sites in three distinct drainage basins: three sites from the Sabine River drainage; three sites from the Cypress Creek drainage; and seven sites from the Sulphur River drainage. Recent research on the ceramic collections has emphasized variability in surface treatment, vessel form, and paste composition by means of a detailed attribute analysis and petrographic examination of a sample of the Caddoan sherds. This paper focuses on the paste composition of a sherd sample selected to undergo petrographic analysis. The sample contains representatives among the sherds of the major tempering agents identified during a macroscopic examination of the pastes. The initial goal of the analyses was establishment of a baseline for paste composition in the study areas. A detailed point count, and grain size measurements, allowed for the identification of constituents in a range of frequencies from among the sites located in each of the three drainage basins. Upon completion of the initial studies, the results of the analyses from the three studies were compared. This paper presents a discussion of preliminary patterns identified in Caddoan ceramic assemblages of resource procurement and manufacturing techniques observed among the site samples

Direct Extrusion Freeforming of Ceramic Pastes

Microextrusion freeforming of ceramic lattices from high solids ceramic pastes provides multi-scale hierarchical void structures with the advantages of low shrinkage stress and high sintered density. Alumina lattices were directly fabricated using 80-500 Pm diameter filaments. We report here on the implementation of design and fabrication of these scaffolds for band gap materials and micro fluidic devices.Mechanical Engineerin

Water Absorption Properties of Cement Pastes: Experimental and Modelling Inspections

An intermingled fractal units’ model is shown in order to simulate pore microstructures as pore fraction and pore size distribution. This model is aimed at predicting capillary water absorption coefficient and sorptivity values in cement pastes. The results obtained are in good agreement with the experimental ones. For validating this model, a comparison with other procedures has been shown. It is possible to establish that the newly proposed method matches better with the experimental results. That is probably due to the fact that pore size distribution has been considered as a whole. Moreover, even though the proposed model is based on fractal base units, it is able to simulate and predict different properties as well as nonfractal porous microstructure

Thermogravimetric Analysis of Indicators of the Paste Based on Sour Cream

For forming structural-mechanical properties of sour milk pastes and guaranteeing their stability at storage, it is promising to use non-fried buckwheat in their recipes that allows to raise the food value of products additionally. The aim of the researches was the study of features of the condition of moisture of sour milk pastes, based on sour cream with introducing non-fried buckwheat in the amount 5,0 % of the mixture mass. A sample with modified starch Е 1410 was taken as a control in the amount 1,3 %.The study of the moisture condition was realized by the thermogravimetric method using a derivatograph Q-1500D (Paulik-Erdey) (Hungry). It was established, that the content of adsorptive moisture of the sour milk paste was 34,0 %, whereas in the control – 34,5 %, that confirm the effectiveness of using non-fried buckwheat as a moisture-binding component. Such properties of non-fried buckwheat may be explained by the presence of starch compounds and easily accessible protein in its composition, able to hydration in the process of preparation of a component and to keeping moisture at further storage of a product

Coles Creek Culture and the Trans-Mississippi South

Certain Lower Mississippi Valley (LMV) traits, mostly Coles Creek ceramic traits, but also traits such as temple mounds and certain mortuary patterns, appear at Late Fourche Maline and Early Caddo sites in the Trans-Mississippi South, particularly at sites in the Red River Valley in northwest Louisiana and southwest Arkansas. Explaining how these traits got there and understanding their role in the development of Caddo culture is one of the basic problems in the archaeology of this area. The conventional explanation has long been that they represent a full scale intrusion of Coles Creek culture into the Trans-Mississippi South. Thus Michael Hoffman has created a Crenshaw phase of Coles Creek culture in the Great Bend region of the Red River Valley in southwest Arkansas, and Clarence H. Webb attributed the initial major occupation at the Mounds Plantation site in northwest Louisiana to Coles Creek peoples who laid out the plaza, possibly constructed Mound 2 as a quadrilateral temple substructure, and--at the opposite end of the plaza--established a burial area where Mound 5 sits

Development of durable “green” concrete exposed to deicing chemicals via synergistic use of locally available recycled materials and multi-scale modifiers

From the economic and social perspectives, the use of waste materials would not be attractive until their costs and quality can satisfy the construction requirements. In this study, a pure fly ash paste (PFAP) was developed in place of ordinary Portland cement paste (OPCP). This PFAP was prepared at room temperature and without direct alkali activation. The samples were prepared using only the as-received class C coal fly ash, water, and a very small amount of borax (Na2B4O7). On average, the PFAP featured 28-d compressive strength of about 36 MPa, and micro-nano hardness and elastic modulus 29% and 5%, higher than the OPCP, respectively. These mechanical and other properties of the PFAP make it a viable “green” construction binder suitable for a host of structural and non-structural applications. Advanced characterization of the raw material and PFAP pastes was employed to elucidate the hydration mechanisms of this “green” binder. The obtained knowledge sheds light on the role of class C CFA in the hydration process and may benefit the expanded use of various CFAs in cementitious materials