Eleven ancient Chinese ceramics from the early Bronze Age Qijia culture (c. 2200 – 1600 BCE) in the collection of the Harvard Art Museums were the subject of an interdisciplinary research project to explore questions about manufacturing techniques, specifically details of formation and decoration. While the Qijia culture, centered in the Gansu and Qinghai provinces of northwest China, is historically important as one of the earliest metalworking cultures of China and as a center of intercultural communication between China and central Asia, detailed scholarship about the culture is still emerging. Qijia ceramics have been categorized by typology, but little has been done regarding methods of manufacture. This study used visual examination and digital X-radiography to investigate ceramic production, especially the use of a wheel. In addition, the ceramic paste, including natural inclusions and temper, was examined. While film radiography has often been used to study ceramics, digital radiography presented new capabilities as well as challenges. Experimentation through the making of test vessels and tiles at the Harvard Ceramics Program provided additional insights into Qijia ceramics’ manufacture and surface decoration techniques, often described as cord-impressed.

Natural cane reeds (Latin name Arundo Donax L and here termed ADL) have been used on woodwind instruments for centuries with little change. The reed acts as a mechanical valve controlling the energy input into the musical instrument and it is the musician’s first option for altering the instrument’s sound and response characteristics. Despite this, their consistency, variable performance, durability and sensitivity to ambient conditions make it difficult for the musician to find and maintain a reed that responds to their liking. Thus it is desirable to examine the material, microstructural and anatomical properties of the reed and their contributions to vibrational performance with input from mechanical engineers, materials scientists and musicians.

The current study is part of an on-going research project, and this paper presents preliminary results. In the present work raw samples of ADL obtained from a manufacturer in pre-cut form are sectioned into longitudinal and transverse specimens for mechanical characterization. Prior to testing, samples are conditioned using an incubation system to 37 degrees Celsius and 90% relative humidity, mimicking in-use conditions of the reed. Initial microstructure analysis of each specimen is completed using optical microscopy to quantify fiber spatial arrangement, size and the existence of micro-cracks along the fiber-matrix interface. X-ray diffraction is also used to quantify the fraction of crystalline cellulose present in each sample. Specimens are then excited over a specific frequency range similar to that of in-use reeds using pressure waves in a non-contact setup. Values of internal friction are obtained as logarithmic decrement values for frequency-dependent decay. One set of specimens is then subjected to cyclic mechanical loading at low frequency (< 1Hz) and stresses up to 15MPa. The other set is maintained at the given environmental conditions using the incubator and aged through temperature and humidity cycling. Comparisons of post-testing microstructure damage and internal friction measurements are then completed to delineate specific degradation mechanisms due to mechanical/fatigue deterioration and moisture cycling. Internal friction is found to be dependent on both frequency, moisture and cyclic loading. Furthermore, the existence of microstructural cracks contributes to increasing decrement values at high frequencies in both fatigued and moisture cycled samples. Statistically significant correlations are discovered between logarithmic decrement and vascular bundle orientation at 700 Hz and logarithmic decrement and parenchyma cell diameter at 1000 Hz. Reductions in internal friction below 400 Hz indicate a decreasing loss modulus (E’’) with increased moisture cycles, although this trend will be tested against a larger sample set in further work.

Decorative, polychrome ceramics from Corinth, Greece, produced during the 8th-6th centuries B.C.E. were luxury goods widely traded throughout Greece and the Mediterranean. Corinthian pottery is the first 5-color polychrome ceramic technology, having slip-glazes in distinctive white, black, red, yellow, and purple colors, and in a variety of surface finishes from glossy, to semi-matte, to matte. The firing temperature range, 925-1075°C, was determined experimentally to be to be higher than previously reported, similar to the Corinthian amphorae and other ceramic products. This firing range is higher than that of the better known, more prestigious Athenian Black-figure and Red-figure ceramics. In this study three examples of Corinthian and one example of Athenian Black-figure ceramics from the Marie Farnsworth collection at the University of Arizona were tested and compared to thirteen clays from Corinth. Analytical techniques included Fourier-transform infrared spectroscopy (FTIR), scanning-electron microscopy with energy-dispersive spectroscopy (SEM-EDS), micro-Raman spectroscopy, and wavelength-dispersive electron microprobe (EPMA with BSE-SEM).

Artisans in Corinthian workshops experimented to change the colors of the slips by varying the type and amount of iron-rich raw material, as well as the composition of the clay used as a binder and the amount of flux used as a sintering aid to promote glass formation. Corinthian artisans developed not only different recipes to produce the various colors, but also they were able to control raw-material particle size and composition to produce variations in surface luster (matte, semi-matte and glossy). This research suggests that Corinthian polychrome-slip technology was based on careful control of particle processing, of compositional control of raw materials and their admixtures, and of firing temperature. The behavior or practice of adding different ratios of pigments and glass-forming fluxes to form various optical effects implies a detailed knowledge of what happens when these are heated and fired. This is a process of experimentation focused on developing a distinctive craft practice, which produced a distinctive and highly valued material. The Corinthians developed a more complex, easily recognizable, and culturally distinctive ceramic technology that was intentionally established as a cultural brand, and probably as a luxury brand of high socio-economic value. This research deepens our understanding of the complex pigment processing and firing technologies employed in the production of Corinthian ceramics.

From the early eighth century CE Byzantine shops next to the Synagogue and Bath-Gymnasium Complex at Sardis, Turkey, were excavated from 1958 to 1969 more than 50 pounds, or about 350 panes of transparent flat glass sheets interpreted as window glass. Examination using optical microscopy showed little variation in size, shape, thickness, edge shape, tool marks, bubble and cord elongation and alignment. Microstructural and compositional variation of weathered surfaces and unweathered cross sections were studied using scanning electron microscopy with energy dispersive x-ray analysis (SEM-EDS). Differential thermal analysis (DTA) was used to determine glass transition temperature range. Three traditional window-forming methods have been described in the glass technology literature: crown, plate and cylinder. The Sardis glass is most similar to criteria expected for cylinder glass, but significant differences were documented. Consistently patterned characteristics evidence a developed technological practice. Replicative tests were conducted using various forming sequences. Wooden and ceramic two-piece molds were made to overblow one or both ends, and hot glass threads were used to thermal shock the cylinder ends and to make a vertical crack that allowed opening during a reheating and slumping operation. These reconstructed methods fit the observed microstructural and macrostructural characteristics of the glass sheets. Analysis of glass manufacturing methods in antiquity contribute to the historical knowledge of craft practices and to the interpretation of industrial debris excavated at markets and industrial workshops.

An adhesive that can withstand elevated temperatures is necessary for the conservation of artifacts in hot climates. The use of Butvar B-98 as a modifier to raise the glass transition temperature of Paraloid B-72 was investigated. The characteristics of B-48N and B-72 blends, currently in use in the field of conservation, were used as a comparison for analysis of the B-98 and B-72 blends. Differential Scanning Calorimetry (DSC) was used to determine the glass transition temperatures (Tg) of the blends and shear testing was used to investigate the shear strength of the blends. While the B-98 and B-72 blends attained elevated glass transition temperatures and performed well during shear testing, issues regarding miscibility and phase separation of the blends were investigated using transmission FTIR, DSC, and optical microscopy.

Unusual raw materials are used to produce Tibetan black pottery in Puma township of Derge County, Sichuan Province, China. Carbonaceous, calcareous pyrite-rich illitic lakebed clay is mixed in equal proportions with a ferruginous talc-chlorite steatite. A two-stage firing process results in a dark, lustrous surface. The large amount of talc imparts many useful functional qualities to this pottery; most significant are the low thermal expansion and good thermal conduction properties of talc that make these ceramics highly suitable for heating and cooking in this high mountain region. Although used in some modern ceramics, and even in modern stoves, talc is an unusual ingredient in non-industrialized ceramics. Procurement and preparation of this resource adds to the production time but its properties and performance make talc an excellent choice for the well-being and comfort of local Tibetan households.