Red Glass Research Articles

A Validated Thermal Computational Fluid Dynamics Model of Wine Warming in a Glass

Oenophiles are aware that the temperature at the time of drinking can profoundly shape wine’s sensory attributes. Wine is usually served and drunk below room temperature but warms up after pouring due to heat exchange with warmer surroundings. This study investigates how quickly wine warms up in a wine glass and identifies the relevant heating effects. A numerical simulation using conjugate heat transfer is established, representing the complex multi-physical process. Experiments are conducted to validate the simulation. It is shown that the simulation must take into account thermal conduction, convection, and even radiation to provide accurate results. Without simulating radiation and convection of the room air, the predicted temperature is off by 66.3% or 3.3 °C. As warming is independent of the alcohol content, the simulation results are valid for non-sparkling wine types with moderate sugar levels within the considered configuration. A parameter study investigated the temperature increase over time depending on the ambient temperature and the initial wine temperature for 150 mL wine in a medium-sized red wine glass. The results can provide information on preparing a wine to obtain the desired drinking temperature.

Assessment of stereopsis in unilateral amblyopia subjects using syntonic phototherapy

ABSTRACT Introduction Amblyopia is two Snellen line difference between both eyes. Red filter therapy is a treatment option for amblyopia based on principle of syntonic phototherapy. The purpose of this study is to assess the stereopsis in amblyopic patient using syntonic phototherapy. Methods A Qusai experimental study was conducted from August 2021 to December 2021 at Madina Teaching Hospital Faisalabad. A total 30 subjects of both gender and ages ranging between 8 to 18 years were included through a non-probability purposive sampling technique. The sample was considered of 15 anisometropic amblyopes and 15 strabismic amblyope. Data was collected using a Performa and pre assessments of stereopsis by Titmus fly chart were recorded without red filter. Red filter glasses were prescribed for 4 week, post assessment data was recorded after 4 weeks. Data was analyzed by using Paired sample T test and Independent Sample T test in SPSS 20 software. Results After syntonic phototherapy significant improvement was seen, mean stereopsis was 48.00000 (p = 0.002) in anisometropic amblyopes while mean improvement of stereopsis 1.670.93333 (p = 0.00) in strabismic amblyopes. Anisometropic amblyopic patients showed significantly better improvement in stereopsis (p = 0.00) by syntonic phototherapy as compared to strabismic amblyopes. Conclusion Significant improvement was seen in stereopsis, while improvement was more significant in anisometropic amblyopes as compared to strabismic amblyopes. Children were obsessed with the red filter glasses while their parents found syntonic therapy simple plus facile and gave good results. So, eye care professionals must be aware of this new therapy and they should keep syntonic phototherapy in mind whenever they are dealing with amblyopic patients.

Changes in standing stability when wearing different colored glasses cannot be determined by participants’ subjective preference – A crossover randomized single-blinded pilot study

BackgroundThe use of individually preferred colored glasses has gained popularity with the expectation that it may improve balance control and sports performance, however, the results of previous studies remain inconclusive. Aim of the studyIn the present pilot study, we aimed to determine the association between participants’ subjective preference and standing balance performance when wearing five different colored glasses. MethodsThirteen participants stood on one or two legs on a pair of synchronized force platforms for 30 seconds with 60 seconds rest between the five-five randomized stance trials, while wearing red, blue, yellow, green, or transparent colored glasses. In addition to 7 CoP-related variables, we analyzed five features of EMG data from three lower limb muscles on both legs. ResultsNo significant effect of colored glasses was found. Some CoP (velocity: χ²(4, 13) = 10.086; p = 0.039; Kendall’s W = 0.194, root mean square [RMS]: χ²(4, 13) = 12.278; p = 0.015; Kendall’s W = 0.236) and EMG-related (RMS of biceps femoris: χ²(4, 13) = 13.006; p = 0.011; Kendall’s W = 0.250) variables showed differences between the colored glass conditions during dominant-leg stance, however, participants failed to consecutively determine these differences in standing stability. ConclusionsOverall, our results may suggest that lens color preference, irrespective of the color itself, may influence dominant leg standing balance most probably due to psychological factors, however, only subjective determination have no potential to determine the color of the glasses that would support the individual’s standing balance the most.

Ultrastability and color-tunability of CsPbI3 nanocrystals glass via doping CoBr2 and application in WLED

Extensive research has been conducted on all-inorganic CsPbI3 nanocrystals (NCs) due to their exceptional optical properties. In this study, we successfully prepared CoBr2-doped CsPbI3 NCs in Lithium-borosilicate using the conventional melting quenching approach. We investigated the optical characteristics of CsPbI3 NCs glass doped with varying amounts of CoBr2. Remarkably, the samples exhibited outstanding water and thermal stability and tunable emission ranging from 702 to 652 nm. Interestingly, the CsPbI3 NCs glasses doped with CoBr2 demonstrated significantly enhanced photoluminescence quantum yields (PLQYs), which increased from 8 % to 32 %. Furthermore, by mixing a red CsPbI3 NCs glass doped with 0.5 mol CoBr2 and a green CsPbBr3 under a blue LED chip, we effectively generated a WLED which achieved (0.3341, 0.3360) of chromaticity coordinate (CIE), 5775.35 K of a correlated color temperature (CCT) that close to positive white light (0.330, 0.330) and the color rendering index (CRI) 79.4. This study provides a new technique in the field of metal ion-doped perovskite NCs, providing a valuable reference for future research and demonstrating possible applications in LEDs.

Non-metallic decorative inlays in La Tène jewellery - contribution of archaeometry to the understanding of production technologies

The study provides a detailed investigation into several representatives of La Tène jewellery. Primarily, it deals with non-metallic decorative inlays from the Late La Tène period, particularly with their application on a metal base. Unique artefacts have been selected for the study, all coming from the Czech Republic and Slovakia. A prime representative of the finds is a torc coming from a La Tène burial site in Prague (Czech Republic, Central Europe). In this geographical context, such finds are rather exceptional. The torc examined is remarkable both in terms of its origin and the production technology utilised, namely the application of decorative inlays made of red opaque glass. Available literature classifies this decorative element as an enamel technique. The highly specific type of red soda high-lead glass applied there was examined using LA-ICP-MS. Based on the trace elements detected, it can be established that the glass is most likely related to contemporary Egyptian production. Other items of the artefact set consist of two Münsingen brooches from Moravia and an exceptional brooch from Slovakia. The latter find was found to be decorated with coral (as confirmed by Raman spectroscopy). Besides identifying the materials of the decorations, we were also able to characterize the binder between individual decorative inlays and their metal base. The analysis of the binder has revealed the presence of birch tar (determined by FTIR and GC/MS). The results obtained expand the knowledge about the production technologies applied to the jewellery from the La Tène period.

GLASS BRACELETS FROM THE TERRITORY OF ANCIENT TUROV: MORPHOLOGY AND PRODUCTION TECHNOLOGY

The article is based on the analysis of 715 copies of glass bracelets (materials of P. F. Lysenko research in 1968 and 1992) from the territory of detinets and the roundabout city of ancient Turov. The inner diameter of the bracelets, shape, color scheme and decor are determined. The diameter of most bracelets fits within the limits of 5-6 cm (82.1%), products of a larger diameter – about 7-8 cm – make up 9.1%, specimens of a smaller diameter – about 4-4. 5 cm – 8.2%. With respect to the shape, smooth products of rounded cross-section (56.8%) and twisted (38.2%) predominate, there are significantly fewer instances of sub-triangular cross-section, flat-convex, grooved and twisted. The color scheme is distinguished by the dominance of shades of green, turquoise and brown, blue, purple and yellow products are presented to a lesser extent, in single copies – from red muffled glass. Decor has 13.3% of products, the most common way is to twist the hoop with a yellow opaque thread. A group of products with a specific technological characteristic is identified – the presence of metal wire inside a glass hoop.

蕭紅香港時期小說再解讀: 以《呼蘭河傳》、《馬伯樂》、《小城三月》、《紅玻璃的故事》爲中心

As a famous modern female writer in the 20th century, Xiao Hong completed 11 collections of works with nearly one million words in just nine years. These creations of hers are divided into two stages: the mainland period and the Hong Kong period, and the Hong Kong period is the mature period and peak period of Xiao Hong's creation, which established her stable position in the literary world. In recent years, with the renaissance of Northeast literature, Xiao Hong's research has gradually increased, but there has not been an overall inspection of Hong Kong's works from the perspective of existentialism. In order to make up for this vacancy, the author chooses the two novellas Tales of Hulan River and Ma Bo'le's Second Life and the two short stories Spring in a Small Town and The Story of Red Glass written during the Hong Kong period as the research objects of this paper. Complying with the inner and outer line principles of literary appreciation put forward by the modern literary critic Liang Zongdai, and based on the theory of Paul Tillich, a representative of American existentialism, the four works are reinterpreted as a whole.

Molecular Dynamics Simulation and Viscosity Analysis of Red Mud-Steel Slag Glass-Ceramics.

The preparation of glass-ceramics with red mud and steel slag can not only solve the pollution problem caused by industrial waste slag but also produce economic benefits. It is difficult to analyze the high-temperature melt with the existing test methods, so the simulation experiment with molecular dynamics calculation becomes an important research method. The effects of steel slag content on the microstructure of red mud glass-ceramics were studied by molecular dynamics method. The results show that the binding ability of Si-O, Al-O, and Fe-O decreases with the increase in steel slag content. The number of Si-O-Si bridge oxygen increased gradually, while the number of Al-O-Al, Al-O-Fe, and Fe-O-Fe bridge oxygen decreased significantly. The number of tetrahedrons [SiO4] increased, the number of tetrahedrons [FeO4] and [AlO4] decreased, and the total number of three tetrahedrons decreased. The mean square displacement value of Si4+ and O2- increases first and then decreases, resulting in the viscosity of the system decreasing first and then increasing. The molecular dynamics method is used to analyze the structure of red mud-steel slag glass-ceramics on the microscopic scale, which can better understand the role of steel slag and has guiding significance for the experiment of this kind of glass-ceramics.

Characterisation and standardisation of different-origin end-of-life building materials for assessment of circularity

Construction and demolition waste (CDW) management and recycling practices are crucial for transitioning to a circular economy. The focus of this study was on the detailed characterisation of different CDWs (hollow brick (HB), red clay brick (RCB), roof tile (RT), concrete and glass) collected from seven different demolition sites in Turkey. The CDWs were characterised based on particle size distribution, chemical composition and crystalline nature. Pozzolanic activity was evaluated through compressive strength measurements of cement mortars made with 20% cement replacement by CDWs at 7, 28 and 90 days. The results showed that the clayey CDWs exhibited similar physical/chemical properties and crystalline structures. The compositions of the waste concretes varied significantly based on their original materials. All the CDWs satisfied the minimum strength activity index (SAI) for supplementary cementitious materials, with pozzolanic activity influenced by the fineness and silica + alumina contents. The average SAIs for the HB, RCB, RT, concrete and glass were, respectively, 84.5%, 86.3%, 83.4%, 80.7% and 75.8%. Clayey CDWs contributed to mechanical strength development, while the contribution of concretes was related to the hydration of unreacted cementitious particles. Glass exhibited the weakest pozzolanic activity due to its coarser particle size. Overall, the CDWs demonstrated suitable properties for use as supplementary cementitious materials in Portland cement based systems.

Poster Session: Learned rapid adaptation to environmental color changes generalize to a large range of colors.

When the environment changes color, vision adapts, and the world gradually appears less tinted. For repeated color changes, vision may learn to adapt faster to maintain accurate perception. We previously reported that wearing red glasses repeatedly caused the world to appear less and less reddish when the glasses were first put on, as measured by the appearance of unique yellow. Here, we tested the appearance of a larger range of colors. 13 observers wore red glasses for 5hr/day for 5 days. Observers were tested with pairs of 1.5 deg filled color circles, centered within a 6deg black square on a background image. 13 colors were chosen from LAB space comprising unique and intermediate hues at two contrast levels, and one gray. Observers rated the difference between each possible color pair on a scale of 0 to 9. Observers performed the task before and immediately after putting the glasses on, and after 25, 50 and 75 min of wear. Wearing red glasses caused all colors to appear reddish and be rated as relatively similar. As observers adapted, colors gradually regained more normal appearance, and the similarity between color pairs decreased. Critically, over days, color pairs appeared more dissimilar immediately after putting on the glasses (p<1e-6). Multi-dimensional scaling analysis of the similarity data revealed a uniform expansion of color space across days. Thus, observers learned to immediately adjust their perception of many colors with repeated experience.

Reflections into Ptolemaic Glass II: Characterizing Yellow, Yellowish‐orange, Red, and Brown Inlays from Tebtynis

AbstractA systematic and extensive analytical study was carried out on the loose inlays discovered in the Ptolemaic workshop of Tebtynis (Fayum oasis, Egypt). This paper presents data derived from the multi‐methodological archaeometric investigations (optical microscopy, scanning electron microscopy–energy‐dispersive spectroscopy, electron probe microanalysis, micro‐Raman spectroscopy) performed on a set of intentionally colored and opacified glasses. In particular, we will discuss the textural, chemical, and mineralogical results related to the study of the yellow, yellowish‐orange, red, and brown inlays and semi‐finished/waste products now preserved at the Museo Egizio, Torino. The results highlight the presence of natron (low‐magnesium glasses, LMG) and plant ash (high‐magnesium glasses, HMG) base glass, coexisting with intermediate composition. Yellow samples are opacified using lead antimonates doped with iron and sometimes tin; conversely, yellowish‐orange specimens and the only brown sample are characterized by nanocrystals of cuprite. Red glasses are found in two variants: Dull reds are HMG with colloidal metallic copper particles, while sealing‐wax reds show LMG composition, associated with dendritic cuprite dispersed in a transparent, greenish matrix.

Synthesis and characterization of geopolymer from “In Natura” red mud and glass waste

AbstractThe use of red mud in the geopolymer production is an attractive method for managing this waste. However, the processing steps usually applied, such as drying and grinding, can significantly increase the material processing costs, and consequently increase the cost of the final product. In this study, geopolymers were developed using red mud “in natura” (non‐processed slurry) and glass waste powder. Parameters including SiO2/Al2O3 ratio (4, 5, and 6), NaOH solution (6, 8, and 10 M) and curing duration (10, 28, and 56 days), were examined to understand the extent and degree of geopolymerization. Compressive strength tests were performed along with the analysis of their microstructural characteristics using quantitative x‐ray diffraction (QXRD) analysis based on Rietveld's refinement method, scanning electron microscopy (SEM), and thermal analysis (TG and DTA). As a result, higher SiO2/Al2O3 ratios and NaOH solution concentrations generally lead to greater compressive strength, which ranges from 9.7 to 43.1 MPa. Microstructural and compositional analyses demonstrated that the final products consist of an amorphous geopolymer binder, crystalline phases originating from raw RM and a neoformed phase, Garronite. This study showed that the RM without any processing step displays a high potential in the geopolymer production.

The role of tin and iron in the production of Spanish copper red glass from the 19th to the 20th century

Little is known about the materials used in the manufacture of red window glass in the 19th and the first decade of the 20th century. Here, we have studied fragments from eight Spanish glasses from the 19th and 20th centuries. The red glasses consist of a single layer of red glass on a colourless glass substrate. The chemical composition, oxidation state, nature of colourants and crystalline precipitates were determined by a selection of microanalytical techniques. In the study, we have found that the red colour of the glass is due to the presence of Cu0 nanoparticles, the red glass layer has lower calcium content than the substrate glasses, which we found favours copper being present in the glass predominantly in Cu+. They also contain tin and iron while lead, described in historical and modern documentation, was absent. Tin must have been added to the glass as a Sn2+ compound and acted as a reducing agent for copper. Iron is also a well-known reducing agent, but does not act as such in the red glasses studied here. However, it may have facilitated the reduction of copper to Cu0 by promoting its incorporation into the glass as Cu+ rather than Cu2+.

Fragments of luxury: Opaque glass from the Palace of Mystras, Greece

The present study focuses on the analysis of nine opaque or translucent glass samples of white, grey/blue and red colour, recovered from the Palace Complex of Mystras in southern Peloponnese, Greece. Their date cannot be determined with specificity but has to span between the mid-13th and mid-19th c. AD, the period since the construction of the site and throughout its continuous use as the administrative centre of the Despotate of Mystras. The extremely rare occurrence of opaque glass vessels of this period in Greece, as well as the recovery of most samples within Building E of the Complex, suggest that the samples were precious objects, possibly owned by high ranking members of the Palace. A multi-technique approach, including Optical microscopy, SEM/EDS, Raman spectroscopy and TEM analysis, was implemented in order to determine the microstructure and raw materials of the samples.Despite the small number of samples, a remarkable variability was revealed in terms of the raw materials and manufacturing processes employed. Overall, three different opacification techniques were documented among the white and grey/blue samples: The Na-rich glasses were opacified using either cassiterite, a typical opacifier for the period, or calcium antimonate, a less common opacifier in the post-Medieval glassmaking. The K-rich white glasses were opacified with the addition of the ashes of animal bones, as suggested by the presence of calcium phosphates, a Byzantine tradition that was possibly also used by Bohemian glassmakers.Finally, the red glasses present certain atypical traits in their microstructure and chemical composition. The samples contain multiple calcite, tin oxide and lead oxide particles. The colour is due to copper, which could only be identified with the application of TEM analysis, in the form of copper oxide nanoparticles.The present study highlights the complicated traditions employed for the production of opaque glass in the post-Medieval European workshops and it underscores the need for a more thorough study of related material.

A literature review of the latest trends and perspectives regarding alkali-activated materials in terms of sustainable development

The purpose of the paper was to analyze trends in the formation of alkali-activated materials (AAMs) produced from alternative starting materials to blast furnace slags and fly ash. The research was reviewed on the basis of literature data from the past few years, which shows that the researchers are increasingly paying attention to the possibility of synthesis of AAM from such waste materials as industrial slags and ashes, concrete and demolition waste, red brick waste and glass waste. This is driven by the need to find competitive solutions to the commonly used blast furnace slags and fly ashes in the cement industry, which are also a source for obtaining traditional AAM. Analysis of material solutions has shown that these materials are being successfully used to produce new AAMs, with most of them being only a partial replacement for slags and fly ash. The article also points out that silicon- and aluminum-rich waste materials such as red mud, rice husks, and waste glass can be successfully used to activate AAMs materials, in place of typical activators in the form of sodium silicates or hydroxides, which in turn contributes to lowering the carbon footprint of AAMs. However, the future of this type of solution depends on several factors, the most important of which seems to be the understanding of the polymerization mechanisms of the more complex aluminosilicate systems and the achievement of reproducible physical and chemical parameters of AAM, resulting in strong and durable binders and, ultimately, construction materials made from them.

Silver nanoparticles doped heavy metal oxide borate glasses: luminescence and spectroscopic investigations

The effects of silver nanoparticles (NPs) embedded with samarium (Sm3+) ions doped on luminescence intensity of borate glasses was fabricated and evaluated using a method that is conventionally known as melt quenching. XRD study proved material's amorphousness. TEM examination determines average nanoparticle size distribution. Vibrational and structural units determined by FTIR and Raman spectra. DTA thermograms identify Tg, To, and Tp. XPS allows one to identify chemical shifts in addition to binding energies. Localized surface plasmon resonance (LSPR) band that has been identified is located at around 400 nm. It is a hypersensitive transition and enhancement of PL intensity due to the energy transfer from AgNPs to Sm3+ ions. A high-intensity emission peak can be seen at 599 nm (orange red), which is attributed to the electric dipole transition 4G5/26H7/2 of Sm3+ ions.The PL intensity non-linearity should be affected by the silver ion concentration. This happens because the energy is being transferred reverse, from the Sm3+ ions to the AgNPs, causing the PL intensity to oscillate in an anisotropic fashion. Analysis of the CIE diagram of glass system with Sm3+ ions suggests that it may be useful as a red luminous glass matrix in various photonic device implementations.

Glass volume or shape influence the aroma attributes of Cabernet Sauvignon dry red wine

AbstractThe enjoyment of the wine depends not only on the properties of wine itself, but also on the wine glasses. The present study was designed to investigate whether the glass volume or shape would influence aroma attributes of Cabernet Sauvignon dry red wine. Sensory evaluation was conducted with a 12‐member panel. Three‐alternative forced‐choice (3‐AFC) tests were chosen to determine whether any difference in odors could be perceived among samples in glasses of two shapes (Bordeaux and Burgundy glasses) or in glasses of three volumes (350, 500, and 650 mL). Also, 12 participants evaluated their experience of “intensity,” “elegance,” and “overall aroma quality”, as well as descriptive analysis of the wine aroma. The results showed the wine was perceived as being more intense and more elegant in the glass with a smaller cuppa height and a bigger ratio between the maximum and opening diameter. These findings further support the idea that tasters' perceptions of wine aroma are influenced by the shape and volume of wine glasses, which are in part closely related to the parameters of the glasses.Practical ApplicationsInvestigating the effects of two major red wine glasses, Bordeaux and Burgundy glasses, on the aroma attributes of Cabernet Sauvignon dry red wine is very useful to match the wine with the appropriate glasses. In order to highlight the intensity and elegance of the wine aroma, it is essential to choose a glass with a smaller cuppa height and a bigger ratio between the maximum and opening diameter, which is practical and instructive for wine practitioners, connoisseurs, sommeliers, enthusiasts, and consumers with higher olfactory sensitivity.

The role of sulphur in the early production of copper red stained glass

Little is known about the production of ruby red copper stained glasses from the Medieval and Renaissance periods apart from the fact that the colour is due to the presence of small metallic copper nanoparticles and that tin, the most common reducing agent used in copper red glass production since the 19th century, is not present. In fact, very few workshops in Europe were able to make red glass in historical times, and they kept it secret, so very little is known about how it was obtained. These workshops exported the red glass throughout Europe. Recently, the presence of copper sulphide particles and the data obtained in the replication red glass following historical recipes suggested that sulphur might be the key ingredient in this process.Here, a collection of historical red glasses from these periods has been analysed using a combination of microanalytical techniques; Electron Microprobe (EM) and Field Emission and Scanning Electron Microscopy (FESEM) to verify the chemical composition and nanostructure of the glasses, Synchrotron radiation micro-X-Ray Diffraction (micro-XRD) to establish the nature of the nanocrystalline precipitates, and S, Cu and Fe K-edge micro-X-Ray Absorption Spectroscopy (micro-XAS) to determine the speciation. The data obtained show that the oxidation of S2− into S6+ in the glass is responsible for the precipitation of copper nanoparticles. The development of a sulphide-silicate partition and the presence of Fe3+ in the melt give rise to the precipitation of the high-pressure tetragonal polymorph of chalcocite (Cu2S). Differences between the Medieval and Renaissance red glass are determined.

A comprehensive study on the compressive strength, durability-related parameters and microstructure of geopolymer mortars based on mixed construction and demolition waste

As a viable option to upcycle construction and demolition waste (CDW) into value-added materials, geopolymer technology is emerging. Most studies investigate CDWs in a separated form or in combination with mainstream pozzolanic/cementitious materials focusing only on fundamental properties of geopolymer pastes, not considering to scale such materials to the level of their application in the forms of structural mortars/concretes or to characterize long-term performance/durability. This study investigated the development and characterization of ambient-cured mortars with mixed CDW-based geopolymer binders and untreated fine recycled concrete aggregates (FRCA). Mixture of CDW-based roof tile (RT), red clay brick (RCB), hollow brick (HB), concrete (C), and glass (G) was used as the precursor, while ground granulated blast furnace slag (S) was used in some mixtures to partly replace CDW precursors. Compressive strength, durability-related parameters including drying shrinkage, water absorption, and efflorescence, microstructure and materials sustainability were evaluated. Results showed that 28 d compressive strength results above 30 and 50 MPa are achievable with the entirely CDW-based and slag-substituted mortars, which were found improvable to have entirely CDW-based structural concretes. Drying shrinkage of the mortars is slightly higher than that of conventional cementitious/geopolymeric systems although it can be minimized significantly through mixture optimization. Water absorption values remain comparable with the literature. CDW-based geopolymer mortars outperform Portland cement mortars in terms of CO2 emission and energy requirement. Our findings show that via utilizing CDW-based constituents in mixed form as precursor and waste aggregates, it is possible to develop greener construction materials with acceptable strength and long-term performance.

Simply red: A Late Bronze Age glass ingot from Amarna

Chemical analysis of a visually opaque, turquoise-blue ingot from the Late Bronze Age royal capital at Amarna, housed in the Garstang Museum, University of Liverpool, shows an excess of copper colourant which indicates that the intended colour was opaque red. Trace element analysis places the location of manufacture in Egypt, and the date, finds location, dimensions and analysis suggest that the glass was made at Amarna. This, coupled with other recent finds of ingots/part ingots at the site, suggests that Amarna was producing not only blue glass, but a variety of different colours in this early period of Egyptian glassmaking. Other royal locations, such as the later site at Qantir where red glass predominates, appear to specialise in specific colours. These findings suggest that the political and economic focus of different ruling elites during the New Kingdom (1550–1069 BCE) influenced the volume and range of colours of the glasses manufactured.