Colored Gems

Plant growth regulators can influence fruit yield and quality. This study aimed to evaluate the effect of cytokinin and gibberelin on the agronomic and physicochemical characteristics of banana fruits cv. ‘Prata’ (Musa spp. AAB), according to the formation period and position in the bunch. The experiment was conducted in a completely randomized 2 x 5 factorial design, two periods of bunch development (summer and winter), five treatments and ten replicates. To study the effect of position in the bunch, split plot was adopted, considering in the plot, 2 x 5 factorial and in subplots, hand 1, hand 4 and last hand. Treatments consisted of 2 pulverizations with water, 150 mg L-1 cytokinin, 200 mg L-1 of gibberellic acid, 100 mg L-1 of cytokinin plus 200 mg L-1 of gibberellic acid and 200 mg L-1 of cytokinin plus 200 mg L-1 of gibberellic acid, applied from the fourth to the last hand of the bunch. Cytokinin and gibberellin, alone or associated, regardless of formation period and position...

This study delves into strategies aimed at reducing Total Dissolved Solids (TDS) in water sources throughout Andhra Pradesh, India, with a specific focus on Vijayawada, Rajahmundry, Bapatla, Nellore, and Rangampeta. These locations represent a spectrum of water quality challenges, reflecting the diverse nature of TDS issues across the state. Our investigation spans various TDS reduction techniques, encompassing conventional methods such as Borax Powder and Multi-Effect Evaporators, natural alternatives like Vetiver Root, Gooseberry Bark, and Lemon Peel, as well as commercially available options including Peanut Husk, Sodium Citrate, Sodium Sulphate, and Sodium EDTA Solution. The overarching objective is to develop a practical framework for optimal TDS reduction strategies tailored to the unique factors of each location. Through rigorous evaluation of the efficacy and cost-effectiveness of each technique, we aim to empower stakeholders with the necessary insights for informed decision-making in clean water management across Andhra Pradesh. By conducting a comparative analysis of conventional, natural, and commercial methods, this study offers comprehensive insights into addressing TDS issues while considering both effectiveness and economic viability. The strategic selection of these specific locations within Andhra Pradesh facilitates a nuanced understanding of the diverse water quality challenges prevalent within the state. This ensures that the framework developed through this research can effectively address the varied needs and circumstances encountered across different regions. Ultimately, the findings of this study hold the promise of significantly enhancing water quality and accessibility in Andhra Pradesh, while also offering valuable lessons and insights applicable to similar regions grappling with TDS-related issues globally.

Films that deal with World War II-whether their narratives are concerned primarily with the war itself, the aura from which it emerged, or the ethos of its aftermath-have a particularly charged relationship to the presence or abjuration of color. As representations of a period that produced its own black-and-white archival footage, these works reckon with color not simply as an aesthetic choice, but also as a tool through which to define their own relationship to perspectival subjectivity and claims of historical authenticity. By examining the role of color in three vastly different World War II films-Andrzej Wajda's black-and-white 1958 rendition of the war's last 24 hours in "Ashes and Diamonds," the Harlequin prewar chaos of Bob Fosse's 1972 "Cabaret," and the delicate balance of color and black-and-white characterizing the postwar divided Germany of Wim Wenders' 1987 "Wings of Desire"-we may access a richer understanding, not simply of the films' stylistic approaches, but also (and perhaps more significantly) of their relationship to both their origins and audience. Color, that is, acts in these three films as a chromatic guide by which to untangle each respective text's take on both subjectivity and objectivity.

This article chronicles practical use of magnets in the identification and separation of gemstones based on their magnetic properties. The narrative explores how a simple idea—testing gems with a neodymium magnet—led to the development of a novel and accessible tool for gem identification. Feral’s experiments revealed that many gem species exhibit measurable magnetic responses due to trace paramagnetic elements such as iron and manganese. The article discusses key milestones in the process, including the adaptation of rare-earth magnets, the identification of diagnostic magnetic behaviors, and the formulation of comparative susceptibility tests. Through empirical testing and systematic observation, Feral established a new, non-destructive method for distinguishing between visually similar gems, particularly in the garnet group and among synthetic/natural analogs. This work represents a significant contribution to the field of gemology, offering a low-cost, field-portable alternative to more complex instruments.

Fluorescence is a well-documented optical phenomenon in many gemstone species but is rarely associated with garnets, which are traditionally considered non-fluorescent. This article presents a systematic examination of garnet fluorescence based on direct observation and testing of several hundred gem-quality specimens across multiple species and localities. The study reveals that approximately 50% of tested garnets exhibit measurable fluorescence under long-wave or short-wave ultraviolet light, with the most pronounced effects observed in members of the pyrope-spessartine series. The fluorescence is attributed primarily to the presence of activator elements such as manganese and chromium, and is suppressed in the presence of iron. The article includes spectral data, visual documentation, and analysis of the correlation between chemical composition and fluorescent response. These findings challenge longstanding assumptions about garnet behavior and suggest that UV fluorescence may serve as a supplementary tool for identifying garnet varieties and understanding their geochemical origins.

Part two of this paper discusses tools and techniques the author uses to detect chromium and vanadium in gemstones, and how to differentiate between the two chromophores. Testing with a UV-Vis-NIR spectrometer, UV flashlight, blue laser,  Chelsea filter and neodymium magnet are discussed. An important fact not generally recognized in gemology is that vanadium is a powerful quencher of fluorescence, able to quench the red fluorescence of chromium at least as effectively as iron. Intriguing information about the role of chromium, vanadium and iron in creating color in Beryl gems such as emerald and aquamarine is discussed in detail.

Part one of this two-part paper investigates the role of chromium and vanadium in creating green color in gemstones. Does vanadium create exactly the same green color as chromium? After analyzing numerous examples of green gems, the author concludes that vanadium has the potential to create a strong green color as readily as chromium, and that green color from vanadium can be indistinguishable from green color from chromium. The paper describes how many green gems with names containing the word “chrome”  are actually colored primarily by vanadium.

The article “Separating Look-alike Gems with a Magnet”, published in the March 2020 issue of Gemmology Today, explores the innovative use of magnetic testing as a rapid, non-destructive method for distinguishing visually similar gemstones. Author Kirk Feral demonstrates how a simple handheld magnetic wand—equipped with a high-strength neodymium magnet—can be employed to differentiate natural, synthetic, and imitation gems that otherwise appear identical to the naked eye. The paper presents numerous case studies involving diamond, garnet, spinel, jade, turquoise, tourmaline, sapphire, and other gem species, illustrating how differences in magnetic susceptibility—resulting from varying concentrations of iron, manganese, nickel, and other trace elements—yield consistent diagnostic responses. The author outlines two key techniques: direct magnetic attraction and floatation testing, allowing for the detection of even subtle magnetic behavior. By integrating magnetism into standard gemological practice, this study affirms the magnetic wand as one of the most versatile tools available for field and laboratory gem identification.

The article “Pastel Pyrope: A New Garnet Variety?” published in the December 2019 issue of Gemmology Today examines the gemological and compositional characteristics of a group of light-colored garnets that deviate from the deep red hues typically associated with pyrope. Until now, the composition of such garnets has not been systematically studied.  By plotting composition using magnetic susceptibility and refractive index, the author determines that these pale pink to lavender garnets constitute a distinct garnet variety with known compositional boundaries. The study identifies elevated levels of manganese and lower concentrations of chromium and iron as key contributors to the stones’ muted color palette. The paper also discusses the implications of naming conventions in the gemology and the practical market significance of pastel pyrope.

A simple and readily available tool to measure thermal conductivity (or thermal inertia) in gemstones is one of the most useful tools gemologists have for gem identification. It is also a highly under-utilized tool whose application in gemology has received little attention. Different gems exhibit distinct thermal responses that can be easily measured. This article highlights the use of the SmartPro Gem-Eye 1 thermal conductivity meter, which measures how quickly a gemstone's surface temperature (thermal inertia) changes when exposed to heat at a small point on the gem. Feral has established a Thermal Conductivity Index for over 80 gemstone types, providing gemologists with a practical guide for distinguishing between gemstone species. This insight underscores the value of thermal properties as a non-invasive, cost-effective method in gemological analysis.

Axinite is a mineral group consisting of four species, three of which produce gem-quality material. These species are in solid solution, and every axinite gem is a mix of one or more species. The relative composition of individual axinite gems can be evaluated using simple magnetic testing. Over 55 Axinite samples were tested among the 4 species of axinite, including rare examples of lavender, pink, and orange axinite, as well as examples of axinite with blue and green color zoning. It was found that magnetic testing provides a simple way to separate magnesioaxinite from manganaxinite. This study also reports and documents for the first time a manganaxinite with pink color. New evidence of significant miscibility between magnesioaxinite and manganaxinite is also presented.

Even though, Ethiopia is endowed with suitable geological setting to host varieties of gemstones, it has not yet been well investigated and explored. In Northern Ethiopia, Tigrai regional state, sapphire mineral has been extracted by traditional and artisanal miners. Chilla, which is 35 km north of Axum, is one of the sapphire's artisanal mining activities has been practiced. In Ethiopia, particularly in Chilla area there is no any geological and geochemical study on Sapphire mineral and its host rocks. In Chilla area, most of sapphires are found in alluvial or eluvial deposits, making it grim to study the relationship between the sapphires and their host rocks. Here, we present preliminary geological characteristics of sapphire mineral within alkaline basalts from the tertiary Chilla volcanic terrain. Geological investigation and geochemical analysis (XRF) indicates; the sapphire mineral is hosted in tertiary alkaline basalts and occur in the contact between alkaline basalt and intrusive granite rocks.

Although more than 4,000 minerals have been discovered in the world to date, some of them are very valuable in terms of collection because they are very rare in nature. One of the rarest and most valuable minerals in the world is painite [CaZrB(Al9O18)]. After its discovery in Myanmar (Burma) in southeast Asia in the 1950s, research has been constantly carried out on the possibility of this rare collectible and jewelry stone being found in other countries, due to its very high value. The main purpose of this study is to reveal whether the mineralogical and gemological properties of the mineral painite can be searched for and found in Türkiye. It is known that painites are geologically formed and found in skarn belts at the contact of leucogranite of magmatic origin and marbles of metamorphic origin. As a result, if painite is to be sought in Türkiye and evaluated as a gemstone, the percentage amounts of the elements Ca, Zr and B must be taken into consideration as well as corundum, spinel, etc. in the geochemical composition of this mineral. It should be searched in the geological environment of minerals; in particular, metamorphism contacts (skarn belts) and/or their alluvium should be investigated at the contact between igneous rocks and carbonate rocks.

Keywords: Painite, ruby, rarest gems, gemological characteristics.

Leopard moth, Zeuzera pyrina L. is one of the most important wood borers which causes heavy damage on walnut in different parts of Iran, especially in Chaharmahal va Bakhtiari province. In this research, efficiency of two pheromones (Synanthedon tipuliformis Clerkand Z. pyrina), two forms of pheromone traps (Delta and Funnel) and five installing height (4, 6, 8, 10 and 12 m above the ground), to catch male leopard moths were studied. Pheromone traps were installed in the walnut orchards at the second decade of May (before the adult emergence). Number of caught moth were recorded weekly and finally mean number of caught moths per trap were compared statistically among treatments. Results showed significant difference between pheromones and the pheromone of Z. pyrina was captured more number of the moths, whereas there was no significantly difference between traps (delta and funnel traps). Results of both years of the experiment showed installing height had a significant effect on the capturing of the male moths, and with increasing the height of installation, number of captured moths increased significantly. Mean number of caught moths per week were 1.38, 2.43, 7.77, 10.68 and 16.17 at the height of 4, 6, 8, 10 and 12 meters, respectively. In other words, the number of caught moths at the heights of 12 and 6 meters (above ground level) were11.6 and 6.59 folded of the 4 meter height, respectively. Based on the obtained results, trap form and installation height of the traps have significant effect on number of the caught leopard male moths by pheromone traps.

This paper focuses on the latest research about the marble fragments found during the archaeological investigations carried out since 2007 by the Department of History and Cultures of the University of Bologna, within the Ostia Marina Project, here presented as a continuation, deepening and updating of the contribution made at Asmosia Conference X (2010). Investigations continued fruitfully over the years and led to a further expansion of the excavated area, with the addition to the thermal complex named the "Silenus Baths" (sector A), of new structures from sector B, among which the significant discovery of a new mithraeum stands out, referred to as being "of the colored marbles". The spelaeum of this mithraeum still preserves the nearly intact pavement made with many different types of reused marble. Technical and archaeological investigations of the pavement are here presented, as well as the results of the quantitative and qualitative analysis of the marbles.

Colored fringe pattern approach has been proposed to overcome the limitations of the sequential phase-shifting fringe pattern profilometry for dynamic measurements. However, the use of colored fringe patterns leads to a mayor problem, the color cross-talk, which has been considered to be equivalent to reconstructing the phase map from the fringe patterns with unknown phase shifts. Therefore, phase error is introduced when conventional phase-shifting algorithms with fixed phase shift values are used to retrieve the phase. To overcome the cross-talk issue, we propose the use of a fringe pattern normalization algorithm to achieve the intensity modulation balance among the different color channels and then the use of an advanced iterative algorithm to retrieve the phase. Simulations and experimental results show that the proposed procedure can significantly reduce the influence of the color cross-talk.

The aim of this work was to determine the bagging time of ‘Prata Anã’ banana in order to reduce anthracnose disease. Treatments consisted of protection of banana bunches with TNT bags at emission, 30, 60, 90 and 120 days after emission and of unpacked bunches. Fruits were collected, stored in refrigeration chamber (25 ± 1 °C and 80 ± 5% RH) and evaluated for anthracnose incidence and severity. The study design was completely randomized with six treatments, repeated over two years. Data were submitted to analysis of variance and Tukey test (p <0.05). The physical and chemical characteristics of stored fruits were evaluated every three days for 12 days. The study design was completely randomized with six treatments, four evaluation periods, repeated over two years. Results were submitted to analysis of variance and regression (p <0.05). The anthracnose incidence was reduced by up to 67% by bagging bunches at emission. Bunches bagged at emission and at the first month of developm...

An indicator paper based on a mailing label treated with a mixture of two dyes changed color in the presence of microstickies in water. The indicator paper consisted of a polyacrylate-coated mailing label that was dipped in a mixture of Safranin O and Astrazon Green dyes and dried. The treated label was then dipped in process water and re-dried. The color on the adhesive side of the label changed in the presence of microstickies. Optical (RGB, red, green, blue) analysis confirmed the stickies-induced color changes. During re-drying, the microstickies chromatographically separated the two dyes to a small extent across the thickness direction of the label leading to the color change. The theoretical detection limit for microstickies is 150 ppm, while the practical limit is about 400 ppm.

People with strong synesthetic perceptions of e.g. colored letters or digits (so-called 'synesthetes') seem to have good memory abilities. Synesthetes report they use their colored letters to memorize names and use their colored time lines to plan their diaries. Does the memory of synesthetes work different from that of nonsynesthetes? To answer this question three sources of information on synesthesia and memory were reviewed: 1) laboratory experiments, 2) in-depth interviews, and 3) autobiographical novels. Laboratory experiments with synethetes (individuals and groups) show that some synesthetes have an extraordinary recall but, on the average, synesthetes and non-synesthetes perform equally on recall tests. In-depth interviews show that synesthetic perceptions can enhance the emotional charge of childhood memories, help in evoking vivid, empathic memories that sometimes are therapeutic, and are influential on constructing the memory picture (e.g. its colors). The novelists Proust and Nabokov show, in their long-term analyses of their childhood memories, that these are physically very vivid evocations of the past, but in no way factual like photographs. Memorizing is a way of mentally and physically reliving and reconstructing the past from the present perspective. The self-declared synesthete Nabokov did not differ much from the nonsynesthete Proust in this respect. It is concluded that the memory of synesthetes in general does not work very differently from nonsynesthetes, but some individuals have developed an extraordinary memory by using their synesthetic perception as mnemonic tool, as a anthropological resource for orientation to navigate through the past, and as a sensibility to empathize and understand it.

Instant Insanity [1] consists of four cubes, each of whose six faces are colored with one of the four colors: red, blue, white, and green. The object is to stack the cubes in such a way that each of the four colors appears on each side of the resulting column. See figure 1 below [2]. Traditionally, this could be solved using graph theory. However, in this article, we introduce a new technique to solve the problem without using graph theory. We also used a Perl programming language to implement the new approach for the Instant Insanity.

Instant Insanity [1] consists of four cubes, each of whose six faces are colored with one of the four colors: red, blue, white, and green. The object is to stack the cubes in such a way that each of the four colors appears on each side of the resulting column. See figure 1 below[2]. Traditionally, this could be solved using graph theory.However, in this article, we introduce a new technique to solve the problem without using graph theory. We also used a Perl programming language to implement the new approach for the Instant Insanity.

Films that deal with World War II-whether their narratives are concerned primarily with the war itself, the aura from which it emerged, or the ethos of its aftermath-have a particularly charged relationship to the presence or abjuration of color. As representations of a period that produced its own black-and-white archival footage, these works reckon with color not simply as an aesthetic choice, but also as a tool through which to define their own relationship to perspectival subjectivity and claims of historical authenticity. By examining the role of color in three vastly different World War II films-Andrzej Wajda's black-and-white 1958 rendition of the war's last 24 hours in "Ashes and Diamonds," the Harlequin prewar chaos of Bob Fosse's 1972 "Cabaret," and the delicate balance of color and black-and-white characterizing the postwar divided Germany of Wim Wenders' 1987 "Wings of Desire"-we may access a richer understanding, not simply of the films' stylistic approaches, but also (and perhaps more significantly) of their relationship to both their origins and audience. Color, that is, acts in these three films as a chromatic guide by which to untangle each respective text's take on both subjectivity and objectivity.

In this paper, we apply computer algebra (MAPLE) techniques to calculate the N-colored Jones polynomial of the trefoil knot and the figure eight knot. For this purpose, a computer program was developed. When an integer N P 2 is given, the program calculates the N-colored Jones polynomial of the trefoil and the figure eight knot.

A classical approach to Multi-agent Path Finding assumes an offline construction of collision-free paths that the agents blindly follow during execution. k-robust plans can be executed without collisions even if an agent is delayed for at most k steps. In the paper, we propose a novel concept of robustness that uses alternative paths to which the agents are diverted in case of delay. Such plans can be found with much higher chances than k-robust plans.

There are several banana cultivars resistant to Black Sigatoka disease and to Panama disease, but due to the lack of information regarding post-harvest characteristics, many are rejected in the market. Nitrogen and potassium fertilization may help to improve the sensory characteristics of ripe banana, but there is lack of studies on its effects on banana cultivation, especially those resistant to diseases. The aim of this study was to evaluate the post-harvest characteristics of ‘Prata-Anã’, ‘BRS Platina’ and ‘PA94-01’ banana cultivars at four N and K2O fertilization levels (NK0: no fertilization, NK1: 175 and 285 kg ha-1 year-1, NK2: 350 and 570 kg ha-1 year-1, NK3: 525 and 855 kg ha-1 year-1, respectively) in three production cycles. It could be concluded that N and K doses adopted in this work did not influence the post-harvest physicochemical characteristics of ‘Prata-Anã’, ‘BRS Platina’ and ‘PA94-01’ banana cultivars. Regardless of N and K doses, ‘Prata-Anã’, ‘BRS Platina’ and ...

This research paper addresses the issue of excess ash content in CFBC boilers when lower quality fuel, such as the lower or upper layer of lignite, is supplied. The increase in ash content leads to the continuous draining of bed ash and often results in the restriction of bed material flow in the furnace inlet pipe to the slag cooler. While this may not have a significant impact on the required load in normal conditions, it can severely affect the unit's load capacity in the case of poor-quality coal. The paper proposes a solution for waste slag management using air blasters in 135 MW CFBC boiler, which can effectively prevent the choking of inlet pipes and ensure uninterrupted operation at the required load capacity. The implementation of this solution has the potential to significantly improve the operational efficiency and reliability of CFBC boilers, particularly when using lower quality fuels.

Plant growth regulators can influence fruit yield and quality. This study aimed to evaluate the effect of cytokinin and gibberelin on the agronomic and physicochemical characteristics of banana fruits cv. ‘Prata’ (Musa spp. AAB), according to the formation period and position in the bunch. The experiment was conducted in a completely randomized 2 x 5 factorial design, two periods of bunch development (summer and winter), five treatments and ten replicates. To study the effect of position in the bunch, split plot was adopted, considering in the plot, 2 x 5 factorial and in subplots, hand 1, hand 4 and last hand. Treatments consisted of 2 pulverizations with water, 150 mg L-1 cytokinin, 200 mg L-1 of gibberellic acid, 100 mg L-1 of cytokinin plus 200 mg L-1 of gibberellic acid and 200 mg L-1 of cytokinin plus 200 mg L-1 of gibberellic acid, applied from the fourth to the last hand of the bunch. Cytokinin and gibberellin, alone or associated, regardless of formation period and position...

Citrus leaf-miner, Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae), is one of the pests limiting citrus species in Khuzestan. The damage of six citrus species to this pest was evaluated in Ahvaz region orchards. For this purpose, 10 cm long twigs from each tree of the first instar of larvae were randomly selected and covered with a sleeve trap. Then, the date of infection, number of eggs, larvae, pupae, adults, and the duration of larval and pupal stages were recorded daily. There was a significant difference between the studied traits in this experiment. The highest average length of the larval period was related to orange (11.75±0.47 days) and the lowest average of tangerine (6.50±0.28 days) was recorded. Also, the highest mean pupal period was related to key lime (12.66±0.88 days) and grapefruit (11.66±0.67 days), and orange (5.00±0.07 days) had the lowest average. The highest number of pest different life stages was recorded in orange fruit (eggs: 10.75, larvae: 10.25, pupae: 9.75 and adults: 9.25) and the lowest number was observed in sweet lemon (eggs: 4.75, larvae: 4.00, pupae: 3.50 and adults: 3.50). The level of contaminated leaf area showed that the highest average of orange (0.82±0.05) and the lowest average of sweet lemon (0.35 ± 0.05) were recorded. According to the parameters studied, orange have suffered maximum and sweet lemon and Grapefruit minimum damage from pest attack.

The Bo Rai alluvial gem field in Trat Province, eastern Thailand, was a major mining site for Thai ruby during the early 1980s, and this material continues to circulate in the gem market worldwide. For this study, approximately 1,000 Bo Rai ruby samples were examined and pre-screened for mineral inclusions. The rough stones usually formed platy, waterworn, tabular crystals with etched or resorbed surfaces. UV-Vis-NIR spectroscopy indicated a relatively high Fe content, which was confirmed by trace-element analysis. Solid inclusions typically consisted of Al-rich pyroxene, plagioclase and pyrope with subordinate sillimanite and spinel (both of which are reported here for the first time), as well as sulphides and silicate melt inclusions. The inclusion assemblage of pyroxene, plagioclase, pyrope and spinel closely resembles the mineralogy of mafic granulite xenoliths in alkali basalt associated with the Bo Rai gem field, which supports ruby formation in mafic granulite prior to being transported to the earth's surface via basaltic eruptions.

Various types of xenoliths embedded in basalts within Bo Rai ruby deposit, Trat Province, eastern Thailand can be petrographically subdivided into three main types: (1) peridotites (Ol-Cpx-Opx-Sp bearing xenoliths), (2) clinopyroxenites (Cpx-Sp-Grt±Ol±Opx bearing xenoliths) and (3) mafic granulites, including garnet-and corundum-bearing type (Pl-Cpx-Sp±Grt±Cor bearing xenoliths). Peridotitic xenoliths, Type 1, have characteristics of a depleted mantle provenance and are varying from lherzolite to harzburgite and dunite. Type 2 xenoliths have petrological and geochemical characteristics of a cumulate. Clinopyroxene, spinel and garnet are commonly found whereas olivine, orthopyroxene and plagioclase may be present in the nodules. Type 3 xenoliths represent another type of a cumulate rock. Based on textural and mineral chemical evidence, the cumulate type xenoliths were overprinted by a few metamorphic events. The whole-rock geochemistry indicates clearly a differentiation of these xenoliths. MgO contents decrease continuously from peridotite (type 1) to clinopyroxenite (type 2) and mafic granulite (type 3) xenoliths. The behavior of compatible and incompatible elements correlates well with MgO as expected for mantle rocks and crystallizing melts. PT estimates yield about 1000-1300ºC at 1.6-1.9 GPa for type 1 xenoliths, 950-1200ºC at 1.6-2.2 GPa and 700->1000 ºC at 0.95-1.3 GPa for type 2 and type 3 xenoliths, respectively. The original ruby formation clearly relates to mafic granulite xenoliths (type 3) which appear to have formed at about 30-50 km depths before picking up and transport onto the surface via basaltic eruption.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

and Phetchabun (figure 1). However, a few main areas have been economically mined and supplied gems to the world market. Sapphire mines were once extensively operated in Kanchanaburi, but most have recently closed down. The Chanthaburi-Trat area has been the most significant source of Thai corundum, and a few small mines are still in operation there. The most famous source of Thai rubies is located in the Bo Rai deposit in the eastern part of Trat Province, close to the Cambodian province of Pailin (figure 1). What became known as "Siamese ruby" was first named from here and adjacent areas. Meanwhile, the main gem mining area for sapphire (yellow, green, and blue, along with golden star and black star sapphires) is the Bang Ka Cha deposit in western Chanthaburi (again, see figure 1). Most gem mines in the central deposits, around Khlung District within Chanthaburi Province, have supplied more sapphire than ruby (Vichit, 1992; Pattamalai, 2015). The focus of this study, the Bo Welu gem field located in the central gem deposits, has been mined for both ruby and sapphire. Corundum from this area is generally heat-treated to enhance its color, especially the red (or purplish red) ruby and the blue sapphire (figure 2), which are in high demand, particularly within Thailand. Although gem mines in this area are not currently in operation, a few artisanal miners can be found working along streams during the rainy season. The rarity of Thai ruby ensures strong demand in the local and international markets and high value. The sapphires, meanwhile, possess a natural greenish blue color that becomes an intense blue after heating. In this study, ruby and sapphire from Bo Welu were investigated to determine their mineral inclu

Previously, different deadlock control strategies for automated manufacturing systems (AMSs) based on Petri Nets with reliable resources have been proposed. However, in real-world applications, resources may be unreliable. Therefore, deadlock control strategies presented in previous research studies are not suitable for such applications. To address this issue, this paper proposes a novel three-step deadlock control strategy for fault detection and treatment of unreliable resource systems. In the first step, a controlled system (deadlock-free) is obtained using the ''Maximum Number of Forbidding First met Bad Markings Problem 1'' (MFFBMP1), which does not consider resource failures. Subsequently, all obtained monitors are merged into a single monitor based on a colored Petri net. The second step addresses deadlocks caused by resource failures in the Petri net model using a common recovery subnet based on colored Petri nets. The recovery subnet is applied to the system obtained in the first step to ensure that the system is reliable. The third step proposes a hybrid approach that combines neural networks with colored Petri nets obtained from the second step, for the detection and treatment of faults. The proposed approach possesses the advantages of modular integration of Petri nets and can also learn neurons and reduce knowledge, similar to neural networks. Therefore, this approach solves the deadlock problem in AMSs and also detects and treats failures. The proposed approach was tested using an example from literature. INDEX TERMS Automated manufacturing system, colored Petri net, deadlocks, fault detection, fault treatment, neural network.

This paper documents the identification and analysis of an unusual variety of common opal colored by chromium—a coloring agent rarely associated with gem opal. The study focuses on translucent and transparent green opal specimens sourced from Peru, which display vibrant green body color without play-of-color. Through spectroscopic techniques and EDXRF, the author confirms trivalent chromium (Cr³⁺) as the chromophore responsible for the green coloration, and that the gems are untreated. Diagnostic absorption bands consistent with chromium were observed in UV-Vis-NIR spectra, while trace element analysis revealed chromium concentrations sufficient to account for the color, distinguishing these opals from more common nickel- or iron-bearing green opals. The discovery expands the known chromatic diversity of transparent to translucent common opal.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Multi-agent Path Finding (MAPF) deals with finding collision-free paths for a set of agents on a graph, where each agent has its origin and destination. Colored MAPF is a generalization of MAPF, where groups of agents are moving, and the set of destination nodes is specified per group rather than per agent. OzoMorph is software providing an intuitive user interface for specifying Colored MAPF problems, solving them by translation to SAT, and finally visualizing the solution either in a computer simulation or by converting the plans to executable instructions for Ozobot Evo robots.

Multi-Agent Path Finding (MAPF) deals with the problem of finding collision-free paths for a set of agents moving in a shared environment. Colored MAPF generalizes MAPF by defining groups of agents that share a set of destination locations. In the paper, we evaluate several approaches to optimally solve colored MAPF problem. We also investigate methods for obtaining lower bounds on optimal solution based on several relaxation techniques.

The problem of Multi-Agent Path Finding (MAPF) is to find paths for a fixed set of agents from their current locations to some desired locations in such a way that the agents do not collide with each other. This problem has been extensively theoretically studied, frequently using an abstract model, that expects uniform durations of moving primitives and perfect synchronization of agents/robots. In this paper we study the question of how the abstract plans generated by existing MAPF algorithms perform in practice when executed on real robots, namely Ozobots. In particular, we use several abstract models of MAPF, including a robust version and a version that assumes turning of a robot, we translate the abstract plans to sequences of motion primitives executable on Ozobots, and we empirically compare the quality of plan execution (real makespan, the number of collisions).

Multi-agent path finding (MAPF) deals with the problem of finding a collision-free path for a set of agents (robots). An abstract model with a graph describing the environment and agents moving between the nodes of the graph has been proposed. This model is widely accepted by the MAPF community and majority of MAPF algorithms rely on this model. In this paper we argue that the model may not be appropriate, when the plans are to be executed on real robots. We provide some preliminary empirical evidence that abstract plans deviate from real plans executed on robots and we compare several variants of abstract models. The paper motivates further research on abstraction of problems with respect to applicability of solutions in practice.

Multi-Agent Path Finding (MAPF) deals with finding collision free paths for a set of agents (robots) moving on a graph. The interest in MAPF in the research community started to increase recently partly due to practical applications in areas such as warehousing and computer games. However, the academic community focuses mostly on solving the abstract version of the problem (moving of agents on the graph) with only a few results on real robots. The presented software MAPF Scenario provides a tool for specifying MAPF problems on grid maps, solving the problems using various abstractions (for example, assuming rotation actions or not), simulating execution of plans, and translating the abstract plans to control programs for small robots Ozobots. The tool is intended as a research platform for evaluating abstract MAPF plans on real robots and as an educational and demonstration tool bridging the areas of artificial intelligence and robotics.

The problem of Multi-Agent Path Finding (MAPF) is to find paths for a fixed set of agents from their current locations to some desired locations in such a way that the agents do not collide with each other. This problem has been extensively theoretically studied, frequently using an abstract model, that expects uniform durations of moving primitives and perfect synchronization of agents/robots. In this paper we study the question of how the abstract plans generated by existing MAPF algorithms perform in practice when executed on real robots, namely Ozobots. In particular, we use several abstract models of MAPF, including a robust version and a version that assumes turning of a robot, we translate the abstract plans to sequences of motion primitives executable on Ozobots, and we empirically compare the quality of plan execution (real makespan, the number of collisions).

Multi-agent path-finding (MAPF) is the problem of finding a plan for moving a set of agents from their initial locations to their goals without collisions. Following this plan, however, may not be possible due to unexpected events that delay some of the agents. In this work, we propose a holistic solution for MAPF that is robust to such unexpected delays. First, we introduce the notion of a k-robust MAPF plan, which is a plan that can be executed even if a limited number (k) of delays occur. We propose sufficient and required conditions for finding a k-robust plan, and show how to convert several MAPF solvers to find such plans. Then, we propose several robust execution policies. An execution policy is a policy for agents executing a MAPF plan. An execution policy is robust if following it guarantees that the agents reach their goals even if they encounter unexpected delays. Several classes of such robust execution policies are proposed and evaluated experimentally. Finally, we pres...

The problem of Multi-Agent Path Finding (MAPF) is to find paths for a fixed set of agents from their current locations to some desired locations in such a way that the agents do not collide with each other. This problem has been extensively theoretically studied, frequently using an abstract model, that expects uniform durations of moving primitives and perfect synchronization of agents/robots. In this paper we study the question of how the abstract plans generated by existing MAPF algorithms perform in practice when executed on real robots, namely Ozobots. In particular, we use several abstract models of MAPF, including a robust version and a version that assumes turning of a robot, we translate the abstract plans to sequences of motion primitives executable on Ozobots, and we empirically compare the quality of plan execution (real makespan, the number of collisions).

The problem of multi-agent path finding (MAPF) is studied in this paper. Solving MAPF optimally is a computationally hard problem and many different optimal algorithms have been designed over the years. These algorithms have good runtimes for some problem instances, while performing badly for other instances. Interestingly, these hard instances are often different across the algorithms. This leads to an idea of combining the strengths of different algorithms in such a way that an input problem instance is split into disjoint subproblems and each subproblem is solved by appropriate algorithm resulting in faster computation than using either of the algorithms for the whole instance. By manual problem decomposition we will empirically show that the above idea is viable. We will also sketch a possible future work on automated problem decomposition.

In this paper, we propose a notion of colored Motzkin paths and establish a bijection between the n-cell standard Young tableaux (SYT) of bounded height and the colored Motzkin paths of length n. This result not only gives a lattice path interpretation of the standard Young tableaux but also reveals an unexpected intrinsic relation between the set of SYTs with at most 2d + 1 rows and the set of SYTs with at most 2d rows.

This paper shows how the study of colored compositions of integers reveals some unexpected and original connection with the Invert operator. The Invert operator becomes an important tool to solve the problem of directly counting the number of colored compositions for any coloration. The interesting consequences arising from this relationship also give an immediate and simple criterion to determine whether a sequence of integers counts the number of some colored compositions. Applications to Catalan and Fibonacci numbers naturally emerge, allowing to clearly answer to some open questions. Moreover, the definition of colored compositions with the "black tie" provides straightforward combinatorial proofs to a new identity involving multinomial coefficients and to a new closed formula for the Invert operator. Finally, colored compositions with the "black tie" give rise to a new combinatorial interpretation for the convolution operator, and to a new and easy method to count the number of parts of colored compositions.