Blade Production Research Articles

L’Atelier aurignacien découvert à Bușag (Nord-Ouest de la Roumanie). Données préliminaires

Rescue excavations carried out on the Bușag Hill in 2019 (the Palaeolithic site had been identified and excavated by Maria Bitiri in the 1960s and 1970s) allowed for new stratigraphic observations required by a future re-evaluation of the chronology. While we still await for the OSL results on the samples collected from trench II and the microscopic analysis of raw materials, the present paper presents preliminary observations on the lithic material from the Aurignacian workshop uncovered in soundings V and VI, level D : a homogenous assemblage ; two operational chains oriented towards blade production, predominant blade production ; possible presence of flake production ; predominant hard percussion, careful debitage, a certain massiveness of the lithic assemblage ; raw materials brought to the site in their natural form or with little modification.

Macroscopic process simulation of surface and profile grinding processes estimating forces for the production of turbine blades

In aerospace industry surface and profile grinding processes are widely used for the manufacturing of turbine blades. Maximizing the productivity is a key factor for industry, which can be achieved by reducing the number of cuts necessary in order to remove the remaining millimeters of stock material after casting. This leads to high depth of cut values and, therefore, considerably high process forces. Turbine blades are highly flexible workpieces resulting in process induced deflections. In order to avoid mechanical damages of the workpiece during the process, a macroscopic grinding simulation is used, which is presented in this paper. For this process simulation a coupled multiphysics FE model was created using the software COMSOL Multiphysics. First, the material removal was evaluated using the deformed geometry module of the software. Based on the current material removal the process forces were calculated using an experimentally calibrated grinding force model. The forces were subsequently applied onto the grinding area allowing for a calculation of the resulting stresses and deflections. Further, the simulation was extended for profile grinding processes using an inclined grinding wheel and a fir tree profile of a turbine blade. The simulated forces were validated based on experimentally conducted grinding processes.

Местонахождение Урочище Балчикова V – новый объект раннего верхнего палеолита Алтая

A survey was carried out by a team from IAET SB RAS in the area of Urochiche Balchikova V( Balchikov locality V) situated in northwestern Altai in 2021. This article presents the preliminary results of studies at this site. The the site is located is in the vicinity of the Sentelek village in the Charyshskiy District of Altai Krai. In geomorphological terms, this area is a cirque formed by an extension of the Sentelek River valley framed by mountains. The exposed artifacts are confined to a promontory on the left bank of the Sentelek River representing the diluvium train of Voskudarnaya Teplukha Mountain. P.I. Shulga found the first stone tools at this site in 1991. The 2021 collection counts 8 artifacts. The most representative part of the exposed complex consists of artifacts associated with primary reduction: a sub-prismatic double platform blade core of the bidirectional reduction pattern with one flaking surface; a preform of the double platform core and technical spalls. The tool kit is represented by a scraper-shaped tool made on a silicite tablet. The few artifacts collected from the surface are technologically-diagnostic. Their morphology and characteristic technological features suggest attribution of the assemblage to the early stages of the Upper Paleolithic. The flaking technique aimed at production of large thin blades under the bidirectional prismatic flaking strategy is characteristic of the industries of the Initial and Early Upper Paleolithic of North and Central Asia. The closest parallels to these materials are in lithic assemblages of the Early Upper Paleolithic of Altai (Kara-Bom, UP complexes 1 and 2, Ust-Karakol-1, layers 8-11), Mongolia (Tolbor-4, horizons 5 and 6) and Eastern Kazakhstan (Ushbulak, layers 6 and 7).

Возникновение микролитического производства в Монголии: исследовательская терминология и хроностратиграфическая позиция индустрий в верхнем палеолите восточной и южной части Азии

Territory of Mongolia is situated in the center of Asia, a crossroad of the potential migration routes, that connect different Eurasian macroregions. Here an example of earliest appearance and longterm existence of small blade and microblade production has been found. Beyond that, the industries, that appeared within limited area of the Middle Selenga Basin in the late MIS3 — early MIS2, contained the earliest for Northern and Central Asia geometric and non-geometric microliths. They have been found in the sediments of Kharganyn Gol 5 and Tolbor-4, — 16 and –21. They end up in LGM — post- LGM which cause depopulation in the region and following changes in the human groups, occupying this territory. An understanding of the character, causes and specifics of such early appearance of the microblade and bladelet production, and especially geometric microliths, impose the arrangement and definition of the terminology, associated with microlithic assemblages in Asia. This is due to the fact that in the archaeological definitions of both processes and the desired forms of artifacts associated with the production and use of microliths, there are significant discrepancies that complicate the understanding of the described phenomena. The article provides an overview of the research terminology of microlithization processes, and also determines the position of the microlithic complexes of Mongolia in the Upper Paleolithic system of the eastern part of Asia. Keywords: Mongolia, East Asia, Upper Paleolithic, lithic industries, microlithic technology

Dawn of a new day: The role of children in the assimilation of new technologies throughout the Lower Paleolithic

In this paper, I contend that children had a unique position in prehistoric social systems, functioning as primary assimilators of new technologies. Their role is especially crucial at significant turning points in history, due to a number of childhood-cognitive mechanisms that are activated in learning and playing while engaging in innovative activity. I suggest that these mechanisms developed as part of an evolutionary process that has enabled humans to better adapt to change and prosper. This line of thinking is demonstrated through a synthesis of evolutionary, cognitive-psychological models and a case study from the archaeological record of the Levantine late Lower Paleolithic. In this time, humans developed a set of creative innovations which had to be learned and assimilated, such as the innovative production of blades. I argue that these cultural changes were successfully assimilated by groups inhabiting the Levant due to the enhancement of well-established learning mechanisms, in which children played a significant role. This role might have given them a unique status in their group – as preserving old traditions practiced by their ancestors but also as active agents, part of a collective group effort of tackling present and future challenges.

Tiny Defect Detection in High-Resolution Aero-Engine Blade Images via a Coarse-to-Fine Framework

This article studies the problem of aero-engine blade surface defect detection in large images. The effective method for aero-engine blade surface inspection for this real application is currently lacking since most defects are relatively small. Therefore, the task of aero-engine blade surface defect detection is mainly implemented by experienced operators, which is subjective and time-consuming. Moreover, it is hard to fit the requirements of higher accuracy and efficiency manually. Therefore, an effective and efficient method for aero-engine blade surface defect detection is demanded. To achieve this, we propose a vision-based framework in this study to detect defects in a coarse-to-fine manner. First, the captured raw images are with a high resolution of $2448\times 2048$ to ensure the accuracy of defect detection. The raw images are then cropped into smaller regions and fed into our deep convolution neural network (DCNN) to learn features with high representation. Next, the coarse classifier module is proposed to filter most background regions out. Finally, the defects are located and classified by a fine detector module in the defective images, which are selected by the coarse classifier module. Instead of directly applying a detector, our coarse-to-fine framework can effectively save computation and improve accuracy. In addition, the coarse-to-fine framework can be trained in an end-to-end manner. Compared with classical methods for object detection, our method also achieves state-of-the-art performance for aero-engine blade surface defect detection in terms of accuracy and efficiency. Furthermore, our framework has been applied for practical application in many aero-engine blade production lines.

О возрасте и месте верхнепалеолитического местонахождения Весна в палеолите юга Средней Сибири

In the archaeology, the problem of the transition from the Middle to the Upper Paleolithic is considered as one of the key problems. This article presents the study results of the Vesna site (initial stage of the Upper Paleolithic), located in the south of Middle Siberia on the territory of Irkutsk amphitheater in the lower reaches of the Kuda river. Lithic industry of the Vesna site is based on the use of platy mudstone and is characterized by the blade production of within the of plain longitudinal and by-longitudinal knapping. The tool set of the assemblage contains both Middle and Upper Paleolithic types of tools. The tools on the blades are predominant in this assemblage. Radiocarbon data obtained in different laboratories using the AMS method show the dates 46,700±3400, 43,300±1700, and 40,600±1300 BP. They indicate the Early and Middle Karginian age of this archaeological complex. New finds obtained in 2018 expand our understanding of the industry of Vesna site. Among the finds, tools with a flattened base stand out, which indicates the possible use by the inhabitants of the site of composite tools and, possibly, weapons. In general, the Vesna assemblage finds its analogues with industries from the Arembovskii and the Aksenov sites, also situated in the Irkutsk amphitheater, which are based on similar mudstone raw materials. Their age was previously determined by the final of MIS 3, with certain reservations. Our studies indicate the earliest time of the appearance of the carriers of these industries on the territory of the Irkutsk amphitheater and the Southern Angara region. This reasonably raises the question of the time of their existence in this area. Based on the totality of data, it can be argued that, in general, in the south of Middle Siberia, the industry of the Vesna complex shows the greatest similarity with the materials of the reference Upper Paleolithic site in region – Makarovo 4, the age of which, based on the analysis of stratigraphy (by the author of the excavations M. P. Aksenov), was estimated within the first half of MIS 3. The issue of the timeframe of the appearance and spread of Upper Paleolithic industries in Eurasia is in this case a general issue. This highlights the importance of its regional aspects, one of which is discussed in this article.

Леваллуазская технология в Китае

Levallois technology dispersal is associated with several events of human habitation of the Asian region. Emergence of the Levallois technology in China precedes or coincides in time with the penetration of Initial Upper Paleolithic laminar industries into this region. All known Paleolithic localities, the assemblages of which include the Levallois component, are located in the border or adjacent zones in the modern China. The authors examine all these complexes and make an assumption about the nature of the Levallois technology introduced from the territories of the Russian Altai, Mongolia and India. Such complexes are dated to the terminal Middle Paleolithic and the initial Upper Paleolithic. In general, this period in China is characterized by a flake industry, often made on poor quality stone raw materials. In this region, three Levallois techniques are distinguished: preferential centripetal and parallel for the production of flakes and convergent unidirectional for the production of points. The convergent bidirectional reduction aimed at point production is not recorded in assemblages originating from the territory of China. In Mongolia, this technique is recorded along with the bidirectional parallel laminar technology in the Initial Upper Paleolithic industries, while in China both Levallois point and blade production techniques were unidirectional. The authors conclude that for most of the Paleolithic sites in China, the Levallois technology is an intrusive element that emerged along with the large blade industry. The exception is the Middle Paleolithic flake industry originating from the Jinsitai Cave, which is similar in its characteristics to the materials from the Denisova Cave. The composition of Xinjiang industries indicates that this territory was a kind of region where cultural complexes spread together with the bearers of these traditions along the Altai Mountains.

Sealing with Stone: Assessing an Assemblage of Lithic Debitage from a Funerary Context at the Lowland Maya City of Caracol, Belize

Excavators working in a ceremonial plaza group in the Classic period Lowland Maya city of Caracol, Belize, encountered thousands of pieces of chert and obsidian scattered above a royal tomb. A recent analysis of the chert from this context confirms that the assemblage included pieces from each stage of reduction in the production of blades. Taken together, the quantity of both chert and obsidian makes it the largest reported collection of lithic debitage found at the site and provides insight into the techniques of lithic crafters at Caracol. In this article, we consider the sequence of actions involved in the burial of a high-ranking individual and suggest that the layering of flaked stone above the tomb is reminiscent of other reported above-tomb contexts in the Maya Lowlands. Further, a technological analysis of this collection produced results similar to analyses of assemblages typically found in crafting-intensive residential groups. This finding suggests that lithic crafters throughout the city of Caracol donated flaked stone material for funerary events, providing a protective layer and sealing the grave below.

Lithic technological organization of the “Elmenteitan” early herders in southern Kenya: Implications for mobility, exchange, and climatic resilience

Mobile pastoralism is the earliest form of food production to develop in Africa, and for the past 5000 years has remained one of the most important subsistence strategies for people across the continent. Despite its importance, the technological infrastructures that facilitated the successful spread of stone-tool–using pastoralists through environmentally heterogenous and climatically unpredictable regions remain poorly understood. This study provides comprehensive analyses of the lithic technological organization of early herders in southern Kenya responsible for the distinct “Elmenteitan” material traditions. Quantitative data on blade production strategies from thirteen Elmenteitan sites demonstrate that this group represents the emergence of new technological strategies based on participation in long-distance obsidian exchange networks, and flexible and versatile blade blank production. Elmenteitan lithic technological patterns are interpreted in terms of preparation for different configurations of local and regional mobility, which helped early herders manage environmental unpredictability in eastern Africa. These data provide a foundation for future study of the role of lithic technologies in pastoralist economies and contribute a case study from mobile food-producer contexts to global debates on the organization of stone tool economies.

Производство пластин в каменной индустрии верхнепалеолитического местонахождения Три Скалы (Западное Забайкалье)

In 2015 the investigations on a new multi-layered archaeological site named Tri Skaly started. The analysis of the stone artifacts showed that lithological layers 3–5 contains the homogenous materials‑ typical to the early stage of the Upper Palaeolithic in the Western Transbaikalia. Materials under consideration include such important component of the primary knapping as blades and cores used for blade production. The first results of the investigations showed that the industry of the Tri Skaly site is among the industries combined into Tolbaga Palaeolithic culture which is characterized by the prevailing of the making tools from stone blades. This article is devoted to the consideration of the blade component in the stone industry of the 3–5 lithological layers of the Tri Skaly site which is situated in the central part of the Selenga Highlands. Based on the studies carried out, it has been established that the typology and morphology of the main groups of stone artifacts of the Tri Skaly in most parameters are similar to the materials of such sites of the early Upper Paleolithic of Western Transbaikalia as Tolbaga and the Eastern Podzvonkoy complex. A significantly smaller number of blades of the Tri Skaly is noted in comparison with the ones from Tolbaga and the Eastern Podzvonka complex, converted into tools or used as tools without preliminary retouching. Presumably, this may be due to the specifics of the excavated area, where primary knapping was mainly carried out.

Design of variable withdrawal rate for superalloy single-crystal blade fabrication

Stray grains bring great challenges to the production of superalloy single-crystal blades using the Bridgman method. The height difference between the liquidus isotherms in the airfoil and platform, which is induced by the difference between liquidus isotherm advancing velocity and withdrawal rate, provides undercooling for the nucleation and the growth of stray grains. The height range of liquidus isotherm is used for the first time to describe the asymmetric distribution of temperature and radiation, and to estimate the probability of stray grain formation. A real-time adjustment of withdrawal rate method is proposed to design the withdrawal rate-time curve aiming to fabricate superalloy single-crystal blades with complex geometry. The obtained withdrawal rate curve is then validated by numerical simulation and hence applied to the fabrication of single-crystal blades. The simulation results show that with obtained withdrawal rate curve the distribution of radiation and temperature are significantly improved and the undercooling in the platform is largely reduced. The observed macrostructure in the experiments proves that the stray grains in the platform can be avoided through the designed withdrawal rate curve. The proposed method for designing withdrawal rate can provide a reliable strategy for the research and manufacture of stray-grain-free single-crystal blades.

Study of the properties of large-sized blanks of turbine blades made of 15Kh11MF-Sh steel depending on the method of obtaining the initial metal

We consider the manufacturing process of forgings for turbine blades of extra-large dimensions (length >2 m) from electroslag remelting steel 15H11MF-Sh. With an increase of the workpiece dimensions (weight >450 kg), we face the problem of choosing the technology for obtaining the original billet. The production technology is known to affect the structure of the material and, as a consequence, the final properties of the product. We present the results of studying the influence of the method of obtaining the original metal blanks (hot-rolled steel bars and forged billets) on the properties of large-sized forgings of turbine blades. The mechanical characteristics, microstructure properties, chemical composition and content of δ -ferrite were determined by examining the initial samples of long products and forged rods. It is shown that billet in the forged state exhibit higher strength characteristics. However, after the stamping process, the properties of the blades equalize, i.e., after stamping and heat treatment, the same structure is formed, regardless of the method of obtaining the original workpiece. The results obtained can be used in the serial production of large-sized turbine blades of a new profile.

High-Temperature Salt Corrosion of a Heat-Resistant Nickel Alloy

We develop a heat-resistant corrosion-resistant alloy based on nickel and alloyed with rhenium and tantalum. This alloy is intended for the production of blades for a new generation of power-generating and ship gas-turbine engines. It is shown that the introduction of rhenium (3.7–4.3 wt.%) and tantalum (2.5–4.3 wt.%) into the composition of the experimental alloy increases the high-temperature corrosion resistance of the material (narrows the frontal zone of corrosion damage) under the influence of gas-salt media formed under the combined action of the combustion products of fuel and seawater salts.

Production of Andropogon gayanus cv. Planaltina dry matter estimated through NDVI

Pasture management studies seldom use remote sensing, especially for Andropogon gayanus cv. Planaltina. This work aimed to investigate whether a single-chip digital camera converted into multispectral equipment could measure and perceive differences in the normalized difference vegetation index (NDVI) in Andropogon gayanus cv. Planaltina grass subjected to different doses of nitrogen. In a greenhouse with a randomized block design, the research team subjected the cultivar to 5 different doses of nitrogen (treatments), with four replications. The group compared the NDVI measurements of canopies carried out with a GreenSeeker® HCS-100 active optical sensor and a Canon PowerShot A495 single-chip camera that was converted into a multispectral device by replacing the glass filter that blocks the passage of the infrared by a filter that allows the passage of the red and near infrared wavelengths. Both measurements were correlated with nitrogen doses, stem and leaf blades dry matter and dead material production, and cultivar height. The study concluded that the multispectral camera, as well as the active optical sensor, measured the NDVI and noticed differences in the production of stem, leaf blades and dead material dry matter, and Andropogon gayanus cv. Planaltina plant height when subjected to different doses of nitrogen.

Blade materials selection influence on sustainability: a case study through LCA

In this study, the environmental influence that blade materials have on the entire wind turbine lifecycle is considered. In order to quantify and compare the effects that a specific material’s choice has with respect to one another, Life-Cycle Assessment (LCA) tools are used. Specific focus is addressed on aspects related to the wind turbine rotor-blade and how that affects the whole turbine. The blade lifecycle is divided into five main stages: (1) raw material sourcing, (2) blade manufacturing, (3) blade installation, (4) Operation and Maintenance (O&M) and (5) End-of-Life (EoL). Materials sourcing is found responsible for the largest contribution in Green House Gas (GHG) emission in the turbine and blade lifecycle. Particularly, a case study on a representative blade production in Siemens Gamesa Renewable Energy (SGRE) is disclosed and compared to a hypothetical blade production where a recyclable resin system is being used. The lifecycle assessment shows a 28% reduced amount of GHG emissions when the recyclable resin system is employed. By employing such resin system most of blade materials could be separated and re-used at the blade EoL, enabling a 90% blade recycling rate. An even greater advantage of achieving blade circularity is therefore envisioned.

Modelling of chemical shrinkage evolution with curing degree of a filled epoxy adhesive

An epoxy adhesive system, commonly used in wind turbine blade manufacturing, is experimentally investigated with respect to its chemical shrinkage behavior to show the shrinkage evolution within rotor blade production related process conditions. Therefore, a new test configuration is set up to record the resulting chemical shrinkage of the adhesive at cross-linking temperatures ranging from 20°C to 90°C. The respective conversion evolution is simulated under several temperature conditions through a curing kinetics model. This is generated with state of the art formulations, implementing test results from a differential scanning calorimeter (DSC). Moreover, the transformation of the curing degree to the corresponding glass transition temperature (Tg ) is performed through an experimentally based Di-Benedetto curve-fitting. By the combination of curing kinetics and chemical shrinkage test data, a model for the temperature and conversion dependant chemical shrinkage evolution during cure is developed. This is applied to a realistic curing cycle for adhesive materials in rotor blade production.

Geometrical effect on macrosegregation formation during unidirectional solidification of Al–Si alloy

Abstract In the production of single-crystal turbine blades for use in aircraft engines with unidirectional solidification techniques, it is confirmed that the casting geometry had great influence on the formation of macrosegregation or spurious/stray crystals. In this study, a two-phase solidification model is used to investigate the geometrical effect on the unidirectional solidification of Al–7.0 wt.% Si alloy. The study is based on the experiment of Ghods et al. (2016a) , in which the diameter of the sample is changed between ϕ9.5 and ϕ3.2 mm along the solidification direction to highlight the geometrical effect. The first part of the investigation is to verify the numerical model by ‘reproducing’ the experimentally obtained macrosegregation and phase distribution in an as-cast sample. The second part is to explore the macrosegregation mechanism. It is found that the main geometrical effect is the modification of the bulk and the interdendritic melt flow during solidification. Different flow patterns are found in different locations, e.g. below or above the cross-section contraction; however, details of the macrosegregation formation can be explained by a scalar product of two vectors, i.e. the flow velocity and the concentration gradient of the melt. Based on the positive/negative value of the scalar product, i.e. the flow direction in comparison with the direction of the concentration gradient, it is possible to determine where a negative/positive segregation will occur. The above scalar product is also found valid for analysing the possible formation of spurious/stray crystals, and it is numerically demonstrated that the cross-section expansion in casting geometry leads to high risk of spurious/stray crystals.

Microstructure refinement of single crystal Ni-based superalloy by improvement of thermal radiation shielding in the industrial-scale Bridgman solidification process

Refinement of dendritic microstructure in CMSX-4 Ni-based single crystal casting blade, manufactured using standard adjusted (ARB) or novel inner radiation baffles (IRBs) in the industrial-scale Bridgman solidification process, was investigated in the paper. Temperature gradient in the blade was mainly controlled by baffle geometry and by changing local solidification rate along casting height. Results showed that the use of relatively simple modification of mold, by introducing IRBs, resulted in increase of temperature gradient and noticeable refinement of dendritic microstructure. Temperature gradient in airfoil of blade increased by 30 and 95%, while primary dendrite arm spacing (PDAS) was favorably reduced by 7.8 and 21% for ARB and IRBs, respectively, compared with standard ring radiation baffle. The use of IRBs and ARB resulted in increase of tendency to form sliver defect in airfoil and low angle grain boundary in blade platforms. However, length of freckle chains decreased at root edge of blades when IRBs were used. New design and a proposal of the implementation of IRBs technique for the production of large IGT blades using Bridgman method were also discussed in this article.

Human adaptive responses to climate and environmental change during the Gravettian of Lapa do Picareiro (Portugal)

On the Iberian Peninsula, abrupt climate shifts during the Late Pleistocene impacted human and natural systems. Our knowledge of human adaptive responses to these climatic perturbations has improved in recent years with the development of new radiocarbon techniques that have increased the temporal resolution of cultural chronologies. At the same time, new high-resolution paleoclimatic records from Greenland ice cores, deep-sea sediment cores, speleothems, and microfaunal assemblages have permitted detailed paleoenvironmental reconstructions. Combined with the archaeological record of culture change, these data sets allow for a better understanding of the nature of human socio-ecological systems during the Late Pleistocene. Here we present new data on the Gravettian occupations at Lapa do Picareiro, a cave site in Portugal with a long continuous stratigraphic sequence spanning MIS 3 and 2. The ongoing excavation of Lapa do Picareiro has revealed at least three Gravettian levels with very different patterns of raw material use and technological reduction. The Early Gravettian levels contain a quartzite flake assemblage with several refitting clusters and a small chert assemblage with nosed endscrapers and bladelet technology. The Late or Terminal Gravettian level contains carinated endscraper/core-bladelet technology, mainly quartz, with chert blade production, and a few bone tools. The faunal assemblages also have a different character. Both contain a similar range of medium and large ungulates but the earlier Gravettian has a much richer and more diverse assemblage of small animals. These combined archaeological data sets provide a new perspective on Gravettian human adaptations in response to climate shifts, especially Heinrich Event 3 and Greenland Interstadials 4 and 3.