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Hunting strategies and behavioural dynamics of Early Epigravettian hunters-gatherers in Southern Italy. Lithic analysis: reconstruction of reduction sequences connected to projectile weapons at the cave sites of Grotta Paglicci and Grotta della Cala.
No full textLa definizione ed il riconoscimento della fase evoluta dell'Epigravettiano (16000 -15000/14500 Uncal. BP; Palma di Cesnola, 1993) è attualmente oggetto di discussione.
Diversi studiosi non sono d'accordo sulla validità di questa fase e nel corso degli anni sono state avanzate diverse proposte sulla possibilità di integrare questo periodo nelle fasi dell'Epigravettiano Antico o Finale.
La presente ricerca si concentra sullo studio tecno-tipologico di due insiemi litici che in precedenti pubblicazioni sono stati attribuiti tipologicamente all'Epigravettiano Evoluto: gli strati 9c-9c2 di Grotta Paglicci (Rignano Garganico, FG) e lo strato O di Grotta della Cala (Marina di Camerota, SA). Entrambi i siti si trovano in Italia meridionale e conservano importanti sequenze stratigrafiche del Paleolitico superiore. Questo lavoro si concentra in particolare sull’esame delle armature litiche, combinando lo studio tecnologico con l'analisi delle tracce d’uso, condotta con un approccio a basso ingrandimento.
I suddetti insiemi evidenziano caratteristiche riconducibili all’Epigravettiano Antico, in termini di struttura tecno-economica della produzione litica. Sono state infatti individuate caratteristiche associate a un modello basato sul personal gear: la circolazione di grandi lame sotto forma di strumenti che sembrano aver avuto una lunga storia, spesso utilizzate, in un secondo momento, come nuclei per la produzione di lamelle; uno schema produttivo specificamente dedicato alla produzione di lame; produzioni autonome lamellari. Esistono differenze tra i due insiemi litici; a Grotta Paglicci è ben attestata la tecnica della percussione diretta con il percussore in pietra tenera, in contrapposizione alla percussione bipolare su incudine che caratterizza l'insieme di Grotta della Cala. Inoltre, in quest'ultimo sito è documentata la produzione di schegge allungate.
In entrambe le industrie la presenza di armature con tracce riconducibili ad un loro uso in campo venatorio come proiettili è documentata dalla presenza di punte a dorso a Grotta Paglicci e Grotta della Cala e di punte a cran a Grotta della Cala.
Alla luce dei risultati ottenuti nel presente lavoro e sulla base dei confronti con altri insiemi litici epigravettiani oggetto di studi tecnologici recenti, si propone per le industrie degli strati 9c-9c2 di Grotta Paglicci e dello strato O di Grotta della Cala un’attribuzione ad una fase specifica all'interno dello sviluppo dell'Epigravettiano antico, anche se la seriazione interna di quest'ultimo periodo rimane da stabilire con precisione.Defining and recognising the so-called evolved phase of the Epigravettian (c. 16000 to 15000/14500 Uncal. BP; Palma di Cesnola, 1993) is still a problematic issue. Several scholars disagree with the validity of this label, and, over the years, different proposals have been put forward regarding the integration of this period into the Early or Late Epigravettian phases. In light of this debate, the present research focuses on the techno-typological study of two lithic assemblages that had been typologically attributed to the Evolved Epigravettian in previous publications: layers 9c-9c2 of Grotta Paglicci (Rignano Garganico, FG) and layer O of Grotta della Cala (Marina di Camerota, SA). Both sites are major Upper Palaeolithic stratigraphic sequences from southern Italy. This work notably focuses on the study of lithic armatures, combining technological study with the use-wear analysis, carried out with a low-power approach.
Both assemblages show Early Epigravettian patterns in terms of techno-economic structuration of the lithic production. Indeed, we identified features associated with a personal gear-based model: the circulation of large blades in the form of tools that appear to have had a long life cycle, often ending up as cores for the production of bladelets; a production scheme specifically dedicated to the production of blades; and the appearance of autonomous bladelet productions. There are differences between the two lithic assemblages; the direct percussion technique with soft hammerstone is well attested at Grotta Paglicci, as opposed to the bipolar percussion on anvil that characterises the assemblage from Grotta della Cala. Furthermore, the production of elongated flakes is documented at the latter site.
In both assemblages the presence of armatures with traces of hunting activity is documented by the occurrence of backed points from Grotta Paglicci and Grotta della Cala and shouldered points from Grotta della Cala.
In the light of our results, and in comparison with recent research on Epigravettian assemblages from a technological perspective, it could be proposed that the Evolved Epigravettian should be considered as a specific step within the development of the Early Epigravettian, although the internal seriation of this last period remains to be precisely established
A comparison between lean and visibility approach in supply chain planning
Full text linkNowadays, competition increases more and more in the market and it is moved from firm vs firm to supply chain vs supply chain. Therefore, supply chains (SC) are always looking to improve their efficiency to excel in the market. In order to do that, SC managers pay much attention to the coordination among SC members. SC planning allows the coordination among the SC players. In the literature, many SC planning approaches have been developed and analyzed, but up to now, the debate on which is the best approach is an open issue. On the other hand, lean approach is becoming more and more popular among SC managers. Both practitioners and academics have recognized the importance of Lean approach for single firm efficiency. This paper aim at evaluating the impact of Lean approach implementation in supply chain planning tasks. It provides an in-depth analysis of Lean SC planning policy impact on SC performances and compare it with traditional EOQ and Visibility policies. The influence of SC planning policies and of external parameters is assessed in a DES simulation study. The simulation model tests a multi-product three-echelon supply chain. Lean "pull" principle is developed through Kanban system implementation and Lean "create the flow" principle is developed through setup time and batch size reductions. The simulation study analyses inventory level, transportation performance and service level performances. According to simulation outputs a total SC logistic costs have been evaluated for each scenario. The results provide new insights suggesting that Lean supply chain planning policy gives competitive advantages. The results have important consequences for implementation of Lean concepts in practice in SC planning tasks
Simulation of Lean Principles Impact in a Multi-Product Supply Chain
Full text linkThe market competition is moving from the single firm to the whole supply chain because of increasing competition and growing need for operational efficiencies and customer orientation. Supply chain management allows companies to look beyond their organizational boundaries to develop and leverage resources and capabilities of their supply chain partners. This creates competitive advantages in the marketplace and because of this SCM has acquired strategic importance. Lean Approach is a management strategy that focuses on reducing every type of waste present in an organization. This approach is becoming more and more popular among supply chain managers. The supply chain application of lean approach is not frequent. In particular, it is not well studied which are the impacts of lean approach principles in a supply chain context. In literature there are only few studies aimed at understanding the qualitative impact of the lean approach in supply chains. Therefore, the goal of this research work is to study the impacts of lean principles implementation along a supply chain. To achieve this, a simulation model of a threeechelon multi-product supply chain has been built. Kanban system (and several priority policies) and setup time reduction degrees are implemented in the lean-configured supply chain to apply pull and lot-sizing decrease principles respectively. To evaluate the benefits of lean approach, lean supply chain is compared with an EOQ-configured supply chain. The simulation results show that Kanban system and setup-time reduction improve inventory stock level. They also show that logistics efforts are affected to lean implementation degree. The paper concludes describing performances of lean supply chain in different contexts
Lean supply chain planning: A performance evaluation through simulation
Full text linkNowadays companies look more and more for improving their efficiency to excel in the market. At the same time, the competition has moved from firm level to whole supply chain level. Supply chain are very complex systems and lacks of coordination among their members leads to inefficiency. Supply chain planning task is to improve coordination among supply chain members. Which is the best planning solution to improve efficiency is an open issue. On the other hand, Lean approach is becoming more and more popular among managers. Lean approach is recognize as efficiency engine for production systems, but effects of Lean implementation out of single firm boundaries is not clear. This paper aims at providing a theoretical and practical starting point for Lean implementation in supply chain planning issue. To reach it, a DES simulation model of a three-echelon and multi-product supply chain has been set. Lean management is a very broad topic and this paper focuses on two principles of "pull" and "create the flow". Kanban system and setup-time and batch-size reductions are implemented in the lean-configured supply chain to apply "pull" and "create the flow" respectively. Lean principles implementations have been analyzed and compared with other supply chain planning policies: EOQ and information sharing (Visibility). Supported by the simulation study, this paper points Lean supply chain planning is a competitive planning policies to increase efficiency
Dissimilar Resistance Spot Welding of Q&P and TWIP Steel Sheets
No full textDissimilar resistance spot welding of TWinning Induced Plasticity (TWIP) and Quenching and Partitioning (Q&P) steel grades has been investigated by evaluating the effects of clamping force, welding current, and welding time on the microstructure, shear tension strength, and fracture of welded samples. The spot welding of TWIP and Q&P steels promotes the occurrence of an asymmetrical weld nugget with a greater dilution of TWIP steel because of its lower melting temperature and thermal conductivity. As a result, weld nuggets exhibit an austenitic microstructure. TWIP steel undergoes a grain coarsening in the HAZ, whereas Q&P steel undergoes some phase transformations. Welded samples tend to exhibit higher shear tension strength as they are joined at the highest welding current, even though an improper clamping force can promote excessive metal expulsion, thereby reducing the mechanical strength of the welded joints. Shear tension welded samples failed through interfacial fracture with partial thickness fracture mode for a low welding current, while partial thickness with button pull fractures were observed when a high welding current was used. The weld spots predominantly failed atthe TWIP side. However, as TWIP steel can work harden significantly in the more resistant welded joints, the failures occur, instead, at the Q&P side
Investigation on Resistance Spot Welding of TWIP Steel Sheets
No full textA widespread usage of new advanced high strength TWIP steels in the automotive industry is conditional on proper assembly operations by welding. Therefore, the effects of the main important process parameters on the mechanical and microstructural properties of resistance spot welded TWIP sheets are examined here. The welding parameters used were welding current, clamping force, and welding time. An L-9(33) orthogonally array was used to design the experimental tests. The mechanical response of the welded joints was assessed by tensile shear tests and Vickers microhardness measurements. The effect of the welding parameters on the fracture mode of the tensile shear specimens was also investigated. Some combinations of the welding process parameters guaranteed acceptable tensile shear strengths for the automotive industry. The tensile shear samples mainly failed by interfacial fracture mode, while partial thickness with pull out fractures were observed in the samples welded with the highest welding current and clamping force. Improper clamping force and welding current promoted excessive metal expulsions and, in turn, the formation of welding defects in the weld spot
PREFACE 6th European Lean Educator Conference, ELEC 2019; Milan; Italy; 11 November 2019 through 13 November 2019
No full textCollaboration between university and industry is essential in today’s
changing environment, where limited resources must be used by as many users as
possible in an efficient manner. At the University of Valladolid we have a Lean School
equipped in collaboration with Renault-Nissan Consulting where training is given to
students, workers and professionals: initially in Lean Manufacturing, but with a rapid
evolution and improvement towards other paradigms, also integrating the concept
of Circular Economy. The main contribution of this paper is the presentation of a
training in a learning factory, combining lean manufacturing and circular economy.
The assimilation of knowledge by the students with this training process based on
role play and simulation of a real process are much higher than those obtained with
traditional methods. Furthermore, the new training contributes to the reduction of economic and environmental impacts, mainly: reduction of inventory, raw materials,
solid wastes, energy and motions
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