scholarly journals Metallographic investigation of Early Bronze Age armbands from Western Switzerland (ca. 2200–1500 BC): new highlights about early manufacturing processes

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
Paolo Piccardo ◽  
Justine Vernet ◽  
Guillaume Voland ◽  
Giorgia Ghiara
Keyword(s):  
Bronze Age ◽  
Manufacturing Process ◽  
Copper Matrix ◽  
Thermal Treatments ◽  
Deformation Degree ◽  
Minor Elements ◽  
Western Area ◽  
Metal Composition ◽  
Copper Based Alloy ◽  
Selection Of

Abstract The Valaisan-type armband (a specific type of bracelet) is a typical metallurgical production from the western area of Switzerland belonging to the classic phase of the Aare-Rhone group (BzA2a, ca. 2000–1800 BC). This investigation aims to (i) characterize the metal composition, (ii) reconstruct the thermomechanical treatments applied during the manufacturing process, and (iii) gather information on the possible exploitation of the local ores coupling metallography and chemical analysis. The results show that each armband is manufactured from a hammered sheet of copper-based alloy, containing either tin (up to 3.0 wt.%) or a combination of antimony, nickel, and silver. In several cases, it is assumed that minor elements are already part of the original ore, suggesting a conscious selection of copper veins. In other armbands, a direct addition of cassiterite (SnO2) to the copper matrix is hypothesized based on the material composition and features of the inclusions. Microstructural features are coherent with a procedure that combines mechanical deformation (with a total deformation degree between 70 and 76%), annealing, and quenching, coherently with more recent productions (Late Bronze Age). The analysis of inclusions, rarely performed during metallographic investigations, provides precious evidences on thermal treatments applied during the manufacturing process and shows that annealing was carried out at low temperatures.

MICROSTRUCTURE AND PROPERTIES OF SiC PARTICLES REINFORCED COPPER BASED ALLOY COMPOSITE

2013 ◽  
Vol 27 (19) ◽  
pp. 1341025 ◽  
Author(s):  
YU HONG ◽  
XIAOLI CHEN ◽  
WENFANG WANG ◽  
YUCHENG WU
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Relative Density ◽  
Volume Fraction ◽  
Copper Matrix ◽  
Matrix Composites ◽  
Wear Properties ◽  
Sic Particles ◽  
Copper Based Alloy

Copper-matrix composites reinforced with SiC particles are prepared by mechanical alloying. The microstructure characteristics, relative density, hardness, tensile strength, electrical conductivity, thermal conductivity and wear properties of the composites are investigated in this paper. The results indicate that the relative density, macro-hardness and mechanical properties of composites are improved by modifying the surface of SiC particles with Cu and Ni . The electrical conductivity and thermal conductivity of composites, however, are not obviously improved. For a given volume fraction of SiC , the Cu / SiC ( Ni ) has higher mechanical properties than Cu / SiC ( Cu ). The wear resistance of the composites are improved by the addition of SiC . The composites with optimized interface have lower wear rate.

Phase selection of titanium boride in copper matrix composites during solidification

2016 ◽  
Vol 52 (5) ◽  
pp. 2957-2963 ◽  
Author(s):  
Yihui Jiang ◽  
Dan Li ◽  
Shuhua Liang ◽  
Juntao Zou ◽  
Feng Liu
Keyword(s):  
Titanium Boride ◽  
Copper Matrix ◽  
Matrix Composites ◽  
Phase Selection ◽  
Copper Matrix Composites ◽  
Selection Of

scholarly journals KOMPETENSI PETERNAK SAPI POTONG PERANAKAN ONGOLE DALAM PEMBUATAN KOMPOS (STUDI KASUS PADA KELOMPOK TERNAK MEKAR KECAMATAN DAGANGAN KABUPATEN MADIUN)

2018 ◽  
Vol 10 (3) ◽  
pp. 1
Author(s):  
Deha Purwoko ◽  
Bekti Nur Utami
Keyword(s):  
Manufacturing Process ◽  
Research Method ◽  
Organic Content ◽  
Compost Quality ◽  
Preparation Stage ◽  
Before And After ◽  
Descriptive Approach ◽  
Quantitative Descriptive ◽  
Selection Of

This research aims to describe the level of competence of farmers in composting, and to draft extension and try out the implementation of counseling about composting in group of livestock of Mekar. The research was conducted in sub-district Dagangan of Madiun Regency. Selection of livestock group is done by purposive that is the only group of livestock that have made compost that is group of livestock of Mekar which is located in Kepet village. The research method used is case study with quantitative descriptive approach with scoring. The population is 44 people, the sample is based on the census. The results showed that: 1) the level of competence of farmers in composting is classified with the details of the competence of the preparation stage is low, the competence of the manufacturing process is low, and the competence of the storage stage is classified; and 2) drafting the extension plan based on the target and the purpose of extension so that the breeder know, understand and able to increase the C-Organic content and C / N Ratio on the compost according to the standard. Success shows the improvement of compost quality before and after counseling in accordance with the purpose of counseling.   Keywords: competence of breeder, livestock group of Mekar, draft extension, composting, extension

scholarly journals Evaluating COVID-19 Vaccination Website using DISCERN and QUality Evaluation Scoring (QUEST) Tools

2021 ◽  
Author(s):  
Akash Gajanan Prabhune ◽  
Aishwarya Mallavaram ◽  
Sachin Bhat ◽  
Samridhi Pandey ◽  
Ayesha Mehar Shagufta ◽  
...  
Keyword(s):  
Decision Making ◽  
United Arab Emirates ◽  
Ease Of Use ◽  
Average Score ◽  
Quality Of Information ◽  
Member States ◽  
Critical Information ◽  
Minor Elements ◽  
Selection Of

Abstract Background: The objective of this paper was to evaluate the COVID-19 vaccine registration website across UN-recognized member states for their portal quality, reliability, Ease Use and help to the general population in informed decision making.Methods: 12 UN member states (Countries) were selected based on the inclusion and exclusion criteria mentioned in the methodology section of this paper. PPS technique was used for sampling and selection of 12 countries from 193 UN member states. Post selection of UN member states the study used 2 step evaluation techniques, Step 1 The DISCERN checklist consists of 16 questions in three sections and is aimed to assess the reliability of information and quality of information; Step 2 The QUEST tool consists of 6 items with a subitem, Authorship, Attribution, Conflict of Interest, Complementarity, Currency, Tone. The authors developed a standard set of instructions for evaluating Vaccination Portals to bring uniformity in understanding and context setting.Results: DISCERN tool overall reliability score on the Likert scale of 0 to 5 was 4 (SD ± 1.28). On Quality of information regarding treatment choices, the average score was 3.4 (SD ± 1.67). The QUEST tool on ease of use, concision, and comprehensiveness demonstrated an average score of 18.1 (SD ± 8.3) out of 28.The vaccine registration portal of the Czech Republic was found to be most informative and was able to provide a piece of scientifically valid information on safety, efficacy, long-term short effects, choice of vaccine with attributable authors details. India, Bangladesh, Nigeria, South Africa scored relatively low to missing critical information on the website. The United Arab Emirates, Republic of South Korea, Indonesia, Australia, and Argentina had minor elements missing.Conclusions: COVID-19 vaccination portals vary in the quality of information and many were found unable to provide critical information for decision making on getting vaccinated

scholarly journals Assessment and Comparison of Various MCDM Approaches in the Selection of Manufacturing Process

2020 ◽  
Vol 2020 ◽  
pp. 1-16 ◽  
Author(s):  
Atef M. Ghaleb ◽  
Husam Kaid ◽  
Ali Alsamhan ◽  
Syed Hammad Mian ◽  
Lotfi Hidri
Keyword(s):  
Decision Making ◽  
Computational Complexity ◽  
Manufacturing Process ◽  
Group Decision ◽  
Die Casting ◽  
Multicriteria Decision Making ◽  
Sand Casting ◽  
Manufacturing Processes ◽  
Alternative Processes ◽  
Selection Of

The selection of manufacturing processes for a given application is a complex problem of multicriteria decision-making although there have been several different approaches that can be utilized to select a suitable alternative. However, identifying appropriate multicriteria decision-making approach from the list of available methods for a given application is a difficult task. This work suggests a methodology to assess different selection approaches, which are the technique for order of preference by similarity to ideal solution (TOPSIS), analytic hierarchy process (AHP), and VIKOR: stepwise procedure. This valuation was done depending on the following factors: number of alternative processes and criteria, agility through the process of decision-making, computational complexity, adequacy in supporting a group decision, and addition or removal of a criterion. A case study in this study was presented to analyse the evaluation methodology. The criteria used to evaluate and identify the best manufacturing process were categorized into productivity, accuracy, complexity, flexibility, material utilization, quality, and operation cost. Five manufacturing processes were considered, including gravity die casting, investment casting, pressure die casting, sand casting, and additive manufacturing. The results showed that each approach was suitable for the problems of manufacturing process selection, in particular toward the support of group decision-making and uncertainty modelling. Manufacturing processes were ranked based on their respective weights for AHP, TOPSIS, and VIKOR, and sand casting is the best. In terms of computational complexity, the VIKOR method performed better than TOPSIS and AHP. Moreover, the VIKOR and TOPSIS methods were better convenient to the selection of manufacturing processes for agility during the process of decision-making, the number of alternative processes and criteria, adequacy in supporting a group decision, and addition or removal of a criterion.

scholarly journals Microstructure and Mechanical Properties Evolution during Solution and Ageing Treatment for a Hot Deformed, above β-transus, Ti-6246 Alloy

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1114
Author(s):  
Mohammed Hayder Ismail Alluaibi ◽  
Elisabeta Mirela Cojocaru ◽  
Adrian Rusea ◽  
Nicolae Șerban ◽  
George Coman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Behaviour ◽  
Rolling Direction ◽  
Processing Route ◽  
Thermal Treatments ◽  
Deformation Degree ◽  
Fixed Temperature ◽  
Ageing Treatment ◽  
Thermal Solution ◽  
Strength And Ductility

The present study investigates the influence of hot-deformation, above β-transus and different thermal treatments on the microstructural and mechanical behaviour of a commercially available Ti-6246 titanium-based alloy, by SEM (scanning electron microscopy), tensile and microhardness testing techniques. The as-received Ti-6246 alloy was hot-deformed—HR by rolling, at 1000 °C, with a total thickness reduction (total deformation degree) of 65%, in 4 rolling passes. After HR, different thermal (solution—ST and ageing—A) treatments were applied in order to induce changes in the alloy’s microstructure and mechanical behaviour. The applied solution treatments (ST) were performed at temperatures below and above β-transus (α → β transition temperature; approx. 935 °C), to 800 °C, 900 °C and 1000 °C respectively, while ageing treatment at a fixed temperature of 600 °C. The STs duration was fixed at 27 min while A duration at 6 h. Microstructural characteristics of all thermomechanical (TM) processed samples and obtained mechanical properties were analysed and correlated with the TM processing conditions. The microstructure analysis shows that the applied TM processing route influences the morphology of the alloy’s constituent phases. The initial AR microstructure shows typical Widmanstätten/basket-weave-type grains which, after HR, are heavily deformed along the rolling direction. The STs induced the regeneration of α-Ti and β-Ti phases, as thin alternate lamellae/plate-like structures, showing preferred spatial orientation. Also, the STs induced the formation of α′-Ti/α″-Ti martensite phases within parent α-Ti/β-Ti phases. The ageing treatment (A) induces reversion of α′-Ti/α″-Ti martensite phases in parent α-Ti/β-Ti phases. Mechanical behaviour showed that both strength and ductility properties are influenced, also, by applied TM processing route, optimum properties being obtained for a ST temperature of 900 °C followed by ageing (ST2 + A state), when both strength and ductility properties are at their maximum (σUTS = 1279 ± 15 MPa, σ0.2 = 1161 ± 14 MPa, εf = 10.1 ± 1.3%).

scholarly journals Effect of Thermal Treatments on Sn-Alloyed Al-Mg-Si Alloys

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1801
Author(s):  
Florian Schmid ◽  
Peter J. Uggowitzer ◽  
Robin Schäublin ◽  
Marion Werinos ◽  
Thomas Ebner ◽  
...  
Keyword(s):  
Natural Aging ◽  
Positive Influence ◽  
Processing Route ◽  
Thermal Treatments ◽  
Intermetallic Particles ◽  
Aging Kinetics ◽  
High Level ◽  
Fast Quenching ◽  
Selection Of

Sn-alloying, by deploying comparatively high vacancy binding energy, mitigates the undesired natural aging behavior of 6xxx-alloys. Targeted selection of pre-aging parameters can have a positive influence on natural aging and paint-bake performance. In this study, we aimed to combine the two approaches of Sn-alloying and pre-aging. Our results indicate that alloys modified with 100 at.-ppm Sn require altered heat treatment. In terms of solution aging and quenching, we show that the cooling rate needed depends on the types of alloy. The rate must be adapted, according to the number of intermetallic particles, to guarantee a sufficiently high level of Sn atoms in solid solution. The rather high number of intermetallic phases in alloy EN-AW-6061 means that it requires fast quenching, while the comparatively low number of precipitate-forming elements in alloy EN-AW-6016 makes it less sensitive to quenching variations. We also show that Sn reduces pre-aging kinetics. The optimal pre-aging temperature and time were consequently found to increase when Sn is added. We also studied the effect of adding a further thermal spike to the usual long-term pre-aging, at different positions within the processing route. The results we present are discussed based on a simulation of vacancy evolution in the alloy when subjected to these treatments.

scholarly journals Selection of a green manufacturing process based on CAD features

2015 ◽  
Vol 87 (5-8) ◽  
pp. 1335-1343 ◽  
Author(s):  
Raoudha Gaha ◽  
Bernard Yannou ◽  
Abdelmajid Benamara
Keyword(s):  
Manufacturing Process ◽  
Green Manufacturing ◽  
Selection Of
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