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Cobalt–chromium (Co–Cr) alloys are the most widely used materials for removable and fixed dental prosthetic frameworks. The fitting accuracy between these components in dental prosthetic frameworks assembles (DPFAs) is largely influenced by the manufacturing method. This study presents a novel manufacturing method that combined two common techniques for obtaining one single framework: casting of Co–Cr inserts on top of parts previously manufactured by selective laser melting (SLM) of Co–Cr powder (CoM). Horizontal (n = 4) and vertical (n = 3) surfaces were microscopically analyzed (n = 770 count sum). The results revealed a high precision of the process and high fitting accuracy between the hybrid frameworks. The average distance measured between the frameworks in joined position was 41.08 ± 7.56 µm. In conclusion, the manufacturing of Co–Cr alloys DPFA using the CoM method reduced the deformation of hybrid frameworks and improved the joining accuracy between them.
Willi Uriciuc; Horatiu Vermesan; Ancuta Tiuc; Aranka Ilea; Adina Bosca; Catalin Popa. Casting Over Metal Method Used in Manufacturing Hybrid Cobalt-Chromium Dental Prosthetic Frameworks Assembles. Materials 2021, 14, 539 .
AMA StyleWilli Uriciuc, Horatiu Vermesan, Ancuta Tiuc, Aranka Ilea, Adina Bosca, Catalin Popa. Casting Over Metal Method Used in Manufacturing Hybrid Cobalt-Chromium Dental Prosthetic Frameworks Assembles. Materials. 2021; 14 (3):539.
Chicago/Turabian StyleWilli Uriciuc; Horatiu Vermesan; Ancuta Tiuc; Aranka Ilea; Adina Bosca; Catalin Popa. 2021. "Casting Over Metal Method Used in Manufacturing Hybrid Cobalt-Chromium Dental Prosthetic Frameworks Assembles." Materials 14, no. 3: 539.
The circular economy (CE) is a popular concept in the European Union (EU) space, which has been the subject of numerous research and substantiation activities. In the last years, there has been a growing interest in Romania regarding the characteristics of this new economic model and the principles on which it works. Referring to Romanian specialized literature currently available regarding the submitted topic, we consider that the theoretical part is insufficiently structured. In addition, by pointing out the applicability of the circular economy in Romanian space, we consider this to be represented mainly by the fragility of its effective and practical implementation. The examples of Romanian successes in the field of circular economy are limited, a fact that can be explained—from our perspective—through the aspect that in other EU countries, the process of development of CE has some precedents, a stronger background and a ”self-constructed” history in the topic. There is undoubtedly a necessity for adopting this new economic model, considering that, for the most part, Romanian economy is still dependent on the linear economic system. Starting from these arguments, the proposed article uses a thematic debate of the notion of circular economy, presenting, at the beginning, an incursion into the predominantly European variety of theoretical approaches. The selection of definitions and conceptualization is continued with an analysis of the stage of implementation of CE in Romania. The purpose of this approach is to investigate a niche identified in the Romanian space, not covered in the specialized scientific research and to expose the specificity of the process of transition of Romania to a circular economy, of the barriers encountered—namely, the problem related to the attitude and mentality regarding this new concept. We also point out that the intention of the study is to integrate a ”different” contemporary and very current economic concept into a real economy, and at the same time, to increase the visibility of its application at the level of a member country of the EU. The challenges encountered in the context of the increasingly present tendency in Romania of assimilating and complying with the precepts of the circular economy are also detailed, proposing, at the end of the study suggestions for improving the gaps identified at this level. The most realistic implementation of the circular model in Romania represents a qualitative plus for the human-society factor, as well as for the environment. In conclusion, we note that, despite the evolution of the number of theoretical approaches and concerns, the field of circular economy and the perspectives it proposes, continues to offer a favorable ground for further research.
Horațiu Vermeșan; Alexandrina Mangău; Ancuța-Elena Tiuc. Perspectives of Circular Economy in Romanian Space. Sustainability 2020, 12, 6819 .
AMA StyleHorațiu Vermeșan, Alexandrina Mangău, Ancuța-Elena Tiuc. Perspectives of Circular Economy in Romanian Space. Sustainability. 2020; 12 (17):6819.
Chicago/Turabian StyleHorațiu Vermeșan; Alexandrina Mangău; Ancuța-Elena Tiuc. 2020. "Perspectives of Circular Economy in Romanian Space." Sustainability 12, no. 17: 6819.
In recent years, natural materials are becoming a valid alternative to traditional sound absorbers due to reduced production costs and environmental protection. This study explores alternative usage of sheep wool as a construction material with improved sound absorbing properties beyond its traditional application as a sound absorber in textile industry or using of waste wool in the textile industry as a raw material. The aim of this study was to obtain materials with improved sound-absorbing properties using sheep wool as a raw material. Seven materials were obtained by hot pressing (60 ÷ 80 °C and 0.05 ÷ 6 MPa) of wool fibers and one by cold pressing. Results showed that by simply hot pressing the wool, a different product was obtained, which could be processed and easily manipulated. The obtained materials had very good sound absorption properties, with acoustic absorption coefficient values of over 0.7 for the frequency range of 800 ÷ 3150 Hz. The results prove that sheep wool has a comparable sound absorption performance to mineral wool or recycled polyurethane foam.
Simona Ioana Borlea (Mureşan); Ancuţa-Elena Tiuc; Ovidiu Nemeş; Horaţiu Vermeşan; Ovidiu Vasile. Innovative Use of Sheep Wool for Obtaining Materials with Improved Sound-Absorbing Properties. Materials 2020, 13, 694 .
AMA StyleSimona Ioana Borlea (Mureşan), Ancuţa-Elena Tiuc, Ovidiu Nemeş, Horaţiu Vermeşan, Ovidiu Vasile. Innovative Use of Sheep Wool for Obtaining Materials with Improved Sound-Absorbing Properties. Materials. 2020; 13 (3):694.
Chicago/Turabian StyleSimona Ioana Borlea (Mureşan); Ancuţa-Elena Tiuc; Ovidiu Nemeş; Horaţiu Vermeşan; Ovidiu Vasile. 2020. "Innovative Use of Sheep Wool for Obtaining Materials with Improved Sound-Absorbing Properties." Materials 13, no. 3: 694.
Thermoelectric generators can operate at small temperature differences providing enough electricity for low-power electronics, sensors in distribution networks, and biomedical devices. The article presents the obtaining of a thermoelectric generator and its electrical characteristics using usual substances. Experimental research was carried out using a mixture consisting of several substances (copper sulfate, calcium hydroxide, silicon dioxide, and sodium silicate) in different proportions. The mixture was inserted between two plates, one graphite (hot plate) and the other aluminum (cold plate), thus obtaining a thermoelectric generator. Electrical voltage, output current, and electrical power were measured at different temperatures.
Mihail Chira; Andreea Hegyi; Henriette Szilagyi; Horaţiu Vermeșan. Thermoelectric Generator Based on CuSO4 and Na2SiO3. Proceedings 2020, 63, 35 .
AMA StyleMihail Chira, Andreea Hegyi, Henriette Szilagyi, Horaţiu Vermeșan. Thermoelectric Generator Based on CuSO4 and Na2SiO3. Proceedings. 2020; 63 (1):35.
Chicago/Turabian StyleMihail Chira; Andreea Hegyi; Henriette Szilagyi; Horaţiu Vermeșan. 2020. "Thermoelectric Generator Based on CuSO4 and Na2SiO3." Proceedings 63, no. 1: 35.
Waste from information technology (IT) and telecommunication equipment (WITTE) constitutes a significant fraction of waste from electrical and electronic equipment (WEEE). The presence of rare metals and hazardous materials (e.g., heavy metals or flame retardants) makes the necessary recycling procedures difficult and expensive. Important efforts are being made for Waste Printed Circuit Board (WPCB) recycling because, even if they only amount to 5–10% of the WITTE weight, they constitute up to 80% of the recovered value. This paper summarizes the recycling techniques applicable to WPCBs. In the first part, dismantling and mechanical recycling techniques are presented. Within the frame of electro-mechanical separation technology, the chain process of shredding, washing, and sieving, followed by one or a combination of magnetic, eddy current, corona electrostatic, triboelectrostatic, or gravity separation techniques, is presented. The chemical and electrochemical processes are of utmost importance for the fine separation of metals coming from complex equipment such as WPCBs. Thermal recycling techniques such as pyrolysis and thermal treatment are presented as complementary solutions for achieving both an extra separation stage and thermal energy. As the recycling processes of WPCBs require adequate, efficient, and ecological recycling techniques, the aim of this survey is to identify and highlight the most important ones. Due to the high economic value of the resulting raw materials relative to the WPCBs’ weight and composition, their recycling represents both a necessary environmental protection action, as well as an economic opportunity.
Horațiu Vermeșan; Ancuța-Elena Tiuc; Marius Purcar. Advanced Recovery Techniques for Waste Materials from IT and Telecommunication Equipment Printed Circuit Boards. Sustainability 2019, 12, 74 .
AMA StyleHorațiu Vermeșan, Ancuța-Elena Tiuc, Marius Purcar. Advanced Recovery Techniques for Waste Materials from IT and Telecommunication Equipment Printed Circuit Boards. Sustainability. 2019; 12 (1):74.
Chicago/Turabian StyleHorațiu Vermeșan; Ancuța-Elena Tiuc; Marius Purcar. 2019. "Advanced Recovery Techniques for Waste Materials from IT and Telecommunication Equipment Printed Circuit Boards." Sustainability 12, no. 1: 74.
New composite materials based on sawdust as reinforcing material and polyurethane foam as a binder agent, exhibiting sound absorbing proprieties, have been obtained. Due to the sound-absorbent proprieties exhibited by these type of materials, 11 new composite systems have been obtained varying the type and the size of sawdust particles, the percentage of binder and the thickness of material. The sound absorption properties of the new obtained materials are directly correlated with the composition, the thickness of materials as well as the air gap samples and the rigid wall. In addition, the morphological and thermal conductivity proprieties and the mechanical ones, of the new obtained materials, were carried out.
Ancuţa Elena Tiuc; Ovidiu Nemeş; Horaţiu Vermeşan; Adina Cristina Toma. New sound absorbent composite materials based on sawdust and polyurethane foam. Composites Part B: Engineering 2018, 165, 120 -130.
AMA StyleAncuţa Elena Tiuc, Ovidiu Nemeş, Horaţiu Vermeşan, Adina Cristina Toma. New sound absorbent composite materials based on sawdust and polyurethane foam. Composites Part B: Engineering. 2018; 165 ():120-130.
Chicago/Turabian StyleAncuţa Elena Tiuc; Ovidiu Nemeş; Horaţiu Vermeşan; Adina Cristina Toma. 2018. "New sound absorbent composite materials based on sawdust and polyurethane foam." Composites Part B: Engineering 165, no. : 120-130.
The main purpose of this work is to investigate the influence of ion nitriding on thermal shock behaviour of two stainless steel grades (austenitic and martensitic). Samples made from the two steel grades were first ion nitrided in dissociated ammonia and H-N-CH mixture and then subjected to thermal shock from 600C and 500C by using a home made apparatus. The study put into evidence two different types of crack initiation and crack growth on the two steel grades. Possible mechanisms responsible for such cracking behaviour are also proposed.
Vasile Rus; Gavril Negrea; Horatiu Vermesan. Experimental research concerning the thermal shock behaviour of some ion nitriding stainless steels. International Journal of Microstructure and Materials Properties 2007, 2, 64 .
AMA StyleVasile Rus, Gavril Negrea, Horatiu Vermesan. Experimental research concerning the thermal shock behaviour of some ion nitriding stainless steels. International Journal of Microstructure and Materials Properties. 2007; 2 (1):64.
Chicago/Turabian StyleVasile Rus; Gavril Negrea; Horatiu Vermesan. 2007. "Experimental research concerning the thermal shock behaviour of some ion nitriding stainless steels." International Journal of Microstructure and Materials Properties 2, no. 1: 64.
A fundamental study is undertaken of the mechanism of the formation and dissolution of lead sulfate on the negative electrode in a lead–acid battery. This involves in situ examination of a lead sheet, on which a small amount of BaSO4 or SrSO4 powder is fixed by pressing, in sulfuric acid solution by means of electrochemical atomic force microscopy (EC-AFM) combined with cyclic voltammetry (CV). It is found that both BaSO4 and SrSO4 provide seed crystals for the precipitation of PbSO4. The PbSO4 crystals are formed more rapidly on SrSO4 than on BaSO4 during the oxidation (discharge) process. The dissolution of PbSO4 crystals formed on SrSO4 crystals is very slow during the reduction (charge) process.
H Vermesan; N Hirai; M Shiota; T Tanaka. Effect of barium sulfate and strontium sulfate on charging and discharging of the negative electrode in a lead–acid battery. Journal of Power Sources 2004, 133, 52 -58.
AMA StyleH Vermesan, N Hirai, M Shiota, T Tanaka. Effect of barium sulfate and strontium sulfate on charging and discharging of the negative electrode in a lead–acid battery. Journal of Power Sources. 2004; 133 (1):52-58.
Chicago/Turabian StyleH Vermesan; N Hirai; M Shiota; T Tanaka. 2004. "Effect of barium sulfate and strontium sulfate on charging and discharging of the negative electrode in a lead–acid battery." Journal of Power Sources 133, no. 1: 52-58.
Nobumitsu Hirai; Horatiu Vermesan; Masashi Shiota; Toshihiro Tanaka. Effect of Barium Sulfate on Negative Electrode of Lead Acid Battery-An Approach with In-Situ EC-AFM Observation-. Journal of the Japan Institute of Metals and Materials 2004, 68, 35 -38.
AMA StyleNobumitsu Hirai, Horatiu Vermesan, Masashi Shiota, Toshihiro Tanaka. Effect of Barium Sulfate on Negative Electrode of Lead Acid Battery-An Approach with In-Situ EC-AFM Observation-. Journal of the Japan Institute of Metals and Materials. 2004; 68 (2):35-38.
Chicago/Turabian StyleNobumitsu Hirai; Horatiu Vermesan; Masashi Shiota; Toshihiro Tanaka. 2004. "Effect of Barium Sulfate on Negative Electrode of Lead Acid Battery-An Approach with In-Situ EC-AFM Observation-." Journal of the Japan Institute of Metals and Materials 68, no. 2: 35-38.