Teuta Dilo - Academia.edu (original) (raw)

Papers by Teuta Dilo

Many questions about cultural and economic exchanges or conflicts and wars can find answers in th... more Many questions about cultural and economic exchanges or conflicts and wars can find answers in the metal production technology. This is the reason why it is very important to study the processing technology in antique times. On the other hand corrosion products and microelements present in the microstructure can give valuable information about the object preservation and the mineral used as raw material. Since money did not appear until the III century B.C. in today Albania, many types of objects such as axes and swords were used to purchase goods. But in order to determine an object usage purpose the archaeological and historical point of view should be taken into account, besides the analytical results. A 0.675m long sword which dates to the XIV-XIII century B.C. was found in the surroundings of Shkodra, northern Albania. This antique object was analyzed with X ray fluorescence (XRF), optical microscopy with Vickers microhardness tester (OM) and scanning electron microscopy – energy dispersive X rays spectroscopy (SEM-EDS). Thereby respectively information about the alloy composition, microstructure, corrosion products, microhardness, production technology, usage purpose, inclusions and mineral used for the object production was obtained. The sword results a casted copper-tin alloy with oxidized phases of the first and second corrosion layer. Despite the not very high microhardness value and the production method, the alloyed sword was intended for war combat purposes. Last but not least the sulphur inclusions indicate the possible usage of sulphide mineral in which northern Albania is very rich.

2017 UBT International Conference, 2017

Ternary binders are defined in this study as compositions of Calcium Aluminate Cement (CAC), Ordi... more Ternary binders are defined in this study as compositions of Calcium Aluminate Cement (CAC), Ordinary Portland Cement (OPC) and Calcium Sulfate (̅). Several mixtures were studied, calorimetric and shrinkage technique has been used to follow the hydration during 24 hours. The XRD technique is used as support for the analysis of the hydration products. The results have shown that the initial amount of and ̅ play a key role in the hydration of / / ̅ mixtures especially affecting the formation of ettringite. The mechanism of reactions (hydration kinetic) and the reactions speed (acceleration or retardation) depends by the aggregates (LSP, QP) put in the different binders. The addition of re-dispersible powders induced retardation in hydration kinetics, longer setting times and also changed the dimensional stability. Comparison of the phase development monitored by in-situ XRD was performed.

Proceedings of The 4th Global Virtual Conference, 2016

Physica B: Condensed Matter, 2010

The microstructure of three silver coins of the 3rd century B.C. from the Illyrian King Monounios... more The microstructure of three silver coins of the 3rd century B.C. from the Illyrian King Monounios and the ancient Greek cities of Dyrrachion and Corcyra, belonging to the Kreshpan hoard, was determined with X-ray diffraction and transmission electron microscopy in order to investigate their minting method. It is deduced that the coins are characterized by a large number of structural defects, mainly dislocations, twins and microtwins, which in some cases were bent. These crystal defects are common in each of the coins examined. This information allowed the formulation of a possible minting method. Since twins in FCC metals are formed with thermal treatment, and mechanical twinning is rather improbable, it seems that the coins were initially hot-worked. Bent twins indicate that working continued during cooling. Especially for the Corcyra coin it was deduced that it was treated at higher temperature or its cooling rate was lower.

Albania is situated west of the Balkan Peninsula while Shkodra and Durrës are respectively north-... more Albania is situated west of the Balkan Peninsula while Shkodra and Durrës are respectively north-western and western cities. The objects of this study are a fibula (IX-VIII BC) found in Shkodra and a snake bracelet (III-I BC) found in Durrës. The purposes of this research paper are to study the chemical composition, pro-duction technology, corrosion products, microstructure and the possible minerals used for the objects' man-ufacture. To fulfil these tasks the objects' samples have been analysed with μ-XRF, OM, Vickers microhard-ness tester and SEM-EDS. Both objects resulted authentic copper-tin alloys with less than 2% of lead. They have approximate microhardness values (116.2HV and 113.6HV), with corrosion products from the first and second oxidized layer. The fibula and the snake bracelet has been casted, hot and cold worked to obtain the final shape. Both objects have lead and copper-iron-sulphur inclusions which suggest the possible use of copper-iron sulphite minerals.

$Research paper thumbnail of Thickness determination of TiN and TiAl coatings on steel substrates using X-ray diffraction method and their composition measurements by GD-OES$

Surface and Interface Analysis

Journal of Archaeological Science: Reports, 2016

Albania lies in the southeast part of Europe, in the Balkan Peninsula and one of its northern old... more Albania lies in the southeast part of Europe, in the Balkan Peninsula and one of its northern oldest city is Shkodra. This study includes eight Albanian-Dalmatian axes (XIII-XII B.C.) and six celts (XI-X B.C.), found in Shkodra's suburbs. Their elemental composition is analyzed with X ray fluorescence spectroscopy (XRF), the axes' microstructure together with the corrosion products are observed using reflected and polarized optical microscopy (OM). Finally the microstructure as well as the composition of various phases are studied with scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS). All axes result copper-tin alloys associatedwith elements such as Pb, Fe, Ni and As. The Albanian-Dalmatian axes may have been used asmonetary toolswhile the celts may have served as working tools. Several phases in the microstructure suggest the possibility of sulphide copper ore usage.

AIP Conference Proceedings, 2007

The microstructure of three silver coins of the IIId century B.C. from the Illyrian king Monounio... more The microstructure of three silver coins of the IIId century B.C. from the Illyrian king Monounios, the ancient Greek city of Dyrrachion and of Korkyra was studied with XRF and microscopy. From this investigation it turned out that these coins have different chemical composition and microstructure that imply different minting method.

Në këtë s tudim ja në s tudiua r tre objekte hekuri të emërtua ra hanxha r, me qellim s tudi min ... more Në këtë s tudim ja në s tudiua r tre objekte hekuri të emërtua ra hanxha r, me qellim s tudi min e teknologjisë të prodhi mi t në këto periudha. Objektet i përkasin peri udha ve, kul tura ve si dhe vendbanimeve të ndryshme në rrethina t e Shkodrës. Metoda t anali tike që janë përdorur në këtë s tudim janë : XRF-për përbërjen elementa re të të tre objekteve si edhe mikros kopia optike e cila është përdorur vetëm për objektin hanxha r 3 i cili njihet si hanxhar lëkurë punues. Nga rezul tatet me μ-XRF mund të dalim në përfundi min që të gji thë objektet përmbajnë hekur mbi 98%. Elementë ki mik të tjerë të pra nishëm janë: Mn deri në 0.38% (hanxha r 3) dhe Co deri në 0.99% (hanxhar 1). Co mendohet të jetë si një papas tërti. Tek hanxha r 1 përvec Fe, Co dhe Mn, përmban në masë shumë të vogël Cu 0.1-0.01%. Tek ha nxhar 3 mund të shihet qartë struktura heterogjene e widmanstatte.

$Research paper thumbnail of The Study of Phase Compound and the Degree of Crystallinity of Recycled LDPE by X-ray Diffractometer and Optical Microscope$

International Journal of Science and Research (IJSR)

To describe the creep behaviour of metallic materials mainly a power law firstly given by Norton ... more To describe the creep behaviour of metallic materials mainly a power law firstly given by Norton like dε/dt = A σ n exp(-Q/R T) is used. According to the liquidus temperature of these phases we can conclude, that creep takes place mainly in the Sn-solid solution. The values of n we have found from our creep experiments amounts between 1.8 and 2.9. Based on the experimental values of n we can conclude that the main mechanisms of creep are dislocation mechanisms. The activation energies experimentally founded are in the range between Q/R=2363 and Q/R=5761. The A-parameter increases with the increase of the contact area, with the decrease of Q-activation energy and with the decrease of n-exponent creep stress.

The aim of this research, is the experimental study of the nitriding layer during the process of ... more The aim of this research, is the experimental study of the nitriding layer during the process of nitriding in gases in Steel 17CrMoV10. It is well known that the process of nitriding is a thermal-chemical process that occurs at temperatures 500-600°C, where the enrichment of the peripheral surface with nitrogen is achieved. This surface is also, called a nitriding layer or diffusions layer. The aim of the process of gas-nitriding is the improvement of the properties of the material, such as, increase of the mechanical hardness and corrosion resistance, increase of resistance under thermal activities and resistance against consumption, etc. Final results of the process depend on the parameters that define the process: Temperature, duration of the process, concentration of the alloy elements in steel, etc. Depending on these parameters, by experimental methods-metallographic, microhardness measurements and microsond-we have studied the diffusions layer.

A new and more effective method for protecting steel from corrosion is coating it with galfan. Ga... more A new and more effective method for protecting steel from corrosion is coating it with galfan. Galfan is a metallic melting composed of 95% Zn and 5% Al. In this alloy, purely steel samples are dipped; during this process reactions between iron, zinc and aluminum are caused. As an outcome, we gain a new material, steel coated with a galfanic layer. The microstructure of galfanized steel and some mechanical properties are presented here.

Ancient copper and bronze artefacts from different Albanian territories have been analyzed by X-r... more Ancient copper and bronze artefacts from different Albanian territories have been analyzed by X-ray fluorescence to determine the type of alloy and elemental composition. Three bronze coins from Dyrrahu, dating the III-rd – II-nd century B.C., are composed of copper-tin-lead. A nail excavated at Dyrrahu, dating the IV-rth – III-rd century B.C., is composed from copper. Also, another nail dating the VI-th – IV-rth century B.C. excavated inside an amphora in an ancient ship in Saranda, is composed of copper. The microstructure of those ancient objects is analyzed using light metallographic microscope to identify how they were made. Introduction: The main goals of this study are the determination of the artefacrs' chemical composition, microstructure and morphology and also the identification of their production procedure (how they were made).

The ancient objects analyzed in this study are a sword from Erseka, dating the XII–X century B.C.... more The ancient objects analyzed in this study are a sword from Erseka, dating the XII–X century B.C., and a shield discovered in Apollonia, dating the IV century B.C. These ancient bronze (copper – tin) artefacts from two different Albanian territories have been analyzed by X-ray-fluorescence analysis to determine the type of alloy and elemental composition. Afterwards their microstructure was investigated using the optical metallographic microscope and the microhardness test, to identify how they were manufactured. The optical microscope with polarized light was used to analyze the corrosion products and to verify the authenticity of the ancient sword and shield.

$Research paper thumbnail of Thermal analysis with the heating rate 2K/min and characterization of the spinel structure LiMn2O4 with X ray diffraction and scanning electronic microscope$

LiMn2O4 studied in this work has cubic spinel structure. This material is being used more and mor... more LiMn2O4 studied in this work has cubic spinel structure. This material is being used more and more in the cathode production of the rechargeable lithium ion batteries for different equipments such as cell phones, laptops, digital cameras, electric cars, etc. LiMn2O4 samples were prepared according to the sol-gel method. To study the possible reactions in the spinel structure LiMn2O4 three samples were subjected to thermo-differential and thermo-gravimetric analysis with the heating rate 2K/min (or 2°C/min). From the thermo-differential analysis (TD) the two stages of the reaction were defined and from the thermo-gravimetric (TG) analysis the mass losses of the samples were defined during a controlled thermal programme. Meanwhile from the first derivative of the TG curve the temperature at which the reaction starts was defined and the X rays diffraction defined the present phases, lattice parameters and mean grain sizes after the chemical reaction.