Metallurgical and Materials Engineering

This paper pioneers the integration of hyperspectral imaging and robotics for the automated analysis of cultural heritage, representing a measurable advancement over existing manually operated systems. For the first time in the cultural heritage domain, a compact push-broom hyperspectral camera working in the VNIR range has been successfully mounted on a robotic arm, enabling precise and repeatable acquisition trajectories without the need for manual intervention. Unlike traditional approaches that rely on fixed paths or manual repositioning, the proposed approach allows dynamic and programmable imaging of both planar and volumetric objects, greatly improving adaptability to complex geometries. The integrated system achieves spectral reliability comparable to established manual methods, while offering superior flexibility and scalability. Current limitations, particularly regarding the illumination setup, are discussed alongside planned optimisation strategies.

Tuproq pH qiymati o'simliklarning o'sishiga ta'siri o'simlik ildizlari uchun mavjud bo'lgan muhim oziq moddalarning turi va miqdoriga katta ta'sir qiladi. Har bir o'simlik o'zining tavsiya etilgan pH qiymati oralig'iga ega. Sababi shundaki, pH tuproqdagi ozuqa moddalarining shakllanishiga ta'sir qiladi va o'simliklar turli xil ozuqa moddalariga bo'lgan ozuqa ehtiyojini hosil qiladi. Tuproqning pH darajasi 0 dan 14 gacha diapazonda o'lchanadi.

In this study, hybrid composites of Al7075 reinforced with boron carbide (B4C), titanium (Ti), and
graphite (Gr) were synthesized using the stir casting technique and was investigated to assess their
suitability for aerospace applications. Six different compositions were prepared by varying the vol% of
B4C and Ti and maintaining a constant vol% of graphite in all composites. The physical andstructural
characteristics were analyzed through density measurements, porosity evaluation, and x-ray
diffraction (XRD) analysis. The experimental and theoretical density values showed a decreasing trend
with increased reinforcement, Porosity values were found to decrease with higher Ti content. XRD
confirmed the presence of Al matrix phases along with B4C, Ti, and graphite, , indicating uniform
distribution and phase stability. Corrosion resistance was assessed using static immersion tests,
polarization studies, Nyquist plots, and Bode plots. The base alloy demonstrated susceptibility to
galvanic corrosion, with minimal passivation. Composites with boron carbide showed moderate
corrosion rate (−1.479 mm y−1), and those with titanium exhibited remarkable improvements
(−1.116 mm y−1). The polarization curves of the reinforced composites displayed lower current
densities in the anodic region with an Ecorr and Icorr value of 776.856 mV and 8.332 mA for composite
reinforced with boron carbide and 727.265 mV and 8.001 mA for composites reinforced with
titanium, indicating enhanced passivation and reduced corrosion rates. Nyquist plots revealed larger
semicircular arcs for titanium-reinforced composites, signifying higher charge transfer resistance
(Rct). Among the tested compositions, the hybrid composite with 7 vol% Ti, 3 vol% B4C, and 2 vol%
Gr exhibited improved passivation, and superior corrosion resistance.

Increasing the selectivity of the flotation separation of copper and molybdenum sulfides
during the beneficiation of complex copper-porphyry ores is a relevant technological challenge,
the solution to which is largely determined by the characteristics of the froth layer. This paper
presents a comprehensive comparative assessment of the effectiveness of the standard frother T92 and the new-generation reagent Penoflot-1304. The research included laboratory determination
of physicochemical properties (surface tension), the study of chalcopyrite flotation kinetics with
the calculation of rate constants, as well as the analysis of industrial trial results. It was established
that Penoflot-1304 possesses significantly higher surface activity, providing a lower surface
tension (21.75 mN/m) compared to T-92 (26.02 mN/m). This property ensures the creation of a
more stable froth, which is confirmed by the results of kinetic tests: new composite formulations
showed a flotation rate constant of up to k=0.2373 min⁻¹ and a maximum chalcopyrite recovery of
up to 88.97 %. The key result of the industrial trials on ore from the Kalmakyr deposit was a
significant increase in the overall recovery of molybdenum—from 51.56% (using T-92) to 70.89%
(with Penoflot-1304)—while maintaining comparable copper recovery rates. Thus, the
technological and economic feasibility of the industrial implementation of the Penoflot-1304
reagent has been proven, with an estimated annual economic effect of 1.7 million US dollars from
processing 30 million tons of ore.

Results of the recent developments of J.C.Steele&Sons Inc. do show that the stiffextrusion technology can be very efficient for the agglomeration of disperse anthropogenic and natural metal containing and carbonaceous substances. The Brex (Extrusion Briquettes) have a mechanical strength sufficiently high for the transportation and for the stockpiling for further strengthening storage at the moment of extrusion through the die. We have investigated the cold (mechanical) strength, the behavior during heating under the reducing atmosphere as well as the hot strength (in accordance with ISO Standard) of the Brex made of the metallurgical sludge, iron-ore concentrates, manganese ore fines, coke breeze and coal. The results show that the metallurgical properties of the Brex allow for their successful utilization in various processes of the extractive metallurgy.

The efficiency of preliminary homogenization of a briquetted charge using bentonite is shown. The dynamics of increasing the strength of commercial extrusion briquettes (brex) during storage under natural conditions is studied. A combined cement-bentonite binder is used to reveal a new effect of local maximum of the cold strength of brex at the third day of hardening, which is accompanied by a change in the character of its fracture.

The results of the laboratory study and the full-scale industrial testing of the extruded briquettes (BREX) application for the production of the Ferroalloys are discussed. Stiff vacuum extrusion agglomeration provides for the high metallurgical properties of the agglomerates leading to the economic attractiveness of this technology. BREX can be efficiently used as one of the essential charge component (up to 30% of the ore part of the charge) for the Silicomanganese smelting thus improving technical and economical parameters of the furnace and decreasing the self-cost of the Silicomanganese production.

Industrial stiff vacuum extrusion briquettes (BREX) producing line can efficiently provide for the smallscale blast furnace (BF) operation with 100% briquetted charge. Physical and metallurgical properties of the BREX are being investigated. A new effect of the non-linear strengthening of the BREX bonded with the combined Portland cement and Bentonite binder is described. Application of this combined binder results in the local maximum of the cold compressive strength of the BREX on third day of strengthening. Hot strength mechanism of the BREX is explained and was found to be related with creation of the metallized shell on their surface, sintering of the iron-containing particles and further creation of the metallicc phase surrounded by the silicates and ferrites. The addition of the iron ore fines to the BREX composition can improve their sintering during reduction thus helping to keep the integrity of the agglomerates. Results of the industrial operation of the small-scale BF with BREX are analyzed. The consumption of coke in the BF at 100% of BREX does not exceed 500 kg/t compared with 680 kg/t for the smelting without BREX.

Vücudumuzun yükünü taşıyan diz eklemleri zamanla aşınmaya ve görevini yerine getiremez duruma gelmekte, ağrı ve acıya neden olmaktadır. Günlük aktiviteleri kısıtlanan hastalar için çözüm Total Diz Artroplastisinde (TDA) bulunmuştur. Bu, Femur ve Tibia kemik kıkırdak dokularının yerine geçen metal bileşenler ve menisküs yerine geçen polietilen insert kullanılarak implantın yerleştirildiği bir ameliyattır. Burada kullanılan metaller sert ve polietilen de metallere nispeten daha yumuşak olduğundan bir aşınma problemi oluşturmaktadır. Bu aşınmanın belirlenmesi ve implantın ömrünün hesaplanması da çözülmesi gereken problemlerden biridir. Bu çalışmada dinamik yükleme altındaki polietilen insertin yürüyüş döngüsündeki fleksiyon açısının değişimi dikkate alınarak aşınması çalışılmıştır. Bu amaçla Fleksiyon, Anterior-Posterior (AP) öteleme ve Internal-Eksternal (IE) rotasyon hareketleri ile birlikte Sonlu Elemanlar modeli oluşturulmuştur. Aşınma modeli olarak temas basıncından bağımsız Archard aşınma modeli kullanılmıştır. Literatürden elde edilen gerçekçi yüklemeler altında insert yüzeyindeki basınç ve aşınma miktarları elde edilmiştir. Her üç durum için devir sayısı arttıkça basıncın azaldığı aşınma miktarının ise arttığı görülmüştür. AP ötelemesi ve özellikle IE rotasyonun artan çevrimle birlikte Polietilen insert üzerindeki aşınmayı azalttığı belirlenmiştir.

Повышение плотности технической воды и снижение заряженности от илистых дисперсий и мутности с помощью селитры и солипо методу Бабиева Сергея Ивановичаосуществлённый методом соединения многовалентных ионов. Позволивший удалить взвешенные твёрдые частицы, которые вызывают мутность воды, путём объединения их в более крупные агрегаты (хлопья).

There is high level of antimicrobial resistance globally. Most commercial drugs are now becoming ineffective every day. Hence there is a need to develop new antimicrobial drugs. The aim of the research was to synthesize 1-methyl-4nitro-imidazole-5-N, N-diethylsulphonamide and determine its antimicrobial activities against bacteria and fungi. N,N′-Dimethyloxamide was synthesized from reaction between diet hyloxalate and methylamine. The compound became cyclizedon reacting with phosphorus(V) chloride to form 1-Methyl-5-chloroimidazole. 1-Methyl-5chloroimidazole was subjected to nitration using nitric acid and sulphuric acid to give 1-Methyl, 4nitro-5-chloroimidazole. The treatment of 1-Methyl, 4-nitro-5-chloroimidazole with hydrogen sulphide resulted in the formation of 1-Methyl, 4nitro-5-thiolimidazole which was converted to 1-Methyl-4-nitro-imidazole-5-sulphonyl chloride. The compound was reacted with diethyl amine leading to the synthesis of 1-methyl-4 nitroimidazole-5-N,Ndiethylsulphonamide. Antimicrobial activities of 1-methyl-4-nitroimidazole-5-N, N-diethylsulphonamide was investigated using four bacteria and two pathogenic fungi. The results showed that the synthesized compound was active against tested organism, even though the standard used was more active.

The majority of thermoplastics are not feasible substituted and non-biodegradable. To overcome these issues, recycling is a part of an effort to reduce plastic waste and stop serious pollution problems. Therefore, a sustainable plastic waste management strategy must be established to manage a large amount of generated waste. Polyethene is one of the most widely used commodity thermoplastics because of its outstanding properties, in particular easy processability, recycling ability, the versatility of applications. Generally used mineral fillers for the Polyethylene compounding are talc, calcium carbonate, glass beads, mica, silica, fibres and calcium silicate compound [1]. In this wollastonite was taken in powder form and mixed with recycled polyethene at various proportions, extruded through a twin-screw extruder by the melt mix process. This extrudate can be pelletized and used for making standard specimens as per the international standard Tests. Flexural properties were studied on wollastonite based recycled polyethene composites. There is an improvement in the flexural property after adding wollastonite. The test result was compared with the base material and there is an improvement in the recycled material after reinforcing with wollastonite filler.

Recycling polyethene plays an important role because the consumption of polyethene is more compared to all other plastic materials. Diverting discarded plastics from the refuse stream and turning them into new goods keeps these persistent materials out of landfills and the natural environment to improve the properties of recycled polyethene material, it was reinforced with a good filler[1]. To overcome this and make effective use of recycled polyethene it was reinforced with wollastonite[2]. In this wollastonite was taken in powder form and mixed with recycled polyethene at various proportions, extruded through a twin-screw extruder by the melt mix process. This extrudate can be pelletized and used for making standard specimens as per the international standard Tests. The test result was compared with the base material and there is an improvement in the recycled material after reinforcing with wollastonite filler.

The occurrence of abnormal grain growth (AGG) in AA5182 alloy during annealing imposes severe restrictions on processing parameters and deteriorates mechanical properties. In this work, we investigated the effect of chemical composition on the appearance of abnormal grain growth by varying Mg and Mn content in the range of composition limits for standard AA5182 alloy, 4.0-5.0% Mg, and 0.2-0.5% Mn, respectively. Thermo-mechanical processing of alloys included cold rolling with reductions ranging from 40 to 85%, followed by annealing in the temperature range from 350 to 520 °C. The results showed that the rise in alloying elements content drives the onset of abnormal grain growth toward higher temperatures. The increase in the cold rolling reduction degree promotes abnormal grain growth and lowers its onset temperature. Abnormal grain growth and grain boundary mobility showed strong anisotropy related to rod-like shape and alignment of Al6Mn(Fe) dispersoids through Zener pinning.

One artefact of the archaeological cultural heritage from Roman period (IV century) that was found near Šabac in Serbia, was analysed. In corrosion products of the artefact (knife), dominant phases were goethite (α-FeOOH) and magnetite (Fe 3 O 4 ). Presence of these types of corrosion products explains a good preservation of the base metal (iron) over the centuries and stability after excavation. Also, the less stable lepidocrocite (γ-FeOOH) and the phases that come from rocks and land surrounding environment (like SiO 2 ) were identified in the corrosion products. Phases containing chloride ions (i.e. akaganéite) have not been detected in the corrosion products. This indirectly indicates that the amount chloride ions were rather low in underground exploitation conditions.

In this study, fully annealed AA5083 type alloy sheets with 1 mm in thickness were processed by accumulative roll bonding (ARB) at room temperature, up to 6 ARB cycles. It was found that microstructure was refined and mechanical properties were significantly improved with ARB processing. The maximum achieved values of hardness and tensile strength were two and three times greater than that of the initial material, respectively. This was attributed to the intensive strain hardening and grain size refinement which occurred during ARB deformation. However, the uniform elongation values were decreased by increasing the number of ARB cycles, and early fracture was registered. SEM fractography of fractured surfaces after tensile tests revealed a typical ductile fracture of ARB processed specimens, which was changed with ARB deformation. It was observed that ductile area on the fractured surfaces and the amount of necking, which occured before fracture, were decreased with increasing the n...

The Helix-Light-Vortex (HLV) theory proposes that elementary particle properties emerge from resonant phenomena in a helically modulated field within a discrete, quasicrystalline lattice. This paper presents a two-phase experimental proposal to test the core postulates of HLV-Single-Cell Resonance (SCR) for leptons and Tri-Cellular Coupling (TCC) for hadrons-using analog quantum simulations in optical lattices or time-crystal architectures. The experiments are designed to provide falsifiable evidence for geometric-emergent particle models, with quantitative predictions grounded in established quantum simulation techniques. Successful outcomes would support a paradigm shift from point-like particles to resonant states of a discrete spacetime.

Many of the engineers and researchers have done their research on composite materials and they found that the composite which are made from two different materials with different chemical and physical property that, when combined ,produce a material with characteristics different from individual components .Both artificial and natural fibers will be used for the preparation of samples. The samples will be made from epoxy, bamboo, flax, glass fibers by using hand layup method. Then tribological test of the material will be done by using those samples by using pin on disc apparatus. From the outcome the following result will be calculated i.e wear rate, coefficient of friction, volume loss, frictional force, surface roughness.

Ushbu jurnal 2019-yildan boshlab O'zbekiston Respublikasi Oliy attestatsiya komissiyasi Rayosati qarori bilan fizikamatematika, kimyo, biologiya, falsafa, filologiya va pedagogika fanlari bo'yicha Oliy attestatsiya komissiyasining dissertatsiyalar asosiy ilmiy natijalarini chop etish tavsiya etilgan ilmiy nashrlar ro'yxatiga kiritilgan. "NamDU ilmiy axborotnomasi -Научный вестник НамГУ" jurnali O'zbekiston Matbuot va axborot agentligining 17.05.2016-yildagi 08-0075 -raqamli guvohnomasi hamda O'zbekiston Respublikasi Prezidenti Administratsiyasi huzuridagi Axborot va ommaviy kommunikatsiyalar agentligi (AOKA) tomonidan 2020-yil 29-avgust kuni 1106-sonli guvohnomaga binoan chop etiladi. "NamDU Ilmiy Axborotnomasi" elektron nashr sifatida xalqaro standart turkum raqami (ISSN-2181-1458) ga ega. NamDU Muvofiqlashtiruvchi Kengashining 2024-yil 26-noyabrdagi 8-sonli yig'ilishida muhokama qilinib, ilmiy to'plam sifatida chop etishga ruxsat etilgan (Bayonnoma № 8). Maqolalarning ilmiy saviyasi va keltirilgan ma'lumotlar uchun mualliflar javobgar hisoblanadi.

Steel is one of the most important materials used in modern society. The majority of the steel produced today is based on the use of coke and contributes a lot to greenhouse gases emission. Many researchers have been laid on the possibility to replace part of the fossilbased energy source in iron making with renewable, biomass-derived reducing agent. The main problems of this replacement are some difference of in quality between coke and wood charcoal (more reactive, less strength and carbon content) It causes a little shutdown of production in blast furnace and additional cost to modify a furnace. The aim of this paper was to determine in a statistical manner how carbonizations parameters impact the charcoal quality, especially reactivity and mechanical parameter. We applied a random factorial design and used the General linear System procedure to perform the statistical analysis. The experimental study was carried out using Eucalyptus Urophylla and Eucalyptus Camadulensis wood and involved two carbonization temperature (350 and 600°C), two relative working pressure (2 and 6 bars) and two heating rates (1 and 5°C/min). Six response variables were analyzed and discussed following a random factorial design: the charcoal yield (y char ), the fixed carbon content (C f ), the bulk density (D), the compressive strength (R m ), friability (F) and the reactivity (R) of charcoal. Except for the friability of charcoal, all other property are well correlate with carbonization parameter. In the range of low carbonisation parameter, reactivity of charcoal is affected only by carbonization temperature.

número de colegiado XXXXXX, con D.N.I. 77.630.773 T, y domicilio en Martorell con codigo postal 08760 ubicado en C/ Gelida nº 6 1er 1a, ha sido el autor del proyecto de la implantación de una empresa de corte por agua a presión y láser Profesor tutor: J.J de Felipe Manresa, 11 de Enero del 2007 UPC -EPSEM brought to you by CORE View metadata, citation and similar papers at core.ac.uk provided by UPCommons. Portal del coneixement obert de la UPC 4-DIRECCIONES DE EMPRESAS ( COMPETENCIA ):

Debido a que las oportunidades de negocio pueden surgir por múltiples medios, y a que la efectividad en sus resultados es una variable relativa y dependiente de una serie compleja de factores, es imposible establecer con absoluta seguridad cuál es el camino para llegar al éxito. Bajo estas consideraciones, los resultados de la presente investigación, se deben tomar como una propuesta metodológica que permite explorar en forma coherente y sistemática oportunidades de negocio. Este modelo es especialmente útil para las personas que no cuentan con tradición fl:\miliar, o experiencia como empresarios, o que su actividad laboral no ha sido estimulante para el desarrollo de habilidades empresariales. Es común encontrar que el éxito en el desarrollo de una nueva empresa, es la etapa superior de un proceso raclo-na~erñátlco, que se inicia mediante la generación de un buen número de ideas de negocio, prosigue con el enfoque de la oportunidad y continúa con la

pelo auxílio, disponibilidade e boa vontade nas etapas experimentais realizadas no Rio de Janeiro. Ao engenheiro Yukio Nishida. Ao técnico Carlos Rosa do laboratório Tricorrmat. À CAPES -Pró-Estratégia 2224/12 pelo apoio ao projeto. À FAPES pela bolsa de Mestrado.

Trafo merkezi tesis edilecek alanın toprak yapısını ve topraklama ağı döşenme uygunluğunu değerlendirmek için, birçok doğrultuda ve her doğrultuda bir çok noktada toprak özgül direnci ölçümleri yapılır. Bu toprak özgül direnci ölçümlerine göre, toprak katman yapısı yazılımsal olarak hazır paket program ve modüllerle belirlenerek ve Elektrik Tesislerinde Topraklamalar yönetmeliğine uygun olarak çok katmanlı toprak modeliyle topraklama ağı tasarlanır. Bu çalışmada, ekonomik olarak oldukça pahalı olan yurt dışı kaynaklı, hazır bir ticari paket program ya da modülleri kullanılmadan, toprak özgül direnci ölçümlerinden topraklama ağı tasarımında kullanmak üzere iki katmanlı toprak modeli parametreleri (𝜌 1 , 𝜌 2 , ℎ 1 ), Blum Blum Shub dizili Genetik Algoritmalar ile, IEEE standardına dayanarak yazılan Matlab koduyla bulunmuştur. Bu yönüyle çalışma özgündür ve ticari bir paket program kullanılmadığı için ekonomiktir. Ayrıca, toprağın özdirencinin derinlikle değişiminde, düşey elektrik sondaj çalışmalarının da uygunluğuna dikkat çekilmiştir.

During production of primary and secondary aluminium, various amounts of aluminium dross, a mixture consisting of molten aluminium metal and different oxide compounds, is skimmed per tonne of molten metal. In order to preserve the maximum aluminium content in hot dross for further extraction, it is necessary to cool the dross (e.g. by pressing) immediately after skimming. During pressing, the skimmed dross is transformed into so-called pressed skulls, convenient for storage, transport or further inhouse processing. Pressed skulls, which represent a valuable source of aluminium, are generally valued on a free-metal recovery basis. Therefore, it is important and useful to develop a method of fast and cost-effective non-destructive measurement of the free aluminium content in pressed skulls, independent of the technology of pressed skulls recycling. Following the theoretical considerations presented in this work, a practical industrial methodology was developed for non-destructive pred...

A model for diffusion-controlled spherical particle growth is presented and solved numerically, showing how, on cooling at sufficient rate from a given fraction solid, growth velocity first increases, and then decreases rapidly when solute fields of adjacent particles overlap. An approximate analytical solution for the spherical particle growth velocity is then developed and shown to be valid until the solute fields begin to overlap. A particle stability model is next presented, building on the above analytic solution. This model permits prediction of the maximum cooling rate at which a semi-solid slurry or reheated semi-solid billet can be cooled while still retaining the spherical growth morphology. The model shows that particle stability is favored by high particle density, high fraction solid and low cooling rate. The predictions of the stability model are found to be in good quantitative agreement with experimental data collected for Al-4.5wt%Cu alloy. Engineering applications of the results obtained are discussed. cooling, holding in the liquid-solid region, or solidifying and reheating into the liquidsolid region. It is now understood that if initial grain density is sufficiently high, growth can be perfectly spheroidal throughout the growth process, obviating the need for ripening of a dendritic structure. A concomitant advantage is that spheroids obtained in this way have none of the entrapped second phase present in most ripened dendrites. , From a practical point of view in semi-solid forming, the important basic issue is understanding the conditions of grain density, fraction solid and cooling rate that permit solidification in a fully non-dendritic, spheroidal mode. This work outlines those conditions; specifically comprising a modeling and experimental study of stability of the spheroidal particle interface in semi-solid Al-4.5wt%Cu alloy as a function of solid fraction and cooling rate. A spherical particle growth model was developed for semi-solid Al-4.5wt%Cu alloy. The model assumes equilibrium at the spherical solid-liquid interface, and no solid diffusion; local solidification velocity is limited by solute diffusion away from the interface. The model is hereafter referred to as the "Liquid Diffusion Controlled," or "LDC," model. It assumes growth of a spherical particle of radius R, located at the center of a spherical volume of radius R T . The value of R T represents the radius of a sphere which would occupy the same volume as will the fully solidified grain. Thus, overall solute contained within the volume element of radius R T is conserved, and the model permits determining the effect of solute field overlap on the particle growth velocity. Figure shows the model schematically, illustrating the solute profile in liquid

This study investigates the synthesis methods, structural properties, and potential applications of GNDCCS, emphasizing the interplay between graphene's exceptional electrical conductivity and nanodiamond's mechanical strength and thermal stability. Utilizing advanced techniques such as chemical vapor deposition (CVD) and high-pressure high-temperature (HPHT) methods, the research focuses on optimizing the composite's morphology and functional characteristics. Characterization through scanning electron microscopy (SEM), Raman spectroscopy, and X-ray diffraction (XRD) reveals a uniform spherical structure with enhanced surface area, thermal resistance, and tunable electrical properties. Applications explored include energy storage devices, advanced coatings, and biomedical systems, where the composite demonstrates improved performance metrics compared to standalone graphene or nanodiamond materials. The findings highlight the synergistic effects arising from the hybrid architecture, paving the way for advancements in nanomaterial science and multifunctional applications.

Surface modifications of metallic biomaterials can in great merit, improve the properties of the hard-tissue implants and in that way contribute to the success of the surgical implantation process. Coating deposition stands out as one of the many surface-modifying techniques that can be used to improve implant surface properties and, in turn, induce successful osseointegration. Deposition of the TiO2 layer on the surface of the metallic implants has a great potential to enhance not only their osseointegration ability but also their biocompatibility and corrosion resistance. In the present study, the possibility of successful deposition of the TiO2 layer on the surface of commercially pure titanium (CP-Ti), as the most commonly used metallic implant material, by spraying the colloidal nanoparticles aqueous solution in the electric discharge plasma at atmospheric pressure was investigated. To characterize the colloidal TiO2 nanoparticle solution, used for the coating deposition proces...

In order to study arc profile variation process with double-pulsed gas metal arc welding of aluminum alloy, a synchronous acquisition system and an analysis system have been established to acquire and analyze electrical signals and instantaneous images of arc profile. The results show that in double-pulse mode, the arc profile is matched with high-frequency pulse and thermal pulse. The droplet transfer mode always accompanies with high-frequency pulse cycle "one drop per pulse." The arc profile variation and droplet transfer in thermal base are lower than that in thermal peak. The serial-type arc is easier to occur in thermal base stage. High current density distribution at the top and bottom of traveling droplet leads to dazzling region. The variation of wire extension is influenced by thermal pulse frequency. The variance of arc size in thermal base is higher than in thermal peak, which leads arc force to vary with thermal pulse frequency. The variation of the droplet transfer and arc force in double pulse can improve the weld pool mobility.

The potential for creating local designed variations in microstructure has the potential to radically change how advanced and ultra-high strength steels are used in vehicle components. Such local changes in the microstructure offer the potential for tailored combinations of strength and ductility, both reducing vehicle weight and improving structural performance. This study addresses development of a new technology for creating such local changes in microstructure. The process, termed direct resistance heat treatment (DHRT) is analogous to resistance welding with in-situ tempering. Current pulses are used to first locally transform the microstructure (austenite to martensite reaction) then temper the martensitic microstructure to achieve desired levels of performance. Work here was done on a 1-mm thick 10B21 steel. Practices were first developed to achieve fully martensitic microstructures, and then combinations of temper currents and times were used to achieve differing final hardnesses. Thermal analyses taken from the resistance spot welding literature were used to validate the processing times employed for DRHT. These analyses showed that for the material studied, stable temperatures (during heating) could be achieved in about 50-ms, and the workpiece could effectively quenched in about 100-ms. Data was then curve fit to in-situ tempering models previously used for resistance spot welding. Mechanical evaluations showed that the locally hardened areas were effective for both diverting plastic deformation, and even developing cracks on notched specimens. It was noted that during DRHT, tempered zones were typically contained within the initial martensitic zones. These results are inconsistent with previous resistance spot welding work, and are believe related to geometry and differences between applying AC (previous study) and MFDC (current study) current.

The Na2O-MgO-CaO-FeO-Fe2O3-Al2O3-SiO2-P2O5 system is a basic oxide system for the Basic Oxygen Furnace (BOF) process as well as the hot metal dephosphorization process. Numerous experimental investigations on this oxide system are being carried out to find out an advanced process route for P removal from molten iron. In spite of their industrial importance, however, phase equilibria in oxide systems containing P2O5 have not been well investigated due to the complexity of their chemistry. No systematic thermodynamic modeling of these systems has been conducted to date, either. In order to meet the strong demands of steelmaking and other industries, new systematic thermodynamic modeling of the P2O5-containing oxide systems (Na2O-MgO-CaO-FeO-Fe2O3-Al2O3-SiO2-P2O5) and key phase diagram experiments have been carried out over the past years. In the present study, the results of the thermodynamic modeling of unary, binary and ternary P2O5-containing systems and the applications of the the...

Among ecological solders the SIAC (silver-indium-tin-copper) alloys seemed to be the promising because of their properties. In this paper the results of Ag-In-Sn-Cu electrical conductivity measurements are performed as well as polynomial regression of the same. These results are obtained for different temperature regimes and conditions.

Phase transition temperatures of selected ascast alloys from ternary Cu-Al-Ag system with overall compositions situated alongside vertical section with equal molar ratios of Ag and Cu were experimentally investigated using differential thermal analysis. Microstructures of the as-cast samples were analyzed using scanning electron microscopy with energy-dispersive spectrometry. Experimentally obtained results were compared with the results obtained by thermodynamic calculation of phase equilibria according to CALPHAD approach.

The provided document is a PDF of a Medium article titled "JACK SARFATTI'S V2 STAR FLEET ACADEMY COMES TO LIFE" by Felicity Harley, a writer focused on the human condition, psyche, and speculative topics. The article appears to be an extended interview or Q&A exchange where Harley poses questions to theoretical physicist Jack Sarfatti about unidentified anomalous phenomena (UAPs, often referred to as "tic tac" objects or UFOs), advanced propulsion systems, quantum mechanics, consciousness, and their intersections. Sarfatti provides a lengthy, detailed response, blending established physics principles with speculative theories, personal anecdotes, and proposals for future applications.

Fatigue crack growth rate (FCGR) tests with different load ratios and dwell-fatigue crack growth rate (DFCGR) tests with different dwell times were conducted at 750°C for Incoloy 800H. As the load ratio increases from 0.1 to 0.5, the crack growth rate increased and the transition ∆K value from region I to region II (Paris regime) shifted leftward. In DFCGR tests with dwell time of 10 and 30 seconds, the Paris regime started at relatively lower ∆K level and the crack grew much faster than in FCGR tests. However, the crack growth rates between the 10 sec and 30 sec dwell times were relatively similar. The higher crack growth rates in the DFCGR tests compared to FCGR tests was associated with the reduction of the M 23 C 6 precipitates in the vicinity of the advancing crack by the Cr depletion, suggesting the crack propagation in DFCGR conditions was environmentally assisted. The crack growth rate was controlled by trans-granular mode regardless of the dwell time because the dwell time was not enough to cause creep damage.

Since nanocrystalline WC-Co powder was produced over a decade ago, the sintering of nanocrystalline powders remains a technological challenge. The goal of sintering nanocrystalline powders is not only to achieve full densification but also to retain nanocrystalline grain sizes. This is difficult because of rapid grain growth at high temperatures. Previous studies on the sintering of nanocrystalline WC-Co have shown that grains grow rapidly during the early stage of sintering. But there are few studies on the mechanisms of grain growth and densification during this stage. This paper presents the results of an experimental investigation on grain growth and densification of nanocrystalline WC-Co powders during heat-up at equilibrium solid-state temperatures. The results have shown that nanocrystalline WC grains grow rapidly during this period concurrently with rapid densification. The rapid densification and grain growth are partially attributed to the surface energy anisotropy of tungsten carbide. The effects of vanadium carbide on grain growth at solid state during heat-up are also discussed.

The core of an earth dam plays a crucial role in sealing the dam and mitigating the possibility of hydraulic fracturing. This research aims to investigate the phenomenon of hydraulic fracturing and the effect of the dimensions and cross-sectional shape of the clay core. Hydraulic fracture in the middle of the core and on the upstream side of the core has been investigated for two types of lowplasticity clay (CL) and high-plasticityclay (CH). The end of construction, initial dewatering, and steady-state seepage, as well as the stages of dam construction, have also been considered in the modeling. The results show that CL is the critical soil and CH is the selected soil for the dam's core. Also, the possibility of hydraulic fracture in thicker cores and at the bottom of the core was investigated. The results showed that the criteria of Fukushima and Ghanbari yielded the most optimistic and conservative data, respectively. According to the criteria used in this research, CH soil is safe from hydraulic fracturing, and the possibility of hydraulic fracturing for critical soil (CL) downstream of the dam core was found to be probable.

A systematic study of the microstructural response of conventionally cast IN 738 and single crystal CMSX 486 superalloys during linear friction welding was performed. The results revealed that, aside from a significant liquation of various phases that occurred during joining, continuous oxide films formed on the weld lines in both materials. The weld line oxides consisted of aluminum-rich and hafnium-base oxides in IN 738 and CMSX 486 superalloys, respectively, which can be deleterious to the mechanical properties of the weld joint. Gleeble thermo-mechanical simulation showed that the oxides were produced by the oxidation of some liquid exposed to atmospheric oxygen at the mating surfaces of the work pieces. A practicable method of eliminating liquid phase oxidation during linear friction welding of nickel-base superalloys is discussed.

The interaction of different alloying elements has a significant impact on the mechanical and microstructural properties of steel products due to the thermodynamic and kinetic effect. This article presents a statistically developed and validated model for austenite decomposition during cooling, based on a set of experimental continuous cooling transformation diagrams available in literature. In the model, two-way interactions of the alloying elements are included as add-on terms, and the procedure for the analysis ensures there is no overfitting. The model can be used to predict phase transformation temperatures and critical cooling rates for the formation of polygonal ferrite, bainite or martensite for the production of steel.

We present a computational method for calculating the phase transformation start for arbitrary cooling paths and for different steel compositions after thermomechanical treatments. We apply the method to quantitatively estimate how much austenite deformation and how many different alloying elements affect the transformation start at different temperatures. The calculations are done for recrystallized steel as well as strain hardened steel, and the results are compared. The method is parameterized using continuous cooling transformation (CCT) data as an input, and it can be easily adapted for different thermomechanical treatments when corresponding CCT data is available. The analysis can also be used to obtain estimates for the range of values for parameters in more detailed microstructure models.

The results of research on the leaching process of complex sulphide-barite ore were presented in this paper. The leaching process was carried out in a laboratory autoclave by ferric chloride solution. Considering that those minerals are represented in complex structural-textural relationships, it is not possible to extract lead, zinc and copper minerals from ore by flotation methods. The obtained results confirmed possibility of the ore processing directly, by chemical methods. The effect of temperature, time and oxygen partial pressure on the lead, zinc and copper dissolution was studied. The maximal leaching degree was achieved at 100 °C and amount of 91.5 % for Pb, 96.1 % for Zn and 60.7 % for Cu). Leaching at temperatures above 100 °C is impractical.

In this paper, the microstructure of Cu82.3Al8.3Mn9.4 (in wt. %) shape memory alloy after hot and cold rolling was investigated. The Cu82.3Al8.3Mn9.4 alloy was produced by a vertical continuous casting method in the form a cylinder rod of 8 mm in diameter. After the casting, hot and cold rolling was performed. By hot rolling a strip with a thickness of 1.75 mm was obtained, while by cold rolling a strip with a thickness of 1.02 mm was produced. After the rolling process, heat treatment was performed. Heat treatment was carried out by solution annealing at 900 °C held for 30 minutes and water quenched immediately after heating. The microstructure characterization of the investigated alloy was carried out by optical microscopy (OM), scanning electron microscopy (SEM) equipped with a device for energy dispersive spectroscopy (EDS). Phase transformation temperatures and fusion enthalpies were determined by differential scanning calorimetry (DSC) method. The homogenous martensite microst...

He is currently professor and researcher at the UTN-FRSN, Ar-gentina. His work area is related with hydrogen embrittlement of steels and its alloys. Currently he is working on his PhD in engineering at the Physical Metallurgy Laboratory of the UTN-FRSN.

During their operation, modern aircraft engine components are subjected to increasingly demanding operating conditions, especially the high pressure turbine (HPT) blades. Such conditions cause these parts to undergo different types of time-dependent degradation, one of which is creep. A model using the finite element method (FEM) was developed, in order to be able to predict the creep behaviour of HPT blades. Flight data records (FDR) for a specific aircraft, provided by a commercial aviation company, were used to obtain thermal and mechanical data for three different flight cycles. In order to create the 3D model needed for the FEM analysis, a HPT blade scrap was scanned, and its chemical composition and material properties were obtained. The data that was gathered was fed into the FEM model and different simulations were run, first with a simplified 3D rectangular block shape, in order to better establish the model, and then with the real 3D mesh obtained from the blade scrap. The overall expected behaviour in terms of displacement was observed, in particular at the trailing edge of the blade. Therefore such a model can be useful in the goal of predicting turbine blade life, given a set of FDR data.

In 2006 the Australian steel industry and CSIRO initiated an R&D program to reduce the industry’s net greenhouse emission by at least 50%. Given that most of the CO2 emissions in steel production occur during the reduction of iron ore to hot metal through use of coal and coke, a key focus of this program has been to substitute these with renewable carbon (charcoal) sourced from sustainable sources such as plantations of biomass species. Another key component of the program has been to recover the waste heat from molten slags and produce a by-product that could be substituted for Portland cement.

The present study focuses on the metallurgical and corrosion characterization of post weld heat treated duplex stainless steel joints. After friction welding, it was confirmed that there is an increase in ferrite content at weld interface due to dynamic recrystallization. This caused the weldments prone to pitting corrosion attack. Hence the post weld heat treatments were performed at three temperatures 1080[Formula: see text]C, 1150[Formula: see text]C and 1200[Formula: see text]C with 15[Formula: see text]min of aging time. This was followed by water and oil quenching. The volume fraction of ferrite to austenite ratio was balanced and highest pit nucleation resistance were achieved after PWHT at 1080[Formula: see text]C followed by water quench and at 1150[Formula: see text]C followed by oil quench. This had happened exactly at parameter set containing heating pressure (HP):40 heating time (HT):4 upsetting pressure (UP):80 upsetting time (UP):2 (experiment no. 5). Dual phase prese...

A technological scheme for copper slag processing is proposed. It comprises 5 stages, namely: (i) air oxidation of the copper slag at a temperature above 800 o C for 2 h; (ii) hydrothermal treatment of the oxidized slag with sodium hydroxide solution (140 g/l) at 190 o C for 3 h; (iii) separation of the solid from the liquid phase by hot filtration; (iv) gel formation through hydrolysis of the liquid silicate phase by changing pH; (v) obtaining of amorphous SiO 2 (silica gel) by drying at 80 o C. The processes used for slag manipulation were elucidated and optimized for silicon extraction. It was established that the increase in the oxygen partial pressure in the oxidizing gas does not change the mechanism nor significantly intensifies the oxidizing process. A decisive factor for the extraction of SiO 2 during hydrothermal treatment was the concentration of NaOH. Its increase from 60 to 140 g/l reduced the amount of residual SiO 2 more than half and significantly decreased the formation of analcime (NaAlSi 2 O 6 .H 2 O) in the solid phase. Hydrolysis of the liquid silicate phase by changing pH is an appropriate process for gel formation.