Preparation of synthetic slag in the lab resembling industrial blast furnace slag and study of its flow characteristics

A study of the flow characteristics of blast furnace slag is important to record the softening and melting phenomena in blast furnace which greatly influence the extent and location of the cohesive zone having a direct say on the blast furnace operation, quality of hot metal and the coke consumption. In the present work, a noble technique (heating microscope) is adopted to determine the flow characteristics of synthetic slags with high alumina content resembling different indian blast furnace slags . It is also seen that the characteristics temperature are altered with the alteration of C/S ratio and also the MgO and TiO2 content of the blast furnace slag

Study of Kinetics Involved in Oxidation of Nonferrous Metal Sulphides

In the present investigation, an attempt has been done to study the simultaneous effects of the major processing variables on the extent of oxidation of commercially pure sphalerite ore pellets. These process variables taken into consideration were time and temperature. The oxidation was carried inside a muffle furnace where there was mild oxidation in the presence of atmospheric air. The pellets were charged for roasting inside the furnace in a graphite crucible. This process of roasting was carried out at four temperatures 7500 C, 8000 C , 8500 C and 9000 C .The project goal is to compare the oxidation or roasting at different temperature and time. At all instance of comparison one of the parameter was kept constant. The percentage (degree) of oxidation of sphalerite pellets was calculated at 15, 30, 45 and60 minutes, after the furnace reached the predetermined oxidation temperature. The experiments were statistically designed such that the effect of each variable can be quantitatively assessed and compared. The results showed that, temperatures above 8500C, time remaining constant, with the increase in temperature there is increase in the rate of oxidation (roasting) of sphalerite ore pellets. Further more for a constant temperature with the increase in time of exposure, rate of oxidation of Sphalerite (ZnS) pellets increases. This is valid for temperature range above 8500C. Another observation was made that temperature remaining constant, the rate of oxidation of Sphalerite (ZnS) ore pellets increases with time of exposure to attain a maximum limit than suddenly decreases followed by increment in the rate again. This observation was made in the temperature range of less than 8000C

Designing terry fabric for improved serviceability

Various terry fabrics (cotton) having different constructional parameters have been designed and the effect of washingtreatment on water absorbency, surface characteristics and compression characteristics are studied. To establish the optimumloop length and loop density of terry fabrics at which they can withstand maximum number of washing cycles withoutaffecting water absorbency, surface characteristics and compression characteristics, terry fabrics having the same yarn andfabric parameters are washed under industrial conditions for 10 washing cycles. After each cycle, the rate of waterabsorption, total amount of water absorbed, surface characteristics and compression characteristics are evaluated bygravimetric absorbency testing system, image analysis techniques and KES-FB-3 testing system respectively. Another groupof cotton terry fabrics having different loop length and loop density have been studied to optimise these two important fabricparameters to increase the life of fabric. It is observed that the rate of water absorption, the total amount of water absorbedand the surface characteristics improve with increase in washing cycle, but after 8th washing cycle these parameters startdeteriorating. Maximum possible loop density and loop length of 15 - 17 mm give maximum life of terry fabric i.e. thefabric can perform well even after 10 washing cycles. This study will certainly help in increasing the life of terry fabric,developing high quality towel fabric by providing information on absorbency, surface characteristics and compressioncharacteristics of fabric before and after washing along with the values of loop length and loop density

Performance of terry towel

In this paper, a critical review of the evolved theories and mechanisms of water absorption in terry fabric has been reported along with the key factors to improve the water absorption. Critical analysis of all the information helps to understand and choose the most realistic theory and mechanism of water absorption of terry fabric which will be helpful in designing the most absorbent terry fabric. Both dynamic and static water absorbency along with the initial time lag immerse to be the equally important attributes of the water absorbency performance of terry fabrics. High loop shape factor is the key to improve the absorbency behaviour of the terry fabric. Study of cross-section images of different fabric is the original work of the authors for supporting the concluding theory, mechanism and results

Factorization of large tetra and penta prime numbers on IBM quantum processor

The factorization of a large digit integer in polynomial time is a challenging computational task to decipher. The exponential growth of computation can be alleviated if the factorization problem is changed to an optimization problem with the quantum computation process with the generalized Grover's algorithm and a suitable analytic algebra. In this article, the generalized Grover's protocol is used to amplify the amplitude of the required states and, in turn, help in the execution of the quantum factorization of tetra and penta primes as a proof of concept for distinct integers, including 875, 1269636549803, and 4375 using 3 and 4 qubits of IBMQ Perth (7-qubit processor). The fidelity of quantum factorization with the IBMQ Perth qubits was near unity.Comment: 12 pages, 6 figure

Anisotropic ferromagnetism in carbon doped zinc oxide from first-principles studies

A density functional theory study of substitutional carbon impurities in ZnO has been performed, using both the generalized gradient approximation (GGA) and a hybrid functional (HSE06) as exchange-correlation functional. It is found that the non-spinpolarized C$_\mathrm{Zn}$ impurity is under almost all conditions thermodynamically more stable than the C$_\mathrm{O}$ impurity which has a magnetic moment of $2\mu_{\mathrm{B}}$, with the exception of very O-poor and C-rich conditions. This explains the experimental difficulties in sample preparation in order to realize $d^{0}$-ferromagnetism in C-doped ZnO. From GGA calculations with large 96-atom supercells, we conclude that two C$_\mathrm{O}$-C$_\mathrm{O}$ impurities in ZnO interact ferromagnetically, but the interaction is found to be short-ranged and anisotropic, much stronger within the hexagonal $ab$-plane of wurtzite ZnO than along the c-axis. This layered ferromagnetism is attributed to the anisotropy of the dispersion of carbon impurity bands near the Fermi level for C$_{\mathrm{O}}$ impurities in ZnO. From the calculated results, we derive that a C$_{\mathrm{O}}$ concentration between 2% and 6% should be optimal to achieve $d^{0}$-ferromagnetism in C-doped ZnO.Comment: 9 pages, 7 figure

Economics and yield performance of some short duration fruit and medicinal crops under agrisilvicultural system in rainfed uplands of Odisha

A field experiment was conducted during 2011-12 in an agrisilvicultural system consisting of two silvicultural species viz. Acacia mangium (mangium) and Gmelina arborea (gamhar) planted in 2000 at a spacing of 8m x 2m and four agricultural crops viz. Ananas comosus (pineapple), Aloe vera (aloevera), Andrographis paniculata(kalmegh) and Curcuma amada (mangoginger) were raised in the 1st week of July, 2011.The maximum volume increment were achieved by mangium with pineapple (16.53 m3/ha). Pineapple also registered the maximum fruit yield of 9981Kgha-1 under mangium and minimum under gamhar (9106 Kgha-1). The fresh leave yield of aloevera (8635Kg ha-1) was maximum under mangium which is statistically at par with gamhar. However, kalmegh recorded maximum dry plant yield of 1239 Kgha-1 under open condition followed by 1072 Kgha-1 under gamhar and 823 Kgha-1 under mangium. Similarly, mangoginger exhibited maximum rhizome yield of 3300 Kgha-1 under open condition followed by 1979 Kgha-1 under gamhar and 1597 Kgha-1 under mangium. The trend of crop yield under both the trees and open condition was: Pineapple >Aloevera>Mangoginger>Kalmegh. A. mangium with pineapple based agrisilvicultural system recorded the highest gross return, net return and BCR as compared to other agrisilvicultural systems and sole crops

Characterization of shape and dimensional accuracy of incrementally formed titanium sheet parts with intermediate curvatures between two feature types

Single point incremental forming (SPIF) is a relatively new manufacturing process that has been recently used to form medical grade titanium sheets for implant devices. However, one limitation of the SPIF process may be characterized by dimensional inaccuracies of the final part as compared with the original designed part model. Elimination of these inaccuracies is critical to forming medical implants to meet required tolerances. Prior work on accuracy characterization has shown that feature behavior is important in predicting accuracy. In this study, a set of basic geometric shapes consisting of ruled and freeform features were formed using SPIF to characterize the dimensional inaccuracies of grade 1 titanium sheet parts. Response surface functions using multivariate adaptive regression splines (MARS) are then generated to model the deviations at individual vertices of the STL model of the part as a function of geometric shape parameters such as curvature, depth, distance to feature borders, wall angle, etc. The generated response functions are further used to predict dimensional deviations in a specific clinical implant case where the curvatures in the part lie between that of ruled features and freeform features. It is shown that a mixed-MARS response surface model using a weighted average of the ruled and freeform surface models can be used for such a case to improve the mean prediction accuracy within ±0.5 mm. The predicted deviations show a reasonable match with the actual formed shape for the implant case and are used to generate optimized tool paths for minimized shape and dimensional inaccuracy. Further, an implant part is then made using the accuracy characterization functions for improved accuracy. The results show an improvement in shape and dimensional accuracy of incrementally formed titanium medical implants

Fragmentation of a Circular Disc by Impact on a Frictionless Plate

The break-up of a two-dimensional circular disc by normal and oblique impact on a hard frictionless plate is investigated by molecular dynamics simulations. The disc is composed of numerous unbreakable randomly shaped convex polygons connected together by simple elastic beams that break when bent or stretched beyond a certain limit. It is found that for both normal and oblique impacts the crack patterns are the same and depend solely on the normal component of the impact velocity. Analysing the pattern of breakage, amount of damage, fragment masses and velocities, we show the existence of a critical velocity which separates two regimes of the impact process: below the critical point only a damage cone is formed at the impact site (damage), cleaving of the particle occurs at the critical point, while above the critical velocity the disc breaks into several pieces (fragmentation). In the limit of very high impact velocities the disc suffers complete disintegration (shattering) into many small fragments. In agreement with experimental results, fragment masses are found to follow the Gates-Gaudin-Schuhmann distribution (power law) with an exponent independent of the velocity and angle of impact. The velocity distribution of fragments exhibit an interesting anomalous scaling behavior when changing the impact velocity and the size of the disc.Comment: submitted to J. Phys: Condensed Matter special issue on Granular Medi