Exploring new Boundary Conditions for N=(1,1)\mathcal{N}=(1,1) Extended Higher Spin AdS3AdS_3 Supergravity

In this paper, we present a candidate for $\mathcal{N}=(1,1)$ extended higher - spin $AdS_3$ supergravity with the most general boundary conditions discussed by Grumiller and Riegler recently. We show that the asymptotic symmetry algebra consists of two copies of the $\mathfrak{osp}(3|2)_k$ affine algebra in the presence of the most general boundary conditions.Furthermore, we impose some certain restrictions on gauge fields on the most general boundary conditions and that leads us to the supersymmetric extension of the Brown - Henneaux boundary conditions. We eventually see that the asymptotic symmetry algebra reduces to two copies of the $\mathcal{SW}(\frac{3}{2},2)$ algebra for $\mathcal{N}=(1,1)$ extended higher - spin supergravity.Comment: 25 pages, no figures, LaTeX file, Sec.4 added, added references, a few typos correcte

Vertex Operator Extension of Casimir W A(N) Algebras

We give an extension of Casimir of Casimir $\cal{WA_N}$ algebras including a vertex operator which depends on non-simple roots of $A_{N-1}$.Comment: 7 pages,no figures,TeX file,(to appear in Mod.Phys.Lett.A

Miura-Like Free Field Realization Of Fermionic Casimir WB(3) Algebras

Starting from the well-known quantum Miura-like transformation for the non simply-laced Lie algebras B(3),we give an explicit construction of the Casimir WB(3) algebras.We reserve the notation WB(N) for the Casimir W algebras of type W(2,4,6,...,2N,N+1/2) which contains one fermionic field. It is seen that WB(3) algebra is closed an associative for all values of the central element c.Comment: 7 pages,no figures,TeX fil

Noncontact lateral-force gradient measurement on Si(111)-7×7 surface with small-amplitude off-resonance atomic force microscopy

In this work, the authors report on a quantitative investigation of lateral-force gradient and lateral force between a tungsten tip and Si(111)-(7×7) surface using combined noncontact lateral-force microscopy and scanning tunneling microscopy. Simultaneous lateral-force gradient and scanning tunneling microscopy images of single and multiatomic step are obtained. In our measurement, tunnel current is used as feedback. The lateral-stiffness contrast has been observed to be 2.5 N/m at a single atomic step, in contrast to 13 N/m at a multiatomic step on Si (111) surface. They also carried out a series of lateral stiffness-distance spectroscopy, which show a sharp increase in tip-surface interaction stiffness as the sample is approached toward the surface

Fresh and Hardened Properties of Cementitious Composites Incorporating Firebrick Powder from Construction and Demolition Waste

Firebricks are generally used in furnace basins where glass, ceramics, and cement are produced. Firebricks have an important place in construction and demolition waste (CDW). However, there is a limited understanding of the effects on fresh and hardened state properties of cementitious composites. This study investigates the mechanical, physical, and microstructural properties of cementitious composites incorporating firebrick powder (FBP) from CDW. In this regard, the FBP was used at 5, 10, 15, 20, and 25% replacement ratio by weight of cement to produce cementitious composites. The consistency, setting characteristics, and 3, 7, and 28 days compressive and flexural strength tests of produced cementitious composites were performed. In addition, ultrasonic pulse velocity, water absorption, porosity, unit weight, and microstructure analysis of cementitious composites were conducted. As a result, the 28-day compressive strength of the cementitious composite mortars containing up to 10% firebrick powder remained above 42.5 MPa. The flow diameters increased significantly with the increase of the FBP. Therefore, it has been determined that the FBP can be used up to 10% in cementitious composites that require load-bearing properties. However, FBP might be used up to 25% in some cases. Using waste FBP instead of cement would reduce the amount of cement used and lower the cost of producing cementitious composites

Atomic scale investigation of clean and epi-grown Si(001) surfaces using scanning tunneling microscopy

Ankara : Department of Physics and the Institute of Engineering and Science of Bilkent University, 1996.Thesis (Master's) -- Bilkent University, 1996.Includes bibliographical references leaves 60-65.III ( liis lİK'.sis, cl('aii and <‘|)i-grovvn Si(üü 1 )(2 x I) suriacc's ai(' aııalysc'd by Scanning 'I'nnnc'ling Micioscopy (S'l'M). 'I'lu' S'l'lM and IMlra High Vacuum SysicMii (UH V) in which thc' microscope is installed, are dc'scrihed. A brief history of the studic's on the' rc'coristruction and ruudamental leaturc's of the Si(OOl) surface is also given, f'irst, the sample and tip |)rc'paration technicpies were optimized. Sample prc'paration method, which inclndc;s both e.v situ chemical and in situ heating clc'aning procedures, was found not to give routinely the clc'an and atomically flat surfaces, because of the criticality of the' temperature values used during heat treatments. The monoatomic steps, dimcM' rows, delects such as missing dimer and dimer groups, were observed on clc'aii Si(OOl) surfaces. Double height step formation due to contamination was also detc'cted on a few sa.m|)l('s. Buckling of dimers which is bcdievcxl to bc' due mainly to either the high dc'fect density or tip-surface interaction, was observeebon one sample. Si and Ce were grown epita.xially on the silicon substrate, with 0.1 I ML and 0.2 ML coverages, respectively. 'Flie Si growth on Si(OOl) was found to occur as island lomiation because of the low substrate teruperature (~ .’lOO °('). Strong shape anisotropy and diilusional anistropy in the grovvtii have been observed. On tlie otiu'r hand, th(‘ large coverage of Ce on Si(OOl) at a relativ('ly high substrate t('m|)('ra.tui(' ( ~ hOO °('), ar(' r('sult('d in step How growth ratlu'r than individual island rormatioii on the t('irac('s.Özer, H ÖzgürM.S

Exuberant Behaviour in The Istanbul Housing Market Before and During The Time of The COVID-19 Pandemic: Evidence from The Aggregate and Disaggregate Levels

We study mildly explosive behaviour in house prices in Istanbul at both aggregate and disaggregate levels via GSADF tests. In contrast to previous studies, our results suggest multiple episodes of price exuberance in Istanbul and most districts. Most boroughs synchronically experienced explosive house prices in 2014–2015; and more powerfully during the last episodes of COVID-19. We also show that financial variables, including low mortgage interest rates and high stock prices, increased the probability of explosiveness

Determination of compressive strength of perlite-containing slag-based geopolymers and its prediction using artificial neural network and regression-based methods

This study has two main objectives: (i) to investigate the parameters affecting the compressive strength (CS) of perlite-containing slag-based geopolymers and (ii) to predict the CS values obtained from experimental studies. In this regard, 540 cubic geopolymer samples incorporating different raw perlite powder (RPP) replacement ratios, different sodium hydroxide (NaOH) molarity, different curing time, and different curing temperatures for a total of 180 mixture groups were produced and their CS results were experimentally determined. Then conventional regression analysis (CRA), multivariate adaptive regression splines (MARS), and TreeNet methods, as well as artificial neural network (ANN) methods, were used to predict the CS results of geopolymers using this experimentally obtained data set. Root mean square error (RMSE), mean absolute error (MAE), scatter index (SI) and Nash-Sutcliffe (NS) performance statistics were used to evaluate the CS prediction capabilities of the methods. As a result, it was determined that the optimum molarity, curing time, and curing temperature were 14 M, 24 h, and 110 celcius, respectively and 48 h of heat curing did not have a significant effect on increasing the CS of the geopolymers. The highest performances in regression-based models were obtained from the MARS method. However, the ANN method showed higher prediction performance than the regression-based methods. Considering the RMSE values, it was seen that the ANN method made improvements by 24.7, 2.1, and 13.7 %, respectively, compared to the MARS method for training, validation, and test sets