Determination of component ratio in a historic lime-based mortar

Vápenná malta je nejčastěji používaným materiálem při obnově památek, kdy je využíváno napodobení původního složení. Pokusů o napodobení historické vápenné malty tak bylo již mnoho, ale stále ještě mnoho aspektů tohoto tématu zůstává neprobádáno. Historické malty se od moderních malt liší a jsou s historickými materiály kompatibilnější. Omezeními pro zdárné využití v památkové péči jsou mezigenerační ztráta teoretických i praktických znalostí a nedostatek technicky zaměřených archivních pramenů. Za účelem napodobení postupu je nutné pochopit charakter pojiva a plniva, který je daný zejména druhem pojiva, druhem a velikostním rozložením zrn kameniva a jejich poměrem mísení. Použití testů charakterizace je hodnoceno v kontextu informací potřebných pro úspěšnou formulaci opravné malty pro konzervační praxi. Diplomová práce se soustředí na určení poměru pojiva ku kamenivu historické vápenné malty včetně analýz vlastností pojivové matrice. Pro provedení této studie byly vybrány čtyři analytické metody a jejich výstupy byly analyzovány s cílem ověřit spolehlivost těchto metod pro konzervační praxi. Metody jsou založeny na laboratorní chemické analýze, optické mikroskopii, termické analýze a skenovací elektronové mikroskopii vybavené energiově disperzním spektrometrem. Vzorky malty byly odebrány z pěti různých typů podlah, které byly vytvořeny jako kopie pro účely památkové ochrany. Zkoumání poměru pojiva ku kamenivu bylo diskutováno ve srovnání s původním poměrem míseni a výsledky z analytických metod byly detailně zhodnoceny.Lime-based mortar is the most commonly used material in restoring heritage structures by imitating the original one. Therefore, there has been a great number of research and practical attempts to replicate the historic lime-based mortars, but still many aspects of this subject are unexplored. Historic mortars are different from the modern ones and are more compatible with historical substrates. The limitations in the successful use in building conservation are the lost practical and theoretical information between the generation and minimum availability of technically oriented written records. In order to imitate the procedure, it is necessary to understand the character of binder and aggregate that is governed mainly by the type of binder, type and grain size distribution of aggregates and their mix proportions. The use of characterisation testing is considered in the context of data needed to have a successful formulation of a repair mortar for conservation practice. The dissertation is centralised on the determination of binder to aggregate ratio of historic lime-based mortar including analysing the properties of binder matrix. Four analytical methods were selected to carry out the study and their outputs were analysed to check the reliability of these methods for conservation practice. The methods are laboratory based chemical analysis, optical microscopy, thermal analysis and scanning electron microscopy with energy dispersed spectrometric analyser. Mortar samples were collected from five different types of flooring, which had been recreated for conservation purposes. The examination of binder to aggregate ratio was discussed in comparison with the reference of original mortar mixing ratios and the results from the analytical methods were reviewed

A Constant Factor Approximation for Capacitated Min-Max Tree Cover

Given a graph G = (V,E) with non-negative real edge lengths and an integer parameter k, the (uncapacitated) Min-Max Tree Cover problem seeks to find a set of at most k trees which together span V and each tree is a subgraph of G. The objective is to minimize the maximum length among all the trees. In this paper, we consider a capacitated generalization of the above and give the first constant factor approximation algorithm. In the capacitated version, there is a hard uniform capacity (?) on the number of vertices a tree can cover. Our result extends to the rooted version of the problem, where we are given a set of k root vertices, R and each of the covering trees is required to include a distinct vertex in R as the root. Prior to our work, the only result known was a (2k-1)-approximation algorithm for the special case when the total number of vertices in the graph is k? [Guttmann-Beck and Hassin, J. of Algorithms, 1997]. Our technique circumvents the difficulty of using the minimum spanning tree of the graph as a lower bound, which is standard for the uncapacitated version of the problem [Even et al.,OR Letters 2004] [Khani et al.,Algorithmica 2010]. Instead, we use Steiner trees that cover ? vertices along with an iterative refinement procedure that ensures that the output trees have low cost and the vertices are well distributed among the trees

Role of plasminogen activator inhibitor type 1 (PAI-1) in PCOS patient

Background: There has been few studies done demonstrating elevated level of PAI-1 in women with Polycystic Ovarian Syndrome (PCOS). PAI-1 has been associated with insulin resistance, obesity, anovulatory infertility, increased risk of cardiovascular disease in PCOS patient. The objective of the study was to find out the plasma level of PAI-1 in PCOS and compare with healthy age matched control. To correlate PAI-1 with various demographic, anthropometric, biochemical and hormonal parameters in PCOS patient and specific relation of PAI-1 with the insulin resistance, obesity, hyperandrogenemia.Methods: A prospective case control study was carried out in 50 patients having PCOS (fulfilling Rotterdam Criteria, 2003). 25 healthy age matched control were taken. Blood samples were taken for estimation of fasting glucose, fasting insulin, lipid profile, LH, FSH, Prolactin, Testosterone, insulin sensitive indices (HOMA-IR, glucose: insulin ratio). Plasma level of PAI-1 was estimated with Human ELISA invitorgen kit. The data were statistically analysed with SPSS 16.0 version (student T test, Pearson ranked correlation coefficient, linear regression analysis was applied) and PAI-1 was correlated with various parameters.Results: Mean level of PAI-1 was significantly raised in PCOS patient (893.36±234.97) pg/mL than in control (259.68±97.75) pg/mL (p<0.001). PAI-1 significantly correlated with insulin resistance, obesity; that is; PAI-1 significantly correlated with BMI (r=0.557; p<0.001), waist: hip ratio (r=0.550; p<0.001), fasting glucose (r=0.429; p=0.002), fasting insulin (r=0.357; p=0.001), triglyceride (r=0.492; p=0.000), LDL (r=0.604; p=0.001), HOMA-IR (r=0.467; p=0.001). On regression analysis LDL, fasting insulin, HOMA-IR altogether explained 54.9% of total variability of PAI-1.Conclusions: Plasma level of PAI-1 is elevated in PCOS patient and it is significantly correlated with insulin resistance and obesity