chemical hardness (), absolute electronegativity (), and electrophilicity () have importantapplications in inorganic chemistry. these concepts are defined quantitatively as � � �� � ����,� � �� � ����, � � ������where i is the ionization energy and a is the electron affinity. in thisstudy, graphical method was used to see the relation of electron configuration with chemicalhardness, absolute...

The aim of this study is to analyze the properties Paulownia tomentosa x elongata plantation wood from Serbia, considering influence stem height (0 1 m and 4.5 6 above soil level—height spot) radial position pith bark (in core, near bark, in between these zones—cross-section spot). results show that most are improved when samples were taken upper parts tree (height spot (cross-section mean dens...

introduction: we aimed to compare apical canal transportation of extracted teeth and two types of simulated resin blocks. materials and methods: mesiobuccal root of extracted maxillary molars, high hardness simulated resin blocks (knoop hardness=40) and low hardness simulated resin blocks (knoop hardness=22) were prepared with k-files using step-back technique (n=15 canals in each group). doubl...

BACKGROUND Bulk-fill resin composite has been introduced, their manufacturers claimed that they can be applied in bulks of 4mm, without necessitating a prolonged curing time, or a light curing unit with increased irradiance. Thus this study was conducted to evaluate the effect of resin thickness, and curing time on the micro-hardness of two bulk -fill resin composites; Tetric Evo-Ceram [TE], an...

The aim of this study was to compare objective and subjective hardness of selected common foods with a wax cube used as a test item in a mixing ability test. Objective hardness was determined for 11 foods (cream cheese, boiled fish paste, boiled beef, apple, raw carrot, peanut, soft/hard rice cracker, jelly, plain chocolate and chewing gum) and the wax cube. Peak force (N) to compress each item...

OBJECTIVE The aim of this study was to evaluate the effect of multiple layers of an infection control barrier on the micro-hardness of a composite resin. MATERIAL AND METHODS One, two, four, and eight layers of an infection control barrier were used to cover the light guides of a high-power light emitting diode (LeD) light curing unit (LCU) and a low-power halogen LCU. The composite specimens...

The hardness-based regulatory approach for Cu prescribes an extrapolation of the toxicity-versus-hardness relationship to low hardness (< or =50 mg/L as CaCO3). Hence, the objective of the present research was to evaluate the influences of water quality on acute Cu toxicity to larval fathead minnow (Pimephales promelas) in low-hardness surface waters. Seasonal water sampling was conducted at 24...