Bending diamonds by femtosecond laser ablation

We present a new method based on femtosecond laser ablation for the fabrication of statically bent diamond crystals. Using this method, curvature radii of 1 m can easily be achieved, and the curvature obtained is very uniform. Since diamond is extremely tolerant to high radiation doses, partly due to its densely packed lattice, such bent crystals are optimal solutions for crystal-based collimation and/or extraction. Furthermore, using interlaced ablation on both sides, the technique opens for the possibility of constructing a crystalline undulator based on the best material known, to approach the enormous beam densities required for lasing operation of such a device.     

Microstructure,physical and mechanical properties of mortar–rubber aggregates mixtures

This work focuses on the feasibility of reusing and valorising rubber aggregates from shredded worn tyres in cement composites. Our purpose is to study the influence of both microstructures of matrix and of interfacial transition zone (ITZ) on mechanical properties of mortar–rubber aggregates mixtures. The same volume of rubber aggregates substituted volume fractions of sand. Volume ratios of rubber aggregates were ranged from 0% to 50%. Micro structural morphology of various samples was observed by means of scanning electron microscopy (SEM). The matrix porosity and the evolution of hydration products (CSH, CaOH₂, CaCO₃) were estimated for specimens that had been curing for 28 days at constant temperature and constant relative humidity. An energy dispersive X-ray analyser and X-ray diffraction were used together with SEM in order to quantify these results.     

Halogen bonding: Recent advances

Halogen bonding (XB), as a directional interaction between covalently bound halogen atoms (XB donor) and Lewis bases (A, XB acceptor), has been recently intensively investigated as a powerful tool in crystal engineering. After a short review on the origin and general features of halogen bonding, current developments towards (i) the elaboration of three-dimensional networks, (ii) the interaction with anionic XB acceptors, (iii) its identification in biological systems and (iv) the formation of liquid crystal phases will be described. Theoretical analyses, statistical studies and experimental electron density determinations converge to describe halogen bonding as a relatively weak structure directing tool, when compared with hydrogen bonding. However, when the halogen atom is strongly activated as in iodoperfluorinated molecules or cationic aromatic systems can halogen bonding act as an efficient and reliable structure directing tool.     

Do personality problems improve during psychodynamic supportive–expressive psychotherapy? Secondary outcome results from a randomized controlled trial for psychiatric outpatients with personality disorders.

Studies involving patients with personality disorders (PDs) have not focused on improvement of core aspects of the PD. The authors examined changes in quality of object relations, interpersonal problems, psychological mindedness, and personality traits in a sample of 156 patients with Diagnostic and Statistical Manual of Mental Disorders (4th ed.) PD diagnoses being randomized to either manualized or nonmanualized dynamic psychotherapy. Effect sizes adjusted for symptomatic change and reliable change indices were calculated. The authors found that both treatments were equally effective at reducing personality pathology. Only in neuroticism did the nonmanualized group do better during the follow-up period. The largest improvement was found in quality of object relations. For the remaining variables, only small and clinically insignificant magnitudes of change were found. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A model of domain-polymorph component for heterogeneous system design

Heterogeneous systems mix different technical domains such as signal processing, analog and digital electronics, software, telecommunication protocols, etc. Heterogeneous systems are composed of subsystems that are designed using different models of computation (MoC). These MoCs are the laws that govern the interactions of the components of a subsystem. The design of heterogeneous systems includes the design of each part of the system according to its specific MoC, and the connection of the parts in order to build the model representing the system. Indeed, this model allows the MoCs that govern different parts of system to coexist and interact.To be able to use a component which is specified according to a given MoC, under other, different MoCs, we can use either a hierarchical or a non-hierarchical approach, or we can build domain-specific components (DSC). However, these solutions present several disadvantages. This paper presents a new model of component, called domain-polymorph component (DPC). Such a component is atomic and is able to execute its core behavior, specified under a given MoC, under different host MoCs. This approach is not a competitor to the approaches above but is complementary.     

Effect of the treatment of wood shavings on the physico-mechanical characteristics of wood sand concretes

This study investigates the effect of a wood shaving treatment on the physico-mechanical characteristics of wood sand concretes. The two main objectives of this work are to improve a lightweight sand concrete and to valorise local materials and industrial wastes. Three wood shaving contents, two types of sand concretes (dune and river sand concrete) and a preliminary wood shaving treatment have been used. Sand, cement, filler, admixture and water composed the sand concrete matrix. The shaving treatment appreciably increases the mechanical strength of the studied composites without a large influence on thermal conductivity. The shrinkage of the composite is considerably reduced and the wood–matrix adherence is improved. At low wood contents, the dune sand concrete remains always slightly more insulating and less strong than the river sand concrete. At higher wood contents, the two concretes present almost similar properties.     

Building test cases and oracles to automate the testing of web database applications

Many organizations rely on web applications that use back-end databases to store important data. Testing such applications requires significant effort. Manual testing alone is often impractical, so testers also rely on automated testing techniques. However, current automated testing techniques may produce false positives (or false negatives) even in a perfectly working system because the outcome of a test case depends on the state of the database which changes over time as data is inserted and deleted. The Automatic Database Tester (AutoDBT) generates functional test cases that account for database updates. AutoDBT takes as input a model of the application and a set of testing criteria. The model consists of a state transition diagram that shows how users navigate pages, a data specification that captures how data flows, and an update specification that shows how the database is updated. AutoDBT generates guard queries to determine whether the database is in a state conducive to performing and evaluating tests. AutoDBT also generates partial oracles to help validate whether a back-end database is updated correctly during testing. This paper describes the design of AutoDBT, a prototype implementation, several experiments with the prototype, and four case studies.     

Hydroxyapatite deposition study through polymeric process on commercially pure Ti surfaces modified by laser beam irradiation

Many techniques have been used to coat metallic substrate with bioceramics. The aim of this study was to study the physical-chemical characteristics of polyvinylidene fluoride (α-PVDF)/hydroxyapatite (HA) composite coating, obtained by casting method, on commercially pure titanium (α-CP Ti) substrate surface modified by laser beam irradiation. The preparation of coating was done for mixing α-PVDF pellets shape dissolved in dimethylacetamide (DMA) with HA/DMA emulsion. The mixture was poured onto the α-CP Ti sample and left to dry in an oven. CP Ti plates were coated with α-PVDF/HA composite film, in proportions of 100/00 and 60/40 in weight, and characterized by particle size analysis, scanning electron microscopy, energy dispersive spectroscopy (EDS), X-ray diffractometry, thickness measurement and contact angle. Uniform coating with a small thickness variation along the coated surface was successfully obtained.     

Thermodynamic Measurements in a Strongly Interacting Fermi Gas

Strongly interacting Fermi gases provide a clean and controllable laboratory system for modeling strong interparticle interactions between fermions in nature, from high temperature superconductors to neutron matter and quark-gluon plasmas. Model-independent thermodynamic measurements, which do not require theoretical models for calibrations, are very important for exploring this important system experimentally, as they enable direct tests of predictions based on the best current non-perturbative many-body theories. At Duke University, we use all-optical methods to produce a strongly interacting Fermi gas of spin-1/2-up and spin-1/2-down ⁶Li atoms that is magnetically tuned near a collisional (Feshbach) resonance. We conduct a series of measurements on the thermodynamic properties of this unique quantum gas, including the energy E, entropy S, and sound velocity  c. Our model-independent measurements of E and S enable a precision study of the finite temperature thermodynamics. The E(S) data are directly compared to several recent predictions. The temperature in both the superfluid and normal fluid regime is obtained from the fundamental thermodynamic relation T=? E/? S by parameterizing the E(S) data using two different power laws that are joined with continuous E and T at a certain entropy S _c, where the fit is optimized. We observe a significant change in the scaling of E with S above and below S _c. Taking the fitted value of S _c as an estimate of the critical entropy for a superfluid-normal fluid phase transition in the strongly interacting Fermi gas, we estimate the critical parameters. Our E(S) data are also used to experimentally calibrate the endpoint temperatures obtained for adiabatic sweeps of the magnetic field between the ideal and strongly interacting regimes. This enables the first experimental calibration of the temperature scale used in experiments on fermionic pair condensation, where the ideal Fermi gas temperature is measured before sweeping the magnetic field to the strongly interacting regime. Our calibration shows that the ideal gas temperature measured for the onset of pair condensation corresponds closely to the critical temperature T _c estimated in the strongly interacting regime from the fits to our E(S) data. We also calibrate the empirical temperature employed in studies of the heat capacity and obtain nearly the same T _c. We determine the ground state energy by three different methods, using sound velocity measurements, by extrapolating E(S) to S=0 and by measuring the ratio of the cloud sizes in the strongly and weakly interacting regimes. The results are in very good agreement with recent predictions. Finally, using universal thermodynamic relations, we estimate the chemical potential and heat capacity of the trapped gas from the E(S) data.