PEC Method Research Articles

Sarah Newman: Small Steps Forward: Using Games and Activities to Help Your Pre-School Child with Special Needs (Second Edition)

This is a book for parents written by a parent. There are plenty of practical advice and strategies to cope the many daily problems linked to having a child with special needs; in fact it is not conceived just for young children with autism, even if written by the mother of a child with autism. The absence of up-to-date references along the book, and also in the References section, can create in the specialist some perplexity, but little by little the reading appears easy and complete for helping a parent and for suggesting him to have the book on the shelf as a consultant at home. As a second step, professionals realize that it is full of wise, tactful and sensible suggestions that can be useful also for him when confronted with the many questions usually arose by parents during consultations. The book is organized in eleven chapters that can be summarized as follows. The first two chapters are introductory to how parents can organize their life when a child with special needs has arrived in the family; how to survive to the unexpected event and to the diagnosis; how to reorganize the environment at home to make it in tune with the child. The following seven chapters analyze separately the different areas of development: cognitive, linguistic, gross and fine motor, sensory, social, emotional, and finally behavior, sleep and toileting. Each of these chapters is composed of two interconnected parts: theory (what that development is, chronological development, parallel development) and games and activities (general guidelines, chronological development, parallel development). The aim of the final two chapters is to help parents in disentangling from the jungle of professionals and services, giving them elementary information on how to deal with them at the different ages of the preschool period of life, and also how to find sources of support, where to buy special toys and the name of organizations devoted to specific disorders. Among chapters dedicated to development this new edition has changed a lot in dealing sensory development. Now this chapter incorporates the two sisters concept of sensory integration and sensory integration dysfunction. By this way it takes in consideration the work of Winnie Dunn on the sensory profile and of Stanley Greenspan on the individual differences, even if these authors are not quoted. Again, professionals can remain unsatisfied for the lack of precision in quoting literature and scientific bases of statements, but unlikely he will find erroneous advice that, furthermore, are always written in a positive way and with the permanent ability to create hope into the child’s development. This is a book that balances other books derived from behavioral approaches. It is not written to tell the parents what they should do with their child. It is much more development based and its leitmotivs seem to be: stay in tune, do not focus on a skill, enlarge the experience, pay attention not only to chronological development in one area but also to parallel development of other areas, follow your child. Rather than directive interaction styles, it emphasized the importance of play for learning, the social contexts of learning, and the interdependence of physical, cognitive and emotional activity. Nevertheless it does not forget to quote the ABCC method for behavioral problems or the PECS method for communication disorders. Especially, it does not forget to remind parents that they need to create team work with professionals and that their competence has an end where the specialist’s competence begins. So, why to recommend this book? Our ability to identify infants, toddlers and young children with suspected or F. Muratori (&) University of Pisa, IRCCS Stella Maris, Via dei Giacinti, 2, 56122 Calambrone (Pisa), Italy e-mail: f.muratori@inpe.unipi.it; filippo.muratori@inpe.unipi.it

Etching, Raman and PL study of thick HVPE-grown GaN

HVPE-grown homo-epitaxial 2 mm thick GaN single crystals were examined using different techniques, including orthodox defect-selective etching in molten bases and electroless photo-etching (PEC method) in aqueous KOH solution, micro-Raman spectroscopy and photoluminescence (PL). Examination was performed on the (1 0 −1 0) longitudinal cross-section, which was parallel to the macroscopic [0 0 0 1] growth direction of the crystal. Surface features formed during etching were examined using DIC optical microscopy, scanning electron microscopy (SEM) and atomic force microscopy (AFM). Different types of crystallographic and electrically active defects were recognized and analyzed. These are: individual and aligned dislocations, large areas of remarkably different carrier concentration and local growth striation patterns. Both etching methods revealed the presence of individual dislocations and low-angle grain boundaries with dislocation lines parallel and perpendicular to the [0 0 0 1] growth directions. Photo-etching showed remarkable difference of etching rate and defect type/density in the central part of the GaN crystals and in so-called wings. Very low rate of PEC etching of wings resulted from remarkably increased carrier concentration in this part of the crystal, as was established by micro-Raman spectroscopy. In the wings other peculiar structural features were revealed, namely areas with clear, but randomly oriented growth striation patterns. Micro-Raman measurements showed large local differences in carrier concentration inside and outside these areas. PL examination remained in good agreement with the results of etching and Raman spectroscopy: the spectra taken from the central part of the crystal were typical for low carrier concentration GaN (clear DBA pick at 3.47 eV), while spectra from the wings were very broad, typical for high carrier concentration material.

Fabrication of Silicon Nitride Ceramics with Electrical Conductivity

The electrical conductivity was provided to structural ceramics by controlling the grain boundary phase. We focused on the grain boundary phase of Si3N4 ceramics, which can be considered as an infinite network for conducting paths. In this study, we investigated the correlationship of the microstructure, mechanical properties, and electrical conductivity of Si3N4 ceramics with V2O5 based glasses. The Si3N4 ceramic with V2O5 based glasses were successfully fabricated by controlling the composition of grain boundary phase. Fabricated materials by a PECS method indicated a very fine microstructure. The mechanical properties of Si3N4 ceramics with V2O5 based glasses were not good compared to those of conventional Si3N4. However, the values for the SNVB and the SNVBA were four or six orders of magnitude higher at room temperature and had excellent mechanical properties compared to pure V2O5 based glasses.

Defect‐selective etching of SiC

AbstractTwo methods of defect‐selective etching of SiC are described: (i) orthodox etching in molten KOH–NaOH eutectic with 10% of MgO powder (E + M etch) and (ii) electroless photo‐etching in aqueous KOH solutions (PEC method). The first etch shows similar effectiveness in revealing different type of dislocations, micropipes and stacking faults, as the commonly used molten KOH. The second approach is new for studying defects in SiC and is most suitable for revealing stacking faults both on the disoriented (0001) basal planes and on the ($1 \bar1 00$) cleavage surfaces. Cross‐calibration of both techniques and examples of calibration of PEC etch features by TEM are shown. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Preparation and Evaluation of Dense Hydroxyapatite by PECS Method

Preparation and Evaluation of Dense Hydroxyapatite by PECS Method

Characterization of GaN single crystals by defect‐selective etching

In this communication it is shown that both “orthodox” etching in molten KOH–NaOH eutectic (E etch and its modification) and photo-etching in aqueous KOH solution (PEC method) permit quick assessment of density, distribution and, after appropriate calibration, type of defects in GaN single crystals and epitaxial layers. Characteristic features of both etching methods are briefly discussed. It is shown that dislocations and micro-defects can be revealed in the form of etch pits (in “orthodox” E etch) and as etch hillocks (PEC method) on both Ga- and N-polar surfaces. The reliability of both methods has been confirmed by direct TEM calibration and by using indentation method. Very low dislocation density (EPD ≤ 2 × 102 cm–2) in the undoped GaN single crystals and MOCVD-grown epitaxial layers has been confirmed by this study.

Investigation of Cornmeal Components Using Dynamic Vapor Sorption and Differential Scanning Calorimetry

ABSTRACTDegermed cornmeal, native starch, and corn gluten meal were individually extruded. DVS technology was used to produce isotherms and to condition extrudates to a constant moisture for Tg analysis. The DVS method results are compared to a PEC method. DSC was used to determine Tg. Isotherm and Tg data for starch and corn gluten meal were used to predict cornmeal snack sorption and Tg behavior.The Tg for extruded cornmeal, dent starch, and corn gluten meal at 18.5%db moisture content were 46.2, 49.4, and 12.7 °C, respectively. This suggests that the polymeric fractions of cornmeal (starch, protein) contribute to the Tg of cornmeal approximately based on the weight fraction of each polymer.

Introduction of coupled thermomechanical equations into a hydrocode

A computational procedure to solve the coupled thermomechanical equations is developed by means of a three-dimensional explicit Lagrangian hydrocode. The basic field equations including thermal effects are first presented. Then, after a brief overview of the original PEC method [1] to solve the coupled equations in an explicit manner, it is extended to a general purpose hydrocode. The numerical procedures are listed in a step-by-step sequence. Finally, a sample computation is conducted for a cylinder impact test and compared with the corresponding experimental result.

Efficacy of Petrifilm™ E. coli Count Plates for E. coli and Coliform Enumeration

The Petrifilm E. coli Count plate (PEC) method was compared to the AOAC MPN method to determine the efficacy of the PEC method to detect E. coli and coliforms in 115 inoculated cheese samples, 94 vegetables samples, and in 100 naturally contaminated poultry samples. The PEC method was compared to two other coliform plate count methods. The 24 h PEC method is as good as or better than the AOAC MPN method for the detection of E. coli. In addition, qualitative results suggest that the PEC method may be more sensitive than the 9 tube MPN method for the detection of very low numbers of E. coli. Comparable coliform results were obtained.

Electroless Deposition of CdTe Thin Films

not Available.