Search results for "first"

Über den einfluß des lösungsmittels beim thermischen zerfall des azoisobuttersäuredinitrils

1967

Der Zerfall des Azoisobuttersauredinitrils wurde in 10 verschiedenen Losungsmitteln kinetisch untersucht. Er ist streng eine Reaktion erster Ordnung. Die Zerfallsgeschwindigkeit ist in den einzelnen Losungsmitteln verschieden. Der maximale Unterschied betragt bei 60°C 40% (Malonsaurediathylester/Cyclohexanol), entsprechend einer Differenz der Freien Enthalpie des Ubergangszustandes von 250 cal/Mol. Die starkeren Anderungen der Aktivierungsenthalpie bis zu 1,5 kcal/Mol werden durch entsprechende Anderungen der Entropie des Ubergangszustandes kompensiert. The thermal decomposition of azo-bis-isobutyronitrile in a series of 10 solvents was investigated. The reaction is strictly of first order.…

1976

The thermal degradation of poly(oxycarbonylpentamethylene), (poly-e-caprolactone), (3), was investigated at 220°C and 80 mm Hg under nitrogen. 3 was found to be thermally much more stable than poly(oxycarbonylethylene), (poly-β-propiolactone), (1), although it decomposed faster than poly(oxycarbonyl-1,1-dimethylethylene), (polypivalolactone), (2). The reaction was of the first order with a rate constant of k=6,2.10−4 min−1 and proceeded via a “zipper mechanism” to yield monomeric e-caprolactone. Der thermische Abbau von Poly(oxycarbonylpentamethylen), (Poly-e-caprolacton), (3), wurde bei 220°C im Stickstoffstrom bei 80 mm Hg untersucht. Dabei wurde gefunden, das 3 thermisch wesentlich stabi…

Covalently linked multi-calixarenes

1998

Abstract ipso-Nitration of t-butyl calix[4]arene tetraethers and subsequent hydrogenation provides an easy access to monoamino calix[4]arenes. Reaction with di- and triacid chlorides leads to various double- and triple-calix[4]arenes. With tetraacid chlorides derived from calix[4]arenes in the cone- or 1,3-alternate-conformations penta-calix[4]arenes are available as molecularly uniform species, which may be regarded as the first generation of calix[4]arene based dendrimers. The structure of the mononitro tetraester derivative, which may serve as a general building block has been confirmed by single crystal X-ray analysis.

EXPLORING SPECIFIC EFFECTS OF TYPE AND TIMING OF EXPOSURE TO CHILDHOOD ADVERSITY AND SYMPTOM DOMAINS IN FIRST EPISODE OF PSYCHOSIS: PRELIMINARY RESUL…

2019

Prevenire l’insuccesso scolastico nella scuola secondaria di primo grado: scuola e territorio dialogano

2017

Con il lavoro di co-progettazione per la promozione di una rete integrata tra soggetti pubblici e privati attraverso lo sviluppo di una metodologia di sistema, l’ideazione e realizzazione di strumenti di supporto, è stato offerto un contributo per il contrasto del fenomeno della dispersione scolastica e per la prevenzione del rischio di marginalità sociale negli adolescenti di Palermo. Il progetto ha coinvolto 172 studenti, 171 genitori e 29 docenti di tre scuole secondarie di primo grado, 10 operatori del terzo settore del territorio del Comune di Palermo. Si è partiti dal presupposto che per favorire la dimensione orientativa della scuola media fosse necessario incentivare il dialogo tra …

Cuando la historia está presente: Argumentos a favor de la sociología histórica

2019

Sociology and history have maintained a discontinuous relationship and a permanent discussion. Classical sociology is intrinsically historical, but after the first theoretical synthesis the dialogue between both disciplines was extinguished and it has often been necessary to defend the need for the historical view in sociology from the margins of the dominant paradigm. However, as a specialty or subdiscipline, historical sociology has consolidated its own academic space and a strong theoretical, methodological and conceptual body. In Spain this process of institutionalization has not yet success. In this article we expose a few arguments in defense of historical sociology, both theoretical …

Postbuckling analysis of cracked stiffned plates by pb–2 Rayleigh-Ritz method

2015

A Rayleigh-Ritz approach for the analysis of buckling and post-buckling behavior of cracked composite stiffened plates is presented. The structure is thought as the assembly of plate elements modeled by the first order shear deformation theory. Continuity along the edges common to contiguous elements are enforced by using penalty techniques, which also allow to straightforwardly implement efficient crack modeling strategies. General symmetric and unsymmetric stacking sequences are considered and numerical procedures have been developed and used to validate the present solution by comparison with FEA results. Original results are also presented for post-buckling solution of multilayered stif…

Effect of Pulp Pigmentation Intensity on Consumer Acceptance of New Blood Mandarins: A Cross-Cultural Study in Spain and Italy

2022

One of the current objectives of different citrus breeding programmes is obtaining new pigmented mandarins. This study investigates to what extent consumer preferences, expectations and purchase intention are affected by the appearance of new mandarins, specifically pulp pigmentation intensity. Four hundred consumers from both Italy and Spain (800 in all) participated in the study. In each country, half were informed about the healthy properties of the anthocyanins responsible for red pulp colouration, while the other half were not. Italians more readily accepted new mandarin varieties than Spaniards, which was linked to them being more familiar with blood oranges. In Italy, both slight- an…

Establishing a Standardised Procedure for Building Learner Corpora

2014

Decisions at the outset of preparing a learner corpus are of crucial importance for how the corpus can be built and how it can be analysed later on. This paper presents a generic workflow to build learner corpora while taking into account the needs of the users. The workflow results from an extensive collaboration between linguists that annotate and use the corpus and computer linguists that are responsible for providing technical support. The paper addresses the linguists’ research needs as well as the availability and usability of language technology tools necessary to meet them. We demonstrate and illustrate the relevance of the workflow using results and examples from our L1 learner cor…

Trabajo y TIC en los mayores de 45 años. Un análisis de la introducción al ciberespacio desde la esfera laboral

2018

The inequality in access to cyberspace due to age at the beginning of the twenty-first century was followed by an economic crisis that intensified many socio-labor dynamics. Through a contextualization with INE data and a qualitative sample, the following work tries to capture the attitudes about ICT related to their previous labor trajectories on those over 45 years of age; and, on the other hand, its introduction to cyberspace from work as a conditioner in the perception of crisis, the maintenance of employment or their way out to retirement.