5,320 research outputs found
Optical and aerodynamic focusing of isolated particles for diffractive imaging experiments at X-ray free electron lasers
No full textThe highly brilliant, short and coherent pulses produced by X-ray free-electron lasers (XFELs) opened up a unique opportunity to image small objects in nature, such as protein macromolecules, clusters, viruses and nanoparticles with nearly atomic spatial resolution, and their dynamic processes can be probed with femtosecond temporal resolution. Single-particle imaging (SPI) is a coherent diffraction imaging technique at XFELs that consists of directing a stream of randomly oriented isolated bio-particles across the focus of the X-ray beam to construct high-resolution 3D structure from diffraction patterns of multiple identical particles. Since the intense X-ray pulses destroy every particle upon interaction, a constant replenishment of sample is required. However, efficiently and successively placing of the biological single particle, which are typically few tens of nanometer in size, onto the few hundred nanometer X-ray beam still remains a considerable challenge.The main objective of this dissertation is to demonstrate an alternative aerosol focusing mechanism that efficiently and precisely delivers isolated particles into the focus of the XFEL beam, intended primary for SPI experiments. To this end, two complementary techniques were studied. The first method dealt with aerodynamic focusing of aerosol particles using an improved aerosol injector design, which is based on a simple convergent nozzle geometry. Through high-speed optical imaging, it was shown that 300 nm virus particles can be focused down to a 3.5 μm FWHM spot, which is considerably smaller than the existing aerosol injectors can achieve. The use of this injector for SPI experiment was demonstrated in a micro-focused soft-X-ray FEL beam at the FLASH facility in Hamburg, delivering virus particles, and a hit fraction > 18 % was recorded. Furthermore, delivering macromolecular nanocrystals of Cydia pomonella granulosis virus (CpGV), in serial femtosecond crystallography (SFX) experiments at the LCLS CXI hard X-ray instruments, extremely low background Bragg diffraction has obtained.The second part of the dissertation reports, for the first time, the confining and concentrating of aerodynamically delivered high-speed particle beam using a structured laser illumination. In this proof-of-concept experiment, an aerosol beam from a capillary aerosol injector was delivered into vacuum against a counter-propagating laser beam. The beam was constructed with Laguerre-Gaussian or a slowly diverging Quasi-Bessel beam that has a dark core in the middle. We call such beam an optical funnel. The optical force, governed by the spatial profile of the optical funnel, axially decelerate and lateral confine the particles to guide them into a convergent trajectories. Using this technique, a CpGV particle beam moving with an axial velocity of 17.4 ± 0.93 m/s, was transversely confined by a factor of two from its original width and its central peak particle density was increased by more than four times from the reference (laser-off) condition. Prospectively, optical guiding combined with the aerodynamic focusing may further advance single particle imaging experiments, by solving the principal problem of the precise and efficient delivery of isolated single particles to the sub-micron X-ray focus
Blended Learning System for Further and Higher Education Mechanical Engineering Courses in Bahrain
No full textTeaching and learning processes that are being followed globally by education providers consist of conventional face-to-face approach. Various socio-economic indicators have increased the pressure on Engineering Education in Bahrain in order to equip the students with both cognitive and psychomotor skills that are required by the labour market. The globalisation, along with the interdependence of various economies, has resulted in creating an extra dimension to the higher order of skills requirements. Hence, there is a need to develop new teaching and learning (T & L) methodologies that can comply with the ever increasing demands of the industry, regarding the skills of engineering students. In this study, the author has presented a comparison between various teaching and learning methodologies being implemented on the students of Higher National Diploma at Sheikh Khalifa Institute (SKI), Kingdom of Bahrain.
The author reviewed the effectiveness of the conventional teaching and learning methodology by comparing the pre-results with post-results. The same has been carried out on two novel T & L methodologies developed in these study i.e. computer-assisted instructions (CAI) and Blended Learning method, on imparting higher order of cognitive and psychomotor skills to engineering students. The study has been conducted on various groups of Higher National Diploma (HND) students at SKI. The study makes use of various questionnaires design especially for both the students and the teachers about their views on different T & L methodologies being implemented. It has been observed that computer-assisted instructions, when used with the conventional T & L methodology, perform superiorly than blended e-learning method or the conventional method alone. Hence, it has been recommended that this novel T & L method be used in the future to Higher National Diploma students at SKI.
Further to the development of a novel T & L methodology that performs better than the conventional T & L method, novel mathematical models have been developed for T & L methodology for both the cognitive and psychomotor domains. These mathematical models are based on the findings of the present study. These mathematical models explain the learning process of the students at microscopic level, in contrast to the conventional macroscopic evaluation method where only the marks obtained by the students indicate the quantitative learning. Furthermore, a novel Blended Learning package (containing tutorials for various Mechanical Engineering modules) has been developed based on the students-centred learning, considering institutional, pedagogical and technological contexts of service and product implementation. In this perspective, the novel Blended Learning package has been designed and developed in order to minimise/close the gaps between higher education at SKI and the requirements of the labour market
Interview with Salah Taher
No full textفي هذه المقابلة، يتحدث صلاح طاهر، رائد الفن التجريدي في مصر، عن لقائه بالأديب المصري عباس محمود العقاد. أجرى المقابلة حسن شمس الدين.In this interview, Salah Taher, a pioneer of abstract art in Egypt, recounts meeting Egyptian author Abbas Mahmoud al-Akkad. The interview was conducted by Hassan Shams al-Din
Uncertainties based queries for Interactive policy learning with evaluations and corrections
No full textGreen Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Learning & Autonomous Contro
Interview with Salah Montaser
No full textمقابلة مع كاتب وصحفي مصري شهير بجريدة الأهرام وصاحب عمود يومي بعنوان مجرد رأي، صلاح منتصر، يناقش فيها تقييمة وتوقعاتة السلبية لموقف حرب العراق للكويت، والحصار الإقتصادي الذي تفرضه الدول العربية علي العراق. قام بالمقابلة إبراهيم عابدين.An interview with a famous Egyptian writer and journalist in Al-Ahram newspaper and author of a daily column 'Just an Opinion"", Salah Montaser, in which he discusses the Iraq war on Kuwait, and the economic blockade imposed by Arab countries on Iraq. The interview was conducted by Ibrahim Abdeen
Where are the mothers? Interrogating maternal mortality as a violation of the rights to life and health : a Nigerian and Ethiopian perspective
No full textA Dissertation submitted to the Faculty of Law University of Pretoria, in partial fulfilment of the requirements for the degree Masters of Law (LLM in Human Rights and Democratisation in Africa). Prepared under the supervision of Dr. Salah Hammad, Faculty of Law, Addis Ababa University, AddisThesis (LLM (Human Rights and Democratisation in Africa))--University of Pretoria, 2009.The author argues that maternal mortality can easily be avoided and that the right to health and life is as much a developmental issue as it is one of human rights. Focuses on the maternal mortality ratio and relevant laws protecting women’s right to life and health in Nigeria and Ethiopia.http://www.chr.up.ac.za/Centre for Human RightsLL
An analytical study of the theatre of the Syrian playwright Saadallah Wannous, with particular emphasis on the plays written after the 1967 war
No full textThis study is an examination of the life and work of
the Syrian dramatist Saadallah Wannous (1941-1997). Wannous's name is virtually unknown in the West; only two academic studies of any significance have appeared in English on this eminent and challenging writer, who was honoured by UNESCO at the end of his life. Even in the Arab world his standing rests largely upon his celebrity as a cultural icon, since professional performances of his plays are rare due to the decline of the theatre in the region, and little attention has been devoted to theatre studies by Arab academics. The two studies in English do not attempt to be comprehensive but focus on particular stages of Wannous's career. This study is, therefore, the first to encompass the full range of Wannous's work. To do so it combines an account of his life which seeks to comprehend the various forces that shaped his thinking with an analysis of his dramatic works. The study concentrates on the plays written in the years following the trauma inflicted on the Arab world by the catastrophe of their
defeat in the Arab-Israeli war of June, 1967. Wannous's career can be divided into three phases: the immature plays of his young manhood which are influenced by European models and generally focus on the social condition of the individual; his middle period - the `theatre of politicisation', when his Marxist politics were the main
factor shaping his drama; and his late works, which are characterised by an extraordinary freedom of thought and expression. The introduction places Wannous in his historical and sociocultural context and provides a brief background explaining the literary and theatrical traditions of the Arab world that influenced his activity as a dramatist. Each phase is then examined in turn and the plays are analysed in accordance with the focus of the study. This means that emphasis is given to the middle period,
but no significant work is neglected. The study aims to trace the trajectory of Wannous's development using a
variety of sources: the plays themselves, Wannous's own journalism and critical writings, interviews with his widow, his friends and colleagues, and numerous
journals, books and articles, some of which contain
important interviews with Wannous that shed light on his thought and ways of working. Use is also made of the
two studies mentioned above. The study shows that Wannous's theatre was influenced by the key political, social and cultural developments of his time, and that he
constantly sought to find forms that would express those transformations in dramatic terms
Operations of semiconductor lasers under optical feedback with linewidth enhancement factor
No full textSyntaxonomie des groupements préforestiers et steppiques de l’Algérie aride
No full textThe author presents a synthesis of the syntaxonomy of pre foresty and steppic groupings in arid Algeria. Characterized by a floristic diversity and a high variability of environmental conditions, the area strenches upon twenty millions hectares.
The author, concerning the vegetation enphasizes upon the distinct paralelism between, on the one hand, the ditribution of the physionomical types and on the other hand, the global aridity of climate, the geomorphological types and the soil conditions. The various studies of syntaxonomy within the ten past years did not come to a satisfactory diagnosis. That seems due to the specific structuration of groupings imbricated in a real mosaic integrating the two communities of perrenial and annual plants. This structuration being taken into account allows KAABECHE (1990) to propose, temporary, a more satisfactory diagnosis for each of the two groupings separating the annual and the perenial components.L’auteur présente une synthèse des travaux sur la syntaxonomie des groupements préforestiers et steppiques de l'Algérie aride. Caractérisée par une diversité floristique et une grande variabilité des conditions de milieu, la région d’étude s’étend sur près de vingt (20) millions d'hectares.
S’agissant du déterminisme de végétation, l’auteur met en relief le net parallélisme entre la distribution des types physionomiques d’une part, l’aridité globale du climat, les types géomorphologiques et les conditions édaphiques d’autre part.
En syntaxonomie les nombreux travaux de ces deux dernières décennies n’ont pas pu aboutir à une diagnose satisfaisante. Cela semble dû essentiellement à la structuration spécifique des groupements, intriqués en véritable mosaïque intégrant les deux communautés «vivaces» et annuelles. La prise en compte de cette structuration a permis à KAABECHE (1990) de proposer provisoirement une diagnose plus satisfaisante pour chacune des deux phytocenoses «vivaces» et «annuelles».Djebaili Salah. Syntaxonomie des groupements préforestiers et steppiques de l’Algérie aride. In: Ecologia mediterranea, tome 16,1990. pp. 231-244
A Computational Analysis of Tentativeness and Causation in Design Talk
No full textAbstract. Analysing records of design activity such as transcripts or documents have typically involved close reading of transcripts and manual identification of concepts and behaviours. We explore the applicability of a machine-learning based computational tool—called Empath—in identifying high-level patterns in design talk. Specifically, we use it to examine the datasets from the Design Thinking Research Symposium (DTRS) workshops for two contrasting aspects of design talk—the expression of tentativeness that characterises designers’ exploration of the problem-solution space, and the expression of causal reasoning that characterises designers’ analytical thinking. We find that such a tool can be effectively used as a means of “distant reading”. However, the lack of design relevance in the tool’s training data results in ambiguities and mis-categorisations that still need resolution through close reading.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Methodologie en Organisatie van Desig
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