81 research outputs found
School Meals Case Study: Armenia
Full text linkThis school meals case study forms part of a collection led by the Research Consortium for School Health and Nutrition’s "Good Examples" Community of Practice. The School Meals Case Study of Armenia serves to document how the national school meals programme is organized, funded, and monitored throughout the country. The objectives of this case study include presenting an introduction to the country profile, outlining the design and implementation of school feeding programmes, describing their monitoring and evaluation processes, and highlighting lessons learned, best practices, and challenges. This case study is written as a working paper, and can be updated to reflect evolving circumstances. The ‘Good Examples’ Community of Practice supports the evidence generation of the Research Consortium for School Health and Nutrition, the evidence-generating arm of the School Meals Coalition. The Research Consortium’s objective is to carry out independent research across diverse sectors and generate solid, compelling, and actionable evidence regarding the benefits of school food programs to inform evidence-based decision-making on school health and nutrition policies and practices
LTE Advanced: Technology and Performance Analysis
Full text linkWireless data usage is increasing at a phenomenal rate and driving the need for continued innovations in wireless data technologies to provide more capacity and higher quality of service. In October 2009, 3rd Generation Partnership Project (3GPP) submitted LTE-Advanced to the ITU as a proposed candidate IMT-Advanced technology for which specifications could become available in 2011 through Release-10 . The aim of “LTE-Advanced” is to further enhance LTE radio access in terms of system performance and capabilities compared to current cellular systems, including the first release of LTE, with a specific goal to ensure that LTE fulfills and even surpass the requirements of “IMT-Advanced” as defined by the International Telecommunication Union (ITU-R) .
This thesis offers an introduction to the mobile communication standard known as LTE Advanced, depicting the evolution of the standard from its roots and discussing several important technologies that help it evolve to accomplishing the IMT-Advanced requirements. A short history of the LTE standard is offered, along with a discussion of its standards and performance. LTE-Advanced details include analysis on the physical layer by investigating the performance of SC-FDMA and OFDMA of LTE physical layer. The investigation is done by considering different modulation schemes (QPSK, 16QAM and 64QAM) on the basis of PAPR, BER, power spectral density (PSD) and error probability by simulating the model of SC-FDMA & OFDMA. To evaluate the performance in presence of noise, an Additive White Gaussian Noise (AWGN) channel was introduced.
A set of conclusions is derived from our results describing the effect of higher order modulation schemes on BER and error probability for both OFDMA and SC-FDMA. The power spectral densities of both the multiple access techniques (OFDMA and SC-FDMA) are calculated and result shows that the OFDMA has higher power spectral density.fi=Opinnäytetyö kokotekstinä PDF-muodossa.|en=Thesis fulltext in PDF format.|sv=Lärdomsprov tillgängligt som fulltext i PDF-format
Exploration of new sustainable synthetic methods for the synthesis of fused pyridines and 4-quinolones based on the domino reaction of chromones and other masked dielectrophiles with nucleophiles
Full text linkThe present work aimed to study the big potential of chromone derivatives and 1-(2-fluorophenyl)prop-2-yn-1-ones for the synthesis of purine-like fused pyridines and 4-quinolone derivatives. In this regard, a wide range of substituents and substitution patterns are tolerated in the reaction. In addition a new and easy way for synthesis of 4-quinolone derivatives and other fused systems via domino cycloaddition reactions of ortho-fluoro substituted benzoylchromones, 1-(2-fluorophenyl)prop-2-yn-1-ones and aliphatic or aromatic amines were developed
Cu-Catalyzed Arylation of Bromo-Difluoro-Acetamides by Aryl Boronic Acids, Aryl Trialkoxysilanes and Dimethyl-Aryl-Sulfonium Salts : New Entries to Aromatic Amides
Full text linkWe describe a mechanism-guided discovery of a synthetic methodology that enables the preparation of aromatic amides from 2-bromo-2,2-difluoroacetamides utilizing a copper-catalyzed direct arylation. Readily available and structurally simple aryl precursors such as aryl boronic acids, aryl trialkoxysilanes and dimethyl-aryl-sulfonium salts were used as the source for the aryl substituents. The scope of the reactions was tested, and the reactions were insensitive to the electronic nature of the aryl groups, as both electron-rich and electron-deficient aryls were successfully introduced. A wide range of 2-bromo-2,2-difluoroacetamides as either aliphatic or aromatic secondary or tertiary amides were also reactive under the developed conditions. The described synthetic protocols displayed excellent efficiency and were successfully utilized for the expeditious preparation of diverse aromatic amides in good-to-excellent yields. The reactions were scaled up to gram quantities
ChemInform Abstract: Efficient [5 + 1] Synthesis of 4‐Quinolones by Domino Amination and Conjugate Addition Reactions of 1‐(2‐Fluorophenyl)prop‐2‐yn‐1‐ones with Amines.
No full textNanocellulose as Convenient Reaction Media for the FeCl<sub>3</sub> Mediated Mechanochemical Synthesis of 3‑Acylchromones
No full textA solvent free strategy
for the mechanochemical synthesis of 3-acylchromones
has been developed via FeCl3-nanocellulose mediated dehydrative
coupling of ortho-hydroxyarylenaminones and carboxylic
acids. The ortho-hydroxyarylenaminones undergo electrophilic
domino cyclization followed by an unusual acylation event with carboxylic
acids in the presence of FeCl3 as the catalyst and nanocellulose
as the reaction media. The protocol was found to be simple, efficient,
and environmentally benign to obtain a diverse array of 3-acylchromones
with high yields. The protocol features advantages such as the use
of cheap and readily available carboxylic acids as acyl source and
no requirement of directing groups, oxidants, and solvents. Furthermore,
the utilization of a wood-derived material, nanocellulose as the biodegradable
reaction media and nontoxic iron salt as the catalyst under very mild
and solvent-free conditions makes this acylation protocol very interesting
in the perspective of the Green Chemistry principles
Application of Silicon-Initiated Water Splitting for the Reduction of Organic Substrates
Full text linkThe use of water as a donor for hydrogen suitable for the reduction of several important classes of organic compounds is described. It is found that the reductive water splitting can be promoted by several metalloids among which silicon shows the best efficiency. The developed methodologies were applied for the reduction of nitro compounds, N‐oxides, sulfoxides, alkenes, alkynes, hydrodehalogenation as well as for the gram‐scale synthesis of several substrates of industrial importance
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