814 research outputs found

    SRAT-Distribution Voltage Sags and Reliability Assessment Tool

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    Interruptions to supply and sags of distribution system voltage are the main aspects causing customer complaints. There is a need for analysis of supply reliability and voltage sag to relate system performance with network structure and equipment design parameters. This analysis can also give prediction of voltage dips, as well as relating traditional reliability and momentary outage measures to the properties of protection systems and to network impedances. Existing reliability analysis software often requires substantial training, lacks automated facilities, and suffers from data availability. Thus it requires time-consuming manual intervention for the study of large networks. A user-friendly sag and reliability assessment tool (SRAT) has been developed based on existing impedance data, protection characteristics, and a model of failure probability. The new features included in SRAT are a) efficient reliability and sag assessments for a radial network with limited loops, b) reliability evaluation associated with realistic protection and restoration schemes, c) inclusion of momentary outages in the same model as permanent outage evaluation, d) evaluation of the sag transfer through meshed subtransmission network, and e) simplified probability distribution model determined from available faults records. Examples of the application of the tools to an Australian distribution network are used to illustrate the application of this model

    Sanitation and Hygiene of Darjeeling City: A Crisis for Women and Adolescent Girls

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    By the end of the Millennium Development Goal's target year, 2015, India had been declared as a country, which has made moderate progress in terms of improvement in basic sanitation provision for all. Yet open defecation is still a regular practice of a significant proportion of the population in both urban and rural areas. The Indian government has been trying to address this problem for the last three decades through different programmes. However, though the effort is laudable, in reality, the countrywide situation is not so praiseworthy. Lack of sanitation provisions affects people in different ways with different intensities along the lines of class, gender, age, disability, and marginality. In Darjeeling city, due to lack of proper sanitation facilities, a significant portion of the population uses public toilets, which are less in number compared to the demand. People face a variety of difficulties and hurdles in using public toilets, and as a result, continue to practice open defecation during the night and early morning. Among the users, women and adolescent girls suffer more than the others. Moreover, in this city, a significant portion of the population faces acute water crisis during the dry months. This empirical study tries to explore the different ways through which women and adolescent girls are affected by the lack of safe sanitation facilities within the house premises. The article also argues that lack of sanitation provision should be considered as a matter of violence against women and adolescent girls because the situation makes them vulnerable to the risk of being violated or sexually abused

    Formulation strategies and engineering processes for orally disintegrating tablets:the importance of robustness and disintegration

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    Orally disintegrating tablets (ODTs) are a dosage form ideal for paediatric or geriatric patients as they disintegrate/disperse within the oral cavity. Direct compression manufacture of ODTs is increasing in popularity due to its cost effectiveness and use of traditional tableting equipment, however excipients are required to fulfil certain requirements to form robust, fast disintegrating tablets. Mannitol is a vital excipient for ODT manufacture due to its high palatability, however its fragmentation behaviour under compression leads to mechanically weak and friable tablets. The work in this thesis aimed to investigate the fragmentation behaviour of milled mannitol, followed by development of preblends to obtain ideal ODT properties without the use of any superdisintegrant. Development of a novel method for ODT disintegration testing was also conducted due to the lack of current techniques that are representative of oral conditions.Mannitol fracture occurred primarily at the (011) crystal plane, which was the most hydrophilic, therefore increasing the wettability of milled mannitol. Resulting ODTs had a faster disintegration time than the unmilled equivalent, with enhancement in compressibility due to increased plastic deformation. Milled mannitol presented a suitable alternative for ODT production compared to current commercial grades, with high mechanical strength and improved disintegration time. Novel optimised ODT preblends were developed with milled mannitol incorporated alongside micro crystalline cellulose (MCC) and silica to aid powder flow.Dry particle coating was also employed to develop an MCC/silica hybrid to enhance MCC properties. Silicified MCC had previously been shown to enhance MCC compression, whilst improving MCC powder flow and reducing lubricant sensitivity. Dry coated MCC was optimised with 1%w/w silica, with ODT disintegration being significantly lower than the spray dried alternative or uncoated MCC, whilst allowing a 40% drug load of a non-compressible API to be formed into a robust fast disintegrating ODT.A novel ODT disintegration method was developed to mimic In Vivo oral conditions. A vastly improved correlation to In Vivo results was observed with the newly developed method, in comparison to the recommended USP tester, with a linear correlation obtained with the new test method compared to the curved dataset gathered with the USP test.Novel preblends were developed utilising dry particle coating, with resultant ODTs showing improved ODT behaviour, with disintegration time being low even without the use of superdisintegrant. To supplement ODT disintegration, novel ODT disintegration time test method was developed and results indicated it was a superior alternative compared to the currently recommend USP test

    On the imidazole-2-thione-based route to tricyclic 1,4-diphosphinines: synthesis, structures and reactions

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    The PhD Thesis “On the imidazole-2-thione-based route to tricyclic 1,4-diphosphinines: synthesis, structures and reactions” describes the synthetic concept to and first studies on the chemistry of novel tricyclic 1,4-dihydro-1,4-diphosphinines and 1,4-diphosphinines. In the first part, synthesis of the major starting material, the (Et2N)2P- and Et2N(Cl)P-substituted imidazole-2-thiones is described. The latter was converted into tricyclic 1,4-dihydro-1,4-diphosphinines via an LDA-induced double salt metathesis. Further studies on Et2N(Cl)P-substituted imidazole-2-thiones focused on backbone phosphaalkenyl substituted imidazole-2-thiones and/or imidazole-2-ylidenes. The chemistry of tricyclic 1,4-dihydro-1,4-diphosphinines were explored in various directions ranging from P-oxidation to P-functionalization and competing P/S-centered reactions with electrophiles; the latter was accompanied by theoretical studies (A. Frontera). Furthermore, reduction of 1,4-dichloro-1,4-dihydro-1,4-diphosphinines with a mild reducing agent enabled access to first examples of isolated stable, red 1,4-diphos-phinines which are very sensible towards moist air. The 1,4-diphosphinines were fully characterized including cyclic voltammetry (CV) and UV/vis measurements as well as theoretical bonding analysis (L. Nyulaszi). Among the remarkable results are a reversible 3e-reduction (CV) and that the LUMO is largely concentrated on the phosphorus centers. The latter explains why anionic nucleophiles add to the phosphorus centers in a 1,4-fashion to produce anionic phosphanido centers which can be quenched with electrophiles. Further investigations revealed that 1,4-diphosphinines are excellent dienophiles in [4+2] reactions including a wide variety of C-C and N-N p-systems, but also s-bonds as in diphenyl dichalcogenides (E = S, Se). The latter reactions led exclusively to trans products which was explained on the basis of DFT calculations as a sequence of 1,4-addition followed by P-inversion (L. Nyulaszi)

    Power and sample size calculation of two-sample projection-based testing for sparsely observed functional data

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    Projection-based testing for mean trajectory differences in two groups of irregularly and sparsely observed functional data has garnered significant attention in the literature because it accommodates a wide spectrum of group differences and (non-stationary) covariance structures. This article presents the derivation of the theoretical power function and the introduction of a comprehensive power and sample size (PASS) calculation toolkit tailored to the projection-based testing method developed by Wang (2021). Our approach accommodates a wide spectrum of group difference scenarios and a broad class of covariance structures governing the underlying processes. Through extensive numerical simulation, we demonstrate the robustness of this testing method by showcasing that its statistical power remains nearly unaffected even when a certain percentage of observations are missing, rendering it 'missing-immune'. Furthermore, we illustrate the practical utility of this test through analysis of two randomized controlled trials of Parkinson's disease. To facilitate implementation, we provide a user-friendly R package fPASS, complete with a detailed vignette to guide users through its practical application. We anticipate that this article will significantly enhance the usability of this potent statistical tool across a range of biostatistical applications, with a particular focus on its relevance in the design of clinical trials

    The Covid-19 Lockdown and Its Impact on the Agri-Food Supply Chain in India: Insights from Government Policy Perspective

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    The outbreak of the Covid-19 pandemic is an unprecedented shock to the Indian economy. Agriculture being the backbone of the Indian economy has been severely affected by the shock waves of the Covid-19 pandemic and subsequent lockdown. In this paper, we have assessed the potential impact of the shock on Indian agriculture considering their implications along the different stages of supply chain, namely, production, post-harvest handling & storage, processing & packaging, distribution and consumption. In addition, we have analyzed the policies announced by the government in mitigating the impact of the shock and revitalizing the Indian agriculture. Finally, we have put forward some policy recommendations for future consideration
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