1,720,977 research outputs found
Dependence of Anomalous Phosphorus Diffusion in Silicon on Depth Position of Defects Created by Ion Implantation
No full textTransient enhanced diffusion of phosphorus in silicon has been investigated for implants below and above the threshold for a complete amorphization. Rapid thermal processes (electron beam) and conventional furnaces have been used for the annealing. In the case of implants below amorphization, a strong enhanced diffusion, proportional to the amount of damage produced, has been observed. The extent of the phenomenon is practically independent of the damage depth position. In contrast to this, the formation of extended defects at the original amorphous-crystalline interface makes the diffusivity strongly dependent on depth in the case of post-amorphized samples. No enhanced diffusion effect is observed if the dopant is confined in the amorphous layer, while a remarkable increase in the diffusivity is detected for the dopant located in the crystalline region beyond the amorphous-crystalline interface
Process understanding of drying applied to wet granulation in single-pot equipment
No full textThe drying phase in single pot wet granulator-vacuum dryers has not been greatly investigated, however, this step is very important from an industrial manufacturing point of view expecially in terms of energy and time. According to the latest FDA guidance about Process Analytical Technologies (PAT), the most appropriate approach for optimizing pharmaceutical production involves process understanding.
The aim of this study was the process understanding of drying in a single pot granulator (Rotocube 60, IMA). In particular, the effect of three drying parameters (bowl temperature, vacuum and microwaves) on the granule characteristics (loss on drying, morphology, particle size, flowability and friability) of a placebo product (monohydrate lactose, corn starch and polyvinylpirrolydone as binder) was evaluated. The properties of the related tablets (uniformity of mass, crushing strength, friability, disintegration time) were also studied. The preliminary data obtained, using the above mentioned equipment and formulation, suggest that different drying conditions, which determine different drying times, do not significantly affect the technological characteristics of both granules and tablets. In conclusion, this result demonstrates a clear formulation robustness, giving the opportunity to find the shortest drying time pertinent to drying conditions once the process is scaled up to an industrial single pot granulator
Dependence of Transient Enhanced Diffusion on Defects Depth Position in Ion Implanted Silicon
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Drug layering in a perforated pan: impact of up-scaling on coating distribution uniformity
No full textThe growing interest in incorporating an active ingredient in the coating formulation requires that both process and equipment ensure uniform distribution of the coating material. Up to date the majority of the papers refers to optimisation of drug layering on cores in pan applied to small or pilot scales. However it is crucial for the pharmaceutical industry to be sure that the coating uniformity is maintained and guaranteed also in the production scale.
The aim of this work was to achieve uniformity of coating distribution on both pilot and production equipments; two different pan loading (medium and maximum) were considered on both scales.
Placebo oblong tablets (density 0.8 kg/L) providing mean weight of 850 mg were used as substrate for the drug layering. Tablets were coated in both pilot (Perfima Lab 30 litres, IMA) and production scale (Perfima 200 litres, IMA) using a water based coating formula containing Riboflavine as a drug tracer and Methocel E5 and PEG 6000 as polymer and plasticizer respectevely. The target weight gain was 10% by weight.
For all batches the coating distribution uniformity was determined calculating the coating Relative Standard Deviation (RSD) that has to be lower than 6% as reported in literature. In addition the coating thickness was assessed by Scanning Electron Microscopy (SEM) and the Riboflavine content was analysed by the HPLC method. Coating losses were also calculated for all batches.
In the preliminary part of the study 10 batches were performed on pilot equipment to identify the critical process parameters (process time, pan speed, atomisation pressure, gun distance, pan loading) affecting the uniformity of coating distribution. The results showed that the optimal parameters combination obtained for both medium (12kg) and maximum (25 kg) pan loading allowed to obtain a good coating distribution as demonstrated by the coating RSD values always lower than 6%. Coating losses resulted 10,8% and 11,5% for 12 kg and 25 kg respectively.
Up-scaling the drug layering process, two batches of 125 kg (medium pan loading) and 160 kg (maximum pan loading) were produced. The results showed that utilising the atomisation pressure, gun distance and total process time equal to the pilot scale batches and modifing the inlet air temperature, inlet air temperature quantity, pan speed and number of guns, the coating uniformity was mantained.%
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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