Trigger and aperture of the surface detector array of the Pierre Auger Observatory

The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above 3 x 10(18) eV, for all zenith angles between 0 degrees and 60 degrees, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance. (C) 2009 Elsevier B.V. All rights reserved.

Atmospheric effects on extensive air showers observed with the surface detector of the Pierre Auger observatory

Atmospheric parameters, Such as pressure (P), temperature (T) and density (rho proportional to P/T), affect the development of extensive air showers initiated by energetic cosmic rays. We have Studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a similar to 10% seasonal modulation and similar to 2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of P and rho. The former affects the longitudinal development of air showers while the latter influences the Moliere radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory. (C) 2009 Elsevier B.V. All rights reserved.

Flerskiktat papper : en sammanställning av historia, teknik och forskningsresultat

Until the beginning of the 1900:th century the paper making process was handicraft. The paper machines that have been developed since then are as impressing in size as fascinating when it comes to the technique. The process has always been improved to give a better paper for lower costs, with as short manufacture time as possible. Stratified forming has been a reality since 1830. From the beginning it was applied to board and paperboard. Now it is also the most common method for making tissue and one paper mill in Austria use it for fine paper. Stratified forming can be categorized as separate forming or simultaneous forming. Separate forming means using several headboxes and sometimes even several wires. Simultaneous forming means using only one stratified headbox. This method has many advantages over separate forming, inter alia improved economy, quality, wood exchange and higher runability of the paper machine. Several experiments have been done with simultaneous forming of different fibres by placing a fibre with high bulk in the middle layer and a smooth fibre on the surface layers. The results has shown that by using this method both the bending stiffness and surface properties are improved, or a lower grammage paper is obtained with maintaining quality. Simultaneous forming can also be used to stratify fillers in layers where they are most efficient. In that way both paper quality and economy is improved. Simultaneous forming is also used for fractionated pulp. Fractionation means separating springwood fibre from summerwood fibre, and placing them in separate layers. Research results of fractionated pulp show about the same result as simultaneous forming of different fibres.

Visuell Perception : En studie av visuella faktorer kring ett musikaliskt framträdande

The essay investigates the visual element as seen by the audience and artist to be of greatest importance to a musicalperformance. The study was conducted in the form of a field work which included doing interviews with artists, surveys of the audience and interpretive observations of live performance. The fieldwork was conducted in three different environments in which I found myself on the spot and performed the various stages included in the field work. It was done to create a surface that could be used in an essay, and through that use this material to compare and analyze my results and in the end be able to answer my questions. I started from eight different factors which all could beexperienced visually on stage. The factors were light / colors, costumes, props, effects, stage presence, attitude / image, nervousness and dance / body language. Those factors would then be examined in the various musical performances and to be answered by the audience and performers which of those factors they considered to be of great importance or small importance when it comes to visual perception in a musical context. The result was a clear statement where two factors were considered to be most crucial for a musical performance, and a clear statement in which two factors were considered by the majority to be less important. The results demonstrate a common understanding what the artist and the audience thinks is important. A result that can act as a template for what an artist should think about regarding the visual elements before an performance. My theory is my assumption that the visual elements of musical performances can play an important or decisive role, an assumption that was strengthened by my empirical experiences at a concert visit. I wanted in this essay explore and give a clear picture of what it is that artists and audiences consider to be visually crucial for a musical context

Influence of surface texture on the galling characteristics of lean duplex and austenitic stainless steels

Two simulative test methods were used to study galling in sheet forming of two types of stainlesssteel sheet: austenitic (EN 1.4301) and lean duplex LDX 2101 (EN 1.4162) in different surface conditions. Thepin-on-disc test was used to analyse the galling resistance of different combinations of sheet materials and lubricants. The strip reduction test, a severe sheet forming tribology test was used to simulate the conditionsduring ironing. This investigation shows that the risk of galling is highly dependent on the surface texture of theduplex steel. Trials were also performed in an industrial tool used for high volume production of pumpcomponents, to compare forming of LDX 2101 and austenitic stainless steel with equal thickness. The forming forces, the geometry and the strains in the sheet material were compared for the same component.It was found that LDX steels can be formed to high strain levels in tools normally applied for forming ofaustenitic steels, but tool adaptations are needed to comply with the higher strength and springback of thematerial.

Kunskapsöverföring- att leda rätt : Ledarens roll vid kunskapsöverföring i en organisation

I en rapport som Svensk Näringsliv (2010) har utfört beskriver de att företag redan idag och inom en snar framtid står inför den största pensionsavgången någonsin i Svensk historia. 40- talisternas avgång ställer företag inför stora utmaningarna, framförallt att lyckas genomföra en lyckad generationsväxling. De personer som går i pension har under sitt yrkesverksamma liv utvecklat en kunskap som många organisationer vilar på. En stor del av denna kunskap måste överföras för att organisationerna ska kunna fortsätta att vara effektiva på marknaden. Syftet med denna studie var att få en djupare förståelse för ledarskapets betydelse gällande kunskapsöverföring i en organisation, samt bidra med praktiska verktyg till chefer och medarbetare för att undvika att förlora värdefull kunskap vid en generationsväxling. Industriföretaget LEAX har själva identifierat ett problem i att överföra viktig kunskap i och med kommande generationsväxling. Deras önskan var att få hjälp med praktiska verktyg för hur de ska tänka och verka för att mildra kunskapsglappet som kan uppstå. För att undersöka detta och därmed uppfylla denna studies syfte har intervjuer genomförts med fyra produktionsledare, fyra medarbetare som förväntas dela kunskap och tre medarbetare som förväntas ta till sig kunskap. Innan intervjuerna genomfördes läste vi in oss på teori om kunskap, kunskapsöverföring och ledarskap. Eftersom begreppet kunskap har en bred betydelse och kan definieras olika beroende om den är individuell eller organisatorisk, började vi i vårt teoriavsnitt att bena ut detta begrepp. Nonaka och Takeuchi (1995) gör en förenklad bild av kunskap som ett isberg, där den explicita kunskapen benämns som toppen. Väl synlig över ytan på vattnet är den enkel att upptäcka och ta till sig. Under vattnet döljer sig en osynlig kunskap som är svår att upptäcka, så kallas implicit eller tyst kunskap. Denna kunskap utgör en enorm del av isberget och blir därmed viktig att bevara. Dock är denna kunskap svår att överföra då den är osynlig och svår att ta på. För att förstå vad kunskapsöverföring innebär, behöver organisationer identifiera vilken sorts kunskap som behöver överföras för att kunskapsöverföringen ska bli lyckad (Jonsson, 2012). Men även fast organisationer gör detta måste även ledningen förstå att kunskapsöverföring är en strategisk angelägenhet som kan ses som en process som involverar medarbetare. I denna studie har vi undersökt hur ledare kan skapa motivation, engagemang och resurser för medarbetare att vilja medverka och bidra till kunskapsöverföring. För att försöka förstå hur kunskap överförs i en organisation har vi använt oss av Nonaka och Takeuchi, (1995) SECI-modell. Modellen bygger på samspelet mellan den tysta och explicita kunskapen, vilket sker i fyra processer. Dessa processer har vi sedan utvecklat till en egen modell som inkluderar institutionella, organisatoriska och kognitiva faktorer. Utifrån dessa faktorer har vi skapat praktiska förslag på hur ledare tillsammans med medarbetarna kan planera kunskapsöverföring. Dessa praktiska förslag gynnar både individuell- och organisatorisk utveckling, samt bidrar till att mildra kunskapsförlust vid generationsväxlingen. Ett av de praktiska exempel vi utformat är en kompetensprofil, som är ett hjälpmedel för organisationer att identifiera vilken kunskap som medarbetarna besitter, vilket synliggör vilken kunskap det är som kan gå förlorad. Kompetensprofilen tillsammans med vår modell kan appliceras på liknande företag, men även på organisationer som verkar inom andra branscher. Eftersom denna kompetensprofil är utvecklad efter de krav som finns inom aktuell verksamhet, finns det möjlighet att anpassa efter andra verksamheter.

Surface-enhanced raman scattering: metal nanostructures coated with langmuir-blodgett films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A DOE based approach for the design of RBF artificial neural networks applied to prediction of surface roughness in AISI 52100 hardened Steel turning

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efectos del parasitismo sobre el tejido branquial en peces cultivados: estudio parasitologico e histopatologico

One hundred four out of 225 diagnosticated cases were myxosporidian, monogenean, Ichthyophthirius multifiliis Fouquet, 1876 and bacterial diseases in Piaractus mesopotamicus Holmberg, 1887 (pacu), Colossoma macropomum Cuvier, 1818 (tambaqui) and tambacu, at Aquaculture Center, Universidade Estadual Paulista (UNESP), Jaboticabal, São Paulo, Brazil, between 1992 and 1995. The gills were fixed in 10% buffered formalin solution to posterior histologic routine. It was observed Henneguya sp. cysts into the capillaries of the secondary lamellae, encapsulated by the respiratory epithelium cells. It provoked adherence of the adjacent lamellae, hyperplasia, congestion, oedema and epithelium displacement. Monogeneans infestations by Anacanthorus penilabiatus Boeger, Husak & Martins, 1995 and Ancyrocephalinae sub-family caused light inflammatory reaction and hyperplasia. In severe infestations was observed hyperplasia of primary lamellae, necrosis, oedema, respiratory epithelium displacement, ruptured pillar cells and telangiectasis. Response to I. multifiliis was limited to surrounding epithelial cells in young fishes and hyperplasia, necrosis, inflammatory infiltrate and oedema in old fishes. Such lesions iniciate hyperplasic and oedematous process that with inflammation of the parasitic sites, provoked alterations over gases and ions interchange surface and consequently fish metabolism.

Effects of milling condition on the surface integrity of hot forged steel

This paper presents a study on the influence of milling condition on workpiece surface integrity focusing on hardness and roughness. The experimental work was carried out on a CNC machining center considering roughing and finishing operations. A 25 mm diameter endmill with two cemented carbide inserts coated with TiN layer were used for end milling operation. Low carbon alloyed steel Cr-Mo forged at 1200 degrees C was used as workpiece on the tests. Two kinds of workpiece conditions were considered, i.e. cur cooled after hot forging and normalized at 950 degrees C for 2 h. The results showed that finishing operation was able to significantly decrease the roughness by at least 46% without changing the hardness. on the other hand, roughing operation caused an increase in hardness statistically significant by about 6%. The machined surface presented deformed regions within feed marks, which directly affected the roughness. Surface finish behavior seems to correlate to the chip ratio given the decrease of 25% for roughing condition, which damaged the chip formation. The material removal rate for finishing operation 41% greater than roughing condition demonstrated to be favorable to the heat dissipation and minimized the effect on material hardness.

Caracterizacion metalografica de aleaciones metalicas utilizadas como biomateriales en implantes quirurgicos

In this work, the chemical structure, the microstructure and the surface morphology of two non-ferrous materials used in dental implants (Ti-6Al-4V and Co-Cr-Mo) were studied. This was done by chemical analysis, scanning electron microscopy (SEM), energy disperse spectroscopy (EDS), and strength measurements (HV). Metallographic studies reveal that titanium alloy surface present a fine granular binary phase structure, while cobalt alloy present cast dendrite structures with an intense precipitation of carbides. To correlate the macro and microstructure with the mechanical behavior of the material, microhardness measurements were performed. Using the Vickers hardening method, the Ti-6Al-4V alloy yielded strength mean values smaller than the Co-Cr-Mo alloy. Their values are associated to the chemical composition and to the microstructural distribution of these materials. The Ti-6Al-4V alloy presents hardness similar to dental enamel, which suggests better performance as dental implant.

Estudio de la pasivacion de la aleacion Co-Cr-Mo en suero fisiologico

Results are presented on the mechanism of passivation of Co-Cr-Mo biological implant alloys in physiological serum using open circuit potentiometry, potentiodynamic curves, and electrochemical impedance spectroscopy. The potential dependence of impedance data and the analysis of the parameters obtained indicate a progressive diminution of the initial layer thickness and the simultaneous formation of a second higher resistive layer. In more severe conditions than the existent in human body, the metallographic examination of the alloy surface shows localized corrosion in interdendritric regions. Elemental analysis of the surface reveals the presence of higher chromium content in these regions. The presence of chlorine was not detected, which suggested that during preferential attack, soluble species are also formed.

Root surface treatment with vitamin C in tooth replantation: microscopic study in rats

AIM: Late tooth replantation is a worthy procedure, especially in growing patients, being the best option for tooth avulsion. This study evaluated the effects of root surface treatment with 2% acidulated phosphate sodium fluoride and effervescent vitamin C (Redoxon) in late replantation. METHODS: Twenty rat teeth (Rattus norvegicus, albinus, Wistar) were extracted and left on a table for 6 h. Then, the dental papilla and enamel organ were sectioned and the pulp was removed through the apex. After removal of the periodontal ligament with a blade, the animals were divided into 2 groups: Group I teeth were immersed in 2% acidulated phosphate sodium fluoride solution for 10 min and obturated with Ca(OH)(2) paste. Group II teeth were immersed in effervescent vitamin C solution (Redoxon 2 g) for 10 min and obturated as for Group I. After these procedures, teeth were replanted and animals were killed after 60 days. RESULTS: The study revealed a larger amount of replacement resorption in Group I and larger amount of ankylosis in Group II, with statistically significant difference and absence of inflammatory resorption. CONCLUSION: The substances used for root surface treatment were unable to prevent replacement resorption and ankylosis, which are expected when the periodontal ligament has been lost.

Hallazgos clínico-radiológicos de la articulación temporomandibular en pacientes con artritis reumatoide

Aim of present paper is to describe and to assess the Clinicoradiological findings of the temporomandibular joint (TMJ) in a group of patients diagnosed with rheumatoid arthritis (RA). Sample included 61 patients with a mean age of 54 years and 5 months. All of them were interrogated and clinically examined and then underwent to a radiographic examination of both TMJs, using the transcranial projection technique, with the closed mouth and in maximal opening. Study includes the TMJ syndrome founded such as pain, tumefaction, luxation, clicking, and a limited oral opening. The study of radiographic features showed the presence of changes in condyle surface and temporal fossa, in condylar motility, and articulation space. We conclude that in patients presenting with rheumatoid arthritis is frequent the presence of clinicoradiological findings in the TMJ, and that patient's age and gender and the activity level and the RA course time, are factors influencing in TMJs general status.

Importancia del diagnóstico precoz de los lipomas de células grandes en la región maxilofacial

Lipoma is a benign tumor composed of proliferation of mature fat cells interspersed by fibrous connective tissue, blood vessels and muscles, delimited by a thin capsule. Although it represents a mesenchymal neoplasm most common human body, are rare occurrences in the oral cavity. Presents clinical and histopathological variables that do not alter their prognosis. The pathogenesis is still uncertain, although some authors consider heredity and endocrine disorders as possible causes. Occurs with greater prevalence in obese people, although their metabolism is completely independent of the normal body lipid metabolism. The clinical diagnosis of oral lipoma is the view of a nodular mass, soft, asymptomatic, flat surface, without ulceration and limited growth. The continuing growth of the lesion may cause difficulty in chewing, speech, dental adaptation and change in facial aesthetics of the patient, requiring surgical excision of the lesion. The final diagnosis is by histopathological examination. Aims to present a literature review and clinical cases of a retrospective study of 61 cases of lipomas diagnosed in pathological service between 1978 and 2009, among the 10 573 reports during that same period. It emphasizes the special cases of large lipomas of the maxillofacial region, and the importance of early diagnosis of these lesions. A dental surgeon should be able to diagnose lipomas in an early stage in the maxillofacial area avoiding a massive growth of these lesions.