The use of branched ketenedimers in solving the deposit problems related to the internal sizing of uncoated fine paper

Alkyl ketene dimers (AKD) are effective and highly hydrophobic sizing agents for the internal sizing of alkaline papers, but in some cases they may form deposits on paper machines and copiers. In addition, alkenyl succinic anhydrides (ASA)- based sizing agents are highly reactive, producing on-machine sizing, but under uncontrolled wet end conditions the hydrolysis of ASA may cause problems. This thesis aims at developing an improved ketene dimer based sizing agent that would have a lower deposit formation tendency on paper machines and copiers than a traditional type of AKD. The aim is also to improve the ink jet printability of a AKD sized paper. The sizing characteristics ofketene dimers have been compared to those of ASA. A lower tendency of ketene dimer deposit formation was shown in paper machine trials and in printability tests when branched fatty acids were used in the manufacture of a ketene dimer basedsizing agent. Fitting the melting and solidification temperature of a ketene dimer size to the process temperature of a paper machine or a copier contributes to machine cleanliness. A lower hydrophobicity of the paper sized with branched ketene dimer compared to the paper sized with traditional AKD was discovered. However, the ink jet print quality could be improved by the use of a branched ketene dimer. The branched ketene dimer helps in balancing the paper hydrophobicity for both black and color printing. The use of a high amount of protective colloidin the emulsification was considered to be useful for the sizing performance ofthe liquid type of sizing agents. Similar findings were indicated for both the branched ketene dimer and ASA.

Paperin pintaenergian vaikutus painovärin tarpeeseen

Työn tavoitteena oli selvittää pintaenergian vaikutus painovärin tarpeeseen IGT-laboratoriopainokoneella. Lisäksi selvitettiin onko karheudella vaikutusta kontaktikulmamittaukseen. Työ koostui kirjallisuusosasta ja kokeellisesta osasta. Kirjallisuusosassa tarkasteltiin aihepiiriä koskevia teorioita ja aiempia tutkimuksia. Kokeellisessa osassa valmistettiin laboratoriomittakaavassa pintaenergialtaan ja karheudeltaan erilaisia papereita. Pintaenergiaa muuteltiin kolmen erilaisen massaliiman ja kahden erilaisen pintaliiman avulla. Paperin karheutta säädettiin kalanteroinnilla. Papereista mitattiin pintaominaisuuksia, nesteen ja paperin välinen kontaktikulma, sekä suoritettiin painatuskokeita. Pintaenergia laskettiin kirjallisuudesta löytyneiden teorioiden perusteella ja näiden pintaenergian laskemismenetelmien käyttökelpoisuutta pintaenergian määrittämiseen selvitettiin. Lisäksi tutkittiin pintaenergian vaikutusta painovärin tarpeeseen. Tämä työ selvästi osoittaa, että yhden, kahden ja kolmen komponentin menetelmällä ja nesteitä vaihtelemalla saadaan erilaisia pintaenergian tuloksia. Pintaenergian määrittämiseen vaikuttaa myös kontaktikulmamittausten hankaluus ja kontaktikulman suuri vaihtelu, joka vaikuttaa koko mittaussarjan luotettavuustarkasteluun. Lisäksi paperin karheudella ja huokoisuudella oli merkitystä kontaktikulmamittaukseen.

Kemikaalisekoituksen vaikutus kartongin liimausasteen pienimittakaavaiseen vaihteluun

Tässä diplomityössä tutkittiin massaliimauksen stabiilisuutta kartonkikoneella ja himan sekoituskonseptin muuttamisen vaikutusta liimausasteeseen ja liimausasteen pienimittakaavaiseen vaihteluun konerullan sisällä. Koeajoista saadut tulokset olivat erittäin lupaavia. Koeajoissa annosteltiin hartsia kahdella eri TrumpJet™-installaatiolla. Ensimmäisessä koeajossa hartsi sekoitettiin kaikkiin kolmeen kerrokseen sakean massan syöttölinjaan, ennen pyörrepuhdistuksen vaatimaa laimennusta. Toisessa koeajossa hartsi annosteltiin kolmella TrumpJet-suuttimella kartongin pintakerrokseen konesihdin jälkeen ja muihin kerroksiin perinteisesti sekoitussäiliön. Tuloksista nähtiin, että hartsin syöttö perälaatikon lähestymisvirtaukseen on mahdollista kartongin laadun ja liimausasteen siitä karsimatta. Liimausaste määritettiin Stora Enson spesifisen REP-menetelmän (raw edge penetration) avulla. Koesarjojen välille ei syntynyt merkittäviä eroja reunaimeytymätasoihin, eikä koesarjojen sisäisiin vaihteluihin verrattaessa referensikonerulliin.

Kartongin reunaimeytymän hallittavuus

Kuppikartongin yksi tärkeimmistä ominaisuuksista on reunaimeytymän vastustuskyky, joka tulee olla riittävällä tasolla laadun takaamiseksi. Koska yksinkertainen juomakuppi on bulkki¬tuote, ei sen raakareunaa kannata taloudellisuuden vuoksi suojata tätä varten kehitellyillä menetelmillä vaan itse kartongin tulee vastustaa nesteitä riittävässä määrin. Tämän diplomityön tarkoituksena oli selvittää hydrofobointiin käytettävän massaliiman (hartsi) sekä pintaliiman joukkoon annosteltavan lisäaineen välinen optimaalinen suhde parhaan vastustuskyvyn saavuttamiseksi. Lisäksi selvitettiin joidenkin liimapuristimen ajo-olosuhteiden vaikutusta pintaliiman pick-upiin sekä koneen pH-tason oikeellisuus. Jauhatuksen vaikutusta tutkittiin lähinnä historiatietojen avulla. Tutkimus koostui viidestä tehdasmittakaavaisesta koeajosta, joiden avulla selvitettiin muuttujien vaikutus sisäisellä reunaimeytymän määritysmenetelmällä sekä määrittä¬mällä koepisteistä kulloinkin mielenkiinnon kohteena olleet kemikaalipitoisuudet. Viimeisen koeajon koepisteet jalostettiin lisäksi valmiiksi kupeiksi. Käytetty reunaimeytymän määritysmenetelmä osoittautui virhealttiiksi eivätkä raakakartongista tehtyjen määritysten tulokset korreloineet kovinkaan voimakkaasti PE-päällystettyjen näytteiden kanssa. Menetelmän kehitystä on viety eteenpäin tämän työn rinnalla ja työ jatkuu edelleen. Lisäksi kartongin hartsipitoisuusmääritysten tuloksista paljastui ristiriitaisuuksia, joiden vuoksi menetelmää uusittiin voimakkaasti. Reunaimeytymän vastustuksen riittävyydeksi koneella käytettävien massaliima-annosten tulee olla vähintään valitulla nollatasolla kaikissa kerroksissa ja pintaliiman lisäaine tulee pitää käytössä. Mikäli lisäaine jätetään pois käytöstä, tulee massaliima-annokset olla hyvin korkeita, eikä tämäkään takaa täysin reunaimeytymätöntä lopputuotetta. Lisäaineen ollessa käytössä ei suuremmalla massaliima-annoksella ole puolestaan merkittävää vaikutusta. Konetta ajetaan nykyisin hyvin alhaisella pH-tasolla, mutta tason nostaminen aiheuttaa selvän liimauksen heikkenemisen. Liimapuristimelle tulevan radan kosteudella ja pintaliiman kuiva-aineella ei näyttäisi olevan vaikutusta kartongin reunaimeytymän vastustuskykyyn. Myöskään taustakerroksen koivun jauhatusasteella ei ole merkitystä alueella, jolla koneella operoidaan. CTMP-massan jauhatuksen tulee sen sijaan olla riittävä, jotta keskikerrokseen ei synny yksittäisiä, pitkiä imeytymiä.

Análise do pré-mix de breu esterificado e policloreto de alumínio como agente de colagem interna em sistemas alcalinos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comparison Of Postoperative Stability Of Three Rigid Internal Fixation Techniques After Sagittal Split Ramus Osteotomy For Mandibular Advancement.

The aim of this investigation was to compare the skeletal stability of three different rigid fixation methods after mandibular advancement. Fifty-five class II malocclusion patients treated with the use of bilateral sagittal split ramus osteotomy and mandibular advancement were selected for this retrospective study. Group 1 (n = 17) had miniplates with monocortical screws, Group 2 (n = 16) had bicortical screws and Group 3 (n = 22) had the osteotomy fixed by means of the hybrid technique. Cephalograms were taken preoperatively, 1 week within the postoperative care period, and 6 months after the orthognathic surgery. Linear and angular changes of the cephalometric landmarks of the chin region were measured at each period, and the changes at each cephalometric landmark were determined for the time gaps. Postoperative changes in the mandibular shape were analyzed to determine the stability of fixation methods. There was minimum difference in the relapse of the mandibular advancement among the three groups. Statistical analysis showed no significant difference in postoperative stability. However, a positive correlation between the amount of advancement and the amount of postoperative relapse was demonstrated by the linear multiple regression test (p < 0.05). It can be concluded that all techniques can be used to obtain stable postoperative results in mandibular advancement after 6 months.

Development Plates For Stable Internal Fixation: Study Of Mechanical Resistance In Simulated Fractures Of The Mandibular Condyle.

To develop Y-shaped plates with different thicknesses to be used in simulated fractures of the mandibular condyle. Ten plates were developed in Y shape, containing eight holes, and 30 synthetic polyurethane mandible replicas were developed for the study. The load test was performed on an Instron Model 4411 universal testing machine, applying load in the mediolateral and anterior-posterior positions on the head of the condyle. Two-way ANOVA with Tukey testing with a 5% significance level was used. It was observed that when the load was applied in the medial-lateral plate of greater thickness (1.5 mm), it gave the highest strength, while in the anteroposterior direction, the plate with the highest resistance was of the lesser thickness (0.6 mm). A plate with a thickness of 1.5 mm was the one with the highest average value for all displacements. In the anteroposterior direction, the highest values of resistance were seen in the displacement of 15 mm. After comparing the values of the biomechanical testing found in the scientific literature, it is suggested that the use of Y plates are suitable for use in subcondylar fractures within the limitations of the study.

Permeability of different groups of maxillary teeth after 38% hydrogen peroxide internal bleaching

This study evaluated the influence of internal tooth bleaching with 38% hydrogen peroxide (H2O2) on the permeability of the coronal dentin in maxillary anterior teeth and premolars. Seventy teeth (14 per group) were used: central incisors (CI), lateral incisor (LI), canines (C), first premolars (1PM) and second premolars (2PM). Pulp chamber access and transversal sectioning at 2 mm from the cementoenamel junction were performed and the specimens were divided into 2 groups (n= 7): a) no treatment and b) bleaching with 38% H2O2. The bleaching agent was applied to the buccal surface and to the pulp chamber for 10 min. This procedure was repeated 3 times. The specimens were processed histochemically with copper sulfate and rubeanic acid, sectioned longitudinally, and digitalized in a scanner. The area of stained dentin was measured using Image Tool software. Data were analyzed statistically by ANOVA and Tukey's HSD test (?=0.05). There was statistically significant difference (p<0.001) among the untreated groups, CI (0.23 ± 0.26) having the lowest permeability and LI (10.14 ± 1.89) the highest permeability. Among the bleached groups, dentin permeability was increased in all groups of teeth except for 2PM. It may be concluded that bleaching with 38% H2O2 affected dentin permeability near the pulp chamber in maxillary anterior teeth and in first and second premolars.

A hybrid heuristic for the multi-plant capacitated lot sizing problem with setup carry-over

This paper addresses the capacitated lot sizing problem (CLSP) with a single stage composed of multiple plants, items and periods with setup carry-over among the periods. The CLSP is well studied and many heuristics have been proposed to solve it. Nevertheless, few researches explored the multi-plant capacitated lot sizing problem (MPCLSP), which means that few solution methods were proposed to solve it. Furthermore, to our knowledge, no study of the MPCLSP with setup carry-over was found in the literature. This paper presents a mathematical model and a GRASP (Greedy Randomized Adaptive Search Procedure) with path relinking to the MPCLSP with setup carry-over. This solution method is an extension and adaptation of a previously adopted methodology without the setup carry-over. Computational tests showed that the improvement of the setup carry-over is significant in terms of the solution value with a low increase in computational time.

Internal and external time conflicts in adolescents: sleep characteristics and interventions

Daytime fatigue and lack of sleep seem to increase throughout adolescent years. Several environmental, psychological, and biological factors have been associated with the development of sleep across adolescence. The aim of the present article is to summarize these factors and to give examples of various outcomes in sleep patterns among adolescents studied in different cultural settings. It is obvious from earlier work that many adolescents have displaced circadian rhythms and lack of adaptation to school hours due to an early school start or additional burdens for work. Several interventions have aimed to help the adaptation process by supporting sleep processes and changing scheduling, in this way promoting classroom alertness. In summary, adolescents worldwide shorten their sleep due to schoolwork hours and additional work, especially by disturbing their sleep due to circadian misalignment

Highlights from the I international symposium of thrombosis and anticoagulation in internal medicine, October 23–25, 2008, Sao Paulo, Brazil

Abstract The importance of thrombosis and anticoagulation in clinical practice is rooted firmly in several fundamental constructs that can be applied both broadly and globally. Awareness and the appropriate use of anticoagulant therapy remain the keys to prevention and treatment. However, to assure maximal efficacy and safety, the clinician must, according to the available evidence, choose the right drug, at the right dose, for the right patient, under the right indication, and for the right duration of time. The first International Symposium of Thrombosis and Anticoagulation in Internal Medicine was a scientific program developed by clinicians for clinicians. The primary objective of the meeting was to educate, motivate and inspire internists, cardiologists and hematologists by convening national and international visionaries, thought-leaders and dedicated clinician-scientists in Sao Paulo, Brazil. This article is a focused summary of the symposium proceedings

Internal stresses and textures of nanostructured alumina scales growing on polycrystalline Fe(3)Al alloy

The evolution of internal stresses in oxide scales growing on polycrystalline Fe(3)Al alloy in atmospheric air at 700 degrees C was determined using in situ energy-dispersive synchrotron X-ray diffraction. Ex situ texture analyses were performed after 5 h of oxidation at 700 degrees C. Under these conditions, the oxide-scale thickness, as determined by X-ray photoelectron spectroscopy, lies between 80 and 100 nm. The main phase present in the oxide scales is alpha-Al(2)O(3), with minor quantities of metastable theta-Al(2)O(3) detected in the first minutes of oxidation, as well as alpha-Fe(2)O(3). alpha-Al(2)O(3) grows with a weak (0001) fiber texture in the normal direction. During the initial stages of oxidation the scale develops, increasing levels of compressive stresses which later evolve to a steady state condition situated around -300 MPa. (C) 2010 International Centre for Diffraction Data. [DOI: 10.1154/1.3402764]

Effect of the effluent released from the canine internal mammary artery after intraluminal and extraluminal perfusion of acetylcholine and adenosine diphosphate

Segments of the canine internal mammary artery (35 mm in length) were suspended in vitro in an organ chamber containing physiological salt solution (95% O(2)/5% CO(2), pH = 7.4, 37 degrees C). Segments were individually cannulated and perfused at 5 ml/minute using a roller pump. Vasorelaxant activity of the effluent from the perfused internal mammary arteries was bioassayed by measuring the decrease in tension induced by the effluent of the coronary artery endothelium-free ring which had been contracted with prostaglandin F(2 alpha) (2 x 10(-6) M). Intraluminal perfusion of adenosine diphosphate (10(-5) M) induced significant increase in relaxant activity in the effluent from the perfused blood vessel. However, when adenosine diphosphate (10(-5) M) was added extraluminally to the internal mammary artery, no change in relaxant activity in the effluent was noted. In contrast, acetylcholine produced significant increase in the relaxant activity on the effluent of the perfused internal mammary artery with both intraluminal and extraluminal perfusion. The intraluminal and extraluminal release of endothelium-derived relaxing factor (EDRF) by acetylcholine (10(-5) M) can be inhibited by site-specific administration of atropine (10(-5) M). These experiments indicate that certain agonists can induce the release of EDRF only by binding to intravascular receptors while other agonists can induce endothelium-dependent vasodilatation by acting on neural side receptors.

Internal Strain Distribution in Freestanding Porous Silicon

Elastic properties of freestanding porous silicon layers fabricated by electrochemical anodization were studied by Raman scattering. Different anodization currents provided different degrees of porosity in the nanometer scale. Raman lines corresponding to the longitudinal optical phonons of crystalline and amorphous phases were observed. The amorphous volume fraction increased and the phonon frequencies for both phases decreased with increasing porosity. A strain distribution model is proposed whose fit to the experimental results indicates that the increasing nanoscale porosity causes strain relaxation in the amorphous domains and strain buildup in the crystalline ones. The present analysis has significant implications on the estimation of the crystalline Si domain's characteristic size from Raman scattering data. (C) 2009 The Electrochemical Society. [DOI: 10.1149/1.3225832] All rights reserved.