Cette thèse concerne l’étude des contacts pivotants rencontrés à la conjonction collet-rouleau, entre la bague d’un roulement et le flanc d’un rouleau. L’orientation principale de l’écoulement du lubrifiant peut changer lorsque le contact est mis à l’oblique. Cette cinématique complexe influe sur le comportement du contact. Elle est donc étudiée par une approche duale, expérimentale et numérique. Le banc d’essai Tribogyr permet l’expérimentation du contact à l’échelle 1:1. Une méthode pour la mesure de l’épaisseur du film lubrifiant par interférométrie optique en lumière blanche a été développée sur le banc d’essai et rend possible la mesure d’épaisseurs entre 0 et 800 nm, avec une résolution de quelques nanomètres. La mesure des efforts dans le sens de l’écoulement montre des similitudes avec les contacts de type roulement-glissement bien que le coefficient de frottement soit globalement plus faible. Les efforts transverses ont des valeurs du même ordre de grandeur que les efforts longitudinaux. Ils sont dus au cisaillement transverse induit par le pivotement. Un modèle numérique a été développé dans le but de simuler ces contacts pivotants. Le modèle inclut le calcul des températures et la rhéologie non Newtonienne du lubrifiant dans une stratégie de résolution par éléments finis, totalement couplée. La validation avec des résultats expérimentaux issus de Tribogyr, en épaisseur de film et en frottement, a été effectuée. Il est montré que l’épaisseur de film chute lorsque le pivotement et l’obliquité cisaillent le fluide, entraînant des effets rhéo-fluidifiants et thermo-fluidifiants. En cas de fort pivotement, le lubrifiant sortant peut être réinjecté à nouveau vers l’intérieur du contact et les transferts de chaleur entre lubrifiant et solides en sont fortement perturbés. Une forte obliquité entraîne à la fois la formation d’une augmentation locale de l’épaisseur de film et peut aussi provoquer la sous-alimentation du contact. Plusieurs campagnes expérimentales couplées à l’utilisation intensive du modèle numérique ont permis de comprendre les phénomènes physiques entrant en jeu et de prévoir l’efficacité, en terme de pertes de puissance, d’un contact pivotant. / This thesis is devoted to the study of spinning contacts located in bearing between the roller-end and the ring flange. The main direction of the lubricant flow may change when the contact is subjected to skew. This complex kinematics influences the contact behaviour. A dual experimental-numerical approach is proposed to study this problem. The Tribogyr test-rig allows the experimentation of the contact at the 1:1 scale. A film thickness measurement method, based on white light interferometry, was developed on Tribogyr. This method allows the measurement of film thickness between 0 and 800 nm with an accuracy of a few nanometres. The measurement of forces in the main flow direction shows similarities with classical rolling-sliding contacts. However, the friction coefficient is globally lower as soon as spin is involved. Transverse forces are of the same order of magnitude as the longitudinal forces. This is due to transverse shearing caused by the spin. A numerical model has been developed for the simulation of these spinning contacts. The finite element model, which is based on a fully-coupled solving strategy, takes into account the temperature calculation and the lubricant non-Newtonian rheology. Its validation with Tribogyr experimental results in terms of film thickness and friction has been conducted. Spin and skew effects induce high shear-thinning and thermal-thinning of the lubricant that lead to a decrease of the film thickness. Under high spinning condition, the lubricant exiting the contact may be re-injected to the contact inlet. Consequently, the heat transfers between the lubricant and the solids in contact are modified. In contact subjected to high skew, a local increase (dimple) of the film thickness may occur. Important skew may also lead to starvation conditions. Many experimental campaigns, coupled with an intensive use of the numerical model, allowed to understand the physical phenomena involved as well as to predict the efficiency, in terms of power losses, of the spinning contacts.

The industrial world is in constant demand for faster, cheaper and higher quality manufacturing. Robot utilisation and automation has evolved to become a necessary asset to master in order to stay competitive in the global market. With the growing dependency on robots, unexpected downtime and brakedowns can cause devastating loss of revenue. Consequently, this has lead to an increased importance for an accurate condition based way of performing robotic maintenance. As of writing, robots are predominantly maintained through time dependent maintenance. Part replacement is based on statistical models where maintenance is performed without taking the actual robot condition into consideration. As a result an overall level of uncertainty is ensued, where lacking the ability to properly diagnose the robot, also leads to superfluous repairs. Because of the costly impact this has on production, a condition based maintenance approach to robots would yield increased reliability at a lower cost of maintenance. This research focuses on trying to monitor vibrations in a robot, so as to infer about wear and to provide a first step in vibration based Robot Condition Monitoring. This research has been of multidisciplinary nature where robotics, tribology, mechanical component, signal analysis and diagnosis theory have overlapped in several areas throughout the project. The research has provided a vibration baseline and trends of the theoretical bearing defect frequencies for a hypocycloid gearbox installed on an ABB IRB6600 robot. The gearbox was not worn to a level that a severe gearbox degradation was irrefutably detectable and analysable. Accelerometers normally used on wind turbines were used for the project, and are believed to be sufficiently successful in capturing bearing related signals to accredit it for continued use at the preliminary stages of Robot Condition Monitoring development. A worn RV410F hypocycloid gearbox, was dismantled and analysed. Bearings found inside indicate high degrees of moisture corrosion and extensive surface wear. These findings had decisive roles in what future work recommendations where presented. Areas with great potential are condition monitoring through the use of Acoustic Emission and lubrication analysis. Further recommendations include investigating signal analysis techniques such as cepstrum pre-whitening and discrete wavelet transforms.

Enhanced oral activity is induced in neonatal 6-hydroxydopamine- (6-OHDA-) lesioned rats by systemic administration of the dopamine (DA) D1 receptor agonist SKF 38393 and serotonin (5-HT) 5-HT2A,2C agonist m-chlorophenylpiperazine (m-CPP). The DA D1 receptor antagonist SCH 23390 effectively attenuates the effect of SKF 38393 but not m-CPP. The 5-HT2antagonist mianserin attenuates the effects of both m-CPP and SKF 38393, suggesting that DA agonist effects are mediated by 5-HT neurochemical systems. To test whether DA and 5-HT agonist effects and interactions might occur within the neostriatum, rats were implanted with permanent injection cannulae, with tips in the ventral striatum. One group of rats was lesioned at 3 days after birth with 6-OHDA HBr (100 μg salt form, in each lateral ventricle; desipramine HCl pretreatment, 20 mg/kg IP, base form, 1 h), while controls received the vehicle in place of 6-OHDA. Cannulae were implanted when rats weighed 200-250 g. During a 1-h observation session SKF 38393 (5 nmol per side) produced 74.3±19.2 oral movements in intact rats and 310.7±97.0 oral movements in 6-OHDA-lesioned rats. m-CPP (10 nmol per side) produced 72.6±15.1 and 274.5±65.0 oral movements in these respective groups. These responses were several-fold greater than the 25.3±7.3 and 41.8±9.5 oral movements in the same groups after saline (0.5 μl per side) (P<0.05). Mianserin (6 nmol per side) alone had no effect on oral activity but attenuated responses to both SKF 38393 and m-CPP in intact and 6-OHDA-lesioned rats. These findings demonstrate that enhanced oral activity responses are produced by intrastriatal SKF 38393 and m-CPP in neonatal 6-OHDA-lesioned rats. Also, when the 5-HT2 receptor antagonist mianserin was administered intrastriatally, induction of oral activity by the DA D1 agonist SKF 38393 was attenuated. These findings indicate that ventral striatum represents at least one brain focus at which DA and 5-HT systems interact to modulate oral activity in rats.

Neonatal 6-hydroxydopamine (6-OHDA) treatment of rats is associated with concurrent supersensitization of dopamine (DA) D1 and serotonin 5-HT1C receptors, for agonist-induced oral activity. The present study was conducted to determine if graded reduction of striatal DA content and/or graded elevation of striatal 5-HT content by 6-OHDA would alter sensitivity of either receptor type, and thereby influence oral activity responses to DA and 5-HT agonists. At 3 days after birth, groups of rats were pretreated with desipramine (20 mg/kg i.p.), 1 h before administration of a range of doses of 6-OHDA HBr (15, 30, 60, 100, 150 and 200 μg, i.c.v., salt form; half in each lateral ventricle) or the vehicle, saline (0.85%)-ascorbic acid (0.1%). Between 2 and 4 months, a series of challenge doses of SKF 38393 HCl (0.30 to 3.0 mg/kg i.p.) and m-chlorophenylpiperazine 2HCl (0.30 to 6.0 mg/kg i.p.; m-CPP 2HCl) were administered to each group of rats and oral activity was observed. Oral activity was determined for 1 min every 10 min during a 60-min period, starting 10 min after injection of agonist or vehicle. SKF 38393 dose-response curves demonstrated enhanced oral activity responses in rats lesioned neonatally with 150 or 200 μg of 6-OHDA. m-CPP dose-response curves demonstrated enhanced oral activity responses in these 2 groups of rats, as well as those lesioned neonatally with 100 μg of 6-OHDA. Striatal DA content was reduced by > 97% in these 3 groups of rats. Striatal 5-HT content was elevated by > 80% in rats treated neonatally with 150- or 200-μg doses of 6-OHDA, and by 50% in rats treated neonatally with the 100-μg dose of 6-OHDA. Lower doses of 6-OHDA produced less of an effect on striatal DA and 5-HT content. Regression analysis determined that both SKF 38393- and m-CPP-induced oral activities were most closely correlated with the magnitude of change in striatal content of DA. These findings demonstrate that 5-HT agonist responses can be enhanced when DA agonist responses are not enhanced. Also, in neonatal 6-OHDA-lesioned rats the extent of DA depletion vs. the extent of 5-HT elevation seems to be a critical factor in the enhanced behavioral effects of DA and 5-HT agonists.

l-Prolyl-l-leucyl-glycinamide (MIF-1) is known to attenuate apomorphine-induced stereotypies in adult rats that are lesioned as neonates with 6-hydroxydopamine (6-OHDA). To test whether MIF-1 would affect dopamine (DA) agonist-induced and serotonin (5-HT) agonist-induced oral activity, both intact and neonatal 6-OHDA-treated rats were studied. Rats at 3 days from birth were injected with desipramine (20 mg/kg, IP), 1 h before 6-OHDA HBr (100 μg, salt form, in each lateral ventricle) or its vehicle, saline-ascorbic acid (0.1%). At approximately 6 months rats were treated with MIF-1 (0.1, 1.0, or 10.0 mg/kg, IP), 10 min before SKF 39393 HCl (1.0 mg/kg, IP) or m-chlorophenylpiperazine 2HCl (m-CPP 2HCl; 0.5 mg/kg, IP), DA D1 and 5-HT1C,2 receptor agonists, respectively. Although both agonists increased oral activity in control and neonatal 6-OHDA-treated rats, MIF-1 did not modify the response. In rats that received either of the three doses of MIF-1 for 21 consecutive days, there was still no observed effect of MIF-1 on the oral response of control and 6-OHDA-lesioned rats to SKF 38393 and m-CPP. These findings indicate that MIF-1 does not modify the oral activity response of supersensitized D1 and 5-HT1C receptors in adult rats that are lesioned neonatally with 6-OHDA.

On the morning of the first day of pregnancy, Wistar rats were administered a single IP injection of either zinc sulfate (10.0 mg/kg) or saline. For the remainder of pregnancy, half the rats in each group then consumed filtered tap water while the other half consumed filtered tap water with 50 ppm of cadmium (CdCl2). At eight weeks after birth, the behavioral profile of male offspring was assessed in the following way: Apomorphine (non-selective dopamine receptor agonist), (+)-7-hydroxy-2-(di-n-propylamino) tetralin (7-OH-DPAT) (D3 agonist) and (+/-)-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzazepine-7,8-diol (SKF 38393) (D1 agonist) were used to evaluate stereotyped behavior, yawning activity and oral movements - indices for these respective agonists. In addition, two dopamine receptor antagonists, haloperidol (D2 antagonist) and 7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-(1H)-3-benzapine (SCH 23390) (D1 antagonist) were used to evaluate cataleptogenic activity. Additional behavioral parameters studied were locomotor activity, irritability and reaction to a painful stimulus. Dopamine and its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA) and 3-methoxytyramine (3-MT) were quantified in the striatum, hippocampus and in the frontal cortex of the brain by means of HPLC/ED technique. In addition, cadmium levels were analyzed in the brain, liver, kidney and bone of newborn rats. Our results indicate that prenatal exposure of pregnant rats to cadmium produced alterations in the reactivity of central dopamine receptors and modulated the level of dopamine and its metabolites in the offsprings' brains. A single injection of zinc, preceding cadmium consumption, attenuated some of the effects of cadmium on the offsprings' dopaminergic system. Zinc also reduced cadmium deposition in the brain, kidney and bone, but enhanced its accumulation in liver. In summary, zinc may exert some neuroprotective effects against cadmium neurotoxicity.

No description available.

Abstract: To study potential biochemical correlates of dopamine (DA) and serotonin receptor supersensitivity, rats were lesioned at 3 days after birth with 6‐hydroxydopamine (6‐OHDA; 67 µg in each lateral ventricle; desipramine pretreatment, 20 mg/kg i.p., 1 h) and then sensitized with the DA D1 agonist, SKF 38393 HCl (3.0 mg/kg i.p. per day) either ontogenetically (daily, for 28 consecutive days from birth) and/or in adulthood (four weekly injections, 6–9 weeks from birth). Controls received vehicle in place of 6‐OHDA or SKF 38393. Enhanced locomotor responses were observed after SKF 38393 at 6 weeks, only in rats that received SKF 38393 + 6‐OHDA in ontogeny. Locomotor responses were further enhanced in this group after the last of four weekly SKF 38393 injections at the 9th week. These weekly SKF 38393 treatments also produced enhanced responses in 6‐OHDA rats that did not receive SKF 38393 in ontogeny. When striata were studied at 11 weeks, the percentages of high and low affinity DA D1 binding sites were not altered. Basal as well as DA‐, NaF‐, and forskolin‐stimulated adenylyl cyclase activities also were not changed. Dot blot analysis showed that there was a reduction of mRNA levels for DA D1, but not serotonin1C, receptors in the 6‐OHDA groups. However, SKF 38393 at 6–9 weeks eliminated this alteration. Based on these findings it can be proposed that supersensitization may be a consequence of altered neuronal cross talk rather than an imbalance of receptor elements per se.

Most multinational enterprises face difficulties regarding what and how to best communicate activities related to corporate social responsibility. Therefore, this master thesis addresses the online communication of corporate social responsibility by Swedish multinational enterprises. The purpose is to contribute to the understanding of the way Swedish multinational enterprises reveal messages regarding corporate social responsibility to their international stakeholders while communicating with them online via their websites and social media. This research is of qualitative nature and follows a multiple case study design. The six Swedish MNEs the Volvo Group, H&amp;M, Atlas Copco, Securitas AB, Svenska Kullagerfabriken, and Svenska Cellulosa AB are included in the sample. Two methods for data collection are combined: online observation of the communication regarding corporate social responsibility on the corporate websites including sustainability reports or alike and in social media as well as qualitative, semi-structured interviews with the employees in charge of corporate social responsibility. The results indicate that the examined multinational enterprises communicated corporate social responsibility in different ways depending on whether they communicate via their corporate websites, their reports or in social media. This master thesis concludes with practical recommendations for multinational enterprises involved in communication of corporate social responsibility.

Nitric acid has been implicated in a variety of physiological functions of the mammalian brain, and in a large number of its pathologies. Recently we have demonstrated that a nitric oxide donor (L-arginine) and a nitric-oxide-synthase-inhibitor (nitro-L-arginine-methyl-ester) modified the response of central al dopamine D 1 and D 3 receptors to some of their agonists. In the present study we demonstrate the modulatory effect of L-arginine, nitro-L-arginine-methyl-ester and molsidomine (another nitric oxide donor) on the reactivity of the central dopamine receptors to specific agonists and antagonists. The agonists tested were SKF-38393, 7-OH-DPAT and quinpirole, and the antagonists - SCH-23390 and haloperidol. They were evaluated in the rat by the following behavioral methods: locomotor activity, locomotor coordination, rearings and cataleptogenic activity (D 2 modulation); grooming time (D 1 activation); yawning (D 3 activation) and ethanol- and phenobarbital-sleeping-time parameters after SKF-38393 or quinpirole pretreatment. Our results suggest that nitro-L-arginine-methyl-ester is effective in modulating the reactivity of the central dopamine receptors D 2, D 1 and D 3, to their agonists and antagonists, and that it is much more effective than L-arginine in regulating the righting reflex after ethanol and phenobarbital, in both female and male mature rats.