Numerical and Experimental Investigation of Aircraft Panel Deformations During Riveting Process

In collaboration with Airbus-UK, the dimensional growth of aircraft panels while being riveted with stiffeners is investigated. Small panels are used in this investigation. The stiffeners have been fastened to the panels with rivets and it has been observed that during this operation the panels expand in the longitudinal and transverse directions. It has been observed that the growth is variable and the challenge is to control the riveting process to minimize this variability. In this investigation, the assembly of the small panels and longitudinal stiffeners has been simulated using static stress and nonlinear explicit finite element models. The models have been validated against a limited set of experimental measurements; it was found that more accurate predictions of the riveting process are achieved using explicit finite element models. Yet, the static stress finite element model is more time efficient, and more practical to simulate hundreds of rivets and the stochastic nature of the process. Furthermore, through a series of numerical simulations and probabilistic analyses, the manufacturing process control parameters that influence panel growth have been identified. Alternative fastening approaches were examined and it was found that dimensional growth can be controlled by changing the design of the dies used for forming the rivets.

A material model for multiaxial stretching and stress relaxation of polypropylene under process conditions

Polypropylene sheets have been stretched at 160 °C to a state of large biaxial strain of extension ratio 3, and the stresses then allowed to relax at constant strain. The state of strain is reached via a path consisting of two sequential planar extensions, the second perpendicular to the first, under plane stress conditions with zero stress acting normal to the sheet. This strain path is highly relevant to solid phase deformation processes such as stretch blow moulding and thermoforming, and also reveals fundamental aspects of the flow rule required in the constitutive behaviour of the material. The rate of decay of stress is rapid, and such as to be highly significant in the modelling of processes that include stages of constant strain. A constitutive equation is developed that includes Eyring processes to model both the stress relaxation and strain rate dependence of the stress. The axial and transverse stresses observed during loading show that the use of a conventional Levy-Mises flow rule is ineffective, and instead a flow rule is used that takes account of the anisotropic state of the material via a power law function of the principal extension ratios. Finally the constitutive model is demonstrated to give quantitatively useful representation of the stresses both in loading and in stress relaxation.

The Applicability of Two Strengths-based Systemic Psychotherapy Models for Young People Following Type 1 Trauma

This paper will consider the inter-relationship of a number of overlapping disciplinary theoretical concepts relevant to a strengths-based orientation, including well-being, salutogenesis, sense of coherence, quality of life and resilience. Psychological trauma will be referenced and the current evidence base for interventions with children and young people outlined and critiqued. The relational impact of trauma on family relationships is emphasised, providing a rationale for systemic psychotherapeutic interventions as part of a holistic approach to managing the effects of trauma. The congruence between second-order systemic psychotherapy models and a strengths-based philosophy is noted, with particular reference to solution-focused brief therapy and narrative therapy, and illustrated; via a description of the process of helping someone move from a victim position to a survivor identity using solution-focused brief therapy, and through a case example applying a narrative therapy approach to a teenage boy who suffered a serious assault. The benefits of a strength-based approach to psychological trauma for the clients and therapists will be summarised and a number of potential pitfalls articulated.

Mother's Narratives of Trauma: An exploratory study of how mothers' narrate the impact of trauma on their families

This study explored the narratives of 10 mothers whose families had been impacted by potentially traumatising events. The study was set in the context of Post-Traumatic Stress Disorder (PTSD), a relatively narrow psychiatric construct, which currently dominates much professional discourse and practice in traumatology, but references literature that provides a theoretical rationale for a broader approach. Narrative Interviewing methodology was employed and mothers of families referred to a specialist clinical service were interviewed prior to professional therapeutic intervention. The 10 mothers' narratives were analysed thematically via a rigorous process involving two independent analysts and the data organised into an evolving theoretical framework of themes and supra-themes. As hypothesised, PTSD symptomatology constituted a small proportion of the mothers' narratives (6.2%). The major components of the narratives included family and relational distress (35.7%), non-pathological individual distress (24.4%), resilience (16.7%) and a prior history of adversity (16.6%). Although exploratory in nature, the results of this study are sufficiently strong to warrant further investigation and raise tentative questions regarding the appropriateness of many existing therapeutic services for people impacted by trauma.

Investigation of Aircraft Panel Deformations during Riveting Process

In collaboration with Airbus-UK, the dimensional growth of small panels while being riveted with stiffeners is investigated. The stiffeners have been fastened to the panels with rivets and it has been observed that during this operation the panels expand in the longitudinal and transverse directions. It has been observed that the growth is variable and the challenge is to control the riveting process to minimize this variability. In this investigation, the assembly of the small panels and longitudinal stiffeners has been simulated using low and high fidelity nonlinear finite element models. The models have been validated against a limited set of experimental measurements; it was found that more accurate predictions of the riveting process are achieved using high fidelity explicit finite element models. Furthermore, through a series of numerical simulations and probabilistic analyses, the manufacturing process control parameters that influence panel growth have been identified. Alternative fastening approaches were examined and it was found that dimensional growth can be controlled by changing the design of the dies used for forming the rivets.

Stable Isolated Metal Atoms as Active Sites for Photocatalytic Hydrogen Evolution

The process of using solar energy to split water to produce hydrogen assisted by an inorganic semiconductor is crucial for solving our energy crisis and environmental problems in the future. However, most semiconductor photocatalysts would not exhibit excellent photocatalytic activity without loading suitable co-catalysts. Generally, the noble metals have been widely applied as co-catalysts, but always agglomerate during the loading process or photocatalytic reaction. Therefore, the utilization efficiency of the noble co-catalysts is still very low on a per metal atom basis if no obvious size effect exists, because heterogeneous catalytic reactions occur on the surface active atoms. Here, for the first time, we have synthesized isolated metal atoms (Pt, Pd, Rh, or Ru) stably by anchoring on TiO2, a model photocatalystic system, by a facile one-step method. The isolated metal atom based photocatalysts show excellent stability for H-2 evolution and can lead to a 6-13-fold increase in photocatalytic activity over the metal clusters loaded on TiO2 by the traditional method. Furthermore, the configurations of isolated atoms as well as the originality of their unusual stability were analyzed by a collaborative work from both experiments and theoretical calculations.

A nitrile-metabolising enzyme and a process for producing an acid using same

The present invention relates to an isolated nucleotide sequence and corresponding polypeptide derived from the nitrile-metabolising Pantoea strain deposited under NCIMB 41854. Said isolated polypeptide acts as a nitrilase and the invention extends to a process for producing a carboxylic acid using said isolated polypeptide to metabolise nitriles such as 3-hydroxyglutaronitrile, 3-hydroxybutyronitrile and 3- hydroxy-phenylpropionitrile to form corresponding carboxylic acids.

Intergenerational transmission of conflict-related trauma in Northern Ireland: A behaviour analytic approach

Intergenerational transmission of trauma describes the impact that traumatic events experienced by one generation have for the subsequent generation. In Northern Ireland, violent conflict raged between 1969 and 1998, when a peace process begun. This study explored to what extent (if any) parents’ experiences of the conflict influenced how children perceived life in this society. Parents completed a questionnaire, and their children drew 2 pictures, depicting Northern Ireland now and before they were born. Children’s behaviors and awareness of the conflict were influenced by their parents’ experiences and narratives, their age, gender, and school. Parental narrative about the violence was influenced by individual learning history, the child’s age and gender, and present circumstances. A behavior analytic approach is offered.

Diversity and characterisation of coagulasenegative staphylococci isolated from healthy individuals in Portugal

In the past few years the interest in coagulase-negative staphylococci (CoNS) has significantly increased in human medicine. CoNS are common commensal colonisers of the human skin, although now also recognised as major nosocomial pathogens. Over the last decades, several studies have been carried out in order to understand the pathogenicity mechanisms of CoNS. The well known determinants in the pathogenesis of CoNS infections are their ability to form biofilms and an exceptional resistance to several antibiotics. Nevertheless, there is a lack of studies regarding the commensal lifestyle of these microorganisms. Additionally, it is now hypothesised that commensal bacteria might be a reservoir of pathogenic determinants. Therefore, the work described throughout this thesis was aimed to perform a phenotypic and genotypic characterisation of different CoNS species isolated from healthy Portuguese individuals. A total of 61 CoNS isolates, comprising 7 different species, were obtained and characterised at the level of biofilm formation and antibiotic susceptibility profiles. According to the results, biofilm formation ability and presence of biofilm-associated genes were commonly found features, highlighting their pivotal role in the colonising lifestyle of CoNS. This study also addressed the correlation between phenotypic and genotypic characteristics of biofilm formation, corroborating and raising questions about the importance of some genes in this process. Moreover, it was observed a great proportion of isolates with decreased susceptibility and multiple resistances to some important antibiotics. A significant association between antibiotic resistance and biofilm formation was also demonstrated, and some hypotheses about the nature of such association were provided. Lastly, the expression patterns of two biofilm-associated genes at two distinct biofilm developmental stages were determined, confirming their importance in the accumulative stage of biofilm formation. Overall, the results presented in this thesis indicate that staphylococcal skin flora might be an important reservoir of potentially pathogenic bacteria and, simultaneously, bring to light new perceptions about the molecular basis of staphylococcal biofilm formation, and the nature of the association between antibiotic resistance and biofilm formation.

Influência de um programa de exercícios específicos em estudantes de violino

Introdução: A elevada prevalência de problemas musculosqueléticos relacionados com a performance musical (PMRPM) em estudantes universitários de música, sobretudo violinistas, justifica uma abordagem preventiva junto destes, nomeadamente, através do exercício. Este deve ser específico e baseado nos padrões de movimento durante a performance musical do violinista. Objetivos: verificar a influência de um programa de exercícios específicos (PEE) nos sintomas relacionados com a prática musical, na incapacidade funcional e na autoperceção da performance física e musical, em estudantes universitários de violino. Métodos: estudo quase-experimental baseado num estudo piloto com 24 estudantes para pesquisa da sintomatologia, e 4 para análise cinemática e cinética do gesto técnico. No estudo principal participaram 22 violinistas divididos equitativamente, e por disponibilidade, entre grupo experimental (GE) e grupo de controlo (GC). O GE realizou o PEE bissemanalmente, durante 8 semanas. No momento inicial e após 8 semanas, os participantes preencheram: Questionário de Performance (incluiu Escala Visual Analógica), Disabilities of the Arm, Shoulder and Hand, Oswestry Disability Index versão 2.0, Pain Catastrophizing Scale e Escala de Borg Modificada. Resultados: do estudo piloto constatou-se que os sintomas mais frequentes, dor e fadiga, localizavam-se na cintura escapular, ombros e coluna lombar; os ombros aparentavam maior risco de PMRPM; era necessário aumentar a endurance dos mobilizadores dos membros superiores (principalmente deltóide) e relaxar os estabilizadores da coluna cervical (sobretudo trapézio superior). No final do PEE, o GE apresentou significativamente melhores pontuações do que o GC na percentagem de violinistas com “dor na coluna lombar esquerda” (p=0,007), frequência da dor (U=8,5; W=29,5; p=0,016), número de locais com sintomas (U=18; W=84; p=0,003) e amplificação (U=26; W=92; p=0,021). Conclusão: Um PEE pode produzir efeitos positivos na diminuição dos sintomas relacionados com a prática musical e incapacidade funcional, e na melhoria de alguns parâmetros da performance física autoreportada, em estudantes universitários de violino.

The Na+-dependent chloride-bicarbonate exchanger SLC4A8 mediates an electroneutral Na+ reabsorption process in the renal cortical collecting ducts of mice.

Regulation of sodium balance is a critical factor in the maintenance of euvolemia, and dysregulation of renal sodium excretion results in disorders of altered intravascular volume, such as hypertension. The amiloride-sensitive epithelial sodium channel (ENaC) is thought to be the only mechanism for sodium transport in the cortical collecting duct (CCD) of the kidney. However, it has been found that much of the sodium absorption in the CCD is actually amiloride insensitive and sensitive to thiazide diuretics, which also block the Na-Cl cotransporter (NCC) located in the distal convoluted tubule. In this study, we have demonstrated the presence of electroneutral, amiloride-resistant, thiazide-sensitive, transepithelial NaCl absorption in mouse CCDs, which persists even with genetic disruption of ENaC. Furthermore, hydrochlorothiazide (HCTZ) increased excretion of Na+ and Cl- in mice devoid of the thiazide target NCC, suggesting that an additional mechanism might account for this effect. Studies on isolated CCDs suggested that the parallel action of the Na+-driven Cl-/HCO3- exchanger (NDCBE/SLC4A8) and the Na+-independent Cl-/HCO3- exchanger (pendrin/SLC26A4) accounted for the electroneutral thiazide-sensitive sodium transport. Furthermore, genetic ablation of SLC4A8 abolished thiazide-sensitive NaCl transport in the CCD. These studies establish what we believe to be a novel role for NDCBE in mediating substantial Na+ reabsorption in the CCD and suggest a role for this transporter in the regulation of fluid homeostasis in mice.

In vitro functionality of isolated embryonic hypothalamic vasopressinergic and oxytocinergic neurons: modulatory effects of brain-derived neurotrophic factor and angiotensin II.

There are only a few studies on the ontogeny and differentiation process of the hypothalamic supraoptic-paraventriculo-neurohypophysial neurosecretory system. In vitro neuron survival improves if cells are of embryonic origin; however, surviving hypothalamic neurons in culture were found to express small and minimal amounts of arginine-vasopressin (AVP) and oxytocin (OT), respectively. The aim of this study was to develop a primary neuronal culture design applicable to the study of magnocellular hypothalamic system functionality. For this purpose, a primary neuronal culture was set up after mechanical dissociation of sterile hypothalamic blocks from 17-day-old Sprague-Dawley rat embryos (E17) of both sexes. Isolated hypothalamic cells were cultured with supplemented (B27)-NeuroBasal medium containing an agent inhibiting non-neuron cell proliferation. The neurosecretory process was characterized by detecting AVP and OT secreted into the medium on different days of culture. Data indicate that spontaneous AVP and OT release occurred in a culture day-dependent fashion, being maximal on day 13 for AVP, and on day 10 for OT. Interestingly, brain-derived neurotrophic factor (BDNF) and Angiotensin II (A II) were able to positively modulate neuropeptide output. Furthermore, on day 17 of culture, non-specific (high-KCl) and specific (Angiotensin II) stimuli were able to significantly (P < 0.05) enhance the secretion of both neuropeptides over respective baselines. This study suggests that our experimental design is useful for the study of AVP- and OT-ergic neuron functionality and that BDNF and A II are positive modulators of embryonic hypothalamic cell development.

Electrogenic proton/L-glutamate symport in isolated asparagus sprengeri mesophyll cell

Medium' alkaliniiation occurred -lipon the addition of L-Glu to mechanically isolated Asparagus sprenger-i mesophyll cells suspended in 1 mM CaS04. Alkalinization resulted from the coupled entry of H+ and L-Glu anion into the cells. This H+ IL-Glu symport did not stimulate K+ efflux. K+ efflux has been observed during H~ lamino acid symport in other systems. The stimulation of K+ efflux by proton coupled symport is regarded as an indicator of a plasma membrane depolarizing electrogenic symport process. H+ IL-Glu symport in Asparagus sprengerimesophyl1 cells was investigated to determine whether or not the process was electrogenic. The rate of uptake of 0.25 11M 3H-MTPP+ ( Methyltriphenylphosphonium, methyl-3H ) is a probe for monitoring changes in the membrane potential. 3HMTPP+ uptake was reduced by K+ or CCCP, agents known to depolarize the membrane potential. Uptake of 3H-MTPP+ was also inhibited by L-Glu but not by D-Glu. Conversely, 10 mM external MTPP+ inhibited the uptake of 14C-U-LGlu. Simultaneous measurements of the rates of 14C-U-L-Glu uptake and L-Glu dependent H+ influx showed that the molar stoichiometry of H+ IL-Glu symport was 2 to 1. K+ or Na+ stimulated H+ efflux was completely inhibited by DCCD, DES, oligomycin and antimycin reagents which inhibit ATP driven H+ efflux. The H+ efflux \Vas also stimulate.d by the weak acids, butyric acid and acetic acid, which are known fo-aCidify the cytoplasm. This weak acid stimulated H+ efflux was also completely inhibited by oligomycin. It was calculated that net L-Glu dependent H+ influx increased by 100% in the presence of oligomycin and that despite net medium alkalinization H+ IL-Glu symport stimulates ATP dependent H+ efflux. 11 The data presented in this study indicate that H+ IL-Glu symport is electrogenic. The data also show that ATP dependent Ht efflux rather than K+ efflux is the- process compensating for thi~ electrogenic H+ IL-Glu symport.

L-Glutamate uptake, decarboxylation to -aminobutyric acid and GABA efflux in isolated Asparagus sprengeri mesophyll cells

Addition of L-glutamate caused alkalinization of the medium surrounding Asparagus spreng.ri mesophyll cells. This suggests a H+/L-glutmate symport uptake system for L-glutamate. However stoichiometries of H+/L-glutamate symport into Asparagus cells were much higher than those in other plant systems. Medium alkalinization may also result from a metabolic decarboxylation process. Since L-glutmate is decarboxylated to r-amino butyric acid (SABA) in this system, the origin of medium alkalinization was reconsidered. Suspensions of mechanically isolated and photosyntheically competent Asparagus sprengeri mesophyll cells were used to investigate the H+/L-glutamate symport system, SABA production, GABA transport, and the origin of L-glutamate dependent medium alkalinization. The major results obtained are summarized as follows: 1. L-Glutamate and GABA were the second or third most abundant amino acids in these cells. Cellular concentrations of L-glutamate were 1.09 mM and 1.31 mM in the light and dark, respectively. Those of SABA were 1.23 mM and 1.17 mM in the light and dark, respectively. 2. Asparagine was the most abundant amino acid in xylem sap and comprised 54 to 68 1. of the amino acid pool on a molar basis. GABA was the second most abundant amino acid and represented 10 to 11 1. of the amino acid pool. L-Slutamate was a minor component. 3. A 10 minute incubation with 1 mM L-glutamate increased the production of GABA in the medium by 2,743 7. and 2,241 7. in the light and dark, respectively. 4. L-Glutamate entered the cells prior to decarboxylation. 5. There was no evidence for a H+/GABA symport process • 6. GABA was produced by loss of carbon-1 of L-glutamate. 7. The specific activity of newly synthesized labeled GABA suggests that it is not equilibrated with a storage pool of GABA. 8. The mechanism of GABA efflux appears to be a passive process. 9. The evidence indicates that the origin of L-glutamate dependent medium alkalinization is a H+/L-glutamate symport not an extracellular decarboxylation. The possible role of GABA production in regulating cytoplasmic pH and L-glutamate levels during rapid electrogenic H+/L-glutamate symport is discussed.

The encounter with the real and post-Soviet trauma : fantasy construction in Russian popular cinema /

This thesis examines the impact of the Soviet Union's collapse on the Russian Symbolic as represented through popular cinema of the post-Soviet period. The disintegration of the USSR in 1991 became one of the most traumatic experiences for many Russian people. The trauma of the collapse of the Soviet Union penetrated the everyday reality of the Russian Symbolic, leaving the traces-symptoms in different cultural fonns like literature, arts, television and cinema. Because popular culture usually reacts very quickly to any social, political and economical shifts in society, it is an excellent barometer for deeper changes in society. Focusing on postSoviet popular cinema, this thesis analyzes the symptoms of cultural and individual trauma occasioned by the momentous changes of the 1990's. This study is grounded in post-analytic theory of Jacques Lacan and its interpretation by Slavoj Zizek, which emphases the traumatic encounter with the Real as a "hard core" of our reality. According to this paradigm, a new chain of signifiers is structured around the traumatic breach in the Symbolic, initiating a process of fantasy construction to deal with consequences of trauma and, thus, to support our Symbolic order. This thesis examines three major fantasy constructions - drinking, traveling to a "happy land" and family reunion and money - in popular films by Alexander Rogozhkin, Yurij Mamin, Georgij Shengelia, Dmitrij Astrakhan, Valerij Todorovskij, Alexej Balabanov, Sergej Bodrov Jr. and Petr Buslov. According to Zizek, enjoyment underlies any fantasy constructions, and that is why after the intrusion of the Real every individual and culture should go through the process of fantasizing about some substitutes which can help to minimize the traumatic effect and which can lead to a partial enjoyment. By analyzing the fantasies about drinking, "happy land", reconstruction of the family bonds and money in Russian popular cinema since 1991, this thesis demonstrates how the traumatic engagement with the Real affected the everyday lives of Russian people, and how individuals tried to fill the gap, the lack, in the post-Soviet Symbolic and "return" the lost feeling of unity and plenitude.