Graphene: Development and Applications

Graphene: Development and Applications Number of carbon atoms packed in a two-dimensional (2D) grid cells as flat single layer give the graphene. This is a key building block for graphitic materials of all sizes. It can be enclosed in fullerenes (0D), rolled into 1D nanotubes or stacked into three dimensional graphite. A serious step forward in the study of graphene was when Andre Geim and Kostya Novoselov from Manchester extracted Singlet thick crystallites (graphene) from crude graphite in 2004. The unique electronic properties of graphene produce an unexpectedly high opacity for one atomic monolayer, with amazingly simple value : it absorbs ~ 2.3 % of white light . This is a consequence of the unusually low energy electronic structure of monolayer graphene saws which electrons and holes tapered zone which meet each other at the point Dirac which is qualitatively different from the more common solid square zones. In 2008 carried out the first experiment proves that graphene is the strongest material that exists in nature. The measurements showed that graphene has a tensile strength of 100 times greater than steel. Graphene is different from most conventional 3D materials. The natural Graphene presents a semimetal or zero-gap semiconductor. Been a long time since we talked through the Medgreece in graphene and its unique properties. Graphene is a material which was discovered relatively recently, and its main feature is that it is a graphite sheet consisting of a lattice of carbon atoms linked together as shown in the photo of the article ( we could characterize as a wire ) which has a thickness of a single atom . So far it has been described as the ideal replacement for silicon , and has a very low resistance and higher conductivity which can lead to the creation of faster chips for computers . And all at room temperature . Where else could however be used graphene ? From the University of California , and Alexander Balandin (Chair of Materials Science and Engineering), investigated the possibility of using graphene sheets as heat conductors . The researchers call these cards quilts ( like a quilt ) and that is because the graphene sheets are not homogeneous but consist of flakes graphene , which overlap creating a spreadsheet. Only unlike the quilt ( we all know ) the quilt of graphene flakes will not retain heat, but will remove it . The graphene sheets can be used to extract heat from parts of a circuit which, due to the high speed flow of electrons ( current) particularly heated , which leads to impaired function of the circuit. Helping the diffusion of that heat , graphene will help create sdti much faster chip . Graphene based on measurements made à ¢Ã¢â€š ¬Ã¢â‚¬ ¹Ãƒ ¢Ã¢â€š ¬Ã¢â‚¬ ¹by the researchers shows remarkably high thermal conductivity that surpasses even that of diamond and carbon nanotubes. The properties of graphene , (electrical conductivity , low resistance , high thermal conductivity ) find no scope only chip electronic circuits. As we mentioned previously this technology could even be used to improve the photovoltaic , since one of the main problems (in terms of performance ) is the high resistance of the conductor carrying the current. Graphene thanks to its properties , could significantly increase their performance Chapter 1: Carbon Nanostructures 1.1 A new class of materials The two-dimensional (2D) crystalline materials have only recently been identified and investigated. [1] The first material that falls into this category, is graphene, a singlet carbon layer. This new material has unique properties that make it extremely interesting both as basic knowledge, as well as for future applications. The electronic properties of graphene, for example, have resulted in an unusual quantum Hall [2], [3]. It is a transparent conductor [4] with a thickness equal to the extent of zp orbital of an atom of carbon (0,344 nm). It also has parallels with the physics of elementary particles which for example displays an unusual tunneling [5], [6], which was predicted by the Swedish Natural Oscar Klein [7]. Additionally, graphene exhibits excellent mechanical and electrical properties. Its mechanical strength is greater than steel while it can be bent. The thermal and electrical conductivity is very high and can be used as a flexible conduit. The Andre K. Geim and Kostant in S. Novoselov from the University of Manchester, were awarded the 2010 Nobel Prize for the production, isolation and identification of graphene [1]. 1.2 Forms of carbon Carbon is perhaps the most exciting element of the periodic table. It is the basis of DNA and life on earth. O coal occurs in different forms. The most common form of carbon, graphite, which consists of stacked sheet carbonates hexagonal structure. At high pressures, the diamond is created, which is a metastable form of carbon. A relatively new form of molecular carbon, are the Fullerenes (Fullerenes) [8]. The most ordinary fullerene consists of 60 carbon atoms (60 C) and has the shape of a football. It is consisting of 20 hexagons and 12 pentagons which enable the surface to form a ball. The discovery of fullerenes was awarded the Nobel Prize in Chemistry in 1996. The existence of a pseudo-one-dimensional form of carbon, carbon nanotubes, has been known for many decades and the existence of single-wall carbon nanotubes in 1993 [9]. The nanotubes are formed by winding of a graphene sheet so as to acquire a cylindrical shape with hemispherical ends with a configuration similar to that of the fullerene. The electronic and mechanical properties of metallic nanotubes, show many similarities with those of graphene. It was already known that the toner is composed of hexagonal carbon levels which are stacked on top of one another but scientists believed that such a singlet carbonate sheet could not be produced. In 2004, however, scientists A. Geim, K. Novoselov and colleagues [1] showed that such an individual could be isolated and was stable. The singlet this level carbon called graphene. Figure 1.1. The graphene sheets form the native structure of the graphite, carbon nanotubes and fullerenes [11]. It should be noted that structures similar to graphene has been known since the 1960s [10] but there were experimental difficulties in isolating them and raises doubts about whether this would be possible. The amazing thing is that a simple pencil contains graphite and as it moves the paper, toner levels separated in a very small part of which contains some of singlet layers of graphite, ie graphene. The difficulty is not the production of graphene structures but rather to isolate large quantities of singlet levels for the identification, characterization and study its properties. This just managed to make the Geim and Novoselov. 1.3 Graphene Graphene is called a singlet level of carbon atoms arranged in a hexagonal lattice, with nearest neighbor distance of atoms 0.142 nm. It is the first truly two-dimensional crystalline material and is representative of a whole class of two-dimensional materials which includes for example Psychosocial Critical Evaluation: Case Study of Rory Psychosocial Critical Evaluation: Case Study of Rory Psychosocial Critical Evaluation: Case Study of Rory Introduction Psychosocial theory originates from psychoanalytic and psychodynamic casework, which has had a profound and lasting impact on social work (Kenny and Kenny, 2000). This assignment will use the case study of Rory, a fifteen year old boy living in a family home with his brother, mother and stepmother. Throughout the assignment Rory’s social environment and his relationships within this environment will be analysed in order to understand how these factors have shaped his development. Following on from this an evaluation of group work as an intervention method to support and empower Rory shall be explored. Group work will be taken as evidence for practice, where social work practice is carried out in groups (Doel, 2000, p.148). Psychosocial theories will be explored into how they influence group work and group dynamics, and the way group work can be used to change and adjust dysfunctional social environments. In doing so, the model of psychosocial theory and its relevance to social work will be explored, and how useful it is in understanding clients and promoting their best interests. In order to critique the model of psychosocial theory, and explore how it influences our perception of the human condition, we must have a clear idea of what we mean by the term. Modern social work theorists have stressed the importance of applying the correct competency to the individual person, with regard to their social environment (Hutchinson, 2008). It sees people as ‘products of the interaction among their biogenetic endowment, the effects of significant relationships, the impact of life experiences, and their participation in societal, cultural and current events’ (Turner, 1978, p.2). The social work profession, can see the individual person as interdependent with their environment, which they are able to influence and change (Kondrat, 2002). By seeing individuals as being uniquely shaped by their environment, it helps social workers avoid the issues of social identity theory. Rather than categorising or stereotyping people, social workers are able to empathise a nd see all service users as individuals (Tajfel and Turner, 1979, cited in Gaine, 2010). The main ideas of psychosocial theory are reflected in other social work theories and methods, such as systems and attachment theory. Both theories developed from the need to build upon the traditional psychoanalytic model of individual therapy (Walker, 2012), and the idea that individual experiences with families were continually being shaped and influenced by the evolving interaction patterns of communication. For group work to be beneficial there must be a mindfulness of the social context or sociology of the individual and group. Understanding individuals who compromise the group requires knowledge of ‘psychosocial functioning and development through the life cycle’ but also the impact of the group’s structure and process on the members’ behaviour. A group cannot be understood without knowledge of members in their individual social context (Northern and Kurland, 2001, p.35). This promotes and encourages diversity within the group, as practitioners are mindful of differences within the group, and how they can be addressed to promote social skills such as empathy and respect. If a client’s environment and social context has been dysfunctional, as in Rory’s case, the group work can provide a model of a healthy culture through the group values, communication patterns, and the way it addresses interpersonal conflict (Northern and Kurland, 2001). Having explored the connection between group work and psychosocial theory, two theories of social work shall be applied and explored next. Attachment theory focuses on the quality of the attachments in the significant relationships in a client’s past (Bowlby, 1979, 1988). Bowlby’s theory of attachment stresses the importance of past relationships by determining which will develop emotionally and socially, and form relationships in the future. Bowlby was particularly concerned with the interactions and attachments that individuals had with their parents or carers. The ability of a child to attach to a parent or carer, the level of consistency of the parent or carer to meet the emotional needs of a child and the ability of the child to feel safe and secure, predicted how the child would develop emotionally. This theory has particular relevance and importance for this case study. The relationship between Rory and his mother can be recognised as a disorganised attachment. H is mother’s bi-polar disorder means her behaviour is inconsistent at times, due to her having stable periods but when her mood is very bleak she neglects the needs of Rory and his brother. From this behaviour Rory receives mixed messages, leaving him feeling anxious and unable to explain and possibly understand his own feelings (Bowlby, 1988). His father appears to display as insecure or ambivalent attachment, this is due to him demonstrating an inconsistency in his attitude to Rory, neglecting contact for several weeks at a time. His unpredictable behaviour and failure to display attention in a consistent way leads to anxiety and distress for Rory. Attachment theory is helpful to social workers in planning intervention, as they have insight into how past experiences of the service user can impact on their behaviour, and their ability to form relationships. For example, at the Youth Club Rory is seen as increasingly withdrawn and erratic by the youth workers. This may be due to his disorganised attachments impacting upon his ability to behave in social situations. Preston-Shoot and Agass (1990) explains that the development and quality of relationships can be influenced by considering the impact of the client’s feelings on behaviours. Group work can be a powerful tool when based on attachment theory issues. Egeland and Erikson (1993) and Eriskon et al., (1992) described a group in which young, high-risk mothers were brought together for weekly group sessions from the time their children were born until they were one year old. Group work was effective here for two reasons. Firstly, through the therapeutic relationship itself, or the relationship with the group facilitator, in which ‘the facilitator maintains a healthy, supportive alliance with the parent, proving such relationships are possible’ (Erikson et al., 1992, p.501). When using any intervention, it is important to create a working alliance, in which the patient has confidence that the practitioner can help (Holmes, 2001). Due to Rory having all his immediate adult relationships in his life being inconsistent and causing him anxiety, having another which proves to be consistent in his life, one that is dependable, may improve his self-esteem an d address problems he is exhibiting in social situations, such as at the Youth Club. The reason he may be attending the Youth Club could be due to him searching for that consistency and dependable person he needs, as the Youth Club is a weekly activity which is always there. The ‘therapeutic’ relationship gives Rory a ‘secure base’ (Holmes, 2001, p.17) where the task can challenge assumptions and relationship patterns. Group work would also introduce Rory to a plethora of perspectives and individuals. Through this, Rory may become conscious of thoughts and attitudes that were previously unconscious (Holmes, 2001). In listening to and working with others Rory may build up his self-esteem. As he begins to form relationships with members of the group, he has models of healthy and functional relationships that are different from his own attachments with family members. This could increase his confidence, addressing problems of withdrawn and erratic behaviour that have been raised by Youth Workers at Youth Club. A number of studies have shown group work can improve social skills (Reid and Hammond, 2001; Fargan and Jones, 2002). Group work also promotes diversity as those it helps do not feel isolated or alienated by their problems: through sharing experiences in a respectful and tolerant environment they gain insight into the sufferings and challenges of others, and methods to overcome this. Groupwork a s a form of learning extends beyond this, as groups offer members feedback that is often more effective coming from peers than from a social worker (Northern and Kurland, 2001). When done sensitively and constructively, such feedback helps clients such as Rory with their social skills and their ability to build relationships outside of the group. A weakness of this theory, however, may that does it is not sufficiently encompassing of all the social forces that act on the individual. Psychosocial theory holds that we should acknowledge the role in human development of temperament, racism, poverty, social class, and other environmental conditions (criticism outlined in Coady and Lehman, 2007). Group dynamics and interactions cannot be understood through individual’s relationships with their parents alone. Psychosocial theory assists social workers in understanding and analysing the situations and behaviours of their client. This provides practitioners with insight into what has occurred in the past or what may occur in the future. However, some argue that attachment theory does not paint a picture of the client whole: by attributing all of Rory’s behaviours and concerns to his parents, the practitioner may neglect the wider social context that is acting on him. Systems theory may offer a more encompassing picture of Rory’s social context. This theory holds that individuals and their environments are separate systems that are interconnected and interdependent (Teater, 2010). By thinking of families as living systems, systems theories are able to think about how dynamics are constantly altering as each family member deals with life inside and outside the family. Rory’s withdrawn behaviour, and self-destructive thoughts can be attributed to the frequency with which his family dynamics change. This change is at times dramatic for example the breakdown of his parent’s relationship, or his sister leaving the family home- but also in the inconsistencies due to his stepfather’s temper and mother’s mental illness. Systems theory also promotes tolerance and diversity, as it recognises that there is no one model for a healthy, functioning family (Walker, 2012). A change or movement in one of these systems results in change or movement in the others. In Rory’s case, social systems theory is useful as it allows social workers to identify which system requires an intervention (Teater, 2010). The key question is ‘does this structure work for this family’ and does it allow for the healthy development and growth of family members? As such, the Munro Report confirms that a systems perspective offers the most holistic tool for undertaking informed assessment work that takes into full account the wide environmental factors combined with the inter-personal relationship patterns that influence family experiences (cited in Walker, 2012). Furthermore, a family’s structure and organisation allows social workers to determine, to some extent what is possible within a particular family. Thinking of families systematically also ensures no family member is marginalised (Walker, 2012). One-to-one intervention with Rory will have an i mpact on the whole family system; his mother, brother and stepfather will be affected, and also the family dynamic as a whole. As such, group work is an effective method of intervention according to social systems theory. This is because it avoids the risk that the family’s problems and their solutions are individualised. By placing Rory in a different group dynamic, one that has been constructed by a facilitator or practitioner, social workers may be able to assess which elements of the family’s structure need intervention, and where Rory and the family need extra support. By assessing Rory’s patterns of communication and interaction outside his family dynamic, practitioners may gain greater insight into his specific needs and methods that can be used to support and empower him. Groupwork for families links closely to the family therapy movement (pioneered by figures such as Murray Bowen, Jay Haley, and Virginia Satir). The family therapy movement advocates systemic features as a means by which to assess the way groups of relatives organise themselves over time, creating stable patterns, that are inclined to return to familiar states. As such, one of the beliefs is that systems tend to be self-correcting, based on positive or negative feedback (Coady and Lehmen, 2007). By using groupwork intervention with Rory, he may feel empowered and supported to address and correct the patterns and familiar states of his family, rather than simply removing himself from situations. Furthermore, the counsellor or practitioner can address the dysfunctional and destructive subsystems that exist within Rory’s family. A concern surrounding this theory of social work, however, is the emphasis social systems theory places on adaptation. The purpose of the group work intervention is to explore how systems can be adjusted and change to create a healthy and supportive structure. As such, some fear that practitioners are encouraging clients to accommodate to oppressive circumstances (Coady and Lehmen, 2007). From this perspective, Rory may be being taught to accept and adapt to the hostile and threatening behaviour of his stepfather, or the neglect he sometimes faces from his mother. This can be addressed by being mindful of social work’s traditional concern with social justice- an integration of values such as social justice and social systems based thinking is possible. To do this, practitioners must be self-reflective and question their own values and assumptions, particularly in terms of prejudice and diversity, in order to ensure that the client’s best interests are at the heart of gr oup work intervention. An awareness of social circumstance is also important in tackling diversity with regard to mental health. Parental mental health, and the disruption to parenting capacity has been found to have profound and persistent implications for children and their parents (Smith, 2004). As such, it has been advocated that social workers have improved access to training that assists with psychosocial interventions, such as group work (National Institute for Mental Health in England, 2005). This helps us to understand the quality of attachment between Rory and his mother. Rory himself is displaying behaviours that may point to mental health, particularly disclosing suicidal thoughts. Research shows that social work plays a significant role of social work in promoting the involvement of people using services and developing systemic approaches to practice with families (Gilbert, 2007). Diversity is important here- social workers must address societal stigmas regarding mental health. Effective inter vention can also promote diversity by helping those with mental health to function and become involved in society. A psychosocial approach helps us to understand Rory’s patterns of communication and behaviour, as it gives us insight into the formative relationships, experiences and environments that have categorised his life thus far. This puts troubling behaviours, such as self-destructive and suicidal thoughts, within a social context that can be used as the basis for assessment and intervention. Our chosen intervention method, group work, is also revealing about how Rory can be supported and empowered. By modelling healthy and secure relationships, and developing Rory’s social skills, Rory’s future relationships do not have to be influenced solely by dysfunctional attachments with his parents and stepfather. By understanding his family as a system, and observing Rory but within that system and in other groups, insight is gained into how Rory’s social context can be adapted in order to promote the healthy growth of all its members.