Informative and surprising paper about America problem Immigration Essay

Informative and surprising paper about America problem Immigration - Essay Example   This roughly suggests that one person from each 35 is moving to some other nation regarding professional or any other reasons. (Mchedlishvili) The discourse of immigration comprises of several issues, such as professional immigration, reunification of families etc.   The big nations such as United States of America- faces the immigration matter probably more than any other land.   This paper aims to reflect on whether immigration is a good or a bad thing for a nation, in both ways, for the nation that is producing these migrants and also for the nation who is sustaining them into it. First the discussion is focused upon general view and then it presents my surprising view on the subject. I differ with the common people especially belonging to developing nations on their idea that America is a land of opportunities. Being a student in a reputed university I find several students getting admitted here every year. Most of them are from Asian countries like Pakistan, India and China. They come here mainly because they think the country to be full of opportunities for them, both in terms of education and work. It feels good to hear that they have such intense faith in the economy of the nation. Immigration in America not only occurs from the mentioned nations, but a large number of people travel to America from third world nations. I have often discussed about this immigration issue with many people, some of them are my friends. Mostly my professors help me in knowing more in this regard.   I came to know that, the largest part of this immigration occurs due to the employment problems.  Lately the open trade and investment atmosphere has led to a huge exodus from different countries to America.   Initially a vast and higher demand of labors in the industrial countries such as America and the huge number of unemployed labors in the undeveloped or the developing nations has set the wheels of immigration in great motion.   This has been a part of the hiring

Aircraft Carrier Research Paper Example | Topics and Well Written Essays - 1500 words

Aircraft Carrier - Research Paper Example This essay stresses that the navy uses the aircraft carriers in the sea, and this allows military aircrafts to land and take off on the flat decks of the warships. The decks store aircrafts, which are brought up using elevators. Aircrafts land safely, with the use of arresting cables, which have a hook attached on the aircraft. Aircraft carriers are accompanied by vessels such as destroyers, and they carry weapons of war such as missiles. They provide cover to other warships and can perform operations in waters outside the borders of a country freely. This paper makes a conclusion that aircraft carriers have advanced self-close defense system, designed to detect any possible external threats and attacks on the ship. The carriers have automated sensors and weapons that can be used fro combat during an attack from enemies. The self-close defenses system coordinates and identifies potential threat and executes necessary procedures during times of attack. Thus, the aircraft may not become obsolete owing to the defense system that allows for the detection and prevention of threat. The strategic significance of aircraft carriers may make them not to become obsolete in times of war. Advancements in the warships have made it strategic during times of war, as modern navies use it to project their powers. Flights have become a vital asset and machine during the war. Based on this, ships powered by nuclear powers that carry fighter jets and planes have been widely used during times of war. ... Several reasons explain why the carrier may not be obsolete. They have advanced Self-close defense system Aircraft carriers have advanced self-close defense system, designed to detect any possible external threats and attacks on the ship. The carriers have automated sensors and weapons that can be used fro combat during an attack from enemies. The self-close defenses system coordinates and identifies potential threat and executes necessary procedures during times of attack. Thus, the aircraft may not become obsolete owing to the defense system that allows for the detection and prevention of threat (Ireland, 2008). They are still a major investment for many countries According to Fontenoy (2006), many countries still carry out investments in the aircraft carriers, with budgetary allocations including in them a component of the warship. Since the carriers have been used for many years, most nations all over the world have come to trust the carriers. Therefore, many countries still inve st in them, because they have proven useful during war. The investment in these warships serves as an indication that they may not necessarily become obsolete. Investments in the warship may take place for including the future. The strategic significance is obvious and irreplaceable The strategic significance of aircraft carriers may make them not to become obsolete in times of war. Advancements in the warships have made it strategic during times of war, as modern navies use it to project their powers (Fontenoy, 2006). Flights have become a vital asset and machine during the war. Based on this, ships powered by nuclear powers that carry fighter jets and planes have been widely used during times of war. The carriers have the capability to carry many aircrafts; therefore, they have been

The Drama Of The Love Triangle In Literature Essay - 1

The Drama Of The Love Triangle In Literature - Essay Example The door goes unanswered after they rang the doorbell for several times, but as they were about to leave, they heard footsteps from the inside of the house. The door opened and there stood Liz wearing her chequered black and white pajama and a cheeky smile, which was so unusual for her. After exchanging pleasantries, they entered the house, and this time Kelvin’s attempt to hold Linda’s hand was not rejected. They walked hand in hand up to the living room and from the look on Liz’s face, the gesture was not welcome. Kelvin having known Liz for a long time let off Linda’s hand. Liz rushed to the kitchen to fetch a drink for them and Kelvin could not help staring at the rich bosom that Liz displayed when she was rising from her seat to go to the kitchen. When he realized he was being watched, he tried to look the other way, but Linda had already noticed and she mumbled something that was not coherent. Liz returned with a bottle of grape juice, which they proceeded to take as they chatted over general things. When it was time to leave, Kelvin explained to Liz their reason for coming and signaled Linda to give Liz the story as she had narrated to him before they left college premises earlier in the day. Linda gave her side of the story as she had given it to Kelvin, although this time she seemed more emotional, which at one point moved Liz to tears. Kelvin, who was used to seeing women cry, started to get irritated when he saw the discussion was getting emotional, so he excused himself to the washroom. After leaving, the two women looked at each other with te ary eyes, and a sense of connection between them attracted them to each other; however, to Linda there was something about Liz that made her suspicious, but since her newfound friend Kelvin had told her that she is a God fearing person, she had no reason to worry.

The Impact of Motivation on English Language Learning Research Paper

The Impact of Motivation on English Language Learning - Research Paper Example Although it is widely documented that motivation is a proven means to success in language learning, several countries, like the Gulf States, remain reluctant to cultivate learners’ motivation to learn a second language due to several reasons. Therefore, this research paper analyses the impact of motivation on English language learning. Introduction Motivation has been broadly recognised by scholars, researchers, and teachers as one of the major variables that determine the level and success of second language learning (SLA). As emphasised by Dornyei (2001), â€Å"teacher skills in motivating learners should be seen as central to teaching effectiveness† (P. 116). Motivated learners are enthusiastic, eager to work hard, concentrate on the tasks given, do not require constant encouragement, willingly confront challenges, and could even motivates others, facilitating collaborative learning. The early attempt to understand the impact of motivation on English language learnin g stems from the field of social psychology (Gu, 2009). This research paper analyses the impact of motivation on English language learning in terms of the various motivational theories. The motivation of learners greatly affects their willingness to take part in the process of learning. Numerous studies have reported the importance of viewing the concept of motivation as a multifaceted phenomenon. Oxford and Shearin (1994) have examined a number of motivational theories and six variables that influence motivation in language learning (Al-Bustan & Al-Bustan, 2009, S454): Attitudes (i.e. sentiments towards the target language). Beliefs about self (i.e. expectations about one’s attitudes to succeed, self-efficiency, and anxiety). Goals (perceived clarity and relevance of learning goals as reasons for learning). Involvement (i.e. extent to which the learner actively and consciously participates in the learning process). Environmental support (i.e. extent of teacher and peer suppo rt). Personnel attributes (i.e. aptitude, and language learning experience). As argued by Pit Corder, â€Å"given motivation, it is inevitable that a human being will learn a second language if he is exposed to the language data† (Dornyei & Ushioda, 2009, 1). This statement was given four decades ago and, from then on, numerous theroetical perspectives and studies investigating the multifaceted nature of motivation and its impact on second language learning have emerged. At the same time, the world has also witnessed the growth of globalisation, European reconstruction, the demise of communism, extensive economic and political migration, greater mobility, and the rapid development of media technologies—all contributing to the relentless pace of global English (McKay, 2002). In other words, over the recent decades the world has transformed dramatically—it is currently distinguished by sociocultural and linguistic flexibility and diversity, where language learning , identity, and ethnicity have become multifaceted contemporary subject matters and the focus of considerable attention in the field of sociolinguistic. However, it is only recently that those engaged in the field of second language learning motivation have actually started to investigate what this evolving global phenomena may suggest for how scholars conceptualise the motivation to acquire proficiently in global English as second language for individuals wanting to gain global recognition or identity (Shafaei & Nejati, 2008). In other words, motivation

Description of what is Typical grief noting all manifestations Essay

Description of what is Typical grief noting all manifestations - Essay Example Grief is a process of healing oneself to become a part of life after losing someone close. Bereaved comes out of it after a specific time period but it manifests in his behaviors and reactions. This paper discusses some of these manifestations. â€Å"Depersonalization is a term used to describe the experience when oneself or one’s body feels somehow strange or unreal .Derealization is the term used to describe the experience when external reality seems strange or unreal† (Davies, 2004,p.42). Lindemann (1944, as cited in Worden, 2009) explained physical sensation of a bereaved as a reaction of the loss. A sense of depersonalization is one of them. For example, a bereaved told that he walked down the street and felt everything is unreal including himself. Such reactions are taken for granted but hold an important place in grieving process (p.23). Disbelief or denial is a common manifestation of grief. It happens when bereaved is shocked by sudden or unexpected news of death or loss. According to Worden (2009), people tend to deny the fact and show mistrust by saying, it can’t happen or informer is mistaken. A widow told him that after the death of her husband, she kept waiting for someone to wake her up and tell her that she was dreaming. Another explained, despite of her husband’s long sickness, she was not quite ready for his death (p.34). Idealization is very common behavior; people idealize their lost or separated partners. Bereaved forgets about the negative characteristics or faults of deceased. Only good and loveable things are remembered without any reservation (HBM, n.d). Demonization refers to blaming enemies or evil powers for the loss. According to Worden (2009) anger, if handled in ineffective way can lead to the situation in which bereaved direct the loss towards some other person and blame him for death. They believe that the person

The White Cube Museum Essay Example for Free

The White Cube Museum Essay Introduction: White cube was set up by art dealer Jay Jopling, an ex-Estonian and son of a Conservative MP who is married to artist Sam Taylor Wood. It was first opened in a small, square room in May 1993 in Duke Street. Indeed, it was the smallest exhibition space in Europe at the time, and yet, for such a small space white cube became, arguably, one of the most influential galleries of the past decade. Situated at 44 Duke Street, St James, one of London’s most traditional art dealing streets, surrounded by auction houses, old master galleries and specialist art bookshops.   The central concern of White cube was to create an intimate space in which an artist could present a single important work of art or a coherent body of work within a focused environment. In this regard, the gallery achieved its reputation by being the first to give one person shows to many of the so-called Young British Artist [YBAs]. Even when it moved to its present location at Hoxton Square, it still held on to its unique gallery rule that an artist could only be exhibited once. By this time, white cube had built up an international reputation for showing international artists such as Chuck Close, Richard Prince and Jeff Wall but interspersed with this Jay Jopling had also shown, cutting edge, YBAs including Gary Hume, Mona Hatoum, Marc Quinn and Sarah Lucas. Alfred H. Barr. Jr., director of the Museum of Modern Art, MoMA, is credited for transforming the white cube concept into a functionalist ideology that conveyed purity and restraint, hence setting up the canon for modern art. On the other hand, Carol Duncan has attempted to bring out the effect caused by MoMA’s imposition of the masculine gaze to modern art galleries. Indeed her writings have given feminists an impetus to show that the personal is political and hence, women can channel there own experiences to disrupt the masculinity of the museum’s space. Ideally, Carol Duncan challenges the white cube’s functionalist concept of purity and restraint by directing us to begin to think about ‘female form’ and its cultural significance. The concept of purity and restraint conveyed by the white cubes has its basis in the ideology that representations of the female body can be though to be less of a static object and more as a limit point or set of exclusions, for while an image of the body of a woman can represent all that is pure or worthwhile, it can also embody that which is thought to be the most contaminated and disgusting. It is this objectivism of the female body by male artists’ that Duncan describes as male artists’ attempts to reach abstraction. The white cube captures this abstraction in such a way that it bars women artists from admittance to its canon. She seems to portray the idea that this canon emanates from the view point of a heterosexual male audience whose desires activated the modernism of the white cube art concept. In essence Carol Duncan’s main critique of MoMA’s white cube is based from its perceived attempt to foster stereotypes in society. From her are led to imagine exhibition sites to be quite the opposite of the white cube, to be social spaces based on the model of a living, responsive, organic entity. This is because to her, the white cube deliberately restricts the range of sensorial input to the viewer as works are spatially isolated in uncluttered, pristine environments characterized by large expanses of bare, unadorned wall. The cool aesthetic of the modern art institution, to her, only serves to emphasize the architecture as a functional container and a set of solid surfaces. This makes the art museum appear like a ritual site whose aesthetic exhibition, courtesy of the white cube, distinguishes viewers from art works both conceptually and spatially, which is an ideal of the neutralized relationship between art and space. Emma Baker also presents a different angle to the critique on the white cube. She argues that by interpreting artistic statements concerning art and space within the expanded notion of interior space, better understandings and more appropriate solutions will result. This solutions are necessary because the modernist idea of a universalized and neutral environment for art as espoused by the white cube concept impinges on the interior space in the gallery, and therefore on the artwork. The idea of space itself is considered an ambiguity, and it is this ambiguity that the white cube concept capitalizes on, presenting an unobstructive gallery space characterized by sterile and lifeless walls. This is a marked contrast from the artists of the past who expressed their spatial concerns within the abstract notions of the interior, architecture, environment, and /or space; hence there is a lot of interest expressed by artists, in negotiating concerns associated with the physical, psychological, and experiential implications of space. In as much as Emma Baker declines to support the white cube concept, which has been the traditional approach of a modernist museum to the collection and exhibition of art work, she also does not go out to support the artists of the past since, according to her today’s museum’s privileging of newness, non-linearity, and post modernity seems to disavow the influence of history and the relevance of modernity. Her writings instead seem to allude to an approach which is concerned with the mediation of that art work to a diverse public, rather than the cultivation of the artist within a historical context. This is because, today architecture is the prevailing element that determines the quality and characteristics of art related spaces and therefore dictates the interrelation of art and space. Thus, because of the psychological, aesthetic, and behavioral implications, the notion of the interrelation of art and space needs to be considered within the complexity of interior space. Essentially, Baker advocates for a generic post modern approach style, which presents the concept of space in a fashion that is without precedent in architectural style, something which is widely apparent in recently constructed museums and shopping malls globally. And yet, the fundamental structure underlying these new effects can also be seen as maintaining clear connections with past incarnations of the institution’s built form. Precedents for this approach include the exhibitions from the Education and Community Program, such as Unspoken Truths (1993), and Once is Too Much (1997-1998). These exhibitions, and the programs of work from which they derived, set standards for education and community work within, rather than parallel to, the museums activities. Hence the idea of neutrality as espoused by the white cube is in this context dismissed within a design sensitive framework.   Furthermore, Emma Baker considers that one of the key functions of a museum of modern art, through the acquisition of art works, is to challenge rather than to reinforce assumptions about definitions of art and artists. This viewpoint contributes to make a powerful argument for a new way of looking and thinking about art that is open and inclusive rather than closed an exclusive. As such, this viewpoint employs features of modernity at a generally invisible albeit fundamental level. This is so in regard to history, display and communication on the one hand, so that on the other, it can attempt to undercut the problems of representation associated with modernity, by referencing a post modernity that denies both historical precedents and the connection between museums and modernity as a progress-oriented project. This is ironic in relation to modernism’s belief that ‘ornament is a crime’ because it   looks as if post modernity has been appropriated within Emma Baker’s view point not as a cohering style, or as a guiding principle, but as precisely that: adornment. In both asserting and critiquing the idealized modernity of white cube exhibition spaces through their strategies of display, Emma Baker’s viewpoint may be physical evidence for the argument that modernity and post modernity do not exist in a dialectical relationship, but as influences that overlap and compete for attention. In conclusion, it is important to note that both authors, Emma Baker and Carol Duncan attempt to critique the white cube’s concept of artworks that speak for themselves by employing neutrality to achieve the needed effect. Carlo Duncan approaches her criticism from the standpoint that rather than have museums with bare and unadorned walls, art exhibitions were designed to be   social spaces based on the model of a living, responsive, organic entity. Emma Baker on the other hand argues that what is essentially needed is some sort of mediation of that art work to a diverse public, rather than the cultivation of the artist within a historical context. Reference: Marie Fitzpatrick, D. The Interrelation Of Art And Space: An Investigation Of Late Nineteenth And Early Twentieth Century European Painting And Interior Space http://64.233.183.104/search?q=cache:StnTM_h7QVAJ:www.spokane.wsu.edu/Academics/Design/documents/Theses/d_fitzpatrick_10568509.pdf+Emma+Barker+*white+cubehl=enct=clnkcd=24gl=keclient=firefox-a Toorn, T. Sensing Bodies: Documentation, Preservation and Wearable Computer Art http://64.233.183.104/search?q=cache:ClLDm5PRsH4J:www.docam.ca/Pedagogie/Seminaire_2006/Tai_van_Toorn.pdf+Carol+Dunkan+*white+cubehl=enct=clnkcd=10gl=keclient=firefox-a

Taro Leaves Drying Kinetics and Monolayer Moisture Content

Taro Leaves Drying Kinetics and Monolayer Moisture Content INTRODUCTION |1 A study on the drying kinetics and monolayer moisture content of taro leaves This research was aimed to develop dehydrated products based on Taro leaves and finding out the effect of drying parameters such as loading density and temperature on that control the drying kinetics. To determine the end point of drying studies on the sorption isotherm was conducted. From the moisture sorption isotherm data, the monolayer moisture content was estimated by Braunauer-Emmett-Teller (BET) equation using data up to a water activity (aw) of 0.52 and monolayer moisture content was found to be 8.92 g water per 100 g solid for taro leaves. By using another most important model, GAB (Guggenheim-Anderson-DeBoer) model, using data up to aw=0.9, the monolayer moisture content of taro leaves was found to be 19.78g water per 100 gm solid. INTRODUCTION It is estimated that by 2020, the population of Bangladesh will be as high as 200 million, which means that there is a need to produce more food from the limited land resources. In this context, there is a need to explore alternate food crops, which could supply food in food insecurity situations. â€Å"Taro† can be the alternative to the other vegetables for developing and under developed country. Apart from acting as cheap energy and dietary source, this crop provides other micronutrients, vitamins and dietary fiber as well. In Bangladesh, taro is used as vegetable throughout the country. Corms and cormels are used as starchy vegetables whereas leaves and leaf stalks are used as ‘shak’. During famine, a large number of people reportedly survive simply on food materials made by boiling the corms, cormels, stolons, leaf stalks and leaves of different varieties of Taro. The subfamily Colocasioideae of family Araceae consists of three edible tubercrops, namely taro (Colocasia esculenta Schott), `tannia (Xanthosoma spp.) and giant Taro (Alocasia spp.). Among these crops, taro and tannin are cultivated to a larger extent, while giant taro is not as common as commercial crop like the other two. In general, these are crops of third world countries, particularly grown in Africa and Asia. About 88 % of the total world acreage is in Africa which produces about 80% of total production (Onwueme, 1978). Among the three crops, taro is more common in South-East Asia. It is one of the ancient crops with an interesting history blending with the evolution of agricultural systems (Gopalan et al., 1974). A large number of horticultural varieties of taro are widely cultivated in Bangladesh and still larger varieties grow wild. During the rainy season when other vegetables are in scarcity in Bangladesh this taro goes a long way to meet the demand for vegetables. The leaves, petioles, stolons, corms and cormels, and indeed all the parts of some taro are taken as food in large quantities by the rural population in our country. Hence the use of Taro as vegetables, both leaves and roots, in the diets of the people of our country assumes special and added importance. The taro has also medicinal value. Processed Bishknchu is used in Ayurvedic medicine for the treatment of rheumatism. Juice from petioles and whole leaves are used as antiseptic to check bleeding from minor injury in the rural areas of Bangladesh (Chowdhury, 1975). The possibility of wider use of the Taro leaves as vegetables crops in our country may be ascribed to their unusual environmental adaptability and ease of cultivation. The lowland types grow in standing water which is rarely possible for other crops. The taro can be produced with minimum capital investment. Growing of this crop does not require any special technological skill. Their keeping quality in most cases is excellent. The best way of preserving the leasfy vegetables is drying or dehydration. This process costs less, then other preserving methods and require simple instrument. The type and conditions of the blanching treatment prior to drying affect the retention of ascorbic acid, carotene, and ash in the dried vegetables. The sun-dried vegetables had inferior color, texture and acceptability compared to the vegetables dried in the cabinet dryer. In the mechanical dryer, desired temperature and airflow could be maintained. Compared to sun/solar drying, higher airflow and temperature can be used in mechanical drying. This leads to high production rates and improved quality products due to shorter drying time and reduction of the risk of insect infestation and microbial spoilage as well as minimum nutrient loss. Since mechanical drying is not dependent on sunlight so it can be done as and when necessary. Based on the above information, the present experiment was broadly aimed to study on development of shelf stable taro (Colocassia esculenta) leaves product. The specific objectives of this study are as follows: To determine the composition of fresh and processed Taro leaves To develop the isotherm To study the drying characteristics of taro leaves during mechanical and vacuum drying To study the storage stability of processed taro leaves Materials and methods 3.2.3 Sorption isotherm studies The moisture sorption properties of dried Taro leaves were determined at room temperature under conditions of various relative humidity (11-93% RH) in the vacuum desiccators. The various RH conditions were achieved in vacuum desiccators using saturated salt solutions. The following salt solutions (Table. 3.1) of known water activity were used for the study (Islam, 1980). Table 3.1: Water activity of saturated salt solution Petri dishes were used for preparing saturated salt solution. The various salts were put in the Petri dish and water is added to give a saturated condition. The method involved putting a small accurately weighed about 1g sample in a previously weighed Petri dish into desiccators contained saturated salt solutions. The sample and the solution was separated a perforated plate to avoid mixing. The desiccators were evacuated to less than 50 Torr. At various intervals, the vacuum was broken with air, the sample weighed and replaced in the desiccators, which was then re-evacuated. The sample was weighed daily in the initial period and less often, as the sample started to reach equilibrium. Weighing was continued until the sample weights were constant two days in row. In the mid-1970s, water activity came to the forefront as a major factor in understanding the control of the deterioration of reduced moisture, drugs and biological systems (Labuza, 1975). It was found that the general modes of deterioration, namely physical and physicochemical modifications, microbiological growth, and both aqueous and lipid phase chemical reactions were all influenced by the thermodynamic availability of water (water activity) as well as the total moisture content of the system. Control of initial moisture content and moisture migration is critical to the quality and safety of foods. Ideally, food manufacturers develop products with defined moisture contents to produce a safe product with optimum shelf- life. Quality and safety factors that the manufacturer must consider are microbial stability, physical properties, sensory properties, and the rate of chemical changes leading to loss of shelf-life. Water activity or the equilibrium relative humidity of a system is defined as: Where Vapor pressure of water in equilibrium with the dry system Saturation vapor pressure of pure water at the same temperature. Sorption properties of floods (equilibrium moisture content and monolayer moisture) are essential for the design and optimization of many processes such as drying, packaging and storage (Muhtaseb et al., 2002).The moisture sorption isotherms show the equilibrium amount of water sorbed onto a solid as a function of steady state vapor pressure at a constant temperature (Bell and Labuza, 2000). There are many empirical equations that describe this behavior, but the water sorption properties at various RHs should be experimentally determined for each material. The general shape of the isotherm, specific surface area of the sample, reversibility of moisture uptake, presence and shape of a hysteresis loop provide information on the manner of interaction of the solid with water (Swaminathan and Kildsig, 2001). Sorption properties are important in predicting the physical state of materials at various conditions, because most structural transformations and phase transitions are significantly affected by water (Roos, 1995). Langmuir (1917) developed an equation based on the theory that the molecules of gas are adsorbed on the active sites of the solid to form a layer one molecule thick (monolayer). The Brunauer-Emmett-Teller (BET) sorption model (Brunauer et al.1938) is often used in modeling water sorption particularly to obtain the monolayer value (Eq. 2.10) which gives the amount of water that is sufficient to form a layer of water molecules of the thickness of one molecule on the adsorbing surface (Bell and Labuza 2000, Roos, 1995). The BET monolayer value has been said to be optimal water content for stability of low-moisture materials (Labuza, 1975 and Roos, 1995). The BET equation was developed based on the fact that sorption occurs in two distinct thermodynamic states; a tightly bound portion and multilayer having the properties of bulk free water (Zografi and Kontny, 1986). The BET equation is: Where, = the measured moisture at water activity = the monolayer moisture content (the optimal moisture content for maximum storage stability of a dry food); c = the isotherm temperature dependence coefficient (energy constant) Vanchy (2002) determined the moisture sorption isotherm of Whole milk powder (WMP). The WMPs were stored at 20 and 35 °C under 11%, 22% and 33% relative humidity . The monolayer moisture content was 4.8%, (solids not fat basis) at 0. 11 using the BET equation and 5.1 % at 0.23 according to the GAB equation. Nikolay et al. (2005) determined the moisture equilibrium data (adsorption and desorption) of semi-defatted (fat 10.6 % wet basis) pumpkin seed flour using the static gravimetric method of saturated salt solutions at three temperatures 10 °C, 25 °C, and 40 °C, found that the equilibrium moisture content decreased with the increase in storage temperature at any given water activity. They fitted the experimental data to five mathematical models (modified Oswin, modified Halsey, modified Chung-Host, modified Henderson and GAB). The GAB model was found to be the most suitable for describing the sorption data. The monolayer moisture content was estimated using the Brunauer-Emmett-Teller (BET) equation. The BET model (Brunauer et al. 1938) gives the best fit to the data at aw of up to 0.5 (Bell and Labuza 2000, Roos 1995). Guggenheim-Anderson-de Boer (GAB) sorption model (Anderson 1946, Boer 1953, Guggenheim 1966) introduces a third state of sorbed species intermediate to the tightly bound and free states. The GAB equation has a similar form to BET, but has an extra constant, K (equation 2.11). BET is actually a special case of GAB. The GAB equation is: Isotherm equations are useful for predicting the water sorption properties of a material, but no equation gives results accurate throughout the entire range of water activities. According to Timmermann (2003), the GAB monolayer value is always higher than the BET monolayer value. Prediction of water sorption is needed to establish water activity and water content relationship for materials (Roos, 1995) Where m = the measured moisture at water activity; = the monolayer moisture content (the optimal moisture content for maximum storage stability of a dry food), =the GAB multi-layer constant; c=the isotherm temperature dependence coefficient (energy constant). The GAB model can be used to a maximum water activity of 0.9. The following procedure is suggested by Biozt (1983) to fit data on water activities and equilibrium moisture content. Equation (2.11) can be transformed as follows: Where Equation (2.12) indicates that GAB equation is a three-parameter model. The water activity and equilibrium moisture content date are regressed using equation (2.12) and values of three coefficients, and are obtained. From these coefficients, the values of k,, and c can be calculated. To overcome this weakness of the GAB equation, modifications of the equation have been proposed (Schuchmann et al. 1990; Timmermann and Chirife 1991). Timmermann and Chirife (1991) used one additional parameter in the GAB model and studied the so-called third stage of sorption using experimental data of starch with satisfactory results. Isotherm equations are useful for predicting the water sorption properties of a material, but no equation gives results accurate throughout the entire range of water activities. According to Timmermann (2003), the GAB monolayer value is always higher than the BET monolayer value. Prediction of water sorption is needed to establish water activity and water content relationship for materials (Roos, 1995). Results and discussion: The sorption isotherm is an extremely valuable tool for food scientist because it can be used to predict potential changes in food stability, for selection of packaging, for selection of ingredient and for predicting drying time. A sorption isotherm for dehydrated taro leaves obtained by Vacuum oven drying (VOD) was established to determine how the taro product will behave in a confined environment. To obtain the moisture sorption isotherm, moisture content (dry basis) versus water activity were plotted on linear graph paper (Figure 4.1). The results shown in Figure 4.1 (tabulated data given in Appendix-II, Table 2.1), indicate that samples absorb little water particularly at lower aw ( Figure 4.1 Graphical presentation of sorption isotherm of Taro The water sorption isotherm of taro follows the shape of the sigmoid type isotherm. The resultant curve is caused by the combination of colligative effects (physical properties of solution), capillary effects, and surface-water interactions (Bell and Labuza, 2000). A distinct knee usually indicates a formation of a well-defined monolayer. The monolayer moisture content was estimated using the Brunauer-Emmett-Teller (BET) equation. The BET equation is an extension of the Langmuir relationship that accounts for multilayer coverage. BET equation was used (eq. 2.10) to calculate monolayer moisture content (mo) and energy constant (C). mo represents the optimal moisture for maximum storage stability in the dry state. Results obtained from BET equation are shown in Table 4.2. Table 4.2 Data for BET and GAB methods From the slope and intercept of BET equation (Appendix II, Figure 2.1), monolayer moisture content and energy constant of taro leaves calculated for VOD samples. The monolayer moisture content of taro leaves was found to be 8.92g water per 100 g solid (Table 4.2). The calculated monolayer moisture content are greater than those found by Islam (1980) who reported 5.5 for potato slice and 6 for potato powder and by Kamruzzaman (2005) who reported 7.52 for aroids. Another important model of sorption isotherm behavior stated by GAB (Guggenheim-Anderson-DeBoer) in equation 2.11 and 2.12 to determine the monolayer moisture content of food products. This is very important for safe level of storage of food. Dry foods are usually considered to be most stable to chemical reactions if their moisture content is at or near the BET monolayer (Labuza et al., 1970). Usually air dried products are dried to moisture content corresponding to aw 0.6 (Nickerson and Sinskey, 1977). From this study it is seen that VOD taro leaves give 25% (Figure 4.1) moisture content at 0.6 aw. From this standpoint, freeze dried products are considered best for sorption studies (Islam, 1980). It may be mentioned here that the current study was concerned with adsorption isotherm so as to avoid risk due to hysteresis effect. At same moisture content adsorption path gives higher water activity than desorption path. Thus product dried to safe aw level according to adsorption isotherm will be even safer when it follows desorption path. After fitting data (Appendix II) the following figure was developed and from the developed equation the monolayer moisture content of taro leaves were found for GAB model. Fig. 4.2 Graphical presentation of GAB model of sorption isotherm From the developed Figure (4.2) and equation (4.1) the coefficients found, and were -0.121, 0.114 and -0.003 respectively (Table 4.2). Taking k= 0.9 and found the monolayer moisture content 19.78gm water per 100 gm solid. It is shown that the standard GAB equation is adequate to describe experimental data for water activity values up to 0.90 but fails to adequately describe the experimental data when data in the range of aw 0.9-1.0 are included in the calculation.