Precipitation of Calcium Carbonate in Different Environments

Precipitation of Calcium Carbonate in Different Environments Most confinement studies have focused on the effects of freezing and melting pure liquids like water, hydrogen and helium; inert gases and organic liquids in nanoscale pores. Thus, many studies have shown that melting points and enthalpies of fusion in nanoscale crystals can differ significantly from their bulk scale counterparts. It has been shown (Christenson H.K., 2001) that melting points decrease in crystalline solids embedded within nanoporous matrices and melting point depression becomes more significant with decreasing size of pore. However, the confinement has other less known effects that will be discussed in this report. The study of biominerals shows that many biological reactions take place in specific spaces which can provide a structural and chemical environment that enables the controlled formation of crystals. The formation of biominerals in these specific volumes assigns them certain characteristics which would change if the growth environment changed. This kind of organization suggests that there should be similar systems which are available and exploitable in synthetic materials chemistry. Some studies have focused on these changes and have attempted to confine compounds such as calcium carbonate or calcium phosphate. These studies have been conducted in synthetics systems to observe the differences on their crystallization in confinement and in bulk solutions. The results obtained in these studies are discussed in this report. There have been numerous investigations into the precipitation of calcium carbonate in different confined environments. For example, it has been grown within regular arrays of picoliter droplets created on patterned self-assembled monolayers (SAMs) (Stephens, C. J., et al. 2011). Figure 1. SAM deposited on a gold-mica substrate with a droplet of CaCO3 solution by passing a Na2CO3/CaCl2 solution across the SAM. (copied from reference 6) It is also possible to confine CaCO3 within the confines of a annular wedge, formed around the contact point of two crossed half cylinders. The cylinders are functionalized with SAMs. (Stephens, C. J., et al. 2010). Formerly, CaCO3 biomineralization was considered to be based in a combination of ions pumped into the mineral deposition site. However, CaCo3 confinement has helped to increase our understanding of biomineralization processes due to a higher study of its formation. Currently, it is well known that calcite and aragonite formation in biological systems frequently proceeds via ACC (amorphous CaCO3) precursor. It was shown (Stephens, C. J., et al. (2011) how the crystallisation of CaCO3 was slower in droplets than in a bulk solution. This allows us to observe the mechanism of crystallisation more easily and then study the different stages of the process or even discover new polymorphs. The research shows that the crystals that had precipitated within the droplets were quite different in morphology and were smaller than those precipitated in bulk. While the crystals precipitated in bulk solution were rhombohedral calcite crystals, most crystals formed in the droplets were tetrahedral ACC crystals. The explanation for these results is that the rate of crystallization of the ACC phase decreases in confinement. In bulk solution, the tetrahedral growth form converted into the more common rhombohedral morphology faster than in the droplets because the lifetime of the ACC precursor phase increased in small volumes. In particular, precipitation reaction of CaCO3 terminates at an earlier stage of crystallization in SAMs than in the bulk solution. Thus, under the limited reagent conditions, we might be able to observe the frozen intermediate and then, better understand its mechanism of crystallization. Other work has confined the CaCO3 in phospholipid bilayer vesicles (Tester C., Ryan E. Brock, et al. 2011). The results obtained are similar to those obtained in droplets: confinement allow the stabilization and control transformation of metastable amorphous precursor phases of calcite. Figure 2. Phospholipid bilayer vesicle (liposome) (copied from reference 18) Liposomal encapsulation offers excellent control over calcite nucleation and growth. CaSO4 was also confined in a annular wedge formed around the contact point of two crossed half cylinders (Wang, Y. W., H. K. Christenson, et al. 2013). A remarkable stabilization of the metastable phases amorphous calcium sulfate and calcium sulfate hemihydrates was observed. Confinement caused changes in the crystal shapes, sizes and observed polymorphs. The effect of confinement on Calcium Phosphate has also been studied. The importance of Calcium Phosphate confinement is highlighted by the fact that it allows understanding of bone and teeth structure and its formation mechanism (Cantaert B., Elia Beniash et al. 2013). By precipitating calcium phosphate within the pores of track-etched membranes, it is demonstrated that the formation of polycrystalline hydroxapatite and octacalcium phosphate (results of the crystallization of calcium phosphate) occurs by means of an intermediate amorphous calcium phosphate which is significantly stabilised in confinement. In addition, it is shown that in confinement the spatial constraints can provide a more organised structure of apatitic crystals because preferred orientations of the calcium phosphate nanocystals might appear. This research shows that orientation of the polycrystalline hydroxapatite in confinement is comparable or even superior to that seen in bone. Figure 3. Precipitation of CaPO3 within membrane pores (copied from reference 1) Some other studies have also reported that solid crystallization within nanometer-scale often exhibit preferred orientations with respect to the direction of the pores. Organic crystals were grown in the porous polymer monoliths and it was shown that pore direction affects the orientation of the nanocrystal. (Hamilton et al. 2012). Moreover, it is demonstrated that the sizes of crystals embedded in pores and the polymorph stability and selectivity during crystallization are affected by the pore size. The importance of confinement is explained through the crystallization processes since most of biological and chemical reactions can be affected by confinement, due to the changes in stability, morphology, polymorph, orientation, polycrisystalline character of crystals and also in the rate of crystallization. Indeed there are many crystallization phenomena that we cannot describe correctly from bulk solution. In conclusion, the confinement effects are important in general material synthesis since many optical, ferroelectric, electronic and magnetic proprieties of crystalline material depend on the control of the polymorphic forms of materials. Moreover, the study of early stages crystal growth is hard because they are transient and form randomly. Hence, to study the different polymorphic forms and orientation of crystals, it will be useful for solid crystallization to be conducted in localized volumes.

Of Mice and Men Character Analysis: Loneliness Essay

In Of Mice and Men many characters are lonely or at least act that way. The characters I think are lonely are Lennie, George, Candy, Crooks, and Curley’s Wife. The loneliness in the story is what causes most of the conflict in the story. Everyone in this story is lonely or must have been lonely. I think loneliness is one of the most important parts of this story. Lennie is one of the loneliest characters in the book. He makes friends with animals, he likes to pet them and talk to them even if they are dead. Him being lonely even caused him to get trouble in weed. As a bright side to it, as result he meets his best friend, George, who helps him through the rest of the story. It is truly the best relationship throughout the whole book. Lennie however is still lonely with George. When they get to their new job he gets into even more trouble due to his loneliness; first killing his pup followed by doing the same to Curley’s Wife. Crooks is lonely, however I think he probably most times is just overlooked. No one wants to be with him because of his race. This does take place when there was still segregation. Even his room is set aside from the rest. While everyone sleeps in the bunk house he sleeps out in the stable with the horses. Then one of the only times they spend time with Crooks, in my opinion, was not a pleasurable experience for him. Candy had his dog. Which he must have really liked and he must have had it for a long time because when everyone else was sick of the dog he still kept him around. This is why I think Candy was sad during the duration of the story or before. Eventually he does let go of the dog but he can’t even kill it. Curley’s wife always acts like she is lonely. I say she is most likely acting because there is a possibility that she is the kind of narcissistic person who always needs more and more attention. She is always â€Å"looking for Curley† and she ends up mainly just taking to whoever she finds. She even goes as far as to offer Lennie to feel her hair. At one point at her life she even had the chance to become an actress where she would have been able to reach the maximum level for attention. She had this once in a life time opportunity stripped from her by her mother. That’s why I believe she feels she needs all the attention she actively seeks out. George in the story has only one true friend, Lennie. This friendship is only out of pity, but I don’t think George would purposefully abandon Lennie. George keeps Lennie in good standing with other people and tries to keep him out of trouble. George does get along with the other characters but I don’t think any of them really are a true friendship like what he has with Lennie. The loneliness progress the story like so. Lennnie’s solitude and love to feel soft things causes the accident in Weed with the girl’s dress. George’s seclusion, supervision, and companionship with Lennie grounds George to be entangled with him. Lennie again being desolate makes him ask George for one of Slim’s pups. He kills this pup on accident after it bites him. He is sitting in the barn thinking about what he had done and even talks to the deceased puppy. Curley’s wife finds him in the barn and in a way tries to comfort him. Lennie being the rough person he unfortunately is kills her on accident. All of these events were product of someone feeling alone. As this paper has thoroughly shown most of the characters in Of Mice and Men where lonely and were at one point in their life. All of the conflict originates in someone’s search for attention, love, or friendship. That the main component at the core of the story is loneliness.

Effectiveness of 4p’s in Terms of Mch and Education Essay

Conditional cash transfers (CCTs) are among the most popular social protection schemes today. Promoted by multilateral institutions, notably the World Bank, CCTs have been adopted in at least 30 countries as of 2008, with further ones expected to follow suit in the coming years (WB‘s CCT Webpage). The map below shows these country-adopters. CCTs are grounded on the principle that human capital accumulation is a development vehicle which can be achieved by providing money to poor households, often to women, on conditions that they ensure children‘s regular attendance in school, accompany them to health clinics, and participate in classes and workshops on topics related to health, nutrition, and sanitation (St. Claire 2009: 177; Bradshaw 2008: 188; Hall 2006: 691). Citing the experiences of Latin American countries, particularly Mexico and Brazil, advocates have repeatedly claimed that CCTs are an effective and efficient means of reducing poverty and hunger, keeping childre n in school, enhancing the use of preventive healthcare, empowering women, and increasing the freedom of poor households to invest in their varied needs (WB‘s CCT Webpage; ECLAC 2004). No wonder, with the Millennium Development Goals (MDGs) deadline getting near, CCTs have been in vogue in a number of countries, including that archipelagic country in the east—the Philippines. In view of the worsening poverty situation and the MDG targets, the Philippine government ran a pilot CCT project in 2007, targeting 6,000 poor households in two provinces and two cities. It proceeded to implementing a full-scale program in 2008, calling it Pantawid Pamilyang Pilipino Program (4Ps) and targeting 320,000 additional households. When Benigno Aquino III was elected president in 2010, he decided to sustain his predecessor‘s 4Ps, and further expand its coverage so that when he bows out of the presidency in 2016, it will have reached a total of 4.3 million households (PCIJ 2011). Quoting the Philippine Development Plan 2011–2016, CCTs are the ―cornerstoneâ€â€" upon which the government ―has anchored [the] epic battle against poverty in the landâ€â€" (ibid.). This research has avoided the usual route of scrutinizing the implementation and (non)impact of CCTs in particular, and of development programs in general. It has taken one step back, and examined the factors that influenced or helped shape the government‘s decision to adopt CCTs in a country marked by a long history of poverty and inequality, and was once described as the Latin America in Asia1. The interest on this topic grew out of the observation of the government‘s continued adherence to the so-called residual type of social policy and social provision despite the lessons learned from and the criticisms hurled at past and on-going initiatives. It is in fact worth noting that the 4Ps which of late is called Pantawid Pamilya, is just one of the targeted and pallia tive poverty reduction measures pursued in the country. An earlier one, and internationally acclaimed at that, is the Kapit-Bisig Laban sa Kahirapan (Linking Arms Against Poverty) or KALAHI which has been the flagship poverty reduction program since 2003. A critical review of the KALAHI program reveals that its overall intervention does not offer a more permanent and effective way out of poverty because it lacks coherent plans and mutually supporting projects; and that its social protection component is neither broadly implemented nor viewed to provide permanent economic opportunities for the poor to accumulate assets and to engage in permanent income generating activities (Lim 2009: 29). An assessment of the Philippines‘ performance vis-à  -vis the MDGs supports this analysis. It stresses that†¦ Social protection in the Philippines is not universal; it is simply a bundle of safety net measures targeted at the poorest of the poor. It is [neither] a rights-based entitlement for all citizens†¦[nor a determined effort to] address the structural causes of poverty†¦Since it only targets the ―poorest of the poorâ€â€", many poor remained excluded from the government‘s anti-poverty programs. (Serrano in S ocial Watch Philippines 2010: 23) The analytical position adopted here is that ―policy choices are very politicalâ€â€" no matter how they are couched in technocratic jargon and touted as neutral (Fischer 2010: 40). As further explained, ―social policies are the outcomes of political bargains and conflicts since they touch upon power in society—its distribution and accessibility to different political actorsâ€â€" (Mkandawire 2004: 11 and 12). It is therefore imperative to unravel the interplay of different political processes, institutions, and actors, along with their diverse agenda and ideological persuasions in order to gain a better understanding of social policy choices. This research posits that the Philippine government‘s decision to adopt CCTs reflects the unchanged social policy trajectory marked by the tendency towards targeted, palliative, and supposedly apolitical social provision, not to mention externally-influenced, drawing ―encouragementâ€â€" and support from multilateral institutions, all at the expense of structural reform and redistribution (i.e., asset reform, employment creation, recall of unfair international trade rules and agreements). This trajectory has been defined by the interaction of various political institutions, also called ―the rules of the gameâ€â€", as well as actors, notably the elites whose longstanding dominance in the political and economic arenas has compelled and enabled them to suppress or overturn reform efforts that threaten their position and hold of power. That being said, CCTs paint a bleak picture for the long-term solution to poverty and inequality in the country mainly because like many other World Bank/multilateral donor-backed initiatives, they preclude rationalizing and confronting the structural roots of these problems. Framed in a way that appeals to the elites, middle class, masses, policymakers, bureaucrats, academics, and even a number of progressives—a program that addresses the laziness of the poor by requiring them to do something in exchange for some amount; a program that invests in the well-being of children; a program that efficiently uses the limited resources of government; a program that is supposedly ―apoliticalâ€â€", ―neutralâ€â€", or ―non-partisanâ€â€" and thus effectively reduces the likelihood of manipulation by politicos—a broad agreement of outright support for Pantawid Pamilya has been created despite warnings that it may only serve the Washington Consensus agenda of limiting the state, leaving the market to take care of income and welfare distribution, and granting mere safety nets to people who lose out in the process. Pantawid Pamilya is nothing but a continuation of the purportedly apolitical social policy of the country, and as such, runs the risk of obstructing government and society from going beyond palliatives and undertaking the untidy process of structural reform and distribution. With a situation like this, it is not to be expected that the program will catalyze the shift towards a redistributive and/or universal social provision. UNDP‘s Human Development Reports Webpage The Philippines is a country in the Southeast Asia in the western part of the Pacific Ocean. Its population based on the 2007 census is 88.5 million, of which 44.8 are males and 43.8 are females. Its average population growth rate as of that same year is 2.04 which registers a .32 decrease from 2000‘s 2.36. (NSO Website) Based on World Bank records, the growth in the country has been averaging around five percent over the last 10 years, except in 2010, where it has reached 7.6 percent, the highest in 30 years. Despite this positive picture, however, poverty continues to plague the country, while inequality remains a huge obstacle in achieving major strides in poverty reduction. The 2009 Official Poverty Statistics, the latest poverty report of the National Statistical Coordination Board, reveals that poverty incidence among the population has declined from 33.1 percent in 1991 to 24.9 percent in 2003, 26.4 in 2006, and 26.5 in 2009. Nevertheless, there still remains more than a quarter of the population, or roughly 23.14 million Filipinos livening in poverty. As for subsistence incidence among the population, the figures have decreased from 16.5 percent in 1991 to 11.1 in 2003, 11.7 in 2006, and 10.8 in 2006. As often the case, the official report differs from the unofficial report, especially if the bases are the perceptions of the poor themselves. Based on the survey conducted by the Social Weather Stations, self-rated poverty has ranged from 46 to 72 percent between 1991 and 2009. These numbers are obviously way about the official estimates. Within that period, overall self-rated hunger has averaged at 13.3 percent, of which moderate hunger has roughly been 9.8 percent, and severe hunger, 3.4 percent. Moderate hunger is when a family went hungry at least once in the last three months, while severe hunger is when a family often went hungry in the last three months. (SWS‘ Social Weather Indicators Webpage ) Inequality has shown a downward trend, but despite this decreasing gini ratio—from 0.4605 in 2003 to 0.4580 in 2006 to 0.4484 in 2009—it is still highest among the members of the Association of South East Asian Nations (UNDP as cited in NSCB 2011: 8). For instance, for the year 2009, Indonesia, Thailand and Vietnam recorded a gini ratio of 0.394, 0.425, and 0.378, respectively (ibid.). In terms of the Human Development Indicators, on one hand, the country‘s performance has been promising. Its score has consistently increased from 0.550 in 1980 to 0.571 in 1990, 0.602 in 2000, 0.641 in 2010, and 0.644 in 2011, although these are still below the global and the East Asia and the Pacific averages (UNDP‘s Human Development Reports Webpage). – 5 – It is also important to take into account the spatial dimension of poverty. The regions with highest poverty incidence by families are the Caraga Region (39.8%) and the Autonomous Region of Muslim Mindanao (38.1%), while those with highest number of poor families are Central Visayas (415,303) and Bicol (385,338). The regions with highest subsistence incidence are the Zamboanga Peninsula (18.6%) and Northern Mindanao (15.6%), while those with the highest number of subsistence poor families are Central Visayas (181,649) and Bicol (137,527). Almost 40% of the income poor families are in Luzon, and 40% of the subsistence poor families are in Mindanao. (NSCB‘s 2009 Poverty Statistics Webpage) Moreover, majority of the poor are still located in the rural area with figures that have remained in the 70-percent-mark since 1985 based on the estimates of Balisacan (2006). (Emma_s_RP_Final_Draft_Nov_2011)

My First Collegiate Academic Goal - 1691 Words

My first collegiate academic goal is: I will earn at least an 80 percent on my first biology and statistics exams. Being that I truly love both math and science, receiving superb grades on my first exam for these two are extremely important to me because they are hand-and-hand at placing for the second hardest classes thus far in college (in my personal opinion). Achieving this enabling goal would motivate me to strive for higher grades in the near future, helping me believe that I could do much better in order to attain a great GPA, so that I could get into medical school after receiving my undergraduate degree. Practicing my study habits will construct the permanent foundation of how I progress as a college student. How will I do so? The first action step that will be made to reach this goal is to sit in the front of the classroom. 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