Assessment of airplane design, fabrication, and repair

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2009.Includes bibliographical references (leaf 43).Engineering programs are most often classes dedicated to how to design things, while the topic of reverse engineering or problem solving is rarely discussed. This unequal presentation of two sides of the same discipline limits the student's ability to completely understand the engineering process. This paper discusses all stages of airplane design, fabrication, and repair, and attempts to provide a comprehensive view of the overall procedure instead of just one aspect. In most cases, the Boeing 747 is used as an example, though most commercial aircrafts are built in a similar fashion. Once it has been decided to build a new airplane, the design stage can begin. The progression through conceptual design, preliminary design, and detail design can take anywhere from a few to several years depending on the complexity of the model. The fabrication stage slightly overlaps the detail design phase as coordination between engineering and manufacturing occurs. With one exception on the wing panels, the entire airplane is put together manually. This type of build process naturally leads to mistakes by human error. In order to remedy these problems, engineers inside the factory take responsibility for restoring the airplane to its original designed capacity. In this paper, each stage of airplane development from initial concept to final certification is presented in detail to offer a well-rounded assessment of the airplane construction industry.by Lauren Stolar.M.Eng

Gender Trespass and Masculine Privilege: “Male Trouble” in Jack Hodgins’s Spit Delaney’s Island

A question posed in the story "Separating," — 'Where is the dividing line?' — acts as a starting point from which to explore the dividing line between various sex/gender constructs in the collection of stories that makes up Jack Hodings's Split Delaney's Island. The differences between the ostensibly natural and the culturally constructed are explored in order to understand ideas and expressions of desire that are present in the stories in the collection. Using various recent theories concerning margins, peripheries, and centres to inform a reading of the stories in Split Delaney's Island allows one to explore and challenge what traditionally counts as viable notions of sexuality and desire. In particular, such an approach challenges notions of masculinity, male desire, and sexuality, or some combination of these. Hodgins's work challenges critics to expand and refigure modes of permissible literary criticism in Canada, particularly involving meanings of gender and masculinity

Social workers attitudes and perceptions toward transracial adoption

Overall attitudes, beliefs, and values have been shown to effect how individuals evaluate and process information. This knowledge is important and relevant to the practice of social work. Social workers are expected to put their attitudes, values, and perceptions aside when working with their clients. Attitudes are effecting processing and evaluation of events, therefore, it is imortant to understand the possible implications of workers perceptions and attitudes. Highly embedded attitudes toward transracial adoption, will influenceSocial workers behavior

Populus Fremontii Tree Ring Analysis and Semi-Arid River Water Source Variability over Time, San Pedro River, Arizona

Summer floods are an important source of sustained streamflow in arid and semi-arid rivers of the American Southwest and Northwest Mexico. The degree to which natural function versus human alterations influence the system is subject to debate. Environmental information in the tree ring cellulose of Populus can be used to investigate the variation in water sources over time in these areas. Past research has shown that streamflow sources in the San Pedro Basin of Arizona vary isotopically between a source water of basin ground water and a summer flood water source. This study uses isotopic analyses of Populus fremontii and atmospheric data in the San Pedro Basin to estimate the water source of the trees and the river water source condition. After analyzing weather data within the basin, an inversion of the Barbour oxygen isotope model using tree ring cellulose isotopes was used to obtain the water source isotopic composition. The variation in water source composition inferred from the model was then compared to the river composition over time. It was initially found that each site’s water source isotopic composition was significantly different from the source water. However, several water source isotopic compositions were found to be more negative than the known basin groundwater signature in each of the study sites. Following sensitivity analyses on various parameters within the model, it was seen that relative humidity has a strong influence on the determination of source water. Therefore, relative humidity must be an accurate measurement and is not considered to be so in this study. Furthermore, in order to understand the degree to which natural function versus human alterations influence the system, older Populus fremontii tree ring isotopes are needed, posing a question regarding the reliability of the species

Male–female separation with a genetic sexing strain of Medfly, Ceratitis capitata, based on the gene sw (slow)

The rate of development of the Medfly, Ceratitis capitata, slows down in the presence of mutation slow, sw. Separation of fast-developing males from slow-developing females is possible when this locus on chromosome 2 is linked by a translocation to the male determining chromosome Y. We report here the results obtained in an experiment aimed at improving male–female separation by lowering the rearing temperature.Lowtemperature treatmentswere applied to first and second larval stages.This resulted in an increase in the separation in the median time of popping of female and male larvae. The proportion of males accumulated when the females start popping was also affected but to a lesser extent. Experiments on the application of pulses of cold temperature later during larval development are in progress to further improve the separation between sexes using the genetic sexing strain based on the gene sw.Instituto de GenéticaFil: Viscarret, Mariana Mabel. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina.Fil: Stolar, Cristian Eric. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentina.Fil: Cladera, Jorge Luis. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Genética; Argentin

Supramolecular recognition of nucleobases in the solid state

Zagrijavanjem fizičkih smjesa komplementarnih nukleobaza potaknuto je njihovo supramolekulsko prepoznavanje u čvrstom stanju. Dobiven je dosad nepoznati 1:1 kokristal 9- metilgvanina i 1-metilcitozina. Njegova je kristalna struktura riješena pomoću podataka dobivenih difrakcijom rentgenskog zračenja na polikristalnom uzorku. Molekule 9- metilgvanina i 1-metilcitozina povezane su Watson-Crickovim načinom povezivanja koje uključuje tri međumolekulske vodikove veze. Ovi rezultati mogu biti značajni jer predstavljaju alternativan put nastanka supramolekulskih struktura koje su bile preduvjet za daljnju biološku evoluciju.Supramolecular recognition of complementary nucleobases was thermally induced in the solid state. Novel 1:1 cocrystal between 9-methylguanine and 1-methylcytosine was obtained. The crystal structure of new cocrystal was elucidated using laboratory powder X-ray diffraction. Molecules of 9-methylguanine and 1-methylcytosine are held together by Watson-Crick hydrogen bonding motif that includes three intermolecule hydrogen bonds. It is considered that these findings could be relevant as they stress out an alternative route of occurance of supramolecular structures that were prerequisite for biological evolution

"So what's the joke?" : locating Jewish-American female authorship

This thesis examines the fiction of three contemporary Jewish-American female writers, Grace Paley, Cynthia Ozick and Erica Jong, and locates their writing in the context of their quasi-double-marginalization--the yoking of their Jewishness and femaleness. Their texts illustrate their reaction to a history of patriarchal Judaism that relegates femaleness to the domestic sphere, and to a history of anti-Semitism that is marked by persecution, and, most explicitly, the Holocaust. An examination of the narrative strategics that these writers utilize--oral storytelling, traditional genre paradigms, and hyperbolic satire--illustrates their reaction to oppressive constructions of Jewishness--particularly Jewish femaleness--that have been authorized and promoted by such canonical Jewish male authors as Saul Bellow, Bernard Malamud, and Philip Roth. Paley, Ozick and Jong challenge the authority of their canonical male counterparts and ridicule their caricatures of Jewish women--particularly that of the ball-breaking "Jewish Mother." Their rewritings and inscriptions of Jewish-American femaleness reconstruct a frequently ignored immigrant domestic sphere, and the sexuality of the Jewish-American woman--whose sexuality has been dismissed by the Jewish male desire for the shiksa. And yet, their texts also remind us that Jewish-American female writers are not relegated to the domestic sphere, nor do they lack authority