In order to study the different social networks and institutions that shape the access to work and working conditions for the undocumented Bolivian migrant workers in Sweden, I have a conducted a qualitative research. This research specifically looks into how the Bolivian social networks in Stockholm are organized in terms of the access to labor market for undocumented immigrants from Bolivia. Another research dimension will be to explore the social relationships within these social networks and their internal hierarchy. The eight conducted interviews of undocumented, and previously undocumented, Bolivian migrant workers have determined the perception of the undocumented migrants’ life and working conditions. Through their testimonies I have grasped the information of what kind of social networks operate among the undocumented Bolivian labor migrants in Stockholm. With four interviews directed to four labor union representatives there has also been unraveled what the relationship are between the Bolivian social networks and the formal Swedish labor unions, and reversely. Actor network theory has been used as a perspective and a tool to examine the undocumented migrants’ perceptions of the main actors within these networks. The role of the social networks has, in terms of access to the labor market, a big influence on the undocumented Bolivian migrants and how they perceive and approach the Swedish labor unions.

Parodontit är en kronisk inflammatorisk sjukdom, som orsakas av patogena bakterier som fäster på tändernas ytor, där de bildar plack. Sjukdomen kan förebyggas genom god munhygien. Syftet med studien var att beskriva och jämföra parodontit relateradkunskap och dess relation till munhygiensvanor hos patienter före och 1-år efter icke kirurgisk parodontal behandling utförd av tandhygienist samt jämföra om det föreligger någon skillnad i kunskap efter behandling mellan två olika munhälsoundervisningsprogram. Ett ytterligare syfte var att beskriva om det föreligger någon skillnad i kunskap om parodontit med avseende på ålder, kön och utbildningsnivå. Studien var en beskrivande, jämförande studie med kvantitativ ansats och en del av en experimentell tvågruppsstudie.Urvalet bestod av 113 individer, 60 kvinnor och 53 män, i åldern 20-65 år som var remitteras till en specialistklinik i parodontologi. Av de 113 studiedeltagarna randomiserades 57 personer till ett individuell skräddarsydd munhälsoundervisningsprogram och 56 personer till ett standardiserat munhälsoundervisningsprogram. Ett frågeformulär med 11 påståenden gällande kunskap om parodontit och ett påstående om tandborstfrekvens samt ett påstående om approximalrengörning användes.Resultatet visade att patienterna hade mer kunskap efter icke kirurgisk parodontal behandling, men det fanns ingen skillnad mellan undervisningsprogrammen. Inget samband påvisades mellan kunskap om parodontit och utbildningsnivå, kön och ålder. Studien visar att både individuellt skräddarsydd munhälsoundervisning och standard munhälsoundervisning ledar till en ökad kunskap om parodontit mellan deltagarna.

Research was performed to study the particle adhesion on the wafer surface after the chemical-mechanical polishing (CMP) process. The embedded particles can be abrasive particles from the slurry, debris from pad material, and particles of film being polished. Different methods of particle removal mechanism were investigated in order to find out the most effective technique. In post-CMP cleaning, surfactant was added in the solution. Results were compared with cleaning without surfactant and showed that cleaning was more effective with the combined interaction of the mechanical effort from the brush sweeping and the chemistry of the surfactant in the solution (i.e., tribochemical interaction). Numerical analysis was also performed to predict the particle removal rate with the addition of surfactants. The van der Waals forces present in the wafer-particle interface were calculated in order to find the energy required to remove the particle. Finally, the adhesion process was studied by modeling the van der Waals force as a function of separation distance between the particle and the surface. The successful adaptation of elasticity theory to nanoparticle-surface interaction brought insight into CMP cleaning mechanisms. The model tells us that it is not always the case that as the separation distance is decreased, the attraction force will be increased. The force value estimated can be used for slurry design and CMP process estimation.

To improve the wire bondability, interfacial adhesion and popcorn cracking resistance in the packaging processing of IC and MEMS chips, this thesis utilized oxygen and helium plasmas to modify and clean the surface of metal pads. The influences of the plasma cleaning time, metal pad materials and wire bonding time/temperature/power on the strength of wire bonding were investigated. Two different wire materials (Al wire with 32 £gm in diameter and Au wire with 25 £gm in diameter) were bonded on the surface of Al, Au and Pt metal pads using a commercial ultrasonic wire bonder (SPB-U688), respectively. The pull strength detection of the implemented micro joints is characterized by an accurate pull strength testing system (Dage SERIES-4000). Based on hundred measurement results, this research has three conclusions described as follows. (I) The pull strength of Au pad is higher than that of Al and Pt pads no matter with the plasma cleaning process or not. The maximum pull strength (12.286 g) can be achieved as the surface of Au pad was modified by the helium plasma for 180 seconds. (II) Helium plasma cleaned wafer can obtain larger improvement of pull strength than that of the oxygen plasma under the same plasma time. However, this result can not be concluded in Al and Pt pads. (III) The optimized wire bonding time/power of the Au, Al and Pt pads are 0.07 s/2.1, 0.05 s/0.6 W and 0.03 s/2.7 W, respectively.

Studies show that the use of cleaning products is related to adverse respiratory health effects ranging from irritation to asthma. Yet exposure to these chemicals is poorly understood. This dissertation summarizes the current state of knowledge of inhalation exposure to toxic chemicals in consumer cleaning products. An improved two-zone model that treats personal air space as distinct from bulk room air is presented. The model accounts for air exchange between the two zones, dynamic source characteristics (i.e., the time-varying liquid concentrations and emission rates of pollutants within a mixture), and the characteristics of chemical use (e.g., how frequently a cleaning chemical is applied to a new area). To assess exposure to cleaning products and validate the improved two-zone model twenty-three experiments, encompassing six cleaning scenarios, were completed in an environmentally-controlled chamber with a thermal mannequin. Then, the model was used to predict exposure for four hypothetical cleaning scenarios and compared against other models. The model's applicability is restricted by limited data available for parameterization. At low air exchange rates gas-phase experimental results show concentrations in the breathing-zone of the mannequin exceeded concentrations predicted by the well-mixed model by factors up to 2.1. Breathing-zone concentrations also exceed those measured at centralized room monitors by factors up to 6.1. Thus, studies that use the centralized room monitors or the well-mixed model as a surrogate for breathing-zone concentrations could potentially underpredict exposure at low air exchange rates. The two-zone model provides the best prediction of exposure to cleaning tasks, at low air exchange rates. The next best model is the well-mixed model with an exponentially decreasing emission rate, followed by the well-mixed model with a constant emission rate. At high air exchange rates the well-mixed assumption appears to be valid. The inner-zonal volume and inter-zonal air exchange were independent of fresh air ventilation rate. But both were dependant on the mannequin's body position, with standing having the highest inner-zonal volume and lowest intra-zonal air exchange rate of the three body positions investigates (standing, bent over 45°, and hands and knees). / text

Poultry transport coops are rarely washed and demonstrate to be a major point of broiler carcass contamination. Our laboratory hypothesized that foaming disinfectants and cleaners commonly used within processing plants may be used to clean and disinfect poultry transport coops. The objective of this study was to evaluate treatments consisting of a low-pressure water rinse (LPWR), a foaming additive alone, foaming cleaner or peroxyacetic acid with a foaming additive to reduce bacteria on broiler transport coops. A high-pressure water rinse (HPWR) applied prior to and following treatments was also evaluated. Homogenized feces was evenly applied to the floors of pre-cleaned transport coops and allowed to dry. The first study used fresh layer feces and evaluated the treatments ability to reduce aerobic bacteria from the manure. The second study added a HPWR step to determine whether this technique would reduce bacteria. In the third study, Salmonella Typhimurium was added to the homogenized fecal slurry to evaluate how effectively these methods reduce aerobic bacteria and Salmonella on coop surfaces. The field study utilized laboratory treatments proven to be most effective on freshly soiled broiler integrator coops. All foaming treatments were applied using a compressed air foam system (CAFS) using a 1 inch fire hose. Ten minutes post-treatment, all surfaces were rinsed with a LPWR for 30 seconds to remove residual disinfectant. Samples were collected from the transport coops prior to and following treatments utilizing a flame sterilized 5 x 5 cm stainless steel template and a gauze swab pre-applied with buffered peptone water. All samples were stomached, serially diluted, spread plated onto agar plates, incubated for 24 h at 37° C and enumerated. The foam cleaner and peroxyacetic acid with a foam additive significantly reduced (P < 0.05) aerobic bacteria up to 4.84 to 5.17 logs, respectively when compared to the LPWR. The addition of a HPWR following product application significantly reduced bacteria on integrator coops, in the field study, but didn’t improve efficacy of our treatments in laboratory trials. These data suggest that a CAFS may be used in combination with disinfectants and cleaners to reduce bacteria on poultry transport coops.

Contaminated environmental surfaces can be a means of transmission of Clostridium difficile spores in health-care facilities. The study objectives are to assess the value of the UV marker as an audit tool for improving housekeeping compliance and to compare microfiber and cotton cloths for removal of Clostridium difficile spores from surfaces. A lotion visible only under short-wave UV light (UV Marker) was applied to different surfaces within the patient’s washrooms on consecutive week days, over a twenty-four week period. The Study included three Arms: Arm one received feedback for 24 weeks , Arm two received feedback for the first 12 weeks and Arm three was given feedback for the last 12 weeks based on UV Marker results. The visual audit resulted in a cleaning compliance of 55%; whereas, feedback with the UV Marker led to a housekeeping compliance of 90%. The UV marker is a better audit tool than visual inspection for improving cleaning compliance of housekeeping staff. The use of microfiber cloths may enhance efficiency of microbial removal during surface cleaning.

Craftsmen of past generations built to last, and the brick buildings they constructed can last for centuries if they are not mistreated. Although brick masonry is one of the most durable building materials, its durability can be threatened by improper cleaning and repointing techniques and materials. Many brick surfaces have been--and currently are being--disfigured, and the rate of deterioration often accelerated, because of the lack of knowledge of proper preservation techniques for historic bricks and mortar.This field guide provides a single source of information regarding inspection of historic brick buildings; the causes of deterioration, diagnoses and treatments; appropriate materials and methods for repointing; various cleaning methods; and surface coatings (including waterproof and water-repellent coatings, paint and stucco). This manual can be used to assist persons responsible for the care of old and historic brick buildings: owners of houses or commercial buildings, administrators, architects, contractors, and anyone else who wants to maintain or sympathetically restore or rehabilitate brick buildings.While masonry work generally should only be done by professionals, this field guide will enable a building owner or administrator to understand proper preservation techniques and oversee the project to ensure that the architect or contractor is following the recommended preservation procedures. The Mississippi Department of Archives and History will use this creative project as a reference manual and as a handout to persons undertaking restoration of historic brick buildings.Historic architecture is a viable link between generations of the past and those of the present and future. Proper maintenance and restoration techniques can ensure that a historic brick building will endure for generations to come. / Department of Architecture

Contaminated environmental surfaces can be a means of transmission of Clostridium difficile spores in health-care facilities. The study objectives are to assess the value of the UV marker as an audit tool for improving housekeeping compliance and to compare microfiber and cotton cloths for removal of Clostridium difficile spores from surfaces. A lotion visible only under short-wave UV light (UV Marker) was applied to different surfaces within the patient’s washrooms on consecutive week days, over a twenty-four week period. The Study included three Arms: Arm one received feedback for 24 weeks , Arm two received feedback for the first 12 weeks and Arm three was given feedback for the last 12 weeks based on UV Marker results. The visual audit resulted in a cleaning compliance of 55%; whereas, feedback with the UV Marker led to a housekeeping compliance of 90%. The UV marker is a better audit tool than visual inspection for improving cleaning compliance of housekeeping staff. The use of microfiber cloths may enhance efficiency of microbial removal during surface cleaning.

The remarkable attachment system of geckos has inspired the development of dry microfiber adhesives through the last two decades. Some of the notable characteristics of gecko-inspired fibrillar adhesives include: strong, directional, and controllable adhesion to smooth and rough surfaces in air, vacuum, and under water; ability to maintain strong adhesion during repeated use; anti-fouling and self-cleaning after contamination. Given these outstanding qualities, fibrillar adhesives promise an extensive range of use in industrial, robotic, manufacturing, medical, and consumer products. Significant advancements have been made in the design of geckoinspired microfiber adhesives with the characteristic properties listed above, with the exception of the anti-fouling and self-cleaning features. The self-cleaning mechanism of the gecko’s adhesion system plays an important role to its ability to remain sticky in various environments. Similarly, enabling self-cleaning capability for synthetic microfiber adhesives will lead to robust performance in various areas of application. Presently, the practical use of fibrillar adhesives is restricted mainly to clean environments, where they are free from contaminants. The goal of this thesis is to conduct a detailed study of the mechanisms and mechanics of contact-based self-cleaning of gecko-inspired microfiber adhesives. This work focuses on contact self-cleaning mechanisms, as a more practical approach to cleaning. Previous studies on the cleaning of microfiber adhesives have mostly focused on mechanisms that involve complete removal of the contaminants from the adhesive. In this thesis, a second cleaning process is proposed whereby particles are removed from the tip of the microfibers and embedded between adjacent microfibers or in grooves patterned onto the adhesive, where they are no longer detrimental to the performance of the adhesive. In this work, a model of adhesion for microfiber adhesives that take the deformation of the backing layer under individual microfiber is developed. The dependence of adhesion of microfiber adhesives on the rate of unloading is also modeled and verified using experiments. The models of adhesion presented are later used to study the mechanics of contact self-cleaning of microfiber adhesives. Three major categories of self-cleaning are identified as wet self-cleaning, dynamic self-cleaning, and contact self-cleaning. A total of seven self-cleaning mechanisms that are associated with these categories are also presented and discussed. Results from the self-cleaning model and experiments show that shear loading plays an important role in self-cleaning. The underlying mechanism of contact self-cleaning due to normal and shear loading for spherical contaminants is found to be the particle rolling between the adhesive and a contacted substrate. Results from the model and experiments also show that small microfiber tips (much less than the size of the contaminants) are favorable for self-cleaning. On the other hand, large microfiber tips (much larger than the size of the contaminants) are favorable for anti-fouling of the microfiber adhesive. Results from this work suggests that the sub-micrometer size of the gecko’s adhesive fibers and the lamellae under the gecko toes contribute to its outstanding self-cleaning performance. The results presented in this thesis can be implemented in the design of microfiber adhesives with robust adhesion, self-cleaning and anti-fouling characteristic, for use in numerous applications and in various environments.