Along with the general requirement of continuously increasing efficiency of hydrostatic drivetrains, variable displacement machines are of major concern in research and development. To this effect, the whole machine performance is mainly dependent of the displacement variation system (DVS) performance. A lot of work to this topic focusses on the controller and actuator level. The aim of this paper is to offer a more fundamental view on DVS by giving a focus to the basic hydro-mechanical principles.

Measures of individualization and integration offer a great potential for further development and optimization in hydraulic drive technology. Advantages are seen especially for energy efficiency and functionality. These potentials motivate current research activities for displacement controlled systems and for valve controlled structures. For the latter, the focus lies on strategies of independent metering. Furthermore, expected challenges for the future are discussed.

The floating cup principle is a general hydrostatic principle for both constant and variable displacement pumps and motors, as well as for hydraulic transformers. In this paper, the focus will be entirely on the control of the displacement of the variable 28 cc Floating Cup pump (FCVP28). The floating cup principle features two opposed swash plates, for which both angular positions need to be controlled in order to cover the entire range from zero to full displacement. The results of both extended numerical analysis as well as simplified linearized models will be compared to test results on a 28 cc FCVP. Special emphasis will be on the dynamic behaviour of the displacement control.

Environmental awareness, production costs and operating expenses have provided a large incentive for the investigation of novel and more efficient fluid power technologies for decades. In the earth-moving sector, hydraulic hybrids have emerged as a highly efficient and affordable choice for the next generation hydraulic systems. Displacementcontrolled (DC) actuation has demonstrated that, when coupled with hydraulic hybrids, the engine power can be downsized by up to 50% leading to substantial savings. This concept has been realized by the authors‘ group on an excavator prototype where a secondary-controlled hydraulic hybrid drive was implemented on the swing. Actuatorlevel controls have been formulated by the authors‘ group but the challenge remains to effectively manage the system on the supervisory-level. In this paper, a power management controller is proposed to minimize fuel consumption while taking into account performance. The algorithm, a feedforward and cost-function combination considers operator commands, the DC actuators‘ power consumption and the power available from the engine and hydraulic hybrid as metrics. The developed strategy brings the technology closer to the predicted savings while achieving superior operability.

Liebherr mobile harbor cranes use electrical generators to provide electrical power for load attachment devices such as container spreaders or magnets. Upcoming exhaust and noise emission standards and energy saving considerations lead to a broad diesel engine speed range. The challenging design aspect is to ensure a constant speed of the asynchronous generator by the hydraulic drive system. In addition, electrical load profiles of inductive consumers usually have DT1 system characteristics with very small time constants. They evoke fast torque variations interfacing the hydraulic transmission. Liebherr mobile harbor cranes, see Figure 1, usually have a closed hydraulic circuit containing a hydraulic pump with a high displacement volume that is adjusted electronically in accordance to the current diesel engine speed. Regarding the energy saving aspects, a further minimization of the diesel engine speed leads to a larger pump size with increasing torque losses. Depending on the pressure setting, the volume flows can be reduced in constant pressure grids. Especially in part-load operation this results in better efficiency compared to closed hydraulic circuits by minimizing the displacement volume of hydraulic components. To obtain a stable generator speed, it is essential to adjust the displacement volume of the hydraulic unit for equalizing its input torque with the Figure 1: LHM 800 Group 10 - Mobile Hydraulics | Paper 10-5 199 generator load torque. In interaction with the software-based control architecture, the stability of the electrical frequency depends on the mass inertia of the generator drive and time constants of the embedded hydraulic actuators. The system model, represented by ODEs is established and verified with a hydraulic simulation software. On that basis, the design approach of a PI-state-controller is presented. Corresponding controller gains and state feedback parameters are determined by pole placement techniques. To conclude this investigation a comparison between the hydraulically closed circuit and the constant pressure grid is shown by simulation and measurement data.

Learning and experience shape mate preferences in many species. My thesis investigates the role of experience on mating behavior of male and female sailfin mollies (Poecilia latipinna). In the first chapter I explore whether adult experience influences male sailfin molly mate preference for their sexual parasite, the Amazon molly (Poecilia formosa), and whether experience could account for reproductive character displacement (RCD) of male mate preference in this species. Sailfin males from sympatric populations show a stronger preference for conspecific females over Amazon mollies than do males from allopatric populations. I exposed males from sympatric and allopatric populations to either a sailfin female or an Amazon prior to a mating trial with an Amazon. For the allopatric population, males with recent experience with an Amazon directed fewer mating behaviors towards an Amazon during mating trials than did males with recent experience with a sailfin. Males from the sympatric population, however, performed the same amount of mating behaviors towards an Amazon regardless of experience. Thus adult experience influences mating preferences and suggests that experience may play a role in RCD in this species. In the second chapter I investigate whether a learned sensory bias could influence female mate preferences. Sensory biases that influence mate preferences can arise through selection on the sensory system in foraging and predator detection domains. I tested whether a learned preference originating outside of the mating domain, specifically a color-based food preference, can be transferred to a color-based preference for a male trait. I trained female sailfin mollies to associate either green or blue with food and then tested their preference for animated male sailfins featuring either a blue or green spot. I found that females did not prefer the male with the same color spot to which they had been conditioned. I discuss the problem of learned preference transfer and suggest directions for future research into the role of learning in sensory bias. / text

This report examines how the neighborhoods along the Metro Blue line have changed over the past two decades, and reflects on the current emerging issue in Transit oriented development (TOD), which is promoting equitable transit neighborhoods. The primary study area includes the route of the Metro Blue line through Los Angeles County where the most economically disadvantaged and marginalized communities are located in the county. In order to investigate the impact of the rail line effectively, the concept of Walksheds are used as the units of analysis, which is defined as the area within a half-mile walking distance from the transit station. Focusing on social equity impact of the transit system operation, the comparison analysis between Los Angeles County and the twenty-two Walksheds of each station in the line evaluates the changes in the close-by neighborhoods while also looking at various social demographic indicators that can reflect demographic shifts using decennial Census data of 1990, 2000, and 2010. While looking at the change through time series data analysis vertically, the performance of each station area is examined horizontally. Therefore, comparative analysis is conducted in four stages to figure out the extent to which the neighborhoods have changed, how rapidly the change occurred and whether the neighborhood change occurred in a positive way or not. The result from the four comparative analyses indicates that the Metro Blue line did not work as a catalyst for promoting economic opportunity in the region in spite of the initial expectations of its advocates. In the beginning of the rail operation of 1990, the neighborhoods along the rail line were excluded and poverty was widespread in the region. However, even after two decades, the twenty-two Walksheds along the Metro Blue Line still remain as undesirable places to live and marginalized as compared to the rest of the county. Moreover, the neighborhood change in the twenty-two Walksheds is negatively linked to the Walksheds based on the result of the comparative analysis. / text

Dysarthria is one of the most common signs of speech impairment in the cerebral palsy (CP) population. Facilitating strategies for speech enhancement in this population often include training on speech breathing. Treatment efficacy studies with cross-system measures in this population are needed for improved understanding and management of the interrelationship between respiratory, phonatory, and articulatory systems. The purpose of this study was to investigate the effect of breath group control on the coordination of articulatory and phonatory muscles and the acoustic measures related to speech and voice quality. A simultaneous acoustic, electroglottographic (EGG), and marker-based facial tracking recording system was employed to monitor the speech production behaviors of four adults with CP and 16 neurologically healthy controls. Subjects were instructed to perform three tasks, each containing speech targets with a voiceless plosive (/p/, /t/, or /k/) preceding a vowel (/i/, /a/, /u/, or /ɔ/). Task 1 consisted of a short reading passage embedded with target vowels without cueing from breath group markers. Task 2 included reading a series of monosyllabic and 3-syllable or 5-syllable non-speech words with the speech targets. Task 3 included reading the same short passage from Task 1 with cueing from breath group markers separating the passage into phrases with no more than five syllables per phrase. Measures from the acoustic, EGG and facial tracking recordings of the first and last syllable of all syllable trains produced in the non-speech task and the target vowels in the passage reading task were examined. Acoustic measures included voice onset time (VOT), vowel duration, fundamental frequency (F0), percent jitter (%jitter), percent shimmer (%shimmer), signal-to-noise ratio (SNR), and frequencies of Formants one and two (F1 and F2). EGG measures included speed quotient (SQ) and open quotient (OQ). Facial tracking measures consisted of maximum jaw displacement. Individual and averaged data were submitted to a series of two-way Analysis of Variances (ANOVAs) or two-way Repeated Measures ANOVAs to determine the effects of the relative position of an utterance in the breath group and the place of articulation of the consonants involved. In addition, mean vowel spaces derived from all three tasks were examined. Results revealed significant changes of VOT, F1, F2, SNR and SQ as a function of position. Significant changes of VOT, vowel duration, F2, F0, %jitter, %shimmer, and maximum jaw displacement as a function of place of articulation were also evident. In particular, breath group control was found to result in expansion of vowel space, especially for individuals with CP. These findings suggest that proper phrasing enhances articulatory and phonatory stability, providing empirical evidences in support of its usage in treating individuals with CP.

This dissertation explores the lasting effects of recurrent temporary medical humanitarian operations through ethnographic research in communities, clinical facilities, nongovernmental aid organizations, and governmental bureaucracies in the northern Somali Region of Ethiopia. First, I found that medical humanitarian aid has altered persons' subjective experiences and expectations of biomedicine, spirit possession, health, and healing. Popular health cultures and conceptions of "biomedicine" as well as "traditional medicine" were changing, in part due to repeated exposures to relief operations. Second, I documented novel social formations to cope with recurrent aid: new labor relations to enable temporary work with international NGOs; new medical migrations to access comparable care and foreign medical commodities at distant private hospitals; and transnational extra-legal economies of medicine to fill gaps in care. Third, a set of racialized narratives have emerged in the interstices of aid that warn of malpractice and abuse by non-Somali Ethiopian clinicians. Such discourses echo Somalis' historical experiences of ethnic-based conflict with Ethiopian groups as well as their contemporary marginalization from Ethiopian sources of power. Accordingly, although aid is designed to improve immediate access to basic healthcare and medications, I find it also exacerbated medical insecurity. Northern Somalis' discursive expressions of medical insecurity have increased, paradoxically alongside steady improvements in their health and nutrition indicators. Finally, health and humanitarian interventions have altered local notions and practices of citizenship. In the last ten years, as Ethiopia has decentralized its health care delivery system, aid has been progressively channeled through Somali Regional State institutions. Accordingly, many Somalis now discuss the diverse ways in which they are increasingly interpolated into regional politics-often in opposition to the Ethiopian government. Medical humanitarian aid has shaped expectations of government as well as biomedicine. I argue that these new forms of citizenship have emerged primarily because of the intimate and profound nature of medical encounters themselves. The narrow humanitarian mission to minister to what social theorists call the "bare life" of victims, in actuality, is neither dispassionate nor removed from sociality and politics. Medical aid potentially provides spaces in which relations of care-giving, trust, and therefore responsive governance structures can develop.

Migration and the concomitant crossing of borders is a growing world wide theme in literature. This phenomenon can be attributed to growing mobility and globalisation which allow people to move freely across national borders. Mobility is a key concept for the 21st century and can be used as an umbrella term for the crossing of borders and migration, also connecting with concepts such as displacement, diaspora, nomad, travel, exile and (post)colonialism. Migration as demographic phenomenon does not only include the borders of countries but also social, cultural, psychological and language borders. Memory as border can be added to this since it acts as a link between time and space. The crossing of (national) borders also holds certain consequences, amongst others the problem of origin and identity, outsidership and/or marginalization as well as the experience of loss. Two novels which can be classified as migrant literature – Idil, een meisje (Yasmine Allas) and De reis van de lege flessen (Kader Abdolah), and one novel which explores the problem of migration thematically – Anderkant die stilte (André P. Brink) – are analysed in this dissertation. Idil, een meisje (Yasmine Allas) portrays a female perspective by a female migrant writer, while De reis van de lege flessen (Kader Abdolah) offers a male perspective by a male migrant writer. Anderkant die stilte (André P. Brink) adds an additional dimension to gender analysis since a female perspective is portrayed by a male writer. These three novels, one from Afrikaans and two from Dutch literature, will be analysed to determine the manifestation of migration and displacement and the outcome(s) thereof with emphasis on gendered experience in these literature texts. / Thesis (MA (Afrikaans en Nederlands))--North-West University, Vaal Triangle Campus, 2013