<p>Interception av snö eller regn på trädkronor är en viktig del av det hydrologiska kretsloppet. Upp till en tredjedel av all snö som faller över skogsområden når aldrig marken på grund av stora avdunstningsförluster av interceptionsförrådet, vilket minskar vårflöden i älvar. Goda prognoser av dessa flöden är viktiga för vattenkraftsindustrin. För att kunna förbättra modeller, i vilka interceptions-avdunstningsprocessen ingår, krävs lämpliga mätmetoder för interceptionförrådet av snö. Syftet med detta arbete var att undersöka om impulsradarutrustning kan användas för att mäta interceptionsförrådet av snö på barrträd. Metoden bygger på att mäta hastigheten och utsläckningen hos en elektromagnetisk impulsvåg, vilken skickas från en sändarantenn genom ett avsnitt skog till en mottagarantenn. Både utsläckningen och hastigheten påverkas av snö och vatten på trädens kronor, och kan med så kallade blandningsformler relateras till mängd vatten. Blandningsformler beskriver de elektromagnetiska egenskaperna hos heterogena material. Laboratorietester visade att interception av flytande vatten på små trädkronor gav upphov till förändringar av impulsvågens hastighet och utsläckning mätbara med radarutrustningen. Uppskattningar av mängden intercepterat vatten från radarmätningarna gav en överskattning jämfört med oberoende referensmätningar, däremot stämde relativa variationer väl överens mellan mätningarna. Tydliga samband mellan impulsvågens utsläckning och mängden intercepterat vatten kunde inte bestämmas från experimenten. Utsläckningsresultaten var svårtolkade och lämpliga blandningsformler hittades inte i litteraturen. Metoden testades även en vecka i fält i norra Sverige. Trots att installationen inte var den bästa visade resultaten ändå god överensstämmelse mellan uppskattade förändringar av interceptionsförrådet från radarmätningarna, och observerade väderförändringar samt oberoende referensmätningar med en trädvågsanordning. Resultaten tyder på att metoden kan ge goda uppskattningar av interceptionsförrådet, då en väl fungerande installation av utrustningen används och efter att vidare kalibreringsförsök genomförts.</p> / <p>Interception of rain or snow in forest canopies is an important component of the hydrological cycle. Up to one third of the total winter precipitation never reaches the ground in forest areas due to evaporation losses of intercepted snow, which reduces spring-time water flow in rivers. Accurate spring flow predictions are important for the hydro-power industry. Appropriate measurement methods of intercepted snow are needed in order to improve models involving the interception evaporation process. The aim of this study was to explore the possibilities of an impulse radar system to measure the snow interception storage on coniferous trees. The method is based on measurements of the velocity and attenuation of an electromagnetic impulse wave, generated in a transmitting antenna and sent through a forest section and detected by a receiving antenna. The attenuation and velocity is affected by ice and water in the canopy air space, and can be related to amounts of water using so-called mixing formulas that describe the average electromagnetic properties of heterogeneous materials. Controlled laboratory measurements on small canopies showed that interception of liquid water was well above the detectable limits of the radar system, with respect to both attenuation and velocity changes. Estimations of the mass of intercepted water based on velocity changes overestimated the reference measurements, but relative variations were well captured. No clear relation could be found between amount of water on canopies and impulse wave attenuation from the experiments. The attenuation results were difficult to interpret, and appropriate mixing formulas were not found in the literature. The method was further tested for one week under field conditions in northern Sweden. In spite of a non-optimal equipment installation results of estimated changes of the interception storage showed a good agreement with observed weather variations and reference measurements using a tree weighing device. The method can have good conditions to give correct estimations of the snow interception storage, using appropriate installation and further calibration measurements.</p>

Approved for public release, distribution is unlimited. / Ground penetrating radars (GPRs), also known as subsurface radars, are used in many applications including detection of land mines and unexploded ordnance (UXO). Despite significant long-term investment in GPRs for mine and UXO detection, it remains true that no GPR system that meets operational requirements has yet been fielded; however, recent advances in several mine detection radars under development have produced significant improvements in detection performance and false-alarm mitigation over what was achievable only a few years ago. This research examines the suitability of modeling helical antennas to achieve a broadband characteristic for GPR implementation. Although the two-arm counter-wound helix provides the required spot illumination, it is expected that more arms may have to be added to reduce the radiation in the back direction and to match the input impedance to the feed line. Microwave Design Studio (MDS) has been used extensively to simulate the broadband characteristics of the helical antenna. An overall design strategy is outlined, together with a more detailed treatment of the ground penetrating radar subsystems and topics that are relevant to effective subsurface radar operation. These include soil characterization, the choice of the frequency of operation, as well as the design and construction of suitable helical antennas. Finally, a new antenna structure called the counter-wound quadrifilar helical antenna (CQHA), which is suitable for subsurface radar applications, is examined. The counter-wound quadrifilar helical antenna has a broad bandwidth and a linear polarization with a controllable plane of polarization from a planar geometry. / Major, Republic of Singapore Air Force

As sea level rises, saltwater migration can threaten coastal ecosystems and beach-dune environments, which negatively impacts coastal flora. This study uses ground penetrating radar (GPR) to evaluate the spatiotemporal variability of saltwater migration in the near shore at high lateral resolution (i.e. cm) by using daily micro tidal cycles as analogs to infer saltwater migration. Time-lapse GPR profiles were collected at low and high tide capturing phase lags of the tidal flux through different substrates. GPR measurements were collected at two sites in Miami with contrasting lithologies: a) Crandon Park, composed of unconsolidated sand; and b) the Barnacle Historic State Park, composed of the Miami Limestone Formation. Laboratory-scale GPR measurements were collected over samples mimicking field conditions. The results may be helpful to identify regions vulnerable to saltwater migration in the near shore based on lithological variability, and to mitigate negative impacts for flora in beach-dune habitats during sea level rise. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2019. / FAU Electronic Theses and Dissertations Collection

Thesis (M.S)--West Virginia University, 2007. / Title from document title page. Document formatted into pages; contains xi, 104 p. : ill. (some col.). Vita. Includes abstract. Includes bibliographical references (p. 69-70).

Thesis (M.S.)--West Virginia University, 2006. / Title from document title page. Document formatted into pages; contains x, 100 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 83-86).

The plasma membrane functions as a barrier, restricting entry of hydrophilic pharmaceutical agents. Cell-penetrating peptides (CPPs) are capable of transporting bioactive cargos into the cell and have consequently been extensively investigated for their mechanism of entry and capability to deliver various cargos spanning from peptides to plasmids. The main aim of this thesis was to investigate the mechanism and capability of some of these CPPs to deliver mainly oligonucleotides and peptides into the cell. Oligonucleotides in the form of ds DNA decoy for sequestering of transcription factors or PNAs for redirection of splicing. In addition, peptides derived from the interaction interface of a tumor suppressor protein were investigated for their potential to combine a biological effect with internalization. Peptides with or without any cargo were predominantly dependent on some form of endocytic mechanism for internalization, substantiated by using a functional assay, where all tested CPPs were associated with endocytosis for delivery of splice correcting PNAs. A new CPP, M918 proved most efficient in promoting splice correction and internalized mainly via macropinocytosis. In addition, TP10 efficiently delivered dsDNA decoy oligonucleotides for sequestering of the transcription factor Myc with a concomitant biological response, i.e. reduced proliferation. Finally, for the first time, to our knowledge, a novel pro-apoptotic peptide with cell-penetrating properties was designed from the tumor suppressor p14ARF, which decreased proliferation and induced apoptosis in cancer cell-lines, potentially mimicking the full-length protein. Altogether, this thesis highlights the functionality of CPPs and the possibility to develop new CPPs with improved or new properties, having the potential to advance delivery of therapeutic compounds.

High molecular weight biomolecules are becoming important in the development of new therapeutics. However, their size and nature creates a major limitation for their application – poor penetration through biological membranes. A new class of peptides, cell-penetrating peptides (CPPs), has shown the capability to transport various macromolecules inside the cells. However, there are at least two limiting factors for successful application of CPPs: the lack of cell-type specificity and restricted bioavailability resulting from endocytic uptake of CPPs and entrapment in endosomal compartments. This thesis aims at designing delivery vehicles for therapeutic substances. In papers I-III, the CPPs have been rationally modified in order to achieve in vivo selectivity towards cancer cells. The first two papers employ tumor homing peptides as targeting moieties coupled to the N-termini of CPPs. In the third paper, a CPP is C-terminally prolonged with a matrix metalloproteinase 2 (MMP-2) specific cleavage site followed by an inactivating amino acid sequence. In tissues overexpressing MMP-2, i. e. in proximity to cancer, the CPP is activated after proteolytic removal of the inactivating sequence, thus the cargo can be transported inside the cells. In paper IV, several CPPs have been N-terminally modified with a stearyl moiety and applied for the delivery of splice-correcting oligonucleotides. We show that stearyl-TP10 is as effective in oligonucleotide delivery as Lipofectamine™ 2000. Moreover, stearyl-TP10 has preserved efficacy in serum and is not toxic to cells. In conclusion, the rational modifications of CPPs greatly potentiate their application in cargo delivery both in vitro and in vivo.

This thesis reports on the investigations of resistive-capacitive (RC) loaded bow-tie antennas with special emphasis on impulse ground penetrating radar applications. Impulse radiation for ground penetrating radar is a challenging research topic because of the unique problem arising from impulse radiation: late-time ringing, which usually masks the important echo signals from the targets. While resistive loading is a common solution for eliminating late-time ringing, use of resistive loading typically sacrifices the radiation efficiency. In this thesis, a resistive-capacitive loading technique is investigated for a circular bow-tie antenna in the attempt to reduce/suppress the late-time ringing as well as to maintain a relatively high radiation efficiency. To implement the system, a microstrip differentiator, which converts a monopulse into a Gaussian-like monocycle to be used as input impulse, is presented. Further, specially designed coplanar waveguide/coplanar strip (CPW/CPS) baluns embedded with Chebyshev transformers of characteristic impedance up to 120 have been constructed and tested. To evaluate the system, instead of using the conventional peak voltage value of the radiated waveform, average radiated energy, average ringing energy, relative radiation efficiency and relative ringing efficiency are utilized and these metrics are easily established using low-cost low-sensitivity probes. Measurement results show that the RC-loading scheme is functioning as expected and the impulse system as a whole is capable of reducing the late-time ringing energy to 50% while maintaining average radiation energy as 83% when compared with capacitive loading cases. / October 2006

The goal of this research project is to identify the efficacy of the ground penetrating radar (GPR) technique in locating underground coal mine related subsidence features at Malakoff and Bastrop, Texas. The work at Malakoff has been done in collaboration with the Railroad Commission of Texas (RRC). RRC has been carrying out reclamation of abandoned underground coal mines at Malakoff since the early 1990’s. The history of the specific mining operations (at Malakoff and Bastrop) that took place in the early 1900’s has been difficult to ascertain; therefore, the use of a geophysical techniques like ground penetrating radar to identify hidden voids and potential subsidence features is vital for future reclamation process. Some of the underground mine workings at the field site have collapsed over time affecting the topography by creating sinkholes. GPR data, employing 25 MHz, 50 MHz and 100 MHz frequency antennae, have been collected in common offset patterns and azimuthal pattern. GPR data indicate the mine tunnels possibly connecting existing sinkholes by radargram hyperbolae that correspond with mine openings observed visually or during reclamation. This study also denotes the importance of understanding the variable physical properties of the stratigraphy, which could lead to false alarms by misinterpretation of the radar signals. Natural and man-made above-ground structures cause obstructions in data collection, and hence an optimal design is required for each survey. RRC successfully ground-truthed the data during its reclamation process. In turn, the acquired geophysical data helped to guide the reclamation. At Bastrop, GPR data along with historical documentation led to the conclusion that coal mining did exist in this region but is not a major concern to the immediate stability and safety of the field site. It can be concluded from both the studies that the GPR technique identifies anomalous shafts/tunnels possibly connecting potential failure.

Thesis (Ph. D.)--University of Texas at Austin, 1999. / Vita. Includes bibliographical references (leaves 91-95). Available also in a digital version from Dissertation Abstracts.