Flip chips and acoustic micro imaging: An overview of past applications, present status, and roadmap for the future

Acoustic Micro Imaging has been used over the past years to successfully evaluate the quality of flip chip underfill and interconnect bonds. Flip chip technology is steadily progressing toward smaller devices and higher IO count which leads to smaller bumps and bonds. In many instances the small bumps are in close proximity to the edge of a relatively thick silicon chip which leads to information being obscured by edge effects. This is driving AMI technology to provide higher resolution images with improved clarity of information at the edges in order to evaluate the devices. This paper will present an overview of AMI flip chip applications from the inception to the present and include a roadmap for future AMI developments to meet the challenges presented by changes in the design and manufacturing of flip chips.     

The reaction of kaolin with fluorides: I. Effect of neutral and acid sodium fluoride solutions

The reaction between kaolinite and neutral and acid sodium fluoride solutions was investigated at different temperatures and over the acid pH range. The stoicheiometric replacement of hydroxyls in the kaolinite crystal lattice by fluoride ions, as reported by earlier workers, was not confirmed. The release of hydroxyl ions into solution was due predominantly to the disruption of the kaolinite crystal lattice. In the presence of sodium ions and at pH < 7, sodium fluoro-silicate and cryolite were found as solid phases. At pH > 7, only cryolite was found as a solid phase. Small, spherical, particles were observed in all cases. These particles were believed to be amorphous silica, formed as an intermediate phase in the disruption process.     

Modeling Biofilms on Gas-Permeable Supports: Flux Limitations

A computer model is used to investigate the microbial uptake of oxygen and a carbon-source substrate for biofilms growing on gas-permeable, hollow-fiber membranes and impermeable solid supports of similar geometry. Substrate and oxygen fluxes are predicted for different biofilm thicknesses as a function of fluid velocity and substrate concentration. Under conditions of oxygen limitation, low water velocities, and moderate to high bulk liquid substrate concentration, the membranes have a clear advantage and outperform solid supports. This improvement in performance stems from the ability of the membrane to deliver high oxygen concentrations (8–20 mg∕L) directly to the biofilm, whereas it is difficult to maintain bulk dissolved oxygen concentrations much above 4 mg∕L in wastewater treatment. The growth of an active biofilm can actually increase the flux of oxygen across the membrane dramatically; however, the presence of a biofilm always reduces the ability of a membrane to oxygenate the surrounding wastewater. This drop in oxygen transfer performance is caused by the fact that the active biofilm consumes oxygen and impedes diffusion of the oxygen into the bulk water. In thick biofilms the oxygen flux can drop to zero so that the external regions of the biofilm and the external wastewater become anaerobic. This may cause some operating problems, but it may also facilitate nitrification-denitrification. Additional aeration of the external wastewater could improve biofilm performance and assist in controlling biofilm growth.     

The Value of Cittaslow as an Approach to Local Sustainable Development: A New Zealand Perspective

Cittaslow is an Italian-inspired global network of towns that collectively resist globalization and mainstream corporate-centred development through planning and urban design that prioritize each town's local, unique and historic resources. Internationally, Cittaslow's regulations-for-action approach has assisted towns to more effectively implement sustainable development principles. This paper presents research from three New Zealand case-study towns, to assess the potential application of Cittaslow principles to aid sustainable development and economic growth in small towns. The findings revealed that planners and community members generally perceived Cittaslow as a superfluous ‘brand’ that imposed additional unnecessary regulations and an approach that lacked general community support.     

Comparison of treatment of mastitis by oxytocin or antibiotics following detection according to changes in milk electrical conductivity prior to visible signs

Mastitis was induced in dairy cows by infusion of 500 cfu of Streptococcus uberis into the mammary gland. Most infections developed to clinical disease, and the majority were predicted by changes in the electrical conductivity of the foremilk. The benefits of clinical prognosis and bacteriological cure were determined for cases that were treated when predicted to develop into clinical mastitis and compared with cases that were allowed to develop until milk clotted or until pyrexia before intramammary antibiotic treatment was used. Treatment prior to clinical mastitis included use of intramammary antibiotic or intramuscular oxytocin to allow stripping of residual milk to remove bacteria. All infections in which treatment was delayed resulted in clinical mastitis that was cured clinically and bacteriologically by sustained treatment using a broad-spectrum intramammary antibiotic preparation once daily but requiring a mean treatment time of 10 d. It was possible to prevent clinical mastitis from developing and to eliminate all infections in cows that were treated early when the developing disease was predicted by changes in the electrical conductivity of quarter foremilk and was treated aggressively by administering an intramammary antibiotic at each milking for 3 d. Treatment of 20 IU of oxytocin at six successive milkings of cows that were predicted to develop disease eliminated 25% of the infections, but 75% of the cows developed clinical mastitis. Those cases were resolved by sustained daily treatment using the same intramammary antibiotic. Elimination (100% clinical and bacteriological cure) of all infections caused by Strep. uberis was possible with early and aggressive or sustained use of the intramammary antibiotic. The early intervention using an intramammary antibiotic, when infection was first indicated by changes in the electrical conductivity of milk, was the most efficient method to achieve cure and led to quicker recovery of milk quality to a saleable standard.     

Stimulating In Situ Hydrogenotrophic Denitrification with Membrane-Delivered Hydrogen under Passive and Pumped Groundwater Conditions

A technology was developed to stimulate autotrophic biological denitrification by supplying hydrogen (H2) to groundwater via gas-permeable membranes. The purpose of this project was to investigate this technology at field scale, determining whether it could be successfully scaled up from the laboratory. The field site was located in Becker, Minnesota and contained high levels of NO3? (22.8±2.0?mg/L-N) and dissolved oxygen (DO) (7±1?mg/L). Membranes installed in groundwater wells were successful in delivering H2 to the groundwater over the two-year operating period. Hydrogen stimulated microbial reduction of DO and NO3?, degrading up to 6 mg/L DO and converting up to 10.0 mg/L NO3?-N to NO2?-N when operated passively. When recirculation pumps were installed performance in the field did not improve significantly because of mixing with more oxygenated water. However, complementary modeling studies showed that complete DO reduction and denitrification to N2 was possible but the zone of influence and total H2 demand were limiting factors. Water was recirculated in the field from downgradient to upgradient membrane-containing wells to increase the H2 delivery through the membrane by an increase in water velocity. The depth to groundwater ( ～ 13.7?m) caused some water reoxygenation during recirculation, which may preclude the use of this technology at deep sites, as this makes it more difficult to install sufficient wells and control recirculation.     

Use of graph theory measures to identify errors in record linkage

Ensuring high linkage quality is important in many record linkage applications. Current methods for ensuring quality are manual and resource intensive. This paper seeks to determine the effectiveness of graph theory techniques in identifying record linkage errors. A range of graph theory techniques was applied to two linked datasets, with known truth sets. The ability of graph theory techniques to identify groups containing errors was compared to a widely used threshold setting technique. This methodology shows promise; however, further investigations into graph theory techniques are required. The development of more efficient and effective methods of improving linkage quality will result in higher quality datasets that can be delivered to researchers in shorter timeframes.     

An evaluation of pretreated natural zeolites for ammonium removal

Clinoptilolite has been widely studied for ammonium removal in the past 2 yr. However, many investigators have reported variations in the measured capacities of samples of clinoptilolite. These studies and the factors believed to influence measured zeolite capacity are reviewed. In addition no studies to evaluate other natural zeolites for ammonium removal have been reported.In this study samples of clinoptilolite, erionite, mordenite and phillipsite provided by the Anaconda Company were evaluated for ammonium removal from wastewaters. In addition, samples of clinoptilolite were pretreated in various ways to determine whether an improvement in ammonium removal performance could be realized. Total exchange capacities, capacities for ammonium removal from a synthetic waste, packed bed densities and crushing strengths were measured.Phillipsite was found to have almost twice the weight capacity for ammonium removal from synthetic waste compared to that of clinoptilolite. The volumetric capacity was 26% better than that of clinoptilolite. However, the phillipsite sample was extremely friable and it could not be used for water treatment unless it was strengthened with a binder.Pretreatment of clinoptilolite with NaOH, HNO₃ and steam did little to improve the zeolite's performance. However, heat pretreatment (600°C for 1 h) improved the zeolite's selectivity for ammonium significantly. Ammonium removal capacities were increased by approximately 17% for heat treated zeolite samples although the total exchange capacity of the zeolite was reduced somewhat.