Wide-bandwidth high-resolution search for extraterrestrial intelligence

Research accomplished during the third 6-month period is summarized. Research covered the following: dual-horn antenna performance; high electron mobility transistors (HEMT) low-noise amplifiers; downconverters; fast Fourier transform (FFT) array; and backend 'feature recognizer' array

Distribution, Elimination, and Biopersistence to 90 Days of a Systemically Introduced 30 nm Ceria-Engineered Nanomaterial in Rats

Nanoceria is used as a catalyst in diesel fuel, as an abrasive in printed circuit manufacture, and is being pursued as an antioxidant therapeutic. Our objective is to extend previous findings showing that there were no reductions of cerium in organs of the mononuclear phagocyte (reticuloendothelial) system up to 30 days after a single nanoscale ceria administration. An ~5% aqueous dispersion of citrate-stabilized 30 nm ceria, synthesized and characterized in-house, or vehicle, was iv infused into rats terminated 1, 7, 30, or 90 days later. Cageside observations were obtained daily, body weight weekly. Daily urinary and fecal cerium outputs were quantified for 2 weeks. Nine organs were weighed and samples collected from 14 tissues/organs/systems, blood and cerebrospinal fluid for cerium determination. Histology and oxidative stress were assessed. Less than 1% of the nanoceria was excreted in the first 2 weeks, 98% in feces. Body weight gain was initially impaired. Spleen weight was significantly increased in some ceria-treated groups, associated with abnormalities. Ceria was primarily retained in the spleen, liver, and bone marrow. There was little decrease of ceria in any tissue over the 90 days. Granulomas were observed in the liver. Time-dependent oxidative stress changes were seen in the liver and spleen. Nanoscale ceria was persistently retained by organs of the mononuclear phagocyte system, associated with adverse changes. The results support concern about the long-term fate and adverse effects of inert nanoscale metal oxides that distribute throughout the body, are persistently retained, and produce adverse changes

Meeting Report: Threats to Human Health and Environmental Sustainability in the Pacific Basin

The coastal zone of the Pacific Rim is home for about one-third of the world’s population. Disproportionate growth of Far Eastern economies has produced a disproportionate share of related environmental difficulties. As the region searches for acceptable compromises between growth and environmental quality, its influence on global environmental health is certain to increase. Consequences of global environmental change such as habitat alteration, storms, and sealevel rise will be particularly acute among Pacific Rim nations. Adverse health effects from arsenic exposure in Pacific Rim nations have been used to justify drinking water standards in the United States and elsewhere. As global manufacturing in the Pacific Rim increases, the centroid of global air quality and waste management issues will shift further toward Far Eastern nations. The Eleventh International Conference of the Pacific Basin Consortium (PBC) was held in September 2005 in Honolulu, Hawaii. The purpose of the conference was to bring together individuals to discuss regional challenges to sustainable growth. The historic emphasis of the conference on hazardous wastes in relation to human health makes the PBC an ideal forum for discussing technical aspects of sustainable economic growth in the Pacific region. That role is reflected in the 2005 PBC conference themes, which included management of arsenic in potable waters, air quality, climate change, pesticides, mercury, and electronics industry waste—each with emphasis on relationships to human health. Arsenic management exemplifies the manner in which the PBC can focus interdisciplinary discussion in a single technical area. The conference program provided talks on arsenic toxicology, treatment technologies, management of arsenic-bearing residuals from water treatment, and the probable societal costs and benefits of arsenic management

Versatile electrochemical coatings and surface layers from aqueous methanesulfonic acid

Ever tightening environmental pressure together with the continued need for coatings able to meet challenging service environments have stimulated advances in coating technology. In the case of electrochemical techniques, the classical techniques of electrodeposition and anodising are being upgraded to meet the need for modern surface engineering coatings (including nanostructured films) on metals. A major challenge is to retain conventional processing, including aqueous solutions, simple power supplies and existing electrolyte tanks while using cost effective, ‘green’ electrolytes. One successful direction has been the emergence of electrolytes based on methanesulfonic acid, MSA which has good electrolytic conductivity and is capable of dissolving many metals as well as acting as a useful medium for dispersion of solids prior to electrophoretic coating. A range of application methods result, including electroplating, anodising and electrophoretic deposition from a stable, aqueous sol. A diverse range of coating materials is emerging, including metals, alloys, porous metal oxide films, conductive polymers and many composites. This review illustrates the usefulness and applications of MSA electrolytes using recent examples from the authors' laboratories and others. Developing coatings, including alternating multilayers of Sn and Cu, nanostructured metals, hierarchical pores, nanotubular metal oxides and graphene composites are briefly considered. This is a review with 94 references

Copper electrodeposition from an acidic plating bath containing accelerating and inhibiting organic additives

Copper electrodeposition on copper from still plating solutions of different compositions was investi- gated utilising electrochemical impedance spectroscopy (EIS), cyclic voltammetry, and scanning electron microscopy (SEM). An acid copper sulphate plating base solution was employed either with or without sodium chloride in the presence of a single additive, either polyethylene glycol (PEG) or 3-mercapto-2- propanesulphonic acid (MPSA), and their mixture. Thallium underpotential deposition/anodic stripping was employed to determine the adsorption capability of additives on copper. In the absence of chloride ions, MPSA shows a moderate adsorption on copper, whereas PEG is slightly adsorbed. At low cathodic overpotentials, the simultaneous presence of MPSA and chloride ions accelerates copper electrodeposition through the formation of an MPSA-chloride ion complex in the solution, particularly for about 220 mM sodium chloride. The reverse effect occurs in PEG-sodium chloride plating solutions. In this case, from EIS data the formation of a film that interferes with copper electrodeposition can be inferred. At higher cathodic overpotentials, when copper electrodeposition is under mass transport control, the cathode coverage by a PEG-copper chloride-mediated film becomes either partially or completely detached as the concentration of chloride ions at the negatively charged copper surface diminishes. The copper cathode grain topography at the mm scale depends on the cathodic overpotential, plating solution composition and average current density. Available data about the solution constituents and their adsorption on copper make it possible to propose a likely complex mechanism to understand copper electrodeposition from these media, including the accelerating effect of MPSA and the dynamics of PEG-copper chloride complex adsorbate interfering with the surface mobility of depositing copper ad-ions/ad-atoms.Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA)Facultad de Ciencias Exacta

Copper electrodeposition in a deep eutectic solvent. First stages analysis considering Cu(I) stabilization in chloride media

The aim of the present work is to study copper electrocrystallization in a Deep Eutectic Solvent (DES) (eutectic mixture of choline chloride and urea 1:2) as electrolyte, paying special attention to the influence of the liquid on the nucleation mechanism. Deposition process was studied from both Cu(II) and Cu(I) solutions. As the DES solvent is chloride rich, a parallel analysis was made in aqueous solution containing an excess of chloride to compare medium influence on nucleation mechanism. While copper (I) can be directly electrodeposited from chloride excess solutions, copper (II) electrodeposition takes place via a separate step in which Cu(II) is firstly reduced to Cu(I). A methodology is proposed for studying mechanistic aspects of the early stages of copper electrodeposition from the Cu(II) chloride solutions. For all solutions, cyclic voltammetry was used to establish the potential range at which copper electrodeposition occurred, while potentiostatic technique was used to study the nucleation mechanism. In all media, deposition follows a nucleation and three-dimensional growth controlled by diffusion. The diffusion coefficient of Cu(I) species present in the solution has been calculated from potentiostatic curves by logarithmic linear regression of j vs t−1/2 at long deposition times, whereas the same parameter for copper (II) was calculated from cyclic voltammetry, taking advantage from the process quasi -reversibility. The viability of the nucleation mechanism by Scharifker-Hills model was demonstrated by the analysis of the rising part of the j-t transients independently of the selected solution

2.4 GHz Inkjet-printed RF Power Harvester on Bulk Cardboard Substrate

Inkjet-Printing Technology provides the ability of fabricating electronic circuits on different substrates such as: cardboard, wood, kapton and etc. The advantages of this technology are reduction in production cost in comparison to conventional laminate substrates and also being environmentally-friendly circuits which is one of the main goals in any manufacturing field. Having environmentally-friendly and low cost productions are possible by utilizing paper as the substrate and Inkjet-printing as the fabrication technology. In addition, reducing the power consumption in any circuit is an important factor in designing a circuit. In any wireless portable device, usage of battery causes a limitation in application space and decreases the lifetime of devices .Since increasing the lifetime of battery is still infeasible, power harvesting energy is one of the solutions in designing battery-less circuits. Power harvesting is a process by which energy is delivered by scavenging DC power from ambient sources. The ambient sources for power harvesting can be light, temperature, motion and electromagnetic in RF (Radio Frequency) range. Among all these sources, ambient RF energy, in both indoor and outdoor is generally available in all hours at different frequency bands. Hence RF energy harvesting is one the most popular type of power harvesting. The ambient RF sources are: Wi-Fi transceivers,AM/FM radio, television broadcasting, mobile networks and communication devices. In this Project, experimental investigations on the inkjet-printed RF power harvester for 2.4GHz are presented. An one stage discrete rectifier based on a voltage doubler structure and a planar monopole antenna are fabricated on cardboard using inkjet printing.The performance of the whole system is examined by measuring the output voltage of the RF power harvester. By the utilization of the proposed idea, the fabrication of low cost Environmental-friendly battery-less wireless modules is conceivabl

Operations Control Manual for Star Circuits Inc.

The research described in this thesis involves the documentation and economic analysis of the manufacturing process for making printed circuit boards at Star Circuits Inc., located in Brookings SD. It consists of three parts, the first is a procedural manual, the second is a quality assurance manual and the third is an analysis of the manufacturing cost of printed circuit boards. The procedural manual will be used within Star circuits Inc. to insure that uniform procedures are used in the manufacturing process. The procedural manual provides a standard by which to evaluate an employee\u27s performance on the job. The procedural manual provides a clear picture of what is happening to each printed circuit board as it progresses through the manufacturing process. This is important from the customer’s point of view to insure that quality is assured in each step of the manufacturing process. The procedural manual also provides a section in each procedure on safety and precautions that must be observed during manufacturing. Safety must be monitored and carefully controlled for the following reasons. The first is, to insure employees a safe place to work, free from unknown hazards that can cause injury. The second is to make employees aware of safe practices involved in each process. This in turn makes them aware of the proper procedure to follow at each step of manufacturing process. These concerns will also increase employee moral because they know the company is concerned about their safety and performance. The third is that as safety is emphasized and claims reduced a company will be rewarded by reduced insurance rates and therefore reduced overhead

Microfabrication processing of titanium for biomedical devices with reduced impact on the environment

This thesis presents research on a novel method of microfabrication of titanium (Ti) biomedical devices. The aim of the work was to develop a commercial process to fabricate Ti in a more environmentally friendly manner than current chemical etching techniques. The emphasis was placed on electrolytic etching, which enables the replacement of hazardous hydrofluoric acid-based etchants that are used by necessity when using Photochemical Machining (PCM) to produce intricate features in sheet Ti on a mass scale. Titanium is inherently difficult to etch (it is designed for its corrosion-resistant attributes) and as a result, Hydrofluoric acid (HF) is used in combination with a strong and durable mask to achieve selective etching. The use of HF introduces serious health and safety implications for those working with the process. The new technique introduces the use of a “sandwich structure”, comprising anode/insulator/cathode, directly in contact with each other and placed in an electrolytic etching cell. In this technique the same photolithography process is utilised to achieve selective etching on a metal substrate as in the PCM process. However, for the electrolytic etching stage, the inter- electrode gap (IEG) is reduced significantly from a few centimetres, as usually applied in electrochemical processes, to 4 μm. The intention behind this was to improve the current distribution experienced at the anode (Ti) during subsequent electrolytic etching. The sandwich structure was developed by deposition of a photoresist S1818 and Copper (Cu) on top of Ti. Firstly, a manual sanding of the substrate was applied in order to eliminate the oxide layers which could strongly affect a final electrolytic etching. The soft- and hard-bake stages involved in the processing of the S1818 resist were optimised to produce a stress-free Ti/S1818/Cu/S1818 structure. Ultimately a pattern would be imparted onto the S1818/Cu/S1818 that would ultimately be imparted through to the Ti layer during the last stage, electrolytic etching. In order to achieve this, a Cu electroless deposition was developed as a technique to obtain a conductive film which would act as a cathode during the electrolytic etching of the target, Ti layer. The results of the electrolytic etching of the Ti sandwich structure revealed flat-base profiles of half-etched (“half-etch” is the term used to signify an etch that does not penetrate completely through the thickness of the metal sheet) micro-holes in the Ti layer. The problem of delamination of the electroless Cu, in 10 % w/v HCl electrolyte used as an etchant, was solved by electroplating a 12 μm layer of Cu on top of the 60 nm Cu electroless deposited film. Using this technique, micro-features were achieved in Ti. The half-etched micro-holes were characterised to have an overall spherical shape corresponding to the imaged pattern and a preferred flat-base profiles (typically a raised land of material arises in conventional electrolytic etching). A series of parameters were tested in order to control the process of electrolytic etching through the Ti sandwich structure by measuring etch rate, surface roughness of the etched pattern and the etch factor. The applied current densities (CD) of 10, 15, 20, and 25 A/cm2 showed proportional dissolution to the applied current. Electrolytic etching with a CD of 20 A/cm2 demonstrated a high etch rate of 40 μm/min. and a relatively low Ra of 2.8 μm, therefore, it was utilised in further experimental work. The highest etch rate of 50 μm/min. and an improved distribution of half-etched micro-holes was achieved by the introduction of 4 crocodile connectors (2 per electrode) and mechanically stirring of the electrolyte (800 rpm) while performing the electrolytic etching. The maximum etch depth of 143.9 μm was produced in Ti when the electrolytic etching was performed at the same conditions for 3 minutes. The incorporation of ultrasonic agitation to the electrolytic etching and an electrolyte temperature of 130 C resulted in a decrease of the surface roughness of the etched micro-holes to 0.5 μm. The results of the Ti sandwich structure electrolytic etching proved the concept of minimising the IEG in order to obtain a uniform Ti dissolution on a feature scale, improved control of the electrolytic dissolution over the whole area of the sample with utilisation of the lower hazard etchant at the same time