Processing and aging characteristics of eutectic Sn-3.5Ag solder reinforced with mechanically incorporated Ni particles

Composite solders offer improved properties compared to non-composite solders. Ni reinforced composite solder was prepared by mechanically dispersing 15 vol.% of Ni particles into eutectic Sn-3.5Ag solder paste. The average size of the Ni particle reinforcements was approximately 5 microns. The morphology, size and distribution of the reinforcing phase were characterized metallographically. Solid-state isothermal aging study was performed on small realistic size solder joints to study the formation and growth of the intermetallic (IM) layers at Ni reinforcement/solder and Cu substrate/solder interfaces. Effects of reflow on microstructure and solderability, were studied using Cu substrates. Regarding solderability, the wetting angle of multiple reflowed Ni reinforced composite solder was compared to the solder matrix alloy, eutectic Sn-3.5Ag. General findings of this study revealed that Ni particle reinforced composite solder has comparable wetting characteristics to eutectic Sn-3.5Ag solder. Significant IM layers growth was observed in the Ni composite solder joint under isothermal aging at 150 C. Microstructural evolution was insignificant when aging temperature was lower than 100 C. Multiple reflow did not significantly change the microstructure in Ni composite solder joint.     

Analysis of cleavage fracture potential of martensitic stainless steel fusion structures: Part II. Fracture analysis procedures for flawed fusion structures

The potential for brittle cleavage fracture is a major concern for martensitic stainless steels which are candidates for fusion reactor structural materials. This study attempts to identify for flawed fusion structures the pertinent fracture resistance or failure parameters and the relationships between these parameters and the basic materials properties which govern cleavage fracture. Several procedures for relating test data to failure prediction, including Charpy-V-notch transition temperature referencing and two-parameter interpolation procedures, are considered; and results are discussed with respect to possible research paths for martensitic stainless steel alloy development.     

Subclinical Cushing's syndrome due to adrenal myelolipoma

We describe a patient with an incidental adrenal myelolipoma associated with biochemical evidence of Cushing's syndrome who lacked the physical stigmata of cortisol excess (subclinical Cushing's syndrome). Pathologic examination revealed the presence of adrenocortical cells mixed with myelolipomatous tissue. Although cases of clinically evident Cushing's syndrome due to adrenal myelolipomas have been reported previously, to our knowledge this is the first report associating adrenal myelolipoma and subclinical Cushing's syndrome.     

Design and operation of the wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source

The wide angular-range chopper spectrometer ARCS at the Spallation Neutron Source (SNS) is optimized to provide a high neutron flux at the sample position with a large solid angle of detector coverage. The instrument incorporates modern neutron instrumentation, such as an elliptically focused neutron guide, high speed magnetic bearing choppers, and a massive array of (3)He linear position sensitive detectors. Novel features of the spectrometer include the use of a large gate valve between the sample and detector vacuum chambers and the placement of the detectors within the vacuum, both of which provide a window-free final flight path to minimize background scattering while allowing rapid changing of the sample and sample environment equipment. ARCS views the SNS decoupled ambient temperature water moderator, using neutrons with incident energy typically in the range from 15 to 1500 meV. This range, coupled with the large detector coverage, allows a wide variety of studies of excitations in condensed matter, such as lattice dynamics and magnetism, in both powder and single-crystal samples. Comparisons of early results to both analytical and Monte Carlo simulation of the instrument performance demonstrate that the instrument is operating as expected and its neutronic performance is understood. ARCS is currently in the SNS user program and continues to improve its scientific productivity by incorporating new instrumentation to increase the range of science covered and improve its effectiveness in data collection.     

Review of the LEED Points Obtained by Canadian Building Projects

The expansion and advancement of businesses, cities, municipalities, and populations in Canada are increasingly demanding the effective usage of land and resources in building development. Companies, organizations, and individuals are seeking to construct more environmentally responsible buildings to help minimize the negative effects that structures place on the natural environment, as well as on the people that have either direct or indirect contact with them. In an effort to set a benchmark for what constitutes a green building, the Canada Green Building Council provides a certification system called Leadership in Energy and Environmental Design (LEED), which is a point scheme that seeks to measure sustainability. Many stakeholders in the construction industry in Canada are increasingly employing this system to validate their achievement in sustainable development. This paper reviews the usage of the LEED system in Canadian building construction and the potential challenges and barriers associated with LEED implementation that specifically pertain to Canadian circumstances. Information from 42 new construction projects across Canada that achieved LEED certification were collected and analyzed. The points most often awarded, as well as those that are granted the least frequently, were tabulated. The percentages of points obtained were compared to American projects. Credit frequency indicators (CFIs), which were used to depict the achievement of credits by each project, can provide decision makers with information on credits awarded in the past and insight into credit implementation in future projects with similar goals. The energy and atmosphere and materials and resources categories proved to have the lowest CFIs, whereas the innovation and design process and water efficiency categories yielded the highest CFIs. The study also found that there were differences in the points obtained by LEED projects in Canada and the United States as some credits are influenced by climate, such as weather and temperature, as well as regional location.     

Abnormal expression of epiligrin and alpha 6 beta 4 integrin in basal cell carcinoma

Lipoprotein lipase (LPL) hydrolyzes the triacylglycerol component of circulating lipoprotein particles, mediating the uptake of fatty acids into adipose tissue and muscle. Insulin is the principal factor responsible for regulating LPL activity in adipose tissue, yet the mechanisms whereby insulin controls LPL expression are unknown. The current studies used wortmannin, a specific inhibitor of phosphatidylinositol (PI) 3-kinase, and rapamycin, a specific inhibitor of activation of phosphoprotein 70 ribosomal protein S6 kinase (p70s6k), to explore some of the components of the insulin signaling pathway controlling LPL activity in adipose cells. Preincubation of isolated rat adipose cells with wortmannin completely abrogated the stimulation of LPL activity by insulin, while preincubation with rapamycin caused approximately a 60% inhibition of insulin-stimulated LPL activity. Thus, the current studies show that the regulation of adipose tissue LPL by insulin is mediated via a wortmannin-sensitive pathway, most likely PI 3-kinase, and that a rapamycin-sensitive pathway, most likely p705s6k, constitutes an important downstream component in the insulin signaling pathway through which LPL is regulated.     

Sclow Plots: Visualizing Empty Space

Scatter plots are mostly used for correlation analysis, but are also a useful tool for understanding the distribution of high‐dimensional point cloud data. An important characteristic of such distributions are clusters, and scatter plots have been used successfully to identify clusters in data. Another characteristic of point cloud data that has received less attention so far are regions that contain no or only very few data points. We show that augmenting scatter plots by projections of flow lines along the gradient vector field of the distance function to the point cloud reveals such empty regions or voids. The augmented scatter plots, that we call sclow plots, enable a much better understanding of the geometry underlying the point cloud than traditional scatter plots, and by that support tasks like dimension inference, detecting outliers, or identifying data points at the interface between clusters. We demonstrate the feasibility of our approach on synthetic and real world data sets.     

Synthesis and characterization of aluminum citrate compounds and evaluation of their influence on the formation of hydrogels based on polyacrylamide

Aluminum citrate is used as a conformance control agent to improve oil production and excess water production. This paper discusses the formation of mono and polynuclear aluminum species from the synthesis of aluminum citrate and evaluates these compounds as crosslinkers in hydrogels for conformance control. The products obtained from the synthesis were characterized by Fourier-transform infrared spectrometry (FTIR), elemental analysis (CHN), scanning electron microscopy (SEM), and inductively coupled plasma–optical emission spectrometry (ICP-OES). The FTIR analyses indicated the presence of mononuclear aluminum citrate complexes at pH 3 and polynuclear species starting at pH 4. These results were corroborated by CHN and ICP-OES techniques, which revealed the variation of carbon, oxygen, hydrogen, and alumina precipitate levels as functions of pH variation. The focus of the study was to assess how these crosslinking agents perform in hydrogel formation under reservoir conditions. Rheological analysis showed that the values of tan (delta) of the hydrogel synthesized with aluminum citrate at pH 6 were lower than 0.1, indicating strong gels, while at pH 9, the values were above 0.1, indicating weak gels. These results are in agreement with those obtained by FTIR, which showed that at pH 6, the structures of the aluminum citrate complex were probably in the form [Al₃(C₆H₅O₇)₃(OH)₄(H₂O)]⁴⁻. This structure appears to allow easier access to the aluminum orbital for the crosslinking process compared to the gel composed of aluminum citrate synthesized at pH 9 [Al₃(C₆H₆O₇)₃(OH)₄(H₂O)₅]⁴⁻.