Specialized Interposer for Critical Wirebonding on Substrate LGA Semiconductor Package

The trend in semiconductor packages is to become smaller, hence tighter clearances in the design With tight clearances in Fig. 1 denoted by A-D parameters, wirebonding from die to bond finger becomes more critical and challenging, and risk of wire-related rejects increase

Designing and Implementing an OVERFLOW Reader for ParaView and Comparing Performance Between Central Processing Units and Graphical Processing Units

In the Applied Aerosciences and CFD branch at Johnson Space Center, computational simulations are run that face many challenges. Two of which are the ability to customize software for specialized needs and the need to run simulations as fast as possible. There are many different tools that are used for running these simulations and each one has its own pros and cons. Once these simulations are run, there needs to be software capable of visualizing the results in an appealing manner. Some of this software is called open source, meaning that anyone can edit the source code to make modifications and distribute it to all other users in a future release. This is very useful, especially in this branch where many different tools are being used. File readers can be written to load any file format into a program, to ease the bridging from one tool to another. Programming such a reader requires knowledge of the file format that is being read as well as the equations necessary to obtain the derived values after loading. When running these CFD simulations, extremely large files are being loaded and having values being calculated. These simulations usually take a few hours to complete, even on the fastest machines. Graphics processing units (GPUs) are usually used to load the graphics for computers; however, in recent years, GPUs are being used for more generic applications because of the speed of these processors. Applications run on GPUs have been known to run up to forty times faster than they would on normal central processing units (CPUs). If these CFD programs are extended to run on GPUs, the amount of time they would require to complete would be much less. This would allow more simulations to be run in the same amount of time and possibly perform more complex computations

Design and Optimization of a Direct-Conversion Double-Balanced Mixer for RF Receiver Front-End

Differential implementation is becoming highly favoured in RFIC (radio frequency integrated circuit) design, notably its high immunity to common-mode noises, acceptable rejection of parasitic coupling, and increased dynamic range. One specific RF front-end building block that is usually designed as a differential circuit is the mixer.  This technical paper presents a study of a differential mixer, notably the double-balanced mixer implemented on a direct-conversion architecture in a standard 90nm CMOS (complementary metal-oxide semiconductor) process.  Operating frequency is set at 5GHz, which is a typical frequency for RF (radio frequency) receiver.   Impedance matching was essential to fully optimize the mixer design.  The direct-conversion double-balance mixer design eventually achieved conversion gain of 11.463dB and noise figure of 16.529dB, comparable to mixer designs from past research and studies

Die Backside Augmentation for Die Crack Mitigation

Challenges exist for wafer preparation and die attach process in processing thin dice with thickness ranging from 50 µm to 120 µm, or even up to 30 µm thicknes

A disk-wind model with correct crossing of all MHD critical surfaces

The classical Blandford & Payne (1982) model for the magnetocentrifugal acceleration and collimation of a disk-wind is revisited and refined. In the original model, the gas is cold and the solution is everywhere subfast magnetosonic. In the present model the plasma has a finite temperature and the self-consistent solution of the MHD equations starts with a subslow magnetosonic speed which subsequently crosses all critical points, at the slow magnetosonic, Alfven and fast magnetosonic separatrix surfaces. The superfast magnetosonic solution thus satisfies MHD causality. Downstream of the fast magnetosonic critical point the poloidal streamlines overfocus towards the axis and the solution is terminated. The validity of the model to disk winds associated with young stellar objects is briefly discussed. ~Comment: 13 pages, MNRAS accepted for publicatio

Supersymmetry and R-symmetry breaking in models with non-canonical Kahler potential

We analyze several aspects of R-symmetry and supersymmetry breaking in generalized O'Raifeartaigh models with non-canonical Kahler potential. Some conditions on the Kahler potential are derived in order for the non-supersymmetric vacua to be degenerate. We calculate the Coleman-Weinberg (CW) effective potential for general quiral non-linear sigma models and then study the 1-loop quantum corrections to the pseudo-moduli space. For R-symmetric models, the quadratic dependence of the CW potential with the ultraviolet cutoff scale disappears. We also show that the conditions for R-symmetry breaking are independent of this scale and remain unchanged with respect to those of canonical models. This is, R-symmetry can be broken when generic R-charge assignments to the fields are made, while it remains unbroken when only fields with R-charge 0 and 2 are present. We further show that these models can keep the runaway behavior of their canonical counterparts and also new runaway directions can be induced. Due to the runaway directions, the non-supersymmetric vacua is metastable.Comment: 19 pages, revised version with minor changes, references added, published in JHE

Simulations of SSLV Ascent and Debris Transport

A viewgraph presentation on Computational Fluid Dynamic (CFD) Simulation of Space Shuttle Launch Vehicle (SSLV) ascent and debris transport analysis is shown. The topics include: 1) CFD simulations of the Space Shuttle Launch Vehicle ascent; 2) Debris transport analysis; 3) Debris aerodynamic modeling; and 4) Other applications

Evaluación y determinación de agentes físicos y químicos en las operaciones industriales; Cusco, Calca y Quillabamba de la empresa primax en el Proyecto Gasoducto Sur Peruano 2017.

La presente tesis tuvo como objetivo evaluar y determinar los agentes físicos y químicos en las operaciones industriales; CUSCO, CALCA Y QUILLABAMBA de la empresa OSS-PRIMAX en el proyecto GASODUCTO SUR PERUANO, utilizando técnicas de ingeniería para la evaluación y determinación de los factores de riesgo físico/químicos. Mediante un estudio descriptivo y con una población objeto de estudio (n=6) se recolecto información del plano de trabajo del operador de combustible y supervisor de operaciones en todas las operaciones industriales, haciendo uso del diagrama de flujo y la matriz GEMA se identificó que los siguientes factores de riesgo físico/químicos; iluminación, radiación, ruido, compuestos orgánicos volátiles, partículas inhalables y respirables, tienen mayor presencia en las actividades. A través de un monitoreo con equipos certificados de dichos agentes, se procedió a evaluarlos, para el caso de partículas inhalables y respirables se esperó los resultados de laboratorio. Con los resultados obtenidos se determinó si los agentes físicos y químicos presentes en las actividades que desarrollan los trabajadores representan un riesgo laboral, comparando los datos con estándares nacionales e internacionales de higiene ocupacional, se obtuvo que todos los trabajadores de las tres Operaciones Industriales; excepto el supervisor de operaciones de Calca, están expuestos a un nivel alto de radiación, además en el plano de trabajo del supervisor de operaciones de Cusco y Quillabamba (KP28) los niveles de iluminación se encuentran por debajo del Nivel Mínimo Requerido.The objective of this thesis was to evaluate and determine the physicaland chemical agents in industrial operations; CUSCO, CALCA AND QUILLABAMBA of the company OSS-PRIMAX in the project GASODUCTO SURPERUANO, using engineering techniques for the evaluation and determinationof physical / chemical risk factors. Through a descriptive study and with a population under study (n = 6)information was collected from the work plan of the fuel operator and supervisorof operations in all industrial operations, making use of the flow chart and the GEMA matrix identified that the following physical / chemical risk factors; lighting,radiation, noise, volatile organic compounds, inhalable and respirable particles,have a greater presence in activities. Through a monitoring with certified equipment of said agents, weproceeded to evaluate them, for the case of inhalable and respirable particles the laboratory results were expected. With the results obtained it was determined if the physical and chemical agents present in the activities that the workers develop represent a labor risk,comparing the data with national and international standards of occupationalhygiene, it was obtained that all the workers of the three Industrial Operations; except for Calca's operations supervisor, they are exposed to a high level ofradiation, and in the work plan of the operations supervisor of Cusco and Quillabamba (KP28), the lighting levels are below the Required Minimum Level.Tesi

Three-Dimensional Simulations of Jets from Keplerian Disks: Self--Regulatory Stability

We present the extension of previous two-dimensional simulations of the time-dependent evolution of non-relativistic outflows from the surface of Keplerian accretion disks, to three dimensions. The accretion disk itself is taken to provide a set of fixed boundary conditions for the problem. The 3-D results are consistent with the theory of steady, axisymmetric, centrifugally driven disk winds up to the Alfv\'en surface of the outflow. Beyond the Alfv\'en surface however, the jet in 3-D becomes unstable to non-axisymmetric, Kelvin-Helmholtz instabilities. We show that jets maintain their long-term stability through a self-limiting process wherein the average Alfv\'enic Mach number within the jet is maintained to order unity. This is accomplished in at least two ways. First, poloidal magnetic field is concentrated along the central axis of the jet forming a ``backbone'' in which the Alfv\'en speed is sufficiently high to reduce the average jet Alfv\'enic Mach number to unity. Second, the onset of higher order Kelvin-Helmholtz ``flute'' modes (m \ge 2) reduce the efficiency with which the jet material is accelerated, and transfer kinetic energy of the outflow into the stretched, poloidal field lines of the distorted jet. This too has the effect of increasing the Alfv\'en speed, and thus reducing the Alfv\'enic Mach number. The jet is able to survive the onset of the more destructive m=1 mode in this way. Our simulations also show that jets can acquire corkscrew, or wobbling types of geometries in this relatively stable end-state, depending on the nature of the perturbations upon them. Finally, we suggest that jets go into alternating periods of low and high activity as the disappearance of unstable modes in the sub-Alfv\'enic regime enables another cycle of acceleration to super-Alfv\'enic speeds.Comment: 57 pages, 22 figures, submitted to Ap

Extended Hauser-Feshbach Method for Statistical Binary-Decay of Light-Mass Systems

An Extended Hauser-Feshbach Method (EHFM) is developed for light heavy-ion fusion reactions in order to provide a detailed analysis of all the possible decay channels by including explicitly the fusion-fission phase-space in the description of the cascade chain. The mass-asymmetric fission component is considered as a complex-fragment binary-decay which can be treated in the same way as the light-particle evaporation from the compound nucleus in statistical-model calculations. The method of the phase-space integrations for the binary-decay is an extension of the usual Hauser-Feshbach formalism to be applied to the mass-symmetric fission part. The EHFM calculations include ground-state binding energies and discrete levels in the low excitation-energy regions which are essential for an accurate evaluation of the phase-space integrations of the complex-fragment emission (fission). In the present calculations, EHFM is applied to the first-chance binary-decay by assuming that the second-chance fission decay is negligible. In a similar manner to the description of the fusion-evaporation process, the usual cascade calculation of light-particle emission from the highly excited complex fragments is applied. This complete calculation is then defined as EHFM+CASCADE. Calculated quantities such as charge-, mass- and kinetic-energy distributions are compared with inclusive and/or exclusive data for the $^{32}$S+$^{24}$Mg and $^{35}$Cl+$^{12}$C reactions which have been selected as typical examples. Finally, the missing charge distributions extracted from exclusive measurements are also successfully compared with the EHFM+CASCADE predictions.Comment: 34 pages, 6 Figures available upon request, Phys. Rev. C (to be published