Generation Package Research Articles

Failure of package boilers in a petrochemical plant

AbstractThe paper deals with the failure investigation of furnace‐tubes of a few medium capacity (86 T/H steam generation) package boilers in a petrochemical plant. As a consequence of damage, the boilers required major tube‐repair on urgent basis, and complete tube replacement within a period of two years. Failure of different boilers took place at varying service durations, though all of them had the same design and criteria of operation. The study included metallurgical characterization of the failed components; analysis of operation and process (historical) data; review of inspection and maintenance records; evaluation of design and water‐treatment practices; etc. As a result, water‐side corrosion was attributed to be the cause of tube‐leakage via general and localized corrosion mechanism, while, no metallurgical defects and changes were noticed in the failed components. On the other hand, process and operational abnormalities were diagnosed as the root cause of trouble initiation and propagation. In order to avoid the recurrence of such failures, various preventive measures (inspection, maintenance, operation and process) have been recommended.

Fabrication and characterization of fine pitch on-chip copper interconnects for advanced wafer level packaging by a high aspect ratio through AZ9260 resist electroplating

In this paper, we report the fabrication of high aspect ratio, highly dense, very fine pitch on-chip copper-pillar-based interconnects for advanced packaging applications. Photoresist molds up to a thickness of 80 µm and having feature sizes as small as 5 µm were fabricated using multi-step coating of the positive tone AZ9260 photoresist. Spin coating and lithography parameters were optimized to achieve smooth and vertical sidewalls. Copper interconnects having an aspect ratio up to 6 and a pitch size of 25 µm were electroplated in the fabricated resist mold. Due to a very small pitch size, the total number of interconnects per cm2 chip area is 160 000, which is much larger than the conventional solder-based interconnects. The electrical resistance of the electroplated copper interconnects was measured by 4-probe kelvin measurement configuration and was found to be in the range of 8–10 mΩ and the corresponding electrical resistivity was calculated as 2.4 µΩ cm. Such low resistive interconnects can carry much larger electrical current without significant electrical loss, which is ideally suitable for next generation packaging applications. X-ray diffraction has shown the presence of the (2 2 0) texture along the length of electroplated copper pillars. Transmission electron microscope reveals the presence of nanoscale copper twins along the length of copper interconnects.

CONSTRUCTION OF CROSSOVER DESIGNS WITH CORRELATED ERRORS

SummaryCrossover experiments are widely used, particularly where a sequence of treatments is given to subjects. Correlations between observations on the same subject are therefore likely and should be considered in both the design and analysis of crossover experiments. This paper presents an algorithm for the generation of efficient crossover designs with autoregressive and linear variance structures. The algorithm has been implemented as a module in the experimental design generation package CycDesigN (Release 3.0; CycSoftware, Hamilton, New Zealand). Output from the algorithm is compared with earlier work. Some results are given from the analysis of a crossover experiment assuming correlated errors.

MicrOMEGAs 2.0: A program to calculate the relic density of dark matter in a generic model

micrOMEGAs 2.0 is a code which calculates the relic density of a stable massive particle in an arbitrary model. The underlying assumption is that there is a conservation law like R-parity in supersymmetry which guarantees the stability of the lightest odd particle. The new physics model must be incorporated in the notation of CalcHEP, a package for the automatic generation of squared matrix elements. Once this is done, all annihilation and coannihilation channels are included automatically in any model. Cross-sections at v = 0 , relevant for indirect detection of dark matter, are also computed automatically. The package includes three sample models: the minimal supersymmetric standard model (MSSM), the MSSM with complex phases and the NMSSM. Extension to other models, including non-supersymmetric models, is described. Program summary Title of program:micrOMEGAs2.0 Catalogue identifier:ADQR_v2_0 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADQR_v2_0 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Computers for which the program is designed and others on which it has been tested:PC, Alpha, Mac, Sun Operating systems under which the program has been tested:UNIX (Linux, OSF1, SunOS, Darwin, Cygwin) Programming language used:C and Fortran Memory required to execute with typical data:17 MB depending on the number of processes required No. of processors used:1 Has the code been vectorized or parallelized:no No. of lines in distributed program, including test data, etc.:91 778 No. of bytes in distributed program, including test data, etc.:1 306 726 Distribution format:tar.gz External routines/libraries used:no Catalogue identifier of previous version:ADQR_v1_3 Journal reference of previous version:Comput. Phys. Comm. 174 (2006) 577 Does the new version supersede the previous version:yes Nature of physical problem:Calculation of the relic density of the lightest stable particle in a generic new model of particle physics. Method of solution: In numerically solving the evolution equation for the density of dark matter, relativistic formulae for the thermal average are used. All tree-level processes for annihilation and coannihilation of new particles in the model are included. The cross-sections for all processes are calculated exactly with CalcHEP after definition of a model file. Higher-order QCD corrections to Higgs couplings to quark pairs are included. Reasons for the new version:There are many models of new physics that propose a candidate for dark matter besides the much studied minimal supersymmetric standard model. This new version not only incorporates extensions of the MSSM, such as the MSSM with complex phases, or the NMSSM which contains an extra singlet superfield but also gives the possibility for the user to incorporate easily a new model. For this the user only needs to redefine appropriately a new model file. Summary of revisions: • Possibility to include in the package any particle physics model with a discrete symmetry that guarantees the stability of the cold dark matter candidate (LOP) and to compute the relic density of CDM. • Compute automatically the cross-sections for annihilation of the LOP at small velocities into SM final states and provide the energy spectra for γ , e + , p ¯ , ν final states. • For the MSSM with input parameters defined at the GUT scale, the interface with any of the spectrum calculator codes reads an input file in the SUSY Les Houches Accord format (SLHA). • Implementation of the MSSM with complex parameters (CPV-MSSM) with an interface to CPsuperH to calculate the spectrum. • Routine to calculate the electric dipole moment of the electron in the CPV-MSSM. • In the NMSSM, new interface compatible with NMHDECAY2.1. Typical running time:0.2 sec Unusual features of the program:Depending on the parameters of the model, the program generates additional new code, compiles it and loads it dynamically.

The autoignition of cyclopentane and cyclohexane in a shock tube

Ignition delay times of cyclohexane–oxygen–argon and cyclopentane–oxygen–argon mixtures have been measured in a shock tube, the onset of ignition being detected by OH radical emission. Mixtures contained 0.5 or 1% of hydrocarbon for values of the equivalence ratio ranging from 0.5 to 2. Reflected shock waves allowed temperatures from 1230 to 1840 K and pressures from 7.3 to 9.5 atm to be obtained. These measurements have shown that cyclopentane is much less reactive than cyclohexane, as for a given temperature the observed autoignition delay times were about 10 times higher for the C 5 compound than for the C 6. Detailed mechanisms for the combustion of cyclohexane and cyclopentane have been proposed to reproduce these results. The elementary steps included in the kinetic models of the oxidation of cyclanes are close to those proposed to describe the oxidation of non cyclic alkanes and alkenes. Consequently, it has been possible to obtain these models by using an improved version of the EXGAS software, a computer package for the automatic generation of detailed kinetic models for the gas-phase combustion of alkanes and alkenes. Nevertheless, the modeling of the oxidation of cyclanes requires new types of generic reactions to be considered, and especially to define new correlations for the estimation of the rate constants. Quantum chemical calculations have been used to improve the estimation of some sensitive rate constants in the case of cyclopentane. The main reaction pathways have been derived from flow rate and sensitivity analysis.

Heuristic Methods for Automatic Rotating Workforce Scheduling

Rotating workforce scheduling appears in different forms in a broad range of workplaces, such as industrial plants, call centers, public transportation, and airline companies. It is of a high practical relevance to find workforce schedules that fulfill the ergonomic criteria of the employees, and reduce costs for the organization. In this paper we propose new heuristic methods for automatic generation of rotating workforce schedules. To improve the quality of each heuristic method alone, we further propose the hybridization of these methods. The following methods are proposed: (1)A Tabu Search (TS) based algorithm, (2) A heuristic method based on min-conflicts heuristic (MC), (3) A method that includes in the tabu search algorithm the min-conflicts heuristic (TS-MC) and random walk (TS-RW), (4) A method that includes in the min-conflicts heuristic the tabu mechanism (MC-T), random walk (MC-RW), and both the tabu mechanism and the random walk (MC-T-RW). The appropriate neighborhood structure, tabu mechanism, and fitness function, based on the specifics of the problem are proposed. The proposed methods are implemented and experimentally evaluated on the benchmark examples given in the literature and on the real life test problems, which we collected from a broad range of organizations. Empirical results show that the combination of the min-conflicts heuristic with tabu search can be used to solve this problem very effectively. The hybrid methods improve the performance of the commercial system for generation of rotating workforce schedules and are currently in the procees of being included in a commercial package for automatic generation of rotating workforce schedules.

BatTri: A two-dimensional bathymetry-based unstructured triangular grid generator for finite element circulation modeling

A brief summary of Delaunay unstructured triangular grid refinement algorithms, including the recent “off-centers” method, is provided and mesh generation requirements that are imperative to meet the criteria of the circulation modeling community are defined. A Matlab public-domain two-dimensional (2-D) mesh generation package (BatTri) based on these requirements is then presented and its efficiency shown through examples. BatTri consists of a graphical mesh editing interface and several bathymetry-based refinement algorithms, complemented by a set of diagnostic utilities to check and improve grid quality. The final output mesh node locations, node depths and element incidence list are obtained starting from only a basic set of bathymetric data. This simple but efficient setup allows fast interactive mesh customization and provides circulation modelers with problem-specific flexibility while satisfying the usual requirements on mesh size and element quality. A test of the “off-centers” method performed on 100 domains with randomly generated coastline and bathymetry shows an overall 25% reduction in the number of elements with only slight decrease in element quality. More importantly, this shows that BatTri is easily upgradeable to meet the future demands by the addition of new grid generation algorithms and Delaunay refinement schemes as they are made available.

The new Los Alamos opacity code ATOMIC

In this work we report on developments of ATOMIC, a Los Alamos code designed to compute opacities under both LTE and non-LTE conditions for a large range of elements. We report here, for the first time, data associated with the newly generated Rosseland opacity table for oxygen. In addition, the various equation-of-state packages, absorption spectra generation packages, and parallel techniques used in the generation of this table will be discussed.

Thermal Issues in Next-Generation Integrated Circuits

The drive for higher performance has led to greater integration and higher clock frequency of microprocessor chips. This translates into higher heat dissipation and, therefore, effective cooling of electronic chips is becoming increasingly important for their reliable performance. We systematically explore the limits for heat removal from a model chip in various configurations. First, the heat removal from a bare chip by pure heat conduction and convection is studied to establish the theoretical limit of heat removal from a bare die bound by an infinite medium. This is followed by an analysis of heat removal from a packaged chip by evaluating the thermal resistance due to individual packaging elements. The analysis results allow us to identify the bottlenecks in the thermal performance of current generation packages, and to motivate lowering of thermal resistance through the board-side for efficient heat removal to meet ever increasing reliability and performance requirements.

BaTiO3 Films by Low-Temperature Hydrothermal Techniques for Next Generation Packaging Applications

This work reports synthesis, characterization and integration of sub-micron thick nano-grained barium titanate films on organic Printed Wiring Boards (PWB). Barium titanate films were synthesized on titanium foils at 95∘C. SEM of films revealed 80 nm grains. The films were characterized using XRD, FTIR and Raman spectroscopy. As-synthesized films exhibited high capacitance densities and dielectric loss. The films were treated with oxygen plasma to reduce entrapped hydroxyl groups and this resulted in improved dielectric properties. The plasma treated films exhibited a capacitance density of 1 μ F/cm2 and a dielectric loss of 0.06. The high frequency dielectric properties were extracted from s-parameter measurements on CPW structures on these films and were found to be stable up to 8 GHz.

67. Bovine Immunodeficiency Virus Based Lentiviral Vector with Improved Safety Features

Replication competent lentivirus (RCL) has been the major safety concern associated with applications of lentivirus based gene transfer systems for human gene therapy. Minimization and elimination of overlaps between the packaging and the transfer vector constructs are expected to reduce the potential to generate RCL. We previously developed second and third generation Bovine Immunodeficiency Virus (BIV) based gene transfer systems (M. Matukonis, M. Li, R. P. Molina, B. Paszkiet, M. Kaleko, and T. Luo, 2002, Hum. Gene Ther. 13,1293–1303). However, some sequence homologies between the vector and gag/pol packaging constructs remained. We now describe a fourth generation packaging construct in which the gag/pol was recoded with codon usage optimized for expression in human cells. Expression of the recoded gag/pol was Rev/RRE independent. Thus, RRE was eliminated from the packaging construct, thereby removing a 312 bp block of homology. In addition, recoding gag/pol minimized overall homologies between the packaging and transfer vector constructs. The longest homologous sequence between the packaging construct and the transfer vector construct is only 8 bps. Moreover, recoding resulted in a 10-fold improvement in Gag/Pol expression levels. Vectors generated by the recoded packaging construct with a four plasmid system had titers greater than 1 × 106 transducing units per milliliter, equivalent to those of the earlier generation systems. The vectors were functional in vitro and efficiently transduced rat pigment epithelial cells in vivo. Generation of the synthetic packaging construct provides further advances to the safety of lentiviral vectors for clinical applications.

A note on the Design of Unreplicated Trials

AbstractOne approach to the design of early generation trials is to have a number of replicated check varieties and a larger number of unreplicated or new varieties. For such trials we define the class of α–α‐designs as an extension to the augmented lattice square designs of Federer (2002). Efficient latinized α–α‐designs can be conveniently constructed using the design generation package CycDesigN.

Trace analysis of Erlang programs

The paper reports on an experiment to provide the Erlang programming language with a tool package for convenient trace generation, collection and to support analysis of traces using a set of techniques. Due to the frequent use of state-based software design patterns in Erlang programming we can in many cases recover not only the events from a trace log, but also the program states causing these events. This makes it possible to obtain program models from execution traces. In our work we make use of these program models for program visualization and model checking.

Development of a dual-robot system for prototype production

A dual-robot machining system has been developed for manufacturing complex objects. The system consists of two six-axis industrial robots with flexible tool changers, a CAD/CAM package for geometric design and toolpath generation, a robot simulation package for collision avoidance, and a vision system for robot calibration. It offers the flexibility to reconfigure the robots of the system to accommodate workpieces of different shapes and sizes. A prototype of the system has been successfully developed and tested, and shows satisfactory performance in machining quality and control over the configurations of the robots. Examples are given of the application of the system to machining objects with spherical and sculptured surfaces. The system has been shown to be flexible, reconfigurable, automatic, and capable of manufacturing complex prototypes in the current industry environment.

3D anisotropic mesh refinement in compliance with a general metric specification

A simple and efficient anisotropic refinement procedure for the three-dimensional tetrahedral element mesh based on successive bisection of edges is proposed. Refinement is done by dividing lines of the mesh based on the lengths calculated on three points as specified by the metric tensor along the direction of the line. To obtain the best mesh quality, the subdivision of line segments is performed in the sequence according to the length of the line segments to be divided. Such an order of priority can be determined by a simple sorting process on all the line segments for which refinement is needed. This list of ordered line segments has to be updated from time to time to take into account the new line segments generated during the subdivision process. From the examples studied, the CPU time for mesh refinement seems to bear a linear relationship with the number of elements generated, with a refinement rate of up to 30 000 elements/s on an IBM Power Station 3BT. Shape optimization procedures can be applied to the refined mesh to further improve the quality of the elements. The refinement scheme is useful as part of a general three-dimensional mesh generation package, or as the mesh refinement module in an adaptive finite element analysis.

P‐63: Development of AC‐PDP Tubeless Packaging Method and their Operating Characteristics

AbstractIn this work, we have improved new tubeless packaging technologies using an indirect glass‐to‐glass electrostatic bonding and an organic binder bonding to the PDP. Both methods were performed more at less temperature than 200°C. AC‐PDPs were successfully packaged in He‐Ne(27%)‐Xe(3%) and the packaging properties were compared with conventional method. We observed light emission and the operation characteristics as function of time variation were investigated. Also, we proposed next generation packaging method.

Development of a suspension packaging cell line for production of high titre, serum-resistant murine leukemia virus vectors.

To date, only adherent cell lines have been used for the generation of packaging cells for the production of type C retrovirus vectors. The large-scale production of high titre retrovirus vectors could benefit from the development of packaging cells growing in suspension. Here, we describe the ability of two different lymphoid cell lines, one B- and one T-lymphoblastoid cell line (Namalwa and CEM, respectively), to produce MLV-based vectors. Upon transfection with a third generation packaging construct, the virus particle production by Namalwa cells was characterised by low RT-activity, and by CEM cells as high RT activity as previously established adherent packaging cells. An amphotropic packaging cell line (CEMFLYA) was therefore established from CEM cells. Upon introduction of a lacZ vector genome, the novel packaging cell line produced vector particles routinely in the region of 10(7) infectious units/ml. The vectors were helper-free and highly stable in fresh human serum. The potential for scaled up vector production was demonstrated by continuous culture of the new packaging cells for 14 days in a 250 ml spinner flask. These suspension packaging cells should be applicable to large bioreactor systems to bulk produce high titre, complement-resistant retrovirus vectors for gene therapy.

Safety considerations in vector development.

The inadvertent production of replication competent retrovirus (RCR) constitutes the principal safety concern for the use of lentiviral vectors in human clinical protocols. Because of limitations in animal models to evaluate lentiviral vectors for their potential to recombine and induce disease, the vector design itself should ensure against the emergence of RCR in vivo. Issues related to RCR generation and one approach to dealing with this problem are discussed in this chapter. To assess the risk of generating RCR, a highly sensitive biological assay was developed to specifically detect vector recombination in transduced cells. Analysis of lentiviral vector stocks has shown that recombination occurs during reverse transcription in primary target cells. Rejoining of viral protein-coding sequences of the packaging construct and cis-acting sequences of the vector was demonstrated to generate env-minus recombinants (LTR-gag-pol-LTR). Mobilization of recombinant lentiviral genomes was also demonstrated but was dependent on pseudotyping of the vector core with an exogenous envelope protein. 5' sequence analysis has demonstrated that recombinants consist of U3, R, U5, and the psi packaging signal joined with an open gag coding region. Analysis of the 3' end has mapped the point of vector recombination to the poly(A) tract of the packaging construct's mRNA. The state-of-the-art third generation packaging construct and SIN vector also have been shown to generate env-minus proviral recombinants capable of mobilizing retroviral DNA when pseudotyped with an exogenous envelope protein. A new class of HIV-based vector (trans-vector) was recently developed that splits the gag-pol component of the packaging construct into two parts: one that expresses Gag/Gag-Pro and another that expresses Pol (RT and IN) fused with Vpr. Unlike other lentiviral vectors, the trans-vector has not been shown to form recombinants capable of DNA mobilization. These results indicate the trans-vector design prevents the generation of env-minus recombinant lentivirus containing a functional gag-pol structure (LTR-gag-pol-LTR), which is absolutely required for retroviral DNA mobilization and the emergence of RCR. Quality assurance based on monitoring for RCR may have limitations as a predictor of safety in vivo, especially in the long term. The demonstration of lentivirus infection via alternative entry mechanisms supports this notion. Therefore, the approach of monitoring trans-vector stocks for env-minus recombinant virus in vitro as a surrogate marker for the possible emergence of RCR in vivo should represent a significant advancement in vector safety quality assurance.

3D image acquisition and NURBS based geometry modelling of natural objects

This paper presents a recently developed Image Acquisition–Geometric Modelling system for the construction of geometric models of natural or artificial objects. This construction is achieved in a two-step procedure. First, the object of interest is digitised, i.e. points on the surface of the object are computed. Then, based on the cloud of digitised 3D points, an approximating surface, a geometric model of the object of interest, is constructed. Coupled with a mesh generation package, the system presented allows for further processing and analysis of the resulting model instead of the real object itself.

Fabrication of a Fully Integrated Passive Module for Filter Application Using MCM-D Compatible Processes

Integral passive is an emerging technology which is currently perceived as a possible alternative to the discrete passive technology in fulfilling the next generation packaging needs. Although discrete surface mount passive components (resistors, capacitors, and inductors) have been well characterized, the development of integral passive components suitable for co-integration on the board level is relatively recent. Since in some applications the number of passive components can exceed the number and the area of IC chips on a circuit board or in a package, such integration of passive components would be necessary to substantially eliminate part count and reduce device area. To address these issues, integration technology for passive elements in the same manner as for transistors is necessary. In addition, the fabrication sequence of all integral passive components should be mutually compatible for co-integration on the same substrate. In this paper, materials and fabrication issues for passive elements such as resistors (R), capacitors (C), and inductors (L) and the feasibility of integration of these fabricated passive components on glass substrates have been addressed. An active filter circuit has been selected for a case study for R, L, and C co-integration. This passive module contains eleven resistors, four capacitors, and four inductors, and is fabricated using MCM-D (multichip module-deposited) compatible processes. A variety of materials appropriate for fabrication of integral passives in a mutually compatible fashion were investigated, including chromium and nickel-chromium resistors, composites of high dielectric constant materials in epoxies for capacitor dielectrics, and composites of magnetic ferrite particles in polyimides for inductor core and shielding. The fabricated devices showed good agreement between the design values and the corresponding measured values. It is anticipated that some of these materials and fabrication processes can be implemented for the MCM-L (multichip module-laminate) compatible packaging. © 2000 Kluwer Academic Publishers