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It has become commonplace to conduct modal tests with 100–500 accelerometers. Installation and management of the instrumentation is a critical element of the test, both in terms of data quality and time required. In the past 25 years, there have been many advances in transducers, cabling, installation, and data management. TEDS capable accelerometers (also known as smart sensors) with a mounting block and integrated cable have been one significant advance. By using all the available technology and the best practices described here and an experienced test team, the instrumentation phase of a modal test can be accomplished in as little as 1 or 2 days based upon a rate of 15 minutes per accelerometer. And you can avoid or minimize those crossed signals!

Good fixture design will almost always incorporate simplicity into the fixture design and implementation, and it will be relatively low cost. Learning from others in terms of what works and what doesn’t is almost always helpful, and is one of the motivations for the authors to share their experience in this paper. We believe that following the recommended best practices described here will increase the likelihood that your fixture design will achieve the desired result, and not be the subject of a paper on what went wrong in your modal test.

The purpose of this survey was to investigate quality of life and life satisfaction among persons with spinal cord injury (SCI) who require various types of urinary management. A sample of 230 persons with SCI completed the Quality of Life Index (QLI), the Satisfaction With Life Scale (SWLS), and a demographic data form. Findings of this study indicated that there was no significant difference in QLI and SWLS with regard to the type of urinary management used (reflex voiding, indwelling catheter, suprapubic catheter, intermittent catheterization, external catheter or a combination of intermittent catheterization and external catheter). There also was no significant difference in QLI and SWLS with regard to the level of SCI or the incidence of hospitalizations for urinary infections. There were significantly higher QLI and SWLS scores for those with greater abilities to work, attend school, and participate in activities. There also was a significantly higher QLI for those without skin problems associated with urinary dysfunction.

In the first part of this paper, series and product representations of four single-variable triple products T 0 T_0 , T 1 T_1 , T 2 T_2 , T 3 T_3 and four single-variable quintuple products Q 0 Q_0 , Q 1 Q_1 , Q 2 Q_2 , Q 3 Q_3 are defined. Reduced forms and reduction formulas for these eight functions are given, along with formulas which connect them. The second part of the paper contains a systematic computer search for linear trinomial Q Q identities. The complete set of such families is found to consist of two 2-parameter families, which are proved using the formulas in the first part of the paper.

Severe asthma inflicts a tremendous burden on patients with this disease, which is often invisible to others http://ow.ly/RpGk30cTjIF

QuikClot® Combat Gauze® (QCCG) was fielded in 2008 to replace previous generations of hemostatic products. To the best of our knowledge, despite nearly a decade of use, there are no published data on use among US combatant forces. We describe the use of QCCG by ground forces in Afghanistan and compare patients who received QCCG compared with the remaining population in the database who did not receive QCCG.Data were obtained from the Prehospital Trauma Registry (PHTR). Joint Trauma System personnel linked patients to the Department of Defense Trauma Registry (DODTR) for outcome data, when available, upon reaching a fixed facility.Of the 705 patients within the entire PHTR, 118 (16.7%) had documented use of QCCG. Most patients (69.5%) were Afghan; all were male. Lower extremities accounted for the most common site of application (39.7%). Hemorrhage control occurred in 88.3% of encounters with hemorrhage control status documented. Patients receiving QCCG generally had higher rates of concomitant interventions. Of the 705 patients, 190 were linkable to the DODTR for outcome data; 25 of the 28 (89.3%) in the QCCG group were discharged alive compared with 153 of the 162 (94.4%) in the non-QCCG group (ρ = .300).QCCG appears to have common use on the battlefield as a concomitant intervention for obtaining hemorrhage control. Patients receiving QCCG had higher rates of gunshot wounds compared with the baseline population and were generally sicker. Hemorrhage control success was like that reported in other military and civilian settings.

Multilayers and interfaces are ubiquitous in microelectronics devices, interconnect and packaging structures. As the interface integrity becomes the major concern of performance, yield, and reliability, the need to evaluate the fracture and delamination behavior of various interfaces increases. This work focused on quantifying interfacial adhesion performance of a typical electronics packaging structure, flip-chip-on-organic-substrate. A series of experiments and analyzes were conducted to investigate the adhesion and fracture behaviors of the underfill/silicon and underfill/organic substrate interfaces. The experimental techniques for the interfacial fracture experiments were developed to produce the double-cantilever-beam (DCB) specimens and to establish a reproducible testing protocol. To extract the interfacial fracture energies, a closed-form solution was developed based on a beam-on-elastic-foundation model. A two-dimensional elastoplastic finite element analysis (FEA) model was also implemented to examine effects of mode-mixity, thermal/residual stresses, and underfill plasticity. The techniques allow for reproducible determination of underfill/printed circuit board (PCB) and underfill/silicon chip interfacial adhesion strength. The developed techniques are also readily applicable to evaluate interfacial adhesion performance for many other similar electronic packaging systems. This provides capabilities in optimizing material selections and process conditions to improve interfacial adhesion performance, Additionally, the interfacial fracture energy measured with high accuracy can provide a basis for realistic modeling of thermo-mechanical reliability of electronic components.

The flip chip-on-organic-substrate packaging technology utilizes a particulate reinforced epoxy as the underfill (UF) to adhere the chip to the package or board, Although the use of underfill encapsulation leads to improved reliability of flip-chip solder interconnections, delamination at various interfaces becomes a major concern for assembly yield loss and package reliability. In spite of their importance, the adhesion and fracture behaviors of the underfill interfaces have not been investigated until recently. Considerable controversy exists over the effects of underfill formulation and the adhesion and toughening mechanisms of the interfaces. The present work focuses on investigating the effects of several key variables on the interface adhesion strengths for UF/chip and UF/organic substrate systems. These variables are underfill organosilane content, filler particle content, rubber particle content, surface morphology and chemistry of the chip and organic substrates. The approach of this study is to measure the effect of these variables on the interfacial fracture energy using the double-cantilever-beam (DCB) techniques. The results demonstrate that the underfill interfacial adhesion and fracture characteristics are controlled by several distinct but competing mechanisms, such as formation of primary bonds, crack-pinning by glass fillers, debonding of glass filler from epoxy matrix (defect formation), and cavitation and shearing induced by rubber particles. Fundamental understanding of the interfacial adhesion and toughening mechanisms can provide guidance for developing new processes and materials to enhance interfacial adhesion and reliability.

The groundwork for a theory of quadratic identities involving the classical triple and quintuple products is layed. The approach is through the study and use of affine maps that act on indexing lattices associated with the terms (double sums) in the given identity. The terms of the identity are found to be connected by the invariant of a ternary quadratic form.

Modulated differential scanning calorimetry (MDSC) was used to study the glass-transition relaxation behavior in blends of poly(butylene terephthalate) (PBT), a semicrystalline polymer, with polycarbonate (PC), an amorphous polymer. Using a temperature-modulated differential scanning calorimeter (TM-DSC), a sinusoidal temperature oscillation was superimposed upon the underlying linear temperature ramp. The reversing, total, and non-reversing heat flow curves were then analyzed. We examined the efficacy of modulated differential scanning calorimeter (MDSC) to extract glass transitions (Tg) when these were covered over by rapid cold crystallization occurring in the same temperature range. Blends were available in PBT/PC compositions of 80 20 and 40 60 , and with high and low molecular weight, Mw, designated ‘H’ or ‘L’, respectively. Samples of very low initial crystallinity were prepared by rapid quenching from the melt. These samples crystallized immediately during the MDSC scan producing complex exothermic peaks when the scanning temperature increased over Tg. All blends exhibited a lower glass transition assigned to the PBT-rich phase. The upper glass transition, assigned to the PC-rich phase, was never observed in 80 H 20 L , 80 L 20 L , or 40 L 60 L . This suggests that PC-L has better miscibility with amorphous PBT, while producing a very broad, indistinct glass transition in the PC-rich phase. The Fox equation was used to determine the mass fraction composition of the two phases, and confirms that better miscibility is achieved when low molecular weight components are blended. Higher crystalline blends were prepared by melt crystallization. The size of the glass-transition step was greatly reduced in the melt crystallized blends compared to the quenched blends. Nonetheless, MDSC was used successfully to observe dual glass transitions at intermediate temperatures between the Tgs of the homopolymers for all melt crystallized blends, except 80 L 20 L . Analysis of the lower Tg indicates better amorphous phase miscibility in blends with PBT-L and PC-L; analysis of the upper Tg indicates better amorphous phase miscibility in blends with PBT-L.

Adults with disabilities who have completed rehabilitation programs and have returned to active lifestyles are experts on the importance of motivation after an injury or an illness. This qualitative descriptive study was conducted with 9 men and 3 women who had completed a spinal cord injury rehabilitation program at a rehabilitation hospital. The subjects were asked two questions: What helped motivate you during rehabilitation to return to an active, productive life? and How did rehabilitation nurses and staff assist you with that process? An analysis of the interviews revealed five motivational categories--independence, education, socialization, self-esteem, and realization--within the specific themes of nursing and healthcare interventions. Gaining insight into the motivation of adults who have coped with disabilities effectively can help rehabilitation nurses determine how they can promote the motivation that clients need to achieve a quality lifestyle.

Molecular modelling and X-ray structure studies were undertaken to determine the crystalline unit cell of LARC-CPI, a thermoplastic semicrystalline polyimide. We present results of a molecular mechanics based model of the energy minimized unit cell structure. The unit cell of LARC-CPI has lattice parameters of a = 8.0, b = 6.0, c = 37.1A, α = β = γ = 90° as determined from the model. The model unit cell contains two monomer units, one at the centre of four equivalent monomers. This gives a cell density of 1.47 g cm−3 which compares well with the experimentally determined unit cell density of 1.507 ± 0.2 g cm−3. Fibre and powder X-ray diffraction patterns were constructed based on the model unit cell. To compare the model diffraction patterns with experimental data, a novel preparation method developed in earlier work was used to obtain highly oriented LARC-CPI films. Films recrystallized by solvent exposure at the reflux temperature had c-axes preferentially aligned along the film normal. The c-axis repeat length was determined experimentally to be 37.5Ain agreement with the model value. X-ray photoelectron spectroscopy was used to identify the origin of a unique, radiation sensitive diffraction peak observed in some LARC-CPI films. This peak could not be indexed using the proposed model unit cell parameters. We suggest that this peak arises from oriented crystalline diamines, or diamine-terminated chains, located at the film surfaces.

Blends of Poly(butylene terephthalate), PBT, with Polycarbonate, PC, were studied for a range of molecular weights and blend compositions. Blends were available in PBT/PC compositions 80/20 and 40/60, and with Mw designated by H (high) or L (low). Samples were prepared by melt crystallization, or by cold crystallization following a rapid quench from the melt. Addition of PC reduces the crystallization kinetics of PBT so that the resulting crystals are more perfect than those which form in the homopolymer. Degree of crystallinity of the blends followed the rank ordering: L/L > L/H > H/L = H/H. The glass transition behavior was investigated using dynamic mechanical analysis (DMA) and modulated differential scanning calorimetry (MDSC). All blends exhibited two glass transitions at intermediate temperatures between the Tgs of the homopolymers, indicating existence of a PBT-rich phase and a PC-rich phase. Blends L/L were most, and H/H the least, miscible. Small-angle X-ray scattering was performed at room temperature on cold crystallized blends, or at elevated temperature during melt crystallization. The long period was consistently larger, and the linear stack crystallinity was consistently smaller, in blends L/L or H/L. These results indicate that in blends containing low Mw PC, there is more PC located within the PBT-rich phase. The long period was consistently smaller in cold crystallized samples, while the linear stack crystallinity was nearly the same, regardless of melt or cold crystallization treatment. Reduction of the average long period in cold crystallized samples could result from crystallization of PBT within the PC-rich phase. This is consistent with thermal analysis results, which indicate that cold crystallized samples have greater overall crystallinity than melt crystallized samples. A hypothetical liquid phase diagram is presented to explain the differences between melt and cold crystallized blends. © 1996 John Wiley & Sons, Inc.

The subject of this case report was a 67-year-old Caucasian woman who had undergone total knee arthroplasty of the right knee. Postoperative physical therapy and a new orthosis that utilizes principles of stress relaxation (constant displacement) and static progressive stretching were used to reestablish range of motion. The total treatment time (cumulative orthosis wear time) was 32.5 hours over a period of 29 days, and the patient obtained a 17-degree increase in active range of motion. Six months later there was no measurable loss in range of motion. The results of the treatment may be beneficial for some patients. Researchers and clinicians need to conduct studies to further evaluate this approach to knee contracture management.

Solid state structure has been studied for a series of recently synthesized liquid crystalline polycarbonates1 based on methyl-substituted stilbene mesogen and methylene-containing flexible spacer. These polymers are referred to as HMS-n, where n is the number of methylenes in the flexible spacer group. The stability of the liquid crystalline phase and its relationship to the three dimensional crystalline phase were studied. X-ray diffraction patterns of raw fibers drawn from the mesophase revealed that the stability of the mesophase decreases as the methylene spacer length gets close to that of mesogen. From X-ray diffraction patterns of annealed fibers and molecular modeling studies, the unit cell parameters of HMS-5 to 8 were determined. HMS-5 and 6 have an orthorhombic structure while HMS-7 and 8 have a monoclinic structure. More important, an odd-even oscillation is observed in the d-spacings of the (020) and (110) reflections as a function of n, which relates to differences in interchain pa...

Measurements of the coefficient of thermal expansion (CTE) of the crystalline lattice of two semicrystalline thermoplastic polyimides are reported. NEW-TPI and LARC-CPI polyimides were studied using elevated temperature WAXS from 25°C to 325°C. To examine possible shifts in the c-axis, a novel approach developed in our lab was used to create highly oriented samples. Films were treated in NMP at the reflux temperature, washed and then dried under constraint. The films treated in this manner were highly oriented, with c-axes preferentially aligned along the film normal. The advantage of this orientation is that it allows numerous reflections of type (00l) to be examined for temperature shifts of the c-axis using reflection mode WAXS. No systematic shift of the c-axis lattice parameter as a function of temperature was observed in either NEW-TPI or LARC-CPI. The c-axis thermal expansion is concluded to be smaller than 8×10 -6 / o C for LARC-CPI, and for NEW-TPI may be weakly negative. From WAXS of unoriented films, systematic shifts in the a and b lattice parameters were deduced as a function of temperature. The linear CTEs relating these unit cell parameters at temperature T to their values at 0°C are: NEW-TPI a= 7.82(1+93x10 -6 T) b= 6.36(1+60x10 -6 T); LARC-CPI a= 8.06(1+117x10 -6 T) b= 6.12(1+75x10 -6 T).

The bandwidth for high performance networking switches and routers increases two to ten times in every new generation. This in turn drives the bandwidth requirements for the Application Specific Integrated Circuits (ASICs) and their external memory devices designed for the high performance network systems. 3D IC integration with its low power, high density and high bandwidth advantages is proposed to address the bandwidth challenges between the ASIC and its external memory. This paper presents a novel 3D IC architecture that includes a silicon interposer with Through-Silicon-Vias (TSV) and interconnect wiring layers on both sides of the silicon interposer. An ASIC chip measured at 22 mm × 18 mm × 0.4 mm is attached on top of the silicon interposer while two smaller memory chips with a size of 10 mm × 10 mm × 0.4 mm are attached to the bottom of the silicon interposer with micro-bump interconnections. A unique, double-sided Chip to Chip (C2C) joining process is developed to enable the ASIC and memory integration in true 3D System-in-Package (SiP) format. This 3D IC architecture will help to overcome the size limitation of the current silicon interposers due to the reticle size used in the lithographic wafer processing. The 3D IC stack is assembled on an organic package substrate with conventional solder bumps. Communications between the top ASIC die and the bottom memory dice are made through the TSVs and the wiring layers of the silicon interposer. Thermal and thermo-mechanical analysis of the 3D IC stack are used to evaluate the package thermal performance and for optimizing material selection and package reliability. Both the modeling and experimental characterization results are used to gain insights into the 3D IC technology for addressing the ASIC and memory bandwidth challenges and to develop the best practice for ASIC and memory integration for next generation high performance network systems.

In this study, we used simulation technique to analyze the thermal behaviors and investigate the thermal issues of a designed system in package (SiP) for network system application that based on a three dimensional integrated circuit (3D IC) structure. The 3D IC SiP has an interposer which with regularly embedded through-silicon vias (TSVs); there are one CPU chip and two DRAM chips planted on the top side and bottom side of the interposer, respectively. The interposer with chips is bonded on a BT substrate; the BT substrate is bonded on a PCB; and a metallic heat spreader is placed on and glued to the CPU chip's back-side. Because a 3D IC SiP with TSVs is so complicate for modeling and very difficult for meshing, this study attempted to use the equivalent models of embedded TSV, bump/solder bond and metallic trace to simplify a detail 3D IC model. We introduced a slice model, that four stacked chips on an interposer and each chip has two heaters and TSVs, to verify the accuracy and feasibility of the equivalent model by comparing to the detail model, the results of both models show that they are in a good agreement. By using the equivalent model to simulate the studied 3D IC integrated SiP; we found the CPU temperature would be dominated by the cooling capability of a thermal module that attached on the heat spreader. As for the DRAM chips that underneath the interposer, it is inevitable to have a quite high temperature due to the temperature superposition effect and an obstructed heat flow path. In fact, the severely high temperature of the chips under an interposer should be the main thermal issue for such a 3D IC SiP because there is no easy thermal solution for these chips.