Loop Dimensions Research Articles

Mapping Imperfect Loops to Coarse-Grained Reconfigurable Architectures

Nested loops represent a significant portion of application runtime in multimedia and DSP applications, an important domain of applications for coarse-grained reconfigurable architectures (CGRAs). While conventional approaches to mapping nested loops utilize only a single-dimensional pipelining, which is either along the innermost loop or along an outer loop, in this paper, we explore an orthogonal approach of pipelining along multiple loop dimensions by first flattening the loop nest. To remedy the inevitable problem of repetitive outer-loop computation in flattened loops, we present a small set of special operations that can effectively reduce the number and frequency of micro-operations in the pipelined loop. We also present a loop transformation technique that can make our special operations applicable to a broader range of loops, including those with triangular iteration spaces. Our experimental results using imperfect loops from StreamIt benchmarks demonstrate that our special operations can cover a large portion of operations in flattened loops, improve performance of nested loops by nearly 30% over using loop flattening only, and achieve near-ideal executions on CGRAs for imperfect loops.

F.E.M. Parametric Model Optimization of SERB-194C Device Used in Buildings Drift Limitation System

In this paper is presented a new parametric finite elements model of SERB-194C [1] device which is used in protecting the civil engineering structures during earthquakes by limitating the drifts of building stories and dissipating the energy received by the building structure during the earth surface shaking. The goal of this simulation is to determine the influence of the device components dimensions on the variation of forces-displacements device curve. Modifying the device components dimensions, the force-displacements device curve is changing the shape and the area which are related with the capacity of building drift limitation of SERB-194C device. By changing the hysteretic loop shape and dimensions this device can be optimized for different buildings and structures in order to properly diminish the story drift during ground shaking.

Design Formulas for Broadband Concentric Circular-Loops Antennas

This paper presents a simple formulas for designing broadband concentric circular-loops antennas (CCLAs). The loop dimensions for widest bandwidth are expressented in terms of the resonance frequency of the driven loop. The analysis addresses both cases CCLAs with and without ground planes. The presented formulas are employed to design multiple CCLAs. For example, a 3-elements CCLA of a maximum radius of 6.34 cm can be designed to operate with a voltage standing wave ratio (VSWR) < 2 over a frequencies band of a fractional bandwidth of 16.9% with a minimum directivity of 3.9 dB. Addionationally, a 4-elements CCLA of maximum radius of 15 cm can be design to operate in the frequency band extending from 825 MHz to 991 MHz (fractional bandwidth of 18.3%) with a VSWR < 2 and directivity higher than 5.2 dB over the entire band. Furthermore, the analysis shows that a 3-elements CCLA backed with a conducting ground plane improves the fractional bandwidth to 19.6% and directivity to 9.15 dB over the band of interest. The analytical results on designed antennas are validated with simulation results obtained by using the AN-SOF antenna simulation software. An excellent agreement is observed between analytical and AN-SOF simulations results.

Expression of nuclear matrix proteins binding matrix attachment regions in prostate cancer. PARP-1: New player in tumor progression.

Prostate cancer (PCa) displays infrequent point mutations, whereas genomic rearrangements are highly prevalent. In eukaryotes, the genome is compartmentalized into chromatin loop domains by the attachment to the nuclear matrix (NM), and it has been demonstrated that several recombination hot spots are situated at the base of loops. Here, we have characterized the binding between NM proteins and matrix attachment regions (MARs) in PCa. Nontumor and 44 PCa tissues were analyzed. More aggressive tumors were characterized by an increase in the complexity of the NM protein patterns that was synchronous with a decrease in the number of proteins binding the MAR sequences. PARP-1 was the protein that showed the most evident changes. The expression of the PARP-1 associated with NM increased and it was dependent on tumor aggressiveness. Immunohistochemical analysis showed that the protein was significantly overexpressed in tumor cells. To explore the role of PARP-1 in PCa progression, PCa cells were treated with the PARP inhibitor, ABT-888. In androgen-independent PC3 cells, PARP inhibition significantly decreased cell viability, migration, invasion, chromatin loop dimensions and histone acetylation. Collectively, our study provides evidence that MAR-binding proteins are involved in the development and progression of PCa. PARP could play a key role in the compartmentalization of chromatin and in the development of the more aggressive phenotype. Thus, PARP can no longer be viewed only as an enzyme involved in DNA repair, but that its role in chromatin modulation could provide the basis for a new therapeutic approach to the treatment of PCa.

Analysis of absorption characteristics of stacked patch arrays on moderately lossy dielectric layers

It is demonstrated that a square patch array on a moderately lossy dielectric can be transformed into a near-perfect absorber by the addition of a metallic square loop layer between the patch array and the metal back. In this configuration, the condition of perfect absorption can be easily obtained by modifying loop dimensions. The absorption properties of this configuration are analyzed theoretically using an equivalent circuit model and full-wave electromagnetic simulations. Experimental investigations included a bistatic radar cross-section measurement, which ensured that there are no scattered fields in other directions. An array structure built on a commercially available FR4 substrate with copper metallization is used to experimentally validate these results.

An approach to stability analysis and entropy generation minimization in the single-phase natural circulation loops

Single-phase natural circulation loops are frequently used in the systems which are related to the production of renewable energies. Natural circulation systems have low driving head and consequently, low heat removal capability. Thus, minimizing the entropy generation is a critical matter for designing an optimized natural circulation system performance. Moreover, the instability behavior of these systems is one of their most important disadvantages. In the present study, the entropy generation and non-linear stability analysis for a uniform and non-uniform diameter loop under single-phase natural circulation are investigated. In this work, a constant heat flux condition in the heater and constant wall temperature condition in the cooler are assumed. The effect of various parameters such as loop dimensions and heater power on the single-phase natural circulation stability and entropy generation in the loop are analyzed. Finally, the stability of the system in the form of a stability map is discussed, and entropy generation within the loop is calculated.

Effect of different working gases on the performance of a small thermoacoustic Stirling engine

The performance of a small thermoacoustic Stirling heat engine (TASHE) was investigated with three kinds of working gases experimentally and numerically. The examined performances focused on the operating frequency, onset temperature, pressure amplitude and some temperature characteristics after onset. The working frequency with nitrogen, argon and helium as the working gas was 45 Hz, 42 Hz and 130 Hz, respectively. The engine worked with helium in a much wider range of mean pressure than with nitrogen and argon. There was an optimal mean pressure for the minimum onset temperature for each working media. Using nitrogen and argon as working gas rather than helium, another optimal mean pressure for the highest pressure ratio was obtained in the experiment. The loop dimension was indispensable in determining the frequency and the highest pressure ratio was observed in the resonator cavity.

Investigation of all niobium nano-SQUIDs based on sub-micrometer cross-type Josephson junctions

We report on the development of highly sensitive SQUIDs featuring sub-micrometer loop dimensions. The integration of high quality and low capacitance SIS Nb/AlOx/Nb cross-type Josephson tunnel junctions results in white flux noise levels as low as 66 nΦ0 Hz−1/2, well below state-of-the-art values of their Nb-based counterparts based on constriction type junctions. Estimation of the spin sensitivity of the best SQUIDs yield Sμ1/2 < 7μB Hz−1/2 in the white noise region, suitable for the investigation of small spin systems. We discuss fabrication challenges, show results on the electrical characterization of devices with various pickup loops, and describe options for further improvement, which may push the sensitivity of such devices even to single spin resolution.

Optimization of piping expansion loops using ASME B31.3

Piping is the main transportation method for fluids from one location to another within an industrial plant. Design and routing of piping is heavily influenced by the stresses generated due to thermal effects and high pressure of the operating fluid. In particular, pressurized fluids create critical loads on the supports and elbows of the pipe which increases the overall stresses in the piping. Moreover, long pipes operating under high temperature gradients tend to expand significantly. Therefore, designers and engineers usually provide an expansion loop in order to relieve the pipe from the critical stresses. However, expansion loops require extra space, supports, elbows, bends, additional steel structure that could adversely affect the operating cost. It is therefore necessary to optimize the geometry, the number of expansion loops, and the supports. Reducing the number of loops in one single system or reducing the length of the loop itself is always favored as long as stresses are within safe limits. Usually, the commercial software (PipeData) is used in the industry to get the dimensions of the expansion loop. However, this software is mostly based on empirical models that rely on past experience rather than engineering fundamentals. Accordingly, this paper conducts an optimization analysis concerning the expansion loop dimensions and the number of supports without compromising on the safety of piping. The design approach is conducted as per the guidelines of ASME B31.3 (Process Piping) code and uses the commercial software (CAESAR II) for stress calculations. A full comparison for the expansion loop dimension is conducted between the empirical approach and the optimization analysis using ASME B31.3 for one of the existing oilfield projects. Results indicate that optimization reduces the dimensions and the number of expansion loops as well as the total number of supports. This results in significant savings in the piping cost without any compromise on the safety.

Nailfold capillary abnormalities in sclerodermatous chronic GVHD

Chronic GVHD (cGVHD) complicating allo-SCT commonly presents as sclerotic skin changes resembling systemic sclerosis (SSc), suggesting a common pathophysiological pathway. Damage to capillaries is considered an early event in the pathogenesis of SSc, and is associated with characteristic nailfold capillary abnormalities. Whether such nailfold capillary abnormalities occur in sclerodermatous cGVHD is unknown. Nailfold videocapillaroscopy (NVC) was used to evaluate capillary morphology, density and loop dimensions in 14 patients with sclerodermatous cGVHD, 14 sex- and age-matched SSc patients, and 14 healthy controls. It was shown that none of the cGVHD patients and controls, whereas all SSc patients showed severe capillary abnormalities. cGVHD patients and controls showed no differences in capillary density (9.05 vs 9.16 loops/mm, respectively, P=0.84), and capillary loop dimensions (total loop width 44.36 vs 45.56 μm, respectively, P=0.84). Compared with cGVHD patients, SSc patients had a reduced capillary density (9.05 vs 5.25 loops/mm, respectively, P<0.001), and an increase in capillary loop dimensions (total loop width 44.36 vs 99.97 μm, respectively, P=<0.001). In conclusion sclerodermatous cGVHD patients do not show the characteristic microvascular abnormalities seen in SSc, suggesting that capillary damage does not contribute to the pathophysiology of sclerodermatous cGVHD, and making NVC unsuitable for early identification.

Shear behavior of soft-matrix composites reinforced with polyethylene loop-formed fibers

A soft material is defined as a substance that its mechanical properties depend on ambient conditions, e.g. external stresses, temperature, etc. Since composite structures with soft-material matrix do not have adequate pullout resistance with flat-type reinforcements such as fibers, there are a large number of cases where reinforcements with passive resistance are used in conjunction with ordinary fibers. Randomly distributed loop-formed fiber (RDLFF) is a novel idea to reinforce these types of composite materials. Therefore, the main aim of this paper is to use polyethylene RDLFF elements in soft-matrix composites. First, shear behavior of polyethylene RDLFF-reinforced composite was modeled with the use of force-equilibrium method, and then it was compared with that of flat-polyethylene fiber. In the next step, a set of laboratory direct shear tests was conducted on different samples including the neat treatment, polyethylene RDLFF and polyethylene fiber-reinforced composites. Thus, it was shown that through the shearing, a loop-formed fiber has two reinforcing effects including the “fiber effect” and the “loop effect”. The “loop effect” is the main advantage of using RDLFF to ordinary fibers at the same orientation and it is also the major difference in using the two kinds of fibers. The proposed model also indicated that the number of looped-form fibers, fiber diameter, coefficient of friction between fiber and matrix, loop dimension, tensile modulus of fiber, shearing zone and vertical compressive stress determine the shear resistance of RDLFF-reinforced composite. Therefore, the proposed model adequately predicts the shear behavior of soft-matrix composites reinforced with fibers and/or loop-formed fibers.

The Role of Nuclear Matrix Proteins Binding to Matrix Attachment Regions (MARs) in Prostate Cancer Cell Differentiation

In tumor progression definite alterations in nuclear matrix (NM) protein composition as well as in chromatin structure occur. The NM interacts with chromatin via specialized DNA sequences called matrix attachment regions (MARs). In the present study, using a proteomic approach along with a two-dimensional Southwestern assay and confocal laser microscopy, we show that the differentiation of stabilized human prostate carcinoma cells is marked out by modifications both NM protein composition and bond between NM proteins and MARs. Well-differentiated androgen-responsive and slowly growing LNCaP cells are characterized by a less complex pattern and by a major number of proteins binding MAR sequences in comparison to 22Rv1 cells expressing androgen receptor but androgen-independent. Finally, in the poorly differentiated and strongly aggressive androgen-independent PC3 cells the complexity of NM pattern further increases and a minor number of proteins bind the MARs. Furthermore, in this cell line with respect to LNCaP cells, these changes are synchronous with modifications in both the nuclear distribution of the MAR sequences and in the average loop dimensions that significantly increase. Although the expression of many NM proteins changes during dedifferentiation, only a very limited group of MAR-binding proteins seem to play a key role in this process. Variations in the expression of poly (ADP-ribose) polymerase (PARP) and special AT-rich sequence-binding protein-1 (SATB1) along with an increase in the phosphorylation of lamin B represent changes that might trigger passage towards a more aggressive phenotype. These results suggest that elucidating the MAR-binding proteins that are involved in the differentiation of prostate cancer cells could be an important tool to improve our understanding of this carcinogenesis process, and they could also be novel targets for prostate cancer therapy.

Experimental investigations of droplet carryover from the separator drum of an air-lift loop simulating a scaled-down AHWR

Entrainment of phases into each other in a two-phase Natural Circulation Loop is of critical concern in nuclear applications. Despite having serious consequences, such as, radioactivity contamination, hardly any focused study of droplet entrainment from the separator drum has been reported. Hence, a comprehensive experimental study has been performed on an air-lift loop, considering an Advanced Heavy Water Reactor (AHWR) as the prototype. Loop dimensions were obtained following a detailed scaling analysis incorporating natural circulation modelling methodology and entrainment analysis inside the drum. Carryover was observed to increase with air supply rate and generally with drum water level. Porous suppressor plates were employed to reduce droplet entrainment and approximately 94% carryover reduction was achieved for the highest air flow rate employed. Parametric studies characterized the suppressor plates well; carryover rate reduced with reduction in diameter and number of holes in the suppressor plates.

Highly sensitive miniature SQUID magnetometer fabricated with cross-type Josephson tunnel junctions

We report on a new method suitable for the fabrication of highly sensitive SQUID magnetometers exhibiting very small effective areas. In contrast to commonly used approaches, which mostly make use of constrictions in a superconducting material to form the Josephson junctions, we have been able to fabricate such sensors with SIS cross-type Josephson tunnel junctions in an Nb/AlOx/Nb trilayer process. The small junction size and vanishing idle region of our cross-type junctions and a therefore very low capacitance lead to a high sensitivity of the resulting SQUIDs. First results on fabricated miniature SQUID magnetometer within this technology are shown. We found, that even with SQUID loop dimensions of about 10×10μm2 very low flux noise levels could be achieved, which clearly demonstrate the high potential of our approach. Furthermore we estimate the required SQUID parameter which may allow the detection of single electron spin-flips with such devices in the future.

A thin card-sized on-metal UHF-RFID tag using a radiative mushroom structure with an IC chip mounted on a small magnetic loop

In this paper, a novel thin card-sized on-metal 953MHz UHF RFID tag is presented. The RFID tag operates in a unique configuration with an IC chip mounted on a small metallic loop and a radiative mushroom structure. A card-sized 54×86×0.94mm3 tag is designed successfully with a reasonable IC impedance matching with appropriate loop dimensions. It is shown that the reading range performance is tolerant of the environment and the measured reading range is 2.6m on a large 200×300×2mm3 metal board. The reading range is 0.1m longer than a commercial card-sized on-metal tag with much larger thickness of 1.8mm.

Compact Metallic RFID Tag Antennas With a Loop-Fed Method

Several compact, low profile and metal-attachable RFID tag antennas with a loop-fed method are proposed for UHF RFID systems. The structure of the proposed antennas comprise of two parts: (1) The radiator part consists of two shorted patches, which can be treated as two quarter-wave patch antennas or a cavity. (2) A small loop printed on the paper serves as the feeding structure. The small loop provides the needed inductance for the tag and is connected to the RFID chip. The input impedance of the antenna can be easily adjusted by changing loop dimensions. The antenna has the compact size of 80 mm × 25 mm × 3.5 mm, and the realized gain about dB. The measured results show that these antennas have good performance when attached onto metallic surfaces.

Nailfold capillary density is associated with the presence and severity of pulmonary arterial hypertension in systemic sclerosis

Objective:The aim of this study was to investigate whether there are differences in capillary nailfold changes in patients with systemic sclerosis (SSc) with and without pulmonary arterial hypertension (PAH), and...

Confirmation of the INRiM and PTB Determinations of the Si Lattice Parameter

As metrology extends toward the nanoscale, a number of potential applications and new challenges arise. By combining photolithography with focused ion beam and/or electron beam methods, superconducting quantum interference devices (SQUIDs) with loop dimensions down to 200 nm and superconducting bridge dimensions of the order 80 nm have been produced. These SQUIDs have a range of potential applications. As an illustration, we describe a method for characterizing the effective area and the magnetic penetration depth of a structured superconducting thin film in the extreme limit, where the superconducting penetration depth A is much greater than the film thickness and is comparable with the lateral dimensions of the device

Novel Methods of Fabrication and Metrology of Superconducting NanoStructures

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> As metrology extends toward the nanoscale, a number of potential applications and new challenges arise. By combining photolithography with focused ion beam and/or electron beam methods, superconducting quantum interference devices (SQUIDs) with loop dimensions down to 200 nm and superconducting bridge dimensions of the order 80 nm have been produced. These SQUIDs have a range of potential applications. As an illustration, we describe a method for characterizing the effective area and the magnetic penetration depth of a structured superconducting thin film in the extreme limit, where the superconducting penetration depth <formula formulatype="inline"><tex>$\lambda$</tex> </formula> is much greater than the film thickness and is comparable with the lateral dimensions of the device. </para>

Effect of sample loop dimension on lysozyme refolding in size-exclusion chromatography

The formation of misfolded protein aggregates, in particular inclusion bodies, has been widely considered as the major hindrance of good yield in refolding processes. To enhance the performance of protein refolding, extensive efforts were directed toward seeking out methods or means to reduce the aggregate production during the refolding process. Since simultaneous refolding and separation can be feasibly achieved within the packing matrices, size-exclusion chromatography (SEC) has been regarded as an efficient buffer exchange method to enhance protein refolding performance As of now, the effect of the process or operating parameters has yet to be thoroughly investigated. The present work is aimed at understanding how aggregate formation, as well as renaturation yield, varied with the diameter or length of sample loop in size-exclusion chromatography refolding process. Our results showed that not much difference was found in the patterns of aggregate formation for the contraction and the control cases. However, the formation of an additional peak was observed in the expansion cases. In addition, the amount of aggregates was not dependent on the sample loop diameter or length, but instead, influenced by injection volume and protein concentration. It was further concluded that a sample with large volume and low concentration was preferable for refolding process. We believe that the outcome from this work may shed light on the development of a more effective strategy for refolding processes.