Compressed Profile Research Articles

NEW SPECIES OF COILED NAUTILOIDS FROM THE PENNSYLVANIAN OF THE DONETS BASIN, UKRAINE

Two new species of coiled nautiloids, Gzheloceras poletaevi sp. nov. and Celox oliphanti sp. nov., are described from the Late Bashkirian and Early Moscovian of the Central Donets Basin, Ukraine. Gzheloceras poletaevi sp. nov. differs from Gzheloceras aisenvergi in absence of a longitudinal ridge on the ventolateral shoulder and more compressed whorl profile; Gzheloceras poletaevi differs from Gzheloceras striatum in absence of a spiral lateral ribs and less compressed whorl. Gzheloceras poletaevi is distinguished from Gzheloceras memorandum by more compressed whorl profile and thinly discoidal conch. Gzheloceras poletaevi differs from Gzheloceras pulcher in the absence of a thin transverse lateral ribs and longitudinal ridge on the ventolateral shoulder. Celox oliphanti sp. nov. differs from Celox erratica by delicate growth lines on the conch surface and more rapid whorl’s increase in width and height.

Experimental study of the bearing capacity of compressed steel struts of an I-beam profile in conditions of constrained torsion

Wide application in the construction of thin-walled steel rods of an open profile requires taking into account the peculiarities of the work of load-bearing structural elements under the action of the entire complex of loads. For a number of rod systems consisting of I-beam profiles, it is impossible to exclude torsion under the action of compressive forces, which leads to the appearance of additional normal stresses in the profile. In this regard, it is necessary to study the actual operation of compressed I-beams under the action of torsional loads. The bearing capacity of a compressed I-beam profile strut with constrained torsion is considered. The method of conducting an experimental study of a centrally and off-center compressed I-beam profile strut under the action of longitudinal force and bimoment is presented. The analysis of the effect of the bimoment on the bearing capacity of a centrally and off-center compressed thin-walled rod of an open profile with constrained torsion is performed. The bearing capacity of the centrally and off-center compressed I-beam profile strut from the action of longitudinal force and bimoment was experimentally determined, which was compared with the results of numerical calculations in finite element formulation, taking into account geometric and physical nonlinearity in conditions of constrained torsion. According to the results of the experiment, the possibility of using numerical modeling to assess the stability of centrally and off-center compressed thin-walled rods was established. open profile with constrained torsion under various schemes of external force.

USING ZERO-WASTE BASELINES TO IDENTIFY COMPRESSED AIR SYSTEM INEFFICIENCIES IN DEEP-LEVEL MINES

Inefficient compressed air systems in deep-level mines deteriorate energy performance and increase operational costs. Leaks, wastages, and misuse are common inefficiencies that necessitate an oversupply of compressed air. It is therefore important to identify where the opportunities for improvement are located. Underground mining equipment can be used to develop a zero-waste compressed air demand profile. This profile can then be simulated for the entire operation to determine a theoretical baseline. Noticeable inefficiencies are then identified by comparing the actual data with the zero-waste baselines. The results of this study showed that the surface operations oversupply compressed air by 15% (10 kg/s of air) per day. This requires an additional 80 MWh of electricity (14.5% of the total) and costs approximately R91 000 per day. The comparison with the zero-waste baselines showed that 7.9 kg/s of air is wasted at the underground levels during drilling periods, highlighting the areas that require mitigation projects to improve the performance while decreasing costs and wastages. Keywords zero-waste baseline; compressed air; deep-level mine

Carbon ablator areal density at fusion burn: Observations and trends at the National Ignition Facility

For inertial confinement fusion experiments, the pusher is composed of a high-density deuterium tritium cyrogenic fuel layer and an ablator, often made of carbon. In an ideal, no-mix implosion, increasing the areal density of the pusher transfers more pressure to the hot spot and increases the hot spot confinement time. There has been a lack of knowledge about the final compressed state of the ablator for implosions at the National Ignition Facility. 14 MeV fusion neutrons inelastically scattering on the remaining carbon ablator excites a nuclear metastable state that emits a prompt 4.4 MeV gamma ray. The gamma reaction history diagnostic data, when reduced by a new data analysis technique, can isolate and measure the carbon gamma rays, which are proportional to the areal density of the ablator during fusion burn. The trends over many National Ignition Facility campaigns show that the ablator areal density is weakly sensitive to the maximum shell velocity, the cold fuel radius, the ablator mass remaining, or the laser picket intensity. Controlled parameter scans reveal that, for specific campaigns, ablator compression has a strong dependence on laser coast time, high Z dopants, and the laser drive foot duration. Using a model of the compressed ablator density profile reveals that the greatest variation of the ablator areal density comes from its thickness, with highly compressed, thin layers having high areal density values. The compression and thickness of the ablator are other metrics that designers should understand to differentiate the types of capsule degradation and maximize the inertial confinement fusion performance.

COMPRESSED FLANGES OF ARCHED STEEL THIN-WALLED COLD-ROLLED PROFILED SHEETS: DETERMINATION OF RESIDUAL STRESSES

Introduction. The construction sphere widely uses steel thin-walled cold-formed profiles. In arched steel coldformed trapezoidal section profiles, residual normal stresses oriented along the profile occur at the stage of manufacturing arched blanks from flat profiled sheets and are caused by the cold bending process involving the extreme zones of the profile in the plastic stage with unloading without subsequent heat treatment. According to preliminary estimates, the residual stresses are up to one third of the calculated resistance of sheet steel at small radii of the arch profile. At present, the researchers do not take into account the residual technological stresses of the longitudinal bending when designing structures from thin-walled longitudinally bent rolled trapezoidal sections. The purpose of the paper is to develop a method for determining residual stresses in compressed flanges of arched steel thin-walled cold-rolled profiled sheets, which provides simplicity of the measurement and calculation methods, reliability and high accuracy of the obtained stress values.Materials and methods. The authors made the analysis of previously published materials and identified the advantages and disadvantages of previous studies. Moreover, the authors showed the advantages of the proposed method for determining the residual technological normal stresses in compressed flanges of arched steel thin-rolled profiled steel.Results. The researches formed a new method for making sections of a compressed shelf and measuring residual normal stresses in the compressed flanges of an arched steel sheet of cold-rolled profiled steel. The proposed method greatly simplified the existing method of determining residual technological normal stresses in compressed profile flanges, improved the accuracy of measuring normal stresses in compressed profile flanges.Discussion and conclusions. The method of measuring residual process stresses allows improving existing methods for determining residual stresses, simplifying calculations, as well as improving the accuracy of stresses. In the future, the authors will make a numerical simulation of the bending arch profiles, as well as an experimental assessment of the adequacy of the proposed method.The authors have read and approved the final manuscript. Financial transparency: the authors have no financial interest in the presented materials or methods. There is no conflict of interest.

Physical activity patterns and multimorbidity burden of older adults with different levels of functional status: NHANES 2003–2006

BackgroundPhysical function and physical activity decrease with age, but differences in physical activity patterns within different physical functioning groups are unknown. ObjectivesTo describe physical activity patterns and multimorbidity burden by physical function group and age. MethodsActigraph accelerometer-derived physical activity patterns were compared by physical function (high functioning, activity limitations, activity of daily living disabled) determined by questionnaire and age among 2174 older adults (mean age = 70.9, sd = 0.2 years) from the cross-sectional 2003–2006 National Health and Nutrition Examination Survey. Associations between physical function, physical activity, and multimorbidity were examined. ResultsReduced physical function and increased age were associated with lower physical activity, increased sedentary time and a compressed activity profile. During the most active hour of the day (11:00 a.m.), the oldest, lowest physical functioning group was 82% less active than the youngest, highest physical functioning group. High functioning had over 30% more total activity counts, over 56% more time in moderate-to-vigorous activity, about 8% less time sedentary and took approximately one more sedentary break/hour than lower physical functioning groups. Gender differences in physical activity variables were prevalent for high functioning, but limited within reduced physical functioning groups. Physical function, age, total activity counts/day, and breaks in sedentary time/day were independently associated with multimorbidity (p < 0.005). ConclusionsReduced physical function and increased age are associated with physical activity levels, and all three are associated with multimorbidity. Understanding physical activity differences by physical function is important for designing interventions for older individuals at increased risk for mobility disability.

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Buccinum macleani n. sp., from off Fort Bragg, Mendocino County, California, is described. The new species is placed tentatively in the genus Buccinum (s.l.), based on radular characteristisc and shell morphology. It differs from all other eastern Pacific Buccinum by its very compressed profile.

Spin polarisation of ultrashort spin current pulses injected in semiconductors

Ultrashort spin current pulses have great potential to become carriers of information in future ultrafast spintronics. They present the outstanding property of an extremely compressed time profile, which can allow for the building up of spintronics operating at the unprecedented THz frequencies. The ultrashort spin pulses, however, still lack other desirable features. For instance the spatial profile resembles more that of a spill rather than that of a spatially compressed pulse. Moreover the ultrashort spin current pulses can travel only across small distances in metals. The injection of the ultrashort spin pulses from the metallic ferromagnet, where they have to be generated, into a semiconductor is proposed as the first step to overcome both issues by allowing the excited electrons to propagate in a medium with few scatterings. However designing efficient interfaces for the injection is challenging due to practical constraints like chemical and structural stability. This work therefore expands the study of injection to a broader range of interfaces, and analyses how different metallic layers and semiconductors influence the amplitude, the spin polarisation and duration of the ultrashort pulses. This provides guidelines for the selection of efficient interfaces and, equally importantly, experimentally testable trends.

Long-term tests duration reduction for PEMFC μ-CHP application

Proton exchange membrane fuel cells (PEMFC) are extremely promising devices. Nevertheless some technological constraints concerning system durability and reliability costs, still limit their large-scale production. In this framework, lifetime prediction and durability enhancement studies are mainly concerned. To solve this issue, methods based on Prognostic and Health Management (PHM) are developed. It is worth noting that these methods usually require to establish a consistent database concerning the system ageing referring to specific mission profiles. To this purpose, long-term tests are commonly performed. Among different applications, this paper will focus on two micro-cogeneration (μ-CHP) durability tests, based on the same load demand. The first test is realized in 1000 h while the second one is reduced to 500 h resulting in a compressed profile. We observed that the respective global voltage degradation rates are similar. Consequently a reflection is proposed to support accelerated tests protocol development.

Ionization compression impact on dense gas distribution and star formation

Ionization feedback should impact the probability distribution function (PDF) of the column density around the ionized gas. We aim to quantify this effect and discuss its potential link to the Core and Initial Mass Function (CMF/IMF). We used in a systematic way Herschel column density maps of several regions observed within the HOBYS key program: M16, the Rosette and Vela C molecular cloud, and the RCW 120 H ii region. We fitted the column density PDFs of all clouds with two lognormal distributions, since they present a double-peak or enlarged shape in the PDF. Our interpretation is that the lowest part of the column density distribution describes the turbulent molecular gas while the second peak corresponds to a compression zone induced by the expansion of the ionized gas into the turbulent molecular cloud. The condensations at the edge of the ionized gas have a steep compressed radial profile, sometimes recognizable in the flattening of the power-law tail. This could lead to an unambiguous criterion able to disentangle triggered from pre-existing star formation. In the context of the gravo-turbulent scenario for the origin of the CMF/IMF, the double peaked/enlarged shape of the PDF may impact the formation of objects at both the low-mass and the high-mass end of the CMF/IMF. In particular a broader PDF is required by the gravo-turbulent scenario to fit properly the IMF with a reasonable initial Mach number for the molecular cloud. Since other physical processes (e.g. the equation of state and the variations among the core properties) have already been suggested to broaden the PDF, the relative importance of the different effects remains an open question.

Are low-skill public sector workers really overpaid? A quasi-differenced panel data analysis

Public–private sectoral wage differentials have been studied extensively using quantile regression techniques. These typically find large public sector premiums at the bottom of the wage distribution. This may imply that low skill workers are ‘overpaid’, prompting concerns over efficiency. We note several other potential explanations for this result and explicitly test whether the premium varies with skill, using Australian data. We use a quasi-differenced Generalized Method of Moments (GMM) panel data model which has not been previously applied to this topic, internationally. Unlike other available methods, this technique identifies sectoral differences in returns to unobserved skill. It also facilitates a decomposition of the wage gap into components explained by differences in returns to all (observed and unobserved) skills and by differences in their stock. We find no evidence to suggest that the premium varies with skill. One interpretation is that the compressed wage profile of the public sector induces the best workers (on unobserved skills) to join the public sector in low wage occupations, vice versa in high wage occupations. We also estimate the average public sector premium to be 6% for women and statistically insignificant (4%) for men.

Effects of errors in velocity tilt on maximum longitudinal compression during neutralized drift compression of intense beam pulses: I. general description

Neutralized drift compression offers an effective means for particle beam pulse compression and current amplification. In neutralized drift compression, a linear longitudinal velocity tilt (head-to-tail gradient) is applied to the non-relativistic beam pulse, so that the beam pulse compresses as it drifts in the focusing section. The beam current can increase by more than a factor of 100 in the longitudinal direction. We have performed an analytical study of how errors in the velocity tilt acquired by the beam in the induction bunching module limit the maximum longitudinal compression. It is found that the compression ratio is determined by the relative errors in the velocity tilt. That is, one-percent errors may limit the compression to a factor of one hundred. However, a part of the beam pulse where the errors are small may compress to much higher values, which are determined by the initial thermal spread of the beam pulse. It is also shown that sharp jumps in the compressed current density profile can be produced due to overlaying of different parts of the pulse near the focal plane. Examples of slowly varying and rapidly varying errors compared to the beam pulse duration are studied. For beam velocity errors given by a cubic function, the compression ratio can be described analytically. In this limit, a significant portion of the beam pulse is located in the broad wings of the pulse and is poorly compressed. The central part of the compressed pulse is determined by the thermal spread. The scaling law for maximum compression ratio is derived. In addition to a smooth variation in the velocity tilt, fast-changing errors during the pulse may appear in the induction bunching module if the voltage pulse is formed by several pulsed elements. Different parts of the pulse compress nearly simultaneously at the target and the compressed profile may have many peaks. The maximum compression is a function of both thermal spread and the velocity errors. The effects of the finite gap width of the bunching module on compression are analyzed analytically.

Selecting Valid Correlation Areas for Automated Bullet Identification System Based on Striation Detection.

Some automated bullet identification systems calculate a correlation score between two land impressions to measure their similarity. When extracting a compressed profile from the land impression of a fired bullet, inclusion of areas that do not contain valid individual striation information may lead to sub-optimal extraction and therefore may deteriorate the correlation result. In this paper, an edge detection algorithm and selection process are used together to locate the edge points of all tool-mark features and filter out those not corresponding to striation marks. Edge points of the resulting striation marks are reserved and expanded to generate a mask image. By imposing the mask image on the topography image, the weakly striated area(s) are removed from the expressed profile extraction. Using this method, 48 bullets fired from 12 gun barrels of six manufacturers resulted in a higher matching rate than previous studies.

Light control on phytoplankton production in a shallow and turbid estuarine system

Tagus estuary is one of the largest estuaries of Western Europe. With the aim of unravelling the drivers of primary production in this shallow and turbid nutrient replete estuary, we tested the hypothesis that light availability is a major factor controlling phytoplankton production. Environmental parameters, phytoplankton biomass, community composition, and photosynthetic parameters were monitored at two sites in the estuary during a complete annual cycle. Despite the fact that nutrient concentrations were always above growth-limiting values, Chl a concentrations were relatively low throughout the study period. High water column turbidity, due to riverine inputs, promoted a rapid attenuation of light and created a compressed profile with optimal photosynthetic conditions. Therefore, the phytoplankton community, dominated by small cells, such as diatoms and cryptophycean flagellates, displayed highly photosynthetic efficiency and low light-saturated photosynthetic rates as a photo-acclimation response to low light conditions year-round. Primary production rate was unimodal, peaking in the summer months. In such estuarine system, gross primary production could thus be predicted by an existing robust empirical model based on pigment standing crop (Chl a), surface irradiance (E 0) and optical depth (Z eup). Compared to other shallow estuaries, the Tagus can be classified as a low- to moderately productive estuary, being the turbidity-induced low light conditions the principal factor limiting phytoplankton growth.

Ultrastructure and potential taxonomic importance of euspermatozoa and paraspermatozoa in the volutid gastropods Zidona dufresnei and Provocator mirabilis (Caenogastropoda, Mollusca)

The ultrastructure of mature spermatozoa is investigated for the first time in the Volutidae, based on the commercially significant South American species Zidona dufresnei (Donovan, 1823) (fresh material) and supplemented with observations on testicular (museum) material of the deep sea New Zealand species Provocator mirabilis (Finlay, 1926). Euspermatozoa of Z. dufresnei (ex sperm duct) consist of: (1) a tall-conical acrosomal vesicle (with short basal invagination, constricted anteriorly) which is flattened anteriorly and associated with an axial rod, centrally perforate basal plate and short accessory membrane; (2) a rod-shaped, solid and highly electron-dense nucleus (with short basal fossa containing centriolar complex and initial portion of a 9 + 2 axoneme); (3) an elongate midpiece consisting of the axoneme sheathed by 5–6 helical mitochondrial elements, each exhibiting a dense U-shaped outer layer; (4) an elongate glycogen piece (axoneme sheathed by nine tracts of putative glycogen granules); (5) a dense annulus at the junction of the midpiece and glycogen piece and (6) a short free tail region (axoneme surrounded only by plasma membrane). Paraspermatozoa of Z. dufresnei are vermiform and dimorphic: the first type contains approximately 14–20 axonemes (arranged peripherally and interspersed with microtubules) and numerous oblong dense vesicles, numerous less dense (round) vesicles, occasional, large lipid-like vesicles, and scattered mitochondria; the second type contains 25–31 axonemes (peripherally arranged, interspersed with microtubules), occasional mitochondria and extensive cytoplasm. Results obtained for P. mirabilis from testis material are essentially as observed in Z. dufresnei, although the euspermatozoan acrosome still has to achieve its compressed transverse profile. Observations on paraspermatozoa were limited by fixation quality of available (testis) tissues, but these cells are similar to the first type of Zidona paraspermatozoa. Although most of the euspermatozoal features are also observed in many neotaenioglossans and neogastropods, the U-shaped outer layer of each mitochondrial element has not previously been reported and may prove a diagnostic feature of the Volutidae, the subfamily Zidoniinae or possibly only the Zidonini (in which Z. dufresnei and P. mirabilis are currently placed).

Pulse Compression Using Direct Feedback of the Spectral Phase From Photonic Crystal Fiber Output Without the Need for the Taylor Expansion Method

Characterization and compensation of the complex spectral phase and the temporal profile of output pulses from a photonic crystal fiber (620-945-nm spectral broadening) were performed using a computer-controlled feedback system that combines a modified spectral-phase interferometry for direct electric-field reconstruction apparatus and only a 4-f chirp compensator having a spatial light modulator. These pulses were adaptively compressed from 12-fs input pulses to 6.8-fs. In addition, the compressed pulse profile showed excellent agreement with results measured independently with fringe-resolved autocorrelation.

Rapid profiling via stratified sampling

Sophisticated binary translators and dynamic optimizers demand a program profiler with low overhead, high accuracy, and the ability to collect a variety of profile types. A profiling scheme that achieves these goals is proposed. Conceptually, the hardware compresses a stream of profile data by counting identical events; the compressed profile dam is passed to software for analysis. Compressing the high-bandwidth event stream greatly reduces software overhead. Because optimizations can tolerate some profiling errors, we allow the stream compressor to be lossy, thereby enabling a low-cost sampling-based hardware design. Because the hardware compressor is insensitive to the event content, it supports various profile types and can process multiple types simultaneously. Basic components of our framework are periodic and random samplers, counters, and hash functions. These components are composed to form a variety of stream compressors. One design is both simple and very effective: the input stream is hash-split into multiple substreams, each of which is fed into a simple periodic sampler that selects every kth event. This stratified periodic sampler performs better than conventional random sampling because it biases each substream towards a small number of unique events, thereby reducing sampling error, and allowing faster convergence to an accurate profile. For example, convergence to a given level of accuracy is about twice as fast for gcc. When sampling overhead is considered, the stratified periodic profiler achieves less than 3% error while incurring an overhead of only 3.5% for gcc.

Diffuse Illumination as a Default Assumption for Shape-From-Shading in the Absence of Shadows

Sinusoidal luminance patterns appear dramatically saturated toward the brighter regions. The saturation is not perceptually logarithmic but exhibits a hyperbolic (Naka&#x2013;Rushton) compression behavior at normal indoor luminance levels. The object interpretation of the spoke patterns is not consistent with the default assumption of any unidirectional light source but implies a diffuse illumination source (as if the object were looming out of a fog). The depth interpretation is, however, consistent with the hypothesis that the compressed brightness profile provided the neural signal for perceived shape, as an approximation to computing the diffuse Lambertian illumination function for this surface. The surface material of the images is perceived as non-Lambertian to varying degrees, ranging from a chalky matte to a lustrous metallic.

Automatic EEG analysis during long-term monitoring in the ICU

To assist in the reviewing of prolonged EEGs, we have developed an automatic EEG analysis method that can be used to compress the prolonged EEG into two pages. The proposed approach of Automatic Analysis of Segmented-EEG (AAS-EEG) consists of 4 basic steps: (1) segmentation; (2) feature extraction; (3) classification; and (4) presentation. The idea is to break down the EEG into stationary segments and extract features that can be used to classify the segments into groups of like patterns. The final step involves the presentation of the processed data in a compressed form. This is done by providing the EEGer with a representative sample from each group of EEG patterns and a compressed time profile of the complete EEG. To verify the above approach, 41 6 h EEG records were assessed for normality via the AAS-EEG and conventional EEG approaches. The difference between the overall assessment via compressed and conventional EEG was within one abnormality level 100% of the time, and within one-half level for 73.6% of the records. We demonstrated the feasibility and reliability of automatically segmenting and clustering the EEG, thus allowing the reduction of a 6 h tracing to a few representative segments and their time sequence. This should facilitate review of long recordings during monitoring in the ICU.

Earth structure with a compressed profile: V. I. Astafichev, Hydrotechnical Construction, 28(10), 1995, pp 593–596; translated from: Gidrotekhnicheskoe Stroitel'stvo, (10), 1994, pp 17–19

Earth structure with a compressed profile: V. I. Astafichev, Hydrotechnical Construction, 28(10), 1995, pp 593–596; translated from: Gidrotekhnicheskoe Stroitel'stvo, (10), 1994, pp 17–19