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Abstract Air classifier mill (ACM) is widely used in powder coating and mineral comminution process. One of the problems typically presenting in ACM is over-grinding, which leads to high energy consumption and broad particle size distribution (PSD). To decrease the excessive amount of fine particles in the products, 6 configurations of grinding pins with ditches in the impact surface were used in the experiments. The width and depth of ditches varied from 1.35 mm and 1 mm to 4.75 mm and 3 mm, respectively, while the interior angles in the ditches are the same. The particle size and PSD show that the ditches on the grinding pins have significant effect on the D 10 values and the particle size span. The deepest and widest ditches (P4) result in largest D 10 and smallest span in this study. The D 10 s of products ground by P4 increase by 24.1% for fine powder (D 50 = 25 μm) and 16.0% for coarse powder (D 50 = 33 μm), while the span decreases by 6.9% (D 50 = 25 μm) and 6.4% (D 50 = 33 μm) compared to regular cylindrical pins (PC), respectively. Meanwhile, it is found that the P4 configuration improves the energy utilization efficiency by 7.6% (D 50 = 25 μm) and 3.4% (D 50 = 33 μm), compared to that of the original PC pins. Graphical abstract Unlabelled Image Highlights • The paper presents an efficient way to reduce over-grinding of ACM. • The method involves modification of ACM pin, especially the impact surface. • The method increases the D 10 and decrease the span of the ground powder. • The modification leads to the reduction of the average specific energy consumption. [ABSTRACT FROM AUTHOR]

Abstract Coquinas are important carbonate oil reservoirs in the sin-rift sequence of the Brazilian marginal basins, mainly in Campos and Santos basins. They are generated from shell accumulations in lake-margin environments in which waves and bottom currents, at storm conditions, were the main hydrodynamic agents of transport and reworking. In order to investigate the role of wave transformation processes in shallow waters – swash, breaking and wave shoaling – in shell concentrations, a physical modelling of the coastal environment was performed in laboratory. The experimental setup consisted of a 2D flume, a wave generator, and a sedimentary bottom composed by quartz sand and shells (bivalves, gastropods, and fragments). An underwater camera, wave gauges and an ADV were used to record the sedimentary processes and to perform a quantitative analysis of the hydrodynamics. The experimental scenario reproduced a rift-lake margin. A coastal sector of Lake Tanganyika, Tanzania, Africa, was used to set the model boundary conditions (in a 1/20 scale) as well as the coastal gradient and wave conditions. From 54 h of wave experiments which alternated from fair-weather to storm wave conditions, three shell concentration dynamics were observed: reworking, winnowing, and dynamic bypassing. The reworking (erosion) was characterized by traction, rolling, and saltation of bioclasts, together with the traction and suspension of sand. The occurrence of the latter was restricted to the breaking and swash zone in both fair-weather and storm conditions. The winnowing (erosion) was featured by sand suspension and the gentle traction and rotation of the bioclasts on the bottom. The winnowing occurred at the proximal area of the shoaling zone, just behind the first wave-breaking point in storm wave conditions. The dynamic bypassing (omission) was identified by the ripples migration over static shells on the bottom of the distal shoaling zone, which produced alternated burial and exhumation of bioclasts. The quantitative analysis of the oscillatory flow indicated higher velocities at the breaking zone (reworking domain) than at the shoaling zone (winnowing domain) mainly during storm conditions. This study provided new and more accurate insights to depositional models of lake-margin coquinas, suggesting that each wave transformation process control a specific dynamic of shell concentration. Also, the limit between the breaking zone and the shoaling zone in storm conditions (1st wave-breaking point), was identified as a better criterion to bound the reworking domain, where fragmented coquinas are produced, from the winnowing and dynamic bypassing domains, where non-fragmented coquinas occur, in contrast to the fair-weather wave base criterion. [ABSTRACT FROM AUTHOR]

Purpose Appraisal of records to separate the wheat (records of enduring value) from the chaff (ephemeral records) is one of the most important functions of the archives. In terms of the National Archives and Records Service of South Africa (NARSSA) Act (No. 43 of 1996) (the Act), “no public records may be transferred to an archives repository, destroyed, erased or otherwise disposed of without the written authorisation of the national archivist”. In implementing this section of the Act, the NARSSA issues a disposal authority, which emanates from the appraisal process explained in the policy guidelines of 2002. The purpose of the study is to analyse the appraisal policy guidelines on the approach of NARSSA in relation to preservation of digital records.Design/methodology/approach This study has used qualitative data obtained through content analysis and literature to review the appraisal policy guidelines and approach of NARSSA in relation to preservation of digital records. The 2002 approved appraisal policy, as well as the directives issued by NARSSA in terms of Section 13(4) of the Act, is examined to determine the criteria, the process and the methodology adopted in the appraisal of records. Content analysis data are augmented through interviews conducted in person with the head of the records management unit at NARSSA and the archivist responsible for appraisal of government records.Findings The study has established that, in terms of the approach, records are appraised two years after the implementation of records classification systems in governmental bodies and those of archival value are then transferred to an archives repository after a period of 20 years. Twenty years is a long period as records might be lost, especially in digital environments. Furthermore, the appraisal policy guidelines limit the powers of records managers in governmental bodies in deciding on records of enduring value, as this responsibility is assigned to archivists at NARSSA. It is clear that the policy was written with paper records in mind.Research limitations/implications This study may go a long way in influencing policy review to embrace appraisal of digital records in South Africa. This in turn will help in determining the feasibility of preservation technology for digital records.Originality/value This study is useful to ensure participation of the public in the appraisal process. This study has triangulated content analysis data with interviews to examine appraisal criteria, process and methodology, followed by NARSSA. [ABSTRACT FROM AUTHOR]

In developing countries, during the harvest season, winnower blade injuries occur very frequently in children and results in lifelong disability. Nine children were managed during 1 month, all resulting due to winnower blade induced craniofacial trauma. PubMed search for "fan blade injury" showed two case series and three case reports. In our study, 88% had compound depressed fracture; brain matter leak in 56%, cerebrospinal fluid (CSF) leak alone in 22%. 66.7% had injury involving the frontal bone. Two patients had eye injury with visual loss. Seven underwent debridement craniectomy, five augmentation duroplasty and three contusectomy. All had vegetable material, sand particles. Complications in 66.6% with two cases of CSF leak settled with lumbar drain, one case of CSF otorrohea, 22.2% of wound infection, 44.4% wound dehiscence requiring redebridement and suturing in five patients. Two patients had postoperative seizures, two patients had hemiparesis both improved. Two low Glasgow Coma Scale remained so on postoperative period. One case of subdural empyema needed debridement and duroplasty with glue. No mortality noted. These findings were consistent with previous reports. Follow-up at 1.5 months showed good functional recovery. Early surgery debridement, steps to minimize postoperative infections, identifying putative risk factors early in the management are the principles of a successful treatment regimen. [ABSTRACT FROM AUTHOR]

Motivation: The minimizers scheme is a method for selecting k-mers from sequences. It is used in many bioinformatics software tools to bin comparable sequences or to sample a sequence in a deterministic fashion at approximately regular intervals, in order to reduce memory consumption and processing time. Although very useful, the minimizers selection procedure has undesirable behaviors (e.g. too many k-mers are selected when processing certain sequences). Some of these problems were already known to the authors of the minimizers technique, and the natural lexicographic ordering of k-mers used by minimizers was recognized as their origin. Many software tools using minimizers employ ad hoc variations of the lexicographic order to alleviate those issues. Results: We provide an in-depth analysis of the effect of k-mer ordering on the performance of the minimizers technique. By using small universal hitting sets (a recently defined concept), we show how to significantly improve the performance of minimizers and avoid some of its worse behaviors. Based on these results, we encourage bioinformatics software developers to use an ordering based on a universal hitting set or, if not possible, a randomized ordering, rather than the lexicographic order. This analysis also settles negatively a conjecture (by Schleimer et al.) on the expected density of minimizers in a random sequence. [ABSTRACT FROM AUTHOR]

The objective of this study was to investigate the effect of physical characteristics of different size classes of J. curcas seeds on shelling performance using a modified disc mill. The seeds were grouped into four size classes using sieves with hole diameters of 8, 9, 10 and 12 mm. Length, breadth, width, arithmetic and geometric diameter, bulk and solid density, and surface area were significantly different at p ≤ 0.01. No significant differences were found in terms of sphericity and moisture content. Smaller seed size lead to higher porosity and percentage of shells. Rupture force was examined along length ( L ), width ( W ), and breadth ( B ) axes. A prototype of a disc mill was re-engineered and optimized. The preferential orientation of the seeds passing the mill was in the vertical direction. Optimum setting of rotational speed and aperture between the discs of the mill were strongly related to seed breadth. As the output fractions, dust, shells, fragmented kernels and full kernels could be separated pneumatically. Meanwhile, partially-shelled and unshelled seeds could only be separated manually by visual inspection. Under optimum conditions, the shelling efficiency for the four size classes was determined as 81.0, 83.5, 83.7, and 84.6%, respectively. Compared with results from unsorted seeds, pre-sorting the seeds significantly reduced the amount of partially-shelled and unshelled seeds at p ≤ 0.01. The maximum capacity of the machine was estimated as 131.5 kg/h which resulted in the lowest energy consumption of 0.002 kWh/kg. [ABSTRACT FROM AUTHOR]

ABSTRACT In aeolian sand sheets the interaction between aeolian and subaqueous processes is considered one of the principal factors that controls this depositional environment. To examine the role played by the subaqueous processes on the construction and accumulation of sand sheets, surface deposits and subsurface sedimentary sections of a currently active aeolian sand sheet, located in the Upper Tulum Valley (Argentina), have been examined. On the sand sheet surface, airflows enable the construction of nabkhas, wind-rippled mantles (flattened accumulations of sand forming wind ripples), megaripples, and small transverse dunes. Subaqueous deposits consist of sandy current ripples covered by muddy laminae. The latter are generated by annual widespread but low-energy floods that emanate from the nearby mountains in the aftermath of episodes of heavy precipitations. Deposits of subaqueous origin constitute 5% of the accumulated sand sheet thickness. The construction of the sand sheet is controlled by meteorological seasonal changes: the source area, the San Juan river alluvial fan, receives sediment by thaw-waters in spring-summer; in fall-winter, when the water table lowers in the alluvial fan, the sediment is available for aeolian transport and construction of the sand sheet area. The flood events play an important role in enabling sand sheet accumulation: the muddy laminae serve to protect the underlying deposits from aeolian winnowing. Incipient cement of gypsum on the sand and vegetation cover acts as an additional stabilizing agent that promotes accumulation. Episodic and alternating events of erosion and sedimentation are considered the main reason for the absence of soils and palaeosols. Results from this study have enabled the development of a generic model with which to account for: (i) the influence of contemporaneous subaqueous processes on the construction and accumulation in recent and ancient sand sheets; and (ii) the absence of developed soils in this unstable topographic surface. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Purpose: The geochemical compositions of sediments from three sectors in Trincomalee Bay (Koddiyar Bay, Thambalagam Bay and the Inner Harbour) in Sri Lanka were examined to determine fluvial and marine contributions and the effects of sorting and heavy mineral concentration. The present environmental status of the bay was also assessed. Materials and methods: Forty-nine sediment samples were collected from Trincomalee Bay and analysed by X-ray fluorescence, yielding data for the major elements and 17 trace elements. Mean grain size and sorting were also measured. Data were compared with the compositions of sediments from the lower Mahaweli River, which supplies most of the clastic detritus to Trincomalee Bay. Results and discussion: Sediments in the three sectors differ significantly in chemical composition, according to position relative to the Mahaweli River delta source, depositional environment, heavy mineral concentration and marine influences. According to accepted sediment quality guidelines, some As contamination may have occurred in the Inner Harbour and Thambalagam Bay and Cr contamination in all three sectors. Conclusions: Proximal Koddiyar Bay sediments compare closely with Mahaweli River bedload. Although the clastic component in the more distal Thambalagam Bay and the Inner Harbour is also derived from the Mahaweli River, compositions are modified significantly by marine contributions. High concentrations of elements including Ti, Zr, Ce, Nb and Y in NW Koddiyar Bay are consistent with heavy mineral concentration by winnowing in high-energy zones. Some decoupling of Fe-Ti- and Zr-bearing heavy mineral assemblages may occur within the bay. Al-normalized metal enrichment factors and contour maps show that apparent contamination by As and Cr is spurious and is caused by locally high background levels from Mahaweli River detritus. This illustrates the importance of establishing local background levels of elements during environmental studies. [ABSTRACT FROM AUTHOR]

Today, with the fast development of extensible markup language (XML) and increasing amount of data that is published in the form of XML, copyright protection of these data is becoming an important requirement for numerous applications. This study is proposing a system that uses fingerprinting to trace illegal copies and detect any modification made to an XML data. However, the flexible construction of XML data poses a number of challenges to fingerprinting, such as reorganisation and alteration. To overcome these challenges, the proposed system has to be based on the winnowing theory, which selects fingerprint from hashes of XML elements. This system is distortion free since it does not introduce any deformation to the XML data and also preserves usability constraint that is not optimised by the current fingerprinting systems. Experimental results show that the probability of missing fingerprint matching is very low and the chance to detect and locate changes in the XML data is very high. [ABSTRACT FROM AUTHOR]

Rare mutations in cell populations are known to be hallmarks of many diseases and cancers. Similarly, differential DNA methylation patterns arise in rare cell populations with diagnostic potential such as fetal cells circulating in maternal blood. Unfortunately, the frequency of alleles with diagnostic potential, relative to wild-type background sequence, is often well below the frequency of errors in currently available methods for sequence analysis, including very high throughput DNA sequencing. We demonstrate a DNA preparation and purification method that through non-linear electrophoretic separation in media containing oligonucleotide probes, achieves 10,000 fold enrichment of target DNA with single nucleotide specificity, and 100 fold enrichment of unmodified methylated DNA differing from the background by the methylation of a single cytosine residue. [ABSTRACT FROM AUTHOR]

This work presents results on riprap sizing for pile group protection against local scour. Shear failure mechanism is addressed, avoiding edge, bed-form undermining, and winnowing modes. The influences of the flow conditions and the distance between the piles are analyzed. As a result of a laboratory experimental campaign, and within a detailed dimensional analysis framework, the writers propose expressions for riprap block size to resist shear failure. The influence of the distance between the piles on the block size is shown to be small, and the proposed expressions compare well to some of the literature expressions for single piers. [ABSTRACT FROM AUTHOR]

High biogenic productivity, strong tidal currents, shoal topography, and short transport distances combine to favor shellbed formation along the lower flanks of a cape-associated shoal off Herod Point on Long Island, New York. This shell bed has a densely packed, clast-supported fabric composed largely of undegraded surf clam (Spisula solidissima) valves. It is widest along the central part of the western flank of the shoal where topographic gradients are steep and a stronger flood tide results in residual flow. The bed is narrower and thinner toward the landward margins where currents are too weak to transport larger valves and topographic gradients are gentle, limiting bed-load transport mechanisms by which the shells are concentrated. Reconnaissance mapping off Roanoke Point suggests that shell beds are also present at the other cape-associated shoals off northeastern Long Island, where relatively similar geomorphic and oceanographic conditions exist. These shell beds are important to the Long Island Sound ecosystem because they provide complex benthic habitats of rough and hard substrates at the boundary between the muddy basin floor and mobile sand of the shoals. [ABSTRACT FROM AUTHOR]

Abstract: An experimental study on the air-side heat transfer and pressure drop characteristics for brazed aluminum heat exchangers with multi-region louver fins and flat tubes was conducted. A series of tests were conducted for heat exchangers with different numbers of louver regions at the air-side Reynolds numbers of 400–1600 based on the louver pitch. The air-side thermal performance data were analyzed by using the effectiveness-NTU method. The characteristics of the heat transfer and pressure drop for heat exchangers with different geometry parameters were presented in terms of the Colburn j factor and Fanning friction f factor as function of the Reynolds number. [Copyright &y& Elsevier]

Abstract: Four commercial samples of distillers dried grains with solubles (DDGS) were sieved. All sieved fractions except for the pan fraction, constituting about 90% of original mass, were then winnowed with an air blast seed cleaner. Sieving was effective in producing fractions with varying composition. As the particle size decreased, protein and ash contents increased, and total carbohydrate (CHO) decreased. Winnowing sieved fractions was also effective in shifting composition, particularly for larger particle classes. Heavy sub-fractions were enriched in protein, oil and ash, while light sub-fractions were enriched for CHO. For protein, the combination of the two procedures resulted in a maximum 56.4% reduction in a fraction and maximum 60.2% increase in another fraction. As airflow velocity increased, light sub-fraction mass increased, while the compositional difference between the heavy and light sub-fractions decreased. Winnowing three times at a lower velocity was as effective as winnowing one time at a medium velocity. Winnowing the whole DDGS was much less effective than winnowing sieved fractions in changing composition, but sieving winnowed fractions was more effective than sieving whole DDGS. The two combination sequences gave comparable overall effects but sieving followed by winnowing is recommended because it requires less time. Regardless of combinational sequence, the second procedure was more effective in shifting composition than the first procedure. [Copyright &y& Elsevier]

Rotating wheel air classifiers are often used in many process industry applications. The internal geometry of these equipment is quite complicated and has not been investigated in detail. In the present study, the flow field inside a rotating wheel air classifier has been calculated using CFD techniques, taking full account of the internal geometrical features. The predicted overall flow rate and the flow pattern are in good agreement with measurements and flow visualization studies. The calculations show that the induced flow depends strongly on geometric parameters such as the location of the inlet and outlet ports and the type of shutters used. Trajectory calculations of single particles show that the particle motion is influenced principally by centrifugal force, air drag, and wall-rebound characteristics. The wall rebound is possibly one of the means of how large particles enter the fines stream, leading to low efficiency at high speeds or large particles. Experiments of the classification using angular and radial shutter vanes show distinct range of operability of each type. These results have been interpreted coherently in the light of the flow pattern and particle trajectory calculations. [ABSTRACT FROM AUTHOR]

In this paper, we give a mistake-bound for learning arbitrary linear-threshold concepts that are allowed to change over time in the on-line model of learning. We use a variation of the Winnow algorithm and show that the bounds for learning shifting linear-threshold functions have many of the same advantages that the traditional Winnow algorithm has on fixed concepts. These benefits include a weak dependence on the number of irrelevant attributes, inexpensive runtime, and robust behavior against noise. In fact, we show that the bound for tracking Winnow has even better performance with respect to irrelevant attributes. Let X ∈ [0, 1]′′ be an instance of the learning problem. In the previous bounds, the number of mistakes depends on ln n. In this paper, the shifting concept bound depends on maxln (||X||1). We show that this behavior is a result of certain parameter choices in the tracking version of Winnow, and we show how to use related parameters to get a similar mistake bound for the traditional fixed concept version of Winnow. [ABSTRACT FROM AUTHOR]

Discusses the use of specially made collection bags in the collection of seeds from a wide range of southeastern U.S. woodland species with diverse dispersal strategies. Separation of seeds from debris with a strainer after collection; Use of a fanning mill in cleaning the seeds; Putting of collection bags over stock plants in the nursery as seeds approach maturation.