Middle Channels Research Articles

Microchip Atmospheric Pressure Chemical Ionization Source for Mass Spectrometry

A novel microchip heated nebulizer for atmospheric pressure chemical ionization mass spectrometry is presented. Anisotropic wet etching is used to fabricate the flow channels, inlet, and nozzle on a silicon wafer. An integrated heater of aluminum is sputtered on a glass wafer. The two wafers are jointed by anodic bonding, creating a two-dimensional version of an APCI source with a sample channel in the middle and gas channels symmetrically on both sides. The ionization is initiated with an external corona-discharge needle positioned 2 mm in front of the microchip heated nebulizer. The microchip APCI source provides flow rates down to 50 nL/min, stable long-term analysis with chip lifetime of weeks, good quantitative repeatability (RSD < 10%) and linearity (r(2) > 0.995) with linear dynamic rage of at least 4 orders of magnitude, and cost-efficient manufacturing. The limit of detection (LOD) for acridine measured with microchip APCI at flow rate of 6.2 muL/min was 5 nM, corresponding to a mass flow of 0.52 fmol/s. The LOD with commercial macro-APCI at a flow rate of 1 mL/min for acridine was the same, 5 nM, corresponding to a significantly worse mass flow sensitivity (83 fmol/s) than measured with microchip APCI. The advantages of microchip APCI makes it a very attractive new microfluidic detector.

A numerical study on the contribution of melting layer composed by coated ice spheres to the upwelling brightness temperatures in TMI channels using VDISORT algorithm

To examine the influence of bright band on the retrieval of precipitation rate, the performance of melting layer composed by coated ice precipitable particles on the satellite-based measurement of polarized microwave brightness temperatures is discussed in this article by a vector discrete ordinate radiative transfer model. After comparing the simulated brightness temperatures in different TMI channels with and without the melting layer, we conclude that: (1) The melting layer composed by liquid-coated ice spheres weakens the upwelling microwave brightness temperatures because of the absorption/emission effect caused by the liquid coat. This effect is more conspicuous in middle and high frequency channels (19, 37 and 85 GHz) but, in 85 GHz channel, with the increase of rain rate, the multi-scattering can weaken its effect. (2) In a specific frequency, the horizontally polarized brightness temperature is more severely weakened by the melting layer than the vertically polarized. With the “cold” background (ocean surface, for example), this character is more conspicuous than that with a warm background. That is to say, the inner structure of a cloud system is easier to be detected under a cold background. Only in the 85 GHz frequency and when the rain rate is larger than 4 mm/h can we find that the vertically polarized brightness temperature is more severely weakened than the horizontally polarized one. (3) The melting layer with the assumption of coated ice spheres can change the difference of brightness temperatures between the vertically and horizontally polarized channels in the same frequency. In general, the value of such difference with the assumption of melting layer is larger than that without it. With a warm background, this value is negative and only in middle frequency (37 GHz), it is both stable and conspicuous.

Interactions between Topography and Channel Development from 3D Seismic Analysis: an Example from the Tertiary of the Flett Ridge, Faroe-Shetland Basin, UK

Abstract Interpretation of 3D and 2D seismic data in the Faroe-Shetland Basin (FSB) has revealed the important role that structurally controlled bathymetry had in controlling sedimentary dispersal during Early Cenozoic thermal subsidence. The Flett Ridge was a major NE-SW structural high during some of the Palaeogene, actively growing and influencing adjacent sedimentary systems. During the Palaeogene this area of the FSB was a key entry point for siliciclastic sediment with a major deltaic system prograding towards the NW during the Middle Eocene. Prior to delta development, the Flett Ridge was onlapped during the Late Palaeocene and subsequently blanketed and drowned in Early Eocene times. Major periods of fluvial incision cutting up to 100 m into the Middle Eocene strata are identified and a variety of channel networks with differing trends documented. Broad channels or valleys of earliest Middle Eocene age inherited the palaeotopography created by the Flett Ridge, whereas subsequent later Middle Eocene meandering channels trend perpendicular to the shelf edge and traverse the Flett Ridge structure. Seismic amplitude maps suggest that a complex and variable channelized drainage system developed across the coastal plain and delta top in the Middle Eocene. These channels influenced sediment supply creating an area of bypass to the more distal fan systems preserved at the base of slope. Later faulting on the ridge crest may also have affected the channel network pattern.

Spawning areas and early development of long spiky-head carp ( Luciobrama macrocephalus ) in the Yangtze River and Pearl River, China

The spawning areas and early development of long spiky-head carp, Luciobrama macrocephalus (Lacepede), an endemic fish species in China, were investigated in the Yangtze River and Pearl River of central and southeastern China between 1961 and 1993. The potamodromous fish migrated upstream to spawn between May and July as the floodwater began to rise. The water-hardened eggs drifted down the river, and the embryos and larvae developed in the course of drifting. The spawning areas of the fish were widely found in the upper and middle main channels and large tributaries. Two large dams (Gezhouba dam and Danjiangkou dam) did not significantly impact on the reproduction of the fish. Fifty stages of the early development from one cell to the juvenile with fully formed fins were observed and characterized pictorially. The larvae of long spiky-head carp could be distinguished from the larvae of other co-occurring species by counting the number of somites and comparing the proportion of sizes of eye to otic capsule.

Hydraulic and morphological characteristics of middle and upper reaches of the Paraná River (Argentina and Brazil)

The Paraná River basin is a 2,600,000-km 2 South American fluvial system, most of which is in Brazil and Argentina. The channel is about 4000 km long, the mean annual discharge is 17,000 m 3 s −1, and the annual sediment load is more than 150,000,000 tons. The basin of the Paraguay River, its main tributary, covers about 38% of the Paraná basin. This paper compares the upper and middle channels of the Paraná. Hydraulic, morphological and sedimentological features of the Paraná River upstream and downstream of the confluence with the Paraguay were analyzed in order to evaluate the changes in these variables. The effect of the Paraguay on water and suspended sediment discharges was examined. The Paraguay River contribution explains most of the variation in channel conditions upstream and downstream of the confluence. The channel pattern, however, remains braided. The high bed load of the Paraná River in proportion to the total sediment discharge (21% in the upper course, 25% in the middle course) determines the similarity in drainage.

Physiography and recent sediment distribution of the Celtic Deep-Sea Fan, Bay of Biscay

The Celtic Deep-Sea Fan located in the northwestern part of the Bay of Biscay is a middle sized fan with a surface area of more than 30,000 km 2 . The whole system is a mature mud/sand-rich submarine fan on a passive margin. Multi-beam echo sounder data, 3.5 kHz seismic and 12 Kullenberg cores were examined to define the fan morphology, the lithological characteristics, the sedimentary processes and the relationship between the evolution of the fan deposits and the environmental conditions on the Celtic continental shelf. The upper fan is characterised by the presence of two distinct tributary systems: (1) the Whittard system with a large, persistent, slightly sinuous channel, which is linked to the southern end of the Irish Sea River system; and (2) the Shamrock system, with a moderate sized channel, which is linked to the western end of the English Channel River system. The middle and lower fan corresponds to divergent braided secondary channels and associate lobes. Successive lobe elements, without impor- tant relief, were generated during periodic avulsions of middle fan channels. The lithological, palaeontological, and geochemical analyses on cores show the evolution of sedimentation since the last glaciation. During the last lowstand and rise of sea-level frequent low-density turbidity currents were predominant and deposited sediments throughout the whole fan system. They were initiated at the front of a deltaic environment on the Celtic outer-shelf. During the high sea-level conditions, occasional high-density turbidity currents and/or non-cohesive debris flows occur and were responsible for sand deposition in the middle-lower fan. They are derived from reworked sands due to the high- energy conditions on the outer shelf. Thus for the Celtic Fan, the variations of the hydrodynamic conditions on the outer Celtic Shelf seem to be the primary control on facies shift and fan growth. q 2000 Elsevier Science B.V. All rights reserved.

A new approach for the detection of major fires caused by industrial accidents, using NOAA/AVHRR imagery

The Advanced Very High Resolution Radiometer (AVHRR) on board the NOAA satellites may be used to detect major fires caused by industrial accidents through the combined use of middle (3.55-3.93 mum) and thermal infrared (10.5-11.3 mum, 11.5-12.5 mum) channels. An algorithm was developed to identify the pixels which correspond to the sites of the industrial accidents where a major fire had developed. The algorithm was applied for two industrial accidents; Lyon, France on 2 June 1987 and Kalohori, Greece on 24 February 1986. The algorithm was based on the analysis of the differences between the brightness temperatures resulting from Channels 3 (3.55-3.93 mum) and 4 (10.5-11.3 mum) of AVHRR and of two masking filters for clouds. The first filter takes advantage of the information provided by Channels 1 (0.58-0.68 mum) and 5 (11.5-12.5 mum) of AVHRR, whereas the second introduces a threshold value for cloud top temperature. The use of the algorithm for the selected industrial accidents demonstrates its capability to detect major fires.

System design and performance of reconfigurable and simultaneous 2D multiple-plane WDM optical interconnects

A system design for reconfigurable and simultaneous 2D multiple-plane WDM optical interconnects has been investigated. Device characteristics such as detector responsivity shape, efficiency, and complexity affect the design requirements for wavelength separation and channel power. With decreasing wavelength separation, increased optical crosstalk and signal power loss result in performance penalties most notably for the middle wavelength channels. When signal power loss and optical crosstalk from the detection of undesired channels are evaluated, it is found that wavelength channel spacing down to 10 nm can be tolerated for the specific detector responsivity shape and efficiency attainable from currently available devices.

Texture analysis and classification with tree-structured wavelet transform

A multiresolution approach based on a modified wavelet transform called the tree-structured wavelet transform or wavelet packets is proposed. The development of this transform is motivated by the observation that a large class of natural textures can be modeled as quasi-periodic signals whose dominant frequencies are located in the middle frequency channels. With the transform, it is possible to zoom into any desired frequency channels for further decomposition. In contrast, the conventional pyramid-structured wavelet transform performs further decomposition in low-frequency channels. A progressive texture classification algorithm which is not only computationally attractive but also has excellent performance is developed. The performance of the present method is compared with that of several other methods.

Nuevos aportes al conocimiento de los Oligoquetos del Rio Paraná Medio y algunos tributarios

This paper treats the Oligochaeta species found in the benthos of lotic, environments of the Middle Parana River, secondary channels and tributaries (29° 10’ S ‐ 59° 15’ W and 32°00’ 60°40’ W). Nineteen species of Naididae, Tubificidae, Opistocystidae, Haplotaxidae and Lumbricidae are reported. A comparative analysis of setal morphology and number for the Naididae is provided. Slavina appendiculata is redescribed, and new records from Argentina noted. Dero (Aulophorus) aff. gravelyi, Dero (Dero) palmata and Nais, bretscheri are newly recorded for South America.

Depositional Environments of Lower Cretaceous McMurray Formation, Athabasca Oil Sands, Alberta

Most of the bitumen resources in the Athabasca oil sands deposit are contained in upward-fining channel sands of the Lower Cretaceous McMurray Formation. The channels were part of a northward-flowing fluvial drainage system that was being encroached upon by the rising Clearwater Sea. The lower member of the formation, present only in the deepest valleys on the underlying Devonian limestone surface, is dominantly fluvial in character. Rising sea level during middle member deposition resulted in a decreased gradient and a change from the shallow (5-10 m or 15-30 ft), commonly coarse-grained channels of the lower member to the deep (20-30 m or 65-100 ft), narrow, sinuous, high suspended-load channels of the middle member. Although there is evidence for some marine influence in the middle member channels, the processes of channel formation appear to be dominantly fluvial. In off-channel areas of the middle member, rising sea level resulted in the development of widespread subaqueous conditions and rapid vertical aggradation. Thick sequences of mud accumulated in lacustrine and brackish-bay environments that existed contemporaneously with the channels. Coal beds and rooted zones, common in the lower and upper members, are notably absent from the middle member. The upper member of the McMurray Formation was deposited during a time of slower aggradation and increased marine influence. It is characterized by smaller scale sedimentation units, commonly small upward-coarsening sequences interpreted as splay deposits of nearby large channels. In northern and western parts of the study area, open-marine conditions existed in upper member time, and upward-coarsening, offshore marine bar sands developed at the top of the formation.

Two Types of Outer Fan Lobe Sequence, from the Late Precambrian Kongsfjord Formation Submarine Fan, Finnmark, North Norway

ABSTRACT A comparison of outer fan sections from different parts of the Kongsfjord Formation Submarine Fan has revealed two types of outer fan lobe sequence, designated Type I and Type II. Both types of lobe sequence contain lobes, including lobe fringe deposits, that are between 2 m and 15 m thick, although Type I lobes are generally less than 10 m thick; there are no obvious differences in bed thickness, grain size, or other sedimentary attributes. The distinction between Type I and Type II lobes is based primarily upon their vertical frequency within fan fringe deposits. Type I lobes are separated by lobe fringe plus fan fringe deposits of similar thickness; therefore, in vertical sections the lobes are regularly spaced. Type II lobes occur sporadically within sections where lobe fringe plu fan fringe deposits vary from tens of centimeters to 70 m. In the two representative sections that illustrate the typological differences, Type I lobes, plus lobe fringe deposits, comprise 60 percent of the section, compared to 22 percent for the Type II lobe sequences. Type I lobe sequences are interpreted as the result of regular lobe switching immediately downfan from the middle fan channels, within a relatively proximal outer fan environment. Type II lobe sequences are interpreted as a consequence of sporadic progradation of lobes in a relatively distal fan environment that usually received fan fringe sedimentation. Type I lobes represent regular and stable deposition controlled by intrafan (intrabasinal) processes, whereas Type II lobes developed because of relatively catastrophic intrafan (e.g., major channel relocation) or extrafan (source control) processes. This distinction may serve as a proximality indicator in outer fan successions.

Dipmeter and Log Motifs in North Sea Submarine-Fan Sands

Submarine-fan sands and conglomerates are common in the North Sea basin, ranging in age from Middle Jurassic to early Eocene. Many ancient submarine fans are important reservoirs, both there and in rocks of diverse ages in other parts of the world. Deep-sea facies may be identified from seismic data, if they can be seen to occur at the foot of progradational delta slopes or fault scarps, and if submarine channel and fan morphologies can be mapped. They may also be identified from the sedimentologic study of cores. Once identified, the geometry and orientation of reservoirs in deep-sea deposits can be predicted from dipmeter and other wireline logs. In the North Sea, three basic log motifs can be recognized. (1) Slope and upper fan grain-flow sands and mass-flow conglomerates on gamma-SP logs show uniform motifs with sharp upper and lower contacts; dips are random. (2) Middle fan turbidite-infilled channels on gamma-SP logs show increased shale upward in section, serrate motif; dip motif declines upward, dipping into channel axis. (3) Lower fan turbidite lobes on gamma ray-SP logs show increased sand upward in sections, serrate motif; dip motifs increase upward, dipping in direction of progradation.

Mobility and the Middle Class Extended Family

The paper reports the findings of intensive research on 120 middle class families. The geographical distribution of the members of the extended family was wider, and contact between them was less frequent than among the middle class families sampled by previous authors. In these seemingly adverse conditions the middle class extended family was nevertheless a functioning social entity. The relationship between the head of a household and his father or father-in-law was found to be frequently of great importance. It is by means of this link that the elder middle class generation channels financial aid to the next generation. This aid enhances the living standard of the recipients. It is an aspect of social mobility overlooked by studies concentrating upon occupational mobility.