Current Transport Processes Research Articles

Laminae Characteristics and Their Relationship with Mudstone Reservoir Quality in the Qingshankou Formation, Sanzhao Depression, Songliao Basin, Northeast China

Lamination is the predominant and widely developed sedimentary structure in mudstones. Similar to organic pores in shale gas reservoirs, the inorganic pores in the laminae of shale oil reservoirs are equivalently important high-quality reservoir spaces and flow channels. The laminae characteristics are strongly heterogeneous, being controlled by both deposition and diagenesis. However, the origin of this diversity is poorly understood. A detailed examination of cores, thin sections, and scanning electron microscopy analyses were conducted on the lacustrine mudstone of the Qingshankou Formation in the Songliao Basin to study the influence of deposition and diagenesis on laminae characteristics and their relationship to reservoir quality. Three types of laminae are mainly developed, namely thick siliceous laminae, thin siliceous laminae, and thin siliceous and argillaceous mixed laminae. Deposition controls the type and distribution of laminae. The thin siliceous and argillaceous mixed laminae are controlled by climate-driven seasonal flux variations. The thick siliceous laminae and thin siliceous laminae are controlled by bottom current or gravity-driven transport processes due to increased terrestrial input. The thin siliceous laminae have the optimum reservoir properties, followed by the thin siliceous and argillaceous mixed laminae, while the thick siliceous laminae have the worst properties. Diagenesis controls the pore evolution of the laminae. Different laminae have different paths of diagenesis. The thin siliceous laminae are mainly cemented by chlorite, preserving some primary porosity. The clay mineral content of the thin siliceous and argillaceous mixed laminae is high, and the primary pores are mainly destroyed by the strong deformation of the clay minerals during compaction. The thick siliceous laminae are intensely cemented by calcite, losing most of the porosity. The present study enhances the understanding of reservoir characteristics in laminae and provides a reference for shale oil exploration.

Analysis of photodiode and barrier properties of CoPc/n-Ge heterojunction under various illumination wavelengths

The present investigation reports the analysis of barrier parameters of the CoPc/n-Ge heterojunction photodiode under varied illumination wavelengths from 500 nm to 1200 nm in steps of 25 nm. The efficiency of this photodiode was also summarized using responsivity, detectivity and quantum efficiency for different illumination wavelengths. The photocurrent seems to be maximum for 850 nm and 1175 nm and shows higher responsivity of 1.72 A/W and 2.38 A/W at 775 nm and 1125 nm wavelength respectively. The quantum efficiency of the photodiode was found to be 275 % at illumination wavelength of 775 nm and 263 % at 1125 nm. For the selective illumination wavelengths (775 nm, 850 nm, 1125 nm and 1175 nm), the electrical properties of the CoPc/n-Ge photodiode were studied. Noticeable variation in the barrier parameters of the photodiode is observed with illumination than compared to dark. Significantly, the series resistance was found to be decreased and shunt resistance is increased with illumination wavelength than compared to dark. Current conduction mechanisms were also investigated in both the forward and reverse bias of the photodiode. The forward current transport processes show that at moderately high bias the current conduction might be associated with TCLC. It is also evidenced from the reverse conduction mechanism that at low reverse voltages PFE is found to be dominant whereas SE is dominant at high reverse voltages. The reduced interface state densities at the CoPc/n-Ge interface were observed under illumination than compared to dark.

Polarization-doped n-p-i-p-n GaN-based parallel phototransistor with thick GaN absorption layer for achieving high responsivity

In this report, we propose a polarization-doped n-p-i-p-n GaN-based parallel phototransistor with thick GaN absorption layer. We employ an Al-composition-graded AlxGa1–xN layer for achieving p-type doping feature. We have studied the light propagation in the unintentionally doped GaN (i-GaN) absorption layer with different thicknesses, and the optimized thickness is 2 μm. As a result, the photo current of 10−2 A cm−2 and the responsivity of 2.12 A W−1 can be obtained at the applied bias of 5 V. In our fabricated device, during the current transport process, the photo-generated carriers are not along the device surface. Therefore, the photoconductive effect will be absent, and hence our device achieves a response speed with a rise time of 43.3 ms and a fall time of 86.4 ms.

Annealing temperature effect on structural, electronic features and current transport process of Au/CoPc/undoped-InP MPS-type Schottky structure

The influence of annealing on structural, electronic features and the current transport process of the Au/CoPc/undoped-InP (MPS)-type structure is explored. Raman measurements of as-deposited CoPc thin films reveal significant vibrational bands at 593 cm−1, 682 cm−1 and 1537 cm−1 assigned to C-C and C-N band stretching, showing the structural confirmation of CoPc films. The surface topology of CoPc is assessed by AFM at various annealing temperatures. The roughness of CoPc films falls with rising annealing temperature up to 200 °C and then slightly rises after annealing at 300 °C and 400 °C. The electrical features of the MPS structure are explored by the I-V method and observed good rectification nature regardless of annealing temperatures. The mean barrier heights are estimated to be 0.76 eV, 0.89 eV, 0.91 eV, 0.86 eV and 0.85 eV for as-deposited, 100 °C, 200 °C, 300 °C and 400 °C by statistical distribution analysis. Results showed that the BHs increase as annealing rises to 200 °C and decrease after annealing at 300 °C and 400 °C. The derived series resistance of the MPS structure reduces with rising annealing up to 200 °C and then rises after annealing at 300 °C and 400 °C. The acquired density of states (NSS) of the MPS structure varied with annealing temperature may be the reduction in the recombination center and the prevalence of an interfacial layer between the CoPc and InP layers. Findings suggest that the PFE governs reverse current in the lower bias region, while, the SE ruled reverse current in the higher bias region of the MPS structure irrespective of annealing temperatures.

An in-depth investigation of gate leakage current degradation mechanisms in 1.2 kV 4H-SiC power MOSFETs

In this paper, a comprehensive study on the forward and reverse current degradation mechanisms in 1.2 kV planar SiC MOSFETs are investigated. With the help of Sentaurus TCAD simulations, numerical fitting method, step-bias stress, current-voltage (I-V) and capacitance-voltage (CV) experiments, we proposed defect-related transport models to describe the progression of gate leakage currents under forward and reverse high biases. It is found that, (1) trap-assisted tunneling (TAT) and Fowler-Nordheim (FN) tunneling dominate the forward low and high current transport process respectively. Moreover, the holes trapping is mainly responsible for the degradation of gate oxide and premature breakdown of SiC MOSFETs; (2) the reverse leakage current under high electric field is mainly carried by FN tunneling electrons, which lead to an increase of the intermediate localized states distributed in the SiC/SiO2 interface.

Digitalization in Maritime Transport and Seaports: Bibliometric, Content and Thematic Analysis

In this paper, a bibliometric, content and thematic analysis of digitalization in maritime transport and seaports was performed. The research was primarily motivated by the scarcity of similar works offering a comprehensive and recent literature analysis, the advancements of the maritime digitalization itself, and its influence on all related processes. The initial investigation phase considered 8178 publications, leading through the research steps to the final inclusion of 280 papers, the thematic and content analysis of which were performed using various bibliometric tools. The research encompassed various criteria, ranging through databases, keywords, topics, research areas and others. The resulting concept map emphasized the main concepts that digitalization in maritime transport relies on, or strives towards. The aim of the study was to address the fundamental research questions, with the tendency to define the main key points in the current maritime transport and seaport digitalization process. It can be concluded that an increasing number of authors recognize the importance of new digital technologies in maritime transport and seaports. However, with new digital technologies come specific risks such as spoofing or data manipulation that need to be further analyzed.

Nonvolatile modulation of spin transport in PMN-PT/LiFe5O8/Pt multiferroic heterostructures

Beside playing a keystone role in spin-field-effect transistor, electrical control of spin transport is also of fundamental and practical importance for many other spintronic devices due to the advantages of energy efficiency and versatility. In this work, we demonstrate a significant electrical modulation of spin transport in the PMN-PT/LiFe5O8/Pt heterostructures. The key spin transport parameters, including the spin Hall angle, spin diffusion length, and spin mixing conductance, were extracted through the thickness dependence of spin Hall magnetoresistance. It is found that the spin Hall angle decreases with the decrease in temperature, while the spin diffusion length keeps invariant with temperature, revealing the dominance of D'yakonov–Perel' type spin transport in LiFe5O8/Pt. Remarkably, by applying the electric field onto the piezoelectric PMN-PT substrate, the spin Hall angle of Pt can be modulated 28% and exhibits a nonvolatile hysteresis relationship with the applied electric field, which primarily originates from the modulation of Pt resistivity induced by the strain coupling through the ferroelastic domain switching of the ferroelectric PMN-PT substrate. Our results elucidate the spin transport characteristics in PMN-PT/LiFe5O8/Pt heterostructures and pave the way toward novel spintronic devices with electrically tunable spin current generation and transport processes.

CdTe X/γ-ray Detectors with Different Contact Materials.

Different contact materials and optimization of techniques of their depositions expand the possibilities to obtain high performance room temperature CdTe-based X/γ-ray detectors. The heterostructures with ohmic (MoOx) and Schottky (MoOx, TiOx, TiN, and In) contacts, created by DC reactive magnetron sputtering and vacuum thermal evaporation, as well as In/CdTe/Au diodes with a p-n junction, formed by laser-induced doping, have been developed and investigated. Depending on the surface pre-treatment of semi-insulating p-CdTe crystals, the deposition of a MoOx film formed either ohmic or Schottky contacts. Based on the calculations and I-V characteristics of the Mo-MoOx/p-CdTe/MoOx-Mo, In/p-CdTe/MoOx-Mo, Ti-TiOx/p-CdTe/MoOx-Mo, and Ti-TiN/p-CdTe/MoOx-Mo Schottky-diode detectors, the current transport processes were described in the models of the carrier generation–recombination within the space-charge region (SCR) at low bias, and space-charge limited current incorporating the Poole–Frenkel effect at higher voltages, respectively. The energies of generation–recombination centers, density of trapping centers, and effective carrier lifetimes were determined. Nanosecond laser irradiation of the In electrode, pre-deposited on the p-CdTe crystals, resulted in extending the voltage range, corresponding to the carrier generation–recombination in the SCR in the I-V characteristics of the In/CdTe/Au diodes. Such In/CdTe/Au p-n junction diode detectors demonstrated high energy resolutions (7%@59.5 keV, 4%@122 keV, and 1.6%@662 keV).

Disturbed climate changes preserved in terrigenous sediments associated with anthropogenic activities during the last century in the Taiwan Strait, East Asia

Accelerated human activity has greatly reduced sediment discharge into the global oceans in recent decades; however, the potential influence on climate change signals carried by sediments during source-to-sink transport processes remains poorly understood. To this end, multiple sedimentological analyses, including X-ray fluorescence scanning, grain-size composition, clay mineralogy, and 210Pb dating, of three short sediment cores retrieved from the Taiwan Strait, East Asia were performed. The results show that the terrigenous sediments of these cores spanning the last 150 years are mainly derived from the Yangtze River, with relatively small contributions from the Taiwan, Zhejiang, and Fujian rivers. The grain-size compositions are predominantly silt and clay (>90%), with minor sand, and the clay mineral assemblages consist of primarily illite, smectite, and chlorite, with moderate kaolinite. Both the clay mineral assemblage and grain-size compositions inferred from both end-member (EM) modeling and standard deviation analysis provide indirect indicators to reveal the East Asian monsoon variations, realized mainly through the current transport processes. The decreased smectite/(illite + chlorite) ratios since the 1850s represent a relatively long-term weakened East Asian winter monsoon (EAWM), while the overall decreased mean grain-size of the fine sensitive component and EM3/(EM1 + EM2) ratio during the 1850s–1950s also implies a gradually weakened EAWM associated with the synchronously weakened Zhe-Min Coastal Current. These sedimentary records of the East Asian monsoon variations can be compared with numerous published paleoclimate records. However, the largely increased mean grain-size of the fine sensitive component and EM3/(EM1 + EM2) ratios since the 1950s indicates a false strengthened EAWM signal, which conflicts with instrumental data and the clay mineralogy record. This observation, coupled with the coarsened terrigenous grain-size and reduced terrigenous fluxes (decreased Ti/Ca ratios), is mainly attributed to intense anthropogenic influences associated mainly with dam proliferation. Therefore, disturbed climate change information preserved in the terrigenous sediments can be linked to increased anthropogenic activities, perhaps representing an additional feature during the Anthropocene epoch.

The Effect of Ultrasonic Treatments on Current Transport Processes in Al‐Al2O3‐p‐CdTe‐Mo Structure

It was established that ultrasonic treatments (USTs) have practically no effect on the patterns of current flow in the Al‐Al2O3‐p‐CdTe‐Mo structure in the forward direction, namely, as in the absence of ultrasonic action, they appear in the sequence J∼V, J∼V2, J∼V5.3, and J∼V2. The effect of ultrasonic treatments affects only the magnitude of the flowing current; at low voltages, the current becomes somewhat larger, and at high voltages, it practically does not change. Changes in the magnitude of the flowing current are explained on the basis of the assumption that the recombination of nonequilibrium carriers in such a structure occurs through complex pair recombination complexes and, as a result of ultrasonic treatments, the number of both small acceptors and deep recombination centers increases.

Charge transport features of CdTe-based X- and [formula omitted]-ray detectors with Ti and TiO[formula omitted] Schottky contacts

The X- and γ-ray detectors, formed as Ti/p-CdTe/Au/Cu and TiOx/p-CdTe/MoOx diode structures with Ti and TiOx Schottky contacts, created by electron-beam evaporation and DC reactive magnetron sputtering of Ti, respectively, have been investigated. The structural, electrical and spectroscopic properties of the Schottky diodes were studied by X-ray diffraction, I–V characteristic and isotope spectrum measurements, respectively. The current transport processes in the Ti/p-CdTe/Au/Cu and TiOx/p-CdTe/MoOx heterostructures at relatively low voltages were well described by the models of the carrier generation–recombination in the space-charge region and space-charge limited current. Comparing the experimental data and calculation results, the energies of generation–recombination centers and hole traps, density of discrete trapping centers were determined, and charge carrier lifetimes. A rapid increase in the reverse current due to the Poole–Frenkel emission was observed and this was attributed to the presence of a thin intermediate insulator layer in the p-CdTe/MoOx interface (near-contact contact). The I–V characteristics of the Schottky diodes have been analyzed using the model of space-charge limited current taking into account the Poole–Frenkel effect. The TiOx/p-CdTe/MoOx detectors were tested using 241Am isotope emission.

Decrypting silicic magma/plug fragmentation at Azufral crater lake, Northern Andes: insights from fine to extremely fine ash morpho-chemistry

Azufral (SW Colombia) is a dangerous silicic volcano hosting a crater lake, which serves as an excellent example of an incipient plug disruption through phreatomagmatism. We studied the youngest succession of dilute pyroclastic density currents (PDCs) onlapping the north-eastern crater rim. Scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy was used to carry out an automated single-particle analysis of fine to extremely fine ash. We were able to obtain fast and accurate chemical analysis and imaging of 15,098 particles within the 250–63-μm and the 63–32-μm size ranges. The 2D form and roughness parameters were determined for 4895 juvenile glassy particles and validated by 3D micro-X ray computer tomography. There are two end members of high (group 1) and low (group 2) roughness juvenile glassy particles. Group 1 comprises high-roughness glass particles with solidity values as low as 0.34 in 2D and 0.33 in 3D, and convexity values as low as 0.33 in 2D and 0.26 in 3D. Group 2 comprises low-roughness glass particles with 2D solidity values > 0.79 and 3D solidity values typically > 0.58. In this group, 2D convexity values are > 0.68 and 3D convexity values are > 0.71. Both end members are mostly discriminated by the 2D Concavity Index (0.14 to 0.77 in group 1 vs. 0.05–0.35 in group 2). The remaining group 3 comprises particles of intermediate roughness values. In this study, we show how an incipient plug developed over a short repose time might be subjected to only a few cycles of vesicle nucleation, collapse and densification, retaining the characteristics of juvenile glass. Each glassy juvenile ash type, defined by a particular morphology, roughness and microtexture can be linked to a density “stratified” conduit model. In Azufral, the capping and conduit lining dense regions and the permeable zones of the incipient plug likely cracked. The newly formed cracks could allow hydraulic forcing caused by external water and induce phreatomagmatic interaction. This interaction favoured the fine fragmentation of the plug while enhancing ongoing magmatic processes. Finally, the variations of bulk componentry provided clues on dilute pyroclastic density current transport and physical fractionation processes by secondary fragmentation, elutriation and interaction with the crater rim.

Features of current transport in Al–Al2O3–p-CdTe–Mo structure

The results of studies of the current-voltage characteristics of the Al–Al2O3–p-CdTe–Mo structure in the forward direction of the current in the dark and under light illumination have been presented. These characteristics have four sections of the power-law dependence of the current on the voltage in the form J ~ Vα. It has been shown that the Al–Al2O3–p-CdTe–Mo structure can be considered as a n+-p diode structure with a long base, in which the current transport processes are described by the drift model of ohmic relaxation under conditions of non-equilibrium carriers recombination occurring through a pair two-level recombination complex.

Vertical current transport processes in MOS-HEMT heterostructures

The nature of vertical electron transport through MIS structures has not been fully understood until now. This applies all the more to metal/Al2O3/GaN/AlGaN/GaN heterostructures used in GaN-based MOS-HEMTs. Devices based on such heterostructures are utilized in power electronics applications and are frequently intended for use at very high temperatures. Regrettably, there are only few works dealing with the effect of heat on the current transport in such devices. Therefore, we describe a novel model for vertical electron transport through GaN-based MOS-HEMT structures, simulate the gate currents, and compare the results with experimental high-temperature I-V curves. In the present paper we show that trap-assisted tunnelling (TAT) between the metal and the surface of the semiconductor is the main transport mechanism in such MOS structures.

Burn-In Degradation Mechanism Identified for Small Molecular Acceptor-Based High-Efficiency Nonfullerene Organic Solar Cells.

Organic solar cells (OSCs) have again become a hot research topic in recent years. The record power conversion efficiency (PCE) of OSCs has boosted to over 17% in 2020. Apart from the high PCE, the stability of OSCs is also critical for their future applications and commercialization. Recently, many studies have proposed that burn-in degradation can be considered as an ineluctable barrier to long-term stable OSCs. However, there is still lack of studies to explain the detailed mechanism of this burn-in process. In this work, we first investigated the mechanism of the burn-in process in the high-efficiency PM6:N3-based nonfullerene OSCs. The PM6:N3-based device achieved a profound average PCE of 14.10% but also showed a significant performance loss after the burn-in degradation. Following characterizations such as dark J-V, photoluminescence (PL), time-resolved PL, Urbach energy estimation, and electrochemical impedance spectroscopy reveal that the burn-in degradation observed is closely related to the current extraction, energy transfer, nonradiative recombination, and charge transport process in the PM6:N3-based device. At the same time, it has small effects on the exciton dissociation process and energetic disorder in the PM6:N3-based device. Atomic force microscopy, scanning electron microscopy, transmission electron microscopy, and grazing incidence X-ray diffraction measurements gratifyingly found that the morphology of the PM6:N3 active layer is relatively stable during the burn-in degradation. Therefore, these observed degradations are suspected results from the instability of interfaces and electrodes. The atoms in carrier transport layers and electrodes may diffuse to the active layer during the degradation, which changes the energy levels of each layer and causes traps at the interface and in the active layer. Conquering the instability of interfaces and electrodes is proposed as the prior task for PM6:N3-based OSCs to achieve long-term stability. Our study provides insights into the mechanism behind the burn-in degradation of the PM6:N3-based OSCs, which takes the first step to conquer this barrier.

Productivity improvement of tower crane in tall buildings

The tower crane is an electromechanical equipment that is used for the vertical transport of materials in a construction project and together with the two riggers form the work team to carry out this task. One of the main problems in the construction of multifamily buildings corresponds to the use of the tower crane because vertical transport causes non-contributory times, which is, dead times and waits above expectations. This research analyzes the current vertical transport process and proposes its optimization through some management tools with the aim of improving the productivity of the use of the tower crane by reducing non-contributory times. To this end, the productivity of the work team is recorded in several projects with similar characteristics, then the main problems are selected to analyze them and finally the process is optimized. The results determined that non-contributory times can be reduced by 10% if there is an orderly and continuous process.

Assessment of River Morphological Change for Co Chien Estuary Applying the CCHE2D Model

Two-dimensional (2D) numerical models are useful tools for studying river morphology. Frequently, 2D numerical models are often applied to predict the impacts of the artificial changes to rivers and estuaries. These changes may be caused by altered watershed hydrology, variations in the sediment supply and the construction of artificial works such as dams, embankments and tidal gutters. The aim of this study was to apply the CCHE2D model in simulating riverbed morphological variation in the Co Chien Estuary of Vietnam with complex morphology under the combined impacts of hydrodynamic processes such as waves, flow field, tidal currents and sediment transport. First, the proposed model was calibrated using water surface level and current speed data during dry and flood seasons in 2010. Calibrated results showed satisfactory coefficients (root mean square error smaller than 0.10 and Brier skill score (BSS) criteria varying between 0.63 and 0.94). Second, the proposed model is applied to simulate riverbed level variation for Co Chien Estuary after the 6-year flood (2010–2015). The results were evaluated comparing deviations between simulated and measured elevations at multiple monitoring cross sections and longitudinal bed profiles after the 6-year flood. Compared results confirmed that the proposed model is suitable for simulating hydrodynamic processes and riverbed morphological changes in the study area with BSS criteria greater than 0.68. The proposed model is a useful tool to help efficiently manage resources and minimizing the unwanted influences of wave, current, tide and sediment transport process.

Evaluation of temperature dependent electrical transport parameters in Fe3O4/SiO2/n-Si metal–insulator-semiconductor (MIS) type Schottky barrier heterojunction in a wide temperature range

In this manuscript, we reported the electrical characteristics and structural analysis of In/Fe3O4/SiO2/n-Si/In MIS-type SBD heterostructure comprehensively in the temperature range 10–300 K using I–V, XRD, TEM and AFM measurements. Pulsed laser deposition in association with DC magnetron sputtering techniques has been utilized to fabricate the proposed In/Fe3O4/SiO2/n-Si/In heterojunction. The fabricated heterojunction revealed that the I–V curves are non-linear and asymmetric in nature. Using these I–V curves in the forward-bias region, SBH is calculated as 0.02 eV at 10 K and 0.74 eV at 300 K. On the other hand, the ideality factor (n) value was calculated as 7.55 at 10 K and 1.37 at 300 K. The series resistance (RS) values were also evaluated using Chenug’s method and the values were 1121 Ω at 10 K and 334 Ω at 300 K. The dependence of important diode parameters such as SBH, ‘n’ and ‘RS’ on measurement temperature was effectively explained firstly on account of triple Gaussian distribution of barrier heights with the help of barrier inhomogeneities of the prepared heterojunction. The value of the Richardson’s constant calculated for the fabricated In/Fe3O4/SiO2/n-Si/In heterojunction in the 110–300 K temperature regime was calculated to be 115.26 A/cm2K2 and is approximately equal to the theoretical value of 120 A/cm2K2 for n-type Si. In addition, the higher value (greater than one) of ideality factor at all operating temperatures from 10–300 K demonstrated that the probable current transport across the Fe3O4/SiO2/n-Si junction is not only due to the thermionic emission (TE) mechanism. Hence, to reveal the origin of current transport mechanism i.e., other than TE, we noticed that the governing current transport process through the fabricated hetrojunction is mainly due to the tunneling assisted Poole–Frenkel class of emission across the Fe3O4/SiO2/n-Si junction which is found to be temperature-dependent.

Observation of internal tides and sediment transport processes at the head of Logan Canyon on central Scotian Slope, eastern Canada

Abstract An instrumented seabed lander was deployed in the head of Logan Canyon in ~280 m water depth in 2005 to obtain the first observations of near-bed hydrodynamics and sediment transport processes in a shelf incising canyon on the glaciated Scotian Slope under strong influence of storms and ocean currents. The seafloor at the head of Logan Canyon is quite dynamic. Hourly mean current speeds can reach 35 cm/s while the maximum instantaneous currents are up to 70 cm/s. Under the forcing of semi-diurnal tides, the bottom currents are dominated by high frequency alternating up- and down-canyon current pulses of internal tides that cause periodic bedload and suspended load sediment transport. The current and sediment transport processes of the internal tides likely extend down to 800–1000 m depths along the canyon to contribute to the observed distribution of Holocene fine sand in the head and talweg of Logon Canyon. The high-frequency current and sediment concentration data show that the temporal changes of the current pulses are well correlated with the changes of temperature and sediment resuspension to demonstrate strong asymmetric patterns. The amplified currents of the internal tides cause the fine sands at the head of Logan Canyon to be transported as bedload in 2.1% of the time and in suspended-load in 1.2% of the time. Suspended-load transport is dominant over bedload transport. The maximum suspended sediment concentrations may reach ~100 mg/l in strong current events. As down-canyon transport is generally stronger and more frequent and the residual current is down-canyon, the net transport of sediment is in the down-canyon direction. Summer storms do not seem to directly impact the bottom currents at the head of Logan Canyon. However, sediments resuspended on the shelf during storms can be advected down slope into the canyon to cause events of substantially high sediment concentration enhancing sediment supply and transport at the head of Logan Canyon.

Improving the handover and transport of critically ill pediatric patients.

The aims of this project were to (a) determine barriers to current handover and transport process, (b) develop a new protocol and process for team-to-team handover, and (c) evaluate staff satisfaction with the new process. The handover and transport of critically ill patients from the paediatric emergency department to the paediatric intensive care unit is a period of vulnerability associated with adverse events. A mixed-methods study using a quasi-experimental design and qualitative approach. Focus groups were conducted to determine the barriers and facilitators of the current handover and transport process. Using these themes, a multidisciplinary team developed and implemented a new process including establishment of eight patient criteria for specialised transport and a standardised, interdisciplinary handover tool for team-to-team handover. Staff satisfaction was examined pre- and postintervention. Content analysis of focus groups revealed five categories: need for improved communication, cultural dissonance among units, defects in system and processes, need for standardisation and ambiguity between providers regarding acuity. Staff members reported improvements in their perceptions of satisfaction, safety, communication and role understanding associated with the new process. Standardisation through the establishment of severity of illness criteria and communication tools creates shared mental models and decreases risks to safety. A paradigm shift of team-to-team handover and transport is recommended. This paper suggests the importance of improving communication during the handover and transport process through establishing standardised patient severity of illness criteria, use of standardised tools and team-to-team handover processes.