Initial Tap Research Articles

Interpersonal synchrony enhanced through 20 Hz phase-coupled dual brain stimulation.

Synchronous movement is a key component of social behavior in several species including humans. Recent theories have suggested a link between interpersonal synchrony of brain oscillations and interpersonal movement synchrony. The present study investigated this link. Using transcranial alternating current stimulation (tACS) applied over the left motor cortex, we induced beta band (20 Hz) oscillations in pairs of individuals who both performed a finger-tapping task with the right hand. In-phase or anti-phase oscillations were delivered during a preparatory period prior to movement and while the tapping task was performed. In-phase 20 Hz stimulation enhanced interpersonal movement synchrony, compared with anti-phase or sham stimulation, particularly for the initial taps following the preparatory period. This was confirmed in an analysis comparing real vs pseudo pair surrogate data. No enhancement was observed for stimulation frequencies of 2 Hz (matching the target movement frequency) or 10 Hz (alpha band). Thus, phase-coupling of beta band neural oscillations across two individuals’ (resting) motor cortices supports the interpersonal alignment of sensorimotor processes that regulate rhythmic action initiation, thereby facilitating the establishment of synchronous movement. Phase-locked dual brain stimulation provides a promising method to study causal effects of interpersonal brain synchrony on social, sensorimotor and cognitive processes.

Fabrication and characterization of powder metallurgy tantalum components prepared by high compaction pressure technique

The present study has investigated the consolidation behaviors of tantalum powders during compaction and sintering, and the characteristics of sintered components. For die compaction, the densification behaviors of the powders are simulated by finite element analyses based on the yield function proposed by Shima and Oyane. Accordingly, the green density distribution for coarser particles is predicted to be more uniform because they exhibits higher initial relative tap density owing to lower interparticle friction. It is also found that cold isostatic pressing is capable of producing higher dense compacts compared to the die pressing. However, unlike the compaction behavior, the sintered density of smaller particles is found to be higher than those of coarser ones owing to their higher specific surface area. The maximum sintered density was found to be 0.96 of theoretical density where smaller particles were pressed isostatically at 400MPa followed by sintering at 2000°C. Moreover, the effects of processing conditions on grain size and texture were also investigated. The average grain size of the sintered specimen is 30.29μm and its texture is less than 2 times random intensity. Consequently, it is concluded that the higher pressure compaction technique is beneficial to produce high dense and texture-free tantalum components compared to hot pressing and spark plasma sintering.

Endophthalmitis following intravitreal injection of anti-VEGF agents: long-term outcomes and the identification of unusual micro-organisms.

BackgroundWhile the development of targeted molecular therapy to inhibit vascular endothelial growth factor (VEGF) has revolutionized the treatment and visual prognosis of highly prevalent retinal diseases such as diabetic retinopathy and age-related macular degeneration, each intravitreal injection of these agents carries a small risk of endophthalmitis which can be visually devastating. In the absence of specific guidelines, current management of post-injection endophthalmitis is typically extrapolated from data regarding endophthalmitis occurring after cataract surgery despite potential differences in pathogenic organisms and clinical course. Here, we assess the contribution of intravitreal injections of anti-VEGF agents to all cases of endophthalmitis at our tertiary care referral center and characterize the clinical outcomes and microbial pathogens associated with post-injection endophthalmitis in order to inform management of this serious iatrogenic condition.ResultsDuring the 7-year study period analyzed, 199 cases of endophthalmitis were identified using billing records. Of these, the most common etiology was post-surgical, accounting for 62 cases (31.2 %), with bleb-associated, endogenous, and corneal ulcer-related infections representing the next most frequent causes, comprising 15.6 % (31/199), 13.1 % (26/199), and 13.6 % (27/199) of all cases, respectively. Intravitreal injections of anti-VEGF agents represented 8.5 % of endophthalmitis (17/199 cases). Intraocular cultures yielded positive results in 75 % of post-injection cases, with the majority associated with coagulase-negative Staphylococcus. Consistent with prior literature, a case of Strep viridans displayed more rapid onset and progression. We also report the first association of Enterobacter cloacae and Lactococcus garvieae with post-injection endophthalmitis. While all but one patient were treated with initial vitreous tap and intravitreal injection of antibiotics, both patients with these rare organisms exhibited persistent vitritis requiring subsequent vitrectomy. Long-term outcomes of post-injection endophthalmitis indicated visual recovery to baseline levels, even with resumption of anti-VEGF agents following resolution of the acute infection.ConclusionsAcute endophthalmitis following intravitreal injections of anti-VEGF agents is an uncommon but potentially devastating complication which may be managed effectively with vitreous tap and injection of intravitreal antibiotics. However, persistent vitritis requiring subsequent vitrectomy should raise suspicion for unusual pathogens.

What is the risk of infecting a cerebrospinal fluid-diverting shunt with percutaneous tapping?

Most CSF-diverting shunt systems have an access port that can be percutaneously tapped. Tapping the shunt can yield valuable information as to its function and whether an infection is present. The fear of causing a shunt infection by tapping may limit the physician's willingness to do so. The authors of this study investigate the risk of infecting a shunt secondary to percutaneous tapping. Following institutional review board approval, CSF specimens obtained from tapping an indwelling CSF-diverting shunt during the 2011 and 2012 calendar years were identified and matched with clinical information. A culture-positive CSF sample was defined as an infection. If results were equivocal, such as a broth-only-positive culture, a repeat CSF specimen was examined. The CSF was obtained by tapping the shunt access port with a 25-gauge butterfly needle after prepping the unshaven skin with chlorhexidine. During the study period, 266 children underwent 542 shunt taps. With 541 taps, no clinical evidence of a subsequent shunt infection was found. One child's CSF went from sterile to infected 11 days later; however, this patient had redness along the shunt tract at the time of the initial sterile tap. The risk of infection from tapping a shunt is remote if the procedure is done correctly.

Onset of an Outbreak of Bipolaris hawaiiensis Fungal Endophthalmitis after Intravitreal Injections of Triamcinolone

To report a series of cases with fungal endophthalmitis occurring after intravitreal injection of triamcinolone derived from a single lot prepared by a compounding pharmacy. Retrospective, observational case series. Seventeen eyes treated with triamcinolone obtained from a single lot subsequently found to be contaminated with Bipolaris hawaiiensis. A retrospective chart review in a single retina practice was performed for 15 patients (n= 17 eyes) who received intravitreal injections of triamcinolone obtained from a single compounding pharmacy. Medical records and cytologic and microbiologic results were reviewed from December 2011 through January2013. Visual acuity; presence of vitreous cell, anterior chamber cell, or both; and fungal detection in samples obtained by vitreous needle aspiration or vitreous biopsy. Fungal endophthalmitis developed in 82% (14/17) of eyes after intravitreal triamcinolone obtained from the same lot. Median onset was 83 days (range, 6-322 days). Preinjection visual acuity ranged from 20/20 to counting fingers (median, 20/50). Median visual acuity at last follow-up was 20/400 (range, 20/30-no light perception). The most common signs and symptoms included decreased vision (57% [8/14]), vitreous cell (64% [9/14]), and anterior chamber cell (50% [7/14]). Fungus was detected by cytologic or culture examination in 7% (1/14) from initial vitreous tap. By comparison, vitreous samples obtained by pars plana vitrectomy (PPV) resulted in fungus-positive cytologic results in 43% (6/14) of eyes and positive culture results in 36% (5/14) of eyes. All culture-positive specimens (100% [5/5]) were identified as B.hawaiiensis. Overall, fungal infection was confirmed in 57% (8/14) of eyes by either cytologic or microbiologic analysis. Fungal endophthalmitis resulting from B.hawaiiensis developed in a series of eyes after intravitreal injections of triamcinolone obtained from a single compounding pharmacy. Clinical presentation of infection can be delayed up to 10 months. Vitreous tap may be inadequate, and direct vitreous biopsy by PPV may be preferred to identify fungal endophthalmitis and facilitate prompt diagnosis and treatment.

Micro/nano-complex-structure SiOx–PANI–Ag composites with homogeneously-embedded Si nanocrystals and nanopores as high-performance anodes for lithium ion batteries

The extremely large volume variation and poor electronic conductivity of Si anode materials for lithium ion batteries have seriously hampered their performances and practical applications. SiOx materials are regarded as ideal alternatives to high-capacity Si anode materials for Li-ion batteries, since the generated Li2O matrix from Li–SiOx reactions can effectively accommodate the large volume swing of Si. Furthermore, micron-sized particles with much smaller surface area always present higher initial coulombic efficiency and tap density than nanomaterials. Based on the above considerations, SiOx microparticles with homogeneously-embedded Si nanocrystals and nanopores were fabricated by magnesiothermic reduction in this work and were further modified by high-electronic-conductivity and flexible polyaniline (PANI)–Ag shell. Profiting from these favorable features, the obtained SiOx–PANI–Ag micron-composites exhibited better cycling performances (with a reversible capacity of 1149 mA h g−1 after 100 cycles), good initial coulombic efficiency and tap density in comparison with SiOx-based materials in other works. This study promotes us to exploit advanced Si- or Sn-based materials for Li ion batteries and preparing micro/nano complex structures for promising applications.

Li‐ion Reaction to Improve the Rate Performance of Nanoporous Anatase TiO2 Anodes

AbstractLarge initial capacity losses and low tap densities are among the major challenges to the wide‐ranging application of Li ion batteries based on anatase titania (TiO2) anodes. This study reports the root causes of the capacity losses and proposes effective ways to control them. Nanoporous TiO2 microspheres with a tap density as high as 1.1 g cm−3 are successfully prepared by using a spray drying method and a focused study is made of their electrochemical reaction kinetics. According to the results, the capacity losses are ascribed to the irreversible Li‐ion interfacial storage capability that arises mainly from the high reactivity between TiO2 and the electrolyte solution. A new anode material, TiO2–Li, prepared by reacting TiO2 with Li ions delivers a 50 % reduction in charge‐transfer resistance and a remarkable enhancement of Li‐ion diffusion coefficient by almost seven times, as compared to the neat TiO2 powders. The TiO2–Li anode presents a much lower initial capacity loss, higher rate performance, and better reversibility.

Modified Constant Modulus Algorithm With Polarization Demultiplexing in Stokes Space in Optical Coherent Receiver

We propose a modified method of constant modulus algorithm (CMA) based on polarization demultiplexing in Stokes space for polarization demultiplexing (SS-PDM) in optical coherent receivers. SS-PDM can tolerate chromatic dispersion (CD) and polarization-dependent loss (PDL), but is sensitive to PMD. On the other hand, the CMA with high-order FIR filters could compensate for polarization-mode-dispersion (PMD) effectively, but suffers from the singularity problem which results from PDL. Therefore, we use the polarization rotation matrix estimated by SS-PDM to set the initial center taps of the CMA. The singularity problem of the CMA is avoided effectively in a much wider range of PDL and its convergence speed is also improved. We demonstrate this modified CMA in a simulation of 100-Gbit/s PDM-QPSK with PDL of 1, 3, and 5 dB, respectively. PDL is emulated by attenuating one polarization tributary before polarization multiplexing and the interaction between PDL and PMD is ignored. The singularity problem disappears as expected. Because the tolerance of PDL is affected by DGD, we further investigate the PDL tolerance under different DGD. Finally, we conduct the simulation of 100-Gbit/s PDM-QPSK with PDL of 3 dB over 3000 km SSMF and 4000 km SSMF separately. The convergence speed accelerates indeed compared with that of the conventional CMA.

Streptococcus Endophthalmitis Outbreak after Intravitreal Injection of Bevacizumab: One-Year Outcomes and Investigative Results

To report the 1-year clinical outcomes of an outbreak of Streptococcus endophthalmitis after intravitreal injection of bevacizumab, including visual acuity outcomes, microbiological testing, and compound pharmacy investigations by the Food and Drug Administration (FDA). Retrospective consecutive case series. Twelve eyes of 12 patients who developed endophthalmitis after receiving intravitreal bevacizumab prepared by a single compounding pharmacy. Medical records of patients were reviewed; phenotypic and DNA analyses were performed on microbes cultured from patients and from unused syringes. An inspection report by the FDA based on site visits to the pharmacy that prepared the bevacizumab syringes was summarized. Visual acuity, interventions received, time to intervention, microbiological consistency, and FDA inspection findings. Between July 5 and 8, 2011, 12 patients developed endophthalmitis after intravitreal bevacizumab from syringes prepared by a single compounding pharmacy. All patients received initial vitreous tap and injection, and 8 patients (67%) subsequently underwent pars plana vitrectomy (PPV). After 12 months follow-up, outcomes have been poor. Seven patients (58%) required evisceration or enucleation, and only 1 patient regained pre-injection visual acuity. Molecular testing using real-time polymerase chain reaction, partial sequencing of the groEL gene, and multilocus sequencing of 7 housekeeping genes confirmed the presence of a common strain of Streptococcus mitis/oralis in vitreous specimens and 7 unused syringes prepared by the compounding pharmacy at the same time. An FDA investigation of the compounding pharmacy noted deviations from standard sterile technique, inconsistent documentation, and inadequate testing of equipment required for safe preparation of medications. In this outbreak of endophthalmitis, outcomes have been generally poor, and PPV did not improve visual results at 1-year follow-up. Molecular testing confirmed a common strain of S. mitis/oralis. Contamination seems to have occurred at the compounding pharmacy, where numerous problems in sterile technique were noted by public health investigators.

The results of pars plana vitrectomy and silicone oil tamponade for endophthalmitis after intravitreal injections

To report the role of early vitrectomy and silicone oil tamponade in acute endophthalmitis following intravitreal injection. Medical records of eight patients who presented with acute endophthalmitis after intravitreal injection of different drugs were retrospectively reviewed. Initial treatment consisted of vitreous tap with cultures and injection of intravitreal antibiotics, with the patients subsequently undergoing pars plana vitrectomy and silicone oil tamponade within 24h following initial vitreous tap. The mean time to presentation was 1.7days (1-3days). The initial best-corrected visual acuity was hand motion to 0.05 before treatment and 0.05-0.8 (Snellen) after treatment. Vitreous cultures were obtained from all patients, of which four were culture positive. Endophthalmitis was controlled in all patients. There was no retinal detachment or phthisis bulbi during the follow-up period (1-4years). Acute endophthalmitis following intravitreal injection occurs rapidly and requires urgent treatment. If intravitreal antibiotics fail to control inflammation, early pars plana vitrectomy and silicone oil tamponade would be an appropriate option.

Ultrafast and low overhead training symbol based channel estimation in coherent M-QAM single-carrier transmission systems

We propose a training symbol based channel estimation (TS-EST) algorithm that estimates the 2 × 2 Jones channel matrix. The estimated matrix entries are then used as the initial center taps of the 2 × 2 butterfly equalizer. Employing very few training symbols for TS-EST, ultrafast polarization tracking is achieved and tap update can be initially pursued using the decision-directed least mean squares (DD-LMS) algorithm to mitigate residual intersymbol interference (ISI). We experimentally verify the proposed TS-EST algorithm for 112 Gbps PDM-QPSK and 224 Gbps PDM-16QAM systems using 10 and 40 training symbols for TS-EST, respectively. Steady-state and transient bit error rates (BERs) achieved using the TS-EST algorithm are compared to those obtained using the constant modulus algorithm (CMA) and the training symbol least mean squares (TS-LMS) algorithm and results show that the proposed TS-EST algorithm provides the same steady-state BER with a superior convergence speed. Also, the tolerance of the proposed TS-EST algorithm to laser phase noise and fiber nonlinearity is experimentally verified. Finally, we show by simulation that the superior tracking speed of the TS-EST algorithm allows not only for initial polarization tracking but also for tracking fast polarization transients if four training symbols are periodically sent during steady-state operation with an overhead as low as 0.57%.

Developmental lead exposure causes startle response deficits in zebrafish

Lead (Pb 2+) exposure continues to be an important concern for fish populations. Research is required to assess the long-term behavioral effects of low-level concentrations of Pb 2+ and the physiological mechanisms that control those behaviors. Newly fertilized zebrafish embryos (<2 h post fertilization; hpf) were exposed to one of three concentrations of lead (as PbCl 2): 0, 10, or 30 nM until 24 hpf. (1) Response to a mechanosensory stimulus: Individual larvae (168 hpf) were tested for response to a directional, mechanical stimulus. The tap frequency was adjusted to either 1 or 4 taps/s. Startle response was recorded at 1000 fps. Larvae responded in a concentration-dependent pattern for latency to reaction, maximum turn velocity, time to reach V max and escape time. With increasing exposure concentrations, a larger number of larvae failed to respond to even the initial tap and, for those that did respond, ceased responding earlier than control larvae. These differences were more pronounced at a frequency of 4 taps/s. (2) Response to a visual stimulus: Fish, exposed as embryos (2–24 hpf) to Pb 2+ (0–10 μM) were tested as adults under low light conditions (∼60 μW/m 2) for visual responses to a rotating black bar. Visual responses were significantly degraded at Pb 2+ concentrations of 30 nM. These data suggest that zebrafish are viable models for short- and long-term sensorimotor deficits induced by acute, low-level developmental Pb 2+ exposures.

Major and trace elements in tap water from Italy

Tap water is a fundamental resource for everyday life, it is subjected to several routine controls and needs to fulfill many compliance scheme. Several elements are monitored on a regular basis, but many trace chemical elements are not usually analyzed, so there is the need to have some kind of indication about their concentration and variation ranges in order to better assess the water quality. An opportunity for such investigations has been provided by a project of the EuroGeoSurvey Geochemistry Expert Group aimed at the characterization of groundwater geochemistry using bottled mineral waters purchased in supermarkets all over Europe which included also the analysis for comparative purpose, of tap water. The initial tap water database of 24 sites has been subsequently increased to the final number of 157 distributed all over Italy and representative of end-user situations (either private houses and public places). In the samples, pH, conductivity and concentrations of 69 elements (Ag, Al, As, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, I, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Pb, Pr, Rb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb, Zn, Zr, Br −, HCO 3 −, Cl −, F −, NH 4 +, NO 2 −, NO 3 −, PO 4 3−, SO 4 2−,SiO 2) were measured at the BGR geochemical laboratories. Some major elements (Ca, HCO 3 −, Mg), the dominant water type, display limited range of variation whereas for others (Na, Cl −) the scattering is wider (3 orders of magnitude). Only one sample for Cl and two samples for NO 3 − are above the recommended EU and Italian guidelines. Clear influence of bedrock geology and/aquifer composition is clear for some elements (e.g. As, F, Rb, V, U), other elements are indicator of mixing with deep formation water or sea-spray contribution (e.g. Br, I), others reflect also peculiar geographic area (e.g. B in Tuscany, Se in Emilia-Romagna). Factor analysis enabled the identification of a “corrosion” factor which includes Pb, Zn, Cd, Cu, Mn, Sn and Fe, all elements which are preferentially related to interaction with the distributing system pipelines.

ENDOGENOUS METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS ENDOPHTHALMITIS

To report on the presentation, treatment, and outcomes of the largest series to date for patients with endogenous methicillin-resistant Staphylococcus aureus endophthalmitis at a single institution and compare the results from previously published reports of this disease entity. Retrospective, noncomparative, consecutive case series of patients who were treated for endogenous methicillin-resistant S. aureus endophthalmitis from a single tertiary referral institution were reviewed. Eight eyes of seven consecutive patients, with a mean age of 58.1 years, were diagnosed with culture-proven endogenous methicillin-resistant S. aureus endophthalmitis. Five patients were male, and six patients had a unilateral presentation. Five of eight eyes were treated with initial vitreous tap and injection of antibiotics, and six eyes showed a retinal detachment during the course of treatment. Final visual acuity ranged from 20/40 to no light perception, and 5 of 8 eyes showed improvement in visual acuity from initial presentation. Only one eye became blind and painful and required enucleation. This series represents the largest single-institution report on endogenous methicillin-resistant S. aureus endophthalmitis and associated outcomes. Although previously reported cases cited poor visual outcomes and high enucleation rates, the authors' current series shows that retinal detachments are common and enucleation rates are low.

Culture-positive endophthalmitis 6 hours after intravitreal antibiotics.

The purpose of this study was to report culture-positive endophthalmitis after intravitreal antibiotic injection and initial culture-negative tap. This is an interventional case report of an 84-year-old woman who underwent vitrectomy and intravitreal antibiotic injection. The main outcome measures include resolution of infection, inflammation, and visual acuity improvement. Endophthalmitis after intravitreal pegaptanib injection was treated initially with a vitreous and aqueous tap and intravitreal antibiotic injection at a satellite clinic, because the patient was seen 5 hours from the nearest retina surgical facility. She subsequently underwent vitrectomy and intravitreal antibiotic injection. The initial culture results were negative and only the second culture was positive for Staphylococcus aureus. One year later, visual acuity was 20/30 after cataract extraction with intraocular lens implantation. When a suspected endophthalmitis case is seen many hours from a retina surgical facility, it may be best to perform tap and injection of intravitreal antibiotics although vitrectomy surgery may still be required but will be delayed.

IgG-index predicts neurological morbidity in patients with infectious central nervous system diseases

BackgroundPrognosis assessment of patients with infectious and neoplastic disorders of the central nervous system (CNS) may still pose a challenge. In this retrospective cross-sectional study the prognostic value of basic cerebrospinal fluid (CSF) parameters in patients with bacterial meningitis, viral meningoencephalitis and leptomeningeal metastases were evaluated.MethodsWhite blood cell count, CSF/serum glucose ratio, protein, CSF/serum albumin quotient and Immunoglobulin indices for IgG, IgA and IgM were analyzed in 90 patients with bacterial meningitis, 117 patients with viral meningoencephalitis and 36 patients with leptomeningeal metastases in a total of 480 CSF samples.ResultsIn the initial spinal tap, the IgG-index was the only independent predictor for unfavorable outcome (GOS < 5) in patients with infectious CNS diseases but not in patients with leptomeningeal metastases. The sensitivity and specificity of an IgG-index of 0.75 and higher for predicting unfavorable outcome was 40.9% and 80.8% in bacterial meningitis and 40% and 94.8% in viral meningoencephalitis, respectively. No significant associations between CSF parameters and outcome could be observed in follow-up CSF samples.ConclusionThe present study suggests that in infectious CNS diseases an elevated IgG-Index might be an additional marker for the early identification of patients at risk for neurological morbidity.

An improvement on constant modulus algorithm for polarization demultiplexing in optical coherent receivers

In order to solve the problem of ill-convergence for constant modulus algorithm (CMA) in polarization division multiplexing system with optical coherent receivers, a modified CMA based on bit error rate (BER) aiding to control initial tap setup, named as BER-Aiding CMA (BA-CMA), is proposed in this paper. By analyzing the principle of CMA for adaptive digital equalization and polarization demultiplexing, the convergence behavior that leads to undesirable result is evaluated and therefore BA-CMA is proposed. Simulation results show that the proposed algorithm is able to overcome the undesirable convergence effectively and keep inherent advantages of CMA at the same time.

Methicillin-resistant Staphylococcus epidermidis isolation from the vitrectomy specimen four hours after initial treatment with vancomycin and ceftazidime

A patient presented with acute-onset, postoperative endophthalmitis and visual acuity of light perception. Because of a time delay in arranging a pars plana vitrectomy (PPV), the patient was treated with a prompt vitreous tap for culture an injection of vancomycin and ceftazidime. Four hours later, the PPV was performed and additional antibiotics were injected. The cultures from both the initial needle tap and the subsequent PPV isolated methicillin-resistant Staphylococcus epidermidis sensitive to vancomycin, but resistant to fourth-generation fluoroquinolones. The patient eventually recovered a visual acuity of 20/80 before developing retinal detachment. This case illustrates the time lag necessary to sterilize the vitreous cavity, and suggests a possible two-step staged treatment strategy for situations in which access to PPV equipment and support staff may be limited.

Re-cycling of remediated soil – Evaluation of leaching tests as tools for characterization

In Sweden, leaching tests with deionized water (D.W.) are utilized in risk assessment of materials entering landfills, but implementation of these results to evaluate the risk of spreading of pollutants in the environment is difficult. One problem is that most leaching procedures only consider heavy metals release, whereas organic pollutants are left out. The aim of the present study was to assess the possible pollutant mitigation in four remediated soils, three with heavy metals and one with polycyclic aromatic hydrocarbons (PAH) contamination. The mitigation was evaluated by standardized batch and column leaching tests utilizing three different leaching solutions: D.W., a weak ionic solution (0.001 M CaCl 2) and an artificially made soil water (ASW). In general, batch leaching tests implied larger contaminant removal than column leaching test, possibly due to the more rough treatment of the soil particles, and guidelines would at times be exceeded by the batch leaching test but not by column leaching tests. Utilization of CaCl 2 was found to release less heavy metal than D.W., whereas the metals mobilized by ASW were removed from solution by the filtration of soil leachates. Low molecular weight PAH was most efficiently mobilized by CaCl 2, while D.W. worked better for high molecular weight PAH. Despite very low initial PAH-concentrations, tap- and groundwater criteria were exceeded by all leaching solutions.

Numerical Study on Metal/Slag Drainage Rate Deviation during Blast Furnace Tapping

Remarkable deviation of metal fraction in the liquid drained out of blast furnace tap hole has been occasionally observed between the operated tap holes and/or tapping time stages. Introducing the concept of low permeability zone whose wall, due to the difference in two liquid phases' viscosity and/or wettabilitiy to coke particle, allows for metal to permeate freely but for slag not to permeate, the liquid drainage behaviors are examined by furnace hearth mathematical model simulations.The deviation of metal fraction between two operated tap holes is materialized under the hypothesis that furnace heath is divided into two sections by planar vertical low permeability wall (VLPW). While, the variation of time series change in liquid metal fraction during tapping operation is reproduced by hypothesizing the formation of cylindrical low permeability wall (CLPW) which concentrically parts the furnace hearth into center and peripheral area.Since the results of calculation for VLPW or CLPW formation indicate the notable raise of liquid level in furnace which could influence on abrupt increase of blowing pressure, the effectiveness of several operational optimization is assessed, resulting in suggestive conclusion that increasing the initial tap hole diameter is the most effective.