Big Hole Research Articles

Trivial Muldoon

ALONG WITH RECHERCHÉ RHYMES, recondite forms, and repurposed clichés, the poetry of Paul Muldoon is full of trivia. Words most readers would not know, place names in Ireland and in New Jersey, facts and more facts, and sometimes a flurry of brand names: L. L. Bean, Coutts and Co., ‘Crested Ten on the rocks’.1 ‘Hartebeest bugle’. ‘Wright’s coal tar’.2 Randall Jarrell quipped that W. H. Auden’s learning made critics exclaim ‘what a queer thing for a poet to know!’, whereas the learning in Eliot and Pound made critics explain, instead, ‘What a queer thing for anybody to know!’3 Muldoon’s work – especially the late work, the work completed after his move to America – could provoke, and has provoked, both responses. Early Muldoon, written mostly in England and Ireland, was often noted for its lacunae, its modes of omission or stopping teasingly short; these omissions provoked deconstructionist readings, psychological interest in what he could not say, what culture will not let us say, and also complaints, most famously from Helen Vendler, who found ‘a big hole in the middle where the feeling should be’.4 The claim was unfair and yet accurate, in a way, since so many of the poems were about feeling alienated, not feeling what other people expect you to feel. (Almost literally so in the case of that marvellous, underrated, angry sonnet ‘The Ox’.)

Environmental Impact Assessment Due to Gas Seepage of Titas Gas Field, Bangladesh

The biggest gas field of Bangladesh, Titas in Brahmanbaria continues to face a possible disaster due to the seepage of the huge amount of gas mixed with water and oil through thousands of holes and cracks on the surface environment in and around this gas field. Gas is leaking through more than 3,000 big holes, including some 30-ft diameter ones, spreading in paddy fields, water bodies, and the Titas river. Approximately 1000 acres of virgin land with varieties of flora and fauna have been affected through seepage. Soil condition in the villages has degraded and still degrading to such an extent that it becomes unpredictable to comment on how many years it needs to regain fertility. Yet the present alarming situation is rippled with confusion about the actual source of seepage till now. To help the situation, an assessment of the impact of gas seepage from the Titas gas field on the surrounding environment was needed to evaluate the overall environmental condition at present and to propose adequate control measures for the abatement of the adverse impact on the environment. Therefore, the main objective of this research work is to assess the environmental impact of this seepage from the Titas Gas field. To fulfill the object of this study, we have developed a questionnaire including 18 parameters. These parameters encompassed all the aspects of ecology, socio-economic and so on. We visited the study area and made the gathering with affected peoples. The answer to each parameter of the questionnaire has been taken from people. From this study, it is found that all the tube wells of the villages are automatically emitting a huge quantity of natural gas. It is observed that the emitting of gas from the tube well-produced enormous irritating noise. The air is found polluted in and around the site visited. The most severe and alarming finding the health-related disease (skin disease, asthma, hair fall, water-born diseases e.t.c). It is summarized that about six square km of the area of Bakail, Suhilpur, Shampur and Anandapur villages, the Titas River and Loiska swamp are at high risk due the seepage.

Such Violent Laughter

Such Violent Laughter Alan Singer (bio) I sit and look at myself all day and cry. I have a big hole in the middle of my face that scares people, even myself, so I can't blame the boys for not wanting to take me out. … What did I do to deserve such a terrible bad fate? Even if I did do some bad things I didn't do any before I was a year old and I was born this way. I asked Papa and he says he doesn't know, but that maybe I did something in the other world before I was born or that maybe I was being punished for his sins. I don't believe that because he is a very nice man. Ought I commit suicide? —Nathanael West (1975, 4) "What did I do to deserve such a terrible fate?" "Ought I commit suicide?" The questions are serious, and as we sometimes say, seriously funny. Harold Bloom's appreciation of the passage quoted above from Nathanael West's remarkable novel Miss Lonelyhearts, takes account of our relief that the violence suffered by the questioner is hers to endure. By the same token, Bloom does not flinch from the recognition that West's narrative conscientiousness wrings a confession from his readers, that the laughter is ours. How do we laugh at such existential violence without fearing for our lives? How else can we live? The peculiar discomfort Bloom registers in his reflection on West's greatness as a novelist turns out to be the aim of more than one twentieth century American fiction writer. One only has to quickly thumb through Bloom's writings in his posthumous collection The American Canon to pick out a conspicuous bloody thread. The essays on Nathanael West, Flannery O'Connor, and William Faulkner configure themselves as a suite of reflections on what Bloom might argue is a uniquely American rapport with comic violence, though he doesn't deploy the term. One quickly understands that Bloom's enthusiasm for these authors individually and as a group derives from their syncretistic penchants for extorting laughter from our otherwise shocked witness to the most violent human actions. It is no coincidence that each of these authors is frequently mentioned in Bloom's appreciation of each of the others. More to the point, Gnosticism, a career long obsession of Bloom's, appears to be at the root of his experience reading of West, O'Connor, and Faulkner. From a Bloomian perspective, Gnosticism is arguably equivalent [End Page 479] to knowledge of our propensity for error and suffering. I would argue that it is oddly akin to Greek hamartia, the promise of corrigibility through experience. Bloom's readerly persistence through the trials of gnostic knowing is, thanks to Gershom Scholem's reliably paradoxical phrase, "redemption though sin, easily construed as acceptance of our entrapment in experience. The relevant sin here is especially cautionary for American readers who keep faith with the phantom of an American Adam. Sin is perforce the manner of human striving after more and more experience. What is redeemed is simply what is wrought through striving. Sin, after all is the refusal of death and transcendence. It is more durable. More to the point, it is do-able; it is brutal agency itself, unencumbered by the visionary spirits of romantic sublimity. In Bloom's opening essay on Emerson, the point is already taken: "Emerson is an experiential critic and essayist, and not a Transcendental philosopher" (Bloom 2019, 13). Bloom invites us to think of Emerson's American exemplarity (though he finds the same wisdom in the Bible, Shakespeare, Freud), as his acceptance of the confliction of experience. For Emerson "…we need to be everything in ourselves while we go on fearing that we are nothing in ourselves" (14). The literary imagination is quintessentially conflicted in the very impetus of the writer to imagine what is not the case. Of course the literary confliction that we know most terrifyingly, which is to say most violently, comes to us in the genre of tragedy where human agency hangs drastically in the balance. Oedipus is of course presumed to be mistaken about who he...

The Economics of Reorganizing Otolaryngology Out-Patient Services for COVID-19 Pandemic in Low- and Middle-Income Countries

The Coronavirus 2019 (COVID-19) pandemic has widespread implications for clinical practice of otolaryngologists in clinics and hospitals. With various reports of otolaryngology practitioners catching infection, a profound structural reorganization of ENT services in the clinic is mandatory for protecting both patients and healthcare workers. The present study focused on quantifying the cost involved in reorganizing the otolaryngology out-patient services in a third world country during the ongoing Covid-19 pandemic. Though the pandemic has increased the cost of running of an otolaryngology practice world over, the impact is huge in India as penetration of health insurance/social security is minimal. As out of pocket expenditure forms a significant proportion of healthcare spending by majority in India, any transfer of additional cost incurred because of Covid-19 pandemic to the patient will burn a bigger hole in their pocket.

Effects of Al2O3 coating induced structural and mechanical changes of C/C composites

Different C/C composites, identified as Cf/C, CAl2O3/C, C1600/C and C1600-Al2O3/C, were fabricated by condensation of different treated 3D needle-punched carbon fiber preforms through a thermal gradient chemical vapor infiltration (TG-CVI) method. Effects of high temperature treatment and Al2O3 coating of the carbon fiber preforms on matrix texture and mechanical properties of C/C composites were investigated. SL PyC is obtained for Cf/C and C1600/C, which preforms are without Al2O3 coating. Whereas the texture of carbon matrix for CAl2O3/C, and C1600-Al2O3/C changes to RL under the same deposition conditions, indicating that Al2O3 coating layer significantly affects the texture of carbon matrix. Heat treatment of the carbon fiber preforms at 1600 °C for 4 h obviously increase the toughness of the C/C composites. The fracture toughness increased by 226% from 0.938 MPa/m2 for Cf/C to 3.061 MPa/m2 for C1600-Al2O3/C. The significant toughness increasing is attributed to the unique fracture mode for C1600-Al2O3/C, where a hollow “cylindrical” PyC matrix is pulled out and a corresponding big hole is left with a central fiber in it. The flexural strength, however, is mainly affected by the final density of the C/C composites.

Enhancement of gas drainage efficiency in a special thick coal seam through hydraulic flushing

Coal seam gas is a kind of precious energy, but it also will be a terrible disaster in coal mining if not well controlled. Underground coal seam gas drainage is one of the most effective methods for lowering the risk of gas disaster. However, it is difficult to extract gas in many coal seams with low permeability, especially in tectonic coal seams, which were severely crushed or even pulverized by tectonism. The key to improving the gas drainage efficiency is stress relief and permeability increase. There are many conventional technologies to improve the gas drainage efficiency of a single coal seam, but they are inoperative on the special thick coal seam with a soft mylonitic tectonic coal sub-layer at the lower part. In this paper, to enhance gas drainage in this coal seam, we presented a hydraulic flushing gas drainage technology. Numerical simulation was conducted to analyze the stress evolution, plastic damage, permeability changes and gas drainage of the coal after hydraulic flushing. Further, abundant field experiments were carried out to investigate and verify the mechanism of stress relief and permeability increase. The results show that, after adopting the hydraulic flushing gas drainage technology, more tectonic coal in the thick coal seam was flushed out and the big hole in the tectonic coal sub-layer enlarged the range of stress relief and permeability increase, and the gas drainage efficiency increased significantly.

103.37 A sudoku puzzle with a big rectangular hole

103.37 A sudoku puzzle with a big rectangular hole

Dam Site Identification Using Remote Sensing and GIS (A case study Diamer Basha Dam Site)

Selection of suitable sites for construction of dam is the most important phase because a number of factors are required to consider that include topography, geology, tectonic settlements and the slope. We selected Diamer Basha dam site to analyze it feasibility considering real-time field data. Geologically the study site is a part of Chilas Mafic Igneous Complex which is not ophiolite. Matic complex is a block which is 40km in depth and 300km in length. These rocks are comparatively hard in nature and are considered good for construction of dam. Tectonically, we observed that the area under investigation was highly active tectonically. Surface deformation rates of the study site are highest throughout the world because this area is comprised of multiple fault lines that include Main Mantle Thurst (MMT), Main Karakoram Thrurst (MKT), Main Boundary Thurst (MBT) and many others. This area has become a hot cake for the geologist worldwide due to it’s very high surface deformation rates.Tectonically active regions are considered worst for construction sites, e.g., for dam sites. The dam site is actcually laying on the MKT which is not favorable for construction of Diamir Basha dam. A low-level earthquake may generate small cracks in concrete structure and any leakage of water may produce big holes with passage of time which are not remidable. A big level earthquake may vanish the dam site completely. Therefore, the current site is not favorable for construction of dam. 1, 2,3, 4, Muhammad Usman Tanveer1, Azeem Akhtar1, Azam Sohail1, Kashif Naeem1 and Syed Amer Mahmood1. 1 Department of Space Science, University of the Punjab Lahore, Punjab Pakistan. 2 University of the Central Punjab Lahore. 3 Punjab University, College of Information and Technology. 4 Punjab University, Centre for Geographic Information System.

Dam Site Identification Using Remote Sensing and GIS (A case study Diamer Basha Dam Site)

Selection of suitable sites for construction of dam is the most important phase because a number of factors are required to consider that include topography, geology, tectonic settlements and the slope. We selected Diamer Basha dam site to analyze it feasibility considering real-time field data. Geologically the study site is a part of Chilas Mafic Igneous Complex which is not ophiolite. Matic complex is a block which is 40km in depth and 300km in length. These rocks are comparatively hard in nature and are considered good for construction of dam. Tectonically, we observed that the area under investigation was highly active tectonically. Surface deformation rates of the study site are highest throughout the world because this area is comprised of multiple fault lines that include Main Mantle Thurst (MMT), Main Karakoram Thrurst (MKT), Main Boundary Thurst (MBT) and many others. This area has become a hot cake for the geologist worldwide due to it’s very high surface deformation rates.Tectonically active regions are considered worst for construction sites, e.g., for dam sites. The dam site is actcually laying on the MKT which is not favorable for construction of Diamir Basha dam. A low-level earthquake may generate small cracks in concrete structure and any leakage of water may produce big holes with passage of time which are not remidable. A big level earthquake may vanish the dam site completely. Therefore, the current site is not favorable for construction of dam.

Introduction

Uncertainty has been a pretty hot topic among academics and economists working in policy circles since the global financial crisis. I believe we now know a lot more about its effects on the business cycles of a variety of countries than we knew before the crisis. Uncertainty tends to be recessionary, it exerts stronger effects when the economy is already experiencing difficulties from an aggregate standpoint, or when financial markets operate less smoothly, and it tends to harm macroeconomic policies’ effectiveness. In spite of the impressive amount of knowledge accumulated so far, gaps in the literature are still present. First, we do not know much about how long term rates respond to uncertainty shocks. While dynamic stochastic general equilibrium models approximated at third order offer predictions on how the term structure responds to uncertainty shocks, the literature has not yet produced many model‐free reduced‐form types of regressions on the link between uncertainty and long rates. This is a big hole, given the relevance of long rates on consumption and investment decisions. Second, we need to sharpen our understanding of monetary policy risk management. Uncertainty is clearly relevant from a policy standpoint. But do policymakers systematically monitor uncertainty? Moreover, do they disagree on the economic outlook, and if so, does this influence their decisions? Third, we need proxies for uncertainty for a broader set of countries than the G7. For example, how does uncertainty evolve in a country like New Zealand as opposed to, say, the United States? This special issue addresses all these questions. The first paper, ‘Yield curve and financial uncertainty: Evidence based on US data’, estimates the response of the US yield curve to a jump in financial uncertainty. I address this question by conducting a local projection analysis with US monthly data from 1962–2018. I find both ends of the yield curve respond negatively and significantly. The response of the short end of the yield curve is stronger than that of the long end, that is, a financial uncertainty shock causes a temporary steepening of the yield curve. This result is consistent, among other interpretations, with medium‐term expectations of a recovery in real activity after a financial uncertainty shock.

Population balance modelling of bubble columns under the heterogeneous flow regime

Industrial bubble columns generally operate under the so-called heterogeneous regime and with high gas volume fractions, implying a fundamental role of the coalescence and breakage phenomena. These columns are usually simulated thanks to Eulerian CFD modelling, whereas the local bubble size distribution can be estimated with population balance models. The coupling can be realized with the Quadrature Method of Moments in order to minimize the CPU time consumption. In this work, the CFD-PBM/QMOM approach is validated using experimental data. Various qualities of water and two spargers are investigated. Considering different additives and spargers allow studying separately the effect of breakage and coalescence. In particular, a perforated plate with many holes leads to the formation of small bubbles that hardly break. On the contrary, a perforated sparger with a few big holes induces the production of big bubbles in the lowest part of the column, enhancing breakage. In this second case, due to breakage, bubble size decreases quickly along the axial position until an equilibrium bubble size is reached. The presence of additives is used to further investigate coalescence and breakage phenomena, given that it generally suppresses coalescence and highlights the kinetics of breakage. In this work, a suitable set of breakage and coalescence kernels is proposed, capable of providing predictions in good agreement with experimental data for different bubble columns geometries, gas flow rates and additive concentrations.

Crustal versus mantle origin of carbonate xenoliths from Kimberley region kimberlites using C-O-Sr-Nd-Pb isotopes and trace element abundances

Carbonate-bearing assemblages in the mantle have been interpreted to be the source for Si-undersaturated, CO2-rich magmas, including kimberlites. However, direct evidence for carbonate in the mantle is rare in the contemporary literature. Here we present petrography, trace element, and C-O-Sr-Nd-Pb isotope composition for a suite of carbonate xenoliths from the Kimberley region kimberlites to ascertain their mantle or crustal origin and gain insight to the potential for the occurrence of carbonate in the mantle. Carbonate xenoliths were found in large kimberlite blocks from the Bultfontein kimberlite and Big Hole region. The xenoliths are characterised by pale green alteration margins made of fine-grained microlites of an unknown mineral as well as spherules surrounded by glassy material. They are generally 1–4 cm in size, coarse-grained (1–2 mm), and comprised entirely of calcite.Carbonate xenoliths from the Bultfontein kimberlite have low total REE concentrations (0.2–4.9 ppm), constant 87Sr/86Sri (0.7047–0.7049) combined with variable ƐNdi (−0.1 to −26.2) and 206Pb/204Pbi, 207Pb/204Pbi, and 208Pb/204Pbi of 16.7–18.8, 15.3–15.6, 36.5–38.4, respectively. Xenoliths from the Big Hole sample have higher 87Sr/86Sri (0.7088–0.7095), lower ƐNdi (−24.5 to −3.8), and 206Pb/204Pbi, 207Pb/204Pbi, and 208Pb/204Pbi of 18.9–19.9, 15.7–15.8, 38.4–38.8, respectively. The δ13C values for both Bultfontein (−5.7 to −6.6‰) and Big Hole (−4.7 to −5.4‰) carbonates are within the typical range expected for mantle-derived carbonate. The δ18O values (15.5–17.5‰) are higher than those of mantle silicate rocks, indicative of late-stage low-temperature interaction with fluids; a common feature of groundmass calcite in the Kimberley kimberlites.The Sr- and C- isotope composition of the Bultfontein xenoliths indicates a mantle origin whereas the Big Hole xenolith Sr- and C-isotopes are more ambiguous. Isotope mixing models are inconsistent with interaction between the host kimberlite and carbonate xenoliths. Correlation between ƐNdi and δ18O values for the Bultfontein xenoliths indicates late-stage interaction with low-temperature fluids, which may also be responsible for the large range in ƐNdi. This in turn indicates that the highest ƐNdi of −0.1 represents the primary carbonate xenolith signature, and this value overlaps typical Group I kimberlites.We discuss two possible origins for the carbonate xenoliths. (1) Carbonate xenoliths from the sub-continental lithospheric mantle (SCLM), where quenched margins and the large range of ƐNdi are related to formation in the mantle. (2) Carbonate xenoliths from an earlier phase of carbonatite magmatism. The similarity of isotope signatures of the Bultfontein carbonates to Group I kimberlite may further suggest a link between kimberlite and carbonatite volcanism such as observed elsewhere in the world.

IDENTIFIKASI JENIS CACAT KAYU BULAT JATI (Tectona grandis Linn. F.) PADA AREAL PEMANENAN DI KPH JEMBER

Teak trees are high-quality plants.The activity of harvesting teak doesn’t always produce good quality or without defects found.Various types of defects will reduce the quality and selling value of wood.The purpose of this research was to identify and measure the defects of teak roundwood (Tectona grandis) in the harvesting area in KPH Jember. Knowing the type and quantity of defects is expected to be a reference for companies, especially Perum Perhutani, KPH Jember on process of maintaining teak trees during harvesting, get better results and higher value results. The method that was used in this research was quantitative descriptive research and go to the research site.Sampling is done bypurposive sampling. The research was conducted in March - April 2018. The results of the identification of teak defects (Tectona grandis Linn.F.) found 23 types of defects that was form defects , body defects, or bontos defects. The type of defect found is straightness, cylindrical, backwardness, groove defects, direction of fiber defects, inger-inger, buncak-buncak, hole gerek, broken defects, hole in the body, wood eye, lump defects, lengar defects, broken up defects, slemper defects, bontos defects, fragile terrace, rotten terrace, hole defects, gubal defects, pakah defects, gabeng defects, dan kunus defects. The most defects were the type of buncak-buncak light as 89 trees (98.89%) and 566 sortiment (56.39%) that having defects, while the least defect were type of big hole gerek as 2 trees (2.22%) and 3 sortiment (0.30%) that having defects.Keywords : defect, harvesting, identification, perhutani, teak.

High Sensitive Methane Sensor With Temperature Compensation Based on Selectively Liquid-Infiltrated Photonic Crystal Fibers

A highly sensitive and temperature-compensated methane sensor based on a liquid-infiltrated photonic crystal fiber (PCF) is proposed. Two bigger holes near the core area are coated with a methane-sensitive compound film, and specific cladding air holes are infiltrated into the liquid material to form new defective channels. The proposed sensor can achieve accurate measurement of methane concentration through temperature compensation. The sensitivity can reach to 20.07 nm/% with a high linearity as the methane concentration is within the range of 0%–3.5% by volume. The proposed methane sensor can not only improve the measurement accuracy, but also reduce the metrical difficulty and simplify the process.

Intrusion Detection in Cloud Computing Environment Dynamic Remote Surveillance Scheme

Cloud Computing, a part of the Tech-Revolution that has attracted huge crowd giving them cost -effective solutions for managing their data and at the same time helping them reach out to the world, is deepening its roots with help of some genius mind in the industry but nasty human practices leave a big hole in the security offered by the technology which is the cause of big concern. Many solution including IDS and IPS are being continuously reached about and implemented to fill this hole. So here, we discuss yet another IDS aiming to fill out the flaws in existing solutions and enhancing security in cloud computing the proposed solutions uses remote logging and monitoring scheme wherein a trusted thisrd party keeps surveillance on server hosting VM'S AND OTHER USER SERVICES, thus IN CASE OF Instructions or breaches which can be initiated thus preventing important data access by outsider. Implementation shows that this system can resist many known and latest attacks providing cost-effective and easy solutions.

The new NHS Patient Safety Strategy has a big hole in it

The new NHS Patient Safety Strategy has a big hole in it

Exploiting Multi-Direction Features in MRF-Based Image Inpainting Approaches

Image inpainting technique recovers the missing regions of an image using information from known regions and it has shown success in various application fields. As a popular kind of methods, Markov Random Field (MRF)-based methods are able to produce better results than earlier diffusion-based and sparse-based methods on inpainting images with big holes. However, for images with complex structures, the results are still not quite pleasant and some inpainting trails exist. The direction feature is an important factor for image understanding and human eye visual requirements, and exploiting multi-direction features is of great potential to further improve inpainting performance. Following the idea, this paper proposes a Structure Offsets Statistics based image inpainting algorithm by exploiting multiple direction features under the framework of MRF-based methods. Specifically, when selecting proper labels, multi-direction features are extracted and applied to construct a structure image and a non-structure image, and the candidate labels are chosen from the offsets of structure and non-structure images. Meanwhile, the multi-direction features are applied to construct a new smooth term for the energy equation which is then solved by graph-cut optimization technology. Experimental results show that on inpainting tasks with various complexities, the proposed method is superior to several state-of-the-art approaches in terms of the abilities of maintaining structure coherence and neighborhood consistence and the computational efficiency.

Application of Stimstream Shaped Charge with Consistent Entrance Hole and Deep Penetration in Shale Gas Reservoir

To address the issues of inefficient hydraulic fracturing on perforation clusters in shale gas horizontal wells caused by the inconsistent size of entrance holes on the casing, Stimstream shaped charge providing consistent hole and deep-penetration was introduced and its special performance was analyzed. Surface concrete target test and field test were conducted respectively to compare the performance between this kind of charge and conventional deep penetration charges made in China. In surface concrete target test, the average hole diameter of Stimstream shaped charge in 0°, 90°, 180°, 270° phasing is 9.4mm, 9.3mm, 9.3mm, 8.9mm, the average hole diameter of conventional deep penetration charges in 0°, 90°, 180°, 270° phasing is 9.3mm, 8.6mm, 6.5mm, 7.0mm respectively. The results shown that Stimstream shaped charge can provide uniform and big holes on the casing regardless of different clearance between perforating gun and casing. In three field testings, comparing the field data of S3406D Stimstream charge and domestic SDP35HMX25 shaped charges, it proven that S3406D can reduce the average hydraulic breakdown pressure by 2044.5 psi, 1189psi and 1261.5psi respectively, and reduce the average treatment pressure to pump proppant by 696psi, 652.5psi and 928psi respectively. It has remarkable effectiveness on reducing the breakdown pressure and treatment pressure of shale gas formations during hydraulic fracturing operation.

The effect of decontamination procedures on elastic polymeric materials used in dental mouthguards fabrication

Mouthguards are commonly used in the prevention of head and mouth injuries in many sport disciplines. Elastic polymeric materials used in their fabrication absorb the energy of impact. However, decontamination procedures may cause damage to their surface causing deterioration of their properties and favouring pathogen colonization. The aim of the study was to determine the impact of different cleaning methods on mouthguard materials, surface quality. The material for the research consisted of 81 samples made from polymeric materials used for custom mouthguard fabrication - Impak, Corflex Orthodontic and Erkoflex. Samples were viewed under a scanning electron microscope after exposure to different cleaning methods. Statistical analysis of tested decontamination procedures and disinfecting agents showed statistically important ( p < 0.05) results for the presence of small and big separated pieces, grooves and holes. Out of all the cases the lowest indicator for occurrence was in the disinfecting spray - Aftermat. Considering the importance of the surface material of the mouthguard, disinfection should be the method of choice for maintaining its hygiene. Impak material samples, cleaned with the Aftermat spray, showed the lowest range of damage.

Enhancing fouling mitigation of submerged flat-sheet membranes by vibrating 3D-spacers

Unsteady-state shear is acknowledged to be more energy-efficient in the mitigation of membrane fouling. In this study, we aimed to understand the effects of three dimensional (3D)-spacer configuration and their vibrating orientation on the extent of fouling mitigation in a submerged flat-sheet membrane microfiltration (MF) system. Several types of 3D-spacers were designed and computational fluid dynamics (CFD) was used to simulate the shear and turbulence along the membrane surface induced by vibrating 3D-spacers. The designed 3D-spacers were produced by 3D printing technique and their fouling control efficiencies were experimentally examined in a submerged flat-sheet membrane MF system with bentonite and sodium alginate as model foulants. Both simulation and experimental results revealed that the wave-like spacer (groove direction vertical to spacer movement direction) could alleviate more membrane fouling than the other designed spacers (e.g., hill-like spacer, wave-like spacer with groove direction parallel to spacer movement direction), regardless of tested permeate fluxes. Furthermore, two types of wave-like spacers were designed based on CFD simulation, in which perforation were placed on the spacer in order to enhance shear rate and provide a path for the back transport of foulants into the bulk feed. The MF membrane tests showed that the presence of either big holes (2 mm diameter) or small holes (1 mm diameter) could not benefit to reduce membrane fouling at a lower permeate flux (20 L/m2h), but the presence of small holes significantly improved membrane performance at a higher permeate flux (40 and 60 L/m2h).