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Swallowing of large objects and humans by quicksand fascinated writers for long time. Previously, it was believed that sand must contain liquid to achieve such characteristics. However, recently it has been proposed that even undampened loose sand (like in deserts) can swallow large objects and investigated in this paper. In this study, numerical simulations are performed using computational fluid dynamics (CFD) and discrete element method (DEM). The transition from packed to quicksand like state in granular material is obtained by passing gas near to minimum fluidization velocity and keeping bed stationary. It is observed in simulations that dry quicksand acts more like a fluid and the granular drag force due to penetration of intruder becomes isotropic and depth independent which is a deviation from packed bed. At the end of paper, the physics behind this behavior is explained by comparing force chains formed in packed and dry quicksand.

Self-compacting concrete (SCC) mix designs exhibit complexities in their mechanical properties due to composite nature of the material and the multitude and variety of factors that affect such properties. In this paper, a set of SCC mix designs are made using silica quicksand (as filler) instead of rock powder with other required materials. The tests of fresh concrete such as the slump flow, J-ring, V-funnel, L-box tests and the hardened concrete tests are investigated and considered. The tests results are shown that, a high quality has been achieved for SCC mixture contains the quicksand and silica fume contents with low lubricant admixture dosage. The research is embodied the use of a branch of Artificial Neural Networks (ANN) as a quick and reliable alternative to such experimental testing. Results show that the ANN technique can perform as a satisfactory alternative to experimental testing to provide speedy prediction of optimum silica quicksand content must be added prior to SCC mix design. As such, proposed method for the SCC mix design are limited in scope and are approximate at best as they must rely on the results of experimental tests, which are both costly and time-consuming to perform.

Tidore Islands has the potential of natural resources in the form of the availability of plenty of floating sand. This study was conducted to determine the effect of the use of floating sand as a substitute for sand on the characteristics of asphalt concrete mix wear (HRS-WC). This study uses the methods of The Asphalt Institute, Indonesian National Standards (SNI), and General Specifications 2018-Section 6.3. Percentage variation used in replacement material is 15% of normal sand: quicksand 15%, normal sand 7.5% : 7.5% quicksand, normal sand 11.25% : 3.75% quicksand and sand floating 11.25% : normal sand 3.75%. For find out the Marshall characteristics of the HRS – WC (Hot Rolled Sheet-wearing course) mixture by using a substitute for floating sand aggregate. Results of testing marshall with sand floating 11.25% sand normally 3.75% indicates the value of the stability of the highest = 1361.43 on levels of bitumen 6%, sand normal 15% to the value of the stability of the highest = 1408.6 at the level of asphalt 5.5%, the highest stability value = 1435.9 at 7% asphalt content, the highest stability value = 1472.2 at 6.5% asphalt content, and the highest stability value = 1687.8 at 6% asphalt content. And the average value of stability is 1473,19.

This article re-examines Nella Larsen’s Quicksand (1928), a major Harlem Renaissance and African-American literary canon novel, against the tendency to focus on it as a tragic mulatta story. Instead, I argue that Larsen—like African-American authors dating back to Charles W. Chesnutt and Pauline Hopkins of the turn-of-the-century—challenged the trans-Atlantic racial exceptionalism by using a far more expansive critical lens that recognized a different mode of being. This being, defined by the literary category of the grotesque (popular in the 1920s and 1930s), recognizes ancient (African) times and a biomorphic mode in which humans, animals, and nature overlapped ontologically. The unique aspect of this article is that it reveals how Larsen also taps Danish literature as part of her critique of normative modern modes of thought, esthetics, politics, and spirituality. Ultimately, Larsen uses Quicksand to expose Western myths, including the stork myth, as deleterious to the more ancient myths that she excavates.

A quicksand disaster through a borehole occurred in Longde coal mine. A lot of aeolian sand, the volume of which is between 310,000 m3 and 380,000 m3, has submerged into the underground space in about 70.5 h. The volume flux of quicksand cannot be calculated accurately by the empirical method. Based on the method of fluid mechanics, an all-purpose computing method for quicksand disaster through a borehole was proposed. The result shows that the inrush volume of sand into underground space was between 310,000 m3 and 350,000 m3, which was consistent with the actual result. To apply and popularize this method, the impact laws of water yield properties of an aquifer on the volume flux were discussed. The all-purpose computing method can be suitably used for the volume flux calculation of quicksand disaster through the borehole.

There are some quirky books around — I read one recently about ‘worst-case scenarios’. There were chapters about how to fend off a shark in the water or how to escape quicksand. It left me wondering what to do if I were attacked by a shark while stuck in quicksand! I think these books are supposed to be light-hearted but a part of me wonders if people might actually use them as reference books. In today’s society ‘what if’ and ‘catastrophe thinking’ are everywhere. Worse perhaps are those poor modern parents, where thoughts of the worst outcomes seem to dominate their whole consciousness. The fear of not breastfeeding until the child is 5 years of age, the …

In coal mining, a poorly sealed borehole is one of the channels that can lead to an inrush of water and quicksand movement, seriously compromising the safety of the coal mine. In this paper, we used the water inrush and quicksand incident at Longde Coal Mine as an example in order to investigate the mechanism of water inrush and quicksand movement induced by a borehole, as well as to develop measures for the prevention and remediation of such problems. Two sand funnel models and a water inrush outlet model are introduced from which to calculate the flow of the water and quicksand; a comparison of the two shows that the flow predicted by the water inrush outlet model is more consistent with observations from the accident than the sand funnel models. Based on the water inrush outlet model, the aquifer thickness and borehole diameter are the two key factors affecting the flow. The aquifer channel is inferred as tubular, with its diameter gradually decreasing from ground surface to underground, and a time-dependent surface subsidence model is constructed. Finally, we develop a prevention method, “Prior to mining development, borehole should be investigated and plugged for prevention,” and propose a remediation method, “Changing the pipeline flow into fracture flow, followed by changing the fracture flow into pore flow, and finally grouting and plugging.”

Underground space is becoming increasingly more utilized in the fast urbanization process of Shanghai. However, many geoenvironmental hazards, including land subsidence, slip flow, methane gas, piping, and quicksand, are occurring more frequently, as underground space development enters the state of “big, deep, long, fast, and dense.” In this paper, based on our investigation and studies of construction project cases, we analyze the possible factors causing geoenvironmental hazards and propose corresponding measures for their prevention. From the viewpoint of earth system science, the geoenvironmental hazards are caused by anthropogenic factors coupled with natural factors. Shanghai is built over layers of soft soil that were deposited during the Holocene. The paleogeographical environment of the Holocene produced soft soil with high water content, large void ratio, high sensitivity, thixotropy, low shear strength, and high compressibility; these characteristics lead to a geoenvironment that can be easily disturbed by underground engineering construction. To achieve sustainable development of underground space, a series of prevention and control measures are presented, especially awareness of the need for geoenvironmental protection and risk management should be enhanced, as well as incorporating technology including global positioning system, geographic information system, and synthetic aperture radar interferometry, and information construction in underground development projects.

To study the behavior of overlying strata and the likelihood of water inrush and quicksand with different mining sequences under an unconsolidated alluvium aquifer, a numerical model based on the fluid-solid coupling theory was constructed by FLAC3D. Simulation results revealed that the mining sequences had a significant influence on the seepage, displacement and failure characteristics of the overlying strata. In this kind of geological and hydrogeological conditions, the workface close to the outcrop of coal seam easily suffers from water inrush and quicksand during mining. In the simulation results, the plastic zone, vertical displacement and pore water pressure in the overlying strata of the workface decrease more or less using the upward mining sequence than using the downward mining sequence. Therefore, the application of the upward mining sequence in the process of mining is preferential to prevent water inrush and quicksand.

Sci-Hub has shaken the pillars of scholarly publishing, providing free access to millions of paywall-protected scientific articles. Along the way, it has also challenged the hegemony of major publishers and a system propelled by scientometrics. Here we posit a scenario in which the myriad of papers offered by Sci-Hub could trigger a sudden flip to gold open-access, dragging authors into an even more restricting paywall.

This session presented a case study of one library's move to a discovery layer in the catalog in order to help users discover and access electronic resources. The presenters described the entire process of evaluating the Online Public Access Catalog (OPAC) and deciding which provider to choose for the discovery layer. Both presenters shared strategies and decision-making methods with the audience.

Large diameter fully cased wells that gain water from the bottom are often dug in sandy and collapsible aquifers. They have cylindrical vertical walls lined with brick or concrete. The well bottom is partially filled with aquifer material through which the flow is vertically upward. When the vertical hydraulic gradient reaches a critical value, quicksand occurs and the well structure can be destroyed. Another difficulty encountered is drawdown in the wellbore and the drying up of the well. To overcome these problems, the flow around and beneath these wells is numerically simulated. The simulation results are used to investigate the effect of well and aquifer parameters on quicksand and drawdown. For practical purposes, the dimensionless drawdown-time and dimensionless vertical gradient-time curves are developed. It was found that the ratio of filling material thickness to well radius affects the shape of these type curves. The type curves may be used to predict the time after pumping commences when quicksand occurs and the well dries up. They are also useful to design the safe pumping rate and duration as well as the optimum well radius. These are demonstrated by analyzing the pumping test data from a case study in the arid Chah Kutah region, southern Iran.

I grew up in the seventies, back when we didn't use seat belts—we barely used car seats. Riding around in the back of a pickup truck was not thought to be a dangerous activity. One of the things I miss the most about the seventies is the television programs. Maybe it’s because we only had three channels (four if you were good with aluminum foil). One of the things I remember from those programs is quicksand. I personally have never experienced quicksand, but it was everywhere on television. You’d be minding your own business, and the next thing you know you are in quicksand. As I remember things, the more you struggled, the faster you sank. You had to call for help. Somebody needed to pull you out.

“With a missing child dominating the headlines this summer, and reports that due to obesity our children may not outlive their parents, the question of protecting the next generation is high on the news agenda,” writes media lawyer Melville-Brown. “But it is not just the physical health and well-being of children that is at stake in our modern society. The public’s appetite for news – serious or gossip – and photographic evidence of both, together with the media’s preparedness to feed this hunger, is putting our children at risk of media over-exposure.” So who, she asks, is looking after the children: parents, courts, government or the media? And concludes: “For their own very different reasons, they all must.”

The authors would like to thank the discusser for his interest in the paper. We are familiar with the discusser’s previous work and are pleased he has shown interest in our research and paper. The discusser mentions quicksand tanks and the modeling of heave of sandy soils, pointing out that critical gradients measured in these laboratory tests were consistent with gradients calculated using Eq. (1) of the paper. The discusser also comments on the USACE’s field experience with vertical critical gradients needed to initiate boils (presented in Fig. 2 of the paper) along with his own data and attributes the lower observed gradients to concentrations of flow caused by imperfections in the soil. The authors agree with this assessment, illustrating the concentration of flow into a blanket defect in Fig. 1. However, the authors’ intent was not to model the heave mechanism but to model the initiation of soil movement into a void such as what takes place at the base of a defect in an overlying blanket (defect in the blanket as shown in Fig. 1). Soil movement in this case would not occur due to the heave mechanism but through deformation of the soil mass and individual grain movement into the void. It should also be pointed out that heaving of sand in liquefaction tanks and formation of sand boils through a blanket defect occur due to very different mechanisms. Terzaghi and Peck (1948) showed that heave of sand occurs due to upward seepage forces acting against the buoyant weight of the soil. Eq. (1) of the paper is based on Terzaghi’s theory and produces gradients similar to the liquefaction tests referenced by the discusser. The formation of sand boils through a blanket defect is a much more complex phenomena, consisting of migration of sand grains (individually or in mass) through the defect. The mechanisms of initiating this movement are complex and are the focus of our laboratory testing and the subject paper. The discusser asserts that the vertical gradients measured in the study are higher than those estimated by Eq. (1) due to the highfriction interface on the sides of the sample holder along with interference from the instrumentation in the sample holder. The authors agree with this assertion but would like to point out that the friction on the sampler sides was intentional in order to prevent heave and model the deformation of the soil mass and individual grain movement at the top of the sampler. [In fact, preliminary tests were performed at the initiation of this study without the silicon coating and correlated well with gradients predicted by Eq. (1).] This was done in order to assess how piping will initiate into a void of limited size; such as a defect in an overlying blanket (Fig. 1) or a hole in a conduit, to name a few. The friction on the sides of the sampler was meant to model friction with the adjacent soil that is overlain and retained by blanket material, thus, preventing heave of the soil mass below the void. Our model differs from the conditions depicted in Fig. 1 in that the gradient across the sample is uniform in lieu of the converging and concentrating flow conditions shown in Fig. 1. This too was intentional so that the gradients at which the various stages of observed behavior occur could be assessed. After presenting the results of the tests, the authors discuss how the results and observations from our experiments relate to field conditions (see “Application to Field Conditions” section of the paper). In this section we present a scenario and describe how the four stages of soil movement observed in our experiments could be manifested in the field and illustrate this in Fig. 11. Obviously, because the soil is eroding and deforming into a defect of limited size, heave of the soil mass does not occur and friction between the moving soil and the adjacent retained soil does exist. The discusser also mentions the limited size and height to diameter ratio of our sample holder and points out that it is much greater than that used in the quicksand tests. He also points out that soils with higher friction angles reflect the friction effect with higher gradients required to develop the stages of piping development. Again, because we are modeling erosion into a defect of limited size we are not modeling the heave mechanism for which a small height to diameter ratio would be desired. The authors do understand that the size of the opening will affect the ability of the soil to arch across the void and will, thus, affect the behavior. Because of this we have performed tests using samplers with larger diameters as part of our ongoing research. These tests are allowing us to assess the effects of soil arching on the mechanisms discussed in the paper. We are also performing tests on inclined samples to assess the effects inclined seepage exit faces may have on this erosion mechanism. The results of these tests will be presented in subsequent papers that are under development. In conclusion, the experiments presented in the paper were designed to model a mechanism of internal erosion quite different from the heave mechanism that is referenced by the discusser. Our experiments resulted in vertical gradients that are higher than those observed in “quicksand tests” and the average gradients observed in the field. However, the increased gradients do not include the effects of converging flow that would also be observed with the mechanism being studied. Such converging flow would tend to increase the gradients at the point of erosion. It is the opinion of the authors that the vertical gradients observed by the USACE in the field are average gradients that are concentrated and increase substantially as the flow approaches the defects. The concentrated gradients act on the soil that is supported by side friction and arching that results in greater resistance to movement than the heave equations would predict. Thus, the wide range of average gradients presented by the USACE is the result of the effects of the flow concentration and the arching effects cancelling out to varying degrees. The discusser expresses concern that the results presented are “seriously inconsistent in the nonconservative direction.” The authors concur that if the results were applied to the wrong conditions they would be very nonconservative. However, a discussion of scenarios of where and how the results are applicable are presented in the paper and should prevent the inappropriate use of our results. The challenge does come in applying our results to a field situation. To address this challenge we are collaborating with a numerical modeling specialist who will be modeling our experiments with

There have been records of failures and quicksand conditions in boreholes in recent times impeding the performance and operation of boreholes which may have resulted from various factors ranging from construction problems, drilling inaccuracies, fitting and installation problems, some chemical effects within the aquifer medium etc, but it has been ignored that a factor of great benefit to the operation of water boreholes; seepage force could get to a considerable which becomes unsafe for the well operation thereby causing dislodgement of sand particles and sandstones resulting boiling. This research work has investigated the contribution of contact force and seepage force to the failure of boreholes. This necessitated the use of combined finite-discrete element method to generate model expressions from contact and seepage forces considered to be the major forces contributing to the flow of fluid through soil mass and boiling or quicksand effect results when seepage force becomes more in effect under critical hydraulic gradient and / or critical hydraulic head. A mathematical/laboratory model was used and an expression for calculating the critical hydraulic head causing critical seepage deduced as = and the equilibrium model has deduced an expression for the safe hydraulic head during well pumping as = . These have been verified using a laboratory investigation; borehole prototype well failure test. It has been established that there is strong agreement between model result and the laboratory study result from the correlation analysis conducted which has shown correlations of 1.00975 and 0.989879999701 for the critical state condition and equilibrium state condition respectively. For purposes of future calculations, borehole performance monitoring and designs, the standard critical hydraulic head of the system from Table 3 and Fig.7 is 2.92E-8 which has the strongest agreement with 2.59E-8 of the laboratory study with a deviation of 3.3E-9. The deduced models can be used to design and monitor the performance of boreholes. For safe pumping and corresponding yield in the bore hole system, inter-granular force between granular particles should equal the seepage force and this is achieved by ensuring that the deduced model expression is used to determine the safe hydraulic head. Finally, irrespective of the fact that an increase in hydraulic head increases discharge, the system should be operated at a head safe for the performance of the well and as long as the model hydraulic head expression deduced is used under the above conditions, safe pumping can be achieved at any voltage between 150volts and 240volts. http://dx.doi.org/10.4314/njt.v34i3.32

This article reviews a central strand of the literature on legislative decision-making in the European Union (EU): procedural spatial models. These models have gained increasing prominence during the last decade of scholarship on the EU and have considerably enhanced our understanding of the EU legislative decision-making process. However, the literature has not been without criticism and has reached a stage of theoretical stagnation. The intention of this article is twofold: first, it reviews the existing procedural spatial literature and critically discusses the lack of specification and justification of some of its key assumptions, especially those concerning actors' preferences and the characteristics of the decision-making process. In a second step, it will be argued that it is necessary to re-evaluate some of the central assumptions of procedural models. In particular, future research needs to study mechanisms of preference formation and decision-making, i.e. aggregation of preferences, within EU legislative bodies.

Grain storage containers not only present inherent dangers to the operators, but also to the rescuers if someone falls in. Here we report the rescue of a patient from a grain container using a novel technique involving a cylinder placed around the patient. This allowed the grain to be sucked out from around the patient and enabled his rescue uninjured. The rescue action was complicated by acute chest pain in the patient while he was submerged in the grain, and a severe asthma attack in the emergency physician. The rescue and the dilemmas encountered are described together with a review of the relevant literature.

Finding participants for experiments has always been a challenge. As technology advanced, running experiments online became a viable way to carry out research that did not require anything more than a personal computer. The natural next step in this progression emerged as crowdsourcing became an option. We report on our experience of joining this new wave of practice, and the difficulties and challenges we encountered when crowdsourcing a study. This led us to re-evaluate the validity of crowdsourced research. We report our findings, and conclude with guidelines for crowdsourced experiments.

As scholars and expert practitioners, we portray globalization and technological innovation as key drivers for a new industrial age. We herald the dawn of an “information revolution,†a new economy revolutionizing the organization of production and distribution, an upheaval of long-stead technical, political, and economic institutions of our society. But as information professionals, how well equipped are we to explain and predict — much less lead — this revolution? On what foundation do we stake our claim as knowledgeable experts? Today I want to discuss with you just this issue.

F racking : A n I ndustry U nder P ressure B S J Jo Melville T hree miles beneath the surface of the earth and at pres- sures exceeding one thousand atmospheres, a complex concoc- tion of chemicals spurts, rupturing stone and cracking sheet rock through sheer force. As fractures creep out from the shattered bedrock, the fluid continues its destructive course, splitting millennia-old stone as if it were soft timber. As the pressure ebbs away further from the epicenter of the event and the initial pressure surge subsides, the wash of gushing liquid gives way to a tide of granular particles almost like a wave of quicksand. The particulate matter penetrates deep within the myriad ruptures, wedging them open so that the rocks themselves can release their precious bounty -- energy- rich shale gas trapped between layers of stratified rock. T he process that has just taken place is known as hy- draulic fracturing, but is far more ubiquitous under a differ- ent name -- fracking. Fracking has had its fair share of the media spotlight recently, with innumerable reports and studies showing that it taints everything from our atmosphere to our water tables while similar amounts of reports and studies declare it not only perfectly safe, but vital for the stability of the energy economy. Both sides have convincing evidence and plenty of scientific clout; it is very likely that neither side is completely right. Whatever the case, it is vitally important that we acknowledge the benefits and consequences of hydraulic fracturing. Because of its vital importance to the extraction of natural gas and oil, both central tenets of the energy indus- try, banning fracking could hugely destabilize energy prices. However, if fracking is polluting our air and water, allowing it to continue could be even worse. To fully understand the con- troversy behind fracking, it is necessary to understand what it is and how it works. H ydraulic fracturing is a method of treating wellbores to increase the production rate and efficiency of collection of resources. It is most commonly used to increase the yields of natural gas or oil mining operations, though adapted versions of the process see insignificant amounts of usage harvesting more exotic resources (Brown, 2007). True to its name, it works by pumping highly pressurized fluid into a borehole, causing ruptures in the side of the well through which gas or oil can seep in, which are often wedged open using a granu- lar “proppant” to facilitate flow through the fissures. While fracking has existed commercially since the 1960s, prototypi- cal forms of the process date back to over a hundred years before that (Montgomery & Smith, 2010). In its long lifespan, fracking has been fine-tuned dozens of times by hundreds of innovative new processes, chemicals, and instruments that allow it to drastically increase the yields of wells. While many regulatory agencies have and continue to consider fracking a safe process, some recent studies (and indeed, reported contamination incidents) make it seem ever more likely that fracking is far from the golden boy of the energy industry that it was once thought to be. Even now, several govern- ments around the world have passed legislation restricting or banning the use of fracking, and it is increasingly possible that we may see it phased out altogether. I t is almost laughable to compare fracking in its historic sense to the modern usage of the term -- indeed, the sheer scale of the growth of the process boggles the mind. While early fracking treatments in the 1950s used on the order of 750 gallons of fluid to rupture the rock and 400 pounds of sand to prop open the fractures, some of the largest modern fracking treatments can exceed 1,000,000 gallons of fluid and 5,000,000 pounds of proppant (Montgomery & Smith, 2010). While much of this vast increase in scale is due to increased demand for fuel and larger wells, a large extent of it is due to a clearer understanding of the mechanics of fracking, a gradual and unending perfection of the process, and a better sense for the maximum amount of fracking that is cost-efficient. It is easy to think of modern fracking as a science, and like all sciences, fracking evolved from highly disorganized roots through careful observation and improvement. I n 1865, Lieutenant-Colonel Edward Roberts, inspired by memories of artillery from the Civil War, christened his “Explosive Torpedo”, a gunpowder-filled iron shell with an explosive tip that would detonate upon a firm impact. By filling an oil well with water, then deploying and detonating a torpedo in the well, Roberts was able to utilize the power of the explosion to carve fissures into the rock well in a process he called “superincumbent fluid tamping” (Montgomery & Smith, 2010). In the years that followed, roughneck oil workers in New York, Pennsylvania, and West Virginia often employed nitroglycerine, a potent explosive, to increase the yields of shallow, hard oil wells. By disintegrating substantial portions of the oil-containing structures, the workers hoped to increase the flow of oil to the well and the total amount of 22 • B erkeley S cientific J ournal • S tress • F all 2013 • V olume 18 • I ssue 1 •

It was so easy and so pleasant to think about freedom and cities, about clothes and books, about the sweet mingled smell of Houbigant and cigarettes in softly lighted rooms filled with inconsequential chatter and laughter and sophisticated tuneless music. It was so hard to think out a feasible way of retrieving all these agreeable, desired things. Just then. Later. When she got up. By and by. She must rest. Get strong. Sleep. Then, afterwards, she could work out some arrangement. So she dozed and dreamed in snatches of sleeping and waking, letting time run on. Away.

This 1994 article by Jeffrey Gray originally appeared in the journal NOVEL: A Forum on Fiction (Duke University Press). An early foray into transnational American Studies, Gray’s analysis of the role “Europe” plays both in the narrative and in the life of the author herself begins with a discussion of the object of art—the self as exoticized, distanced other—imagined and displayed against the carceral black body in the American imaginary, an imaginary that holds the protagonist, Helga, hostage to an indeterminacy represented by her mulatto status. Gray argues that the “quicksand” of the search for essence, whether located in the body or in the eyes of others, eventually dissolves the protagonist’s sense that a change of place can change the truth that essence does not exist. Gray references the shared observation among African American international celebs (Richard Wright, James Baldwin, and Josephine Baker—whose 1973 interview with Henry Louis Gates, Jr., is cited) that “being different is different” in Europe, yet that otherness is finally also not an experience of self, which the narrative (and perhaps the author’s life as well) proves to be endlessly deferred.

In 2011, the example that breakwaters collapsed because of the basic ground’s destabilization was reported by Tohoku-Kanto earthquake tsunami. Fluid-Structure-Soil coupling simulation is desired for a systematic comprehension of the breakwater collapse mechanism, and it may help to develop next disaster prevention method. In this study, A particle simulation tool based on the SPH has been modified and improved to analyze seepage flow and soil scouring. In seepage flow analysis, as a first step, this simulation treat the surface flow and seepage flow interactions by using governing equation. In the scouring analysis, soil scour is judged by an empirical criteria based on quicksand quantity formula.

Published to critical acclaim in 1928 and praised by W. E. B. Du Bois as the “best piece of fiction that Negro America has produced since the heyday of Chesnutt,” Larsen's Quicksand has since been criticized for its focus on the narrow world of the black bourgeoisie. But her treatment of race, gender, and culture is far more complex than these pronouncements suggest. This essay shows how Larsen's emphasis on the aesthetic—objets d'art, clothing, fabrics, decor—highlights problems of cultural constructs and self-representation. Often compared with her prolific contemporary Jessie Fauset, Larsen goes beyond Fauset in both stylistic experimentation and psychological insight, daring to explore the failure of her protagonist to transcend cultural concepts of race and gender at a time when one-dimensional success stories were the rule in black women's novels of racial uplift.

Ever fallen into quicksand? Ever felt those minutes drag into days? Children have shorter attention spans than most adults – and are easily distracted. Sometimes we wish their endless energy could be directed into overcoming learning stumbling blocks instead of running us dizzy.

In an article that forms part of the PLoS Medicine series on Big Food, Kelly Brownell offers a perspective on engaging with the food industry, and argues that governments and the public health community should be working for regulation, not collaboration.

Fitzpatrick argues against legalising assisted dying.1 The argument is partly built on quicksand. Particularly when referring to empirical fact, the water becomes turbid. When he argues that older disabled people’s lives are under …

Times are tough for the Spirit rover. Last week, in its 5th year of exploration, Spirit became mired in a dry martian version of quicksand. Mission engineers are studying how it might extricate itself, but the crisis raises a perennial question: When, if ever, should a mission in its declining years be put out of its misery? When does the diminishing science output no longer justify the millions of dollars it costs?

Artificial freezing of ground by refrigerating machines requires considerable power and expense, so it is comparatively seldom applied and almost always for a short period. In the regions of severe climate, seasonal freezing and long-term preservation of low temperatures in a mass of frozen ground can compete in effectiveness and economy with the traditional methods of loose ground stabilization, quicksand and boggy—clayey deposits, in particular. In practice, different methods and systems are applied for freezing the ground using the cold atmosphere air as a heat-absorbing medium. Systems with forced pumping of the intermediate heat carrier or of the air itself are more economic than machine freezing, but they are unreliable and maintenance is very expensive. Freezing devices using natural circulation of a single-phase and double-phase heat carrier in hermetically sealed cavities or thermosiphons permit effective control of the temperature regime of the ground in the seasonal and annual cycles of temperature variation of the ground and atmosphere air with the minimum operating expense. The paper considers the operational features of freezing systems and different devices, and gives examples of the utilization of artificially frozen ground in hydraulic structures and in foundations of industrial buildings and dwelling houses. The possibility of creating artificially frozen masses used as foundations of the structures built in severe climatic regions is considered, and examples of the existing buildings constructed on the artificial lenses of frozen ground are given.

The long and successful experience of the Dutch in recovering land from the sea and protecting it from inundation needs no emphasis. Even their ingenuity in civil engineering has been challenged, however, in the design and construction of a storm-surge barrier across the Eastern Scheldt, for it has virtually to be built on quicksand. This article describes the way in which the problem has been solved by laying huge prefabricated filter mattresses on the seabed to provide a secure foundation against the assaults of the highest tides.

Scouring is generally a phenomenon that takes place by running water on the movable bed. The external force in this case is given both as the shearing force and the normal force, therefore, various kinds of scouring arise from the combination of these two sorts of force.For the analytical research of the scouring phenomenon, we are required to reveal the happenings when each of these forces works independently.Actually, the scour resulting from the action of the simple shearing stress has hitherto been treated as a problem of critical tractive force. In this case, on the assumption that the drag coefficient of sand grains is similar to that of falling grains in the water at rest, the author derived an experimental formula for the critical tractive force from the published experimental data and the author's own data, but range of application of the analytical research of scour on a particular locality is wider when considering the critical bed velocity along the movable bed rather than when the critical tractive force is considered.According to the above considerations, the author discussed the drag coefficient for rest state of movable bed on the basis of our experimental data, deriving the critical bed velocity formula from considerations of both the tractive force and drag coefficient. The author nominated the scouring phenomenon in this case “scouring mechanics of the first kind”, and these problemes have been alloted for chapter I.If the normal force or pressure changes along the movable bed, seepage force is exerted on the sand grains bringing about scour as in the case of quicksand and piping. On the assumption that permeable layer is uniform, the author discussed the piping phenomenon, and proposed a new creep theory which is proved by his own experiments.The phenomenon of scour due to such seepage water is styled “scouring mechanics of the second kind”, and the piping problem has been alloted for chapter II.The most natural scouring phenomenon takes place when two forces act along the movable bed at the same time, the phenomenon of scour in this case is styled “scouring mechanics of the third kind”.Analytical research of several problems in this case can be performed by replacing the movable bed with the fixed bed, investigating the two external forces, and then assuming the scouring phenomenon. Dealing with the scour from jet, as an example, the writer put it in chapter III.From the above considerations, the phenomenon of scour is analyzed and systematized in this paper, giving us expectation to find a rational method of engineering work for the effective prevention of scouring.

1. In many cases, the conservation of a thick layer of permafrost soils in the foundations of dams is technically justified. Observations on dams during thawing and consolidation of their foundations permit evaluating the possibility of constructing thawed dams on collapsible permafrost soils. 2. A developed horizontal drain embedded in the foundation, in the immediate vicinity of the core, ensures piping stability of dam foundations consisting of finely dispersed soils occurring partially in the permaforst condition. 3. Under similar geologic conditions, in order to remove the pore pressures and to accelerate consolidation of the foundation, the most rational solution is the use of dams with compact cores and pervious supporting masses. 4. Techniques were developed for removing weak saturated soils of a quicksand nature by means of excavators and supported by using wood-metal plankings placed on 1.0-m thick gravel-pebble layers. The most suitable time for excavation of these soils was during the winter period. 5. The replancement, during preparation of the core foundation, of the covering layer of gravel-pebble material by a fill which was subsequently heated by an electric current and compacted, permitted reducing the construction period. This method can be recommended as an alternative for similar conditions.