Sand Chamber Research Articles

Automatic air pluvation system for physical modelling applications

This paper presents an air pluviation system, developed to facilitate 1g physical model tests in granular soils. The deposition process is fully automated and requires minimal input from the operator, thereby significantly reducing the time required to deposit large volumes of granular material, improving the uniformity of the prepared specimens and the reliability of test results. The components comprising the pluviation system have been calibrated to produce loose-to-very dense sand beds, of relative density that ranges between Dr = 7% and > 100% of the maximum density achieved with the procedures described in the pertinent standards. The testing chamber where sand is deposited is instrumented with an array of pressure sensors, and the rig is equipped with a miniature cone penetration testing (mini-CPT) device. Measurements from the earth pressure sensors and cone tip resistance profiles are used to evaluate how friction at the sand–chamber interfaces affects the distribution of geostatic stresses inside the chamber, the uniformity of sand beds and boundary effects during deposition and during mini-CPT testing. The air pluviation system allows preparing layered sand profiles by adjusting the deposition parameters on the fly, and this feature is demonstrated through the analysis of mini-CPT tests performed in layered sand beds.

Study on the Solution of Sand Slabbing in the Tailing Sand Bin of Huanggang Iron Ore Mine

In order to improve the tailings utilization rate and realize full tailings’ filling in Huanggang iron mine in Inner Mongolia, a flocculation settlement system was added, which resulted in silting and consolidation of tailings in sand silts. Based on this, the reason for the deposition and caking of tailings was obtained through analysis, and a set of coarse and fine tailings bin filling system was proposed. The tailings of the plant were pumped to the filling station by slurry pump. Firstly, the tailings with large particle size difference were divided into coarse tailings and fine tailings by hydrocyclone so that the fine tailings entered the No. 1 sand bin and the coarse tailings entered the No. 2 sand bin. Then, flocculant was added by automatic flocculant dosing device to flocculate and settle the coarse and fine tailings, and then, it was mixed, stirred, and filled into the well. The results showed the following. (1) The particle size difference of tailings in Huanggang Iron mine increased and resulted in unstable flocs. The coarse tailings settled to the bottom of the silo before the fine tailings, and the compression time was too long, leading to the phenomenon of silting and consolidation. (2) Flocculation and settlement of coarse and fine tailings in different sand silos can avoid deposition and compaction of tailings in sand silos. (3) According to the different requirements of the concentration and ratio of the filling slurry, the proportion of coarse sand and fine sand in the filling slurry can be controlled by controlling the flow size of the coarse sand and fine sand chamber, to achieve the design of reasonable particle size composition and concentration requirements. The research results are expected to provide technical support and theoretical guidance for the construction of full tailings cemented filling system in Huanggang iron mine.

Phylogenomics reveals accelerated late Cretaceous diversification of bee flies (Diptera: Bombyliidae).

Bombyliidae is a very species-rich and widespread family of parasitoid flies with more than 250 genera classified into 17 extant subfamilies. However, little is known about their evolutionary history or how their present-day diversity was shaped. Transcriptomes of 15 species and anchored hybrid enrichment (AHE) sequence captures of 86 species, representing 94 bee fly species and 14 subfamilies, were used to reconstruct the phylogeny of Bombyliidae. We integrated data from transcriptomes across each of the main lineages in our AHE tree to build a data set with more genes (550 loci versus 216 loci) and higher support levels. Our overall results show strong congruence with the current classification of the family, with 11 out of 14 included subfamilies recovered as monophyletic. Heterotropinae and Mythicomyiinae are successive sister groups to the remainder of the family. We examined the evolution of key morphological characters through our phylogenetic hypotheses and show that neither the "sand chamber subfamilies" nor the "Tomophthalmae" are monophyletic in our phylogenomic analyses. Based on our results, we reinstate two tribes at the subfamily level (Phthiriinae stat. rev. and Ecliminae stat. rev.) and we include the genus Sericosoma Macquart (previously incertae sedis) in the subfamily Oniromyiinae, bringing the total number of bee fly subfamilies to 19. Our dating analyses indicate a Jurassic origin of the family (165-194Ma), with the sand chamber evolving early in bee fly evolution, in the late Jurassic or mid-Cretaceous (100-165Ma). We hypothesize that the angiosperm radiation and the hothouse climate established during the late Cretaceous accelerated the diversification of bee flies, by providing an expanded range of resources for the parasitoid larvae and nectarivorous adults.

Shaking Water Out of Sands: An Experimental Study

AbstractStrong earthquakes can cause different kinds of hydrological responses, and several mechanisms have been suggested to explain them. Verification of these mechanisms, however, is often lacking. Here we test some hypotheses with a laboratory experiment, in particular the hypothesis that dynamic strain mobilizes trapped water in the unsaturated zone. We construct a sand chamber, partially saturated with water, and subject it to “seismic” shaking of controlled energy. Pore pressure in the saturated and unsaturated zones is monitored before and after shaking. We identify three distinct mechanisms: consolidation of sediments in the saturated zone, release of capillary water from the capillary fringe, and mobilization of isolated pore water in the unsaturated zone. Each mechanism may cause pore pressure in the saturated zone to suddenly increase with shaking, and each may offer new insights to understand the source of the extra water and other shallow hydrological responses that appear after earthquakes.

Potential new evidences of bee fly parasitoidism on ground-dwelling insects in mid–Cretaceous Burmese amber (Diptera: Bombyliidae)

Two new ‘Tomophthalmae’ bee flies Paleocytherea pouilloni gen. et sp. nov., and Nidergasia neraudeaui gen. et sp. nov. are described from the mid–Cretaceous Burmese amber. They are provisionally not attributed to a precise subfamily. The female of Paleocytherea pouilloni has terminalia modified into a very wide chamber with acanthophorite spines on tergites 9 + 10 and a row of ventral setae evocating a specialized hair brush. These structures allowed digging into sand to lay eggs, and possibly would characterize a sand chamber similar to those of several extant Bombyliidae that use it to coat eggs with sand and attack ground-dwelling insects. Eggs are wrapped with sand, avoiding dessication and/or direct competition with more efficient parasitoids, including wasps. This discovery suggests a potential great antiquity for this behavior (e.g., potential competitors like angarosphecid wasps are recorded in Burmese amber). Potential bee fly hosts were antlions, pygmy mole crickets, and the earliest bees, also known in the Burmese amber.

The effect of infiltration flux on air counterflow in a 2-D confined sand chamber

Experiments were carried out to investigate the effect of infiltration flux on air counterflow in a 2-dimensional (2-D) confined sand chamber. The air saturation distribution was monitored using light transmission and the air pressure was measured by manometers. As infiltration flux increased to 1000 mL/min and 1100 mL/min, significant increase in air pressure was observed. Due to the increase of air pressure, water infiltration was retarded, leading to a significant decrease in air outflow rate at high infiltration flux. When the infiltration flux was larger than 800 mL/min, the air flowed out of the sand chamber in the form of air “fingers”. The underlying process of the finger-like air outflow pattern was analyzed quantitatively, and the critical infiltration flux leading to air “fingers” was estimated based on the relative air/water permeability of the working sand. The Green-Ampt model showed that the infiltration process was retarded by air counterflow when the air pressure head was comparable to the depth of the wetting front at high infiltration flux.

Phylogeny and taxonomic revision of the genus Eristalopsis Evenhuis (Diptera: Bombyliidae: Bombyliinae)

The endemic Australian bee fly genus Eristalopsis Evenhuis, 1985 (Bombyliidae: Bombyliinae) is reviewed including 11 new species: E. aurata sp.n., E. concava sp.n., E. danielsorum sp.n., E. flava sp.n., E. maculata sp.n., E. minor sp.n., E. parva sp.n., E. rubra sp.n., E. smarti sp.n., E. uniformis sp.n., E. wrightae sp.n. In addition, we generate a morphological phylogeny including all recognised species. This genus can easily be distinguished from other Australian genera in the subfamily Bombyliinae by having a 2-segmented antennal flagellum, cell br longer than cell bm, crossvein m-m in apical half of cell dm, crossvein r-m much longer than crossvein m-m, abdominal tergites with black and yellow pattern, and female genitalia without sand chamber. A key to species of Eristalopsis is provided.

The effect of infiltration flux on air counterflow and entrapment in a 2-D sand chamber

The effect of infiltration flux on air counterflow and entrapment in a 2-D sand chamber

Experimental study of the moisture distribution on the wetting front during drainage and imbibition in a 2D sand chamber

In the present study, the moisture distribution on the wetting front during drainage and imbibition in a 2D sand chamber is studied thoroughly. Based on the high-resolution data measured by light transmission method, the moisture distribution is observed and then analyzed quantitatively. During drainage and imbibition, different moisture distributions are observed: (a) during drainage, moisture contents fluctuate in a larger range and fingers can be seen on the wetting front; (b) while during imbibition, moisture contents fluctuate in a smaller range and the wetting front is more regular. The Hurst coefficients are successful in capturing different characteristics of the moisture distribution between drainage and imbibition. During imbibition, the Hurst coefficients are around 0.2 on the wetting front; while during drainage, the Hurst coefficients are around 0.5. As the porosity changes from 0.336 to 0.383, the moisture distribution in the sand chamber does not display obvious change. While as the imbibition rate increases from 5 ml/min to 400 ml/min, the moisture distribution on the wetting front becomes more uniform.

Novel carbon fiber cathode membrane with Fe/Mn/C/F/O elements in bio-electrochemical system (BES) to enhance wastewater treatment

A novel conductive membrane with Fe/Mn/C/F/O elements is developed, it functions as the catalytic cathode of MFC and the antifouling filter of MBR simultaneously, in a newly designed integrated wastewater treatment system, without proton exchange membrane (PEM). The optimal conductive membrane is characterized using SEM-EDX, XRD and XPS. BET and porous structure analysis of the grounded membrane material indicate a narrow and small pore size (2–7 nm). The membrane surface is rich in Fe species (Fe - Fe2O3- Fe3O4) and manganese oxide (MnO2). Its characteristics such as excellent electro-chemical oxygen reduction reaction (ORR) activity, high clear water flux (>240 L/(m2·h)) and better antifouling filtration performance are further confirmed. The new system features bio-electrochemical system (BES) and integrates bio-filtration (trickling filter and air contact oxidation bed) and proton transfer through quartz sand chamber (QSC) which eliminates the use of expensive proton exchange membrane. The system removes chemical oxygen demand (>97.4%), ammonia nitrogen (>96.7%), total phosphorus (>98.0%) effectively, and it simultaneously generates electricity (446 mW/m3). The low cost and high performances, economic and advantageous system has good compatibility with existing wastewater treatment facilities and a wide application prospect.

Development of a novel carbon-based conductive membrane with in-situ formed MnO2 catalyst for wastewater treatment in bio-electrochemical system (BES)

A new carbon-based RGO/PVDF/MnO2 conductive membrane was developed to treat high load wastewater and recovery energy through bio-electrochemical system (BES), combining Membrane bioreactor (MBR) and Microbial fuel cell (MFC). The conductive membrane dual functions as the cathode of MFC and the filtration medium of MBR simultaneously. The structures of the conductive membrane were investigated by SEM, EDX and XPS, the existence of manganese dioxide catalyst, the high porosity and smooth surface morphology were confirmed. During operation, the membrane always maintained distinct ORR and electrochemical activity, exhibited excellent anti-fouling and flux recovery property, also better COD removal property than the control membrane without MnO2. Replacing proton exchange membrane (PEM) using Quartz sand chamber (QSC), the BES power density was 228mW/m3 higher than using PEM. The internal resistance, calculated in accordance with the power density curve using QSC was lower than that of the control group (respectively 752Ω and 937Ω). The results confirmed that it was feasible to replace the expensive PEM with cheap materials. The novel carbon-based conductive membrane with in-situ formed MnO2 catalyst and constructed BES with QSC were promising and beneficial for the future scale-up of BES.

Development of a novel proton exchange membrane-free integrated MFC system with electric membrane bioreactor and air contact oxidation bed for efficient and energy-saving wastewater treatment

A novel combined system integrating MFC and electric membrane bioreactor (EMBR) was developed, in which a quartz sand chamber (QSC) was used, replacing expensive proton exchange membrane (PEM). An air contact oxidation bed (ACOB) and embedded trickling filter (TF) with filled volcano rock, was designed to increase dissolved oxygen (DO) in cathodic EMBR to save aeration cost. Membrane fouling in EMBR was successful inhibited/reduced by the generated bioelectricity of the system. The combined system demonstrated superior effluent quality in removing chemical oxygen demand (>97%) and ammonia nitrogen (>93%) during the stable operation, and the phosphorus removal was about 50%. Dominant bacteria (Nitrosomonas sp.; Comamonas sp.; Candidatus Kuenenia) played important roles in the removal of organic matter and ammonia nitrogen. The system has good application prospects in the efficient use of water and the development of sustainable wastewater recycling technology.

Revision of the Australian bee fly genus Eusurbus (Bombyliidae, Bombyliinae), and description of Zentamyia gen. nov.

We review the endemic Australian bee fly genusEusurbusRoberts (Bombyliidae, Bombyliinae) and recognize two described species and three new species. The monotypic genusBromoglycisHull is identified as a new junior synonym ofEusurbus. Another species,E. nigracinctusRoberts, is designated as the type species of a new genusZentamyiagen. nov. This new genus is similar toEusurbusbased on several combined external characters including two-segmented palp, one-segmented flagellomere, open anal cell and cellr5, and the cellbrmuch longer than cellbm. However,Zentamyiagen. nov. has a more flattened scutum, and the apex of the flagellum is tapered. Moreover, the male genitalia are very different fromEusurbus, the male epandrium is narrow and long, and its posterolateral margin has a cluster of dense hairs; the female lacks a sand chamber, and the sperm pump is long and strong. A morphological phylogeny toEusurbusspecies is provided.

액체질소를 이용한 강관압입공법의 역학적 수리학적 안정화공법

본 연구에서는 강관압입 공법 적용 시 굴착 선단부에서 수리학적 또는 역학적 불안정으로 인해 발생 가능한 붕괴를 방지하는 목적으로 액체질소를 주입하여 굴착선단부를 안정화하는 공법에 관하여 연구하였다. 강관압입 공법 적용 시 오거 내 중공(中空)에 액체질소 주입관(호스)를 넣어 오거 선단부에 액체질소를 분사하는 방식을 고안하였다. 실내 실험을 위해 직경이 1,000 mm인 강관압입관을 기준으로 1/5축소 모형오거 및 토조를 제작하였다. 화강풍화토로 지반을 조성하여 함수비를 변화시켜가며 액체질소를 주입한 결과 오거 선단부에 동결 구근이 형성되어 강관압입공법 시공 시 발생 가능한 붕괴를 막을 수 있는 것으로 확인되었다. 액체질소를 이용한 동결공법은 지반이 모래일 때 보다는 소성이 있는 화강풍화토일 경우 더 효과적이었으며, 화강풍화토 지반의 경우 함수비가 최적함수비 이상일 경우 동결효율이 증가하는 것을 확인하였다. 액체질소 분사시간이 길어질수록 동결범위가 더 커졌으며 인위적으로 함수비를 급격히 증가시켜 수리학적 불안정을 유발해 보았더니 강관과 오거 전면의 지반이 약 120~300초 이내에 동결 되어 관으로 흙이 유입되지 않았으며, 차수효과가 있는 것으로 분석되었다. 이번 연구에서는 강관압입공법 안정화에 미치는 주요 인자에 대하여 액체질소를 이용하여 강관압입공법 시공 시 역학적 수리학적인 불안정이 발생할 경우, 화강풍화토 지반의 경우 붕괴를 막을 수 있는 효율적인 방법이 될 수 있다는 것을 확인하는데 큰 의의를 둔다. In this study, to prevent possible collapse caused by hydraulic or mechanical instability, liquid nitrogen injection method is developed and implemented at the tip of drilling auger of steel pipe propulsion tunneling. In this study, 1/5-scale model auger and sand chamber were manufactured. The prototype diameter of steel pile (or casing) is assumed about 1,000 mm. For the frictional sandy soils and plastic weathered soils, liquid nitrogen injection methods were tested varying water contents of the soils. For the induced hydraulic instability, the ground near the drilling auger was frozen within approximately 5 minutes preventing mechanical collapse and water infiltration. Securing stability of steel pile propulsion tunneling using liquid nitrogen was much more effective for which the water content of the soil somewhat exceeds the optimum water content.

Probabilistic electrical resistivity tomography of a CO2 sequestration analog

article Electrical resistivity tomography (ERT) is a well-established method for geophysical characterization and has shown potential for monitoring geologic CO2 sequestration, due to its sensitivity to electrical resistivity contrasts generated by liquid/gas saturation variability. In contrast to deterministic inversion approaches, probabilistic in- version provides the full posterior probability density function of the saturation field and accounts for the uncer- tainties inherent in the petrophysical parameters relating the resistivity to saturation. In this study, the data are from benchtop ERT experiments conducted during gas injection into a quasi-2D brine-saturated sand chamber with a packingthatmimicsa simpleanticlinal geologicalreservoir. The saturation fields are estimated by Markov chain Monte Carlo inversion of the measured data and compared to independent saturation measurements from light transmission through the chamber. Different model parameterizations are evaluated in terms of the recov- ered saturation and petrophysical parameter values. The saturation field is parameterized (1) in Cartesian coor- dinates, (2) by means of its discrete cosine transform coefficients, and (3) by fixed saturation values in structural elementswhoseshapeandlocationisassumedknownorrepresentedbyanarbitrary GaussianBellstructure.Re- sultsshowthattheestimatedsaturation fieldsare inoverallagreementwith saturationsmeasuredbylighttrans- mission, but differ strongly in terms of parameter estimates, parameter uncertainties and computational intensity. Discretization inthe frequency domain(as inthe discrete cosinetransform parameterization) provides more accurate models at a lower computational cost compared to spatially discretized (Cartesian) models. A priori knowledge about the expected geologic structures allows for non-discretized model descriptions with markedly reduced degrees of freedom. Constraining the solutions to the known injected gas volume improved estimates of saturation and parameter values of the petrophysical relationship.

Overcoming the effects of rogue taxa: Evolutionary relationships of the bee flies.

Bombyliidae (5000 sp.), or bee flies, are a lower brachyceran family of flower-visiting flies that, as larvae, act as parasitoids of other insects. The evolutionary relationships are known from a morphological analysis that yielded minimal support for higher-level groupings. We use the protein-coding gene CAD and 28S rDNA to determine phylogeny and to test the monophyly of existing subfamilies, the divisions Tomophtalmae, and ‘the sand chamber subfamilies’. Additionally, we demonstrate that consensus networks can be used to identify rogue taxa in a Bayesian framework. Pruning rogue taxa post-analysis from the final tree distribution results in increased posterior probabilities. We find 8 subfamilies to be monophyletic and the subfamilies Heterotropinae and Mythicomyiinae to be the earliest diverging lineages. The large subfamily Bombyliinae is found to be polyphyletic and our data does not provide evidence for the monophyly of Tomophthalmae or the ‘sand chamber subfamilies’.

Toxicity and Inhibition of Feeding and Tunneling Response of Naphthalene and 10 Derivatives on the Formosan Subterranean Termite (Isoptera: Rhinotermitidae)

In laboratory choice tests with either filter paper treatment or sand treatment, naphthalene and 10 derivatives were evaluated for their effects on the behavior of the Formosan subterranean termite, Coptotermes formosanus Shiraki (Isoptera: Rhinotermitidae). After 24-h exposure, workers avoided 50-microg/cm2-treated filter paper with 1'- and 2'-acetonaphthone. By day 8, feeding activity on filter paper treated with 1- and 2-methoxynaphthalene, 1'- and 2'-acetonaphthone were significantly reduced compared with the controls. Naphthalene and six other derivatives were not effective at 50-microg/cm2-treated filter paper. After 12-d exposure, tunnels constructed in sand treated with 1- and 2-methoxynaphthalene (0-3 cm2), 1'- and 2'-acetonaphthone (2-9 cm2), 2-naphthalene methanol (14-19 cm2), or 2-isopropylnaphthalene (16-19 cm2) at the rate of 100 mg/kg sand were significantly less than the controls (34 cm2). Consumption on filter paper placed on sand treated with 1- and 2-methoxynaphthalene and 1'- and 2'-acetonaphthone was significantly reduced (0-7 mg) compared with the controls (33-54 mg). 1-Methoxynaphthalene was the only treatment that caused significantly less feeding activity in the untreated sand chamber (0-6 mg) compared with the control (63-128 mg).

Seismic interferometry, intrinsic losses and Q‐estimation*

ABSTRACTSeismic interferometry is the process of generating new seismic traces from the cross‐correlation, convolution or deconvolution of existing traces. One of the starting assumptions for deriving the representations for seismic interferometry by cross‐correlation is that there is no intrinsic loss in the medium where the recordings are performed. In practice, this condition is not always met. Here, we investigate the effect of intrinsic losses in the medium on the results retrieved from seismic interferometry by cross‐correlation. First, we show results from a laboratory experiment in a homogeneous sand chamber with strong losses. Then, using numerical modelling results, we show that in the case of a lossy medium ghost reflections will appear in the cross‐correlation result when internal multiple scattering occurs. We also show that if a loss compensation is applied to the traces to be correlated, these ghosts in the retrieved result can be weakened, can disappear, or can reverse their polarity. This compensation process can be used to estimate the quality factor in the medium.

Apiformyia, a new genus of Australian bee flies (Diptera: Bombyliidae, Bombyliinae) with affinities to the New World Heterostylum Macquart

Apiformyia gen. nov. (Diptera: Bombyliidae) is described based on a large series of specimens from the Northern Territory of Australia. The specimens represent a single new species A. australis sp. nov. The genus belongs to the Bombyliinae, and has remarkable anatomical affinities to the New World genus Heterostylum Macquart. In particular, the head of Apiformyia has a sinuous posterior eye margin, but lacks a line bisecting the facets as found in most Anthracinae that also share such an eye margin. A sinuous posterior eye margin is uncommon in the subfamily Bombyliinae, being only found in Heterostylum and four other genera found in the New World, Afrotropical and Palaearctic regions. Additionally, Apiformyia shares with Heterostylum alone an unusual wing venation, with cell R 5 closed, and the apex of cell dm-cu meeting the fork of M 1 and M 2 , there being no stem of M 1+2 . The male genitalia of Apiformyia are generalized bombyliine in form, and do not share the particular unique features of Heterostylum such as the large recurved epiphallus and the gonostylus with apical beak-like process. The female genitalia of Apiformyia lack the sand chamber, acanthophorite spines and presents spermathecae with elongated bulbs, spermathecal ducts more than twice as long as sperm pump and sclerotized collars well developed, also differentiating the genus from Heterostylum.

WITSEG sampler: a segmented sand sampler for wind tunnel test

The flux profile of blowing sand is the reflection of a large number of sand particles moving in different trajectories. To describe the function of the flux profile requires measuring the flux of blown sand at different heights. A segmented sand sampler for wind tunnel study (WITSEG sampler) has been designed and evaluated in a wind tunnel. The sampler is 0.6 m high and sectioned into 60 openings that can measure the flux profile of blowing sand at 10-mm intervals. Special attention was paid in designing the sampler to its practicability and efficiency. For the convenience of use, the leading edge with inlets, sand chambers and side cover are removable. To maximize the sampling efficiency, the leading edge is wedge-shaped so that the width of the inlets is 5 mm, while the width of the sand chamber is 15 mm. Each sand chamber has two screened vents that are connected to a vertical vent to minimize the air pressure inside the sand chamber and maximize its efficiency. Wind tunnel evaluation shows that the sampler is good for measuring aeolian sand flux. Both the measured flux profile and total flux show a reasonably good agreement with the widely accepted flux profile function and sand transport equation. It has an overall efficiency of 0.91. The WITSEG sampler that can measure the detailed variation of blown sand flux with height proves to be a good tool for studying the flux profile of blowing sand.