Small Partition Research Articles

New insight into the mechanism of biofouling-resistant thiazole-linked covalent organic frameworks for selective uranium capture from seawater

The extraction of uranium from seawater is crucial for the sustainable production of nuclear fuel. Traditional amidoxime-functionalized adsorbents suffer from competitive adsorption of vanadium ion and biofouling. These challenges motivate the development of novel adsorbents for selective uranium extraction from seawater. Herein, four kinds of thiazole-linked covalent organic frameworks (COFs) were investigated to harvest uranium from seawater. The selectivity and anti-biofouling performance were systematically investigated through the molecular dynamics (MD) simulations. Driven by the pore size sieving effect and electrostatic interaction, the Ca2UO2(CO3)3 complex and vanadate anions were selectively separated by different COFs in special areas. On one hand, benefits from the small steric partition factor, the Ca2UO2(CO3)3 complex can stick on the surface of COFs. On the other hand, the dispersive negatively and positively charged areas of studied COFs work as potential binding sites for the Ca2UO2(CO3)3 complex and vanadate anions, respectively. Moreover, an analysis of pulling force and desorption time between uranium and vanadium ions further confirmed the selectivity of various thiazole-linked COFs. The anti-biofouling property was comparatively investigated by dynamic trajectory and solvent accessible surface area. Our outcomes illustrate that the hydroxyl and zwitterionic groups in the thiazole-linked COFs endow their strong surface hydrations to resist marine biofouling. In particular, the TpBdsaPa is identified as a promising candidate due to charge dispersed zwitterionic group as well as remarkable anti-biofouling ability. The present study sheds an atomic-level understanding of the thiazole-linked COFs for selective uranium uptaking from seawater, which will provide aid to design novel adsorbent with highly selective uranium extraction capacity and strong anti-biofouling property.

Eye-Tracking Analysis of Proposed Signage Design to Prevent Accidents Caused by the Abrupt Appearance of Dividers on Indian Roads

The road transport system is expanding considerably in developing countries. Villages are connecting to major cities for business, education, health, and many other reasons because of road development and smooth transportation. There has been a rise in the number of road accidents observed, caused by abruptly appearing dividers on roads and a lack of required signage systems. This paper discusses scenarios of accidents due to such abruptly appearing dividers and offers a strategy to design appropriate signage to avoid road accidents in the future. It has been observed that permanent or movable arbitrary fixtures, such as a barricade or a small partition block wall, are installed to separate lanes, in addition to white-colored stripes that are typically employed for lane separation on roads. These fixtures, although they are intended as lane-dividing solutions on roads, cause serious, and at times, fatal accidents, due their sudden, uninitiated appearance on the road. To address this problem, alternative signage designs were designed and tested on Indian roads, based on human cognitive responses and visual attention analysis on signage using an eye-tracking method. In addition, the semantic quality and legibility of alternate signage designs were evaluated using a questionnaire to judge their overall efficacy. Hence, the best signage design solution is proposed for implementation near or before occurrences of road dividers to avoid accidents.

Feasibility of Breast Cancer Detection Through a Convolutional Neural Network in Mammographs

In the Iraq female samples, the malignant neoplasm type with the highest mortality rate is breast cancer. When the disease is detected early, the success rate is higher, resulting in improved prognosis and, consequently, cure. The present study aims to analyse the viability of a system capable of detecting breast cancer through convolutional neural networks, classifying a mammogram into five classes: non-cancer; benign calcification; malignant calcification; benign mass; and evil mass. Processing was carried out on the database containing 55,890 images, in which the data was converted from records structure to image format, which is necessary when using the neural network. After this stage, the images were classified into the five categories mentioned to enable tests to be carried out to verify the accuracy of the machine learning algorithm in identifying and classifying breast cancer. Using a small partition of 10% of images from the total database to verify the initial results presented in this work, it was possible to obtain 44% of global accuracy, highlighting the ability to expedite the early and rapid detection of breast cancer using artificial intelligence.

Importance of clay-H2 interactions for large-scale underground hydrogen storage

Underground hydrogen storage is considered an option for large-scale green hydrogen storage. Among different geological storage types, depleted oil/gas fields and saline aquifers stand out. In these cases, hydrogen will be prevented from leaking back to the surface by a tight caprock seal. It is therefore essential to understand hydrogen interactions with shale-type caprocks. To this end, natural pure montmorillonite clay was exposed to hydrogen gas at different pressures (0–50 bar) and temperatures (77, 195, 303 K) to acquire data on its adsorption capacity related to UHS and caprock saturation. Montmorillonite was chosen because of its large specific surface area enabling quantification of the adsorption process. Hydrogen adsorption was successfully fitted with a Langmuir isotherm model and yielded small partition coefficients indicating that hydrogen does not preferentially adsorb to the clay surface. Adsorption on montmorillonite goes back to weak physisorption as inferred from minor negative changes in the enthalpy of reaction (−790 J/mol), derived from an Excel Solver approach to the van't Hoff equation. Based on own as well as literature values, adsorption capacities, which were originally reported as mol/kg or wt%, are recast as hydrogen volume adsorbed per specific surface area (μL/m2). The acquired range is surprisingly narrow, with values ranging from 3 to 6 μL/m2, and indicates the normalised volume of hydrogen that can be expected to remain in the shale-type caprock after injected hydrogen migrated upwards through the porous reservoir. This ‘residual’ caprock saturation with hydrogen can be further restrained by considering the geothermal gradient and its effect on the molar volume of hydrogen. The experimental results presented here recommend injecting hydrogen deeper rather than shallower as pressure and temperature work in favour of increased storage volumes and decreased hydrogen loss through clay adsorption in the caprock.

Heat flux enhancement by regular surface protrusion in partitioned thermal convection

We investigate the influence of the regular roughness of heated and cooled plates and adiabatic partition boards on the mean heat transport in a square Rayleigh–Bénard (RB) convection enclosure by two-dimensional direct numerical simulations. The roughness is in the form of isothermal protrusions with a rectangular base and triangular tip. The protrusion height varies from 10% to 25% of enclosure height. With increased protrusion height, the large-scale circulation cannot wash out the cavity between two consecutive protrusions. Thus, the overall heat transport of the enclosure impedes. We have inserted the partition boards between two successive protrusions with a gap between the conduction plate and the partition board to wash out the cavity. The partition board height varies from 20% to 99.8% of enclosure height. We have performed the simulations for the range of Rayleigh number 106–108 and at a fixed Prandtl number of 1. The tip of the triangular protrusion acts as an active plume-emitting spot. We observe a single large-scale elliptical roll with counter-rotating corner rolls for small partition board height. With an increase in partition board height, an elliptical large-scale roll breaks down into the number of large-scale rolls horizontally placed one beside the other. Finally, we observe multiple rolls stacked vertically when the partition boards almost touch the conduction walls. Heat flux enhancement strongly depends on large-scale flow structures. We found a maximum heat flux enhancement in protrusion with partitioned RB case approximately up to 4.7 times the classical square RB for an optimal gap between conduction plate and partition board. The maximum heat transport enhancement is due to the strong horizontal flow through the gap between the conduction plate and partition board, which locally reduces the thermal boundary layer's thickness. The interaction between the horizontal jets and the thermal boundary layers enhances heat transport.

Technological innovations in construction of underground caverns in basaltic rocks at Baihetan Hydropower Station on Jinsha River

The two underground powerhouses on the left and right banks of Baihetan Hydropower Station (BHT-HS) are symmetrically arranged inside basaltic rocks in the alpine gorge reach of the lower Jinsha River. Each of them is equipped with 8 sets of 1,000 MW hydraulic turbine generators, with the largest unit capacity, total installed capacity, span of main powerhouse (i.e. 34 m), diameter of dome-shaped tail-regulating chamber (max diameter of 48 m) and scale of underground caverns around the world. Due to complex layout, interaction between caverns and high hollowing rate, the construction process of the underground cavern group is faced many challenges. For example, the cavern excavation is located in the high ground stress area dominated by horizontal tectonic stress; the underlying basalt fractures are well developed, and the rock is hard and brittle, with low crack initiation strength; columnar jointed basalts develop locally; a number of large and weak gently-sloped shear zones develop diagonally cutting the main powerhouse. Following the construction ideology of “understanding, utilization, protection, monitoring, and feedback analysis on the surrounding rock masses during the construction period”, and with the engineering construction procedure of “the excavation, analysis, prediction and inspection of each rock layer”, this paper proposes a set of innovation construction technologies including “advanced pre-control, thin vertical layer, small planar partition, short excavation progress, fine blasting, strong and quick support, short interval monitoring, quick feedback, precise dynamic optimization” to control the internal cracking of the hard and brittle basaltic rocks, discontinuous deformation of staggered zones and spatio-temporal deformation of underground caverns in high geostress. It has promoted the safe and orderly construction of BHT-HS, the technical progress of the construction of hydropower station projects in China, and may also be applicable to the design and construction of similar projects worldwide.

Biochar-based fertilizer enhanced Cd immobilization and soil quality in soil-rice system

Cadmium (Cd) contamination poses a serious problem in paddy soils because of its high health risk through soil-food chain transfer. To evaluate the effect of biochar-based fertilizer on Cd uptake, soil and rice quality, biochar amendment at rates from 0 to 15 t/hm2 was conducted in Cd polluted paddy soils. For successive two rice seasons, biochar treatments greatly reduced rice Cd and soil bioavailable Cd content. Furthermore, the concentration of bioavailable Cd decreased accordingly with the increase of biochar content. When soil properties, such as pH and soil organic carbon (SOC) were significantly improved, grow indexes of rice, especially for the late rice, would be partly improved. Most of the bioavailable Cd was immobilized in root, only a small partition of Cd was transferred to brown rice. The main stage for Cd accumulation was from heading stage to harvest stage.

Advice on the rationalized layout of outpatient clinics in a wound repair department

According to a document issued by the General Office of National Health Commission, "one person, one diagnosis, and one room" is required in the process of outpatient consultation. However, the patient will need to go to another room for dressing change after the doctor checks the wound if sticking to the conventional layout of current wound repair specialist outpatient clinic in hospitals and following the regulation of "separation of diagnosis and treatment". To allow a patient walking back and forth with the exposed wounds to different clinics or going to another clinic for dressing change with the original dressing reapplied to the wound is against the regulation of nosocomial infection control and the principle of sterility. To ensure that the layout of the outpatient clinic in the wound repair outpatient department not only conforms to the principle of "one person, one diagnosis, and one room", but also meets the characteristics of the diagnosis and treatment process of chronic wounds, this paper proposes the layout of "large space and small partition" in the wound repair clinic.

Niche partitioning in small mammals: interspecific and biome-level analyses using stable isotopes

Abstract Small mammal assemblages from South America provide a unique opportunity to measure coexistence and niche partitioning between marsupials and placentals. We tested how these two major clades partition environmental resources by comparing stable isotopic ratios of similar sized Didelphidae and Sigmodontinae in four Brazilian biomes: Pampas grassland, Pantanal wetland, Cerrado woodland savanna, and Atlantic Forest. Generally, didelphid isotopic niche follows a scaling law, because we found an association between δ15N enrichment and body mass. Sigmodontines that primarily partition the environment via forest strata showed a greater intake of C4 or/and crassulacean acid metabolism (CAM) plants than didelphids, as reflected by their wider trophic niche. Values of δ13C were highest in savannas and grasslands (Cerrado and Pampas biomes), and values of δ15N were highest in the Atlantic Forest (in sigmodontines) and Pampas (in didelphids). While assessing patterns between the two major Brazilian biomes (Atlantic Forest and Cerrado), we found evidence of a broader trophic niche for both clades in the Cerrado. In the Atlantic Forest, niche occupation by Didelphidae was completely enclosed within the Sigmodontinae trophic niche. Both clades showed less overlap in the Cerrado, a less productive environment. Our results highlight the importance of a comparative framework and the use of stable isotopes for testing ecological questions related to how small mammalian communities partition their niche.

Estuary‐Level Genomic Variation Confirms Demographic and Life History Differences among Black Drum Populations in Texas

AbstractThe Black Drum Pogonias cromis is a year‐round resident in estuarine and nearshore habitats throughout the Gulf of Mexico and is common in Texas. Multiple studies have highlighted life history and demographic variation in this species among estuaries, and tagging studies conducted in Texas suggest limited migration between adjacent estuaries. While these findings raise the potential for genetic heterogeneity among estuaries via accumulation of genetic drift, such an effect has never been tested. We used 5,340 genomic single nucleotide polymorphisms from a reduced‐representation genomic library to assess the magnitude and geographic pattern of genetic heterogeneity in Black Drum sampled from multiple estuaries in Texas. We found significant genetic heterogeneity that could be partitioned into three regional groupings: northern (Sabine Lake to San Antonio Bay), central (upper Laguna Madre and its secondary bays) and southern (lower Laguna Madre). These regional groupings roughly coincide with significant differences in life history strategies noted in previous studies and suggest a regional stock structure that is anchored by two independently collected lines of evidence. There was also evidence for weak but significant genetic structure among adjacent secondary estuaries within the Baffin Bay complex. Finally, outliers from the genomic data set correlated weakly (but significantly) with differences in residual growth among individuals. These findings imply genetic heterogeneity of Black Drum among and within estuaries, correlation of growth phenotypes with a small partition of outlier loci, and correlation between genomic patterns and complex regional differences in life history phenotypes described previously. Stock assessments for this species should carefully consider regional stock definitions and model parameters because such inputs may vary significantly above and below the scale of estuaries.

Hierarchy recurrences in local relaxation

Inside a closed many-body system undergoing the unitary evolution, a small partition of the whole system exhibits a local relaxation. If the total degrees of freedom of the whole system is a large but finite number, such a local relaxation would come across a recurrence after a certain time, namely, the dynamics of the local system suddenly appear random after a well-ordered oscillatory decay process. It is found in this paper, for a collection of $N$ two-level systems (TLSs), the local relaxation of one TLS within has a hierarchy structure hiding in the randomness after such a recurrence: similar recurrences appear in a periodical way, and the later recurrence brings in stronger randomness than the previous one. Both analytical and numerical results that we obtained well explains such hierarchy recurrences: the population of the local TLS (as an open system) diffuses out and regathers back periodically due the finite-size effect of the bath [the remaining $(N-1)$ TLSs]. We also find that the total correlation entropy, which sums up the entropy of all the $N$ TLSs, approximately exhibit a monotonic increase; in contrast, the entropy of each single TLS increases and decreases from time to time, and the entropy of the whole $N$-body system keeps constant during the unitary evolution.

Multilevel Modeling of Health Inequalities at the Intersection of Multiple Social Identities in Canada

ABSTRACT Health inequities in Canada are pervasive. Intersectional theory and novel quantitative methods can be used to understand health inequities. Drawing on a sample of adults from the 2015 and 2016 Canadian Community Health Survey, this study uses multilevel analysis individual heterogeneity and discriminatory accuracy (MAIHDA) to examine the intersectional effect of race, sex, income and immigration status on perceived health and perceived mental health. Small variance partition coefficients of the final models suggest that most of the variance across social strata is explained by the main effects for the four variables. Intersectional interaction effects for each social strata are reported.

A scalable and low latency probe-based scheduler for data analytics frameworks

Today’s data analytics frameworks divide jobs into many parallel tasks such that each task operates on a small partition of data in order to execute jobs with low latency. Such frameworks often rely on probe-based distributed schedulers to tackle the challenge of reducing the associated overhead. Unfortunately, the existing solutions do not perform efficiently under workload fluctuations and heterogeneous job durations. This is due to a problem called Head-of-Line blocking, i.e., short tasks are enqueued at workers behind longer tasks. To overcome this problem, we propose Peacock (Khelghatdoust and Gramoli, 0000) [25] a new fully distributed probe-based scheduling method. Unlike the existing methods, Peacock introduces a novel probe rotation technique. Workers form a ring overlay network and rotate probes using elastic queues of workers. It is augmented by a novel starvation-free probe reordering algorithm executed by workers. We evaluate Peacock against two existing state-of-the-art probe based solutions through a trace driven simulation of up to 20,000 workers and a distributed experiment of 100 workers in Apache Spark under Google, Cloudera, and Yahoo! traces. The performance results indicate that Peacock outperforms the state-of-the-art in all cluster sizes and loads. Our distributed experiments confirm our simulation results.

Preliminary exploration of molybdenum isotope fractionation during coprecipitation of molybdate with abiotic and microbial calcite

Molybdenum isotopes in marine carbonates have been proposed to track the redox conditions of oceans through time. Large variations of Mo concentration and isotopic composition were observed in primary biogenic carbonates and shallow-water carbonate sediments from modern oceans. However, it remains unknown whether the abiotic calcium carbonate precipitation process fractionates Mo isotopes and affects Mo isotopic composition in marine carbonates. To better understand carbonate Mo isotope proxy, we conducted abiotic calcite coprecipitation experiment to determine Mo partition coefficient in calcite and Mo isotope fractionation during molybdate incorporation into calcite. We also investigated Mo isotopic compositions in microbial calcite induced by photosynthetic activity of cyanobacteria and diatoms in the surface water of Fayetteville Green Lake (FGL), New York, USA.Our calcite coprecipitation experiment, for the first time, determined the Mo partition coefficient Kd=MoCacalcite/MoO42−CO32−solution = 1.49 × 10−5 in calcite at pH ~8.3. We observed a relatively small Mo isotope fractionation of 0.15 ± 0.06‰ with light Mo isotopes preferentially incorporated into calcite. The Mo isotope fractionation observed in our experiment most likely results from equilibrium isotope fractionation among different Mo species and preferential incorporation of the isotopically light Mo(VI) species (MoO42−) into calcite. Microbial calcite formed in FGL fractionated Mo isotopes in the same direction as abiotic calcite coprecipitation experiment but with significantly larger isotope fractionations (0.82–2.45‰) and significantly higher Mo concentrations (0.04–0.28 ppm vs. the inferred 0.002 ppm Mo from our abiotic calcite coprecipitation experiment). Molybdenum isotopic composition decreased with Mn/Fe ratios from +1.56 to −0.07‰, suggesting that Fe and Mn oxides dominantly control Mo isotope fractionation in these microbial calcite samples. Additionally, isotopically light Mo associated with organic matter (e.g., live or dead microorganisms like cyanobacteria) might also contribute to the light Mo isotopic composition in microbial calcite.The relatively small Mo isotope fractionation (0.15 ± 0.06‰) and Mo partition coefficient (1.49 × 10−5) in our abiotic calcite coprecipitation experiment indicate that calcite precipitation process has negligible effects on Mo isotopic composition in primary biogenic calcite precipitates. In contrast, Mo associated with organic matter, detrital particles, and Fe and Mn oxides, and carbonate diagenesis strongly affect Mo isotopic compositions in calcium carbonate precipitates in nature. Caution should be taken when applying Mo isotopes in ancient carbonates rocks to track seawater redox conditions.

Quasi-Stationary Distributions for the Voter Model on Complete Bipartite Graphs

We consider the discrete-time voter model on complete bipartite graphs and study the quasi-stationary distribution (QSD) for the model as the size of one of the partitions tends to infinity while the other partition remains fixed. We show that the QSDs converge weakly to a nontrivial limit which features a consensus with the exception of a random number of dissenting vertices in the large partition. Moreover, we explicitly calculate the law of the number of dissenters and show that it follows the heavy-tailed Sibuya distribution with parameter depending on the size of the small partition. Our results rely on a discrete-time analogue of the well-known duality between the continuous-time voter model and coalescing random walks which we develop in the paper.

Hardware Memory Management for Future Mobile Hybrid Memory Systems

The current mobile applications have rapidly growing memory footprints, posing a great challenge for memory system design. Insufficient DRAM main memory will incur frequent data swaps between memory and storage, a process that hurts performance, consumes energy, and deteriorates the write endurance of typical flash storage devices. Alternately, a larger DRAM has higher leakage power and drains the battery faster. Furthermore, DRAM scaling trends make further growth of DRAM in the mobile space prohibitive due to cost. Emerging nonvolatile memory (NVM) has the potential to alleviate these issues due to its higher capacity per cost than DRAM and minimal static power. Recently, a wide spectrum of NVM technologies, including phase-change memories (PCMs), memristor, and 3-D XPoint has emerged. Despite the mentioned advantages, NVM has longer access latency compared to DRAM and NVM writes can incur higher latencies and wear costs. Therefore, the integration of these new memory technologies in the memory hierarchy requires a fundamental rearchitecting of traditional system designs. In this work, we propose a hardware-accelerated memory manager (HMMU) that addresses in a flat address space, with a small partition of the DRAM reserved for subpage block-level management. We design a set of data placement and data migration policies within this memory manager such that we may exploit the advantages of each memory technology. By augmenting the system with this HMMU, we reduce the overall memory latency while also reducing writes to the NVM. The experimental results show that our design achieves a 39% reduction in energy consumption with only a 12% performance degradation versus an all-DRAM baseline that is likely untenable in the future.

Optimization of air-water microchannel heat exchanger using response surface methodology

Multivariate optimization of the air-water heat exchanger with microchannel coil has been presented in this paper. The effects of four geometry parameters, i.e. fin pitch, microchannel flat tube transversal row pitch, number of small channels and partition wall thickness, on heat transfer rate per volume and mass, pressure drops on air and water side, heat transfer efficiency and rate of compactness have been examined using the Response Surface Methodology. Data set, composed of 27 different geometry models, has been prescribed using Box-Behnken design method. Experimentally validated, 3D mathematical model and numerical procedure have been used for numerical simulations. Fluid flow and heat transfer simulations have been performed using CFD solver FLUENT. Numerical results have been employed to calculate the objective function responses. Obtained contour plots of the objective functions have been shown for various setups. According to objective function results, nonlinear regression models (polynomial functions) have been derived and the Genetic Algorithm has been used to obtain optimal setup. The comparison of results has been given, followed by discussion and conclusions.

Methanol linear gradient counter-current chromatography for the separation of natural products: Sinopodophyllum hexandrum as samples

Counter-current chromatography (CCC) is a unique, liquid-liquid partition chromatography process. Both the mobile and stationary phases are liquids, so no solid support matrix is used. CCC has gained wide acceptance as a preparative technique in a variety of fields. Because the mobile and stationary phases are both liquids, gradient elution is difficult to perform with CCC. Phase equilibrium must be maintained, so any change in the composition of one phase may induce a compositional change in the other. In this work, a new linear gradient elution method was developed for CCC. Biphasic solvent systems containing heptane, ethyl acetate, methanol, and water (HepEMWat) in various ratios were prepared and used to optimize both isocratic and linear gradient CCC separation with methanol. We first separated a test mixture of four standard compounds with partition coefficients ranging from 0.8 to 7.8. The separation resembled a reversed-phase process, and elution was performed while progressively decreasing the polarity of the mobile phase. Target molecules with small partition coefficients eluted first in the lower phase of the optimized HepEMWat solvent system. Elution of constituents with large partition coefficients was quite slow under isocratic conditions. Separation time was significantly reduced when elution was performed with a linear gradient using methanol and the optimal HepEMWat system. Elution with a 3:7:4:6 (v/v/v/v) HepEMWat system took approximately 200 min. This included an 80-min isocratic step, followed by gradient elution with methanol from 0% to 30%. The optimized methanol linear gradient CCC method was then used to separate a complex mixture of natural products isolated from Sinopodophyllum hexandrum (Royle) Ying roots. Twelve compounds with a wide range of polarities were well-resolved in a single separation. We have developed a convenient and cost-effective strategy for the separation of complex mixtures. No tedious mobile phase preparation step is required. The volume of unused mobile phase is minimal, so little solvent is wasted. The method is an important advance for the separation of mixtures that contain many compounds with a large range of polarities and partition coefficients, which are common features of natural products.

Composition dependence of solid-liquid interfacial energy of Fe-Cr binary alloy from molecular dynamics simulations

Composition dependence of the solid-liquid interfacial energy for Fe-Cr binary alloy is closely investigated by the molecular dynamics simulation in conjunction with the capillary fluctuation method. The solid-liquid interfacial energy of Fe-Cr alloy doesn’t increase monotonically with increasing Cr composition but takes the minimum at approximately Fe-19.1at%Cr. Regarding the anisotropy effect, the interfacial energy of solid-liquid interface with (1 0 0) orientation is larger than those of (1 1 0) and (1 1 1) orientations at all compositions. Moreover, the effect of solute partition on the solid-liquid interfacial energy is discussed on the basis of a conceptual calculation using the solid-liquid biphasic system with various hypothetical compositions. The fluctuation of the interface becomes smooth at the solid-liquid interface with the small partition coefficient, which results in a large solid-liquid interfacial energy.

Efficient Removal Without Efficient Regularity

Obtaining an efficient bound for the triangle removal lemma is one of the most outstanding open problems of extremal combinatorics. Perhaps the main bottleneck for achieving this goal is that triangle-free graphs can be highly unstructured. For example, triangle-free graphs might have only regular partitions (in the sense of Szemeredi) of tower-type size. And indeed, essentially all the graph properties $$\mathcal{P}$$ for which removal lemmas with reasonable bounds were obtained, are such that every graph satisfying $$\mathcal{P}$$ has a small regular partition. So in some sense, a barrier for obtaining an efficient removal lemma for property $$\mathcal{P}$$ was not having an efficient regularity lemma for graphs satisfying $$\mathcal{P}$$ . In this paper we consider the property of being induced C4-free, which also suffers from the fact that a graph might satisfy this property but still have only regular partitions of tower-type size. By developing a new approach for this problem we manage to overcome this barrier and thus obtain a merely exponential bound for the induced C4 removal lemma. We thus obtain the first efficient removal lemma that does not rely on an efficient version of the regularity lemma. This is the first substantial progress on a problem raised by Alon in 2001, and more recently by Alon, Conlon and Fox.