Cut Method Research Articles

Towards accurate dose assessment for emergency industrial radiography source retrieval operations: A preliminary study of 4D Monte Carlo dose calculations

The exposure devices utilizing high-activity gamma radiation sources for industrial radiography frequently encounter issues such as stuck or disconnected sources, posing a substantial risk of radiation exposure to the workers executing emergency source retrieval operations, emphasizing the importance of accurate dose assessment. In the present study, the radiation dose to the main worker during the process of source retrieval was calculated and compared for five emergency source retrieval procedures to retrieve stuck or disconnected sources, using 4D Monte Carlo dose calculation and a mesh-type reference computational phantom. For a stuck source, the dose values of the two source retrieval procedures (i.e., repair and cut methods) were found to be relatively small, which indicates that the worker might select either method based on personal preference or situational convenience. Conversely, for a disconnected source, the dose values of the three source retrieval procedures (i.e., fishing, connect/push, and hot stick methods) were much larger and show significant differences. Notably, the fishing method was associated with the lowest dose, whereas the hot stick method resulted in significantly higher doses, differences being as large as ∼5 times. These results underscore the fishing method as a preferable option, particularly over the hot stick method.

Characterization of entropy measures with connection number based indices of boric acid hydrogen-bonded 2D lattice sheets

The cut method is a computational approach utilized to predict the fundamental activities of physicochemical properties of chemical networks, also called topological indices. The connection number is a new idea, that gives interesting and good results of the topological indices (TIs) and entropy measures (EMs) for structural representation of chemical compounds and networks. The physical density of chemical networks is characterized by these indices. In this paper, we determined the computational results for indices based on connection numbers for a two-dimensional lattice sheet of hydrogen-bonded boric acid. Boric acid, an inorganic compound, is not very harmful when applied to the skin or consumed. Finally, graphical and numerical comparisons of topological numbers including the number of borate hydrogen-bonded double lattice forms are also included in this study.

Quantitative Structure-Property Relationship (QSPR) Modeling of Central Nervous System (CNS) Drug Activity using Molecular Descriptors

Background: L-type amino acid transporter-1 is a drug that stimulates the func-tions of the brain’s central nervous system. Membrane transporters have evolved, leading to a distinct approach in L-type amino acid transporter-1 drug delivery. One of the trans-porters used for transporting drugs across biological membranes is the L-type amino acid transporter-1. It is widely discussed in the medicinal field. Objectives: Numerous investigations indicate a close connection between the properties of alkanes and the diversity of central nervous system drugs in the brain, specifically log P and molecular weight. One important study that analyzes structural properties is focused on topological descriptors. Recently, topological indices have found application in the de-velopment of quantitative structure-activity relationships. These indices are correlated with the physicochemical properties of BCNS-acting drugs and their biological activity. Methods: The study employs significant methods of calculating topological indices: the edge set partition method and the Djokovi´c-Winkler relation (cut method) are utilized to calculate the values of these descriptors. Results: The results of distance and degree-based topological descriptors have been de-rived. The strong correlation between topological descriptors and the physicochemical properties of BCNS-acting drugs has been studied. Conclusions: This article identifies important topological features for various CNS medi-cations, aiming to support researchers in understanding the properties of molecules and their biological activity. Furthermore, we demonstrate how strongly these behaviors cor-respond to the physicochemical properties of central nervous system drugs.

Development Of Mutant From Lemon Leaves By Using Gamma Radiation And Leaf Cut Method Under Glass House And Field Condition

An experiment was conducted at the Horticulture division of Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh during the period from March 2024 to September 2024 to develop mutants from lemon leaves by using gamma radiation and leaf cut method under glasshouse and field conditions to find out the appropriate combination of irradiation dose and suitable environment on success, survivability, and growth of lemon. The experiment was consisted of two factors such as Environmental condition: (i) glass house and field condition and (ii) Nine gamma radiation levels (0 GY, 60 GY,80Gy,100Gy, 120 GY,140 GY,160 GY,180 GY and 200 GY).Mature leaves were collected from BINA Lebu-1 mother plants.Collected leaves were exposed by different doses of gamma radiation separately with 60 GY, 80GY, 100 GY, 120 GY, 140 GY, 160 GY,180 GY, 200 GY, and also a control at BINA from 60Co gamma radiation sources. The experiment was laid out in RCBD with three replications. Total 18 treatment combinations of the environmental condition and radiation levels. Irradiated leaves of lemon were planted in the unit plots on 8 March 2023 in the afternoon with spacing of 15cmx15cm (row to row and leaf to leaf distance). Different environmental condition showed significantly influenced on almost all the mentioned parameters studied concerned with growth and growth contributing characteristics. The highest percentage of success and survivability was found in glass house condition and the lowest % success and %survivability was found in field condition.The glasshouse condition producedhigher number of roots(4.77), longer root length(9.24cm), diameter of shoot( 4.95mm), higher number of leaves per plant(50.66) and field condition produced lower number of roots(3.55), smallest longer root length(7.14cm), lower diameter of shoot(2.26mm), lower number of leaves(43.00) per plant compared to the field condition. The application of 120GY irradiation level produced the highest number of roots (8.50), longest root length (16.1cm),the highest diameter of shoot (5.65mm), andthe highest number of leaves per plant (70.00) as compared to control. The combined effect of environmental condition and gamma radiations was statistically significant on the success, survivability and growth.120GY irradiation level in glasshouse condition produced the maximum roots (7.00), the longest root length (17.5.cm), the largest diameter of shoot (4.80mm), highest canopy volume (0.12m3 ) and the maximum leaves per plant (73.00). Similarly, the lowest values were in respect of almost all the mentioned parameters were found at field condition with control treatment. Therefore, the overall results indicate that glasshouse condition with 120 GY might be an efficient and eligible practice for developing mutant from leaves

ANALISIS FAKTOR PENYEBAB TERJADINYA (CCO) PADA PROYEK PEMBANGUNAN TEMPAT KULINER DAN POS JAGA TAMAN KOTA DENPASAR

In implementing construction projects, problems are often faced, one of which is the occurrence of changes. This cannot be avoided on most projects due to the uniqueness of each project and limited time and costs in the planning process. For this reason, adjustments need to be made and this often results in changes in costs and changes in project implementation time. In turn, adjustments made must also be accommodated in administrative and contractual aspects in the form of a Contract Change Order (CCO). The aim of this research was to determine the factors that cause CCO, and to find out the factors that cause CCO that are most dominant in the implementation of construction projects for culinary establishments and park guard posts in the city of Denpasar. This research uses a quantitative descriptive method, where there are 41 factors that cause CCO. The data analysis method was carried out using the cut off point method. The results of the research show that there are 33 factors that cause CCO in the construction of culinary establishments and guard posts identified from the results of literature studies, interviews and questionnaires with 30 respondents, and the most dominant factors that cause CCO are found to be 11 factors out of 33 factors- The most dominant factor causing CCO. Of the 11 factors, the highest average value is in variable X41, namely changes in quality and material specifications of 3.87 and the lowest is in variable.

An energy stable high-order cut cell discontinuous Galerkin method with state redistribution for wave propagation

Cut meshes are a type of mesh that is formed by allowing embedded boundaries to “cut” a simple underlying mesh resulting in a hybrid mesh of cut and standard elements. While cut meshes can allow complex boundaries to be represented well regardless of the mesh resolution, their arbitrarily shaped and sized cut elements can present issues such as the small cell problem, where small cut elements can result in a severely restricted CFL condition. State redistribution, a technique developed by Berger and Giuliani in [1], can be used to address the small cell problem. In this work, we pair state redistribution with a high-order discontinuous Galerkin scheme that is L2 energy stable under arbitrary quadrature. We prove that state redistribution can be added to a provably L2 energy stable discontinuous Galerkin method on a cut mesh without damaging the scheme's L2 stability. We numerically verify the high order accuracy and stability of our scheme on two-dimensional wave propagation problems.

Development of genetically modified rust resistant wheat: A breakthrough by dinted introgression of novel DREB2C and HSFA2 genes under stress induced expression

Wheat is a major staple food worldwide yet numerous yield limiting agents affect its productivity. Stripe rust is a major culprit in this context and efforts have been made to culminate this pathogen using conventional as well as advanced innovative techniques. Transgenic technology is of significant importance in this context and numerous success stories are evident to prove its worth. In the current study, two novel genes HSFA2 and DREB2C were expressed in an elite wheat genotype Akbar, Fakhre-e-Bhakhar under constitutive CAMV35S promoter and stress inducible rd29 Promoters. The shoot cut method was used for the Agrobacterium-mediated transformation and putative transformants were selected on kanamycin 50 mg/L. The resultant transformants were tested through PCR for transgene integration whereas expression analysis was carried out through realtime qPCR. Expression of both of the aforementioned genes was found to be higher under rd29 promoter as compared with transgene(s) expression under CAMV35S promoter. In the bioassay, transgenic wheat plants demonstrated significant tolerance to stress, exhibiting only minor spotting under constitutive expression conditions. Upon exposure to stress, these plants showed exceptional resistance to stripe rust, producing large, bold grains compared to individual trait expressions and negative controls. Subsequently, the DREB2C gene was knocked out to determine if stripe rust control was specifically attributed to this gene. Following the knockout, the onset of stripe rust was comparable to that of the negative control. This led to the conclusion that pyramiding the DREB2C gene with HSFA2 through dual expression represents a novel and highly effective strategy for controlling the widespread stripe rust in wheat. This approach also offers resistance to high temperatures (above 32 °C) from the pollination stage through to maturity.

Divergence-free cut finite element methods for Stokes flow

We develop two unfitted finite element methods for the Stokes equations based on Hdiv\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extbf{H}^{{{\\,\ extrm{div}\\,}}}$$\\end{document}-conforming finite elements. Both cut finite element methods exhibit optimal convergence order for the velocity, pointwise divergence-free velocity fields, and well-posed linear systems, independently of the position of the boundary relative to the computational mesh. The first method is a cut finite element discretization of the Stokes equations based on the Brezzi–Douglas–Marini (BDM) elements and involves interior penalty terms to enforce tangential continuity of the velocity at interior edges in the mesh. The second method is a cut finite element discretization of a three-field formulation of the Stokes problem involving the vorticity, velocity, and pressure and uses the Raviart–Thomas (RT) space for the velocity. We present mixed ghost penalty stabilization terms for both methods so that the resulting discrete problems are stable and the divergence-free property of the Hdiv\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\ extbf{H}^{{{\\,\ extrm{div}\\,}}}$$\\end{document}-conforming elements is preserved also on unfitted meshes. In both methods boundary conditions are imposed weakly. We show that imposing Dirichlet boundary conditions weakly introduces additional challenges; (1) The divergence-free property of the RT and the BDM finite elements may be lost depending on how the normal component of the velocity field at the boundary is imposed. (2) Pressure robustness is affected by how well the boundary condition is satisfied and may not hold even if the incompressibility condition holds pointwise. We study two approaches of weakly imposing the normal component of the velocity at the boundary; we either use a penalty parameter and Nitsche’s method or a Lagrange multiplier method. We show that appropriate conditions on the velocity space has to be imposed when Nitsche’s method or penalty is used. Pressure robustness can hold with both approaches by reducing the error at the boundary but the price we pay is seen in the condition numbers of the resulting linear systems, independent of if the mesh is fitted or unfitted to the boundary.

Geometrical Penrose tilings are characterized by their 1-atlas

Penrose rhombus tilings are tilings of the plane by two decorated rhombi such that the decorations match at the junction between two tiles (like in a jigsaw puzzle). In dynamical terms, they form a tiling space of finite type. If we remove the decorations, we get, by definition, a sofic tiling space that we here call geometrical Penrose tilings. Here, we show how to compute the patterns of a given size which appear in these tilings by three different methods: two based on the substitutive structure of the Penrose tilings and the last on their definition by the cut and projection method. We use this to prove that the geometrical Penrose tilings are characterized by a small set of patterns called vertex-atlas, i.e., they form a tiling space of finite type. Though considered as folklore, no complete proof of this result has been published, to our knowledge.

Development of Fuzzy-AHP and WPM based MCDM Model for Mining Method Selection

The study aims to select the proper mining method for underground metal mines using the Fuzzy-Analytical Hierarchical Process (FAHP) and Weighted Product Method (WPM). The study considered various deposit characteristics such as dip of the orebody, orebody thickness, shape of the orebody, depth of the orebody from the surface, and grade distribution. Based on these characteristics block caving, sublevel stoping, sublevel caving, room and pillar, shrinkage stoping, cut and fill stoping methods are evaluated. FAHP method calculates the weights for each deposit characteristic and WPM calculates the scores of mining methods for the given mine body characteristic. FAHP and WPM models are applied to a uranium mine in India. The appropriate extraction method for the considered mine is found as cut and fill stoping. The same method is also used at the mining location.

A bound preserving cut discontinuous Galerkin method for one dimensional hyperbolic conservation laws

In this paper we present a family of high order cut finite element methods with bound preserving properties for hyperbolic conservation laws in one space dimension. The methods are based on the discontinuous Galerkin framework and use a regular background mesh, where interior boundaries are allowed to cut through the mesh arbitrarily. Our methods include ghost penalty stabilization to handle small cut elements and a new reconstruction of the approximation on macro-elements, which are local patches consisting of cut and un-cut neighboring elements that are connected by stabilization. We show that the reconstructed solution retains conservation and order of convergence. Our lowest order scheme results in a piecewise constant solution that satisfies a maximum principle for scalar hyperbolic conservation laws. When the lowest order scheme is applied to the Euler equations, the scheme is positivity preserving in the sense that positivity of pressure and density are retained. For the high order schemes, suitable bound preserving limiters are applied to the reconstructed solution on macro-elements. In the scalar case, a maximum principle limiter is applied, which ensures that the limited approximation satisfies the maximum principle. Correspondingly, we use a positivity preserving limiter for the Euler equations, and show that our scheme is positivity preserving. In the presence of shocks additional limiting is needed to avoid oscillations, hence we apply a standard TVB limiter to the reconstructed solution. The time step restrictions are of the same order as for the corresponding discontinuous Galerkin methods on the background mesh. Numerical computations illustrate accuracy, bound preservation, and shock capturing capabilities of the proposed schemes.

An open-source MATLAB toolbox for 3D block cutting and 3D mesh cutting in geotechnical engineering

This study presents a simple approach and its associated MATLAB toolbox for 3D block cutting and mesh cutting. The approach is suitable for the meshes of numerical methods including the Key Block Theory (KBT), the Discontinuous Deformation Analysis (DDA), the Numerical Manifold Method (NMM), and the cut Finite Element Method (Cut-FEM). The strategy is based on calculations on convex bodies. It uses two different forms of representation: the geometric representation which includes vertices and faces, and the algebraic representation which consists of inequalities. The cutting was implemented on the algebraic representation, and the resulting inequalities were converted into a geometric representation. The above strategy turned out to be robust and straightforward to execute, at the cost of a general body being regarded as a combination of convex bodies. The efficiency guarantee was considered through pre-checking algorithms. The source code was provided, as well as some simple examples.

Bilinear branch and check for unspecified parallel machine scheduling with shift consideration

This paper tackles the complex challenge of team formations, assignments, and job schedules within the static Unspecified Parallel Machine Flexible Resource Scheduling problem, specifically incorporating shift considerations. In existing literature, teams are often simplified as machines that operate continuously throughout the day without any interruptions. However, in reality, teams require breaks between shifts and cannot work continuously within a day. Therefore, we introduce shift considerations to ensure that teams do not work in consecutive shifts. We consider flexible workers, capable of performing any job, who are distributed among different teams in different shifts to undertake various jobs. The number of teams in each shift is a decision variable. The duration of each job is determined by the number of workers in a team assigned to it. The objective function is to minimize the makespan, representing the overall schedule completion time, while adhering to precedence constraints. We formulate an integer linear programming model for the proposed problem and develop a novel bilinear branch and check algorithm that introduces valid bilinear inequalities to accelerate convergence. The numerical results confirm that our algorithm’s performance optimally solves problems up to 35 jobs within a reasonable timeframe, surpassing the efficiency of the branch and cut method of IBM CPLEX and the classical branch and check algorithm.

SPA: Annotating Small Object with a Single Point in Remote Sensing Images

Detecting oriented small objects is a critical task in remote sensing, but the development of high-performance deep learning-based detectors is hindered by the need for large-scale and well-annotated datasets. The high cost of creating these datasets, due to the dense and numerous distribution of small objects, significantly limits the application and development of such detectors. To address this problem, we propose a single-point-based annotation approach (SPA) based on the graph cut method. In this framework, user annotations act as the origin of positive sample points, and a similarity matrix, computed from feature maps extracted by deep learning networks, facilitates an intuitive and efficient annotation process for building graph elements. Utilizing the Maximum Flow algorithm, SPA derives positive sample regions from these points and generates oriented bounding boxes (OBBOXs). Experimental results demonstrate the effectiveness of SPA, with at least a 50% improvement in annotation efficiency. Furthermore, the intersection-over-union (IoU) metric of our OBBOX is 3.6% higher than existing methods such as the “Segment Anything Model”. When applied in training, the model annotated with SPA shows a 4.7% higher mean average precision (mAP) compared to models using traditional annotation methods. These results confirm the technical advantages and practical impact of SPA in advancing small object detection in remote sensing.

Novel Cardiovascular Stent Based on Hibiscus-Aestivation-Inspired Auxetic Unit Cell

Conventional stents have some limitations, such as dogboning and foreshortening, that can lead to issues like in-stent restenosis and thrombosis. Negative Poisson's ratio stents, called auxetic stents, are known as a solution to overcome these challenges due to their unique deformation mechanism. Auxetic stents are scale-independent, and their behavior depends solely on their geometry. In this study, a novel auxetic unit cell inspired by aestivation mechanism of the Hibiscus flower is designed, developed, and implemented in plane, and a tube to achieve a novel NPR cardiovascular stent. The stent structure is fabricated using two methods, including a novel 7-axis laser cut method capable of producing stents the same size as human blood vessels from an SS 316 L tube, and fused deposition modelling 3D printing at a scale 20 times larger than the metallic sample using PLA filaments. Novel laser cut effectively overcame some challenges in laser cutting stents, including HAZ and thermal shocks. SEM images are taken from the laser cut sample, and the manufacturing method's accuracy and surface quality are investigated. Fabricated metallic and polymeric stent samples proposed negative Poisson's ratio equal to 0.89 with an average of 4.38 and 14.8% errors, respectively, compared with finite element analysis. Finally, the structure's stress, strain energy distribution pattern, and unit cell distribution have been examined. Furthermore, the stent thickness parameter, drug release patch application, and stent implementation process are also investigated using FEM method. Proposed geometry in stent application showed solutions to conventional positive Poisson's ratio stent challenges.

Space-time CutFEM on overlapping meshes II: simple discontinuous mesh evolution

We present a cut finite element method for the heat equation on two overlapping meshes: a stationary background mesh and an overlapping mesh that evolves inside/“on top” of it. Here the overlapping mesh is prescribed by a simple discontinuous evolution, meaning that its location, size, and shape as functions of time are discontinuous and piecewise constant. For the discrete function space, we use continuous Galerkin in space and discontinuous Galerkin in time, with the addition of a discontinuity on the boundary between the two meshes. The finite element formulation is based on Nitsche’s method. The simple discontinuous mesh evolution results in a space-time discretization with a slabwise product structure between space and time which allows for existing analysis methodologies to be applied with only minor modifications. We follow the analysis methodology presented by Eriksson and Johnson (SIAM J Numer Anal 28(1):43–77, 1991; SIAM J Numer Anal 32(3):706–740, 1995). The greatest modification is the introduction of a Ritz-like “shift operator” that is used to obtain the discrete strong stability needed for the error analysis. The shift operator generalizes the original analysis to some methods for which the discrete subspace at one time does not lie in the space of the stiffness form at the subsequent time. The error analysis consists of an a priori error estimate that is of optimal order with respect to both time step and mesh size. We also present numerical results for a problem in one spatial dimension that verify the analytic error convergence orders.

Space-time CutFEM on overlapping meshes I: simple continuous mesh motion

We present a cut finite element method for the heat equation on two overlapping meshes: a stationary background mesh and an overlapping mesh that moves around inside/“on top” of it. Here the overlapping mesh is prescribed by a simple continuous motion, meaning that its location as a function of time is continuous and piecewise linear. For the discrete function space, we use continuous Galerkin in space and discontinuous Galerkin in time, with the addition of a discontinuity on the boundary between the two meshes. The finite element formulation is based on Nitsche’s method and also includes an integral term over the space-time boundary between the two meshes that mimics the standard discontinuous Galerkin time-jump term. The simple continuous mesh motion results in a space-time discretization for which standard analysis methodologies either fail or are unsuitable. We therefore employ what seems to be a relatively uncommon energy analysis framework for finite element methods for parabolic problems that is general and robust enough to be applicable to the current setting. The energy analysis consists of a stability estimate that is slightly stronger than the standard basic one and an a priori error estimate that is of optimal order with respect to both time step and mesh size. We also present numerical results for a problem in one spatial dimension that verify the analytic error convergence orders.

Assessment of residual prestress in existing concrete bridges: The Kalix bridge

The direct socio-economic consequences of the deterioration of aging infrastructure systems have triggered a continuous process of revising and updating current design standards and guidelines for critical network components. Specifically, long-term degradation processes demand the analysis and evaluation of vital structural assets such as prestressed concrete bridges. It is crucial to develop theoretically consistent, user-friendly, and non-destructive methodologies that engineering professionals can employ to prevent and mitigate potential catastrophic outcomes during the service life of these bridges. This study provides a thorough review of the available testing methods employed over the years for prestressed concrete bridges and introduces a comprehensive framework for evaluating existing methods for residual prestress force assessment. Through a multi-criteria selection process, the three most feasible tests were designed and carried out on an existing 66-year-old balanced cantilever box girder bridge exposed to freezing temperatures that affected the instrumentation plan and test execution. Finally, predictive models compliant with standard codes were calibrated based on the experimental results and the life cycle loss of prestress forces was evaluated to assess relevant bounding intervals. Findings reveal limited on-site testing and discrepancies between calculated residual forces and predictions by standard codes. The saw cut method showed a 18% difference from the initial applied prestress according to the prestress protocol, suggesting the use of a cover meter and concrete modulus evaluation for improved accuracy. The strand cutting method resulted in a 14% difference, emphasizing the need for stress redistribution assessment. The second-order deflection method showed a 6% difference, indicating a focus on enhanced boundary conditions and thorough sensitivity analysis for future investigations.

Unwrapping phase contrast MRI by iterative graph cuts.

To develop and evaluate a phase unwrapping method for cine phase contrast MRI based on graph cuts. A proposed Iterative Graph Cuts method was evaluated in 10 cardiac patients with two-dimensional flow quantification which was repeated at low venc settings to provoke wrapping. The images were also unwrapped by a path-following method (ROMEO), and a Laplacian-based method (LP). Net flow was quantified using semi-automatic vessel segmentation. High venc images were also wrapped retrospectively to asses the residual amount of wrapped voxels. The absolute net flow error after unwrapping at venc = 100cm/s was 1.8mL, which was 0.83mL smaller than for LP. The repeatability error at high venc without unwrapping was 2.5mL. The error at venc = 50cm/s was 7.5mL, which was 8.2mL smaller than for ROMEO and 5.7mL smaller than for LP. For retrospectively wrapped images with synthetic venc of 100/50/25cm/s, the residual amount of wrapped voxels was 0.00/0.12/0.79%, which was 0.09/0.26/8.0percentage points smaller than for LP. With synthetic venc of 25cm/s, omitting magnitude information resulted in 3.2 percentage points more wrapped voxels, and only spatial/temporal unwrapping resulted in 4.6/21 percentage points more wrapped voxels compared to spatiotemporal unwrapping. Iterative Graph Cuts enables unwrapping of cine phase contrast MRI with very small errors, except for at extreme blood velocities, with equal or better performance compared to ROMEO and LP. The use of magnitude information and spatiotemporal unwrapping is recommended.

An Implicitly Extended Crank–Nicolson Scheme for the Heat Equation on a Time-Dependent Domain

We consider a time-stepping scheme of Crank–Nicolson type for the heat equation on a moving domain in Eulerian coordinates. As the spatial domain varies between subsequent time steps, an extension of the solution from the previous time step is required. Following Lehrenfeld and Olskanskii (ESAIM: M2AN 53(2):585–614, 2019), we apply an implicit extension based on so-called ghost-penalty terms. For spatial discretisation, a cut finite element method is used. We derive a complete a priori error analysis in space and time, which shows in particular second-order convergence in time under a parabolic CFL condition. Finally, we present numerical results in two and three space dimensions that confirm the analytical estimates, even for much larger time steps.