Compression Applications Research Articles

Homogeneous Image Compression Techniques with the Shannon-Fano Algorithm

Compression is a field that needed at this time where increasingly high-tech digital and computing makes it possible to process data in a size that is large enough like multimedia. Compression needed to keep pressing the storage media consumption of data and information stored on computer media. The Shannon-Fano compression algorithm is one of the well-known compression algorithms and is useful in saving data storage space. Shannon-Fano compression algorithms can be performed on text and digital images. In this study applying the Shannon-Fano method to homogeneous digital images using applications created with the MATLAB Program. The product of this research will be tested using several images taken using a webcam. The product tested to find out whether the coding used is correct or has errors. The product will be successful if it can reduce the size of the compressed image from the original image. Homogeneous images that have tested using the Shannon-Fano image compression application have an average compression ratio value of 52%. The size of the compression results reaches half of the original image. The Shannon-Fano compression algorithm detects the number of times that characters appear in each experiment, then the coding of the frequency of characters appearing in binary numbers.

Multiphase field theory for ferroelastic domain switching with an application to tetragonal zirconia

A multiphase field theory and corresponding finite element simulations are developed to describe ferroelastic domain switching in bulk polydomain tetragonal zirconia (t′-zirconia). We consider the ferroelastic switching as mechanical twinning in our model which differs from the Landau-Devinshire theory used in ferroelectric thin films. The approach is advanced in several directions: the thermodynamic potential is developed, introducing interface tension at the domain wall with a multiphase field framework; the ferroelastic features, such as spontaneous strain, coercive stress and hysteresis loop, are explicitly derived from the potential; and a penalizing term in interface energy is introduced to constrain the switching paths between different domains for correctly describing the hysteresis. The phase field model is applied towards prediction of switching rules among three domains of an externally stressed t′-zirconia. Numerical simulations demonstrate fair agreement between phase field solutions and experimental observations that the two sets of domains grow at the expense of the third set upon application of uniaxial compression. The simulations also reproduced a phenomenon that the domain switching occurs and develops inside the colony domain pattern, i.e., the switching rules are dominated by the applied stress tensor and the pre-existing domain patterns of materials. The developed approach can be extended to study the domain switching of any pure ferroelastic material or ferroelectrics subjected to applied stress in the absence of an electric field.

Image compression system with an optimisation of compression ratio

The fundamental goal of image data compression is to set an optimal compression ratio while maintaining an acceptable reproduction quality. This study describes the principles of design of image compression system that automatically sets an optimal compression ratio for particular image content by identifying the image compression method while maintaining a tolerable reproduction quality. The proposed image compression system employs subjective and objective criteria for an assessment of the quality of the image compression system. The supervised artificial neural network is used to identify a compression method among different compression techniques by using subjective criterion. An objective criterion is used to determine an optimal compression ratio, which is calculated by using linear regression analysis that establishes analytical expression between a compression ratio, a property of an image and a reconstructed quality of an image. It was proved that the system is an effective tool for medical image compression applications.

Gaussian-product subdivision surfaces

Probabilistic distribution models like Gaussian mixtures have shown great potential for improving both the quality and speed of several geometric operators. This is largely due to their ability to model large fuzzy data using only a reduced set of atomic distributions, allowing for large compression rates at minimal information loss. We introduce a new surface model that utilizes these qualities of Gaussian mixtures for the definition and control of a parametric smooth surface. Our approach is based on an enriched mesh data structure, which describes the probability distribution of spatial surface locations around each vertex via a Gaussian covariance matrix. By incorporating this additional covariance information, we show how to define a smooth surface via a nonlinear probabilistic subdivision operator based on products of Gaussians, which is able to capture rich details at fixed control mesh resolution. This entails new applications in surface reconstruction, modeling, and geometric compression.

Superficial femoral artery blood flow with intermittent pneumatic compression of the lower leg applied during walking exercise and recovery.

The purpose of this study was to determine if muscle blood flow during walking exercise and postexercise recovery can be augmented through the application of intermittent compression of the lower legs applied during the diastolic phase of the cardiac cycle. Results from four conditions were assessed: no compression (NoComp), compression during walking (ExComp), compression during postexercise recovery (RecComp), and compression applied throughout (AllComp). Superficial femoral artery (SFA) blood flow was measured (Doppler ultrasound) during rest and postexercise recovery. Mean arterial blood pressure (MAP, finger photoplethysmography) was used to calculate vascular conductance as VC = SFA flow/MAP. Near infrared spectroscopy measured changes in oxygenated (O2Hb) and deoxygenated hemoglobin concentration throughout the test. Compression during exercise increased SFA blood flow measured over the first 15 s of postexercise recovery (AllComp: 532.2 ± 123.1 mL/min; ExComp: 529.8 ± 99.2 mL/min) compared with NoComp (462.3 ± 87.3 mL/min P < 0.05) and corresponded to increased VC (NoComp: 4.7 ± 0.9 mL·min-1·mmHg-1 versus ExComp: 5.5 ± 1.0 mL·min-1·mmHg-1, P < 0.05). Similarly, compression throughout postexercise recovery also resulted in increased SFA flow (AllComp: 190.5 ± 57.1 mL/min; RecComp: 158.7 ± 49.1 mL/min versus NoComp: 108.8 ± 28.5 mL/min, P < 0.05) and vascular conductance. Muscle contractions during exercise reduced total hemoglobin with O2Hb comprising ~57% of the observed reduction. Compression during exercise augmented this reduction (P < 0.05) with O2HB again comprising ~55% of the reduction. Total hemoglobin was reduced with compression during postexercise recovery (P < 0.05) with O2Hb accounting for ~40% of this reduction. Results from this study indicate that intermittent compression applied during walking and during postexercise recovery enhanced vascular conductance during exercise and elevated postexercise SFA blood flow and tissue oxygenation during recovery.NEW & NOTEWORTHY Intermittent compression mimics the mechanical actions of voluntary muscle contraction on venous volume. This study demonstrates that compression applied during the diastolic phase of the cardiac cycle while walking accentuates the actions of the muscle pump resulting in increased immediate postexercise muscle blood flow and vascular conductance. Similarly, compression applied during the recovery period independently increased arterial flow and tissue oxygenation, potentially providing conditions conducive to faster recovery.

Physical and Edema Therapy Management of Amyloidosis in the Acute Care Setting: A Case Report

Background and Purpose: Currently, there are no formal guidelines describing rehabilitation interventions for those with amyloidosis. This case report explores the application of physical and edema therapy interventions, including external compression, for a patient with a diagnosis of light-chain (AL) amyloidosis and functionally limiting orthostatic hypotension in the acute care setting. Case Description: A 52-year-old man with a diagnosis of immunoglobulin AL amyloidosis presented to the acute care setting with progressed orthostatic hypotension, bilateral lower extremity edema, and episodes of syncope. The patient spent 17 days in the inpatient setting and received physical therapy (PT) and edema therapy through the inpatient lymphedema service. Rehabilitation focused on exercise, compression, and behavioral and educational interventions over the course of 9 PT sessions and 7 edema therapy sessions. Outcomes: Before interventions, the patient was unable to safely ambulate at home due to syncope. He progressed to being able to ambulate 1560 ft with seated rests. The patient demonstrated decreased limb circumferential measurements, improved performance on the 6-Minute Walk Test, improved ability to self-manage orthostatic hypotension and edema, and increased participation in activities of daily living. Discussion: The combination of physical and edema therapy services may have compensated for orthostatic hypotension and improved standing tolerance. The patient's blood urea nitrogen and brain natriuretic peptide levels may have improved because of the application of external compression. Overall, the patient experienced decreased limb size, increased exercise tolerance, decreased syncopal episodes, and improved quality of life without changes in pharmacologic management or adverse events.

Pipeline architectures of Three-dimensional daubechies wavelet transform using hybrid method

&lt;span&gt;The application of three-dimensional (3-D) medical image compression systems uses several building blocks for its computationally intensive algorithms to perform matrix transformation operations. Complexity in addressing large medical volumes data has resulted in vast challenges from a hardware implementation perspective. This paper presents an approach towards very-large-scale-integration (VLSI) implementation of 3-D Daubechies wavelet transform for medical image compression. Discrete wavelet transform (DWT) algorithm is used to design the proposed architectures with pipelined direct mapping technique. Hybrid method use a combination of hardware description language (HDL) and G-code, where this method provides an advantage compared to traditional method. The proposed pipelined architectures are deployed for adaptive transformation process of medical image compression applications. The soft IP core design was targeted on to Xilinx field programmable gate array (FPGA) single board RIO (sbRIO 9632). Results obtained for 3-D DWT architecture using Daubechies 4-tap (Daub4) implementation exhibits promising results in terms of area, power consumption and maximum frequency compared to Daubechies 6-tap (Daub6).&lt;/span&gt;

Ankle Brachial Pressure Index and compression application: Review summary

Venous leg ulcers (VLUs) are a significant complication amongst persons with chronic venous insufficiency (CVI) that frequently follow a cycle of healing and recurrence. Current clinical practice guidelines (CPGs) recommend applying below knee compression to improve VLU healing. Compression could be applied if the Ankle Brachial Pressure Index (ABPI) rules out significant arterial disease, as sufficient peripheral arterial circulation is necessary to ensure safe compression use. We conducted a content analysis of 13 global CPGs on the accuracy of recommendations related to ABPI and compression application. Eight CPGs indicated that compression is recommended when the ABPI is between 0.8 and 1.2 mmHg. However, this review found there is disagreement between 13 global VLU CPGs, with a lack of clarity on whether or not compression is indicated for patients with ABPIs between 0.6 and 0.8 mmHg. Some CPGs recommend reduced compression for treatment of VLUs, while others do not recommend any type of compression at all. This has implications for when it is safe to apply compression, and the inconsistency in evidence indicates that specialist advice may be required at levels beyond the ABPI “safe” range listed above.

Mechanics of tablet formation: a comparative evaluation of percolation theory with classical concepts

The present study is based on the fundamentals of percolation theory and its application in understanding compression and compaction of powder materials. Four materials, i.e. carbamazepine, microcrystalline cellulose, crospovidone and croscarmellose sodium, with dissimilar deformation and compaction behavior were selected to validate the hypotheses of percolation phenomenon. The values of two percolation thresholds, i.e. bond and site, corresponding to the lower and intermediate compression pressures, were determined using Heckel equation. The compactibility of powder materials was evaluated using classical models as well as the power law equation. The values of percolation thresholds were found to better assess the deformation behavior of powder materials compared to the values of mean yield pressure. The power law equation demonstrated better prediction of compactibility of powder materials compared to the classical models. The value of the critical exponent, q, determined using power law equation by plotting tensile strength vs. normalized relative density of powder compacts was found to be closer to the theoretical value of 2.70. Furthermore, the theoretical knowledge of percolation thresholds of individual powder components in the binary mixture was found to be helpful in improving compaction properties of the poorly compactible material, i.e. carbamazepine. Thus percolation theory can be helpful in predicting compression and compaction behavior of powder materials and serve as a potent tool for the successful design of tablet formulations.

Hyperphysiological compression of articular cartilage induces an osteoarthritic phenotype in a cartilage-on-a-chip model.

Owing to population aging, the social impact of osteoarthritis (OA)-the most common musculoskeletal disease-is expected to increase dramatically. Yet, therapy is still limited to palliative treatments or surgical intervention, and disease-modifying OA (DMOA) drugs are scarce, mainly because of the absence of relevant preclinical OA models. Therefore, in vitro models that can reliably predict the efficacy of DMOA drugs are needed. Here, we show, using a newly developed microphysiological cartilage-on-a-chip model that enables the application of strain-controlled compression to three-dimensional articular cartilage microtissue, that a 30% confined compression recapitulates the mechanical factors involved in OA pathogenesis and is sufficient to induce OA traits. Such hyperphysiological compression triggers a shift in cartilage homeostasis towards catabolism and inflammation, hypertrophy, and the acquisition of a gene expression profile akin to those seen in clinical osteoarthritic tissue. The cartilage on-a-chip model may enable the screening of DMOA candidates.

Persistent SIRS and non-alcohol etiology of AP are associated with oral feeding intolerance in AP: Results from an international, multicenter, prospective cohort study

Venous leg ulcers represent the most common chronic wound problem managed in Australian primary care. Despite the prevalence of the condition, there is an evidence-practice gap in both diagnosis and management of venous leg ulcers.We used the Theoretical Domains Framework to identify barriers and enablers perceived by primary care practitioners in implementing venous leg ulcer guidelines in clinical practice.We collected data to explore the experiences of practice nurses and general practitioners related to their use of clinical practice guidelines in management of venous leg ulcers.We recruited participants from primary care settings located in metropolitan and rural areas across Victoria, Australia.We recruited general practitioners (15) and practice nurses (20).We conducted 35 semi-structured face-to-face and telephone interviews. Content analysis of health practitioners’ statements was performed and barriers to implementing clinical practice guidelines were mapped across the Theoretical Domains Framework theoretical domains.Six main domains from the Theoretical Domains Framework (Environmental context and resources, Knowledge, Skills, Social influences, Social/Professional Role and Identity and Belief about Capabilities) best explained these barriers and enablers. Many participants were not aware of venous leg ulcer clinical practice guidelines. Those that were aware, stated that finding and accessing guidelines was challenging and most participants relied on other sources of information. Venous leg ulcer management was greatly influenced by professional experience and suggestions from colleagues. Other barriers included busy clinical practice, absence of handheld Doppler ultrasonography, insufficient skills and a lack of confidence related to the use of technology to rule out arterial involvement prior to compression application, a particular skill related to venous leg ulcer management that will impact on healing outcomes.We identified a number of barriers and the lack of enablers that influence the uptake of venous leg ulcer clinical practice guidelines in primary care. This paper adds a theoretically sound, systematic approach for understanding and addressing the behaviour change required to improve translation of venous leg ulcer clinical practice guidelines in clinical practice.Tweetable abstract: The need to optimise venous leg ulcer clinical practice guidelines (CPG) has never been greater as the current estimate of health cost is AUD3billion and increasing due to rising epidemics of diabetes and obesity. We found most primary care health practitioners are unaware of CPG and this will impact on health and healing outcomes in Australian primary care.

Planar AFM macro-probes to study the biomechanical properties of large cells and 3D cell spheroids

The ability to measure mechanical response of cells under applied load is essential for developing more accurate models of cell mechanics and mechanotransduction. Living cells have been mechanically investigated by several approaches. Among them, atomic force microscopy (AFM) is widely used thanks to its high versatility and sensitivity. In the case of large cells or 3D multicellular aggregates, standard AFM probes may not be appropriate to investigate the mechanical properties of the whole biological system. Owing to their size, standard AFM probes can compress only a single somatic cell or part of it. To fill this gap, we have designed and fabricated planar AFM macro-probes compatible with commercial AFM instruments. The probes are constituted of a large flat compression plate, connected to the chip by two flexible arms, whose mechanical characteristics are tuned for specific biological applications. As proof of concept, we have used the macro-probes to measure the viscoelasticity of large spherical biological systems, which have a diameter above 100 μm: human oocytes and 3D cell spheroids. Compression experiments are combined with visual inspection, using a side-view configuration imaging, which allows us to monitor the sample morphology during the compression and to correlate it with the viscoelastic parameters. Our measurements provide a quantitative estimate of the relaxation times of such biological systems, which are discussed in relation to data present in literature. The broad applicability of the AFM macro-probes can be relevant to study the biomechanical features in any biological process involving large soft materials. Statement of SignificanceThe understanding of the role of physical factors in defining cell and tissue functions requires to develop new methods or improve the existing ones to accurately measure the biomechanical properties. AFM is a sensitive and versatile tool to measure the mechanical features from single proteins to single cells. When cells or cell aggregates exceed few tens of microns, AFM suffers from limitations. On these biological systems the control of the contact area and the application of a precise uniform compression becomes crucial. A modification of the standard cantilevers fabrication allowed us obtaining AFM macro-probes, having large planar contact area and spring constant suitable for biological investigations. They were demonstrated valuable to characterize the mechanical properties of large hierarchical biological systems.

Chaotic Pattern Array for Single-Pixel Imaging

Single-pixel imaging (SPI) is an emerging framework that can capture the image of a scene via a single-point detector at a considerably low cost. It measures the projection at the detector of the scene under view with certain patterns. One can reconstruct the image of the scene via post-processing the measurements modulated by the patterns. However, the most commonly-used random patterns are not always desirable in many applications, especially for real-time, resource-limited occasions, due to their high memory requirement and huge cost in software and hardware implementation. In this paper, a chaotic pattern array is proposed for the SPI architecture. Compared with random patterns, the proposed chaotic pattern array can not only promise to increase the capabilities of the SPI device, but can also reduce the memory cost and complexity of hardware implementation in the meantime. Moreover, convincing experiment results are given to illustrate that the proposed pattern array is suitable for single-pixel cameras, as well as other compressive imaging applications.

Evaluating Effectiveness of Nasal Compression With Tranexamic Acid Compared With Simple Nasal Compression and Merocel Packing: A Randomized Controlled Trial

The primary objective of this study is to compare the effectiveness of 3 treatment protocols to stop anterior epistaxis: classic compression, nasal packing, and local application of tranexamic acid. It also aims to determine the frequency of rebleeding after each of these protocols. This single-center, prospective, randomized controlled study was conducted with patients who had spontaneous anterior epistaxis. The study compared the effect of 3 treatment options, tranexamic acid with compression but without nasal packing, nasal packing (Merocel), and simple nasal external compression, on the primary outcome of stopping anterior epistaxis bleeding within 15 minutes. Among the 135 patients enrolled, the median age was 60 years (interquartile range 25% to 75%: 48 to 72 years) and 70 patients (51.9%) were women. The success rate in the compression with tranexamic acid group was 91.1% (41 of 45 patients); in the nasal packing group, 93.3% (42 of 45 patients); and in the compression with saline solution group, 71.1% (32 of 45 patients). There was an overall statistically significant difference among the 3 treatment groups but no significant difference in pairwise comparison between the compression with tranexamic acid and nasal packing groups. In regard to no rebleeding within 24 hours, the study found rates of 86.7% in the tranexamic acid group, 74% in the nasal packing group, and 60% in the compression with saline solution group. Applying external compression after administering tranexamic acid through the nostrils by atomizer stops bleeding as effectively as anterior nasal packing using Merocel. In addition, the tranexamic acid approach is superior to Merocel in terms of decreasing rebleeding rates.

Hilotherapy treatment in postoperative surgery in a patient with severe osahs

Background: Hilotherapy consists in the application of cold compression at a regulated temperature through a face mask. Craniomaxillofacial surgery causes immediate postoperative pain, edema, and functional limitations. Hilotherapy delivers continue cooled water to the face at 15 °C, helping prevent this common outcome of craniomaxillofacial surgeries. (Bates et al., 2016).

Sustainability assessment of recycled aggregates concrete mixes containing industrial by-products

Virgin natural aggregates make up approximately 80–85% of the volume of concrete commonly used by Western Australian councils in their infrastructure. These councils generate a huge amount of construction and demolition (C&D) waste, most of which is sent to landfill. While C&D waste can potentially be used in pavements, only 22% of the total 1.5M tonnes of C&D waste generated in Western Australia (WA) each year is recycled. Experimental tests conducted in the Civil Engineering Laboratory of Curtin University have confirmed that concrete mixes utilizing recycled aggregates, fly ash (FA), and silica fume (SF) are structurally sound. The experimental results have shown that these new concrete formulations can potentially be considered for higher compressive strength applications. Concrete containing a maximum of 100% C&D waste from aggregate has been found to exceed the compressive strength (i.e. 40 MPa) required for most structural applications. Importantly, the potential use of this new concrete in WA residential flooring could divert significant amounts of C&D waste from landfill. Life cycle assessment of these concrete mixes suggested that the mixes using 50% natural aggregates, 50% recycled aggregates, and between 10% and 40% of by-products as cementitious materials have the highest reduction potential for global warming impact and embodied energy because of their higher compressive strength. Between 14 and 21% of cumulative energy consumption and 25–31% of global warming, impacts could be avoided with the use of 50 natural coarse aggregate (NA)+50100 recycled coarse aggregate (RA)+90 ordinary Portland cement (OPC)+10SF and 50NA+50RA+60OPC+30FA+10SF concrete formulations instead of 100NA (natural aggregate)+100OPC concrete to provide the same compressive strength. These two alternative mixes were found to reduce the cost by 7%–18%. The recycling of unused C&D wastes could also provide new employment opportunities and significant improvements in resources conservation, including land and biodiversity. Furthermore, between 90 and 280 GWh, energy can potentially be saved because of the replacement of energy-intensive natural aggregates with different mixes of recycled aggregate concrete.

Development of a traumatic cervical dislocation spinal cord injury model with residual compression in the rat

BackgroundPreclinical spinal cord injury models do not represent the wide range of biomechanical factors seen in human injuries, such as spinal level, injury mechanism, velocity of spinal cord impact, and residual compression. These factors may be responsible for differences observed between experimental and clinical study results, especially related to the controversial issue of timing of surgical decompression. New methodSomatosensory Evoked Potentials were used to: a) characterize residual compression depths in a dislocation model, and b) evaluate the physiological effect of whether or not the spinal cord was decompressed following the initial injury, prior to the application of residual compression. Modifications to vertebral clamps and the development of a novel surgical frame allowed us to conduct surgical and injury procedures in a controlled manner without the risk of additional damage to the spinal cord. Behavioural outcomes were evaluated following varying dislocation displacements, in addition to the survivability of 4 h of residual compression following a traumatic injury. ResultsResidual compression immediately following the initial dislocation demonstrated significantly different electrophysiological response compared to when the residual compression was delayed. Comparison with existing methodThere are currently no other residual compression models that utilize a dislocation injury mechanism. Many residual compression studies have demonstrated the effectiveness of early decompression, however the compression of the spinal cord is often not representative of clinical traumatic injuries. Preclinical studies typically model residual compression using a sustained force through quasi-static application, when human injuries often occur at high velocities, followed by a sustained displacement occlusion of the spinal canal. ConclusionsThis study has validated several novel procedural approaches and injury parameters, and provided critical details to implement in the development of a traumatic cervical dislocation SCI model with residual compression.

InP AAC for data compression applications

The authors propose a 2 × 2 asymmetric adiabatic coupler (AAC) indium phosphide (InP) photonic integrated circuit (PIC), suitable for tunable power applications such as all-optical data processing. The device was idealised as the key building block in Haar transform network used for image compression, allowing to perform the necessary separate addition and subtraction of incoming input signals at its output ports. The tunable behaviour of the coupler was demonstrated experimentally for addition/subtraction and splitting (with experimental coupling ratios of 77:23/14:86 and 50:50, respectively) through phase control. The use of the developed InP PIC enables a low footprint structure design together with the high-quality active components (lasers, photodetectors and phase modulators) of Fraunhofer Gesellschaft Heinrich Hertz Institute design toolkit. The proposed study provides a full experimental characterisation of the AAC, exploring its tuning properties and enabling further usage in a plethora of applications in high processing computing and data communications.

Clinical application exploration of magnetic compression technology in the treatment of complex biliary strictures

It is intractable to Complex biliary stricture therapy after liver transplantation and other biliary operations is intractable. The routine therapies are to place stents with ERCP or do choledochojejunostomy. The former, however, is of little effect for patients with complex biliary stricture or completed obstruction. And the latter is more difficult and is with high rate postoperative complications due to the previous operation history. The application of magnetic compression offers a new direction of minimally invasive therapy of complex biliary structure. This article summarizes the current situation of the therapy of complex biliary structure with magnetic compression and the existing obstacles. Key words: Biliary tract diseases; Cholangiopancreatography, endoscopic retrograde; Surgical procedures, minimally invasive; Magnetic compression technology

Modeling the relationship between the influencing factors and the multiple responses of coal‐like materials using Taguchi‐Gray correlation analysis for their utilization in gas seepage studies

AbstractCoal‐like sampling obtained through compression molding is an important application of powder compression molding technology in mining engineering. To obtain ideal coal‐like samples for the revelation of the seepage property of low‐permeability soft coals, gas seepage studies, which utilized the Taguchi method, were performed on coal‐like materials with different particle sizes, activated carbon weight, Portland cement weight, and forming pressure. The effect of a single factor on the fluid‐solid coupling property of coal‐like materials was analyzed. The results indicate that the permeability and axial stress curves that correlated with strain in the conventional triaxial tests can be divided into three clear phases, and that layered damage appears in all tested specimens. The stress‐permeability relationship model of coal‐like materials is proposed. The influence of process parameters on the strength and permeability of coal briquettes during gas seepage tests was experimentally investigated. The Taguchi method and gray correlation analysis were integrated to determine the best combination of input factors through the key indicator of the gray relational grade, which is required to satisfy multiple quality goals in gas seepage coal‐like materials. The contribution percentage of the input factors to the outputs was determined using analysis of variance; it indicated that coal particle size was the prominent influencing parameter followed by activated carbon, forming pressure, and Portland cement.