Bottom Segments Research Articles

Case studies of the load-bearing performance of shield tunnel segment with misaligned defects

The segment misalignment is a common defect in the segment installation of a shield tunnel construction, due to the complexity and uncertainty of its construction conditions. This raises a concerning about the safety of the segment lining for the shield tunnel. In this paper, the integrated numerical models with surrounding rock, peastone grouting and segment lining were built using three-dimensional finite element method, by introducing two kinds of misaligned defects of segments. One was the misalignment that elongated the horizontal axis of the transversal ring section of segment lining, another was the misalignment between adjacent rings of segments. To eliminate the impact of boundary on numerical results, seven rings of segments are built for the three-dimensional finite element models, and the middle ring is dealt with for the results analysis under V-class surrounding rock, including the circumferential stress of outer and inner layers of the segment, the contact stress on joint surface between segments, and the stress of locating pins between adjacent rings. Results indicate that the two kinds of misaligned defects create pronounced impact on tensile stress of segment at the bottom and the crown segments, respectively, which produces a greater tensile stress to increase cracking risk even abrupt fracture of segment. However, the misaligned defects have a slight impact on the contact stress and the locating pins stress. Therefore, attention should be paid to the cracking of bottom or crown segments in the segment lining of shield tunnel.

Numerical Modeling of Potential Large Wood Entrainment in Rivers: Application of Hybrid Modeling in the Inter‐Dam Reach of the Dyje River, Czechia

AbstractMobilization of large wood in river channels during floods represents a hazardous factor, augmenting flood risk and endangering infrastructures such as bridges, weirs, and reservoir dams. A hybrid modeling approach combining numerical models with field‐based surveys has been recently used to elucidate the processes of LW entrainment and deposition in rivers. We used two‐dimensional hydraulic modeling performed in HEC‐RAS to simulate LW entrainment in two valley bottom segments of the Dyje River, Czechia, where LW deposition is a significant hazard to the dam of the downstream Znojmo reservoir. We surveyed all LW pieces in the inundation area of the 2002 extreme (>Q100) flood and simulated their entrainment for eight flood scenarios (1–100‐year recurrence interval). We used the equations of Braudrick and Grant (2000, https://doi.org/10.1029/1999WR900290) to calculate the LW entrainment threshold; we introduced coefficient k accounting for the incomplete submersion of LW pieces resting on an inclined surface into the original equations. Four entrainment categories — stable, wetted stable, wetted buoyant, and wetted entrained — were defined, and the proportion of LW pieces in each category was calculated for the flood scenarios. We found marked differences in entrainment categories for respective flood scenarios between the two valley segments. These were attributed to the differences in pieces' dimensions, their spatial distribution within the inundation area, and valley‐bottom topography, which affects the hydraulic conditions for a given discharge. The presented approach enables the calculation of the LW quantity potentially mobilized by the flood of a certain magnitude indicating the degree of potential risk for the infrastructures located downstream.

Vertical patterns of leaf physiology and biofilm characteristics for Hydrilla verticillata in both single and mixed communities

Little is known about how community composition affects vertical patterns of leaf characteristics for submerged macrophytes in freshwater lakes. Here, after sampling Hydrilla verticillata in both single and mixed communities in shallow and deep areas in a shallow lake, we measured vertical patterns of leaf biofilm and physiology characteristics. Upper leaves of H. verticillata always had more attached abiotic biofilm matters, and all biofilm characteristics exhibited declining trends from top to bottom segments in deep areas. Moreover, the amount of attached biofilm matter in the mixed community was less than in the single community in shallow areas, but the reverse was true in deep areas. The vertical pattern of leaf physiology characteristics was obvious in the mixed community. In the shallow area, leaf pigment concentrations showed increasing trends with an increasing water depth, but the enzymatic specific activity of peroxidase (POD-ESA) was precisely the opposite. In the deep area, leaf chlorophyll concentrations were greatest in the leaves of bottom segments and lowest in top segments, while carotenoids and POD-ESA were greatest in the leaves of the middle segment-II. Light intensity and biofilm were found to play an important role in regulating the vertical patterns of photosynthetic pigments and POD-ESA. Our study highlighted the effect of community composition on the vertical pattern of leaf physiology and biofilm characteristics. HIGHLIGHTS: Biofilm characteristics always showed increasing trends with increasing water depth. Community composition changed the amount of attached biofilm matter. The vertical pattern of leaf physiology was more obvious in mixed communities. Light intensity and biofilm regulated the vertical pattern of leaf physiology.

Structural Behavior Analysis of UHPC Hybrid Tower for 3-MW Super Tall Wind Turbine Under Rated Wind Load

Based on the conceptual design of an advanced wind turbine tower system, use of ultra-high-performance cementitious composites material with compressive strength of 200 MPa (UHPC-200) is proposed to ensure high durability and ductility of the UHPC hybrid wind turbine tower. Key design parameters are proposed for the structural design of a 3-MW wind turbine. The material properties, mixing compositions, simplified constitutive relationship, and model parameters are outlined. Using nonlinear finite element analysis, the effects of wall thickness, wall thickness ratio, and prestressing tendon on the structural performance including the longitudinal stress field, lateral displacement, stress concentration at the transition zone between the middle and bottom segments are evaluated. Based on the stress-field analysis, the design limitation of the segmental wall thickness and its ratio is recommended. The numerical results show that the tower with the wall thickness ratio of 2:3 (i.e., thickness 200–300 mm) with prestressing tendons is an optimal design for the UHPC hybrid tower. The results of this study can be used as a reference for the engineering design of a new type of UHPC hybrid wind turbine tower.

The effects of a dividing line in a product assortment on perceived quantity, willingness to buy, and choice satisfaction

AbstractMany retailers use seemingly innocuous dividing lines to separate product alternatives on their websites or product catalogs. Although previous research on advertising design has focused on the impact of dividing lines on symbolic meanings or perceived categorization, the present research argues that, beyond symbolic or categorical functions, a dividing line can influence consumers' perceived quantity of the product alternatives displayed. Across 10 studies (including an eye‐tracking study and three additional studies reported in the Supporting Information Appendix), our results show that consumers perceive a smaller number of products displayed on a page when these products are separated by a dividing line compared to when they are not. This effect occurs because the dividing line separates the products into top versus bottom (or left vs. right) segments, such that participants' visual attention is largely drawn to the top (or the left) where their eyes first fixate. Consequently, participants tend to estimate the total number of items based on the subset they pay attention to. In addition, the effect is attenuated when participants' attention is directly drawn to the segment they have previously neglected and can hold regardless of line orientation. Finally, it can have several marketing outcomes, such as higher willingness to buy and lower post‐choice satisfaction.

Cracking feature and mechanical behavior of shield tunnel lining simulated by a phase-field modeling method based on spectral decomposition

Disturbed by the surrounding engineering construction, the shield tunnel lining may appear mixed-mode cracks such as segment cracking and joint crushing, which seriously damage its mechanical behaviors. To simulate the shield tunnel lining with mixed-mode cracks, a phase-field modeling method based on spectral decomposition is proposed, which unifies the critical energy release rate and crack-driving strain energy. The indoor full-scale tests are carried out to study the failure mechanism of the segment and joint. The phase-field modeling method is verified by the tests, and the influence of loading path on the cracking feature and mechanical behavior of the segment and joint are analyzed by the proposed numerical method. The test and numerical simulation indicate that the crack in the segment gradually develops from I-type crack (tensile crack) to Y-type crack (tensile-shear crack), and the joint is crushed due to local compression, and the crushed region expands gradually with the increase of the eccentricity. As the eccentricity decreases, the ultimate bearing capacity of the segment and joint is improved, while the ductility decreases. Then, the phase-field modeling method is extended to the stratum-structure model. As the surface load increases, the joints of the shield tunnel lining are crushed, and the top and bottom segments are cracked. Meanwhile, the bending moment is reduced due to the redistribution of internal forces caused by the segment cracking and joint crushing.

390 Characterisation of a Platelet Rich Fibrin Membrane and Formation of an Autologous Fibrin Mesh

Abstract Aim Platelet-rich fibrin (PRF) is a three-dimensional fibrin scaffold with associated platelets and leukocytes which releases high quantities of growth factors over a sustained period of time. PRF has shown promising clinical results in promoting wound healing and tissue regeneration. The aims of this feasibility study were to establish optimal spinning methods for production of PRF, to quantify the production of vascular endothelial growth factor (VEGF) by PRF and to explore new vehicles of clinical PRF delivery. Method Assessment of optimal production involved comparisons between Protocol 1 (EDTA bottle) and Protocol 2 (no additive) at three different centrifugation forces: 400g, 1000g and 1700g. VEGF production was analysed using ELISA with varied incubation periods and PRF plug segments. Novel methods for PRF delivery were explored using surgical sutures and a Zimmer® Skin Graft Mesher. Results Protocol 2 demonstrated shorter average time to blood draw (9.8s compared to 13.6s) and to centrifuge (25.5s compared to 33.1s) with a decreased range of values. All PRF segments exhibited a positive correlation between incubation time and amount of VEGF produced with the bottom segments producing on average more VEGF. A segment of the fibrin plug was successfully secured on a suture and meshed in a 1:1.5 ratio. Conclusions PRF production can be optimised using blood bottles with no additive and high centrifugation forces. VEGF production by PRF peaks at 120 hours with the bottom PRF segment exhibiting the highest rate of production. The first description of a PRF mesh enables new clinical applications.

Laminated Bamboo Board: A Sustainable Alternative to Timber Board for Building Construction

There is increased advocacy for low-carbon environment globally, necessitating the promotion of ecologically friendly building materials. The health and environmental hazards associated with conventional building material production, as well as the high cost on the economy for the importation of machinery for their production; the massive utilisation of wood resources for construction purposes, and its effect on climate change, necessitates the search for alternative construction materials. The purpose of this study is to examine the sustainability of a composite board made from Bambusa vulgaris for building construction. A 600 mm x 600 mm wall and floor-board comprising three sample units for different thicknesses; 10 mm, 20 mm and 40 mm were produced from each segment; top, middle, and bottom, of the bamboo culm with approximately 8-10 mm laminate. The results revealed average compressive strength values for the bottom, middle, and top bamboo segments of 31.39 N/mm2, 29.38 N/mm2, and 24.99 N/mm2, respectively. The highest impact bending strength of 33.66 N/mm2 and 27.94 N/mm2 occurs at the middle and top segments of the bamboo species respectively. Modulus of Rupture decreases from the bottom to the top segment of the bamboo species with values of 76.43 N/mm2, 62.33 N/mm2, and 56.70 N/mm2, respectively. Furthermore, thermal properties indicate that it is a good material for interior walls, floors, and ceiling finishes. These findings have far-reaching implications for practice and economic development; regarding reduction in the cost of materials, and hence affordability for low-income housing; overall safety of the environment; and employment opportunities for Nigerian youths along the construction value chain.

How much economic inequality is fair in liberal democracies? The approach of proportional justice

The article argues that the possibility of an unlimited gap in income and wealth between the top and bottom segments of society is incompatible with a democratic commitment to political equality. The first section outlines why current distributive and relational approaches are unable to adequately address this problem. The second and third sections introduce the notion of material domination and argue that the only remedy against it is the containment of economic inequality within a certain proportion, expressed in terms of ratios between the material resources of the best-off and the worst-off. The fourth section spells out the constraints that any definition of these ratios should satisfy and shows, through a case study based on the contemporary United States, that an approximate, yet non-arbitrary definition is within reach. The fifth and final section rebuts some predictable objections to this approach.

Vertical patterns of leaf physiology and biofilm characteristics for submerged macrophytes in a shallow subtropical lake

Little is known about vertical patterns of leaf characteristics for submerged macrophytes in freshwater ecosystems. Here, after sampling Ceratophyllum demersum and Hydrilla verticillata in deep (3.8 m) and shallow areas (1.0 m) in a shallow subtropical lake, we cut the individuals into segments along the vertical direction, and measured leaf biofilm and physiology characteristics. In the deep area, leaf pigment concentrations showed declining trends with an increasing water depth, but the enzymatic specific activity of peroxidase (POD-ESA) was precisely the opposite. Moreover, the amount of attached biofilm matter and epiphyte biomass were greatest on leaves of upper middle segments, and lowest on bottom segments. In the shallow area, bottom leaves of C. demersum had more attached biofilm matter and epiphyte biomass, but the opposite was true for H. verticillata. Additionally, leaf chlorophyll-a concentration was higher on the bottom segments for H. verticillata, and C. demersum had a higher POD-ESA in bottom leaves. Our analysis found that vertical pattern of leaf physiology was closely related to light intensity, and biofilms played an auxiliary role. Our study highlighted vertical patterns of leaf biofilm and physiology for submerged macrophytes, and suggested that such patterns are generally species-specific, especially in shallow areas.

Nonlinear dynamic response analysis of marine risers under non-uniform combined unsteady flows

Considering the top-end platform surge induced by periodic wave, the encountered flow field of marine risers under the actual marine environment is approximate to a combined sheared and sheared-oscillatory flow, which is non-uniform in both time and spatial domains. A published time domain force-decomposition model is proposed to predict the riser's nonlinear dynamic response under non-uniform combined unsteady flows. A 90 m flexible riser is chosen as the simulated object, and a large amount of the combined flow cases with different oscillation periods and combined ratios are designed. With the fundamental study on a steady sheared flow case, the structural dynamic response characteristics under non-uniform combined flows are investigated systematically. The overall dynamic response presents travel wave pattern, and the high-frequency response is easier to be excited for the riser's top and bottom segments. Some time-sharing response characteristics like amplitude modulation, frequency transition and mode jumps are captured, and they are affected by the flow field parameters significantly. Under the long oscillation period cases, the intermittent dynamic response follows the accordant periodicity with the current velocity. While under the short oscillation period cases, the unstable structural vibration occurs persistently without clear regularity. The combined ratio also influences the RMS displacement, excited frequency bandwidth and travel wave propagation velocity evidently. Associated with VIV mechanism analysis, the individual response characteristics under different flow field parameter combinations are explained reasonably.

Application of globally available, coarse‐resolution digital elevation models for delineating valley bottom segments of varying length across a catchment

AbstractThe worldwide availability of digital elevation models (DEMs) has enabled rapid (semi‐)automated mapping of earth surface landforms. In this paper, we first present an approach for delineating valley bottom extent across a large catchment using only publicly available, coarse‐resolution DEM input. We assess the sensitivity of our results to variable DEM resolution and find that coarse‐resolution datasets (90 m resolution) provide superior results. We also find that LiDAR‐derived DEMs produce more realistic results than satellite‐derived DEMs across the full range of topographic settings tested. Satellite‐derived DEMs perform more effectively in moderate topographic settings, but fail to capture the subtleties of valley bottom extent in mild gradient, low‐lying topography and in narrow headwater reaches. Second, we present a semi‐automated technique within ArcGIS for delineating valley bottom segments using DEM‐derived network scale metrics of valley bottom width and slope. We use an unsupervised machine‐learning technique based on the k‐means clustering algorithm to solve a conundrum in GIS‐based geomorphic analysis of rivers: the delineation of valley bottom segments of variable length. The delineation of valley bottom segments provides a coarse‐scale entry point into automated geomorphic analysis and characterization of river systems. © 2020 John Wiley & Sons, Ltd.

Genome-Wide Mapping of Loci Associated With Resistance to Clubroot in Brassica napus ssp. napobrassica (Rutabaga) Accessions From Nordic Countries.

Rutabaga [Brassica napus ssp. napobrassica (L.) Hanelt] is reported to be an excellent source of clubroot (Plasmodiophora brassicae) resistance genes. In this study, 124 rutabaga accessions from the Nordic countries (Norway, Sweden, Finland, Denmark, and Iceland) were evaluated for their reaction to five single-spore isolates representing P. brassicae pathotypes 2F, 3H, 5I, 6M, and 8N and 12 field isolates representing pathotypes 2B, 3A, 3O, 5C, 5G, 5K, 5L, 5X (two isolates, L-G2 and L-G3), 8E, 8J, and 8P. The accessions were also genotyped using a 15K Brassica SNP array and 60 PCR-based primers linked to previously identified clubroot resistance genes. Six thousand eight hundred sixty-one SNP markers were retained after filtering with TASSEL 5.0, and used to evaluate four general linear models (GLM) and four mixed linear models (MLM). The PCA + K and Q + K MLM models gave the minimal deviance of the observed from the expected distribution in quantile-quantile plots, and hence were used for SNP-clubroot association analyses. In addition, 108 alleles derived from the PCR-based markers and the phenotypic data were analyzed with the PCA + K model. Forty-five SNPs and four PCR-based markers were identified to be associated strongly with resistance to isolates representing 13 pathotypes (2F, 3H, 5I, 6M, 8N, 2B, 3A, 3O, 5C, 5G, 5K, 5L, and 8P). These markers revealed the top and bottom segments of rutabaga chromosome A03 and the middle segment of chromosome A08 as genomic hotspots associated with resistance to the different P. brassicae pathotypes.

Going up

Nordic researchers unveil their novel InAs/InGaAs nanowire MOSFETs on Si, which exhibit high-frequency gains for use in a gate-last configuration. The architecture of the device enables highly asymmetric capacitances, increasing its power gain. The authors' device shows a transit frequency (fT) of 120 GHz and maximum frequency (fmax) of 130 GHz, from a channel length (Lg) of 120 nm, demonstrating the state-of-the-art performance of their architecture. Moore's law states that the number of transistors on a microchip doubles roughly every 2 years, and has been the driving force behind the development of electrical devices for the past few decades. Silicon-based metal-oxide semiconductor field effect transitors (MOSFETs) in particular have become a rapidly developing area of research due to their high degree of scalability in digital applications. MOSFETs combining group 3 and group 5 elements (so called ‘III-V’ MOSFETs) in particular have performed beyond other transistor architectures in the realms of transconductance and the on-current. Difference between gate-last and gate-first fabrications SEM picture after gate-finger fabrication For higher frequency transistors, the inability to scale high-electron-mobility transistors (HEMTs) due to an insufficient gate-barrier has caused development of fT to stagnate around 700 GHz. The authors propose that better scaling in III-V MOSFETs could hold the key to surpassing HEMTs in high-frequency applications. Indeed, it has been shown that a number of planar MOSFETs recently have displayed fT values in the region of 400 GHz. The authors in their publication in Electronics Letters present the prospect of verical III-V nanowires for use in high-frequency devices. The nanowires are grown using a technique known as VLS, or ‘vapor-liquid-solid’ growth. This scheme is more easily integrated on a Silicon substrate, and also allows engineering of the band-gap properties of the semiconductor, giving rise to improved intrinsic voltage gain and a higher breakdown voltage without the deterioration of other performance metrics. The growth of vertical nanowire MOSFETs can be generally divided into two processes: gate-last and gate-first processes. Gate-first processes are generally less desirable, as they produce thin nanowire contacts and leave ungated regions at the top of the nanowire, which increases the access resistance at this point. Gate-last devices form a recessed gate and add metal to the sidewalls of the nanowire, reducing the access resistance. The gate-last MOSFETs produced by the authors here are based on InAs/In0.4Ga0.6As heterostructure nanowires which have been fabricated on a Si{111} substrate. The wire can be considered in 3 parts: a bottom segment made of highly-doped InAs, a middle segment which is unintentionally doped as the wire transitions from InAs to InGaAs and a top segment which is highly doped InGaAs. The middle and bottom segments are each 100 nm in length, whilst the top segment measures 300 nm in length. The gate connects the bottom and middle segments. The authors provide a comparison with a number of other MOSFET devices produced on Silicon. Their device shows comparable performance with the referenced works, even before the full optimisation of their device. Such optimisations will take the form of further scaling of the structure to reduce capacitances. Authors note that their device should be scalable all the way down to 25 nm. The work presented in Electronics Letters could prove to be a key piece of the puzzle when dealing with the continued minimisation of electronic circuits, with early results showing that the proposed architecture is capable of keeping up with current state-of-the-art devices.

Rapid Processing of Abandoned Oil Palm Trunks into Sugars and Organic Acids by Sub-Critical Water

Abandoned oil palm trunk (OPT) is among the most abundant left-over biomass in Malaysia and is allowed to decompose naturally in the field. However, the recycling of OPT is less considered although OPT is a bioresource that has a high potential for conversion into value-added products. In this study, waste OPT was rapidly converted by hydrolysis using subcritical water (sub-CW). This work is the first attempt to explore the utilization of waste OPT based on the differences in moisture, cellulose and hemicellulose contents in the top and bottom segments, and from various ages of the waste OPT. 21- and 35-year-old OPTs were divided into top and bottom sections. The OPTs was subjected to sub-CW at a heating rate of 3.8 °C/s at various temperatures and times. The 21-year-old OPT was superior to the 35-year-old OPT for conversion into sugar and organic acid. The yield of the total sugar was between 0.41 and 0.77 kg/kg-OPT in the bottom and top sections. The excellent correlation between the sugar yield and sub-CW ion product (Kw) signified that the sub-CW facilitated the hydrolysis of hemicellulose and cellulose in the OPT. In the bottom segment, fructose had a higher yield, while in the top part glucose was dominant. Sugar degradation from the sub-CW treatment of OPT produced 0.2 kg/kg-OPT organic acids. The treatment of OPT using sub-CW showed promising results in producing sugars and organic acids.

Investigating tension in overhead high voltage power transmission line using finite element method

Transmission line failure is a serious problem in developing countries. The major cause of high voltage overhead transmission line failure in power system is prolonged excessive current. The determination of line segments where high tension is generated due to prolonged excessive current under the different arrangements of line spacing and current carrying conditions can lead us to analyze high tension zones for efficient design of transmission lines. In this context, the mechanical tension on an overhead high voltage electrical power transmission line resulting from excessive or normal currents was computed using Finite Element Method. Multiple segments of a long transmission line with symmetrical and unsymmetrical spacing under accidental and normal line current are examined. Therein, the line segments with high tension are determined. Maximum integrated tension is found in middle segments of both symmetrical and unsymmetrical spaced transmission line. While, maximum per unit tension is found in initial and bottom segments. However, variation in magnitude is found for symmetrical and unsymmetrical spacing. The present study may provide technical guidance to the transmission line design engineers and technicians regarding the risk and solutions related to electrical power transmission line systems.

Experimental and Numerical Investigations on Seismic Behavior of Prefabricated Bridge Columns with UHPFRC Bottom Segments

Experimental and Numerical Investigations on Seismic Behavior of Prefabricated Bridge Columns with UHPFRC Bottom Segments

The response of precast concrete segmental columns subjected to near base impact

Precast concrete segmental column has attracted many attentions for the past decades due to its unique features especially in improving the construction quality and efficiency. However, the performance of precast segmental column under lateral impact loading has been less studied. Our previous studies performed laboratory pendulum impact tests on scaled segmental columns to investigate their behaviours when impacted at mid-span of the column. This article studies the response of segmental column when impacted near the column base, which generates different response modes and failure mechanisms compared to the columns subjected to the mid-span impact. Lateral impacts are applied either to segmental joint between the two bottom segments or directly onto the centre of the base concrete segment. A detailed three-dimensional numerical model is created and validated with laboratory impact testing results on scaled segmental columns. A full-scale 3-m tall segmental column is then numerically built to study the behaviour under near base impact. The column damage and failure modes are analysed. The influences of prestress level in the post-tensioning tendon and concrete strength on the performance of segmental column subjected to near base impacts are investigated through numerical simulations.

Exploring the Impact of Financial Development on Inequality: Evidence from Three Asian Countries

The broad objective of the present study is to investigate the impact of financial development along with some other variables namely GDP per capita, inflation rate, human capital, and trade openness for three developing Asian countries- Bangladesh, India and Pakistan. Annual time series data during the period 1980-2014 have been used for empirical investigation. After employing appropriate tests and estimation techniques, it is found that the financial development is statistically insignificant for all three countries, it implies that yet these developing countries are not efficiently allocating domestic private credit to poor segments of population. The results also reveal that inflation impedes income inequality for Bangladesh and India. GDP growth rate is insignificant for India and Pakistan however it is significant for Bangladesh having statistically positive relationship with income inequality. It means that GDP growth rate is linked with growth of income of elite class rather than bottom segments of population. National income improves inequality for Bangladesh but have insignificant affect on income inequality for India and Pakistan. Similarly, trade openness is insignificant for India and Pakistan, however it is significant for Bangladesh having statistically positive relationship with income inequality, which indicates that there is increasing unemployment in these countries due to lesser employment opportunities for skilled and unskilled labour. Empirical results of human capital shows insignificancy for India and Pakistan where as it is significant for Bangladesh; hence revealing that these countries failed to optimally utilize their resources in educational sector.

Health Care Cost Analyses for Exploring Cost Savings Opportunities in Older Patients: Longitudinal Retrospective Study.

BackgroundHalf of Medicare reimbursement goes toward caring for the top 5% of the most expensive patients. However, little is known about these patients prior to reaching the top or how their costs change annually. To address these gaps, we analyzed patient flow and associated health care cost trends over 5 years.ObjectiveTo evaluate the cost of health care utilization in older patients by analyzing changes in their long-term expenditures.MethodsThis was a retrospective, longitudinal, multicenter study to evaluate health care costs of 2643 older patients from 2011 to 2015. All patients had at least one episode of home health care during the study period and used a personal emergency response service (PERS) at home for any length of time during the observation period. We segmented all patients into top (5%), middle (6%-50%), and bottom (51%-100%) segments by their annual expenditures and built cost pyramids based thereon. The longitudinal health care expenditure trends of the complete study population and each segment were assessed by linear regression models. Patient flows throughout the segments of the cost acuity pyramids from year to year were modeled by Markov chains.ResultsTotal health care costs of the study population nearly doubled from US $17.7M in 2011 to US $33.0M in 2015 with an expected annual cost increase of US $3.6M (P=.003). This growth was primarily driven by a significantly higher cost increases in the middle segment (US $2.3M, P=.003). The expected annual cost increases in the top and bottom segments were US $1.2M (P=.008) and US $0.1M (P=.004), respectively. Patient and cost flow analyses showed that 18% of patients moved up the cost acuity pyramid yearly, and their costs increased by 672%. This was in contrast to 22% of patients that moved down with a cost decrease of 86%. The remaining 60% of patients stayed in the same segment from year to year, though their costs also increased by 18%.ConclusionsAlthough many health care organizations target intensive and costly interventions to their most expensive patients, this analysis unveiled potential cost savings opportunities by managing the patients in the lower cost segments that are at risk of moving up the cost acuity pyramid. To achieve this, data analytics integrating longitudinal data from electronic health records and home monitoring devices may help health care organizations optimize resources by enabling clinicians to proactively manage patients in their home or community environments beyond institutional settings and 30- and 60-day telehealth services.