Multiple Regeneration Research Articles

Enhanced DOC removal using anion and cation ion exchange resins

Hardness and DOC removal in a single ion exchange unit operation allows for less infrastructure, is advantageous for process operation and depending on the water source, could enhance anion exchange resin removal of dissolved organic carbon (DOC). Simultaneous application of cationic (Plus) and anionic (MIEX) ion exchange resin in a single contact vessel was tested at pilot and bench scales, under multiple regeneration cycles. Hardness removal correlated with theoretical predictions; where measured hardness was between 88 and 98% of the predicted value. Comparing bench scale DOC removal of solely treating water with MIEX compared to Plus and MIEX treated water showed an enhanced DOC removal, where removal was increased from 0.5 to 1.25 mg/L for the simultaneous resin application compared to solely applying MIEX resin. A full scale MIEX treatment plant (14.5 MGD) reduced raw water DOC from 13.7 mg/L to 4.90 mg/L in the treated effluent at a bed volume (BV) treatment rate of 800, where a parallel operation of a simultaneous MIEX and Plus resin pilot (10 gpm) measured effluent DOC concentrations of no greater than 3.4 mg/L, even at bed volumes of treatment 37.5% greater than the full scale plant. MIEX effluent compared to simultaneous Plus and MIEX effluent resulted in differences in fluorescence intensity that correlated to decreases in DOC concentration. The simultaneous treatment of Plus and MIEX resin produced water with predominantly microbial character, indicating the enhanced DOC removal was principally due to increased removal of terrestrially derived organic matter. The addition of Plus resin to a process train with MIEX resin allows for one treatment process to remove both DOC and hardness, where a single brine waste stream can be sent to sewer at a full-scale plant, completely removing lime chemical addition and sludge waste disposal for precipitative softening processes.

Systems analysis of non-parenchymal cell modulation of liver repair across multiple regeneration modes.

BackgroundA hallmark of chronic liver disease is the impairment of the liver’s innate regenerative ability. In this work we use a computational approach to unravel the principles underlying control of liver repair following an acute physiological challenge. MethodsWe used a mathematical model of inter- and intra-cellular interactions during liver regeneration to infer key molecular factors underlying the dysregulation of multiple regeneration modes, including delayed, suppressed, and enhanced regeneration. We used model analysis techniques to identify organizational principles governing the cellular regulation of liver regeneration. We fit our model to several published data sets of deficient regeneration in rats and healthy regeneration in humans, rats, and mice to predict differences in molecular regulation in disease states and across species. ResultsAnalysis of the computational model pointed to an important balance involving inflammatory signals and growth factors, largely produced by Kupffer cells and hepatic stellate cells, respectively. Our model analysis results also indicated an organizational principle of molecular regulation whereby production rate of molecules acted to induce coarse-grained control of signaling levels while degradation rate acted to induce fine-tuning control. We used this computational framework to investigate hypotheses concerning molecular regulation of regeneration across species and in several chronic disease states in rats, including fructose-induced steatohepatitis, alcoholic steatohepatitis, toxin-induced cirrhosis, and toxin-induced diabetes. Our results indicate that altered non-parenchymal cell activation is sufficient to explain deficient regeneration caused by multiple disease states. We also investigated liver regeneration across mammalian species. Our results suggest that non-invasive measures of liver regeneration taken at 30 days following resection could differentiate between several hypotheses about how human liver regeneration differs from rat regeneration. ConclusionsOverall, our results provide a new computational platform integrating a wide range of experimental information, with broader utility in exploring the dynamic patterns of liver regeneration across species and over multiple chronic diseases.Electronic supplementary materialThe online version of this article (doi:10.1186/s12918-015-0220-9) contains supplementary material, which is available to authorized users.

California forests show early indications of both range shifts and local persistence under climate change

AbstractAimForest regeneration data provide an early signal of the persistence and migration of tree species, so we investigated whether species shifts due to climate change exhibit a common signal of response or whether changes vary by species.LocationCalifornia Floristic Province, United States; mediterranean biome.MethodsWe related Forest Inventory and Analysis (FIA) data from 2000−07 for 13 tree species to high‐resolution climate and geographical data. Using methods from invasion ecology, we derived indices of species‐specific regeneration overlap and central tendency change (range‐wide global indicators) based on kernel density estimation of presence and absence of regeneration. We then built regeneration surfaces to identify areas of occurrence of high regeneration (regeneration hotspots, local indicators) in both geographical and climate space for 13 common tree species.ResultsDifferences between presence and absence of regeneration in forests varied in magnitude across species, with little evidence that tree regeneration is shifting to higher latitudes and elevations, the expected geographical fingerprint of climate change. We also identified potential topographic mediators of regeneration dynamics. Multiple regeneration hotspots were found for many species, suggesting the influence of non‐climatic factors on regeneration. Differences between the presence and absence of regeneration in geographic and climate spaces were not always congruent, suggesting that shifting climate space and range area are not entirely coupled.Main conclusionsThe distributions of regeneration in Californian forests show diverse signals, not always tracking the higher latitudinal–elevation fingerprint of climate change. Local regeneration hotspots are common in our analysis, suggesting spatially varying persistence of forest linked to natural and anthropogenic disturbances. Our results emphasize that projections of tree range shifts in the context of climate change should consider the variation of regeneration drivers within species ranges, beyond the overall climate signal.

Late Pleistocene sea-level changes recorded in tidal and fluvial deposits from Itaubal Formation, onshore portion of the Foz do Amazonas Basin, Brazil

ABSTRACTThe Pleistocene deposits exposed in the Amapá Coastal Plain (onshore portion of the Foz do Amazonas Basin, northeastern South America) were previously interpreted as Miocene in age. In this work, they were named as "Itaubal Formation" and were included in the quaternary coastal history of Amazonia. The study, through facies and stratigraphic analyses in combination with optically stimulated luminescence (single and multiple aliquot regeneration), allowed interpreting this unit as Late Pleistocene tidal and fluvial deposits. The Itaubal Formation, which unconformably overlies strongly weathered basement rocks of the Guianas Shield, was subdivided into two progradational units, separated by an unconformity related to sea-level fall, here named as Lower and Upper Units. The Lower Unit yielded ages between 120,600 (± 12,000) and 70,850 (± 6,700) years BP and consists of subtidal flat, tide-influenced meandering stream and floodplain deposits, during highstand conditions. The Upper Unit spans between 69,150 (± 7,200) and 58,150 (± 6,800) years BP and is characterized by braided fluvial deposits incised in the Lower Unit, related to base-level fall; lowstand conditions remained until 23,500 (± 3,000) years BP. The studied region was likely exposed during the Last Glacial Maximum and then during Holocene, covered by tidal deposits influenced by the Amazon River.

Epoxyeicosatrienoic acids enhance embryonic haematopoiesis and adult marrow engraftment.

Haematopoietic stem and progenitor cell (HSPC) transplant is a widely used treatment for life-threatening conditions including leukemia; however, the molecular mechanisms regulating HSPC engraftment of the recipient niche remain incompletely understood. Here, we developed a competitive HSPC transplant method in adult zebrafish, using in vivo imaging as a non-invasive readout. We used this system to conduct a chemical screen and identified epoxyeicosatrienoic acids (EET) as a family of lipids1,2 that enhance HSPC engraftment. EETs’ pro-haematopoietic effects were conserved in the developing zebrafish embryo, where 11,12-EET promoted HSPC specification by activating a unique AP-1/runx1 transcription program autonomous to the haemogenic endothelium. This effect required the activation of the PI3K pathway, specifically PI3Kγ. In adult HSPCs, 11,12-EET induced transcriptional programs, including AP-1 activation, which modulate multiple cellular processes, such as migration, to promote engraftment. Finally, we demonstrated that the EET effects on enhancing HSPC homing and engraftment are conserved in mammals. Our study established a novel method to explore the molecular mechanisms of HSPC engraftment, and discovered a previously unrecognized, evolutionarily conserved pathway regulating multiple haematopoietic generation and regeneration processes. EETs may have clinical application in marrow or cord blood transplantation.

Removal of natural organic matter (NOM) by ion exchange from surface water for drinking water production: a pilot-scale study

Natural organic matter (NOM) in drinking water causes esthetic concerns such as odor, taste, and color and is responsible for the disinfection byproducts formation during drinking water production. The goal of this study was to determine the efficiency of macroporous polyacrylic ion exchange resins for the removal of NOM as a function of empty bed contact time (EBCT), bed expansion, and regeneration procedure. Two resins were examined: the coarse Purolite®PPA860S and the fine Purofine®PFA860 resin. The tests showed that both resins are suitable for NOM removal. The reduction in particle size (beads of the fine resin were 18% smaller than those of the coarse one) of the fine resin had little effect on NOM removal, although the exchange capacity of the fine resin after regeneration was 12% higher than that of the coarse resin after multiple regenerations. The influence of SO42- (due to the re-use of the regenerating solution) was examined on the basis of a regeneration solution with only SO42-. The test results showed no reduction in NOM removal during prolonged operation. Finally, it was concluded that the EBCT can be significantly reduced as increasing the flow velocity from 15 to 20 m/h did not result in a significant reduction in NOM removal efficiency.

Adsorptive removal of carbon dioxide using polyethyleneimine loaded glass fiber in a fixed bed

Low-cost glass fiber (GF) was modified by loading polyethyleneimine (PEI) using a physical impregnation method and applied as an adsorbent for CO2 capture. The structure and morphology of the PEI-loaded GF were characterized by thermogravimetic analyzer (TGA), fourier transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM). The PEI-loaded GF possessed a core–shell structure. The CO2 dynamic adsorption–desorption performances were investigated in a PEI-loaded GF fixed bed. The effects of PEI loading ratio, adsorption temperature, relative humidity (RH), flow rate and bed depth (H/D) ratio were examined, and the maximal dynamic CO2 adsorption capacity was 60.04 mg g−1 with a PEI/GF ratio of 0.70 g g−1. In addition, the PEI-loaded GF was regenerated with only a slight decrease in the adsorption capacity after multiple regenerations using an optimum regeneration temperature of 100 °C. The results suggest that the PEI-loaded GF can be used as an economical adsorbent system for CO2 capture.

Desorption of octanethiol from gold electrode surface during its electrochemical cleaning

The potentialities of electrochemical method of removal of adsorbed octanethiol layer from gold electrode surface are considered. The dependence of a degree of gold macro- and microelectrode cleaning on the electrolyte composition, potential cycling range, and the number of cycles is studied. It is shown that the commonly used method of cleaning by multiple potential cycling in the perchloric acid solution in the potential range from 0 to 1400 mV (SCE) is not sufficiently efficient. Cycling in the water-ethanol solution of perchloric acid promotes the octanethiol desorption and leads to the complete regeneration of surface even after 6–8 cycles. This is evidenced by comparing with the voltammograms, which were obtained on pure Au surface in 4 mM potassium ferri-ferrocyanide and 0.1 M HClO4 solutions. A range of ethanol concentrations, which provides the highest degree of gold surface cleaning, is determined. The electrochemical method of cleaning by using water-ethanol solution of perchloric acid enables one to perform multiple electrode regeneration without destruction of thin gold layer (for example, in the quartz microbalance), which takes place in the case of chemical regeneration in the “piranha” solution based on sulfuric acid and hydrogen peroxide.

Regeneration of magnetic biochar derived from eucalyptus leaf residue for lead(II) removal

Regeneration of Pb-loaded magnetic biochar prepared with eucalypts leaf residue was studied by using EDTA-2Na as a regenerant. The desorption efficiency was found to be 84.1% in 120min with iron leaching amount of 1.1mgg−1. Higher SBET and pore volume were observed in regenerated magnetic biochars and no significant band shifts occurred in FTIR spectra during 6 regeneration cycles. The decrease of Pb(II) adsorption capacity (from 52.4 to 41.5mgg−1) was only found in the first regeneration cycle. Magnetic separation performance of adsorbents was not significantly affected by multiple regeneration cycles.

H2 generation from thermochemical water-splitting using yttria stabilized NiFe2O4 core-shell nanoparticles

This investigation reports synthesis of core-shell NiFe2O4/Y2O3 nanoparticles by sol-gel technique and their H2 volume generation ability via thermochemical water-splitting reaction at 900 °C–1100 °C. Thermochemical water-splitting process involves a cyclic operation of a low-temperature water-splitting step and relatively high temperature regeneration step using redox materials. Because of the cyclic nature of the process, the redox materials undergo thermal fatigue leading to grain growth or sintering, consequently, steady H2 production is not realized in multiple thermochemical cycles. In this study, attempts were made to achieve steady H2 volume generation in multiple thermochemical cycles using core-shell nanoparticles, which were synthesized using precursors such as NiCl2, FeCl2, and YCl3, and pluronic P123 surfactant template. H2 volume generated by NiFe2O4/Y2O3 core-shell nanoparticles was found to be relatively stable over multiple thermochemical cycles. Contrasting to this, the H2 volume generation was found to decrease continuously over multiple thermochemical cycles using NiFe2O4 nanoparticles as well as NiFe2O4/Y2O3 powdered mixture of nanoparticles. The transient O2 profiles were also compared for both the core-shell nanoparticles and powdered mixture during multiple regeneration steps. Detailed transmission electron microscopy (TEM) analysis clearly provided evidence of core-shell morphology with NiFe2O4 core encapsulated by Y2O3 shell. The grain size and morphological properties of as-prepared nanoparticles were compared with the nanoparticles obtained after thermochemical water-splitting reaction using powdered X-ray diffraction, and scanning electron microscopy.

Modeling water and hydrogen networks with partitioning regeneration units

Strict environment regulations in chemical and refinery industries lead to minimize resource consumption by designing utility networks within industrial process plants. The present study proposed a superstructure based optimization model for the synthesis of water and hydrogen networks with partitioning regenerators without mixing the regenerated sources. This method determines the number of partitioning regenerators needed for the regeneration of the sources. The number of the regenerators is based on the number of sources required to be treated for recovery. Each source is regenerated in an individual partitioning regenerator. Multiple regeneration systems can be employed to achieve minimum flowrate and costs. The formulation is linear in the regenerator balance equations. The optimized model is applied for two systems, partitioning regeneration systems of the fixed outlet impurity concentration and partitioning regeneration systems of the fixed impurity load removal ratio (RR) for water and hydrogen networks. Several case studies from the literature are solved to illustrate the ease and applicability of the proposed method.

One-Step Process for the Production of BTEX and LPG-like fuel from Pentanediol

We report on a one-step process to produce value-added organic chemicals via deoxygenation of pentanediol (PeD) over HZSM-5 at temperatures between 325 and 450 °C and atmospheric pressure. The conversion efficiency of PeD to petroleum gas (C2–C5) and aromatics (benzene, toluene, ethylbenzene, and xylenes) reached up to 94% (carbon yield); we observed minimal CO, CO2, and coke production. Furthermore, the carbon yield to the desired products remained near 91.5% with a steady product distribution for 40 h. No severe degradation of catalytic activity of HZSM-5 due to the presence of water in the product stream was observed after multiple regenerations. The catalytic process represents a valuable step toward displacing petroleum-based chemicals.

Adsorption characteristics of propan-2-ol vapours on activated carbon Sorbonorit 4 in electrothermal temperature swing adsorption process

Adsorption characteristics of propan-2-ol on Sorbonorit 4 activated carbon were determined using the breakthrough curve tests in a cyclic electrothermal temperature swing adsorption process. Maximum adsorption capacity, breakthrough time, throughput ratio and length of unused bed were also evaluated. As a result of multiple regeneration, the adsorption capacity of Sorbonorit 4 increased. Electrothermally-induced changes in the internal structure of Sorbonorit 4 and in the chemical composition of its surface were assessed based on adsorption equilibrium measurements by the gravimetric method and X-ray photoelectron spectroscopy (XPS). Three samples of virgin, direct resistively heated and electrothermally regenerated Sorbonorit 4 were used. The structural characteristics of activated carbon show that that fresh and direct resistive heated Sorbonorit 4 has a bimodal structure. Regenerated activated carbon contains one fraction of micropores. XPS analysis revealed that the same hydroxyl, carbonyl and carboxyl groups were found on the surface of all Sorbonorit 4 samples, albeit in different volume ratios. Regenerated Sorbonorit 4 has higher adsorption capacity than pure adsorbent while resistively heated Sorbonorit 4 displays lower adsorption efficiency.

Electrospun scaffolds for multiple tissues regeneration in vivo through topography dependent induction of lineage specific differentiation

Physical topographic cues from various substrata have been shown to exert profound effects on the growth and differentiation of stem cells due to their niche-mimicking features. However, the biological function of different topographic materials utilized as bio-scaffolds in vivo have not been rigorously characterized. This study investigated the divergent differentiation pathways of mesenchymal stem cells (MSCs) and neo-tissue formation trigged by aligned and randomly-oriented fibrous scaffolds, both in vitro and in vivo. The aligned group was observed to form more mature tendon-like tissue in the Achilles tendon injury model, as evidenced by histological scoring and collagen I immunohistochemical staining data. In contrast, the randomly-oriented group exhibited much chondrogenesis and subsequent bone tissue formation through ossification. Additionally, X-ray imaging and osteocalcin immunohistochemical staining also demonstrated that osteogenesis in vivo is driven by randomly oriented topography. Furthermore, MSCs on the aligned substrate exhibited tenocyte-like morphology and enhanced tenogenic differentiation compared to cells grown on randomly-oriented scaffold. qRT-PCR analysis of osteogenic marker genes and alkaline phosphatase (ALP) staining demonstrated that MSCs cultured on randomly-oriented fiber scaffolds displayed enhanced osteogenic differentiation compared with cells cultured on aligned fiber scaffolds. Finally, it was demonstrated that cytoskeletal tension release abrogated the divergent differentiation pathways on different substrate topography. Collectively, these findings illustrate the relationship between topographic cues of the scaffold and their inductive role in tissue regeneration; thus providing an insight into future development of smart functionalized bio-scaffold design and its application in tissue engineering.

Effect of Growth Additives, Media strength and Sucrose Concentration onin vitroPlant Regeneration from Nodal Explants ofGymnema sylvestre

Gymnema sylvestre R.Br. of Asclepiadaceae family is an important endangered medicinal plant having potent anti-diabetic property. Nodal explants were inoculated in half and full MS medium strength with different sucrose concentrations. Plant growth regulators were used at various concentrations (0.2, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0 mg/l). Almost at every concentration shoot primordia were seen within 8–10 days of inoculation. Gymnema sylvestre showed better multiple shooting and regeneration of explants in full strength MS media with 3% sucrose in comparison to ½ MS media. Both BAP and Kinetin in combination with IBA showed better growth rate in terms of number of shoot, length of shoots and number of leaves. 0.5 mg/l BAP, 0.5 mg/l Kinetin and 3.0 mg/l IBA produced maximum number of shoots (7.00±0.70), maximum length of shoots (6.57±0.75 cm) and maximum number of leaves (20.25±1.54). Gibberellic acid at 1.5 mg/l showed most promoting effect on the shoot elongation. Growth additives like adenine sulphate and maltose improved the quality and quantity of in vitro raised shoots from explants. Both ½ and ¼ MS media performed better for rooting in comparison to full strength MS media. In vitro raised plants were hardened and acclimatized in the potting mixture of sterilized perlite, garden soil and sand (1:1:1) in the culture room. After hardening, they were established in the polyhouse and later transferred in the field where they showed 70% survival rate.

Effect of Pt and Gd on coke formation and regeneration during JP-8 cracking over ZSM-5 catalysts

Pt and Gd loaded ZSM-5 catalysts were synthesized by ion exchange method to investigate the effect of metal promoters on catalyst activity, coking and regeneration during military aviation fuel (JP-8) cracking into petroleum gas (PG) at 723K. Multiple cracking and regeneration cycles were performed over the ZSM-5 based catalysts and their crystalline structure, oxidation profile, coke band and acidity were characterized. It was revealed that addition of Gd metal to the ZSM-5 catalyst prevented formation of complex aromatic coke and increased the number of Lewis acid sites, while Pt promoted ZSM-5 catalyst showed a decrease in the coke oxidation temperature. The effect of Pt and Gd promoters enhanced the coke burn-off ability, formed hydrogen rich carbon species and reduced oxidation temperature of coke substantially. Furthermore, agglomeration of Pt particles was partially impeded by coexisting Gd metal on the regenerated ZSM-5 catalyst. Synergetic effects of Pt and Gd promoters stabilized the PG yield and product distribution over the Pt–Gd/ZSM-5 catalyst during the cracking and regeneration cycles.

Ion-exchange selectivity of diclofenac, ibuprofen, ketoprofen, and naproxen in ureolyzed human urine

This research advances the knowledge of ion-exchange of four non-steroidal anti-inflammatory drugs (NSAIDs) – diclofenac (DCF), ibuprofen (IBP), ketoprofen (KTP), and naproxen (NPX) – and one analgesic drug–paracetamol (PCM) – by strong-base anion exchange resin (AER) in synthetic ureolyzed urine. Freundlich, Langmuir, Dubinin–Astakhov, and Dubinin–Radushkevich isotherm models were fit to experimental equilibrium data using nonlinear least squares method. Favorable ion-exchange was observed for DCF, KTP, and NPX, whereas unfavorable ion-exchange was observed for IBP and PCM. The ion-exchange selectivity of the AER was enhanced by van der Waals interactions between the pharmaceutical and AER as well as the hydrophobicity of the pharmaceutical. For instance, the high selectivity of the AER for DCF was due to the combination of Coulombic interactions between quaternary ammonium functional group of resin and carboxylate functional group of DCF, van der Waals interactions between polystyrene resin matrix and benzene rings of DCF, and possibly hydrogen bonding between dimethylethanol amine functional group side chain and carboxylate and amine functional groups of DCF. Based on analysis of covariance, the presence of multiple pharmaceuticals did not have a significant effect on ion-exchange removal when the NSAIDs were combined in solution. The AER reached saturation of the pharmaceuticals in a continuous-flow column at varying bed volumes following a decreasing order of DCF > NPX ≈ KTP > IBP. Complete regeneration of the column was achieved using a 5% (m/m) NaCl, equal-volume water–methanol solution. Results from multiple treatment and regeneration cycles provide insight into the practical application of pharmaceutical ion-exchange in ureolyzed urine using AER.

Establishment of an efficient and rapid method of multiple shoot regeneration and a comparative phenolics profile in in vitro and greenhouse-grown plants of psophocarpus tetragonolobus (L.) DC

An in vitro method of multiple shoot induction and plant regeneration in Psophocarpus tetragonolobus (L.) DC was developed. Cotyledons, hypocotyls, epicotyls, internodal and young seedling leaves were used as explants. MS media supplemented with various concentrations of either thidiazuron (TDZ) or N6-benzylaminopurine (BAP) along with NAA or IAA combinations were used to determine their influence on multiple shoot induction. MS media supplemented with TDZ induced direct shoot regeneration when epicotyls and internodal segments were used as explants. TDZ at 3 mg L−1 induced highest rate (89.2 ± 3.28%) of regeneration with (13.4 ± 2.04) shoots per explant. MS media supplemented with BAP in combination with NAA or IAA induced callus mediated regeneration when cotyledons and hypocotyls were used as explants. BAP (2.5 mg L−1) and IAA (0.2 mg L−1) induced highest rate (100 ± 2.66%) of regeneration with (23.2 ± 2.66) shoots per explant. Mature plants produced from regenerated shoots were transferred successfully to the greenhouse. In a comparative study, the phenolics contents of various parts of greenhouse-grown plants with that of in vitro-raised plants showed significant variations.

CO2 capture with complex absorbent of ionic liquid, surfactant and water

A new kind of high efficiency and low cost CO2 complex absorbent was studied. Through innovative research, imidazolium-based ionic liquid was mixed with an aqueous solution of a non-ionic surfactant. The absorption ability of each complex absorbent with different concentrations was tested under a condition of 20°C, from 0.1 to 0.6MPa. The absorption capacity of CO2 in absorbents increases with increasing pressure and concentrations of ionic liquids. Different aqueous ionic liquid–surfactant solutions had different CO2 absorption, and the sequence was as follows: X-100>TWEEN 80>PEG 400. [emim] [OTf] was more likely to absorb CO2 than the other four ionic liquids. All of the complex absorbents had good absorption properties. The best combination was made up of 5% TWEEN 80, 10% [emim] [OTf] and water, which could capture 0.798molL−1 CO2 at 0.6MPa while pure water could only capture 0.439molL−1 under the same conditions. Through computer numerical simulations, the experimental data could be well fitted with Henry’s law and Langmuir isothermal adsorption equation. After multiple absorption and regeneration, the absorption capacity of the complex absorbent was reduced by less than 5%. It could be expected to be a new type of CO2 capture absorbent.

Research on the design and control strategy for a flow-coupling-based hydraulic hybrid excavator

This paper presents a hybridization structure for the flow coupling of a hydraulic hybrid excavator. Multiple energy regeneration systems are used as the energy source for the hydraulic hybrid excavator. The flow-coupling structure is designed on the basis of practical working conditions and then integrated into a 23 ton excavator as the experimental platform to facilitate power system design and control studies. The initial constant-hybrid-ratio control is first examined using a simulation model to obtain the control performances of the main power source and the assistant power source, and the problems are then analysed to derive a two-step optimization. Prototype experiments demonstrate the effectiveness and feasibility of the flow-coupling-based hybridization structure of the hydraulic hybrid excavator. Test results indicate that flow coupling with an optimal control strategy results in an improved control performance and energy efficiency and can eventually increase the overall energy- saving effect to 10.1%.