Increase In Enthalpy Research Articles

Production and characterization of glibenclamide incorporated PLA filaments for 3D printing by fused deposition modeling

In this work a soaking method for incorporating glibenclamide (GBC), a poorly soluble API, into prefabricated polylactic acid (PLA) filaments intended for 3D printing by fused deposition modeling (FDM) was developed and evaluated. The swelling effect of multiple solvents and solvent mixtures on PLA was assessed to identify an optimal soaking solution. Water and l-arginine (ARG) were selected to modify the soaking method to enhance drug incorporation with minimal filament degradation. The presence of ARG enhanced GBC's solubility in the selected soaking solution and it was associated with a significant increase in the filaments' drug loading. Thermal and infrared spectroscopy studies revealed the absence of a glass transition (Tg) in the soaked filaments and a significant reduction in the melting temperature combined with an increase in the melting enthalpy indicating increased PLA crystallinity. In vitro dissolution studies with filaments and printed tablets indicated that GBC had been well dispersed into the PLA matrix during printing leading to a decrease in drug release. Instead, filaments soaked in GBC-ARG solutions demonstrated increased drug release compared with GBC on its own. Overall, our results show a simple method to improve drug incorporation of a poorly soluble API into PLA filaments via passive diffusion.

Global Warming by Geothermal Heat from Fracking: Energy Industry's Enthalpy Footprints.

Hypothetical dry adiabatic lapse rate (DALR) air expansion processes in atmosphere climate models that predict global warming cannot be the causal explanation of the experimentally observed mean lapse rate (approx.−6.5 K/km) in the troposphere. The DALR hypothesis violates the 2nd law of thermodynamics. A corollary of the heat balance revision of climate model predictions is that increasing the atmospheric concentration of a weak molecular transducer, CO2, could only have a net cooling effect, if any, on the biosphere interface temperatures between the lithosphere and atmosphere. The greenhouse-gas hypothesis, moreover, does not withstand scientific scrutiny against the experimental data. The global map of temperature difference contours is heterogeneous with various hotspots localized within specific land areas. There are regional patches of significant increases in time-average temperature differences, (∆<T>) = 3 K+, in a ring around the arctic circle, with similar hotspots in Brazil, South Africa and Madagascar, a 2–3 K band across central Australia, SE Europe centred in Poland, southern China and the Philippines. These global-warming map hotspots coincide with the locations of the most intensive fracking operational regions of the shale gas industry. Regional global warming is caused by an increase in geothermal conductivity following hydraulic fracture operations. The mean lapse rate (d<T>/dz)z at the surface of the lithosphere will decrease slightly in the regions where these operations have enhanced heat transfer. Geothermal heat from induced seismic activity has caused an irreversible increase in enthalpy (H) input into the overall energy balance at these locations. Investigating global warming further, we report the energy industry’s enthalpy outputs from the heat generated by all fuel consumption. We also calculate a global electricity usage enthalpy output. The global warming index, <∆T-biosphere> since 1950, presently +0.875 K, first became non-zero in the early 1970’s around the same time as natural gas usage began and has increased linearly by 0.0175 K/year ever since. Le Chatelier’s principle, applied to the dissipation processes of the biosphere’s ΔH-contours and [CO2] concentrations, helps to explain the global warming statistics.

Behavior of high-burnup BWR UO2 fuel with additives under reactivity-initiated accident conditions

ABSTRACT Fuels with additives are expected to provide enhanced fuel performance in fission gas retention owing to their large grain size, which elongates fission gas migration path. To investigate behavior of the fuels during a reactivity-initiated accident (RIA), RIA-simulated experiments OS-1 and LS-4 were performed on ADOPT (chromia- and alumina-doped UO2) fuel of 64 GWd/t and chromia-doped UO2 fuel of 48 GWd/t, respectively. The OS-1 rod failed at a fuel enthalpy increase of 160 J/g due to pellet–cladding mechanical interaction failure, which was the lowest failure limit among the test results ever obtained at the NSRR on high-burnup fuels from 40 to 65 GWd/tU. Comparison of the hydride morphologies in the cladding metallic layer between the rods subjected to the past NSRR tests suggests the contribution of radially oriented hydrides during base irradiation to the low failure limit. The LS-4 rod survived for a peak fuel enthalpy increase of 549 J/g, which resulted in cladding deformation of ~2.4% in the residual hoop strain and FGR of 1.4–6.1%. Whereas the low fission gas release exhibits the effect of additives, the cladding deformation is within the range explained by the deformation mechanism essentially identical to those recognized for high-burnup undoped fuels.

Heat transfer characteristics of supercritical water in a horizontal tube considering local temperature fields: An experimental study

A comprehensive understanding of heat transfer to supercritical fluids is essential to improve the thermal efficiency of some advanced thermal systems. However, the mechanism remains unclear that how the heat transfer is affected by local temperature, especially the near-wall temperature. In this study, heat transfer experiments of supercritical water are conducted in a horizontal tube. Five local water temperatures from the near-wall region to the core in a cross-section are measured to clarify the heat transfer process with the operating pressure of 23.5–26.5 MPa, mass flux of 200–400 kg·m–2 s–1, and heat flux of 50–180 kW·m–2. The tube length and inner diameter are 6000 mm and 26 mm, respectively. The results show that the heat transfer is suppressed and the enthalpy increase is no longer linear before the pseudo-critical point. Heat transfer is dominated by the relative magnitude of buoyancy and inertia force, which are affected by heat flux and mass flux, respectively. Moreover, the heat transfer process is divided into four parts, and the heat transfer deterioration occurs at the end of part II and restores in part III. Finally, a new correlation which is suitable for supercritical heat transfer in horizontal tubes with large diameters is developed based on the present experimental data.

Decelerated crystal growth in a soda-lime-silica glass

Isolated Na2O⋅2CaO⋅3SiO2 (NC2S3) single crystals grew at temperatures above glass transition in a melt with a slight soda excess. The enrichment of Na in the continuous solid solution Na4+2zCa4–z[Si6O18] (with 0 ≤ z ≤ 1) upon crystallisation causes a depletion of soda of the growing interfacial diffusion zone. Therefore its viscosity will change. Experimental data and idealized model calculations of the viscosity show the same trend and indicate that the viscosity of the interfacial zone would be up to several orders of magnitude higher than the viscosity of the melt. This increased viscosity at the crystal growth front and the experimentally observed decrease of the crystallisation velocity with crystal size suggest a linear increase of the effective activation enthalpy of the diffusional transport through the diffusion zone with crystal size, which allows to quantitatively model crystal growth data of the NC2S3 glass investigated.

Soild-state decomposition mechanisms with conversion extent for ammonium percholorate catalyzed with nanothermite particles

Colloidal ferric oxide/aluminum nanothermite mixture was incorporated into ammonium percholorate (AP). Nanothermite particles experienced an increase in AP decomposition enthalpy by 120% using DSC. Decomposition kinetic study was performed using integral isoconversional models including Kissinger and KAS models. Nanothermite particles offered decrease in AP activation energy by 55 and 44% using KAS and Kissinger models, respectively. AP nanocomposite is running through three decomposition steps according to extent of conversion: first-order decomposition with Ea = 41.08 kJ.mol−1 (α = 0: 0.25), two-dimensional decomposition with Ea = 71.90 kJ.mol−1 (α = 0.25: 0.6), and one-dimensional diffusion reaction with Ea = 97.10 kJ.mol−1 (α = 0.6:0.9).

The Starch Physicochemical Properties between Superior and Inferior Grains of Japonica Rice under Panicle Nitrogen Fertilizer Determine the Difference in Eating Quality.

Nitrogen fertilizer is essential for rice growth and development, and topdressing nitrogen fertilizer at panicle stage has a huge impact on rice grain quality. However, the effect of panicle nitrogen fertilizer (PNF) on starch physicochemical properties and fine structure remain unclear. In this study, four PNF levels (0, 60, 120, 180 kg N ha−1) were grown with the same basal and tiller fertilizer (150 kg N ha−1). The starch physicochemical properties, fine structure, texture properties and eating quality of two japonica rice were determined. We found that the content of total protein, crude fat and amylose between superior and inferior grains were significantly different. Compared with inferior grains, superior grains had low relative crystallinity, good pasting characteristics and outstanding eating quality. With the increase of nitrogen application rates, the starch volume mean diameter was lower; the average chain length of amylopectin was longer; and the relative crystallinity of starch was higher. The changes above in starch structure resulted in an increase in starch solubility, swelling power and gelatinization enthalpy, and led to a decrease in retrogradation enthalpy, retrogradation percentage and pasting viscosity, consequently contributing to the increase in hardness and stickiness of rice and the deterioration of taste value. These results indicated that topdressing PNF lengthened the amylopectin chain, decreased starch granule size, enhanced crystallization stability and increased gelatinization enthalpy, which were the direct reasons for the deterioration of cooking and eating quality.

First principles DFT analysis on the diffusion kinetics of hydrogen isotopes through bcc iron (Fe): Role of temperature and surface coverage

The diffusion of interstitial H, D, and T in Fe metal at different temperature are evaluated using ab-initio density functional theory and transition state theory. The thermal expansion coefficient, Helmholtz free energy of activation, jump factor of diffusion was determined by use of activation energy and phonon calculations. The calculated diffusion coefficient was well described by a constant activation energy, (D = D0exp (-Ea)/kT)) with Ea = 0.016, 0.041, and 0.050 eV and D0 = 1.042 × 10−7, 0.736 × 10−7 and 0.572x10−7 m2.s−1for H, D, and T, respectively using harmonic transition state theory (hTST) with temperature correction. The calculated permeability and solubility also followed the Arrhenius relation.The earlier experimentally reported higher diffusivity of H atom at lower temperatures than that at higher temperature (200–600 K) was well explained by Wigner + hTST model with temperature correction and semi-classical transition state theory (SC-TST). The present computed results followed the similar trend of experimental findings. Further, the ideal fracture energy was evaluated using the Born-Haber thermodynamic cycle for varied coverage of H, D and T to account for decohesion-based embrittlement. The lighter H atom was seen to cause more decohesion-based embrittlement compared to D and T due to reduced cohesion. Additionally, the effect of temperature on ideal fracture energy was evaluated for H, D and T in Fe. The decohesion-based embrittlement was increased with increase in the temperature for H, D and T up to certain temperature (for H lower than 500 K, for D around 500 K and for T above 500 K) but with further increase in the temperature, the ideal fracture energy was reduced due to decrease in the adsorption energy and increase in the solution enthalpy of H isotopes. Further, the path and kinetics of dissociation and reassociation of H2 molecule were established on Fe (100) surface at 0.5 and 2.0 ML coverage. At lower concentration (0.5 ML), dissociation of H2 molecule on Fe (100) surface was favored, whereas at high concentration (2.0 ML), reassociation of H2 molecule was favored.

Applications of an Association Activity Coefficient Model, NRTL-PA, to Alcohol-Containing Mixtures

A new activity coefficient method for associating systems, NRTL Plus Association (NRTL-PA), is developed and evaluated for alcohol + hydrocarbon systems. The method combines Wertheim’s perturbation theory using the PC-SAFT form of the association strength with Flory’s theory and a residual contribution represented with NRTL. The model is capable of accurate representation of simultaneous VLE, LLE, and excess enthalpy with the same set of parameters. The association contribution is fixed using literature values during regression to provide focus on the capabilities of combining Wertheim statistical mechanics with a residual activity model. The model is shown to be superior to the traditional NRTL model and represents accurately the increase in excess enthalpy as temperature increases. The NRTL-PA model is publicly available as an Aspen Plus user model.

Conformational Dynamics of Glucagon-like Peptide-2 with Different Electric Field.

Molecular dynamics (MD) simulation was used to study the influence of electric field on Glucagon-like Peptide-2 (GLP-2). Different electric field strengths (0 V/nm ≤ E ≤ 1 V/nm) were mainly carried out on GLP-2. The structural changes in GLP-2 were analyzed by the Root Mean Square Deviation (RMSD), Root Mean Square Fluctuation (RMSF), Radius of Gyration (Rg), Solvent Accessible Surface Area (SASA), Secondary Structure and the number of hydrogen bonds. The stable α—helix structure of GLP-2 was unwound and transformed into an unstable Turn and Coil structure since the stability of the GLP-2 protein structure was reduced under the electric field. Our results show that the degree of unwinding of the GLP-2 structure was not linearly related to the electric field intensity. E = 0.5 V/nm was a special point where the degree of unwinding of the GLP-2 structure reached the maximum at this electric field strength. Under a weak electric field, E < 0.5 V/nm, the secondary structure of GLP-2 becomes loose, and the entropy of the chain increases. When E reaches a certain value (E > 0.5 V/nm), the electric force of the charged residues reaches equilibrium, along the z-direction. Considering the confinement of moving along another direction, the residue is less free. Thus, entropy decreases and enthalpy increases, which enhance the interaction of adjacent residues. It is of benefit to recover hydrogen bonds in the middle region of the protein. These investigations, about the effect of an electric field on the structure of GLP-2, can provide some theoretical basis for the biological function of GLP-2 in vivo.

Kinetic Study and Thermal Decomposition Mechanisms of Superthermite–Based Nitrocellulose Nanocomposite

ABSTRACT As ferric oxide is a well-known catalyst, aluminum can act as a high energy dense material. Ferric oxide/aluminum can experience nanothermite reaction with novel synergistic characteristics. On the other hand, nitrocellulose (NC) is the most energetic polymeric matrix. This study reports on the facile development of thermite-based NC nanocomposite. Ferric oxide nanoparticles (NPs) of 5 nm size and aluminum NPs of 80 nm size were dispersed in acetone. Colloidal ferric oxide/aluminum NPs were integrated into NC matrix via anti-solvent technique. Nanothermite particles offered an increase in NC decomposition enthalpy by 38.59% using differential scanning calorimetry (DSC). The apparent activation energy of NC was reduced by 14% and 14.5%, using Friedman and OZAW models, respectively. Activation energy at different conversion extent was evaluated, and decomposition mechanisms have been suggested to be heterogeneous solid phase reaction. The developed NC nanocomposite is considered bespoke material for first-fire ignition systems; where molten solid particle and high decomposition enthalpy are highly appreciated.

Investigation of the bulk and point defect properties in uranium–plutonium mixed oxides (U,Pu)O2 using DFT+U: Effect of a low americium content

We report an investigation of the effect of a low Am impurity content on bulk and point defect properties of mixed actinide oxide (U,Pu)O2. Using the generalized gradient approximation, (GGA + U) we study U0.75−zPu0.25AmzO2 with z = 3 and 6%. Several of its bulk properties have never been reported in the literature or are poorly known. The Hubbard term U is used to take into account the strong correlation effects related to the actinide 5f electrons. We find an electronic charge transfer between uranium and americium cations in the bulk crystal. Am(+IV) cations tend to easily reduce to Am(+III), and this reduction of Am(+IV) is compensated by the oxidation of U(+IV) to U(+V) in stoichiometric compounds. In turn, oxygen hypostoichiometry is accommodated by the reduction of U(+V) cations [which result from the presence of Am (+III) cations] before any reduction of the Pu cations. Furthermore, we show that Am induces a significant increase in the mixing enthalpy as well as a decrease in the lattice parameter of the (U,Pu)O2 solid solution, which is in agreement with early experimental studies. Finally, we show that americium facilitates the formation of oxygen vacancies in (U,Am)O2 compared to UO2, whereas it induces an increase in the formation energy of oxygen vacancies in (U,Pu,Am)O2 compared to (U,Pu)O2.

Photo- and magneto-responsive highly graphitized carbon based phase change composites for energy conversion and storage

Phase change material (PCM) as latent heat storage unit shows great potential in various scenes, including solar energy storage system and magnetically induced energy conversion and storage. But insufficient optical activity and electromagnetic response capability seriously hinder its wider applications. Herein, we reported an advanced high-performance photo- and magneto-driven composite phase change material (CPCM), where metal-organic framework (MOF) derived magnetic highly graphitized carbon (MGC) served as a fast-charging photo- and magneto-responsive supporting skeleton, and octadecanol (ODA) acted as a latent heat storage unit. In graphitic structure, there were numerous sp2 carbon atoms and π electrons. Under solar irradiation, heat is quickly discharged by lattice vibration resulting from π-π∗ transition and subsequent electron-phonon coupling in highly graphitized carbon. Moreover, in situ anchored magnetic cobalt nanoparticles contribute to another exothermic effect triggered by light and alternative magnetic field owing to its surface plasmon resonance (SPR) and eddy current effect, respectively. Additionally, cobalt nanoparticles can also serve as the heterogenous nucleation sites to promote the crystallinity of ODA molecules, thus profiting the increase of phase change enthalpy. Therefore, our developed cobalt-decorated highly graphitized carbon based photo- and magneto-responsive CPCM synergistically reached an enhanced photothermal efficiency of 88.1%, thermal energy storage capacity of 131.14 J/g, and excellent thermal cycling stability and reliability after undergoing multiple charging-discharging cycles, showing great potential in latent heat storage, solar and magnetic energy harvesting.

Analyzing Nematic to Isotropic (N-I) Phase Transition of nCB Liquid Crystals Using Logger Pro

This paper reports detailed analysis of Nematic to Isotropic (N-I) phase transition of n-Cyanobiphenyl (nCB) Liquid Crystals (LC) using Logger Pro. Three bulk samples of nCB liquid crystal family, 4-Pentyl-4'-cyanobiphenyl (5CB), 4-Hexyl-4'-cyanobiphenyl (6CB), and 4-Heptyl-4'-cyanobiphenyl (7CB) were processed through the Differential Scanning Calorimetry (DSC) instrument for heating and cooling scans. The DSC data is then analyzed using Logger Pro. Logger Pro is a data analysis tool used to collect and analyze data in educational institutes. Our interest is to use Logger Pro in the research area to analyze DSC data of these LCs to get detailed results of N-I phase transition. Logger pro has been proven to be a good data analysis tool to find results in detail for these LCs in this paper. It is found that as nCB gets heavier and its C-C tail gets larger, the N-I phase transition shifts towards higher temperature in heating and shows an increase in enthalpy, wings jump, molecular mobility and molecular disorder.

Biophysical Characterization of the Contribution of the Fab Region to the IgG-FcγRIIIa Interaction.

The cell-surface receptor FcγRIIIa is crucial to the efficacy of therapeutic antibodies as well as the immune response. The interaction of the Fc region of IgG molecules with FcγRIIIa has been characterized, but until recently, it was thought that the Fab regions were not involved in the interaction. To evaluate the influence of the Fab regions in a biophysical context, we carried out surface plasmon resonance analyses using recombinant FcγRIIIa ligands. A van't Hoff analysis revealed that compared to the interaction of the papain-digested Fc fragment with FcγRIIIa, the interaction of commercially available, full-length rituximab with FcγRIIIa had a more favorable binding enthalpy, a less favorable binding entropy, and a slower off rate. Similar results were obtained from analyses of IgG1 molecules and an IgG1-Fc fragment produced by Expi293 cells. For further validation, we also prepared a maltose-binding protein-linked IgG1-Fc fragment (MBP-Fc). The binding enthalpy of MBP-Fc was nearly equal to that of the IgG1-Fc fragment for the interaction with FcγRIIIa, indicating that such alternatives to the Fab domains as MBP do not positively contribute to the IgG-FcγRIIIa interactions. Our investigation strongly suggests that the Fab region directly interacts with FcγRIIIa, resulting in an increase in the binding enthalpy and a decrease in the dissociation rate, at the expense of favorable binding entropy.

Production and characterization of a coconut oil incorporated gelatin-based film and its potential biomedical application

The influence of coconut oil (CO) on a gelatin-based film was investigated when used as a potential wound dressing material. There is limited study on CO in protein-based wound dressing materials. Therefore, in this study a self-supporting, continuous and homogenous CO incorporated gelatin-based film was formulated and obtained by solution casting method. The influence of CO on physicochemical and thermal properties of gelatin-based film was also determined. Moreover, the effect CO in gelatin films on cell viability and cell migration was analysed with a preliminary cell culture study. Homogenous dispersion of 10% (w/w) CO was obtained in films when 3% (v/w) Tween 80, a surfactant, was incorporated to 20% (w/w) plasticized gelatin film forming solution. Effect of CO on gelatin-based film was observed via phase separation by scanning electron microscopy analysis. Water uptake of gelatin film with no CO, GE film; and 10% (w/w) CO incorporated GE film, GE-CO, were 320% and 210%, respectively, after 3 h in water. Fourier transform infrared spectroscopy analysis showed triglyceride component of CO and increased hydrogen bonding between NH groups of gelatin in GE-CO films. Differential scanning calorimetry results suggested a more ordered structure of GE-CO film due to an increase in melt-like transition temperature and melting enthalpy of GE-CO film. CO content also increased cell viability, assessed by XTT assay since cell viability was approximately 100% when L929 cell culture was incubated with GE-CO of 5–100 μg ml−1. Moreover, GE-CO samples within 5–25 μg ml−1 concentration range, increased proliferation of L929 cells since cell viability was significantly higher than the 100% viable cell culture control (P < 0.05) which is also an indication of efficient healing. However, GE decreased viability of L929 cells significantly at 100–10 μg ml−1 concentration range (P < 0.05) and were toxic at concentrations of 100, 75 and 50 μg ml−1 which decreased ∼50% of the viability of the cells. Scratch Assay to assess in vitro wound healing showed cell migration towards scratch after 24 h as an indication of wound healing only in GE-CO samples. This study showed that, CO could efficiently be added to gelatin-based films for preparation of a primary wound dressing biomaterial which is also demonstrated to have a promising wound healing effect for minor wounds.

Shock/expansion fan interaction with real gas effects for Earth and Mars atmospheric conditions

AbstractNumerical simulations are performed to investigate the real gas effects on shock/expansion fan interaction. Initial perfect gas simulations at low enthalpy capture the flow structures efficiently and outcomes are found to have excellent agreement with the analytical calculations. Furthermore, the simulations with the real gas solver for different enthalpies showed that the variation in enthalpy significantly changes the flow structures. It is observed that an increase in enthalpy leads to a decrease and increase in the postshock and postexpansion fan Mach numbers, respectively. Another important observation is the decrement in the peak pressure ratio with an increment in the enthalpy. These effects are noted to be more pronounced for Mars's environment due to the higher dependency of specific heat on temperature.

Rejuvenation by triaxial compression in a brittle La-based bulk metallic glass

Rejuvenation was achieved in brittle (La50Ce50)65Co25Al10 bulk metallic glasses (BMGs) by compressing a notched sample. The rejuvenated sample shows low hardness (reduced by 7%), high relaxation enthalpy (increased by 44%) compared with those of as-cast sample. Most importantly, our results show that, in terms of percentage increase in relaxation enthalpy per strain, the rejuvenation ability of La-based BMG is higher than that of Zr-based BMG under plastic deformation. Our findings demonstrated the powerful rejuvenation ability for triaxial compression once again.

Latent, Cross-Linkable Triazole Platform on a Carbon Fiber Surface for Enhancing Interfacial Cross-Linking within Carbon Fiber/Epoxy Composites

A long-running need in carbon fiber composite production is to ameliorate interfacial adhesion between the polymer and carbon fibers. Here, we present a convenient and feasible strategy for controlling the carbon fiber’s surface in a continuous process: syntheses of click-modified silanes via copper(I)-catalyzed azide–alkyne cycloaddition reaction and grafting them onto fiber surfaces which prepare a latent curable platform under mild processes without postmodification. As 1,2,3-triazole moieties from the click reaction were added to the epoxy/dicyandiamide system, they triggered additional reactions in the later conversion stage; approximately, a 20% increase in the total reaction enthalpy compared to the system with no additives was obtained. We expected the enhanced cross-linking between the surface and matrix to expand the interfacial area, leading to reinforcements on interfacial adhesion and stress-transfer abilities within composites. The merit of the approach is well-demonstrated by conductive atomic force microscopy, showing that the interphase can be extended up to 6-fold when the triazole platform acts as curatives and serve as bridges after the epoxy cure. Consequently, the composite’s interfacial shear strength and interlaminar shear strength were increased up to 78 and 72%, respectively. This work affords a reactive platform where a custom-tailored fiber/matrix interface can be designed by virtue of versatility in clickable reactants.

Reservoir Dynamics Monitoring in A Liquid Dominated Geothermal Field Based on Surveillance Data and Tracer Flow Test

Two common characteristics changes in the liquid-dominated reservoir because of exploitation are a decrease in temperature in the liquid reservoir zone (due to injection breakthrough) and the development of a steam zone (because of lower liquid water level). Both phenomena are observed by using the tracer flow test (TFT) technique. The comprehensive analysis using enthalpy from TFT data, combined with the data of chloride in brine, NCG in steam, and subsurface temperature (from PT logging), can be used to identify the dynamics of the reservoir processes. The application of the comprehensive analysis is selected for this study by taking those various monitoring of surveillance programs from a liquid-dominated geothermal system. In the selected geothermal field, which the operation began in 1994, an injection breakthrough occurred in the western part of the field. On the other side, the development of a steam reservoir was observed in the eastern part of the field. TFT monitoring is carried out every three months in each active production well as stated in the surveillance program. Other chemical monitoring and (PT) log data are also carried out periodically. Two wells from the studied field are selected, in which one well experience with injection breakthrough and the other one is in steam cap development. Comprehensive analysis results from TFT data, geochemical monitoring data (NCG and Cl), and subsurface temperature are used to understand the dynamics in geothermal reservoirs. Injection breakthrough in production well is indicated by changes in chloride content, decrease in enthalpy and NCG in the steam. Whereas the formation of steam cap will be characterized by an increase in enthalpy and NCG. With a thorough understanding of the changing conditions in the reservoir, recommendations for appropriate surveillance strategies can be formulated to maintain an optimal and sustainable generation process.