Search

Breast cancer is one of the most common cancers in Iran and round the globe. Seroma formation is the most common primary complication after mastectomy (partial/radical). Nowadays, drainage is used as a routine method to reduce seroma formation after mastectomy, although there is no consensus about the appropriate time to perform drainage after this surgery. This study evaluated the effects of short-term and long-term drainage after mastectomy along with removal of axillary lymph nodes.This randomized clinical trial was performed on 88 women who underwent mastectomy with ALND in hospitals in Yazd (were randomly divided into two groups). Suction drains were inserted for all patients at completion of surgery. The data collection tool was a researcher-made form based on variables. In the first group, the drain was removed 24 hours after surgery and the patients were discharged, but the second group was discharged with the drain in place after 24 hours and the drain was removed 5 days after surgery. Data were analyzed with SPSS18 using T-Test, Chi square, and Mann-Whitney U test.The results showed that 28 (31.8%) participants had formed seroma, of whom 22 (50%) were in the 1-day drainage group and 6 (13.6%) were in the 5-day drainage group. There was a statistically significant correlation among seroma frequency, mean aspiration volume, mean number of aspirations, mean seroma volume in sonography one week after surgery, and mean seroma volume in sonography between the two groups three weeks after surgery (P0.05).Based on the results, it can be concluded that long-term drainage reduces the risk of seroma formation after mastectomy with removal of axillary lymph nodes compared to short-term drainage. Complementary study be performed by considering other underlying factors such as comorbidities to obtain the best drain removal time in breast cancer patients.

We consider a solar microgrid design and dispatch problem using an adaptive stochastic optimization framework. First, we propose a two-stage mixed-integer model for optimal placement and planning of distributed generation (DG) units and energy storage system units. We incorporate time series modeling into stochastic optimization approach to characterize the solar irradiance uncertainty. In the first stage, design decisions (e.g., location and sizing of DGs) are made and in the second stage, dispatch decisions (e.g., how much to generate, how much to store) are made such that electricity demand is met in a reliable and cost effective way. Chance constraints are employed to control the real load shedding within a predefined probability level. Then, we propose a combined sample average approximation (SAA) and linearization technique to solve this problem more efficiently. The advantage of this approach is that no additional binary variables are introduced while reformulating the chance constraints. Computational time, quality of solution, and load shedding percentage are compared with the traditional SAA. Moreover, we carry out a comprehensive out-of-sample simulation on a real-world case study in the state of Arizona assessing the effectiveness of our approach. Numerical experiments demonstrate that the chance constraints are effective tools for control of load shedding in distributed generation and the proposed approach outperforms traditional methods both in terms of true load shedding percentage and computational time.

Both intramolecular [4 + 2] and intermolecular [3 + 2] cycloaddition reactions for the synthesis of 1,3-dioxoepoxyisoindole and epoxypyrrolo[3,4-g]indazoles, respectively, experimentally explored by Alizadeh and co-workers, were studied theoretically at the M06-2X/6-311G(d,p) computational level in both gaseous and solution (acetonitrile, benzene and DMSO) phases. In the first stage, it was studied the intramolecular [4 + 2] cycloaddition reaction generating potentially two diastereomeric adducts and it was confirmed the formation of experimentally reported product, 1,3-dioxoepoxyisoindole DEI-1 by the local reactivity indices as well as potential energy surface analysis. In the second stage, the [3 + 2] cycloaddition reaction of DEI-1 with three nitrilimines including NI–H, NI-C and NI–N, which generates potentially four possible regio- and stereoisomeric adducts was studied. The local reactivity indices described satisfactorily the experimentally observed regioselectivities. The results of potential energy surface analysis indicated that among the four possible products, only two exo regioisomeric adducts (namely, epoxypyrrolo[3,4-g]indazoles, CA-x1 and CA-x2) can be formed. In fact, for the reaction of DEI-1 with NI–H, NI-C and NI–H, the ratio of CA-x1:CA-x2 was estimated to be 57:43, 86:14 and 39:61, respectively, which is in satisfactory agreement with the experimental outcomes. The structural variations during the reactions were also studied and the results indicated that the transition states are not completely synchronous.

In the current research, a three component reaction [reported experimentally by Li et al. (Org Lett 19:1192–1195, 2017)] between the C60 fullerene, indole and propargyl bromide is studied theoretically. According to the proposed mechanism in the experimental work, nucleophilic attack of indole anion (Ind−) to C60 affords fulleroindole monoanion (FI) as an intermediate, which experiences another nucleophilic attack on certain primary organohalides to generate the corresponding 1,4-(3-indole)(organo)[60]fullerenes. To investigate the reaction from the mechanistic point of view, certain competition paths were designed between the starting materials in each step and some theoretical quantities were obtained and elucidated. In consistence with the experimental findings, the local Fukui as well as Parr functions reactivity indices confirmed the observed regioselectivity in the first step of the reaction. These local reactivity indices implied also that in the nucleophilic attack of FI on the organohalides, one of the ortho positions is more nucleophilically activated than para position. A PES analysis on the proposed reaction paths revealed a good agreement with the experimental findings. The electron transfer studies and the computation of molecular electrostatic potential (MEP) map of the transition states suggested that in addition to the steric repulsions, the electronic repulsions in the ortho positions determines the para-selectivity preference over the ortho ones.

A theoretical study at the levels of CAM-B3LYP and MP2 was reported, with the aim of understanding the possibility of functionalization of the C20 fullerene with pyridine and pyrimidine via a cycloaddition reaction. For this purpose, several [2+2] and [4+2] cycloaddition reactions were considered between C20 and pyridine or pyrimidine, and their thermodynamic and kinetic parameters were calculated. The results indicated that those [4+2] cycloaddition reactions are favorable ones in which the fullerene plays the role of a dienophile. It was also found that a [4+2] reaction path in which it takes place via the formation of two new C–C bonds between two fragments, C20 and heterocycle, is more favorable than that occurring via the formation of two different bonds, C-C and C–N. The calculation of global electron density transfer (GEDT) and molecular electrostatic potential (MESP) map revealed that the transition states are relatively polar and the C20 fullerene acts as an electron acceptor. Determination of Frontier Effective-for-Reaction Molecular Orbitals (FERMOs) relevant to pyridine and pyrimidine satisfactorily described the reactivity of different active sites of pyridine and pyrimidine. Finally, the calculation of the reactions synchronicity showed that the reactions are relatively synchronous.

Wettability is an essential component of reservoir characterization and plays a crucial role in understanding the dominant mechanisms in enhancing recovery from oil reservoirs. Wettability affects oil recovery by changing (drainage and imbibition) capillary pressure and relative permeability curves. This paper aims to investigate the role of wettability in matrix-fracture fluid transfer and oil recovery in naturally fractured reservoirs. Two experimental micromodels and one geological outcrop model were selected for this study. Three relative permeability and capillary pressure curves were assigned to study the role of matrix wettability. Linear relative permeability curves were given to the fractures. A complex system modelling platform (CSMP++) has been used to simulate water and polymer flooding in different wettability conditions. Comparing the micromodel data, CSMP++ and Eclipse validated and verified CSMP++. Based on the results, the effect of wettability alteration during water flooding is stronger than in polymer flooding. In addition, higher matrix-to-fracture permeability ratio makes wettability alteration more effective. The results of this study revealed that although an increase in flow rate decreases oil recovery in water-wet medium, it is independent of flow rate in the oil-wet system. Visualized data indicated that displacement mechanisms are different in oil-wet, mixed-wet and water-wet media. Earlier fracture breakthrough, later matrix breakthrough and generation and swelling of displacing phase at locations with high horizontal permeability contrast are the most important features of enhanced oil recovery in naturally fractured oil-wet rocks.

The decision to save or extract a natural tooth which has been compromised is one of the dilemmas of dental practitioners, as well as the patients. Although there was a considerable effort to save the natural teeth in the past, with the introduction of osseointegrated implants, there is a tendency to extract the compromised teeth and replace them with implant-supported prosthesis. In this article, this important clinical decision is investigated, and a successful restoration of a traumatized anterior tooth is presented.

Asphaltene precipitation during natural depletion and enhanced oil recovery (EOR) methods is one of the problematic challenges, which can affect the production in oil reservoirs. Asphaltenes as the most surface-active agents in the crude oil can interfacially interact with water molecules. As asphaltenes absorb to oil/water interface, water potentially can be involved and affect asphaltenes surface activity. This paper set out to investigate the surface activity of asphaltenes at the oil/water interface. Extensive sets of IFT tests were conducted with synthetic oil extracted from three different real reservoir crude oil samples in the presence of the distilled water. Results showed that IFT changes are not the dominant function of asphaltenes bulk concentration. However, it was revealed that asphaltenes surface concentration, which is dependent on the thermodynamic stability of asphaltenes within the bulk, controls IFT changes. Further, it was shown that IFT changes versus pressure are non-linear, indicating a non-linear function of asphaltenes surface behavior against pressure. Diluting a crude oil sample with normal heptane (n-C7) at various dilution ratios, indicated that dilution with a precipitant causes asphaltenes to be less surface active. The results of this study indicated that aging reduces asphaltenes surface activity only when the crude oil is diluted which revealed that asphaltene precipitation is a time-dependent phenomenon. Finally, it identified that sudden pressure shocks have no significant effect on asphaltenes behavior in crude oil. The results of this study shed new light on the mechanism of the asphaltenes surface behavior at oil/water interface which could be of crucial importance in flow assurance engineering as well as water flooding process.

Background The management of noncavitated caries lesions before sealant therapy is a clinical challenge when the tooth needs sealant application. Sealing noncavitated carious lesions in pits and fissures may lead to failure of the fissure sealant (FS) due to incomplete sealing. Therefore the use of remineralizing agents such as nanoparticles has been suggested. This study investigated the ability of hydroxyapatite nanoparticles (nano-HA) to remineralize enamel, and their effect on sealant microleakage and shear bond strength (SBS). Methods A total of 192 third molars were demineralized and pretreated with two concentrations of nano-HA with and without sodium hexametaphosphate (SHMP), followed by phosphoric acid etching and resin FS application. The study groups were 1) etching + FS, 2) etching + nano-HA 0.15% + FS, 3) etching + nano-HA 0.03% + FS, 4) etching + mixture of nano-HA 0.15% and SHMP 0.05% + FS, 5) etching + mixture of nano-HA 0.03% + SHMP 0.01% + FS. The laboratory tests included microleakage in 50 teeth, scanning electron microscopy (SEM) evaluation in 10 samples, and SBS in 100 samples. Enamel remineralization changes were evaluated in 32 teeth with energy-dispersive X-ray spectroscopy (EDS) and field emission scanning electron microscope (FESEM). Results Nano-HA enhanced the SBS to remineralized enamel in a large percentage of nanoparticles. Mean SBS in group 2 was significantly greater than in groups 1, 3 and 4 (all P 0.05). SEM images showed that SHMP did not affect sealant penetration into the deeper parts of fissures. FESEM images showed that adding SHMP led to increased nanoparticle dispersal on the tooth surface and less cluster formation. Conclusions The ultraconservative approach (combining nano-HA 0.15% and SHMP) and FS may be considered a minimal intervention in dentistry to seal demineralized enamel pits and fissures.

During the last decade, the hydrate-based CO2 capture (HBCC) process has been approved as a promising alternative. The HBCC offers several attractive advantages such as the mild operating pressure and temperature, the ease of regeneration of CO2, and its low energy consumption. The HBCC is at its infancy stage where the numerical methods play a key role in its research and development. This is to support the experimental research in terms of the model-based experiment design and process analysis/optimisation. In this view, HBCC modelling and simulation have been focused by researchers worldwide. Most of the published models are restricted to the processes at the particle scale that are enormously beneficial for a fundamental understanding of the process science. Nevertheless, a challenging shortfall currently exists for reactor scale models given the process scale research, and development objectives require models at the relevant scale. Accordingly, the reactor level models that may be used in a comprehensive process are required. Ideally, a multi-scale model allows studying both science and technology. This paper presents an HBCC process model at the reactor level for batch and semi-batch operations. The scaled-up model is capable of simulating the CO2 dissolution, and growth phases. The model evaluates the hydrate layer boundary and estimates the total gas uptake in batch semi-batch reactors. A modified version of the model made it possible to account. The present study establishes a groundwork for the large-scale application of the HBCC.

Implant-retained auricular prostheses provide an excellent treatment option with better retention and stability than a conventionally retained prosthesis. This article presents a technique for auricular reconstruction for a patient with misplaced implants. The scanning process combined the use of an intraoral scanner and a facial scanner to enhance accuracy in space management for different parts of the auricular prosthesis and to reduce sculpting time.

Enhanced Oil Recovery (EOR) through various methodologies has been an active research for many years seeking efficient methods to increase the crude oil recovery efficiency from oil reservoirs. Among different gas injection scenarios, carbon dioxide (CO2), natural gas (mainly methane (CH4)) and nitrogen (N2) injection are considered as promising EOR agents. Asphaltene precipitation and deposition during EOR methods cause severe problems, which affect the recovery efficiency and increase the cost of the incremental oil production. This study is aimed to investigate the effects of CH4 and N2 injection compared with CO2 injection on asphaltene precipitation and deposition. The different mole percent of the mentioned gases were introduced into the high-pressure cell, then the amount of precipitated asphaltene was measured at the reservoir condition. The evolution of asphaltene deposition was monitored through a high-resolution microscope. Moreover, Image processing software was utilized to check the amount of deposited asphaltene and its size distribution under different conditions. The most apparent finding to emerge from this study is that both CO2 and natural gas increase the amount of precipitated asphaltene whereas the nitrogen as an inert gas has no considerable effect on the amount of precipitated asphaltene. According to the results, the increment of precipitated asphaltene by CO2 is much higher than natural gas. Further, the thermodynamic solid model used in this study reasonably predicted the trend of asphaltene precipitation process for the mentioned EOR scenarios.

Application of the suspended solid particles in the base fluids is one of the novel methods to increase the thermal performance of heat transfer fluids. However, the major problems with this technique are the short time colloidal stability, low thermal conductivity of additive as well as significant negative effects on rheological properties once loading nanoparticles. The present study explores, for the first time, the impacts of graphene quantum dot (GQD) on the colloidal stability and thermophysical properties of water-based GQD suspensions as a new generation of heat transfer fluid. To this end, amine-treated GQD (A-GQD) were synthesized with a novel method. Surface functionality groups on A-GQD were analyzed by XPS. Atomic-force microscopy (AFM), UV–vis spectrometry, zeta potential and average particle size techniques have been used in order to measure and evaluate the colloidal stability, size and thickness of A-GQD. After applying A-GQD as an additive, colloidal stability results indicate no sedimentation after a 30-day period. In addition, all the thermophysical properties e.g. thermal conductivity, density and viscosity were measured experimentally. The viscosity of the water-based A-GQD samples was tested at various shear rates, concentrations and temperatures. Further, it has shown that by loading A-GODs in the water, the increasing rate of the density and viscosity is not significant. Interestingly, the water-based A-GQD nanofluids at very low concentration significantly increase the thermal conductivity in comparison with that of pure water.

In recent years, the air pollutant species has adventured the health of humans and other organisms. One of the pollutants are polycyclic aromatic compounds which are usually produced from defective combustion of fossil fuels. The removing or inactivation of these pollutants from environment is one of the research aims of scientists. In present work, the possibility of inactivation of the one of the polycyclic aromatic hydrocarbons namely pyrene with C20 fullerene was investigated theoretically. For this purpose, several [2+2] and [4+2] cycloaddition reactions between C20 and pyrene were considered and their thermodynamic and kinetic parameters were calculated. The results indicated that (a) one of the [4+2] paths is more favorable relative to others, (b) the most probable [4+2] Diels-Alder reaction of C20 and pyrene occurs with the rate constant of 5.09 × 10−6 M−1 s−1 at 25 °C, and (c) the reaction have relative polar character so that C20 fullerene and pyrene act as electron acceptor and donor, respectively. The Frontier Effective-for-Reaction Molecular Orbital (FERMO) concept was successfully applied for the description of the reactivity of the different active sites of pyrene. Finally, the synchronicity of the reactions was calculated and its correlation with activation enthalpy was elucidated.

Gas hydrate technology is a promising approach for carbon capture. However, due to the multi-physics and multi-scale complexity of the process, this technology is not sufficiently understood for real-life scale applications. In particular, further fundamental studies of the hydrate formation mechanisms and rate are needed to achieve relevant insights into the process design and intensification. High-fidelity numerical models are crucial to capture and explain the dominant physicochemical mechanisms involved in the process. This paper presents a new variation of the shrinking core model (SCM) that can capture the practically observed features of the carbon dioxide (CO2) hydration process, including the nucleation phase behavior and induction time, which have not been exploited previously. Accordingly, the most significant contribution of the current work to the literature is the proposal and demonstration of an efficient and rapid predictive tool for the CO2 hydrate nucleation process. Moreover, a model-based estimation of the induction time, as a critical parameter in CO2 hydrate rate estimation and control, is presented. Additionally, the temperature history profile over the nucleation and growth phases is simulated and compared against experimental data from the literature. The proposed model offers an in-depth and rationale analysis tool compared to the primary forms of the SCM and other models in which the nucleation stage has been compromised for the sake of mathematical modeling and numerical solution simplicity. The proposed concept is generic enough to be used for CH4 hydration process too.

To evaluate the effect of the application sequence of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) paste (MI paste) on shear bond strength (SBS) of 2 etch-and-rinse resin cements to dentin.Sixty extracted human maxillary premolars were cut to expose the mid-coronal dentin surfaces. The teeth were randomly divided into 6 groups (n = 10), based on the resin cement used and CPP-ACP application. In groups 1-3, Excite DSC/Variolink II and in groups 2-4, One-Step Plus/Duolink was bonded to dentin. There were 3 groups for each cement as follows: with no treatment as a control; 3-minute application of CPP-ACP before acid etching (CPP-ACP/Etching); 3-minute application of CPP-ACP after acid etching (Etching/CPP-ACP). After storage in distilled water at 37°C for 24 hours, SBS test was performed. Data were analyzed with 2-way ANOVA and post-hoc Tukey test (α = 0.05).CPP-ACP application on the dentin before and after acid etching significantly decreased the SBS of OS/Duolink (13.60 and 14.71 MPa, respectively vs. control; 21.21 MPa, p0.001); however, it did not influence the SBS of Excite DSC/Variolink II (25.14 MPa) before acid etching (27.37 MPa) or after acid etching (26.41 MPa, p0.388). The application sequence of CPP-ACP did not influence the SBS of etch-and-rinse resin cements evaluated.CPP-ACP applications may lower the SBS in some etch-and-rinse resin cements, and timing of applications makes no difference.

The hydrate-based carbon dioxide (CO2) capture (HBCC) process has been widely studied for CO2 separation and sequestration. This paper aims to conduct a model-based investigation of the kinetics of the HBCC process. A variation of the shrinking core model (SCM) was developed for the analysis of this heterogeneous system under varying boundary conditions. The results revealed that while CO2 diffusion through the hydrate layer is the dominant controlling mechanism, for a realistic scenario in which a time-dependent bulk gas concentration exists, the model results would better match the experimental data if the effects of the reaction rate were incorporated into the diffusion-based model. Sensitivity analysis showed that increasing the diffusivity through the hydrate layer significantly decreases the full conversion time of the water. Moreover, the effect of temperature change was investigated, and it was found that lower temperatures slow the hydrate growth rate. The model was demonstrated to be a computationally effective and time-efficient predictive tool that does not require high-speed computers for large-scale (reactor) applications.

University of Arizona Renewable Energy Network; National Science Foundation (NSF) [60050502]; NSF [CMMI-1555983]; U.S. Department of Energy Office of Electricity Delivery and Energy Reliability

This report describes a method to restore an implant with irreversibly damaged internal threads. The remaining fractured post from the previous restoration was removed using a combination of an impression coping and an end-cutting bur. An elastomeric impression of the internal surface of the damaged implant, as well as the position of the adjacent implant, was made for fabrication of a new cast post and core and an implant supported 2-unit ceramometal splinted prosthesis.

Asafetida is well known for its medicinal and therapeutic values in Iranian folk medicine. This study was conducted to investigate the antinociceptive and anti-inflammatory effects of asafetida. In hot plate test, asafetida exhibited a significant antinociceptive effect at all administered doses and the most effective dose was 10 mg/kg. The highest maximum potent effect was observed 15 minutes after asafetida administration. The antinociceptive effect of asafetida was not reversed by administration of any antagonist used in this study but asafetida showed a remarkable antioxidant and also inhibitory action against lipoxygenase activity. Paw weight was significantly reduced only in treated animals with 2.5 mg/kg asafetida. Results clearly indicate that the asafetida could be a potential source of anti-inflammatory and analgesic agent. These effects may be due to its effective constituents such as monoterpenes, flavonoids and phenolic components that have antioxidant properties and inhibit lipoxygenase activity.

In traditional Iranian medicine, asafoetida, an oleo-gum-resin obtained from the roots of Ferula assa-foetida, has been prescribed as a diuretic. This study was undertaken to investigate the diuretic effect of asafoetida in normal rats. Asafoetida was administered orally at the doses of 25 and 50 mg/kg and furosemide (10 mg/kg, intraperitoneal) was used as positive control. The diuretic effect was evaluated by measuring urine volume and sodium, potassium, urea, and creatinine content in urine and serum. Urine volume, excretion of sodium, and potassium were significantly increased by asafoetida as compared to the control group. A significant increase in creatinine clearance was observed in the groups treated with asafoetida at the doses of 25 and 50 mg/kg (P < 0.05). We conclude that asafoetida induced a diuretic effect comparable to that produced by the reference diuretic furosemide. This study provides a quantitative basis for explaining the folkloric use of asafoetida as a diuretic agent.

Statistical thermodynamic characterization was attempted for equilibrium hydrogen (H) absorption data in quasi-crystalline Ti0.45Zr0.38Ni0.17-Hx and amorphous Ti0.49Zr0.29Ni0.22-Si0.09Hx alloys. H atom distribution patterns in these non-crystalline multi-component alloys appeared to vary depending on the range of composition x. The border compositions x distinguishing between H atoms distribution patterns appeared to be closely related to the atom fraction of metal constituents, Ti, Zr and Ni, in the metal sub-lattice. In the Ti0.49Zr0.29Ni0.22-Si0.09Hx alloy, Si atom in interstitial site appeared to act as preferential trapping site for H atoms (3 H atoms per each Si atom). This statistical model was somewhat similar to a statistical model proposed earlier for Th-CzHx in which interstitial C atom promoted H absorption by turning the state of surrounding interstitial sites being favorable for occupation with H atoms (3 sites per each C atom).

The condensation process is of great importance in many heat transfer devices in which a large amount of energy must be transferred. Furthermore, condensation is a crucial part of energy conversion and affects the energy efficiency of thermal desalination plants and solar stills. During the condensation process in solar stills, an essential part of the energy is transferred through the condensation surface to produce fresh water. Therefore, the condensation surface plays a significant role in the working efficiency of solar stills. The wettability of the condensation surface influences the condensation mechanism, which, in turn, affects the efficiency of solar stills. This study aims to improve the efficiency of solar stills through wettability alteration of the condensation surface by utilizing nanoparticles. To this end, the condensation surfaces of various materials were selected and coated with titanium dioxide and silicon nanoparticles (which have different wetting properties) to increase and/or decrease the surface wettability. Outdoor and indoor experiments were conducted to evaluate the productivity of solar stills with regard to utilizing clean and nano-coated condensation surfaces. Furthermore, scanning electron microscopy and atomic force microscopy analyses were utilized to examine the deposition of nanoparticles on the condensation surfaces. The experimental results indicated that nano-coated condensation surfaces significantly improved the efficiency of solar stills. For instance, silicone coating caused an increase in the productivity of solar still by 20% for the glass condensation cover.

Asphaltene deposition during enhanced oil recovery (EOR) processes is one of the most problematic challenges in the petroleum industry, potentially resulting in flow blockage. Our understanding of the deposition mechanism with emphasis on the rate of the asphaltene deposition is still in its infancy and must be developed through a range of experiments and modelling studies. This study aims to investigate the rate of asphaltene deposition through a visual study under different gas injection scenarios. To visualise the asphaltene deposition, a high-pressure setup was designed and constructed, which enables us to record high-quality images of the deposition process over time. Present research compares the effects of nitrogen (N2), carbon dioxide (CO2) and methane (CH4) on the rate of asphaltene deposition at different pressures. The experimental results in the absence of gas injection revealed that the rate of asphaltene deposition increases at higher pressures. The results showed that the rate of asphaltene deposition in the case of CO2 injection is 1.2 times faster than CH4 injection at 100 bar pressure. However, N2 injection has less effect on the deposition rate. Finally, it has been concluded that the injection of CO2 leads to more asphaltene deposition in comparison with CH4 and N2. Moreover, the experimental results confirmed that gas injection affects the mechanism of asphaltene flocculation and leads to the formation of bigger flocculated asphaltene particles. The findings of this study can help for a better understanding of the mechanism of the asphaltene deposition during different gas-EOR processes.

PURPOSE To evaluate the influence of alloy/zirconia primer and 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing resin layer treatments on the shear bond strength (SBS) of composite resin to zirconia after aging. MATERIALS AND METHODS Sixty zirconia (Y-TZP) blocks were air-abraded (35-µm Al2 O3 ) and divided into 6 experimental groups (n = 10) in terms of primer/resin layer as follows: (1) control, without any primer or resin; (2) AP, Alloy Primer; (3) ZPP, Z-Prime Plus; (4) PL/ZPP, Z-Prime Plus with light polymerization; (5) AP+SEB, Alloy Primer along with light-cured bonding resin of a self-etch adhesive system (SE Bond); and (6) ZPP+SEB, Z-Prime Plus with SE Bond. After composite resin placement and light polymerization, the specimens were stored in distilled water (37°C for 4 months) and thermal-cycled for 6000 cycles. The SBS was tested with a universal testing machine. Statistical analysis of the SBS data was performed with one-way ANOVA, followed by HSD Tukey test (α = 0.05). RESULTS There were significant differences between the groups (p 0.05). CONCLUSIONS The bond strength between zirconia ceramic and composite resin was affected by different primers/resin layer. Applying an MDP-containing resin layer along with both primers resulted in significant enhancement of SBS. This improvement for Z-Prime Plus was significantly higher than that of Alloy Primer.

The main problem during field scale implantation of low salinity water injection (LSWI) is the decline in injectivity versus time. Moreover, the actual mechanisms that result in incremental oil recovery are not completely known. In previous studies, the geomechanical effects have not been considered, and pore volume changed while bulk volume is still constant which in turn can bring uncertainty to the simulation results. In this paper, both geochemical and geomechanical models have been coupled with the flow model. For coupling geomechanical model, three equations have been solved simultaneously in each time step. Then, the geochemical model has been coupled by adding the necessary aqueous and mineral reactions and ion concentration of both formation and injection waters. Increasing the Ca2+ concentration in the injected brine cause a reduction in the ultimate oil recovery. Also, increasing SO42− concentration in the injected brine up to about 70 ppm, resulted in increased oil recovery, while increasing the concentration caused a reduction in oil recovery. Injection above formation parting pressure (FPP) is beneficial but, there is a high uncertainty during injection above the FPP that can affect ultimate oil recovery and net present value. The results of this study show that geomechanical and rock parameters have intensive effects on the simulation results and rough estimating them in the simulation process can result in major errors and uncertainties. Further, it is very important to precisely include the dominant mechanisms of low salinity or smart water process during simulation studies.

CO2 transport from capture sources to storage sites is one of the leading parts of the carbon capture, and storage (CCS) infrastructure that needs to be optimized in order to reduce the capital, operating and maintenance (O&M) costs. This paper conducts a systematic overview of CO2 transport and identifies the knowledge gaps with a view for application to optimal CCS Hub design. The findings show that much research has been focused on the engineering and economic consequences in pure CO2 streams while in most real field studies the captured CO2 is accompanied with trace impurities that can affect the "intelligent" cost model's confidence to estimate CO2 pipeline costs. The impacts of different topographical conditions in current models on the economic pressure drop and inlet pressure is another challenge that has received little attention in the literature. Most cost-effective pipeline systems described in the literature, are based on the simple point-to-point design while the capture of CO2 from multiple sources and transport to multiple distributed CCS injection wells is an issue for the industrial-scale rollout of CCS. The lack of sufficient studies on the flow variations within CO2 networks is the last discussion in this research review. Further, there have been several cost models reported in the literature, and most of them are based on the costs of the natural gas pipeline infrastructure. However, the higher operating pressure of CO2 and the various impurities in CO2 streams from capture plant may require construction material specifications that will affect cost models. A systematic understanding of how CO2 pipelines contribute to CCS chain economics is still lacking. While many optimization challenges have been solved for natural gas pipeline networks, there are different thermodynamic behaviors for CO2 that require further optimization. The potential minor impurities that could occur in CO2 pipelines such as water (H2O), nitrogen (N2), oxygen (O2), hydrogen sulfide (H2S) and methane (CH4) can add complexity compared to the transport of natural gas.

Gas hydrates technology has been considered as an alternative method for carbon dioxide (CO2) separation. A wide range of studies have been reported in the past decade on the improvement of the separation efficiency by using chemical additives. While most of these studies have shown improved kinetics, thermodynamics and/or separation efficiency at the laboratory scale, there has been no quantitative analysis of the energy consumption for viable industrial applications. Comparison of the effectiveness of the chemical additives from separate studies or groups also is impossible. The present work is focused on the modelling of the hydrate-based CO2 separation process and provides a quantitative approach that is new in its analysis of the effectiveness of chemical additives in relation to the energy required and the kinetic parameters involved in the process.

Miscible carbon dioxide (CO2) flooding has become the most commonly and favorable approach in Enhanced Oil Recovery (EOR) because of its high oil reservoir sweep efficiency and contribution to the reduction of greenhouse gas emissions. Despite this, it can significantly favor the asphaltene deposition, which leads to the wettability reversal and formation damage. A novel experimental setup was utilized to study asphaltene deposition on the model rock at reservoir condition. The evolution of asphaltene deposition was monitored by a microscope; then analyzed by image processing software to check the amount of deposited asphaltene and its size distribution at different conditions. The amount of asphaltene deposition during natural pressure depletion and CO2 injection was measured experimentally and modeled using the thermodynamic solid model. The results indicated that during the pressure depletion process, asphaltene particles tend to dissolve in the solution. It is shown that the amount of asphaltene deposition increases as more CO2 is injected. Further, the thermodynamic solid model used for this case study included many empirical parameters required to match the experimental data comprehensively. A range of sensitivity analysis is carried out to investigate the effects of dominant parameters in this study. The proposed model used in this study reasonably predicted the trend of the asphaltene precipitation process for both pressure depletion and CO2 injection processes as oil recovery processes.

Cell formation problems attempt to assign machines and products to manufacturing cells so as to minimize inter-cell moves, in which some other aspects of the manufacturing system, such as time of order delivery, have been mostly neglected. To fill the gap, this paper addresses the cell formation problem and job scheduling simultaneously. To this end, a mixed integer nonlinear program is proposed to address issues related to both cell formation and job scheduling in a job shop layout. The proposed model minimizes the costs of operations and transportation in a single-period setting, since the problem considered is a strategic problem. Moreover, a hybrid simulated-annealing/genetic (SA/GA) algorithm is developed to cope with the complexity of the proposed model. Finally, numerical experiments are reported that validate the performance of the hybrid algorithm developed.

Hydrate-based CO2 capture (HBCC) has received increasing attention, due to such advantages as the mild operating pressure and temperature, the ease of regeneration and its unique separation mechanism. This review paper is focused on the chemical additives and the mechanical methods that have been investigated to improve the CO2 separation efficiency and energy consumption through HBCC technology. Detailed comparisons of the effects of various chemical additives and mechanical methods on gas consumption, operating conditions, hydrate induction time and CO2 recovery are critically reviewed. The limitations and challenges of HBCC, in comparison with the conventional methods for CO2 capture also are discussed.