Optimal rate allocation for production and injection wells in an oil and gas field for enhanced profitability

An oil and gas field requires careful operational planning and management via production optimization for increased recovery and long-term project profitability. This article addresses the challenge of production optimization in a field undergoing secondary recovery by water flooding. The field operates with limited processing capacity at the surface separators, pipeline pressure constraints, and water injection constraints; an economic indicator (net present value, NPV) is used as the objective function. The formulated optimization framework adequately integrates slow-paced subsurface dynamics using reservoir simulation, and fast-paced surface dynamics using sophisticated multiphase flow simulation in the upstream facilities. Optimization of this holistic long-term model is made possible by developing accurate second-order polynomial proxy models at each time step. The resulting formulation is solved as a nonlinear program using commercially available solvers. A comparative analysis is performed using MATLAB's fmincon solver and the IPOPT solver for their robustness, speed, and convergence stability in solving the proposed problem. By implementing two synthetic case studies, our mathematical programming approach determines the optimal production and injection rates of all wells and further demonstrates considerable improvement to the NPV obtained by simultaneously applying the tools of streamline, reservoir, and surface facility simulation for well rate allocation via systematic NLP optimization.     

Effect of Drying Methods on Dyeing Capacity of Dyestuff Plant Materials

This article presents a study of the effect of drying methods on dyeing capacity of widespread European flora dyestuff plant materials. The natural colorants, derived from the selected plant materials, were applied on chemical pulp in order to examine their dyeability. In this work, three different drying methods were examined—the natural, the air-, and the freeze-drying method—in various conditions. The plant materials that were dried naturally show weak dyeing results in comparison with the air- and freeze-dried materials. Freeze drying significantly improved the dyeing capacity of dyestuff plant materials with high initial moisture content. On the other hand, air drying at low temperature and high relative humidity improved the dyeing capacity of plant materials with low initial moisture content.     

Improving through-thickness conductivity of carbon fiber reinforced polymer using carbon nanotube/polyethylenimine at the interlaminar region

The through-thickness conductivity of carbon fiber reinforced polymer (CFRP) composite was increased by incorporating multiwalled carbon nanotubes in the interlaminar region. Carbon nanotubes (CNTs) were dispersed in a polyethylenimine (PEI) binder, which was then coated onto the carbon fiber fabric. Standard vacuum-assisted resin infusion process was applied to fabricate the composite laminates. This modification technique aims to enhance the electrical conductivity in through-thickness direction for the purpose of nondestructive testing, damage detection, and electromagnetic interference shielding. CNT concentrations ranging from 0 to 0.75 wt% were used and compared to pristine CFRP samples (reference). The through-thickness conductivity of the CFRP exhibited an improvement of up to 781% by adopting this technique. However, the dispersion of CNT in PEI led to a viscosity increase and poor wetting properties which resulted in the formation of voids/defects, poor adhesion (as shown in scanning electron micrographs) and the deterioration of the mechanical properties as manifested by interlaminar shear strength and dynamic mechanical analysis measurements.     

Structure and thermoelectric properties of higher manganese silicides synthesized by pack cementation

Higher manganese silicides (HMS) are promising alternative materials for middle to high temperature thermoelectric applications as a low-cost, non-toxic and highly stable p-type leg. Many of the preparation methods that have been reported previously require long-time and energy consuming processes, as well as expensive equipment, and often do not result in a material of sufficient quality. In this study, the simple, cost-effective and eco-friendly technique of pack cementation is applied. HMS powders synthesized at different experimental conditions are studied and compared considering their structure, composition, short-term thermal stability in air and thermoelectric properties. X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning electron microscopy, thermogravimetry and thermoelectric measurements (in terms of Seebeck coefficient, electrical and thermal conductivity) were employed for the characterization of the material and evaluation of its performance. All samples were identified as HMS and only some negligible traces of MnSi were detected. They moderately oxidize when heated non-isothermally under air atmosphere up to 1473 K, while the presence of HMS remains dominant even at such high temperatures. Their thermoelectric properties were remarkable for an undoped material, with a maximum figure of merit (ZT) of 0.47 at 777 K. Pack cementation appeared to have a great potential as the synthesis route of high-efficiency HMS.     

Environmentally Friendly Determination of Quality Parameters of Biodiesel/Diesel Blends Using Fourier Transform Infrared Spectra

Multivariate calibration models based on data from mid‐infrared spectroscopy of biodiesel/diesel blends were obtained. The blends were prepared from diesel oil and esters of soybean oil, waste cooking oil, and hydrogenated vegetable oil in proportions ranging from 0 to 100 % biodiesel. The results showed that the multivariate regression models with interval partial least squares (iPLS), backward interval partial least squares (biPLS), and synergy interval partial least squares (siPLS) were able to determine the fractions of the infrared spectrum that contain the relevant information for estimating the values of physicochemical properties, flash point, specific gravity, and cetane number, which are used in quality control of the blends. In the best models, the values of determination coefficients were greater than 0.9500, proving their efficiency as an alternative to traditional analytical methods.     

Evaluation of polyesters from renewable resources as alternatives to the current fossil-based polymers. Phase transitions of poly(butylene 2,5-furan-dicarboxylate)

Poly(butylene 2,5-furan dicarboxylate) (PBF) is an alipharomatic polyester that can be prepared using monomers derived from renewable resources such as 2,5-furan dicarboxylic acid and 1,4-butanediol. In the present work the thermal behavior of PBF was studied. Multiple melting was observed during heating traces of samples isothermally crystallized from the melt using differential scanning calorimetry (DSC). The wide angle X-ray diffraction (WAXD) patterns did not reveal the presence of a second crystal population, or a crystal transition upon heating. DSC study showed that the phenomena are closely related to recrystallization. Temperature modulated DSC (TMDSC) tests indeed evidenced enhanced recrystallization. The equilibrium melting point was estimated to be 184.5 °C using the linear Hoffman–Weeks extrapolation. The heat of fusion of the pure crystalline polymer was found equal to 129 J/g or (27.35 kJ/mol), a little lower than that of PBT. The Lauritzen–Hoffman secondary nucleation theory was used and the surface energy values and the work of chain folding were found to be comparable to those of PBT, but quite lower than those of poly(ethylene terephthalate) (PET). The non-isothermal crystallization on cooling and the cold-crystallization of quenched samples were also studied. Condensed spherulites were observed on isothermal crystallization under large supercoolings by using polarized optical microscopy (POM), while the spherulites turned to ring-banded morphology at higher temperatures. In every case the nucleation density was high.     

Morpholine As a Scaffold in Medicinal Chemistry: An Update on Synthetic Strategies

Morpholine is a frequently used heterocycle in medicinal chemistry and a privileged structural component of bioactive molecules. This is mainly due to its contribution to a plethora of biological activities as well as to an improved pharmacokinetic profile of such bioactive molecules. The synthesis of morpholines is a subject of much study due to their biological and pharmacological importance, with the last such review being published in 2013. Here, an overview of the main approaches toward morpholine synthesis or functionalization is presented, emphasizing on novel work which has not been reviewed so far. This review is an update on synthetic strategies leading to easily accessible libraries of bioactives which are of interest for drug discovery projects.     

A Holistic Evolutionary and 3D Pharmacophore Modelling Study Provides Insights into the Metabolism,Function, and Substrate Selectivity of the Human Monocarboxylate Transporter 4 (hMCT4)

Monocarboxylate transporters (MCTs) are of great research interest for their role in cancer cell metabolism and their potential ability to transport pharmacologically relevant compounds across the membrane. Each member of the MCT family could potentially provide novel therapeutic approaches to various diseases. The major differences among MCTs are related to each of their specific metabolic roles, their relative substrate and inhibitor affinities, the regulation of their expression, their intracellular localization, and their tissue distribution. MCT4 is the main mediator for the efflux of L-lactate produced in the cell. Thus, MCT4 maintains the glycolytic phenotype of the cancer cell by supplying the molecular resources for tumor cell proliferation and promotes the acidification of the extracellular microenvironment from the co-transport of protons. A promising therapeutic strategy in anti-cancer drug design is the selective inhibition of MCT4 for the glycolytic suppression of solid tumors. A small number of studies indicate molecules for dual inhibition of MCT1 and MCT4; however, no selective inhibitor with high-affinity for MCT4 has been identified. In this study, we attempt to approach the structural characteristics of MCT4 through an in silico pipeline for molecular modelling and pharmacophore elucidation towards the identification of specific inhibitors as a novel anti-cancer strategy.