A new benchmark reference solution for double-diffusive convection in a heterogeneous porous medium

ABSTRACT

A new benchmark with a high accurate solution is proposed for the verification of numerical codes dealing with double-diffusive convection in a heterogeneous porous medium. The new benchmark is inspired by the popular problem of square porous cavity by assuming a stratified porous medium. A high accurate steady state solution is developed using the Fourier–Galerkin method. To this aim, the unknowns are expanded in double infinite Fourier series. The accuracy of the developed solution is assessed in terms of the truncation orders of the Fourier series. Comparison against finite element solutions highlights the worthiness of the proposed benchmark for numerical code validation.     

Classification,characterization, and the production processes of biopolymers used in the textiles industry

This article is focused on biopolymers as intelligent environmentally friendly polymers, the production processes, and coatings of biotextiles used in different industries for next generation environmental applications. Furthermore, classification and composition of biodegradable polymers, the theoretical techniques, and factorial experimental designs for the optimization of processes with intelligent biotextiles used as an alternative to commercial chemical-based textiles at reasonable cost with a zero to low environmental footprint are discussed. This article will also provide how these novel modeling methodologies will assist polymer designers in making the best decision. The present work also discusses how the fully biodegradable polymers support the textiles industry by decreasing the processing energy, material, and manufacturing costs. Finally, current development as well as potential future applications and trends of biodegradable polymers in modern biodegradable textiles industry will be presented.     

Magnetic immobilization of recombinant E. coli producing extracellular asparaginase: An effective way to intensify downstream process

Purification is one of the most important steps in biotechnological downstream process. This procedure is associated with some difficulties including several separation steps. Common cell separation procedures are usually time and energy consuming that also compromises cell growth, viability and reusability. Magnetic immobilization was introduced as a novel separation technique to provide a quick, easy and convenient alternative vs. traditional cell harvesting methods. In this study, recombinant E. coli producing extracellular asparaginase was decorated by synthesized L-lysine coated iron oxide nanoparticles and cell growth, immobilization efficiency and asparaginase productivity was evaluated.     

Modelling of the blend ratio effect on the mechanical properties of the biofibres

This work investigates the effect of the blend ratios of three different environmental-friendly biopolymers on fibres’ properties made by water bath extrusion machine and multi-stage drawing frame. Tensile test, shrinkage test, differential scanning calorimetry and scanning electron microscopy are used to study the mechanical and thermal properties of composed fibres. In the modelling stage, stepwise regressions were used as faster and less prone technique to over fit the results by watching the order in which blend ratios are increased or decreased, that help to meet the requirements of specific applications. The statistical-based models control the biodegradable fibre properties beyond the selected range of the blend ratios more than that can be obtained from single polymer equivalents. The forecasting designed program simulates the relationship between the blend ratios and the biofibre’ properties to save both time and cost of the production process, this novel method steps could be applied on different polymers.     

Development of Emu oil-loaded PCL/collagen bioactive nanofibers for proliferation and stemness preservation of human adipose-derived stem cells: possible application in regenerative medicine

Adipose tissue-derived stem cells (ASCs) are promising candidate in stem cell therapies, and maintaining their stemness potential is vital to achieve effective treatment. Natural-based scaffolds have been recently attracted increasing attention in nanomedicine and drug delivery. In the present study, a polymeric nanofibrous scaffold was developed based on the polycaprolactone/Collagen (PCL/Coll) containing Emu oil as a bioactive material to induce the proliferation of ASCs, while simultaneously preserving the stemness property of those cells. Fabrication of the electrospun Emu oil-loaded PCL/Coll nanofibers was confirmed by using FE-SEM, FTIR, and tensile test. ASCs were seeded on two types of nanofibers (PCL/Coll and Emu oil-loaded PCL/Coll) and their proliferation, cell cycle progression, and stemness gene expressions were evaluated using MTT, propidium iodide staining, and qPCR during 14?days, respectively. The results indicated that ASCs displayed improved adhesion capacity with the higher rates of bioactivity and proliferation on the Emu oil-loaded nanofibers than the other groups. The proliferation capacity of ASCs on Emu oil-loaded PCL/Coll nanofibers was further confirmed by the cell cycle progression analysis. It was also found that Emu oil-loaded nanofibers significantly up-regulated the expression of stemness markers including sox-2, nanog, oct4, klf4, and c-Myc. The results demonstrated that the nanofibers containing Emu oil can reinforce the cell adhesion and enhance ASCs proliferation while preserving their stemness; therefore, using scaffolds containing natural products may have a great potential to enhance the in vitro expansion capacity of ASCs in the field of stem cell therapy and regenerative medicine.     

SOURCE ROCK CHARACTERIZATION BASED ON BIOLOGICAL MARKER DISTRIBUTIONS OF CRUDE OILS IN THE SOUTHERN GULF OF SUEZ, EGYPT

The depositional environment and maturity of source rocks in the southern Gulf of Suez were evaluated using biomarker and isotope data from crude oils derived from a variety of source rock types of different geological ages. Two oils families were identified and are referred to as types A and B. Type A oils are characterized by a predominance of oleanane and relatively low gammacerane concentrations, suggesting that they were derived from a terrigenous source rock with a significant input of angiosperm material inferred to occur within the marginally-mature syn-rift Lower Miocene Rudeis Shale. By contrast, type B oils are distinguished by a predominance of gammacerane and relatively low oleanane concentrations, suggesting that they were generated from mature marine carbonate source rocks inferred to occur within the Upper Cretaceous Brown Limestone and Middle Eocene Thebes Formation. Maturity parameters including the sterane isomerisation ratios C ₂₉αββ/(αββ+ααα), C₂₉ααα20S/(S+R) and TAS/(TAS+MAS), together with aromatic sulphur compound ratios (4-MDBT / I-MDBT; 4,6- / 1,4-DMDBT; 2,4–/ 1,4-DMDBT; and DBT / phenanthrenes), support the higher thermal maturity of type B oils relative to type A oils.
The biomarker variablility reflects the occurrence of two distinct source rocks in the southern Gulf of Suez and suggests that two independent petroleum systems are present here. These appear to be confined to the pre-rift (pre-Miocene) and syn-rift megasequences respectively.     

A Reference Benchmark Solution for Free Convection in A Square Cavity Filled with A Heterogeneous Porous Medium

The Fourier-Galerkin (FG) method is used to produce a highly accurate solution for free convection in a square cavity filled with heterogeneous porous medium. To this end, the governing equations are reformulated in terms of the temperature and the stream function. These unknowns are then expanded in infinite Fourier series truncated at given orders. The accuracy of the FG solution is investigated for different truncation orders and compared to the results of an advanced finite-element numerical model using fine-mesh discretization. The obtained results represent a set of high-quality data that can be used for benchmarking numerical models.