Timelike and Spacelike Matter Inheritance Vectors in Specific Forms of Energy-Momentum Tensor

This paper is devoted to the investigation of the consequences of timelike and spacelike matter inheritance vectors in specific forms of energy-momentum tensor, i.e., for string cosmology (string cloud and string fluid) and perfect fluid. Necessary and sufficient conditions are developed for a spacetime with string cosmology and perfect fluid to admit a timelike matter inheritance vector, parallel to $u^a$ and spacelike matter inheritance vector, parallel to $x^a$. We compare the outcome with the conditions of conformal Killing vectors. This comparison provides us the conditions for the existence of matter inheritance vector when it is also a conformal Killing vector. Finally, we discuss these results for the existence of matter inheritance vector in the special cases of the above mentioned spacetimes.Comment: 27 pages, accepted for publication in Int. J. of Mod. Phys.

Shape optimization of single- and two-element airfoils on multiblock grids

A multiblock, discrete sensitivity analysis method is used to couple a direct optimization method and a flow analysis method. The domain is divided into smaller subdomains for which the sensitivities are obtained separately. Then, an effective sensitivity equation is solved to complete the coupling of all the sensitivity information. The flow analysis is based on the thin-layer Navier-Stokes equations solved by an implicit, upwind-biased, finite-volume method. The method of feasible directions is used for the present gradient-based optimization approach. First, a transonic airfoil is optimized to investigate the behavior of the method in highly nonlinear flows as well as the effect of different blocking strategies on the procedure. A supercritical airfoil is produced from an initially symmetric airfoil with multiblocking affecting the path but not the final shape. Secondly, a two-element airfoil is shape optimized in subsonic flow to demonstrate the present method's capability of shaping aerodynamically interfering elements simultaneously. For a very low and a very high Reynolds number cases, the shape of the main airfoil and the flap are optimized to yield improved lift-to-drag ratios

Preparation of high surface area activated carbon from waste-biomass of sunflower piths: Kinetics and equilibrium studies on the dye removal

Sunflower pith (SP), a vast agricultural waste is herein used as a precursor material for highly porous low density activated carbon production. Porosity and flake-like microstructure of the SP in its natural form are shown by micro-computed tomography (Micro-CT). Carbonization process turns the SP into thin, separated carbon flakes of 200 nm thickness. Two types of alkaline based chemical activation with KOH and NaOH are performed to yield SP based activated carbon (AC), K-SPAC and N-SPAC, respectively. Microstructural changes upon carbonization and activation process are elaborated by RAMAN, FTIR and SEM analyses. BET Surface area of the NaOH-activated N-SPAC was calculated as 2690 m2/g and was higher than KOH-activated K-SPAC with 2090 m2/g. Maximum adsorption capacity of N-SPAC was calculated as 965 mg/g whereas it was 580 mg/g for K-SPAC. Adsorption kinetic studies for N-SPAC revealed that at a low initial concentration of dye (500 mg/L), the pseudo first-order kinetic model was predictive. On the other hand, at high initial MB concentration (1000 mg/L), the results indicate that the adsorption kinetics follow the Elovich model with intraparticle diffusion as one of the rate-determining steps. In conclusion, overall results suggest that thanks to its highly porous microstructure, the SP is an alternative renewable AC precursor choice for dye removal applications

Cultivation of Agaricus bisporus on wheat straw and waste tea leaves based composts and locally available casing materials Part III: Dry matter, protein, and carbohydrate contents of Agaricus bisporus

This study was performed to determine the effects of composts and casing materials on dry matter, protein, and carbohydrate contents of the fruit bodies of Agaricus bisporus. Results showed that Agaricus bisporus cultivated on group I and group II casing soil groups showed remarkably higher dry matter and carbohydrate contents compared to other casing groups. No significant differences were found among casing soil groups in terms of protein content of Agaricus bisporus cultivated on wheatstraw. But, there were significant differences between casing soil groups in terms of protein content of Agaricus bisporus cultivated on waste tea leaves

Yield response of mushroom (Agaricus bisporus) on wheat straw and waste tea leaves based composts using supplements of some locally available peats and their mixture with some secondary casing materials

The study was conducted to investigate yields of mushroom (Agaricus bisporus) on wheat straw and waste tea leaves based composts. Mixtures (50:50, v/v) of some locally available peats including peat ofBolu (PB), peat of Agacbasi (PA), peat of Caykara (PC) and their mixture (80:20; v/v) with which piece of mosaic and sand were used. Also, some activator materials such as wheat bran, wheat chaff, chickenmanure, pigeon manure, and poplar leaves were used for A. bisporus cultivation. The results on wheat straw based composts provided the highest mushroom yield (23.01%) that was obtained on wheat strawand pigeon manure based compost using a mixture of PA with PC (50+50; v/v) as casing material. For waste tea leaves based composts, the highest mushroom yield (24.90%) were recorded on wheat straw and pigeon manure based compost using a mixture of PC with sand (80+20; v/v) as casing material

Cultivation of Agaricus bisporus on wheat straw and waste tea leaves based compost formulas using wheat chaff as activator material

This study was designed to determine the pin head formation time and yield values of Agaricus bisporus on some casing materials. Composts were prepared basically from wheat straw and waste tea leaves by using wheat chaff as activator substance. Temperatures of the compost formulas were measured during composting at various depths in order to determine the compostability level. Results showed that in both compost types, maximum temperature values were recorded in the second turning stage. Composting was completed in 21 days for both composts. While the fastest pin head formation (12.50 days) was obtained on wheat straw based compost using peat of Bolu (PB) and peat of Agacbasi (PA) (50+50; in volume); waste tea leaves based compost using peat of Caykara (PC) and forest soil (FS) mixture (50+50; in volume) as casing material gave the fastest pin head formation (13.25 days). In terms of yield, a mixture of peat of Bolu and peat of Agacbasi (PA) (50+50; in volume) gave the highest yieldfor wheat straw based compost, a mixture of peat of Agacbasi and perlite (P) (80+20; involume) had the highest yield for waste tea leaves based compost

An investigation on pin head formation time of Agaricus bisporus on wheat straw and waste tea leaves based composts using some locally available peat materials and secondary casing materials

This study was designed to determine pin head formation time of Agaricus bisporus on wheat straw and waste tea leaves based composts. Locally available peat materials such as peat of Bolu (PB), peat of Agacbasi (PA), peat of Caykara (PC), and their mixture (80:20; v:v) with piece of mosaic (PM), perlite (P), and sand (S) were used as secondary casing materials. Also, some activator materials such aswheat bran, chicken manure, and pigeon manure were used for A. bisporus cultivation. For wheat straw based composts, the fastest pin head formation times were observed with a mixture of PA with PMcasing material on wheat straw and chicken manure based compost and with PA casing material on wheat straw and pigeon manure based compost. For waste tea leaves based composts, the fastest pinhead formation times were obtained with a mixture of PA with PM and PC with PM on waste tea leaves and chicken manure based compost. Generally, when peat materials were used in combination witheach other, the period of pin head formation times shortened compared to their individual use. A mixture of forest soil with sand (80 + 20; in volume) gave the worst results in terms of pin head formation times for both composts. In secondary casing materials, PM gave the best results in terms of pin head formation time for both composts

Cultivation of Agaricus bisporus on some compost formulas and locally available casing materials. Part II: Waste tea leaves based compost formulas and locally available casing materials

Three compost formulas (formula I, formula II, and formula III) based waste tea leaves and using some activator materials such as wheat bran, chicken manure and pigeon manure were studied for Agaricusbisporus cultivation. Some locally available peats such as peat of Bolu, peat of Agacbasi, peat of Caykara and theirs mixture (80:20; volume : volume) with perlite were used. Temperature values of allcompost formulas during composting process were measured to determine the compostability level. According to results, compost temparature steadily increased until the 8th, 9th, and 9th day ofcomposting for formula I, formula II, and formula III, respectively. The maximum compost temperature values were measured for all compost formulas at the second turning stage of composting process.The highest compost temperature values were measured prepared from a mixture of waste tea leaves and wheat bran (formula I). The best mushroom yield was obtained by a mixture of waste tea leaves andpigeon manure with the peat of Caykara and perlite mixture as casing material. Peat of Caykara gave higher mushroom yield than those of other peats