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Various additives are introduced to drilling mud to control its flow behavior in drilling operations under the desired conditions. These additives can cause increased drilling costs and environmental damage. In recent years, natural materials have mainly been used in drilling mud to reduce the increasing costs. In this study, amorphous silica was obtained by alkaline extraction method from pumice and quartzite, having a large reserve in Turkiye. Amorphous silica, which is cost-effective and easy to supply, was used in the drilling mud and rheological and filtration tests of the fluids. The results obtained from the study indicate that drilling mud with 8, 9, and 10 % of amorphous silica exhibits promising results.

The objective of the study is to design a drilling fluid that prevents differential pressure pipe sticking tendency caused by drilling fluid with fly ash that is an industrial waste generated from the combustion of coal. To this end, drilling fluid samples were prepared with different particle sizes obtained through the sieving and grinding process and increasing concentrations of fly ash. Differential pipe sticking tests of the samples were performed by applying 3.447 MPa (500 psi) pressure and using a Fann Model 21150 Differential Sticking Tester in order to determine how the coefficient of sticking and torque reading varied with the fly ash. From the results, it was observed that the coefficient of sticking and torque reading of the water-based drilling fluids decreased up to a specific concentration as the concentration of fly ash increased. Furthermore, particle size analysis illustrated that the coefficient of sticking and torque of the drilling fluid differs depending on the particle size of fly ash introduced. The drilling fluid designed with ground fly ash demonstrated lower sticking coefficient and torque reading than that of drilling fluids formulated with raw and sieved fly ashes. The experimental study revealed that fly ash is a promising additive in the mitigation of differential sticking tendency caused by water-based drilling fluids., Cilj je ovoga istraživanja pripremiti isplaku uz dodatak lebdećega pepela, koji je industrijski otpad dobiven izgaranjem ugljena, koja će spriječiti pojavu diferencijalnoga prihvata bušaćih alatki. Ispitani su uzorci isplake koji su pripremljeni s različitim koncentracijama i veličinama čestica lebdećega pepela, dobivenim mljevenjem i prosijavanjem. Ispitivanje sklonosti diferencijalnom prihvatu u različitim uzorcima isplake provedeno je pri tlaku 3,447 MPa (500 psi) korištenjem uređaja Fann Model 21150, pri čemu je praćena promjena koeficijenta ljepljivosti i očitanja torzije s dodavanjem lebdećega pepela. Iz rezultata je vidljivo da se koeficijent ljepljivosti i očitanje torzije smanjuju s povećanjem koncentracije lebdećega pepela u isplaci. Nadalje, istraživanje je pokazalo da i koeficijent ljepljivosti i torzija ovise o raspodjeli veličine čestica lebdećega pepela u isplaci. Isplaka pripremljena s mljevenim lebdećim pepelom pokazala je niži koeficijent prianjanja i manje očitanje torzije u odnosu na isplake pripremljene s nemljevnim („sirovim”) ili prosijanim lebdećim pepelom. Istraživanje je pokazalo da bi se lebdeći pepeo mogao koristiti kao aditiv za smanjenje sklonosti diferencijalnom prihvatu u isplakama na bazi vode.

Algae biomass could be one of the most important economic values in near future. For this reason, we determined the biochemical compositions and molecular weight profiles (MWPs) of eight macroalgae; Green Algae (Codium fragile, Ulva intestinalis, Chaetomorpha linum, and Codium bursa), Red Algae ( Ellisolandia elongata, Jania rubens, and Amphiroa rigida), Brown Algae (Padina pavonica) collected from different regions in Turkey. The differences measured between biochemical compositions such as ash, lipid, and protein of macroalgae species were statistically significant (P. The lowest levels of MWP belonging to the macroalgae was observed in 2532-13000 Da except for Ulva intestinalis and Padina pavonica belonging to 67000 Da were similar to each other except for Ulva intestinalis. The 13700 - 67000 Da and 2532-13000 Da levels belonging to Ulva intestinalis were higher than those of other tested macroalgae. However, level of Ulva intestinalis (67000 Da

Sargassurn vulgare was sampled by free dives in Iskenderun Bay, Hatay, Turkey, in September 2018. Sargassum vulgare is a material with high economic value because it has compounds that can be used in medical applications such as alginic acid and at the same time it contains carbohydrates and vitamins. Alginates were extracted with a sequential extraction protocol from Sargassum vulgare. Structural characterization of alginate obtained from Sargassum vulgare was determined by FT-IR spectrum, phase structure by XRD diffractometer, and surface morphology by SEM image. Within the scope of the study, alginate obtained from Sargassurn vulgare and herbal preservative 705 used in the field of cosmetics were compared. After pretreatment of Sargassurn vulgare with ethanol, alginate extraction was performed. Microorganisms of Pseudontonas aeruginosa, Staphylococcus aureus, Candida albicans, Escherichia soli, Aspergillus brasiliensis were used to examine the antimicrobial activity of the obtained alginate and showed that the contamination risk was tolerable for all microorganisms examined on the seventh day of incubation. Alginate obtained from Sargassum vulgare was found to be more effective than herbal preservative 705 at 0 hours. Pseudomonas aeruginosa, Staphylococcus aureus are microorganisms with the highest effect in the 0 hour. Since alginate obtained from Sargassurn vulgare is more effective on microorganisms in a shorter time than herbal preservative 705, it is predicted that it can be a product that can be used in the field of cosmetics.

In this work, Bi2Ca2-xNaxCo2Oy with x = 0.0, 0.05, 0.10, and 0.125 thermoelectric ceramic materials have been produced by the classical solid-state route, followed by texturing through the laser floating zone (LFZ) method. All specimens showed similar XRD patterns, with the main peaks corresponding to the (00l) plane reflections of the thermoelectric Bi2Ca2Co2Oy phase, independently of Na substitution. In addition, small amount of Co-free Ca4Bi6O13 secondary phase has been identified. SEM micrographs showed that annealing procedure after the texturing process allows obtaining higher proportion of thermoelectric phase, decreasing the number and amount of secondary phases. Electrical resistivity is very similar for all samples at room temperature, about 0.62 mΩ m. However, below 50 K, Na-substitution decreases resistivity when compared to the undoped one, reaching values around 9.41, 6.48, 5.00, and 2.07 mΩ m for x = 0, 0.05, 0.1, and 0.125 samples at 50 K, respectively. Seebeck coefficient values at room temperature decrease from 180 to 145 μV/K, for the pure and 0.125Na doped samples, respectively. Thermal conductivity tends to linearly increase with temperature up to around 200 K, decreasing for higher ones. Thermal conductivity values are slightly higher in undoped samples (1.2 W/K m), when compared to the Na-substituted ones (1.10–1.30 W/K m) at room temperature. Finally, the highest ZT value is around 0.018 at 400 K for the 0.10Na doped samples., This study was carried out within the scope of Cukurova University Scientific Research Projects Unit FBA-2020-13007. A. Sotelo and M. A. Madre wish to thank the Spanish MINECO-FEDER (MAT2017-82183-C3-1-R), and Gobierno de Aragón (Research Group T54-20R) for funding.

The objective of this study is to develop a water-based drilling fluid with enhanced rheological and filtation characteristics by using a coal combustion by product which is known as fly ash (CCA). To this end, initially, bentonite drilling fluids were designed by CCA in various concentrations considering American Petroleum Institute (API) standards. Secondly, drilling fluid systems containing different concentration of bentonite and Xanthan Gum (XG) were prepared to analyze the effectiveness of CCA in different drilling mud compositions. In addition, the drilling fluid samples containing bentonite in the presence and absence of CCA were aged under different periods for a better analyzing the performance of CCA. Experimental outcomes showed that improvement in the drillling fluid depends on concentration of CCA introduced and developed drilling fluid systems containg increasing bentonite and XG concentration in presence of CCA had better rheological behaviour. In addition, aging time also enhanced the rheological behaviour of the developed drilling fluid containing CCA. Through the study, a cost effective water based drilling fluid possessing superior characteristics was developed by CCA, thereby decrasing possibility of serious drilling problems and cost of drilling operatio

This study investigates the possibility of using rice husk ash as an additive to develop an environmentally friendly and low-cost drilling fluid system. Rice husk ash was added as an additive to water-based bentonite drilling fluids at different concentrations ranging from 2 wt% to 15 wt%. The rheological and filtration properties of each developed drilling fluid were measured by using a viscometer and standard low-pressure low-temperature filter press. Subsequently, the cutting carrying index, the minimum annulus velocity required to clean the bottom of the well efficiently, the flow behaviour index and the permeability of mud cakes of the formulated systems were calculated in order to assess the performance of the systems. The results demonstrated that the rheological and properties were improved depending on the concentration of the rice husk ash introduced. With the introduction of 15 wt% concentration of rice husk ash, while apparent viscosity and yield point increased by 60% and 183%, respectively, thixotropy and plastic viscosity decreased by 29% and 63%, respectively. On the other hand, drilling fluid with 4% wt% content of rice husk ash reduced the fluid loss by 10%. Moreover, the results showed that cutting the carrying index, the minimum annulus velocity required to clean the bottom of the well efficiently and the flow behaviour index of the enhanced with the exploitation of the rice husk ash in the drilling fluid. This study showed that rice husk ash is a promising additive to use in water-based bentonite drilling fluids when properly implemented, and hence reduces the impact on the environment, and the total cost for drilling., Istražene su mogućnosti upotrebe pepela rižine ljuske kao aditiva za pripremu ekološki prihvatljivijih i jeftinijih isplaka. Pepeo rižine ljuske dodan je u bentonitnu isplaku u različitim koncentracijama u rasponu od 2 do 15% maseno. Reološka i filtracijska svojstva pripremljenih isplaka mjerena su upotrebom viskozimetra i standardne API filtar preše. Naknadno, kako bi se bolje procijenila svojstva ispitivanih isplaka određen je indeks iznošenja krhotina, minimalna brzina protjecanja isplake u prstenastome prostoru potrebna za efikasno čišćenje dna bušotine, indeks toka te propusnost isplačnoga obloga. Dobiveni rezultati upućuju na poboljšanje reoloških i ostalih svojstava ispitivanih isplaka u ovisnosti o korištenoj koncentraciji pepela rižine ljuske. Kod isplake u koju je dodano 15% maseno pepela rižine ljuske uočeno je povećanje prividne viskoznosti za 60% i naprezanja pri pokretanju za 183%, dok su tiksotropna svojstva i plastična viskoznost smanjeni za 29 % odnosno 63%. S druge strane, kod isplaka koje su pripremljene s 4% maseno pepela rižinih ljuski izmjereno je smanjenje filtracije za 10 %. Štoviše, rezultati upućuju na poboljšanje indeksa iznošenja krhotina, smanjenje minimalne vrijednosti brzine protoka u prstenastome prostoru za efikasno čišćenje dna bušotine i vrijednosti indeksa toka kod upotrebe pepela rižinih ljuski u isplaci. Ovo istraživanje jasno pokazuje da je pravilnom primjenom pepela rižinih ljuski kao aditiva u bentonitnoj isplaci moguće smanjiti utjecaj na okoliš i troškove bušenja.

Hydroxyapatite and associated calcium phosphate ceramic materials are commonly applied as implant resources because of their close resemblance in structure with natural bone. In the present study, the elemental composition and potential usage of pufferfish teeth were examined as natural bioceramic for dental applications. The teeth of pufferfish Lagocephalus sceleratus were removed from the fish, rinsed with deionized water, measured, and kept in the furnace at 105 degrees C. The dehydrated teeth were pulverized with the planetary ball. ICP-MS, TTX, XRD, and nanoindentation test analyzes were made on the obtained hydroxyapatite. In the ICP-MS analysis, the elemental composition of the teeth was 52% calcium, 39% phosphate, %2.5 Mn, %1.5 Mg, %1 Ti, %0.8 V, and %3.2 the others. Ca/P atomic ratio value was 1.32. The present study preliminary revealed that the use of pufferfish teeth can be a natural alternative source for biomedical and other industrial purposes since it has no economic value and is very abundant in the world marine waters. On the other hand, the required tests are mandatory to be accomplished before any human use.