Polycyclic aromatic hydrocarbons (PAHs), due to their mutagenic, carcinogenic, and teratogenic potential, can lead to numerous chronic and fatal diseases. PAHs have been found in several wastewater streams, including “produced water,” which is wastewater generated during the extraction of oil and gas. The PAHs’ removal from produced water using physical, chemical, biological, and combined methods is crucial. Water is a vital ecosystem component and is extremely vulnerable to PAHs. This article reviews the current PAH situation, including their physical and chemical properties, types, characteristics, and removal methods from produced water. The mechanism of each method of removal of PAHs has been discussed. The current study results show that adsorption by nanoparticles and integrated methods are promising methods to meet the strict authoritarian limit with advanced increase potential in the direction of commercialization for the removal of PAHs and provide opportunities to use produced water as a source of water. The current study results can help the policy/decision makers in the efficient management of water resources.

Beam–column connections are the most critical components of reinforced concrete (RC) structures. They serve as a load transfer path and take a significant portion of the overall shear. Joints in RC structures constructed with no seismic provisions have an insufficient capacity and ductility under lateral loading and can cause the progressive failure of the entire structure. The joint may fail in the shear prior to the connecting beam and column elements. Therefore, several modeling techniques have been devised in the past to capture the non-linear response of such joints. Modeling techniques used to capture the non-linear response of reinforced-concrete-beam–column joints range from simplified lumped plasticity models to detailed fiber-based finite element (FE) models. The macro-modeling technique for joint modeling is highly efficient in terms of the computational effort, analysis time, and computer memory requirements, and is one of the most widely used modeling techniques. The non-linear shear response of the joint panel and interface bond–slip mechanism are concentrated in zero-length linear and rotational springs while the connecting elements are modeled through elastic elements. The shear response of joint panels has also been captured through rigid panel boundary elements with rotational springs. The computational efficiency of these models is significantly high compared to continuum models, as each joint act as a separate supe-element. This paper aims to provide an up-to-date review of macro-modeling techniques for the analysis and assessment of RC-beam–column connections subjected to lateral loads. A thorough understanding of existing models is necessary for developing new mechanically adequate and computationally efficient joint models for the analysis and assessment of deficient RC connections. This paper will provide a basis for further research on the topic and will assist in the modification and optimization of existing models. As each model is critically evaluated, and their respective capabilities and limitations are explored, it should help researchers to improve and build on modeling techniques both in terms of accuracy and computational efficiency.

Phosphorus (P) fractionation is the validation of the nature, solubility and relative bioavailability of P. A sequential P extraction was used to determine the distribution of plant-available P fractions in soils. The relationships of these P fractions to soil properties and foliar P contents were also determined. Results of this study showed substantial differences in soil properties among orchards. Higher amounts of soil organic matter (SOM), cation exchange capacity (CEC) and major plant nutrients were found under orchard soils when compared with control soil. Most of the soil variables varied among orchard species as loquat > citrus > guava. The orchard soil exhibited a slightly higher soil pH. Overall, the P fractions were higher in all types of orchard soils and lowered in the control soils. Among tree species, P fractions in soils were achieved as loquat > citrus > guava. The extracting agents differed for P in the order residual P > HCl-P > NaOH-P > NaHCO₃-P > H₂O-P. Mostly higher amounts of the P fractions were achieved in the topsoil. The average amount of extractable P was found significantly higher in those soils of fruit orchards where the total amount of P was actually higher. The higher r² values between P fractions versus SOM, clay and CEC of soils predicted a strong interrelationship among these soil variables. Leaf N contents of loquat and guava trees were consistently higher, and leaf P contents varied as loquat > citrus > guava. Potassium and Ca contents were higher in citrus than in the other two species. Micronutrients were found as Fe > Zn > Mn > Cu in the leaves. Regression models indicated a sufficient relationship between Hedley P fractions and the foliar P contents in tree species. This study indicates that the above soil properties can be used to ascertain soil P fractions, and that can influence the bioavailability of P from orchard soils.

This research work mainly focuses on improving the concrete strength based on fiber reinforcement both in compression and tension. Concrete with various mix proportions containing dosage of Polypropylene (PP) fiber of lengths ranging from 13 to 25 mm with coarse aggregate replacement levels at 10%, 20%, and 30% by dismantled road aggregate were made and the compressive and tensile strengths were investigated. The experimental test results revealed high compressive and tensile strength at curing period of 28 and 56 days. The specimens tested observed that due to addition of fiber, the fibers could hold the matrix together even after extensive cracking and crushing. Net result of all these is to impart to the fiber composite pronounced post-cracking ductility which is absent in traditional concrete. In order to provide base for comparison, concrete specimens as a reference were cast without the addition of polypropylene fiber. Test result revealed that by adding polypropylene fibers at 6grams per one kg of cement a considerable improvement in the strength of concrete of 37.68 MPa and 43.59 MPa at 28 and 56 days respectively with 10% coarse aggregate replacement by recycled aggregate is achieved. Streszczenie: W artykule przedstawiono badania, których celem było zwiększenie wytrzymałości betonu na ściskanie i rozciąganie przed dodatek zbrojenia rozproszonego w postaci włókien polipropylenowych. W badaniach wytrzymałości na ściskanie i rozciąganie próbek betonowych stosowano różnorodne mieszanki betonowe z dodatkiem włókien polipropylenowych (PP) o długościach od 13 do 25 mm i z dodatkiem kruszywa wtórnego pochodzącego z rozbiórki nawierzchni drogowych zastępującego kruszywo grube w ilościach: 10%, 20% i 30%. W badaniach, po 28. i 56. dniach twardnienia betonu, uzyskano wysoką wytrzymałość na ściskanie i rozciąganie. Dzięki dodatkowi włókien zaobserwowano, że matryca cementowa jest utrzymana nawet wówczas, gdy ma miejsce intensywne zarysowanie i zmiażdżenie próbki. W badaniach stwierdzono zatem ciągliwość po zarysowaniu kompozytu betonowego zbrojonego włóknami, której pozbawiony jest tradycyjny beton. Do badań porównawczych, wykonano próbki betonowe bez dodatku włókien polipropylenowych. W badaniach porównawczych, dzięki dodatkowi włókien polipropylenowych w ilości 6 g/kg cementu uzyskano znaczną poprawę wytrzymałości betonu – o 37.68 MPa i 43.59 MPa, odpowiednio po 28. i 56. dniach i przy 10% zastąpieniu kruszywa grubego kruszywem drogowym, z recyklingu.