A review of technological advances and open challenges for oil and gas drilling systems engineering

The ever‐increasing quest to identify, secure, access and operate oil and gas fields is continuously expanding to the far corners of the planet, facing extreme conditions towards exploring, securing and deriving maximum fluid benefits from established and unconventional fossil fuel sources alike: to this end, the unprecedented geological, climatic, technical and operational challenges have necessitated the development of revolutionary drilling and production methods. This review paper focuses on a technological field of great importance and formidable technical complexity ‐ that of well drilling for fossil fuel production. A vastly expanding body of literature addresses design and operation problems with remarkable success: what is even more interesting is that many recent contributions rely on multidisciplinary approaches and reusable Process Systems Engineering (PSE) methodologies ‐ a drastic departure from ad hoc/one‐use tools and methods of the past.The specific goals of this review are to first, review the state of art in active fields within drilling engineering, and explore currently pressing technical problems, which are in dire need, or have recently found, PSE‐and/or CFD‐relevant solutions. Then, we illustrate the methodological versatility of novel PSE‐based approaches for optimization and control, with an emphasis on contemporary problems. Finally, we highlight current challenges and opportunities for truly innovative research contributions, which require the combination of best‐in‐class methodological and software elements in order to deliver applicable solutions of industrial importance

Gene Expression-Based Cancer Classification for Handling the Class Imbalance Problem and Curse of Dimensionality

Cancer is a leading cause of death globally. The majority of cancer cases are only diagnosed in the late stages of cancer due to the use of conventional methods. This reduces the chance of survival for cancer patients. Therefore, early detection consequently followed by early diagnoses are important tasks in cancer research. Gene expression microarray technology has been applied to detect and diagnose most types of cancers in their early stages and has gained encouraging results. In this paper, we address the problem of classifying cancer based on gene expression for handling the class imbalance problem and the curse of dimensionality. The oversampling technique is utilized to overcome this problem by adding synthetic samples. Another common issue related to the gene expression dataset addressed in this paper is the curse of dimensionality. This problem is addressed by applying chi-square and information gain feature selection techniques. After applying these techniques individually, we proposed a method to select the most significant genes by combining those two techniques (CHiS and IG). We investigated the effect of these techniques individually and in combination. Four benchmarking biomedical datasets (Leukemia-subtypes, Leukemia-ALLAML, Colon, and CuMiDa) were used. The experimental results reveal that the oversampling techniques improve the results in most cases. Additionally, the performance of the proposed feature selection technique outperforms individual techniques in nearly all cases. In addition, this study provides an empirical study for evaluating several oversampling techniques along with ensemble-based learning. The experimental results also reveal that SVM-SMOTE, along with the random forests classifier, achieved the highest results, with a reporting accuracy of 100%. The obtained results surpass the findings in the existing literature as well

Coordination versatility of tridentate pyridyl aroylhydrazones towards iron : tracking down the elusive aroylhydrazono-based ferric spin-crossover molecular materials

The two potentially tridentate and monoprotic Schiff bases acetylpyridine benzoylhydrazone (HL 1) and acetylpyridine 4-tert-butylbenzoylhydrazone (HL 2) demonstrate remarkable coordination versatility towards iron on account of their propensity to undergo tautomeric transformations as imposed by the metal centre. Each of the pyridyl aroylhydrazone ligands complexes with the ferrous or ferric ion under strictly controlled reaction conditions to afford three six-coordinate mononuclear compounds [Fe II (HL) 2] (ClO 4) 2, [Fe II L 2] and [Fe III L 2] ClO 4 (HL = HL 1 or HL 2) displaying distinct colours congruent with their intense CT visible absorptions. The synthetic manoeuvres rely crucially on the stoichiometry of the reactants, the basicities of the reaction mixtures and the choice of solvent. Electrochemically, each of these iron compounds exhibits a reversible metal-centred redox process. By all appearances, [Fe III (L 1) 2]ClO4 is one of only two examples of a crystallographically elucidated iron(III) bis-chelate compound of a pyridyl aroylhydrazone. Several pertinent physical measurements have established that each of the Schiff bases stabilises multiple spin states of iron; the enolate form of these ligands exhibits greater field strength than does the corresponding neutral keto tautomer. To the best of our knowledge, [Fe III (L 1) 2]ClO 4 and [Fe III (L 2) 2 ]ClO 4 are the first examples of ferricspin crossovers of aroylhydrazones. Whereas in the former the spin crossover (SCO) is an intricate gradual process, in the latter the 6 A 1 ↔ 2 T 2 transition curve is sigmoidal with T 1 2 ~ 280 K and the SCO is virtually complete. As regards [Fe III (L 1) 2]ClO 4, M̈ossbauer and EPR spectroscopic techniques have revealed remarkable dependence of the spin transition on sample type and extent of solvation. In frozen MeOH solution at liquid nitrogen temperature, both iron(III) compounds exist wholly in the doublet ground state