Challenges and Lessons Learnt on Waste Management and Disposal from Mauritania Deepwater Abandonment and Decommissioning Campaign

Abandonment and decommissioning activities of oil and gas assets had been on the increasing trend. As an activity of minimal to no economic value return, the investment into Abandonment and Decommissioning (A&D) should be properly strategized to ensure all objectives are met safely within available time and resources. This paper will discuss Operator's strategy in planning and handling waste from A&D activities of fifteen (15) deepwater subsea wells in Mauritania, West Africa. The approach of this A&D project at a remote location was done in two separate campaign instead of a single campaign based on technical and commercial evaluations performed by Operator. Subsea structures, Christmas trees, tubulars and others are expected to be retrieved and disposed according to local and international standard. In general, Operator are expecting two (2) type of waste which are non-hazardous waste and hazardous waste due to hydrocarbon or naturally occurring radioactive material (NORM) contamination. Due to the limitation of capable hazardous waste handling and disposal in country, Operator decided to export waste to identified facilities outside of country at the end of the project via sea-freight. Operator appointed one contractor to provide a full-service related to the waste management and disposal that covers field services and onshore services that includes radiological monitoring to identify NORM waste, labelling, packaging at offshore, onshore storage, transportation and logistics that include Trans-Frontier Shipment (TFS). The strategy of appointing one contractor for full service of waste management and disposal has promoted a single – point accountability to the contractor and this has enabled the objective been delivered effectively. COVID-19 pandemic posed a great challenge on cross-border logistic planning due to additional measure been imposed by receiving country. Furthermore, the new development of United Kingdom exiting European Union (BREXIT) also posed some level of uncertainty to the contractor to obtain relevant approvals for waste export. To reduce the amount of waste to be export, Operator continuously looking for and successfully found a local recycling facility that able to handle the non-hazardous waste while meeting local regulation, Operator's and industrial standard. All outlined strategy was proven to be effective for waste management in remote location, uncertainty on cross-border waste export challenge, as well as capitalizing on the limited local resources available.

Global Well-Posedness for the Fractional Navier-Stokes-Coriolis Equations in Function Spaces Characterized by Semigroups

We studies the initial value problem for the fractional Navier-Stokes-Coriolis equations, which obtained by replacing the Laplacian operator in the Navier-Stokes-Coriolis equation by the more general operator $(-\Delta)^\alpha$ with $\alpha>0$. We introduce function spaces of the Besove type characterized by the time evolution semigroup associated with the general linear Stokes-Coriolis operator. Next, we establish the unique existence of global in time mild solutions for small initial data belonging to our function spaces characterized by semigroups in both the scaling subcritical and critical settings.

A GENERALIZATION OF THE SHIFT OPERATOR

Several approaches are known to generalize the shift operator in the complex domain. Specific generalization procedures lead to significantly different operators of the shift type even in one specific area of complex analysis. In this paper, a certain general operator of the shift type is defined. The properties of this operator are studied and the question of the continuity of this definition is considered. The properties of a certain operator to a certain extent re-peat the properties of the previously studied operators of the shift type. This allows us to speak of the possibility of extending the main results on spectral synthesis in the complex domain to convolutional equations of a more general form.

Quantum reference frames for general symmetry groups

A fully relational quantum theory necessarily requires an account of changes of quantum reference frames, where quantum reference frames are quantum systems relative to which other systems are described. By introducing a relational formalism which identifies coordinate systems with elements of a symmetry group G, we define a general operator for reversibly changing between quantum reference frames associated to a group G. This generalises the known operator for translations and boosts to arbitrary finite and locally compact groups, including non-Abelian groups. We show under which conditions one can uniquely assign coordinate choices to physical systems (to form reference frames) and how to reversibly transform between them, providing transformations between coordinate systems which are `in a superposition' of other coordinate systems. We obtain the change of quantum reference frame from the principles of relational physics and of coherent change of reference frame. We prove a theorem stating that the change of quantum reference frame consistent with these principles is unitary if and only if the reference systems carry the left and right regular representations of G. We also define irreversible changes of reference frame for classical and quantum systems in the case where the symmetry group G is a semi-direct product G=N⋊P or a direct product G=N×P, providing multiple examples of both reversible and irreversible changes of quantum reference system along the way. Finally, we apply the relational formalism and changes of reference frame developed in this work to the Wigner's friend scenario, finding similar conclusions to those in relational quantum mechanics using an explicit change of reference frame as opposed to indirect reasoning using measurement operators.

Competition phenomena for elliptic equations involving a general operator in divergence form

In this paper, by using variational methods, we study the following elliptic problem [Formula: see text] involving a general operator in divergence form of [Formula: see text]-Laplacian type ([Formula: see text]). In our context, [Formula: see text] is a bounded domain of [Formula: see text], [Formula: see text], with smooth boundary [Formula: see text], [Formula: see text] is a continuous function with potential [Formula: see text], [Formula: see text] is a real parameter, [Formula: see text] is allowed to be indefinite in sign, [Formula: see text] and [Formula: see text] is a continuous function oscillating near the origin or at infinity. Through variational and topological methods, we show that the number of solutions of the problem is influenced by the competition between the power [Formula: see text] and the oscillatory term [Formula: see text]. To be precise, we prove that, when [Formula: see text] oscillates near the origin, the problem admits infinitely many solutions when [Formula: see text] and at least a finite number of solutions when [Formula: see text]. While, when [Formula: see text] oscillates at infinity, the converse holds true, that is, there are infinitely many solutions if [Formula: see text], and at least a finite number of solutions if [Formula: see text]. In all these cases, we also give some estimates for the [Formula: see text] and [Formula: see text]-norm of the solutions. The results presented here extend some recent contributions obtained for equations driven by the Laplace operator, to the case of the [Formula: see text]-Laplacian or even to more general differential operators.

Solving Operator Equation Based on Expansion Approach

To date, researchers usually use spectral and pseudospectral methods for only numerical approximation of ordinary and partial differential equations and also based on polynomial basis. But the principal importance of this paper is to develop the expansion approach based on general basis functions (in particular case polynomial basis) for solving general operator equations, wherein the particular cases of our development are integral equations, ordinary differential equations, difference equations, partial differential equations, and fractional differential equations. In other words, this paper presents the expansion approach for solving general operator equations in the form Lu+Nu=g(x),x∈Γ, with respect to boundary condition Bu=λ, where L, N and B are linear, nonlinear, and boundary operators, respectively, related to a suitable Hilbert space, Γ is the domain of approximation, λ is an arbitrary constant, and g(x)∈L2(Γ) is an arbitrary function. Also the other importance of this paper is to introduce the general version of pseudospectral method based on general interpolation problem. Finally some experiments show the accuracy of our development and the error analysis is presented in L2(Γ) norm.