Inadequate hole cleaning can lead to many problems in horizontal and directional wells. In this work, we tried to investigate the cutting transport phenomenon by an experimental directional drilling simulator, considering the differences between the operational and experimental conditions. The inclination, fluid type (water, foam, viscous, and dense), rotary speed (0 and 110 rpm), nozzle bit si...

 Production data analysis techniques have been widely used for estimating reservoir properties such as gas in place and average pressure. Knowledge of this information is crucial for proper reservoir management. The present study discusses the roadmap, challenges and uncertainties for analyzing production data in an Iranian gas-condensate offshore field. This work is an integrated study in...

Binary manipulators are powered by actuators which have only two stable states. Therefore, they can reach only a discrete (but possibly large) number of locations. Compared to a manipulator built with continuous actuators, a binary manipulator provides reasonable performance, and is relatively inexpensive (up to an order of magnitude cheaper). The number of states of a binary manipulator grows ...

In this paper, we study the existence of solution of the four-point boundary value problem for second-order differential equations with impulses by using leray-Schauder theory: ⎧⎨ ⎩ x′′(t) = f(t, x(t), x′(t)), t ∈ [0, 1], t = tk, k = 1, 2,··· ,m Δx(tk) = Ik(x(tk)), k = 1, 2,··· ,m Δx′(tk) = Ik(x(tk), x ′(tk)), k = 1, 2,··· ,m x′(0) = αx′(ξ), x(1) = βx(η), (E) where 0 < ξ ≤ η < 1, α ≥ 0, β ≥ 0 a...

The shift to modularized cars leads to the need for early and precise concept decisions for the development of modules. Many module definitions focus on the interaction between modules to make them upgradeable. The focus here is on modules that have to work with unknown restrictions in terms of uncertainty. In this paper, emphasis is put on unknown car styling in early design stages. Because of...

Abstract. Let Rk(n) be the number of representations of an integer n as the sum of a prime and a k-th power for k ≥ 2. Furthermore, set Ek(X) = |{n ≤ X, n ∈ Ik, n not a sum of a prime and a k-th power}|. In the present paper we use sieve techniques to obtain a strong upper bound on Rk(n) for n ≤ X with no exceptions, and we improve upon the results of A. Zaccagnini to prove Ek(X) ≪k X 1−181 log...

A complete proof of the quark Reggeization hypothesis in the leading logarithmic approximation for any quark–gluon inelastic process in the multi–Regge kinematics in all orders of α s is given. First, we show that the multi–Regge form of QCD amplitudes is guarantied if a set of conditions on the Reggeon vertices and the trajectories is fulfilled. Then, we examine these conditions and show that ...

We report exact black hole solutions in asymptotically flat or (A)dS four-dimensional spacetime with a conformally coupled self-interacting scalar field $f(R)$ gravity. first consider the model $f(R) = R -2\alpha \sqrt{R}$ and derive an solution. Then, we =R -2 \Lambda \alpha \sqrt{R-4 }$ In both cases modified gravity parameter $\alpha$, which has dimension of inverse mass, cannot be set to ze...