Alkali-Silica. Reaction Of Foamed. Concrete Containing. Waste Glass as Aggregate

This research focused on examining Alkali-Silica. Reaction (ASR) of foamed concrete mixes containing1different1types of1crushed waste glass (CWG) with different chemical compositions. The reactivity was determined in sodium hydroxide solution by adopting mortar bar test. Four types of waste glass with different particle sizes and different percentages content were used. From the test results of recorded expansion of these mixes, it was noticed that the coarse glass resulted in more expansion than that of fine glass. Lead-silicate1glass (CR) exhibits the maximum expansion followed by1soda-lime1glass (SL) and boro-silicate glass (BS), while less expansion was recorded in mixes with green glass (GG). As compared to reference mix (FC), it was noted that the mixes with crushed waste glass (SL), (BS), and (CR) undergo notable expansion, while the expansion of the mixes with (GG) slightly increased compared to the reference mix (FC).

Stakeholder Requirements for Reporting Information and Digital Technologies

The modern system of accounting and reporting is in the process of reforming, and a particularly important component of the reform is the modifi cation of fi nancial reporting, since on its basis decisions are made on the development of the economic system by investors and other stakeholders, namely: the maximum expansion of the circle of information users; presentation of information related to the implementation of the planning function; provision of non-financial reporting refl ecting the value of the organization and preparation of non-fi nancial reporting; reflection of financial information on human capital, brands, innovation, provision of fi nancial environmental and social reporting; formation of general user orientation of fi nancial statements.

Pushing the Limits for Open Hole Zonal Isolation – Design and Qualification of Expandable Steel Packer

Enhancing gas productivity is linked to multistage stimulation (MSS). Choosing a cemented over uncemented solution is driven by factors such as operational efficiency, drilling practices, and isolation techniques. Swellable and mechanical packers have been used widely. A new packer type, an expandable steel packer, has been qualified recently, the expandable steel packer combines the strengths of mechanical and swellable packers and will provide an option for openhole completions. The 4.5-in. expandable steel packer design was optimized to meet most demanding applications with the following characteristics: reduced running outside diameter (OD) to 5.6 in., premium assembly technique by crimping, double sleeve pressure self-compensation, and use of nickel alloys for sour environment. After the design of the packer was completed, the 4.5-in. expandable steel packer was qualified according to the API Spec 19OH (API 2018) standard protocol at 15,000 psi with thermal variation between 320°F and 68°F. The packer was tested in a casing with inside diameter (ID) of 6.5 in. The test casing had an ID of 6.5 in. whereas nominal hole size ranges from 5.875 in. to 6.125 in. It was chosen to simulate a washout and considering the calculated maximum expansion ratio for the steel to verify the 15,000-psi pressure rating capability. The test casing was built with a heat exchanger, high-pressure pump, and pressure and temperature sensors. The packer was expanded inside the dummy well with all the measuring instruments in place. Expansion pressure signatures were observed as predicted. The analysis of the packer setting pressure curves showed expansion initiation and full casing ID contact. The liquid differential pressure test from each side of the packer proved the internal pressure compensation performed as expected. No leak was observed during the pressure steps of 15.000 psi held for 15 minutes while cycling the temperature from 320°F to 68°F and back to 320°F. The expandable steel packer utilizes a unique double-sleeve system for self-pressure compensation during ball-drop stimulation operations. The packer expandable sleeve is protected during deployment by the end fittings. Expandable steel packers exhibit robustness during running in hole, enable setting on demand, have a high expansion ratio, require no de-rating vs. hole size, and have low sensitivity to thermal variations.

Life Augmentation of Turbine Exhaust System Compensators Through Integrated MADM Optimization Approach of Stress Based Fatigue Cycles

Exhaust expansion joints, also known as compensators, are found in a variety of applications such as gas turbine exhaust pipes, generators, marine propulsion systems, OEM engines, power units, and auxiliary equipment. The motion compensators employed must have accomplished the maximum expansion-contraction cycle life while imposing the least amount of stress. Discrepancies in the selecting of bellows expansion joint design parameters are corrected by evaluating stress-based fatigue life, which is challenging owing to the complicated form of convolutions. Meridional and circumferential convolution stress equations that influencing fatigue cycles are evaluated and verified with FEA. Fractional factorial Taguchi L25 matrix is used for finding the optimal configurations. The discrete design parameters for the selection of the suitable configuration of the compensators are analysed with the help of the MADM decision making techniques. The multi-response optimization methods GRA, AHP, and TOPSIS are used to determine the parametric selection on a priority basis. It is seen that weighing distribution among the responses plays an important role in these methods and GRA method integrated with principal components shows best optimal configurations. Multiple regression technique applied to these methods also shows that PCA-GRA gives better alternate solutions for the designer unlike the AHP and TOPSIS method. However, higher ranked Taguchi run obtained in these methods may enhance the suitable selection of different design configurations. Obtained PCA-GRG values by Taguchi, Regression and DOE are well matched and verified for the all alternate solutions. Further, it also shows that stress based fatigue cycles obtained in this analysis for the L25 run indicates the range varying from 1.13 × 104 cycles to 9.08 × 105 cycles, which is within 106 cycles. This work will assist the design engineer for selecting the discrete parameters of stiff compensators utilized in power plant thermal appliances.

Wall shear stress from jetting cavitation bubbles: influence of the stand-off distance and liquid viscosity

We study systematically the cavitation-induced wall shear stress on rigid boundaries as a function of liquid viscosity $\mu$ and stand-off distance $\gamma$ using axisymmetric volume of fluid (VoF) simulations. Here, $\gamma =d/R_{max}$ is defined with the initial distance of bubble centre from the wall $d$ and the bubble equivalent radius at its maximum expansion $R_{max}$ . The simulations predict accurately the overall bubble dynamics and the time-dependent liquid film thickness between the bubble and the wall prior to the collapse. The spatial and temporal wall shear stress is discussed in detail as a function of $\gamma$ and the inverse Reynolds number $1/Re$ . The amplitude of the wall shear stress is investigated over a large parameter space of viscosity and stand-off distance. The inward stress is caused by the shrinking bubble and its maximum value $\tau _{mn}$ follows $\tau _{mn} Re^{0.35}=-70\gamma +110$ (kPa) for $0.5<\gamma <1.4$ . The expanding bubble and jet spreading on the boundary produce an outward-directed stress. The maximum outward stress is generated shortly after impact of the jet during the early spreading. We find two scaling laws for the maximum outward stress $\tau _{mp}$ with $\tau _{mp} \sim \mu ^{0.2} h_{jet}^{-0.3} U_{jet}^{1.5}$ for $0.5\leq \gamma \leq 1.1$ and $\tau _{mp} \sim \mu ^{-0.25} h_{jet}^{-1.5} U_{jet}^{1.5}$ for $\gamma \geq 1.1$ , where $U_{jet}$ is the jet impact velocity and $h_{jet}$ is the distance between lower bubble interface and wall prior to impact.

Success and complication rate of miniscrew assisted non-surgical palatal expansion in adults - a consecutive study using a novel force-controlled polycyclic activation protocol

Introduction Bone-borne miniscrew assisted palatal expansion (MAPE) is a common technique to improve maxillary transverse deficiency in young adolescents. Adult patients usually present a challenge, as they often require additional surgical assisted maxillary expansion (SARPE). There is still no clear statement about non-surgical expansion in adult patients using this technique. The aim of this study was to evaluate the success and complication rate of non-surgical palatal expansion in adults utilizing MAPE with a novel force-controlled polycyclic expansion protocol (FCPC). Methods This consecutive study consisted of 33 adult patients with an average age of 29.1 ± 10.2 years (min. 18 years, max. 58 years), including one dropout patient. First, four miniscrews were inserted and after 12-weeks latency, the expander was placed and the FCPC protocol was applied (MAPE group). In case of missing expansion, a SARPE was performed (SARPE group). After maximum expansion, a cone beam CT was made and widening of the midpalatal suture was measured. The outcome variables were successful non-surgical expansion and, with sample size power above 80%, the odds of failed non-surgical expansion and associated complications were evaluated. The primary predictor variable was age. Statistical analysis was performed using R (Version 3.1) to calculate power, to construct various models for measuring the odds of requiring surgical intervention/complications, and others. Results Successful non-surgical expansion was achieved in 27 patients (84.4%), ranging from 18 to 49 years. Mean age differed significantly between both groups (26.8 ± 8.2 years vs. 41.3 ± 9.9 years; p < 0.001). Mean expansion at the anterior and posterior palate for the MAPE group was 5.4 ± 1.5 mm and 2.5 ± 1.1 mm, respectively. Among these subjects’ complications were observed in 18.5%. Age significantly increased the odds of complications (p = 0.019). Conclusions 1. The success rate of MAPE among individuals aged 18 to 49 years was 84.4%. 2. A V-shaped expansion pattern in the antero-posterior dimension was mostly observed. 3. Complications were significantly associated with age. 4. A careful expansion protocol seems to be beneficial to prevent unfavorable results in adult patients. Trial registration Consecutive cohort study, Review Board No. EK-2-2014/0016.

Magnetized Dusty Black Holes and Wormholes

We consider the generalized Tolman solution of general relativity, describing the evolution of a spherical dust cloud in the presence of an external electric or magnetic field. The solution contains three arbitrary functions f(R), F(R) and τ0(R), where R is a radial coordinate in the comoving reference frame. The solution splits into three branches corresponding to hyperbolic (f>0), parabolic (f=0) and elliptic (f<0) types of motion. In such models, we study the possible existence of wormhole throats defined as spheres of minimum radius at a fixed time instant, and prove the existence of throats in the elliptic branch under certain conditions imposed on the arbitrary functions. It is further shown that the normal to a throat is a timelike vector (except for the instant of maximum expansion, when this vector is null), hence a throat is in general located in a T-region of space-time. Thus, if such a dust cloud is placed between two empty (Reissner–Nordström or Schwarzschild) space-time regions, the whole configuration is a black hole rather than a wormhole. However, dust clouds with throats can be inscribed into closed isotropic cosmological models filled with dust to form wormholes which exist for a finite period of time and experience expansion and contraction together with the corresponding cosmology. Explicit examples and numerical estimates are presented. The possible traversability of wormhole-like evolving dust layers is established by a numerical study of radial null geodesics.

METHODS OF PROJECT-VECTOR MANAGEMENT OF EDUCATIONAL ENVIRONMENTS

Based on the developed mathematical model of the project-vector space, the methods of determining the endpoints of the objects of the project-vector space (PVS) and the calculation of the trajectory of the movement to these points are proposed. It is shown that the problem of developing these methods is related to the definition of such projects (project integration), which will correspond to the maximum expansion of “Universal Projects” educational environment. Calculation of the trajectory of the movement in the project-vector space ensures the achievement of the objectives of the project with minimal time and financial resources. It is proposed to use the Monte Carlo method to calculate the options for the trajectory of PVS subjects. This distribution of probabilities when choosing the displacement of objects and subjects of PVS corresponds to the priority of subjects and the impact of objects on the displacement of these subjects. For the assessment of the magnitude of the impact on the movement of PVS subjects it was developed the structure of the expert table and the model of the calculation of the average expert assessment of such an impact. Implementation of the given methods will allow to dynamically evaluate the most important goals for all interested parties of the project, as well as to develop ways to achieve them in real terms. In this case, the real conditions of the projects are described in the system of impact on the movement of objects and subjects of PVS in the expanding “Universal Projects”.

Universe: the dynamics of the minimum and maximum expansion states

Two hypotheses stand out in describing the evolution of the Universe. The predominant one predicts that the current expansion began at a certain instant and will not preserve any variation of energy that performs work; apparent flat Universe (Ω = 1) is advocated by relativistic calculations and observational data, with an end or thermal death at its maximum expansion (3D Space). The other hypothesis considers that the Universe is cyclical (always alternating phases of expansion and contraction). This proposal aims to demonstrate that both hypotheses can be correct by not being distinct, but complementary. Supported by the immutability of physical laws, analyses of concepts such as space, mass, energy, gravity, spin, and entropy define an exclusive presence of 1D Space in the minimum and maximum expansion states of the Universe. With our 3D Space Universe created and existing between these extreme states, every dynamic is outlined and completes the usual relativity. The concept of complete rest energy (1D Space) was able to be applied, demonstrating that the complete evolution of the Universe is spatially dynamic in a perpetual time dimension, always recreating our Universe.

Universe: the dynamics of the minimum and maximum expansion states

Two hypotheses stand out in describing the evolution of the Universe. The predominant one predicts that the current expansion began at a certain instant and will not preserve any variation of energy that performs work; apparent flat Universe (Ω = 1) is advocated by relativistic calculations and observational data, with an end or thermal death at its maximum expansion (3D Space). The other hypothesis considers that the Universe is cyclical (always alternating phases of expansion and contraction). This proposal aims to demonstrate that both hypotheses can be correct by not being distinct, but complementary. Supported by the immutability of physical laws, analyses of concepts such as space, mass, energy, gravity, spin, and entropy define an exclusive presence of 1D Space in the minimum and maximum expansion states of the Universe. With our 3D Space Universe created and existing between these extreme states, every dynamic is outlined and completes the usual relativity. The concept of complete rest energy (1D Space) was able to be applied, demonstrating that the complete evolution of the Universe is spatially dynamic in a perpetual time dimension, always recreating our Universe.