Maximum Allowable Depth Research Articles

Investigating effects of mining on sedimentary properties of Lisar River (Guilan Province, Iran) using HEC_RAS model

ABSTRACT Increasing land development projects lead to demand for riverine mining, followed by erosion and deposition. The aim of the research was to assess the sedimentary impacts of mining activities on the Lisar River. The research material comprised environmental, hydraulic, and sedimentary information, mining history, and dimensions. Detailed topographic and TIN maps, and 55 cross-sections of the Lisar River mining, were prepared. This study simulates flow patterns in a quasi-unsteady condition and sediment transport capacity using the HEC-RAS model. The maximum change along the longitudinal profile of the river mining is 3 m. The spatial map of the mining in different river sections was determined based on the maximum allowable depth of mining. The present research recommends the Yang function use in simulations of the rivers with sandy-gravel texture accompanied with or without riverine mining and steep slope. Results indicate the current mining volume is up to three times the allowed capacity for the extraction from the Lisar River. The present research concluded that the management plan for spatial mining and measures for monitoring based on the spatial distribution of depositional and erosional sites is necessary for this and other such areas to conserve natural resources.

Hybrid Manufacturing of Stiffening Grooves in Additive Deposited Thin Parts

This paper is focused on the hybridization of additive manufacturing with single-point incremental forming to produce stiffening grooves in thin metal parts. An analytical model built upon in-plane stretching of a membrane is provided to determine the tool force as a function of the required groove depth and to estimate the maximum allowable groove depth that can be formed without tearing. The results for additively deposited stainless-steel sheets show that the proposed analytical model can replicate incremental plastic deformation of the stiffening grooves in good agreement with experimental observations and measurements. Anisotropy and lower formability caused by the dendritic-based microstructure of the additively deposited stainless-steel sheets justifies the reason why the maximum allowable depth of the stiffening grooves is approximately 27% smaller than that obtained for the wrought commercial sheets of the same material that are used for comparison purposes.

Gas Lift Performance of Some Horizontal Wells in Ahdeb Oil Field

Ahdeb is one of the Iraqi oil fields, its crude characterized by medium API (22.5-28.9) and highly reservoir pressure depletion from Khasib formation due to lack of water drive. This makes it difficult to produce economic oil rates. Therefore, many water injection wells were drilled by the operators to maintain the reservoir pressure during production. In addition to that, electrical submersible pumps (ESP) were used in some productive wells. This study suggests exploitation of gas associated with oil production to be recycled to lift oil as a substitute for the ESP .The work in this study includes using PIPSIM software to build a model of four studied productive wells (AD1-11-2H, AD2-15-2H, AD4-13-3H, A4-19-1H) after choosing the suited correlation for each well. According to the statistical results, Mukherjee & Brill correlation is the best option for all wells.
 The use of PIPESIM software include determining artificial lift performance to determine the optimum amount of gas injected, optimum injection pressure as well as the optimum injection depth and knowing the impact of these factors on production, as well as the determination of the optimal injection conditions when water cut changes. According to the current circumstances of the wells, the depth optimized for injection is the maximum allowable depth of injection which is deeper than the packer by 100 ft and the amount of injection gas is (1.5, 1, 1, and 1) MMscf/day for wells (AD2-11-2H, AD2-15-2H, AD4-13-3H, and AD4-19-2H) sequentially and injection pressure (2050, 2050, 2050, and 2000) psi for wells (AD2-11-2H, AD2-15-2H, AD4-13-3H, and AD4-19-2H) sequentially.

Testing thermodynamics method for salt intrusion during infrequent astronomical event

Knowledge of the processes governing salt intrusion in estuaries is important since it influences the eco-environment of estuaries as well as its water resource potential in many ways. The aim of this paper is to test the effectiveness of the new 1-D thermodynamic salt intrusion equation proposed by Zhang and Savenije (i.e., is an extreme power theory for the mixing of saline sea water and fresh river water in estuaries); and existing salt intrusion model (i.e., Van der Burgh method) at two previously unsurveyed estuaries in India and Morocco. To successfully perform the analysis using the 1-D models, real time data is required. Field measurements during infrequent astronomical event were recorded along the estuaries (31/01/2018 for Ashtamudi estuary (India); and during 31/01/2018 for Bouregreg estuary (Morocco)). Shape (geometry) and salinity analyses were performed on each of the estuaries. The results obtained show good agreement between the simulated and observed salinity distribution in the estuaries with high R 2 values. Finally, by utilizing the new predictive equation, we can estimate the minimum amount of river discharge needed, and the maximum allowable depth for dredging, to prevent saline water intruding further into the areas studied. Thus, the simple and effective approach presented in this study can describe the current state of salt intrusion in India and Morocco estuaries, and be used for future development.

The research of the stress-strain state with local thinning in pipelines and determination of allowable values of concentration stress and strain

Relevance. The nuclear power plant contains a large number of equipment and pipelines subject to flow acceleration corrosion. As a result of a combination of various parameters - sizes (diameters, wall thickness), operational parameters (internal pressure, temperature), steels and elements types - the number of design cases is tens of thousands, without counting the possible forms of thinning. The process of maintenance and repair at the stations are doing an assessment of the accordance of actual and allowable values of wall thicknesses. The ensuring safe operations of equipment and pipelines have been introduced correction functions for regulatory functions, taking into account the forms of thinning, to determine the permissible thinning. The aim of the work. The task is to determine the influence of the forms and types of thinning on the stress-strain state and to determine the most critical thinning for straight sections of pipelines subject to flow acceleration corrosion taking into account emergency conditions. Methods. The allowable values of stress concentration factors (deformations) of pipelines subject without flow acceleration corrosion was determined taking into account allowable values, the requirements of the federal norms and rules for emergency operating conditions. For researches of the stress concentration coefficients were used the finite element method and analytical methods for various shapes, sizes and depths of thinning. Results. A method has been developed, that allows getting the maximum allowable values of stress concentration factors (deformations) for emergency operation, which afford to determine the maximum allowable depth of thinning in emergency conditions - an above criterion. The researches have been carried out definition of the stress concentration factors for local thinning with various types of these thinning. The functions of concentration coefficients depending on the geometric parameters of local thinning wall thickness were determined for a straight section of the pipeline. As a result of the research, the dependences of the sizes of thinning on the concentration coefficients for straight pipelines were created and a master-curve was obtained. The researches were carried out take into account the load from internal pressure and bending moment.

РЕЗУЛЬТАТЫ ИССЛЕДОВАНИЙ РАЗВИТИЯ ТРЕЩИН В ГОЛОВКАХ БЛОКОВ ЦИЛИНДРОВ ДВИГАТЕЛЯ ЯМЗ-238НБ

The purpose of the study is to identify the maximum depth of the crack does not affect the normal working movement of the gates. To determine the nature and dynamics of growth heattransaction cracking of the cylinder head and waveness the maximum value of the crack depth and without disrupting the normal operation of the engine. Head material is grey cast iron SCH25 implies the presence of graphite inclusions, lamellar form. Also, this material structure is not optimal to improve the heat transfer, which increases thermal stresses. On the surface and the thickness of the firing of the bottom and leads to the appearance of such incidental defects, such as heatmobile cracks inside cylinder jumpers. Therefore, this defect limits the resource base. The study termodecreased depth of cracks was carried out according to the above method. The results of the studies the magnitude of this defect for the engine YAMZ-238НБ showed that the greatest dynamics of development of this defect is observed in inside cylinder the jumper between the injector hole and socket of the inlet valve. This area is characterized by the greatest temperature changes and mechanical stresses along the thickness and width of the site. It is observed during the period of achievements of 2000-3000 hours. Justified and proposed maximum allowable depth of cracks termodecreased for fire bottom of the cylinder heads in which no emergency is occurring defects of this part. This value should be considered the 6.5 mm because remaining intact the thickness of this zone provides the resource of this part until the next major overhaul. Depth control termodecreased of cracks will allow you to save some spare parts for major repairs of the engine to optimize the reuse of cylinder heads of engines.

Analysis of the depth of field in hexagonal array integral imaging systems based on modulation transfer function and Strehl ratio.

Integral imaging is a technique for displaying three-dimensional images using microlens arrays. In this paper, a method for calculating root mean squared wavefront error and modulation transfer function (MTF) of a defocused integral imaging capture system with hexagonal aperture microlens arrays is introduced. Also, maximum allowable depth of field with Century MTF analyzing and Strehl criterion are obtained.

External Reference Nasal Pin for Orthognathic Maxillary Positioning: What Is the Proper Method of Placement?

Intracranial perforation with an external reference nasal pin is a possible complication during maxillary orthognathic surgery. This study attempts to quantify the maximum allowable depth of pin penetration from the soft tissue nasion (STN) and hard tissue nasion (HTN) to the anterior cranial fossa (ACF) and to evaluate the depth and direction of the nasal pin track using postsurgical cone-beam computed tomography (CBCT). Two groups of patients were evaluated. A retrospective cross-sectional chart review evaluated the distance from the STN and HTN to the ACF from random patients on CBCT scans. In addition, a different group of postsurgical orthognathic cases treated between March 2013 and August 2015 were analyzed for the depth and direction of the nasal pin track toward the next anatomic cavity, which included the ACF, frontal sinus, or nasal cavity. We identified 103 random patients, aged 14 to 90 years. The mean distance from the STN to the ACF was 21.85 mm (range, 14.06 to 29.12 mm), and the mean distance from the HTN to the ACF was 14.16 mm (range, 7.35 to 20.53 mm). Forty postsurgical CBCT scans showed an overall nasal pin track depth of 12.91 mm (range, 8.53 to 22.60 mm), with the direction of the pin track toward the nasal cavity in most cases. The depth of penetration of an external reference nasal pin should be limited to a maximum of 10 to 12 mm from the STN. Initial skin penetration should begin immediately caudal to the STN, and the pin should be directed in a caudal direction to avoid inadvertent entrance into the ACF, as well as to facilitate a relatively safe penetration into the nasal cavity, if the maximum depth is excessive.

Low Complexity Adaptive View Synthesis Optimization in HEVC Based 3D Video Coding

In this correspondence, we explore a low-complexity adaptive view synthesis optimization (VSO) scheme in the upcoming high-efficiency video coding (HEVC)-based 3-D video coding standard. We first devise a novel zero-synthesized view difference (ZSVD) model which jointly accounts for the distortion of the synthesized view induced by the compound impact of depth-disparity mapping, texture adaptation, and occlusion in the view synthesis process. This model can efficiently estimate the maximum allowable depth distortion in synthesizing a virtual view without introducing any geometry distortion. Then, an adaptive ZSVD-aware VSO scheme is proposed by incorporating the ZSVD model into the rate-distortion optimization process, which is developed by pruning the conventional view synthesis algorithm. Extensive experimental results confirm that the proposed model is capable of accurately predicting the zero distortion of the synthesized view and exhibit that the proposed ZSVD-aware VSO scheme can remarkably reduce the coding computational complexity with negligible performance loss.

Optimal design of rectangular RC sections for ultimate bending strength

A minimum cost problem for ultimate strength in bending of rectangular reinforced concrete sections is investigated. The design variables are section depth and steel reinforcement areas. State equations are those of equilibrium with compression depth as state variable. The Kuhn-Tucker optimality conditions are solved analytically and formulas for nondimensional design and state variables are obtained in four cases: Two singly-reinforced solutions with either maximum allowable depth or smaller; Two doubly-reinforced with maximum allowable depth and either maximum compression depth or smaller. Each of the solutions is optimal in a region of the plane `nondimensional bending moment'---`cost-effectiveness ratio of concrete to steel'. The formulas are for an arbitrary concrete constitutive law with tension cut-off and are specialized for the parabola-rectangle law of Eurocode 2.

Assessment and prediction of daylight performance in high‐rise office buildings

AbstractEffective use of daylighting is an essential component to achieve a sustainable building design. In a tall building, the amount of useable space with a potential for the use of daylight is the space between the exterior wall and the core. This is commonly referred to as the ‘lease span’. Class A office buildings in the USA have typically utilized lease spans of around 45 ft (13·7 m), primarily due to efficiency of space usage. In Europe, however, lease spans in high‐rise office buildings have typically been shortened due to concerns of natural light penetrations and views. For instance, in Germany, the amount of leasable space per floor is less than in the USA. The maximum allowable depth of space in Germany is typically about 18 ft (5·5 m), whereas in the USA, as much as 50 ft (15 m) is no rarity. The lease span also has an impact on other items, such as the aspect ratio, floor‐to‐floor height, total height and total floor area. In this study, to assess and predict daylight performance, two different requirements were analysed: daylight factor (DF) and the daylight requirement of Leadership in Energy and Environmental Design (LEED) 2.2 green‐building rating system. The recommended average DF (DFave) ranges from 2 to 5% and LEED 2.2 requires that a minimum daylight illumination of 25 footcandles be achieved in at least 75% of all regularly occupied areas. This study conducted a series of computer simulations using RADIANCE to first show the effects of each of the fenestration parameters and then to provide an optimum effective aperture to meet the two daylight requirements in four lease span types ranging from 20 to 50 ft. As a final step, regression models and simple evaluation tools were developed to correlate the DF, daylight requirement in LEED 2.2 and the various fenestration parameters, such as window area, visible transmittance and lease span in four different cities (London, Chicago, Dubai and Bangkok). This paper provides a simplified method for evaluating indoor daylight performance to meet the two daylight requirements. This can be used as a pre‐design tool, not only to achieve more credits in LEED 2.2 green‐building rating systems, but also to evaluate based on DFave to ensure that the building meets the recommended level. Copyright © 2008 John Wiley & Sons, Ltd.

Simulation of durability of cylinder liners of an internal combustion engine under vibration cavitation

A method is presented for the experimental and calculated estimation of the reliability of internal combustion engine liners exposed to the cavitational-erosive effect of liquid coolant. Combating corrosion of liners of high-and medium-speed engines has remains important because the life of liners with regard to cavitation erosion is approximately four times shorter than that with regard to the cylinder face wear and parts are rejected on the basis of the maximum allowable depth of erosion pits on the water-cooled surface. The procedure of estimating the durability of liners assumes the successive determination of their amplitude-frequency characteristics, the period of damage accumulation, and the highest erosion rate and then an estimation of the liner durability using the kinetic dependence of wear at the moment when the pit depth reaches 75% of the liner wall thickness. By the example of a 2Ch 8.5/11 engine, a satisfactory correlation is demonstrated between experimental data and the results of engine service.

Depth Limitations on Bulk Piling of Sweet Potatoes

ABSTRACT LABORATORY tests were conducted to estimate the maximum allowable depth of piling sweet potatoes in large, continuous volume piles for curing and long-term storage. Based on published and measured physical properties, the maximum allowable depth was estimated to be 5.000 m. Comparison of experimental weight loss data obtained in simulated deep piling tests with accepted norms resulted in an estimate of 5.400 m.

主軸速度変動切削方式による安定限界の向上

By a programed variation of the spindle speed of machine tools, it is possible to control the onset of the regenerative-type self-excited chatter. In this paper, the effect of the wave form of spindle speed variation and the practical improvement of the metal removal rate in this method are theoretically analyzed, and the results are verified by some turning experiments. The results obtained are as follows. (1) Among various waves such as rectangular wave, sinusoidal wave, triangular wave and multi-stepped wave, the triangular wave is the most effective as the mode of spindle speed variation. (2) By means of complex method, it is possible to find more effective wave form of spindle speed variation theoretically. (3) If the dynamic characteristics of the cutting process and the machine tool structure are known, it is possible to predict the maximum allowable depth of cut under varying spindle speed.