PENENTUAN POLA OPERASI PINTU PELIMPAH DALAM RANGKA PENGENDALIAN BANJIR BENDUNGAN DELINGAN, JAWA TENGAH

A spillway is one of many important components of a dam, which is operated to prevent the dam from overtopping. Spillway with gate structures requires to have a good operation pattern by considering a minimum critical height and outflow discharge to prevent any flooding events in the downstream part of the spillway channel. The case study in this research is the Delingan Dam which has two ogee spillways, four main sluice gates and four additional sluice gates. Located in Karanganyar District, West Java, Delingan Dam is considered as a vast infrastructure which is potentially threatening if the spillway’s operation is not optimal. This study aims to analyze the spillway gate operations’ pattern of Delingan Dam in order to control the flooding event. The methodology used in this study is flood routing by utilizing several scenarios in order to obtain the optimal simulation results. Five scenarios that were simulated on the designated flood discharge have various combinations on the number of gates and their opening, as well as the time in which the operation started. The results show that the operation only using ogee spillway still meets the criteria for minimum critical height and maximum allowable discharge for return period of 25, 50, and 100 year.As the discharge with 1000 year return period, half of PMF, and PMF,the recommended operation is, foremost, to occupy the main gate in which results in the peak outflow discharge of 23.65 m3/s, 62.4 m3/s, and 140.9 m3/s, with the minimum critical height of 1.45 m, 1.41 m, and 1.35 m, respectively. However, this operation is not adequate for the half of PMF, and the PMF discharge, since the capacity in the spillway channel is estimated about 24.7 m3/s.Keywords: spillway, flood control, spillway gate operation, the delingan dam

EFFECT OF WATERTIGHT SUBDIVISION ON DAMAGE STABILITY OF RO-RO FERRIES

Effect of various subdivision arrangements of ro-ro vessels on damage stability is discussed. The arrangements included single and double sides both below and above the car deck, with and without a double buoyant car deck, and with or with- out a watertight tween deck below the car deck. This gave as many as 16 various arrangements for each compartment length. The double sides both above and below the car deck are of the same width b = 0.1B. The double bottom, when not flooded, worsens damage stability. The car deck and tween decks should be ‘openwork’, to be transparent for water and air. Oth- erwise, the ship can capsize at the very initial stages of flooding. Double sides and a double car deck together improve con- siderably damage stability, both in terms of maximum arm and range. A new characteristic was introduced, termed the critical deck height. Flooding a deck above the critical height leads to a rapid capsizing of the ship.

Partial Eruption, Confinement, and Twist Buildup and Release of a Double-decker Filament

We investigate the failed partial eruption of a filament system in NOAA AR 12104 on 2014 July 5, using multiwavelength EUV, magnetogram, and Hα observations, as well as magnetic field modeling. The filament system consists of two almost co-spatial segments with different end points, both resembling a C shape. Following an ejection and a precursor flare related to flux cancellation, only the upper segment rises and then displays a prominent twisted structure, while rolling over toward its footpoints. The lower segment remains undisturbed, indicating that the system possesses a double-decker structure. The erupted segment ends up with a reverse-C shape, with material draining toward its footpoints, while losing its twist. Using the flux rope insertion method, we construct a model of the source region that qualitatively reproduces key elements of the observed evolution. At the eruption onset, the model consists of a flux rope atop a flux bundle with negligible twist, which is consistent with the observational interpretation that the filament possesses a double-decker structure. The flux rope reaches the critical height of the torus instability during its initial relaxation, while the lower flux bundle remains in stable equilibrium. The eruption terminates when the flux rope reaches a dome-shaped quasi-separatrix layer that is reminiscent of a magnetic fan surface, although no magnetic null is found. The flux rope is destroyed by reconnection with the confining overlying flux above the dome, transferring its twist in the process.

Mathematical Modelling to Determine the Greatest Height of Trees

This study aimed to analyse the critical height of a column whose weight varies vertically in order to obtain a simple scaling law for a tree where the weight distribution considered. We modelled trees as cantilevers that were fixed to the ground and formulated a self-buckling problem for various weight distributions. A formula for calculating the critical height was derived in a simple form that did not include special functions. We obtained a theoretical clarification of the effect of the weight distribution of heavy columns on the buckling behaviour. A widely applicable scaling law for trees was obtained. We found that an actual tree manages to distribute the weight of its trunk and branches along its vertical extent in a manner that adequately secures its critical height. The method and findings of this study are applicable to a wide range of fields, such as the simplification of complicated buckling problems and the study of tree shape quantification.

Minimally critical regular endomorphisms of

We study the dynamics of the map $f:\mathbb {A}^N\to \mathbb {A}^N$ defined by $$ \begin{align*} f(\mathbf{X})=A\mathbf{X}^d+\mathbf{b}, \end{align*} $$ for $A\in \operatorname {SL}_N$ , $\mathbf {b}\in \mathbb {A}^N$ , and $d\geq 2$ , a class which specializes to the unicritical polynomials when $N=1$ . In the case $k=\mathbb {C}$ we obtain lower bounds on the sum of Lyapunov exponents of f, and a statement which generalizes the compactness of the Mandelbrot set. Over $\overline {\mathbb {Q}}$ we obtain estimates on the critical height of f, and over algebraically closed fields we obtain some rigidity results for post-critically finite morphisms of this form.

Prospective designs of self-extinguishing devices for spills of burning engine fuels

Проведены теоретические и экспериментальные исследования процессов горения и прекращения горения моторных топлив в трубчатых вертикальных каналах без применения средств пожаротушения. Разработаны технические решения, обеспечивающие локализацию проливов горящих жидкостей и эффективное прекращение горения проливов бензина, летнего, зимнего и арктического дизельных топлив. По результатам проведенных исследований разработаны перспективные конструкции устройств, обеспечивающие самотушение моторных топлив за время не более 300 с. В данных конструкциях реализуется принцип подавления естественной конвекции с помощью ряда конструктивных приемов, которые нарушают взаимосвязь пламени с испаряющейся жидкостью и воздушной средой, создавая тем самым условия прекращения горения. There were found technical solutions for localization of spills of burning liquids and effective flame suppression, called self-extinguishing devices for spills of flammable liquids (USP) on the basis of researches conducted by FGBU VNIIPO EMERCOM of Russia (VNIIPO). Currently there are developed several types of USP differ from each other in design solutions due to the conditions of their practical application. The efficiency of devices is confirmed by numerous experiments on self-extinguishing of burning spills of transformer and turbine oils, conducted by VNIIPO and LLC “SKB” Tensor” in the interests of electric power companies. A number of copyright certificates and patents for inventions were obtained. The principle of suppressing natural convection is implemented in the configuration of USP by a number of design techniques that violate the connection of flame with evaporating liquid thereby creating burnout conditions. This paper presents investigation results on development of self-extinguishing devices for spills of burning motor fuels. The conducted theoretical studies of possibility of extinguishing motor fuels in the channels of USP devices allowed us to determine the critical height of the channels at which self-extinguishing of motor fuels occurs. The results of theoretical studies were confirmed experimentally. The experiments were conducted in two stages. There were tested 15 experimental samples of grids of modular USP assemblies with a ratio of lengths and diameters of vertical channels of 3.8 at the first stage of experiments. At the second stage there were tested 4 mock-up samples of USP for motor fuels manufactured by LLC “SKB “Tensor” with a ratio of lengths and diameters of vertical channels from 3.8 to 6 with grid elements and with flat and volumetric hydraulic locks. There were identified the most promising USP designs that provide self-extinguishing of engine fuel spills with the necessary parameters.

REAL OPTION AND VERTICAL MIXED-USE DEVELOPMENT

Vertical mixed-use development is a favourite choice in urban development in high-density Asian cities to increase the land use efficiency. The flexibility of construction timing and the restrictions by lease contracts in vertical mixeduse projects are usually different from horizontal ones and single-use properties. To improve the valuation for vertical mixed-use projects, this study re-examines the real option pricing model. Simultaneous development for different uses and a finite maximum waiting period are the major characteristics of these projects. An approach is introduced to determine whether to develop a mixed-use project vertically or horizontally on the basis of a statistics called the critical height premium. The vertical mixed-use project pricing model can be further verified by containing a height premium if market price information is derived from non-vertical mixed-use properties. This study suggests a more comprehensive real option approach to quantify the advantages and disadvantages of operating vertical mixed-use developments.

Critical Height of Unfilled Zone in Underlying Gob Piles

To address problems associated with mining above gob piles in the Chinese midwest mining area, a mechanic model for a coal pillar was established based on the displacement variation method. Additionally, the effect of critical unfilled zone height in the underlying gob (UZHUG) on the coal pillar was investigated through a 3DEC numerical simulation; fieldwork was conducted with a borehole televiewer to measure the UZHUG in the Yuanbaowan Coal Mine. The results indicated that the shear stress value and distribution layout in the coal pillar were affected by the UZHUG. The larger the UZHUG, the greater the shear stress and the wider the distribution scope, moving from two sides to the middle zone. Moreover, the larger the UZHUG, the smaller the maximum bearing capacity of the coal pillar, and subsequently, the greater the horizontal deformation of the coal pillar and roof convergence. The critical UZHUG is 2 m considering coal pillar deformation and stress transfer characteristics. Field measurements have confirmed that the UZHUG of 2 m ensured safe mining in the No. 6 coal seam. However, a second round of filling is needed when achieving a UZHUG of 4.4 m. This study serves as a reference for safe mining above gob piles.

The effect of static deformation on the lift loss phenomenon of an ABS downforce producing wing in ground effect

The proximity of a downforce producing wing to the ground has a significant effect on the generation of aerodynamic loads and flow structures. However, a rigid body assumption for the wing may lead to inaccuracies in the estimation of these loads. Static loosely-coupled Fluid-Structure Interaction (FSI) simulations were performed at Reynolds numbers of 4.64·105 and 6.96·105 and ground clearances ranging from 0.053 c to 0.223 c to investigate the effect of deformation in an ABS wing. Results of these simulations demonstrated that wing deflection increased the height at which lift loss occurred, as the reduced wing tip ground clearance led to an earlier main wing vortex breakdown and greater boundary layer separation. The increase in Reynolds number for a constant chord length induced larger variations in critical height: the critical height increased by 0.011 c at Re = 4.64·105 and by 0.021 c at Re = 6.96·105. The larger variation in critical height at the high Reynolds number cases was due to the increase in the magnitude of the aerodynamic loads, and larger deflections.

The efficiency assessment of an automatic sprinkler system

Introduction. Сases of ineffective activation of automatic sprinkler fire-fighting systems (AFFS), designed pursuant to current standards, have made it necessary to address the following three issues: a) identification of reasons for ineffective activation; b) examination of AFFS systems to ensure their successful activation in case of fire; c) making a list of recommendations for AFFS designers. These issues can be resolved with reference to Appendix B to new SP (Construction Regulations) 485.13130.2020.Maximal critical height of sprinkler placement. Models of fire development were used to design the roof height limit and the AFFS bulb heating time. If the ceiling height exceeds the limit value, sprinklers cannot be activated in a timely manner. This leads to delays in the AFFS activation, and, as a result, the fire area exceeds the one safeguarded by the sprinkler.Acceptable sprinkler height. The analysis of fire scenarios and bulb heating models allows to more accurately project the feasibility of timely AFFS activation. This, in turn, allows to solve the three above listed problems.Using a differential heat detector to activate sprinklers. If it is established that the use of the AFFS, activating sprinklers by means of thermal destruction of a bulb, is ineffective in a given room, the feasibility of forced AFFS activation using a differential heat detector responding to the temperature rise in a room may be considered. The ratios, thus obtained, are applied to identify the acceptable height of premises protected by the AFFS equipped with such detectors. Problem solutions, including the identification of the reason for the ineffective operation of the AFFS, examination of the AFFS in operation, and provision of recommendations to designers, are demonstrated using the exhibition hall as an example.Conclusions. The above-mentioned problems are resolvable with the help of Appendix B to new Construction Regulations 485.13130.2020 and the above models.