Shed Roof Research Articles

Numerical Simulation of a Shed-Tunnel Structure’s Dynamic Response to Repeated Rockfall Impacts Using the Finite Element–Smoothed Particle Hydrodynamics Method

In practical engineering, a shed-tunnel structure often encounters repeated impacts from rockfall during its whole service life; therefore, this research focuses on exploring the dynamic response characteristics of shed-tunnel structures under repeated impacts from rockfall with a numerical method. First of all, based on a model test of a shed tunnel under rockfall impacts as a reference, an FEM (finite element method)-SPH (Smoothed Particle Hydrodynamics) coupled numerical calculation model is established based on the ANSYS/LS-DYNA finite element code. Numerical simulation of the dynamic response of the shed-tunnel structure under rockfall impacts is realized, and the rationality of the model is verified. Then, with this model and the full restart technology of the LS-DYNA code, the effects of four factors, e.g., rockfall mass, rockfall impact velocity, rockfall impact angle and rockfall shape, on the impact force and impact depth of the buffer layer, the maximum plastic strain and axial force of the rebar, the shed roof’s vertical displacement and plastic strain of the shed tunnel are studied. The results show that the impact force, impact depth, roof displacement and plastic strain of the shed tunnel are positively correlated with the rockfall mass, velocity and angle under multiple rockfall impacts. The impact force, roof displacement and plastic strain of the shed-tunnel structure generated by the impact of rockfall consisting of cuboids are all greater than those under spherical rockfall, and the impact depth generated by the impact of spherical rockfall is greater than that of rockfall consisting of cuboids. For rockfall consisting of cuboids, the impact depth, roof displacement and plastic strain are negatively correlated with the contact area. Under repeated rockfall impacts, the peak impact force usually increases first and then tends to be stable.

Wind tunnel experiment on cross-ventilation of generic isolated building with various roof shapes: Impact of roof pitch and eaves

This study examined the effects of roof shape, specifically roof pitch and eaves, on cross-ventilation performance through wind tunnel experiments that measure static pressure on walls and the detailed wind velocity distribution for isolated building models with basic roof geometries. A flat roof, a gable roof, and two types of shed roof with different orientations were compared. The buildings with a flat or shallow roof pitch (15°) showed no significant change in the pressure difference between windward and leeward facades. However, a steeper roof pitch (30°) caused a significant increase in pressure difference, especially for the shed roof that ascends in the wind direction (shed-A roof). This was caused by larger projected building areas creating stronger recirculation zones behind the building, leading to lower pressure on the leeward facade. The shed-A roof with a pitch of 30° had the best ventilation performance among the tested cases. Eaves generally reduced pressure differences, except for the shed-A roof. The effect of eaves was weaker than reported in previous studies. The experimental results obtained in this study can serve as a validation database for a more detailed study of this problem using computational fluid dynamics.

Efficiency Assessment on Roof Geometry and Trombe Wall Shape for Improving Buildings’ Heating Performance

It is crucial to consider structural design issues in Trombe wall (T-wall) buildings to promote more suitable indoor climates and thermal comfort standards. Therefore, the present study examined the impact of two different T-wall designs and six different roof types on the energy and operational efficiency of a building located in a low-temperature and high-humidity winter climate. Ansys-CFX 15.0 software was employed to simulate the thermal and fluid dynamics behavior of the T-wall system, and flow, thermal comfort, energy, and exergy analyses were conducted. Three-dimensional simulation results and the pertinent literature data showed a good level of agreement, and the accuracy of the model was ensured. Outcomes revealed an average air velocity variation of 0.186 m/s and maximum average indoor air temperature variation of 3.3 °C between the six roof geometries. The highest air speed (0.988 m/s) was recorded for the gambrel roof while the lowest one (0.802 m/s) was recorded for the typical flat roof. The shed roof right with a rounded T-wall was more comfortable for standing and sitting activity than the others for the two T-wall shapes, and, at Y = 0.6 m and Y = 1.1 m, the average predicted percentages of dissatisfied (PPD) values were 31 and 28%, respectively. Furthermore, it was determined in the study that solar radiation intensity and T-wall and roof geometries had a significant effect on energy and exergy efficiency, and high energy and exergy efficiencies were achieved at higher solar intensity values. The best energy and exergy efficiencies were obtained for the butterfly and shed roof configurations. This study can serve as a reference for the thermal environment design of buildings with T-walls.

Experimental study on multiple impact resistance of geogrid reinforced cushion

Rock-sheds are often used at mountain roads and tunnel entrances for preventing rockfall disasters. Placing geogrids in sand cushion can improve the resistance to rockfall impacts. However, the mechanism of geogrid reinforced sand cushion under multi-impacts remains unclear. This study conducted four model tests to investigate the mechanical response of geogrid-sand cushions with different reinforcement positions under multiple impacts. The results showed that geogrids effectively reduced the impact penetration depth and improved its buffering capacity. When the geogrid was placed at 2/3 the height of the cushion, with increase in the number of impacts, the growth rate of the maximum impact force and peak earth pressure, and the reduction rate of the penetration depth and impact stress factor were the smallest. Moreover, the vibration of the shed roof slab was mitigated. This is because this working condition effectively converted the impact stress into horizontal tensile stress of the geogrid, which is beneficial for evening the distribution of the stress on the shed roof slab. Thus, this study provides a reference for the optimization and design of rock-sheds.

Numerical Design of the Roof Structure of a Vehicle Charging Carport Based on the Dragonfly Wing Grid Pattern

The realization of the global “Double carbon” target is closely related to the energy-saving travel of human beings. Along with the increase in the number of new energy vehicles around the world, the number of new energy vehicle charging post carports has also increased. However, the collapse of the carport of the new energy vehicle charging post often occurs. The search for ways to optimize the carport structure construction and build a lighter and more stable charging post carport structure has become one of the hot spots in the new energy vehicle industry. Dragonfly wings have a comprehensive evolution in structure, form and function, and their stiffness, stability and resistance to deformation may be a potential solution to optimize the structure of the shed roof. Inspired by this, the study designs two new energy vehicle charging pile canopies based on the dragonfly wing mesh structure to enhance the loading capacity and structural stability of the canopies. The study firstly concludes that the dragonfly wing mesh can enhance the stiffness through experimental analysis, and simulates and models the structure based on the quadrilateral mesh wrinkling and hexagonal mesh arching in its mesh morphology, combined with the national design standard of the charging pile canopy. Studies on the numerical design experiment of the new energy vehicle charging station canopy model based on finite element software under different natural loads, the deflection of shed under the action of self-weight and the deflection, tensile stress and compressive stress under external load are analyzed, and the results show that: (1) The grid structure of the dragonfly wing bionic charging pile shed can optimize the stiffness of the car charging pile shed. (2) According to the wing structure, the test results of the shed roof structure under different working conditions are better than the national standard. (3) Compared with the vertical load, the transverse load of the arched membrane structure, which is represented by the charging pile shed of the new energy vehicle, is larger. (4) According to the stress point of the shed, the structure constraint of the shed can effectively reduce the pressure on the and share part of the load, which can enhance the stability of the shed. (5) In comparison with the displacement of common carport types, the bionic carport shows superior stability and durability. The new bionic carport structure proposed by the research, with stronger pressure bearing, smaller force deformation and lighter weight, is a kind of membrane structure for stable new energy vehicle charging pile carports, which will help further the optimization and promotion of the new energy vehicle industry.

The influence of attics space geometrical shape on ignition and flashover stages in residential building fires in dense settlements

As an artificial physical place, residential building is formed by various functional spaces, such as residential space and the space between the ceiling space and the roof, i.e. the attics. The phenomenon of fires in residential buildings in densely populated areas is suspected of having occurred in the attics. Hitherto, research on the fire space model concerning the stages of ignition and flashover usually employs the Steckler's compartment model in the form of a cube/box. On the contrary, the fire model with a triangular roof shape is still rarely studied. The purpose of this study was to analyse the influence of the geometric shape of the attics on the ignition and flashover stages in residential fires located in densely populated settlements. This study employs an experimental method by conducting scaled experiments of the geometric model of the ceiling space in the form of a triangular gable roof and shed roof, focusing on the ignition and flashover stages. The results showed that the ignition stage in the gable roof and shed roof models occurred in the 3rd and 4th minutes with a temperature ranging from 270 ⁰C- 476 ⁰C. The flashover stage also occurred in the 5th to 9th minute with regular results close to 500 ⁰C.

Numerical analysis of the effect of roof types and porch on particle dispersion and deposition around a low-rise building

Outdoor air quality demonstrates one of the major challenges for preserving human health and the environment and also involves the indoor environment of buildings. Accordingly, besides urban morphology, building form should be considered as a passive strategy to reduce regional particle deposition and dispersion. In this framework, this study numerically pursues the influence of building shape on improving outdoor air quality around buildings. For this pursuit, eight cases of low-rise buildings with different roof types and a porch at different heights are compared with a simple building form with a flat roof to examine their impact on airflow and particle dispersion and deposition around low-rise buildings. The RNGk−ε turbulence model, in line with the discrete particle model (DPM) is implemented to model particulate flow and investigate particle dispersion and deposition. The discrete random walk (DRW) model is used to simulate the turbulent particle concentration. The results confirm that the combination of shed roof and porch can reduce the amount of particle deposition on the downstream wall of the building by about 20% less than the building with a flat roof. Moreover, using a porch at different heights integrated with a flat roof accumulates more particles on the downstream wall. Evidently, the vortex size influences particle concentration around buildings depending on the building shape. These findings will be helpful for designers regarding the impact of porch and roof types to improve outdoor air quality around buildings. Additionally, these promotions can be employed for decreasing particle deposition on buildings’ walls.

DESIGN PHASE OF A CYLINDRICAL LONG-SPAN COAL SHED WITH STEEL ARCH SPACE-TRUSS STRUCTURE

<p class="Text">This paper discusses the structural design phase of a long-span coal shed structure in a 2x50 MW steam power plant. This study aims to share knowledge on how to design a long-span coal shed structure safely based on the design standards. The main structural system of the coal shed roof is a steel arch space-truss with 120 m of span and 31 m of height above supporting 12.5 m height of reinforced concrete columns. The superstructure contains a roof system and reinforced concrete system. The substructure system consists of a tie beam, pile cap, and bore pile. In the numerical model, all structural members were idealized as frame elements, except the pile cap that to be idealized as shell elements. Then, the soil springs were assigned to the bore pile element nodals with a 1 m interval to simulate the soil-structure interaction. The gravity loads due to dead loads, additional dead loads, live loads, rain loads, and lateral loads due to wind action and earthquakes to be considered. Furthermore, the structural analysis was conducted with non-linear geometric to simulate the large displacement effects and tension only element of the wind bracing. In addition, a simplified method to estimate the structural stability under lateral load was conducted. Based on the structural analysis and structural design, the coal shed structure could fulfill the safety criteria in terms of ultimate and serviceability limit based on the design code criteria. Furthermore, the non-linear geometry and stability issue should be considered with an appropriate structural analysis method.</p>

Awareness of Paddy Residue Utilization in Karnal and Kurukshetra Districts of Haryana State

Study was conducted in 2021-22 to assess the awareness level of farmers regarding utilization of paddy residue in Karnal and Kurukshetra districts of Haryana state. A well structured and pre-tested interview schedule was developed according to the objective of the study. Two blocks were selected randomly from each district. Further, one village from each block was also selected randomly. So, four villages were selected to collect data. Further, from each selected village, 75 male paddy growing farmers having more than 5 acres of land were selected through snowball technique. Thus, total 300 respondents were interviewed. Present study concluded that all respondents (100.00%) were aware about straw baler machine and feeding the livestock, followed by making cattle shed roof (96.33%), hey rake (93.67) and mulching in the field (93.67). Study also concluded that sufficient time to sow next crop because it takes one and half months to decompose, paddy straw management delays wheat sowing and paddy residue burning is cheap option were major reasons for paddy residue burning.

Analysis of wind loads in the building with a variation of roof shapes

The Indonesian’s geographical position, which makes Indonesia frequent disasters due to wind, objects unable to withstand the wind can lift or shift these objects. This condition causes damage, such as a roof that is raised or floating. Buildings in Indonesia generally use gable roofs, hip roofs, and one-sided sloping (shed) roofs, while several types of roofs can be used in buildings, such as mansard roofs and curved roofs. This study uses a quantitative approach, which records and analyzes research data and performs data calculations with statistical calculations. This research compares wind loads based on SNI 1727-2013 Minimum Load for Planning of Buildings and Other Structures with different roof shapes in Bandung to determine the effect of each roof shape on wind loads on buildings and obtain roof shapes. With the smallest and largest wind load influence. Based on the research results, the displacement value in the roof structure due to wind loads is 0.025118 m (Hip and Gable), 0.018352 m (One-sided Sloping z1), 0.036073 m (One-sided Sloping z2), 0.027238 m (Mansard), 0.017629 m (Curved). Buildings with curved roofs produce minor wind load effects, and buildings with one-sided sloping roofs have the most significant wind load effects.

Investigation of snow load reduction in the industrial sheds roof design with photovoltaic systems by mathematical modelling, solar system evaluation, X-steel simulation and thermodynamic practices

Since snow load is one of the loads of designing the industrial shed roof, this research presents a new system to reduce the industrial sheds roof design. In this system, sensitive units of moisture and temperature, which can be adjusted with different areas, are installed on the shed’s roof. The mechanism of system is that the sensors in the units detect the presence of snow on the shed roof and send an order to connect electricity to the elements; therefore, the snow on the roof melts by the heat generated. In this system, solar panels are used to supply electricity. As with the help of this mechanism, snow does not remain on the roof, it is possible to eliminate the snow load in the calculations of the shed and apply at least the live load of the sixth regulation (Due to having a one-story shed, minimum live load applied and it used only for the foundation design of the structure.), this issue will create an economic plan in shed designing. According to the study conducted in this research, it is shown that the dimensions of the sheet beam used in the shed are reduced, which will significantly reduce the cost of construction and installation to some extent. In the following, two samples of sheds with a span of 20 meters in the presence of snow and the absence of snow in the software were modelled, and the results were compared with each other.

Field of Vision

Field of Vision Margot Kahn (bio) Feathery as a frayed hem,in the wind the hay field moveslike the tufted manes of a thousandhorses running. No—it moveslike the pleated skirts of a thousand girlsswishing as they walk to school.After school, there was a girl's fieldwe'd crouch down in, curl and shiverlike fawns as someone's legs passed byso close it seemed impossiblethey'd miss you. They were torturesin equal measure: the waitingand the being found. From the edgesof that field, the girl's father whistled—a whistling tune and another soundthat brought the children runningsharp as sheep dogs from the hay fieldor the fronds of the willow tree or the farfence we'd half-climb to watch the horsesin the neighbor's field, pretendingthey were ours. Last week at the post office,the tellers could barely be heardover the thousand chicks cheepingin cardboard boxes behind the counter.Their feathery non-feathers. Their cheepsof being young in a strange placewith only a small hole to see through.I didn't do well in schoolbut I have come to understandthat a bond is only as strong as a breathof air. When I learned that that girlno longer speaks to her father,I thought of her room strung up [End Page 162] with 4-H ribbons, their blue and red tailsfluttering against a floral wall.And when my son crawls into bedwhimpering a fetal cry, broken byhis parents not understanding himfor the first time, I am tender.The hay will be cut tomorrow.The raptors will come circling.We'll watch from the shed roof,where we can see the patternsthe mower cuts in the field. [End Page 163] Margot Kahn Margot Kahn is a poet, essayist, biographer, and editor. She is the author Horses That Buck (University of Oklahoma Press, 2008) and co-editor of the New York Times Editors' Choice anthology This Is the Place (Seal/Hachette, 2017). Her poems have appeared or are forthcoming in Poetry Northwest, Mantis, New Ohio Review, and elsewhere. Copyright © 2021 Middlebury College

Optimizing the solar energy capture of residential roof design in the southern hemisphere through Evolutionary Algorithm

Australia's national energy system is heavily reliant on coal-fired power plants and requires quick action to decrease CO2 emissions in order to meet the Paris climate change agreement by 2030. As a good alternative to coal power, renewable resources can produce the required energy for Australia while keeping the environment clean. The annual amount of falling solar irradiation in Australia is a few thousand times higher than its energy consumption, but the amount of the collected solar energy is unsatisfactory. In Perth, the sunniest city in Australia, one-third of the residential dwellings have roof-mounted solar collector systems. However, there have been limited studies into the integration of these systems in building design and it is still unknown which roof design can deliver maximum efficiency based on the local environmental conditions. Therefore, the aims of this study are to determine the optimum residential roof design in Perth, Western Australia and to maximise extracted solar power throughout a year. To reach this aim, a combination of analytical modelling, numerical simulation, and evolutionary algorithm methods have been selected. At first, a series of detailed mathematical calculations were performed in Excel to find the optimum solar collector mounting settings. In the numerical simulation, the examination was repeated in the Rhino-Grasshopper interface to verify the earlier findings and calibrate the chosen simulation package with the help of parametric architecture. In the last step, a wide range of housing roof shapes has been tested by evolutionary algorithm plugin-Galapagos, to find the optimum roof shape design in the given context. Our results show that, unlike the traditional approach and common belief, a roof shape with a 25-degree tilt angle, 170-175 azimuth angle, and aspect ratio of 1:1.2 is optimum to gain maximum solar gaining annually. Moreover, this study advances the knowledge of solar capturing by suggesting a new parameter -oblique angle- in finding the optimum roof shape design. After evaluating the importance of the mentioned factors, it is found that, after tilt angle, the oblique angle is the most effective parameter in rooftop solar gaining, higher than roof aspect ratio and azimuth angle. In conclusion, our results demonstrate that an ‘oblique shed roof design’ can generate 15.7% higher solar radiation compared to the base case. The findings of this study can be applied by architects, construction companies, and householders to optimize the solar gaining in the future of the residential building in Perth.

Review: Frank Furness: Architecture in the Age of the Great Machines, by George E. Thomas

Review: <i>Frank Furness: Architecture in the Age of the Great Machines</i>, by George E. Thomas

Genetic Algorithm Applied to Multi-Criteria Selection of Thermal Insulation on Industrial Shed Roof

The rational use of energy has motivated research on improving the energy efficiency of buildings, which are responsible for a large share of world consumption. A strategy to achieve this goal is the application of optimized thermal insulation on a building envelope to avoid thermal exchanges with the external environment, reducing the use of heating, ventilation and air-conditioning (HVAC) systems. In order to contribute to the best choice of insulation applied to an industrial shed roof, this study aims to provide an optimization tool to assist this process. Beyond the thermal comfort and cost of the insulation, some hygrothermic properties also have been analysed to obtain the best insulation option. To implement this optimization technique, several thermo-energetic simulations of an industrial shed were performed using the Domus software, applying 4 types of insulation material (polyurethane, expanded polystyrene, rockwool and glass wool) on the roof. Ten thicknesses ranging from 0.5 cm to 5 cm were considered, with the purpose of obtaining different thermal comfort indexes (PPD, predicted percentage dissatisfied). Posteriorly, the best insulation ranking has been obtained from the weights assigned to the parameters in the objective function, using the technique of the genetic algorithm (GA) applied to multi-criteria selection. The optimization results showed that polyurethane (PU) insulation, applied with a thickness of 1 cm was the best option for the roof, considering the building functional parameters, occupant metabolic activity, clothing insulation and climate conditions. On the other hand, when the Brazilian standard was utilized, rock wool (2 cm) was considered the best choice.

Improving the energy production of roof-top solar PV systems through roof design

Australia is receiving an average of 58 million PJ of solar radiation per year, which is about 1000 times larger than its total energy generation. Roof-top solar photovoltaic (PV) systems alone can supply a phenomenal fraction of the nation’s total energy. The architectural design and orientation of roofs have considerable impacts on the energy efficiency of roof-top solar PV systems. These aspects, however, have received scant academic attention within the literature. To address this knowledge gap, this research seeks to increase the energy production of roof-top solar PV systems through roof design. The energy generation of roof-top solar PV systems is modelled using Helioscope software, and then validated using real-time monitored data. Based on the verified model, the impact of different tilt angles and shading from surrounding obstructions upon energy generation are analyzed in detail. To ground the research in practical terms, the aesthetic design of five typical roof design patterns (including flat, shed, gable, hip, and butterfly roof) are explored to compare the energy generated from solar PV systems fitted to each design. Findings indicate that: (1) the simulated energy generation from the solar PV system is close to the monitored data, with equal annual generation; (2) the shading of surrounding obstructions can reduce the energy generation of roof-top solar PV systems considerably, where up to 24% energy loss is reported; (3) the optimal tilt angle is about 35°, which is close to the latitude angle of the studied location; and (4) the shed roof design provides the maximum potential for solar energy generation when compared to that of other roof design patterns. The energy generation variation of other aesthetic roof patterns is also presented, providing support for informed decision making on the roof design. This study contributes to the field through improving the energy production of roof-top solar PV systems based on roof design along with considering aesthetic concerns. Novel insights generated will be beneficial for researchers and government policy makers alike; the work also introduces simulation-based methodological approaches for practitioners who seek to improve the energy generation of roof-top solar PV systems.

Design of inboard first wall for initial operation of JT-60SA

The inboard first wall for initial operation of JT-60SA is installed to protect vacuum vessel and magnetic sensors from plasma, under no-cooling-water condition for in-vessel components. The first wall is designed to withstand forces such as magnetic forces due to eddy and halo currents, acceleration due to plasma disruption and earth quake, and heat loads such as radiation from plasma, limiter configuration and ECRH direct irradiation. The inboard first wall consists of graphite tiles, stainless pedestals and base rails. The base rails are welded on the surface of the inboard vacuum vessel. The stainless pedestals are bolted on the base rails. Two graphite tiles are bolted on each support base. Shed roof shape of graphite tiles is employed to avoid heat concentration at the edge of the tiles and to mitigate heat load during limiter configuration. Thermo-mechanical numerical analyses were carried out, and it was confirmed that the stress was below the design stress against the predicted heat loads and the predicted forces.

Influence of glazing type on energy efficiency of industrial buildings in the process of revitalization: A case study

This paper examines the possibilities of improving the energy performance of an existing industrial building by application of the double skin fa?ade on the revitalization of the building envelope in the climatic conditions of the city Novi Pazar, Republic of Serbia. The aim is to examine the impact of choosing the type of glazing, in the processes of revitalization, on the energy needs of industrial buildings for heating and cooling, as well as the contribution of the measures implemented to improve the energy performance of the selected type and model of industrial building. The energy performance of buildings was obtained using the software DesignBuilder and EnergyPlus simulation platform, taking into account the parameters of required internal temperature and climate data for the Republic of Serbia. The comparative analysis of the results of energy simulation according to the criterion of achieving greater energy savings and reduced carbon dioxide emissions was performed. The methodological approach in this research involves creating revitalization scenarios of industrial buildings with a shed roof construction, selection of the specific building according to whose properties by numerical simulation possibilities for energy revitalization depletion were investigated and comparative analysis of the obtained results was performed. The primary objective of this research is to investigate the impact of choosing the type of glazing on the energy performance of industrial buildings with a shed roof construction and to determine the optimal approach to energy revitalization of existing industrial buildings with the implementation of the double skin fa?ade under the climatic conditions of the city Novi Pazar, Republic of Serbia. The results of this paper indicate the negative characteristics of the kopilit glass to solar gains, whose retention requires a large amount of heating energy. While replacing of kopilit glass with a low-energy glass increases the amount of energy required to cooling of the building. With this research, through various revitalization scenarios, it is also indicated that using a double skin fa?ade in the revitalization process of the selected building, has a very similar impact on reducing CO2 emissions regardless of the type of glazing choice.

Three-dimensional urban solar potential maps: Case study of the i-Scope Project

Solar maps as web cartographic products that provide information on solar potential of surfaces on the Earth have been exploited in decision making, awareness raising, and promoting the use of solar energy. Web based solar maps of cities have become popular services as the use of solar energy is especially attractive in urban environments. The article discusses the concept and aspects of urban solar potential maps on the example of the i-Scope project as a case study. The i-Scope roof solar potential service built on 3-D urban information models was piloted in eight European cities. To obtain precise data on solar irradiation, a good quality digital surface model is required. A cost efficient innovative method for generation of digital surface model from stereophotogrammetry for urban areas where no advanced source data (e. g. LiDAR) exist is developed. The method works for flat, shed and gable roofs and provides sufficient accuracy of digital surface model .

Kimmo in the Pisgah

Kimmo in the Pisgah Sara Read (bio) Click for larger view View full resolution [End Page 26] The man we called Great-Uncle Kimmy lived three-quarters of his life alone in a cabin perched on a mountainside so steep that if you stepped wrong in anger or in drink [End Page 27] you'd wind up in the creek bed deep at the bottom of the holler. There lay the remains (he said) of a Model A Ford, a hundred-year-old still, and two commercial-grade highway lawn mowers. If you wound up down there, you'd never be found, but it wouldn't matter because you'd be dead. No one and nothing (he said) ever went down into the bottom of that holler besides the things meant to by nature, and nothing not meant to go there by nature ever came out. The man we called Great-Uncle Kimmy was also the difference between what became of me and what became of Kate, forget what anybody else says. In October, a month after I turned fifteen, my grandmother dragged me by the shirt from the juvenile courthouse. I only ever called my grandmother "Grandmother," and not because she was kindly and lavender-smelling. She was a scrawny old witch who didn't deserve to be called anything nicer. My nose was broken and throbbing (never, goddamnit, never fall asleep in a girl's bedroom), and Grandmother kept her claws in me as she made a call from the pay phone in the hall. Her conversation was shorter, I think, than she expected it to be. "Hell, no," she said, "I'm not going to bring a blanket. We're coming out there now. You can figure out about a damn blanket. If I have to look at his smart-ass face one more minute, I think I'm going to just kill him and get it done with." Then she hauled me out to her crappy sedan and drove south and west through two or three small towns, past the last Walmart and the last ranch houses and up the mountain. Up the winding road along the crest where the day-trippers brought their motorcycles and expensive cars, up where the overlooks got higher and higher and the views got wider and wider and you couldn't see another road for miles. About two miles and three forks down a steep gravel road was where Kimmy parked his late-model white F150 all-wheel drive. Nice truck, I was thinking when Grandmother stopped and told me to get out. Just like that, with the clothes on my back and a few bucks in my pocket. "You got to walk from here," she said. "Walk where?" "You'll figure it out. Or wait until Kimmy comes down to get you." "What?" She pulled an angry three-point turn and took off. "Fuck you," I muttered. [End Page 28] Someone had put up one of those numbers so the 9-1-1 people can find you, and I figured that must be the way to Kimmy's. I huffed up the path, craving a smoke. I had half a pack in my back pocket that Grandmother hadn't known or cared about—least of my problems at the time, the cigs—and after a few minutes I sat on the ground and lit one. It didn't agree with my lungs, which were heaving to pull some damn oxygen out of the mountain air. I saved the butt, though, because who freaking knew when I'd get to buy another pack. The path forked, and I called out, "Uncle Kimmy?"—but I didn't hear anything besides a kind of dull roar. I followed the roar, and when the path forked two more times, I followed it two more times. Then, where you abso-fucking-lutely could not imagine would be a cabin, there was a cabin. A tight, square-looking two-room cabin with a couple of windows and a stone chimney, set back against a high outcropping of rock. "Anybody home?" I yelled and got a clanging from around back in answer. A shed roof extended...