676 results about "Water cut" patented technology

The invention discloses a drilling and cutting head, a drilling and cutting device, a gob-side entry retaining slotting method and a roof cutting pressure relief method, and belongs to the technical field of mine drilling and cutting. The drilling and cutting head comprises a vehicle body, a drilling rod and the drilling and cutting head, and the vehicle body is rotationally provided with a drilling rod conveying driving mechanism through a connecting base and a rotary table; a water cutting system is further installed on the vehicle body. The drilling and cutting head comprises a mounting seat, a plurality of drill bit seats and drill bit blocks, an inner cavity is formed in one end of the mounting seat, and mounting holes are formed in the side wall of the mounting seat; a spray hole is formed in the middle of the spray head. And the end part of the inner cavity of the drilling and cutting head is connected with the head drill rod. Through one device, two operation procedures of drilling and water cutting can be achieved, high efficiency of the gob-side entry retaining slotting method and the top cutting pressure relief method can be achieved, the device cost is effectively reduced, the device can be flexibly and conveniently used in a roadway, the operation efficiency is effectively improved, and the device cost is reduced.

The invention relates to the field of direct drinking water of a fusion calculation model, and discloses a double-membrane mixing direct drinking water system and an operation method.The method comprises the steps that online data of a water supply end and a water quality monitoring end are collected for cleaning and time alignment, and a basic working condition data set is formed; the method comprises the following steps: establishing an operation characteristic model comprising water demand prediction, raw water quality prediction and membrane flux characteristic sub-models, calculating double-membrane target water yield and water quality indexes based on the model to generate a control parameter set, evaluating membrane pollution to generate an online cleaning task queue, performing joint simulation to generate a pressure stability control instruction set, and dynamically correcting the model. The conversion from passive response to active pre-judgment of the double-membrane mixing direct drinking water system is realized, and the operation stability, the water quality guarantee capability and the water-saving and energy-saving effects are improved.

The invention relates to the technical field of underground water prevention and control, in particular to a tunnel two-step grouting plugging method for wide crack water gushing, which comprises the following steps of: constructing a grouting hole intersected with a wide crack or a concentrated water gushing channel according to a geological survey result; first rapid plugging slurry is injected into the crack through the grouting hole, and the first rapid plugging slurry can form a temporary water stopping barrier in the flowing water environment; the water outlet amount change and the grouting pressure change of the adjacent observation holes are monitored, and when the water outlet amount is remarkably reduced and / or the grouting pressure stably rises and forms a platform, it is judged that the temporary water stop barrier is formed; and second reinforcing grout is injected into the crack through the grouting holes, and after the second reinforcing grout is solidified, a permanent reinforcing body with mechanical strength is formed. By optimizing the grouting material and the process time sequence, effective combination of rapid plugging and long-term reinforcement is achieved, the grouting reliability is improved, and the engineering cost is reduced.

The invention discloses a water injection regulation and control method based on deep reinforcement learning under data and model fusion driving, and the method comprises the following steps: collecting operation parameter data under an oil field injection-production working condition, and carrying out the data preprocessing; a model-free water injection regulation strategy is designed, a traditional oil yield prediction model is removed, and a water injection action is directly generated based on an environment state by constructing a state-action space containing the parameters; a soft actor-commentator (SAC) algorithm and a long short-term memory network (LSTM) collaborative decision framework are adopted, an oil reservoir parameter time sequence rule is captured by using LSTM to provide state prediction for SAC, and water injection and oil extraction joint debugging of a well group is optimized in combination with a state-driven dynamic reward function; a priority experience playback mechanism is introduced to optimize SAC training, and the action generation efficiency is improved. According to the model constructed by the method, the calculation complexity is remarkably reduced, the oil production is improved, the water content is reduced, and the method has relatively high practical value and economic benefits and is particularly suitable for water injection regulation and control scenes under complex oil reservoir conditions.

The invention provides an intelligent water affair data management method and system, and the method comprises the steps: determining adjacent leakage points through a distribution density change direction, recognizing a pressure gradient between the adjacent leakage points, and determining a single-point water yield correction proportion; checking the single-point water yield correction proportion and the instantaneous flow value in the leakage point related data set to obtain a flow deviation value, identifying the type of the leakage point according to the flow deviation value and the flow fluctuation characteristics, and adjusting a leakage contribution degree evaluation weight table according to the type of the leakage point; summarizing the total leakage water quantity from the classified real leakage water quantity components, analyzing a change rate in combination with historical total leakage water quantity data, evaluating whether the change rate reflects a total water quantity reduction phenomenon under the condition that the number of leakage points is increased or not, and obtaining a total leakage water quantity verification result; and according to a total leakage water quantity verification result, the partition pressure data and the distribution density change trend are integrated to generate a pipe network health assessment report, and the overall accuracy improvement degree is assessed through an accumulated value of a real leakage water quantity component in the report.

The invention belongs to the technical field of mine engineering, and particularly discloses a dynamic simulation method for water inflow attenuation in the construction process of a water cut-off curtain of a strip mine. The method comprises the following steps: acquiring meteorological data according to the position of a strip mine, acquiring a hydrogeological structure in combination with drilling data, acquiring hydrogeological parameters by using a water pumping test, and acquiring a source convergence item according to water pumping and drainage; the method comprises the following steps: constructing a hydrogeological model by adopting MODFLOW-USG, constructing a mine pit drainage mathematical model and a mine pit drainage model, setting source sink items and boundary conditions, and realizing dynamic simulation based on python; a PEST calibration model is adopted, parameters are subjected to standardization processing, a random forest substitution model is constructed, SHAP values of all the parameters are analyzed and calculated and normalized to obtain global importance indexes, and the model is optimized; and evaluating the optimized model by adopting NSE, KGE and RMSEs. The method has the advantages of being high in model precision, clear in parameter physical significance and capable of being corrected with measured data in real time.

The invention relates to the technical field of foundation pit engineering construction, in particular to a foundation pit drainage optimization method and system based on water level monitoring. Comprising the steps that precipitation partitions are divided according to geological conditions and a construction scheme, and precipitation wells and observation wells are arranged; determining differentiated target water level drop depth according to the excavation depth and the support state; establishing an inter-partition hydraulic coupling model through a pulse water pumping test, and determining coupling kernel function parameters; predicting the future water level change through convolution operation based on the coupling kernel function and the historical water yield; calculating an optimal water yield sequence by adopting a rolling time domain optimization method, and taking the minimum accumulated water yield as a target and meeting the target water level drop as a constraint; controlling the operation power of the water pump and implementing cooperative compensation; coupling kernel function parameters are periodically updated to adapt to system changes. The rainfall control precision is improved, the energy consumption is reduced, and the construction safety is guaranteed.

The embodiment of the application provides a gravity self-balancing uniform water distribution system, which comprises first, second and third stage gravity self-balancing water distribution pipelines. Each second stage gravity self-balancing water distribution pipeline is connected to the first stage gravity self-balancing water distribution pipeline, and each third stage gravity self-balancing water distribution pipeline is connected to the second stage gravity self-balancing water distribution pipeline. The circulating water of the cooling tower is automatically depressurized after entering the first stage gravity self-balancing water distribution pipeline, and flows into each second stage gravity self-balancing water distribution pipeline on the basis of the self-weight of the water to realize double uniform water distribution. The water level height of each second stage gravity self-balancing water distribution pipeline is consistent, and the water inlet flows to the third stage gravity self-balancing water distribution pipeline again. The pressure at each water nozzle directly or indirectly connected to the third stage gravity self-balancing water distribution pipeline is consistent, and the water outlet of each water nozzle and the spraying area are substantially the same, so that uniform water distribution is realized, the water inlet is not affected by the water pressure, and the cooling efficiency of the cooling tower is significantly improved.

A system may include a lower completion disposed in a main bore of a multilateral well in a position downhole from a junction of the multilateral well. The system may also include a fluid separator configured to receive formation fluid, which includes oil and water, flowing from the lower completion. The fluid separator may be configured to at least partially separate the formation fluid into formation oil and formation water. The fluid separator may also be configured to output the formation oil, via a separator oil outlet, to flow uphole, and output the formation water, via a separator water outlet, to flow toward a lateral bore of the multilateral well. Further, the system may include a water cut sensor disposed uphole from the fluid separator. The water cut sensor may be configured to measure the percentage of water in the formation oil.

The application discloses an intelligent identification method for dominant seepage channels based on big data, which comprises the following steps: collecting static geological data, dynamic development data and dynamic monitoring data of an oil reservoir and performing data processing; performing data quality analysis on the processed data and establishing a sample database; performing inter-well connectivity analysis and inter-well pressure response analysis in a plane according to the sample database, and identifying dominant channels in the plane; performing interlayer production and absorption law research in a vertical direction according to the sample database, predicting interlayer liquid production and absorption ratios and water cut, and identifying dominant interlayer positions in the vertical direction; and comprehensively identifying dominant seepage channels between each layer of a production well and an injection well based on the identified dominant channels in the plane and the dominant interlayer positions in the vertical direction.

A system for enhancing oilfield performance analysis and optimization, comprising a data collection module configured to collect real-time Gas-Oil Ratio (GOR) and Water Cut (WC) data from oilfield sensors a physics-based modeling module configured to simulate a vertical pressure profile based on the collected GOR and WC data, and a machine learning module configured to analyze outputs from the physics-based modeling module and historical data, classify wells based on the analysis, establish baseline metrics for evaluating reservoir productivity based on the analysis and classification, generate a recommendation for well operations based on the analysis, classification and baseline metrics, and a user interface configured to display the recommendation.

The invention relates to a water balance regulation and control method and device for a power plant, electronic equipment and a storage medium, and the method comprises the steps: inputting the multi-source operation data of a current power plant water system into a preset time sequence prediction model, outputting a water quantity prediction result, and based on a preset multi-target optimization algorithm, according to the current unit operation state and the water quantity prediction result, obtaining a water balance regulation and control result; obtaining a target control strategy meeting a preset constraint condition; inputting the current wastewater quality and quantity information into a preset wastewater scheduling model for wastewater utilization planning, and generating a target wastewater utilization strategy; and generating a target control instruction according to the target control strategy and the target wastewater utilization strategy, and issuing the target control instruction to an execution mechanism so as to control the execution mechanism to perform a corresponding adjustment action based on the target control instruction. Therefore, the static, isolated and extensive defects of existing coal-fired power plant water system management are overcome, the unit power generation water taking amount is remarkably reduced, the comprehensive utilization efficiency of water resources is improved, and the method adapts to the complex operation working conditions such as deep peak regulation.

The invention discloses a neural network-based water drive oil field dominant channel grade identification method, which comprises the following steps of: acquiring multi-source data of an oil field injection and production well, including multi-dimensional information such as liquid production capacity, oil production capacity, water content, working fluid level, perforation information, production and absorption profile, tracer response and the like; longitudinal multiple parameters, time evolution characteristics and spatial distribution relations are fused to construct a multi-modal data set; a multi-input neural network structure is designed, a multi-layer perceptron is adopted to extract time sequence features of structured data, a graph convolutional network is adopted to extract geological map features, and cross-modal fusion is realized in combination with a feature splicing module; a causal inference mechanism is introduced, the causal effect between injection and production wells is estimated through attention weight and anti-factual inference, and the dominant channel level is quantified. The method can effectively improve the recognition capability of dominant channels under a complex injection-production relation and a heterogeneous geologic structure, has high practical value and popularization potential, and is suitable for profile control optimization and injection-production structure adjustment tasks of various water drive oilfields.

The utility model discloses a portable water purifier. The portable water purifier comprises a filtering unit and a power device, wherein the filtering unit comprises a raw water inlet and a purified water outlet; the power device comprises a shell and at least one piston movably arranged in the shell, two pressure cavities are defined by the piston and the shell, each pressure cavity is correspondingly provided with a raw water inlet and a raw water outlet, the raw water outlet is communicated with the raw water inlet, and the piston moves back and forth in the shell to enable each pressure cavity to be switched between a negative pressure state and a positive pressure state; and in the back-and-forth movement process of the piston, one of the two pressure cavities is in a negative pressure state, and the other pressure cavity is correspondingly in a positive pressure state. According to the portable water purifier provided by the invention, in the back-and-forth movement process of the piston, the two pressure cavities alternately convey raw water to the filtering unit, so that the filtering unit can continuously discharge water, the problem of discontinuous water discharge is solved, the water discharge flow is favorably increased, the water discharge amount in unit time is large, and the operation is more time-saving and labor-saving.

The utility model discloses a corn planter with an automatic watering structure, and relates to the technical field of corn planters, a water storage tank is of a hollow box type structure, and the bottom end of the water storage tank is in through connection with a plurality of water outlet pipes at equal intervals; the plurality of through pipes are respectively arranged on the outer ring walls of the corresponding water outlet pipes in a penetrating manner; one end of each blocking rod is movably inserted into the corresponding through pipe, and the end of each blocking rod abuts against the inner wall of the water outlet pipe in a matched mode; the multiple limiting rings are fixedly arranged on the ring wall of the other end of the plugging rod, the multiple springs are arranged on the plugging rod, and the two ends of the springs are connected with the through pipe and the limiting rings correspondingly; the adjusting assembly is arranged on the rotating rod, and the adjusting assembly is connected with the end part of the plugging rod; movement of the blocking rods is controlled through the adjusting assembly, the water outlet amount of the water outlet pipe is quantitatively controlled, and quantitative seed irrigation is facilitated.

The invention relates to the technical field of pipeline power generation, and particularly discloses a pipeline power generation device, comprising: a power generation impeller, the power generation impeller comprising a rotating turbine and a rotating shaft, the power generation impeller enabling the rotating turbine to drive the rotating shaft to rotate through flow impact of a medium in a pipeline; an output shaft of the generator is in transmission connection with a rotating shaft of the power generation impeller; the mounting mechanism is used for mounting the power generation impeller on a pipeline and enabling a rotating turbine in the power generation impeller to be in contact with a medium in the pipeline, and the mounting mechanism comprises a mounting pipe communicated with the pipeline; according to the device, the fixed arc plate and the butt joint arc plate are matched with the mounting pipe, so that the water leakage position of the pipeline can be effectively maintained, namely, while the device is convenient to maintain the pipeline, a sensor, a power generation impeller, a power generator and other structures can be effectively mounted to monitor the pipeline, and special water cut-off for mounting the sensor or a power generation device is not needed.

The utility model relates to the technical field of valves, in particular to a water flow regulating valve which comprises a valve body, an inner cavity is formed in the valve body, a water outlet pipe communicated with the inner cavity of the valve body is arranged on the valve body, and a first through hole and a second through hole are formed in the top surface and the bottom surface of the valve body respectively in a penetrating mode. The first through hole and the second through hole are coaxially formed, a water inlet pipe is coaxially fixed at the second through hole, the inner end of the water inlet pipe is sealed, a plurality of water outlet holes are formed in the water inlet pipe in the inner cavity in a penetrating mode in the circumferential direction, a movable pipe is coaxially fixed in the first through hole, and the inner end of the movable pipe extends into the inner cavity and is arranged on the water inlet pipe in a sleeving mode; the movable pipe is in transmission connection with a driving mechanism. By controlling the up-and-down moving distance of the movable pipe, the number of the water outlet holes in the water inlet pipe shielded by the movable pipe can be controlled, so that the water outlet amount of the water inlet pipe through the water outlet holes is controlled, the water outlet flow of the water outlet pipe is adjusted, and more accurate flow control is achieved.

The invention relates to the technical field of industrial control systems, and particularly discloses a selenium-rich water equipment water yield control system based on neural fuzzy control. The system comprises a data acquisition module, a neural fuzzy control module, an actuator driving module and an online learning and parameter adjustment module, fuzzy rules and membership parameters are dynamically optimized through a neural network, a gradient descent algorithm and a working condition memory unit are combined, high-precision self-adaptive control over the water yield is achieved, and the response speed and stability of the system are improved.

This invention belongs to the technical field of waterjet cutting machines, specifically relating to a portable waterjet cutting machine, including a pressurizing device, a sand control device, and a water gun, which are connected by pipelines. It also includes a water gun driving device, comprising a chassis, a water gun fixing assembly, and a drive motor. Support wheels are rotatably connected to the chassis; a support plate is fixedly connected to the chassis, and a drive sprocket is rotatably connected to the support plate; the chassis is connected to the support sprocket via the support assembly, and a chain connects the drive sprocket and the support sprocket; the chassis is equipped with a magnetic suction assembly. By providing the magnetic suction assembly, the chassis can be firmly attached to the pipe to be cut during installation without manual assistance; after the chain is wrapped around the pipe, the attachment is released, ensuring stable movement of the chassis along the pipe, achieving quick and convenient installation and preparation for operation.

The invention provides a water-saving valve device for duck egg cleaning, and belongs to the technical field of duck egg cleaning, the water-saving valve device comprises a plurality of water-saving assemblies, and each water-saving assembly is configured to accurately clean duck eggs and save water resources. The water-saving assembly comprises a sleeve used for conveying water flow for cleaning. The water conveying ball is movably arranged at the front end of the sleeve and configured to adjust the direction of sprayed water flow, and a water spraying groove is formed in the middle of the water conveying ball and used for spraying out water; the rotating ring is rotationally arranged outside the sleeve, movably connected with the water conveying ball and configured to drive the water conveying ball to rotate to a designated position; and the barrier strip is movably arranged at the upper part of the water spraying tank and is used for changing the water yield of the water spraying tank. The rotating ring drives the water conveying ball to rotate in the sleeve, the direction of water flow sprayed out of the water spraying groove in the top of the water conveying ball can be changed, then fixed-point cleaning is conducted on different positions of duck eggs, fixed-point cleaning can be achieved, and meanwhile water resources are saved.

A strip ice machine comprises a plurality of ice buckets and a water injection pipe frame for injecting water into the ice buckets, the water injection pipe frame comprises a water conveying pipe, a plurality of electric push rods are fixedly installed on the water conveying pipe, the same support is fixedly installed on the electric push rods, a plurality of vertical pipes are installed on the water conveying pipe in a communicated mode, and one side of each vertical pipe is communicated with a water outlet pipe. The ice bucket is simple in structure and ingenious in conception, the water outlet pipe of each ice bucket can be independently controlled, when the water level in the ice bucket meets the requirement, the floating ball can move upwards under the action of buoyancy until the rubber sealing plug blocks the corresponding vertical pipe, and the corresponding water outlet pipe does not discharge water any more, so that overflow caused by continuous water injection of the ice bucket is avoided, and the service life of the ice bucket is prolonged. After one vertical pipe is blocked, the water outlet amount of the other water outlet pipes can be increased, and water injection of the other ice buckets is accelerated; and the device can also ice ice blocks with different sizes by adjusting the extending length of the threaded rod and adjusting the water injection amount of the ice bucket, so that the practicability is improved, the actual requirements can be met, and the device is suitable for popularization.

The invention discloses sewage circulation treatment equipment for a water conservancy project, and relates to the technical field of sewage treatment. The garbage can comprises a can wall, and a filtering mechanism is arranged in the can wall. Sewage is introduced into the barrel wall through the water inlet pipe, and along with continuous introduction of the sewage, the water level in the barrel wall gradually rises, so that the sewage enters the filter cartridge I and then flows between the partition plate II and the partition plate I, impurities in the sewage are filtered through the filter cartridge I, and the impurities are deposited on the inner wall of the filter cartridge I; filtered water flows into an external pipe through a first electric valve and a water outlet pipe and then is discharged out of the device, when filtering is continuously carried out, impurities on the inner wall of the first filter cartridge are gradually increased, and consequently the water outlet amount in the first filter cartridge is gradually reduced, and the problem that the device is blocked after being used for a long time is effectively solved through the arrangement of the assembly. And the effect of automatically cleaning the device can be achieved, meanwhile, the cleaning cost is reduced, and the corresponding cleaning efficiency is improved.

The utility model provides a drip irrigation emitter for blueberry planting, which relates to the technical field of blueberry planting and comprises a water tank and a cover plate. The water containing tank is fixedly arranged in soil and is provided with a plurality of water outlet holes; the cover plate is rotatably arranged on the water containing tank in a covering mode and provided with a plurality of plugs, the cover plate is rotated to drive the plugs to plug different numbers of water outlet holes, and a multi-gear water outlet amount adjusting structure is formed. The water containing tank and the cover plate are annular and hollow in the middle, a plurality of inserting rods used for being inserted into soil are arranged at the bottom of the water containing tank, blueberry plants are arranged at the hollow positions of the water containing tank and the cover plate in a sleeving mode, the inserting rods are inserted into the soil, and water outlet holes in the bottom of the water containing tank are formed around the plants. The water can be adjusted according to different plant water demands, and the operation is simple and convenient.

This product is a watering nozzle head that can discharge water from the water inlet at the tip when connected to a water supply hose. The water flow can be turned on or off by operating the lever. The water discharge volume can be switched by rotating the dial.

A hydroelectric power generation system (10) is provided with: a flow path (11) through which water flows and which has a reservoir (102) on a downstream side; a power generation unit (12) which converts the energy of water (W) flowing through the flow path (11) into electric power; an electric valve (13) which adjusts a flow rate of the water (W) flowing through the flow path (11); and a control unit (14) which controls the electric valve (13) on the basis of a target value. The control unit (14) selects the target value from two or more preset setting values, and the two or more setting values include a first setting value that is greater than a maximum value of an outflow flow rate (Q2) from the reservoir (102).

The invention relates to the technical field of water cooling towers, in particular to a multi-valve control system based on a water cooling tower and a using method thereof.The multi-valve control system comprises the water cooling tower and a heat exchange frame arranged in the water cooling tower, and further comprises a spraying adjusting module and a water spraying frame installed in the water cooling tower; a second valve is rotationally mounted in the second mounting frame, and the rotating direction of the first valve is perpendicular to that of the second valve; and the detection module comprises a plurality of first detection strips and second detection strips which are arranged in the water cooling tower, and is used for adjusting the water yield of the first valve and the second valve. The valves are divided into two groups, the swinging directions of the two groups of valves are perpendicular to each other, and different valves are driven to swing according to different swinging directions of the water spraying frame, so that the spraying range is expanded, the spraying uniformity is improved, heat at different positions is detected by utilizing the detection module, the water inlet amount of the valves is changed according to the heat, and the water spraying efficiency is improved. And the uniformity and the efficiency of heat dissipation are further improved.

This utility model relates to an intelligent water temperature control module, characterized by comprising a flow regulation module, a pressure balancing module, and a temperature control module. The flow regulation module includes a first valve seat and a flow regulating valve core. The first valve seat has a first cold water inlet channel, a first hot water inlet channel, a flow regulating valve core mounting cavity, a first cold water outlet channel, and a first hot water outlet channel. The pressure balancing module includes a second valve seat and a balancing valve core. The second valve seat has a second cold water inlet channel, a second hot water inlet channel, a balancing valve core mounting cavity, a second cold water outlet channel, and a second hot water outlet channel. The temperature control module includes a third valve seat and a temperature control valve core. The third valve seat has a third cold water inlet channel, a third hot water inlet channel, a temperature control valve core mounting cavity, a mixing chamber, and a mixed water outlet channel. Each module exists independently and is independently controlled, simplifying the control method, reducing control and manufacturing difficulty, improving the control accuracy of water flow and temperature, and allowing for selection and combination of different modules.

The utility model provides a kind of water cutting equipment with lifting door system and water cutting equipment, it is related to water cutting equipment technical field, comprising: rack, lift door plate, driving device, several counterweight units;Wherein, counterweight unit includes pull rope, counterweight, guide pulley;Guide pulley is installed on rack;Pull rope passes through guide pulley, one end is connected with the upper end of lift door plate, the other end is connected with counterweight, to make lift door plate and counterweight hang and set on guide pulley;Driving device can drive lift door plate to lift to realize opening or closing.This application technical scheme utilizes counterweight to balance the weight load of lift door plate, so that driving device can more stably drive lift door plate to lift to realize opening or closing, effectively avoid the door body damage caused by imbalance, improve safety performance, reduce noise level.

The present application relates to a kind of oil well water cut prediction method and system based on multi-scale knowledge distillation, it is related to oil and gas field development engineering technical field, to solve the problem of complex oil well water cut evolution mechanism, injection-production response hysteresis in oilfield development is strong.Method obtains oilfield block production, injection and well location relationship data, constructs oil-water well time sequence dynamic characteristics after preprocessing;Through lag correlation analysis, the optimal time lag and dynamic weight between wells are obtained, and the dynamic weighted effective injection characteristics suitable for history and future are constructed;Time sequence sample is constructed and dataset is divided according to time, soft label and dynamic representation are output by training multi-scale teacher model fusion, student model is constructed and aligned with teacher and student samples, and knowledge distillation training is completed by multi-loss self-adaptive supervision;Water cut prediction, index deduction and water cut risk early warning are realized by using student model.The present application effectively balances prediction accuracy and reasoning efficiency, improves the accuracy of oil well water cut time sequence prediction, and provides support for oilfield injection development control.