Direct shear test machine: Unveiling the secrets of soil strength, this machine is the unsung hero of geotechnical engineering, quietly revealing the inner workings of the earth beneath our feet. From understanding the very foundation of our structures to predicting the stability of slopes, it plays a critical role. Imagine a miniature battlefield where soil particles grapple, revealing their ultimate strength – that’s the essence of a direct shear test.
Let’s dive into this fascinating world, exploring its history, types, operation, and applications.
This detailed guide delves into the intricacies of direct shear test machines, providing a comprehensive overview from fundamental principles to practical applications. We’ll explore the various types available, highlighting their specific strengths and limitations. The importance of accurate data acquisition and analysis will be emphasized, showcasing how this data informs critical decisions in civil engineering and beyond. Discover how these machines are used to understand soil behavior, predict failures, and ensure the safety and stability of projects.
Introduction to Direct Shear Test Machines
A direct shear test machine is a crucial piece of equipment in geotechnical engineering. It’s designed to measure the shear strength of soil or rock samples under controlled conditions. This understanding is vital for many applications, from designing stable foundations to predicting the behavior of slopes. Essentially, it simulates the forces that cause materials to fail in a controlled setting.This method provides insights into how soil and rock react when subjected to stress, aiding in the design of structures that interact with these materials.
By applying controlled shear stresses, engineers can determine the strength parameters necessary for accurate design. The insights derived are essential for ensuring stability and safety in projects involving soil and rock.
Purpose of Direct Shear Tests
Direct shear tests are used extensively in geotechnical engineering to evaluate the shear strength characteristics of soil and rock samples. They provide crucial data for various applications, including slope stability analysis, foundation design, and pavement design. The results help engineers understand how soil and rock behave under different stress conditions, ensuring the safety and stability of structures built upon them.
The tests yield specific shear strength parameters, which are critical inputs in many geotechnical design calculations.
Fundamental Principles of the Direct Shear Test
The direct shear test method relies on the principle of applying a controlled shear stress to a soil or rock sample. A sample is placed between two surfaces, and one surface is moved relative to the other. The shear stress is gradually increased until failure occurs. The shear strength is determined from the peak shear stress and the corresponding shear displacement.
The test isolates the shear stress component, allowing precise measurement of this critical parameter. This method isolates the shear stress from other stresses, allowing precise measurement of this critical parameter.
History of Direct Shear Test Machines
The development of direct shear test machines is rooted in the need to understand the mechanical behavior of soil and rock. Early forms of these devices likely emerged in the early to mid-20th century, evolving alongside the growing field of geotechnical engineering. These early machines were often simpler in design, but they provided essential data for design and analysis.
The continuous refinement and advancement of these machines have led to sophisticated instruments capable of performing accurate and precise tests. This progress has been essential to the advancements in geotechnical engineering.
Key Components of a Direct Shear Test Machine
Understanding the components of a direct shear test machine is essential for appreciating its function. These components work in concert to apply controlled shear stresses and measure the resulting shear strength. The machine is designed for precision and accuracy.
| Component | Function |
|---|---|
| Shear Box | Holds the soil sample and applies the shear stress. |
| Loading Frame | Provides the controlled force to cause shear failure. |
| Displacement Measuring System | Measures the relative movement between the two shear surfaces. |
| Pressure Measuring System | Measures the normal stress applied to the sample. |
| Control System | Controls the rate of loading and measurement of displacement and stress. |
Types of Direct Shear Test Machines
Direct shear testing, a cornerstone of geotechnical engineering, involves meticulously measuring the shear strength of soil and rock samples. Choosing the right direct shear test machine is crucial for obtaining reliable and accurate results. Understanding the different types available and their specific capabilities is vital for appropriate application in various geotechnical projects.Different direct shear test machines cater to varying project requirements, from small-scale laboratory experiments to large-scale field investigations.
These machines vary in size, capacity, and features, each optimized for specific testing needs. Consideration of these factors is essential to ensure accurate and reliable results.
Categorization by Size and Capacity
Different sizes and capacities of direct shear test machines cater to diverse testing needs. Small-scale machines are ideal for smaller samples and basic research, while larger machines can handle larger samples for more complex and extensive investigations. The choice depends on the scale and scope of the project.
- Small-Scale Machines: These machines, often found in university labs and smaller testing facilities, are designed for smaller sample sizes and controlled laboratory environments. Their compact size and lower price point make them accessible for educational purposes and preliminary research. They are typically less expensive and easier to maintain compared to large-scale machines.
- Medium-Scale Machines: These machines are more substantial than small-scale machines, accommodating larger samples and higher testing loads. They are suitable for routine geotechnical investigations, quality control checks, and various engineering applications. These machines offer a balance between cost and capacity.
- Large-Scale Machines: These robust machines are capable of handling exceptionally large samples and extremely high loads, making them crucial for projects requiring extensive testing, such as large-scale infrastructure projects or specialized research studies. They are often employed in situations demanding greater accuracy and precision.
Features and Considerations
Beyond size and capacity, the features of direct shear test machines significantly impact their suitability for different applications. Automation, data acquisition systems, and safety mechanisms play a critical role in ensuring reliable and accurate results.
- Automation and Data Acquisition: Automated systems allow for precise control over testing parameters, like loading rates and displacement. Sophisticated data acquisition systems enhance the reliability and accuracy of the results. These systems often provide real-time data, facilitating better analysis and decision-making.
- Safety Mechanisms: Safety mechanisms, including overload protection and emergency stop systems, are crucial for preventing accidents and ensuring the well-being of the operator. Modern machines incorporate robust safety measures for enhanced operator safety.
- Control and Monitoring Systems: Direct shear test machines equipped with advanced control and monitoring systems offer enhanced precision and control during the testing process. These systems ensure accurate and reliable results.
Comparison Table
| Machine Type | Sample Size (approximate) | Load Capacity (approximate) | Features | Applications |
|---|---|---|---|---|
| Small-Scale | 100-500 cm3 | 10-100 kN | Manual control, basic data acquisition | Laboratory research, small-scale projects |
| Medium-Scale | 500-2000 cm3 | 100-1000 kN | Automated control, data logging | Routine testing, quality control |
| Large-Scale | 2000+ cm3 | 1000+ kN | Advanced automation, remote control, high precision | Large-scale infrastructure projects, specialized research |
Specific Models and Brands
Several reputable manufacturers offer direct shear test machines, each with its own range of models. Examples include [Manufacturer A]’s Model X, known for its robust construction and reliable performance, and [Manufacturer B]’s Model Y, which excels in its automated control features. Researching specific models can reveal crucial details about their capacity, features, and price range.
Operating Principles and Procedures: Direct Shear Test Machine
Unveiling the secrets of the direct shear test, we embark on a journey through its operating principles and procedures. Understanding these nuances is crucial for accurate and reliable soil analysis. The direct shear test, a cornerstone in geotechnical engineering, allows us to precisely determine the shear strength parameters of soil.The direct shear test machine is a sophisticated instrument designed to meticulously evaluate the shear strength of soil under controlled conditions.
The machine applies a gradual and precisely controlled shear stress to a soil sample, enabling engineers to assess the soil’s resistance to failure. This data is vital in designing and constructing various civil engineering projects.
Operating Mechanism
The direct shear test machine comprises a rigid upper and lower shear box. The soil sample, carefully prepared, is sandwiched between these two plates. A controlled normal load is applied to the sample, simulating the stress it would experience in the field. As the upper box is gradually displaced, the shear stress acting on the sample increases. The machine measures this shear stress and the corresponding displacement, enabling engineers to determine the shear strength parameters of the soil.
The precise control over these variables allows for repeatable and reliable results.
Sample Preparation
Proper sample preparation is paramount for accurate results in a direct shear test. This involves meticulously selecting, trimming, and preparing the soil specimen to ensure uniformity and representativeness. The sample must be representative of the in-situ soil conditions, free of large stones, roots, or other foreign materials. The sample is then carefully placed within the shear box, ensuring no air voids are present and maintaining its natural moisture content.
The preparation process is critical, influencing the reliability of the entire test.
Testing Procedures
A step-by-step procedure for conducting a direct shear test will now be presented. Accurate adherence to these steps is crucial for obtaining reliable and repeatable results.
- Preparation: Select a representative soil sample, trim it to fit the shear box, and place it within the box, ensuring proper compaction and no air voids.
- Normal Load Application: Apply the pre-determined normal load to the sample using the machine’s loading mechanism. This simulates the actual stress on the soil in the field.
- Shear Stress Application: Gradually and uniformly apply the shear stress to the upper shear box. The machine continuously records the shear stress and displacement.
- Data Acquisition: The machine diligently records the shear stress versus the displacement data. This data is critical in evaluating the shear strength characteristics of the soil.
- Results Analysis: Analyze the collected data using appropriate methods to determine the shear strength parameters of the soil, such as the shear stress at failure and the corresponding normal stress.
Setting Up the Machine
Setting up the machine for testing requires careful attention to detail. Ensuring the machine is calibrated and properly positioned is crucial. The following steps Artikel the process:
- Verify the machine’s calibration and ensure all components are functional.
- Position the shear box assembly, ensuring its alignment and stability.
- Place the soil sample within the shear box, carefully compacting it to eliminate any air voids.
- Apply the pre-determined normal load to the sample, checking the dial readings to ensure accuracy.
- Initiate the shear stress application mechanism, observing the machine’s operation throughout the test.
Applying Controlled Shear Stress
Applying controlled shear stress is crucial for a direct shear test. The machine’s design allows for gradual and precise application of shear stress, preventing sudden movements and enabling accurate measurement. The machine’s mechanism ensures that the upper shear box moves at a constant rate, allowing for consistent and reliable measurements of shear stress versus displacement. This data is critical for understanding the soil’s shear strength characteristics.
Data Acquisition and Analysis
Unveiling the secrets of soil and material interaction requires meticulous data acquisition and insightful analysis during direct shear testing. Precise measurements and careful interpretation of the collected data are crucial for understanding the behavior of materials under shear stress. This section delves into the methods employed to gather and analyze this critical information.
Data Acquisition Methods
Direct shear testing relies on a combination of mechanical and electronic systems to gather the required data. Sensors, typically strain gauges or load cells, are strategically placed to monitor crucial parameters. These sensors convert physical quantities like force and displacement into electrical signals, which are then digitized and recorded. Advanced systems employ sophisticated data acquisition systems to record and process the data in real-time.
This allows for continuous monitoring and adjustment of the testing conditions, leading to more accurate and reliable results.
Parameters Measured
Several critical parameters are meticulously measured during a direct shear test. These parameters provide a comprehensive picture of the material’s response to shear stress. The shear force, acting tangentially on the specimen, is a primary parameter. Normal stress, applied perpendicular to the specimen, is equally important in understanding the interaction between the soil and material. Displacement, measuring the relative movement of the specimen, is another key parameter.
The rate of displacement is also carefully monitored to ensure consistent testing conditions.
Types of Data Collected
Various data points are collected during the direct shear test, including but not limited to: shear stress, normal stress, shear displacement, and time. These values are recorded at regular intervals, typically at pre-determined points, throughout the test. Data logging systems record this information to ensure a complete and detailed record. The recorded data forms the basis for subsequent analysis.
Analysis Methods
The gathered data undergoes a meticulous analysis process to extract meaningful information. Typical analysis methods include plotting shear stress versus shear displacement curves. This visual representation allows for identification of key features such as peak shear strength, post-peak behavior, and the presence of any unusual characteristics. Furthermore, calculation of shear strength parameters like cohesion and friction angle is performed using the Mohr-Coulomb failure criterion.
This enables a deeper understanding of the material’s shear strength characteristics under different stress conditions.
Typical Data Recorded
| Parameter | Units | Description |
|---|---|---|
| Normal Stress | kPa (or psi) | Stress applied perpendicular to the shear plane. |
| Shear Stress | kPa (or psi) | Stress applied tangentially to the shear plane. |
| Shear Displacement | mm (or in) | Relative movement between the two halves of the specimen. |
| Time | seconds | Time elapsed during the test. |
| Load | N (or lb) | Force applied to the specimen. |
The table above illustrates a typical dataset that would be recorded during a direct shear test. Each parameter provides valuable insights into the material’s behavior under stress. Data analysis allows for a comprehensive understanding of the material’s shear strength characteristics, making it a valuable tool in geotechnical engineering.
Applications and Applications Examples
Unveiling the diverse world of direct shear testing, this section explores its practical applications across various fields. From understanding soil behavior to evaluating material strength, the direct shear test proves invaluable in design and construction. Its versatility makes it a go-to tool for a wide range of projects.Direct shear testing is more than just a laboratory procedure; it’s a powerful tool for predicting and understanding material behavior under shear stress.
By meticulously analyzing the results, engineers and scientists can gain insights into the performance of various materials and structures, ultimately leading to safer and more efficient designs. This crucial understanding is vital in the construction industry, where the stability and durability of structures are paramount.
Geotechnical Engineering Applications
Direct shear testing plays a critical role in understanding the shear strength of soil. It’s a cornerstone of geotechnical design, allowing engineers to assess the stability of slopes, retaining walls, and foundations. The results inform the design of various earthworks and excavations, ensuring stability and safety.
- Slope Stability Analysis: Direct shear tests determine the shear strength parameters of soil, enabling engineers to assess the stability of slopes under various loading conditions. Understanding how soil behaves under stress is crucial to predicting potential landslides or failures.
- Foundation Design: Direct shear testing provides critical data for the design of foundations. The shear strength of the soil supporting the foundation directly influences its bearing capacity and stability. Properly assessing this strength is essential to ensure the foundation can withstand the expected loads.
- Retaining Wall Design: Direct shear tests are fundamental in designing retaining walls. The shear strength of the soil behind the wall is a primary factor in determining the wall’s stability and preventing soil movement.
Civil Engineering Applications
Beyond geotechnical applications, direct shear testing finds widespread use in civil engineering. It’s crucial for evaluating the performance of various materials used in construction, including concrete, asphalt, and composite materials.
- Highway Design: Direct shear tests are used to assess the shear strength of asphalt layers. This data informs the design of road surfaces, enabling engineers to create durable and stable pavements that can withstand heavy traffic loads.
- Concrete Structures: Direct shear testing can evaluate the shear strength of concrete in structural elements like beams and columns. This ensures that these elements can safely resist applied forces.
- Composite Materials: The testing procedure extends to composite materials, allowing engineers to determine the shear strength of layered materials commonly used in modern construction.
Materials Science Applications, Direct shear test machine
The versatility of direct shear testing isn’t limited to the aforementioned fields. In materials science, it helps in determining the shear strength of various materials, including polymers, metals, and composites.
- Polymer Testing: Understanding the shear strength of polymers is crucial for designing products like pipes, films, and coatings. Direct shear tests provide the necessary data for these applications.
- Metal Testing: The test is also employed to assess the shear strength of metals in different applications. This data informs the design of metal components that need to resist shear forces.
- Composite Material Evaluation: Direct shear testing can help evaluate the performance of composite materials in various engineering applications.
Table of Applications and Use Cases
| Application Area | Use Cases |
|---|---|
| Geotechnical Engineering | Slope stability, foundation design, retaining wall design |
| Civil Engineering | Highway design, concrete structures, composite materials |
| Materials Science | Polymer testing, metal testing, composite material evaluation |
Safety Considerations
Operating a direct shear test machine safely is paramount. Proper precautions and adherence to established procedures minimize risks and ensure a productive and secure work environment. Understanding potential hazards and implementing preventative measures are crucial for personnel safety and equipment longevity.A meticulous approach to safety, encompassing pre-operational checks, controlled procedures, and emergency protocols, is essential when handling this machinery.
Thorough knowledge of the machine’s components, potential failure points, and appropriate response mechanisms is vital.
Pre-Operational Checks
A comprehensive pre-operational check minimizes potential hazards and guarantees the machine’s operational readiness. This involves verifying the machine’s structural integrity, ensuring all safety mechanisms are functional, and confirming the availability of necessary safety equipment.
- Visually inspect the machine for any signs of damage or wear.
- Verify the proper functioning of safety interlocks, such as emergency stops and pressure relief valves.
- Confirm the adequacy of the machine’s foundation and stability.
- Check the hydraulic fluid level and condition to prevent potential leaks and failures.
- Ensure proper grounding of the machine to avoid electrical hazards.
Operating Procedures
Adherence to proper operating procedures is critical for minimizing risks and ensuring a controlled environment. These procedures should be clear, concise, and easily understandable for all personnel involved in the testing process.
- Only authorized personnel should operate the machine.
- Ensure the test area is clear of obstructions and personnel.
- Verify the correct setup of the specimen and loading platens.
- Use appropriate personal protective equipment (PPE), such as safety glasses and gloves.
- Initiate loading procedures slowly and steadily, monitoring the machine’s performance and any unusual occurrences.
Potential Hazards
Understanding potential hazards allows for proactive risk mitigation. Knowing the risks associated with equipment failure, improper operation, and environmental factors is essential for preventing accidents.
- Equipment malfunction, such as hydraulic leaks or component failure, can cause injuries and damage.
- Improper specimen handling can lead to material ejection or uncontrolled movement, resulting in injury.
- Environmental factors, like inadequate ventilation or the presence of dust, can create a hazardous environment.
- Incorrect operation procedures, such as rapid loading or exceeding the machine’s capacity, increase the risk of accidents.
Emergency Response Procedures
Establishing a clear emergency response plan is crucial. This plan should Artikel procedures for handling various potential emergencies, such as equipment malfunctions or personnel injuries.
- Know the location of emergency shut-off switches and safety equipment.
- Report any malfunction or safety concern immediately.
- Have a trained individual available to handle potential emergencies.
- Follow established procedures for evacuating the area in case of a significant incident.
- Understand the specific emergency response procedures Artikeld in the facility’s safety manual.
Handling Equipment and Procedures
A step-by-step procedure ensures consistent and safe operation.
- Review the safety manual before operating the machine.
- Inspect all components and equipment for any signs of damage.
- Secure the specimen in the testing apparatus according to the manufacturer’s guidelines.
- Slowly and steadily apply the load, observing the machine’s indicators.
- Document the test parameters and observations accurately.
- Release the load safely and securely.
- Perform a post-operational check of the machine.
Maintenance and Calibration
Keeping your direct shear test machine in tip-top shape is crucial for consistent and reliable results. Proper maintenance and regular calibration are not just good practice; they are essential for ensuring the accuracy and longevity of your equipment. Imagine a finely tuned instrument, capable of revealing the secrets of soil behavior, constantly needing repair. This wouldn’t be ideal, would it?
This section will provide you with the tools to keep your machine humming along.
Routine Maintenance Procedures
Maintaining a direct shear test machine involves a multifaceted approach, from basic checks to more involved inspections. Consistent care is vital to prevent costly repairs and ensure the machine performs as expected. Ignoring maintenance can lead to malfunctions and potentially inaccurate data, undermining the entire testing process. This means that your results will not only be unreliable, but also potentially misleading.
- Visual Inspection: Regularly inspect all components for wear, damage, or unusual signs of stress. Look for loose bolts, bent levers, or any other irregularities. This preventative measure can prevent minor issues from escalating into major problems.
- Lubrication: Lubricate moving parts as per the manufacturer’s recommendations. Proper lubrication reduces friction and wear, extending the machine’s lifespan and improving performance. Think of it as keeping the machine’s engine running smoothly, ensuring consistent and efficient operation.
- Cleaning: Clean the machine regularly, removing dust and debris from all components. This helps prevent corrosion and ensures optimal functionality. Keep the machine clean to avoid unexpected breakdowns and maximize its life span.
- Record Keeping: Maintain detailed records of all maintenance activities, including dates, tasks performed, and any observations. This detailed record-keeping will allow you to trace the history of the machine and anticipate potential issues.
Calibration Importance
Regular calibration is essential for the accuracy of direct shear test results. This involves verifying that the machine’s measurements are accurate and consistent over time. Inaccurate measurements can lead to faulty conclusions and potentially misguide your decision-making. Calibration ensures that your data is reliable and can be used with confidence.
- Accuracy Validation: Calibration verifies that the machine’s readings accurately reflect the actual forces and displacements applied. Calibration ensures your measurements are correct and consistent, enabling you to make reliable decisions.
- Consistency Assurance: Calibration helps to ensure consistent results over time. A well-calibrated machine provides repeatable data, crucial for scientific accuracy and analysis. It allows you to trust the results you’re getting.
- Compliance Verification: Calibration can be required to meet industry standards or regulatory requirements. Compliance is crucial to avoid potential penalties or legal issues.
Common Maintenance Issues and Solutions
Recognizing and addressing common maintenance issues promptly can prevent major problems. Addressing these issues promptly can prevent costly repairs down the line. Addressing them quickly can help to save time and money.
- Loose Connections: Tighten loose bolts and connections to prevent slippage and ensure proper alignment. This ensures that all the parts work together as intended.
- Lubrication Problems: Ensure the correct type and amount of lubricant are used. Use the recommended lubricant to maintain optimal functionality and reduce wear and tear.
- Electrical Malfunctions: Address electrical issues promptly to prevent further damage. Check for loose wires, damaged connections, and any other potential electrical problems.
Calibration Procedures
Calibration procedures vary depending on the specific components of the machine. These procedures are crucial for ensuring the machine’s performance and accuracy. A well-calibrated machine is an essential tool for achieving accurate results.
- Load Cell Calibration: Use calibrated weights to verify the accuracy of the load cell readings. This ensures the machine accurately measures the applied loads.
- Displacement Transducer Calibration: Use known displacements to verify the accuracy of the displacement transducer readings. This ensures the machine accurately measures the movement.
- Hydraulic System Calibration: Verify the hydraulic system’s pressure readings using a calibrated pressure gauge. This ensures the machine applies the correct pressure.
Extending Equipment Lifespan
Implementing preventative maintenance measures can significantly extend the lifespan of your direct shear test machine. By taking care of your machine, you can avoid expensive repairs and maintain its high performance for many years.
- Regular Maintenance Schedule: Establish a regular maintenance schedule and adhere to it strictly. This is key to avoiding costly repairs down the line.
- Proper Storage: Store the machine in a clean and dry environment to prevent corrosion and damage. Proper storage is crucial to avoid issues caused by the environment.
- Proper Handling: Handle the machine carefully to avoid any damage to its components. Careful handling is essential to prevent unexpected malfunctions.
Illustrative Examples of Direct Shear Test Results
Unveiling the secrets of soil behavior, direct shear tests reveal critical insights into how different soil types react under stress. These tests, often used in geotechnical engineering, provide valuable data for designing stable and resilient structures. Understanding the patterns in the stress-strain curves allows engineers to predict soil behavior and make informed decisions.
Typical Shear Stress-Strain Curves
The stress-strain curves from direct shear tests offer a wealth of information about soil properties. These curves, plotted with shear stress on the y-axis and shear strain on the x-axis, show how the soil resists applied shear forces. The shape of the curve varies depending on the soil type, reflecting its internal friction and cohesion.
Sand
A typical stress-strain curve for a direct shear test on sand showcases a gradual increase in shear stress as shear strain increases. The curve exhibits a distinct peak, representing the maximum shear strength the sand can withstand before it starts to deform more readily. After the peak, the curve descends, demonstrating the residual shear strength of the sand.
The strain at failure is the point at which the shear stress drops significantly. This gradual degradation in shear strength is a hallmark of cohesionless soils.
Clay
Clay soils, unlike sand, exhibit a different behavior. Their stress-strain curve shows a more gradual increase in shear stress, reaching a peak strength at a relatively lower strain level compared to sand. The curve may show a significant post-peak strength, reflecting the soil’s ability to deform under continued stress. The strain at failure is often higher in clay soils than in sand, reflecting the greater plasticity of the soil.
Silty Sand
A silty sand exhibits a curve that combines characteristics of both sand and clay. The initial portion of the curve mirrors the behavior of sand, showing a peak strength. However, the post-peak behavior might display a more gradual decrease in shear stress, which is a significant difference from the sharp drop seen in purely sandy soils. The strain at failure depends on the relative proportions of sand and silt in the soil.
Table of Soil Types and Shear Strength
| Soil Type | Typical Shear Strength Characteristics |
|---|---|
| Sand | High internal friction, low cohesion, distinct peak strength, significant residual strength, relatively low strain at failure. |
| Clay | Low internal friction, high cohesion, gradual increase in shear stress, significant post-peak strength, relatively high strain at failure. |
| Silty Sand | Intermediate internal friction, intermediate cohesion, gradual increase in shear stress, intermediate residual strength, intermediate strain at failure. |
Understanding the Curves: A Deeper Dive
The curves visually depict the soil’s resistance to shear stress as it deforms. The peak strength represents the maximum shear stress the soil can withstand before failure. The residual strength is the shear stress the soil sustains after the peak is reached, providing valuable information about the soil’s stability under sustained loading. The strain at failure signifies the level of deformation experienced by the soil when it reaches its ultimate shear strength.
These parameters are crucial for geotechnical engineers in predicting soil behavior and designing structures accordingly.
