How to build an aquaponics system step by step pdf. keep up with the build progress here.
How to build an aquaponics system step by step pdf (1978), it used complex I want to show you how to build an aquaponics system step by step. Building your own aquaponics system is a fun and rewarding project, and it’s not as difficult as you might think! Keep reading for detailed instructions on how to build an aquaponics system. Choose a location for your aquaponics system that gets plenty of sunlight and has a flat, level surface. Jul 19, 2023 · The Benefits of Building Your Own Aquaponics System. Whether starting small or investing in a large setup, you’ll find helpful advice for sustaining a productive aquaponics garden that serves up Chapter 7: Troubleshooting Common Problems: Identifying and Solving Issues in Your Aquaponics System. It integrates hydroponics Jun 29, 2024 · Benefits of Having a DIY Aquaponics System. Plus, there’s a video to walk you through each step of the building process. We designed this workbook as a step-by-step guide to help people who are interested in setting up their own aquaponics system in the backyard. Also included is a step by step gu. Chapter 7: Troubleshooting Common Problems: Identifying and Solving Issues in Your Aquaponics System. uky. This system houses approximately 100 gallons of water that is continuously cycling throughout. Setting up an aquaponics system can be an enriching and sustainable way to grow your own vegetables and rear fish with minimal environmental impact. Get an overview of the design features and functions of each system; Learn how to build your own aquaponic system - from easy to more advanced set-ups; Learn about the supplies you need for each system Feb 10, 2022 · The first step is to have a water source, the second step is to have a filter, and the third step is to have an outlet for the filtered water. If you preferred. Aug 28, 2022 · Request PDF | Aquaponics for Beginners A step by step complete guide for beginners on how to build their Aquaponics | آکواپونیک ترکیبی از فناوری تولید مواد Following are instructions for building a small system that is ideal for a teacher, students or hobbyists who want to get a start in aquaponics. The fish or other aquatic animals you raise provide waste materials which are filtered into the hydroponic environment to be used as fertilizer. ---# Aquaponics Mastery: A Step-by-Step Guide Oct 23, 2024 · This factsheet is a step-by-step guide to building a small aquaponics system using repurposed Intermediate Bulk Container (IBC) and parts easily found online or at Chapter 7: Troubleshooting Common Problems: Identifying and Solving Issues in Your Aquaponics System. How To Build An Aquaponics System Step By Step Pdf The Aquaponic Farmer Adrian Southern,Whelm King,2017-09-01 Profitable cold water fish and vegetable production Join the aquaponic farming revolution Built around a proven 120 greenhouse system operable by one person The Aquaponic Mar 6, 2024 · The plumbing for the aquaponics system is not too complicated and you can rely on a few basic principles to help make the system as efficient as possible. I want to show you how to build an aquaponics system step by step. For a step-by-step guide, you can view this video (u-siphon in grow bed). How To Build An Aquaponics System Cheap (Step By Step) Although every aquaponics system will be a bit different, there are a few key components that you will need to include no matter what. Once you’ve got the system up and running you can grow virtually anything in your vertical aquaponics system; all you have to do is be prepared to try! In this video step by step how to make Aquaponics system at home, and how to make your own grow beds with siphon and filter, fish tank and the best option f Jan 7, 2022 · Types Of Aquaponics Systems. Jan 23, 2022 · From this, he goes on to explain how growers can build a total of 12 different systems using around-the-house materials. Freshwater, herbivorous or omnivorous fish are ideal choices for their sustainability, ease of feeding, and efficient conversion of feed. There are several types of aquaponics systems to choose from, depending on your budget and requirements. … Solid fish waste is turned into vermicompost that also acts as food for the plants. DIY aquaponics in five easy steps. Jan 25, 2024 · Regular monitoring of water parameters such as pH, ammonia, nitrite, and nitrate levels is essential to keep your aquaponics system in balance. This step-by-step guide describes how to build the media bed, nutrient film technique (NFT) and deep water culture (DWC) systems for the small-scale aquaponic units described in Chapter 4 of this publication. Dec 15, 2024 · Water quality is the cornerstone of a thriving aquaponics system, as it directly impacts both fish and plant health. Oct 8, 2023 · Understanding Aquaponics. This type of system floods the grow bed, and then drains through a siphon providing nutrient rich water and oxygen for the roots. Step 3 – Cutting the Barrels Step 4 – Creating the Cuts for Pipework Step 5 – Final Cutting for a Duckweed Tank Step 6 – The Piping System Chapter 8- Operating your System Chapter 9- Frequently Asked Questions Chapter 10- Aquaponics Produce Chapter 11- Native Aquatics and Foreign Aquatics Chapter 12- Staying in Balance Apr 13, 2021 · #Aquaponic_System#RAS_systemCombining plants and fish in a RAS is referred to as aquaponics. Harvesting the produce from your aquaponics system is an exciting and rewarding experience. Dec 29, 2024 · Media Bed Aquaponics System Deep Water Culture (DWC) The deep water culture is also known as the raft system or the floating system. There are several benefits to using an aquaponics system for growing plants and raising fish. With the help of DIY Aquaponics System, you’ll be able to learn everything you need to know about placing the floats, choosing the right material, and planting your seedlings in the eBook. To build your own aquaponic system, you’ll find step-by-step instructions, diagrams, and explanations in this eBook. This kind of system is ideal to grow leafy greens. Oct 31, 2023 · Risk management systems Aquaponics systems are commonly in vicinity of humans and that can be a serious concern for public health. Before you plan to build a small aquaponics system, you shall consider the follow questions, by which you will get a primary designning idea on your own small aquaponics system diy. Large, ready-made aquaponics systems can be expensive to buy. How to Build an Aquaponics System – Step by Step. Cycling your aquaponics system is a crucial step in preparing it for fish and plant cultivation. Although I’ve already covered how to actually design and construct one (including all the parts) in a step by step manner in the DIY Aquaponics article, I’ll write the outline here. Building a aquaponics framework can be straightforward or complex, contingent upon your financial plan and your requirements. Step 1: Selecting the Right Location. Complete supply list and what tools are required. Jun 30, 2020 · This is possibly the easiest and common aquaponics system for sale because it is most preferred for home growers and the one that we’ll be focusing on in this article to guide how to build an aquaponics system step by step. This aquaponics system is excellent for beginners who want to start small and save on start-up costs. As long as you use the recommended 100 gallon fish tank, you will be able to add on as much as three more 2’x4’ grow beds later on for a total of four beds. Feb 21, 2024 · To make an aquaponics system step by step, you need to carefully plan water filtration, plant selection, nutrient cycling, system maintenance, fish stocking, grow bed setup, pH balance, water testing, lighting requirements, and pest control for optimal results. Build an Aquaponics system Step 1: Build Your Media Bed Jun 9, 2024 · Imagine having a self-sustaining ecosystem right on your desk, where fish and plants thrive together in harmony. So instead, follow these simple steps. In chapter 4, this book will scrutinize the relevance of How To Build An Aquaponics System Step By Jun 12, 2022 · This video is the beginning of a new series of videos showing you step by step how to build an Aquaponics System out of IBC totes. Conclusion. sustainable food as inexpensively as possible If yes then keep reading In Aquaponics Joseph Bosner eliminates the guesswork and lays out everything you need to know of building your aquaponics system first before you move on to building an advanced system. In an aquaponics system, fish are raised in a tank or pond, and their waste is converted into nutrients for plants grown in a separate bed. Choose a suitable location for your aquaponics setup. edu In 1986, Zweig developed a simple and productive aquaponic system by matching the feeding rate and biomass of the fish to the estimated nitrogen needs of the plants. Aquaponics is becoming more popular by hobbyists who make their DIY systems with IBC totes. Creating a DIY aquaponics system from scratch requires planning and takes time. 2 is ideal for most aquaponics systems. Iron deficiency was addressed by replacing 20% of the fish feed with rabbit feed. Its compact size makes it ideal for apartments and other small spaces. See full list on aquaculture. Before diving into greenhouse design specifics, let’s briefly understand what aquaponics is. 2 to support optimal nutrient availability for plants. For some helpful tips and tricks before you start, watch part 13 How to Build an Aquaponics System Step by Step. ---# Aquaponics Mastery: A Step-by-Step Guide Chapter 7: Troubleshooting Common Problems: Identifying and Solving Issues in Your Aquaponics System. The most simple definition of Aquaponics is the combination of aquaculture (raising fish) and hydroponics (the soil-less growing of plants) that grows fish and plants together in one integrated system. Of course, some setups require fewer supplies and materials than others. 1 Use a small 600 lph (litres per hour) electric submersible pump in one corner of the fish tank which takes the water up to the growbed. Here we have provided you with different information quelle, so that you can go press search for more information yourself. Food safety begins on the farm or in this case, in aquaponic systems. Here’s how to set up an aquaponics system that will allow you to grow your own food at home using the media bed system. Follow along with Dr. In this type of system ammonia produced by the fish is not only 2. Getting the maximum amount of veggies growing in your small space. A vertical aquaponic system grows vegetables without soil in columns above a fish tank. Our aquaponics system can be constructed using whatever materials you have All aquaponics systems have certain common components, that are tied together by the science of recirculating water. Building an aquaponics system step by step is a more straightforward process than you might think. Dec 6, 2019 · Set up your own aquaponic system with easy to apply step-by-step instructions and save money by using inexpensive building methods. A pH between 6. The most common types of aquaponics systems are: Media-Based Aquaponics System; Deep Water Culture (DWC Jul 23, 2023 · If you’re a farmer looking to explore aquaponics, this step-by-step guide will provide you with the knowledge and guidance you need to build your own system. follow along as i build my system! i'm documenting the process to make it easy for you! build an aquaponic systemthis is just the beginning!!!welcome to aquaponic system diy!my name is jeff continue reading. With over 300 photos for your reference. Water Filters. Make sure your aquaponics U siphon leaves some space between the loop and top of the grow bed. With a mini desktop aquaponics system, you can enjoy Mar 1, 2021 · PDF | Practical Handbook for Aquaponic Growers | Find, read and cite all the research you need on ResearchGate Oct 6, 2023 · 3. This can be done by unbolting the bars on the top and removing them; the tote should lift straight out. It can range from a few hundred dollars for a small, DIY setup to thousands of dollars for a larger, commercial system. Step one: Put your fish tank together. Following is a list of the parts you’ll need to build a mini aquaponic system. You can always add on and customize your system as needed or depending on your unique goals and circumstances. pdf. A basic bamboo bed can be constructed and look perfect. Check out the image below if you want to know more about items. The type of system you choose will depend on the size of the area available for setup and the number of fish and plants desired. Here’s a step-by-step guide to building your own aquaponics system: Step 1: Choose a Location. Theo Willis as he explains what materials you need, necessary modifications, and the process of setting this up from beginning to end. ca. How To Build An Aquaponics System Step By Step How to Build an Aquaponics System Step-by-Step: A Beginner's Guide Want to grow your own food while minimizing your environmental impact? Aquaponics, the symbiotic combination of aquaculture (raising fish) and hydroponics (growing plants without soil), might be the perfect solution. At its core, aquaponics is a system that combines aquaculture (the raising of fish) with hydroponics (the cultivation of plants in water). Just like keeping fish, you’ll need to take into account all the safe practices of fishkeeping. System Overview • This is a dual loop system with: – 2 100‐gallon fish tanks – a radial filter – a bio filter – two sump tanks – 2 water pumps – 2 air pumps with 8 airstones – 4 ftx 20 ftgrow bed. Conclusion Aug 2, 2022 · The cost of building an aquaponic system can vary greatly depending on the size and complexity of the system. There are three main aquaponics methods; the Media Based method, Nutrient Film Technique (NFT) and Deep Water Culture/Floating Raft Systems. I get this question often: What materials do you need for aquaponics? When building an aquaponics system, you need some supplies to get started. r aquaponics system (Know Before You Build). The water in the system is continuously recycled, reducing waste. Aquaponics is a sustainable method of food production that involves the symbiotic cultivation of plants and aquatic animals in a recirculating environment. The workbook was created to work as a guide for beginners by providing detailed explanations of how to design, build and maintain an aquaponics system. Brilliant Vertical Aquaponics System Mar 9, 2019 · I want to show you how to build an aquaponics system step by step. Jul 23, 2023 · Additionally, maintaining adequate nutrient levels and addressing any nutrient deficiencies promptly will contribute to the overall health and productivity of your plants in the aquaponic system. What is the point of aquaponics? A: Aquaponics is a method of farming that combines raising aquatic animals with growing plants in a symbiotic environment. The fish tank houses your fish, which provide the nutrients for the plants. The system involves three main components: fish tanks, grow beds, and a water pump. Jul 23, 2023 · Properly Cycling Your Aquaponics System to Avoid Fish Stress and Promote Plant Growth. Types of Aquaponics Systems. Things to consider before building your indoor aquaponics system: Jul 15, 2022 · In this post, we’ll show you how to build an aquaponics system step by step. keep up with the build progress here. Water is an essential component of an aquaponics system. Using less water to grow healthy, luscious veggies that you didn't think was possible. ---# Aquaponics Mastery: A Step-by-Step Guide Jul 24, 2020 · Step 2# Having a primary designning idea. Mar 28, 2024 · Key Components of an Aquaponic System. efficacious working Types of Aquaponics Systems Step by Step Guide to Start Aquaponic Gardening Best Plants for Your The first step in creating your IBC tote aquaponics set up is to remove the steel cage from round the tote. From the Fish Tank, Radial Learn how to build 2 different aquaponics systems. Building your own aquaponics system offers a multitude of benefits. Building your own aquaponics system offers numerous benefits: Sustainability: Aquaponics uses significantly less water than traditional gardening, making it an environmentally friendly choice. After you’ve planned your system, it can be tempting to buy everything at once and get started. To Build An Aquaponics System Step By Step can be effectively utilized in everyday scenarios. Having sufficient lighting is essential for your homemade aquaponics system. ---# Aquaponics Mastery: A Step-by-Step Guide important step in the development of the technology, it went largely unnoticed. 8 and 7. While this work was an important step in the development of the technology, it went largely unnoticed. Just moments from now you will be on your way to up to ten times the plants, growing amazing organic produce faster, healthier, without weeding or messing around with Mar 7, 2019 · I want to show you how to build an aquaponics system step by step. Jul 11, 2013 · Advantages of Aquaponic Farming. Understanding Aquaponics. Chapter 8: Advanced Aquaponics Techniques: Expanding Your System and Optimizing Production. (1985) developed a recirculating aquaponics system at the University of the Virgin Islands (UVI). This is a simple two-component aquaponic system, based on the utilization of an IKEA-style wire baskets. Benefits of Aquaponics. Harvesting and Using the Produce from Your Aquaponics System. Hydroponics farm is growing plants without soil, in this video I am showing you step by step how to make DIY homemade Hydroponics Grow Kit Planting Sites Gar The first aquaponics system that FoodChain ever built was a small demonstration system, using recycled 55 gallon barrels and locally available materials. Your A-Z, step-by-step blueprint to build and look after your own aquaponics system. Building an aquaponics system can seem daunting, but it’s not as complicated as it seems. We will guide you through the cycling process, discussing methods such as fishless cycling and fish-in cycling. The vertical aquaponics system is perfect for anyone just starting in aquaponics; especially if you have limited space available. Building an Aquaponics System. It’s easy and affordable to construct. Regular testing allows you to catch imbalances early and make necessary adjustments. Linked to this you will need to install a water pump and circulation system. Here is a step-by-step guide to building your aquaponic system. You could make a Do-It-Yourself water sanitization grower utilizing a piece of bamboo. A U siphon is a very helpful tool for anyone interested in aquaponics. Jan 8, 2024 · Keep reading this guide to discover step-by-step aquaponics instructions. 5. Firstly, it allows you to have full control over the inputs and ensure that your produce is grown organically. This guide supports 21st-century skills by engaging your students in learning the history of aquaponics through various texts, communicating how an aquaponics system works, and engineering your own classroom aquaponics sy. If you are looking for a complete kit, be sure to check out our Clear Flow Aquaponic Systems® What You’ll Need. At the heart of any aquaponic system are a few key components: the fish tank, the grow bed, a water pump, and a filtration system. Aquaponics systems rely on water to provide a steady stream of nutrients to the plants, as well as to clean and cool the fish and vegetable tanks. By growing vertically, you can produce about twice the amount of plants as you can with a hydroponic system of the same area. (Half-Barrel and IBC Totes) We provide you with a complete "Step by Step" instructional manual. Knowing what is on, or not on your food. ---# Aquaponics Mastery: A Step-by-Step Guide Nov 4, 2024 · The Setup Process for Aquaponics System. subscribe me! find it here. Ensure all components are in place, including the fish tank, grow beds, and water pumps. Water circulation system. You’ll get insider tips on choosing fish and crops, proper system sizing, and troubleshooting issues like pH fluctuations. Accessing How To Build An Aquaponics System Step By Step Pdf Free and Paid eBooks How To Build An Aquaponics System Step By Step Pdf Public Domain eBooks How To Build An Aquaponics System Step By Step Pdf eBook Subscription Services How To Build An Aquaponics System Step By Step Pdf Budget-Friendly Options 6. Set Up the System: Assemble your aquaponics system following the step-by-step instructions provided by Aquaponics 4 You™. These How To Build An Aquaponics System Step By Step Pdf The Aquaponic Farmer Adrian Southern,Whelm King,2017-09-01 Profitable cold water fish and vegetable production Join the aquaponic farming revolution Built around a proven 120 greenhouse system operable by one person The Aquaponic Nov 21, 2023 · Building Your Aquaponics System. 2) Step-by-Step Guide. Aquaponics is actually a new way of approaching farming. Mar 9, 2019 · I want to show you how to build an aquaponics system step by step. Now that you have a basic understanding of how aquaponics works, let’s move on to the practical steps of building your system. In 1985, Nair et al. ---# Aquaponics Mastery: A Step-by-Step Guide Apr 28, 2021 · Aquaponics 4 You™ - step-by-step how to build your own aquaponics system. Similar to the system of Lewis et al. The plants, in turn, filter the water for the fish, creating a closed-loop system. You may even want to build the single grow bed system first. Mar 18, 2020 · Aquaponics 4 You™ - step-by-step how to build your own aquaponics system. Q: Can I use any type of fish in my Chapter 7: Troubleshooting Common Problems: Identifying and Solving Issues in Your Aquaponics System. The beauty of this system lies in the symbiotic relationship between the fish and the sustainable food as inexpensively as possible If yes then keep reading In Aquaponics Joseph Bosner eliminates the guesswork and lays out everything you need to know Remember the height of the loop determines the maximum height of the water level. How To Build An Aquaponics System Step By Step Aquaponics for Beginners Nick Brooke,2018-11-28 Aquaponic gardening is a great method for raising fish and vegetables together Aquaponic farming is a sustainable and commercially profitable way of organic farming The waste of the Mar 11, 2021 · Bamboo is an incredible material for funneling and a channel for water. This DIY approach gives growers the chance to learn about Hydroponics as they build one of the simple systems, he also explains the components and how they affect the running of the system, and how plants will be affected by 5. de to set up a system as a teacher resource. ---# Aquaponics Mastery: A Step-by-Step Guide If you have a tank you could fill with water and fish (such as a stock tank) and a few pieces of PVC pipe; you could easily have a PVC gravity fed aquaponics system. This step-by-step guide with photos explains the process of making the single-barrel aquaponics system. Our aquaponics system can be constructed using whatever materials you have Ebb and Flow (Flood and Drain) - This is the type of aquaponics system I will be using in this instructable. Easy IKEA-hack Indoor Aquaponics System by Japan Aquaponics. The aim of anyone who plans to setup a DIY aquaponics system is to mimic this ecosystem, by creating a separate space for both the aquaculture and the hydroponics, and then connecting them. Make sure to bring the system online slowly in a step-by-step fashion. A wide variety of fish and other aquatic animals can be farmed in aquaponic systems. The first aquaponics system that FoodChain ever built was a small demonstration system, using recycled 55 gallon barrels and locally available materials. . Mar 2, 2020 · It’s actually one of this written leaders extra video training prog, and aforementioned thing shows you exactly how to build at aquaponics system step by step. Understanding the Basics of Aquaponics Before diving into the details, it’s important to grasp the basic concepts of aquaponics. Feb 9, 2024 · How To Build An Aquaponics System. In this type of system, rafts made of polystyrene or foam board float on top of the nutrient-rich water as it circulates through the lengthy canals at a depth of typically 7 to 8 inches. The smaller, upper basket is used for housing plants, and the lower, deeper one for housing the fish. 10. But that’s a recipe for disaster. This is aquaponics, a gardening method that combines aquaculture (raising fish) and hydroponics (growing plants without soil) in a symbiotic environment. Whether you’re setting up a small indoor unit or scaling up for commercial production, understanding these components and the roles they play is crucial. Although there are smaller kits available, building a DIY aquaponics system can be extremely rewarding. Feb 14, 2024 · Various types of aquaponics systems, including the Nutrient Film Technique, Raft System, and Media Based System, offer flexibility to adapt to your space and budget constraints. How to Build an Aquaponics System Step By Step at Home (PDF)Aquaponics is one of the most eco-friendly methods for producing food. Start Your Vertical Aquaponics System Today. Mar 8, 2019 · I want to show you how to build an aquaponics system step by step. Just moments from now you will be on your way to up to ten times the plants, growing amazing organic produce faster, healthier, without weeding or messing around with Apr 25, 2019 · I want to show you how to build an aquaponics system step by step. Conclusion: Reaping the Rewards of Your Homegrown Aquaponics System. Aquaponics 4 You comes jam-packed with all the step-by-step instructions, secrets and common mistakes. Additionally, aquaponics systems require significantly less water compared to traditional soil-based gardening Finally, aquaponics systems can be set up anywhere, making them an ideal solution for urban farming. ---# Aquaponics Mastery: A Step-by-Step Guide Aug 5, 2023 · Q: How much time do I need to invest in maintaining an aquaponic system? Maintaining an aquaponic system requires regular attention, but once established, it’s relatively low maintenance. pH measures the acidity or alkalinity of the water and should ideally be maintained between 6. Yes, you will need to provide the right environment for your fish to thrive – but you also need to get the water (with the nitrates) to flow up to the roots and then back down again. Schematic drawings on various components. When exposed outside the house, the system faces potential risks from various harmful substances that can enter the tank, potentially causing damage to your aquaponics system. ---# Aquaponics Mastery: A Step-by-Step Guide Oct 9, 2019 · Aquaponics refers to any system that uses aquaculture and hydroponics in unison to create a mutually beneficial environment. Aquaculture: Building and Caring for a Miniature Aquaponics System – This PDF from the Iowa State University Extension and Outreach is a straightforward 7-page document covering the construction of a (very) small aquaponics system. Jul 18, 2018 · DOWNLOAD our Aqauponics E-Books TODAY! Our materials will walk you through the complete building process of two different systems along with a greenhouse. Let’s begin with the definition of an aquaponics system. Here are the top five fish we recommend: !Tilapia •! Ideal for large scale aquaponics systems •! Dec 16, 2024 · You will need a barrel, drill, and jigsaw to build this simple aquaponics system. Free DIY Aquaponics System PDFs Miniature Aquaponics System for Beginners. One five-foot tower can produce more than 200 heads of lettuce per year. In short Apr 18, 2022 · If you’re looking to build an aquaponics system yourself, make sure you buy a good water pump before you start construction. As opposed to traditional agriculture where you required plants to develop vegetables, with aquaponics you will need water and fish as a way to have healthy meals in your table every day. This article provides a brief explanation of the main components of this production method and a systematic guide to construct a small-scale Deep Water Culture (DWC) system at home. If you follow the instructions in Aquaponics 4 You and don't get the results we've talked about here with your plants: If you can't use the step-by-step plans and instrucitons inside to build your first amazing aquaponics system and get an amazing yield with your first plants These videos will take you through how to build an aquaponics system for your home, office, or school from start to finish. How To Build An Aquaponics System Step By Step consigli e ricette per il benessere di corpo e an - Oct 27 2021 web apr 24 2023 informazioni sui consulenti scientifici una guida completa sul rapporto tra alimentazione e benessere in questo articolo riporteremo informazioni utili su come Nov 20, 2023 · To ensure proper protection, it is important to cover your outdoor system adequately. This takes time to get everything up to speed. You’ll need to monitor water parameters and tend to the plants and fish, which may take around 1-2 hours per week. Parameters to Test: pH Levels: Fish and plants thrive within specific pH ranges. Each has it’s own pros and cons, NFT setups are more suitable for vertical farming whilst Media Based systems suit flat grow bed tanks, and DWC systems are suitable for either, but each provide growers with the option to setup in or outdoors, and to Dec 14, 2017 · TotePonicsVer4. Aquaponics systems come in a variety of shapes and sizes, allowing you to set up an aquaponic system that best fits your space and lifestyle. zjlwvvxwgaliivesxmcuioeseynyygaghrywgupqwlvfelramxuulakspnckfoubilkby