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Air pollution impacts
Published in Abhishek Tiwary, Ian Williams, Air Pollution, 2018
The respiratory system is by far the most important route for entry of air pollutants into the body. The basic structure is shown in Figure 10.9. When the ribs and/or diaphragm are expanded, the increased volume (and hence reduced pressure) in the chest draws air in through the nose or mouth. The nasopharyngeal region is the complex of larger passages in the nose, sinuses and upper throat through which the air passes before going into the throat (trachea). In the tracheobronchial region, the trachea divides into two bronchi, each of which leads to one of the two lungs. The bronchi then branch repeatedly into bronchioles before ending, in the pulmonary region, in clusters of tiny sacs called alveoles (Figure 10.10). There are around 300 million alveoles in the lungs, each having an inflated diameter of about 0.25 mm. The total area of these alveoles is 50–100 m2. The alveoles, where oxygen, water vapour and CO2 are exchanged, effectively present a very thin membrane of large surface area to the blood supply.
Occupational Health Hazards of Nanoparticles
Published in Chaudhery Mustansar Hussain, Gustavo Marques da Costa, Environmental, Ethical, and Economical Issues of Nanotechnology, 2022
Sandra Magali Heberle, Michele dos Santos, Gomes da Rosab
Chest: The lungs are located inside the chest. The ribs, which form the rib cage and make a framework protecting the lungs and heart, lean forward by the action of the intercostal muscle, causing an increase in the volume of the thoracic cavity. The volume of the chest also increases by contraction down the diaphragm muscles. When the thorax expands, during inspiration, the lungs begin to fill with air (Adamec et al. 2019 b).
Ergonomics
Published in Martin B., S.Z., of Industrial Hygiene, 2018
The musculoskeletal system consists of bones and muscles. Bones form the skeleton which protects organs and organ systems within the human body. The vertebrae protect the spinal column, the ribs protect the heart and lungs, and the pelvis protects the reproductive and abdominal organs. Bones also are used to support the weight of the human body. The bones of the legs and feet must be able to withstand the force of gravity and the constant pounding of walking, running, and lifting. In order for humans to achieve movement, these bones must be connected by contractual tissue. This tissue is known as muscle. Muscles consists of a number of fibers bundled together to form one mass. There are three types of muscles: voluntary, involuntary, and heart (cardiac muscle). Voluntary muscles are called skeletal or striated muscle and connect the bones of the body. Involuntary muscles are found in the internal organs and are known as smooth muscle. It is important to note that muscles can only pull. Therefore, any muscle must have a restretch mechanism. In cardiac muscle, the restretch mechanism is accomplished by new blood entering the chambers, smooth muscles are re-stretched when material enters the organ and skeletal muscles work in pairs so as one muscle contracts the other is stretched. This arrangement of skeletal muscle pairs is known as antagonistic (for example, biceps and triceps). Skeletal muscle bundles are connected to the bone by tendons. The end of the muscle attached to the more stationary joint is called its origin, while the attachment at the moving part is called its insertion. However, since humans are flexible, there must be one additional mechanism available which allows for movement. These articulations are called joints. The bone and joint form a lever system with the bone being the lever and the joint being the fulcrum. There are six types of body movements which can occur around joints (refer to Table 12.5).
Experimental investigation of heat transfer and pressure drop using combination of ribs and dimples
Published in Australian Journal of Mechanical Engineering, 2023
Prakash Santosh Patil, K. K. Dhande, S. L. Borse
In recent years, due to developments in technology, new ribs have been developed and presented by researchers. Singh, Ji, and Ekkad (2018) investigated numerically the criss-cross rib pattern and found improvement in heat transfer from 2.7 to 3.1. Wang et al. (2018) presented wavy ribs and concluded that rib parameters like height, radius and angle have big influence on heat transfer enhancement and also ribs with more height and massive round radius performed superior compared to other ribs. Xie et al. (2017) reported straight, concave and convex type’s crescent ribs and concluded that concave rib performed best. Dimples are used in cooling passage due to its advantages of low-pressure penalty, while the heat transfer enhancement is less than ribbed channels. Rao, Wana, and Xu (2012) studied experimentally the influence of dimple depth on thermal performance. Results indicated that pin fin-dimple channel with dimple depth to diameter ratio 0.1–0.2 reported relatively lower frictions with dimple depth to diameter ratio 0.3. Rao also presented different dimple shapes at Reynolds numbers 8500 to 60,000. They concluded that the teardrop dimples have 18% more heat transfer and elliptical dimples have less friction compared to spherical dimples (Rao et al. 2015). Also, Du et al. (2019) conducted numerical simulation for dimple locations and concluded that the dimple locations have marvellous effects on the flow structure and heat transfer in a dimpled pin finned channel. Ribs and dimples alone both have some advantages and disadvantages related to augmentation of heat transfer and pressure drop.
Effect of geometrical and mechanical parameters of ribs submitted to high velocity impact. A numerical investigation
Published in Mechanics of Advanced Materials and Structures, 2022
Thoracic injuries happen frequently in various frameworks of impact biomechanics such as automotive industries, sports and high-velocity ballistic impacts, second fatal injury behind head injury [1–5]. Rib fractures are common in thoracic injuries that can lead to life-threatening injuries, such as bone fragments of ribs perforating the lung pleural surface, lung parenchyma, liver or heart, which may result in pneumothorax, hemothorax or death [6, 7]. Specifically, the elderly who are more likely to encounter rib fractures, they need longer recovery time or even face higher mortality owe to the decreased thoracic injury tolerance [8, 9]. In consequence, it is of importance to investigate the dynamic responses of ribs under dynamic loadings, which can help understand the mechanisms of rib fractures and corresponding injury criterion.