Measuring 3D indoor air velocity via an inexpensive low-power ultrasonic anemometer

The ability to inexpensively monitor indoor air speed and direction on a continuous basis would transform the control of environmental quality and energy use in buildings. Air motion transports energy, ventilation air, and pollutants around building interiors and their occupants, and measured feedback about it could be used in numerous ways to improve building operation. However indoor air movement is rarely monitored because of the expense and fragility of sensors. This paper describes a unique anemometer developed by the authors, that measures 3-dimensional air velocity for indoor environmental applications, leveraging new microelectromechanical systems (MEMS) technology for ultrasonic range-finding. The anemometer uses a tetrahedral arrangement of four transceivers, the smallest number able to capture a 3-dimensional flow, that provides greater measurement redundancy than in existing anemometry. We describe the theory, hardware, and software of the anemometer, including algorithms that detect and eliminate shielding errors caused by the wakes from anemometer support struts. The anemometer has a resolution and starting threshold of 0.01 m/s, an absolute air speed error of 0.05 m/s at a given orientation with minimal filtering, 3.1° angle- and 0.11 m/s velocity errors over 360° azimuthal rotation, and 3.5° angle- and 0.07 m/s velocity errors over 135° vertical declination. It includes radio connection to internet and is able to operate standalone for multiple years on a standard battery. The anemometer also measures temperature and has a compass and tilt sensor so that flow direction is globally referenced regardless of anemometer orientation. The retail cost of parts is $100 USD, and all parts snap together for ease of assembly

Right and left-sided infective endocarditis in an IV drug abuser

Infective endocarditis (IE) involving multiple cardiac valves is uncommon and has more risk of complications. We present an interesting case of infective endocarditis involving both aortic and tricuspid valves, suspected based on clinical presentation. He is a 54-year-old male with history of intravenous drug abuse (IVDA) who presented with exertional dyspnea, fevers/chills, fatigue, and temporarily vision loss. On exam, he had a low-grade fever, systolic murmur, bilateral crackles in lungs, and left hemineglect. He had leukocytosis and elevated BNP. First EKG showed first-degree AV block. CT head showed a subacute stroke in the right posterior cerebral artery (PCA) distribution. Transthoracic echocardiogram revealed a large tricuspid valve vegetation. He developed a second-degree heart block and a transcutaneous pacemaker was placed. Due to high concern for aortic valve involvement, a transesophageal echocardiogram was done revealing a large mobile tricuspid valve vegetation and an aortic valve ring abscess. He underwent abscess debridement and replacement of the aortic and tricuspid valve. He was found to have a ventricular septal defect which was also repaired. He recently had antibiotics for presumed pneumonia that is likely the reason for negative cultures. He received an 8-week course of Ceftriaxone for culture negative infective endocarditis and subsequently recovered well. This case report highlights that, although rare, the presence of right and left sided IE is possible and suspicion of aortic valve involvement is crucial in the setting of AV nodal blocks and peripheral embolic events. In patients with progressive heart blocks, transvenous pacemaker placement and valve replacement should be considered immediately to prevent further morbidity and mortality

Pure red cell aplasia and seronegative myasthenia gravis in association with thymoma

Pure red cell aplasia is an uncommon paraneoplastic syndrome of thymoma. Myasthenia gravis is the most common paraneoplastic syndrome associated with thymoma. We present a case of a 79-year-old Pacific Islander female who presented with profound fatigue, generalized weakness, significant unintentional weight loss, bilateral ptosis, and anemia. The bone marrow biopsy showed near absence of erythroid elements consistent with pure red cell aplasia. Ice-pack test was consistent with myasthenia gravis and computed tomography of the chest demonstrated a thymoma. The patient was started on immunosuppressive treatment with prednisone and cyclosporine. This case demonstrates a rare combination of paraneoplastic manifestations of thymoma: pure red cell aplasia and myasthenia gravis

Construction of the Control System of Cleaning Robots with Vision Guidance

The study uses Kinect, modern and depth detectable photography equipment to detect objects on the ground and above the ground. The data collected is used to construct a model on ground level, that is, used lead automatic guiding vehicle. The core of the vehicle uses a PIC18F4520 microchip. Bluetooth wireless communication is adopted for remote connection to a computer, which is used to control the vehicles remotely. Operators send movement command to automatic guiding vehicle through computer. Once the destination point is identified, the vehicle lead is forward. The guiding process will map out a path that directs the vehicle to the destination and void any obstacles. The study is based on existing cleaning robots that are available. Aside from fixed point movement, through data analysis, the system is also capable of identifying objects that are not supposed to appear on the ground, such as aluminum cans. By configuring the destination to aluminum cans, the automatic guiding vehicle will lead to a can and pick it up. Such action is the realization of cleaning function

Infrared-Fused Vision-Based Thermoregulation Performance Estimation for Personal Thermal Comfort-Driven HVAC System Controls

Thermal comfort is one of the primary factors influencing occupant health, well-being, and productivity in buildings. Existing thermal comfort systems require occupants to frequently communicate their comfort vote via a survey which is impractical as a long-term solution. Here, we present a novel thermal infrared-fused computer vision sensing method to capture thermoregulation performance in a non-intrusive and non-invasive manner. In this method, we align thermal and visible images, detect facial segments (i.e., nose, eyes, face boundary), and accordingly read the temperatures from the appropriate coordinates in the thermal image. We focus on the human face since it is often clearly visible to cameras and is not merged into a hot background (unlike hands). We use a regularized Gaussian Mixture model to track the thermoregulation changes over time and apply a heuristic algorithm to extract hot and cold indices. We present a personalized and a generalized comfort modeling method, selected based on the availability of the occupant historical indices measurements in a neutral environment, and use the time-series of the hot and cold indices to define corrections to HVAC system operations in the form of setpoint constraints. To evaluate the efficacy of our proposed approach in responding to thermal stimuli, we designed a series of controlled experiments to simulate exposure to cold and hot environments. While applying personalized modeling showed an acceptable average accuracy of 91.3%, the generalized model’s average accuracy was only 65.2%. This shows the importance of having access to physiological records in modeling and assessing comfort. We also found that individual differences should be considered in selecting the cooling and heating rates when some knowledge of the occupant’s overall thermal preference is available

Measuring 3D indoor air velocity via an inexpensive low-power ultrasonic anemometer

The ability to inexpensively monitor indoor air speed and direction on a continuous basis would transform the control of environmental quality and energy use in buildings. Air motion transports energy, ventilation air, and pollutants around building interiors and their occupants, and measured feedback about it could be used in numerous ways to improve building operation. However indoor air movement is rarely monitored because of the expense and fragility of sensors. This paper describes a unique anemometer developed by the authors, that measures 3-dimensional air velocity for indoor environmental applications, leveraging new microelectromechanical systems (MEMS) technology for ultrasonic range-finding. The anemometer uses a tetrahedral arrangement of four transceivers, the smallest number able to capture a 3-dimensional flow, that provides greater measurement redundancy than in existing anemometry. We describe the theory, hardware, and software of the anemometer, including algorithms that detect and eliminate shielding errors caused by the wakes from anemometer support struts. The anemometer has a resolution and starting threshold of 0.01 m/s, an absolute air speed error of 0.05 m/s at a given orientation with minimal filtering, 3.1° angle- and 0.11 m/s velocity errors over 360° azimuthal rotation, and 3.5° angle- and 0.07 m/s velocity errors over 135° vertical declination. It includes radio connection to internet and is able to operate standalone for multiple years on a standard battery. The anemometer also measures temperature and has a compass and tilt sensor so that flow direction is globally referenced regardless of anemometer orientation. The retail cost of parts is $100 USD, and all parts snap together for ease of assembly