Разработка и обоснование параметров емкостного датчика высева семян пропашных культур

Abstract. The development of a universal control system requires designing unified seed sowing sensors that allow controlling the sowing of seeds of different crops. (Research purpose) To provide theoretical grounds for the determination of parameters and installation location of a capacitive seeding sensor. (Materials and methods) In the course of the study, the authors have made theoretical calculations of the seed travel trajectories in mechanical and pneumatic sowing machines using the Mathcad and Microsoft Excel software systems, at various sowing machine frequencies: 11.5; 17.5 and 26.0 revolutions per minute as well as the calculation of the electrical parameters of the designed seeding sensor. Laboratory studies of the trajectory have been performed at the same rotational speeds of the sowing unit disc using high-speed seeding surveys on an experimental installation with subsequent processing of the obtained video materials. The optimum installation angle of the sensor has been experimentally studied from 0 to 67.5 degrees with a pace of 22.5 degrees to minimize the travel time of seeds through the sensitive area of the sensor, and as a result, to increase the sensor resolution using the developed software. (Results and discussion) Geometric and electrical parameters of the designed sowing sensor have been obtained, and its optimum location has been determined. (Conclusions) In the course of laboratory studies, data similar to the calculation results have been obtained; the relative value of the convergence coefficient between experimentally obtained and theoretical indicators does not exceed 0,55, provided these values are obtained at a distance less than the radius of seeds. The authors have experimentally determined the minimum distance between the sensor plates, which amounts to 20 millimetre, and calculated the electrical parameters of the sensor. They have also stated that the height of the sensitive zone should be at least 5 millimeters for reliable metering of individual seeds under these conditions. The obtained data allowed designing an experimental seeding sensor to determine the optimum angle and the sensor installation site. It has been concluded, that in order to minimize the travel time of seeds in the sensitive area of the sensor, the latter should be installed perpendicularly to the flight trajectory of the seeds.Реферат. Для создания универсальной системы контроля высева семян различных культур необходимы унифицированные датчики. (Цель исследования) Разработать датчик высева емкостного типа, теоретически обосновав его конструктивные параметры и место установки датчика на сеялке. (Материалы и методы). Провели теоретические расчеты траекторий полета семян для механического и пневматического высевающих аппаратов с помощью программных комплексов Mathcad и MicrosoftExel при скорости вращения диска высевающего аппарата 11,5; 17,5 и 26,0 оборотов в минуту. Выполнили расчет электрических параметров разрабатываемого датчика высева. Изучили траектории с помощью высокоскоростной съемки высева на экспериментальной установке c последующей обработкой полученных видеоматериалов. Разработали программное обеспечение для лабораторных исследований оптимального угла установки датчика, чтобы минимизировать время пролета семян через чувствительную зону датчика, и как следствие – повысить разрешающую способность датчика. Изучили несколько вариантов установки датчика под различными углами в диапазоне от 0 до 67,5 градуса, с шагом 22,5 градуса. (Результаты и обсуждение) Получили геометрические и электрические параметры разрабатываемого датчика высева. Определили оптимальные место и положение установки датчика. (Выводы) Выявили, что длина чувствительной зоны датчика составит не менее 55 миллиметров. В ходе лабораторных исследований получили данные, схожие с результатами расчетов. Относительное значение коэффициента сходимости между полученными экспериментально и теоретическими показателями не превышает 0,55 при условии, что данные значения получены на расстоянии, которое меньше радиуса семян. Рассчитали электрические параметры датчика и минимальное расстояние между обкладками датчика, составляющее 20 миллиметров. Установили, что для надежной регистрации отдельных семян высота чувствительной зоны должна быть не менее 5 миллиметров. Создали экспериментальный датчик высева, с помощью которого определили оптимальный угол и место установки датчика. Заключили, что для минимизации времени пролета семян в чувствительной зоне датчика необходимо устанавливать его перпендикулярно траектории полета семян

Invasive Candidiasis in Adult Patients with COVID-19: Results of a Multicenter Study in St. Petersburg, Russia

We studied the risk factors, etiology, clinical manifestations, and treatment outcomes of COVID-19-associated invasive candidiasis (COVID-IC) in adult patients admitted to six medical facilities in St. Petersburg. (November 2020–December 2022). In this retrospective study, we included 72 patients with COVID-IC with a median age of 61 years (range 29–96), 51% of whom were women. The predisposing factors for COVID-IC were a central venous catheter (CVC) for more than 10 days (the odds ratio (OR) = 70 [15–309]), abdominal surgical treatment performed in the previous 2 weeks (OR = 8.8 [1.9–40.3]), bacteremia (OR = 10.6 [4.8–23.3]), pulmonary ventilation (OR = 12.9 [5.9–28.4]), and hemodialysis (OR = 11.5 [2.5–50.8]). The signs and symptoms of COVID-IC were non-specific: fever (59%), renal failure (33%), liver failure (23%), and cardiovascular failure (10%). Candida albicans (41%) predominated among the pathogens of the candidemia. The multidrug-resistant Candida species C. auris (23%) and C. glabrata (5%) were also identified. Empirical therapy was used in 21% of COVID-IC patients: azole-93%, echinocandin–7%. The majority of COVID-IC patients (79%) received, after laboratory confirmation of the diagnosis of IC, fluconazole (47%), voriconazole (25%), echinocandin (26%), and amphotericin B (2)%. The 30 days overall survival rate was 45%. The prognosis worsened concomitant bacteremia, hemodialysis, and long-term therapy by systemic glucocorticosteroids (SGCs), bronchial colonization with Candida spp. The survival prognosis was improved by the early change/replacement of CVC (within 24 h), the initiation of empirical therapy, and the use of echinocandin. Conclusions: We highlighted the risk factors that predispose COVID-19 patients to candidiasis and worsen the survival prognosis. Their individual effects in patients with COVID-19 must be well understood to prevent the development of opportunistic co-infections that drastically lower chances of survival

COVID-19-Associated Pulmonary Aspergillosis in Russia

We studied the risk factors, etiology, clinical features and the effectiveness of therapy of COVID-19-associated pulmonary aspergillosis (CAPA) in adult patients. In this retrospective study, we included 45 patients with proven (7%) and probable (93%) CAPA. The ECMM/ISHAM, 2020 criteria were used to diagnose CAPA. A case-control study was conducted to study the risk factors of CAPA; the control group included 90 adult COVID-19 patients without IA. In CAPA patients, the main underlying diseases were diabetes mellitus (33%), and hematological and oncological diseases (31%). The probability of CAPA developing significantly increased with lymphocytopenia >10 days (OR = 8.156 (3.056–21.771), p = 0.001), decompensated diabetes mellitus (29% vs. 7%, (OR = 5.688 (1.991–16.246), p = 0.001)), use of glucocorticosteroids (GCS) in prednisolone-equivalent dose > 60 mg/day (OR = 4.493 (1.896–10.647), p = 0.001) and monoclonal antibodies to IL-1ß and IL-6 (OR = 2.880 (1.272–6.518), p = 0.01). The main area of localization of CAPA was the lungs (100%). The clinical features of CAPA were fever (98% vs. 85%, p = 0.007), cough (89% vs. 72%, p = 0.002) and hemoptysis (36% vs. 3%, p = 0.0001). Overall, 71% of patients were in intensive care units (ICU) (median—15.5 (5–60) days), mechanical ventilation was used in 52% of cases, and acute respiratory distress syndrome (ARDS) occurred at a rate of 31%. The lung CT scan features of CAPA were bilateral (93%) lung tissue consolidation (89% vs. 59%, p = 0.004) and destruction (47% vs. 1%, p = 0.00001), and hydrothorax (26% vs. 11%, p = 0.03). The main pathogens were A. fumigatus (44%) and A. niger (31%). The overall survival rate after 12 weeks was 47.2%