Investigations on thermodynamic processes of a novel pneumatic drive asymmetric Gifford-McMahon cycle cryorefrigerator

In this paper, a numerical and experimental investigation is conducted on a novel pneumatic-drive asymmetric Gifford-McMahon cycle cryorefrigerator for the first time. In the pneumatic-drive asymmetric Gifford-McMahon cycle cryorefrigerator, the duration of the assistance space exhaust process is kept higher than that of the assistance space intake process. Therefore, the displacer moves faster at the lower dead centre and slower at the upper dead centre inside the expander cylinder, which makes the duration of expansion process longer. The numerical model solves the governing equations of the refrigerant and dynamics of free-floating displacer iteratively to illustrate the refrigeration mechanisms. Additionally, the model computes the performance parameters of the cryorefrigerator, like refrigerating capacity, and specific refrigerating capacity. By adopting the numerical model, the impact of the loitering time on the thermodynamic processes is elaborated. It is perceived that, both refrigerating capacity and specific refrigerating capacity reduces with an increase in the loitering time. The experimental cooling characteristics are studied for different values of discharge to suction pressure ratios of helium compressor.

Mathematical modelling of the selective deep water intake process in a non-prismatic continuously stratified reservoir

Разработана математическая модель селективного водозаборного процесса в узко-глубоком непризматическом водоеме при наличии в нем прямой непрерывной плотностной стратификации. Модель представляет контактную краевую задачу потенциального движения воды в указанном водоеме. Движение воды обусловлено забором воды через два окна, устроенных одно над другим на напорной грани водоема. Учтена непризматическая конфигурация водоема в плане и по вертикали. Непризматические конфигурации описаны экспоненциальными функциями. В результате аналитического решения поставленной контактной краевой задачи получена совокупность расчетных формул, которая с привлечением конечноразностного метода Рунге-Кутты и компьютерных вычислительных систем позволила построить линии тока, приходящие к верхней кромке нижнего водозаборного окна. Вычислительные эксперименты показали, что по мере увеличения скорости потока воды через верхнее окно указанные линии тока опускаются вниз. При этом становится возможным управлять водозаборным процессом через нижнее окно с тем расчетом, чтобы в нижнее окно вода поступала из нижних холодных слоев водоема, что часто бывает необходимо для нужд теплоотвода от тепловыделяющих устройств предприятий, в том числе тепловых и атомных электростанций. Purpose. Mathematical simulation of the selective water intake process in a non-prismatic reservoir in the presence of continuous density stratification. Methodology. Water intake is carried out through two windows arranged one above the other on the pressure face of the reservoir. The non-prismatic configuration of the reservoir both in vertical and horizontal planes is taken into account. The contact initial-boundary value problem of the theory for surface and internal gravitational waves in an ideal incompressible fluid is used. Findings. As a result of the analytical solution of the mathematical model, a set of calculation formulas was obtained, which allows calculating the current lines coming to the upper edge of the lower water intake window. Originality/value. Authors obtain a set of formulas for the components of the water velocity vector. Using the set, a nonlinear boundary value problem is posed and solved for calculation of the current line coming to the upper edge of the lower water intake window by the finite-difference Runge-Kutta method. Based on the results of computational experiments, authors proved that the longitudinal and vertical non-prismatic configuration of a stratified reservoir significantly affects the process of selective water intake. It is proved that as the rate of water intake through the upper window increases, the thickness of the active layer from which water is taken through the lower window decreases to a certain minimum value. This hydrodynamic effect allows taking water from the deep cold layers of the reservoir

Barriers to Referral for Chimeric Antigen Receptor T Cell (CAR-T) Therapies Among U.S. Community Hematologists/Oncologists (cH/O)

Introduction: As of July 31, 2021, 5 CAR-T therapies have been approved in the U.S. to treat lymphomas (large B cell, follicular, and mantle cell), acute lymphoblastic leukemia, and multiple myeloma. These individualized, autologous cell therapies are expensive; involve complex manufacturing, transportation, and storage requirements; and have a unique set of serious adverse events associated with their use. Thus, the use of CAR-T therapies is limited mainly to tertiary care centers that have been licensed to administer these agents. Over half of all U.S. patients with cancer are treated in community-based oncology practices. Understanding the adoption of novel therapies by community hematologists/oncologists (cH/O) is critical to assessing their future utilization and impact on clinical outcomes in the real-world setting. We have assessed CAR-T adoption among cH/O in lymphoma (Gajra et al. Immunotherapy. PMID: 32552151) and with the expansion in number of agents and indications, we sought to assess the evolution of their use of, referrals for, and barriers to CAR-T therapy. Methods: Between January and April 2021, oncologists from across the U.S. were invited to complete a web-based survey about their CAR-T therapy utilization, referral patterns, barriers experienced, and overall impression of this class of therapy. Participant demographics and practice characteristics were also captured in the survey. Participants were not aware of the specific content of the survey as other areas in hematology/oncology were also addressed. Participants were compensated for their participation. Responses were aggregated and analyzed using descriptive statistics. Results: Of the 371 cH/O invited, 100% completed the survey; 63% identified their primary specialty as hematology oncology and 36% medical oncology. The median time in practice was 16 years with a median of 20 patients seen per day on clinic days. The top 3 hematologic malignancies treated by survey participants are CLL, AML, and B-cell NHL. Among the participants, 72% and 53% have referred patients for CAR-T therapy since the first approval and the preceding 6 months respectively; 16% of those who referred in preceding 6 months, reported that none of their referrals ultimately received the CAR-T product infusion. The top 2 barriers impacting timely referral for these participants include a slow approval process by payers (34%) and a slow intake process at the CAR-T center itself (23%). While patient deterioration is a significant challenge to 40% of the participants, other CAR-T center-related challenges perceived by the participants include the CAR-T product not being manufactured, lack of communication from the CAR-T center during the process, and lack of clear instructions to the referring oncologist about follow-up care. Common perceived barriers to prescribing/recommending CAR-T therapy include lack of long-term survival data (14%), therapy-related toxicity (30%), cumbersome logistics of administration (37%), and cost (39%). Among 309 participants queried about cost, 60% feel the price is acceptable for this breakthrough therapy. To facilitate their prescribing/recommendation of CAR-T therapies, the participants agreed that better support to community providers regarding post therapy management, easier referral process to CAR-T centers, timelier approval from payers, and more long-term clinical trial and real-world data are needed. As more CAR-T therapies gain approval and come to market, additional resources requested by the participants included more financial aid/support for patients (59%), more education for prescribing physicians (53%) and patients (29%), more decision support tools (38%), and better coordination and communication between community physicians and sites of care (37%). Conclusions: Most cH/O surveyed have referred patients for CAR-T therapies in hematologic malignancies but there is room for improvement in the referral and intake process as well as the treatment and post-infusion phase. Significant barriers of logistics and cost are potential deterrents to appropriate use. cH/O would welcome additional resources to aid the utilization of CAR-T. These results can inform stakeholders (manufacturers, payers, hospitals, and practices) regarding the need to improve processes and develop payment models to address cost in order to facilitate access of these agents to the appropriate patients. Figure 1 Figure 1. Disclosures Gajra: Cardinal Health: Current Employment, Current equity holder in publicly-traded company. Jeune-Smith: Cardinal Health: Current Employment. Feinberg: Cardinal Health: Current Employment.

40. Impact of an Antimicrobial Intake Process within a Post-acute Medical System

Background Implementation of antimicrobial stewardship programs (ASPs) within long-term acute care facilities (LTACs) is challenging due to limited resources and missing patient data from transferring facilities. In October 2018, an ASP was established within a 43-hopital system consisting of LTACs and rehabilitation hospitals. Despite the presence of a restricted antimicrobial policy, increased utilization was observed for five restricted antimicrobials. The system ASP committee implemented a multipronged approach to optimize utilization of these five agents. Investigators sought to assess the impact of an antimicrobial intake process on antimicrobial consumption. Methods This was a retrospective analysis within a 43-hospital system of LTACs and rehabilitation hospitals, comparing use of five restricted antibiotics before (Jul19-Jun20) and after (Jul20-Apr21) implementation of a data-collection and system review process. An antibiotic intake form and process for review for five restricted antibiotics (ceftaroline, ceftazidime/avibactam, ceftolozane/tazobactam, fidaxomicin, meropenem/vaborbactam) was approved at the system ASP committee. The intake form consisted of a restricted antibiotic form, cultures and susceptibilities, physician notes, and other pertinent data. Any orders for the five antibiotics required completion of an intake form and submission to system ASP members for review and recommendations. Antibiotic consumption was measured in cost per acute patient day (cost/pd) using a 2-sided t-test. Results Post-implementation, the five restricted antibiotics comprised 29.1% of the total antibiotic expenditure for the healthcare system compared to 35.6% pre-implementation. Ten months after program implementation, the total antibiotic cost/PD decreased 29.45% [(&12.02 ± 2.29) vs. (&8.48 ± 1.45); p=0.0003]. The cost/PD of the five restricted antibiotics decreased 42.52% [(&4.28 ± 1.09) vs. (&2.46 ± 0.99) ; p=0.0005]. Conclusion Implementation of an antimicrobial intake process within a post-acute medical system resulted in a significant reduction in antibiotic consumption for five targeted antibiotics as well as overall antibiotic expenditure. Disclosures All Authors: No reported disclosures

System-wide depression screening implementation in ambulatory oncology care: Key strategies and early implementation outcomes.

260 Background: Oncology Care Model (OCM) requires cancer programs to provide depression screening during each care episode to meet the quality measure benchmark of 85% screening rate. This quality improvement (QI) project aims to assess 1) key strategies to integrate system-wide depression screening into routine cancer care, and 2) early outcomes of depression screening implementation. Methods: A mixed-method study design was used to assess strategies to implement routine depression screening in a southeast comprehensive cancer center between July 2019 and December 2020. Two top high-volume hematological oncology clinics that covers sixty percent of ambulatory care participated in the depression screening implementation. Data were collected using 1) depression screening completion rate during OCM performance periods, 2) needs assessment to identify barriers and facilitators of implementation, and 3) semi-structured interviews to assess staff and provider feedback on sustainable implementation strategies. Data were analyzed using descriptive analysis for quantitative outcomes and thematic analysis for qualitative outcomes. Results: A total of 64 hematological oncology providers (n = 22) and staff (n = 42) participated in the depression screening implementation training during three OCM performance periods. Depression screening rate of total ambulatory oncology care increased from 12% (OCM-PR 5, Jul-Dec 19), to 51% (OCM-PR 6, Jan-Jun 20) to 77% (OCM-PR 7, Jul-Dec 20) after the two top-volume clinics integrated depression screening into clinic intake process. Themes emerged from needs assessment revealed multi-level implementation strategies including 1) patient education and psycho-oncological care, 2) staff training and practice modification, 3) provider education & interdisciplinary Care, 4) leadership, administration, and staffing support, and 5) clinical informatics collaboration to build the infrastructure for integrating depression screen with clinic intake in the electronic medical record (EMR). Feedback from staff and provider interviews indicated high receptiveness and buy-in, especially during the COVID-19 pandemic to improve timely identification and triage of patients with depressive symptoms across all oncology care services. Conclusions: Depression screening is a key component of quality comprehensive cancer care that aims to provide timely identification and triage of cancer patients needing follow-up psychosocial care. Early implementation outcomes revealed significant improvement in depression screening completion rate after two clinics adopted depression screening into intake process. Further investigation is needed to refine system-wide implementation strategies across all ambulatory oncology sites and to assess long-term implementation outcomes meet the psychosocial care needs of cancer patients.

On the use of particle image velocimetry (PIV) data for the validation of Reynolds averaged Navier-Stokes (RANS) simulations during the intake process of a spark ignition direct injection (SIDI) engine

Computational fluid dynamics (CFD) simulations of the in-cylinder flow field are widely used in the design of internal combustion engines (ICEs) and must be validated against experimental measurements to enable a robust predictive capability. Such validation is complicated by the presence of both large-scale cycle-to-cycle variations and small-scale turbulent fluctuations in experimental measurements of in-cylinder flow fields. Reynolds averaged Navier-Stokes (RANS) simulations provide overall flow structures with acceptable accuracy and affordable computational cost for widespread industrial applications. Due to the nature of averaging physical parameters in RANS, its validation against experimental results obtained by particle image velocimetry (PIV) requires consideration of how best to average or filter the measured turbulent flows. In this paper, PIV measurements on the cross-tumble plane were recorded every five crank angle degrees for [Formula: see text] cycles during the intake process of a motored, optically accessible spark ignition direct injection (SIDI) engine. Several methods including ensemble averaging, speed-based averaging and low-order proper orthogonal decomposition (POD) reconstruction were applied to remove the fluctuations from experimental PIV vector fields and thus enable comparison to RANS simulations. Quantitative comparison metrics were used to evaluate the performances of each method in representing the intake jet. Recommendations are made on how to provide a fair validation between measured data and simulation results in highly fluctuating flow fields such as the engine intake jet.

MULTI-AGENT SIMULATION MODELING OF MILK INTAKE PROCESS

The article is devoted to the creation of a multi-agent simulation model of the production process of receiving and storing milk; the description of the main parameters and the results obtained during the work with experiments with the model, as well as the description of the implementation of the multi-agent system using the Anylogic simulation environment are given. The introduction of multi-agent simulation methods allows to use digital tools to create a virtual copy of a real process with the ability to predict and identify food production facilities. The usage of simulation modeling is necessary for conducting experiments aimed at improving production processes through virtual testing.

Spray nozzle on the gas injector of the internal combustion engine

The design of the nozzle on the gas injector for gas and gas-diesel engines with distributed and phased gas supply is proposed to increase the uniformity of the gas-air mixture entering the engine cylinders during the intake process. A method for calculating the flow capacity of the nozzle through the pressure drop is given, which adequately assesses the effect of the nozzle design on the gas supply conditions, which will allow adjusting the settings of the gas fuel supply system in a real engine.

Mathematical modelling of the method for controlling selective water intake process in a stratified reservoir

Разработана математическая модель способа управления селективным водозаборным процессом, когда вода забирается из водоема с вертикальной непрерывной температурной стратификацией. Предлагаемый способ обеспечивает снабжение холодной водой систем технического водоснабжения ТЭС, АЭС, предприятий. Составленная математическая модель представляет стационарную краевую задачу гидродинамики мало сжимаемой жидкости. Сжимаемость обусловлена вертикальной температурной стратификацией. В результате решения поставленной краевой задачи определены проекции вектора скорости, вычислена линия тока, приходящая к верхней кромке донного водозаборного окна. По мере увеличения скорости водозабора через вспомогательное окно упомянутая линия тока опускается вертикально вниз и температура забираемой через нижнее окно воды уменьшается. Составляющие вектора скорости движения воды в водоеме вычислены строгими аналитическими методами математической физики. Линии тока рассчитаны методами конечных разностей Рунге - Кутты. The purpose of this study is to develop a mathematical model of a method for controlling selective water intake process, when water is taken from a reservoir with continuous vertical temperature stratification. The methodology for solving the problem implies that water is taken from the reservoir through a window, which is adjacent to the bottom of reservoir. The water intake process is controlled by varying the rate of water intake through an auxiliary window located above the main bottom window. As the speed of water intake through the auxiliary window increases, the thickness of the active layer of water entering the opening of the bottom window decreases. The average temperature of water taken through the bottom window is shown to decrease. The stationary boundary value problem for hydrodynamics of a slightly compressible fluid is chosen as a mathematical model. In the immediate vicinity of the vertical pressure head of the reservoir, the velocity field was calculated using the theory of the boundary layer. Further, a nonlinear boundary value problem was posed that simulates the position of the streamline coming to the upper edge of the lower water intake window. The boundary value problem is solved by the Runge - Kutta finite-difference method. A set of formulas for calculating the velocity field of fluid flow was then obtained. Originality/value: 1. A new original method for controlling selective water intake in a reservoir with continuous vertical temperature stratification has been developed and theoretically justified. The method allows taking water exclusively from the deep-cold layers of the reservoir. 2. The value of the method leads to a technical solution - the installation of an additional upper water intake window above the bottom intake one. This allows controlling the temperature of water used in technical water supply systems of thermal power stations, nuclear power plants and enterprises. 3. An adequate mathematical model for the proposed method was developed and solved. Based on this model, a set of calculation formulas that allow controlling the temperature of the extracted water is obtained.

Physical simulation of thermomechanics of gas flows in the output channels of turbocharger centrifugal compressor

It is known that the thermal and mechanical characteristics of the air flow in the output channel of the turbocharger compressor largely determine the efficiency and quality of the gas exchange processes of the piston engine. The research was carried out on an experimental installation containing a turbocharger, output channels of different configurations, a measurement database and a data collection system. It was found that the stabilization of the flow in the output channel of the compressor leads to a significant increase in the heat transfer intensity (up to 25 %) compared to the base pipeline, while reducing the degree of turbulence by up to 30 %. In the output channel of the compressor with grooves, there is an even more significant increase in the heat transfer intensity (up to 30 %) with an increase in the degree of turbulence by up to 12% compared to the base channel. The proposed configurations of the compressor output channels can be used to intensify heat exchange in order to naturally cool the air during the intake process, as well as to stabilize the gas dynamic parameters of the flow in order to reduce the hydraulic resistance of the intake system of the turbocharged engine.