Computational Tools Research Articles

Influence of HLA-B Leader (-21M/T) Dimorphism With Bw4/Bw6 Epitopes on Graft Versus Host Disease After Allogenic Haematopoietic Stem Cell Transplantation in North Indians.

High degree of variability in human leukocyte antigens (HLAs) system restricts availability of histocompatible HLA-matched-related donors, thus increasing reliance on worldwide bone marrow registries network. Nevertheless, due to limited coverage/accessibility/affordability of some ethnicities in these registries, haploidentical haematopoietic stem cell transplantation (HSCT) emerged as an alternative option, though with allorecognition-mediated graft versus host disease (GvHD) (>40% cases). A dimorphism [-21 methionine (M) or threonine (T)] in HLA-B leader peptide (exon 1) which differentially influences its HLA-E binding, plausibly regulates natural killer cell functionality, affecting GvHD vulnerability and clinically in practice for donor selection. Here, we analysed population-specific influence of this functionally relevant dimorphism on post HSCT GvHD occurrence and clinical utility (if any) towards defining donor permissibility. High resolution HLA-B genotyping data were analysed in 178 study participants, including 89 HSCT patient-donor pairs, for the frequency distribution of -21 leader dimorphism. Distribution of HLA-Bw4/Bw6 was deduced with killer cell immunoglobulin receptor ligand calculator tool in IPD-IMGT/HLA database. Though -21T (∼85%) was over represented in the study participants, no significant influence is observed for this variant between HLA-identical v/s haplo HSCT either with or without GvHD, at allelic and genotypic levels as well as in BLEAT (HLA-B Leader Assessment Tool)-based donor-recipient matching. Stratified analysis of -21M/T into Bw4/Bw6 groups revealed a higher frequency of -21T+Bw4 in GvHD (+) group compared to GvHD (-) (p<0.05), plausibly linking this haplotype with occurrence of GvHD post HSCT and importance of HLA class I-mediated NK cell functionality in GvHD.

Degree of Burn: A Digital Tool for Burn Area Assessment and Fluid Requirement Calculation Using Wound Image Analysis

Burns are tissue damage due to contact with a heat source, such as fire, hot water, chemicals, electricity, or radiation. Burns are a type of trauma with high morbidity and mortality rates and require high treatment costs. In Indonesia, burns are still a serious problem that requires special care, high costs, and skilled personnel. Currently, burn assessments are carried out manually, which is time-consuming and the results are subjective. Treatment efforts include preventing infection and encouraging epithelial cell regeneration to close the wound. Therefore, innovation is needed in the form of a system that helps assess burns more effectively, including classifying wound tissue, measuring wound area, and monitoring wound development. The use of an Android-based system can provide more accurate measurements through a digital planimetry approach or image segmentation, which can identify wound boundaries and tissue types. Technology-based health applications, such as the "Degree of Burn" application, allow for more efficient calculation of burn area and fluid requirements. This study uses a literature review method from international journals, national journals, books, and conference results related to burn assessment to support the development of this system.

STRATEGIC NOISE MAP FOR BELGRADE NIKOLA TESLA AIRPORT

Environmental noise management is a critical aspect of public health policy, particularly within the European Union, which established Directive 2002/49/EC to standardize noise assessment and mitigation efforts across member states. Serbia has integrated the Directive's provisions through its Law on Environmental Noise Protection and accompanying by-laws. This paper presents the strategic noise mapping process for Belgrade Nikola Tesla Airport, Serbia's largest international airport, marking a significant milestone as it is the first time a strategic noise map is being developed for a major airport in Serbia. The legal framework, methodology, and results of this mapping process are discussed in detail. Utilizing the CNOSSOS-EU:2015 method and the Aviation Environmental Design Tool (AEDT) for acoustic calculations, the study defines the affected areas, noise indicators, and population exposure based on 2023 air traffic data. The results indicate that the Lden noise levels exceeding 55 dB impacted 24,223 residents, while the Lnight noise levels exceeding 50 dB affected 7,493 residents. The analysis also includes the estimated number of dwellings, schools, hospitals, and people affected by different noise levels, providing necessary data for developing action plans aimed at mitigating noise pollution. Additionally, the study examines the potential health impacts, including population annoyance and sleep disturbance, using dose-effect relationships as defined by the European Commission. The results underline the importance of ongoing noise monitoring and the need for timely revisions of strategic noise maps and action plans to ensure compliance with both national and EU regulations. This research contributes to the broader effort of environmental noise management, offering insights into the methodologies and challenges of strategic noise mapping for airports in Serbia.

Real-world evaluation of the accuracy of the Viz.AI automated intracranial hemorrhage volume calculation tool

BackgroundAppropriate management of spontaneous intracerebral hemorrhage (ICH) and intraventricular hemorrhage (IVH) requires rapid, accurate volume estimation. Viz.AI has developed an artificial intelligence (AI)-powered ICH calculation tool that may improve existing...

What Quantum Can Learn from Classical Computer Engineering

Quantum computing represents a paradigm shift requiring reconceptualization of algorithms, architectures, and software. Although much is new, there is much that quantum computing can learn from traditional classical computer engineering. In this Special Issue, we focus on examples of quantum research inspired by classical computer engineering, ranging from quantum machine learning and image processing to the extension of the “multi-core” concept to quantum computing. Hardware/software co-design is difficult when communities have their unique jargon and disjoint problem domains. For parallel programming on classical computers, an approach for communicating application developer needs emerged around identifying key bottlenecks that limited software. It was difficult to guess features of future applications, but experienced developers knew features of a computer system that would limit software performance. For each feature, a small kernel was developed with the idea that if the kernel ran well, a system would be an effective system for application developers. This set of kernels was called the Parallel Research Kernels . They have been useful to guide design of parallel computers. We hypothesize that an analogous tool for quantum computing, called Quantum Research Kernels , may aid hardware/software co-design of quantum computing systems. In this article, we motivate the Quantum Research Kernels and provide working examples.

Implementation of Building Information Modeling (BIM) Utilizing Tekla Structures for Work Volume Calculation (Institute of Technology Keling Kumang Project in Sekadau District)

In the construction industry, planners use contract drawings and the Work Plan and Conditions (RKS) to determine the work to complete. The conventional approach in calculating the volume and quantity of work usually relies on Microsoft Excel as a calculation tool based on AutoCAD drawings. However, this method is considered inefficient and time-consuming, which can affect the quality of the resulting infrastructure. Building Information Modeling (BIM) is a solution to improve efficiency in planning and managing construction projects. In this research, Tekla Structures was chosen for its ability to generate project drawings, manage and monitor projects, amplify details with high accuracy, and automatically calculate the volume of work after modelling. This research aims to encourage wider application of digital technology in the construction industry in Indonesia. The results showed that comparing the total volume of concrete work between the calculation using Tekla Structures and secondary data had an accuracy rate of 87.61%, with a deviation of 12.39%. Meanwhile, the total volume of reinforcement works showed an accuracy of 95.66% with a deviation of 4.34%. This insignificant volume difference indicates that Tekla Structures can be relied upon to calculate the volume of work, especially in detailing and reinforcement. Although the accuracy of volume calculation is already high, improvement of the BIM model is still needed to make it closer to the actual conditions in the field. One of the efforts that can be made is to integrate real-time data from the field into the BIM model so that the accuracy of calculations increases and can support planning and project management more effectively.

Fracture Risk Assessment in the 2023 Osteoporosis Canada Guideline.

Radiologists and other diagnostic imaging specialists play a pivotal role in the management of osteoporosis, a highly prevalent condition of reduced bone strength and increased fracture risk. Bone mineral density (BMD) measurement with dual-energy X-ray absorptiometry (DXA) is a critical component of identifying individuals at high risk for fracture. Strategies to prevent fractures are consolidated in the Osteoporosis Canada clinical practice guideline which was updated in 2023. In this guideline, treatment recommendations are based upon a consideration of fracture history, 10-year major osteoporotic fracture (MOF) risk, and BMD T-score in conjunction with age. The current review aims to familiarize radiologists and other diagnostic imaging specialists with the reporting requirements needed to support implementation of this guideline using the FRAX™ risk calculation tool. Fortunately, for specialists already familiar with the Canadian Association of Radiologists and Osteoporosis Canada (CAROC) tool, the transition to FRAX-based reporting is readily accommodated in a radiology workflow.

Pengaruh Kelas Sosial, Gaya Hidup Dan Kualitas Produk Terhadap Keputusan Pemebelian Di Rocket Chicken Cokroaminoto Kota Probolinggo

This research was conducted at Rocket Chicken Cokroaminoto, Probolinggo City, which aims to determine the impact of social class, lifestyle and product quality on purchasing decisions at Rocket Chicken Cokroaminoto, Probolinggo City. Population used by consumers who made purchases in October 2023 at Rocket Chicken Cokroaminoto, Probolinggo City. The sample in this study used a simple random sampling technique, totaling 80 Rocket Chicken Cokroaminoto consumers, Probolinggo City. The data analysis technique used is SPSS (statistical package for the social sciences) through multiple linear analysis calculation tools. The results of this research show: (1) Social class, lifestyle and product quality variables have a positive and significant influence on purchasing decisions, (2) Product quality variables have a dominant influence on purchasing decisions.

PASSIVE FLOW CONTROL AROUND A NACA4415 AIRFOIL BY MEANS OF VORTEX GENERATORS

The present paper intends to improve the aerodynamic performance of a NACA4415 airfoil using low-profile vortex generators. Numerical flow analysis yielded the values of the lift and drag coefficients for impacts ranging from incidence 0&amp;deg; to 24&amp;deg;. The steady Reynolds averaged Navier Stokes equations have been solved with the ANSYS CFX 2019 R2 calculation tool utilizing the shear stress transport turbulence model at a Reynolds number Re &amp;#61; 2.13 &amp;times; 10&lt;sup&gt;5&lt;/sup&gt;. The approach of tetra-mixed meshing was employed. The impact of several parameters (height, span-wise distance, installation angle &amp;beta;, skew angle &amp;phi;) have been investigated. Experimental data has been used to validate the results. According to the numerical outcomes, the skewed angle vortex generators (&amp;Phi; &amp;#61; 20&amp;deg;) placed upstream of the separation zone with a short spanwise distance are beneficial for delaying the stall angle from &amp;alpha; &amp;#61; 20&amp;deg; (clean airfoil) to &amp;alpha; &amp;#61; 24&amp;deg; and enhance the lift coefficient by 39&amp;#37;. However, the overall optimal lift-to-drag ratio was achieved when &amp;phi; &amp;#61; 0&amp;deg;.

Walking and cycling friendliness as proxies to retrofit active transport infrastructure

Active transport modes, such as walking and cycling, have been promoted by scientific studies and policy-makers due to congestion-reduction and health benefits, and low environmental impact. However, adequate infrastructure is necessary for citizens to exercise their choice for those modes. This article presents a case study on the active mode infrastructural condition of a city which, as many others, privileged motorized modes in its growth during the 20th century. Using walking and cycling friendliness as evaluators of the infrastructural condition and a Geographic Information System environment as the calculational tool, an accessibility-based analysis was carried out that enables policymakers to identify the main issues affecting those modes and, most importantly, to pinpoint specific problems that are common to both modes. The methodological approach is scalable to any city size and is a decision-aid tool that can provide value mainly by identifying those common problems which can be efficiently addressed in future infrastructural improvements and maintenance actions. For the case study, common problems turn out to lay along large, distributor roads which fail to provide active travellers with adequate safety from traffic. Based on the results, a concrete intervention plan is proposed, for which a cost-benefit analysis was carried out.

Research on the Method for Solving the Safety Factor of Rock Slope Based on Deformation Monitoring Warning Threshold

In view of the fact that field monitoring information can more intuitively and accurately reflect the stability state of slopes, this paper takes the warning threshold of slope deformation rate monitoring as the slope stability evaluation standard, and puts forward a method for solving the safety coefficient of rocky slopes. The discrete element method (3DEC), which is suitable for rocky slopes, is selected as the numerical calculation tool, the convergence criterion of its strength reduction method is modified to the slope deformation rate threshold, and the method is realized by the bifurcation method through its built-in FISH programming language. The results of the classical case show that, by selecting the slope deformation rate threshold in the appropriate interval, the results of this paper’s method are very close to those of the finite unit stress method and the limit equilibrium method, verifying the reliability of this paper’s method. Further, the method of this paper is applied to an open-pit mine slope project, based on the slope deformation on-site monitoring data and through the time series prediction method to determine the slope deformation rate warning threshold, using the threshold as an evaluation criterion to solve the slope’s coefficient of safety. The calculation results show that the slope’s coefficient of safety in natural working conditions is 1.086, being basically stable. However, with continuous rainfall, the slope’s body gradually becomes saturated, the slope’s coefficient of safety is reduced to 0.987, and the slope’s safety is reduced to 0.987. After continuous rainfall and gradual saturation of the slope, the coefficient of safety decreases to 0.987, resulting in destabilization and destruction, which is consistent with the site conditions.

Emergency Response in Agricultural Industry: Radioecological Lessons from the Kyshtym Accident

The study outlines the various factors that determine the impact of the accident at the “Mayak” chemical plant on agriculture as well as the unique characteristics of the radiation levels in the affected region. In order to guarantee preparedness for any operational response, it is crucial to establish an efficient management structure that can make swift and well-informed decisions. Additionally, having access to emergency plans, prognostic calculation tools, and suitable protocols for handling emergencies are equally essential. These crucial elements are all necessary to ensure that any unexpected event can be addressed promptly and effectively. An analysis of protective measures taken at various times after the Kyshtym accident has been carried out. The paper presents the formulated key takeaways from the Kyshtym accident that pertain to emergency preparedness, the execution of organizational and agrochemical protective measures in agricultural production, and the utilization of accumulated knowledge in both science and practical applications.

Legendre wavelet based numerical method for the solution of marangoni convective flow of dusty ree-erying fluid over a riga plate with activation energy

AbstractLegendre wavelet based numerical method has been developed for the solution of the system of non-linear differential equations arising in the study of a Marangoni convective flow of dusty Ree-Erying fluid over a Riga plate in Darcy-Forchheimer medium with Soret, Dufour, non-linear radiation, activation energy effects and entropy generation analysis. The proposed method is validated by comparing the solutions of the test problem with the Bernoulli wavelet based numerical method and the exact solution and by comparing the results of the considered dusty fluid problem for some fixed parameters with the previously published results. The effects of various factors on the velocity, thermal, concentration attributes are studied by using the proposed method. It is observed that the Ree-Erying fluid parameter and Marangoni ratio parameter escalates the velocity and declines the temperature and concentration. The opposite behaviour is observed for Deborah number. The concentration declines for higher chemical reaction parameter and improves for activation energy. Both entropy generation and Bejan number escalates for radiation parameter and diffusion parameter. The proposed method is reliable, fast computable and powerful tool to solve the differential equations.

Validity of the Skin and UV Neoplasia Transplant Risk Assessment Calculator (SUNTRAC) tool in a Dutch cohort of transplant recipients

AbstractBackgroundTo identify patients with high risk of skin cancer, risk prediction tools have been developed.ObjectivesExternal validation of the Skin and UV Neoplasia Transplant Risk Assessment Calculator (SUNTRAC) in a Dutch cohort of solid organ transplant recipients (SOTR) and exploration of the possibility of incorporating additional risk factors to enhance its predictive performance.MethodsWe used data from the ongoing, prospective TransplantLines Biobank and Cohort Study of the University Medical Center Groningen (Groningen, The Netherlands). We conducted a survival analysis using Fine and Gray models to determine the subdistribution hazard ratios of the SUNTRAC risk factors and groups, Wolbers C index to assess its discriminative power, and cumulative incidences of skin cancer to assess its calibration. We applied the same methods for the incorporation of additional risk factors to the model.ResultsA total of 2099 patients were included with a median age at transplantation of 52.1 years (Interquartile range [IQR]: 40.6–60.1) and a median follow‐up time of 6.6 years (IQR: 3.4–12.5). In total 478 (22.8%) patients developed skin cancer. Basal cell carcinoma (53.3%) and cutaneous squamous cell carcinoma (42.9%) were most prevalent. The cumulative incidences of skin cancer per SUNTRAC risk group at 10 years were: low‐risk (1.8%), medium‐risk (12.9%), high‐risk (34.3%) and very high‐risk (68.6%). Significantly different skin cancer risk rates were observed for the medium‐risk (SHR = 9.9, 95% CI: 2.51–39.4), high‐risk (SHR = 21.5, 95% CI: 5.40–85.2) and very high‐risk (SHR = 80.3, 95% CI: 19.26–335.1) groups in reference to the low‐risk group. Wolbers C‐index at 5 years was 0.71. The model was well calibrated for our cohort. The addition of other potential risk factors yielded no or marginal improvement of discriminative value on top of SUNTRAC.ConclusionsSUNTRAC is valid for the general Dutch SOTR population, and it can be clinically implemented.

Speech and language therapist-led clinics for low-risk suspected head and neck cancer referrals: A qualitative study of ear, nose and throat surgeons' views.

Over 200,000 patients are referred onto the suspected head and neck cancer (HNC) pathway annually in the UK, with around 3% receiving a cancer diagnosis. With new HNC advancements in identifying patients at low risk of a cancer diagnosis, one proposal is a speech and language therapy (SLT)-led first point of contact clinic for low-risk patients presenting with voice or swallowing symptoms. To explore ear, nose and throat (ENT) surgeons' views regarding this model. The study used a qualitative study design using semi-structured interviews. Transcribed responses were analysed using thematic analysis. A total of 11 UK ENT surgeons participated. Themes included the positives and challenges of the proposed model; existing facilitators that increase the likelihood of success; and the requirements for successful implementation. Service variation impacted level of interest. Waiting times were problematic at some sites more than others; SLT workforce issues were of differing prevalence; SLT competence and interest differed; and support from organizational leaders varied. Participants' personal views also varied, for example, acceptability of the model to patients, or what governance structure is required. There was no single SLT-led clinic model suitable for all centres; however, some general principles were identified to inform further evaluation and implementation of this model. Principles included the deployment of SLTs experienced in laryngeal examination and flexible nasendoscopy; dedicated job plans and workforce; professional and regulatory body recognition and support; and clear training, supervision structure and job description for the role. Service outcomes, training protocol and competencies require robust evaluation. What is already known on this subject During the SARS-CoV-2 pandemic, a risk calculator tool was developed to identify patients at highest risk of cancer who were referred to the 2-week-wait (2ww) ENT pathway. These patients require urgent face to face ENT assessment. Lower risk patients with voice and swallowing difficulties still require management of their symptoms and an SLT-led clinic model is one potential solution for this population. While SLTs' views of this model have been explored with a UK-wide survey and focus groups, ENT surgeons' perspectives are yet to be investigated. What this study adds to the existing knowledge This study explores ENT surgeons' views regarding SLT-led clinics for patients who are referred through the 2ww ENT pathway, stratified as being at low risk of cancer, and with voice and/or swallowing symptoms of likely benign aetiology. Participants shared many positive perceptions of the clinic along with factors that they felt would enhance its success (facilitators). Key requirements for the success of this clinic model were also highlighted, along with challenges that need to be addressed. What are the practical and clinical implications of this work? The need for this clinic model varied by centre. However, general principles included the importance of a dedicated workforce with pre-existing relevant expertise; and a clear role profile, training process and competencies framework. Professional, statutory and regulatory bodies' recognition of the role is required, and robust evaluation of the model is necessary.

Case Study: Modifying a Desander Design To Handle Low Flow Rates

The Challenge A major North Sea operator had faced issues with sand filling up the production separator on a late-life well on the Norwegian Continental Shelf. The well was previously shut in due to sand production. A jetting operation was required, with solids to be separated on the water line upstream of the reinjection pumps in order to protect the pumps from erosion damage. The expected solids sizes were fines of 20–150 microns and sand in the 150–800-micron range. Flow rate was estimated at a rate of 240 m3/day. The service provider, Expro, was the main contractor and requested assistance from FourPhase to supply the desanding solution. The Solution When presented with the operational data, the project team immediately understood that the low flow rate would be one of our main challenges. The given rate was in the lower end of the capacity window for our DualFlow cyclone designs. Low inflow pressure causes lower differential pressure in the cyclones, resulting in reduced separation efficiency that we were keen to avoid. Throughout more than 10 years of operation, we have built a solids management database, recording all parameters and separation rates during more than 150,000 operational hours. Where we previously relied on extensive computer simulations with computational fluid dynamics modeling, our database now allows us to calculate the sweet spots of solids separation from existing well parameters without any further expensive and time-consuming modeling. This benefits our customers, as our data increases our ability to quickly determine if a given scenario will work or not. In the described case, our database would serve us well in understanding how we could solve the customer's challenge. Plugging the flow data into a calculation tool coupled to the solids database, we calculated which range of differential pressures we could expect in the cyclones. Another calculation tool projected the separation efficiency of solids as a function of pressure conditions. We quickly found that our regular cyclone design with 100-mm-diameter liners were too large, creating a pressure drop that was not beneficial for separation efficiency. Experience, along with calculations based on database figures drawn from previous operations with low flow rates, pointed toward a smaller cyclone liner insert. We had previously manufactured reduced-size liner inserts to meet separation requirements on operations with lower flow rates. Now, we started to consider even smaller-sized inserts. Our calculations showed that a 50-mm-diameter liner insert would provide the best results under the given circumstances (Fig. 1). Seeking internal quality assurance, the project team aligned with our engineering and operations departments, verifying the calculations. The engineering department then quickly got to work creating 3D-printed prototypes for testing. FourPhase has developed and installed a complete test facility at our headquarters in Bergen, Norway (Fig. 2). The test loop gives us an opportunity to test a variety of equipment in a controlled and safe environment.

Exploring discrepancies in muscle analysis with ImageJ: understanding the impact of tool selection on echo intensity and muscle area measurements.

The aim was to compare the use of different tools within the ImageJ program (polygon vs. segmented line) and their impact on the calculation of muscle area and echo intensity (EI) values in ultrasound imaging of the vastus lateralis muscle. Thirteen volunteers participated in this study. Ultrasound images of the vastus lateralis muscle were acquired using 2D B-mode ultrasonography and analyzed using both the polygon and segmented line tools by the same evaluator. The intraclass correlation coefficient (ICC) and coefficient of variation (CV) assessed the tools' reliability. Bland-Altman plots were employed to verify the agreement between measurements, and linear regression analysis determined proportional bias. A paired t-test was conducted to analyze differences between the tools. The reliability between tools for muscle area calculation was weak (r = 0.000; CV = 138.03 ± 0.34%), while it was excellent for EI (r = 0.871; CV = 15.19 ± 2.96%). The Bland-Altman plots indicated a large bias for muscle area (d = 195.2%) with a proportional bias (p < 0.001). For EI, the bias was (d = 15.2) with proportional bias (p = 0.028). The paired t-test revealed significant differences between the tools for area (p < 0.001) but not for EI (p = 0.060). The study found significant differences in measurements obtained with the polygon and segmented line tools in ImageJ, with the polygon tool showing higher values for muscle area and lower values for EI.

МЕТОДЫ И ИНСТРУМЕНТЫ ИССЛЕДОВАНИЙ ПОКАЗАТЕЛЕЙ ТЯГОВО-СКОРОСТНЫХ СВОЙСТВ И ТОПЛИВНОЙ ЭКОНОМИЧНОСТИ АВТОМОБИЛЬНОЙ ТЕХНИКИ КАМАЗ. ЧАСТЬ 1

Operational indicators of wheeled vehicles (WV), consumption of fuel and lubricants, urea, speed of cargo delivery, have always been and remain one of the key factors ensuring their high efficiency. To improve the efficiency of WV, specialists of KAMAZ PTC have developed and apply in practice both standardized methods of research of these indicators and original methods with appropriate instrumental support. Design and research departments are equipped with tools for analytical calculations, computer modeling, laboratory-road and operational tests, as well as bench equipment for determining input data for calculation models and their validation. The first part of the paper presents the experience of analytical studies. In the second part, the methods of computational and experimental studies will be outlined.

Comparison of simulated and measured coincidence time resolution and energy resolution of scintillation crystals coupled to SiPM device

Scintillating crystal coupled to a silicon photomultiplier SiPM is a typical detection solution in many modern radionuclide imaging systems such as positron emission tomography (PET). Coincidence time resolution (CTR) and energy resolution (ER) are two key performance parameters in the field of time-of-flight PET (ToF-PET). Both CTR and ER are system level parameters related to crystal choice dimension, speed and noise of the read-out electronics, calibration and analysis algorithms, and SiPM performance. In this work, the effect of SiPM photon detection efficiency PDE, single photon time resolution SPTR, and correlated and uncorrelated noise on CTR and ER were studied. For this purpose, analytical calculation and Monte Carlo simulation tools for CTR and ER were developed and tested for the onsemi MicroFJ-60035 SiPM device at different operating bias voltages coupled with LYSO and BGO crystals. The obtained analytical and simulation results were compared with experimental measurements performed with a 22Na source and 3 × 3 × 3 mm3 LSYO crystal wrapped in Teflon reflector and coupled to SiPMs using optical grease. Good agreement between measurements, simulation, and analytical calculation was found for ER at all device working range, and the best ER of ∼ 9% for 511 keV photopeak was found for the 3 × 3 × 3 mm3 LYSO crystal. The CTR was simulated for LYSO crystals with different lengths from 3 mm up to 30 mm and varies from 110 ps (3 mm crystal) up to 170 ps (30 mm crystal). It was compared to experimental measurements performed for 3, 5 and 20 mm crystal length, where CTR was measured from 95 ps (3 mm crystal) up to 140 ps (20 mm crystal). A difference from 5 ps up to 20 ps was found between Monte Carlo simulation and CTR measurements depending on the crystal length. The analytical calculation shows on average ∼ 20 ps worse CTR than experimental measurements. The systematic discrepancy between experimental and simulated CTR values might be related to a difference in light collection efficiency and level of electronics noise used in calculations as well as SiPM PDE angular dependency, while the discrepancy between experimental and analytical CTR might be related to read-out electronics noise which seems to have too high effect on analytical calculation.

Combined electron and proton radiation effects on solar cells for earth orbit

Abstract We present a computational approach for accurate calculations of the combined effects of electron and proton radiation in space, tailored to a specific orbit and accounting for the full range of particle energies. The radiation-induced defect formation is shown to depend on the NIEL (Non-Ionizing Energy Loss), which reflects the small fraction of particle energy (from electrons, protons or other ions) lost through the ionisation of the material. The model developed by the Naval Research Laboratory (NRL) for predicting solar cell degradation based on NIEL aligns closely with the results from the Jet Propulsion Laboratory (JPL). However, the JPL model involves a more comprehensive methodology, incorporating experimental validation. To determine the energy dependence of NIEL, S(E), for both electrons and protons, we use the ESA NIEL calculation tool. This computational process involves assessing the radiation environment and its effects with an assistance from SPENVIS — a simulation platform developed by ESA/NASA for generating spacecraft trajectories in LEO, MEO or GEO. Proton and electron fluxes are simulated using the International Radiation Environment Near Earth (IRENE) model within SPENVIS. This model offers various calculation options — such as mean, percentile, perturbed or Monte Carlo simulations — based on the mission duration and launch date. The resulting proton and electron fluences, both integral and differential, are used to calculate the Displacement Damage Dose (DDD). This is achieved by integrating the product of NIEL with the differential fluences over the relevant particles energy range. To enhance efficiency, specialized software tools have been developed to extract particle fluxes and fluences from SPENVIS, interpolate them and perform the necessary integration to obtain DDD values for protons, electrons and the combined DDD. Equivalent fluences for defined energy ranges are also provided, enabling detailed, mission-specific radiation analyses. These tools streamline the evaluation of the radiation environment and its impact on solar cells, determining the design and material choices for mission planning and providing the data to predict space power generation throughout the mission’s duration.