Standard Production Research Articles

Trueness of five different 3D printing systems including budget- and professional-grade printers: An In vitro study

ProblemSeveral types of 3D printers with different techniques and prices are available on the market. However, results in the literature are inconsistent, and there is no comprehensive agreement on the accuracy of 3D printers of different price categories for dental applications. AimThis study aimed to investigate the accuracy of five different 3D printing systems, including a comparison of budget- and higher-end 3D printing systems, according to a standardized production and evaluation protocol. Material and methodsA maxillary reference model with prepared teeth was created using 16 half-ball markers with a diameter of 1 mm to facilitate measurements. A reference file was fabricated using five different 3D printers. The printed models were scanned and superimposed onto the original standard tesselation language (.stl) file, and digital measurements were performed to assess the 3-dimensional and linear deviations between the reference and test models. ResultsAfter examining the entire surface of the models, we found that 3D printers using Fused filament fabrication (FFF) technology −120.2 (20.3) μm create models with high trueness but high distortion. Distortions along the z-axis were found to be the highest with the stereolithography (SLA)-type 3D printer at −153.7 (38.7) μm. For the 4-unit FPD, we found 201.9 (41.8) μm deviation with the digital light processing (DLP) printer. The largest deviation (−265.1 (55.4) μm) between the second molars was observed for the DLP printer. Between the incisor and the second molar, the best results were produced by the FFF printer with −30.5 (76.7) μm. ConclusionBudget-friendly 3D printers are comparable to professional-grade printers in terms of precision. In general, the cost of a printing system is not a reliable indicator of its level of accuracy.

Effect of Different Regeneration Processes on LID Degradation Mechanisms in B-doped p-type c-Si PERC Solar Cells in Industrial Production

Light-induced degradation (LID) and elevated temperature-induced degradation (LeTID) mechanisms negatively affect the performance of p-type Cz-Si-based solar cells. In this study, the degradation rates under illumination were investigated for non-metallized and metallized PERC cells with different base resistivities at different temperatures. These bifacial PERC cells are produced from own-produced ingots and wafers in a vertically integrated environment. The effect of different regeneration processes, using either illuminated annealing or direct current injection used in standard production against LID, is also investigated.

Literature Review of The Development of a Green Campus Teaching Factory-Based Learning Model in Vocational Schools in Indonesia

This research is a literature review of the development of teaching and learning models in factories developed to create an education system capable of producing industry standard products or services. The literature review method is used in this article with references adapted to the research results. The discussion presented includes an analysis of vocational education about the basic philosophy of vocational education and the characteristics of vocational education, as well as models of administering vocational education. Furthermore, the development of the teaching factory learning model which includes Project-Based Learning (PBL) and Work-Based Learning (WBL) understands the context of its development. A study of the green campus-based teaching factory approach is then reported to determine the factors that influence it. In the final section, potential research and development related to the development of a teaching factory is presented to outline potential studies.

Accuracy of quantitative viral secondary standards: a re-examination.

Interlaboratory agreement of viral load assays depends on accuracy and uniformity of quantitative calibrators. Previous work, published in JCM several years ago, demonstrated poor agreement of secondary cytomegalovirus (CMV) standards with nominal values. This study re-evaluated this issue among commercially produced secondary standards for both BK virus (BKV) and CMV, using digital polymerase chain reaction (dPCR) to compare the materials from three different manufacturers. Overall, standards showed an improved agreement compared to prior work, against nominal values, indicating a substantial improvement in the production of accurate secondary viral standards, while supporting the need for further work in this area and for the broad adaption of international unit (IU) as a reporting standard for quantitative viral load results.

Development of a technique for X-ray fluorescence analysis of zinc-aluminum-magnesium alloys

A technique for X-ray fluorescence spectral analysis of zinc-aluminum- magnesium alloys has been developed, which allows the determination of Mg, Al, Pb, Si, Cu, Mn, Fe, Ni content in the alloy. The effect of the sample preparation method on the linearity of calibration graphs is revealed. The conditions for determining the main alloying (Al, Mg) and impurity (Pb, Fe, Cu, Si, Mn, Ni) elements by X-ray fluorescence spectrometry were studied. It is proposed to use the correction of the matrix effect by selecting alpha coefficients for the intensity of X- ray radiation with subsequent automatic conversion of the function into a linear form. Calibration graphs for determination of the elements in the corresponding ranges, i.e., Mg (0.00019 – 5.04%), Al (0.0002 – 12.4%), Pb (0.0012 – 2.07%), Si (0.0005 – 0.12%), Cu (0.0006 – 5.95%), Mn (0.0004 – 0.00524%), Fe (0.0009 – 0.41%), Ni (0.0009 – 0.27%), were obtained using standard reference samples and production samples of the alloys, the chemical composition of which was previously determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The correctness of the developed methodology was confirmed by analysis of standard samples and comparative analysis of the obtained results using the Student’s t-test.

Evaluation of commercial doses of a feed additive and silymarin on broiler performance with and without CCl4-induced liver damage

Improving productive performance is a daily challenge in the poultry industry. Developing cost-effective additives and strategies that improve performance in antibiotic-free poultry production is critical to maintaining productivity and efficiency. This study evaluates the influence of a commercially available phytogenic feed additive (CA-PFA, that comprises silymarin, betaine and curcumin extracts as main ingredients) and silymarin on commercial broilers' productive performance and liver function with and without carbon tetrachloride (CCl4)-induced liver damage. The experiment was conducted in a completely randomized design, with six treatments, eight replicates, and eight birds per replicate in 18 one-day-old male broilers (Cobb Vantress 500) each; under a 3 × 2 factorial arrangement (3 diets x 2 levels of CCl4, 0 and 1 mL/kg body weight orally). The experimental treatments included 3 diets, commercially recommended doses of CA-PFA (500 mg/kg of feed; this dose provides 70 mg/kg of silymarin, besides the other active ingredients included in the formulation), silymarin (250 mg/kg of feed, containing 28% of active ingredient; this dose provides 70 mg/kg of silymarin as active ingredient) and an additive-free basal diet as a control. A standard commercial silymarin was used as a reference due to its well-known and extensively studied hepatoprotective properties that can mitigate the negative effects of CCl4 in the liver. The data were analyzed as a 2-way ANOVA, and the means showing significant (P ≤ 0.05) differences were then compared using the Post-Hoc Tukey HSD test. No interaction was detected between factors. Exposure to CCl4 had a noticeable detrimental effect on alertness, productive performance, and liver function of broilers without a significant increase in mortality. Including CA-PFA in the diet improved productive performance compared to the basal diet from day 21 to the end of the trial, on day 42. While no influence in feed intake was detected for any treatment, CA-PFA improved body weight gain (BWG) and feed conversion ratio (FCR) significantly (P < 0.05) from day 21 to the end of the trial in healthy and CCl4-exposed birds. The results show that CA-PFA supplementation improves performance parameters in broilers with and without CCl4-induced liver damage, when compared to a basal diet and the addition of a standard commercial silymarin product.

A novel insecticide, isocycloseram, shows promise as an alternative to chlorpyrifos against a direct pest of peanut, Diabrotica undecimpunctata howardi (Coleoptera: Chrysomelidae).

Larvae of the southern corn rootworm (SCR) Diabrotica undecimpunctata howardi Barber (Coleoptera: Chrysomelidae) are primary pests of peanut in the Virginia-Carolina region of the United States, and are relatively sporadic pests in southern states such as Georgia, Alabama, and Florida. Peanuts have strict quality standards which, when they are not met, can diminish crop value by more than 65%. Management of direct pests like SCR is therefore crucial to maintaining the economic viability of the crop. The soil-dwelling nature of SCR larvae complicates management due to difficulties associated with monitoring and predicting infestations. Nonchemical management options are limited in this system; preventative insecticide applications are the most reliable management strategy for at-risk fields. Chlorpyrifos was the standard product for larval SCR management in peanut until its registration was revoked in 2022, leaving no effective chemical management option for larvae. We tested a novel insecticide, isocycloseram, for its ability to reduce pod scarring, pod penetration, and non-SCR pod damage in field studies conducted in Suffolk, Virginia in 2020-2022. Overall injury was low in 2020 and 2022, and in 2022 there was not a significant effect of treatment. In 2021, 2 simulated chemigation applications of isocycloseram in July significantly reduced pod scarring and overall pod injury relative to chlorpyrifos and the untreated control. Our results suggest that isocycloseram may become an effective option for managing SCR in peanut, although more work is needed to understand the mechanisms by which it is effective as a soil-applied insecticide.

Investigation of cost and availability of gluten-free food in Jeddah, KSA

ObjectiveThe prevalence of celiac disease (CD) in KSA is progressively increasing. Consistent adherence to a gluten-free (GF) diet is the only effective CD treatment. The availability and cost of GF food are important factors in adherence to a GFD. The objective of this study was to investigate the cost and availability of GF food in a sample of local stores and supermarkets across Jeddah province in KSA. MethodEleven supermarkets in Jeddah, KSA, ranging from high budget/quality supermarkets to low-budget stores, were visited. Eight food categories were evaluated, including flour, breakfast cereals, breads, pastas, and snacks (e.g., biscuits, cookies, snack bars, and chips). The availability and cost of GF and gluten containing (GC) items within these food categories were recorded. Each item included in these food categories was counted, and the overall average price was calculated. ResultsA total of 233 GF and 24 GC products were found. Supermarket 1 had the highest availability of GF foods (n = 90), followed by supermarket 2 (n = 34), supermarket 3 (n = 30), supermarket 4 (n = 23), supermarket 5 (n = 21), supermarket 6 (n = 18), supermarket 7 (n = 9), and supermarket 8 (n = 8). The median price per 100 g was significantly greater for GF than GC products (p < 0.05). The cost of GF products was significantly higher than that of GC products (p < 0.05); consequently, GF foods were twice as expensive as their GC counterparts. ConclusionThe availability of GF products was limited, and GF products were more expensive than standard GC products. High cost and limited availability are major roadblocks to GFD adherence among people with CD. Governmental organizations must cooperate with healthcare providers and food industries to ensure that GF foods are widely available and affordable for people with CD, to minimize financial pressure and improve health quality.

Efanesoctocog alfa: the renaissance of Factor VIII replacement therapy.

Efanesoctocog alfa (Altuviiio,TM Sanofi-SOBI) is a B domain-deleted single-chain Factor VIII (FVIII) connected to D'D3 domain of von Willebrand Factor (vWF). Its ingenious design allows efanesoctocog alfa to operate independently of endogenous vWF and results in an outstanding 3-4 times longer half-life compared to standard and extended half-life (EHL) FVIII products. The prolonged half-life ensures sustained high levels of factor activity, maintaining normal to near-normal ranges for the majority of the week, facilitating the convenience of once-weekly administration. Efanesoctocog alfa received regulatory approval in 2023 for application in both adults and children with inherited hemophilia A in the United States and Japan. Its sanctioned use encompasses both prophylaxis and 'on demand' treatment for bleeding episodes. The European Medicines Agency (EMA) is currently undertaking a comprehensive review of Altuviiio. TM This comprehensive review focuses on the immunological profile of efanesoctocog alfa, a highly sophisticated new class of EHL FVIII molecule. The integration of the vWF D'D3 domain, XTEN polypeptides, and potential regulatory T-cell epitopes within various segments of efanesoctocog alfa collectively serves as a mitigating factor against the development of a neutralizing T-cell-mediated immune response. We hypothesize that such distinctive attribute may significantly reduce the risk of neutralizing antibodies, particularly in previously untreated patients. The discussion extends beyond regulatory approval to encompass the preclinical and clinical development of efanesoctocog alfa, including considerations for laboratory monitoring. The review also highlights areas that warrant further investigation to deepen our understanding of this groundbreaking therapeutic agent.

Boosting nutritional quality of Urtica dioica L. to resist climate change.

More than ever, traditional agricultural practices need a shift towards more resilient, sustainable, modern and adaptable practices that benefit the health of the planet and people. Today's consumers are constantly on the lookout for novel, highly nutritious foods that have a positive impact on their overall health and well-being. Nettle (Urtica dioica L.) is gaining recognition not only as a popular medicinal plant, but also as a desirable green leafy vegetable rich in phytonutrients. As it is difficult and even expensive to control the quality standards of wild-collected plants, the implementation of sustainable cultivation methods, especially hydroponics, with effective greenhouse management could be a possible solution to obtain a standardized product with high nutritional value. Therefore, the aim of this study was to investigate the effects of four nutrient solutions differing in the content of macro- and micronutrients (especially nitrogen, potassium, calcium, magnesium and iron) and two consecutive cuts on the number of leaves, yield, nitrate and mineral content and the content of specialized metabolites of stinging nettle from a floating hydroponic system. Nettle plants were cultivated in a hydroponic system using the floating hydroponics technique. The two-factorial experiment was performed with nutrient solution and consecutive cuts as factors. The highest yield (2.49 kg/m2) was achieved after the 1st cut with plants cultivated in the nutrient solution with higher nutrient concentration. All tested nutrient solutions resulted in high levels of minerals and bioactive compounds in the plant material (ascorbic acid content of 102.30 mg/100 g fw and total phenolics content of 465.92 mg GAE/100 g fw), confirming floating hydroponics as a sustainable approach for cultivating nettle with enhanced nutritional value and antioxidant potential. It is important to highlight that the nutrient solution with the lowest nutrient composition yielded the highest concentrations of calcium (5.54%) and iron (180.67 mg/kg dw). Furthermore, it exhibited elevated levels of specific phenolic compounds, including caffeoylmaleic acid, ellagic acid, ferulic acid, naringin, and rutin trihydrate. Notably, this solution demonstrated the lowest nitrate content (4225.33 mg/kg fw) in the plant material. Therefore, it can be recommended as a preferable formulation for hydroponic nettle cultivation.

Determination of Balbas Breed Sheep Standard Performance the Grown in the Nakhchivan Autonomous Republic

The determination of the standard productivity of Balbas sheep raised in the Nakhchivan Autonomous Republic has not yet been carried out. For this purpose, the typological characteristics of Balbas breed sheep currently bred in the autonomous republic were studied and divided into three types according to body structure and performance. These are the tough, rough and gentle types. Sheep of a strong type have a height at the withers of 69 cm, an oblique body length of 68 cm, a chest width of 23 cm, a chest depth of 31 cm, a chest girth of 99 cm. Wool yield is 2.0 kg, milk yield is 100 kg per head. For coarse type ewes, these sizes are respectively 70, 68, 24, 33, 102 cm, 1.7 and 90 kg, for gentle type ewes 66, 21, 30, 96 cm, 1.5 kg.

Understanding the setting behaviours of alkali-activated slag from the dissolution-precipitation point of view

Ground granulated blast-furnace slag (GGBS) is widely used as supplementary cementitious material of interest for adjusting the performance of concrete. Unlike standard commercial products, characteristics of GGBS from different iron manufacturers vary significantly and assessment of its reactivity, especially at an early age, is not well-established despite numerous parameters specified in current standard systems. Three GGBSs with different setting features during the alkali-activated process were dissolved in either deionised (DI) water or NaOH solution in this study. To illustrate the fundamental processes of reaction kinetic, the dissolved ion concentrations, glassy structural changes, and chemically bound water were measured using ICP-OES, FTIR, and TG respectively. Meanwhile, thermodynamic calculations were carried out to estimate the precipitation of C–S–H gels, which is directly linked with setting behaviours. The results clearly show the differences in the dissolution of the three GGBSs, which could be used to indicate the activity of GGBS. The GGBS with higher activity (i.e. faster setting during alkali activation) tends to dissolve evenly in DI water, whilst those with lower activity show that the silicate groups with lower polymerisation dissolved faster. The chemically bound water determined by TG analysis and the effective saturation index (ESI) are promising parameters for reflecting the activity of GGBS during dissolution in the alkali media. Although this study demonstrated the dissolution rate of higher polymerised silicate groups in GGBS should be the root for the differences in its activity, more structural information on the glassy phase and the interactions of alkali with the surface of GGBS still require further understanding. It is speculated that the ratio of Al[IV]/Al[V] plays an important role in the activity of GGBS. This finding may shape a certain basic understanding of how GGBSs dissolve in neutral and high pH solutions and highlight a re-evaluation of assumptions in thermodynamic simulation under different conditions.

Barriers to gene therapy, understanding the concerns people with haemophilia have: an exigency sub-study

BackgroundGene therapy has the potential to offer people with haemophilia (PwH) a life free from bleeding and the burden posed by current treatment regimens. To date, gene therapy has only been available in clinical trial settings, to PwH without pre-existing or historical factor inhibitors, significant concomitant liver damage or pre-existing neutralising antibodies to the adeno-associated viruses used to deliver the therapy. Thus, most PwH treated at centres not currently involved in gene therapy trials, either as a referral/follow-up centre or as a dosing centre, have been unable to access the therapy. This Exigency sub-study aims to gain a greater understanding of the opinions of PwH in the United Kingdom who have not had access to gene therapy: asking what they understand, what concerns they have, and whether they perceive any barriers preventing their access to gene therapy.ResultsTwenty-three PwH were approached; 14 consented, and one withdrew prior to interview. The mean age of the participants was 35.7 years (range 25–74 years). Eleven had haemophilia A and two haemophilia B. Two were treated with standard half-life factor products, five with extended half-life products, five with a FVIII mimetic and one with a clinical trial product. One family member (a participant's partner) was also interviewed. The participants identified four barriers to gene therapy: concerns about the process of gene therapy (Expectations), uncertainty about the results (outcomes), (Access) to treatment, and a lack of understanding about gene therapy (education).ConclusionsThis Exigency study subgroup sees gene therapy as a positive treatment development that promises an improved quality of life. For this participant group, four issues impact their decision to undergo gene therapy. If the promise of gene therapy is to be realised, these barriers need to be acknowledged and addressed by healthcare professionals, patient organisations, and gene therapy providers.

A comparative study of Lachancea thermotolerans fermentative performance under standardized wine production conditions

The study explores diverse strains of Lachancea thermotolerans in single-inoculum wine fermentation conditions using synthetic grape must. It aims to analyze the role of the species without external influences like other microorganisms or natural grape must variability. Commercial strains and selected vineyard isolates, untested together previously, are assessed. The research evaluates volatile and non-volatile chemical compounds in final wine, revealing significant strain-based variations. L. thermotolerans notably produces lactic acid and consumes malic acid, exhibiting moderate ethanol levels. The volatile profile displays strain-specific impacts, affecting higher alcohol and ester concentrations compared to S. cerevisiae. These effects vary based on the specific compounds. Using a uniform synthetic must enables direct strain comparisons, eliminating grape-related, environmental, or timing variables in the experiment, facilitating clearer insights into the behavior of L. thermotolerans in wine fermentation. The study compares for the first time all available commercial strains of L. thermotolerans.

Improved Surface Currents from Altimeter-Derived and Sea Surface Temperature Observations: Application to the North Atlantic Ocean

We present a study on the ocean surface currents reconstruction by merging Level-4 (L4, gap-free) altimeter-derived geostrophic currents and satellite sea surface temperature. Building upon past studies on the multi-variate reconstruction of geostrophic currents from satellite observations, we regionalized and optimized an algorithm to improve the altimeter-derived surface circulation estimates in the North Atlantic Ocean. A ten-year-long time series (2010–2019) is presented and validated by means of in situ observations. The newly optimized algorithm allowed us to improve the currents estimate along the main axis of the Gulf Stream and in correspondence of well-known upwelling areas in the North Eastern Atlantic, with percentage improvements of around 15% compared to standard operational altimetry products.

Not all platelet-rich plasma are created equal.

This review aims to elucidate potential variations in clinical outcomes resulting from the use of different types of platelet-rich plasma (PRPs) in reproductive medicine. It seeks to explore the reasons behind the diverse results reported in various studies and assess the general features distinguishing different PRP formulations. PRPs have found applications across diverse medical fields, generating controversy due to the variability in outcomes. The field of reproductive medicine, despite its limited published studies, is encountering a similar challenge as it integrates these treatments. The multitude of PRP product brands in the market, coupled with 'home-made' PRPs, poses a significant barrier to establishing a common protocol for the preparation of standardized PRP products. This impediment hinders widespread adoption by clinicians, particularly in endometrial or ovarian treatments. Drawing from evidence in other medical disciplines, this review endeavors to compile essential characteristics that PRPs must possess, aiming to mitigate the impact of variables affecting results in forthcoming studies.

Penetapan Biaya Standar Sebagai Pengendalian Biaya Produksi Pada Avos Coffee And Resto Medan

Avos Coffee and Resto Medan produces 1,000 cups of coffee every day with a predetermined sales target. However, this target is difficult to achieve and uncontrolled production costs can reduce profits, so control is needed. The aim of this research is to analyze the application of standard costs to control production costs at Avos Coffee and Resto Medan. This research is a descriptive qualitative research using data on actual production costs and standard production costs with one difference model deviation analysis calculations. Data collection techniques using observation, interviews and documentation. The results of this research show that the implementation of standard costs that has been carried out at Avos Coffee and Resto Medan is not optimal, this is because the main indicators are raw material costs, direct labor costs and factory overhead costs which are quite optimal. However, there were adverse deviations in raw material costs caused by price increases in December, causing them to be less than optimal, while direct labor costs and factory overhead costs were in a fairly optimal condition. Even though it is not optimal and there are many obstacles experienced, Avos Coffee and Resto Medan is able to maintain its business and continue producing. So by implementing these standard costs, Avos Coffee and Resto Medan can maintain its consistency and become better in the future.

Maximizing the Volume of Collocated Data from Two Coordinated Suborbital Platforms

Abstract Suborbital (e.g., airborne) campaigns that carry advanced remote sensing and in situ payloads provide detailed observations of atmospheric processes, but can be challenging to use when it is necessary to geographically collocate data from multiple platforms that make repeated observations of a given geographic location at different altitudes. This study reports on a data collocation algorithm that maximizes the volume of collocated data from two coordinated suborbital platforms and demonstrates its value using data from the NASA Aerosol Cloud Meteorology Interactions Over the western Atlantic Experiment (ACTIVATE) suborbital mission. A robust data collocation algorithm is critical for the success of the ACTIVATE mission goal to develop new and improved remote sensing algorithms, and quantify their performance. We demonstrate the value of these collocated data to quantify the performance of a recently developed vertically resolved lidar + polarimeter–derived aerosol particle number concentration (Na) product, resulting in a range-normalized mean absolute deviation (NMAD) of 9% compared to in situ measurements. We also show that this collocation algorithm increases the volume of collocated ACTIVATE data by 21% compared to using only nearest-neighbor finding algorithms alone. Additional to the benefits demonstrated within this study, the data files and routines produced by this algorithm have solved both the critical collocation and the collocation application steps for researchers who require collocated data for their own studies. This freely available and open-source collocation algorithm can be applied to future suborbital campaigns that, like ACTIVATE, use multiple platforms to conduct coordinated observations, e.g., a remote sensing aircraft together with in situ data collected from suborbital platforms. Significance Statement This study describes a data collocation (i.e., selection) process that aims to maximize the volume of data identified to be simultaneously collected in time and space from two coordinated measurement platforms. The functional utility of the resultant dataset is also demonstrated by extending the validation of aerosol particle number concentration derived from standard lidar and polarimeter data products from a suborbital mission that used two aircraft platforms.

The eROSITA upper limits

Context. The soft X-ray instrument eROSITA on board the Spectrum-Roentgen-Gamma (SRG) observatory has successfully completed four of the eight planned all-sky surveys, detecting almost one million X-ray sources during the first survey (eRASS1). The catalog of this survey will be released as part of the first eROSITA data release (DR1). Aims. Based on X-ray aperture photometry, we provide flux upper limits for eRASS1 in several energy bands. We cover galactic longitudes between 180° ≲ l ≲ 360° (eROSITA-DE). These data are crucial for studying the X-ray properties of variable and transient objects, as well as non-detected sources in the eROSITA all-sky survey data. Methods. We performed aperture photometry on every pixel of the SRG/eROSITA standard pipeline data products for all available sky tiles in the single detection band (0.2–2.3 keV). Simultaneously, we performed the same analysis in the three-band detection at soft (0.2–0.6 keV), medium (0.6–2.3 keV), and hard (2.3–5.0 keV) energy bands. Based on the combination of products for the individual bands, we are also able to provide aperture photometry products and flux upper limits for the 0.2–5.0 keV energy band. The upper limits were calculated based on a Bayesian approach that utilizes detected counts and background within the circular aperture. Results. The final data products consist of tables with the aperture photometry products (detected counts, background counts, and exposure time), a close-neighbor flag, and the upper flux limit based on an absorbed power-law spectral model (Γ = 2.0, NH = 3 × 1020 cm−2). The upper limits are calculated using the one-sided 3σ confidence interval (CL) of a normal distribution, representing CL = 99.87%. The aperture photometry products allow for an easy computation of upper limits at any other confidence interval and spectral model. These data are stored in a database with hierarchical indexes in order to offer a fast query option. Conclusions. We provide a detailed description of the process of retrieving SRG/eROSITA upper limits for a large set of input positions, as well as of the eROSITA data, the X-ray aperture photometry, the upper limit calculation, and the final data products. The eROSITA upper flux limits represent either the maximum flux of potential non-detections or the 3σ upper flux uncertainty of detected sources. We emphasize the importance of choosing the right spectral model that ought to match the spectral shape of the source of interest: the wrong spectral model can produce discrepancies of up to 30% in the final flux upper limit value. We also describe the architecture of the database and the web tool, which are designed to handle large queries on input positions.

Optimization of enterprises' costs for the purchase of energy resources and assessment of the economic feasibility of purchasing forwards for natural gas

The article is devoted to analyzing the energy market of Ukraine to introduce innovative approaches to reduce the costs of non-household consumers. The main problems of the functioning of the natural gas market of Ukraine, related to the organizational mechanism of trade in short-term and long-term standardized products under defined conditions, are considered. It is noted that the active development of gas exchange trade in Ukraine, which was taking place, is complicated by the problems of supply and gas in war conditions and the generalized advantages and disadvantages of options for purchasing natural gas for non-household consumers. The work states that natural gas consumers, regardless of the gas purchase scheme, are faced with the problem of a local rapid increase in the price of energy carriers. This leads to a decrease in business margins and a threat to the sustainable development of the enterprise. Based on the existing legislation in Ukraine and the organizational mechanism for regulating energy markets, a mechanism for fixing the price of natural gas in Ukraine for enterprises is proposed by purchasing volumes of natural gas in the period of lowest consumption and selecting it in the required period. An economic evaluation of the expediency of fixing the price of natural gas in order to reduce the costs of energy resources was carried out. A decrease in natural gas costs to non-domestic consumers when the price is fixed in the period of the lowest consumption has been demonstrated. The assessment showed that the volume of purchases significantly affects the overall efficiency. It is noted that the following points require further research: determination of periods of stable low prices and their duration, as well as the impact of the cost of using the funds involved in the purchase of natural gas. A proposed strategy for purchasing natural gas using forward and futures contracts, when enterprises can ensure stable and predictable gas supply conditions, contributes to effective cost management and business planning. Keywords: natural gas, optimal strategy, markets of exhaustible resources, energy market, demand for resources, supply of resources.