Time Variation Research Articles

Minitab 20 and Python based-the forecasting of demand and optimal inventory of liquid aluminum sulfate supplies

In a company, inventory management is crucial due to the significant impact on various aspects of the business. Similarly, the Indonesian water supply company (PDAM) requires effective inventory management to ensure the supply of liquid aluminum sulfate chemicals. The probabilistic statistical inventory control (SIC) model is commonly used for inventory management. However, previous research on chemical inventory models in PDAMs often relied on simple linear regression to forecast demand data, which fails to capture the inherent volatility in demand. Therefore, this research aimed to predict demand data using the seasonal autoregressive integrated moving average (SARIMA) method and determine the optimal policy for supplying liquid aluminum sulfate chemicals. The results showed that the best demand forecasting model was SARIMA (2,1,2) (1,1,0)12 with a mean absolute percentage error (MAPE) value of 8.19%. The finding of the optimal inventory policy showed a safety stock value of 11,922.35 kg, a reorder point value of 49,511.20 kg, and an order quantity of 21,526.59 kg, leading to a total cost of IDR 11,132,034,145.45. The sensitivity test also showed that variations in lead time, price, μ, and σ parameters directly influence changes in total cost, reorder point, and safety stock. These calculations were conducted using Minitab and Python software.

A Resource Prediction Method For Air Traffic Cyber-Physical-Social System

Air traffic is exhibiting the characteristics of large flow, strong coupling, and high time variation. Therefore, the complex network of air traffic is more vulnerable to disturbances. When it is disturbed, the failure of some nodes spreads through dependency relationships in the network, resulting in cascade failure. In the event of a cascade failure, the network may quickly collapse until it is paralyzed, with widespread delays and flight cancellations. The current flow management and deployment methods still remain in the control-oriented stage, which is mainly completed by air traffic controls (ATCs), and lack of accurate flow adjustment and effective utilization of capacity. The whole air traffic system and its peripheral factors are intricate, so human and social factors must be integrated into the control and decision-making of the system. Considering engineering and social factors such as operation environment, social environment, personnel, rules, equipment, and information processing, we analyse the air traffic in a cyber-physical-social system (CPSS). To reflect the actual system behaviour rules, dynamic response, limit state, and so on, the corresponding computational experiment and comprehensive evaluation system are established. Based on neural networks and other technologies, a resource prediction scheme based on task demand is proposed for multi-dimensional resources such as airports, air routes, and ATC, to reduce the cost of system resource scheduling and improve resource utilization through resource prediction and adjustment. Finally, the accuracy of the proposed resource prediction algorithm is verified by theoretical analysis and simulation.

Free radical mechanisms of ammonium sulfate as intensively used industrial materials on suppressing organic pollutants

Organic free radicals are critical intermediates for the generation and inhibition of organic pollutants during industrial processes. Clarifying the free radical mechanism of pollutant inhibition is significant for their efficient control. Ammonium sulfate is intensively used in industrial materials to suppress organic pollutants. In this study, organic free radical intermediate species in metal-catalyzed reactions inhibited by ammonium sulfate were identified using continuous-wave electron paramagnetic resonance (EPR) spectroscopy, providing direct evidence for the free radical mechanisms of organic pollutants inhibition. The transverse (T2) and longitudinal (T1) relaxation time variations catalyzed by different metal catalysts in the presence of ammonium sulfate were compared using pulsed-wave EPR. Consequently, after the addition of ammonium sulfate, the observed increase in T2 suggests that ammonium sulfate leads to radical concentration reduction. A decrease in the T1 relaxation time suggests the enhanced interaction between organic radicals and metals, which is an obstacle to subsequent radical reactions. Therefore, ammonium sulfate dominantly changed the free radical intermediates species, concentrations, and their reactivity, and then inhibited the organic pollutants formations. The inhibition mechanisms of ammonium sulfate on metal-catalyzed pollutants were then proposed combining EPR analysis, X-ray characterization, and high-resolution mass spectrometry screening. As a result, (1) occupying the active sites of metal catalysis and (2) inhibiting free radical intermediates are the two main intrinsic inhibition mechanisms of ammonium sulfate. The findings provide new perspectives on the efficient inhibition of organic pollutants in industrial processes involving various metal catalysts.

Microwave Synthesis of Fluorescent Carbon Quantum dots from Araucaria Heterophylla Gum: Application in Drug Detection.

This study employed a green microwave synthesis technique to produce carbon quantum dots (CQDs) from araucaria heterophylla gum extract. The produced CQDs emit a distinct blue fluorescent light, contributing a remarkable quantum yield of 14.69%. Their average particle size measures at 1.62 ± 0.39nm. Furthermore, these CQDs demonstrate excellent water solubility and maintain high fluorescence stability despite ionic strength, pH and time variations. Moreover, we present here for the first time that the synthesized CQDs demonstrate a rapid, exceptionally sensitive, and discerning fluorescence quenching phenomenon (IFE) concerning Cefprozil (CPR). The fluorescent probe was sensitive and specific with good linear relationships for CPR in the 0-18 µM range. The limit of detection for relationships for CPR was 2.51 µM. This study provides novel opportunities for producing high-quality luminescent CQDs that meet the requirements for various biological and environmental applications.

How to Distinguish Nonexponentiality and Nonlinearity in Isothermal Structural Relaxation of Glass-Forming Materials.

The nonexponentiality and nonlinearity are two essential features of the structural relaxation in any glass-forming material, which seem to be inextricably bound together by the material time. It is shown that the temperature down-jump and up-jump experiments of the same magnitude ΔT = T0 - T to the same temperature T provide a clue for their separation. The isothermal structural relaxation can be quantified using the stabilization period on the logarithmic time scale log(tm/t0). It is described as the sum of the nonexponentiality term 1.181/ß and the nonlinearity term (σ/2.303)ΔT for the temperature down-jump, and as their difference for the temperature up-jump. The material parameter σ = -(∂lnτ/∂Tf)i quantifies variation of the relaxation time with structural changes at the inflection point of the relaxation curve and is formulated for the most widely used phenomenological models. The asymmetry of approach to equilibrium after the temperature down-jump and up-jump was first described by Kovacs in 1963. A detailed analysis of this asymmetry is provided, and a simple method for the estimation of the parameters characterizing the nonexponentiality (ß) and nonlinearity (σ) is proposed. The applicability of this method is tested using previously reported isothermal experimental data as well as calculated data for aging of polymers and other glass-forming materials. This concept illuminates differences in structural relaxation kinetics in a simple and consistent way that can be useful in the design of novel materials and the evaluation of their physical aging treatment.

Investigation of the spatial variation of ambient air VOCs and their effects on the health risk caused by long-term exposure in urban area

ABSTRACT Long-term exposure to Volatile Organic Compounds (VOCs) is a health risk for citizens. In this study, the cumulative health risk of exposure to VOCs in Tehran was assessed by investigating the concentration of these pollutants in ambient air in a five-year period. Health risk assessment was calculated by the quantitative method and the carcinogenic risk level was determined using the lifetime carcinogenic risk (LCR) method. The average concentration of benzene, toluene, ortho-xylene, and ethylbenzene was 1.4–1.8, 4.8–5.4, 5–6.5, and 3.6–4 ppb, respectively. Although HQ was not greater than 1, but it was very close in the case of benzene, ortho-xylene, meta-xylene, and para-xylene. Benzene and ethylbenzene had the largest effect in the assessed health risk. So the long-term exposure of Tehran citizens to VOCs has serious health consequences for them, which could be different according to the exposure time and spatial variations.

Optimisation of TiO2 synthesis from ilmenite sand and its application in the photocatalytic process

ABSTRACT Iron sand, a mineral, can be extracted to produce titanium dioxide (TiO2). TiO2 is a semiconductor material that is commonly used in photocatalytic applications, as well as electronics, colour pigments, paint manufacturing, and semiconductors. In this study, TiO2 was extracted from Banten ilmenite sand using caustic fusion and hydrometallurgical methods. The TiO2 extraction process was carried out by varying the mole ratio of ilmenite sand to NaOH, which was 1:0, 1:3, and 1:5, and the fusion temperatures were 700°C and 850°C, with time variations of 30, 60, and 90 min. XRF analysis revealed that the highest TiO2 composition was 91.64% in samples with a mole ratio of 1:3 during 30 min of fusion time and 91.14% in samples with a mole ratio of 1:5 during 90 min of fusion time. The XRD data revealed that TiO2 has a rutile phase with a tetragonal structure, while scanning electron microscopy (SEM) analysis revealed that the particle distribution in the sample is not uniform. The UV-Vis measurements revealed that TiO2 has a band gap of 3.10 at 700°C and 3.13 at 850°C. Furthermore, TiO2 degraded Rhodamine B dyes at a rate of 28.266%.

Environmental impact assessment of horse and mechanical traction for vineyard cultivation

In the European Union, energy consumption in agriculture and forestry is less intense than in other economic sectors. However, fossil and non-renewable sources, particularly oil, are predominant, with higher percentages than in different economic sectors. In this context, this study aims to compare the environmental impact generated by equine and mechanical traction for viticulture practices in an organic production context, using life cycle assessment (LCA). Three scenarios were considered: business as usual (i.e., tractor-grown grapes) and horse-grown grapes but with two feeding options (tractor-grown hay and horse-grown hay). The results show that the tractor-grown grape scenario has higher impacts in five impact categories whereas the horse-grown scenario shows higher Global Warming, and to a minor extent Land use. Specifically, the worst results of the control scenario are in the mid-point category of Inorganic Respiratory due to fuel use, which produces P M 2.5. Fuel use is also the cause of the highest environmental burdens in other categories such as terrestrial Ecotoxicity. A sensitive analysis of the results was performed considering the endpoint damage categories. The outcomes show that, in general, the impact of horses is quite stable even under potentially different conditions. Some categories (ecosystem quality, global impact) are only slightly affected by variation in growth time, while all other categories (human health, resources, climate change) experience greater variation.

Does host migration affect host-parasite interaction? Migrant birds harbor exclusive parasites but have similar roles in parasite-host networks.

Parasites comprise a substantial portion of global biodiversity and play critical roles in shaping ecosystems by modulating trophic networks and affecting their hosts' abundance and distribution. The dynamics of host migration introduce new complexity to these relationships. From the host perspective, migratory behavior can either act as a defense mechanism or augment exposure to a broader spectrum of pathogens. Conversely, for parasites, host migration represents a mechanism for their dispersion and an opportunity to infect new host species. This study investigates the complex interplay between migration and parasite-host interactions, focusing on the interaction between hosts and avian malaria and malaria-like parasites in the Brazilian Atlantic Rain Forest. We captured 1466 birds representing 70 different species, uncovering 322 infections with Plasmodium/Haemoproteus parasites. We observed variations in migration timing and fluctuations in host abundance across months. By comparing the observed patterns of interaction of migratory and non-migratory birds to patterns of interaction expected at random, we show that migration affects the roles hosts take in the parasite-host network. Interestingly, despite the fact migratory species hosted more exclusive and distinct parasites, migrants did not occupy central network positions, which are mostly occupied by resident birds. Overall, we highlight the role of resident birds as a key species within parasite-host communities and the high specialization among avian haemosporidians and their hosts.

Time to start disease modifying drugs for adults with seropositive rheumatoid arthritis: results of the first year of the national New Zealand Rheumatology Association (NZRA) audit.

This audit describes variation in the time from referral to starting disease modifying drug (DMARD) for people with newly diagnosed seropositive rheumatoid arthritis (RA), how frequently this was within the recommended 6 weeks and whether regional, service-level or patient-level factors were associated with this variation. Rheumatologists submitted data on new patients with a new diagnosis of rheumatoid factor and/or cyclic-citrullinated peptide antibody positive RA. The association between visit funding, ethnicity, socio-economic deprivation, rurality, local specialist staffing levels and the time to DMARD treatment was assessed using Cox proportional-hazard models. Data were collected on 355 patients over 12 months. Overall, 64.8% of patients commenced DMARD treatment within 6 weeks of referral and this was associated with rheumatologist FTE per 100,000 population (adjusted HR 2.47, 95%CI 1.27-4.81; p=0.008) and the rurality (Geographic Classification of Health [GCH]) of the patient (for R2 compared to U1 adjusted HR 0.20, 95%CI 0.09-0.43; p<0.001). There was no association between time to DMARD and ethnicity or socio-economic deprivation. There was significant variation in time to DMARD treatment, mainly related to variation in rheumatologist staffing levels and patient rurality. Rheumatologist staffing levels of 1.0 FTE/100,000 population was associated with 80% of patients meeting the recommended 6-week time to DMARD treatment.

Screen viewing patterns and their association with mental wellbeing and psychological distress: a cross-sectional study amongst university students

BackgroundDependency on screen viewing (SV) has reached unprecedented levels, and mental health issues are becoming a major public health concern. However, the associations between SV, including variations in purposes, devices, and timing, and mental health remain unclear. This study aims to provide insights into these associations among university students.MethodsThis analysis used baseline data from a longitudinal cohort study among first-year university students matriculating in the 2021–2022 academic year. Self-reported data on sociodemographics, health behaviors and mental health outcomes alongside anthropometric measurements were collected. Unadjusted and adjusted logistic regression analyses were conducted.ResultsThe average age of the 997 valid students was 20.2 years, with 59.6% being female and 41.4% male. Students spent 14.3 h daily on SV, with females reporting higher SV than males. Daily SV was predominant for study purposes (7.6 h/day). Computer usage was the highest (7.0 h/day), while TV usage was the lowest (1.7 h/day). Poor mental wellbeing was reported by 33.6% of students, while 13.9% experienced psychological distress. Compared to students with low total SV, those with high levels were more likely to have poor mental wellbeing [OR (95% CI): 1.40 (0.99, 1.98)] and psychological distress [1.56 (1.00, 2.44)]. High levels of recreational and study related SV were significantly associated with poor mental wellbeing [1.81 (1.27, 2.56)] and psychological distress [1.75 (1.11, 2.83)], respectively. Those with high levels of computer time were more likely to have poor mental wellbeing [1.44 (1.01, 2.06)], and high weekend day SV was associated with greater odds of psychological distress [2.16 (1.17, 4.06)].ConclusionsSV among university students was high, as was the high prevalence of poor mental wellbeing and psychological distress. Greater SV was associated with poor mental wellbeing and psychological distress. Differences according to purpose of SV were noted. Although recreational SV was associated with poor mental wellbeing, study related SV was associated with psychological distress. Variations across different devices and timing were also noted. This highlights the need for further longitudinal research to understand the impact of SV on mental health and to guide interventions for promoting mental health of university students globally.

Variation in Times to Accessing Non-Invasive Testing Among Patients Managed Within a Nurse-Led Rapid Access Chest Pain Clinic, and Impact of COVID-19

Variation in Times to Accessing Non-Invasive Testing Among Patients Managed Within a Nurse-Led Rapid Access Chest Pain Clinic, and Impact of COVID-19

Inbreeding avoidance, competition and natal dispersal in a pair-living, genetically monogamous mammal, Azara's owl monkey (Aotus azarae).

Natal dispersal is an important life-history stage influencing individual fitness, social dynamics of groups and population structure. Understanding factors influencing dispersal is essential for evaluating explanations for the evolution and maintenance of social organization, including parental care and mating systems. The social and mating systems of Azara's owl monkeys (Aotus azarae) are infrequent among mammals; these primates are pair-living, serially and genetically monogamous and both sexes directly care for offspring. To evaluate the role that competition and inbreeding avoidance play in shaping dispersal patterns, we used 25 years of demographic and genetic data to examine how variation in timing of natal dispersal is related to social (adult replacements, step-parents, births and group size) and ecological factors (seasonal abundance of resources) in a wild population of A. azarae in Formosa, Argentina. We found that all males and females dispersed from their natal groups, but subadults delayed dispersal when a step-parent of the opposite sex joined the group, indicating that they may perceive these step-parents as potential mates. Dispersal was more probable when resource conditions were better, regardless of age. Overall, agonistic conflict over food and potential mates with adults in the natal group, as well as inbreeding avoidance, contribute to regulating dispersal.

Characterization of Position Synchronous Control System for Double Hydraulic Cylinder

Background: There are some problems in the synchronous control system of electrohydraulic servo double hydraulic cylinders, such as uncertainty of system parameters, time variation, difference between two subsystems, and unbalanced load disturbance during operation. The above problems cause the output responses of the two cylinders to be inconsistent, resulting in the situation that the output flows of the two cylinders are not synchronized. Objective: Further improve the accuracy of synchronous control while reducing the cost of using synchronous control system. Methods: The AMEsim simulation model of electro-hydraulic servo dual-cylinder synchronous control system is established, and based on this model, the dynamic characteristics, coupling characteristics, and synchronization characteristics of the double-cylinder system are analyzed theoretically and simulated. Results: Analyze and verify the influence of various factors on the synchronization of double hydraulic cylinders, and summarize the influence law of the change of different factors on the output and synchronization accuracy of the double hydraulic cylinder system. Conclusion: This study analyzes the influence of various factors on the synchronization of double cylinders by adjusting the parameters, and summarizes the influence law of the change of different factors on the output and synchronization accuracy of the double cylinder system.

Comparison of four ventilation tubes commonly used in the pediatric population: A retrospective cohort study.

To assess differences in otorrhea, tympanic membrane perforation, and time to extrusion in children receiving one of four commonly used, short-term ventilation tubes for the first time. Retrospective chart review of 2 years of postoperative follow-up to analyze patient outcomes after insertion of either a Paparella type-I Activent, Armstrong Beveled, Modified Armstrong, or Armstrong Microgel ventilation tube. Incidence of complications was determined by reviewing provider notes. Adjusted multivariate logistic regression models were used to determine odds ratios of complications among the four tube types. A total of 387 patients were reviewed. The mean age was 2.4 years and 35.9% were female. Armstrong beveled tubes had the highest odds of otorrhea. Paparella type-I tube had the shortest time to extrusion of about 9 months, while Armstrong Beveled had the longest, at almost 19 months. When evaluating episodes of otorrhea each child experienced on average, per month, Armstrong beveled tubes had the highest monthly rate of otorrhea and Paparella type-I the least. No significant differences were found regarding tympanic membrane perforation. This retrospective chart review showed that no tube was clinically superior across all complications. The findings from this study may give otolaryngologists an opportunity to consider choosing a specific type of tube according to the clinical situation. The large variations in extrusion times should be considered in terms of patient age, seasonality, and desired duration of tube placement. 4.

Intensity, Characteristics, and Factors Associated With Receipt of Care Coordination Among High-Risk Veterans in the Veterans Health Administration.

The Veterans Health Administration (VHA) has initiatives underway to enhance the provision of care coordination (CC), particularly among high-risk Veterans. Yet, evidence detailing the characteristics of and who receives VHA CC is limited. We examined intensity, timing, setting, and factors associated with VHA CC among high-risk Veterans. We conducted a retrospective observational cohort study, following Veterans for 1 year after being identified as high-risk for hospitalization or mortality, to characterize their CC. Demographic and clinical factors predictive of CC were identified via multivariate logistic regression. A total of 1,843,272 VHA-enrolled high-risk Veterans in fiscal years 2019-2021. We measured 5 CC variables during the year after Veterans were identified as high risk: (1) receipt of any service, (2) number of services received, (3) number of days to first service, (4) number of days between services, and (5) type of visit during which services were received. Overall, 31% of high-risk Veterans in the sample received CC during one-year follow-up. Among Veterans who received ≥1 service, a median of 2 [IQR (1, 6)] services were received. Among Veterans who received ≥2 services, there was a median of 26 [IQR (10, 57)] days between services. Most services were received during outpatient psychiatry (46%) or medicine (16%) visits. Veterans' sociodemographic and clinical characteristics were associated with receipt of CC. A minority of Veterans received CC in the year after being identified as high-risk, and there was variation in intensity, timing, and setting of CC. Research is needed to examine the fit between Veterans' CC needs and preferences and VHA CC delivery.

The Effect of Fermentation Time Variation on Antioxidant Activity of Fermented Robusta Coffee Leaves (Coffea canephora Pierre ex A.Froehner) Brew

Antioxidants are electron-donor compounds that can delay, slow down and prevent free radical reactions. Fermentation is a chemical change that occurs due to the activity of microorganisms which can increase the amount of phenols in tea thereby increasing its antioxidant activity. Fermentation is carried out with the help of a Symbiotic Culture of Bacteria and Yeast (SCOBY) culture, which is commonly used in the production of kombucha. Kombucha is a fermented tea drink produced from leaves that contain high phenols such as robusta coffee leaves (Coffea canephora Pierre ex A.Froehner). Factors that affect the fermentation process are pH and fermentation time. This study aimed to explain the effect of fermentation time on the antioxidant activity of fermented robusta coffee leaves brew. Brewed robusta coffee leaves were made by brewing robusta coffee leaves simplicia powder, adding kombucha liquid starter, then fermented for 0; 3; 7; 14; and 21 days, then pH and antioxidant activity was measured using UV-Visible spectrophotometer using the 2,2-dipheny-1,1-picrylhydrazyl (DPPH) at a wavelength of 516 nm. This study showed that 0; 3; 7; 14; and 21 days fermented robusta coffee leaves brew have pH of 6,07; 4,62; 4,07; 3,21; and 2,74, and IC50 values is 285,1645 μg/ml; 219,7012 μg/ml; 192,2325 μg/ml; 187,0434 μg/ml; and 173,9249 µg/ml. There is an effect of fermentation time variation on the antioxidant activity of fermented robusta coffee leaves brew. Keyword: Antioxidant, Fermentation, pH, Robusta coffee leaves, Time variation

Subcritical water extraction of mangrove fruit extract (Sonneratia alba) and its antioxidant activity, network pharmacology, and molecular connectivity studies

Functional foods containing antioxidant molecules can limit the prevalence of various diseases, increase immunity, slow aging, and improve physical appearance. The aim of this study was to use non-toxic to prepare extracts from the Sonneratia alba fruit, determine the phytochemical composition, and assess the biological activity via in silico and in vitro antioxidant capability. Variations in temperatures and times showed that the conditions for best phytochemicals and antioxidant activity were 100 °C and 10 min. The highest values were 23.33 mg quercetin equivalent/g (flavonoids), 1.24 mg tannic acid equivalent/g (tannins), and IC50 = 62.38 ppm (antioxidant activity). Gas chromatography displayed 7 peaks that were attributed to 21 possible compounds. Molecular docking analysis results showed that the mechanism of three of the compounds (1) Ethyl iso-allocholate, (2) Gibb-3-ene-1,10-dicarboxylic acid,2,4a,7-trihydroxy-1-methyl-8-methylene-,1,4a-lactone,10-methyl ester,(1a,2β,4aa,4bβ,10β)-, and (3) Pregn-4-ene-3,20-dione,17,21-dihydroxy-,bis(O-methyloxime) could be due to their binding via hydrogen bonding to 3 reactive oxygen species (ROS) proteins (nitric oxide synthases). Subcritical water extract of Mangrove fruit (S. alba) has potential as a functional food that has antioxidant activity in silico and in vitro.

Factors Associated with Variation in Time in Therapeutic Range in Two Anticoagulation Clinics in Brazil

Factors Associated with Variation in Time in Therapeutic Range in Two Anticoagulation Clinics in Brazil

Temporal characteristics of a 6.2 Ma-long ash-fall history in the NW Pacific

Explosive volcanism is one of the most dangerous and far-reaching natural hazards. The largest eruptions are the rarest, so studies of their temporal patterns have to rely on long archives. In this paper, we apply fractal and spectral analyses to the 6.2 Ma-long record of ash-falls at the Detroit Seamount (DS6M), > 600 km east of the Kamchatka Peninsula, NW Pacific, combined with a terrestrial record for the last 30 ka (T30ka). These datasets are the most complete for volcanism in the North Pacific, and DS6M spans all Pleistocene glaciations. In both datasets, events are grouped (Weibull parameter k < 0.84) with no characteristic scale of grouping in the time domain of thousands to millions of years. The fractal dimension of the studied data below the unity may be intrinsic to the volcanism (e.g. as a proxy of fractal composition and topography of a subducting plate) or represent uneven deposition and recovery of tephra. Only for the last 700 ka of DS6M, an increase in the correlation dimension values suggests the applicability of spectral analysis; however, no Milankovitch frequencies have been detected in this dataset. When compared to other North Pacific data for areas repeatedly glaciated in the Middle and Late Pleistocene and to a climate proxy of 18O isotopic stack LR04, the studied data suggest that variation in timing of ash-falls among the sites predominates over hemispheric-scale climatic forcing. If so, Quaternary glaciations had a limited effect on the timing of large explosive eruptions in North Pacific, still affecting the transit and deposition of erupted material.