Low Price Research Articles

The Sustainable Development Trend, Progress and Challenge of Solar Cells

The current development of solar cells indicates that this field is experiencing rapid technological progress and market expansion. Various types of solar cells, from traditional silicon-based ones to emerging thin-film, dye-sensitized, perovskite, and organic solar cells, are constantly being developed to improve efficiency, reduce costs, and meet different application needs. While silicon-based solar cells remain one of the most mainstream types on the market, researchers are exploring third-generation photovoltaic devices such as multi-junction series cells, intermediate band gap cells, multiple exciton-generating cells hot carrier cells thermal-light photovoltaic solar cells to further bolster efficiency and reduce costs. These new solar cell technologies theoretically offer higher conversion efficiency and are anticipated to replace traditional silicon-based ones in the future. Advancements in the technology of solar cells mainly involve continuous progress and innovation in materials' development structural design manufacturing processes-from early silicon-based designs to today's thin-film arrays. Each generation is developed with the goal improving efficiency lowering costs; subsequently leading to recent developments in organic and perovskite arrays currently under exploration creating a final product at a lower price. At present, current attention within development primarily lies towards material components advancement efficiency maximization. Cost reduction strategies large scale production Although faced with certain obstacles; through consistent research proving their overwhelming effectiveness; implications for widespread use suggest performance. Overall prospects within Solar energy appear limitless.

The performance of alternative GPS tracking devices: a case report on wild boars (Sus scrofa)

BackgroundTelemetry studies on terrestrial mammals have been carried out almost exclusively using neck collar-mounted devices. However, collars are not suitable for all species and all age classes and may therefore compromise animal welfare and data quality requirements. Here, we evaluate the use of non-collar tracking devices on wild boars (Sus scrofa), a species for which collars may be problematic due to neck shape and seasonal body mass variation. We tested pelt-glued tags and three types of GPS ear tags. In addition, animals were marked with plain cattle ear tags.ResultsThe tested GPS tags exhibited various technical challenges related mostly to satellite coverage of the study area and tag loss. However, GPS devices enabled moderate movement monitoring of weeks to months, whereas plain cattle ear tags offered information on displacement over longer time intervals. The longest direct dispersal distance (163 km) by a wild boar sounder was discovered by cattle tags.ConclusionsData volume and quality obtained from small tags are inferior to data provided by GPS collars, but low-fix rate tags may enable monitoring of individuals with reduced invasiveness. Moreover, these tags enable tracking in cases where the collar is not an option. The low price and small size of the devices together with technical developments may offer cost-effective tools for future studies on dispersal and survival.

Identification of Bipolar Disorder and Schizophrenia Based on Brain CT and Deep Learning Methods.

With the increasing prevalence of mental illness, accurate clinical diagnosis of mental illness is crucial. Compared with MRI, CT has the advantages of wide application, low price, short scanning time, and high patient cooperation. This study aims to construct a deep learning (DL) model based on CT images to make identification of bipolar disorder (BD) and schizophrenia (SZ). A total of 506 patients (BD = 227, SZ = 279) and 179 healthy controls (HC) was collected from January 2022 to May 2023 at two hospitals, and divided into an internal training set and an internal validation set according to a ratio of 4:1. An additional 65 patients (BD = 35, SZ = 30) and 40 HC were recruited from different hospitals, and served as an external test set. All subjects accepted the conventional brain CT examination. The DenseMD model for identify BD and SZ using multiple instance learning was developed and compared with other classical DL models. The results showed that DenseMD performed excellently with an accuracy of 0.745 in the internal validation set, whereas the accuracy of the ResNet-18, ResNeXt-50, and DenseNet-121model was 0.672, 0.664, and 0.679, respectively. For the external test set, DenseMD again outperformed other models with an accuracy of 0.724; however, the accuracy of the ResNet-18, ResNeXt-50, and DenseNet-121model was 0.657, 0.638, and 0.676, respectively. Therefore, the potential of DL models for identification of BD and SZ based on brain CT images was established, and identification ability of the DenseMD model was better than other classical DL models.

Dynamic Luminescence Vapochromism of Pyridinium-Based Organic Salts.

Organic vapochromic materials which undergo a drastic change in their photophysical properties upon exposure to vapors or gases are attracting growing scientific attention because of their low price and wide range of possible applications. In this work, luminescence vapochromism of carbazole-pyridinium-based organic salts with a general structure of (CzPy)X (CzPy+ = 2,3-di(9H-carbazol-9-yl)pyridinium ion; X = Cl, Br or I) is reported. It was found that (CzPy)X compounds form J-aggregates, which rearranged back to monomeric form upon exposure to methanol, ethanol, acetone, and water vapors. In contrast, acetonitrile was found to promote the J-aggregation in (CzPy)X compounds by occupying the voids in their crystal lattice and pushing cations closer together. It was further demonstrated that the efficiency of J-aggregation in (CzPy)X compounds depends on the size of the anion, which was employed to realize dynamic luminescence vapochromism, with vapochromic response times ranging from a couple of minutes in (CzPy)Cl to more than an hour in (CzPy)I. In addition, (CzPy)X compounds exhibited high melting points of about 250 °C and excellent thermal stability. (CzPy)Cl and (CzPy)Br have also shown good photoluminescence quantum yields at room temperature in a solid state.

Synthesis of rice husk derived porous carbon as low-cost and high-performance electrode material for supercapacitors

Porous carbon electrode materials derived from agricultural by-products of food processing have attracted widespread interest. Rice husk (RH) is a promising raw material owing to its abundance and low price. In this study, a supercapacitor electrode was prepared by using recycled RH and secondarily activated with ZnCl2 to enhance its electrochemical energy storage performance. RH carbonized at the optimum temperature (i.e., 800 °C) was activated to synthesize RH-800-X (X = 1, 2, 3, 4, or 5, representing the mass ratio of ZnCl2 to RH-800). Sample RH-800-3 exhibited the highest specific surface area (1348.29 m2 g−1) and mesoporous pore volume (0.8375 cm3 g−1) among the samples. In a three-electrode system, the prepared electrodes delivered a high specific capacitance (242 F g−1 at 0.3 A g−1 in 6 M KOH solution). Furthermore, the capacitance retention of RH-800-3 remained at 99.9 % after 17,000 charge/discharge cycles. The results demonstrate the excellent capacitive behavior and superior electrochemical performance of RH-800-3. In addition, symmetrical capacitors prepared using RH-800-3 have an energy density of up to 101 Wh kg−1 at a power density of 900 W kg−1. Therefore, this study presents a simple and effective method for preparing a high-performance electrode material from biomass-derived porous carbon (i.e., recycled RH) and offers a new perspective for the efficient utilization of waste biomass resources.

Lifetime deals: the role of software service offering in convincing consumers

Purpose This study aims to reveal consumer purchase intentions for Software-as-a-Service (SaaS) lifetime deals and the role of service offerings in shaping these intentions. Design/methodology/approach Lifetime deals − an aggressive market penetration strategy − have the potential to allow startups to gain market share, user base and the cash necessary for growth. However, startups need to mitigate consumer concerns for which service offering design plays a key role. Drawing on expectancy-value and signaling theories, this study developed a research model and then conducted empirical research on 2,173 consumers via choice-based conjoint analysis to reveal the critical service offering attributes for consumer utility in lifetime deals in the SaaS presentation tool market context. After using the hierarchical Bayes model to derive each respondent’s part-worth utilities for service offering attributes, the hypotheses were tested via the factor score regression method. Findings The results show that the service offering attributes of low price, refund option, human support and feature updates enhance consumer utility in SaaS lifetime deals. Three of these four attributes, namely, low price, refund option and feature updates, enhance consumers' purchase intentions by reducing their concerns about the service’s performance, seller and lifespan, respectively. Originality/value This study elucidates consumer purchase intentions for SaaS services in digital marketplaces. By investigating a widespread market entry strategy − lifetime deals − it shows consumer preferences and behavior for these deals in the fast-growing online tools market. This study also shows how startups can use lifetime deals through a well-designed service offering to mitigate various consumer concerns.

Iron-decorated N/S co-doped porous carbon for sodium-ion battery anode to achieve high initial coulombic efficiency

Hard carbon materials are preferred as anode materials for sodium-ion batteries due to their abundance, low price, and environmental friendliness. However, doping-based modification usually induces low initial coulombic efficiency (ICE), which seriously affects the practical application of carbon materials. In this work, Fe-modified N/S co-doped porous carbon is prepared using the salt template method. Fe, N, and S are uniformly distributed on the porous carbon to form an interwoven network structure, providing abundant active sites. Moreover, during the electrochemical reaction, FeNx effectively catalyzes the generation of solid electrolyte interface (SEI) film, which reduces the consumption of Na+ in the side reaction, leading to a high initial coulombic efficiency, and at the same time, the stabilized SEI film accelerates the diffusion of electrons and ions, effectively enhancing the multiplication rate performance. The NFSC exhibits a high specific capacity (371.3 mAh/g) by the co-coordination strategy and a high ICE (85.9 %). This study provides new ideas for research based on the modification of carbon materials.

Interlayer substitution enables air-stable and long-life O3-type cathode for sodium-ion batteries

The O3-type oxides (NaNi0.4Fe0.2Mn0.4O2 (NFM)) have been considered as the most commercially cathode material for high-energy-density sodium-ion batteries owing to their low price, good safety performance, and high energy density. However, their further development is seriously limited due to the complex phase transition, sluggish kinetics of Na+, and intrinsic air instability. Herein, an interlayer substituted NFM (IS-NFM) is constructed by a simple solid-state method with the introduction of alkaline-earth metal. The interlayer substitution will lead to the increase of oxygen content in the internal lattice, which will effectively suppress the irreversible phase transition during cycling and exposure to the air. In addition, the interlayer substitution effectively activated the charge compensation, leading to the mobilized cationic redox process and boosted de-/sodiated kinetic. Consequently, IS-NFM exhibits excellent capacity retention of 83.44 % at 1 C after 200 cycles and remarkable stability even at high voltage. After 15 days of exposure to the air, IS-NFM also delivers superior capacity retention (86.53 %, compared with 0.1 C) and cycling performance (82.70 % at 1 C after 200 cycles). Undoubtedly, the interlayer substitution strategy will expand a novel avenue for constructing air-stable and long-life O3-type oxides for commercial application.

New Pipeline for Analysing Fruit Proteolytic Products Used as Digestive Health Nutraceuticals

Proteolytic products are extensively used in the nutraceutical sector to improve protein digestion and muscle quality in target populations (e.g., athletes or elderly). These products are processed using techniques that often lead to low purity but competitive pricing. Despite their widespread use and well-established production methods, the industry lacks standardized analytical methods for assessing these products and detecting potential fraud. This study proposes a comprehensive and harmonized pipeline for their analysis, which includes quantifying total soluble protein and proteolytic activity, as well as the determination of product stability and protein profile using SDS-PAGE and proteomic techniques. Despite the fact that protease extracts from pineapple had the highest protein content, most of the bromelain remained inactive, unlike in kiwi and papaya. SDS-PAGE revealed partial protein degradation of pineapple extracts, whereas kiwi extracts reflected a lower purification level but a higher protein integrity. The application of proteomic approaches strengthened the identification and origin tracing of the proteases. This study contributes to the development of a robust framework for analyzing proteolytic extracts, spanning from soluble protein quantification to protein profiling and activity determination. It may also ensure reliable supplier selection, high-quality manufacturing practices, and the implementation of optimal storage and formulation strategies in the nutraceutical industry.

A cost-minimization analysis of anti-VEGFs for the treatment of neovascular age-related macular degeneration in the Netherlands.

Age-related macular degeneration (AMD) is the main cause of severe vision loss globally. Neovascular AMD (nAMD) is an advanced stage of AMD treated with anti-vascular endothelial growth factors (anti-VEGFs). Although anti-VEGF treatment is effective, the frequent intravitreal injections place a burden on patients, (in)formal caregivers, and clinics. This study assesses the health-economic impact of anti-VEGF agents with lower injection frequency that have the potential to reduce treatment burden and compares it to the standard of care. We developed a cost-minimization model to evaluate the direct medical costs associated with first-line unilateral anti-VEGF treatment across a 3-year time horizon in the Netherlands. The analysis compared aflibercept 8mg, aflibercept 2mg, bevacizumab, faricimab, and ranibizumab. Our model adopted a treat-and-extend (T&E) regimen for aflibercept 2mg, bevacizumab, and ranibizumab. For aflibercept 8mg, a flexible regimen that was extendable up to 24weeks was applied, while faricimab followed a flexible regimen that was extendable up to 16weeks. Additionally, since list prices may vary from net prices, we calculated the break-even price for each anti-VEGF in comparison to bevacizumab, which is the recommended first-line treatment due to its low medication price. Based on list prices, aflibercept 8mg led to the lowest treatment costs (€16,251 per patient over a 3-year time horizon), closely followed by bevacizumab (€17,616 per patient over a 3-year time horizon). Ranibizumab led to the highest per-patient costs (€31,746 over a 3-year time horizon). For bevacizumab, most costs were attributable to administration, while for the other anti-VEGFs, most were attributable to medication. Aflibercept 8mg is cost-saving compared to bevacizumab at their medication prices at the time of writing. Aflibercept 2mg, faricimab, and ranibizumab should be priced below €488, €591, and €75, respectively. To be cost-equal to bevacizumab with current list prices, anti-VEGFs should be administered with a maximum of 12.7 to 13.8 injections over a 3-year time horizon. According to the injection frequency observed in clinical trials, aflibercept 8mg would be the anti-VEGF that generates the lowest per-patient healthcare costs for the treatment of nAMD in the Netherlands after a treatment period of three years. Our study indicates that anti-VEGF drugs with a lower injection frequency might provide a cost-saving solution to the increasing burden of anti-VEGF treatment on the healthcare system.

Natural Products and Derivatives as Japanese encephalitis virus antivirals.

Japanese encephalitis virus (JEV) causes acute Japanese encephalitis (JE) in humans and reproductive disorders in pigs. There are approximately 68,000 cases of JE worldwide each year, with approximately 13,600 to 20,400 deaths. JE infections have a fatality rate of one-third, and half of the survivors experience permanent neurological sequelae. The disease is prevalent throughout the Asia-Pacific region and has the potential to spread globally. JEV poses a serious threat to human life and health, and vaccination is currently the only strategy for long-term sustainable protection against JEV infection. However, licensed JEV vaccines are not effective against all strains of JEV. To date, there are no drugs approved for clinical use, and the development of anti-JEV drugs is urgently needed. Natural products are characterized by a wide range of sources, unique structures and low prices, and this paper provides an overview of the research and development of anti-JEV bioactive natural products.

Multicriteria selection practices in public tender evaluation process: the case of Sri Lanka

PurposeAwarding contracts based solely on the lowest price is unsuitable for every project. Consequently, most procurement systems in developed countries have progressed to the multicriteria selection practices (MSPs) for tender evaluation. MSPs consider a range of quality measures, such as completion time, life cycle cost, functional characteristics, environmental impact and innovation, alongside bid price. This study examines the prevailing MSPs in Sri Lankan public tender evaluations to enhance the effectiveness of the local tender evaluation process.Design/methodology/approachA desk study approach was employed to collect bidding documents, resulting in the identification of 66 documents. A systematic screening process was then applied to identify those bidding documents that incorporated MSPs. Subsequently, content analysis was conducted to determine the common features of the functions used in MSPs.FindingsThe study identified six primary functions related to MSPs incorporated in the bidding documents to procure building and substation projects. Three functions follow the price-to-quality method, while the remaining three follow the quality-to-price method. Among these identified functions, four functions employ objective evaluation criteria, such as thickness, capacity and operational loss. The other two functions utilize subjective evaluation criteria, such as the project’s design and technical specifications. Contract awarding will be based on either the highest score or the lowest bid, depending on the function type.Originality/valueThis study’s originality lies in exploring MSPs in the Sri Lankan public tender evaluation process and in disclosing their characteristics to promote the MSPs in Sri Lanka and developing countries.

The impact of gunfire on residential property values

ABSTRACT Hedonic studies of housing unit prices routinely attribute lower prices to perceived undesirable attributes and or amenities of the property sold. A steady stream of literature finds that criminal behaviour is negatively capitalized into housing unit prices. This study focuses on the effects of geocoded gunfire incidents on housing unit prices while controlling for other attributes and amenities at the census-block group level. The primary finding is that spatial and temporal proximity of gunfire incidents reduces housing unit prices in an analysis of 3,844 gunfire incidents, involving over 15,000 rounds of gunfire and 2,053 housing unit sales in Savannah, Georgia, from 2015 to 2020. The effect of gunfire is greater when it occurs in the immediate vicinity of the property. Heterogeneous effects on sale prices were found to be present across time and space when intensity was measured by the number of days with gunfire incidents and to a lesser extent when intensity was measured by the number of shots fired in each incident.

Co-Design of a Wind–Hydrogen System: The Effect of Varying Wind Turbine Types on Techno-Economic Parameters

Green hydrogen is crucial for achieving climate neutrality and replacing fossil fuels in processes that are hard to electrify. Wind farms producing electricity and hydrogen can help mitigate stress on electricity grids and enable new markets for operators. While optimizing wind farms for electricity production is well-established, optimizing combined wind–hydrogen systems is a relatively new research field. This study examines the potential profit of wind–hydrogen systems by conducting a case study of an onshore wind farm near the North Sea. Varying turbine types from high wind-speed turbines (with high annual energy production) to low wind-speed turbines (with high full-load hours) are examined. Findings indicate that in a combined hydrogen system, the low wind-speed turbines, which are sub-optimal for mere electricity production, yield lower levelized costs of hydrogen at a higher hydrogen production. Although high wind-speed turbines generate higher profits under current market conditions, at high hydrogen prices and low electricity prices, low wind-speed turbines can yield higher total profit at this site. Therefore, an integrated optimization approach of wind–hydrogen systems can, in certain cases, lead to better results compared to an isolated, sequential optimization of each individual system.

Minimum Space When Transporting Pigs: Where Is the "Good" Law?

This paper focuses on the problem of numeracy when writing regulations, specifically how to describe a threshold for crowding of pigs during transport, considering transported pigs range in body mass from 5 to 500 kg. When scientific findings provide the basis for regulation in the public interest, those findings must be communicated in a consistent way to regulators and policymaking bodies. Numeracy is the ability to understand, reason with, and apply appropriate numerical concepts to real-world questions. Scientific understanding is almost always based on rational understanding of numerical information, numeracy. The threshold of administrative offenses is often a numerical description. Commercial livestock transporters have an interest in loading livestock compartments to the maximum to achieve the largest payload allowed by axle weight laws, as is the case in all bulk commodity transport. Maximizing payload minimizes costs and environmental hazards of fuel exhaust and can benefit the public with lower pork prices, but has a serious animal welfare risk. Livestock production academics, veterinarians, and animal welfare activists have been working for decades to determine the level of livestock crowding in transport containers that would be appropriate for regulatory enforcement. The scientific discourse has been plagued by a lack of numerical standardization when describing results of trials and forming recommendations. Exceeding specific numerical thresholds is the core to implementing enforcement actions. This paper examines the communication and other barriers that have prevented emergence of a consensus on this question and provides a direction toward resolution. Further confirmation of effects of crowding livestock in transit is needed. This paper suggests that articulating an enforceable standard in pig transport is possible. In inspection for compliance, discovering the LP50 (lethal pressure-50) for slaughter-weight pigs is an initial global benchmark goal. The LP50 is the loading floor pressure in a commercial transport compartment, under field conditions, that would result in the death of at least one pig in the group 50% of the time.

ENSURING ECONOMIC SECURITY: COMPARISON OF EU MEMBER STATES AND UKRAINE

The purpose of this paper is to conduct a comprehensive study of economic security in the EU Member States and Ukraine, to identify differences and to propose targeted policy interventions based on these differences. Methodology. The study uses a quantitative strategy that assigns numerical ratings to countries based on their performance against predefined thresholds for various economic security indicators. These indicators include industrial security, demographic security, energy security, foreign trade security, investment and innovation security, macroeconomic security, food security, social security and financial security. The study uses data from a variety of sources and applies a ranking system to reflect the level of economic security in each category. Results. The analysis revealed significant differences in the levels of economic security between EU Member States and Ukraine. The main findings include differences in agricultural efficiency, healthcare system efficiency, renewable energy consumption, trade balance, research and development expenditure, and socio-economic factors. For example, countries such as Belgium and Ireland have high yields, while Cyprus and Romania have much lower yields. Life expectancy and the quality of healthcare also vary: Spain and Sweden lead the way, while Bulgaria and Ukraine lag behind. Practical implications. The findings suggest the need for targeted policies and technological advances to improve economic security. For the younger generation, marketing strategies based on brand equity and exclusivity can continue even during economic downturns. For the older generation, strategies that focus on value for money or lower prices may be more effective. Understanding these metrics can help businesses align their strategies with national economic priorities and identify potential areas for investment and growth. Value / Оriginality. This study contributes to the existing literature by providing a detailed comparative analysis of economic security in the EU Member States and Ukraine, filling a gap in the understanding of the multifaceted aspects of economic security in these regions.

Passenger car market and regional price discriminations for new cars: Case study and empirical analysis for Poland 2004–2021

Abstract Poland disposes on a large stock of mostly aged private passenger cars. In contrast younger cars still play minor role in individual mobility. The contribution analyzes reasons of lagging modernization by focusing on new cars prices with respect to regional price discrimination. It finds in 2004-2021 substantially increasing new cars prices and regional price discrimination between Poland and Germany. Price differentials were positive, with lower prices in Poland, and increased during time. Producers discriminated by prices increasingly but also limited arbitrage transactions by controlling excess differentials. Optimal regional price discrimination could support car markets developments in Poland by stock age compositions shifts towards younger cars. However, applied discrimination proves in observed market environments not sufficient to achieve a great car market transition in near future.

DeepInvesting: Stock market predictions with a sequence-oriented BiLSTM stacked model – A dataset case study of AMZN

Intelligent forecasters are now being considered in the stock market, providing essential insights and strategic guidance to investors and traders by presenting analytical tools and predictive models, thus enabling informed decision-making and mitigating financial risks in this dynamic market. The importance of intelligent analyzers in stock trading routines is considered in this work, where DeepInvesting, a multimodal deep learning model tailored for stock price prediction, is introduced. Employing a Sequence-Oriented, Long-Term Dependent (SoLTD) architecture featuring Bidirectional Long Short-Term Memory (BiLSTM) networks, DeepInvesting is applied to essential features of the Amazon Corp. (AMZN) market dataset, gathered from Yahoo Finance, including Closing, Opening, High, Low, Volume, and Adj Close prices. Exceptional performance in forecasting Closing, Opening, High, Low, and Adj Close prices is demonstrated, with minimal Mean Absolute Percentage Error (MAPE) and Root Mean Squared Percentage Error (RMSPE) scores, coupled with high R-squared (R2) values, manifesting a robust fit to the data, as well as computational complexity, and Rates Per Second (RPS) metrics in comparison to other models of KNN, LSTM, RNN, CNN, and ANN. Finally, challenges in the accurate prediction of trading volumes are identified, highlighting an area for future enhancement.

Onion (Allium cepa) Profit Maximization via Ensemble Learning-Based Framework for Efficient Nitrogen Fertilizer Use

Onion (Allium cepa) is a major field vegetable in South Korea and has been produced for a long time along with cabbage, radish, garlic, and dried peppers. However, as field vegetables, including onions, have recently been imported at low prices, the profitability of onion production in South Korea is beginning to be at risk. In order to maximize farmers’ profits through onion production, this study develops onion yield prediction models via an ensemble learning-based framework involving linear regression, polynomial regression, support vector regression, decision tree, ridge regression, and lasso regression. The use of nitrogen fertilizers is considered an independent variable in the development of the yield prediction model. This is because the use of nitrogen fertilizers accounts for the highest production cost (13.47%) after labor cost (41.21%) and seed cost (17.42%), and it also directly affects onions yields. For the model development, five research datasets on changes in onion yield according to changes in the use of existing nitrogen fertilizers were used. In addition, a non-linear optimization model was devised using onion yield prediction models for the profit maximization of onion production. As a result, the developed non-linear optimization model using polynomial regression enables an increase in profits from onion production by 67.28%.

Environmentally Friendly and Biodegradable Sodium Alginate-Based Biomembranes with Low Price and Enhanced Interfacial Compatibility

Environmentally Friendly and Biodegradable Sodium Alginate-Based Biomembranes with Low Price and Enhanced Interfacial Compatibility