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Purpose: Even though there is an immense level of research related to the impact of product quality and service quality on consumers’ purchase intentions the role of satisfaction as the mediator between perceived product qualities, affective commitment, and repurchase intentions has not been cross-examined in previous literature. To understand how this mediating mechanism affects repurchase intentions, we advanced a conceptual model. Design/Methodology/Approach: This study employed a quantitative research approach. Data were obtained using the convenience sampling method from a sample of 400 respondents. Statistical Package for the Social Sciences (SPSS) version 22.0 and Analysis of Moment Structure (AMOS) version 22.0 were used for the data analysis. Findings: Results show that the relationship between perceived product quality, affective commitment, and repurchase intentions is partially mediated by customers’ satisfaction. Implications/Originality/Value: understanding the underlying process of repurchase intentions of customers. The study is one of the exceptional efforts to provide evidence regarding the role of customer satisfaction as a mediating variable between independent and dependent variables.

Usually, polyphenols help address numerous health issues caused by oxidative stress. Tea is a popular beverage (rich in polyphenols) with abundant health promoting and disease prevention with great health-promoting and disease-prevention attributes, originating from the delicate, dried leaves of the Camellia sinensis plant. Tea has been proven to have health-boosting impacts like anti-inflammatory, anti-cancerous, anti-diabetic, and aids in weight loss. Cognitive impairment, also known as cognitive decline caused by aging or other neurological disorders, has become an emerging health concern. Tea polyphenols, especially phenolic acids, havegained enormous attention due to their link to improved cognitive function by preventing cognitive decline. This review summarizes recent studies on the health benefits of polyphenols in tea. Additionally, effective traditional and modern techniques to extract polyphenols and their effects on various diseases have been described.

The multimedia delivery chain consists of multiple stages such as content preparation, content delivery via Over-The-Top delivery network and Internet Service Providers network. Within the multimedia service chain, each stage influences the Quality of Experience (QoE) of the end user. The objective of this work is to provide a comprehensive literature survey with future research challenges and opportunities in the field of time-varying video quality in multimedia service delivery. The contribution of this work is two fold: 1) Survey – we provide a review of state-of-the-art works for video quality models to quantify multiple artifacts into a single QoE metric, pooling strategies for global quality measurements, and Continuous Time-Varying Quality (CTVQ) models; 2) Future Challenges and Directions – we investigate ten major research challenges and future directions based on the state-of-the-art for QoE modelling, QoE-aware encoding/decoding and QoE monitoring/management of multimedia streaming in next-generation networks.

Cancer is a severe condition characterized by uncontrolled cell division and increasing reported mortality and diagnostic cases. In 2040, an estimated 28.4 million cancer cases are expected to happen globally. In 2020, an estimated 19.3 million new cancer cases (18.1 million excluding non-melanoma skin cancer) had been diagnosed worldwide, with around 10.0 million cancer deaths. Breast cancer cases have increased by 2.26 million, lung cancer by 2.21 million, stomach by 1.089 million, liver by 0.96 million, and colon cancer by 1.93 million. Cancer is becoming more prevalent in Pakistan, with 19 million new cancer cases recorded in 2020. Food adulteration, gutkha, paan, and nutritional deficiencies are major cancer risk factors that interplay with cancer pathogenesis in this country. Government policies and legislation, cancer treatment challenges, and prevention must be revised seriously. This review presents the current cancer epidemiology in Pakistan to better understand cancer basis. It summarizes current cancer risk factors, causes, and the strategies and policies of the country against cancer.

Lately, the European Union has reinforced the targets set to cut back carbon emissions. The energy generation sector and particularly, the district heating (DH) system, is still prevailed by combustion of fossil fuels that heavily contributes to such emissions. This paper presents a system-based approach to study the coupling between electricity and DH sector for effective mitigation of emissions. A mixed integer linear programming framework is proposed that aims to exploit the flexibility of electricity cogeneration together with partial electrification of the DH system by investing in renewable technologies. The objective is to simultaneously minimize the investment cost and emissions. Both the electricity and DH load profiles are segregated into critical and flexible types. Comprehensive demand response (DR) framework of thermostatically controlled loads and electric vehicles is considered while preserving the chronology. The framework is applied to the Finnish energy system considering the generation mix. Results prove that coordinating the electricity cogeneration with renewable generation combined with partly shifting from DH to electrified heating has a great potential in reducing the emissions. For an average weather scenario under DR, the least-cost solution guarantees an annual emission reduction of 12.04% relative to the total emissions of Finland against the total investment of €13.24Bn in wind and solar power generation.

This paper proposes a Stackelberg game approach to minimize both the wind power imbalances and carbon emissions by harnessing demand response (DR) of residential heating loads fed by electricity or district heating (DH) options. The problem is formulated as a bilevel optimization model. An aggregator (leader) at the upper level aims at minimizing the mismatch between electricity demand and wind power while mitigating the carbon emissions arising from the DH system. The aggregator owns a wind farm and is responsible for controlling the DH generation through a combustion-based source and a deep well heat pump system (DWHP), which converts power into heat by utilizing wind power and replacing combustion-based DH. The aggregator submits bonuses to the households (followers) at the lower level incentivizing them to modify their consumption profile. The households receive the bonus offers and consequently decide how to optimize their net electricity and DH energy payments via an upward or downward DR strategy. The uncertainties associated with wind power and heating loads are considered using a stochastic programming framework. Long term thermal performance of the DWHP is studied separately. Results prove that the proposed bilevel framework enables significant reductions in wind power imbalances, carbon emissions, and energy payments.

Over the years, groundwater has been used as a means of adaptation to the seasonal and perennial scarcity of surface water. Groundwater provides water for households, livestock, and irrigation in semi-arid areas of Tanzania. It is acknowledged that groundwater is susceptible to chemical and other mineral contamination which not only poses a threat to the health of human beings and livestock but also agriculture. However, the potential of groundwater in terms of its viability and quality has not received adequate scrutiny from scholars. This paper provides a review of water quality and highlights the geogenic contamination of groundwater resources in Tanzania. The literature reviewed focused on the water resource sector in the major drainage basins of Tanzania, the information about drinking water quality with respect to geogenic contamination were sought. This paper has established that fluoride is the main and well-known groundwater contaminant. This is attributed to the existence of fluoride-rich minerals such as fluorite (CaF2), fluorapatite (Ca5(PO4)3F), cryolite (Na3AlF6), sellaite (MgF2), villiaumite (NaF), and topaz ((Al2(SiO4)F2), bastnaesite ((Ca, La, Nd)CO3F), and their ash deposits peeling from the granite and alkaline volcanic rocks, dominant in the region. The presence of fluoride in water sources in northern Tanzannia, part of the EARV contributes to the serious health effects on humans such as dental, skeletal, and crippling fluorosis. In addition, some literature indicated arsenic as a serious drinking water geogenic pollutant in the north-west parts of Tanzania. They pointed out that oxidation of arsenopyrite minerals is responsible for the dissolution and release of arsenic into groundwater. From this review we conclude that information on geochemistry/hydro-geochemistry of fluoride and arsenic in the aquifers is far inadequate and recommends that more research and development (R&D) efforts from scholars, researchers, and government institutions should be invested for further investigations and solutions. The focus should be creating awareness about the danger of using arsenic and fluoride contaminated water and development of affordable and environmental friendly water purification technologies.

Increased concern has recently emerged pertaining to the occurrence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aquatic environment during the current coronavirus disease 2019 (COVID-19) pandemic. While infectious SARS-CoV-2 has yet to be identified in the aquatic environment, the virus potentially enters the wastewater stream from patient excretions and a precautionary approach dictates evaluating transmission pathways to ensure public health and safety. Although enveloped viruses have presumed low persistence in water and are generally susceptible to inactivation by environmental stressors, previously identified enveloped viruses persist in the aqueous environment from days to several weeks. Our analysis suggests that not only the surface water, but also groundwater, represent SARS-CoV-2 control points through possible leaching and infiltrations of effluents from health care facilities, sewage, and drainage water. Most fecally transmitted viruses are highly persistent in the aquatic environment, and therefore, the persistence of SARS-CoV-2 in water is essential to inform its fate in water, wastewater and groundwater and subsequent human exposure.

Biodiesel is one of the potential alternative energy sources that can be derived from renewable and low-grade origin through different processes. One of the processes is alcoholysis or transesterification in the presence of a suitable catalyst. The catalyst can be either homogeneous or heterogeneous. This article reviews various catalysts used for biodiesel production to date, presents the state of the art of types of catalysts, and compares their suitability and associated challenges in the transesterification process. Biodiesel production using homogeneous and heterogeneous catalysis has been studied extensively, and novel heterogeneous catalysts are being continuously investigated. Homogeneous catalysts are generally efficient in converting biodiesel with low free fatty acid (FFA) and water containing single-origin feedstock. Heterogeneous catalysts, on the other hand, provide superior activity, range of selectivity, good FFA, and water adaptability. The quantity and strengths of active acid or basic sites control these properties. Some of the heterogeneous catalysts such as zirconia and zeolite-based catalysts can be used as both basic and acidic catalyst by suitable alteration. Heterogeneous catalysts from waste and biocatalysts play an essential role in attaining a sustainable alternative to traditional homogeneous catalysts for biodiesel production. Recently, high catalytic efficiency at mild operating conditions has drawn attention to nanocatalysts. This review evaluates state of the art and perspectives for catalytic biodiesel production and assesses the critical operational variables that influence biodiesel production along with the technological solutions for sustainable implementation of the process.

Arsenic (As) is a highly toxic element which naturally occurs in drinking water. In spite of substantial evidence on the association between many illnesses and chronic consumption of As, there is still a considerable uncertainty about the health risks due to low As concentrations in drinking water. In the Netherlands, drinking water companies aim to supply water with As concentration of

Increase velocity in omnidirectional (INVELOX) is the wind power transporting system, which is suitable for providing the maximum wind energy for better maneuver of wind turbine. This venturi has innovative features that are accomplished for functioning the integrating multiple wind turbine generator system, capture the wind flow through the omnidirectional intake and speed-ups the flow across the venturi region that is release into ambient environment through diffuser. In this study, INVELOX model 1 and model 2 are designed for investigation of pressure and velocity contours. Power output of turbine depends on pressure and velocity of wind. The venturi section result specifies velocity and pressure drop of both models of INVELOX; velocity of model 1 and model 2 increases from 10.42 to 45.5 m/s, respectively. Pressure drops transpire in model 1 and model 2 which decrease from − 1 . 722 × 10 1 and − 6 . 938 × 10 2 Pa , respectively. Upstream velocities and power of wind after throat of venturi are deliberated. The second and third turbines provide the less potential as compare to first turbine power. It is concluded that the power produced using multistage wind turbine is higher.

To achieve a successful integration of fluctuating renewable power generation, the power-to-heat (P2H) conversion is seen as an efficient solution that remedies the issue of curtailments as well as reduces carbon emissions prevailing in the district heating (DH) sector. Concurrently, the need for storage is also increasing to maintain a continuous power supply. Hence, this paper presents a MILP-based model to optimize the size of thermal storage required to satisfy the annual DH demand of a community solely by P2H conversion employing renewable energy. The DH is supplied by the optimal operation of a novel 2-km deep well heat pump system (DWHP) equipped with thermal storage. To avoid computational intractability, representative time steps with varying time duration are chosen by employing hierarchical agglomerative clustering that aggregates adjacent hours chronologically. The value of demand response and the effect of interannual weather variability are also analyzed. Numerical results from a Finnish case study show that P2H conversion utilizing small thermal storage in tandem with the DWHP is able to cover the annual DH demand, thus leading to a carbon-neutral DH system and, at the same time, mitigating the curtailment of excessive wind generation. Compared with the annual DH demand, an average thermal storage size of 29.17 MWh (2.58%) and 13.99 MWh (1.24%) are required in the business-as-usual and the demand response cases, respectively.

Current energy policy-driven targets have led to increasing deployment of renewable energy sources in electrical grids. However, due to the limited flexibility of current power systems, the rapidly growing number of installations of renewable energy systems has resulted in rising levels of generation curtailments. This paper probes the benefits of simultaneously coordinating aggregated hydro-reservoir storage with residential demand response (DR) for mitigating both load and generation curtailments in highly renewable generation power systems. DR services are provided by electric water heaters, thermal storages, electric vehicles, and heating, ventilation and air-conditioning (HVAC) loads. Accordingly, an optimization model is presented to minimize the mismatch between demand and supply in the Finnish power system. The model considers proportions of base-load generation comprising nuclear, and combined heat and power (CHP) plants (both CHP-city and CHP-industry), as well as future penetration scenarios of solar and wind power that are constructed, reflecting the present generation structure in Finland. The findings show that DR coordinated with hydropower is an efficient curtailment mitigation tool given the uncertainty in renewable generation. A comprehensive sensitivity analysis is also carried out to depict how higher penetration can reduce carbon emissions from electricity co-generation in the near future.

Efficient utilization of renewable generation inside microgrids remains challenging. In most existing studies, the goal is to optimize the energy cost of microgrids by working in synergy with the main grid. This work aimed at maximizing the self-consumption of on-site photovoltaic (PV) generation using an electrical storage, as well as demand response solutions, in a building that was also capable of interacting with the main grid. Ten-minute resolution data were used to capture the temporal behavior of the weather. Extensive mathematical models were employed to estimate the demand for hot-water consumption, space cooling, and heating loads. The proposed framework is cast as mixed-integer linear programming model while minimizing the interaction with the grid. To evaluate the effectiveness of the proposed framework, it was applied to a typical Finnish household. Matching indices were used to evaluate the degree of overlap between generation and demand under different PV penetrations and storage capacities. Despite negative correlation of PV generation with Finnish seasonal consumption, a significant portion of demand can be satisfied solely with on-site PV generation during the spring and summer seasons.