Application of advanced energy storage materials in direct solar desalination: A state of art review

Storage of the thermal energy of solar intensity has a significant effect on the efficiency of desalination systems at nighttime, when solar intensity is not available. Solar energy provides the potential to facilitate the freshwater needs of small communities, where access to potable water is commonly limited. However, freshwater generation formation via solar stills remains low when compared to other desalination methods. Hence, multiple innovative materials for efficient water production by solar stills have been invetsigated in the literature, where this is addressed on a wide scale in this comprehensive review. This includes a focus on innovative materials including nanomaterials, nanofluids, nanoparticles-based phase change materials (PCMs), composite PCMs, PCMs with porous materials and PCMs with heat pipes. The review\u27s outcomes identify that advanced energy storage materials substantially influence the enhancement of solar still productivity as compared to conventional solar stills. The results indicate that the application of thermosyphon heat pipes with PCM more than doubles the performance of solar still water productivity. The productivity of solar desalination can also be improved by utilizing PCM/porous materials, with results indicating solar still water productivity to be enhanced by between 40 and 70%. A cost analysis as well as an environmental evaluation of PCM-based solar desalination is also compiled in this review. A summary of the current status, leading groups, journals, and countries related to advanced energy storage materials in solar desalination is presented. Lastly, recommendations related to advanced energy storage materials in solar desalination are noted, assisting researchers to explore efficient water treatment methods

Role of E-commerce in Foreign Trade Promotion: Some Evidence from Pakistan

This study scrutinizes facts relating to the empirical relevance between e-commerce and foreign trade in Pakistan. For the purpose of analysis quarterly based time series data (1998Q1-2011Q4) was considered. Number of internet connections (proxy for e-commerce) was taken as exogenous variable. While foreign trade was endogenous variable of the model. Study empirically proves that with the increase in internet facility foreign trade has greatly increased. Key Words: E-commerce, foreign trade, internet connections, Pakistan

Passive cooling analysis of an electronic chipset using nanoparticles and metal-foam composite PCM: An experimental study

Thermal management of electronic components is critical for long-term reliability and continuous operation, as the over-heating of electronic equipment leads to decrement in performance. The novelty of the current experimental study is to investigate the passive cooling of electronic equipment, by using nano-enriched phase change material (NEPCM) with copper foam having porosity of 97 %. The phase change material of PT-58 was used with graphene nanoplatelets (GNPs) and magnesium oxide (MgO) nanoparticles (NPs), having concentrations of 0.01 wt. % and 0.02 wt. %. Three power levels of 8 W, 16 W, and 24 W, with corresponding heating inputs of 0.77 kW/ m2, 1.54 kW/ m2 and 2.3 kW/ m2, respectively, were used to simulate the heating input to heat sink for thermal characterization. According to results, at 0.77 kW/ m2 heating input the maximum base temperature declined by 13.03 % in 0.02 wt. % GNPs-NEPCM/copper foam case. At heating input of 1.54 kW/ m2, the maximum base temperature reduction of 16 % was observed in case of 0.02 wt. % GNPs-NEPCM/copper foam and 13.1 % in case of 0.02 wt. % MgO-NEPCM/copper foam. Similarly, at heating input of 2.3 kW/ m2, the maximum temperature of base lessened by 12.58 % in case of 0.02 wt. % GNPs-NEPCM/copper foam. The highest time to reach the set point temperature of 50 ⁰ C, 60 ⁰ C, and 70 ⁰ C was in case of GNPs-NEPCM/copper foam composites, while at all power levels MgO-NEPCM/copper foam gave comparable performance to GNPs based composite. Similar trend was observed in the study of enhancement ratio in operation time. From the results, it is concluded that the copper foam incorporation in NEPCM is an effective measure to mitigate the heat sink base temperature and can provide best cooling efficiency at low and higher heating loads

Evaluation of Energy Production and Energy Yield Assessment Based on Feasibility, Design, and Execution of 3 × 50 MW Grid-Connected Solar PV Pilot Project in Nooriabad

The installation of 3 × 50 MW (150 MW DC) large utility scale solar power plant is ground based using ventilated polycrystalline module technology with fixed tilt angle of 28° in a 750-acre land, and the site is located about 115 km northeast of Karachi, Pakistan, near the town of ThanoBula Khan, Nooriabad, Sindh. This plant will be connected to the utility distribution system through a national grid of 220 kV outgoing double-loop transmission line. The 3 × 50 MW solar PV will be one of the largest tied grid-connected power projects as the site is receiving a rich average solar radiation of 158.7 kW/h/m2/month and an annual average temperature of about of 27°C. The analysis highlights the preliminary design of the case project such as feasibility study and PV solar design aspects and is based on a simulation study of energy yield assessment which has all been illustrated. The annual energy production and energy yield assessment values of the plant are computed using the PVSYST software. The assumptions and results of energy losses, annual performance ratio (PR) 74.73%, annual capacity factor 17.7%, and annual energy production of the plant at 232,518 MWh/year are recorded accordingly. Bear in mind that reference recorded data indicates a good agreement over the performance of the proposed PV power plant

Passive Cooling Analysis of an Electronic Chipset Using Nanoparticles and Metal-Foam Composite PCM: An Experimental Study

Thermal management of electronic components is critical for long-term reliability and continuous operation, as the over-heating of electronic equipment leads to decrement in performance. The novelty of the current experimental study is to investigate the passive cooling of electronic equipment, by using nano-enriched phase change material (NEPCM) with copper foam having porosity of 97. The phase change material of PT-58 was used with graphene nanoplatelets (GNPs) and magnesium oxide (MgO) nanoparticles (NPs), having concentrations of 0.01 wt. and 0.02 wt.. Three power levels of 8 W, 16 W, and 24 W, with corresponding heating inputs of 0.77 kW/m2, 1.54 kW/m2 and 2.3 kW/m2, respectively, were used to simulate the heating input to heat sink for thermal characterization. According to results, at 0.77 kW/m2 heating input the maximum base temperature declined by 13.03 in 0.02 wt. GNPs-NEPCM/copper foam case. At heating input of 1.54 kW/m2, the maximum base temperature reduction of 16 was observed in case of 0.02 wt. GNPs-NEPCM/copper foam and 13.1 in case of 0.02 wt. MgO-NEPCM/copper foam. Similarly, at heating input of 2.3 kW/m2, the maximum temperature of base lessened by 12.58 in case of 0.02 wt. GNPs-NEPCM/copper foam. The highest time to reach the set point temperature of 50 °C, 60 °C, and 70 °C was in case of GNPs-NEPCM/copper foam composites, while at all power levels MgO-NEPCM/copper foam gave comparable performance to GNPs based composite. Similar trend was observed in the study of enhancement ratio in operation time. From the results, it is concluded that the copper foam incorporation in NEPCM is an effective measure to mitigate the heat sink base temperature and can provide best cooling efficiency at low and higher heating load

Pathobiome driven gut inflammation in Pakistani children with environmental enteric dysfunction

Environmental Enteric Dysfunction (EED) is an acquired small intestinal inflammatory condition underlying high rates of stunting in children \u3c5 years of age in low- and middle-income countries. Children with EED are known to have repeated exposures to enteropathogens and environmental toxins that leads to malabsorptive syndrome. We aimed to characterize association of linear growth faltering with enteropathogen burden and subsequent changes in EED biomarkers. In a longitudinal birth cohort (n = 272), monthly anthropometric measurements (Length for Age Z score- LAZ) of asymptomatic children were obtained up to 18 months. Biological samples were collected at 6 and 9 months for the assessment of biomarkers. A customized TaqMan array card was used to target 40 enteropathogens in fecal samples. Linear regression was applied to study the effect of specific enteropathogen infection on change in linear growth (ΔLAZ). Presence of any pathogen in fecal sample correlated with serum flagellin IgA (6 mo, r = 0.19, p = 0.002), fecal Reg 1b (6 mo, r = 0.16, p = 0.01; 9mo, r = 0.16, p = 0.008) and serum Reg 1b (6 mo, r = 0.26, p\u3c0.0001; 9 mo, r = 0.15, p = 0.008). At 6 months, presence of Campylobacter [β (SE) 7751.2 (2608.5), p = 0.003] and ETEC LT [β (SE) 7089.2 (3015.04), p = 0.019] was associated with increase in MPO. Giardia was associated with increase in Reg1b [β (SE) 72.189 (26.394), p = 0.006] and antiflic IgA[β (SE) 0.054 (0.021), p = 0.0091]. Multiple enteropathogen infections in early life negatively correlated with ΔLAZ, and simultaneous changes in gut inflammatory and permeability markers. A combination vaccine targeting enteropathogens in early life could help in the prevention of future stuntin

Gut integrity and duodenal enteropathogen burden in undernourished children with environmental enteric dysfunction

Environmental enteric dysfunction (EED) is a subclinical condition of intestinal inflammation, barrier dysfunction and malabsorption associated with growth faltering in children living in poverty. This study explores association of altered duodenal permeability (lactulose, rhamnose and their ratio) with higher burden of enteropathogen in the duodenal aspirate, altered histopathological findings and higher morbidity (diarrhea) that is collectively associated with linear growth faltering in children living in EED endemic setting. In a longitudinal birth cohort, 51 controls (WHZ \u3e 0, HAZ \u3e -1.0) and 63 cases (WHZ\u3c -2.0, refractory to nutritional intervention) were recruited. Anthropometry and morbidity were recorded on monthly bases up to 24 months of age. Dual sugar assay of urine collected after oral administration of lactulose and rhamnose was assessed in 96 children from both the groups. Duodenal histopathology (n = 63) and enteropathogen analysis of aspirate via Taqman array card (n = 60) was assessed in only cases. Giardia was the most frequent pathogen and was associated with raised L:R ratio (p = 0.068). Gastric microscopy was more sensitive than duodenal aspirate in H. pylori detection. Microscopically confirmed H. pylori negatively correlated with HAZ at 24 months (r = -0.313, p = 0.013). Regarding histopathological parameters, goblet cell reduction significantly correlated with decline in dual sugar excretion (p\u3c 0.05). Between cases and controls, there were no significant differences in the median (25th, 75th percentile) of urinary concentrations (μg/ml) of lactulose [27.0 (11.50, 59.50) for cases vs. 38.0 (12.0, 61.0) for controls], rhamnose [66.0 (28.0, 178.0) vs. 86.5 (29.5, 190.5)] and L:R ratio [0.47 (0.24, 0.90) vs. 0.51 (0.31, 0.71)] respectively. In multivariable regression model, 31% of variability in HAZ at 24 months of age among cases and controls was explained by final model including dual sugars. In conclusion, enteropathogen burden is associated with altered histopathological features and intestinal permeability. In cases and controls living in settings of endemic enteropathy, intestinal permeability test may predict linear growth. However, for adoption as a screening tool for EED, further validation is required due to its complex intestinal pathophysiology

Multisource Data Fusion Framework for Land Use/Land Cover Classification Using Machine Vision

Data fusion is a powerful tool for the merging of multiple sources of information to produce a better output as compared to individual source. This study describes the data fusion of five land use/cover types, that is, bare land, fertile cultivated land, desert rangeland, green pasture, and Sutlej basin river land derived from remote sensing. A novel framework for multispectral and texture feature based data fusion is designed to identify the land use/land cover data types correctly. Multispectral data is obtained using a multispectral radiometer, while digital camera is used for image dataset. It has been observed that each image contained 229 texture features, while 30 optimized texture features data for each image has been obtained by joining together three features selection techniques, that is, Fisher, Probability of Error plus Average Correlation, and Mutual Information. This 30-optimized-texture-feature dataset is merged with five-spectral-feature dataset to build the fused dataset. A comparison is performed among texture, multispectral, and fused dataset using machine vision classifiers. It has been observed that fused dataset outperformed individually both datasets. The overall accuracy acquired using multilayer perceptron for texture data, multispectral data, and fused data was 96.67%, 97.60%, and 99.60%, respectively

Syncope: experience at a tertiary care hospital in Karachi, Pakistan

Introduction:Our aim was to determine the characteristics of Patients presenting with syncope at a tertiary care hospital in Karachi, Pakistan.Methods: A review of medical records was conducted retrospectively at the Department of Medicine, Aga Khan University Hospital, Karachi. Patients aged 16 and above, admitted from January 2000 to December 2005 with the diagnosis of syncope made by the attending physician were included.Results:A total of 269 Patients were included (75% males, mean age: 57.4 years). Neurogenic (vasovagal) syncope was the most common cause (47%), followed by cardiogenic syncope (18%) and orthostatic syncope (9%). A total of 24% were discharged undiagnosed. Twenty Patients (7.4%) did not have any prodrome. Common prodromal symptoms included dizziness (61%), sweating (25%), palpitations (19%), nausea/vomiting (19%) and visual symptoms (17%). The distribution of symptoms according to cause of syncope revealed only breathlessness to be significantly associated with cardiogenic syncope (p = 0.002). Most Patients with cardiogenic syncope were aged above 40 (98%, p \u3c 0.001), had coronary artery disease (72%, p \u3c 0.001) and abnormal electrocardiogram at presentation (92%, p \u3c 0.001).Conclusion:Despite differences in burden of diseases, our findings were similar to those of published syncope literature. Further studies are needed to develop a protocol to expedite the evaluation and limit the work-up and admission in low-risk Patients

Uncertainty Analysis of Energy Production for a 3 × 50 MW AC Photovoltaic Project Based on Solar Resources

Access to solar energy is a prerequisite to remedy CO2 and improve the standard of human living. Green solar energy is only an immediate solution to add its zero emission profile and provide carbon footprint reduction benefits. This energy does not emit greenhouse gases which means it is a renewable free source of energy when producing electricity. The purpose of this paper is to investigate the accurate annul energy production data reducing uncertainty in solar energy estimates. This work investigated the solar energy assessment taking into account a detailed solar resource and energy production assessment for a 3 × 50 MW PV project with uncertainty analysis. The authors defined a total uncertainty of energy production which is estimated at 9.5% for one year and 8.9% for ten years as well as future variability of 3.4% for one year and 1.1% for ten years. The annual power degradation and expected energy production over the plant lifespan at dissimilar 99%, 90%, 75%, 60%, 50%, and 25% probability of surplus are also observed in this paper