Energy efficiency of a flat-plate solar collector using thermally treated graphene-based nanofluids: Experimental study

© The Author(s) 2020. A covalent functionalization approach was utilized for the preparation of highly dispersed pentaethylene glycol-thermally treated graphene-water as the absorbing material inside a flat-plate solar collector. Four mass fractions of nanofluids were prepared (0.025, 0.05, 0.075, and 0.1 wt% pentaethylene glycol-thermally treated graphene-water). Graphene nanoparticles were characterized by energy dispersive X-ray analysis with a scanning electron microscope. Measurements of the thermophysical properties were subsequently carried out for the nanosuspensions. The raw investigation data were collected from an indoor flat-plate solar collector test setup. The experimental procedure included different sets of variables such as input temperatures of 303, 313, and 323 K; fluid mass flow rate of 0.00833, 0.01667, and 0.025 kg s−1; and heat flow density of 500, 750, and 1000 W m−2. The thermophysical tests of pentaethylene glycol-thermally treated graphene-water nanofluids showed a proportional increase against weight concentrations, while the specific heat power was reduced. The tests showed an increment in energy efficiency by increasing the fluid mass flow rate and heat input. By comparison, the thermal efficiency decreased with the increasing temperature of the fluid supply. Relative to the base fluid, the energy efficiency of pentaethylene glycol-thermally treated graphene/water-based flat-plate solar collector increased to 10.6%, 11%, and 13.1% at the three fluid mass flow rates. In conclusion, an exponential form was used to derive the thermal effectiveness of flat-plate solar collector based on the experimental data

Energy efficiency of a flat-plate solar collector using thermally treated graphene-based nanofluids: Experimental study

© The Author(s) 2020. A covalent functionalization approach was utilized for the preparation of highly dispersed pentaethylene glycol-thermally treated graphene-water as the absorbing material inside a flat-plate solar collector. Four mass fractions of nanofluids were prepared (0.025, 0.05, 0.075, and 0.1 wt% pentaethylene glycol-thermally treated graphene-water). Graphene nanoparticles were characterized by energy dispersive X-ray analysis with a scanning electron microscope. Measurements of the thermophysical properties were subsequently carried out for the nanosuspensions. The raw investigation data were collected from an indoor flat-plate solar collector test setup. The experimental procedure included different sets of variables such as input temperatures of 303, 313, and 323 K; fluid mass flow rate of 0.00833, 0.01667, and 0.025 kg s−1; and heat flow density of 500, 750, and 1000 W m−2. The thermophysical tests of pentaethylene glycol-thermally treated graphene-water nanofluids showed a proportional increase against weight concentrations, while the specific heat power was reduced. The tests showed an increment in energy efficiency by increasing the fluid mass flow rate and heat input. By comparison, the thermal efficiency decreased with the increasing temperature of the fluid supply. Relative to the base fluid, the energy efficiency of pentaethylene glycol-thermally treated graphene/water-based flat-plate solar collector increased to 10.6%, 11%, and 13.1% at the three fluid mass flow rates. In conclusion, an exponential form was used to derive the thermal effectiveness of flat-plate solar collector based on the experimental data

Management of Post COVID 19 Mucormycosis with Osteomyelitis in The Maxilla, New Combined Consequences of The Pandemic. (Case Report).

ABSTRACT: Aim: This case report aims to demonstrate among health providers the importance of timely surgical and prosthetic management procedures of patients who suffered from the newly combined clinical entity of post COVID 19 mucormycosis and osteomyelitis of the palate. Materials and methods: Elaborate advanced diagnosis of the patients including CBCT, MRI, CT, Pathology examination, 3Ds printing reconstruction of the whole skull and digital design of reconstructive mesh that support the prosthesis were carried out. The patients undergone modified infrastructure maxillectomy and immediate prosthetic obturation of the palatal defect that was replaced later by a delayed obturator. Results: Surgical eradication of the necrotic bone and subsequent immediate obturation of the defect minimized morbidly and helped in improving the quality of life of these patients. Conclusion: Early diagnosis of this potentially fatal disease and reach-out a treatment plan immediately, is of prime importance in reducing the morbidly and mortality rate and enhance speech and eating in the two patients reported. It also decreases the psychological impact of this radical surgery

Experimental and numerical investigation of the effect of water cooling on the temperature distribution of photovoltaic modules using copper pipes

In hot climates, PV efficiency drops dramatically if the surface temperature of the panels rises over a specific limit. Consequently, a cooling system is required to preserve PV modules as close to their operating temperature as feasible. For this purpose, the influence of an increase in PV surface temperature on PV performance was studied experimentally and numerically at the Research Institute of Petroleum Industry (RIPI) in July. The current study uses a cooling system consisting of rows of copper pipes connected to the PV backside. The experiments are conducted for four distinct scenarios, each with a different input fluid temperature ranging from 19.5 to 61 °C. The parametric analysis focuses on three influential factors: ambient temperature, solar radiation, and fluid inlet temperatures. In addition, other inputs are configured in accordance with the experimental conditions. The results showed that installing a cooling water system decreased the PV surface temperature from 60.20 °C to 40.24 °C at 9:00 am and from 73.98 °C to 73.33 °C at 1:30 pm. Furthermore, the electrical, thermal, overall, and exergy efficiencies drop as radiation intensity and water inlet temperature increase. In addition, the numerical results are validated with the experimental ones, and it shows high degrees of concordance

Characterizations of Soil Collapsibility: Effect of Salts Dilution

Collapsibility of soils is the large change in volume of soil upon saturation or wetting.  This change may or may not be the result of the application of additional load.  Soil at a construction site may not always be suitable for supporting structures such as buildings, bridges, highways, and dams.  For example, if soil is placed in a certain none desire density, a large settlement will occur either due to loading or wetting of soil deposits.  Hence, a collapse will occur which will create a large subsidence or a sinkhole.In this study, soil samples of CL-ML soil were modified by adding different amounts of brine.  The main goal of which was to examine the effect of brine presence on the collapse potential of the soil.  Soil index properties, compaction characteristics, and a collapse potential were evaluated according to ASTM standards.  The test includes Atterberg's limit, Harvard miniature compaction, and double oedometer tests.It has been shown that brine additive has pronounced effect on the Atterberg’s limits; it is clearly shown that as the amount of brine increases both liquid limit and plastic limit decrease.  Compaction curve characteristics of soil were altered by the presence of brine, the maximum dry density, obtained using Harvard miniature device, increased as brine percentage increased, however, the optimum moisture content showed substantial decrease with increasing the amount of brine.

Characterizations of Soil Collapsibility: Effect of Salts Dilution

Collapsibility of soils is the large change in volume of soil upon saturation or wetting.  This change may or may not be the result of the application of additional load.  Soil at a construction site may not always be suitable for supporting structures such as buildings, bridges, highways, and dams.  For example, if soil is placed in a certain none desire density, a large settlement will occur either due to loading or wetting of soil deposits.  Hence, a collapse will occur which will create a large subsidence or a sinkhole.In this study, soil samples of CL-ML soil were modified by adding different amounts of brine.  The main goal of which was to examine the effect of brine presence on the collapse potential of the soil.  Soil index properties, compaction characteristics, and a collapse potential were evaluated according to ASTM standards.  The test includes Atterberg's limit, Harvard miniature compaction, and double oedometer tests.It has been shown that brine additive has pronounced effect on the Atterberg’s limits; it is clearly shown that as the amount of brine increases both liquid limit and plastic limit decrease.  Compaction curve characteristics of soil were altered by the presence of brine, the maximum dry density, obtained using Harvard miniature device, increased as brine percentage increased, however, the optimum moisture content showed substantial decrease with increasing the amount of brine.

Characterizations of Soil Collapsibility: Effect of Salts Dilution

Collapsibility of soils is the large change in volume of soil upon saturation or wetting.  This change may or may not be the result of the application of additional load.  Soil at a construction site may not always be suitable for supporting structures such as buildings, bridges, highways, and dams.  For example, if soil is placed in a certain none desire density, a large settlement will occur either due to loading or wetting of soil deposits.  Hence, a collapse will occur which will create a large subsidence or a sinkhole.In this study, soil samples of CL-ML soil were modified by adding different amounts of brine.  The main goal of which was to examine the effect of brine presence on the collapse potential of the soil.  Soil index properties, compaction characteristics, and a collapse potential were evaluated according to ASTM standards.  The test includes Atterberg's limit, Harvard miniature compaction, and double oedometer tests.It has been shown that brine additive has pronounced effect on the Atterberg’s limits; it is clearly shown that as the amount of brine increases both liquid limit and plastic limit decrease.  Compaction curve characteristics of soil were altered by the presence of brine, the maximum dry density, obtained using Harvard miniature device, increased as brine percentage increased, however, the optimum moisture content showed substantial decrease with increasing the amount of brine.

Graphene nanoplatelets suspended in different basefluids based solar collector: An experimental and analytical study

© 2021 by the authors. Licensee MDPI, Basel, Switzerland. A flat plate solar collector (FPSC) was analytically studied, with functionalized graphene nanoplatelets (f-GNPs) as its working fluid. Four samples (wt % nanofluids) were prepared in different base fluids such as ethylene glycol (EG), distilled water (DW):EG (70:30), and DW:EG (50:50). Experimental results (via DW) were used to verify the effectiveness of the analytical model. Some of the operating conditions were taken into account in this research, including temperatures, power, and mass flow rates. Experimental techniques were used to elucidate the modified nanofluids’ physicochemical properties, such as its particle sizes, stability, and morphology, involving electron microscopes (EMs), UV–VIS, and X-ray techniques. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) were applied to test the thermal analysis. The findings confirmed that the use of f-GNPs nanofluids enhanced the performance of the FPSC relative to the use of base fluids for all testing conditions. The maximum enhancement of the collector’s effectiveness at a mass flow rate of 1.5 kg min−1 and a weight concentration of 0.1 wt %, increased to 12.69%, 12.60%, and 12.62% in the case of EG, DW:EG (70:30), and DW:EG (50:50), respectively. The results also confirmed an improvement in both the heat gain (FR(τα)) and heat loss (FRUL) coefficients for the f-GNPs nanofluid

Impact of E-Government Applications on Reducing Administrative Burden in Delivering Public Service

The aims of this study is to look into the impact of e-government on reducing administrative burden in providing public services to citizens in the Department of Lands and Survey. The descriptive analytical research method was selected to attain the research objectives due of its utility in conducting social, business, and humanitarian studies. Employees from various employment positions made up the study sample, which included (600) male and female employees. Data was gathered from secondary sources by referring to prior studies, while primary data was gathered by using a questionnaire. The findings revealed that e-government applications have a significant role in improving the delivery of public services to citizens who visit the Department of Land and Survey, including (valid, reliable, transparent and fast public service delivery). It is recommended that the Department of Lands and Survey work continuously to update the e-government applications to keep up with changes in the business environment in providing public services, as well as provide training courses to employees to keep them informed of advancements in e-government applications. It is also recommended to give employees autonomy and the ability to participate in policymaking and decision making in order to lessen administrative hassles they face while doing their duties