scholarly journals Capillary Polypropylene Membranes for Membrane Distillation

Fibers ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
Marek Gryta
Keyword(s):  
Continuous Process ◽  
Negative Influence ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Porous Membranes ◽  
Surface Porosity ◽  
Permeate Flux ◽  
Thermally Induced

Only nonwetted porous membranes can be used in membrane distillation. The possibility of application in this process the capillary polypropylene membranes manufactured by thermally-induced phase separation was studied. The performance of a few types of membranes available commercially was presented. The resistance of the membranes to wetting was tested in the continuous process of water desalination. These studies were carried out for 1000 h without module cleaning. The presence of scaling layer on the membranes surface was confirmed by Scanning Electron Microscope observations. Both the permeate flux and distillate conductivity were almost not varied after the studied period of time, what indicates that the used membranes maintained their nonwettability, and the negative influence of scaling was limited. The role of surface porosity on the pore wetting and influence of membrane wettability on the quality of the distillate obtained were discussed.

scholarly journals Resistance of Polypropylene Membrane to Oil Fouling during Membrane Distillation

Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 552
Author(s):  
Marek Gryta
Keyword(s):  
Membrane Distillation ◽  
Water Desalination ◽  
Feed Water ◽  
Permeate Flux ◽  
Feed Composition ◽  
Oil Emulsion ◽  
Thermally Induced ◽  
Polypropylene Membrane ◽  
Capillary Membranes ◽  
The Impact

The influence of oil emulsion presence in the water on the course of water desalination by membrane distillation was studied. The feed water was contaminated by oil collected from the bilge water. The impact of feed composition on the wetting resistance of hydrophobic polypropylene membranes was evaluated during long-term studies. Two types of the capillary membranes fabricated by thermally induced phase separation method were tested. It has been found that these membranes were non-wetted during the separation of NaCl solutions over a period of 500 h of modules exploitation. The addition of oil (5–100 mg/L) to the feed caused a progressive decline of the permeate flux up to 30%; however, the applied hydrophobic membranes retained their non-wettability for the consecutive 2400 h of the process operation. It was indicated that several compounds containing the carbonyl group were formed on the membranes surface during the process. These hydrophilic compounds facilitated the water adsorption on the surface of polypropylene which restricted the oil deposition on the membranes used.

scholarly journals Performance Investigation of O-Ring Vacuum Membrane Distillation Module for Water Desalination

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Adnan Alhathal Alanezi ◽  
H. Abdallah ◽  
E. El-Zanati ◽  
Adnan Ahmad ◽  
Adel O. Sharif
Keyword(s):  
Flow Rate ◽  
Membrane Distillation ◽  
Membrane Module ◽  
Water Desalination ◽  
Feed Flow Rate ◽  
Permeate Flux ◽  
Vacuum Degree ◽  
Flat Sheet ◽  
Vacuum Membrane Distillation ◽  
Feed Temperature

A new O-ring flat sheet membrane module design was used to investigate the performance of Vacuum Membrane Distillation (VMD) for water desalination using two commercial polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF) flat sheet hydrophobic membranes. The design of the membrane module proved its applicability for achieving a high heat transfer coefficient of the order of 103 (W/m2 K) and a high Reynolds number (Re). VMD experiments were conducted to measure the heat and mass transfer coefficients within the membrane module. The effects of the process parameters, such as the feed temperature, feed flow rate, vacuum degree, and feed concentration, on the permeate flux have been investigated. The feed temperature, feed flow rate, and vacuum degree play an important role in enhancing the performance of the VMD process; therefore, optimizing all of these parameters is the best way to achieve a high permeate flux. The PTFE membrane showed better performance than the PVDF membrane in VMD desalination. The obtained water flux is relatively high compared to that reported in the literature, reaching 43.8 and 52.6 (kg/m2 h) for PVDF and PTFE, respectively. The salt rejection of NaCl was higher than 99% for both membranes.

scholarly journals QUALITY OF SUSTAINABILITY DISCLOSURE AMONG THE ASEAN-5 COUNTRIES AND THE ROLE OF STAKEHOLDERS

2019 ◽  
Vol 16 (2) ◽  
pp. 180-205
Author(s):  
Anisa R. Trianaputri, ◽  
◽  
Chaerul D. Djakman ◽  
Keyword(s):  
Negative Influence ◽  
Corporate Image ◽  
Contradictory Result ◽  
Social Aspect ◽  
Disclosure Quality ◽  
Stakeholder Groups ◽  
Sustainability Disclosure ◽  
Csr Disclosure

Abstract This study was carried out to reveal the actual quality of sustainability disclosure, actuated by some recent studies that pointed out the lack of disclosure quality amid the growing trend of CSR and the tendency that CSR disclosure was dominantly constructed to manage the corporate image. This study also seeks to investigate the role of stakeholder groups (primary, secondary and regulatory stakeholders), by analyzing the sustainability disclosures of 224 primary sector companies among the five emerging markets in Southeast Asia: Indonesia, Malaysia, Singapore, Thailand, and Philippines in the year of 2016. The extensive disclosure index was also employed to assess each disclosure item under the GRI G4 Guidelines. The results revealed that the quality of sustainability disclosure is still low. In this regard, Thailand turns into the country with the highest score, followed by Malaysia and Indonesia. Labor practice aspect becomes the most expressed aspect by the companies, followed by environmental and social aspect. Based on results obtained, it is therefore argued that employees, auditors, mass media, and regulators have roles in encouraging companies to enhance the quality of sustainability disclosure. However, this study does not find a significant influence from the shareholders and international consumers. The contradictory result was found from creditors, conveying that they possess a negative influence on the quality of sustainability disclosure.

scholarly journals Experimental Investigation of Heat and Mass Transfer in Tubular Membrane Distillation Module for Desalination

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Adnan Al-Hathal Al-Anezi ◽  
Adel O. Sharif ◽  
M. I. Sanduk ◽  
A. R. Khan
Keyword(s):  
Mass Transfer ◽  
Experimental Investigation ◽  
Water Vapor ◽  
Heat And Mass Transfer ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Heat Transfer Analysis ◽  
Operating Parameters ◽  
Permeate Flux ◽  
Tubular Membrane

Membrane distillation is a thermally driven membrane process for seawater desalination and purification at moderate temperatures and pressures. A hydrophobic micro-porous membrane is used in this process, which separates hot and cold water, allowing water vapor to pass through; while restricting the movement of liquid water, due to its hydrophobic nature. This paper provides an experimental investigation of heat and mass transfer in tubular membrane module for water desalination. Different operating parameters have been examined to determine the mass transport mechanism of water vapor. Based on the experimental results, the effects of operating parameters on permeate flux and the heat transfer analysis have been presented and discussed in details.

scholarly journals The The Influence of Audit Tenure and Audit Committee on Earnings Quality

2018 ◽  
Vol 19 (1) ◽  
pp. 1
Author(s):  
Fatima Zakiya Razani ◽  
Liu Xia
Keyword(s):  
Financial Reporting ◽  
Audit Committee ◽  
Stock Exchange ◽  
Listed Company ◽  
Negative Influence ◽  
Adequate Knowledge ◽  
Reporting Process ◽  
Earning Quality

One of the Auditor and Audit committee role is to ensure the quality of corporate financial reporting process. This study aims to test the effect of the length of auditor tenure and audit committee on earning quality measured by the absolute value of discretionary accruals. A sample of 465 companies has been selected and data covering the period 2009-2014 has been collected from these firms, where 2325 observation were used in this analysis. The data collected form CSMAR and analyzed using GLS regression analysis. This study found that the short audit tenure on Chinese listed company in Shenzhen Stock Exchange has a significance negative influence on earning quality, meanwhile this study found that audit committee which is measure by the size of the committee does not has a significance influence on earning quality. This study suggests that auditor should have a longer tenure to gain adequate knowledge of client’s business. Moreover companies should strengthen the role of their audit committee in monitoring financial reporting process by improved their activity and financial knowledge of the member.

scholarly journals FUNGSI PRODUKSI PUSAT KESEHATAN MASYARAKAT*

Populasi ◽  
2016 ◽  
Vol 7 (1) ◽  
Author(s):  
M. Yusril
Keyword(s):  
Community Health ◽  
Community Health Centers ◽  
Community Health Center ◽  
Work Force ◽  
Negative Influence ◽  
Positive Influence ◽  
Health Centers ◽  
Role Of Government

This study on the productivity of the Community Health Centers was carried out in the province of Bengkulu. 31 Health Centers constituted the sample used in this study, which were then divided into three categories, that is, category 1, comprising of 1 Community Health Center, category 2, comprising of 17 Health Centers, and category 3, comprising of 13 Health Centers. This study was aimed at determining the factors which influence the productivity of Community Health Centers.The results of the study indicate that the role of leadership, the implementing work force, the place of service, the duration of the service, and the budget,allhavea positive influence on the productivity of the Community Health Centers. On the other hand however, the service charges, and the health service substitution has a negative influence on the productivity of the Community Health Centers. This paper shows that the role of government is still very dominant in improving on the productivity and the quality of the Community Health Centers, particularly in funding and deploying professional workforce (leaders, paramedics and non-paramedics).

scholarly journals Evaluating Critical Influencing Factors of Desalination by Membrane Distillation Process—Using Multi-Criteria Decision-Making

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 164
Author(s):  
Ali E. Anqi ◽  
Azam A. Mohammed
Keyword(s):  
Influencing Factors ◽  
Fuzzy Ahp ◽  
Thermal Power ◽  
Feed Solution ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Membrane Thickness ◽  
Permeate Flux ◽  
Wide Range ◽  
Feed Channel

Water desalination by membrane distillation (MD) can be affected by a wide range of operating parameters. The present work uses combinational approach of Analytical Hierarch process (AHP) and Fuzzy Analytical Hierarchy process (Fuzzy-AHP) to identify the most important parameters in the MD desalination. Five process parameters and key-performance indicators, named derivable outputs (DOs), are considered, along with the critical factors affecting these DOs in the current study. The DOs and the critical influencing factors (CIFs) are selected based on their experimental feasibility. The investigation involves five DOs, which are liquid entry pressure, thermal power consumption, permeate quality, permeate flux, and pumping (feed circulation) power. A total of twenty-five critical influencing factor were associated with the DOs. The identification of the DOs and CIFs was based on the literature review, and further analyses were performed. Both methods, AHP and Fuzzy-AHP, determined six extremely important CIFs in the desalination MD, which are feed temperature, feed concentration, or feed salinity; feed flow rate; membrane hydrophobicity; pore size; and membrane material. Moderately important CIFs are found to be four by both methods. These common CIFs are feed solution properties, membrane thickness, feed channel geometry, and pressure difference along the feed channel. Finally, the least preferred CIFs are four common in both methods that are MD configuration, duration of test, specific heat of feed solution, and viscosity.

scholarly journals Does Quality of Government Matter in Public Health?: Comparing the Role of Quality and Quantity of Government at the National Level

2019 ◽  
Vol 11 (11) ◽  
pp. 3229 ◽  
Author(s):  
Sunhee Kim ◽  
Jaesun Wang
Keyword(s):  
Public Health ◽  
Life Expectancy ◽  
Positive Impact ◽  
National Level ◽  
Negative Influence ◽  
Role Of Government ◽  
Government Effectiveness ◽  
The Impact

This study aims to examine the degree of direct or indirect impact of quality and quantity of government on public health. It is a very important topic in that previous studies did not consider the role of government; they focused on the impact of national economic, social, and political factors on public health, therefore, disregarding the governmental factors. We measured the quantity of government by public expenditure on heath (i.e., rate of share of government budget to gross domestic product (GDP)) and the quality of government by five variables such as corruption control, government effectiveness, regulatory quality, voice and accountability, and rule of law. Based on national-level panel data (three waves) that covered 148–194 countries, we examined how quality and quantity of government has an impact on four kinds of public health, i.e., infant mortality, under-five mortality, maternal mortality, and life expectancy. Results show that both the quality and quantity of government had a significant impact on public health. In the quality of government, government effectiveness has a positive impact on life expectancy and a negative influence on infant deaths. Moreover, the quality of government has a greater impact on public health than the quantity of government. Lastly, the quality of government plays a role in moderating the relationships between quantity of government and the predicted variables.

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