Pressure-Retarded Osmosis Thermosyphon

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Francisco J. Arias ◽  
Salvador de las Heras
Keyword(s):  
Natural Convection ◽  
Salinity Gradient ◽  
Fluid Motion ◽  
High Concentration ◽  
Thermal Dependence ◽  
Heat And Mass Transport ◽  
Pressure Retarded Osmosis ◽  
Dense Fluid ◽  
Novel Method ◽  
The Cost

The basis of a novel method for passive solar water heating homologous to the traditional thermosyphon but driven by salinity gradient induced by changes of salinity gradient induced by evaporation at the collector is outlined. Its purpose, likewise than a thermosyphon, is to simplify the transfer of liquid while avoiding the cost and complexity of a conventional pump. However, in this concept, the fluid motion is not obtained from the tendency of a less dense fluid to rise above a denser fluid (natural convection) but rather by taking advantage of the energy released during the spontaneous mixing of the low-concentration (evaporated fraction) solution and the high-concentration (no-evaporated fraction) solution, which have been previously separated into two streams in the evaporator module. Finally, the possibility of driving the thermal osmosis by the strong thermal dependence of the solubility featured by many solutions rather than evaporation is envisaged. One important point in favor of the proposed thermosyphon driven by thermo-osmosis is that makes possible downward heat and mass transfer, i.e., heat and mass transport from the top roofs (where solar collectors are generally placed) to the bottom (inside the homes), and then the use of expensive and voluminous tanks so characteristic of current thermosyphons driven by natural convection is no longer needed.

scholarly journals Cost Analysis of a Novel Method for Ecological Compensation—A Study of the Translocation of Dead Wood

2021 ◽  
Vol 13 (11) ◽  
pp. 6075
Author(s):  
Ola Lindroos ◽  
Malin Söderlind ◽  
Joel Jensen ◽  
Joakim Hjältén
Keyword(s):  
Cost Efficiency ◽  
Dead Wood ◽  
Road Transportation ◽  
Ecological Value ◽  
Ecological Compensation ◽  
Work Time ◽  
Delivery Times ◽  
Novel Method ◽  
Cost Efficient ◽  
The Cost

Translocation of dead wood is a novel method for ecological compensation and restoration that could, potentially, provide a new important tool for biodiversity conservation. With this method, substrates that normally have long delivery times are instantly created in a compensation area, and ideally many of the associated dead wood dwelling organisms are translocated together with the substrates. However, to a large extent, there is a lack of knowledge about the cost efficiency of different methods of ecological compensation. Therefore, the costs for different parts of a translocation process and its dependency on some influencing factors were studied. The observed cost was 465 SEK per translocated log for the actual compensation measure, with an additional 349 SEK/log for work to enable evaluation of the translocation’s ecological results. Based on time studies, models were developed to predict required work time and costs for different transportation distances and load sizes. Those models indicated that short extraction and insertion distances for logs should be prioritized over road transportation distances to minimize costs. They also highlighted a trade-off between costs and time until a given ecological value is reached in the compensation area. The methodology used can contribute to more cost-efficient operations and, by doing so, increase the use of ecological compensation and the benefits from a given input.

Electrokinetic Power Generation by Forward Osmosis

2012 ◽  
Author(s):  
Kar Cherng Hon ◽  
Chun Yang ◽  
Seow Chay Low
Keyword(s):  
Power Generation ◽  
Salinity Gradient ◽  
Forward Osmosis ◽  
Streaming Potential ◽  
Nacl Solution ◽  
Direct Power ◽  
Concentration Difference ◽  
Permeable Membrane ◽  
Flat Sheet ◽  
Novel Method

In this paper, an innovative direct power generation technique from salinity gradient is proposed and demonstrated. The basis of this novel method encompasses forward osmosis (FO) and electrokinetic (EK) principles. Tapping the concentration difference between seawater and river fresh water, forward osmosis (FO) is utilized to allow for spontaneously transporting water across a semi-permeable membrane. The flow of water is then directed towards array of microchannels in the form of porous medium where power is produced from the electrokinetical streaming potential. Experimentally, NaCl solution and DI water were used to model as seawater and fresh river water, respectively. Both glass and polymer based porous media and commercial flat sheet FO membranes were employed herein. Results show power density could reach the order of 101W/m2. Having features of ease of fabrication, simple configuration and no mechanical moving parts, this method provides a feasible mean to harvest enormous energy from salinity gradient. Thus the proposed technique could contribute greatly to renewable energy and towards sustainable future.

scholarly journals Embedding Undersampling Rotation Forest for Imbalanced Problem

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Huaping Guo ◽  
Xiaoyu Diao ◽  
Hongbing Liu
Keyword(s):  
Imbalanced Data ◽  
Feature Space ◽  
Original Data ◽  
Training Set ◽  
Data Set ◽  
Minority Class ◽  
Rotation Forest ◽  
Novel Method ◽  
Individual Classifier ◽  
The Cost

Rotation Forest is an ensemble learning approach achieving better performance comparing to Bagging and Boosting through building accurate and diverse classifiers using rotated feature space. However, like other conventional classifiers, Rotation Forest does not work well on the imbalanced data which are characterized as having much less examples of one class (minority class) than the other (majority class), and the cost of misclassifying minority class examples is often much more expensive than the contrary cases. This paper proposes a novel method called Embedding Undersampling Rotation Forest (EURF) to handle this problem (1) sampling subsets from the majority class and learning a projection matrix from each subset and (2) obtaining training sets by projecting re-undersampling subsets of the original data set to new spaces defined by the matrices and constructing an individual classifier from each training set. For the first method, undersampling is to force the rotation matrix to better capture the features of the minority class without harming the diversity between individual classifiers. With respect to the second method, the undersampling technique aims to improve the performance of individual classifiers on the minority class. The experimental results show that EURF achieves significantly better performance comparing to other state-of-the-art methods.

scholarly journals PROFITABILITY ANALYSIS OF MARKETING OF FROZEN FISH IN KADUNA METROPOLIS, KADUNA STATE, NIGERIA

2020 ◽  
Vol 4 (2) ◽  
pp. 577-583
Author(s):  
M. B. Usman ◽  
O. S. Aaasa ◽  
O. S. Balogun ◽  
U. F. Yahaya
Keyword(s):  
Tertiary Education ◽  
Primary Data ◽  
Integrated Marketing ◽  
High Concentration ◽  
Profitability Analysis ◽  
Multi Stage ◽  
Return On Capital ◽  
Result Show ◽  
Frozen Fish ◽  
The Cost

This study investigated the marketing of frozen fish in Kaduna metropolis, Kaduna state. Ten (10) markets were purposively selected due to high concentration of frozen fish marketers and the volume of trading activities; Primary data were generated through the use of structured questionnaire administered to hundred (100) randomly selected retailers and fifteen (15) purposively selected wholesalers. The data were analyzed using descriptive statistic, budgeting technique, net marketing and rate of return on capital invested. The result show that majority 80 percent and 53 of the retailers and wholesalers were female, Majority (70prcent) of the retailers had primary education but most of the wholesaler’s attained tertiary education. The frozen fish marketing channels identified in the area are made up of zero and multi stage channels. Furthermore, the cost and return analysis revealed that the wholesalers realized about N121, 000.00 naira while the retailers got N56, 000.00 naira per month while return to per capital invested (RPCI) was 11 kobo and 22 kobo per Naira invested for the wholesalers and the retailers respectively. This implies that the enterprise is profitable. Transportation difficulties and marketing charges ranked were major constraints confronting frozen fish marketers. It is recommended that provision of good roads network and formidable integrated marketing system will further improve the profitability of the enterprise in the study area.

Design of Fazl-Tash novel method for sustainable resilient comprehensive supplier selection problem

Kybernetes ◽  
2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hamed Fazlollahtabar ◽  
Navid Kazemitash
Keyword(s):  
Supplier Selection ◽  
Huge Number ◽  
Simple Method ◽  
Content Type ◽  
Novel Method ◽  
Rank And Select ◽  
The Cost ◽  
Supplier Selection Problem ◽  
Industrial Company

Purpose However, due to the huge number of studies and on the other hand to be new and creative, the represented models and methods – as the two main parts of this field – have been got more complicated, which consequently have been turned into unpractical research studies for the realistic situations. Therefore, the purpose of this study is the representation of a novel and simple method to deal with the aforementioned gap. Design/methodology/approach To this end, Fazl-Tash method have been proposed, in which a thorough and complete model including 114 criteria and a simple technique to rank and select the best supplier have been presented. Sustainability and resiliency are considered in collecting criteria effective on supplier selection. Findings The method was carried out in a case study in an industrial company. The efficiency of the proposed method is evaluated in comparison with other conventional approaches. Originality/value As selecting the supplier plays a crucial role to bring some important advantages for companies, such as coping with the cost and time problems and influencing the majority of contemporary markets’ requirements, in recent years, there have been representing more effective studies in the supplier selection literature.

A hybrid framework to model factors affecting construction labour productivity

2019 ◽  
Vol 24 (3) ◽  
pp. 630-654 ◽  
Author(s):  
Majid Parchami Jalal ◽  
Shahab Shoar
Keyword(s):  
Construction Industry ◽  
Labour Productivity ◽  
Content Type ◽  
Factors Affecting ◽  
Schedule Delay ◽  
Factors Influencing ◽  
Hybrid Framework ◽  
Novel Method ◽  
The Cost ◽  
The Impact

Purpose This paper aims to model different causal relations among factors interacting with labour productivity in order to recognize the most important factors influencing and influenced by it. Design/methodology/approach Top 60 factors affecting labour productivity were determined and grouped into 5 major groups by reviewing previous research and interviewing relevant experts. The interactions of factors were modelled using system dynamics (SD) approach. The resulting causal loop diagrams obtained from SD were then applied for identifying the most crucial factors influencing and influenced by labour productivity through the decision-making trial and evaluation laboratory (DEMATEL) method. The impact of factors on each other was finally determined based on the opinions of 63 experts selected from the Iranian construction industry. Findings The results indicated that factors such as fatigue, lack of labour motivation and lack of skill are the most influencing, and factors such as schedule delay and inflation in the cost of execution are the most influenced by labour productivity. In the end, a set of recommendations to improve construction labour productivity was also presented. Originality/value The main contribution of the study is proposing a novel method which is capable of providing insights into how causes and effects of construction labour productivity are interrelated. Furthermore, the proposed method makes this study distinct from previous research in the light of prioritizing factors and offering recommendations according to the interrelationships among factors.

Effect of 3D Diffusion Over Vertical Thin Rectangular Geometries in Natural Convection Heat Transfer

2006 ◽  
Author(s):  
Mustafa Gursoy ◽  
Mehmet Arik ◽  
Tunc Icoz ◽  
Michael Yovanovich ◽  
Theodorian Borca-Tasciuc
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Fluid Motion ◽  
Heat Removal ◽  
Air Entrainment ◽  
Published Data ◽  
Diffusion Term ◽  
Nusselt Numbers ◽  
Wide Range ◽  
Rayleigh Numbers

Natural convection over vertical plates is a very well known problem in heat transfer. There are many available correlations to predict Nusselt numbers for a wide range of Rayleigh numbers. These benchmark studies on natural convection for vertical plates were conducted on rather large surfaces leading to Rayleigh numbers in the range of 0.1 to 109. In natural convection the sole driving force of fluid motion is the change in fluid density, when the diffusive limit is small compared to convective heat transfer. However, conduction to air, as well as air entrainment from sides also contributes to the heat removal from heater surfaces. An experimental study has been carried out with small and large heaters compared to published data for 2×103<Ra<4×107. Square surfaces of 12.5 and 25.4 mm, and rectangular heaters of sizes 25.4×101.6 and 25.4×203.2 mm were tested for a range of heat inputs such that the surface temperatures are controlled between 30 °C and 80 °C. It is found that published correlations underpredict the Nusselt numbers as much as 20%. It is observed that widely known correlations underpredict the experimental values since the 3D conduction and side air drifts on heat transfer are not accounted for in these correlations. However, the cuboid model which includes the 3D diffusion term showed much better agreement with the experimental results.

Approaches to improve the robustness on interdependent networks against cascading failures with load-based model

2015 ◽  
Vol 29 (32) ◽  
pp. 1550210 ◽  
Author(s):  
Zhengcheng Dong ◽  
Yanjun Fang ◽  
Meng Tian ◽  
Rong Zhang
Keyword(s):  
Coupling Strength ◽  
Initial Period ◽  
Network Construction ◽  
Interdependent Networks ◽  
Coupled Networks ◽  
Novel Method ◽  
One To One ◽  
The Cost ◽  
Full Investigation ◽  
Link Pattern

With load-based model, considering the loss of capacity on nodes, we investigate how the coupling strength (many-to-many coupled pattern) and link patterns (one-to-one coupled pattern) can affect the robustness of interdependent networks. In one-to-one coupled pattern, we take into account the properties of degree and betweenness, and adopt four kinds of inter-similarity link patterns and random link pattern. In many-to-many coupled pattern, we propose a novel method to build new networks via adding inter-links (coupled links) on the existing one-to-one coupled networks. For a full investigation on the effects, we conduct two types of attack strategies, i.e. RO-attack (randomly remove only one node) and RF-attack (randomly remove a fraction of nodes). We numerically find that inter-similarity link patterns and bigger coupling strength can effectively improve the robustness under RO-attacks and RF-attacks in some cases. Therefore, the inter-similarity link patterns can be applied during the initial period of network construction. Once the networks are completed, the robustness level can be improved via adding inter-links appropriately without changing the existing inter-links and topologies of networks. We also find that BA–BA topology is a better choice and that it is not useful to infinitely increase the capacity which is defined as the cost of networks.

Numerical Solutions of Natural Convection Flow of a Dusty Nanofluid About a Vertical Wavy Truncated Cone

2016 ◽  
Vol 139 (2) ◽  
Author(s):  
Sadia Siddiqa ◽  
Naheed Begum ◽  
M. A. Hossain ◽  
Rama Subba Reddy Gorla
Keyword(s):  
Natural Convection ◽  
Mass Transport ◽  
Numerical Solutions ◽  
Convection Flow ◽  
Governing Equations ◽  
Natural Convection Flow ◽  
Two Phase ◽  
Heat And Mass Transport ◽  
Implicit Finite Difference ◽  
Control Skin

This paper reports the numerical results for the natural convection flow of a two-phase dusty nanofluid along a vertical wavy frustum of a cone. The general governing equations are transformed into parabolic partial differential equations, which are then solved numerically with the help of implicit finite difference method. Comprehensive flow formations of carrier and dusty phases are given with the aim to predict the behavior of heat and mass transport across the heated wavy frustum of a cone. The effectiveness of utilizing the nanofluids to control skin friction and heat and mass transport is analyzed. The results clearly show that the shape of the waviness changes when nanofluid is considered. It is shown that the modified diffusivity ratio parameter, NA, extensively promotes rate of mass transfer near the vicinity of the cone, whereas heat transfer rate reduces.

scholarly journals Naso-pharyngeal carriage of Haemophilus influenzae type B

1963 ◽  
Vol 61 (2) ◽  
pp. 247-256 ◽  
Author(s):  
D.C. Turk
Keyword(s):  
Haemophilus Influenzae Type ◽  
High Concentration ◽  
Senior Lecturer ◽  
Parents And Children ◽  
High Concentrations ◽  
Cost Of Materials ◽  
The Cost ◽  
Day Nursery ◽  
The University ◽  
Normal Health

H.influenzae type b, the sero-type which causes meningitis, was isolated from 3 (2·4 %) of 127 naso-pharyngeal swabs from white non-Jamaican children resident in Jamaica, and from 14 (2·9 %) of 473 such swabs from a mixed group of Jamaican children. Much higher frequencies were found in households in which cases of haemophilus meningitis had recently occurred (41 %), in the nursery of an orphan home (up to 70%) and in a day-nursery. In the orphan home nursery the high frequency persisted over a number of months, but no case of meningitis or other relevant disease occurred. A high concentration of this organism is therefore compatible with normal health, and the significance of high concentrations in the homes of meningitis patients is not certain.I am indebted to the Standing Advisory Committee for Medical Research in the British Caribbean for a grant towards the cost of materials; to a number of colleagues at the University College of the West Indies, notably Dr E. H. Back, Senior Lecturer in Paediatrics, and the staff of the Department of Social and Preventive Medicine; to those in charge of the orphan home, the day-nursery, the play-school and the other institutions visited; to many cooperative parents and children and to my wife for help in the collection of specimens.

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