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The purpose of this research paper is to investigate the changes in free volume by adding acrylate modified nanodiamond particles. In this study, a cross-linked thiol-ene (T) network was obtained under ultraviole light. The changes in free volume were analyzed when acrylate-modified nanodiamond (M-ND) particles were added to the nanocomposites obtained. Positron annihilation lifetime spectroscopy (PALS), a well-established method, was used for this analysis. In addition, the effect of nanocomposites containing different ratios of acrylate M-ND particles (1, 2, 3 and 5 Wt. %) on the surface and the thermal properties were also examined.

The impact of different quantities of acrylate M-ND on the free volume and surface morphological properties of thiol-ene polymer networks were studied by using scanning electron microscopy, differential scanning calorimetry, attenuated total reflection, Fourier transform infrared spectroscopy, PALS and thermogravimetric analysis measurements.

The thermal properties of T/M-ND were found to depend on the weight percentages of the M-ND content. For increasing weight percentages of M-ND added to thio-lene polymer networks, the glass transition temperature (T_g) increased from 103°C to 154°C. The ortho-positronium (o-Ps) lifetime (free volume) and free volume fraction characterization of T/M-ND nanocomposites were investigated using PALS. Increasing temperature caused both the o-Ps lifetime (free volume) to change with increasing saturation and to linearly increase the intensity; however, an increasing weight percentage of M-ND caused no change at all for the o-Ps lifetime (free volume) and the free volume fraction.

According to published literature, and to the best of the authors’ knowledge, this is the first time a study examining the free volume properties in a thiol-ene system has been carried out.

The volume of fluid (VOF) method is a numerical technique to track the developing free surfaces of liquids in motion. This method can, for example, be applied to compute the liquid flow patterns in a rotating cone reactor. For this application a spherical coordinate system is most suited. The novel derivation of the extended VOF algorithms for this class of applications is presented here. Some practical limitations of this method, that are inherent in the geometry of the described system, are discussed.

Maintainability, as an intrinsic property that shows how well a product can be maintained, should be strictly controlled in the design stage. Maintenance space is an important aspect of maintainability and should be verified in the design stage. Methods to verify maintenance space based on expert knowledge or vision cone have been proposed. However, no proper quantitative solutions have been proposed yet to verify maintenance space in the design stage. This paper aims to provide a new method to evaluate quantitatively the maintenance space in a virtual environment by using the swept volume (SV).

An integrated platform for quantitatively evaluating maintenance space in a virtual environment is designed. Virtual reality technology and digital prototype are used to overcome the shortage of physical prototypes in the design stage. SVs are applied to represent the movement of the hand along the entire maintenance process. Maintenance operations are divided into three basic types. Each type of basic operation refers to two quantitative indexes, namely the surface area and the volume of the SV of the maintenance personnel. Data on the indexes are gathered and calculated to evaluate maintenance space.

The proposed methodology can evaluate feasibly and efficiently the maintenance space determined by the layout design of product components in the design stage.

Application of the proposed method can help designers reduce the shortness of maintenance space and improve the design layout of products.

A method to evaluate maintenance space that employs a quantitative combination of virtual environment and swept volume is pressed.

This paper aims to analyse remotely piloted aircraft system (RPAS) integration in non-segregated terminal airspace. This work aims to identify the potential airspace volumes where a free operation of RPAS can be developed by analysing the airspace design of the terminal airspace.

The methodology considers five crucial elements of the airspace design: obstacles, prohibited, restricted and dangerous zones, aerodrome zones, departing and arriving procedures and visual corridors. Free operation of RPAS is performed in those airspace volumes that no interaction with instrumental flight rules (IFR) flights is expected. Free RPAS airspace volumes are separated through current IFR separation minima.

The results show there is a significant amount of available airspace that RPAS can operate without interaction with conventional aircraft. The more significant risks are allocated by the limitations imposed by departing and arriving procedures in the terminal airspace.

The methodology is applied to medium-dense terminal airspace. This work assumes RPAS can perform visual or instrumental flights.

RPAS is a capital issue for the majority of aviation actors. This work underlay the further development of a methodology regarding airspace design for RPAS in a terminal control area.

This article describes new approaches in rapid prototyping large sand moulds using industrial robots. In contrast to state of the art processes, the new approaches work three‐dimensionally taking advantage of the large working area of industrial robots.

The distribution of the deformations of elementary cells is studied in an abstract lattice constructed from the existence of the empty set. One combination rule determining oriented sequences with continuity of set‐distance function in such spaces provides a particular kind of space‐time‐like structure which favors the aggregation of such deformations into fractal forms standing for massive objects. A correlative dilatation of space appears outside the aggregates. At large scale, this dilatation results in an apparent expansion, while at submicroscopic scale the families of fractal deformations give rise to families of particle‐like structure. The theory predicts the existence of classes of spin, charges and magnetic properties, while quantum properties associated with mass have previously been shown to determine the inert mass and the gravitational effects. When applied to our observable space‐time, the model would provide the justifications for the existence of the creation of mass in a specified kind of void, and the fractal properties of the embedding lattice extend the phenomenon to formal justifications of big‐bang‐like events without any need for supply of an extemporaneous energy.

The objective of this article is to propose a panel of management performance evaluation indicators at operator level. This panel would be the tool to be made available to an observatory that should be set up by regulation. The proposal comes at the right time given that Morocco is planning a major reform of the sector very soon. A framework law has already been promulgated for this purpose (Law 51-21 relating to the reform of public establishments).

The proposed panel is the result of (1) a review of the literature dealing with public management theories, in particular those relating to industrial and commercial public services and whose character is captive. The management of the latter requires a great deal of caution to preserve their economic balance and consequently their sustainability. (2) A review of experiences of countries is chosen because of contextual their similarities with Morocco like France having a similar legal background, Tunisia and Algeria chosen for geographical and economic similarities. The British experience is also discussed for what it represents as a liberal model in the management of public water and sanitation services, as opposed to the German model also studied and which stands as the only country where the management of public services has almost always been a communal prerogative. The analysis of these models has made it possible to identify management evaluation practices that could be adapted to the Moroccan context. (3) Research work by practitioners and reports from specialized international institutions (International Water Association [IWA]). (4) A critical analysis of a multitude of management and activity reports from 12 autonomous authorities and 4 private delegates covering 16 million inhabitants of the urban environment. A total of 15 indicators are developed. They aim to assess the effectiveness of management in terms of saving drinking water and preserving the natural environment from the pollution of water resources.

Approximately, 15 indicators for assessing water resource management in public water and sanitation services are proposed. These indicators relate to the efficiency of pipe networks, the performance of storage systems and losses in users' homes. Indicators specific to liquid sanitation systems, particularly with regard to the control of wastewater overflows into the public highway and their treatment before discharge into the natural environment, are also proposed.

The application of the results of this research could be confronted with its appropriation by the operators. Indeed, the investment involved in setting up the proposed evaluation system, as well as the conflict of interest that may arise in the process of formalizing and standardizing the system at the national level, may slow down the process of setting it up.

In practice, the implementation of a system for evaluating the performance of water resource management in public drinking water and liquid sanitation services would make it possible to optimize the volume of water to be mobilized. Substantial savings are expected both at the level of the resource itself and at the level of the investments that accompany the realization of the mobilization and distribution infrastructures. These savings will be very useful for the creation of other similar services and to serve more people.

The distribution of drinking water and liquid sanitation is a vital human need. These services are extremely captive. They are key factors in the socioeconomic development of the territory and the citizen. The impact is transversal and affects the lifestyle of the populations. On the one hand, it favors the sedentarization of the populations and on the other hand, preserves their health by fighting against the diseases of water origin. In addition, the comfort that it provides in the daily life of users is highly coveted when they are delivered in a modern way and arranged with modern technologies.

The regulation of public drinking water and liquid sanitation services in Morocco is the weakest link in the sector. The Ministry of the Interior is legally responsible for setting up a standard system for evaluating the management of these services to fill this gap (organic law 113-14 on municipalities). Unfortunately, this initiative is not yet underway. The opportunity to apply the results of this research is well timed. Morocco plans to launch a global reform of the sector starting in 2022–2023 (Law 50-21 on the reform of public institutions).

The aim of this paper is to describe the preparation and characterisation of poly(methyl methacrylate) (PMMA) (Mw: 996,000) and dammar mixtures to obtain a new series of natural coating materials for application on mild steel substrates. Dammar is a natural resin extracted from Dipterocarpus Grandiflorus sp., or kruing trees, which grow mainly in the tropical Asia Pacific forest.

Natural dammar resin was mixed with PMMA at different weight percentages in xylene as a solvent and dammar as dominant component. The mixtures were applied on mild steel Q‐panels to form dry coating films. The coating films were investigated under Attenuated Total Reflection‐Fourier Transforms Infrared (ATR‐FTIR) technique to observe the presence of functional groups from PMMA and dammar. Resistivity of coating films against corrosive agents from electrolytes was measured by using potential time measurement (PTM) technique. ASTM D3359 (cross‐hatch) technique was used to measure the coating film adhesion strength on the substrate. The entire tests were conducted at 28°C.

Natural dammar resins is potentially applicable for coating on cold rolled mild steel Q‐panel when mixed with PMMA. Blended dammar resin with PMMA in 5:5 ratio (coded as DP50) was found to give the highest energy of rapid impact indenter. Cross‐hatch test under ASTM D3359 revealed that 50 percent w/w of dammar in PMMA had increased the adhesion strength of the coating film where there was no coating area peeling off from the substrate after the test. DP50 also had the longest time to resist penetration of electrolytes through the coating film when immersed in salt water.

Decreasing the amount of dammar lower than 50 percent weight ratio with PMMA will cause high viscosity and inhomogeneous mixtures.

Natural dammar resin mixed with PMMA (behaviour naturally in free standing film) for coating paint application was formulated.

The purpose of this paper is to expand the theoretical meaning and application of the separate components of the interaction coefficient as obtained from the generalized viscosity model.

Both theoretical and experimental analysis have been utilized to better understand the meaning of the separate components of the interaction coefficient obtained from the generalized viscosity model. Analysis of the experimental data of Schaller and Humphrey has been used to successfully isolate the separate components of the interaction coefficient.

The relative unhindered volume is the volume outside the sphere of influence of a particle that is responsible for the viscosity characteristics of a coating. This is the volume available for particles to move in the suspension and still contribute to the viscosity. The smaller the relative unhindered volume the higher the viscosity. As the interaction coefficient, σ, increases the particles increase their interaction with each other and the relative unhindered volume decreases. Using the data of Schaller and Humphrey, it was found that the interaction coefficient agreed best with the theoretical expectation relative to particle size when the ionic strength was low. At high levels of ionic strength, the solvent‐particle component of the interaction coefficient was dominant and the influence of particle size on the interaction coefficient was minimal.

Only one set of experimental data was successfully utilized for illustrative purposes in this study but the resulting analysis has implicated a broad range of practical applications. In addition, the general theoretical concepts elucidated relative to the interaction coefficient should still be applicable independent of the experimental results.

The analysis presented in this paper provides several practical guidelines to separate and control the charge component of pigments in a suspension from their size component using the interaction coefficient as described in this study. Consequently, the results of this study should provide several new practical approaches to use when attempting to control the viscosity of suspensions for a broad range of practical applications and for a broad range of suspension types including coatings.

This is the first time that the theoretical statistical character of the interaction coefficient as indicated in the generalized viscosity model has been specifically elucidated. In addition, the relatively simple experimental separation of the interaction coefficient into its size and electrical components has been shown to be widely applicable in this paper.

The purpose of this paper was to show that the generalised viscosity model can correctly characterise suspension data over both a wide range of concentration as well as a wide range of temperature. A second objective of this study was to show theoretically and experimentally how the interaction coefficient from the generalised viscosity model also appears to have some thermodynamic properties.

In this study, many well‐known suspension equations were shown mathematically to be subsets of the generalised viscosity equation. The generalised viscosity equation was also found to be able to be reduced mathematically to two well‐known dilute solution equations (Huggins and Kramer's equations) as well. The relationship between Huggins and Kramer's constants and the interaction coefficient from the generalised viscosity equation yielded the potential to evaluate the solubility characteristics of the interaction coefficient. The value of the interaction coefficient was then found to be able to be evaluated as a function of temperature to enhance an understanding of the thermodynamic characteristics of the interaction coefficient using the data of Bueche.

In this study, a polymer plasticiser system involving polymethyl methacrylate in the plasticiser diethyl phthalate yielded an interaction coefficient, σ, primarily in the expected plasticiser range from 0< σ<1. It was also found that the generalised viscosity equation fit Bueche's polymer plasticiser data remarkably well over the whole concentration range for temperatures ranging from 30°C to 140°C. This study also appeared to show that the interaction coefficient from the generalised viscosity model can apparently characterise thermal transitions as well as thermodynamic solubility for a polymer solute (i.e. polymethyl methacrylate) when viscosity is evaluated over a wide temperature range. This result was particularly significant since Bueche's data covered 25 decades of viscosity on a log scale.

This is the first paper to successfully explore the thermodynamic characteristics of the interaction coefficient of the generalised viscosity equation. This opens up new avenues for evaluating the solubility and thermodynamic characteristics of various additives in solutions and polymeric formulations.