Technical note Cold storage and autonomy in a three compartments photovoltaic solar refrigerator: experimental and thermodynamic study

In this paper, we report the results of the study of the first model of solar photovoltaic refrigerator with three compartments: one for vaccine and medicines storage, the second one for the personal use of the medical staff, and the third one for water freezing. A cold storage is made around the evaporator in order to give the system several days of autonomy.The experimental study of the system has been made, as well as a dimensionment of the photovoltaic generator. The main results are the following:     

Effect of Mesona Blumes gum on physicochemical and sensory characteristics of rice extrudates

The aim of this study was to evaluate effects of Mesona Blumes gum (MBG) on some physical, chemical, sensory and antioxidant properties of rice extrudates. MBG was added to rice flour at 0%, 5%, 10%, 15% and 20% (w/w). The water solubility index (WSI) increased from 4.19% to 15.32% with MBG addition. Both water absorption index (WAI) and moisture retention (MR) reached maximum at 15% MBG. Bulk density (BD) was the highest at 5% (131.22 g cm^?3) and the lowest at 15% MBG (121.44 g cm^?3). Hardness was maximal at 5% (8.44 N mm^?2) and minimal at 15% MBG (5.98 N mm^?2). Expansion ratio (ER) and lightness (L*) decreased for all extruded products with MBG. MBG at 5% or 10% level could improve sensory characteristics of final products. The extract of extrudates at 15% MBG had the highest antioxidation ability among those extrudates. Thus, it was possible to produce a new palatable rice extrudate with MBG.     

Regional cooperation in telecommunications: two examples fromAfrica

An example of cooperation among telecommunications entities in different developing countries is examined. Two multicountry projects in sub-Saharan Africa are discussed in the framework of the International Telecommunication Union's recent recommendations for concerted actions at the regional level. The problems that the least developed countries encounter in carrying out what in the industrialized world might be considered straightforward tasks are highlighted. The examples also illustrate the difficulty of reconciling individual institutional objectives and practices and the practical limits of regional cooperation     

5 kg sternal chondroma, treated by resection and silastic prosthesis. Satisfactory result

The radioallergosorbent test (RAST) was positive in 52.5% of 200 sera representing 200 food hypersensitivities from 108 patients with a history of definite immediate-type reactions to foods. Corresponding prick test was performed for 170 of the sera. The latter test was positive in 70%, the RAST was positive in 52%, and iether prick test or RAST was positive in 74%. It is concluded that the RAST is positive less frequently than the prick test in the diagnosis of immediate-type food allergy in clinically sensitive patients, but that the performance of both tests increases slightly the possibility of confirming the diagnosis. However, the RAST is useful for further evaluating positive prick tests with foods that do not correlate with clinical hypersensitivity.     

Numerical model for the computation of permeability of a cemented granular material

We present a 3D model designed to compute permeability in a cemented polydisperse granular material composed of spherical grains. A non-cohesive granular deposit is constructed by means of the Discrete Element Method (DEM) then cement is deposited on grains using three simple models. Finally the solid sample is subjected to an upward hydraulic gradient in order to measure permeability. The fluid flow through the connected sample pores is modeled using the Lattice Boltzmann Method (LBM). The computed permeability coefficients are in good agreement with the existing classical values. The evolution of permeability with the cement deposit growth is studied for the three proposed cementation models.     

A numerical model and experimental investigation for a solar still in climatic conditions in Abidjan (Côte d''Ivoire)

A solar distillation in a single basin is studied theoretically and experimentally. We present a mathematical model to describe the energy balances for the glass cover, water in the basin and base plate. The model neglects the thermal capacity of the base plate and the temperature gradient through the width of the glass. The energy equations for the glass, water and absorber are simultaneously solved. The effects of water depth, wind speed and glass cover thickness on still productivity are evaluated. The daily total production increases with decreasing water depth. A small increasing of productivity occurs with the increase of wind speed. The thickness of the glass cover has no effect on the production. An experiment has been conducted to validate the mathematical model. The relative difference between experiment and theory is 5% for temperatures, and 15% for productivity.     

Efficient Synthesis of Immunomodulatory Drug Analogues Enables Exploration of Structure–Degradation Relationships

The immunomodulatory drugs (IMiDs) thalidomide, pomalidomide, and lenalidomide have been approved for the treatment of multiple myeloma for many years. Recently, their use as E3 ligase recruiting elements for small‐molecule‐induced protein degradation has led to a resurgence in interest in IMiD synthesis and functionalization. Traditional IMiD synthesis follows a stepwise route with multiple purification steps. Herein we describe a novel one‐pot synthesis without purification that provides rapid access to a multitude of IMiD analogues. Binding studies with the IMiD target protein cereblon (CRBN) reveals a narrow structure–activity relationship with only a few compounds showing sub‐micromolar binding affinity in the range of pomalidomide and lenalidomide. However, anti‐proliferative activity as well as Aiolos degradation could be identified for two IMiD analogues. This study provides useful insight into the structure–degradation relationships for molecules of this type as well as a rapid and robust method for IMiD synthesis.     

Thermal fatigue of cast irons for automotive application

The thermal fatigue damage constitutes the major problem of the parts subject to a variation in temperature during their operation. Several materials have been used for such structures in order to limit their damage. The facility of implementation and low cost of cast iron constitute an advantage for its use for the Diesel motors.     

Study of capillary interaction between two grains: a new experimental device with suction control

We investigated the behavior of a water liquid bridge formed between two grains. We mainly focused on tensile tests with suction control (capillary pressure). Theoretical and experimental studies are compared. A new experimental device involving suction control of the liquid bridge was developed specifically for this kind of test. Most of the liquid bridge variables and characteristics were measured by image analysis (gorge radius, volume, contact angles, filling angles). Capillary force was measured by differential weighting. Experimental conditions allows us to avoid viscous effects. Our experimental results were close to Young-Laplace equation solutions. The “gorge method”, commonly used for calculating the capillary force, was also validated by our experiments. Liquid bridge rupture was studied and a new rupture criterion is proposed. This criterion depends on the grain radius, contact angle, surface tension and suction and was in agreement with the experimental results.     

Experimental optimization of a solar still: application to alcohol distillation

This paper presents an experimental study of two solar stills, a single-compartment model and a two compartment type. The single compartment still is optimized under local climatic conditions. An experimental study of the cover slope shows that a cover angle of 16° ensures a very good transmission of solar radiation within the still while preventing the drops of the distillate to fall into the basin. In the prototype using two compartments, the glass of the illuminated compartment is a transparent cover with a part of the condensation happening on it, while the other compartment, also made of glass, is covered with a non-transparent material, which shades the sun; it is used only as a condenser. It has been observed that the distillation of a 38% alcohol initial solution yields a product containing 48% of alcohol when using the single-cover model, while under the same climatic conditions the two compartments still gives a 71% alcohol distillate.