Jack Legrand

Jack Legrand
University of Nantes | UNIV Nantes · Laboratoire de génie des procédés, environnement, agroalimentaire (GEPEA)

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372
Publications
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Publications

Publications (372)
Presentation
Full-text available
This study aimed to analyze some characteristics of the photosynthetic apparatus of vegetative and encysted cells obtained by continuous cultures of Haematococcus pluvialis within photobioreactors. The photosynthetic activities of whole cells confirmed that encysted cells have a higher photosynthetic capacity than assumed for non-growing cells. Thi...
Conference Paper
This work is devoted to pressure drop signals analysis to characterize the sub-regimes of intermittent flows. Experiments were carried out using air-water mixture in a horizontal 30 mm ID pipe. The sub-regimes observed are classified as Plug flow, Less Aerated Slug flow (LAS flow) and Highly Aerated Slug flow (HAS flow). Thus, a flow sub-regime map...
Article
Aim: This study aims to determine how photosynthetic and antioxidant activities vary in vegetative and dormant cells of Haematococcus pluvialis subjected to stresses in conditions representative of industrial productions of microalgae under solar light. Methods and results: The effects of short-term oxidative treatments were examined on photosyn...
Article
Single and two‐phase flows pressure drops through a Kenics static mixer were investigated, for liquid and gas Reynolds numbers ranging from 8110 < ReL < 18 940 to1730 < ReG < 8680, respectively. New friction factor correlations were established for single and two‐phase flows, showing better agreement than those available in the literature. Dissipat...
Article
Full-text available
This study aims to investigate the bio-refinery process through an enzyme-assisted extraction (EAE) on freeze-dried and fresh macroalgae Gracilaria gracilis for the release of water-soluble components (R-phycoerythrin, proteins, and sugar). Three enzymes, cellulase, protease, and enzyme cocktail (mixture of cellulase and protease), were applied in...
Article
The influence of sub-regimes of intermittent flow on the pressure drop has been investigated. Two-phase, air-water, flow experiments were conducted on 30 mm ID pipe. The superficial velocities of the working fluids were chosen to cover three sub-regimes: Plug flow, Less Aerated Slug flow (LAS flow) and Highly Aerated Slug flow (HAS flow). The analy...
Article
The purpose of this work is to analyze the influence of a sudden expansion on the upstream behavior of the horizontal gas-liquid slug flow. Measurements were made on a 40 mm ID pipe with and without a sudden enlargement of aspect ratio σ = 0.444. The experiments were carried out with two-phase air-water mixture. The slug lengths and frequencies wer...
Article
Sub-regimes of intermittent two-phase flows through a sudden expansion have been investigated experimentally. Two pipes of 30 and 40 mm ID connected by a sudden expansion with aspect ratio σ = 0.562 were used. The study was concerned by Plug, Less Aerated Slug (LAS) and Highly Aerated Slug (HAS) flows. The flow visualization showed that the liquid...
Article
Full-text available
The transition from stratified to intermittent air-water two-phase flow was investigated experimentally, by flow visualization and pressure drop signals analyses, in a 30 mm ID pipe. The intermittent flow’s onset was found to be mainly dependent on the liquid superficial velocity and the pipe diameter. Plug flow, Less Aerated Slug (LAS) or Highly A...
Article
An efficient numerical approach is proposed on the crust formation of an isothermal drying spherical colloidal droplet in a stagnant gas, where the heat and mass transfer were governed by the Stefan flow. A purely diffusive mechanism with a moving boundary was considered. The droplet shrinking induced an accumulation of particles, in the vicinity o...
Article
This study deals with the development of a self-sustained passive thermal regulation technique in Algofilm © solar photobioreactor. The reported experimental investigation includes, the evaluation of an average equivalent condensate film thickness, in indoor operating conditions, as function of the flowing liquid Tl and ambient Tamb temperatures, i...
Article
Full-text available
This study investigates the effect of condensed water droplets on the areal biomass productivity of outdoor culture systems with a free surface, protected by a transparent window or cover to prevent contamination and to control the growth conditions. Under solar radiation, evaporation from the culture causes droplets to condense on the interior sur...
Article
A microorganism culture process is a complex system in which physical operating parameters and biological responses strongly interact. Mathematical formulation and modelling of the different phenomena involved in the process...
Article
The drying process significantly affects the maintaining components offering the high added value of the dried biomass, mainly for the algae industry where the wet biomass is highly perishable. The main objective of this study is to compare the impact of drying processes that are often used in the food industry on phycobiliproteins from Arthrospira...
Article
Full-text available
In this paper we present the reactive extrusion process as a method of lipids extraction from by-products of fish. The study focuses on two essential points which are by-product enzymatic hydrolysis efficiency of three fish types, and the technical feasibility of producing a biodiesel from the fish lipids. The parameters of extrusion process were o...
Article
This study elucidates the effect of colony formation on light absorption by Botryococcus braunii microalgae cells. The spectral average mass absorption cross-section of suspensions of B. braunii cultures with free-floating cells or colonies was measured experimentally across the photosynthetically active radiation region. The average mass absorptio...
Article
Integration of solid-liquid and liquid-liquid extractions, SLE and LLE, respectively, for selective recovery of Origanum vulgare subsp. glandulosum phenolics was studied. A Two-Phase Solvent Extraction (TPSE) was performed by maceration at room temperature using a green biphasic solvent system and compared to Centrifugal Partition Extraction (CPE)....
Preprint
The purpose of this work is to analyze the influence of a sudden expansion on the upstream behavior of the horizontal gas-liquid slug flow. Measurements were made on a 40 mm ID pipe with and without a sudden enlargement of aspect ratio σ = 0.444. The experiments were carried out with two-phase air-water mixture. The slug lengths and frequencies wer...
Article
Among the intrinsic parameters identified in intermittent gas-liquid flows; slug frequency is known as the most complicated one to model. The present work concerns the investigation of slug frequency for various sub-regimes which might be found in intermittent flow. Experiments, near atmospheric pressure conditions, were carried out in a 13-meter l...
Article
Full-text available
This paper presents a quantitative visualization study and a theoretical analysis of two-phase flow relevant to polymer electrolyte membrane fuel cells (PEMFCs) in which liquid water management is critical to performance. Experiments were conducted in an air-flow microchannel with a hydrophobic surface and a side pore through which water was inject...
Book
Full-text available
Au-delà de mieux faire connaître le Génie des Procédés et ses apports de cette Science de l'Ingénieur, l'ambition de la Socitété Française de Génie des Procédés (SFGP) est de renforcer les initiatives de formation et de recherche, pour construire l’industrie de procédé du futur et relever les challenges sociétaux et environnementaux.
Book
Full-text available
PREFACE The French Society of Chemical Engineering (SFGP) provides an environment for dialogue, reflexion and innovation in the domain of industrial processes. In addition to several hundred members and the organisation of the biannual national congress in chemical engineering,the SFGP relies on a network of academic and industrial experts fromdive...
Conference Paper
Full-text available
Abstract. : In this paper we present the reactive extrusion process to extract the lipids from by-products of fish. The study focuses on the technical feasibility of using these purified lipids as an additive (between 5 and 40% dilution) in a diesel fuel for use in an engine.The parameters of extrusion process were optimised in order to extract the...
Article
Botryococcus braunii Bot-22, a hydrocarbon rich microalga known as a potential source of jet fuel, was photoautotrophically grown in a beveled shape flat-panel photobioreactor in continuous cultures. Two photon flux densities (PFD) 50 and 500 μmol photons m⁻² s⁻¹, two dilution rates, 0.178 and 0.357 d⁻¹ and two different inlet oxygen concentrations...
Article
Full-text available
Experimental investigations were conducted to study the evolution of air/water slug flow characteristics through a horizontal sudden expansion having a ratio of \(\sigma_{A}\) = 0.444. A series of acquisition of differential pressure upstream and downstream were carried out leading to statistical as well as spectral analyses. The influences of both...
Article
Full-text available
This work is devoted to a non-intrusive experimental approach, based on Laser Multi-reflection technique, in the investigation of thickness distribution variations and wave’s dynamics of a liquid film flowing over an inclined plane. This investigation was first founded on the needs of quantifying the liquid film thickness and on minimizing, as much...
Chapter
The Taylor-Couette flow is an axisymmetric, sheared, and azimuthal flow. It holds a primary site in the history of fluid dynamics. Several works have been devoted to study this problem. Despite the fact that it is very, old, the problem of Taylor-Couette flow has received renewed interests in the past years. This renaissance is due to its high inst...
Chapter
This paper presents an experimental investigation of Couette-Taylor system (CTS) characterized by a radius ratio η = 0.97 and an aspect ratio Γ = 150 to study the spatial distribution of instantaneous mass transfer and wall shear rates. Many electrochemical probes were used to measure the local and instantaneous diffusion limited current at differe...
Chapter
This work is an experimental investigation on oscillatory rotational flows with relatively high modulation frequencies and amplitudes. Two principal flow protocols have been defined and studied. The first one corresponds to advancing, stopped inner cylinder of a Couette-Taylor system with non-zero mean velocity, while the second protocol correspond...
Conference Paper
This study takes part of a larger program where the hydrothermal liquefaction (HTL) thermochemical process is used to produce an alternative bitumen from microalgal biomass. The objective is to compare the properties of non-water soluble fractions of two microalgae residues (Scenedesmus sp. and Spirulina) obtained after HTL. The process has been ca...
Article
Full-text available
This study aims to investigate the triacylglycerol (TAG) productivity of Parachlorella kessleri grown under continuous illumination and to investigate its metabolism in simulated day/night cycles in order to estimate the feasibility of a large-scale production in outdoor solar photobioreactors. The strain was chosen for its ability to accumulate la...
Article
Full-text available
The work described in this paper investigates the behaviour of paraffin material under pressure. Compressibility has been widely described in the literature but the behaviour of paraffin materials under compression is not well known. This study intends to highlight the influence of particle size and shape of paraffin material on their compressibili...
Book
An egg product is a complex matrix, mainly composed of water, proteins and lipids. It also contains carbohydrates, vitamins, minerals and many other compounds in varying concentrations. This chemical complexity makes it difficult to analyze, and most of the protocols are mainly concerned with the albumen and vitellus fractions, aside from the whole...
Article
The mechanical characteristics of a paraffin–vegetable oil material and the compressive behavior of the powder stemming from this material were used to estimate the resistance of the compressed samples. The compressive behavior of powders under the low pressure range (1–2 MPa) applied in the candle industry was investigated in order to predict the...
Article
Full-text available
This paper reports the conclusions of the three panel discussions held during the WasteEng2016 Conference in Albi, France (http://www.wasteeng2016.org/). It explores the research and development trends aiming at the production of energy and added value materials from waste and/or biomass. Three approaches are investigated: thermochemical conversion...
Conference Paper
Numerical methods for solving convection-diffusion-reaction (CDR) scalar transport equation in three-dimensional flow are used in the present investigation. The flow is confined between two concentric cylinders both the inner cylinder and the outer one are allowed to rotate. Direct numerical simulations (DNS) have been achieved to study the effects...
Article
This paper experimentally and theoretically investigates light transfer in agar-immobilized cell cultures. Certain biotechnological applications such as production of metabolites secreted by photosynthetic microorganisms require cells to be immobilized in biopolymers to minimize contamination and to facilitate metabolite recovery. In such applicati...
Article
Measuring biofuel sustainability requires dealing with a wide variety of complex and conflicting values at stake. Consequently, the biofuel capacity to contribute to one specific value cannot lead to any absolute conclusion about the overall sustainability of biofuel. The scope of the sustainability concept may vary depending on individuals’ prefer...
Article
This study aims to quantify systematically the effect of non-absorbing cap-shaped droplets condensed on the backside of transparent windows on their directional-hemispherical transmittance and reflectance. Condensed water droplets have been blamed to reduce light transfer through windows in greenhouses, solar desalination plants, and photobioreacto...
Article
This work presents the rational development up to its final characterization and validation of an intensified solar photobioreactor (PBR) for microalgal production, AlgoFilm©. Our aim was to achieve very high volumetric performance for phototrophic conditions, in the range of that found in fermentation processes.
Conference Paper
Gas-liquid two-phase flow is encountered in a wide range of engineering applications in various industrial fields. For example, in chemical and process industry two-phase flow is encountered in such facilities as boilers, condensers, evaporators and reactors. In the petroleum industry, two-phase flow is encountered during the production and transpo...
Conference Paper
Cardiovascular diseases are the major cause of death. CoA constitutes around 7% of all congenital heart diseases and is the sixth most common lesion in cardiac defect. It is usually diagnosed during childhood by routine examination of blood pressure and femoral pulse palpation but may go undetected well until adulthood with only hypertension as a m...
Conference Paper
Couette-Taylor-Poiseuille flow CTPF consists on the superposition of Couette-Taylor flow to an axial flow. The CTPF flow hydrodynamics studies remain rather qualitative or numerical or are restricted to relatively low Taylor and/or axial Reynolds numbers. For more comprehensive and control of CTPF, especially for relatively high Taylor numbers and...
Article
Here we investigate the effect of environmental pH on biomass and hydrocarbon productivity in photoautotrophic cultures of Botryococcus braunii SAG 30.81 (race A). Successive steady-states of continuous cultures were used to study the effects of pH controlled by carbon dioxide feeds in a closed photobioreactor. At a fixed dilution rate of 0.2 d− 1,...
Article
Full-text available
The Taylor-Couette problem is a fundamental model in bifurcation theory and hydrodynamic stability. The inner cylinder rotation generates a flow pattern known by a transition to turbulence through a sequence of successive hydrodynamic instabilities. The effect of an imposed axial flow on the instabilities evolution is studied. An experimental devic...