Critical review of different aspects of liquid-solid mixing operations

2020 ◽  
Vol 36 (5) ◽  
pp. 555-592 ◽  
Author(s):  
Prakash Mishra ◽  
Farhad Ein-Mozaffari

AbstractMechanically stirred slurry tanks are utilized in several industries to perform various unit operations such as crystallization, adsorption, ion-exchange, suspensions polymerization, dispersion of solid particles, leaching and dissolution, and activated sludge processes. The major goal of this review paper is to critically and thoroughly analyse the different aspects of previous research works reported in the literature in the field of liquid-solid mixing. This paper sheds light on the advantages and limitations of various particle concentration measurement methods employed to assess the suspension quality and the extent of solid suspensions in slurry reactors. Attempts are being made to identify and compare various mathematical models and methods to quantify particle dispersion and distribution in slurry reactors. It has been shown that various factors such as geometric configurations, agitation conditions, and physical characteristics of liquid and solid have pronounced influence on local suspension quality and power consumption. Computational fluid dynamics (CFD) modeling can be extremely useful in assessing the suspension of solid particles in slurry tanks. A critical review of different scale-up procedures employed for solid suspension and distribution in liquid-solid systems is presented as well. The findings of this review paper can be useful for future research works in liquid-solid mixing.

Proteins are an integral part of molecular and cellular structure and function and are probably the most purified type of biological molecule. In order to elucidate the structure and function of any protein it is first necessary to purify it. Protein purification techniques have evolved over the past ten years with improvements in equipment control, automation, and separation materials, and the introduction of new techniques such as affinity membranes and expanded beds. These developments have reduced the workload involved in protein purification, but there is still a need to consider how unit operations linked together to form a purification strategy, which can be scaled up if necessary. The two Practical Approach books on protein purification have therefore been thoroughly updated and rewritten where necessary. The core of both books is the provision of detailed practical guidelines aimed particularly at laboratory scale purification. Information on scale-up considerations is given where appropriate. The books are not comprehensive but do cover the major laboratory techniques and common sources of protein. Protein Purification Techniques focuses on unit operations and analytical techniques. It starts with an overview of purification strategy and then covers initial extraction and clarification techniques. The rest of the book concentrates on different purification methods with the emphasis being on chromatography. The final chapter considers general scale-up considerations. Protein Purification Applications describes purification strategies from common sources: mammalian cell culture, microbial cell culture, milk, animal tissue, and plant tissue. It also includes chapters on purification of inclusion bodies, fusion proteins, and purification for crystallography. A purification strategy that can produce a highly pure single protein from a crude mixture of proteins, carbohydrates, lipids, and cell debris to is a work of art to be admired. These books (available individually or as a set)are designed to give the laboratory worker the information needed to undertake the challenge of designing such a strategy.


Electronics ◽  
2021 ◽  
Vol 10 (14) ◽  
pp. 1670
Author(s):  
Waheeb Abu-Ulbeh ◽  
Maryam Altalhi ◽  
Laith Abualigah ◽  
Abdulwahab Ali Almazroi ◽  
Putra Sumari ◽  
...  

Cyberstalking is a growing anti-social problem being transformed on a large scale and in various forms. Cyberstalking detection has become increasingly popular in recent years and has technically been investigated by many researchers. However, cyberstalking victimization, an essential part of cyberstalking, has empirically received less attention from the paper community. This paper attempts to address this gap and develop a model to understand and estimate the prevalence of cyberstalking victimization. The model of this paper is produced using routine activities and lifestyle exposure theories and includes eight hypotheses. The data of this paper is collected from the 757 respondents in Jordanian universities. This review paper utilizes a quantitative approach and uses structural equation modeling for data analysis. The results revealed a modest prevalence range is more dependent on the cyberstalking type. The results also indicated that proximity to motivated offenders, suitable targets, and digital guardians significantly influences cyberstalking victimization. The outcome from moderation hypothesis testing demonstrated that age and residence have a significant effect on cyberstalking victimization. The proposed model is an essential element for assessing cyberstalking victimization among societies, which provides a valuable understanding of the prevalence of cyberstalking victimization. This can assist the researchers and practitioners for future research in the context of cyberstalking victimization.


Author(s):  
Gert Kootstra ◽  
Xin Wang ◽  
Pieter M. Blok ◽  
Jochen Hemming ◽  
Eldert van Henten

Abstract Purpose of Review The world-wide demand for agricultural products is rapidly growing. However, despite the growing population, labor shortage becomes a limiting factor for agricultural production. Further automation of agriculture is an important solution to tackle these challenges. Recent Findings Selective harvesting of high-value crops, such as apples, tomatoes, and broccoli, is currently mainly performed by humans, rendering it one of the most labor-intensive and expensive agricultural tasks. This explains the large interest in the development of selective harvesting robots. Selective harvesting, however, is a challenging task for a robot, due to the high levels of variation and incomplete information, as well as safety. Summary This review paper provides an overview of the state of the art in selective harvesting robotics in three different production systems; greenhouse, orchard, and open field. The limitations of current systems are discussed, and future research directions are proposed.


Buildings ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 29
Author(s):  
Ning Gu ◽  
Peiman Amini Behbahani

Computational creativity in built environment (BE) design has been a subject of research interest in the discipline. This paper presents a critical review of various ways computational creativity has been and can be defined and approached in BE design. The paper examines a comprehensive body of contemporary literature on the topics of creativity, computational creativity, and their assessment to identify levels of computational creativity. The paper then proceeds to a further review of the implications of these levels specifically in BE design. The paper identifies four areas in BE design where computational creativity is relevant. In two areas—synthesis (generation) and analysis—there is considerable literature on lower levels of computational creativity. However, in two other areas—interfacing and communication—even the definition of computational creativity is not as defined and clear for the discipline, and most works only consider the role of computers as a supporting tool or medium. These open up future research opportunities for the discipline.


2021 ◽  
pp. 147059312098339
Author(s):  
Per Echeverri ◽  
Per Skålén

The aim of this conceptual article is to both provide a critical review of research into value co-destruction (VCD) and outline a common conceptual framework in order to better understand and guide future research into VCD and value co-creation (VCC). This review finds that the VCD stream of research has followed two lines of enquiry: one that highlights the role of resources and service systems and another that focuses on practices. It further finds that some prior research has argued that a direct and reciprocal relationship exists between VCD and VCC, captured in the concept of interactive value formation (IVF). A synthesizing IVF framework is outlined which suggests that the alignment and misalignment both within practices and in-between different practices determines IVF, that is, VCD and VCC. The framework further suggests that IVF is both enabled and constrained by resources and service systems.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yusheng Lu ◽  
Jiantong Zhang

PurposeThe digital revolution and the use of big data (BD) in particular has important applications in the construction industry. In construction, massive amounts of heterogeneous data need to be analyzed to improve onsite efficiency. This article presents a systematic review and identifies future research directions, presenting valuable conclusions derived from rigorous bibliometric tools. The results of this study may provide guidelines for construction engineering and global policymaking to change the current low-efficiency of construction sites.Design/methodology/approachThis study identifies research trends from 1,253 peer-reviewed papers, using general statistics, keyword co-occurrence analysis, critical review, and qualitative-bibliometric techniques in two rounds of search.FindingsThe number of studies in this area rapidly increased from 2012 to 2020. A significant number of publications originated in the UK, China, the US, and Australia, and the smallest number from one of these countries is more than twice the largest number in the remaining countries. Keyword co-occurrence is divided into three clusters: BD application scenarios, emerging technology in BD, and BD management. Currently developing approaches in BD analytics include machine learning, data mining, and heuristic-optimization algorithms such as graph convolutional, recurrent neural networks and natural language processes (NLP). Studies have focused on safety management, energy reduction, and cost prediction. Blockchain integrated with BD is a promising means of managing construction contracts.Research limitations/implicationsThe study of BD is in a stage of rapid development, and this bibliometric analysis is only a part of the necessary practical analysis.Practical implicationsNational policies, temporal and spatial distribution, BD flow are interpreted, and the results of this may provide guidelines for policymakers. Overall, this work may develop the body of knowledge, producing a reference point and identifying future development.Originality/valueTo our knowledge, this is the first bibliometric review of BD in the construction industry. This study can also benefit construction practitioners by providing them a focused perspective of BD for emerging practices in the construction industry.


2019 ◽  
Vol 54 (1) ◽  
pp. 96-111
Author(s):  
Guilherme Fowler A. Monteiro

Purpose This paper aims to conduct an extensive review and advances a framework for the literature of high-growth firms (HGFs) and scale-ups. Design/methodology/approach This paper takes the form of a literature review. Findings The author makes three specific contributions. First, he presents a broad review of high growth in firms, shedding light on the different levels of analysis. Second, he advances a characterization of scale-up companies to enable a better basis for discussion. Finally, he identifies gaps in the existing literature and suggest paths for future research. Originality/value The interest in HGFs and those referred to as scale-ups has increased considerably in recent years. Despite this trend, existing studies still have conceptual divergences and a gap separating theoretical inputs from the actual experiences of entrepreneurs.


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