Large-scale Batch Research Articles

Self-Compacting Concrete Reinforced with Twisted-Bundle Macro-Synthetic Fiber

The use of self-compacting concrete (SCC) reinforced with fibers has great potential in the precast concrete industry as the concrete can be delivered straight into the moulds, without any vibration or compacting effort. Similarly, it has the potential to replace traditional steel reinforcement depending on the design requirements. Novel synthetic fibers have recently become available in the market, but still, limited information is available on the performance of SCC reinforced with such fibers. This paper investigates the use of twisted-bundle macro-synthetic fiber in self-compacting concrete. Three different concrete mixtures with fiber dosage of 4, 6, and 8 kg/m3 were produced in large scale batches, and their performance was compared in terms of slump-flow, compressive strength, split tensile strength, modulus of elasticity, and flexural strength. Moreover, a comprehensive evaluation of the post-cracking residual strength is presented. It was found that the mixture with 4 kg/m3 fiber content has the most satisfactory flowability, whereas 8 kg/m3 mixture achieved the highest residual flexural strength. Based on the observed post-cracking behavior, a simplified stress-crack opening constitutive law is proposed. Since the fiber dosage affects the residual flexural strength, a factor related to fiber content is recommended while determining the ultimate residual flexural strength.

Company Profile: Aldevron Expands to Facilitate Emerging Therapies.

Company Profile: Aldevron Expands to Facilitate Emerging Therapies.

A Large-Scale Concurrent Data Anonymous Batch Verification Scheme for Mobile Healthcare Crowd Sensing

Recently, with the rapid development of big data, Internet of Things (IoT) brings more and more intelligent and convenient services to people's daily lives. Mobile healthcare crowd sensing (MHCS), as a typical application of IoT, is becoming an effective approach to provide various medical and healthcare services to individual or organizations. However, MHCS still have to face to different security challenges in practice. For example, how to quickly and effectively authenticate masses of bio-information uploaded by IoT terminals without revealing the owners' sensitive information. Therefore, we propose a large-scale concurrent data anonymous batch verification scheme for MHCS based on an improved certificateless aggregate signature. The proposed scheme can authenticate all sensing bio-information at once in a privacy preserving way. The individual data generated by different users can be verified in batch, while the actual identity of participants is hidden. Moreover, assuming the intractability of CDHP, our scheme is proved to be secure. Finally, the performance evaluation shows that the proposed scheme is suitable for MHCS, due to its high efficiency.

Production of hydrogen by steam oxidation of calcium ferrite reduced with various coals

Production of H2 by steam oxidation was demonstrated with calcium ferrite (CaFe2O4) after coal gasification to produce CO with several types of coals. All coal types reacted with CaFe2O4 to produce CO. The reduced CaFe2O4 after the reaction with coal can also be oxidized with steam at 800 °C while producing of H2. Sub-bituminous coal and lignite coal had better reactivity with CaFe2O4 than the bituminous coal. A ten-cycle test conducted with Wyodak coal/CaFe2O4 at 800 °C showed stable production of H2 during oxidation with steam. A 25-cycle steam oxidation test conducted after reduction of CaFe2O4 with lignite coal also showed a very stable performance. Steam oxidation is sufficient for maintaining the cyclic reactions. A larger scale (2 kg batch) production of CaFe2O4 by wet granulation-tumbling method was successful. Steam oxidation was demonstrated with the large-scale batch of CaFe2O4 after reduction with Wyodak coal.

Cryptanalysis and Improvement of an Anonymous Batch Verification Scheme for Mobile Healthcare Crowd Sensing

As an emerging application of smart healthcare, mobile healthcare crowd sensing (MHCS) has become a research hotspot. However, how to ensure the confidentiality and integrity of data and protect the privacy of user is still a challenge for MHCS. To handle these issues, an effective and secure privacy protection scheme is indispensable. Recently, a large-scale concurrent data anonymous batch verification scheme for mobile healthcare crowd sensing was proposed by Liu et al. Unfortunately, we demonstrate that their scheme is insecure. This paper presents an improved anonymous scheme based on certificateless aggregate signature (CL-AS) for MHCS. First, considering the efficiency and the characteristics of the MHCS, the technique of aggregate signature is adopted, which can achieve batch verification and greatly save the bandwidth and computation resources. Second, anonymous communication is carried out in this scheme to realize privacy preservation. Third, based on certificateless cryptography, the proposed scheme can simplify the complicated certificate management and eliminate the key escrow problem. In addition, our scheme is provably secure against the existential forgery on adaptively chosen message attack in the Random Oracle Model assuming the computational Diffie-Hellman problem is intractable. Furthermore, security and efficiency analysis shows that our scheme is secure and efficient.

A Task-Resource Mapping Algorithm for Large-Scale Batch-Mode Computational Marine Hydrodynamics Codes on Containerized Private Cloud

CPU time has long been a remaining problem for large-scale batch mode based scientific computing applications. To address this time-consuming problem, a container-based private cloud was employed, and a novel task-resource mapping algorithm was developed. Firstly, the execution features of typical batch mode codes were extracted and then computing jobs were formulated as a coarseness acyclic DAG. Secondly, to guarantee both job makespan and resource utilization, a novel task-resource mapping algorithm, along with container pre-planning and worst-case-first task placement phases, were developed. Finally, a typical Computational Marine Hydrodynamics software, Rotorysics, with a different scale of input data matrix was used as benchmark software. To manifest the effectiveness of the proposed method, a number of numerical examples were given via CloudSim and a small-medium containerized private cloud platform was adopted with three practical study cases. The computational results show that 1) compared with the traditional HPC workstation computing solution, container-based cloud solution shows significant savings in makespan by more than 6 times. 2) the new method is scalable to address bigger size batch computing problem up to a run matrix 108,.

Quality Assurance and Quality Control of Surfactants for Field-Scale Enhanced-Oil-Recovery Pilot Projects

Summary Alkaline/surfactant/polymer (ASP) flooding is an enhanced-oil-recovery (EOR) technique that involves the injection of a solution of surfactant, alkali, and polymer into an oil reservoir to mobilize and produce the remaining oil. There are several pattern-flood pilots in progress or that will soon be executed to evaluate ASP at a scale relevant to commercial-scale application. The quantities of surfactants needed for these pilots and potential future commercial-scale applications are large (hundreds to thousands of tonnes) and necessitate large-scale manufacture using existing processes and plants for the different manufacturing steps. These operate under slightly different process conditions than those used to make the smaller quantity (50 to 400 kg) of the reference blend used to design the formulation in the laboratory. The upscaling of the surfactant production itself is an essential step to enable field-scale implementation of ASP. To ensure and control the quality of the surfactants produced for pilots with Shell interests, a stage-gated quality assurance/quality control (QA/QC) program was designed and executed. The application of the QA/QC process for a high- and a low-active-matter surfactant-blend concentrate (approximately 60% and 20% active, respectively) is used to illustrate the process. The early definition of the QA/QC program provided a framework with clearly defined stages for upscaling from laboratory- to large-scale production. The definition of analytical and performance-based laboratory experiments with upfront-defined specifications (minimum and maximum values) and repeatability allowed for clear, unambiguous decisions. Correlations between composition and performance that were developed dependent on pilot-scale production were essential to assure the performance of the larger-scale production. Corefloods, used as the ultimate performance check, showed virtually identical performance for pilot-scale prepared surfactants and surfactants from different large-scale batches. The paper illustrates that consistent industrial-scale production of surfactants for application in chemical EOR (CEOR) is feasible. To ensure the quality of such surfactant requires a detailed QA/QC program. The successful execution of the QA/QC program for the surfactants for the pattern pilots ensures that the produced large-scale surfactant blend performs as the reference blend used to design the formulation.

An intensive, large-scale batch culture system to produce the calanoid copepod, Acartia tonsa

A major obstacle to the development of hatchery production for juveniles of many marine species is the difficulty in successfully feeding early larvae. Copepods contribute to the natural diet of most marine fish larvae and feature characteristics ideal for early larval feeds including small size and suitable nutrient content. However, the use of copepods as larval feeds is limited by the inability to consistently produce them in sufficient quantities to support large-scale fish culture. Here, an innovative design for an intensive, indoor batch culture system to produce the calanoid copepod Acartia tonsa (Dana 1849), a prime candidate for use as a live food item, is described. The system features integrated grow-out and egg-production units that can be operated sequentially by 2.5 full-time employees to produce a predictable daily output of nauplii for use as live feed. The system output was on average 22 million eggs d−1 (21,955,420 ± 8,709,668) with an average hatch rate of 49% (49.1 ± 14.8) over three seasons.

Syringe Filling of a High-Concentration mAb Formulation: Experimental, Theoretical, and Computational Evaluation of Filling Process Parameters That Influence the Propensity for Filling Needle Clogging

This article summarizes experimental, theoretical, and computational assessments performed to understand the effect of filling and suck-back cycle factors on fluid behaviors that increase the propensity for filling needle clogging. Product drying under ambient conditions decreased considerably when the liquid front was altered from a droplet or meniscus at the needle tip to a point approximately 5 mm inside the needle. Minimizing the variation in size of product droplet formed after the fill cycle is critical to achieve a uniform meniscus height after the suck-back cycle. Several factors were found to contribute to droplet size variability, including filling and suck-back pump speed, suck-back volume, and product temperature. Filling trials and the computational fluid dynamics simulations showed that product meniscus stability during the suck-back cycle can be improved by reducing the suck-back flow rate. The computational fluid dynamics simulations also showed that a decrease in contact angle had the greatest effect in reducing meniscus stability. As the number of filling line stoppages increases, the product buildup at the needle increases. The interaction between stoppages and the number of dispenses between stoppages was established to minimize product buildup at the filling needle. Improved suck-back control was shown to improve process capability of large-scale batches.

Comments on “A Large-Scale Concurrent Data Anonymous Batch Verification Scheme for Mobile Healthcare Crowd Sensing”

As an important application of the Internet of Things technologies, mobile healthcare crowd sensing (MHCS) still has challenging issues, such as privacy protection and efficiency. Quite recently in the IEEE Internet of Things Journal (DOI: 10.1109/JIOT.2018.2828463), Liu et al. proposed a large-scale concurrent data anonymous batch verification scheme for MHCS, claiming to provide batch authentication, nonrepudiation, and anonymity. However, after a close look at the scheme, we point out that the scheme suffers two types of signature forgery attacks and hence fails to achieve the claimed security properties. In addition, a reasonable and rigorous probability analysis indicates that the security reduction from the security of the scheme to the hardness of the computational Diffie–Hellman problem is invalid. We hope that similar design flaws can be avoided in future design of anonymous batch verification schemes for MHCS.

Temperature-Responsive Magnetic Nanoparticles for Enabling Affinity Separation of Extracellular Vesicles.

Small magnetic nanoparticles that have surfaces decorated with stimuli-responsive polymers can be reversibly aggregated via a stimulus, such as temperature, to enable efficient and rapid biomarker separation. To fully realize the potential of these particles, the synthesis needs to be highly reproducible and scalable to large quantity. We have developed a new synthesis for temperature-responsive magnetic nanoparticles via an in situ co-precipitation process of Fe2+/Fe3+ salts at room temperature with poly(acrylic acid)- block-poly( N-isopropylacrylamide) diblock co-polymer template, synthesized via the reversible addition-fragmentation chain-transfer polymerization method. These particles were 56% polymer by weight with a 6.5:1 Fe/COOH ratio and demonstrated remarkable stability over a 2 month period. The hydrodynamic diameter remained constant at ∼28 nm with a consistent transition temperature of 34 °C, and the magnetic particle separation efficiency at 40 °C was ≥95% over the 2 month span. These properties were maintained for all large-scale synthesis batches. To demonstrate the practical utility of the stimuli-responsive magnetic nanoparticles, the particles were incorporated into a temperature-responsive binary reagent system and efficiently separated a model protein biomarker (mouse IgG) as well as purified extracellular vesicles derived from a human biofluid, seminal plasma. The ease of using these particles will prove beneficial for various biomedical applications.

A unified DC programming framework and efficient DCA based approaches for large scale batch reinforcement learning

We investigate a powerful nonconvex optimization approach based on Difference of Convex functions (DC) programming and DC Algorithm (DCA) for reinforcement learning, a general class of machine learning techniques which aims to estimate the optimal learning policy in a dynamic environment typically formulated as a Markov decision process (with an incomplete model). The problem is tackled as finding the zero of the so-called optimal Bellman residual via the linear value-function approximation for which two optimization models are proposed: minimizing the $$\ell _{p}$$ -norm of a vector-valued convex function, and minimizing a concave function under linear constraints. They are all formulated as DC programs for which attractive DCA schemes are developed. Numerical experiments on various examples of the two benchmarks of Markov decision process problems—Garnet and Gridworld problems, show the efficiency of our approaches in comparison with two existing DCA based algorithms and two state-of-the-art reinforcement learning algorithms.

2-D MEMS Scanner for Handheld Multispectral Dual-Axis Confocal Microscopes

We describe a 2-D microelectromechanical systems (MEMS) scanner for a handheld multispectral confocal microscope for early detection and diagnosis of cervical cancer. This paper is an expansion of work originally reported in the Proceedings of IEEE International Conference on Optical MEMS and Nanophotonics 2012. The MEMS scanner and fabrication process has been designed to improve performance for the dual-axis confocal microscopy architecture. Dual-axis confocal microscopy achieves comparable transverse and depth resolution to high numerical aperture (NA) single-axis confocal microscopy but achieves longer working distance by utilizing low-NA optics. The MEMS scanner has an inner gimbal design with torsional flexures separated from the reflectors to reduce light loss and oxide-free outer axis torsional flexures by utilizing poly vias for electrical access to the inner gimbal electrodes. The devices are large-scale batch fabricated using a double layer silicon-on-insulator (SOI) process and predice postreleasing of dies. The scanner has electrostatic optical deflection angles of 2° for the single-sided inner axis at 75 V and ±3° for the outer axis at 120 V. The device has resonance frequencies of ~2.48 kHz and ~348 Hz for the inner and outer axis torsional modes, respectively. Reflectance and fluorescence images with 650 μm × 800 μm field of view are demonstrated at 15 frames/s. The transverse (axial) resolutions are 4.78 μm (6.2 μm), 5.77 μm (6.2 μm), and 7.45 μm (5.6 μm) for wavelengths of 561, 662, and 781 nm, respectively.

Lost in migration: document quality for batch conversion to PDF/A

PurposeChanges in file format specifications challenge long-term preservation of digital documents. Digital archives thus often focus on specific file formats that are well suited for long-term preservation, such as the PDF/A format. Since only few customers submit PDF/A files, digital archives may consider converting submitted files to the PDF/A format. The paper aims to discuss these issues.Design/methodology/approachThe authors evaluated three software tools for batch conversion of common file formats to PDF/A-1b: LuraTech PDF Compressor, Adobe Acrobat XI Pro and 3-HeightsTM Document Converter by PDF Tools. The test set consisted of 80 files, with 10 files each of the eight file types JPEG, MS PowerPoint, PDF, PNG, MS Word, MS Excel, MSG and “web page.”FindingsBatch processing was sometimes hindered by stops that required manual interference. Depending on the software tool, three to four of these stops occurred during batch processing of the 80 test files. Furthermore, the conversion tools sometimes failed to produce output files even for supported file formats: three (Adobe Pro) up to seven (LuraTech and 3-HeightsTM) PDF/A-1b files were not produced. Since Adobe Pro does not convert e-mails, a total of 213 PDF/A-1b files were produced. The faithfulness of each conversion was investigated by comparing the visual appearance of the input document with that of the produced PDF/A-1b document on a computer screen. Meticulous visual inspection revealed that the conversion to PDF/A-1b impaired the information content in 24 of the converted 213 files (11 percent). These reproducibility errors included loss of links, loss of other document content (unreadable characters, missing text, document part missing), updated fields (reflecting time and folder of conversion), vector graphics issues and spelling errors.Originality/valueThese results indicate that large-scale batch conversions of heterogeneous files to PDF/A-1b cause complex issues that need to be addressed for each individual file. Even with considerable efforts, some information loss seems unavoidable if large numbers of files from heterogeneous sources are migrated to the PDF/A-1b format.

Bacterial community changes in an industrial algae production system

While microalgae are a promising feedstock for production of fuels and other chemicals, a challenge for the algal bioproducts industry is obtaining consistent, robust algae growth. Algal cultures include complex bacterial communities and can be difficult to manage because specific bacteria can promote or reduce algae growth. To overcome bacterial contamination, algae growers may use closed photobioreactors designed to reduce the number of contaminant organisms. Even with closed systems, bacteria are known to enter and cohabitate, but little is known about these communities. Therefore, the richness, structure, and composition of bacterial communities were characterized in closed photobioreactor cultivations of Nannochloropsis salina in F/2 medium at different scales, across nine months spanning late summer-early spring, and during a sequence of serially inoculated cultivations. Using 16S rRNA sequence data from 275 samples, bacterial communities in small, medium, and large cultures were shown to be significantly different. Larger systems contained richer bacterial communities compared to smaller systems. Relationships between bacterial communities and algae growth were complex. On one hand, blooms of a specific bacterial type were observed in three abnormal, poorly performing replicate cultivations, while on the other, notable changes in the bacterial community structures were observed in a series of serial large-scale batch cultivations that had similar growth rates. Bacteria common to the majority of samples were identified, including a single OTU within the class Saprospirae that was found in all samples. This study contributes important information for crop protection in algae systems, and demonstrates the complex ecosystems that need to be understood for consistent, successful industrial algae cultivation. This is the first study to profile bacterial communities during the scale-up process of industrial algae systems.

Optimization and scale up of microfluidic nanolipomer production method for preclinical and potential clinical trials

BackgroundThe process of optimization and fabrication of nanoparticle synthesis for preclinical studies can be challenging and time consuming. Traditional small scale laboratory synthesis techniques suffer from batch to batch variability. Additionally, the parameters used in the original formulation must be re-optimized due to differences in fabrication techniques for clinical production. Several low flow microfluidic synthesis processes have been reported in recent years for developing nanoparticles that are a hybrid between polymeric nanoparticles and liposomes. However, use of high flow microfluidic synthetic techniques has not been described for this type of nanoparticle system, which we will term as nanolipomer. In this manuscript, we describe the successful optimization and functional assessment of nanolipomers fabricated using a microfluidic synthesis method under high flow parameters.ResultsThe optimal total flow rate for synthesis of these nanolipomers was found to be 12 ml/min and flow rate ratio 1:1 (organic phase: aqueous phase). The PLGA polymer concentration of 10 mg/ml and a DSPE-PEG lipid concentration of 10% w/v provided optimal size, PDI and stability. Drug loading and encapsulation of a representative hydrophobic small molecule drug, curcumin, was optimized and found that high encapsulation efficiency of 58.8% and drug loading of 4.4% was achieved at 7.5% w/w initial concentration of curcumin/PLGA polymer. The final size and polydispersity index of the optimized nanolipomer was 102.11 nm and 0.126, respectively. Functional assessment of uptake of the nanolipomers in C4-2B prostate cancer cells showed uptake at 1 h and increased uptake at 24 h. The nanolipomer was more effective in the cell viability assay compared to free drug. Finally, assessment of in vivo retention in mice of these nanolipomers revealed retention for up to 2 h and were completely cleared at 24 h.ConclusionsIn this study, we have demonstrated that a nanolipomer formulation can be successfully synthesized and easily scaled up through a high flow microfluidic system with optimal characteristics. The process of developing nanolipomers using this methodology is significant as the same optimized parameters used for small batches could be translated into manufacturing large scale batches for clinical trials through parallel flow systems.

Automated radiosynthesis of Al[18F]PSMA-11 for large scale routine use

ObjectivesWe report a reproducible automated radiosynthesis for large scale batch production of clinical grade Al[18F]PSMA-11. MethodsA SynthraFCHOL module was optimized to synthesize Al[18F]PSMA-11 by Al[18F]-chelation. ResultsAl[18F]PSMA-11 was synthesized within 35min in a yield of 21 ± 3% (24.0 ± 6.0GBq) and a radiochemical purity > 95%. Batches were stable for 4h and conform the European Pharmacopeia guidelines. ConclusionsThe automated synthesis of Al[18F]PSMA-11 allows for large scale production and distribution of Al[18F]PSMA-11.

Impact of continuous flow chemistry in the synthesis of natural products and active pharmaceutical ingredients

We present a comprehensive review of the advent and impact of continuous flow chemistry with regard to the synthesis of natural products and drugs, important pharmaceutical products and definitely responsible for a revolution in modern healthcare. We detail the beginnings of modern drugs and the large scale batch mode of production, both chemical and microbiological. The introduction of modern continuous flow chemistry is then presented, both as a technological tool for enabling organic chemistry, and as a fundamental research endeavor. This part details the syntheses of bioactive natural products and commercial drugs.

Influence of feedstock-to-inoculum ratio on performance and microbial community succession during solid-state thermophilic anaerobic co-digestion of pig urine and rice straw

This study investigated the effect of the feedstock-to-inoculum (F/I) ratio on performance of the solid-state anaerobic co-digestion of pig urine and rice straw inoculated with a solid digestate, and clarified the microbial community succession. A 44-day biochemical methane potential test at F/I ratios of 0.5, 1, 2 and 3 at 55 °C and a 35-day large-scale batch test at F/I ratios of 0.5 and 3 at 55 °C were conducted to investigate the effects of F/I ratio on anaerobic digestibility and analyze microbial community succession, respectively. The highest cumulative methane yield was 353.7 m3/t VS in the large-scale batch test. Volatile fatty acids did not accumulate at any F/I ratios. The volatile solids reduction rate was highest at a F/I ratio of 0.5. Microbial community structures were similar between F/I ratios of 3 and 0.5, despite differences in digestion performance, suggesting that stable operation can be achieved at these ratios.

Scalable colloidal synthesis of uniform Bi2S3nanorods as sensitive materials for visible-light photodetectors

A facile colloidal chemistry method is reported for synthesis of uniform Bi2S3 nanorods in a mixed solution of oleylamine with other organic amines including n-dodecylamine (C12), n-octylamine (C8), and n-hexylamine (C6). The nanorod length can be tuned through the carbon-chain length of these amines and importantly multigrams of Bi2S3 nanorods can be readily synthesized in a single scaled-up batch. Current–voltage (I–V) measurements showed that the Bi2S3 nanorods, obtained from both the small and large-scale batches or ones with different chain-length amines, exhibit fast light response characteristics (at the sub-second scale) with an obviously enhanced photocurrent (or photoconductivity) under broad-spectrum white light or monochromatic visible light of different wavelengths. The as-obtained nanorods, as determined by time-dependent current (I–t) curves, also exhibit excellent photoresponsive stability and reproducibility with the on–off switch of light. The photoconductivity enhancement in the Bi2S3 nanorods is assigned to the efficient electron–hole pair separation due to a hole-trapping mechanism. These results indicate the promising potential of Bi2S3 nanorods for optoelectronic device applications including photodetection (sensing), optical switch, photocatalysis, and photovoltaics within the visible spectrum range.